Introduction

Somatosensory evoked potential (SSEP) monitoring allows for assessment of the spinal cord and susceptible structures during complex spinal surgery. It is well validated for the detection of potential neurological injury but little is known of surgeon's responses to an abnormal trace and its effect on neurological outcome. We aimed to investigate this in spinal deformity patients who are particularly vulnerable during their corrective surgery.

Introduction

Evidence suggests that intra-operative spinal cord monitoring is sensitive and specific for detecting potential neurological injury. However, little is known about surgeons' responses to trace changes and the resultant neurological outcome.

To evaluate the current biomechanical and clinical evidence available on the use and effectiveness of lumbar interspinous devices

Literature review

A PubMed search was done using the following key words: interspinous implants, interspinous devices, interspinous spacers, dynamic stabilization, X-stop, Coflex, Wallis, DIAM. The abstracts of all the articles were reviewed. Further critical analysis was done of the relevant articles. Special emphasis was given to those articles pertaining to biomechanical and clinical results.

A total of 50 articles were found, 18 of them also related to the effect of spacers on the biomechanics of the spine. 25 articles were on the X-stop device. However, level I evidence is lacking. Only two prospective randomized controlled trials have been done and these were on the X-Stop device.

Analysis of current evidence suggests a potential beneficial effect of lumbar interspinous spacers in select group of patients. However, further level I evidence is required to justify their widespread use for all the proposed indications. The results of the ongoing trials are keenly awaited.

Non-dysraphic intradural spinal cord lipomas are very rare lesions and the management remains controversial. We present our experience with five cases, review the literature and propose guidelines for their management

The case notes of the patients were retrospectively reviewed. An extensive literature search was done, and the relevant articles were analyzed.

Between January 2004 and April 2009, we operated on five cases of non-dysraphic intradural spinal cord lipomas. The age at presentation ranged from 17 years to 52 years (mean 32.2). Minimum follow up was 6 months and maximum follow up 5 years. All patients underwent decompression with a laminectomy/ laminoplasty and debulking. The dura was primarily closed in one patient.

All patients had regular clinical and radiological follow-up with serial MRI scans.

Neurological improvement was noted in all patients. There was significant residual tumour on the MRI scan in all patients. Guidelines for management were formulated on the basis of our experience and literature review.

The aim of surgery should be adequate decompression with preservation of neural structures. Aggressive debulking should be avoided. Onset of any neurological symptoms/signs, bowel or bladder symptoms or intractable local symptoms should be an indication for surgery.

To describe a modification of the existing technique for C2 translaminar screw fixation that can be used for salvage in difficult cases.

Bilateral crossing C2 laminar screws have recently become popular as an alternative technique for C2 fixation. This technique is particularly useful in patients with anomalous anatomy, as a salvage technique where other modes of fixation have failed or as a primary procedure. However, reported disadvantages of this technique include breach of the dorsal lamina and spinal canal, early hardware failure and difficulty in bone graft placement due to the position of the polyaxial screw heads. To address some of these issues, a modified technique is described. In this technique, the upper part of the spinous process of C2 is removed and the entry point of the screw is in the base of this removed spinous process.

From October 2008 to March 2009, 6 patients underwent insertion of unilateral translaminar screws using our technique. The indications were: basilar invagination(three cases), C1/C2 fracture (two cases), tumour (one case). Age varied from 22 to 81 years (mean 48 years).

All patients had post-operative x-ray and CT scan to assess position of the screws. Mean follow-up was 6 months.

The screw position was satisfactory in all patients. There were no intraoperative or early postoperative complications.

Our modification enables placement of bone graft on the C2 lamina and is also less likely to cause inadvertent cortical breach. Because of these advantages, it is especially suitable for patients with advanced rheumatoid arthritis with destruction of the lateral masses of C2 or as part of a hybrid construct in patients with unilateral high riding vertebral artery. This technique is not suitable for bilateral translaminar screw placement.

Introduction

Atlanto-occipital dislocation is rare and usually fatal. Stabilisation is typically from Occiput to C2, sacrificing atlanto-axial movement. To preserve movement, screw fixation from the articular mass of C1 to the occipital condyle has been described. Amongst other structures, the hypoglossal nerve is at risk. No previous study has addressed the anatomy of the hypoglossal canal in relation to screw trajectory. We aim to identify landmarks to aid safe screw passage into the occipital condyle.

Objective: We prospectively compared the techniques of skip laminectomy and laminoplasty for the treatment of cervical spondolytic myelopathy in terms extent of decompression achieved, axial pain, postoperative range of cervical motion, patient and surgical outcomes.

Methods and results: We studied fifty consecutive patients operated on for cervical spondolytic myelopathy and spinal cord compression as demonstrated on MRI between the levels C3–4 to C6–7. Each patient had a minimum follow-up of two years (2.2 – 4.3 years). Twenty-five patients underwent skip laminectomy and twenty-five patients underwent laminoplasty. Decompression was assessed by pre- and post-operative MRI. Cervical range of motion was assessed by pre- and postoperative flexion and extension radiographs. Patient outcomes were assessed by evaluation of pre-and postoperative neurology and SF12 scores for mental health, physical health and axial pain.

Less blood loss and operative times were found with skip laminectomy. Similar degrees of decompression with both techniques. Significantly improved axial pain scores with skip laminectomy. Significantly improved preservation of range of movement with skip laminectomy.

Conclusion: Skip laminectomy is an effective procedure for reducing the incidence of postoperative morbidities, such as persisting axial pain, and restriction of neck motion often seen after laminoplasty, and provides adequate decompression of the spinal cord as demonstrated on MRI for a minimum follow-up of two years.

Statement of purpose: To profile the neurological lesions associated with scoliosis, evaluate the role of preoperative MRI and determine the proportion of patients requiring surgery for an intradural lesion.

Methods: The records of patients undergoing surgery to treat scoliosis over a 5 year period were reviewed as part of this retrospective single centre study.

Results: 1926 patients underwent 2714 procedures to treat scoliosis. 45 patients from this cohort were referred for an opinion regarding at least one of the following neural axis abnormalities: Syrinx (47%); Chiari malformation and cerebellar ectopia (40%); tethered cord (13%); persistent central canal (9%); diastematomyelia (7%); neurofibromata (7%); syndromes other than neurofibromatosis (7%); tumours (4%) and vascular lesions (2%).

18 patients underwent surgery to treat a neural axis lesion: Foramen magnum decompression (12); cord untethering (4) and the surgical treatment of diastematomyelia (2).

Conclusions: The authors believe their series to be the largest to date.

Preoperative MRI scans should extend from the cranio-cervical junction to the sacrum, reflecting the potential locations of neural axis lesions.

Radiologists present at units treating scoliosis should be able to identify both commonly occurring lesions such syrinx and intradural pathology.

A significant proportion of patients required surgery to treat their neural axis lesions. Centres treating patients with scoliosis should therefore have the necessary facilities to treat not only scoliosis but also its associated intradural spinal lesions.

Ethics approval: None Audit

Interest Statement: None

Introduction: Although there are several accepted methods of surgical treatment for single level cervical radiculopathy, the choice depends on the surgeon’s preference. The techniques may vary in perioperative morbidity, short and long term outcome, but no study so far has analysed their cost-effectiveness. To compare the outcome and cost-effectiveness of four techniques commonly used for degenerative cervical disc pathology.

Methods: We conducted a observational cohort study from two spinal units. Between 1999 and 2004, 60 patients underwent surgery for single level anterior cervical disc pathology. Out of this 30 patients underwent their surgery in centre A the other 30 in centre B. Centre A used two ACDF techniques-group 1- plate and tricortical graft, group 2- plate, cage and bone substitute (BCP granules). Centre B used two other techniques- group 3- cage alone with autologous locally harvested graft, group 4- disc arthroplasty. We had 15 patients in each of the above four groups. Operating time, blood loss, duration of stay, donor site morbidity, analgesia requirements, and total cost incurred per patient were recorded. All patients were followed up at 6 weeks, 3 months, 6 months, 1 year and 2 years. The clinical outcome and pain assessment were done using the SF12 and VAS.

Results: The three Fusion groups had a similar radiological outcome. With appropriate statistical analysis, there were no differences in physical and mental domains of the SF12 or pain scores between the groups. The average operative time in the group 1 was 160 minutes, group 2 was 100 minutes, group 3 was 90 minutes and group 4 was 105 minutes. Average blood loss was minimal in all groups. The average hospital stay was of 5, 2.7, 2.5, 2 days for groups 1–4 respectively. The average total cost per patient in the group 1 (surgery+stay+plate) was £2790, group 2 (surgery+stay+plate+cage+BCP) was £2400, group 3 (surgery+stay+cage) was £1900, and group 4(surgery+stay+disc implant) was £2350.

Conclusion: All the techniques gave similarly satisfactory clinical outcomes but using cages alone could be more cost-effective than using iliac crest auto-graft for fusion. The disc arthroplasty was comparable to cage with bone substitute and plate in terms of outcome and may giev the surgeon an alternative choice in patients who are not keen on/ unfit for fusion.

AIM: To compare the outcomes between two different surgical techniques for cervical myelopathy (skip laminectomy vs laminoplasty).

METHODS: Cervical skip laminectomy is a new technique described by Japanese surgeons in 2000. The advantage of this procedure over the other conventional techniques is it addresses multilevel problem in a least traumatic way without need for instrumentation.

We are comparing the above two techniques with 25 patients in each group operated by 3 surgeons. The first group had conventional laminoplasty and the second group underwent the skip laminectomy. The groups were comparable in age, sex, pathology and clinical presentation. Both these group had clinical outcome measurements using SF 12 questionnaires, pre and postoperative clinical assessment with standard tools performed by independent surgeon and a specialist spinal physiotherapist. We also routinely performed pre and postoperative MRI scans to assess the adequacy of decompression.

RESULTS & CONCLUSION: There was no significant difference in the outcome of these patients in terms of the operative technique, hospital stay, clinical and radiological outcome. However skip laminectomy is relatively a easier procedure to perform, while the laminoplasty does need instrumentation.

Introduction: There is growing interest in Health Related Quality of Life (HRQL) questionnaires to quantitate the impact of a variety of diseases and their treatments. The Short Form-36 (SF3) is a comprehensive measure of health status, consisting of 36 questions related to Physical (PCS) and Mental Component Summary (MCS).1 An abbreviated version of SF36, the SF12 has been described.2 We report on the use of SF12 and SF36 to assess the impact of surgery in patients with cervical spondylotic myelopathy (CSM).

Methods: In this prospective study, patients undergoing anterior or posterior decompressive surgery self completed the SF36 questionnaire pre-operatively and at 6 months post-operatively. The data from the SF36 is categorised into 8 scales: physical functioning (PF), physical role (PR), bodily pain (BP), general health (GH), vitality (VT), social functioning (SF), emotional role (ER) and mental health (MH).1 Each scale is scored on a 0 (maximum disability) to 100 (no disability) metric. These 8 scales are reduced to a Physical (PCS) and Mental Component Summary (MCS).1 SF12 utilises only 12 questions of the 8 scales of the SF36.2 We compared the validity, reliability and sensitivity to change in CSM patients.

Results: We studied 105 patients with a median age of 58. Post-operatively, there were improvements in the PCS components of both the SF36 (40 ± 2 to 54 ± 2) and SF12 (34 ± 2 to 48 ± 3) (p< 0.0001; Wilcoxon Signed Ranks test) and MCS component of SF36 (48 ± 2 to 63 ± 2) and SF12 (43 ± 2 to 59 ± 2) (p< 0.001). There were linear relationships between the SF36 and SF12.

Conclusions: Both the SF12 and SF36 scales are valid and sensitive to changes in CSM patients, undergoing decompressive surgery. Despite its abbreviated nature, SF12 appears to be an adequate substitute for SF36 and its brevity should increase its attractiveness to both the clinicians and patients.

Introduction: Atlanto-Occipital dislocation is rare and usually fatal. Stabilisation is typically from Occiput to C2; sacrificing atlantoaxial movement. To preserve movement, screw fixation from the articular mass of C1 to the occipital condyle has been described. Amongst other structures, the hypoglossal nerve is at risk. No previous study has addressed the anatomy of the hypoglossal canal in relation to screw trajectory. We aim to identify landmarks to aid safe screw passage into the occipital condyle.

Methods: 20 dry skulls provided 40 hypoglossal canals (HCs) and 40 occipital condyles (OCs). No distinction was made between sex, race or age. 9 parameters were measured for each HC, and relation to skull base was noted.

Results: The mean length of the HC was 10mm (range 8 to 14). The extra-cranial foramen of the HC is located lateral to the intra-cranial foramen (30° range 19 to 45). 19 out of 20 skulls had HCs with intra-cranial foramina more caudal than their extra-cranial foramina, ie the HC angled cranially (22° range 7 to 51). 36 of 40 OCs were found to be wholly inferior to the rim of the foramen magnum, with 4 (in 2 skulls) whose bodies lay largely below, but extended above, this landmark. Every single HC studied was situated, in its entirety, superior to the rim of the foramen magnum.

Conclusions: The trajectory of the hypoglossal canal from its intra-cranial foramen is antero-supero-lateral. It is situated, in its entirety, superior to the rim of the foramen magnum. The thickest portion of the occipital condyle is antero-medial. Screw passage from posterior through the C1 articular mass ought to aim for the anterior, superior, medial quadrant of the occipital condyle, and should not pass cranial to the rim of the Foramen Magnum in order to minimise the risk to the Hypoglossal Nerve.

46 Sacral chordoma patients treated between 1987 and 2004 are reviewed. The importance of early diagnosis, adequate surgical margin and post operative radiotherapy for optimum outcome and survival is stressed.

There were 33 male and 13 female patients, with a mean age of 61 years (38–73 years). The surgical approach depended on the level and extent of the lesion, with an anteroposterior approach used in 23 and posterior approach in 17 patients. 20 had partial sacrectomy, 17 had subtotal sacrectomy and 3 underwent total sacrectomy. 6 patients were deemed inoperable and received palliative therapy. 14 patients received radiotherapy post-operatively. The length of average follow up was 4.27 years (range 2–15.7 years).

Low back pain was the most common presenting symptom (80%), and 50% patients had a palpable mass. The mean duration of symptoms prior to diagnosis was 2 years (range 1 month–10 years). Examination revealed a palpable mass in 7 both externally and on rectal examination. 10 had a palpable mass on rectal examination but not externally. 2 patients presented with multiple metastases and another 2 with widespread local disease. Excision was complete in 23 patients and incomplete in 17. Histology revealed dedifferentiation in 4. Complete excision margin was achieved in 69.6% through combined approach and 52.9% through posterior approach only. 24 patients (52%) had local recurrence. Without adjuvant radiotherapy the mean disease free period following complete excision was 3.5 years, compared to 0.9 years following incomplete excision. Adjuvant radiotherapy extended the mean disease free period following incomplete excision to 1.8 years.

The authors conclude that an early diagnosis and careful examination is important. Wide excision remains the mainstay of treatment. If excision is incomplete radiotherapy increases the disease free period although local recurrence is inevitable. The use of a combined approach increases the likelihood of complete excision.

Aim: To compare the outcomes between two different surgical techniques for cervical myelopathy (skip laminectomy vs laminoplasty).

Methods: Cervical skip laminectomy is a new technique described by Japanese surgeons in 2000. The advantage of this procedure over the other conventional techniques is it addresses multilevel problem in a least traumatic way without need for instrumentation.

We are comparing the above two techniques with 25 patients in each group operated by 3 surgeons. The first group had conventional laminoplasty and the second group underwent the skip laminectomy. The groups were comparable in age, sex, pathology and clinical presentation. Both these group had clinical outcome measurements using SF 12 questionnaires, pre and postoperative clinical assessment with standard tools performed by independent surgeon and a specialist spinal physiotherapist. We also routinely performed pre and postoperative MRI scans to assess the adequacy of decompression.

Results and Conclusion: here was no significant difference in the outcome of these patients in terms of the operative technique, hospital stay, clinical and radiological outcome. However skip laminectomy is relatively a easier procedure to perform, while the laminoplasty does need instrumentation.

Background: The phenomenon of heterotopic ossification (HO) is a well-known complication of joint replacement surgery. However, the clinical associations and effects of HO in cervical arthroplasty are unclear. This study investigates the incidence of HO in cervical disc replacement, identifies potential associated risk factors, and assesses the relationship of HO with clinical outcomes.

Method: The patient population (n=90; 39 men, 51 women; mean age 45 years; range 26–79 yr; standard deviation, 9.8 yr) was acquired from the original multi-center, prospective, observational Bryan Disc Study by the European Consortium. The presence of HO was defined in accordance with the McAfee classification based on cervical lateral x-rays at 12 months post surgery and interpreted by an independent neurosurgeon and a radiologist. Secondary outcome measurements included Odom’s criteria and the Medical Outcomes Study Short-Form 36-Item Health Survey.

Results: 16 out of the total 90 patients (17.8%) experienced HO. 6 patients (6.7%) experienced Grade 3 and 4 HO. 10 patients’ (11%) artificial discs demonstrated movement of less than 2 degrees on flexion and extension cervical x-ray at 12 months post-operatively. 4 of these patients had HO of Grade 3 or 4. Male sex ([chi]² = 4.1; P = 0.0407) and older patients (P = 0.023; odds ratio = 1.10; 95% confidence interval = 1.01–1.19) were associated with development of HO.

Discussion: HO is known to restrict movement of large joint and lumbar disc replacements. Our study demonstrates male sex and older age as potential risk factors in development of HO after cervical disc arthroplasty. There is a strong association between HO and subsequent loss of movement of implanted cervical artificial discs. Failure to preserve motion may expedite the onset of symptomatic adjacent segment level disease making this an important complication requiring further investigation. Grade 3 or 4 HO limited movement in 4.4% of patients.

Aim: The purpose of this study was to evaluate the extent of neurological deficit following excision of spinal neurofibromas.

Methods: Retrospective case series, combined with contemporary neurological examination and outcome questionnaires.

Results: 46 patients (26 males, 20 females) with a mean age of 46 between the years of 1985 – 2005. The incidence of neurological deficit subsequent to nerve sectioning to remove the tumour was 28/46 (60.9%) in the acute period. In the long term this reduced to 28%.

Conclusions: Despite the sectioning of nerves during surgery motor or sensory deficit was surprisingly rare. It was mainly sensory and recovered with time. This is presumably due to neural plasticity and dermatomal overlap. These results provide useful information for surgeons to counsel their patients preoperatively.

Purpose: To report the genetic correlation of familial chordoma, a rare tumour of embryonic notochordal remnant.

Method: We present two patients with a family history of chordoma. Both patients had surgery at our unit, one for a clival and one for a sacral tumour. These two cases comprise 1.14% (2 out of total 175 chordoma cases) of our unit’s surgical experience with chordoma (79 cases involving craniocervical junction, 4 cases involving thoracolumbar spine, 92 cases involving sacral region) over the period of 15 years (1990– 2005). Patient1 had clival chordoma and Patient2 had sacral chordoma. Both the patients had excision of the tumour followed by postoperative radiotherapy and annual follow up. There was no recurrence eight years later in Patient 1 and Patient 2 died three years after the surgery.

Results: Patient 1 had ten other family members affected by chordoma (mostly clival) and Patient 2 had two other family members affected by clival chordoma. Genetic analysis for the Patient 1 and of her relatives (National Cancer Institute, Bethesda) showed that there was loss of heterozygosity on chromosome 7q 33. None of the affected members of the Patient 2 were alive to do the genetic study.

A literature search on genetic studies was performed using the key term as familial chordoma and following studies have been found-

Kelly et al- the study had 10 affected members and showed linkage to chromosome 7q 33.

Conclusion : Familial chordoma is a very rare tumour. Further genetic studies will hopefully reveal valuable insight into the pathogenesis and possible therapeutic measures of this tumour.

Purpose: To report the importance of early diagnosis, adequate surgical margin and postoperative radiotherapy for optimum outcome and survival.

Study Design: A retrospective review of 46 sacral chordoma patients treated between 1987 and 2004.

Methods: There were 33 male and 13 female patients, with mean age of 61 years (38 to 73 year). The surgical approach depended on the level and extent of the lesion, with an anteroposterior approach used in 23 and posterior approach in 17 patients. 20 had partial sacrectomy, 17 had subtotal sacrectomy and 3 underwent total sacrectomy. 6 patients were deemed inoperable and received palliative therapy. 14 patients received radiotherapy postoperatively. The length of average follow up was 4.27 years (range 2–15.7 years).

Results: Low back pain was the most common presenting symptom (80%), and 50% patients had a palpable mass. The mean duration of symptoms prior to diagnosis was 2 years (range 1 month–10 years). Examination revealed a palpable mass in 7 both externally and on rectal examination. 10 had palpable mass on rectal examination but not externally. 2 patients presented with multiple metastases and another 2 with widespread local disease.

Excision was complete in 23 patients and incomplete in 17. Histology revealed dedifferentiation in 4. Complete excision margin was achieved in 69.6% through combined approach and 52.9% through posterior approach only. 24 patients (52%) had local recurrence. Without adjuvant radiotherapy the mean disease-free period following complete excision was 3.5 years, compared to 0.9 years following incomplete excision. Adjuvant radiotherapy extended the mean disease-free period following incomplete excision to 1.8 years.

Conclusion: An early diagnosis and careful examination is important. Wide excision remains the mainstay of treatment. If excision is incomplete radiotherapy increases the disease free period although local recurrence is inevitable. Use of combined approach increases the likelihood of complete excision.