Clinical assessment and management of lumbar spinal stenosis: clinical dilemmas and considerations for surgical referral.

Lumbar spinal stenosis is the leading indication for spine surgery in older adults. Surgery is recommended in clinical guidelines if non-surgical treatments have been provided with insufficient benefit. The difficulty for clinicians is that the current number of randomised controlled trials is low, which creates uncertainty about which treatments to provide. For non-surgical clinicians this paucity of data leads to a clinical dilemma of whether to continue managing the patient or refer to a spine surgeon. This Viewpoint aims to provide an update on the assessment of lumbar spinal stenosis, treatment recommendations, indications for referral to a spine surgeon, and current clinical dilemmas facing non-surgical clinicians and spinal surgeons.

How much change in symptoms do spinal surgeons expect following lumbar decompression and microdiscectomy?

The study aimed to determine how much change in neurogenic claudication spinal surgeons expect in patients following lumbar decompression for lumbar spine stenosis (LSS), and radicular leg pain following microdiscectomy. Secondary aims were to identify surgeons' preferences regarding surgical techniques for lumbar decompression, and their rating of the quality of current evidence for lumbar decompression. All Australian spine surgeons were invited, of whom 71 completed the survey (31% response rate). Only registered spinal surgeons were included. The online survey, administered using REDCap, included 4 sections: demographics and background; expected change in symptoms on a +/- 100% scale (-100% worst, 0% no change and 100% best possible); surgical preference; and rating of current evidence for lumbar decompression compared with other treatments. There were 71 complete responses, 76% were neurosurgeons (N = 54), predominantly male (96%; N = 68). On average, surgeons expected an 86% (median: 87%, inter-quartile range (IQR): 80%, 91%) improvement in neurogenic claudication following lumbar decompression for LSS and 89% (median: 91%, IQR: 85%, 95%) improvement in radicular pain following microdiscectomy. A multiple linear regression found no surgeon characteristics were associated with expected change following surgery. The preferred surgical technique for LSS was full laminectomy (58%; N = 41). Thirty-five percent of surgeons accurately rated the evidence supporting the superiority of lumbar decompression compared with non-surgical care for LSS as low quality. Spine surgeons expect large symptom improvements following lumbar decompression and microdiscectomy. Understanding of the current evidence was higher for lumbar decompression with fusion, than for decompression alone for LSS.

A critical appraisal of clinical practice guidelines for the treatment of lumbar spinal stenosis.

OBJECTIVE: The aim of the review was to appraise clinical practice guidelines and their recommendations for the treatment of lumbar spinal stenosis. METHODS: PubMed, Medline, CINAHL, Embase, and Cochrane Central Register of Controlled Trials were searched up until 25/01/2020 for clinical practice guidelines on the management of lumbar spinal stenosis with a systematic process to generate recommendations and were publicly available. RESULTS: Ten guidelines were included, with a total of 76 recommendations for the treatment of lumbar spinal stenosis. Only 4 of the 10 guidelines were of satisfactory methodological quality according to the AGREE II instrument. Around three-quarters of recommendations (72.4%) were presented with poor evidence, with the remaining 21 presenting (27.6%) fair evidence. No recommendation presented good evidence. Recommendations were made on four types of interventions: surgery, injections, medications, and other nonsurgical treatments, with supporting evidence similar for all four treatment types. Positive recommendations were more common for injections (12/13=92.3%) and surgery (10/15=66%) than for nonsurgical treatments (6/21=28.6%) or medications (1/27=3.75%). CONCLUSIONS: Ten guidelines on the management of lumbar spinal stenosis were identified in the systematic review, but only four were of adequate methodological quality. While the evidence underpinning the various types of interventions was similar, guidelines tended to endorse surgery and injections but not nonsurgical interventions and medicines. These results support the need for greater rigor and inclusion of steps to minimize bias in the production of guidelines.

Measurement properties of walking outcome measures for neurogenic claudication: a systematic review and meta analysis.

BACKGROUND CONTEXT: Selecting a walking outcome measure for neurogenic claudication requires knowledge of its measurement properties. PURPOSE: To systematically review and appraise the literature on the measurement properties of walking outcome measures for patients with neurogenic claudication. STUDY DESIGN: A systematic review and meta-analysis. METHODS: A systematic search was conducted on the following seven databases: PubMed, PsychINFO, Web of Science, Embase, CINAHL, MEDLINE, and Cochrane Central Register of Controlled Trials. Clinical studies that assessed a measurement property of a walking outcome measure for patients with neurogenic claudication were selected. The methodological quality of studies was assessed using the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. Measurement property results were assessed using the adapted criteria from Terwee et al. (2007). RESULTS: Twelve studies that evaluated 15 separate walking outcome measures were included. Out of the 12 studies included, half had poor methodological quality. Four measures had acceptable test-retest reliability: the self-paced walking test (intraclass correlation coefficient, or ICC was 0.98, 95% CI: 0.95-0.99), Physical Function Scale (PFS) (pooled analysis ICC = 0.79, 95% CI: 0.77-0.89), PFS walk item (ICC = 0.81, 95% CI: 0.68-0.89), and Oswestry Disability Index (ODI) walk item (ICC = 0.86, 95% CI: 0.76-0.92). Responsiveness was assessed on five walking outcome measures, and three had adequate responsiveness: the ODI walk item (Area under the Curve, or AUC, was 0.76, SD 0.15), Treadmill test (AUC = 0.70), and PFS (AUC = 0.77, SD 0.14). A meta-analysis demonstrated the PFS had adequate test retest reliability (pooled ICC = 0.79, 95% CI: 0.77-0.89) and internal consistency (pooled Cronbach's αlpha (α) = 0.84, 95% CI: 0.81-0.86), but not criterion validity (pooled correlation coefficient = -0.59, 95% CI: -0.71, -0.45). Measures that recorded adequate criterion validity were the ODI walk item (pooled correlation coefficient = -0.71, 95% CI: -0.80, -0.58), Treadmill test (pooled correlation coefficient = 0.86, 95% CI: 0.78-0.91), and self predicted walking item (pooled correlation coefficient = 0.74, 95% CI: 0.63-0.82). CONCLUSIONS: The results of our systematic review demonstrated that high-quality studies that asses the measurement properties of walking outcome measures for patients with neurogenic claudication are lacking. There was only limited evidence available for each walking measure, which prevented any single outcome from being confirmed as the gold standard measure of neurogenic claudication. Clinicians and researchers are recommended to use the self-paced walking test and ODI walk item until further evidence is available. Future research should focus on producing high-quality studies with excellent methodology and larger sample sizes.

Is postoperative intensive care unit admission a prerequisite for elective craniotomy?

OBJECT: Routine postoperative admission to the intensive care unit (ICU) is often considered a necessity in the treatment of patients following elective craniotomy but may strain already limited resources and is of unproven benefit. In this study the authors investigated whether routine postoperative admission to a regular stepdown ward is a safe alternative. METHODS: Three hundred ninety-four consecutive patients who had undergone elective craniotomy over 54 months at a single institution were retrospectively analyzed. Indications for craniotomy included tumor (257 patients) and transsphenoidal (63 patients), vascular (31 patients), ventriculostomy (22 patients), developmental (13 patients), and base of skull conditions (8 patients). Recorded data included age, operation, reason for ICU admission, medical emergency team (MET) calls, in-hospital mortality, and postoperative duration of stay. RESULTS: Three hundred forty-three patients were admitted to the regular ward after elective craniotomy, whereas there were 43 planned and 8 unplanned ICU admissions. The most common reasons for planned ICU admissions were anticipated lengthy operations (42%) and anesthetic risks (40%); causes for unplanned ICU admissions were mainly unexpected slow neurological recovery and extensive intraoperative blood loss. Of the 343 regular ward admissions, 10 (3%) required a MET call; only 3 of these MET calls occurred within the first 48 postoperative hours and did not lead to an ICU admission. The overall mortality rate in the investigated cohort was 1%, with no fatalities in patients admitted to the normal ward postoperatively. CONCLUSIONS: Routine ward admission for patients undergoing elective craniotomies with selective ICU admission appears safe; however, approximately 2% of patients may require a direct postoperative unplanned ICU admission. Patients with anticipated long operation times, extensive blood loss, and high anesthetic risks should be selected for postoperative ICU admission, but further study is needed to determine the preoperative factors that can aid in identifying and caring for these groups of patients.

Meta-analysis and use of tests of heterogeneity in neurosurgery.

The recent increase in implementation of evidence-based medicine in neurosurgery has led to an increase in awareness of the importance of meta-analysis. An integral component of meta-analysis is the test of heterogeneity. This test examines whether the apparent differences between the studies are significant enough to bias the outcome and conclusion of the meta-analysis. The author has examined four different tests of heterogeneity available in the scientific literature for binary data. In the context of neurosurgical data, the author found that Pearson's test was the most accurate in terms of Type I and Type II errors, as well as "goodness-of-fit" between the empirical distribution and approximate chi-squared distribution. Moreover, its ease of computation made this test a highly favorable test to be used in neurosurgical data analysis.

Subdural haematomas complicating insertion of the low-pressure Novus hydrocephalus valve: a simple method for intra-operative testing of the anti-siphon device.

We previously reported 52 patients with hydrocephalus who were followed up after insertion of low-pressure Novus valves. These valves have a normally open anti-siphon device (ASD) incorporated. There were no cases of subdural haematomas (SDH). Subsequently, three new patients suffered SDH after insertion of these valves. We investigated a simple method for intra-operative testing of the ASD. These new patients had their valves replaced. In the laboratory, flow rates through five valves were recorded as a function of proximal positive pressure and distal negative pressures (siphoning). The flow rates were influenced by both proximal positive and distal negative pressures. The ASD stopped flow at distal negative pressures between -40 and -60 cm H(2)O. Proximal positive pressures increased this threshold. The flow can be measured by counting drops per minute. Three valves removed from patients were functioning as expected, one had unexpectedly slow flow at very high siphoning pressure and one had unexpectedly slow flow rates. In three patients with SDH complicating low-pressure Novus valves, the valves and anti-siphon devices were functioning adequately. Using a simple device, measuring flow rates in drops per minute was reliable and reproducible.

Association between compensation status and outcome after surgery: a meta-analysis.

CONTEXT: Compensation, whether through workers' compensation or through litigation, has been associated with poor outcome after surgery; however, this association has not been examined by meta-analysis. OBJECTIVE: To investigate the association between compensation status and outcome after surgery. DATA SOURCES: We searched MEDLINE (1966-2003), EMBASE (1980-2003), CINAHL, the Cochrane Controlled Trials Register, and reference lists of retrieved articles and textbooks, and we contacted experts in the field. STUDY SELECTION: The review included any trial of surgical intervention in which compensation status was reported and results were compared according to that status. No restrictions were placed on study design, language, or publication date. Studies were selected by 2 unblinded independent reviewers. DATA EXTRACTION: Two reviewers independently extracted data on study type, study quality, surgical procedure, outcome, country of origin, length and completeness of follow-up, and compensation type. DATA SYNTHESIS: Two hundred eleven studies satisfied the inclusion criteria. Of these, 175 stated that the presence of compensation (workers' compensation with or without litigation) was associated with a worse outcome, 35 found no difference or did not describe a difference, and 1 described a benefit associated with compensation. A meta-analysis of 129 studies with available data (n = 20,498 patients) revealed the summary odds ratio for an unsatisfactory outcome in compensated patients to be 3.79 (95% confidence interval, 3.28-4.37 by random-effects model). Grouping studies by country, procedure, length of follow-up, completeness of follow-up, study type, and type of compensation showed the association to be consistent for all subgroups. CONCLUSIONS: Compensation status is associated with poor outcome after surgery. This effect is significant, clinically important, and consistent. Because data were obtained from observational studies and were not homogeneous, the summary effect should be interpreted with caution. Compensation status should be considered a potential confounder in all studies of surgical intervention. Determination of the mechanism for this association requires further study.

Estimating the annual rate of de novo multiple aneurysms: three statistical approaches.

OBJECT: Individuals with unruptured intracranial aneurysms experience a higher rate of rupture if their history includes another aneurysm that has previously bled. The authors used systematic review and metaregression to estimate the annual rate of development of second de novo aneurysms after subarachnoid hemorrhage. METHODS: This investigation included studies in which more than 300 patients with intracranial aneurysms were described, and in which the age of the patients and the proportion with multiple aneurysms were documented. Studies describing delayed follow-up angiography that was performed after treatment of aneurysms were also reviewed. Twenty studies were included in a between-study analysis. The univariate odds ratio (OR) for multiple intracranial aneurysms per year of age was 1.085 (95% confidence interval [CI] 1.015-1.165); this value was calculated using a hierarchical model for between-study heterogeneity. Five studies were included that provided age stratification. The estimated OR for multiple intracranial aneurysms per year was 1.011 (95% CI 1.005-1.018). Four follow-up studies were available. CONCLUSIONS: According to the three different approaches (study-level, patient-level, and follow-up analyses), the estimated annual rates of development of de novo aneurysms were 1.62% (95% CI 0.28-3.59%), 0.28% (95% CI 0.12-0.49%), and 0.92% (95% CI 0.64-1.25%), respectively. The estimated annual rate of development of second de novo aneurysms ranged from 0.28 to 1.62%.

A probabilistic and interactive decision-analysis system for unruptured intracranial aneurysms.

OBJECT: The goal in this study was to develop an interactive, probabilistic decision-analysis system for clinical use in the decision to treat or observe unruptured intracranial aneurysms. Further goals were to enable users of the system to adapt decision-analysis methods to individual patients and to provide a tool for interactive sensitivity analysis. METHODS: A computer program was designed to model the outcomes of treatment and observation of unruptured aneurysms. The user supplies probabilistic estimates of key parameters relating to a specific patient and nominates discount rate and quality of life adjustments. The program uses Monte Carlo discrete-event simulation methods to derive probability estimates of the outcomes of treatment and observation. Results are expressed as summary statistics and graphs. Discounted quality-adjusted life years are graphed using survival methods. Hierarchical simulations are used to enable investigators to perform probabilistic sensitivity analysis for one or multiple parameters simultaneously. The results of sensitivity analysis are expressed in graphs and as the expected value of perfect information. The system can be distributed and updated using the Internet. CONCLUSIONS: Further research is required into the benefits of clinical application of this system. Further research is also required into the optimum level of complexity of the model, into the user interface, and into how clinicians and patients are likely to interpret results. The system is easily adaptable to a range of medical decision analyses.

Computed tomographic angiography for detecting cerebral aneurysms: implications of aneurysm size distribution for the sensitivity, specificity, and likelihood ratios.

OBJECTIVE: This study examined the efficacy of computed tomographic angiography (CTA) for detection of ruptured and unruptured aneurysms after adjustment for their size distributions under various conditions of aneurysm prevalence. METHODS: A systematic review was used to estimate 1) the aneurysm size-specific sensitivity and specificity of CTA, and 2) the size distributions of ruptured and unruptured aneurysms. Probabilistic computer simulation was used to estimate the efficacy of CTA in the detection of aneurysms. RESULTS: The sensitivity of CTA ranged from 53% (95% confidence interval [CI], 44-62%) for 2-mm aneurysms to 95% (95% CI, 92-97%) for 7-mm aneurysms. The overall specificity was 98.9% (95% CI, 91.5-99.99%), but there was between-study heterogeneity. The estimated negative likelihood ratios for ruptured, unruptured, and at least 6-mm unruptured aneurysms were 0.081, 0.18, and 0.012, respectively. The positive likelihood ratio for CTA was sensitive to the pretest probability, the size of the positive finding, and the clinical context. With a small pretest probability, the positive likelihood ratio for unruptured aneurysms ranged from 15 for 2-mm aneurysms to 61 for 5-mm aneurysms. The positive likelihood ratio for ruptured aneurysms with an intermediate pretest probability (50%) ranged from 3.9 to 56 for 2- to 5-mm aneurysms. CONCLUSION: Small aneurysms detected on CTA should be investigated further unless there is a high pretest probability of a ruptured aneurysm. During screening for ruptured aneurysms, a negative CTA should be investigated further. During screening for unruptured aneurysms, a negative CTA results in a very low probability of a clinically important aneurysm.

The probability of sudden death from rupture of intracranial aneurysms: a meta-analysis.

OBJECTIVE: To estimate the proportion of patients with aneurysmal subarachnoid hemorrhage (SAH) who die before receiving medical attention. METHODS: We performed a systematic literature review. RESULTS: Eighteen population-based studies between 1965 and 2001 described the incidence of death from SAH before the patients received medical attention. The combined overall risk of sudden death was 12.4% (95% confidence interval, 11-14%). Patient level analysis was possible for two studies. No significant association between age and sudden death was identified. Aneurysms in the posterior circulation had an estimated probability of sudden death of 44.7% (95% confidence interval, 7.4-86%). Statistical sensitivity analysis was performed to examine some possible causes for the heterogeneity between the studies. Study factors statistically associated with a higher rate of sudden death include origin in England, computed tomographic scans not available for diagnosis, inclusion of patients with SAH from arteriovenous malformations, lower or not stated rate of autopsy for deaths in the community, and a higher rate of patients with confirmed aneurysms. CONCLUSION: The combined overall estimated risk of sudden death was 12.4% for aneurysmal SAH and 44.7% for posterior circulation aneurysms. However, there are several sources of heterogeneity or possible bias in the reported studies. Further information on patient and aneurysm characteristics is required.