Machine Learning Models for Predicting Disability and Pain Following Lumbar Disc Herniation Surgery.

Importance: Lumber disc herniation surgery can reduce pain and disability. However, a sizable minority of individuals experience minimal benefit, necessitating the development of accurate prediction models. Objective: To develop and validate prediction models for disability and pain 12 months after lumbar disc herniation surgery. Design, Setting, and Participants: A prospective, multicenter, registry-based prognostic study was conducted on a cohort of individuals undergoing lumbar disc herniation surgery from January 1, 2007, to May 31, 2021. Patients in the Norwegian Registry for Spine Surgery from all public and private hospitals in Norway performing spine surgery were included. Data analysis was performed from January to June 2023. Exposures: Microdiscectomy or open discectomy. Main Outcomes and Measures: Treatment success at 12 months, defined as improvement in Oswestry Disability Index (ODI) of 22 points or more; Numeric Rating Scale (NRS) back pain improvement of 2 or more points, and NRS leg pain improvement of 4 or more points. Machine learning models were trained for model development and internal-external cross-validation applied over geographic regions to validate the models. Model performance was assessed through discrimination (C statistic) and calibration (slope and intercept). Results: Analysis included 22 707 surgical cases (21 161 patients) (ODI model) (mean [SD] age, 47.0 [14.0] years; 12 952 [57.0%] males). Treatment nonsuccess was experienced by 33% (ODI), 27% (NRS back pain), and 31% (NRS leg pain) of the patients. In internal-external cross-validation, the selected machine learning models showed consistent discrimination and calibration across all 5 regions. The C statistic ranged from 0.81 to 0.84 (pooled random-effects meta-analysis estimate, 0.82; 95% CI, 0.81-0.84) for the ODI model. Calibration slopes (point estimates, 0.94-1.03; pooled estimate, 0.99; 95% CI, 0.93-1.06) and calibration intercepts (point estimates, -0.05 to 0.11; pooled estimate, 0.01; 95% CI, -0.07 to 0.10) were also consistent across regions. For NRS back pain, the C statistic ranged from 0.75 to 0.80 (pooled estimate, 0.77; 95% CI, 0.75-0.79); for NRS leg pain, the C statistic ranged from 0.74 to 0.77 (pooled estimate, 0.75; 95% CI, 0.74-0.76). Only minor heterogeneity was found in calibration slopes and intercepts. Conclusion: The findings of this study suggest that the models developed can inform patients and clinicians about individual prognosis and aid in surgical decision-making.

Patient Characteristics Associated With Worsening of Neck Pain-Related Disability After Surgery for Degenerative Cervical Myelopathy: A Nationwide Study of 1508 Patients.

BACKGROUND AND OBJECTIVES: Functional status, pain, and quality of life usually improve after surgery for degenerative cervical myelopathy (DCM), but a subset of patients report worsening. The objective was to define cutoff values for worsening on the Neck Disability Index (NDI) and identify prognostic factors associated with worsening of pain-related disability 12 months after DCM surgery. METHODS: In this prognostic study based on prospectively collected data from the Norwegian Registry for Spine Surgery, the NDI was the primary outcome. Receiver operating characteristics curve analyses were used to obtain cutoff values, using the global perceived effect scale as an external anchor. Univariable and multivariable analyses were performed using mixed logistic regression to evaluate the relationship between potential prognostic factors and the NDI. RESULTS: Among the 1508 patients undergoing surgery for myelopathy, 1248 (82.7%) were followed for either 3 or 12 months. Of these, 317 (25.4%) were classified to belong to the worsening group according to the mean NDI percentage change cutoff of 3.3. Multivariable analyses showed that smoking (odds ratio [OR] 3.4: 95% CI 1.2-9.5: P < .001), low educational level (OR 2.5: 95% CI 1.0-6.5: P < .001), and American Society of Anesthesiologists grade >II (OR 2.2: 95% CI 0.7-5.6: P = .004) were associated with worsening. Patients with more severe neck pain (OR 0.8: 95% CI 0.7-1.0: P = .003) and arm pain (OR 0.8: 95% CI 0.7-1.0; P = .007) at baseline were less likely to report worsening. CONCLUSION: We defined a cutoff value of 3.3 for worsening after DCM surgery using the mean NDI percentage change. The independent prognostic factors associated with worsening of pain-related disability were smoking, low educational level, and American Society of Anesthesiologists grade >II. Patients with more severe neck and arm pain at baseline were less likely to report worsening at 12 months.

Long-Term Results After Surgery for Degenerative Cervical Myelopathy.

BACKGROUND AND OBJECTIVES: Degenerative cervical myelopathy (DCM) is a frequent cause of spinal cord dysfunction, and surgical treatment is considered safe and effective. Long-term results after surgery are limited. This study investigated long-term clinical outcomes through data from the Norwegian registry for spine surgery. METHODS: Patients operated at the university hospitals serving Central and Northern Norway were approached for long-term follow-up after 3 to 8 years. The primary outcome was change in the Neck Disability Index, and the secondary outcomes were changes in the European Myelopathy Scale score, quality of life (EuroQoL EQ-5D); numeric rating scales (NRS) for headache, neck pain, and arm pain; and perceived benefit of surgery assessed by the Global Perceived Effect scale from 1 year to long-term follow-up. RESULTS: We included 144 patients operated between January 2013 and June 2018. In total, 123 participants (85.4%) provided patient-reported outcome measures (PROMs) at long-term follow-up. There was no significant change in PROMs from 1 year to long-term follow-up, including Neck Disability Index (mean 1.0, 95% CI -2.1-4.1, P = .53), European Myelopathy Scale score (mean -0.3, 95% CI -0.7-0.1, P = .09), EQ-5D index score (mean -0.02, 95% CI -0.09-0.05, P = .51), NRS neck pain (mean 0.3 95% CI -0.2-0.9, P = .22), NRS arm pain (mean -0.1, 95% CI -0.8-0.5, P = .70), and NRS headache (mean 0.4, 95% CI -0.1-0.9, P = .11). According to Global Perceived Effect assessments, 106/121 patients (87.6%) reported to be stable or improved ("complete recovery," "much better," "slightly better," or "unchanged") at long-term follow-up compared with 88.1% at 1 year. Dichotomizing the outcome data based on severity of DCM did not demonstrate significant changes either. CONCLUSION: Long-term follow-up of patients undergoing surgery for DCM demonstrates persistence of statistically significant and clinically meaningful improvement across a wide range of PROMs.

The Norwegian registry for spine surgery (NORspine): cohort profile.

PURPOSE: To review and describe the development, methods and cohort of the lumbosacral part of the Norwegian registry for spine surgery (NORspine). METHODS: NORspine was established in 2007. It is government funded, covers all providers and captures consecutive cases undergoing operations for degenerative disorders. Patients' participation is voluntary and requires informed consent. A set of baseline-, process- and outcome-variables (3 and 12 months) recommended by the International Consortium for Health Outcome Measurement is reported by surgeons and patients. The main outcome is the Oswestry disability index (ODI) at 12 months. RESULTS: We show satisfactory data quality assessed by completeness, timeliness, accuracy, relevance and comparability. The coverage rate has been 100% since 2016 and the capture rate has increased to 74% in 2021. The cohort consists of 60,647 (47.6% women) cases with mean age 55.7 years, registered during the years 2007 through 2021. The proportions > 70 years and with an American Society of Anaesthesiologists' Physical Classification System (ASA) score > II has increased gradually to 26.1% and 19.3%, respectively. Mean ODI at baseline was 43.0 (standard deviation 17.3). Most cases were operated with decompression for disc herniation (n = 26,557, 43.8%) or spinal stenosis (n = 26,545, 43.8%), and 7417 (12.2%) with additional or primary fusion. The response rate at 12 months follow-up was 71.6%. CONCLUSION: NORspine is a well-designed population-based comprehensive national clinical quality registry. The register's methods ensure appropriate data for quality surveillance and improvement, and research.

The Norwegian degenerative spondylolisthesis and spinal stenosis (NORDSTEN) study: study overview, organization structure and study population.

PURPOSE: To provide an overview of the The Norwegian Degenerative spondylolisthesis and spinal stenosis (NORDSTEN)-study and the organizational structure, and to evaluate the study population. METHODS: The NORDSTEN is a multicentre study with 10 year follow-up, conducted at 18 public hospitals. NORDSTEN includes three studies: (1) The randomized spinal stenosis trial comparing the impact of three different decompression techniques; (2) the randomized degenerative spondylolisthesis trial investigating whether decompression surgery alone is as good as decompression with instrumented fusion; (3) the observational cohort tracking the natural course of LSS in patients without planned surgical treatment. A range of clinical and radiological data are collected at defined time points. To administer, guide, monitor and assist the surgical units and the researchers involved, the NORDSTEN national project organization was established. Corresponding clinical data from the Norwegian Registry for Spine Surgery (NORspine) were used to assess if the randomized NORDSTEN-population at baseline was representative for LSS patients treated in routine surgical practice. RESULTS: A total of 988 LSS patients with or without spondylolistheses were included from 2014 to 2018. The clinical trials did not find any difference in the efficacy of the surgical methods evaluated. The NORDSTEN patients were similar to those being consecutively operated at the same hospitals and reported to the NORspine during the same time period. CONCLUSION: The NORDSTEN study provides opportunity to investigate clinical course of LSS with or without surgical interventions. The NORDSTEN-study population were similar to LSS patients treated in routine surgical practice, supporting the external validity of previously published results. TRIAL REGISTRATION: ClinicalTrials.gov; NCT02007083 10/12/2013, NCT02051374 31/01/2014 and NCT03562936 20/06/2018.

Persistent Use of Prescription Opioids Before and After Lumbar Spine Surgery: Observational Study With Prospectively Collected Data From Two Norwegian National Registries.

STUDY DESIGN: Prospective pharmacoepidemiologic study. OBJECTIVE: To investigate clinical and sociodemographic factors associated with persistent opioid use in the years following spine surgery among patients with persistent opioid use preceding lumbar spine surgery. SUMMARY OF BACKGROUND DATA: It is unknown whether successful spine surgery leads to a cessation of preoperative persistent opioid use. MATERIALS AND METHODS: Data from the Norwegian Registry for Spine Surgery and the Norwegian Prescription Database were linked for patients operated for degenerative lumbar spine disorders between 2007 and 2017. The primary outcome measure was persistent opioid use in the second year after surgery. Functional disability was measured with the Oswestry Disability Index (ODI). Factors associated with persistent opioid use in the year before, and two years following, surgery were identified using multivariable logistic regression analysis. The variables included in the analysis were selected based on their demonstrated role in prior studies. RESULTS: The prevalence of persistent opioid use was 8.7% in the year before surgery. Approximately two-thirds of patients also met the criteria for persistent opioid use the second year after surgery. Among patients who did not meet the criteria for persistent opioid use the year before surgery, 991 (3.3%) patients developed persistent opioid use in the second year following surgery. The strongest association was exhibited by high doses of benzodiazepines in the year preceding surgery (OR 1.7, 95% CI 1.26 to 2.19, P <0.001). Among patients without persistent opioid use, the most influential factor associated with new-onset persistent opioid use in the second year after surgery was the use of high doses of benzodiazepines (OR 1.8, 95% CI 1.26 to 2.44, P <0.001), high doses of z -hypnotics (OR 2.6, 95% CI 2.10 to 3.23, P <0.001) and previous surgery at the same lumbar level (OR 1.37, 95% CI 1.11 to 1.68, P =0.003). CONCLUSION: A substantial proportion of patients reported sustained opioid use after surgery. Patients with persistent opioid use before surgery should be supported to taper off opioid treatment. Special efforts appear to be required to taper off opioid use in patients using high doses of benzodiazepines. LEVEL OF EVIDENCE: 2; Prospective observational study.

Characteristics and outcomes of patients who did not respond to a national spine surgery registry.

BACKGROUND: Loss to follow-up may bias outcome assessments in medical registries. This cohort study aimed to analyze and compare patients who failed to respond with those that responded to the Norwegian Registry for Spine Surgery (NORspine). METHODS: We analyzed a cohort of 474 consecutive patients operated for lumbar spinal stenosis at four public hospitals in Norway during a two-year period. These patients reported sociodemographic data, preoperative symptoms, and Oswestry Disability Index (ODI), numerical rating scales (NRS) for back and leg pain to NORspine at baseline and 12 months postoperatively. We contacted all patients who did not respond to NORspine after 12 months. Those who responded were termed responsive non-respondents and compared to 12 months respondents. RESULTS: One hundred forty (30%) did not respond to NORspine 12 months after surgery and 123 were available for additional follow-up. Sixty-four of the 123 non-respondents (52%) responded to a cross-sectional survey done at a median of 50 (36-64) months after surgery. At baseline, non-respondents were younger 63 (SD 11.7) vs. 68 (SD 9.9) years (mean difference (95% CI) 4.7 years (2.6 to 6.7); p = < 0.001) and more frequently smokers 41 (30%) vs. 70 (21%) RR (95%CI) = 1.40 (1.01 to 1.95); p = 0.044. There were no other relevant differences in other sociodemographic variables or preoperative symptoms. We found no differences in the effect of surgery on non-respondents vs. respondents (ODI (SD) = 28.2 (19.9) vs. 25.2 (18.9), MD (95%CI) = 3.0 ( -2.1 to 8.1); p = 0.250). CONCLUSION: We found that 30% of patients did not respond to NORspine at 12 months after spine surgery. Non-respondents were somewhat younger and smoked more frequently than respondents; however, there were no differences in patient-reported outcome measures. Our findings suggest that attrition bias in NORspine was random and due to non-modifiable factors.

Impact of the number of previous lumbar operations on patient-reported outcomes after surgery for lumbar spinal stenosis or lumbar disc herniation.

Repeated lumbar spine surgery has been associated with inferior clinical outcomes. This study aimed to examine and quantify the impact of this association in a national clinical register cohort. This is a population-based study from the Norwegian Registry for Spine surgery (NORspine). We included 26,723 consecutive cases operated for lumbar spinal stenosis or lumbar disc herniation from January 2007 to December 2018. The primary outcome was the Oswestry Disability Index (ODI), presented as the proportions reaching a patient-acceptable symptom state (PASS; defined as an ODI raw score ≤ 22) and ODI raw and change scores at 12-month follow-up. Secondary outcomes were the Global Perceived Effect scale, the numerical rating scale for pain, the EuroQoL five-dimensions health questionnaire, occurrence of perioperative complications and wound infections, and working capability. Binary logistic regression analysis was conducted to examine how the number of previous operations influenced the odds of not reaching a PASS. The proportion reaching a PASS decreased from 66.0% (95% confidence interval (CI) 65.4 to 66.7) in cases with no previous operation to 22.0% (95% CI 15.2 to 30.3) in cases with four or more previous operations (p < 0.001). The odds of not reaching a PASS were 2.1 (95% CI 1.9 to 2.2) in cases with one previous operation, 2.6 (95% CI 2.3 to 3.0) in cases with two, 4.4 (95% CI 3.4 to 5.5) in cases with three, and 6.9 (95% CI 4.5 to 10.5) in cases with four or more previous operations. The ODI raw and change scores and the secondary outcomes showed similar trends. We found a dose-response relationship between increasing number of previous operations and inferior outcomes among patients operated for degenerative conditions in the lumbar spine. This information should be considered in the shared decision-making process prior to elective spine surgery.

Clinical outcomes after surgery for cervical radiculopathy performed in public and private hospitals : a nationwide relative effectiveness study.

AIMS: The number of patients undergoing surgery for degenerative cervical radiculopathy has increased. In many countries, public hospitals have limited capacity. This has resulted in long waiting times for elective treatment and a need for supplementary private healthcare. It is uncertain whether the management of patients and the outcome of treatment are equivalent in public and private hospitals. The aim of this study was to compare the management and patient-reported outcomes among patients who underwent surgery for degenerative cervical radiculopathy in public and private hospitals in Norway, and to assess whether the effectiveness of the treatment was equivalent. METHODS: This was a comparative study using prospectively collected data from the Norwegian Registry for Spine Surgery. A total of 4,750 consecutive patients who underwent surgery for degenerative cervical radiculopathy and were followed for 12 months were included. Case-mix adjustment between those managed in public and private hospitals was performed using propensity score matching. The primary outcome measure was the change in the Neck Disability Index (NDI) between baseline and 12 months postoperatively. A mean difference in improvement of the NDI score between public and private hospitals of ≤ 15 points was considered equivalent. Secondary outcome measures were a numerical rating scale for neck and arm pain and the EuroQol five-dimension three-level health questionnaire. The duration of surgery, length of hospital stay, and complications were also recorded. RESULTS: The mean improvement from baseline to 12 months postoperatively of patients who underwent surgery in public and private hospitals was equivalent, both in the unmatched cohort (mean NDI difference between groups 3.9 points (95% confidence interval (CI) 2.2 to 5.6); p < 0.001) and in the matched cohort (4.0 points (95% CI 2.3 to 5.7); p < 0.001). Secondary outcomes showed similar results. The duration of surgery and length of hospital stay were significantly longer in public hospitals. Those treated in private hospitals reported significantly fewer complications in the unmatched cohort, but not in the matched cohort. CONCLUSION: The clinical effectiveness of surgery for degenerative cervical radiculopathy performed in public and private hospitals was equivalent 12 months after surgery.Cite this article: Bone Joint J 2023;105-B(1):64-71.

Non-respondents do not bias outcome assessment after cervical spine surgery: a multicenter observational study from the Norwegian registry for spine surgery (NORspine).

BACKGROUND: The Norwegian registry for spine surgery (NORspine) is a national clinical quality registry which has recorded more than 10,000 operations for degenerative conditions of the cervical spine since 2012. Registries are large observational cohorts, at risk for attrition bias. We therefore aimed to examine whether clinical outcomes differed between respondents and non-respondents to standardized questionnaire-based 12-month follow-up. METHODS: All eight public and private providers of cervical spine surgery in Norway report to NORspine. We included 334 consecutive patients who were registered with surgical treatment of degenerative conditions in the cervical spine in 2018 and did a retrospective analysis of prospectively collected register data and data on non-respondents' outcomes collected by telephone interviews. The primary outcome measure was patient-reported change in arm pain assessed with the numeric rating scale (NRS). Secondary outcome measures were change in neck pain assessed with the NRS, change in health-related quality of life assessed with EuroQol 5 Dimensions (EQ-5D), and patients' perceived benefit of the operation assessed by the Global Perceived Effect (GPE) scale. RESULTS: At baseline, there were few and small differences between the 238 (71.3%) respondents and the 96 (28.7%) non-respondents. We reached 76 (79.2%) non-respondents by telephone, and 63 (65.6%) consented to an interview. There was no statistically significant difference between groups in change in NRS score for arm pain (3.26 (95% CI 2.84 to 3.69) points for respondents and 2.77 (1.92 to 3.63) points for telephone interviewees) or any of the secondary outcome measures. CONCLUSIONS: The results indicate that patients lost to follow-up were missing at random. Analyses of outcomes based on data from respondents can be considered representative for the complete register cohort, if patient characteristics associated with attrition are controlled for.

Predictors for failure after surgery for lumbar spinal stenosis: a prospective observational study.

BACKGROUND/CONTEXT: Some patients do not improve after surgery for lumbar spinal stenosis (LSS), and surgical treatment implies a risk for complications and deterioration. Patient selection is of paramount importance to improve the overall clinical results and identifying predictive factors for failure is central in this work. PURPOSE: We aimed to explore predictive factors for failure and worsening after surgery for LSS. STUDY DESIGN /SETTING: Retrospective observational study on prospectively collected data from a national spine registry with a 12-month follow-up. PATIENT SAMPLE: We analyzed 11,873 patients operated for LSS between 2007 and 2017 in Norway, included in the Norwegian registry for spine surgery (NORspine). Twelve months after surgery, 8919 (75.1%) had responded. OUTCOME MEASURES: Oswestry Disability Index (ODI) 12 months after surgery. METHODS: Predictors were assessed with uni- and multivariate logistic regression, using backward conditional stepwise selection and a significance level of 0.01. Failure (ODI>31) and worsening (ODI>39) were used as dependent variables. RESULTS: Mean (95%CI) age was 66.6 (66.4-66.9) years, and 52.1% were females. The mean (95%CI) preoperative ODI score was 39.8 (39.4-40.1). All patients had decompression, and 1494 (12.6%) had an additional fusion procedure. Twelve months after surgery, the mean (95%CI) ODI score was 23.9 (23.5-24.2), and 2950 patients (33.2%) were classified as failures and 1921 (21.6%) as worse. The strongest predictors for failure were duration of back pain > 12 months (OR [95%CI]=2.24 [1.93-2.60]; p<.001), former spinal surgery (OR [95%CI]=2.21 [1.94-2.52]; p<.001) and age>70 years (OR (95%CI)=1.97 (1.69-2.30); p<.001). Socioeconomic variables increased the odds of failure (ORs between 1.36 and 1.62). The strongest predictors for worsening were former spinal surgery (OR [95%CI]=2.04 [1.77-2.36]; p<.001), duration of back pain >12 months (OR [95%CI]=1.83 [1.45-2.32]; p<.001) and age >70 years (OR [95%CI]=1.79 [1.49-2.14]; p<.001). Socioeconomic variables increased the odds of worsening (ORs between 1.33-1.67). CONCLUSIONS: After surgery for LSS, 33% of the patients reported failure, and 22% reported worsening as assessed by ODI. Preoperative duration of back pain for longer than 12 months, former spinal surgery, and age above 70 years were the strongest predictors for increased odds of failure and worsening after surgery.

Anterior surgical treatment for cervical degenerative radiculopathy: a prediction model for non-success.

PURPOSE: By using data from the Norwegian Registry for Spine Surgery, we wanted to develop and validate prediction models for non-success in patients operated with anterior surgical techniques for cervical degenerative radiculopathy (CDR). METHODS: This is a multicentre longitudinal study of 2022 patients undergoing CDR surgery and followed for 12 months to find prognostic models for non-success in neck disability and arm pain using multivariable logistic regression analysis. Model performance was evaluated by area under the receiver operating characteristic curve (AUC) and a calibration test. Internal validation by bootstrapping re-sampling with 1000 repetitions was applied to correct for over-optimism. The clinical usefulness of the neck disability model was explored by developing a risk matrix for individual case examples. RESULTS: Thirty-eight percent of patients experienced non-success in neck disability and 35% in arm pain. Loss to follow-up was 35% for both groups. Predictors for non-success in neck disability were high physical demands in work, low level of education, pending litigation, previous neck surgery, long duration of arm pain, medium-to-high baseline disability score and presence of anxiety/depression. AUC was 0.78 (95% CI, 0.75, 0.82). For the arm pain model, all predictors for non-success in neck disability, except for anxiety/depression, were found to be significant in addition to foreign mother tongue, smoking and medium-to-high baseline arm pain. AUC was 0.68 (95% CI, 0.64, 0.72). CONCLUSION: The neck disability model showed high discriminative performance, whereas the arm pain model was shown to be acceptable. Based upon the models, individualized risk estimates can be made and applied in shared decision-making with patients referred for surgical assessment.

Surgery for degenerative cervical myelopathy in patients with rheumatoid arthritis and ankylosing spondylitis: a nationwide registry-based study with patient-reported outcomes.

PURPOSE: To compare patient-reported outcomes (PROMs) following surgery for degenerative cervical myelopathy (DCM) among patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS) versus those without rheumatic diseases. METHODS: Data were obtained from the Norwegian Registry for Spine Surgery. The primary outcome was change in the Neck Disability Index (NDI) at 1 year. Secondary endpoints included the European Myelopathy Score (EMS), quality of life (EuroQoL-5D [EQ-5D]), numeric rating scales (NRS) for headache, neck pain, and arm pain, and complications. RESULTS: Among 905 participants operated between 2012 and 2018, 35 had RA or AS. There were significant improvements in all PROMs at 1 year and no statistically significant difference between the cohorts in mean change in NDI (- 0.64, 95% CI - 8.1 to 6.8, P = .372), EQ-5D (0.10, 95% CI - 0.04 to 0.24, P = .168), NRS neck pain (- 0.8, 95% CI - 2.0 to 0.4, P = .210), NRS arm pain (- 0.6, 95% CI - 1.9 to 0.7, P = .351), and NRS headache (- 0.5, 95% CI - 1.7 to 0.8, P = .460). DISCUSSION AND CONCLUSION: Our study adds to the limited available evidence that surgical treatment cannot only arrest further progression of myelopathy but also improve functional status, neurological outcomes, and quality of life in patients with rheumatic disease.

Effect of Spinal Cord Burst Stimulation vs Placebo Stimulation on Disability in Patients With Chronic Radicular Pain After Lumbar Spine Surgery: A Randomized Clinical Trial.

Importance: The use of spinal cord stimulation for chronic pain after lumbar spine surgery is increasing, yet rigorous evidence of its efficacy is lacking. Objective: To investigate the efficacy of spinal cord burst stimulation, which involves the placement of an implantable pulse generator connected to electrodes with leads that travel into the epidural space posterior to the spinal cord dorsal columns, in patients with chronic radiculopathy after surgery for degenerative lumbar spine disorders. Design, Setting, and Participants: This placebo-controlled, crossover, randomized clinical trial in 50 patients was conducted at St Olavs University Hospital in Norway, with study enrollment from September 5, 2018, through April 28, 2021. The date of final follow-up was May 20, 2022. Interventions: Patients underwent two 3-month periods with spinal cord burst stimulation and two 3-month periods with placebo stimulation in a randomized order. Burst stimulation consisted of closely spaced, high-frequency electrical stimuli delivered to the spinal cord. The stimulus consisted of a 40-Hz burst mode of constant-current stimuli with 4 spikes per burst and an amplitude corresponding to 50% to 70% of the paresthesia perception threshold. Main Outcomes and Measures: The primary outcome was difference in change from baseline in the self-reported Oswestry Disability Index (ODI; range, 0 points [no disability] to 100 points [maximum disability]; the minimal clinically important difference was 10 points) score between periods with burst stimulation and placebo stimulation. The secondary outcomes were leg and back pain, quality of life, physical activity levels, and adverse events. Results: Among 50 patients who were randomized (mean age, 52.2 [SD, 9.9] years; 27 [54%] were women), 47 (94%) had at least 1 follow-up ODI score and 42 (84%) completed all stimulation randomization periods and ODI measurements. The mean ODI score at baseline was 44.7 points and the mean changes in ODI score were -10.6 points for the burst stimulation periods and -9.3 points for the placebo stimulation periods, resulting in a mean between-group difference of -1.3 points (95% CI, -3.9 to 1.3 points; P = .32). None of the prespecified secondary outcomes showed a significant difference. Nine patients (18%) experienced adverse events, including 4 (8%) who required surgical revision of the implanted system. Conclusions and Relevance: Among patients with chronic radicular pain after lumbar spine surgery, spinal cord burst stimulation, compared with placebo stimulation, after placement of a spinal cord stimulator resulted in no significant difference in the change from baseline in self-reported back pain-related disability. Trial Registration: ClinicalTrials.gov Identifier: NCT03546738.

Is surgery for recurrent lumbar disc herniation worthwhile or futile? A single center observational study with patient reported outcomes.

Objective: To examine outcomes and complications following microdiscectomy for recurrent lumbar disc herniation. Methods: Prospectively collected data for patients operated at the Department of Neurosurgery, St. Olavs University Hospital, Norway, were obtained from the Norwegian Registry for Spine Surgery from May 2007 through July 2016. All patients underwent lumbar microdiscectomy. The primary outcome was change in the Oswestry Disability Index (ODI) at one year. Secondary endpoints were change in quality of life measured with EuroQol 5 Dimensions (EQ-5D), back and leg pain measured with numerical rating scales (NRS), complications, and duration of surgery and hospital stays. Results: 276 patients were enrolled in the study. A total of 161 patients (58.3%) completed one-year follow-up. The mean improvement in ODI at one year was 27.1 points (95% CI 23.1 to 31.0, P <0.001). The mean improvement in EQ-5D at one year of 0.47 points (95% CI 0.40-0.54, P <0.001), representing a large effect size (Cohens D â€‹= â€‹1.3). The mean improvement in back pain and leg pain NRS were 4.3 points (95% CI 2.2-3.2, P <0.001) and 3.8 points (95% CI 2.8-3.9, P <0.001), respectively. Nine patients (3.3%) experienced intraoperative complications, and 15 (5.5%) out of 160 patients reported complications within three months following hospital discharge. Conclusions: This study shows that patients operated for recurrent lumbar disc herniation in general report significant clinical improvement.

A nationwide study of patients operated for cervical degenerative disorders in public and private hospitals.

During the last decades, there has been an increase in the rate of surgery for degenerative disorders of the cervical spine and in the use of supplementary private health insurance. Still, there is limited knowledge about the differences in characteristics of patients operated in public and private hospitals. Therefore, we aimed at comparing sociodemographic-, clinical- and patient management data on patients operated for degenerative cervical radiculopathy and degenerative cervical myelopathy in public and private hospitals in Norway. This was a cross-sectional study on patients in the Norwegian Registry for Spine Surgery operated for degenerative cervical radiculopathy and degenerative cervical myelopathy between January 2012 and December 2020. At admission for surgery, we assessed disability by the following patient reported outcome measures (PROMs): neck disability index (NDI), EuroQol-5D (EQ-5D) and numerical rating scales for neck pain (NRS-NP) and arm pain (NRS-AP). Among 9161 patients, 7344 (80.2%) procedures were performed in public hospitals and 1817 (19.8%) in private hospitals. Mean age was 52.1 years in public hospitals and 49.7 years in private hospitals (P < 0.001). More women were operated in public hospitals (47.9%) than in private hospitals (31.6%) (P < 0.001). A larger proportion of patients in private hospitals had high education (≥ 4 years of college or university) (42.9% vs 35.6%, P < 0.001). Patients in public hospitals had worse disease-specific health problems than those in private hospitals: unadjusted NDI mean difference was 5.2 (95% CI 4.4 - 6.0; P < 0.001) and adjusted NDI mean difference was 3.4 (95% CI 2.5 - 4.2; P < 0.001), and they also had longer duration of symptoms (P < 0.001). Duration of surgery (mean difference 29 minutes, 95% CI 27.1 - 30.7; P < 0.001) and length of hospital stay (mean difference 2 days, 95% CI 2.3 - 2.4; P < 0.001) were longer in public hospitals. In conclusion, patients operated for degenerative cervical spine in private hospitals were healthier, younger, better educated and more often men. They also had less and shorter duration of symptoms and seemed to be managed more efficiently. Our findings indicate that access to cervical spine surgery in private hospitals could be skewed in favour of patients with higher socioeconomic status.

Surgery for degenerative cervical myelopathy in the elderly: a nationwide registry-based observational study with patient-reported outcomes.

BACKGROUND: The aim of this study was to investigate whether clinical outcomes in patients aged ≥ 70 undergoing decompressive surgery for degenerative cervical myelopathy (DCM) differ from those of younger patients (50-70 years) at 1 year. METHODS: Data were obtained from the Norwegian Registry for Spine Surgery (NORspine). Among 651 patients included, 177 (27.2%) were ≥ 70 years old. The primary outcome was change in the Neck Disability Index (NDI). Secondary outcomes were changes in the European Myelopathy Score (EMS), quality of life (EuroQoL EQ-5D), numeric rating scales (NRS) for headache, neck pain, and arm pain, and complications. RESULTS: Significant improvements in all patient-reported outcomes (PROMs) were detected for both age cohorts at 1 year. For the two age cohorts combined, there was a statistically significant improvement in the NDI score (mean 9.2, 95% CI 7.7 to 10.6, P < 0.001). There were no differences between age cohorts in mean change of NDI (- 8.9 vs. - 10.1, P = 0.48), EQ-5D (0.13 vs. 0.17, P = 0.37), or NRS pain scores, but elderly patients experienced a larger improvement in EMS (0.7 vs. 1.3, P = 0.02). A total of 74 patients (15.6%) in the younger cohort and 43 patients (24.3%) in the older cohort experienced complications or adverse effects within 3 months of surgery, mainly urinary and respiratory tract infections. CONCLUSION: Surgery for DCM was associated with significant improvement across a wide range of PROMs for both younger and elderly patients. Surgery for DCM should not be denied based on age alone.

Comparison of 3 Different Minimally Invasive Surgical Techniques for Lumbar Spinal Stenosis: A Randomized Clinical Trial.

Importance: Operations for lumbar spinal stenosis is the most often performed surgical procedure in the adult lumbar spine. This study reports the clinical outcome of the 3 most commonly used minimally invasive posterior decompression techniques. Objective: To compare the effectiveness of 3 minimally invasive posterior decompression techniques for lumbar spinal stenosis. Design, Setting, and Participants: This randomized clinical trial used a parallel group design and included patients with symptomatic and radiologically verified lumbar spinal stenosis without degenerative spondylolisthesis. Patients were enrolled between February 2014 and October 2018 at the orthopedic and neurosurgical departments of 16 Norwegian public hospitals. Statistical analysis was performed in the period from May to June 2021. Interventions: Patients were randomized to undergo 1 of the 3 minimally invasive posterior decompression techniques: unilateral laminotomy with crossover, bilateral laminotomy, and spinous process osteotomy. Main Outcomes and Measures: Primary outcome was change in disability measured with Oswestry Disability Index (ODI; range 0-100), presented as mean change from baseline to 2-year follow-up and proportions of patients classified as success (>30% reduction in ODI). Secondary outcomes were mean change in quality of life, disease-specific symptom severity measured with Zurich Claudication Questionnaire (ZCQ), back pain and leg pain on a 10-point numeric rating score (NRS), patient perceived benefit of the surgical procedure, duration of the surgical procedure, blood loss, perioperative complications, number of reoperations, and length of hospital stay. Results: In total, 437 patients were included with a median (IQR) age of 68 (62-73) years and 230 men (53%). Of the included patients, 146 were randomized to unilateral laminotomy with crossover, 142 to bilateral laminotomy, and 149 to spinous process osteotomy. The unilateral laminotomy with crossover group had a mean change of -17.9 ODI points (95% CI, -20.8 to -14.9), the bilateral laminotomy group had a mean change of -19.7 ODI points (95% CI, -22.7 to -16.8), and the spinous process osteotomy group had a mean change of -19.9 ODI points (95% CI, -22.8 to -17.0). There were no significant differences in primary or secondary outcomes among the 3 surgical procedures, except a longer duration of the surgical procedure in the bilateral laminotomy group. Conclusions and Relevance: No differences in clinical outcomes or complication rates were found among the 3 minimally invasive posterior decompression techniques used to treat patients with lumbar spinal stenosis. Trial Registration: ClinicalTrials.gov Identifier: NCT02007083.