Aims. The optimal procedure for the treatment of ossification of the posterior longitudinal ligament (OPLL) remains controversial. The aim of this study was to compare the outcome of anterior cervical ossified posterior longitudinal ligament en bloc resection (ACOE) with posterior laminectomy and fusion with bone graft and internal fixation (PTLF) for the surgical management of patients with this condition. Methods. Between July 2017 and July 2019, 40 patients with cervical OPLL were equally randomized to undergo surgery with an ACOE or a PTLF. The clinical and radiological results were compared between the two groups. Results. The Japanese Orthopaedic Association (JOA) score and recovery rate in the ACOE group were significantly higher than those in the PTLF group during two years postoperatively, provided that the canal occupying ratio (COR) was > 50%, or the K-line was negative. There was no significant difference in JOA scores and rate of recovery between the two groups in those in whom the COR was < 50%, or the K-line was positive. There was no significant difference in the Cobb angle between C2 and C7, sagittal vertical axis, cervical range of motion (ROM), and complications between the two groups. Conclusion. Compared with PTLF, ACOE is a preferred surgical approach for the surgical management of patients with cervical OPLL in that it offers a better therapeutic outcome when the COR is > 50%, or the K-line is negative, and it also preserves better cervical curvature and sagittal balance. The prognosis of ACOE is similar to that of PTLE when the COR is < 50%, or the K-line is positive. Cite this article: Bone Joint J 2023;105-B(4):412–421

Aims. Surgical approaches to cervical ossification of the posterior longitudinal ligament (OPLL) remain controversial. The purpose of the present study was to analyze and compare the long-term neurological recovery following anterior decompression with fusion (ADF) and posterior laminectomy and fusion with bone graft and internal fixation (PLF) based on > ten-year follow-up outcomes in a single centre. Methods. Included in this retrospective cohort study were 48 patients (12 females; mean age 55.79 years (SD 8.94)) who were diagnosed with cervical OPLL, received treatment in our centre, and were followed up for 10.22 to 15.25 years. Of them, 24 patients (six females; mean age 52.88 years (SD 8.79)) received ADF, and the other 24 patients (five females; mean age 56.25 years (SD 9.44)) received PLF. Clinical data including age, sex, and the OPLL canal-occupying ratio were analyzed and compared. The primary outcome was Japanese Orthopaedic Association (JOA) score, and the secondary outcome was visual analogue scale neck pain. Results. Compared with the baseline, neurological function improved significantly after surgery in all patients of both groups (p < 0.001). The JOA recovery rate in the ADF group was significantly higher than that in the PLF group (p < 0.001). There was no significant difference in postoperative cervical pain between the two groups (p = 0.387). The operating time was longer and intraoperative blood loss was greater in the PLF group than the ADF group. More complications were observed in the ADF group than in the PLF group, although the difference was not statistically significant. Conclusion. Long-term neurological function improved significantly after surgery in both groups, with the improvement more pronounced in the ADF group. There was no significant difference in postoperative neck pain between the two groups. The operating time was shorter and intraoperative blood loss was lower in the ADF group; however, the incidence of perioperative complications was higher. Cite this article: Bone Jt Open 2024;5(9):768–775

Ossification of the posterior longitudinal ligament (OPLL) is a condition found predominantly in the oriental population and is rarely seen in non orientals. OPLL can present with cervical canal stenosis and myelopathy (including central cord syndrome), often following minor trauma. Co-existence of OPLL with diffuse idiopathic skeletal hyperostosis (DISH) is a rare condition and very few reports of such patients exist in literature. Here we report the case of a Caucasian with co-existing DISH and OPLL, presenting with acute central cord syndrome associated with fracture of the ossification. A 64 year old Caucasian farmer was transferred to our spinal unit with weakness in the right upper limb following a road traffic accident. On examination he had hyperaesthesia in both upper limbs and motor power of grade 4 in the right upper limb with a distal motor power of grade 3 in the hand. There was no motor deficit in the left upper limb or lower limbs. Radiographs revealed an ossification of the posterior longitudinal ligament with a break at C2 and C3 levels. He also had exuberant soft tissue ossification in the cervical and thoracic spines, suggestive of diffuse idiopathic skeletal hyperostosis (DISH). He recovered completely in 6 weeks with non operative treatment. Fracture of the posterior longitudinal ligament has not been widely reported, although it is possibly more prevalent than is recognised. We report this case in order to highlight the importance of recognising this condition in non oriental populations and to demonstrate that non operative treatment has a good prognosis

We report 14 cases of symptomatic ossification of the posterior longitudinal ligament (OPLL) diagnosed in non-oriental men between 1978 and 1985. All 14 patients had incomplete spinal cord syndromes due to OPLL in the cervical spine and had been referred undiagnosed from other institutions. Twelve had severe myelopathy and seven were wheelchair-bound before OPLL was diagnosed, while six patients had had operations elsewhere for their neurological dysfunction. There was a close association between OPLL and diffuse idiopathic skeletal hyperostosis (Forestier's disease) on plain radiographs, seven patients having both disorders. Enhanced CT scans proved to be the best diagnostic method for the localisation of cord compression, and magnetic resonance imaging, used on four recent cases, provided the best visualisation of the extent of involvement in the sagittal plane. We aim to heighten awareness of OPLL in non-orientals, in whom the clinical features, histological characteristics, and radiographic patterns are very similar to those of oriental patients

In this series, 15 patients with ossification of the posterior longitudinal ligament underwent anterior decompression to relieve moderate or severe myelopathy, which in 11 included urinary disturbance. The operation consisted of partial resection of the vertebrae, release of the ossified plaque from the surrounding tissue and the insertion of an iliac bone graft. The extent of ossification was confirmed by computerised tomography before and after operation. The plaque was completely detached and moved forward in half of the patients, but only partially moved in the remainder. Symptoms improved considerably. Urinary disturbance disappeared in all patients, but sensory disturbance was left in most. Two patients had prolonged symptoms which were not relieved despite the complete release of the ossified defect

Ossification of the posterior longitudinal ligament in the cervical region is generally regarded as a rare disease, though a Japanese series of 185 cases has been reported. The main symptoms arise from a myelopathy, the degree of which varies from moderate to severe, due to stenosis of the spinal canal. In order to clarify the relationship between the severity of symptoms and the cross-sectional area of ossification, axial transverse tomography of the cervical spine has been carried out on twenty-six patients at intervals of 5 millimetres over the full extent of the ossification. In this way the cross-sectional areas of the ossified tissue and of the spinal canal were calculated. The former varied from a minimum of 0.8 to a maximum of 1.8 square centimetres. In cases of severe myelopathy the ossification was mainly at the fourth and fifth cervical levels and the stenosis ration exceeded 30 per cent

In 141 patients with ossification of posterior longitudinal ligament, open-door expansive laminoplasty was done from 1980 to 1998. A follow-up study was made. 10 patients with cervical cord injury and cerebral diseases before or after operation were excluded. 121 of 131 patients were followd directly one to fifteen years(mean: 5 years and 3 months). Subjects included 93 male and 28 female. At the time of operation, their ages ranged from 40 to 80 years(mean:59.5). Operative results were evaluated using the Japanese Orthopaedic Association’s Score(JOA Score) and Hirabayashi’s improvement rate. X-ray was taken to measure the range of cervical spine motion, curvature of the cervical spine and progression of ossified masses. Preoperative JOA scores ranged from 2 to 14 points(mean:9.1), postoperative JOA scores ranged 7 to 17 points(mean:14.1). The mean improvement rate was 62%. The range of cervical spine motion decreased from 26.6 degrees prior to operation to 10.8 degrees after operation. Lordotic curvature also fell from 11.8 degrees before operation to 6.6 degrees after operation. In 20 patients, the postoperative kyphotic curvature increased to 5 degrees of more, although no difference was seen in their improvement rates compared with patients whose lordosis remained unchanged. 80 of 121 patients experienced progression of ossified masses. Three patients underwent additional laminectomy due to progression of ossification or insufficient expansion. Operation took an average 80 minutes and mean amount of blood loss was 215 ml. No patients had postoperative motor paralysis caused by C5 or C6 nerve damage and no serious complications were seen

We reviewed 75 patients (57 men and 18 women), who had undergone tension-band laminoplasty for cervical spondylotic myelopathy (42 patients) or compression myelopathy due to ossification of the posterior longitudinal ligament (33 patients) and had been followed for more than ten years. Clinical and functional results were estimated using the Japanese Orthopaedic Association score. The rate of recovery and the level of postoperative axial neck pain were also recorded. The pre- and post-operative alignment of the cervical spine (Ishihara curve index indicating lordosis of the cervical spine) and the range of movement (ROM) of the cervical spine were also measured. The mean rate of recovery of the Japanese Orthopaedic Association score at final follow-up was 52.1% (. sd. 24.6) and significant axial pain was reported by 19 patients (25.3%). Axial pain was reported more frequently in patients with ossification of the posterior longitudinal ligament than in those with cervical spondylotic myelopathy (p = 0.027). A kyphotic deformity was not seen post-operatively in any patient. The mean ROM decreased post-operatively from 32.8° (. sd. 12.3) to 16.2° (. sd. 12.3) (p < 0.001). The mean ROM ratio was 46.9% (. sd. 28.1) for all the patients. The mean ROM ratio was lower in patients with ossification of the posterior longitudinal ligament than in those with cervical spondylotic myelopathy (p < 0.001). Compared to those with cervical spondylotic myelopathy, patients with ossification of the posterior longitudinal ligament had less ROM and more post-operative axial neck pain

The October 2023 Spine Roundup. 360. looks at: Cutting through surgical smoke: the science of cleaner air in spinal operations; Unlocking success: key factors in thoracic spine decompression and fusion for ossification of the posterior longitudinal ligament; Deep learning algorithm for identifying cervical cord compression due to degenerative canal stenosis on radiography; Surgeon experience influences robotics learning curve for minimally invasive lumbar fusion; Decision-making algorithm for the surgical treatment of degenerative lumbar spondylolisthesis of L4/L5; Response to preoperative steroid injections predicts surgical outcomes in patients undergoing fusion for isthmic spondylolisthesis

Aims. This study, using a surgeon-maintained database, aimed to explore the risk factors for surgery-related complications in patients undergoing primary cervical spine surgery for degenerative diseases. Methods. We studied 5,015 patients with degenerative cervical diseases who underwent primary cervical spine surgery from 2012 to 2018. We investigated the effects of diseases, surgical procedures, and patient demographics on surgery-related complications. As subcategories, the presence of cervical kyphosis ≥ 10°, the presence of ossification of the posterior longitudinal ligament (OPLL) with a canal-occupying ratio ≥ 50%, and foraminotomy were selected. The surgery-related complications examined were postoperative upper limb palsy (ULP) with a manual muscle test (MMT) grade of 0 to 2 or a reduction of two grade or more in the MMT, neurological deficit except ULP, dural tear, dural leakage, surgical-site infection (SSI), and postoperative haematoma. Multivariate logistic regression analysis was performed. Results. The significant risk factors (p < 0.050) for ULP were OPLL (odds ratio (OR) 1.88, 95% confidence interval (CI) 1.29 to 2.75), foraminotomy (OR 5.38, 95% CI 3.28 to 8.82), old age (per ten years, OR 1.18, 95% CI 1.03 to 1.36), anterior spinal fusion (OR 2.85, 95% CI 1.53 to 5.34), and the number of operated levels (OR 1.25, 95% CI 1.11 to 1.40). OPLL was also a risk factor for neurological deficit except ULP (OR 5.84, 95% CI 2.80 to 12.8), dural tear (OR 1.94, 95% CI 1.11 to 3.39), and dural leakage (OR 3.15, 95% CI 1.48 to 6.68). Among OPLL patients, dural tear and dural leakage were frequently observed in those with a canal-occupying ratio ≥ 50%. Cervical rheumatoid arthritis (RA) was a risk factor for SSI (OR 10.1, 95% CI 2.66 to 38.4). Conclusion. The high risk of ULP, neurological deficit except ULP, dural tear, and dural leak should be acknowledged by clinicians and OPLL patients, especially in those patients with a canal-occupying ratio ≥ 50%. Foraminotomy and RA were dominant risk factors for ULP and SSI, respectively. An awareness of these risks may help surgeons to avoid surgery-related complications in these conditions. Cite this article: Bone Joint J 2021;103-B(1):157–163

The August 2014 Spine Roundup. 360 . looks at: rhBMP complicates cervical spine surgery; posterior longitudinal ligament revisited; thoracolumbar posterior instrumentation without fusion in burst fractures; risk modelling for VTE events in spinal surgery; the consequences of dural tears in microdiscectomy; trends in revision spinal surgery; radiofrequency denervation likely effective in facet joint pain and hooks optimally biomechanically transition posterior instrumentation

Postoperative radiculopathy is a complication of posterior cervical decompression associated with tethering of the nerve root. We reviewed retrospectively 287 consecutive patients with cervical compression myelopathy who had been treated by multilevel cervical laminectomy and identified 37 (12.9%) with postoperative radiculopathy. There were 27 men and ten women with a mean age of 56 years at the time of operation. The diagnosis was either cervical spondylosis (25 patients) or ossification of the posterior longitudinal ligament (12 patients). Radiculopathy was observed from four hours to six days after surgery. The most frequent pattern of paralysis was involvement of the C5 and C6 roots of the motor-dominant type. The mean time for recovery was 5.4 months (two weeks to three years). The results at follow-up showed that the rate of motor recovery was negatively related to the duration of complete recovery of postoperative radiculopathy (γ = −0.832, p < 0.01) and that patients with spondylotic myelopathy had a significantly better rate of clinical recovery than those with ossification of the posterior longitudinal ligament (t = 2.960, p < 0.01). Postoperative radiculopathy may be prevented by carrying out an anterior decompression in conjunction with spinal fusion, which will achieve stabilisation and directly remove compression of the cord at multiple levels

Seven men with a mean age of 63.9 years (59 to 67) developed dysphagia because of oesophageal compression with ossification of the anterior longitudinal ligament (OALL) and radiculomyelopathy due to associated stenosis of the cervical spine. The diagnosis of OALL was made by plain lateral radiography and classified into three types; segmental, continuous and mixed. Five patients had associated OALL in the thoracic and lumbar spine without ossification of the ligamentum flavum. All underwent removal of the OALL and six had simultaneous decompression by removal of ossification of the posterior longitudinal ligament or a bony spur. All had improvement of their dysphagia. Because symptomatic OALL may be associated with spinal stenosis, precise neurological examination is critical. A simultaneous microsurgical operation for patients with OALL and spinal stenosis gives good results without serious complications

The effect of rheumatoid arthritis on the anatomy of the cervical spine has not been clearly documented. We studied 129 female patients, 90 with rheumatoid arthritis and 39 with other pathologies (the control group). There were 21 patients in the control group with a diagnosis of cervical spondylotic myelopathy, and 18 with ossification of the posterior longitudinal ligament. All had plain lateral radiographs taken of the cervical spine as well as a reconstructed CT scan. The axial diameter of the width of the pedicle, the thickness of the lateral mass, the height of the isthmus and internal height were measured. The transverse diameter of the transverse foramen (d1) and that of the spinal canal (d2) were measured, and the ratio d1/d2 calculated. The width of the pedicles and the thickness of the lateral masses were significantly less in patients with rheumatoid arthritis than in those with other pathologies. The area of the transverse foramina in patients with rheumatoid arthritis was significantly greater than that in the other patients. The ratio of d1 to d2 was not significantly different. A high-riding vertebral artery was noted in 33.9% of the patients with rheumatoid arthritis and in 7.7% of those with other pathologies. This difference was statistically significant. In the rheumatoid group there was a significant correlation between isthmus height and vertical subluxation and between internal height and vertical subluxation

Sprung back is one of the commonest causes of low back pain. Its characteristic features are described. It is caused by rupture of the posterior ligaments of the spine, including sometimes the posterior longitudinal ligament and annulus fibrosus. The manner in which it is produced and its mechanical effects are discussed in detail

Disc degeneration starts as an avascular necrosis. In the lower lumbar area the discs deteriorate early because of mechanical stresses. During certain early periods of degenerative changes a mechanical disorder between the annulus and the posterior longitudinal ligament may cause tiredness and pain. When the disc is completely degenerated and has lost its physical properties backache disappears

We reviewed the magnetic resonance (MR) images of eight adults with acute hyperextension-dislocation of the cervical spine. The images were obtained to evaluate damage to the spinal cord. All eight patients had disruption of the anterior longitudinal ligament and of the annulus of the intervertebral disc, and separation of the posterior longitudinal ligament from the subjacent vertebra. Some, but not all, showed widening of the disc space, posterior bulging or herniation of the nucleus pulposus, and disruption of the ligamentum flavum. The MR demonstration of these ligament injuries, taken with the clinical and radiographic findings, establishes the mechanism of hyperextension-dislocation, confirms the diagnosis, and is relevant to management

1. The spinal branches of the vertebral artery were injected with a suspension of barium sulphate and the blood supply of the vertebral bodies of the lower four or five cervical vertebrae investigated radiologically. 2. Beneath the posterior longitudinal ligament there is a free dorsal arterial plexus from which a large branch arises to enter the back of the vertebral body. This vessel terminates abruptly at the centre of the body where numerous, much smaller, branches radiate towards the upper and lower surfaces. 3. The possible significance of the form of the intravertebral arteries is considered in relation to embolic lesion in vertebral bodies

We treated 12 patients with multilevel stenosis of the cervical canal after spondylosis or ossification of the posterior longitudinal ligament by an expansive open-door laminoplasty, stabilised by using an anchor system. The preoperative sagittal diameter of the canal was 9.8 mm(±2.2) which was increased to 16.1 mm (±2.9) after surgery. The mean expansion ratio of the canal was 64% (42 to 100). The anchoring systems did not fail during the follow-up period (mean 29.5 months), and the decompression was maintained. The use of anchor systems to stabilise the posterior elements after laminoplasty is a simple and effective technique for maintaining the increased sagittal diameter of the canal

Background. Microdiscectomy involves substantial aggressive excision of disc material from the intervertebral space to prevent reherniation. However, the recent trend is towards conservative disc removal and simple fragment excision (sequestrectomy). Aim. To compare the clinical outcome of microdiscectomy and sequestrectomy. Methods. During the 2-year study period, we performed 196 lumbar microdiscectomies for disc herniation. One hundred and one patients met the inclusion criteria: unilateral single level lumbar disc herniation. Cases suitable for sequestrectomy were based on intraoperative assessment (stable fibrous ring without significant disc bulge; posterior longitudinal ligament perforation of < 5mm). Results. Five patients were lost to follow-up, 72 patients underwent conventional microdiscectomy and 24 patients were suitable for sequestrectomy and included in the final analysis. There was no significant difference in terms of age and pre-operative VAS in both groups (p >0.05, unpaired t test. In the microdiscectomy group, 17/31 patients with motor deficit and 34/66 patients with sensory deficit showed post-operative improvement, but in sequestrectomy group, only 1 of 5 patients with motor deficit and 8 of 13 with sensory deficit recovered but this was not statistically significant (p>0.05, Fisher's exact test). Conclusion. In the sequestrectomy group, patients had significantly better improvement in VAS score. There was no significant difference between either group with regards to reherniation or post-operative neurological deficit. In a selected group of patients with single level lumbar disc herniation, clinical outcome of sequestrectomy is comparable to conventional microdiscectomy

The evaluation of early results of combined percutaneous pedicle screw fixation and kyphoplasty for the management of thoraco-lumbar burst fractures. Between October 2008 and April 2009, 9 patients with thoracolumbar burst fractures underwent percutaneous short-segment pedicle screw fixation and augmentation kyphoplasty with calcium phosphate cement. All patients were selected according to the type of fracture (unstable type A3 fractures based on the Magerl classification) the absence of neurological signs and an intact posterior longitudinal ligament on the pre-operative MRI scan. Patient demographics, co-morbidities and complications were recorded. The main endpoints included Cobb angle correction, vertebral body height restoration and the length of hospital stay. There were 3 male and 6 female patients with an average age of 43.6 years. The average follow-up was 2.4 months. The mean kyphotic angulation improved from 18.40 pre-operatively to 6, 80 post-operatively. The loss of vertebral body height improved from a mean of 38.7 % pre-operatively to 12.1 % post-operatively. The average duration of surgery was 40 minutes with insignificant blood loss. There were no post-operative complications. The average length of hospital stay was 3.2 days. The combination of percutaneous short-segment pedicle screw fixation supplemented by balloon kypho-plasty for the management of thoracolumbar burst fractures with no neurological deficit offers correction of the normal thoracolumbar anatomy as well as augmentation of the anterior load-bearing column, using a minimally invasive technique. The early results are promising

Ten patients who suffered iatrogenic injury to a vertebral artery during anterior cervical decompression were reviewed to assess the mechanisms of injury, their operative management, and the subsequent outcome. All had been undergoing a partial vertebral body resection for spondylitic radiculopathy or myelopathy (4), tumour (2), ossification of the posterior longitudinal ligament (1), nonunion of a fracture (2), or osteomyelitis (1). The use of an air drill had been responsible for most injuries. The final control of haemorrhage had been by tamponade (3), direct exposure and electrocoagulation (1), transosseous suture (2), open suture (1), or open placement of a haemostatic clip (3). Five patients had postoperative neurological deficits, but most of them resolved. We found direct arterial exposure and control to be safe, quick and reliable. Careful use of the air drill, particularly in pathologically weakened bone, as in infection or tumour, is essential. Arterial injury is best avoided by a thorough knowledge of the anatomical relationships of the artery, the spinal canal, and the vertebral body

Vertebral fracture due to a metabolic bone disease or a neoplastic disease is a common and debilitating condition. It most often is associated with either osteoporosis or metastatic bone disease. Some of the patients suffering from such fractures continue to complain of back pain and deformity despite optimal medical therapy, including radiotherapy and biphosphonates. Vertebroplasty, i.e. transcutaneous injection of bone cement into the vertebral body can serve as an internal fixation device and allows restoration of mechanical strength and partial restoration of the vertebral height. During the year 2000, 17 vertebrae in 12 patients were injected. These were either lumbar or thoracic vertebrae. All patients reported decrease in pain and improved ambulation capacity. Two minor complications were encountered including headache lasting for 72 hours prior to spontaneously resolving. This possibly indicates a transarachnoidal approach, the other complication has been cement leak below the posterior longitudinal ligament. The patient reported pain amelioration. No emergency surgical interventions were necessary to date. Treatment of metastatic bone disease should be staged, with only a few vertebrae injected in each session, to prevent pulmonary embolization. Vertebroplasty appears to allow excellent palliative treatment in patients suffering from unresectable primary tumors of the vertebrae, or more commonly, metastatic bone tumors as well as osteoporotic fractures

Awake Rapid Heavy-Weight Closed Reduction (ARHWCR) with weights from 18 to 72 kg was used to reduce six unilateral and nine bilateral cervical facet dislocations. Frankel grading ranged from A to E. Reduction was achieved in all 15 patients with no neurological deterioration. Motor ASIA score improved from a prereduction mean of 64 points to 73 after reduction. Before and after reduction, MRI studies were done on all 15 patients. ARHWCR was done irrespective of the MRI findings. The MRI results were evaluated by five orthopaedic surgeons, five neurosurgeons and five radiologists. The radiologists reported 55% disc herniation in four neurologically-intact patients. On pre-reduction MRI, 34% of anterior longitudinal ligaments and 64% of posterior longitudinal ligaments were reported to be disrupted. They were reported intact on post-reduction MRI. These findings indicate that MRI studies may be open to misinterpretation. Viewing the prereduction MRI, the orthopaedic and neurosurgeons opted for surgical decompression and reduction in 53% of cases. Looking at the post-reduction MRI, they felt that reduction was adequate in 80.6% of cases, but on personal judgment believed that surgical decompression might be of benefit in the remaining 19.4%. ARHWCR is an effective, safe and rapid way of relieving cord compression. Prereduction MRI, irrespective of the patient’s neurological status, is not indicated in acute cervical facet dislocations and can lead to unnecessary surgical intervention

Introduction: Current diagnostic labels used to dictate the prescription of treatment have been derived from studies of cadavers and surgery performed upon the unconscious patient. Methods: In 800 patients, feedback during aware state surgery was independently recorded . Pain sources were detected by spinal probing and verified by endoscopy in the extra foraminal, epidural, foraminal and intradiscal zones. Results: The nerve was found variously painfully tethered to the ascending facet joint, the superior foraminal ligament, superior notch osteophytes, shoulder osteophytes and directly tethered to the disc. In addition, the disc pad, posterior longitudinal ligament and tissues on the dorsum of the vertebra were found to be individually sensitive. These sources produced both local and referred pain. In two thirds of patients with back pain, the disc itself was quiescent to both external and internal manipulation. In a third of patients, the inflamed nerve produced atypical peripheral radicular symptoms on direct probing. Discussion: These unrecognised pain sites and the atypical peripheral symptoms they produce may lead to atypical presentations and mal-targeted interventions. Their persistence may account for failures following conventional surgery. Endoscopy offers an intriguing method of localising and understanding the pathology that underlies diagnostic labels such as failed back syndrome, failed back surgery syndrome, instability and lateral recess stenosis. It is suggested that future surgery be based upon the findings of spinal probing with endoscopic verification. Dynamic retrolisthesis and olisthesis aggravates inflammation in these foraminal sites

Introduction The precise contribution of the posterior longitudinal ligament (PLL) and disc annulus in the burst fracture setting and their potential relative roles during intra operative reduction manoeuvres remains unclear. The anatomical attachments of the posterosuperior fragment most often associated with canal occlusion and potential neurological compromise are not well described in a reproducible model. Methods Burst fractures were induced using a pendulum impact tester. The jig allowed for accurate positioning in all planes and for precise delivery of both the magnitude and vector of the impact force. This allowed for creation of fracture all three major groups of the AO classification. The A3 (burst fracture) was produced in 10 cadaveric sheep spines by delivering a neutral force vector on a physiologically flexed spine. The morphology of the fracture was confirmed by CT. Subsequent laminectomy was performed and the anatomical attachments of the large fragments were identified. Results The PLL was identified following laminectomy in each case. In six of the ten spines there had been significant disruption of the longitudinal structure of the PLL .In a further two cases there had been stripping of the PLL from the posterior aspect of the vertebral body in association with the retropulsed canal fragment. Subsequent excision of the PLL from the posterior aspects of vertebral body and discs did not compromise the attachment of the retropulsed fragment to the disc annulus in any case. Discussion This study confirms the anatomical relationship between disc fragment and disc annulus in the burst fracture setting. The strong attachment between fragment and disc facilitate rotation of the fragment about this hinge and into the canal. Subsequent intraoperative reduction of this fragment by restoration of disc height may require contribution both from this annular attachment and from tension set up in an intact PLL. The relative contributions of each of these structures in the reduction manoeuvre remains unclear

Purpose. Degenerative changes of the lumbar motion segment often lead to stenosis of the spinal canal or neuroforamen. Axial lumbar interbody fusion (AxiaLIF) is intended to indirectly increase and stabilize foraminal dimensions by restoring disc height in patients with degenerative disc disease, thereby relieving axial and radicular pain. Therefore, this study investigated the effects of AxiaLIF on anterior disc height, posterior disc height, foraminal height and foraminal width as well as to determine the effectiveness of this minimally-invasive technique for indirect decompression and restoration of disc height. Method. Eighty-one patients who underwent a 360 degree lumbar interbody fusion at L4-S1 and L5-S1 with AxiaLIF between November 2008 and May 2010 and satisfied all inclusion criteria were included. The preoperative and three-month postoperative digital radiographs were reviewed and analyzed. Disc heights were measured in the planes of the anterior and posterior surfaces of the adjacent vertebral bodies. Foraminal height was measured as the maximum distance between the inferior margin of the pedicle of the superior vertebra and the superior margin of the pedicle of the inferior vertebra. Foraminal width was measured as the shortest distance between the edge of the superior facet of the caudal vertebra and the posterior edge of inferior endplate of the cranial vertebra. Potential magnification error between pre- and post-operative radiographs was corrected using the anterior vertebral height of L5 vertebra. Results. Our study shows that there is a mean increase of 42.0% in posterior disc height (PDH) at L4-5 and 21.5% in anterior disc height (ADH) at L4-5 and PDH mean increase of 33.6% and 16.3% in ADH at L5-S1 in two-level AxiaLIF cases. Similarly the mean change in foraminal height (FH) was 12.6% at L4-5 and 10.8% at L5-S1 in 2-levels AxiaLIF. The mean change in foraminal width (FW) at L4-L5 was 19.9% and 29.1% at L5-S1 in 2-levels AxiaLIF. In the single level AxiaLIF group, the mean change in PDH was 43.1%, the ADH change was 17.5%, the average change in FH was 14.4%, and mean change in FW was 25.3%. The change is reflected as a percentage of the preoperative value. All changes from preoperative to postoperative values were statistically significant. Conclusion. AxiaLIF appears to be an effective minimally invasive device to increase disc height and neuroforaminal area. Our findings appear equivalent to anterior lumbar interbody fusion and transforaminal lumbar interbody fusion in terms of indirect decompression and increase in disc height. This, in combination with the added benefit of preserving the annulus, anterior longitudinal ligament, and posterior longitudinal ligament, suggests the AxiaLIF is an excellent alternative for this patient population. However, additional follow-up studies are necessary to confirm the long-term ability of the implant to maintain fusion and preserve the improvements in disc and foraminal area

Signal intensity changes of the spinal cord on MRI in chronic cervical myelopathy are thought to be indicative of the prognosis. However, the prognostic significance of signal intensity change remains controversial. The purpose of this study was to investigate the characteristics of MR findings in cervical compression myelopathy that reflect the clinical symptoms and the prognosis and to determine the radiographical and clinical factors that correlate to the prognosis. The subjects were 73 patients who underwent cervical expansive laminoplasty. Their mean age was 64 years, and the mean postoperative follow-up was 3.4 years. The pathological conditions were cervical spondylotic myelopathy in 42 and ossification of the posterior longitudinal ligament in 31.MRI (spin-echo sequence) was performed in all patients. Three patterns of spinal cord signal intensity changes on T1-weighted sequences/T2-weighted sequences were detected as follows: normal/ normal. (N/N); normal/ high signal intensity changes (N/Hi); and low signal intensity changes/high signal intensity changes (Lo/Hi). Surgical outcomes were compared among these three groups. The most useful combination of parameters for predicting prognosis was determined. There were 2 patients with N/N, 67 with N/Hi and 4 with Lo/Hi signal change patterns before surgery. Regarding postoperative recovery, the preoperative Lo/Hi group was significantly inferior to the preoperative N/Hi group. The best combination of predictors for surgical outcomes included age, preoperative signal pattern and duration of symptoms. The low signal intensity changes on T1-weighted sequences indicated a poor prognosis. We speculate that high signal intensity changes on T2-weighted images include a broad spectrum of compressive myelomalacid pathologies and reflect a broad spectrum of recuperative potentials of the spinal cord. Predictors for surgical outcomes are preoperative signal intensity change pattern of the spinal cord on radiological evaluations, age at the time of surgery and chronicity of the disease

Objective: This is a prospective study by an independent observer in which outcomes of 118 anterior lumbar interbody fusions (ALIF), done for discogram-concordant axial low back pain, were evaluated. Aims of the study were to assess overall functional and comprehensive outcomes, predictors of outcome, and whether ALIF alone can be recommended for low back pain. Design: The functional and patient perception assessment was based on a self-evaluation back pain questionnaire, which consisted of Oswestry Disability Index, Pain Chart, Numerical Rating Scales (NRS) for back pain and leg pain and SF-36-Version II. The comprehensive outcomes were categorised as satisfactory (excellent, good or improved) and unsatisfactory (fair, poor, unimproved or worse). Results: Overall, we had 61% satisfactory outcomes. Average percentage change in ODI, NRS and SF-36 PCS scores was statistically quite significant. However, patients who had previous posterolateral fusion at the same level had satisfactory outcome in 81%. Incidence of non-union was higher in two-level fusions than one-level fusions, and cases that developed non-unions had unsatisfactory outcome. Conclusions: ALIF alone can be recommended for discogram-concordant axial low back pain. Radiographic evidence of spondylosis, lysis or listhesis, level of fusion, number of levels fused, floating/non-floating type of fusion, and previous back surgery did not affect the outcome. Cases in which the middle column was stabilised (such as those with (a) intervertebral cages extending up to the posterior longitudinal ligament and (b) previous posterolateral fusion at the same level), and hence biomechanically stable, showed better outcomes. Placement of intervertebral implants mainly in the anterior column lead to distraction of the disc anteriorly, resulting in compression of back wall of the disc and facet joints, and narrowing of intervertebral foramina and spinal canal at that level, thus compromising the outcome

The posterior ligament complex (PLC) in the cervical spine comprises the posterior longitudinal ligament, ligamentum flavum and ligamentum nuchae, the latter homologous with the supraspinous and interspinous ligaments at other levels of the spine. In determining instability, evaluation of the PLC is an essential part of the assessment of cervical spine injuries. Disruption of the PLC occurs following flexion injuries, both in compression and in distraction, and following extension injuries with compression. PLC disruption, diagnosed when clinical examination reveals localised posterior spinal tenderness and/or a widened interspinous gap, is confirmed on standard and dynamic flexion-extension radiographs and MRI. This paper is a retrospective review of 162 patients treated for cervical injuries between 1997 and 2001. There were 83 (51%) distraction flexion, 37 (23%) compression flexion, 18 (11%) compression extension, 17 (10%) vertical compression, six (4%) distraction extension and one (1%) lateral flexion injuries. In 79 patients with pure ligamentous instability, an interspinous stabilisation procedure was performed, using a titanium cable. When associated fractures occurred with PLC disruption, neurologically intact patients were managed conservatively with traction followed by a spinal brace. Patients with a neurological deficit underwent surgery. Using delayed dynamic flexion-extension views and MRI, PLC disruption was diagnosed late in nine flexion distraction injuries without facet dislocation. At follow-up, flexion-extension views showed that all PLC disruptions with associated fractures had stabilised. There were two broken cables in patients who underwent surgery. Patients with cervical instability following trauma may be treated non-operatively when there are associated fractures, while patients with pure ligamentous instability should undergo fusion. Further, to exclude occult PLC disruption, all cervical injuries should be reviewed on flexion-extension views once the paraspinal muscle spasm has settled

The accuracy of pedicle screw placement is essential for successful spinal reconstructive surgery. The authors of several previous studies have described the use of image-based navigational templates for pedicle screw placement. These are designed based on a pre-operative computed tomographic (CT) image that fits into a unique position on an individual's bone, and holes are carefully designed to guide the drill or the pedicle probe through a pre-planned trajectory. The current study was conducted to optimise navigational template design and establish its designing method for safe and accurate pedicle screw placement. Thin-section CT scans were obtained from 10 spine surgery patients including 7 patients with adolescent idiopathic scoliosis (AIS) and three with thoracic ossification of the posterior longitudinal ligament (OPLL). The CT image data were transferred to the commercially available image-processing software and were used to reconstruct a three-dimensional (3D) model of the bony structures and plan pedicle screw placement. These data were transferred to the 3D-CAD software for the design of the template. Care was taken in designing the template so that the best intraoperative handling would be achieved by choosing several round contact surfaces on the visualised posterior vertebral bony structure, such as transverse process, spinous process and lamina. These contact surfaces and holes to guide the drill or the pedicle probe were then connected by a curved pipe. STL format files for the bony models with planned pedicle screw holes and individual templates were prepared for rapid prototype fabrication of the physical models. The bony models were made using gypsum-based 3D printer and individual templates were fabricated by a selective laser melting machine using commercially pure titanium powder. Pedicle screw trajectory of the bony model, adaptation and stability of the template on the bony model, and screw hole orientation of the template were evaluated using physical models. Custom-made titanium templates with adequate adaptation and stability in addition to proper orientation of the screw holes were sterilised by autoclave and evaluated during surgery. During segmentation, reproducibility of transverse and spinous processes were inferior to the lamina and considered inadequate to select as contact surfaces. A template design with more bone contact area might enhance the stability of the template on the bone but it is susceptible to intervening soft tissue and geometric inaccuracy of the template. In the bony model evaluation, the stability and adaptation of the templates were sufficient with few small round contact surfaces on each lamina; thus, a large contact surface was not necessary. In clinical patients, proper fit for positioning the template was easily found manually during the operation and 141/142 screws were inserted accurately with 1 insignificant pedicle wall breach in AIS patient. This study provides a useful design concept for the development and introduction of custom-fit navigational template for placing pedicle screws easily and safely

The thoracoscopic technic is a minimal surgical approach that minimizes the skin, muscle and ribs trauma without altering the effectiveness of the treatment. This type of surgery has been gaining importance due to its advantages: excellent lighting, visualization and magnification. It offers an acute visual control during manipulation and dissection of delicate structures. We aim to assess the anterior release and the thoracic spine arthrodesis through thoracoscopic approach and measure the effectiveness and security of anterior thoracoscopic instrumentation in an experimental study in pigs. The study was performed on 18 pigs which weighed between 40 and 60 kg. The surgical procedures were conducted at the Hospital Italiano in Buenos Aires. A thoracoscopic surgery was performed as an access to the spine. The quality of the anterior release ranged significantly from cases in which the incision of the common anterior vertebral ligament could not be finished to cases in which more than 75% of the anterolateral disk circumference was released. In the subjective thoracoscopic assessment of the surgeon the screws were placed successfully in all The radiographic assessment confirmed the surgeon’s presumption, all the screws had been placed correctly. The rod presented complications in several cases. The radiographic assessment showed that 40.6% (13 patients) of the disc spaces were pseudoarthrosic or with a delayed union. The macroscopic examination confirmed this finding and raised the number of pseudoarthrosic spaces up to 46.8% (15 patients) revealing 4 discs that still had a nucleus pulposus. The data were reinforced by histologic examination. This histologic cuts were performed using the E & O method. The fibrous ring was clearly identified in the pseudoarthrosic cases as well as the processes of the osteochondral bone formation in its different phases of maturation. It is very important to highlight that in our experience we had found a direct relationship between the quality of the disectomy, the fusion technique and the experience of the surgeon. The surgical technique, the rod placement on the screws needs proper positioning and depth. The radiographic and microscopic examination confirmed that the posterior longitudinal ligaments was not damaged. The thoracoscopic instrumentations in pigs using a rod and screws of third generation is a secure technique. It is essential the development of instrumentation which allows effective thoracoscopic distraction and compression

Introduction: The clinical condition was described as Ankylosing Hyperostosis of the Spine by Forestier (1950. 1. ), was expanded by Resnick (1975) with the Extraspinal Manifestations. 2. What is the nature of this unique formation, asymptomatic in 90% of cases? Several researchers questioned whether the hyperostosis was physiological or pathological. Initially, in 1985 B.M. Rotschild called it a phenomenon . 3. Schlapbach in 1989 found no associated pathological condition . 4. Hutton in his Editorial “Hyperostosis…a State not a Disease“ was doubtful . 5. . In recent personal observations, protection by ossification was recorded in a severe trauma case and in vertebrae weakened by malignant infiltration. Methods: A phylogenetic review of the animal world, followed by an ontogenetic study of mammals/ humans, could assist in a decision regarding the nature (physio-or pathological) of the hyperostosis. Results: The phylogenetic lineage on one side showed the oldest record of hyperostosis in dinosaur (144 million years ago=mya). Ossifications were found in the anterior, lateral, posterior longitudinal ligaments, in C1–C2 transverse ligament. In the other phylogenetic, Hyperostosis was in historic and contemporary mammals. The next step in this study is in the ontogenetic line of the Humans. The oldest skeleton (Ethiopia, 4.5 mya) showed “bridged vertebrae“. The first definite hyperostosis was in the Shanidar skeleton (Iraq, 40–12,000 BCE) with“flowing osteophytes”. In the historic Humans since 9500 BCE, hyperostosis was found in Europeans, Egyptians, Indians (Chile) and Incas. In the Christian era, hyperostosis was present in Roman-British/ Celt populations, Franks, Saxons, British, Swiss and N. Americans. In the 20th C, it is pandemic. Discussion: a. Impressions from the animal world: Paleopathology was established as a scientific branch in 1912 (Ruffer), and exemplified its value in understanding the nature of diseases. Moodie questioned the function of the long spinal “bony rods”, considered them with a protective function. Others . 6. suggested spinal hyperostosis as induced by “mechanical stress”. Shore. 7. (1936) described the spondylitis ossificans ligamentorum as due to mechanical strain. b. Impressions from the Hominid world: The ontogenetic line shows a constant presence of hyperostosis in prehistoric and historic periods. Parallel to human migration from Africa, hyperostosis expanded globally. c. The theory of logical probability: It is postulated that hyperostosis is a condition, as no pathology (other than inflammatory) could have expanded and persisted in many species along millions of years, as it would have been removed by the rules of the Darwinian Selection. Possibly triggered by strain in younger age, functional in the past, it is today an atavistic older age “condition“, with increased osteoblastic activity in connective tissues of ligaments and tendons. At times it is incidentally discovered and is occasionally excessive. Once presented with clinical manifestations, it becomes defined an illness and should be called the Forestier-Resnick syndrome

INTRODUCTION: The clinical condition was described as Ankylosing Hyperostosis of the Spine by Forestier (1950. 1. ), was expanded by Resnick (1975) with the Extraspinal Manifestations. 2. What is the nature of this unique formation, asymptomatic in 90% of cases? Several researchers questioned whether the hyperostosis was physiological or pathological. Initially, in 1985 B.M. Rotschild called it a phenomenon. 3. Schlapbach in 1989 found no associated pathological condition. 4. Hutton in his Editorial “Hyperostosis…a State not a Disease“ was doubtful. 5. . In recent personal observations, protection by ossification was recorded in a severe trauma case and in vertebrae weakened by malignant infiltration. METHODS: A phylogenetic review of the animal world, followed by an ontogenetic study of mammals/ humans, could assist in a decision regarding the nature (physio-or pathological) of the hyperostosis. RESULTS: The phylogenetic lineage on one side showed the oldest record of hyperostosis in dinosaur (144 million years ago=mya). Ossifications were found in the anterior, lateral, posterior longitudinal ligaments, in C1-C2 transverse ligament. In the other phylogenetic, Hyperostosis was in historic and contemporary mammals. The next step in this study is in the ontogenetic line of the Humans. The oldest skeleton (Ethiopia, 4.5 mya) showed “bridged vertebrae“. The first definite hyperostosis was in the Shanidar skeleton (Iraq, 40–12,000 BCE) with “flowing osteophytes”. In the historic Humans since 9500 BCE, hyperostosis was found in Europeans, Egyptians, Indians (Chile) and Incas. In the Christian era, hyperostosis was present in Roman-British/Celt populations, Franks, Saxons, British, Swiss and N. Americans. In the 20th C, it is pandemic. DISCUSSION: (a) . Impressions from the animal world. : Paleo-pathology was established as a scientific branch in 1912 (Ruffer), and exemplified its value in understanding the nature of diseases. Moodie questioned the function of the long spinal “bony rods”, considered them with a protective function. Others. 6. suggested spinal hyperostosis as induced by “mechanical stress”. Shore. 7. (1936) described the spondylitis ossificans ligamentorum as due to mechanical strain. (b . Impressions from the Hominid world. : The ontogenetic line shows a constant presence of hyperostosis in prehistoric and historic periods. Parallel to human migration from Africa, hyperostosis expanded globally. (c) . The theory of logical probability. : It is postulated that hyperostosis is a condition, as no pathology (other than inflammatory) could have expanded and persisted in many species along millions of years, as it would have been removed by the rules of the Darwinian Selection. Possibly triggered by strain in younger age, functional in the past, it is today an atavistic older age “condition“, with increased osteoblastic activity in connective tissues of ligaments and tendons. At times it is incidentally discovered and is occasionally excessive. Once presented with clinical manifestations, it becomes defined an illness and should be called the Forestier-Resnick syndrome

Introduction: Spinal cord injury (SCI) continues to challenge the healthcare and the adjunct social welfare systems. Significant advances have been made in our understanding of the pathological cascade following the initial insult. However, this has yet to be translated into clinically significant treatments and one possible reason for this is that little is known about the actual interaction between the cord and the spinal column at the moment of impact; a factor that is becoming increasingly recognised as important. Burst fractures are a common cause of SCI and are sufficiently well defined to allow significant advances to be made in developing laboratory models of the fracture process. Following on from these advances an in-vitro model of the interaction between the cord and burst fracture fragment was developed and used to perform preliminary experiments to establish those factors that are important in determining the extent of probable cord damage. Methods: A rig was developed that reliably reproduced a range of fragment-cord impact scenarios previously observed in the development of a model of the burst fracture process. In summary, a simulated bone fragment of mass 7.2 g was fired, transversely, at explanted bovine cord (within 3 hours of slaughter) with a velocity of 2.5, 5.0 or 7.5 ms-1. The cords were mounted in a tensile testing machine using a novel clamping system and held at 8 % strain. A surrogate posterior longitudinal ligament (PLL) was included and simulated in three biomechanically relevant conditions: absent, 0 % strain and 14 % strain. The posterior elements were represented by an anatomically correct surrogate. The impacts were recorded by using either a high speed video camera (4500 frames/s) or a series of fine pressure transducers. Results: The fragments were recorded to undergo the same occlusion profile as previously reported in the burst fracture model, except that the cord itself reduced the level of maximum occlusion possible. All tests displayed the fragment recoiling following maximum occlusion. The maximum occlusion and the time to this position were found to be significantly dependent on both the fragment velocity and the condition of the PLL. Similar results were observed for peak pressure. One surprising result was that maximum occlusion or time to this event did not change with or without the cord being encased in the dura mater; a structure that is thought to protect the cord from external impacts. Discussion: The model developed here of the cord-column interaction for the burst fracture produced useful initial insights into the factors that affect the impact on the cord. The PLL has a significant role to play in both reducing the peak pressures and the spreading the energy imparted over a longer period. The model has several areas in which it could be improved and these include 1) the incorporation of the perfusion pressure which tends to hydraulically stiffen the cord and 2) the inclusion of the cerebrospinal fluid, which may operate in unison with the dura in protecting the cord from impacts. Future work includes the incorporation of the CSF into the model, the development of surrogate cords and the generation of computational models using novel programming techniques

Introduction The early clinical results of cervical disc replacement surgery are encouraging but the in vivo kinematics of prostheses remains poorly understood. Two recent published reports suggest that use of a prosthesis with an unconstrained (over normal range of motion) biconvex nucleus (Bryan Cervical Disc® – Medtronic Sofamor Danek, Memphis, TN) can be associated with post-operative segmental kyphosis. This study examines post-operative kyphosis and segmental imbalance following cervical disc replacement using the Bryan Cervical Disc prosthesis and factors which may influence this. In particular, the influence of change in disc space height as a result of surgery was studied. Methods 67 patients underwent prosthetic disc replacement by one of three surgeons (19, 25 and 23 patients, respectively) using the Bryan prosthesis. 46 single, 20 double and 1 triple level were operated. Neutral pre- and post-op erect and intra-operative x-rays were examined manually and using digital image analysis software (Medical Metrics, Inc. Houston, TX). Possible contributing factors to segmental alignment were studied including: pre-op alignment, angle of prosthesis insertion, disc space degeneration and sacrifice of the posterior longitudinal ligament (PLL). Particular attention was given to changes in disc space height and factors which may influence this. Inter- and intra-observer agreement was assessed. Non-parametric tests were used for assessment of categorical and skewed continuous variables. Multivariate linear regression was used to adjust significant correlation coefficients. Significance was set at p< 0.05. Results The median pre-op focal lordosis of +0.5° (range: 21 to −14°, −ve = kyphotic) changed by −1° (+14 to −17°), to post-op: 0° (+11.5 to −16°). There was a significant difference in the median change in focal lordosis for surgeon 1 (−3°) vs. surgeons 2 & 3 (−1°) (p< 0.005) and in the loss of disc space height. Median loss of disc space height for surgeon 1 was 22% vs. 8% for surgeons 2 & 3 (p< 0.002). Correlation co-efficient (Spearman) for change in disc space height vs. change in disc space angulation was 0.67 (p< 0.0001). No single pre- or intra-operative factor was found to clearly correlate with subsequent loss of disc space height apart from a trend towards a weak correlation with the angle of prosthesis insertion (r=0.24, p=0.06). Discussion The median change (loss) in focal lordosis was −1.5° but there was considerable range: from +14° to −17°. Attempts to identify contributing factors suggest that a number may be involved but there did appear to be a highly significant correlation between loss of disc space height following surgery and subsequent focal kyphosis. While the difference in outcomes between Surgeon 1 and Surgeons 2 & 3 is probably not clinically significant, it does suggest that intra-operative factors such as the angle of prosthesis insertion may be important. We are continuing to study these factors

No matter what form of anterior scoliosis instrumentation a spinal surgeon chooses to use it is generally accepted that complete clearance of the intervertebral discs over the levels being instrumented should be undertaken. This improves the flexibility of the curve, potentially enhancing the correction that can be achieved but, perhaps more importantly, reduces the forces that must be exerted on the spine through the instrumentation, particularly at the upper and lower levels. Complete disc clearance may also facilitate intervertebral fusion. The most challenging aspect of disc clearance is removal of the posterior aspect of the annulus and the posterior longitudinal ligament The standard surgical technique involves initial excision of the convex lateral and anterior annulus, followed by the gelatinous nuclear material. This is relatively easily and quickly achieved. However, careful, patient and painstaking piecemeal removal of the posterior annulus is then necessary and this is more time consuming. Care is clearly required to avoid injury to the adjacent dura and neurological structures. Access to the posterior annulus with a ronger becomes more difficult towards the far concave aspect of the disc. Little information is published concerning the time required for standard disc clearance. However, in the author’s experience, and from personal information provided by other surgeons, 30 minutes per level is generally required. Coblation is a relatively new surgical technology by which tissue is removed by vaporisation achieved through the production of an ionized plasma vapour. The depth of vaporisation is very limited and is achieved with virtually no heat production, resulting in minimal thermal damage to adjacent tissue. The author has used coblation in anterior correction of scoliosis, and in his view the technique allows simpler, more controlled and thus ultimately safer clearance of the posterior annulus. Clearance is also achieved more quickly, the time required for each level undertaken being reduced to approximately 15 minutes. The technique involves standard exposure and then excision of the bulk of the disc. The disc must be exposed back to the neural foramen and the convex lateral annulus cleared to this point The anterior annulus is also exposed in the usual manner and excised together with the nuclear material and as much of the posterior annulus that can be easily removed with a ronger. At this point a blunt dissector is introduced into the neural foramen and held in position. Starting at the convex aspect of the posterior annulus and working towards the concave side a ‘Versitor’ coblator wand is then used to remove the posterior annulus, working back to the tip of the dissector . The dissector is not particularly required for safety , the depth of vaporisation being only 0.5 mm, but to establish the posterior extent of the annulus. As this is vaporised the dissector is advanced as necessary . No complications have been observed in the small number of cases undertaken thus far. Current generated by the sodium plasma can result in local neurological stimulation causing muscle twitching, similar to that seen with the use of diathermy, but this has not been associated with any neurological deficit

Aims

Lumbar spinal stenosis (LSS) is a common skeletal system disease that has been partly attributed to genetic variation. However, the correlation between genetic variation and pathological changes in LSS is insufficient, and it is difficult to provide a reference for the early diagnosis and treatment of the disease.

Aims

The presence of facet tropism has been correlated with an elevated susceptibility to lumbar disc pathology. Our objective was to evaluate the impact of facet tropism on chronic lumbosacral discogenic pain through the analysis of clinical data and finite element modelling (FEM).

Purpose of the study. Two patients with very severe thoracolumbar Scheuermann's kyphosis who developed spontaneous bony fusion across the apex of the deformity are presented and their treatment, as well as surgical outcome is discussed. Summary of Background Data. Considerable debate exists regarding the pathogenesis, natural history and treatment of Scheuermann's kyphosis. Surgical correction is indicated in the presence of severe kyphosis which carries the risk of neurological complications, persistent back pain and significant cosmetic deformity. Methods. We reviewed the medical notes and radiographs of 2 adolescent patients with severe thoracolumbar Scheuermann's kyphosis who developed spontaneous posterior and anteroposterior fusion across the apex of the deformity. Results. Patient 1. A male patient aged 17 years and 11 months underwent kyphosis correction when the deformity measured 115o and only corrected to 100o on supine hyperextension radiograph against the bolster; he had a small associated scoliosis. The surgery involved a combined single-stage anterior and posterior spinal arthrodesis T4-L3 with the use of posterior pedicle hook/screw/rod instrumentation and autologous rib graft. The anterior longitudinal ligament was ossified from T10 to L1 with bridging osteophytes extending circumferentially from T11 to T12 at the apex of kyphosis and displacing the major vessels anteriorly. The intervertebral discs from T9 to T12 were very stenotic and immobile. The osteophytes were excised both on the convexity and concavity of the associated thoracolumbar scoliosis. The anterior longitudinal ligament was released and complete discectomies back to the posterior longitudinal ligament were performed from T7 to L1. During the posterior exposure, the spine was found to be spontaneously fused across the apex of the kyphosis from T9 to L1. There were no congenital vertebral anomalies. Extensive posterior apical closing wedge osteotomies were performed from T7 to T12. The fused facets and ossified ligamentum flavum were excised and the spine was mobilised at completion of the anterior and posterior osteotomies. The kyphosis was corrected using a cantilever maneuver from proximal to distal under spinal cord monitoring. Excellent correction to 58o was achieved and maintained at follow-up. Autologous rib graft was used to enhance a solid bony fusion. Patient 2. A female patient aged 18 years and one month underwent kyphosis correction when the deformity measured 115o and only corrected to 86o on supine hyperextension radiograph against the bolster; she had a small thoracolumbar scoliosis. The surgery involved a single-stage posterior spinal arthrodesis T2-L4 with the use of posterior pedicle hook/screw/rod instrumentation and autologous iliac crest bone. The spine was spontaneously fused across the apex of kyphosis from T9 to L1. There were no congenital vertebral anomalies. Extensive posterior apical closing wedge osteotomies were performed from T6 to T12. The fused facets and ossified ligamentum flavum were excised and the spine was mobilised at completion of the osteotomies. The kyphosis was corrected using a cantilever maneuver from proximal to distal under spinal cord monitoring. Excellent correction to 60o was achieved and maintained at follow-up. Autologous iliac crest graft was used to achieve a solid bony fusion. In both patients the preoperative MRI assessed the intraspinal structures but failed to diagnose the solid fusion across the posterior bony elements at the apex of kyphosis. A CT scan with 3D reconstruction would have illustrated the bony anatomy across the kyphosis giving valuable information to assist surgical planning. This is recommended in the presence of rigid thoracolumbar Scheuermann's kyphosis which does not correct in hyperextension, especially if the plain radiograph shows anterior bridging osteophytes. Conclusion. Spontaneous posterior or anteroposterior fusion can occur across the apex of severe thoracolumbar Scheuermann's kyphosis; this should be taken into account when surgical correction is anticipated. The bony ankylosis may represent the natural history of an extreme deformity as an attempt of the spine to auto-stabilise. A combination of factors including a rigid deformity, which limits significantly active movement of the spine, as well as anterior vertebral body wedging with severe adjacent disc stenosis which induces bridging osteophyte formation may result in the development of spontaneous fusion across the apex of the kyphosis either posteriorly or anteroposteriorly. In the presence of an isolated posterior fusion, segmental posterior closing wedge osteotomies with complete excision of the ossified ligamentum flavum and fused facets should mobilise the thoracolumbar spine and allow for kyphosis correction. An additional anterior spinal release including complete discectomies, resection of the anterior longitudinal ligament and osteophytes is required if the bony fusion extends anteroposteriorly. Patients with Scheuermann's kyphosis should be ideally treated at an earlier stage and with a lesser degree of deformity so that this ossification process is prevented

Aims

Degenerative cervical spondylosis (DCS) is a common musculoskeletal disease that encompasses a wide range of progressive degenerative changes and affects all components of the cervical spine. DCS imposes very large social and economic burdens. However, its genetic basis remains elusive.

Aims

The outcome following the development of neurological complications after corrective surgery for scoliosis varies from full recovery to a permanent deficit. This study aimed to assess the prognosis and recovery of major neurological deficits in these patients, and to determine the risk factors for non-recovery, at a minimum follow-up of two years.

To investigate the diagnostic properties of magnetic resonance imaging (MRI) scans in detecting surgically verified disruptions of the cervical intervertebral disc and anterior (ALL) and posterior longitudinal (PLL) ligaments. Data were extracted from the reports of cervical spine MRI scans of patients who subsequently underwent surgical stabilization for presumed instability following disco-ligamentous injuries of the cervical spine. The level and severity of disc, ALL and PLL disruption was compared with surgical findings. Unweighted kappa statistics were used to assess agreement. The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were calculated after findings where dichotomised into complete rupture, yes/no. Sensitivity analyses were performed to account for missing data. The MRI and surgical findings were compared on 31 consecutive patients. The kappa values for intervertebral disc disruption, ALL and PLL disruption were 0.22, 0.25 and 0.31 respectively, indicating fair agreement. Sensitivity, specificity, PPV and NPV are shown in Table 1. The false negative rates for diagnosing complete disruption of the disc, ALL and PLL were 0.18, 0.40 and 0.14 respectively. The ability of cervical MRI scans to detect surgically verified disruptions of the intervertebral disc, ALL and PLL varied depending on the structure examined. In this series, the cervical MRI scan reliably detected disruption of the intervertebral disc disruption and ALL. The false negative rates are of concern and indicate the need for additional investigations to exclude instability in the absence of negative MRI findings

Aims

During revision procedures for aseptic reasons, there remains a suspicion that failure may have been the result of an undetected subclinical infection. However, there is little evidence available in the literature about unexpected positive results in presumed aseptic revision spine surgery. The aims of our study were to estimate the prevalence of unexpected positive culture using sonication and to evaluate clinical characteristics of these patients.

Aims

The purpose of this retrospective study was to investigate the clinical relevance of increased facet joint distraction as a result of anterior cervical decompression and fusion (ACDF) for trauma.