Introduction: Intra-Discal Electrothermal Therapy (IDET) has been used to treat chronic discogenic low back pain. 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 Each segment was compressed, normally to 1 kN, while a miniature pressure transducer was withdrawn from posterior to anterior across the mid-sagittal diameter of the disc producing a baseline stress profile.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 in annular stress peaks associated with degenerative discs, 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.

Purposes of the study and background: This study tests the hypothesis that it is possible to visualise the cervical spine musculature using ultrasound. The use of diagnostic ultrasound is well established for assessing other anatomical regions; whereas the cervical spine has received little attention. Other available imaging procedures can be resource intensive with recognized risks and do not give an indication of structural detail. Ultrasound has the potential to resolve these inadequacies and would therefore be appealing.

Summary of the methods and the results: 10 healthy volunteers (age range: 21–36 years, 6 females, 4 males) were evaluated using a 8-16MHz linear array transducer (Diasus Dynamic Imaging, UK) and a 16MHz CL15-7 linear array scanhead transducer (Phillips ATL HDI 5000 SonoCT, Netherlands). Subjects were seated with their neck in a neutral position. The transducer was orientated transversely, and initially placed on the thyroid cartilage. Successive images were taken as the transducer was moved laterally across the anterior triangle, over the sternocleidomastoid, into the posterior triangle, ending in the posterior midline. Landmarks, with characteristic ultrasonic appearances, were identified to aid orientation e.g. carotid artery. Both machines produced images that clearly displayed the musculature of the cervical spine. Composite images were obtained of the anterior and posterior aspects of the neck (Figure 1) to provide information regarding the spatial orientation and relationship between the muscles.

Conclusion: This study concludes that modern ultrasound equipment provides cervical spine soft tissue images of a quality suitable for diagnostic applications. It also has the advantages of being a risk free, economic and portable procedure.

Purposes of the study and background: Diagnostic interventional procedures are often performed on patients who suffer from cervical facet joint pain and discogenic pain emanating from the cervical region. These procedures require radiographic imaging to confirm placement of instruments e.g. needles. However, these techniques are unable to provide real-time images hence prolonging the intervention. It would be of benefit to have an imaging tool that is capable of visualising needle insertion in real-time whilst preventing side effects. The purpose of this study was to determine the ultrasonic appearance of cervical facet joints in vivo and describe a standardized transducer position to visualise intervertebral discs and facet joints.

Summary of the methods and the results: 10 healthy volunteers (age range: 21–36 years, 6 females, 4 males) were evaluated using an 8-16MHz linear array transducer (Diasus Dynamic Imaging). Subjects were scanned in a prone, lateral position. The transducer was placed in the posterior triangle orientated longitudinally, initially along the posterior border of sternocleidomastoid and then moved in a cranial-caudal direction. By adjusting the angle (in the antero-posterior direction) of the transducer about a fixed position; facet joints and discs were located. The characteristic V shaped appearance of the facet joint emanates from the hyperechoic signal of the closely spaced transverse processes of adjacent vertebra (Figure1). Disc regions appeared as areas of high signal penetration into the spine with low amplitude signals returning from the disc.

Conclusion: The detail of facet joint and disc anatomy captured using ultrasound reveal it to be a viable imaging tool for interventional procedures. Noteworthy advantages of ultrasound include: its ability to provide real-time images economically, the option of portability and no known side effects.

Objective: Determine the incidence of abnormal somatosensory evoked potentials (SSEP) in patients with ‘at risk’ spinal cords undergoing anterior spinal deformity surgery.

Design: A retrospective chart and SSEP trace review of cases between 1982–2001.

Subjects: Patients undergoing elective anterior spinal deformity surgery were included. Excluded were those with inadequate SSEP monitoring or no pre-operative MRI scan.

Outcome measures: Paraparesis due to cord ischaemia based on an abnormal SSEP trace, i. e. > 50% decrease in SSEP baseline amplitude +/− > 10% increase in latency¹.

Results: Partial data was available for 1982–1990, thus analysis was based on cases between 1990–2001.871 patients underwent elective anterior spinal deformity surgery, 11% were ‘at risk cords’; 2% demonstrated intraoperative SSEP changes. Post operative paraparesis ws found in 0.6%. Intra-operative changes were significantly more common in ‘at risk cords’ (chi-squared test = 30.3, df = 2; p< 0.005). No statistical difference in the incidence of paraparesis in normal cords vs ‘at risk’ cords.

Conclusions: Post operative neurological deficit is rare in anterior spinal deformity surgery. Significant SSEP changes do occur with ligation of segmental vessels, implying cord ischaemia. Therefore, for the ‘at risk cord’, these patients should be considered for spinal cord monitoring and temporary clamping of segmental vessels prior to their division

Objective: To study the long term operative and non-operative outcome in patients with diastematomyelia (DM).

Design: A prospectively acquired database of all spinal patients seen jointly by the senior authors (JKW, JLF), was searched for patients with DM. Their notes and the database were then reviewed.

Subjects: Thirty-six patients were identified; twenty-one (58%) had associated scoliosis. There were 60 associated abnormalities in the 36 patients, most common being ten (27%) with leg length inequality. Twelve patients (33%) had no radiological bony abnormality. Twenty-four (66%) had neurosurgery, eleven (31%) untethering of filum alone and eleven (31%) with removal of a spur and closure of the DM as well. Nineteen (53%) underwent some sort of neuraxial shortening scoliosis correction/surgery. Twenty-eight (78%) were deemed to have a normal/independent neurological outcome, seventeen (61%) having neurosurgery and twelve (43%) scoliosis surgery.

Conclusions: Patients with DM have been followed up for many years. Good neurological outcomes can be anticipated in cases with untethering and with scoliosis correction alone. This series raises the question as to whether any unthethering procedure is necessary in these cases when neuraxial shortening is carried out for scoliosis cases.