Neurosurgery Blog


Daily bibliographic review of the Neurosurgery Department. La Fe University Hospital. Valencia, Spain

The management and outcome for patients with chronic subdural hematoma: a prospective, multicenter, observational cohort study in the United Kingdom

J Neurosurg 127:732–739, 2017

Symptomatic chronic subdural hematoma (CSDH) will become an increasingly common presentation in neurosurgical practice as the population ages, but quality evidence is still lacking to guide the optimal management for these patients. The British Neurosurgical Trainee Research Collaborative (BNTRC) was established by neurosurgical trainees in 2012 to improve research by combining the efforts of trainees in each of the United Kingdom (UK) and Ireland’s neurosurgical units (NSUs). The authors present the first study by the BNTRC that describes current management and outcomes for patients with CSDH throughout the UK and Ireland. This provides a resource both for current clinical practice and future clinical research on CSDH.

METHODS Data on management and outcomes for patients with CSDH referred to UK and Ireland NSUs were collected prospectively over an 8-month period and audited against criteria predefined from the literature: NSU mortality < 5%, NSU morbidity < 10%, symptomatic recurrence within 60 days requiring repeat surgery < 20%, and unfavorable functional status (modified Rankin Scale score of 4–6) at NSU discharge < 30%.

RESULTS: Data from 1205 patients in 26 NSUs were collected. Bur-hole craniostomy was the most common procedure (89%), and symptomatic recurrence requiring repeat surgery within 60 days was observed in 9% of patients. Criteria on mortality (2%), rate of recurrence (9%), and unfavorable functional outcome (22%) were met, but morbidity was greater than expected (14%). Multivariate analysis demonstrated that failure to insert a drain intraoperatively independently predicted recurrence and unfavorable functional outcome (p = 0.011 and p = 0.048, respectively). Increasing patient age (p < 0.00001), postoperative bed rest (p = 0.019), and use of a single bur hole (p = 0.020) independently predicted unfavorable functional outcomes, but prescription of high-flow oxygen or preoperative use of antiplatelet medications did not.

CONCLUSIONS: This is the largest prospective CSDH study and helps establish national standards. It has confirmed in a real-world setting the effectiveness of placing a subdural drain. This study identified a number of modifiable prognostic factors but questions the necessity of some common aspects of CSDH management, such as enforced postoperative bed rest. Future studies should seek to establish how practitioners can optimize perioperative care of patients with CSDH to reduce morbidity as well as minimize CSDH recurrence. The BNTRC is unique worldwide, conducting multicenter trainee-led research and audits. This study demonstrates that collaborative research networks are powerful tools to interrogate clinical research questions.

Surgical Approaches to the Temporal Horn: An Anatomic Analysis of White Matter Tract Interruption

Operative Neurosurgery 13:258–270, 2017

Surgical access to the temporal horn is necessary to treat tumors and vascular lesions, but is used mainly in patients with mediobasal temporal epilepsy. The surgical approaches to this cavity fall into 3 primary categories: lateral, inferior, and transsylvian. The current neurosurgical literature has underestimated the interruption of involved fiber bundles and the correlated clinical manifestations.

OBJECTIVE: To delineate the interruption of fiber bundles during the different approaches to the temporal horn.

METHODS:We simulated the lateral (trans-middle temporal gyrus), inferior (transparahippocampal gyrus), and transsylvian approaches in 20 previously frozen, formalin-fixed human brains (40 hemispheres). Fiber dissection was then done along the lateral and inferior aspects under the operating microscope. Each stage of dissection and its respective fiber tract interruption were defined.

RESULTS: The lateral (trans-middle temporal gyrus) approach interrupted “U” fibers, the superior longitudinal fasciculus (inferior arm), occipitofrontal fasciculus (ventral segment), uncinate fasciculus (dorsolateral segment), anterior commissure (posterior segment), temporopontine, inferior thalamic peduncle (posterior fibers), posterior thalamic peduncle (anterior portion), and tapetum fibers. The inferior (transparahippocampal gyrus) approach interrupted “U” fibers, the cingulum (inferior arm), and fimbria, and transected the hippocampal formation. The transsylvian approach interrupted “U”fibers (anterobasal region of the extreme capsule), the uncinate fasciculus (ventromedial segment), and anterior commissure (anterior segment), and transected the anterosuperior aspect of the amygdala.

CONCLUSION: White matter dissection improves our knowledge of the complex anatomy surrounding the temporal horn. Identifying the fiber bundles at risk during each surgical approach adds important information for choosing the appropriate surgical strategy.


The Impact of Intracranial Tumor Proximity to White Matter Tracts on Morbidity and Mortality

Neurosurgery 80:193–200, 2017

Using difusion tensor imaging (DTI) in neurosurgical planning allows identification of white matter tracts and has been associated with a reduction in postoperative functional deficits.
OBJECTIVE: This study explores the relationship between the lesion-to-tract distance (LTD) and postoperative morbidity and mortality in patients with brain tumors in order to evaluate the role of DTI in predicting postoperative outcomes.

METHODS: Adult patients with brain tumors (n = 60) underwent preoperative DTI. Three major white matter pathways (superior longitudinal fasciculi [SLF], cingulum, and corticospinal tract) were identified using DTI images, and the shortest LTD was measured for each tract. Postoperative morbidity and mortality information was collected from electronic medical records.

RESULTS: The ipsilesional corticospinal tract LTD and left SLF LTD were significantly associated with the occurrence rate of total postoperative motor (P = .018) and language (P < .001) deficits, respectively. The left SLF LTD was also significantly associated with the occurrence rate of new postoperative language deficits (P = .003), and the LTD threshold that best predicted this occurrence was 1 cm (P < .001). Kaplan–Meier log-rank survival analyses in patients having high-grade tumors demonstrated a significantly higher mortality for patients with a left SLF LTD <1 cm (P = .01).

CONCLUSION: Measuring tumor proximity to major white matter tracts using DTI can inform clinicians of the likelihood of postoperative functional deficits. A distance of 1 cm or less from eloquent white matter structures most significantly predicts the occurrence of new deficits with current surgical and imaging techniques.


Fluorescein sodium-guided resection of cerebral metastases

Acta Neurochir (2017) 159:363–367

Cerebral metastasis (CM) is the most common malignancy affecting the brain. In patients eligible for surgery, complete tumor removal is the most important predictor of overall survival and neurological outcome. The emergence of surgical microscopes fitted with a fluorescein-specific filter have facilitated fluorescein-guided microsurgery and identifi- cation of tumor tissue. In 2012, we started evaluating fluores- cein (FL) with the dedicated microscope filter in cerebral me- tastases (CM). After describing the treatment results of our first 30 patients, we now retrospectively report on 95 patients.

Methods: Ninety-five patients with CM of different primary cancers were included (47 women, 48 men, mean age, 60 years, range, 25–85 years); 5 mg/kg bodyweight of FL was intrave- nously injected at induction of anesthesia. A YELLOW 560-nm filter (Pentero 900, ZEISS Meditec, Germany) was used for microsurgical tumor resection and resection control. The extent of resection (EOR) was assessed by means of early postoperative contrast-enhanced MRI and the grade of fluorescent staining as described in the surgical reports. Furthermore, we evaluated information on neurological outcome and surgical complications as well as any adverse events.

Results: Ninety patients (95%) showed bright fluorescent staining that markedly enhanced tumor visibility. Five patients (5%); three with adenocarcinoma of the lung, one with melanoma of the skin, and one with renal cell carcinoma) showed insufficient FL stain- ing. Thirteen patients (14%) showed residual tumor tissue on the postoperative MRI. Additionally, the MRI of three patients did not confirm complete resection beyond doubt. Thus, gross-total resection had been achieved in 83% (n = 79) of patients. No adverse events were registered during the postoperative course.

Conclusions: FL and the YELLOW 560-nm filter are safe and feasible tools for increasing the EOR in patients with CM. Further prospective evaluation of the FL-guided technique in CM-surgery is in planning.

Agents for fluorescence-guided glioma surgery: a systematic review of preclinical and clinical results

Acta Neurochir (2017) 159:151–167

Fluorescence-guided surgery (FGS) is a technique used to enhance visualization of tumor margins in order to increase the extent of tumor resection in glioma surgery. In this paper, we systematically review all clinically tested fluorescent agents for application in FGS for glioma and all pre-clinically tested agents with the potential for FGS for glioma.

Methods: We searched the PubMed and Embase databases for all potentially relevant studies through March 2016. We assessed fluorescent agents by the following outcomes: rate of gross total resection (GTR), overall and progression-free survival, sensitivity and specificity in discriminating tumor and healthy brain tissue, tumor-to-normal ratio of fluorescent signal, and incidence of adverse events.

Results: The search strategy resulted in 2155 articles that were screened by titles and abstracts. After full-text screening, 105 articles fulfilled the inclusion criteria evaluating the following fluorescent agents: 5-aminolevulinic acid (5-ALA) (44 studies, including three randomized control trials), fluorescein (11), indocyanine green (five), hypericin (two), 5- aminofluorescein-human serum albumin (one), endogenous fluorophores (nine) and fluorescent agents in a pre-clinical testing phase (30). Three meta-analyses were also identified.

Conclusions: 5-ALA is the only fluorescent agent that has been tested in a randomized controlled trial and results in an improvement of GTR and progression-free survival in high-grade gliomas. Observational cohort studies and case series suggest similar outcomes for FGS using fluorescein. Molecular targeting agents (e.g., fluorophore/nanoparticle labeled with anti-EGFR antibodies) are still in the pre-clinical phase, but offer promising results and may be valuable future alternatives.

Syndrome of the Trephined: A Systematic Review


Neurosurgery 79:525–534, 2016

Syndrome of the trephined (SoT) is a rare, important complication of a craniectomy characterized by neurological dysfunction that improves with cranioplasty. Its varied symptoms include motor, cognitive, and language deficits. Its exact characterization appears suboptimal, with differing approaches of evaluation. Accordingly, this topic is in great need of further investigation.

OBJECTIVE: To accurately describe SoT and explore methods of an objective diagnosis/ evaluation.

METHODS: Electronic searches of PubMed, MEDLINE, Web of Knowledge, and PsycINFO databases used the key words “syndrome of the trephined” and “sinking skin flap.” Non–English-language and duplicate articles were eliminated. Title and abstract reviews were selected for relevance. Full-text reviews were selected for articles providing individual characteristics of SoT patients.

RESULTS: This review identified that SoT most often occurs in male patients (60%) at 5.1 6 10.8 months after craniectomy for neurotrauma (38%). The average reported craniectomy is 88.3 6 34.4 cm2 and usually exists with a “sunken skin flap” (93%). Symptoms most commonly include motor, cognitive, and language deficits (57%, 41%, 28%, respectively), with improvement after cranioplasty within 3.8 6 3.9 days. Functional independence with activities of daily living is achieved by 54.9% of patients after 2.9 6 3.4 months of rehabilitation. However, evaluation of SoT is inconsistent, with only 53% of reports documenting objective studies.

DISCUSSION: SoT is a variable phenomenon associated with a prolonged time to cranioplasty. Due to current weaknesses in objectivity, we hypothesize that SoT is often underdiagnosed and recommend a multifaceted approach for consistent evaluation.

CONCLUSION: SoT is a serious complication that lacks exact characterization and deserves future investigation. Improved understanding and recognition have important implications for early intervention and patient outcomes.

Resting-state functional MRI in an intraoperative MRI setting

Resting-state functional MRI in an intraoperative MRI setting-1

J Neurosurg 125:401–409, 2016

The authors’ aim in this paper is to prove the feasibility of resting-state (RS) functional MRI (fMRI) in an intraoperative setting (iRS-fMRI) and to correlate findings with the clinical condition of patients pre- and postoperatively.

Methods: Twelve patients underwent intraoperative MRI-guided resection of lesions in or directly adjacent to the central region and/or pyramidal tract. Intraoperative RS (iRS)–fMRI was performed pre- and intraoperatively and was correlated with patients’ postoperative clinical condition, as well as with intraoperative monitoring results. Independent component analysis (ICA) was used to postprocess the RS-fMRI data concerning the sensorimotor networks, and the mean z-scores were statistically analyzed.

Results: iRS-fMRI in anesthetized patients proved to be feasible and analysis revealed no significant differences in preoperative z-scores between the sensorimotor areas ipsi- and contralateral to the tumor. A significant decrease in z-score (p < 0.01) was seen in patients with new neurological deficits postoperatively. The intraoperative z-score in the hemisphere ipsilateral to the tumor had a significant negative correlation with the degree of paresis immediately after the operation (r = -0.67, p < 0.001) and on the day of discharge from the hospital (r = -0.65, p < 0.001). Receiver operating characteristic curve analysis demonstrated moderate prognostic value of the intraoperative z-score (area under the curve 0.84) for the paresis score at patient discharge.

Conclusions: The use of iRS-fMRI with ICA-based postprocessing and functional activity mapping is feasible and the results may correlate with clinical parameters, demonstrating a significant negative correlation between the intensity of the iRS-fMRI signal and the postoperative neurological changes.

Early postoperative haematomas in neurosurgery


Acta Neurochir (2016) 158:837–846

A postoperative haematoma can be a very serious complication following a neurosurgical procedure. Patients should be informed about the risks of such an event prior to surgery. From a practical point of view, it would be important to know when the patient is most likely to deteriorate and to require surgery because of a postoperative haematoma and when it might be safe to transfer the patient to the regular ward. The up-to-date studies regarding this topic are few.

Methods We therefore undertook the present retrospective study, including a cohort of all patients operated on at the Department of Neurosurgery in Lund during the years 2011– 2014, with the aim to define the time windows for clinical deterioration and reoperation, and whether risk factors such as anticoagulant agents/antiplatelet therapy, emergency versus elective surgery and abnormal coagulation blood values were present. We also defined the type of surgery resulting in postoperative haematoma and tried to find the clinical state of the patients when they deteriorated, as well as the outcome at 3 months postoperatively.

Results During the time period from June 2011 to November 2014, a total of 7,055 surgical procedures of all kinds were registered at our department. By the search for the diagnosis codes AWE00 and AWD00 (reoperation for deep haemorrhage and for superficial haemorrhage respectively), we identified 93 reoperations, meaning a percentage of 1.3 %. Thirtyfour of the reoperations were done within the first 24 h. Twenty-four patients were reoperated on >24 h but ≤72 h after the first operation. Only four patients who were initially doing well postoperatively showed a delayed clinical deterioration within the time frame from>6 h and ≤24 h postoperatively. This means that 0.06 % of the patients who were operated upon were doing well initially, being completely awake and with no new neurological deficit and no deterioration within the first 6 h postoperatively, and then deteriorated from a postoperative haematoma within the time frame of>6 h and ≤24 h postoperatively.

Conclusions We could conclude that no exact time window distinguished very early from somewhat later postoperative haematomas in our material. However, all but two patients deteriorating between 6 and 24 h after the operation had at least one of the following risk factors defined for postoperative haematoma: meningioma surgery, anticoagulant agents/antiplatelet therapy prior to surgery (including Dalteparin [Fragmin®], Enoxaparinnatrium [Klexane®], Warfarin [Waran®], ASA [Trombyl®] or ASA and caffeine [Treo®]), emergency operation, posterior fossa surgery or chronic subdural haematoma in a patient with a shunt. This material is too small to make any definitive conclusions, but a suggestion could be to include these factors when considering the transfer of a patient from the postoperative intensive care unit to the regular ward.

Current practice of external ventricular drainage: a survey among neurosurgical departments in Germany


Acta Neurochir (2016) 158:847–853

There are various recommendations, but no generally accepted guidelines, to reduce the risk of external ventricular drainage (EVD)-associated infections. The primary objective of the present study was to evaluate the current practice of EVD in a European country and to set the results in perspective to published data.

Method A standardised questionnaire prepared by the Commission of Technical Standards and Norms of the German Society of Neurosurgery was sent to 127 neurosurgical units in Germany.

Results Data were analysed from 99 out of 127 neurosurgical units which had been contacted. Overall, more than 10,000 EVD procedures appear to be performed in Germany annually. There is disagreement about the location where the EVD is inserted, and most EVDs are still inserted in the operation theatre. Most units apply subcutaneous tunnelling. Impregnated EVD catheters are used regularly in only about 20 % of units. Single-shot antibiotic prophylaxis is given in more than half of the units, while continued antibiotic prophylaxis is installed in only 15/99 units at a regular basis. There are discrepancies in the management of prolonged EVD use with regard to replacement policies. Regular cerebrospinal fluid (CSF) sampling is still performed widely. There were no statistical differences in policies with regard to academic versus non-academic units.

Conclusions This survey clearly shows that some newer recommendations drawn from published studies penetrate much slower into clinical routine, such as the use of impregnated catheters, for example. It remains unclear how different policies actually impact quality and outcome in daily routine.

Hemodynamic response during aneurysm clipping surgery among experienced neurosurgeons


Acta Neurochir (2016) 158:221–227

Neurosurgery is a challenging field associated with high levels of mental stress. The goal of this study was to investigate the hemodynamic response of experienced neurosurgeons during aneurysm clipping surgery and to evaluate whether neurosurgeons’ hemodynamic responses are associated with patients’ clinical statuses.

Methods Four vascular neurosurgeons (all male; mean age 51 ± 10 years; post-residency experience ≥7 years) were studied during 42 aneurysm clipping procedures. Blood pressure (BP) and heart rate (HR) were assessed at rest and during seven phases of surgery: before the skin incision, after craniotomy, after dural opening, after aneurysm neck dissection, after aneurysm clipping, after dural closure and after skin closure.

Results HR and BP were significantly greater during surgery relative to the rest situation (p≤ 0.03). There was a statistically significant increase in neurosurgeons’ HR (F [6, 41] = 10.88, p <0.001), systolic BP (F [6, 41] =2.97, p =0.01), diastolic BP (F [6, 41] = 2.49, p = 0.02) and mean BP (F [6, 41] = 3.36, p = 0.003) during surgery. The greatest mean HR was after aneurysm clipping, and the greatest BP was after aneurysm neck dissection. Systolic, diastolic and mean BPs were significantly greater during surgical clipping for unruptured aneurysms compared to ruptured aneurysms across all stages of surgery (p ≤ 0.002); however, after adjusting for neurosurgeon experience, the difference in BP as a function of aneurysm rupture was not significant (p>0.08). Aneurysm location, intraoperative aneurysm rupture, admission WFNS score, admission Glasgow Coma Scale scores and Fisher grade were not associated with neurosurgeons’ intraoperative HR and BP (all p > 0.07).

Conclusions Aneurysm clipping surgery is associated with significant hemodynamic system activation among experienced neurosurgeons. The greatest HR and BP were after aneurysm neck dissection and clipping. Aneurysm location and patient clinical status were not associated with intraoperative changes of neurosurgeons’ HR and BP.

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

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

Spine 2016;41:239–245

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

Neurocognitive Changes Associated With Surgical Resection of Left and Right Temporal Lobe Glioma

Temporal lobe tumor

Neurosurgery 77:777–785, 2015

Little is known regarding the neurocognitive impact of temporal lobe tumor resection.

OBJECTIVE: To clarify subacute surgery-related changes in neurocognitive functioning (NCF) in patients with left (LTL) and right (RTL) temporal lobe glioma.

METHODS: Patients with glioma in the LTL (n = 45) or RTL (n = 19) completed comprehensive pre- and postsurgical neuropsychological assessments. NCF was analyzed with 2-way mixed design repeated-measures analysis of variance, with hemisphere (LTL or RTL) as an independent between-subjects factor and pre- and postoperative NCF as a within-subjects factor.

RESULTS: About 60% of patients with LTL glioma and 40% with RTL lesions exhibited significant worsening on at least 1 NCF test. Domains most commonly impacted included verbal memory and executive functioning. Patients with LTL tumor showed greater decline than patients with RTL tumor on verbal memory and confrontation naming tests. Nonetheless, over one-third of patients with RTL lesions also showed verbal memory decline.

CONCLUSION: In patients with temporal lobe glioma, NCF decline in the subacute postoperative period is common. As expected, patients with LTL tumor show more frequent and severe decline than patients with RTL tumor, particularly on verbally mediated measures. However, a considerable proportion of patients with RTL tumor also exhibit decline across various domains, even those typically associated with left hemisphere structures, such as verbal memory. While patients with RTL lesions may show even greater decline in visuospatial memory, this domain was not assessed. Nonetheless, neuropsychological assessment can identify acquired deficits and help facilitate early intervention in patients with temporal lobe glioma.

Interhospital Transfer of Neurosurgical Patients to a High-Volume Tertiary Care Center: Opportunities for Improvement

Interhospital Transfer of Neurosurgical Patients to a High-Volume Tertiary Care Center- Opportunities for Improvement

Neurosurgery 77:200–207, 2015

Neurosurgical indications for patient transfer include absence of local or available neurosurgical coverage, subspecialty or interdisciplinary requirements, and family preference. Transfer of patients to regional centers will increase with further centralization of medical care.

OBJECTIVE: To report the transfer records of a large tertiary care center to identify trends, failures, and opportunities to improve interhospital transfer of neurosurgical patients.

METHODS: All consecutive, prospectively documented requests for interhospital patient transfer to the adult neurosurgical service of Emory University Hospitals were retrospectively identified from a centralized transfer center database for a 1-year study period.

RESULTS: Requests for neurosurgical care constituted 1323 of the 9087 calls (14.6%); 81.1% of these requests were accepted, and a total of 984 patients (74.4%) arrived at our institutions. Patients arrived from 133 unique facilities throughout a catchment area of 66 287 sq miles. Although the median travel time for transfer patients was 36 minutes, the median interval between the request and patient arrival was 4 hours 2 minutes. The most frequent diagnoses were intracranial hemorrhage (31.8%), subarachnoid hemorrhage (31.2%), and intracranial tumor (15.2%). The overall diagnostic error rate was 10.3%. Only 42.5% of patients underwent neurosurgical intervention, and 57 patients admitted to intensive care were immediately transitioned to a lower level of care.

CONCLUSION: Interhospital transfer requires a coordinated effort among hospital administrators, physicians, and staff to make complex decisions that govern this important and costly process. These data suggest common failures and numerous opportunities for improvement in transfer efficiency, diagnostic accuracy, triage, and resource allocation.

Complications and Resource Use Associated With Surgery for Chiari Malformation Type 1 in Adults


Neurosurgery 77:261–268, 2015

Outcomes research on Chiari malformation type 1 (CM-1) is impeded by a reliance on small, single-center cohorts.

OBJECTIVE: To study the complications and resource use associated with adult CM-1 surgery using administrative data.

METHODS: We used a recently validated International Classification of Diseases, Ninth Revision, Clinical Modification code algorithm to retrospectively study adult CM-1 surgeries from 2004 to 2010 in California, Florida, and New York using State Inpatient Databases. Outcomes included complications and resource use within 30 and 90 days of treatment. We used multivariable logistic regression to identify risk factors for morbidity and negative binomial models to determine risk-adjusted costs.

RESULTS: We identified 1947 CM-1 operations. Surgical complications were more common than medical complications at both 30 days (14.3% vs 4.4%) and 90 days (18.7% vs 5.0%) postoperatively. Certain comorbidities were associated with increased morbidity; for example, hydrocephalus increased the risk for surgical (odds ratio [OR] = 4.51) and medical (OR = 3.98) complications. Medical but not surgical complications were also more common in older patients (OR = 5.57 for oldest vs youngest age category) and male patients (OR = 3.19). Risk-adjusted hospital costs were $22530 at 30 days and $24852 at 90 days postoperatively. Risk-adjusted 90-day costs were more than twice as high for patients experiencing surgical ($46264) or medical ($65679) complications than for patients without complications ($18880).

CONCLUSION: Complications after CM-1 surgery are common, and surgical complications are more frequent than medical complications. Certain comorbidities and demographic characteristics are associated with increased risk for complications. Beyond harming patients, complications are also associated with substantially higher hospital costs. These results may help guide patient management and inform decision making for patients considering surgery.

Comparative effectiveness and safety of image guidance systems in neurosurgery


J Neurosurg 123:307–313, 2015

Over the last decade, image guidance systems have been widely adopted in neurosurgery. Nonetheless, the evidence supporting the use of these systems in surgery remains limited. The aim of this study was to compare simultaneously the effectiveness and safety of various image guidance systems against that of standard surgery.

Methods In this preclinical, randomized study, 50 novice surgeons were allocated to one of the following groups: 1) no image guidance, 2) triplanar display, 3) always-on solid overlay, 4) always-on wire mesh overlay, and 5) on-demand inverse realism overlay. Each participant was asked to identify a basilar tip aneurysm in a validated model head. The primary outcomes were time to task completion (in seconds) and tool path length (in mm). The secondary outcomes were recognition of an unexpected finding (i.e., a surgical clip) and subjective depth perception using a Likert scale.

Results The time to task completion and tool path length were significantly lower when using any form of image guidance compared with no image guidance (p < 0.001 and p = 0.003, respectively). The tool path distance was also lower in groups using augmented reality compared with triplanar display (p = 0.010). Always-on solid overlay resulted in the greatest inattentional blindness (20% recognition of unexpected finding). Wire mesh and on-demand overlays mitigated, but did not negate, inattentional blindness and were comparable to triplanar display (40% recognition of unexpected finding in all groups). Wire mesh and inverse realism overlays also resulted in better subjective depth perception than always-on solid overlay (p = 0.031 and p = 0.008, respectively).

Conclusions New augmented reality platforms may improve performance in less-experienced surgeons. However, all image display modalities, including existing triplanar displays, carry a risk of inattentional blindness.

Postoperative symptoms of psychosis after deep brain stimulation in patients with Parkinson’s disease

DBS 2 leads metal head holder

Neurosurg Focus 38 (6):E5, 2015

Cases of postoperative psychosis in Parkinson’s disease patients receiving deep brain stimulation (DBS) treatment have previously been published. However, the magnitude of symptom incidence and the clinical risk factors are currently unknown. This retrospective study sheds light on these issues by investigating psychosis in a group of 128 Parkinson’s disease patients who received DBS implants.

Methods A retrospective chart review was performed to obtain surgery dates, follow-up clinic visit dates, and associated stimulation parameter settings (contacts in use and the polarity of each along with stimulation voltage, frequency, and pulse width) for each patient. Unified Parkinson’s Disease Rating Scale II Thought Disorder scores, used as a clinical assessment tool to evaluate the presence of psychosis at each visit, were also collected. The data were compiled into a database and analyzed.

Results The lifetime incidence of psychosis in this cohort of patients was 28.1%. The data suggest that risk of psychosis remains fairly constant throughout the first 5 years after implantation of a DBS system and that patients older at the time of receiving the first DBS implant are not only more likely to develop psychosis, but also to develop symptoms sooner than their younger counterparts. Further analysis provides evidence that psychosis is largely independent of the clinically used electrode contact and of stimulation parameters prior to psychosis onset.

Conclusions Although symptoms of psychosis are widely seen in patients with Parkinson’s disease in the years following stimulator placement, results of the present suggest that most psychoses occurring postoperatively are likely independent of implantation and stimulation settings.

Fluorescein sodium-guided resection of cerebral metastases — experience with the first 30 patients

Fluorescein sodium-guided resection of cerebral metastases — experience with the first 30 patients

Acta Neurochir (2015) 157:899–904

Surgical resection is a key element of the multidisciplinary treatment of cerebral metastases (CMs). Recent studies have highlighted the importance of complete resection of CMs for improving recurrence-free and overall survival rates. This study presents the first data on the use of fluorescein sodium (FL) under the dedicated surgical microscope filter YELLOW560 nm (ZeissMeditec, Germany) in patients with CM.

Methods Thirty patients with CMs of different primary cancers were included (15 females, 15 males; mean age 61.1 years); 200 mg of FL was intravenously injected directly before CM resection. A YELLOW560 nm filter was used for microsurgical tumor resection and resection control. Surgical reports were evaluated regarding the degree of fluorescent staining, postoperative MRIs regarding the extent of resection [gadolinium (Gd)-enhanced T1-weighted sequence] and the postoperative courses regarding any adverse effects.

Results Most patients (90.0 %, n=27) showed bright fluorescent staining, which markedly enhanced tumor visibility. Three patients (10.0 %) (two with adenocarcinoma of the lung and one with melanoma of the skin) showed no or only insufficient FL staining. Another three patients (10.0 %) showed residual tumor tissue in the postoperative MRI examination. In two other patients, radiographic examination could not exclude the possibility of very small areas of residual tumor tissue. Thus, gross-total resection was achieved in 83.3 % (n=25) of patients. No adverse effects were registered over the postoperative course.

Conclusions FL and the YELLOW560 nm filter are safe and practical tools for the resection of CM, but further prospective research is needed to confirm that this advanced technique will improve the quality of CM resection.

Indocyanine green videoangiography methodological variations: review

Indocyanine green videoangiography methodological variations- review

Neurosurg Rev (2015) 38:49–57

Indocyanine green videoangiography (ICGVA) procedures have become widespread within the spectrum of microsurgical techniques for neurovascular pathologies.

We have conducted a review to identify and assess the impact of all of the methodological variations of conventional ICGVA applied in the field of neurovascular pathology that have been published to date in the English literature.

A total of 18 studies were included in this review, identifying four primary methodological variants compared to conventional ICGVA: techniques based on the transient occlusion, intra-arterial ICG administration via catheters, use of endoscope system with a filter to collect fluorescence of ICG, and quantitative fluorescence analysis. These variants offer some possibilities for resolving the limitations of the conventional technique (first, the vascular structure to be analyzed must be exposed and second, vascular filling with ICG follows an additive pattern) and allow qualitatively superior information to be obtained during surgery. Advantages and disadvantages of each procedure are discussed.

More case studies with a greater number of patients are needed to compare the different procedures with their gold standard, in order to establish these results consistently.

Case-control studies in neurosurgery


J Neurosurg 121:285–296, 2014

Observational studies, such as cohort and case-control studies, are valuable instruments in evidencebased medicine. Case-control studies, in particular, are becoming increasingly popular in the neurosurgical literature due to their low cost and relative ease of execution; however, no one has yet systematically assessed these types of studies for quality in methodology and reporting.

Methods. The authors performed a literature search using PubMed/MEDLINE to identify all studies that explicitly identified themselves as “case-control” and were published in the JNS Publishing Group journals (Journal of Neurosurgery, Journal of Neurosurgery: Pediatrics, Journal of Neurosurgery: Spine, and Neurosurgical Focus) or Neurosurgery. Each paper was evaluated for 22 descriptive variables and then categorized as having either met or missed the basic definition of a case-control study. All studies that evaluated risk factors for a well-defined outcome were considered true case-control studies. The authors sought to identify key features or phrases that were or were not predictive of a true case-control study. Those papers that satisfied the definition were further evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist.

Results. The search detected 67 papers that met the inclusion criteria, of which 32 (48%) represented true case-control studies. The frequency of true case-control studies has not changed with time. Use of odds ratios (ORs) and logistic regression (LR) analysis were strong positive predictors of true case-control studies (for odds ratios, OR 15.33 and 95% CI 4.52–51.97; for logistic regression analysis, OR 8.77 and 95% CI 2.69–28.56). Conversely, negative predictors included focus on a procedure/intervention (OR 0.35, 95% CI 0.13–0.998) and use of the word “outcome” in the Results section (OR 0.23, 95% CI 0.082–0.65). After exclusion of nested case-control studies, the negative correlation between focus on a procedure/intervention and true case-control studies was strengthened (OR 0.053, 95% CI 0.0064–0.44). There was a trend toward a negative association between the use of survival analysis or Kaplan-Meier curves and true case-control studies (OR 0.13, 95% CI 0.015–1.12). True case-control studies were no more likely than their counterparts to use a potential study design “expert” (OR 1.50, 95% CI 0.57–3.95). The overall average STROBE score was 72% (range 50–86%). Examples of reporting deficiencies were reporting of bias (28%), missing data (55%), and funding (44%).

Conclusions. The results of this analysis show that the majority of studies in the neurosurgical literature that identify themselves as “case-control” studies are, in fact, labeled incorrectly. Positive and negative predictors were identified. The authors provide several recommendations that may reverse the incorrect and inappropriate use of the term “case-control” and improve the quality of design and reporting of true case-control studies in neurosurgery.

The Impact of Sedation on Brain Mapping

Brain Mapping

Neurosurgery 75:117–123, 2014

During awake craniotomies, patients may either be awake for the entire duration of the surgical intervention (awake-awake-awake craniotomy, AAA) or initially sedated (asleep-awake-asleep craniotomy, SAS).

OBJECTIVE: To examine whether prior sedation in SAS may restrict brain mapping, we conducted neuropsychological tests in patients by means of a standardized anesthetic regimen comparable to an SAS.

METHODS: We prospectively examined patients undergoing surgery either under total intravenous anesthesia (TIVA) or under regional anesthesia with slight sedation (RAS). The tests included the DO40 picture-naming test, the digit span, the Regensburg Word Fluency Test, and the finger-tapping test. Each test was conducted 3 times for every patient in the TIVA and RAS groups, once before surgery and twice within about 35 minutes after the end of sedation. Patients undergoing AAA were examined preoperatively and intraoperatively.

RESULTS: In the AAA group, no significant difference was found between preoperative and intraoperative test results. In the TIVA and RAS groups, postoperative tests showed worse results than preoperative tests. In most tests, patients improved from the first to the second postoperative test.

CONCLUSION: Cognitive and motor performance were significantly influenced by prior sedation in the TIVA and RAS groups, but not in the AAA group. Therefore, prior sedation may be assumed to cause a change in the baselines, which may compromise brain mapping and thus endanger a patient’s neurological outcome in the case of an SAS.

Neurosurgery Department. “La Fe” University Hospital. Valencia, Spain


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