Modic (endplate) changes in the lumbar spine: bone micro-architecture and remodelling.

PURPOSE: In the literature, inter-vertebral MRI signal intensity changes (Modic changes) were associated with corresponding histological observations on endplate biopsies. However, tissue-level studies were limited. No quantitative histomorphometric study on bone biopsies has yet been conducted for Modic changes. The aim of this study was to characterise the bone micro-architectural parameters and bone remodelling indices associated with Modic changes. METHODS: Forty patients suffering from disabling low back pain, undergoing elective spinal surgery, and exhibiting Modic changes on MRI (Modic 1, n = 9; Modic 2, n = 25; Modic 3, n = 6), had a transpedicular vertebral body biopsy taken of subchondral bone. Biopsies were first examined by micro-CT, for 3D morphometric analysis of bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation, trabecular number, and structure model index. Then, samples underwent histological analysis, for determination of bone remodelling indices: osteoid surface to bone surface ratio (OS/BS), eroded surface to bone surface (ES/BS) and osteoid surface to eroded surface ratio (OS/ES). RESULTS: Micro-CT analysis revealed significantly higher BV/TV (up to 70% increase, p < 0.01) and Tb.Th (up to +57%, p < 0.01) in Modic 3 biopsies, compared to Modic 1 and 2. Histological analysis showed significantly lower OS/BS in Modic 2 biopsies (more than 28% decrease, p < 0.05) compared to 1 and 3. ES/BS progressively decreased from Modic 1 to 2 to 3, whereas OS/ES progressively increased with significantly higher values in Modic 3 (up to 159% increase, p < 0.05) than in Modic 1 and 2. CONCLUSIONS: Significant differences were found in bone micro-architectural parameters and remodelling indices among Modic types. Modic 1 biopsies had evidence of highest bone turnover, possibly due to an inflammatory process; Modic 2 biopsies were consistent with a reduced bone formation/remodelling stage; Modic 3 biopsies suggested a more stable sclerotic phase, with significantly increased BV/TV and Tb.Th compared to Modic 1 and 2, linked to increased bone formation and reduced resorption.

Failed Back Surgery Syndrome: A Review Article.

Postsurgical spine syndrome is becoming an increasingly common challenge for clinicians who deal with spinal disorders owing to the expanding indications for spinal surgery and the aging world population. A multidisciplinary approach is most appropriate for patients who are unlikely to benefit from further formal surgical intervention. Anticonvulsant medications are effective in managing neuropathic pain after surgery, whereas opioids are rarely beneficial. Neuromodulation via a surgically implanted dorsal column neurostimulator is gaining popularity owing to its substantial superiority over conventional medical management and/or further surgical intervention. However, considering that prevention is always better than cure, spinal surgeons need to be well aware of the many poor prognostic indicators for spinal surgery, particularly psychosocial overlay.

Do bacteria play an important role in the pathogenesis of low back pain?

Considerable interest has been generated recently regarding an alternative hypothesis for the pathogenesis of low back pain and radiculopathy in the presence of intervertebral disc prolapse. Traditionally, back pain and radicular (sciatic) symptoms have been attributed to mechanical compression of neural tissue by herniated disc material and to inflammation caused by exposure of the nerve roots to disc tissue. Recent research however has suggested that low-grade infection within the intervertebral disc by anaerobic bacteria may be responsible. The development of Modic changes in the corresponding adjacent vertebral endplates has also been suggested as an indicator of infection. This article is a thorough review of the current literature regarding the hypothesis that low-grade anaerobic bacterial infection may be the cause of disabling low back pain and radiculopathy.

The outcome of pedicle screw instrumentation removal for ongoing low back pain following posterolateral lumbar fusion.

BACKGROUND: Our aim was to determine whether patients derived benefit from removal of pedicle screw instrumentation for axial pain without other cause using our surgical technique and patient selection. A secondary aim was to investigate factors that were associated with poorer outcomes for this procedure as well as complication rate in this cohort. METHODS: Theater records from a single spinal surgeon's practice were reviewed to identify patients that had undergone lumbar fusion for discogenic back pain with subsequent pedicle screw instrumentation removal (Expedium, DePuy Synthes) in the preceding 3 years with a minimum of 18 months follow-up. Inclusion criteria were persisting midline axial back pain with computed tomography (CT)-confirmed solid fusion with non-radicular symptoms and nil other potential causes found, e.g., infection. Case note review along with pre- and post-operative Oswestry disability index (ODI) questionnaires and visual analog scores (VAS) were assessed for all patients. Surgical technique included re-use of previous midline posterior incision and the Wiltse approach with removal of implants, confirmation of a solid fusion mass, washout and bone grafting of removal sites. RESULTS: From 50 consecutive patients who underwent removal of posterolateral instrumentation for an index elective lumbar fusion for discogenic back pain, 34 patients were identified that met the criteria with a mean follow-up of 25 months (range, 18-36 months). The VAS and ODI improved in 22/34 (65%) of participants. The mean cohort VAS score was 6.6 pre-surgery and 4.3 post-surgery (P=0.04). Preoperative and postoperative mean Oswestry disability scores were 64 and 41, respectively (P=0.05). There was a statistically significant difference in the proportion of patients with poorer compared to satisfactory outcomes with regards to compensable status, preoperative grade II opioid use and shorter time between fusion and removal procedure. Complications were one postoperative hematoma and one superficial wound infection, both of which settled without re-operation. CONCLUSIONS: Approximately two thirds of patients were satisfied with removal of instrumentation for treatment of residual low back pain (LBP) following elective lumbar fusion and recorded reduced VAS and grade II opioid use. A subset of patients remained that did not derive benefit and were associated with compensable status, preoperative grade II opioid use and a shorter time between fusion and removal procedure. A prospective cohort study with preoperative diagnostic injections and standardized imaging and microscopic techniques would strengthen future studies. However, this study suggests that removal of instrumentation is safe and provides modest benefit as a palliative procedure for a subset of patients with significant disability from chronic LBP without an underlying cause following lumbar fusion.

Potential risk factors for prolonged recovery following whiplash injury.

A retrospective analysis of insurance data was made of 600 individuals claiming compensation for whiplash following motor vehicle accidents. Three hundred randomly selected claimants who had settled their injury claims within 9 months of the accident were compared with 300 who had settled more than 24 months after the accident. We compared the two groups to identify possible risk factors for prolonged recovery, for which settlement time greater than 24 months was a marker. Variables considered included demographic factors, type of collision, degree of vehicle damage, workers compensation, prior claim or neck disability, treatment and time to settlement. Consulting a solicitor was associated with a highly significant, four-fold increase of late settlement of the claim. A concurrent workers' compensation claim, prior neck disability and undergoing physiotherapy or chiropractic treatment were weakly associated with late settlement. The degree of damage to the vehicle (as indicated by cost of repairs) was not a significant predictor of late settlement. Late settlement may be the direct effect of legal intervention, independent of the severity of the injury. Whilst the financial benefit to the claimant of consulting a solicitor is apparent, the benefit of prolonged disability is not. It may be to the advantage of both insurers and claimants if those likely to proceed to late settlement could be recognised early and their claims settled expeditiously.