Clemens Weber

The Risk of Getting Worse: Surgically Acquired Deficits, Perioperative Complications, and Functional Outcomes After Primary Resection of Glioblastoma

OBJECTIVE Gross total resection (GTR) prolongs survival but is unfortunately not achievable in the majority of patients with glioblastoma multiforme (GBM). Cytoreductive debulkings may relieve symptoms of mass effect, but it is unknown how long such effects sustain and to what degree the potential benefits exceed risks. We explore the impact of surgical morbidity on functional outcome and survival in unselected GBM patients. METHODS We retrospectively included 144 consecutive adult patients operated on for primary GBM at a single institution between 2004 and 2009. Reporting of adverse events was done in compliance with Good Clinical Practice Guidelines. RESULTS A total of 141 (98%) operations were resections and 3 (2%) were biopsies. A decrease in Karnofsky performance status (KPS) scores was observed in 39% of patients after 6 weeks. There was a significant decrease between pre- and postoperative KPS scores (P < 0.001). Twenty-two (15.3%) patients had surgically acquired neurological deficits. Among patients who underwent surgical resection, those with surgically acquired neurological deficits were less likely to receive radiotherapy (P < 0.001), normofractioned radiotherapy (P = 0.010), and chemotherapy (P = 0.003). Twenty-eight (19.4%) patients had perioperative complications. Among patients who underwent surgical resection, those with perioperative complications were less likely to receive normofractioned radiotherapy (P = 0.010) and chemotherapy (P = 0.009). Age (P = 0.019), surgically acquired neurological deficits (P < 0.001), and surgical complications (P = 0.006) were significant predictors for worsened functional outcome after 6 weeks. GTR (P = 0.035), perioperative complications (P = 0.008), radiotherapy (P < 0.001), and chemotherapy (P = 0.045) were independent factors associated with 12-month postoperative survival. CONCLUSION Patients with perioperative complications and surgically acquired deficits were less likely to receive adjuvant therapy. While cytoreductive debulking may not improve survival in GBM, it may decrease the likelihood of patients receiving adjuvant therapy that does.

Minimally invasive decompression versus open laminectomy for central stenosis of the lumbar spine: pragmatic comparative effectiveness study

Objective To test the equivalence for clinical effectiveness between microdecompression and laminectomy in patients with central lumbar spinal stenosis. Design Multicentre observational study. Setting Prospective data from the Norwegian Registry for Spine Surgery. Participants 885 patients with central stenosis of the lumbar spine who underwent surgery at 34 Norwegian orthopaedic or neurosurgical departments. Patients were treated from October 2006 to December 2011. Interventions Laminectomy and microdecompression. Main outcome measures The primary outcome was change in Oswestry disability index score one year after surgery. Secondary endpoints were quality of life (EuroQol EQ-5D), perioperative complications, and duration of surgical procedures and hospital stays. A blinded biostatistician performed predefined statistical analyses in unmatched and propensity matched cohorts. Results The study was powered to detect a difference between the groups of eight points on the Oswestry disability index at one year. 721 patients (81%) completed the one year follow-up. Equivalence between microdecompression and laminectomy was shown for the Oswestry disability index (difference 1.3 points, 95% confidence interval −1.36 to 3.92, P<0.001 for equivalence). Equivalence was confirmed in the propensity matched cohort and full information regression analyses. No difference was found between groups in quality of life (EQ-5D) one year after surgery. The number of patients with complications was higher in the laminectomy group (15.0% v 9.8%, P=0.018), but after propensity matching for complications the groups did not differ (P=0.23). The duration of surgery for single level decompression was shorter in the microdecompression group (difference 11.2 minutes, 95% confidence interval 4.9 to 17.5, P<0.001), but after propensity matching the groups did not differ (P=0.15). Patients in the microdecompression group had shorter hospital stays, both for single level decompression (difference 1.5 days, 95% confidence interval 1.7 to 2.6, P<0.001) and two level decompression (0.8 days, 1.0 to 2.2, P=0.003). Conclusion At one year the effectiveness of microdecompression is equivalent to laminectomy in the surgical treatment of central stenosis of the lumbar spine. Favourable outcomes were observed at one year in both treatment groups. Trial registration ClinicalTrials.gov NCT02006901.

Does Obesity Affect Outcomes After Decompressive Surgery for Lumbar Spinal Stenosis? A Multicenter, Observational, Registry-Based Study.

OBJECTIVE To evaluate the association between obesity and outcomes 1 year after laminectomy or microdecompression for lumbar spinal stenosis (LSS). METHODS The primary outcome measure was the Oswestry Disability Index (ODI). Obesity was defined as body mass index (BMI) ≥ 30. Prospective data were retrieved from the Norwegian Registry for Spine Surgery. RESULTS For all patients (n = 1473) the mean improvement in ODI at 1 year was 16.7 points (95% CI 15.7-17.7, P < 0.001). The improvement in ODI was 17.5 points in nonobese and 14.3 points in obese patients (P = 0 .007). Obese patients were less likely to achieve a minimal clinically important difference in ODI (defined as ≥ 8 points improvement) than nonobese patients (62.2 vs. 70.3%, P = 0.013). Obesity was identified as a negative predictor for ODI improvement in a multiple regression analysis (P < 0.001). Nonobese patients experienced more improvement in both back pain (0.7 points, P = 0.002) and leg pain (0.8 points, P = 0.001) measured by numeric rating scales. Duration of surgery was shorter for nonobese patients for both single- (79 vs. 89 minutes, P = 0.001) and 2-level (102 vs. 114 minutes, P = 0.004) surgery. There was no difference in complication rates (10.4% vs. 10.8%, P = 0.84). There was no difference in length of hospital stays for single- (2.7 vs. 3.0 days, P = 0.229) or 2-level (3.5 vs. 3.6 days, P = 0.704) surgery. CONCLUSIONS Both nonobese and obese patients report considerable clinical improvement 1 year after surgery for LSS, but improvement was less in obese patients. Obese patients were less likely to achieve a minimal clinically important difference.

Is There an Association Between Radiological Severity of Lumbar Spinal Stenosis and Disability, Pain, or Surgical Outcome?: A Multicenter Observational Study.

Study Design. Observational multicenter study. Objective. To evaluate if the severity of lumbar spinal stenosis (LSS) on magnetic resonance imaging (MRI) correlates with preoperative disability, pain, or surgical outcomes. Summary of Background Data. Surgeons use the morphological appearance of LSS on MRI for clinical decision making. However, the associations between radiological severity of LSS and disability, pain, or surgical outcomes remain unclear. Methods. Evaluation of severity of LSS on preoperative MRI according to the Schizas morphological classification. Patient and treatment data were retrieved from the Norwegian Registry for Spine Surgery. Preopertaive outcome measures were Oswestry disability index (ODI) and numeric rating scale (NRS) scores for back and leg pain. Postopertive outcome measures were ODI and NRS scores for back and leg pain at 1 year, changes in ODI and NRS scores after treatment, duration of surgery, length of hospital stay, and perioperative complications. Results. Of 202 patients included, 7 were found to have mild stenosis, 38 had moderate stenosis, 108 had severe stenosis, and 49 had extreme stenosis. The radiological severity of LSS was not linked to preoperative ODI (P = 0.089), NRS back pain (P = 0.273), or NRS leg pain (P = 0.282) scores. There were no differences in ODI (P = 0.933), NRS back pain (P = 0.652), or NRS leg pain (P = 0.912) scores after 1 year. The radiological severity of stenosis was not associated with change in ODI (P = 0.494), NRS back pain (P = 0.235), NRS leg pain (P = 0.790), duration of surgery (P = 0.661), length of hospital stay (P = 0.739), or perioperative complication rates (P = 0.467). Conclusion. Among patients who underwent decompressive surgery for LSS, radiological severity of stenosis was not associated with preoperative disability and pain, or clinical outcomes 1 year after surgery. In this patient group, the radiological severity of LSS has no clear clinical correlation and should therefore not be overemphasized in clinical decision making. Level of Evidence: 2

Comparative effectiveness of microdecompression and laminectomy for central lumbar spinal stenosis: study protocol for an observational study

Introduction This observational study is designed to test the equivalence between the clinical effectiveness of microdecompression and laminectomy in the surgical treatment of central lumbar spinal stenosis. Lumbar spinal stenosis is the most frequent indication for spinal surgery in the elderly, and as the oldest segment of the population continues to grow its prevalence is likely to increase. However, data on surgical outcomes are limited. Open or wide decompressive laminectomy, often combined with medial facetectomy and foraminotomy, was formerly the standard treatment. In recent years a growing tendency towards less invasive decompressive procedures has emerged. At present, many spine surgeons perform microdecompression for central lumbar spinal stenosis. Methods and analysis Prospectively registered treatment and outcome data are obtained from the Norwegian Registry for Spine Surgery. The primary outcome measure is change in Oswestry disability index between baseline and 12-month follow-up. Secondary outcome measures are changes in health-related quality of life measured by the Euro-Qol-5D between baseline and 12-month follow-up, perioperative complications, and duration of surgical procedures and length of hospital stay. Ethics and dissemination The study has been evaluated and approved by the regional committee for medical research in central Norway and all participants provided written informed consent. The findings of this study will be disseminated through peer-reviewed publications. Trial registration number Clinicaltrials.gov (NCT02006901).

Incidence Rates and Surgery of Primary Intraspinal Tumors in the Era of Modern Neuroimaging A National Population-Based Study

Study Design. Prospective national population-based cohort study. Objective. To evaluate national population-based data on histopathologically verified intraspinal tumors and explore time trends in incidence and surgery rates and associations with the increased availability of magnetic resonance imaging (MRI) during 1993 and 2011. Summary of Background Data. There is a relative lack of updated epidemiological data on primary intraspinal tumors and most previous studies do not capture the advances in diagnostics and surgical treatment in the era of modern neuroimaging. The possible effect of the increasing availability of MRI on incidence rates and clinical management of primary intraspinal tumors is not known. Methods. We included all patients with a histologically verified intraspinal tumor diagnosed between 1993 and 2011 in a population-based cohort based on data from the Cancer Registry of Norway. The incidence and surgery rates were calculated and compared with the number of available MRI scanners in Norway. Results. We identified 1104 patients diagnosed with a primary intraspinal tumor. The incidence rate based on the Norwegian population between 1993 and 2011 was 1.28 per 100,000. In 1993, there were 8 MRI scanners in Norway increasing to 125 in 2011. There seems to be a plateau in the increase in incidence rates after 2002 where the subsequent increase in the number of MRI scanners did not seem to be followed by further increases of intraspinal tumor surgery. Conclusion. The incidence rate of primary intraspinal tumors in Norway changed dramatically during the study period, stabilizing around 1.5 per 100,000 per year since 2002. There was an increase in surgery for all major subgroups. This increase in surgical activity seems to correlate with the simultaneous large increase in the availability of diagnostic magnetic resonance imaging. Level of Evidence: 2

Evidence-based clinical management and utilization of new technology in European neurosurgery.

BackgroundEvidence-based medicine (EBM) has become one of the pillars of modern patient care. However, neurosurgery has always been an experience-based and technology-driven discipline, and it remains unknown to which extent European neurosurgeons follow high-level evidence-based recommendations.MethodsWe conducted a Web-based survey with a 15-item questionnaire about evidence-based clinical management and utilization of new technology among European neurosurgeons. Two different sum scores were calculated from the questions concerning clinical practice; evidence-based treatment score and new technology score. A high evidence-based treatment score means that more clinical conditions (i.e., study questions) were managed in compliance with the available highest levels of evidence from published clinical trials. A high new technology score reflects the use of a high number of modern tools in neurosurgical practice.ResultsA total of 239 neurosurgeons from 30 different European countries answered the questionnaire. There were large variations among European neurosurgeons in providing evidence-based care and in utilization of various modern tools. There were significant regional differences in evidence-based treatment scores and modern technology scores with higher scores in northern and western Europe. High-volume institutions were not associated with better evidence-based treatment scores, but had significantly higher new technology scores. There were significantly higher new technology scores at university hospitals and a trend towards higher evidence-based treatment scores compared to other hospitals.ConclusionsClinical management in neurosurgery does not always comply with the best available evidence and there are large regional differences in clinical management and in utilization of various modern tools. The position of evidence-based medicine in European neurosurgery seems weak and this may be a threat to the quality of care.

Inter- and Intraobserver Agreement of Morphological Grading for Central Lumbar Spinal Stenosis on Magnetic Resonance Imaging.

Study Design Validation study of a morphological grading system for central lumbar spinal stenosis. Objective To evaluate and validate the inter- and intraobserver agreement of a morphological grading system for central lumbar spinal stenosis on magnetic resonance imaging between neurosurgeons and radiologists. Methods Two neurosurgeons and two radiologists independently assessed the morphological grading of lumbar spinal stenosis on pretreatment magnetic resonance imaging of 84 patients. Inter- and intrarater agreements were calculated by comparing the observers’ evaluations level to level on the grading method. The results of both clinicians were compared with the assessment of both radiologists. Results On axial magnetic resonance images, 189 lumbar disk levels were evaluated for the grade of stenosis. The interobserver agreement between the clinicians was substantial. The interobserver agreement between clinician 1 and both radiologists was substantial, and it was moderate between clinician 2 and both radiologists. The clinicians’ intraobserver agreement was almost perfect, and the radiologists’ intraobserver agreement was substantial. Conclusions The interobserver agreement of this morphological grading for lumbar spinal stenosis was high between both the clinicians and radiologists, whereas the intraobserver agreement was almost perfect. Experienced clinicians may safely evaluate lumbar magnetic resonance images using this morphological grading for central lumbar spinal stenosis.

Repeated 3.0 Tesla Magnetic Resonance Imaging After Clinically Successful Lumbar Disc Surgery.

Study Design. Prospective cohort study. Objective. To describe the naturally occurring magnetic resonance imaging (MRI) findings after successful microsurgical removal of lumbar disc herniation with repeated MRI examinations. Summary of Background Data. The interpretation of MRI after spinal surgery may be particularly challenging and image findings do not always correlate to clinical findings. Early postoperative MRI has limited value in the evaluation of patients after surgery for lumbar disc herniation. Methods. Prospective study of 30 successfully operated patients, which underwent 3.0 T MRI within 24 h after surgery for lumbar disc herniation and repeated at 6 weeks and 3 months postoperatively. Postoperative image findings (nerve root enhancement, nerve root thickening, displacement or compression of the nerve root, and residual mass size and signal) were assessed quantitatively. Inter-rater reliability was tested. Results. Inter-rater reliability between neuroradiologists was moderate for assessed MRI variables. In the immediate postoperative phase, compression or dislocation of the nerve root at the operated level was common. A residual mass at the operated level was seen in 80%, 47%, and 33% after 24 h, 6 weeks, and 3 months, respectively. Postoperative dislocation or compression of the nerve root from residual masses was seen in 67%, 24%, and 14% after 24 h, 6 weeks, and 3 months, respectively. A residual mass with a higher signal than muscle on T2-weighted images was seen in 80%, 30%, and 17% after 24 h, 6 weeks, and 3 months, respectively. Conclusion. A residual mass with compression or dislocation of the nerve root at the operated level, that disappears over 3 months, is a common MRI finding in patients successfully operated for symptomatic lumbar disc herniation. An expectant approach instead of early reoperations may perhaps be preferred in patients with residual pain and root compression due to residual masses with high T2-signal since these often seem to resolve spontaneously. Level of Evidence: 3

Decompressive surgery for lumbar spinal stenosis across the Atlantic: a comparison of preoperative MRI between matched cohorts from the US and Norway

BackgroundThere are no uniform guidelines regarding when to operate for Lumbar Spinal Stenosis (LSS). As we apply findings from clinical research from one population to the next, elucidating similarities or differences provides important context for the validity of extrapolating clinical outcomes. The aim of this study was to compare the morphological severity of lumbar spinal stenosis on preoperative MRI in patients undergoing decompressive surgery in Boston, USA, and Trondheim, Norway.MethodsIn this observational retrospective study, we compared morphological severity on MRI before surgical treatment between two propensity score-matched patient populations with single or two-level symptomatic LSS. We assessed the radiographic severity of LSS utilizing the Schizas classification (grade A to D).ResultsFollowing propensity score matching, demographics are balanced. In the Trondheim cohort, two levels decompression were present in 36.2% of the patients vs. 41.9% in Boston, (p = 0.396). There was no significant difference in grades A to D concerning central stenosis (p = 0.075). When dichotomized in mild/moderate (A/B) and severe /extreme (C/D), there were no significant differences in the rate of levels operated for high-grade stenosis (C/D), 67.6% in the Boston group compare to 78.1% in the Trondheim group (p = 0.088).ConclusionsTrondheim, Norway, and Boston, US, have similar radiographic thresholds of LSS for offering surgery.