Month: August 2018

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Comparison of Multilevel Cervical Disc Replacement and Multilevel Anterior Discectomy and Fusion: A Systematic Review of Biomechanical and Clinical Evidence

World Neurosurg. (2018) 116:94-104

OBJECTIVE: The aim of this study was to comprehensively compare the clinical and biomechanical efficiency of anterior cervical discectomy and fusion (ACDF) with anterior cervical disc replacement (ACDR) for treatment of multilevel cervical disc disease using a meta-analysis and systematical review.

METHODS: A literature search was performed using PubMed, MEDLINE, EMBASE, and the Cochrane Library for articles published between January 1960 and December 2017. Both clinical and biomechanical parameters were analyzed. Statistical tests were conducted by Revman 5.3. Nineteen studies including 10 clinical studies and 9 biomechanical studies were filtered out.

RESULTS: The pooled results for clinical efficiency showed that no significant difference was observed in blood loss (P [ 0.09; mean difference [MD], 7.38; confidence interval [CI], e1.16 to 15.91), hospital stay (P[ 0.33; MD, L0.25; CI, L0.76 to 0.26), Japanese Orthopaedic Association scores (P [ 0.63; MD, L0.11; CI, L0.57 to 0.34), visual analog scale (P [ 0.08; MD, L0.50; CI, L1.06 to 0.05), and Neck Disability Index (P [ 0.33; MD, L0.55; CI, L1.65 to 0.56) between the 2 groups. Compared with ACDF, ACDR did show increased surgical time (P [ 0.03; MD, 31.42; CI, 2.71e60.14). On the other hand, ACDR showed increased index range of motion (ROM) (P < 0.00001; MD, 13.83; CI, 9.28e 18.39), lower rates of adjacent segment disease (ASD) (P [ 0.001; odds ratio [OR], 0.27; CI, 0.13e0.59), complications (P [ 0.006; OR, 0.62; CI, 0.45e0.87), and rate of subsequent surgery (P < 0.00001; OR, 0.25; CI, 0.14e0.44). As for biomechanical performance, ACDR maintained index ROM and avoided compensation in adjacent ROM and tissue pressure.

CONCLUSIONS: Multilevel ACDR may be an effective and safe alternative to ACDF in terms of clinical and biomechanical performance. However, further multicenter and prospective studies should be conducted to obtain a stronger and more reliable conclusion.

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NuNec™ Cervical Disc Arthroplasty Improves Quality of Life in Cervical Radiculopathy and Myelopathy: A 2-Year Follow-up

Neurosurgery 83:422–428, 2018

Anterior cervical disc replacement is an alternative to fusion for the treatment of selected cases of radiculopathy andmyelopathy. We report clinical and radiological outcomes after disc replacement with the NuNec™ artificial cervical disc (Pioneer (R)  Surgical Technology, Marquette, Michigan) with subgroup analysis.

OBJECTIVE: To review clinical and radiological outcomes after anterior cervical disc replacement with the NuNec™ artificial cervical disc.

METHODS: A consecutive case series of patients undergoing cervical disc replacement with the NuNec™ artificial disc was conducted. Clinical outcomes were assessed by questionnaires preoperatively and up to 2 yr postoperatively including neck and arm pain, Neck Disability Index, Euroqol 5-dimensions, and Short Form-36; x-rays from the same period were analyzed for range of movement and presence of heterotopic ossification.

RESULTS: A total of 44 NuNec™ discs were implanted in 33 patients. Clinical improvements were seen in all outcomes; significant improvements on the Neck Disability Index, Euroqol 5-dimensions, and physical domain of the Short Form-36 were maintained at 2 yr. There was a mean of 4◦ range of movement at the replacement disc level at 2 yr, a significant reduction from baseline; there was also progression in levels of heterotopic ossification. Complications included temporary dysphagia (10%) and progression of disease requiring foraminotomy (6%); no surgery for adjacent level disease was required. There was no significant difference in the outcomes of the radiculopathy and myelopathy groups.

CONCLUSION: Clinical outcomes using the NuNec™ disc replacement are comparable with other disc replacements. Although the range of movement is reduced, the reoperation rate is very low.

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GAVCA Study: Randomized, Multicenter Trial to Evaluate the Quality of Ventricular Catheter Placement with a Mobile Health Assisted Guidance Technique

Neurosurgery 83:252–262, 2018

Freehand ventricular catheter placementmay represent limited accuracy for the surgeon’s intent to achieve primary optimal catheter position.

OBJECTIVE: To investigate the accuracy of a ventricular catheter guide assisted by a simple mobile health application (mhealth app) in a multicenter, randomized, controlled, simple blinded study (GAVCA study).

METHODS: In total, 139 eligible patients were enrolled in 9 centers. Catheter placement was evaluated by 3 different components: number of ventricular cannulation attempts, a grading scale, and the anatomical position of the catheter tip. The primary endpoint was the rate of primary cannulation of grade I catheter position in the ipsilateral ventricle. The secondary endpoints were rate of intraventricular position of the catheter’s perforations, early ventricular catheter failure, and complications.

RESULTS: The primary endpoint was reached in 70% of the guided group vs 56.5% (freehand group; odds ratio 1.79, 95% confidence interval 0.89-3.61). The primary successful puncture rate was 100% vs 91.3% (P= .012). Catheter perforations were located completely inside the ventricle in 81.4% (guided group) and 65.2% (freehand group; odds ratio 2.34, 95% confidence interval 1.07-5.1). No differences occurred in early ventricular catheter failure, complication rate, duration of surgery, or hospital stay.

CONCLUSION: The guided ventricular catheter application proved to be a safe and simple method. The primary endpoint revealed a nonsignificant improvement of optimal catheter placement among the groups. Long-term follow-up is necessary in order to evaluate differences in catheter survival among shunted patients.

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Contralateral anterior interhemispheric transcallosal- transrostral approach to the subcallosal region

J Neurosurg 129:508–514, 2018

The authors report a novel surgical route from a superior anatomical aspect—the contralateral anterior interhemispheric-transcallosal-transrostral approach—to a lesion located in the subcallosal region. The neurosurgical approach to the subcallosal region is challenging due to its deep location and close relationship with important vascular structures. Anterior and inferior routes to the subcallosal region have been described but risk damaging the branches of the anterior cerebral artery.

METHODS Three formalin-fixed and silicone-injected adult cadaveric heads were studied to demonstrate the relationships between the transventricular surgical approach and the subcallosal region. The surgical, clinical, and radiological history of a 39-year-old man with a subcallosal cavernous malformation was retrospectively used to document the neurological examination and radiographic parameters of such a case.

RESULTS The contralateral anterior interhemispheric-transcallosal-transrostral approach provides access to the subcallosal area that also includes the inferior portion of the pericallosal cistern, lamina terminalis cistern, the paraterminal and paraolfactory gyri, and the anterior surface of the optic chiasm. The approach avoids the neurocritical perforating branches of the anterior communicating artery.

CONCLUSIONS The contralateral anterior interhemispheric-transcallosal-transrostral approach may be an alternative route to subcallosal area lesions, with less risk to the branches of the anterior cerebral artery, particularly the anterior communicating artery perforators.

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Subarachnoid hemorrhage after surgical treatment of unruptured intracranial aneurysms

J Neurosurg 129:490–497, 2018

Only a few previous studies have investigated subarachnoid hemorrhage (SAH) after surgical treatment in patients with unruptured intracranial aneurysms (UIAs). Given the improvement in long-term outcomes of embolization, more extensive data are needed concerning the true rupture rates after microsurgery in order to provide reliable information for treatment decisions. The purpose of this study was to investigate the incidence of and risk factors for postoperative SAH in patients with surgically treated UIAs.

METHODS Data from 702 consecutive patients harboring 852 surgically treated UIAs were evaluated. Surgical treatments included neck clipping (complete or incomplete), coating/wrapping, trapping, proximal occlusion, and bypass surgery. Clippable UIAs were defined as UIAs treated by complete neck clipping. The annual incidence of postoperative SAH and risk factors for SAH were studied using Kaplan-Meier survival analysis and Cox proportional hazards regression models.

RESULTS The patients’ median age was 64 years (interquartile range [IQR] 56–71 years). Of 852 UIAs, 767 were clippable and 85 were not. The mean duration of follow-up was 731 days (SD 380 days). During 1708 aneurysm years, there were 4 episodes of SAH, giving an overall average annual incidence rate of 0.23% (95% CI 0.12%–0.59%) and an average annual incidence rate of 0.065% (95% CI 0.0017%–0.37%) for clippable UIAs (1 episode of SAH, 1552 aneurysmyears). Basilar artery location (adjusted hazard ratio [HR] 23, 95% CI 2.0–255, p = 0.0012) and unclippable UIA status (adjusted HR 15, 95% CI 1.1–215, p = 0.046) were significantly related to postoperative SAH. An excellent outcome (modified Rankin Scale score of 0 or 1) was achieved in 816 (95.7%) of 852 cases overall and in 748 (98%) of 767 clippable UIAs at 12 months.

CONCLUSIONS In this large case series, microsurgical treatment of UIAs was found to be safe and effective. Aneurysm location and unclippable morphologies were related to postoperative SAH in patients with surgically treated UIAs.

 

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Fast gray matter acquisition T1 inversion recovery MRI to delineate the mammillothalamic tract for preoperative direct targeting of the anterior nucleus of the thalamus for deep brain stimulation in epilepsy


Neurosurg Focus 45 (2):E6, 2018

When medically intractable epilepsy is multifocal or focal but poorly localized, neuromodulation can be useful therapy. One such technique is deep brain stimulation (DBS) targeting the anterior nucleus of the thalamus (ANT). Unfortunately, the ANT is difficult to visualize in standard MRI sequences and its indirect targeting is difficult because of thalamic variability and atrophy in patients with epilepsy.

The following study describes the novel use of the fast gray matter acquisition T1 inversion recovery (FGATIR) MRI sequence to delineate the mammillothalamic tract for direct targeting of the ANT through visualizing the termination of the mammillothalamic tract in the ANT. The day prior to surgery in a 19-year-old, right-handed woman with a 5-year history of epilepsy, MRI was performed on a 3-T Siemens Prisma scanner (Siemens AG, Healthcare Sector) using a 64-channel head and neck coil. As part of the imaging protocol, noncontrast magnetization-prepared rapid gradient echo (MP-RAGE) and diffusion tensor imaging (DTI) sequences were obtained for targeting purposes.

The ANT was directly targeted using the FGATIR sequence, and bilateral Medtronic 3389 leads were placed.

At the last follow-up (2 months), the patient reported an approximate 75% decrease in seizure frequency, as well as a decrease in seizure severity.

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Tumor-associated hemorrhage in patients with vestibular schwannoma

Acta Neurochirurgica (2018) 160:1563–1569

Intratumoral hemorrhage (ITH) associated with vestibular schwannomas (VS) is very rare. We retrospectively analyzed VS patients presenting with ITH in our department to further gain a better understanding of this uncommon clinical presentation.

Methods We treated seven patients who had VS presenting with ITH between January 2012 and June 2017. All the patients had preoperative computed tomography (CT), computed tomography angiography (CTA), and magnetic resonance imaging(MRI) done which aided in the radiological diagnosis as well as postoperative MRI to confirm the resection extent of the VS. Continuous electrophysiological monitoring of cranial nerves was carried out during surgery.

Results Of the seven patients, three were male and four were female. Their ages ranged from 42 to 71 years (average age, 57.4 years). Two patients reported a history of hypertension. Sudden onset or rapid worsening of clinical symptoms occurred in five patients at time of hemorrhage. The mean diameter of the lesions was 4.1 cm (range, 3.0–5.0 cm). No patient had a pretreatment of stereotactic radiosurgery. Gross total resection was achieved in four cases and subtotal resection in three cases. There were no surgery-related neurological deficits but one patient died 18 days after surgery. Follow-up visits were scheduled at 6 months postoperatively and two patients had tumor recurrence and received stereotactic radiosurgery again.

Conclusions The incidence of ITH in VS is relatively rare and hypertension may highly correlate with ITH in VS. In comparison with peritumoral adhesion caused by chronic inflammation in multicystic VS with microhemorrhage,ITH caused by acute massive hemorrhage will not increase the extent of peritumoral adhesion immediately. The prognosis of surgery for patients with acute hemorrhagic VS may be better than that for microhemorrhage in multicystic VS. Besides, timely microsurgical treatment is also important to relieve symptoms.

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Full-endoscopic uniportal decompression in disc herniations and stenosis of the thoracic spine using the interlaminar, extraforaminal, or transthoracic retropleural approach

J Neurosurg Spine 29:157–168, 2018

Surgery for thoracic disc herniation and spinal canal stenosis is comparatively rare and often challenging. Individual planning and various surgical techniques and approaches are required. The key factors for selecting the technique and approach are anatomical location, consistency of the pathology, general condition of the patient, and the surgeon’s experience. The objective of the study was to evaluate the technical implementation and outcomes of a full endoscopic uniportal technique via the interlaminar, extraforaminal, or transthoracic retropleural approach in patients with symptomatic disc herniation and stenosis of the thoracic spine, taking specific advantages and disadvantages and literature into consideration.

METHODS Between 2009 and 2015, decompression was performed in 55 patients with thoracic disc herniation or stenosis using a full-endoscopic uniportal technique via an interlaminar, extraforaminal, or transthoracic retropleural approach. Imaging and clinical data were collected during follow-up examinations for 18 months.

RESULTS Sufficient decompression was achieved in the full-endoscopic uniportal technique. One patient required revision due to secondary bleeding, and another exhibited persistent deterioration on myelopathy. No other serious complications were observed. All but one patient experienced regression or improvement of their symptoms.

CONCLUSIONS The full-endoscopic uniportal technique with an interlaminar, extraforaminal, or transthoracic retropleural approach was found to be a sufficient and minimally invasive method. To cover the entire range of thoracic disc herniations and stenosis within the criteria named, all full-endoscopic approaches are required

 

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Simple Preoperative Patient-Reported Factors Predict Adverse Outcome After Elective Cranial Neurosurgery

Neurosurgery, 83, 2: 197–202

Patient-reported preoperative factors hold promise in improving the prediction of postoperative adverse events, but they have been poorly studied.
OBJECTIVE
To study the role of patient-reported factors in the preoperative risk stratification of elective craniotomy patients.
METHODS
A prospective, unselected cohort of 322 adult patients underwent elective craniotomy in Helsinki, Finland. We preoperatively recorded the American Society of Anesthesiologists (ASA) score, Helsinki ASA score, and 3 questionnaire-based patient-reported factors including overall health status, ability to climb 2 flights of stairs, and cognitive function (Test Your Memory test). Outcome measures comprised in-hospital major and overall morbidity. Receiver-operating characteristic curves served to calculate area under the curve (AUC) values for a composite score of patient-reported factors and both ASA scores with regard to outcomes.
RESULTS
In-hospital major and overall morbidity rate was 15.2%. Only preoperatively diminished cognitive function remained a significant predictor of major morbidity after multivariable logistic regression analysis (P < .001, odds ratio 1.1, confidence interval 1.0-1.1). A composite score of our 3 patient-reported factors had a higher AUC (0.675) for major morbidity than original ASA score (0.543) or Helsinki ASA score (0.572). In elderly patients, the composite score had an AUC of 0.726 for major morbidity.
CONCLUSION
Preoperative patient-reported factors had higher sensitivity for detecting major morbidity compared to the ASA scores in this study. Particularly, the simple composite score seems to predict adverse outcomes in elective cranial surgery surprisingly well, especially in the elderly. These results are interesting and worth confirming in other centers.

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Deep brain stimulation for dementias

Neurosurg Focus 45 (2):E8, 2018

The aim of this article is to review the authors’ and published experience with deep brain stimulation (DBS) therapy for the treatment of patients with Alzheimer’s disease (AD) and Parkinson’s disease dementia (PDD).

METHODS Two targets are current topics of investigation in the treatment of AD and PDD, the fornix and the nucleus basalis of Meynert. The authors reviewed the current published clinical experience with attention to patient selection, biological rationale of therapy, anatomical targeting, and clinical results and adverse events.

RESULTS A total of 7 clinical studies treating 57 AD patients and 7 PDD patients have been reported. Serious adverse events were reported in 6 (9%) patients; none resulted in death or disability. Most studies were case reports or Phase 1/2 investigations and were not designed to assess treatment efficacy. Isolated patient experiences demonstrating improved clinical response after DBS have been reported, but no significant or consistent cognitive benefits associated with DBS treatment could be identified across larger patient populations.

CONCLUSIONS PDD and AD are complex clinical entities, with investigation of DBS intervention still in an early phase. Recently published studies demonstrate acceptable surgical safety. For future studies to have adequate power to detect meaningful clinical changes, further refinement is needed in patient selection, metrics of clinical response, and optimal stimulation parameters.

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Techniques for Stereotactic Neurosurgery: Beyond the Frame, Toward the Intraoperative Magnetic Resonance Imaging Guided and Robot-Assisted Approaches

World Neurosurg. (2018) 116:77-87

The development of stereotaxy can be dated back 100 years. However, most stereotactic neurosurgery still relies on the workflow established about half a century ago. With the arrival of computer-assisted navigation, numerous studies to improve the neurosurgical technique have been reported, leading to frameless and magnetic resonance imaging (MRI)-guided/verified techniques. Frameless stereotaxy has been proved to be comparable to frame-based stereotaxy in accuracy, diagnostic yield, morbidity, and mortality.

The incorporation of intraoperative MRI guidance in frameless techniques is considered an appealing method that could simplify workflow by reducing coregistration errors in different imaging modalities, conducting general anesthesia, and monitoring the surgical progress. In light of this situation, manually operated platforms have emerged for MRI-guided frameless procedures.

However, these procedures could still be complicated and time-consuming because of the intensive manual operation required. To further simplify the procedure and enhance accuracy, robotics was introduced.

Robots have superior capabilities over humans in certain tasks, especially those that are limited by space, accuracy demanding, intensive, and tedious. Clinical benefits have been shown in the recent surge of robot-assisted surgical interventions. We review the state-of-the-art intraoperative MRI-guided robotic platforms for stereotactic neurosurgery.

To improve the surgical workflow and achieve greater clinical penetration, 3 key enabling techniques are proposed with emphasis on their current status, limitations, and future trends.

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Circulating serum oncologic miRNA in pediatric juvenile pilocytic astrocytoma patients predicts mural nodule volume

Acta Neurochirurgica (2018) 160:1571–1581

Juvenile pilocytic astrocytomas represent the largest group of pediatric brain tumors. The ideal management for these tumors is early, total surgical resection. To detect and track treatment response, a screening tool is needed to identify patients for surgical evaluation and assess the quality of treatment. The identification of aberrant miRNA profiles in the sera of juvenile pilocytic astrocytoma patients could provide such a screening tool.

Methods The authors reviewed the serum profiles of 84 oncologically relevant miRNAs in pediatric juvenile pilocytic astrocytoma patients via qPCR screening.

Results miR-21, miR-15b, miR-23a, and miR-146b were significantly elevated in the sera of JPA patients as compared to nononcologic controls, oncologic controls, and post-JPA resection samples (p < 0.001, 0.022, 0.034, 0.044). miR-21 had the highest AUC on ROC analysis (AUC > 0.99, sensitivity 75%, specificity 100%). All four miRNAs also correlated well with tumor mural nodule size, though they only poorly correlated with total tumor size, including cystic components (Spearman’s R2: miR-21 91.7 vs 6.9%, miR-15b 86.3 vs 23.1%, miR-23a 85.8 vs 23.0%, miR-146b 59.8 vs 11.9%).

Conclusion In this small pilot study, pediatric juvenile pilocytic astrocytoma patients had significant elevations in serum miR-21, miR-15b, miR-23a, and miR-146b levels that do not appear to be driven by hydrocephalus or local distortion of the intracranial contents. These alterations correlate with solid tumor component volume and reverse with complete tumor resection, suggesting that this serum miRNA profile may delineate biomarkers for screening and tracking juvenile pilocytic astrocytoma patients. Additional studies, with a larger cohort, are needed to verify these results.

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Development of a statistical model for discrimination of rupture status in posterior communicating artery aneurysms

Acta Neurochirurgica (2018) 160:1643–1652

Intracranial aneurysms at the posterior communicating artery (PCOM) are known to have high rupture rates compared to other locations. We developed and internally validated a statistical model discriminating between ruptured and unruptured PCOM aneurysms based on hemodynamic and geometric parameters, angio-architectures, and patient age with the objective of its future use for aneurysm risk assessment.

Methods A total of 289 PCOM aneurysms in 272 patients modeled with image-based computational fluid dynamics (CFD) were used to construct statistical models using logistic group lasso regression. These models were evaluated with respect to discrimination power and goodness of fit using tenfold nested cross-validation and a split-sample approach to mimic external validation.

Results The final model retained maximum and minimum wall shear stress (WSS), mean parent artery WSS, maximum and minimum oscillatory shear index, shear concentration index, and aneurysm peak flow velocity, along with aneurysm height and width, bulge location, non-sphericity index, mean Gaussian curvature, angio-architecture type, and patient age. The corresponding area under the curve (AUC) was 0.8359. When omitting data from each of the three largest contributing hospitals in turn, and applying the corresponding model on the left-out data, the AUCs were 0.7507, 0.7081, and 0.5842, respectively.

Conclusions Statistical models based on a combination of patient age, angio-architecture, hemodynamics, and geometric characteristics can discriminate between ruptured and unruptured PCOM aneurysms with an AUC of 84%. It is important to include data from different hospitals to create models of aneurysm rupture that are valid across hospital populations.

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Surgical intervention for pituitary apoplexy

J Neurosurg 129:417–424, 2018

Pituitary apoplexy is a clinical syndrome consisting of neurological and endocrine abnormalities secondary to hemorrhage or ischemia of an underlying pituitary adenoma. The authors investigated whether there was a significant difference in neurological, endocrine, and nonneuroendocrine outcomes for patients with pituitary apoplexy, based on the time between symptom onset and surgical intervention.

METHODS The authors retrospectively analyzed the medical records of 32 patients who had presented to their institutionith acute pituitary apoplexy and subsequently undergone endonasal transsphenoidal resection in the period from 2003 to 2014. All patients had undergone preoperative MRI demonstrating evidence of apoplexy in the form of intratumoral hemorrhage, ischemia, and necrosis. Neurological deficits, partial or complete endocrinopathy, and nonneuroendocrine abnormalities were analyzed both pre- and postoperatively.

RESULTS Preoperatively, neurological deficits including visual loss and cranial nerve palsies were found in 31 (97%) of the 32 patients, endocrinopathy in the form of partial or panhypopituitarism was seen in 28 patients (88%), and nonneuroendocrine signs and symptoms were seen in 32 patients (100%). Thirteen patients (41%) underwent surgery within 72 hours of symptom onset (“early”), whereas 19 patients (59%) underwent surgery more than 72 hours from symptom onset (“delayed”). Early versus delayed resection did not appear to significantly improve visual deficits, total visual loss, resolution of oculomotor palsy, recovery from hypopituitarism, or nonneuroendocrine signs and symptoms such as headache and encephalopathy. Overall, visual improvement was seen in 77% of patients, complete restoration of normal vision in 38% of patients, and resolution of preoperative oculomotor palsies in 81% of patients. Only 6 (21%) of 28 patients showed evidence of partial hormone recovery following preoperative hypopituitarism. An absence of benefit for early surgery held true even when considering time to surgery from symptom onset as a continuous variable.
CONCLUSIONS Neurological deficits such as visual loss and cranial neuropathies show moderate improvement following surgical decompression, as does preoperative hypopituitarism. The timing of surgical intervention relative to the onset of symptoms does not appear to significantly affect the resolution of neurological or endocrinological deficits.

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State of Robotic Mastoidectomy: Literature Review

Over the past 30 years, the application of robotics in the field of neurotology has grown. Robots are able to perform increasingly complex tasks with ever improving accuracy, allowing them to be used in a broad array of applications. A mastoidectomy, in which a drill is used to remove a portion of the mastoid part of the temporal bone at the base of the skull, is one such application. To determine the current state of neurotologic robotics in the specific context of mastoidectomy, a review of the literature was carried out. This qualitative review explores what has been done in this field to date, as well as what has yet to be done. Although the research suggests that robotics can be and has been successfully used to assist with mastoidectomy, it also suggests the incompleteness of robotic development in the field.

At present, only 2 robotic systems have been approved by the U.S. Food and Drug Administration for neurosurgical use and the literature lacks evidence of meaningful clinical testing of new systems to change that. The cost of robotics also remains prohibitive. However, strides have been made, with at least 1 robot for mastoidectomy having reached the point of cadaveric trials. In addition, the research suggests some of the characteristics that should be considered when designing robots for mastoidectomy, such as burr size and the type of forces that should be applied.

Overall, the outlook for robots in neurotology, particularly mastoidectomy, is bright but some hurdles still remain to be overcome.

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Autologous Cranioplasty is Associated with Increased Reoperation Rate: A Systematic Review and Meta-Analysis

Consensus regarding selection of synthetic versus autologous flap reimplantation for cranioplasty after decompressive craniectomy has not been reached and the multiple factors considered for each patient make comparative analysis challenging. This study examines the association between choice of material and related complications.

METHODS: A systematic literature review and meta-analysis were performed using PubMed for articles reporting delayed cranioplasty after decompressive craniectomy using a cohort design comparing autologous bone and synthetic implants. Extracted data included implant material and incidence of infection, reoperations related to implant, wound complications, and resorption. –

RESULTS: One randomized controlled trial and 11 cohort studies were included for a total of 1586 implants (950 bone, 636 synthetic). Autologous implants had significantly more reoperations than did synthetic implants (n [1586 implants; odds ratio [OR], 1.91; 95% confidence interval [CI], 1.40e2.61). Reoperations were most often because of resorption (54%, n [ 159/295) followed by infection (41%, n [ 121/295). The pooled incidence of resorption in autologous implants was 20% (n [ 159/791). Among the other outcomes, there was no significant difference for infections (n [ 1586; OR, 1.24; CI, 0.82e1.88) or wound complications (n [ 678; OR, 0.56; CI, 0.22e1.45). For the trauma subpopulation, there was no significant difference in infection rate with either material (n [ 197; OR, 1.89; CI; 0.59e6.09).

CONCLUSIONS: Autologous implants had significantly more reoperations primarily because of the intrinsic risk of resorption (level of evidence 3b).

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Outcomes of stereotactic radiosurgery for foramen magnum meningiomas: an international multicenter study

J Neurosurg 129:383–389, 2018

Meningiomas are the most common benign extramedullary lesions of the foramen magnum; however, their optimal management remains undefined. Given their location, foramen magnum meningiomas (FMMs) can cause significant morbidity, and complete microsurgical removal can be challenging. Anterior and anterolateral FMMs carry greater risks with surgery, but they comprise the majority of these lesions. As an alternative to resection, stereotactic radiosurgery (SRS) has been used to treat FMMs in small case series. To more clearly define the outcomes of SRS and to delineate a rational management paradigm for these lesions, the authors analyzed the safety and efficacy of SRS for FMM in an international multicenter trial.

METHODS Seven medical centers participating in the International Gamma Knife Research Foundation (IGKRF) provided data for this retrospective cohort study. Patients who were treated with Gamma Knife radiosurgery and whose clinical and radiological follow-up was longer than 6 months were eligible for study inclusion. Data from pre- and post- SRS radiological and clinical evaluations were analyzed. Stereotactic radiosurgery treatment variables were recorded.

RESULTS Fifty-seven patients (39 females and 18 males, with a median age of 64 years) met the study inclusion criteria. Thirty-two percent had undergone prior microsurgical resection. Patients most frequently presented with cranial neuropathy (39%), headache (35%), numbness (32%), and ataxia (30%). Median pre-SRS tumor volume was 2.9 cm3. Median SRS margin dose was 12.5 Gy (range 10–16 Gy). At the last follow-up after SRS, 49% of tumors were stable, 44% had regressed, and 7% had progressed. Progression-free survival rates at 5 and 10 years were each 92%. A greater margin dose was associated with a significantly increased likelihood of tumor regression, with 53% of tumors treated with > 12 Gy regressing. Fifty-two percent of symptomatic patients noted some clinical improvement. Adverse radiation effects were limited to hearing loss and numbness in 1 patient (2%).

CONCLUSIONS Stereotactic radiosurgery for FMM frequently results in tumor control or tumor regression, as well as symptom improvement. Margin doses > 12 Gy were associated with increased rates of tumor regression. Stereotactic radiosurgery was generally safe and well tolerated. Given its risk-benefit profile, SRS may be particularly useful in the management of small- to moderate-volume anterior and anterolateral FMMs.

 

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Indocyanine Green Videoangiography in Aneurysm Surgery: Systematic Review and Meta-Analysis

Neurosurgery, 83 (2): 166–180

Although digital subtraction angiography (DSA) may be considered the gold standard for intraoperative vascular imaging, many neurosurgical centers rely only on indocyanine green videoangiography (ICG-VA) for the evaluation of clipping accuracy. Many studies have compared the results of ICG-VA with those of intraoperative DSA; however, a systematic review summarizing these results is still lacking.
OBJECTIVE
To analyze the literature in order to evaluate ICG-VA accuracy in the identification of aneurysm remnants and vessel stenosis after aneurysm clipping.
METHODS
We performed a systematic literature review of ICG-VA accuracy during aneurysm clipping as compared to microscopic visual observation (primary endpoint 1) and DSA (primary endpoint 2). Quality of studies was assessed with the QUADAS-2 tool. Meta-analysis was performed using a random effects model.
RESULTS
The initial PubMed search resulted in 2871 records from January 2003 to April 2016; of these, 20 articles were eligible for primary endpoint 1 and 11 for primary endpoint 2. The rate of mis-clippings that eluded microscopic visual observation and were identified at ICG-VA was 6.1% (95% CI: 4.2-8.2), and the rate of mis-clippings that eluded ICG-VA and were identified at DSA was 4.5% (95% CI: 1.8-8.3).

CONCLUSION
Because a proportion of mis-clippings cannot be identified with ICG-VA, this technique should still be considered complementary rather than a replacement to DSA during aneurysm surgery. Incorporating other intraoperative tools, such as flowmetry or electrophysiological monitoring, can obviate the need for intraoperative DSA for the identification of vessel stenosis. Nevertheless, DSA likely remains the best tool for the detection of aneurysm remnants.

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Microsurgical Clipping of Ruptured Anterosuperior-Projecting Anterior Communicating Artery Aneurysms: How We Do It

World Neurosurg. (2018) 116:133-135

In anterosuperior-projecting anterior communicating artery (ACoA) aneurysms, the aneurysm dome usually adheres to 1 or both proximal A2 segments, which may present technical difficulties. This video demonstrates microsurgical clipping of a ruptured anterosuperior-projecting ACoA aneurysm. A 52-year-old male presented with a Hunt-Hess grade II subarachnoid hemorrhage. Computed tomography showed subarachnoid hemorrhage in the basal cisterns and sylvian and interhemispheric fissures. Angiography demonstrated a wide-necked ACoA aneurysm projecting anterosuperiorly. Considering the risk of recurrence, the patient decided to accept surgical treatment.

The patient was positioned supine, and the aneurysm was exposed via the lateral supraorbital approach. The carotid cistern and optic cistern were opened to release cerebrospinal fluid and achieve adequate brain relaxation. A subpial resection of a small portion of the gyrus rectus was performed to visualize the ipsilateral A2, recurrent artery of Heubner, and base of the aneurysm. A plane was dissected between the anterior aspect of both the A2 segment and posterior aspect of the aneurysm. A straight clip was placed parallel to the ACoA to completely obliterate the aneurysm. Postoperative angiography confirmed complete obliteration of the aneurysm. The patient recovered well without any complications.

Successful treatment requires preoperative surgical planning, precise dissection, and preservation of critical structures. With adherence to these general principles, these aneurysms can be treated safely and effectively.

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Volumetric tumor growth rates of meningiomas involving the intracranial venous sinuses

Acta Neurochirurgica (2018) 160:1531–1538

There is currently no consensus as to whether meningiomas located inside the venous sinuses should be aggressively or conservatively treated. The goals of this study were to identify how sinus-invading meningiomas grow, report and compare growth rates of tumor components inside and outside the different venous sinuses, identify risk factors associated with increased tumor growth, and determine the effects of the extent of tumor resection on recurrence for meningiomas that invade the dural venous sinuses.

Methods Adult patients who underwent primary, non-biopsy resection of a WHO grade 1 meningioma invading the dural venous sinuses at a tertiary care institution between 2007 and 2015 were retrospectively reviewed. Rates of tumor growth were fit to several growth models to evaluate the most accurate model. Cohen’s d analysis was used to identify associations with increased growth of tumor in the venous sinuses. Logistic regression was used to compare extent of resection with recurrence.

Results Of the 68 patients included in the study, 34 patients had postoperative residual tumors in the venous sinuses that were measured over time. The growth model that best fit the growth of intrasinus meningiomas was the Gompertzian growth model (r2 = 0.93). The annual growth rate of meningiomas inside the sinuses was 7.3%, compared to extrasinus tumors with 13.6% growth per year. The only factor significantly associated with increased tumor growth in sinuses was preoperative embolization (effect sizes (ES) [95% CI], 1.874 [7.633–46.735], p = 0.008).

Conclusions This study shows that meningiomas involving the venous sinuses have a Gompertzian-type growth with early exponential growth followed by a slower growth rate that plateaus when they reach a certain size. Overall, the growth rate of the intrasinus portion is low (7.3%), which is half of the reported growth rates for other studies involving primarily extrasinus tumors.

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