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.

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.

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.

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.

A prognostic model for failure and worsening after lumbar microdiscectomy: a multicenter study from the Norwegian Registry for Spine Surgery.

OBJECTIVE: To develop a prognostic model for failure and worsening 1 year after surgery for lumbar disc herniation. METHODS: This multicenter cohort study included 11,081 patients operated with lumbar microdiscectomy, registered at the Norwegian Registry for Spine Surgery. Follow-up was 1 year. Uni- and multivariate logistic regression analyses were used to assess potential prognostic factors for previously defined cut-offs for failure and worsening on the Oswestry Disability Index scores 12 months after surgery. Since the cut-offs for failure and worsening are different for patients with low, moderate, and high baseline ODI scores, the multivariate analyses were run separately for these subgroups. Data were split into a training (70%) and a validation set (30%). The model was developed in the training set and tested in the validation set. A prediction (%) of an outcome was calculated for each patient in a risk matrix. RESULTS: The prognostic model produced six risk matrices based on three baseline ODI ranges (low, medium, and high) and two outcomes (failure and worsening), each containing 7 to 11 prognostic factors. Model discrimination and calibration were acceptable. The estimated preoperative probabilities ranged from 3 to 94% for failure and from 1 to 72% for worsening in our validation cohort. CONCLUSION: We developed a prognostic model for failure and worsening 12 months after surgery for lumbar disc herniation. The model showed acceptable calibration and discrimination, and could be useful in assisting physicians and patients in clinical decision-making process prior to surgery.

Surgery for herniated lumbar disc in private vs public hospitals: A pragmatic comparative effectiveness study.

BACKGROUND: There is limited evidence on the comparative performance of private and public healthcare. Our aim was to compare outcomes following surgery for lumbar disc herniation (LDH) in private versus public hospitals. METHODS: Data were obtained from the Norwegian registry for spine surgery. Primary outcome was change in Oswestry disability index (ODI) 1 year after surgery. Secondary endpoints were quality of life (EuroQol EQ-5D), back and leg pain, complications, and duration of surgery and hospital stays. RESULTS: Among 5221 patients, 1728 in the private group and 3493 in the public group, 3624 (69.4%) completed 1-year follow-up. In the private group, mean improvement in ODI was 28.8 points vs 32.3 points in the public group (mean difference - 3.5, 95% CI - 5.0 to - 1.9; P for equivalence < 0.001). Equivalence was confirmed in a propensity-matched cohort and following mixed linear model analyses. There were differences in mean change between the groups for EQ-5D (mean difference - 0.05, 95% CI - 0.08 to - 0.02; P = 0.002) and back pain (mean difference - 0.2, 95% CI - 0.2, - 0.4 to - 0.004; P = 0.046), but after propensity matching, the groups did not differ. No difference was found between the two groups for leg pain. Complication rates was lower in the private group (4.5% vs 7.2%; P < 0.001), but after propensity matching, there was no difference. Patients operated in private clinics had shorter duration of surgery (48.4 vs 61.8 min) and hospital stay (0.7 vs 2.2 days). CONCLUSION: At 1 year, the effectiveness of surgery for LDH was equivalent in private and public hospitals.

Criteria for failure and worsening after surgery for lumbar disc herniation: a multicenter observational study based on data from the Norwegian Registry for Spine Surgery.

PURPOSE: In clinical decision-making, it is crucial to discuss the probability of adverse outcomes with the patient. A large proportion of the outcomes are difficult to classify as either failure or success. Consequently, cutoff values in patient-reported outcome measures (PROMs) for "failure" and "worsening" are likely to be different from those of "non-success". The aim of this study was to identify dichotomous cutoffs for failure and worsening, 12 months after surgical treatment for lumbar disc herniation, in a large registry cohort. METHODS: A total of 6840 patients with lumbar disc herniation were operated and followed for 12 months, according to the standard protocol of the Norwegian Registry for Spine Surgery (NORspine). Patients reporting to be unchanged or worse on the Global Perceived Effectiveness (GPE) scale at 12-month follow-up were classified as "failure", and those considering themselves "worse" or "worse than ever" after surgery were classified as "worsening". These two dichotomous outcomes were used as anchors in analyses of receiver operating characteristics (ROC) to define cutoffs for failure and worsening on commonly used PROMs, namely, the Oswestry Disability Index (ODI), the EuroQuol 5D (EQ-5D), and Numerical Rating Scales (NRS) for back pain and leg pain. RESULTS: "Failure" after 12 months for each PROM, as an insufficient improvement from baseline, was (sensitivity and specificity): ODI change <13 (0.82, 0.82), ODI% change <33% (0.86, 0.86), ODI final raw score >25 (0.89, 0.81), NRS back-pain change <1.5 (0.74, 0.86), NRS back-pain % change <24 (0.85, 0.81), NRS back-pain final raw score >5.5 (0.81, 0.87), NRS leg-pain change <1.5 (0.81, 0.76), NRS leg-pain % change <39 (0.86, 0.81), NRS leg-pain final raw score >4.5 (0.91, 0.85), EQ-5D change <0.10 (0.76, 0.83), and EQ-5D final raw score >0.63 (0.81, 0.85). Both a final raw score >48 for the ODI and an NRS >7.5 were indicators for "worsening" after 12 months, with acceptable accuracy. CONCLUSION: The criteria with the highest accuracy for defining failure and worsening after surgery for lumbar disc herniation were an ODI percentage change score <33% for failure and a 12-month ODI raw score >48. These cutoffs can facilitate shared decision-making among doctors and patients, and improve quality assessment and comparison of clinical outcomes across surgical units. In addition to clinically relevant improvements, we propose that rates of failure and worsening should be included in reporting from clinical trials.

The Norwegian Cervical Arthroplasty Trial (NORCAT): 2-year clinical outcome after single-level cervical arthroplasty versus fusion-a prospective, single-blinded, randomized, controlled multicenter study.

PURPOSE: Standard surgical treatment for symptomatic cervical disc disease has been discectomy and fusion, but the use of arthroplasty, designed to preserve motion, has increased, and most studies report clinical outcome in its favor. Few of these trials, however, blinded the patients. We, therefore, conducted the Norwegian Cervical Arthroplasty Trial, and present 2-year clinical outcome after arthroplasty or fusion. METHODS: This multicenter trial included 136 patients with single-level cervical disc disease. The patients were randomized to arthroplasty or fusion, and blinded to the treatment modality. The surgical team was blinded to randomization until nerve root decompression was completed. Primary outcome was the self-rated Neck Disability Index. Secondary outcomes were the numeric rating scale for pain and quality of life questionnaires Short Form-36 and EuroQol-5Dimension-3 Level. RESULTS: There was a significant improvement in the primary and all secondary outcomes from baseline to 2-year follow-up for both arthroplasty and fusion (P < 0.001), and no observed significant between-group differences at any follow-up times. However, linear mixed model analyses, correcting for baseline values, dropouts and missing data, revealed a difference in Neck Disability Index (P = 0.049), and arm pain (P = 0.027) in favor of fusion at 2 years. The duration of surgery was longer (P < 0.001), and the frequency of reoperations higher (P = 0.029) with arthroplasty. CONCLUSION: The present study showed excellent clinical results and no significant difference between treatments at any scheduled follow-up. However, the rate of index level reoperations was higher and the duration of surgery longer with arthroplasty. TRIAL REGISTRATION: http://www.clinicaltrials.gov NCT 00735176.19.

Risk factors for surgical site infections among 1,772 patients operated on for lumbar disc herniation: a multicentre observational registry-based study.

BACKGROUND: There are no previous studies evaluating risk factors for surgical site infections (SSIs) and the effectiveness of prophylactic antibiotic treatment (PAT), specifically for patients operated on for lumbar disc herniation. METHOD: This observational multicentre study comprises a cohort of 1,772 consecutive patients operated on for lumbar disc herniation without laminectomy or fusion at 23 different surgical units in Norway. The patients were interviewed about SSIs according to a standardised questionnaire at 3 months' follow-up. RESULTS: Three months after surgery, 2.3% of the patients had an SSI. Only no PAT (OR = 5.3, 95% CI = 2.2-12.7, p< 0.001) and longer duration of surgery than the mean time (68 min) (OR = 2.8, 95% CI = 1.2-6.6, p = 0.02) were identified as independent risk factors for SSI. Numbers needed to have PAT to avoid one SSI was 43. CONCLUSIONS: In summary, this study clearly lends support to the use of PAT in surgery for lumbar disc herniation. Senior surgeons assisting inexperienced colleagues to avoid prolonged duration of surgery could also reduce the occurrence of SSI.

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.

Lumbar microdiscectomy for sciatica in adolescents: a multicentre observational registry-based study.

BACKGROUND: Lumbar disc herniation (LDH) is rare in the adolescent population. Factors predisposing to LDH in adolescents differ from adults with more cases being related to trauma or structural malformations. Further, there are limited data on patient-reported outcomes after lumbar microdiscectomy in adolescents. Our aim was to compare clinical outcomes at 1 year following single-level lumbar microdiscectomy in adolescents (13-19 years old) compared to younger adults (20-50 years old) with LDH. METHODS: Data were collected through the Norwegian Registry for Spine Surgery. Patients were eligible if they had radiculopathy due to LDH, underwent single-level lumbar microdiscectomy between January 2007 and May 2014, and were between 13 and 50 years old at time of surgery. The primary endpoint was change in Oswestry Disability Index (ODI) 1 year after surgery. Secondary endpoints were generic quality of life (EuroQol five dimensions [EQ-5D]), back pain numerical rating scale (NRS), leg pain NRS and complications. RESULTS: A total of 3,245 patients were included (97 patients 13-19 years old and 3,148 patients 20-50 years old). A significant improvement in ODI was observed for the whole population, but there was no difference between groups (0.6; 95% CI, -4.5 to 5.8; p = 0.811). There were no differences between groups concerning EQ-5D (-0.04; 95% CI, -0.15 to 0.07; p = 0.442), back pain NRS (-0.4; 95% CI, -1.2 to 0.4; p = 0.279), leg pain NRS (-0.4; 95% CI, -1.2 to 0.5; p = 0.374) or perioperative complications (1.0% for adolescents, 5.1% for adults, p = 0.072). CONCLUSIONS: The effectiveness and safety of single-level microdiscectomy are similar in adolescents and the adult population at 1-year follow-up.

Heterotopic ossification and clinical outcome in nonconstrained cervical arthroplasty 2 years after surgery: the Norwegian Cervical Arthroplasty Trial (NORCAT).

PURPOSE: Heterotopic ossification is a phenomenon in cervical arthroplasty. Previous reports have mainly focused on various semiconstrained devices and only a few publications have focused on ossification around devices that are nonconstrained. The purpose of this study was to assess the occurrence of heterotopic ossification around a nonconstrained cervical device and how it affects clinical outcome 2 years after surgery. METHODS: Thirty-seven patients were included from a larger cohort of a randomized controlled trial (NORCAT) which compared single-level cervical arthroplasty with fusion. The occurrence of heterotopic ossification was assessed with a CT scan and two neuroradiologists determined its degree. For grading, we used the Mehren/Suchomel classification system (grade 0-4). The patients were divided by level of ossification, low grade (0-2) or high grade (3-4), and clinical outcomes were compared. Self-rated disability for neck and arm pain (Neck Disability Index), health-related quality of life (the Short Form-36 and EuroQol-5D), and pain (the Numeric Rating Scale 11) were used as clinical outcome measures. RESULTS: Heterotopic ossification was encountered in all patients 2 years after surgery. Complete fusion (grade 4) was found in 16 % of participants, and high-grade ossification (grade 3-4) occurred in 62 %. The remaining patients were classified as having low-grade ossification (grade 2). There were no differences in the clinical outcomes of patients with low- and high-grade ossification. CONCLUSION: High-grade heterotopic ossification and spontaneous fusion 2 years after surgery were seen in a significant number of patients. However, the degree of ossification did not influence the clinical outcome.

The use of surgery for cervical degenerative disease in Norway in the period 2008-2014 : A population-based study of 6511 procedures.

BACKGROUND: The incidence rate of surgical treatment of cervical degenerative diseases (CDD) has increased in the USA and a large geographic variation has been shown. Little is known about such rates in Scandinavia and Europe. The aim of this population-based study was to (1) investigate annual incidence rates of operations performed in Norway, (2) to compare trends and variations in rates for surgical indications with and without myelopathy, and (3) to compare variations in the use of surgery between residential areas. METHODS: Patients operated for CDD and recorded in the Norwegian Patient Registry from 2008 to 2014 were evaluated according to residential areas (resident county and Regional Health Authority (RHA) area), age, gender, treating hospital, and whether myelopathy was present or not. Surgical rates were adjusted for age and gender. Data from private health care were also included. RESULTS: The annual surgical rates increased by 74.1 % from 2008 to 2014 (12.5/100,000 inhabitants). The largest increase was for surgical treatment of radiculopathy, 86.5 %. Surgical rates for CDD varied in 2014 with a ratio of 1.5 between the highest and lowest RHA and with a ratio of 2.5 between the different residential counties within one RHA. The treatment rates for myelopathy were relatively stable over time, but showed an increase of 2.1/100,000 (44.6 %) from 2013 to 2014. CONCLUSIONS: Our study shows that the rate of surgical treatment for radiculopathy due to CDD has increased substantially from 2008 to 2014 for all RHAs in Norway. The incidence rate for surgical treatment of myelopathy was more stable. An unexplained and moderate geographic variation was found.

Does daily tobacco smoking affect outcomes after microdecompression for degenerative central lumbar spinal stenosis? - A multicenter observational registry-based study.

BACKGROUND: There are limited scientific data on the impact of smoking on patient-reported outcomes following minimally invasive spine surgery. The aim of this multicenter observational study was to examine the relationship between daily smoking and patient-reported outcome at 1 year using the Oswestry Disability Index (ODI) after microdecompression for single- and two-level central lumbar spinal stenosis (LSS). Secondary outcomes were the length of hospital stays, perioperative and postoperative complications. METHOD: Data were collected through the Norwegian Registry for Spine Surgery (NORspine). RESULTS: A total of 825 patients were included (619 nonsmokers and 206 smokers). For the whole patient population there was a significant difference between preoperative ODI and ODI at 1 year (17.3 points, 95% CI 15.93-18.67, p < 0.001). There was a significant difference in ODI change at 1 year between nonsmokers and smokers (4.2 points, 95% CI 0.98-7.34, p = 0.010). At 1 year 69.6% of nonsmokers had achieved a minimal clinically important difference (≥10 points ODI improvement) compared to 60.8% of smokers (p = 0.008). There was no difference between nonsmokers and smokers in the overall complication rate (11.6% vs. 9.2%, p = 0.34). There was no difference between nonsmokers and smokers in length of hospital stays for either single-level (2.3 vs. 2.2 days, p = 0.99) or two-level (3.1 vs. 2.3 days, p = 0.175) microdecompression. Smoking was identified as a negative predictor for ODI change in a multiple regression analysis (p = 0.001) CONCLUSIONS: Nonsmokers experienced a significantly larger improvement at 1 year following microdecompression for LSS compared to smokers. Smokers were less likely to achieve a minimal clinically important difference. However, it should be emphasized that considerable improvement also was found among smokers.

Microsurgical decompression for central lumbar spinal stenosis: a single-center observational study.

OBJECTIVE: To assess outcomes and complications in patients undergoing microsurgical decompression for central lumbar spinal stenosis (LSS) without radiologic instability. METHODS: Prospective data for patients operated at the Department of Neurosurgery, St. Olavs University Hospital, Norway, were obtained from the Norwegian Registry for Spine Surgery (NORspine) from 2007 to 2012. The primary outcome was change in Oswestry disability index (ODI) at 1 year. The secondary endpoint was perioperative complications. Complications were graded according to the Ibanez classification system. RESULTS: For all patients (n = 125), the mean improvement in ODI at 1 year was 16.9 points (95% CI 13.5-20.2, p < 0.001). Seventy-six (71.7%) patients achieved a minimal clinically important difference in ODI (defined as ≥8 points improvement). The total number of complications within 3 months of surgery was 22 (17.6%). There were 14 medical and eight surgical complications, and all were Ibanez grade I or II (mild or moderate) complications. Four (3.2%) complications occurred while being admitted to the hospital and 18 (14.4%) occurred within 3 months following hospital discharge. The most common complication was urinary tract infection (n = 11, 8.8%). CONCLUSIONS: Microsurgical decompression for central LSS in the absence of radiological instability is an effective and safe treatment.

MRI evaluation of lumbar spinal stenosis: is a rapid visual assessment as good as area measurement?

BACKGROUND: Lumbar spinal stenosis (LSS) is commonly assessed on MRI by measuring dural sac cross-sectional area (DSCA). A new method, morphological grading A-D, has recently been introduced as an alternative method. OBJECTIVE: The aim of this study is to compare these two different methods for assessing LSS on MRI and study their reliability and intercorrelation. METHODS: On pretreatment MRI of 84 patients, two experienced radiologists independently classified level L2/L3, L3/L4 and L4/L5 as no, relative or significant stenosis using both methods. Agreement was analyzed by weighted Kappa. The correlation between the two methods was analysed using Spearman correlation, and visualized in a box plot. RESULTS: The interobserver agreement (95 % CI) was 0.69 (0.61-0.77) and 0.65 (0.56-0.74), respectively. The intraobserver agreements for DSCA were 0.77 (0.60-0.74) and 0.80 (0.66-0.93). On morphological grading A-D it was 0.78 (0.65-0.92) and 0.81 (0.68-0.94). The correlation coefficient between the two methods was 0.85 (p < 0.001). Grades C and D were under the limit value for significant stenosis using the DSCA. CONCLUSIONS: The study shows that the inter- and intraobserver agreements of DSCA and morphological grading A-D were acceptable and their intercorrelation is strong. Both methods may be used in the MRI evaluation of LSS.

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.