To prospectively determine the relationship between the two most commonly used generic spinal outcome measures, the Oswestry Disability Index (ODI) and the Low Back Outcome Score (LBOS).

Outcome measures inform audit and research. Few spine surgical specific outcome measures are in general use. Generic measures are used for a variety of spinal disorders it is not known which is best or exactly how they relate for different conditions. Pre-operatively and two years post surgical results were available in 240 patients. There were 125 males, 115 females. Sub groups numbering 82 discetomy, 78 decompression, 26 revision and 19 fusions were analysed.

Average age 55 years (range 23-88). The pre op average ODI was 55% and the LBOS was 29. Correlation was -0.73. The overall post operative score at 2 years was 34% ODI and 37 LBOS, the correlation was better at -0.87.

The correlation between the two scores post operatively was very good for Discectomy surgery (-0.916) and fusion surgery (-0.907) but not so close pre operatively with Discectomy (-0.786) and fusion correlation poor at (-0.302). Revision surgery and decompression surgery had similar good correlation post operatively. The correlation of both outcome measures to the Modified Zung depression index was poor.

The poor pre operative correlation suggests that thresholds for surgery cannot be compared within registries using different measures. The post operative scores and change in scores correlate better. This is important in comparative studies using different outcomes scores within the same spine registry.

No conflict of Interest. Registered database and audit of service standard

Determine the detection rate of modern spinal implants using the current technology.

There is a paucity of data regarding detection rates of modern spinal implants using modern walk-through pulsed archway metal detectors (AMDs). No published reports compare detection capability with hand-held metal detectors (HHMDs).

ex-vivo & in-vivo comparison of detection rates using AMD & HHMD (set to maximum DoT sensitivities), in patients of varying Body Mass Index (BMI), implants, implant mass/density and alloys.

40 patients with: lumbar disc replacement (CoCr) (n=8), cervical disc replacement (CoCr) (1), posterior deformity instrumentation (17), anterior deformity instrumentation (2), anterior reconstruction (2), PLIF (6), interspinous distraction device (1), anterior cervical plate (2) ALIF (1), All implants were titanium unless indicated. Mean metal mass was 98g (range 6g-222g).

The AMD did not detect any instrumentation individually or in combination up to a titanium mass totalling 215g. The HHMD detected all instrumentation at a distance of 5cm; with the minimum mass being 2g

No implants were detected in patients by the AMD. The HHMD did not detect any anterior lumbar or thoracic surgical implants. It detected anterior cervical implants. The HHMD detected all posterior surgical implants. There was no significant relationship between detection, BMI, total metal mass, and metal density/segment.

AMD detectors do not detect modern spinal implants. HHMD detect all modern posterior spinal implants; this has implications for patient documentation.

Aim: The clinical and radiological outcomes of a prospective randomised controlled trial comparing Femoral Ring Allografts (FRA) to Titanium Cages (TC) for circumferential fusion are presented.

Methods: Eighty-three patients were recruited fulfilling strict entry requirements (> 6 months chronic discogenic Low Back Pain (LBP), failure of conservative treatment, one or two level discographically-proven discogenic pain). Five patients were excluded on technical infringements (unable to insert TC or FRA). From 78 patients randomised, 37 received FRA and 41 received TC. Posterior stabilisation was achieved with translaminar or pedicle screws. Patients completed the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) for back and leg pain, the Short-Form 36 (SF-36) pre-operatively and 6, 12 and 24 months post-operatively. Assessment of fusion was made by a panel of 6 individuals examining radiographs taken at the same specified time points.

Results: Clinical outcomes were available for all 83 patients (mean follow-up 28 months, range 24–75). Baseline demographic data showed no statistical difference between groups (p< 0.05). For patients receiving FRA, mean VAS (back pain) improved 2.0 points (p< 0.01), mean ODI improved 15 points (p=< 0.01), and mean SF-36 scores improved by > 11 points in 6 of 8 domains (p< 0.03). For patients receiving TC, mean VAS improved 1.1 points (p=0.004), mean ODI improved 6 points (p=0.01), and SF-36 improved significantly in only two of eight domains. Revision procedures and complications were similar in both groups. For the FRA group, 27 levels were fused from a total of 42 assessed (64.2%). For the TC group, 33 levels were fused from a total of 55 assessed (60%). This difference was not statistically significant p> 0.2.

Conclusion: The use of FRA in circumferential lumbar fusion was associated with superior clinical outcomes when compared to those observed following the use of TC. Both groups had similar fusion rates.

Introduction: Intra-Discal Electrothermal Therapy (IDET) has been used to treat chronic discogenic low back pain. Proposed mechanisms of action include denervation of the posterior annulus and collagen denaturation. Previous authors have reported on changes in internal disc mechanics following IDET including reduction in stress concentrations possibly leading to a more even distribution of load across the end-plate¹. A novel intradiscal decompression catheter has been developed to reduce local disc bulging in cases of contained prolapse. This new catheter is inserted percutaneously into a disc and advanced under radiographic control into a postero-lateral position targeting the herniation. The decompression catheter uses more focused heating and higher temperatures than previous devices and is intended to provide a local decompression of the disc through a thermally-mediated reduction in nuclear volume. The purpose of this study was to investigate changes in internal stress profiles following use of the new catheter.

Methods: Five cadaveric lumbar ‘motion segments’ were dissected from two spines (age 64–84 yrs). Each segment was compressed, normally to 1 kN, while a miniature pressure transducer was withdrawn from posterior to anterior across the mid-sagittal diameter of the disc producing a baseline stress profile. A decompression catheter was inserted into the disc and its position confirmed with plain radiography. The temperature of the catheter was increased to 90°c over a period of 14 minutes. Stress profiles were then repeated.

Results: Stress profiles in three of the five segments showed changes consistent with degenerative change. In these discs stress profiles following ‘treatment’ showed up to a 35% reduction in the magnitude of stress peaks in the posterior annulus. There was very little change in the distribution of stress in the two non-degenerate discs. Stress in the nucleus appeared unchanged in all discs.

Conclusions: Treatment of degenerate discs with the decompression catheter lead to a measurable alteration annular stress peaks that have been associated with degenerative disc disease, while non-degenerate discs were unaffected. These preliminary findings of an ongoing study suggest that the novel decompression catheter has a biomechanical effect in certain classes of disc.

Objective: Recent reports have suggested a low incidence of neurological complications following anterior deformity surgery; however in patients with co-existing intra-spinal anomalies no quantification of this risk has been made. Also, whether SSEP monitoring and soft clamping of segmental vessels prior to their division is necessary for these anterior procedures is controversial.

The aims of this study were to determine the incidence of significant SSEP changes in patients undergoing anterior spinal deformity surgery; to ascertain whether the ‘at risk’ cord was more likely to demonstrate significant intraoperative SSEP changes and what proportion of these changes yielded post operative neurological deficit.

Design: Retrospective analysis of operative notes and somatosensory evoked potential (SSEP) traces of patients who underwent anterior spinal deformity surgery between 1990–2001.

Subjects: All patients who underwent anterior spinal deformity surgery between 1990–2001, who had complete data sets (preoperative MRI scan, patient and procedural documentation and intraoperative SSEP traces) were included in the study.

Outcome measures: All post operative neurological deficits and significant SSEP changes were noted, whether or not patients had a ‘cord at risk’.

Results: In total, 871 patients had elective anterior spinal deformity surgery. Preoperative MRI revealed 95 patients (11%) demonstrated intraspinal anomalies on MRI but of these only 27 showed abnormal pre-operative SSEP i.e. cord at risk (CAR). Seventeen (2% of total) of this group developed abnormal intraoperative SSEP responses and ten (1.3%) occurred in the normal group. The incidence of post-operative paraparesis for the whole series was 0.6% (n=5): four in the CAR group, one in the normal cord group. Sensitivity of SSEPs in detecting potential neurological deficit was 100%; specificity 98.6%, positive predictive value 29.4% and negative predictive value 100%. Significant intraoperative SSEP changes occurred more frequently in the CAR group and were more likely to have post operative paraparesis.

Conclusions: SSEP monitoring is a sensitive and specific test, which in experienced hands yields no false positive results. Spinal cord monitoring and soft clamping of segmental vessels should be performed in patients with CAR undergoing anterior spinal deformity surgery to minimise the risk of post operative paraparesis.