The multimodal management of canal stenosis is increasing, and inhibitors of central sensitization are playing a crucial role in central sensitization processes. Pregabalin and gabapentin are antiepileptic drugs that reduce presynaptic excitability. The objective of this study was to investigate whether the use of pregabalin and gabapentin is effective in the symptomatic management of canal stenosis. A literature search was conducted in four databases. The inclusion criteria were studies that compared pregabalin or gabapentin with a control group in lumbar canal stenosis. Randomized clinical trials and a comparative retrospective cohort study were included. The main clinical endpoints were VAS/NRS, ODI, and RDQ (Roland Morris Disability Questionnaire) at 2, 4, 8 weeks, and 3 months, adverse events, and walking distance were also collected. Data were combined using Review Manager 5.4 software. Six studies and 392 patients were included. The mean age was 60.25. No significant differences were observed in VAS at 2, 4, and 8 weeks: (MD: 0.23; 95% CI: −0.63-1.09), (MD: −0.04; 95% CI: −0.64 to −0.57), and (MD: −0.6; 95% CI: −1.22 to 0.02). Significant differences were observed in favor of pregabalin with respect to VAS at three months: (MD: −2.97; 95% CI: −3.43 to −2.51). No significant differences were observed in ODI (MD: −3.47; 95% CI: −7.15 to −0.21). Adverse events were significantly higher in the pregabalin/gabapentin group (OR 5.88, 95%CI 1.28-27.05). Walking distance and RDQ could not be compared, although the results were controversial. Gabapentinoids have not been shown to be superior to other drugs used in the treatment of LSS or to placebo. However, they have shown a higher incidence of adverse effects, improved results in VAS at 3 months, and a slight improvement in ambulation at 4 months in combination with NSAIDs compared to NSAIDs in monotherapy

The October 2023 Spine Roundup³⁶⁰ 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.

Background. Gore and Nadkarni described a ‘Gore sign’ of reproducing radiating leg pain by palpation of distal nerve root endings in the foot for L5 and S1 nerve roots in lumbar radiculopathy due to disc prolapse. Purpose. This sign was explored and observation of symptoms recorded. Results. There were 31 patients, 20 females and 11 males, aged 25 to 76 years. 13 patients had acute disc prolapse, 14 had lumbar canal stenosis, 3 had annular tears and one had a facet cyst. Radiating leg pain was reproduced in all patients by palpation of distal nerve root endings and was immediately relieved by local anaesthetic injection around distal nerve root endings in all patients (second part of Gore test). New clinical signs were observed which have not been described before:. Back pain was reproduced in 21 patients. L4 nerve root pain was reproduced in 13 patients by palpation of the proximal tibia. Crossed leg pain was reproduced in 5 patients. Reproduction of pain by palpation of more than one distal nerve root ending was observed in 16 patients. Cessation of radiating leg pain by palpation of distal nerve root endings in two patients. These test were positive in patients with varied pathology producing radiculopathy, not just disc prolapse. Conclusion. Provocative nerve root tension signs can be difficult in severe pain. The tests described above can be performed without having to move the patient's lower limb. These observations open up discussion on the mechanism of radiculopathy and new ways of treatment. Conflicts of interest: None. Sources of funding: None

Background. Acute lumbar radiculopathy is a very painful condition sometimes requiring admission for strong analgesia. Purpose. To evaluate the efficacy of distal nerve root blocks as an outpatient procedure for immediate pain relief. Methods. Local anaesthetic was injected in the distal nerve root areas of the leg and foot in the clinic in patients with lumbar radiculopathy who consented to the procedure. Results. There were 29 patients, 18 females and 11 males, aged 25 to 76 years. 13 patients had acute lumbar disc prolapse, 11 had lumbar canal stenosis, 2 had annular tears and one a facet joint cyst. The VAS pain scores ranged from 3 to 11 (patient's description), with an average VAS score of 7.5. The improvement in VAS scores was between 2 and 9 with average improvement of 6. 19 patients had associated back pain which improved in 14. Walking improved in all 29 patients. Pain relief was immediate in all patients. This lasted from 30 min to 11 days with one patient having no recurrence. 27 patients had at least 24 hours pain relief. All patients could be sent home immediately after the procedure. 12 patients had recent onset of foot weakness which improved one MRC grade immediately after the injection. The analgesic effect was most significant in acute disc prolapse. There were no complications. Conclusion. This technique is simple and would be valuable in the acute setting to provide immediate pain relief allowing immediate discharge from accident and emergency. Conflicts of interest: None. Sources of funding: None

Aims

Patients may present with concurrent symptomatic osteoarthritis (OA) of the hip and degenerative disorders of the lumbar spine, with surgical treatment being indicated for both. Whether arthroplasty of the hip or spinal surgery should be performed first remains uncertain.

Aims

Instability continues to be a troublesome complication after total hip arthroplasty (THA). Patient-related risk factors associated with a higher dislocation risk include the preoperative diagnosis, an age of 75 years or older, high body mass index (BMI), a history of alcohol abuse, and neurodegenerative diseases. The goal of this study was to assess the dislocation rate, radiographic outcomes, and complications of patients stratified as high-risk for dislocation who received a dual mobility (DM) bearing in a primary THA at a minimum follow-up of two years.

Aims

The aims of this study were to describe the prevalence of previous lumbar surgery in patients who undergo total hip arthroplasty (THA) and to investigate their patient-reported outcomes (PROMs) one year post-operatively.

Background. Unexplained pain is one of the most common complications after Oxford UKAs. We have retrospectively reviewed the patients who underwent Oxford UKAs and investigated those patients with prolonged pain and found that many of these patients had strong tenderness over the Hunter canal and they were well treated with Hunter canal block or administration of Pregabalin. We have checked the details of these prolonged pain and key to the treatment will be discussed. Methods. Between May 2006 and September 2014 we have performed 316 Oxford UKAs. There were 47 males and 269 females with average age of 70.4 years old (46–90). The patients were followed up for at least 6 months (6 months to 8.0 years, mean follow-up period of 3.1 years). The patients were examined both clinically and radiologically. Result. There were 30 knees (9.5%) that showed prolonged pain continuing more than 3 month after the operation(Fig.1). Of these 30 knees, 17 knees had strong tenderness over the Hunter canal, and many patients had numbness and radiating pain toward medial side of the lower extremities. They were diagnosed as having Hunter canal syndrome clinically. Of these 17 knees 5 were treated successfully with Hunter canal block with Lidocaine. Remaining 12 knees were treated with Pregabalin or with Tramadol. All but 1 knee, pain disappeared within 3 months after starting the treatment as we stated. There were 3 cases that were finally diagnosed as having lumbar canal stenosis and L3 root block was effective. For the 10 knees not diagnosed as having Hunter canal syndrome without any tenderness over the Hunter canal, the pain disappeared spontaneously in 2 knees, and the pain disappeared with administration of Pregabalin or Tramadol in 6 knees. Two patients didn't respond to any treatment, they were referred to psychiatrist and diagnosed as having mental problems. There was no abnormal radiolucency, which suggested loosening of the component. As a result, true unexplained pain that continued more than a year was only 1. Discussion. 17 knees out of 30 unexplained pain knees after Oxford UKAs had strong tenderness over the Hunter canal, and the pain disappeared after the saphenous nerve block or adminestration of Pregabalin except for 1 knee. Patients without the diagnosis of Hunter canal syndrome also responded well to either Pregabalin or Tramadol. The pain continuing for more than 3 months after Oxford UKA is usually self-limited and well treated conservatively. With these results, when you see the prolonged pain after Oxford UKA, we strongly recommend just wait and see by conservative treatment with Pregabalin, Tramadol or saphenous nerve block, and do not revise the implant

Aims

The aim of this study was to evaluate the time course of changes in parameters of diffusion tensor imaging (DTI) such as fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in patients with symptomatic lumbar disc herniation. We also investigated the correlation between the severity of neurological symptoms and these parameters.

The aim of this study was to evaluate the feasibility of using the intact S1 nerve root as a donor nerve to repair an avulsion of the contralateral lumbosacral plexus. Two cohorts of patients were recruited. In cohort 1, the L4–S4 nerve roots of 15 patients with a unilateral fracture of the sacrum and sacral nerve injury were stimulated during surgery to establish the precise functional distribution of the S1 nerve root and its proportional contribution to individual muscles. In cohort 2, the contralateral uninjured S1 nerve root of six patients with a unilateral lumbosacral plexus avulsion was transected extradurally and used with a 25 cm segment of the common peroneal nerve from the injured leg to reconstruct the avulsed plexus.

The results from cohort 1 showed that the innervation of S1 in each muscle can be compensated for by L4, L5, S2 and S3. Numbness in the toes and a reduction in strength were found after surgery in cohort 2, but these symptoms gradually disappeared and strength recovered. The results of electrophysiological studies of the donor limb were generally normal.

Severing the S1 nerve root does not appear to damage the healthy limb as far as clinical assessment and electrophysiological testing can determine. Consequently, the S1 nerve can be considered to be a suitable donor nerve for reconstruction of an avulsed contralateral lumbosacral plexus.

Cite this article: Bone Joint J 2015; 97-B:358–65.

Summary Statement. Tandem stenosis is a prevalent condition in an Asian population with the narrowest cervical canal diameters and risk factors include advanced age and increased levels of lumbar canal stenosis. Introduction. Tandem spinal stenosis (TSS) is defined as patient with concomitant spinal canal stenosis found in both cervical (C) and lumbar (L) spinal region. Few studies have reported the incidence of TSS is ranged from 5–25%, but these are all noncomparative, small cohort studies. To the best of author knowledge this is the 1st study aims to compare the prevalence of TSS and its risk factors of development in a large multiracial Asian population. Methods. A retrospective review of all mid-sagittal T2MRI whole spine image was carried out at a University hospital in year 2007. Patients with spinal tumour, fracture and congenital stenosis were excluded. Spinal stenosis was defined as canal diameter of ≤10mm, measured from the posterior cervical vertebral/disc wall to anterior surface of the corresponding lamina. Patients were divided into 4 groups, no stenosis(NS), lumbar stenosis only(LS), cervical stenosis only(CS) and TSS. Patients’ demographics, race, co-morbidities and lumbar radiological report data were examined. Potential risk factors for the development of TSS were analyzed using SPSS software. Results. 926 (479 male, 447 female) patients with average age 50 (20–96) yrs were studied. Cervical canal diameters (mm) in TSS patients were the narrowest among the 4groups with C2/3 disc: 11.6, C3/4: 9.7, C4/5: 9.4, C5/6: 8.9, C6/7: 10.0 and C7T1: 11.4mm. The incidence of TSS was 26.2%. The prevalence of TSS in Chinese was 30.7%, Indian 12.5%, Malay 22.5%. The TSS prevalence in patients with 1 level lumbar canal stenosis was 12.5%, 2 levels lumbar stenosis was 6.4% and 3 levels was 4.1%. Multivariate analysis showed patients aged between 40–59 yrs (p=0.000, Exp(B):5.8, 95%CI 2.8–12.0), aged > 60yrs (p=0.000, Exp(B): 10.5, 95%CI 4.8–22.9), Chinese race (p=0.008, Exp(B): 2.5, 95%CI 1.3–4.9), patients with 1 level lumbar stenosis (p=0.000, Exp(B): 63.3, 95%CI 29.2–137.3), 2 levels lumbar stenosis (p=0.000, Exp(B): 67.7, 95%CI 29.4–155.7) and 3 levels lumbar stenosis (p=0.000, Exp(B): 106.6, 95%CI 43.6–260.5) are statistical significant risk factors for TSS development. Conclusion. The incidence of TSS was 26.2%. TSS patients have the narrowest cervical canal measurements among the studied groups. The prevalence of TSS in Chinese is the highest (30.7%). Patients advancing in age or have increased levels of lumbar canal stenosis are at risk of developing TSS

Little information is available about the incidence and outcome of incidental dural tears associated with microendoscopic lumbar decompressive surgery. We prospectively examined the incidence of dural tears and their influence on the outcome six months post-operatively in 555 consecutive patients (mean age 47.4 years (13 to 89)) who underwent this form of surgery. The incidence of dural tears was 5.05% (28/555). The risk factors were the age of the patient and the procedure of bilateral decompression via a unilateral approach. The rate of recovery of the Japanese Orthopaedic Association score in patients with dural tears was significantly lower than that in those without a tear (77.7% vs 87.6%; p < 0.02), although there were no significant differences in the improvement of the Oswestry Disability Index between the two groups. Most dural tears were small, managed by taking adequate care of symptoms of low cerebrospinal fluid pressure, and did not require direct dural repair. Routine MRI scans were undertaken six months post-operatively; four patients with a dural tear had recurrent or residual disc herniation and two had further stenosis, possibly because the dural tear prevented adequate decompression and removal of the fragments of disc during surgery; as yet, none of these patients have undergone further surgery.

Cite this article: Bone Joint J 2014;96-B:641–5.

Study Purpose. To examine the presence of radicular pain and its relationship to the degree of lumbar nerve root compression in patients with a degenerative lumbar spine condition about to undergo surgery for either lumbar disc prolapse or lumbar canal stenosis. Background. The pathophysiology underlying radicular pain is not completely understood but it is thought that nerve root compression is a key factor and from a surgical perspective, decompressing the nerve root is considered to be the key therapeutic step. However, despite often severe root compression in patients with lumbar stenosis, radicular pain is not a typical feature. Methods. Thirty-nine pre-surgical patients with either lumbar disc prolapse or lumbar canal stenosis were studied using the Standardised Evaluation of Pain (StEP), a clinical assessment tool known to predict with a high degree of sensitivity and specificity the presence or absence of lumbar radicular pain. A nerve root compression score was given from lumbar MRI for each patient by a neuroradiologist blinded to the patients history. Results. The StEP assessment tool was able to distinguish the presence or absence of radicular pain with high sensitivity and specificity. This correlated well with the pre-operative diagnosis of disc prolapse or canal stenosis. The relationship between radicular pain and nerve root compression was less clear and will be discussed. Conclusion. This study confirms StEP as a useful bedside tool for identifying the presence of radicular pain in patients with a degenerative lumbar spine condition. Nerve root compression per se does not necessarily produce radicular pain. Conflicts of Interest. None. Source of Funding. None. This study has not been published or presented at a previous meeting

Patients with neurogenic claudication from lumbar canal stenosis non-responsive to non-surgical treatment are usually managed with spinal decompression with or without fusion. Flexion at stenotic segments relieves symptoms by increasing canal cross-sectional area, intervertebral foraminal height. Interspinous spacers work by causing flexion at the treated segement. We used COFLEX¯ [Paradigm Spine] a titanium interspinous spacer along with interlaminar decompression where indicated. To compare the clinical and radiological results of patients undergoing interlaminar decompression with or without use of COFLEX¯. Pre and post-operative assessment and comparison of clinical outcomes of Oswestry disability index(ODI), Visual analog Scale(VAS), Short Form-36(SF-36) and radiological outcomes of disc heights of operated and adjacent levels, intervertebral foraminal heights, sagittal angles of the operated segment. All consecutive patients undergoing spinal decompression at one or more levels from Jan to Dec 2008 were included. Patients with clinically symptomatic back pain for a duration longer than claudication pain were offered interspinous spacer at L4/5 level or above. In first group(n-20), patients were treated with inter-laminar decompression and COFLEX¯ with a standard posterior approach. In second group(n-25) inter-laminar decompression for the involved segment was performed. All patients are on follow-up. Clinical and radiological outcomes were compared at 6 months and 1 year. Statistically significant(p<0.001) improvements in ODI, VAS(back), VAS(leg) and SF-36 in patients in whom COFLEX¯ was used. Radiological parameters also showed significant improvements(p<0.05). Use of COFLEX¯ spacer is justified in patients with symptomatic disc degeneration with neurogenic claudication when treated operatively

We retrospectively examined the prevalence and natural history of asymptomatic lumbar canal stenosis in patients treated surgically for cervical compressive myelopathy in order to assess the influence of latent lumbar canal stenosis on the recovery after surgery. Of 214 patients who had undergone cervical laminoplasty for cervical myelopathy, we identified 69 (32%) with myelographically documented lumbar canal stenosis. Of these, 28 (13%) patients with symptomatic lumbar canal stenosis underwent simultaneous cervical and lumbar decompression. Of the remaining 41 (19%) patients with asymptomatic lumbar canal stenosis who underwent only cervical surgery, 39 were followed up for ≥ 1 year (mean 4.9 years (1 to 12)) and were included in the analysis (study group). Patients without myelographic evidence of lumbar canal stenosis, who had been followed up for ≥ 1 year after the cervical surgery, served as controls (135 patients; mean follow-up period 6.5 years (1 to 17)). Among the 39 patients with asymptomatic lumbar canal stenosis, seven had lumbar-related leg symptoms after the cervical surgery. Kaplan–Meier analysis showed that 89.6% (95% confidence interval (CI) 75.3 to 96.0) and 76.7% (95% CI 53.7 to 90.3) of the patients with asymptomatic lumbar canal stenosis were free from leg symptoms for three and five years, respectively. There were no significant differences between the study and control groups in the recovery rate measured by the Japanese Orthopaedic Association score or improvement in the Nurick score at one year after surgery or at the final follow-up. These results suggest that latent lumbar canal stenosis does not influence recovery following surgery for cervical myelopathy; moreover, prophylactic lumbar decompression does not appear to be warranted as a routine procedure for coexistent asymptomatic lumbar canal stenosis in patients with cervical myelopathy, when planning cervical surgery

Purpose of the study: It is currently accepted (particularly since the work by Katz et al.) that a number of factors can potentially influence the functional outcome obtained after surgical treatment of lumbar canal stenosis (LCS). Among these factors are comorbid conditions and the notion of perceived health appear to be predominant. Little work has however been focused on the influence of these same factors on the qualitative and quantitative expression of functional impairment expressed by patients before their treatment. This possible link might have an intrinsic impact on the assessment of the outcome obtained after medical or surgical treatment of LCS. We wanted to examine this question. Material and methods: Two hundred twenty patients referred to our orthopaedic surgery consultations were included in this prospective observation study, irrespective of the type f treatment eventually proposed (medical or surgical) or the type of lumbar stenosis. Patients who had had prior spinal surgery and those treated for LCS due to spinal deformity were excluded. The degree of the functional symptoms was determined with the SF36 and a self-administered questionnaire specifically designed and validated for the evaluation of LCS. Comorbidity factors were studied individually and with the following scores: the ASA score, the FCI (Functional Comorbidity Index), the CIRS (Cumulative Illness Rating Scale, and the ICED (Index of co-existent Diseases). Univariate and multivariate analysis was used to search for correlations between expressed functional impairment and comorbid factors. Results: Expression of a functional impairment was significantly associated with a high number of comorbidity factors. This correlation was tighter when there was no additional compressive discal factor and when the functional neurological symptoms were longstanding. The type of comorbid factor analysed did not have an impact on these results. Conclusion: The presence of comorbid factors is significantly associated with more severe expression of functional impairment related to LCS. This effect could also influence the functional outcome after treatment of LCS and should be taken into consideration

Background: X stop interspinous decompression device has been used effectively in symptomatic patients with lumbar canal stenosis. The positional MRI scanner images patients in the erect weight bearing position and is used here to evaluate the efficacy of the X stop in maintaining increase in dural sac and foraminal areas. Aim: To assess the clinical effectiveness of X stop in patients with lumbar canal stenosis and measure its effect in decompressing the spinal canal two years postoperatively. Design: Prospective Observational Study. Methods: Clinical outcome was assessed by ZCQ, VAS, ODI and SF36 questionnaires. Clinical and radiological outcomes were measured preoperatively and at 2 years. Foraminal area was measured in flexion and extension whereas dural sac area was measured in erect, neutral, flexion and extension. Osiris 4.17 software program was used for the measurements. The data was analysed using paired t test on SPSS ver.15.01. Results: With ZCQ overall 57% of patients had clinically significant improvement at 24 months. The mean ODI and VAS scores showed improvement. The SF-36 improved in four domains. Radiologically we noted increase in mean dural sac area in all positions. There was a small increase in foraminal areas and statistically significant increase in dural sac areas at 24 months. Conclusion: The X stop device remains clinically effective at the end of 2 years. It is a relatively less invasive procedure without major complications and can be performed as a day case procedure. X stop maintains increase in dural sac and foraminal areas at 24 months postoperatively

Introduction: Thickened ligamentum flavum (LF) is a major contributor to the clinical syndrome of lumbar canal stenosis (LCS). The patho-mechanisms responsible for this phenomenon remain unclear. Cysts adjacent to facet joints (FJ) in the spine are regarded as rare entities that may uncommonly contribute to LCS. Inaccurate pathological interpretation and unawareness of a key anatomical feature has generated erratic terminology and confusion about their origin. Methods: Twenty-seven consecutive patients with radiologically confirmed central canal or lateral recess stenosis underwent lumbar laminectomy for neurogenic symptoms. Surgical specimens comprising en bloc excision of LF and medial inferior facet (to retain LF and FJ relationships) were examined microscopically following staining with haematoxylin-eosin and Miller’s elastic stain. Controls were facet/LF specimens from 89 cadaver lumbar spines. Results: Mean LF thickness was 8.9 mm (+/− 0.3 mm SEM) at the operated levels and 2.9 mm (+/− 0.3 mm) at the non-operated, adjacent levels (p < 0.01). Twenty-eight synovial cysts (8 bilateral, 12 unilateral) were present at a single level in 20 (74%) patients. Synovial cysts per spine level were: L1/2 = 0; L2/3 = 3; L3/4 = 7; L4/5 = 16; L5/S1 = 2. The cyst levels all showed advanced osteoarthritis and LF degeneration. Ten patients (50 %) with cysts had pre-existing degenerative spondylolisthesis (DS). Only 5 patients had pre-operative radiological apperances of unilateral facet cysts. Therefore 82 % of our observed synovial cysts were microscopic or occult. The synovial cysts communicated with the FJ via a bursa-like cleft within the LF, and their linings of synoviocytes and other cells contained fragments shed from the articular surface. The control cadaver specimens revealed that a synovial bursa or intra-ligamentous out-pouching from the synovial cavity was present in 90% of normal LF at L4/5 and was up to 12 mm in length. This intra-ligamentous synovial recess, either wholly or partially lined by synoviocytes, was only present in 55% of specimens at L1/2 with a maximum length of 5 mm. Several other juxtafacet cyst types were observed in the experimental group and a novel classification based upon pathological findings is presented. Discussion: Para-facetal intraspinal cysts are common in degenerative lumbar spinal stenosis. DS is also a frequent finding but is statistically unrelated to cyst formation (Chi-square: p=0.187). We have found that debris from osteoarthritic facet joints enters a bursa-like cleft within the LF where it becomes incorporated into the wall where it excites a granulomatous reaction leading to blockage and synovial cyst formation. The existence of this channel has not been reported previously. We suggest that microscopic synovial cysts contribute significantly to the ligamentous thickening seen in LCS. We also present a novel classification of juxtafacet cysts based on our pathological findings

Aim: To measure the effect of X-stop interspinous decompression device on the dural sac and foraminal area at 6 and 24 months post operatively at the instrumented level in patients with symptomatic lumbar canal stenosis. Design: Prospective Observational Study of 48 patients. Methods: Patients due to have an X stop procedure were included and had a positional MRI scan preoperatively and 6 & 24 months post operatively. Foraminal area was measured in flexion and extension position whereas dural cross sectional area was measured in erect, neutral, flexion and extension positions. Osiris 4.17 software program was used to measure the canal and foraminal dimensions. The data was analysed using paired t test on SPSS ver.15.01. Results: Forty-eight patients (25 male and 23 female) underwent scans preoperatively and at six months. Twenty-nine patients had single level and 19 had double level procedures. Three patients had removal of X stop and 5 did not have scan at 24 months leaving 40 patients scanned at 24 months. Of these 38 scans were complete and were included. We noted increase in mean dural sac area in all positions. The mean dural sac area increased from 131 mm2 to 143 mm2 (p=0.144) at 6 months and from 137 mm2 to 202 mm2 (p= 000) at 24 months in standing position. The difference in pre-operative measurements in the six and 24-month measurements is because of the different patient numbers scanned. There were similar increased dural sac areas in the other positions. The mean foraminal areas were measured in flexion and extension and the measurements in extension were increased from 66.58 mm2 to 79.51 mm2 (p=. 001) at 6 months and from 68.10 to 69.57 mm2 (p=0.752) at 24 months on left side; and increased from 63.75 mm2 to 71.65 mm2 (p=0.036) at 6 months, from 65.54 mm2 to 68.01mm2 (p=0.440) at 24 months on right side. Thus there is a small increase in foraminal areas and statistically significant increase in dural sac areas at 24 months. Conclusion: X-stop interspinous device remains effective in decompressing the stenosed spinal segment by increasing the anatomic dural cross sectional areas and foraminal areas of spinal canal at 24 months post operatively, thus providing symptomatic relief from lumbar canal stenosis

Aim: To study the effect of X-stop interspinous decompression device on the lumbar spine kinematics at 6 and 24 months post operatively at the instrumented and adjacent levels in patients with symptomatic lumbar canal stenosis. Design: Prospective Observational Study of 48 patients. Methods: Patients due to have an X stop procedure were included and had a positional MRI scan preoperatively, 6 and 24 months post operatively in erect, flexion, extension and neutral position. Disc heights, endplate angles, segmental and lumbar spine motion was measured at stenosed instrumented and adjacent levels. Osiris 4.17 software program was used to measure the canal and foraminal dimensions. The data was analysed using paired t test on SPSS ver.15.01. Results: Forty-eight patients (25 Male and 23 Female) underwent scans preoperatively and at 6 months. Twenty-nine patients had single level and 19 had double level procedures. Three patients had removal of X stop and 5 did not have scan at 24 months, leaving 40 patients scanned at 24 months. Of these, 38 scans were complete and were included. Mean anterior disc height reduced from 7.1 mm to 6.3 mm (p=0.004) from 48 scans at 6 months and from 7.2 mm (pre-operative) to 5.9 mm (at 24 months) – (p=0.000) from 38 scans at 24 months at the instrumented level. We hypothesise that the reduction in anterior disc heights could be a result of the interspinous distraction plus the natural progression of spinal stenosis and ageing. There was no significant change in posterior disc heights at instrumented level or adjacent levels. The mean lumbar spine motion was 22.89o, 21.3 o and 21o (p=0.183) preoperatively, 6 and 24 months respectively. The total range of movements of lumbar spine and individual segments were measured. There was no significant change in the segmental range of motion at instrumented and adjacent levels. Conclusion: X-stop interspinous device does not significantly alter the kinematics of lumbar spine at instrumented and adjacent levels at 6 and 24 months postoperatively