Towards Evidence-Based Guidelines in Neurological Surgery


Neurological surgery practice is based on the science of balancing probabilities. A variety of clinical guidance documents have influenced how we collectively practice our art since the early 20th century. The quality of the science within these guidelines varies widely, as does their utility in positively shaping our practice.

The guidelines development process in neurological surgery has evolved significantly over the last 30 yr. Historically based in expert opinion, as a specialty we have increasingly relied on objective medical evidence to guide our clinical practice. We assessed the changing practice guidelines development process and the impact of scientifically robust guidelines on patient care.

The evolution of the guidelines development process in neurological surgery was chronicled. Several subspecialty guidelines were extracted and reviewed in detail. Their impact on practice patterns was evaluated. The importance of evidence-based research and practice guidelines development was discussed.

Evidence-based practice guidelines serve to chronicle multiple acceptable treatment options and help us move towards more standardized care for specific disease processes. Theyhelprefutefalse“standardsofcare.” Guidelines-basedcaresupportedbysolidmedical evidence has the potential to streamline patient care and improve patient outcomes. The guidelines development process identifies areas, issues, and strategies for which little medical evidence exists, as well as topics that need focused scientific investigation and future study.

The production of evidence-based practice recommendations is a vital part of furthering our specialty. Guidelines development advances our science, augments the resident education process, and protects our practice from undue external influence.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Subthalamic Nucleus and Globus Pallidus Internus Deep Brain Stimulation for the Treatment of Patients With Parkinson’s Disease

Neurosurgery 82:753–756, 2018

QUESTION 1: Is bilateral subthalamic nucleus deep brain stimulation (STN DBS) more, less, or as effective as bilateral globus pallidus internus deep brain stimulation (GPi DBS) in treating motor symptoms of Parkinson’s disease, as measured by improvements in Unified Parkinson’s Disease Rating Scale, part III (UPDRS-III) scores?

RECOMMENDATION: Given that bilateral STN DBS is at least as effective as bilateral GPi DBS in treating motor symptoms of Parkinson’s disease (as measured by improvements in UPDRS-III scores), consideration can be given to the selection of either target in patients undergoing surgery to treat motor symptoms. (Level I)

QUESTION 2: Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in allowing reduction of dopaminergic medication in Parkinson’s disease?

RECOMMENDATION: When the main goal of surgery is reduction of dopaminergic medications in a patient with Parkinson’s disease, then bilateral STN DBS should be performed instead of GPi DBS. (Level I)

QUESTION 3: Is bilateral STN DBSmore, less, or as effective as bilateral GPi DBS in treating dyskinesias associated with Parkinson’s disease?

RECOMMENDATION: There is insufficient evidence to make a generalizable recommendation regarding the target selection for reduction of dyskinesias. However, when the reduction of medication is not anticipated and there is a goal to reduce the severity of “on” medication dyskinesias, the GPi should be targeted. (Level I)

QUESTION 4: Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in improving quality of life measures in Parkinson’s disease?

RECOMMENDATION:When considering improvements in quality of life in a patient undergoing DBS for Parkinson’s disease, there is no basis to recommend bilateral DBS in 1 target over the other. (Level I) QUESTION 5: Is bilateral STN DBS associated with greater, lesser, or a similar impact on neurocognitive function than bilateral GPi DBS in Parkinson disease?

RECOMMENDATION: If there is significant concern about cognitive decline, particularly in regards to processing speed and working memory in a patient undergoing DBS, then the clinician should consider using GPi DBS rather than STN DBS, while taking into consideration other goals of surgery. (Level I)

QUESTION 6: Is bilateral STN DBS associated with a higher, lower, or similar risk of mood disturbance than GPi DBS in Parkinson’s disease?

RECOMMENDATION: If there is significant concern about the risk of depression in a patient undergoing DBS, then the clinician should consider using pallidal rather than STN stimulation, while taking into consideration other goals of surgery. (Level I)

QUESTION 7: Is bilateral STN DBS associated with a higher, lower, or similar risk of adverse events compared to GPi DBS in Parkinson’s disease?

RECOMMENDATION: There is insufficient evidence to recommend bilateral DBS in 1 target over the other in order to minimize the risk of surgical adverse events.

The full guideline can be found at: parkinsons-disease.


Management of Odontoid Fractures in the Elderly

Neurosurgery 82:419–430, 2018

Odontoid fractures are the most common fracture of the axis and the most common cervical spine fracture in patients over 65. Despite their frequency, there is considerable ambiguity regarding optimal management strategies for these fractures in the elderly. Poor bone health and medical comorbidities contribute to increased surgical risk in this population; however, nonoperative management is associated with a risk of nonunion or fibrous union.

We provide a review of the existing literature and discuss the classi- fication and evaluation of odontoid fractures. The merits of operative vs nonoperative management, fibrous union, and the choice of operative approach in elderly patients are discussed. A treatment algorithm is presented based on the available literature.

We believe that type I and type III odontoid fractures can be managed in a collar in most cases. Type II fractures with any additonal risk factors for nonunion (displacement, comminution, etc) should be considered for surgical management. However, the risks of surgery in an elderly population must be carefully considered on a case-by-case basis. In a frail elderly patient, a fibrous nonunion with close follow-up is an acceptable outcome. If operative management is chosen, a posterior approach is should be chosen when fracture- or patient-related factors make an anterior approach challenging.

The high levels of morbidity and mortality associated with odontoid fractures should encourage all providers to pursue medical co- management and optimization of bone health following diagnosis.

Outcome of conservative and surgical treatment of pyogenic spondylodiscitis

pyogenic spondylodiscitis

Eur Spine J (2016) 25:983–999

Spondylodiscitis is a spinal infection affecting primarily the intervertebral disk and the adjacent vertebral bodies. Currently many aspects of the treatment of pyogenic spondylodiscitis are still a matter of debate.

Purpose The aim of this study was to review the currently available literature systematically to determine the outcome of patients with pyogenic spondylodiscitis for conservative and surgical treatment strategies.

Methods A systematic electronic search of MEDLINE, EMBASE, Cochrane Collaboration, and Web of Science regarding the treatment of pyogenic spondylodiscitis was performed. Included articles were assessed on risk of bias according the Cochrane Handbook for Systematic Reviews of Interventions, and the quality of evidence and strength of recommendation was evaluated according the GRADE approach.

Results: 25 studies were included. Five studies had a high or moderate quality of evidence. One RCT suggest that 6 weeks of antibiotic treatment of pyogenic spondylodiscitis results in a similar outcome when compared to longer treatment duration. However, microorganism-specific studies suggest that at least 8 weeks of treatment is required for S. aureus and 8 weeks of Daptomycin for MRSA. The articles that described the outcome of surgical treatment strategies show that a large variety of surgical techniques can successfully treat spondylodiscitis. No additional long-term beneficial effect of surgical treatment could be shown in the studies comparing surgical versus antibiotic only treatment.

Conclusion There is a strong level of recommendation for 6 weeks of antibiotic treatment in pyogenic spondylodiscitis although this has only been shown by one recent RCT. If surgical treatment is indicated, it has been suggested by two prospective studies with strong level of recommendation that an isolated anterior approach could result in a better clinical outcome.

Optimal Timing of Surgical Decompression for Acute Traumatic Central Cord Syndrome

central cord syndrome

Neurosurgery 77:S15–S32, 2015

Traumatic central cord syndrome (TCCS) is an incomplete spinal cord injury defined by greater weakness in upper versus lower extremities, variable sensory loss, and variable bladder, bowel, and sexual dysfunction. The optimal timing of surgery for TCCS remains controversial.

OBJECTIVE: To determine whether timing of surgery for TCCS predicts neurological outcomes, length of stay, and complications.

METHODS: Five databases were searched through March 2015. Articles were appraised independently by 2 reviewers, and the evidence synthesized according to Grading of Recommendation Assessment, Development and Evaluation principles.

RESULTS: Nine studies (3 prognostic, 5 therapeutic, 1 both) satisfied inclusion criteria. Low level evidence suggests that patients operated on ,24 hours after injury exhibit significantly greater improvements in postoperative American Spinal Injury Association motor scores and the functional independence measure at 1 year than those operated on .24 hours after injury. Moderate evidence suggests that patients operated on >2 weeks after injury have a higher postoperative Japanese Orthopaedic Association score and recovery rate than those operated on >2 weeks after injury. There is insufficient evidence that lengths of hospital or intensive care unit stay differ between patients who undergo early versus delayed surgery. Furthermore, there is insufficient evidence that timing between injury and surgery predicts mortality rates or serious or minor adverse events.

CONCLUSION: Surgery for TCCS <24 hours after injury appears safe and effective. Although there is insufficient evidence to provide a clear recommendation for early surgery (<24 hours), it is preferable to operate during the first hospital admission and <2 weeks after injury.

Evidence-based management of traumatic thoracolumbar burst fractures

Thoracolumbar burst fracture

Neurosurg Focus 37 (1):E1, 2014

The overall evidence for nonoperative management of patients with traumatic thoracolumbar burst fractures is unknown. There is no agreement on the optimal method of conservative treatment. Recent randomized controlled trials that have compared nonoperative to operative treatment of thoracolumbar burst fractures without neurological deficits yielded conflicting results. By assessing the level of evidence on conservative management through validated methodologies, clinicians can assess the availability of critically appraised literature. The purpose of this study was to examine the level of evidence for the use of conservative management in traumatic thoracolumbar burst fractures.

Methods. A comprehensive search of the English literature over the past 20 years was conducted using PubMed (MEDLINE). The inclusion criteria consisted of burst fractures resulting from a traumatic mechanism, and fractures of the thoracic or lumbar spine. The exclusion criteria consisted of osteoporotic burst fractures, pathological burst fractures, and fractures located in the cervical spine. Of the studies meeting the inclusion/exclusion criteria, any study in which nonoperative treatment was used was included in this review.

Results. One thousand ninety-eight abstracts were reviewed and 447 papers met inclusion/exclusion criteria, of which 45 were included in this review. In total, there were 2 Level-I, 7 Level-II, 9 Level-III, 25 Level-IV, and 2 Level- V studies. Of the 45 studies, 16 investigated conservative management techniques, 20 studies compared operative to nonoperative treatments, and 9 papers investigated the prognosis of conservative management.

Conclusions. There are 9 high-level studies (Levels I–II) that have investigated the conservative management of traumatic thoracolumbar burst fractures. In neurologically intact patients, there is no superior conservative management technique over another as supported by a high level of evidence. The conservative technique can be based on patient and surgeon preference, comfort, and access to resources. A high level of evidence demonstrated similar functional outcomes with conservative management when compared with open surgical operative management in patients who were neurologically intact. The presence of a neurological deficit is not an absolute contraindication for conservative treatment as supported by a high level of evidence. However, the majority of the literature excluded patients with neurological deficits. More evidence is needed to further classify the appropriate burst fractures for conservative management to decrease variables that may impact the prognosis.

The diagnostic accuracy of brain microdialysis during surgery


Acta Neurochir (2013) 155:345–353

Monitoring of brain function and metabolism during surgery may be of benefit for patient outcome. Microdialysis is the only sampling technique to date that allows continuous monitoring of drug or metabolite concentrations in the extracellular fluid of multiple tissues in the brain. This qualitative systematic review aimed to determine whether microdialysis is a valid tool for detecting changes in tissue composition as would be expected upon changes in (induced) tissue metabolic composition during brain surgery.

Methods A systematic review was conducted by performing a MEDLINE search using the terms “Intraoperative Period” (Medical Subject Heading [MeSH]) OR “Surgery” [Subheading] OR “Monitoring, Intraoperative” [MeSH] AND “Microdialysis” [MeSH] AND “Brain” [MeSH]. Two reviewers independently assessed the methodological quality of the studies. For each study the grades of recommendation were determined.

Results The search strategy yielded 46 publications in Medline. Data extraction was performed on 16 studies. The methodological quality of studies was low, with overall scores of 4 or 5. A quantitative analysis could not be performed because of lack of sufficient data. A qualitative analysis was positive with regard to the detection of different states of tissue composition by microdialysis. However, the levels of recommendation on the outcome statements were low, resulting in a grade D level of recommendation on all statements.

Conclusions The available evidence for the validity of cerebral microdialysis as a diagnostic tool during brain surgery is of low scientific quality. In order to develop cerebral microdialysis as a valid instrument for monitoring of brain metabolism during surgery, standardised clinical prospective studies in homogeneous patient populations are required.

Total Disc Replacement for Chronic Discogenic Low Back Pain: A Cochrane Review


 Spine 2013 ; 38 : 24 – 36

Study Design. Systematic literature review.

Objective. To assess the effect of total disc replacement for chronic low back pain due to lumbar degenerative disc disease compared with fusion or other treatment options.

Summary of Background Data. There is an increasing use in disc replacement devices for degenerative disc disease, but their effectiveness compared with other interventions such as fusion of the motion segment or conservative treatment remains unclear.

Methods. A comprehensive search in PubMedCentral, MEDLINE, EMBASE, BIOSIS,, and FDA trials register was conducted. Randomized controlled trials comparing total disc replacement with any other intervention for degenerative disc disease were included. Risk of bias was assessed using the criteria of the Cochrane Back Review Group. Quality of evidence was graded according to the GRADE approach. Two review authors independently selected studies, assessed risk of bias, and extracted data. Results and upper bounds of confidence intervals were compared with predefined clinically relevant differences.

Results. We included 7 randomized controlled trials with a follow-up of 24 months. There is risk of bias in the included studies due to sponsoring and absence of any kind of blinding. One study compared disc replacement with rehabilitation and found a signifi cant advantage in favor of surgery, which, however, did not reach the predefi ned threshold. Six studies compared disc replacement with fusion and found that the mean improvement in visual analogue scale score of back pain was 5.2 mm higher (2 studies; 95% confidence interval 0.2–10.3) with a low quality of evidence. The improvement of Oswestry disability index score at 24 months in the disc replacement group was 4.3 points more than in the fusion group (5 studies; 95% confidence interval 1.85–6.68) with a low quality of evidence. Both upper bounds of the confidence intervals were below the predefined clinically relevant difference.

Conclusion. Although statistically significant, the differences in clinical improvement were not beyond generally accepted boundaries for clinical relevance. Prevention of adjacent level disease and/or facet joint degeneration was not properly assessed. Therefore, because we think that harm and complications may occur after some years, the spine surgery community should be prudent to adopt this technology on a large scale, despite the fact that total disc replacement seems to be effective in treating low back pain in selected patients, and in the short term is at least equivalent to fusion surgery.

Key words: s.

The natural history of intracranial meningiomas

J Neurosurg 114:1250–1256, 2011. DOI: 10.3171/2010.12.JNS101623

Despite the increased detection of incidental or small meningiomas, the lesion’s natural history is largely unknown.

Methods. One year or longer of follow-up was conducted in 244 patients with 273 meningiomas managed conservatively by a single surgeon between 2003 and 2008. Data were stratified according to age, sex, tumor location, symptoms, initial tumor diameter, calcification, MR imaging intensity, and edema. Linear tumor growth was defined as a 2-mm or larger increase in the maximum diameter in any direction of the tumor. Volumetric analysis (ImageJ version 1.43) was also conducted in 154 of 273 meningiomas for which complete radiological data were available in the form of DICOM files throughout the follow-up period. A volume increase greater than 8.2% was regarded as significant because the preliminary volumetry based on 20 randomly selected meningiomas showed that the average SD was 4.1%.

Results. Linear growth was observed in 120 tumors (44.0%) with a mean follow-up of 3.8 years. Factors related to tumor growth were age of 60 or younger (p = 0.0004), absence of calcification (p = 0.027), MR imaging T2 signal hyperintensity (p = 0.021), and edema (p = 0.018). Kaplan-Meier analysis and Cox proportional hazards regression analysis revealed that age 60 or younger (hazard ratio [HR] 1.54, 95% CI 1.05–2.30, p = 0.026), initial tumor diameter greater than 25 mm (HR 2.23, 95% CI 1.44–3.38, p = 0.0004), and the absence of calcification (HR 4.57, 95% CI 2.69–8.20, p < 0.0001) were factors associated with a short time to progression. Volumetric growth was seen in 74.0% of the cases. Factors associated with a higher annual growth rate were male sex (p = 0.0002), initial tumor diameter greater than 25 mm (p < 0.0001), MR imaging T2 signal hyperintensity (p = 0.0001), presence of symptoms (p = 0.037), and edema (p < 0.0001).

Conclusions. Although the authors could obtain variable results depending on the measurement method, the data demonstrate patients younger than 60 years of age and those with meningiomas characterized by hyperintensity on T2-weighted MR imaging, no calcification, diameter greater than 25 mm, and edema need to be observed more closely. Volumetry was more sensitive to detecting tumor growth than measuring the linear diameter.

Guidelines for the Management of Spontaneous Intracerebral Hemorrhage

Stroke. 2010;41:2108-2129. DOI: 10.1161/STR.0b013e3181ec611b

Purpose—The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of acute spontaneous intracerebral hemorrhage.

Methods—A formal literature search of MEDLINE was performed. Data were synthesized with the use of evidence tables. Writing committee members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council’s Levels of Evidence grading algorithm was used to grade each recommendation. Prerelease review of the draft guideline was performed by 6 expert peer reviewers and by the members of the Stroke Council Scientific Statements Oversight Committee and Stroke Council Leadership Committee. It is intended that this guideline be fully updated in 3 years’ time.

Results—Evidence-based guidelines are presented for the care of patients presenting with intracerebral hemorrhage. The focus was subdivided into diagnosis, hemostasis, blood pressure management, inpatient and nursing management, preventing medical comorbidities, surgical treatment, outcome prediction, rehabilitation, prevention of recurrence, and future considerations.

Conclusions—Intracerebral hemorrhage is a serious medical condition for which outcome can be impacted by early, aggressive care. The guidelines offer a framework for goal-directed treatment of the patient with intracerebral hemorrhage.

Complications in spine surgery. A review

J Neurosurg Spine 13:144–157, 2010.DOI: 10.3171/2010.3.SPINE09369

The overall incidence of complications or adverse events in spinal surgery is unknown. Both prospective and retrospective analyses have been performed, but the results have not been critically assessed. Procedures for different regions of the spine (cervical and thoracolumbar) and the incidence of complications for each have been reported but not compared. Authors of previous reports have concentrated on complications in terms of their incidence relevant to healthcare providers: medical versus surgical etiology and the relevance of perioperative complications to perioperative events. Few authors have assessed complication incidence from the patient’s perspective. In this report the authors summarize the spine surgery complications literature and address the effect of study design on reported complication incidence.

Methods. A systematic evidence-based review was completed to identify within the published literature complication rates in spinal surgery. The MEDLINE database was queried using the key words “spine surgery” and “complications.” This initial search revealed more than 700 articles, which were further limited through an exclusion process. Each abstract was reviewed and papers were obtained. The authors gathered 105 relevant articles detailing 80 thoracolumbar and 25 cervical studies. Among the 105 articles were 84 retrospective studies and 21 prospective studies. The authors evaluated the study designs and compared cervical, thoracolumbar, prospective, and retrospective studies as well as the durations of follow-up for each study.

Results. In the 105 articles reviewed, there were 79,471 patients with 13,067 reported complications for an overall complication incidence of 16.4% per patient. Complications were more common in thoracolumbar (17.8%) than cervical procedures (8.9%; p < 0.0001, OR 2.23). Prospective studies yielded a higher incidence of complications (19.9%) than retrospective studies (16.1%; p < 0.0001, OR 1.3). The complication incidence for prospective thoracolumbar studies (20.4%) was greater than that for retrospective series (17.5%; p < 0.0001). This difference between prospective and retrospective reviews was not found in the cervical studies. The year of study publication did not correlate with the complication incidence, although the duration of follow-up did correlate with the complication incidence (p = 0.001).

Conclusions. Retrospective reviews significantly underestimate the overall incidence of complications in spine surgery. This analysis is the first to critically assess differing complication incidences reported in prospective and retrospective cervical and thoracolumbar spine surgery studies

Meningiomas in the elderly, the surgical benefit and a new scoring system

Acta Neurochir (2010) 152:87–97 DOI 10.1007/s00701-009-0552-6

Objective The purpose of the study was to define and identify prognostic indicators within an elderly population of patients suffering from intracranial meningiomas. The clinical presentation of the patient with meningioma is diverse, manifesting as a different clinical entity in the elderly patient compared to a similar type of tumor in a young patient.

Methods Two hundred fifty patients aged over 65 years admitted to RAMBAM Medical Center with meningiomas from 1995–2005 were characterized. We report the present- ing symptoms, chronic illnesses, perioperative and long- term follow-up results for a 5-year period.

Results Based on univariate and multivariate analysis, significant prognostic indicators were identified and were implemented into a new geriatric scoring system (GSS) including tumor size and location, peritumoral edema, neurological deficits, Karnofsky score (Clancey J Neurosci Nurs 27:220, 1995; Crooks et al. J Gerontol 46:M139– M144, 1991), and associated diabetes, hypertension or lung disease. Seven outcome parameters were retrospectively tested using the scoring system, namely mortality, Barthel Index score (Mahoney and Barthel Md State Med J 14:61–65, 1965), Karnofsky score and consciousness expressed by the Glasgow Coma Scale score (Jennett and Bond Lancet 1:480–484, 1975) 5 years after surgery, as well as recurrence within and beyond 12 months. Age proved to inversely correlate with outcome. Morbidity and mortality were significantly lower in women. The extent of surgical resection (Simpson J Neurol Neurosurg Psychiatry 20:22–39, 1957) had no influence on function- al outcome, although radical resection was associated with significantly lower mortality. Generally, a GSS score higher than 14 was associated with a significantly more favorable outcome.

Conclusion The present results suggest that common experience-based considerations may be optimized and implemented into a simple scoring system that in turn may allow for outcome prediction and evidence-based decision making.