Objectives: To examine and correlate the presence of neovascularisation, crystalline pyrophosphate deposits and other hisotological features in the disc and discogenic pain established by spinal probing and discography under aware state endoscopic visualisation.

Design: Tissue removed from intervertebral discs of 224 patients during surgery were examined by direct and polarised microscopy to identify the presence of calcium pyrophosphate and neovascularisation.

Material and Methods: Histology was correlated to the diagnostic provocative findings of spinal probing and discography, discal palpation during aware state endoscopy.

Results: Calcium Pyrophosphate: 20/224 (9%) patients demonstrated calcium pyrophosphate in the discs. Fourteen had pain reproduced on probing or discography; 13/20 (65%) of patients had either an annular collection or leak at the index level; 6/20 had an extradiscal cause of pain.

Neovascularisation: Thirty-seven out of 224 (16.5%) patients showed neovascularisation in the disc; four discs had crystalline pyrophosphate deposits; 33/37 (90%) had pain on probing and/or discography.

Conclusion: The presence of pyrophosphate in a disc without a tear or leak is not associated with annular tenderness. The presence of pyrophosphates in radial tears or leaks is associated with annular tenderness. Annular tears or leaks are not directly correlated to the presence of pyrophosphates. There is a high correlation between pain provocation and neovascularisation.

Objective: To analyse the incidence and gravity of reported complications that arise in spinal surgery and assess the comparative safety, or otherwise, of Endoscopic Laser Foraminoplasty.

Design: Prospective independently analysed study of complications arising during the six weeks following Endoscopic Laser Foraminoplasty was correlated and compared to a meta-analysis of reported data on complications in conventional spinal surgery.

Subjects: Nine hundred and fifty-eight procedures performed on 716 patients

Outcome measures: Occurrence of complications.

Results: The cohort integrity of operative and review records at six weeks after surgery was 100%. Twenty four complications occurred in 23 patients: nine cases of discitis (one infective) (0.9%), one dural tear (0.1%), one deep wound infection (0.1%), two patients suffered a foot drop (one transient) (0.2%), one myocardial infarction (0.1%), one erectile dysfunction (0.1%) and one post operative panic attacks (0.1%). MRI later demonstrated eight residual disc herniations (0.8%). The overall surgical complication rate was 1.6%. Meta-analysis of conventional spinal surgery reported overall complication rates for fusion (11.8%), decompression (7.6%), discectomy (6.0%) and chemonucleolysis (9.6%).

Conclusions: The complication rate of Endoscopic Laser Foraminoplasty is significantly lower than that reported following conventional spinal surgery (P < 0.01).

Objectives: To assess the efficacy and outcome of endoscopic aware state pain source definition combined with endoscopic decompression of the foramen, mobilisation and neurolysis of the exiting and transiting nerves and ablation of osteophytes in patients with spondylolytic spondylolisthesis followed for a minimum of two years.

Design: This prospective study determined the outcome of endoscopic foraminal decompression in symptomatic spondylolytic-spondylolisthesis.

Subjects: Sixteen males, and fourteen females with an average age of 46 years

Outcome measures: Results were analysed using the percentage change in Oswestry Disability Index, and percentage change in visual analogue pain (VAP) scores.

Results: One hundred percent cohort integrity was maintained at the final follow up. Using a percentage change in Oswestry Disability Index of 50 or more to determine good and excellent outcomes, 75% (22 out of 30) exceeded this value with five (17%) having 100% benefit for the procedure.

Conclusion: These results indicate that Endoscopic Laser Foraminoplasty provides a minimalist means of exploring the extraforaminal zone, the lytic defect, the foramen, its contents, and the epidural space and performing decompression, discectomy, osteophytectomy, perineural neurolysis in patients with spondylolytic spondylolisthes. Done in an aware state, it serves to identify and localise the source of pain generation.

Objectives: The view that patients low back pain presenting with ‘abnormal’ psychometric and poor DRAM scores predict an unsatisfactory surgical outcome is considered controversial. This prospective study was designed to identify if DRAM Scores (Scores of Distress Risk Assessment Method) is a predictive determinant or a reactive instrument in regard to the outcome of Endoscopic Foraminoplasty.

Design: Pre- and postoperative assessment of disability and DRAM at two years.

Subjects: One hundred and eighty-five patients (86 males and 99 females) underwent an Endoscopic Laser Foraminoplasty between April 1997 and November 1998.

Outcome measures: Oswestry Disability Scale, and the Visual Analogue Pain Scale and the DRAM scores. Patients were categorised by their pre-op DRAM score. Kruskal-Wallis analysis of variance and a regression analysis were performed.

Results: There was significant improvement in disability and pain scores at two years. (p< 0.05). A significant difference in median DRAM between the preoperative and postoperative score at two years was noted.

Conclusion: The DRAM score highlights individuals in distress who may need psychological support and physical treatment for optimum benefit from endoscopic spinal intervention. While the DRAM score predicted the patients’ disability and pain it failed to predict percentage benefit gain in outcome.

Objective: To determine the in vitro difference in stability in a functional spinal unit (FSU) following bilateral laminotomy, and compare it to the instability resulting from laminectomy.

Design: The normal and injured spines were subjected to flexion, extension, lateral bending and torsional moments.

Subjects: Six fresh human cadaver lumbar spines were injured sequentially at the L4–5 level: bilateral laminotomy and laminectomy.

Outcome measures: The three-dimensional motion behaviour of each spine before and after the two injuries was recorded using a magnetic motion sensor. The data from all five spines was pooled for statistical analysis.

Results: With flexion and extension loading, bilateral laminotomy induced significantly less sagittal angulation and translation in the FSU than did laminectomy. Significant increase in coronal translation occurred with laminectomy in spines subjected to lateral bending loads. There were no significant differences between the two techniques in coronal plane angulation with lateral bending loads and torsional loads.

Conclusion: The increase in motion seen with laminectomy in sagittal angulation/translation, and coronal translation in this in vitro model may represent clinical instability, and may be responsible for continued symptomatology in these patients. Preservation of the lamina, spinous processes, and the posterior ligamentous structures significantly enhances the biomechanical stability of the FSU.