Lumbar total disc replacement: predictors for long-term outcome.

PURPOSE: We aimed to identify patient characteristics associated with favourable long-term outcomes after lumbar total disc replacement (TDR). METHODS: We analysed a cohort of 82 patients with degenerative disc and chronic low back pain (LBP) who were treated with TDR and originally participated in a randomised trial comparing TDR and multidisciplinary rehabilitation. Potential predictors were measured at baseline, and the outcomes assessed 8 years after they received allocated treatment. Outcome measures were dichotomised according to whether the participants achieved a clinically important functional improvement (15 points or more on the Oswestry Disability Index, ODI) (primary outcome) and whether they were employed at 8-year follow-up (secondary outcome). Associations between potential predictors and outcomes were modelled using logistic regression. For the secondary outcome, the results were also organised in a prediction matrix and expressed as probabilities. RESULTS: For 71 patients treated with TDR according to protocol, the follow-up time was 8 years. For a subgroup of 11 patients randomised to rehabilitation who crossed over and received TDR, the median postoperative follow-up time was 72 (range 41-88) months. Of all assessed baseline variables, only presence of Modic changes (type 1 and/or 2) was statistically significantly associated with an improvement of ≥ 15 ODI points. The probability of employment at 8-year follow-up was 1% for patients with ≥ 1 year of sick leave, comorbidity, ODI ≥ 50 and ≤ 9 years of education prior to treatment, and 87% for patients with < 1 year of sick leave, no comorbidity, ODI < 50 and higher education. CONCLUSIONS: Patients with Modic changes prior to the TDR surgery were more likely to report a clinically important functional improvement at long-term follow-up. Comorbidity, low level of education, long-term sick leave and high ODI score at baseline were associated with unemployment at long-term follow-up.

Surgical management of lumbar spinal stenosis: a survey among Norwegian spine surgeons.

BACKGROUND: Symptomatic lumbar spinal stenosis (LSS) is the most common reason for lumbar surgery in the elderly. There is growing evidence that decompressive surgery offers an advantage over non-surgical management for selected patients with persistent severe symptoms. Based on treatment traditions, open laminectomy has been the gold standard surgical treatment, but various other surgical and non-surgical treatments for LSS are widely used in clinical practice. Therefore, we conducted a survey study to capture potential diversities in surgeons' management of LSS in Norway. METHODS: All spine surgeons in Norway were contacted by e-mail and asked to answer a 20-item questionnaire by using an Internet-based survey tool. We asked eight questions about the respondent (gender, surgical specialty, workplace, experience, number of surgeries performed per year, use of magnification devices) and 12 questions about different aspects of the surgical treatment of LSS (indication for surgery and preoperative imaging, different surgical techniques, clinical outcome). RESULTS: The questionnaire was answered by 51 spine surgeons (47% response rate). The preferred surgical technique for LSS in Norway is microdecompression via a unilateral approach and crossover technique, followed by microdecompression via a bilateral approach. Other techniques are not much used in Norway. CONCLUSIONS: Most Norwegian spine surgeons use minimally invasive decompression techniques in the surgical treatment of LSS, and unilateral microsurgical decompression with crossover decompression is the preferred technique. Where evidence is lacking (e.g., fusion procedures), there is a larger variation of opinions and preferred procedures among Norwegian spine surgeons.

Minimally invasive decompression versus x-stop in lumbar spinal stenosis: a randomized controlled multicenter study.

STUDY DESIGN: Prospective randomized controlled multicenter study. OBJECTIVE: To compare the effect of X-Stop with minimally invasive decompression (MID) in patients with neurogenic intermittent claudication due to lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: Lumbar spinal stenosis is the most common indication for operative treatment in elderly. Laminectomy has been the "gold standard," but MID is now widely used. Another minimally invasive surgery option is X-Stop showing good result compared with nonoperative treatment, but showing higher reoperation rate than laminectomy. METHODS: We enrolled 96 patients aged 50 to 85 years, with symptoms of neurogenic intermittent claudication within 250-m walking distance and 1- or 2-level lumbar spinal stenosis, randomized to either MID or X-Stop. Primary outcome was Zurich Claudication Questionnaire in this intention-to-treat analysis. Secondary outcome was Oswestry Disability Index, EuroQol 5-dimensional questionnaire, numerical rating scale 11 for lower back pain and leg pain, and risk for secondary surgery and complications. RESULTS: No significant differences were found in Zurich Claudication Questionnaire between the groups at any follow-ups. Both groups had a statistical and clinical significant improvement at 6 weeks and throughout the 2-year observation period. The number of patients having secondary surgery due to persistent or recurrent symptoms was significantly higher in the X-Stop group, odds ratio (95% confidence interval) = 6.5 (1.3-31.9). Complication rate was similar and low, but more severe for MID. CONCLUSION: Both MID and X-Stop led to significant symptom improvements. There were no significant clinical differences in effect between the methods at any of the follow-up time points. X-Stop had significant higher risk of secondary surgery. Complication was more severe for MID.

Cost-effectiveness of total disc replacement versus multidisciplinary rehabilitation in patients with chronic low back pain: a Norwegian multicenter RCT.

STUDY DESIGN: Randomized clinical trial with 2-year follow-up. OBJECTIVE: To evaluate the cost-effectiveness of total disc replacement (TDR) versus multidisciplinary rehabilitation (MDR) in patients with chronic low back pain (CLBP). SUMMARY OF BACKGROUND DATA: The existing studies on CLBP report cost-effectiveness of fusion surgery versus disc replacement and fusion versus rehabilitation. This study evaluated the cost-effectiveness of TDR versus MDR. METHODS: Between April 2004 and May 2007, 173 patients with CLBP (>1 yr) were randomized to TDR (n = 86) or MDR (n = 87). Treatment effects (Euro Qol 5D [EQ-5D] and Short Form 6D [SF-6D]) and relevant direct and indirect costs at 6 weeks and at 3, 6, 12, and 24 months after treatment were assessed. Gain in quality-adjusted life years (QALYs) after 2 years was estimated. Cost-effectiveness was expressed as an incremental cost-effectiveness ratio. RESULTS: The mean QALYs gained (standard deviation) using EQ-5D was 1.29 (0.53) in the TDR group and 0.95 (0.52) in the MDR group, a significant difference of 0.34 (95% confidence interval 0.18-0.50). The mean total cost per patient in the TDR group was &OV0556;87,622 (58,351) compared with &OV0556;74,116 (58,237) in the MDR group, which was not significantly different (95% confidence interval: -4041 to 31,755). The incremental cost-effectiveness ratio for the TDR procedure varied from &OV0556;39,748 using EQ-5D (TDR cost-effective) to &OV0556;128,328 using SF-6D (TDR not cost-effective). The dropout rate was 20% (15% TDR group, 24% MDR group). Five patients moved from the MDR to the TDR group, whereas 9 patients randomized to TDR declined surgery. Using per-protocol analysis instead of intention-to-treat analysis indicated that TDR was not cost-effective, irrespective of the use of EQ-5D or SF-6D. CONCLUSION: In this study, TDR was cost-effective compared with MDR after 2 years when using EQ-5D for assessing QALYs gained and a willingness to pay of &OV0556;74,600 (kr500,000/QALY). TDR was not cost-effective when SF-6D was used; therefore, our results should be interpreted with caution. Longer follow-up is needed to accurately assess the cost-effectiveness of TDR. LEVEL OF EVIDENCE: 2.

Comparison of the SF6D, the EQ5D, and the oswestry disability index in patients with chronic low back pain and degenerative disc disease.

BACKGROUND: The need for cost effectiveness analyses in randomized controlled trials that compare treatment options is increasing. The selection of the optimal utility measure is important, and a central question is whether the two most commonly used indexes - the EuroQuol 5D (EQ5D) and the Short Form 6D (SF6D) - can be used interchangeably. The aim of the present study was to compare change scores of the EQ5D and SF6D utility indexes in terms of some important measurement properties. The psychometric properties of the two utility indexes were compared to a disease-specific instrument, the Oswestry Disability Index (ODI), in the setting of a randomized controlled trial for degenerative disc disease. METHODS: In a randomized controlled multicentre trial, 172 patients who had experienced low back pain for an average of 6 years were randomized to either treatment with an intensive back rehabilitation program or surgery to insert disc prostheses. Patients filled out the ODI, EQ5D, and SF-36 at baseline and two-year follow up. The utility indexes was compared with respect to measurement error, structural validity, criterion validity, responsiveness, and interpretability according to the COSMIN taxonomy. RESULTS: At follow up, 113 patients had change score values for all three instruments. The SF6D had better similarity with the disease-specific instrument (ODI) regarding sensitivity, specificity, and responsiveness. Measurement error was lower for the SF6D (0.056) compared to the EQ5D (0.155). The minimal important change score value was 0.031 for SF6D and 0.173 for EQ5D. The minimal detectable change score value at a 95% confidence level were 0.157 for SF6D and 0.429 for EQ5D, and the difference in mean change score values (SD) between them was 0.23 (0.29) and so exceeded the clinical significant change score value for both instruments. Analysis of psychometric properties indicated that the indexes are unidimensional when considered separately, but that they do not exactly measure the same underlying construct. CONCLUSIONS: This study indicates that the difference in important measurement properties between EQ5D and SF6D is too large to consider them interchangeable. Since the similarity with the "gold standard" (the disease-specific instrument) was quite different, this could indicate that the choice of index should be determined by the diagnosis.

[Neurophysiological monitoring during surgery]. / Nevrofysiologisk monitorering under kirurgi.

BACKGROUND: Intraoperative neurophysiological monitoring has become increasingly important in interventions involving risk of damage to the nervous system. We aim to provide an overview of possibilities and limitations on the use of intraoperative neurophysiological methods. METHOD: The article is based on a review of relevant textbooks and articles from own literature archives and selective searches in PubMed, combined with the authors' own clinical experience. RESULTS: Intraoperative neurophysiological monitoring includes both continuous monitoring of neural tissue and localisation of vital neurological structures. This monitoring can reduce the risk of damage to nerves and neural pathways and is used most frequently in scoliosis and neurosurgical operations. The need for neurophysiological monitoring influences the choice of anaesthesia, as some anaesthetics affect the monitoring. INTERPRETATION: Intraoperative neurophysiological monitoring is dependent on good cooperation between neurophysiologists, surgeons, anaesthetists and the other specialities involved.

Predictors of outcome after surgery with disc prosthesis and rehabilitation in patients with chronic low back pain and degenerative disc: 2-year follow-up.

PURPOSE: A prospective study to evaluate whether certain baseline characteristics can predict outcome in patients treated with disc prosthesis or multidisciplinary rehabilitation. METHODS: Secondary analysis of 154 patients with chronic low back pain (LBP) for at least 1 year and degenerative discs originally recruited for a randomized trial. Outcome measures were Oswestry Disability Index (ODI) dichotomized to < or ≥15 points improvement and whether subjects were working at 2-year follow-up. A multiple logistic regression analysis was used. RESULTS: In patients treated with disc prosthesis, long duration of LBP and high Fear-Avoidance Beliefs for work (FABQ-W) predicted worse ODI outcome [odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.2-3.2 and OR = 1.7, CI 1.2-2.4 for every 5 years or 5 points]. Modic type I or II predicted better ODI outcome (OR = 5.3, CI 1.1-25.3). In patients treated with rehabilitation, a high ODI, low emotional distress (HSCL-25), and no daily narcotics predicted better outcome for ODI (OR = 2.5, CI 1.4-4.5 for every 5 ODI points, OR = 2.1, CI 1.1-5.1 for every 0.5 HSCL points and OR = 23.6, CI 2.1-266.8 for no daily narcotics). Low FABQ-W and working at baseline predicted working at 2-year follow-up after both treatments (OR = 1.3, CI 1.0-1.5 for every 5 points and OR = 4.1, CI 1.2-13.2, respectively). CONCLUSIONS: Shorter duration of LBP, Modic type I or II changes and low FABQ-W were the best predictors of success after treatment with disc prosthesis, while high ODI, low distress and not using narcotics daily predicted better outcome of rehabilitation. Low FABQ-W and working predicted working at follow-up.

Surgery with disc prosthesis versus rehabilitation in patients with low back pain and degenerative disc: two year follow-up of randomised study.

OBJECTIVE: To compare the efficacy of surgery with disc prosthesis versus non-surgical treatment for patients with chronic low back pain. DESIGN: A prospective randomised multicentre study. SETTING: Five university hospitals in Norway. PARTICIPANTS: 173 patients with a history of low back pain for at least one year, Oswestry disability index of at least 30 points, and degenerative changes in one or two lower lumbar spine levels (86 patients randomised to surgery). Patients were treated from April 2004 to September 2007. INTERVENTIONS: Surgery with disc prosthesis or outpatient multidisciplinary rehabilitation for 12-15 days. MAIN OUTCOME MEASURES: The primary outcome measure was the score on the Oswestry disability index after two years. Secondary outcome measures were low back pain, satisfaction with life (SF-36 and EuroQol EQ-5D), Hopkins symptom check list (HSCL-25), fear avoidance beliefs (FABQ), self efficacy beliefs for pain, work status, and patients' satisfaction and drug use. A blinded independent observer evaluated scores on the back performance scale and Prolo scale at two year follow-up. RESULTS: The study was powered to detect a difference of 10 points on the Oswestry disability index between the groups at two years. At two years there was a mean difference of -8.4 points (95% confidence interval -13.2 to -3.6) in favour of surgery. In the analysis of prespecified secondary outcomes, there were significant differences in favour of surgery for low back pain (mean difference -12.2, -21.3 to -3.1), patients' satisfaction (63% (n = 46) v 39% (n = 26)), SF-36 physical component score (mean difference 5.8, 2.5 to 9.1), self efficacy for pain (mean difference 1.0, 0.2 to 1.9), and the Prolo scale (mean difference 0.9, 0.1 to 1.6). There were no significant differences in return to work, SF-36 mental component score, EQ-5D, fear avoidance beliefs, Hopkins symptom check list, drug use, and the back performance scale. One serious complication of leg amputation occurred during surgical revision of a polyethylene dislodgement. The drop-out rate was 20% (34) and the crossover rate was 6% (5). CONCLUSIONS: Surgical intervention with disc prosthesis for chronic low back pain resulted in a significantly greater improvement in the Oswestry score compared with rehabilitation, but this improvement did not clearly exceed the prespecified minimally important clinical difference between groups of 10 points, and the data are consistent with a wide range of differences between the groups, including values well below 10 points. The potential risks of surgery and the substantial amount of improvement experienced by a sizeable proportion of the rehabilitation group also have to be incorporated into overall decision making. Trial registration NCT 00394732.