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Microsurgery for Spetzler-Ponce Class A and B arteriovenous malformations utilizing an outcome score adopted from Gamma Knife radiosurgery

J Neurosurg 127:1105–1116, 2017

The purpose of this study was to adapt and apply the extended definition of favorable outcome established for Gamma Knife radiosurgery (GKRS) to surgery for brain arteriovenous malformations (bAVMs). The aim was to derive both an error around the point estimate and a model incorporating angioarchitectural features in order to facilitate comparison among different treatments.

METHODS A prospective microsurgical cohort was analyzed. This cohort included patients undergoing embolization who did not proceed to microsurgery and patients denied surgery because of perceived risk of treatment. Data on bAVM residual and recurrence during long-term follow-up as well as complications of surgery and preoperative embolization were analyzed. Patients with Spetzler-Ponce Class C bAVMs were excluded because of extreme selection bias. First, patients with a favorable outcome were identified for both Class A and Class B lesions. Patients were considered to have a favorable outcome if they were free of bAVM recurrence or residual at last follow-up, with no complication of surgery or preoperative embolization, and a modified Rankin Scale score of more than 1 at 12 months after treatment. Patients who were denied surgery because of perceived risk, but would otherwise have been candidates for surgery, were included as not having a favorable outcome. Second, the authors analyzed favorable outcome from microsurgery by means of regression analysis, using as predictors characteristics previously identified to be associated with complications. Third, they created a prediction model of favorable outcome for microsurgery dependent upon angioarchitectural variables derived from the regression analysis.

RESULTS From a cohort of 675 patients who were either treated or denied surgery because of perceived risk of surgery, 562 had Spetzler-Ponce Class A or B bAVMs and were included in the analysis. Logistic regression for favorable outcome found decreasing maximum diameter (continuous, OR 0.62, 95% CI 0.51–0.76), the absence of eloquent location (OR 0.23, 95% CI 0.12–0.43), and the absence of deep venous drainage (OR 0.19, 95% CI 0.10–0.36) to be significant predictors of favorable outcome. These variables are in agreement with previous analyses of microsurgery leading to complications, and the findings support the use of favorable outcome for microsurgery. The model developed for angioarchitectural features predicts a range of favorable outcome at 8 years following microsurgery for Class A bAVMs to be 88%–99%. The same model for Class B bAVMs predicts a range of favorable outcome of 62%–90%.

CONCLUSIONS Favorable outcome, derived from GKRS, can be successfully used for microsurgical cohort series to assist in treatment recommendations. A favorable outcome can be achieved by microsurgery in at least 90% of cases at 8 years following microsurgery for patients with bAVMs smaller than 2.5 cm in maximum diameter and, in the absence of either deep venous drainage or eloquent location, patients with Spetzler-Ponce Class A bAVMs of all diameters. For patients with Class B bAVMs, this rate of favorable outcome can only be approached for lesions with a maximum diameter just above 6 cm or smaller and without deep venous drainage or eloquent location.

 

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Patterns of C-2 fracture in the elderly: comparison of etiology, treatment, and mortality among speci c fracture types

J Neurosurg Spine 27:494–500, 2017

Previous studies have focused on Type II odontoid fractures and have failed to report on the effect of other C-2 fracture types on treatment and outcome. The purpose of this study was to compare patient characteristics, cause of injury, predisposing factors to fracture, treatments, and mortality rates among C-2 fracture types in a cohort of elderly patients 70 years of age and older.

METHODS A retrospective cohort study design was used. Patients who sustained a C-2 fracture between 2002 and 2011 and who were admitted to the authors’ Level 1 trauma center were identified using the Discharge Abstract Database and the International Statistical Classification of Diseases and Related Health Problems (ICD-10) code S12.1. Fractures were classified as odontoid Type I, II, or III; hangman’s; C-2 complex (hangman’s appearance on sagittal images, Type III odontoid on coronal cuts); and other (miscellaneous). Age, sex, predisposing factors to falls, cause of injury, treatment, presence of autofusion in the subaxial cervical spine, and mortality rates were compared between fracture patterns.

RESULTS One hundred forty-one patients were included; their mean age was 82 years. Fractures included Type II odontoid (57%), complex (19%), Type III odontoid (11%), hangman’s (8%), and other (5%). Falls from a standing height accounted for 47% of injuries, and 65% of patients had ≥ 3 risk factors for falls. Subaxial autofusion was more common in odontoid fractures (p = 0.002). Treatment was mainly nonoperative (p < 0.0001). The 1-year mortality rate was 27%. Four patients died of spinal cord injury.

CONCLUSIONS Although not as common as Type II odontoid fractures, other C-2 fractures including hangman’s, complex, and Type III odontoid fractures accounted for close to half of the injuries in the study cohort. There were few differences between the fracture types with respect to cause of injury, predisposing factors, or mortality rate. However, surgical treatment was more common for Type II odontoid fractures.

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Timing of surgery for ruptured supratentorial arteriovenous malformations

Acta Neurochir (2017) 159:2103–2112

There are conflicting opinions regarding the optimal waiting time to perform surgery after rupture of supratentorial arteriovenous malformations (AVMs) to achieve the best possible outcome.

Objective To analyze factors influencing outcomes for ruptured supratentorial AVMs after surgery, paying particular attention to the timing of the surgery.

Methods We retrospectively investigated 59 patients admitted to our center between 2000 and 2014 for surgical treatment of ruptured supratentorial AVMs. We evaluated the effect of timing of surgery and other variables on the outcome at 2– 4 months (early outcome), at 12 months (intermediate outcome) after surgery, and at final follow-up at the end of 2016 (late outcome).

Results Age over 40 years (OR 18.4; 95% CI 1.9–172.1; p = 0.011), high Hunt and Hess grade (4 or 5) before surgery (OR 13.5; 95% CI 2.1–89.2; p = 0.007), hydrocephalus on admission (OR 12.9; 95% CI 1.8–94.4; p = 0.011), and over 400 cm3 bleeding during surgery (OR 11.5; 95% CI 1.5–86.6; p = 0.017) were associated with an unfavorable early outcome. Age over 40 years (OR 62.8; 95% CI 2.6–1524.9; p = 0.011), associated aneurysms (OR 34.7; 95% CI 1.4– 829.9; p = 0.029), high Hunt and Hess grade before surgery (OR 29.2; 95% CI 2.6–332.6; p = 0.007), and over 400 cm3 bleeding during surgery (OR 35.3; 95% CI 1.7–748.7; p = 0.022) were associated with an unfavorable intermediate outcome. Associated aneurysms (OR 8.2; 95% CI 1.2–55.7; p = 0.031), high Hunt and Hess grade before surgery (OR 5.7; 95% CI 1.3–24.3; p = 0.019), and over 400 cm3 bleeding during surgery (OR 5.8; 95% CI 1.2–27.3; p = 0.027) were associated with an unfavorable outcome at last follow-up. Elapsed time between rupture and surgery did not affect early or final outcome. Conclusions Early surgery in patients with ruptured supratentorial arteriovenous malformation is

Conclusions Early surgery in patients with ruptured supratentorial arteriovenous malformation is feasible strategy, with late results comparable to those achieved with delayed surgery. Many other factors than timing of surgery play significant roles in long-term outcomes for surgically treated ruptured supratentorial AVMs.

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Predictive factors for recurrence and clinical outcomes in patients with chronic subdural hematoma

J Neurosurg 127:1117–1125, 2017

Chronic subdural hematoma (CSDH) is a common type of intracranial hemorrhage in elderly patients. Many studies have suggested various factors that may be associated with the recurrence of CSDH. However, the results are inconsistent. The purpose of this study was to determine the associations among patient factors, recurrence, and clinical outcomes of CSDH after burr hole surgery performed during an 11-year period at twin hospitals.

METHODS Kaplan-Meier analysis was performed to evaluate the risk factors for CSDH recurrence. Univariate and multivariate Cox proportional hazards regression analyses were used to calculate hazard ratios with 95% CIs for CSDH recurrence based on many variables. One-way repeated-measures ANOVA was used to assess the differences in the mean modified Rankin Scale score between categories for each risk factor during each admission and at the last follow-up.

RESULTS This study was a retrospective analysis of 756 consecutive patients with CSDH who underwent burr hole surgery at the Hanyang University Medical Center (Seoul and Guri) between January 1, 2004, and December 31, 2014. During the 6-month follow-up, 104 patients (13.8%) with recurrence after surgery for CSDH were identified. Independent risk factors for recurrence were as follows: age > 75 years (HR 1.72, 95% CI 1.03–2.88; p = 0.039), obesity (body mass index ≥ 25.0 kg/m2), and a bilateral operation.

CONCLUSIONS This study determined the risk factors for recurrence of CSDH and their effects on outcomes. Further studies are needed to account for these observations and to determine their underlying mechanisms.

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Clinical relevance of anterior cerebral artery asymmetry in aneurysmal subarachnoid hemorrhage

J Neurosurg 127:1070–1076, 2017

An asymmetry of the A1 segments (A1SA) of the anterior cerebral arteries (ACAs) is an assumed risk factor for the development of anterior communicating artery aneurysms (ACoAAs). It is unknown whether A1SA is also clinically relevant after aneurysm rupture. The authors of this study investigated the impact of A1SA on the clinical course and outcome of patients with aneurysmal subarachnoid hemorrhage (SAH).

METHODS The authors retrospectively analyzed data on consecutive SAH patients treated at their institution between January 2005 and December 2012. The occurrence and severity of cerebral infarctions in the ACA territories were evaluated on follow-up CT scans up to 6 weeks after SAH. Moreover, the risk for an unfavorable outcome (defined as > 3 points on the modified Rankin Scale) at 6 months after SAH was assessed.

RESULTS A total of 594 patients were included in the final analysis. An A1SA was identified on digital subtraction angiography studies from 127 patients (21.4%) and was strongly associated with ACoAA (p < 0.0001, OR 13.7). An A1SA independently correlated with the occurrence of ACA infarction in patients with ACoAA (p = 0.047) and in those without an ACoAA (p = 0.015). Among patients undergoing ACoAA coiling, A1SA was independently associated with the severity of ACA infarction (p = 0.023) and unfavorable functional outcome (p = 0.045, OR = 2.4).

CONCLUSIONS An A1SA is a common anatomical variation in SAH patients and is strongly associated with ACoAA. Moreover, the presence of A1SA independently increases the likelihood of ACA infarction. In SAH patients undergoing ACoAA coiling, A1SA carries the risk for severe ACA infarction and thus an unfavorable outcome.

 

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Transforaminal Lumbar Interbody Fusion Versus Mini-open Anterior Lumbar Interbody Fusion With Oblique Self-anchored Stand-alone Cages for the Treatment of Lumbar Disc Herniation

Spine 2017;42:E1259–E1265

The aim of this study was to evaluate the clinical and radiological outcomes of mini-open ALIF (MO-ALIF) with self-anchored stand-alone cages for the treatment of lumbar disc herniation in comparison with transforaminal lumbar interbody fusion (TLIF). Summary of Background Data. Currently, whether ALIF is superior to TLIF for the treatment of lumbar disc herniation remains controversial.

Summary of Background Data. Currently, whether ALIF is superior to TLIF for the treatment of lumbar disc herniation remains controversial.

Methods. This study retrospectively reviewed 82 patients who underwent MO-ALIF with self-anchored standalone cages (n=42) or TLIF (n=40) for the treatment of lumbar disc herniation between April 2013 and October 2014. Patient demographics, intraoperative parameters, and perioperative complications were collated. Clinical outcomes were evaluated using the visual analog scale (VAS) scoring, the Oswestry Disability Index (ODI) for pain in the leg and back, and radiological outcomes, including fusion, lumbar lordosis (LL), disc height (DH), and cage subsidence were evaluated at each follow-up for up to 2 years.

Results. Patients who underwent TLIF had a significantly higher volume of blood loss (295.2±81.4 vs. 57.0±15.2mL) and longer surgery time (130.7±45.1 vs. 60.4±20.8 min) than those who had MO-ALIF. Compared with baseline, both groups had significant improvements in the VAS and ODI scores and DH and LL postoperatively, though no significant difference was found between the two groups regarding these indexes. All patients reached solid fusion at the final follow-up in both groups. Three patients (3/42) with three levels (3/50) suffered from cage subsidence in the MO-ALIF group; meanwhile, no cage subsidence occurred in the TLIF group. Conclusion. MO-ALIF with self-anchored stand-alone cages is a safe and effective treatment of lumbar disc herniation with less surgical trauma and similar clinical and radiological outcomes compared with TLIF.

Conclusion. MO-ALIF with self-anchored stand-alone cages is a safe and effective treatment of lumbar disc herniation with less surgical trauma and similar clinical and radiological outcomes compared with TLIF.

Level of Evidence: 3

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Long-term surgical results of supplementary motor area epilepsy surgery

J Neurosurg 127:1153–1159, 2017

Supplementary motor area (SMA) epilepsy is a well-known clinical condition; however, long-term surgical outcome reports are scarce and correspond to small series or isolated case reports. The aim of this study is to present the surgical results of SMA epilepsy patients treated at 2 reference centers in Mexico City.

METHODS For this retrospective descriptive study (1999–2014), 52 patients underwent lesionectomy and/or corticectomy of the SMA that was guided by electrocorticography (ECoG). The clinical, neurophysiological, neuroimaging, and pathological findings are described. The Engel scale was used to classify surgical outcome. Descriptive statistics, Student t-test, and Friedman, Kruskal-Wallis, and chi-square tests were used.

RESULTS Of these 52 patients, the mean age at epilepsy onset was 26.3 years, and the mean preoperative seizure frequency was 14 seizures per month. Etiologies included low-grade tumors in 28 (53.8%) patients, cortical dysplasia in 17 (32.7%) patients, and cavernomas in 7 (13.5%) patients. At a mean follow-up of 5.7 years (range 1–10 years), 32 patients (61%) were classified as Engel Class I, 16 patients (31%) were classified as Engel Class II, and 4 (8%) patients were classified as Engel Class III. Overall seizure reduction was significant (p = 0.001). The absence of early postsurgical seizures and lesional etiology were associated with the outcome of Engel Class I (p = 0.05). Twenty-six (50%) patients had complications in the immediate postoperative period, all of which resolved completely with no residual neurological deficits.

CONCLUSIONS Surgery for SMA epilepsy guided by ECoG using a multidisciplinary and multimodality approach is a safe, feasible procedure that shows good seizure control, moderate morbidity, and no mortality.

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Dexamethasone for chronic subdural haematoma: a systematic review and meta-analysis

Acta Neurochir (2017) 159:2037–2044

Chronic subdural haematoma is a common but retractable neurological disease in the elderly with a high rate of recurrence. Dexamethasone (DX) either as monotherapy or adjuvant therapy has been applied clinically, but its effectiveness and feasibility remain controversial. We conducted this review to clarify this issue. Methods With a systematic review through multiple databases, we retrieved eligible English language publications and extracted relevant data to perform meta-analyses. The respective risk ratio (RR) and its 95% confidence interval (CI) were pooled to evaluate the overall effect. Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference

Methods With a systematic review through multiple databases, we retrieved eligible English language publications and extracted relevant data to perform meta-analyses. The respective risk ratio (RR) and its 95% confidence interval (CI) were pooled to evaluate the overall effect. Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference

Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference on recurrence rate between DX alone and non-DX therapy or surgical therapy (RR, 0.86; 95% CI, 0.43-1.71; p = 0.66) (RR, 0.89; 95% CI, 0.43-1.85; p = 0.76). Comparison between DX alone with the surgical therapy demonstrated no difference on the poor outcome (RR, 0.40; 95% CI, 0.15-1.04; p = 0.06). Conclusions We had

Conclusions We had no enough evidence to support DX use as an effective alternation to surgical therapy. But adjuvant DX use may facilitate the surgical therapy by reducing recurrence. Further study focusing on adjuvant DX was required.

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Microvascular Decompression for Trigeminal Neuralgia Using a Novel Fenestrated Clip and Tentorial Flap Technique

WORLD NEUROSURGERY 106: 775-784, 2017

Microvascular decompression (MVD) for neurovascular compression syndromes, such as trigeminal neuralgia and hemifacial spasm, has been traditionally described as an interposing technique using Teflon. Some alternative interposing materials have been proposed. In addition, transposing techniques have been increasingly reported as an alternative with a potentially lower recurrence rate and fewer complications.

OBJECTIVE: To describe our experience with a technique consisting of transposition of the superior cerebellar artery using a fenestrated clip and a tentorial flap in patients with trigeminal neuralgia.

METHODS: We describe a novel transposing technique using a fenestrated clip and a tentorial flap in patients with neurovascular compression. An illustrative case is provided of an 83-year-old female patient who complained of a 4-year history of left trigeminal neuralgia caused by compression by the superior cerebellar artery who was treated with this technique. Furthermore, a thorough review of the literature is presented. –

RESULTS: The patient underwent the procedure with the proposed technique without complication. Both the surgery and the postoperative course were uneventful. The patient remains asymptomatic 1 year after the procedure.

CONCLUSION: We propose a novel technique for the treatment of trigeminal neuralgia, eliminating the need for padding the vessel with a foreign body. This technique can be applied successfully in selected cases of neurovascular compression syndromes.

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Complex Internal Carotid Artery Aneurysm Treated by Extracranial to Intracranial Bypass Using High-Flow Grafts with Therapeutic Internal Carotid Artery Occlusion

Neurosurgery 81:672–679, 2017

Although the extracranial-to-intracranial high-flow bypass (EC-IC HFB) continues to be indispensable for complex aneurysms, the risk factors for the graft occlusion and whether the graft size changes after the bypass have not been well established.

OBJECTIVE: To evaluate the risk factors for the graft occlusion and to confirm whether graft diameters changed over time.

METHODS: The data of 75 patients who suffered from complex internal carotid artery (ICA) aneurysms and were treated by EC-IC HFB using radial artery graft (RAG) or saphenous vein graft (SVG) with therapeutic ICA occlusion were evaluated. Clinical and radiological characteristics were compared in patients with and without the graft occlusion by the logrank test. Graft diameters measured preoperatively, postoperatively, at 6 months, and at 1 year were compared by paired t-test.

RESULTS: During a follow-up period (median 26.2 months), graft occlusions were seen in 4 patients (5.3%), and these were the SVGs. Only SVG was related to graft occlusion (P<.001). There was a significant increase with time in RAG diameters (preoperative, 3.1 ± 0.41 mm; postoperative, 3.6 ± 0.65 mm; 6 months, 4.3 ± 1.0 mm; 1 year, 4.4 ± 1.0 mm), while there were no significant diameter changes in SVGs.

CONCLUSION: The present study showed that the SVG was related to the graft occlusion and RAGs gradually enlarged. Unless Allen test is negative, RAG may be better to be used as a graft in EC-IC HFB if therapeutic ICA occlusion is needed.

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Histopathological Findings in Brain Tissue Obtained during Epilepsy Surgery

N Engl J Med 2017;377:1648-56

Detailed neuropathological information on the structural brain lesions underlying seizures is valuable for understanding drug-resistant focal epilepsy.

METHODS We report the diagnoses made on the basis of resected brain specimens from 9523 patients who underwent epilepsy surgery for drug-resistant seizures in 36 centers from 12 European countries over 25 years. Histopathological diagnoses were determined through examination of the specimens in local hospitals (41%) or at the German Neuropathology Reference Center for Epilepsy Surgery (59%).

RESULTS The onset of seizures occurred before 18 years of age in 75.9% of patients overall, and 72.5% of the patients underwent surgery as adults. The mean duration of epilepsy before surgical resection was 20.1 years among adults and 5.3 years among children. The temporal lobe was involved in 71.9% of operations. There were 36 histopathological diagnoses in seven major disease categories. The most common categories were hippocampal sclerosis, found in 36.4% of the patients (88.7% of cases were in adults), tumors (mainly ganglioglioma) in 23.6%, and malformations of cortical development in 19.8% (focal cortical dysplasia was the most common type, 52.7% of cases of which were in children). No histopathological diagnosis could be established for 7.7% of the patients.

CONCLUSIONS In patients with drug-resistant focal epilepsy requiring surgery, hippocampal sclerosis was the most common histopathological diagnosis among adults, and focal cortical dysplasia was the most common diagnosis among children. Tumors were the second most common lesion in both groups. (Funded by the European Union and others.)

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Asleep Robot-Assisted Surgery for the Implantation of Subthalamic Electrodes Provides the Same Clinical Improvement and Therapeutic Window as Awake Surgery

OBJECTIVE: To study the impact of not performing awake clinical evaluation during the robot-assisted implantation of subthalamic nucleus deep brain stimulation (STN-DBS) electrodes on the stimulation parameters and clinical outcomes in patients with Parkinson disease (PD).

METHODS: A total of 23 patients with PD underwent robot-assisted surgery for the bilateral implantation of STN-DBS electrodes. Thirteen patients received general anesthesia (GA) and a limited intraoperative evaluation (side effects only), and the other 10 patients received local anesthesia (LA) and a full evaluation. The primary endpoint was the therapeutic window (TW), defined as the difference between the mean voltage threshold for motor improvement and the mean voltage threshold for side effects in the active contacts at 12 months after surgery. Motor scores were measured as well.

RESULTS: The TW was similar in the LA and GA groups, with mean  standard deviation values of 2.06  0.53 V and 2.28  0.99 V, respectively (P [ 0.32). In the short term, the Unified Parkinson Disease Rating Scale (UPDRS) III score in the “off-drug, on-stim” condition fell to a similar extent in the LA and GA groups (by 40.3% and 49%, respectively; P [ 0.336), as did the UPDRS III score in the “on-stim, ondrug” condition (by 57% and 70.7%, respectively; P [ 0.36).

CONCLUSIONS: Asleep, robot-assisted implantation of STN-DBS electrodes (with accurate identification of the STN and positioning of the DBS lead) produced the same motor results and TW as awake surgery.

 

 

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Navigated transcranial magnetic stimulation for glioma removal- prognostic value in motor function recovery from postsurgical neurological deficits

J Neurosurg 127:877–891, 2017

The aim of the present study was to evaluate the usefulness of navigated transcranial magnetic stimulation (nTMS) as a prognostic predictor for upper-extremity motor functional recovery from postsurgical neurological deficits.

METHODS Preoperative and postoperative nTMS studies were prospectively applied in 14 patients (mean age 39 ± 12 years) who had intraparenchymal brain neoplasms located within or adjacent to the motor eloquent area in the cerebral hemisphere. Mapping by nTMS was done 3 times, i.e., before surgery, and 1 week and 3 weeks after surgery. To assess the response induced by nTMS, motor evoked potential (nTMS-MEP) was recorded using a surface electromyography electrode attached to the abductor pollicis brevis (APB). The cortical locations that elicited the largest electromyography response by nTMS were defined as hotspots. Hotspots for APB were confirmed as positive responsive sites by direct electrical stimulation (DES) during awake craniotomy. The distances between hotspots and lesions (DHS-L) were measured. Postoperative neurological deficits were assessed by manual muscle test and dynamometer. To validate the prognostic value of nTMS in recovery from upper-extremity paresis, the following were investigated: 1) the correlation between DHS-L and the serial grip strength change, and 2) the correlation between positive nTMS-MEP at 1 week after surgery and the serial grip strength change.

RESULTS From the presurgical nTMS study, MEPs from targeted muscles were identified in 13 cases from affected hemispheres. In one case, MEP was not evoked due to a huge tumor. Among 9 cases from which intraoperative DES mapping for hand motor area was available, hotspots for APB identified by nTMS were concordant with DES-positive sites. Compared with the adjacent group (DHS-L < 10 mm, n = 6), the nonadjacent group (DHS-L ≥ 10 mm, n = 7) showed significantly better recovery of grip strength at 3 months after surgery (p < 0.01). There were correlations between DHS-L and recovery of grip strength at 1 week, 3 weeks, and 3 months after surgery (r = 0.74, 0.68, and 0.65, respectively). Postsurgical nTMS was accomplished in 13 patients. In 9 of 13 cases, nTMS-MEP from APB muscle was positive at 1 week after surgery. Excluding the case in which nTMS-MEP was negative from the presurgical nTMS study, recoveries in grip strength were compared between 2 groups, in which nTMS-MEP at 1 week after surgery was positive (n = 9) or negative (n = 3). Significant differences were observed between the 2 groups at 1 week, 3 weeks, and 3 months after surgery (p < 0.01). Positive nTMS-MEP at 1 week after surgery correlated well with the motor recovery at 1 week, 3 weeks, and 3 months after surgery (r = 0.87, 0.88, and 0.77, respectively).

CONCLUSIONS Navigated TMS is a useful tool for identifying motor eloquent areas. The results of the present study have demonstrated the predictive value of nTMS in upper-extremity motor function recovery from postsurgical neurological deficits. The longer DHS-L and positive nTMS-MEP at 1 week after surgery have prognostic values of better recovery from postsurgical neurological deficits.

 

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Tonsillobiventral fissure approach to the lateral recess of the fourth ventricle

J Neurosurg (127): 768-774, 2017

Surgical access to the lateral recess of the fourth ventricle (LR) is suboptimal with existing transvermian and telovelar approaches because of limited lateral exposure, significant retraction of the cerebellar tonsil, and steep trajectories near brainstem perforator arteries. The goal in this study was to assess surgical exposure of the tonsillobiventral fissure approach to the LR, and to describe the relevant anatomy.

METHODS Two formaldehyde-fixed cerebella were used to study the anatomical relationships of the LR. Also, the tonsillobiventral fissure approach was simulated in 8 specimens through a lateral suboccipital craniotomy.

RESULTS The pattern of the cerebellar folia and the cortical branches of the posterior inferior cerebellar artery were key landmarks to identifying the tonsillobiventral fissure. Splitting the tonsillobiventral fissure allowed a direct and safe surgical trajectory to the LR and into the cerebellopontine cistern. The proposed approach reduces cervical flexion and optimizes the surgical angle of attack.

CONCLUSIONS The tonsillobiventral fissure approach is a feasible and effective option for exposing the LR. This approach has more favorable trajectories and positions for the patient and the surgeon, and it should be added to the armamentarium for lesions in this location.

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The Superior Frontal Transsulcal Approach to the Anterior Ventricular System

OBJECTIVE: To explore the superior frontal sulcus (SFS) morphology, trajectory of the applied surgical corridor, and white matter bundles that are traversed during the superior frontal transsulcal transventricular approach.

METHODS: Twenty normal, adult, formalin-fixed cerebral hemispheres and 2 cadaveric heads were included in the study. The topography, morphology, and dimensions of the SFS were recorded in all specimens. Fourteen hemispheres were investigated through the fiber dissection technique whereas the remaining 6 were explored using coronal cuts. The cadaveric heads were used to perform the superior frontal transsulcal transventricular approach. In addition, 2 healthy volunteers underwent diffusion tensor imaging and tractography reconstruction studies.

RESULTS: The SFS was interrupted in 40% of the specimens studied and was always parallel to the interhemispheric fissure. The proximal 5 cm of the SFS (starting from the SFS precentral sulcus meeting point) were found to overlie the anterior ventricular system in all hemispheres. Five discrete white matter layers were identified en route to the anterior ventricular system (i.e., the arcuate fibers, the frontal aslant tract, the external capsule, internal capsule, and the callosal radiations). Diffusion tensor imaging studies confirmed the fiber tract architecture.

CONCLUSIONS: When feasible, the superior frontal transsulcal transventricular approach offers a safe and effective corridor to the anterior part of the lateral ventricle because it minimizes brain retraction and transgression and offers a wide and straightforward working corridor. Meticulous preoperative planning coupled with a sound microneurosurgical technique are prerequisites to perform the approach successfully

 

 

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The anterior temporal artery: an underutilized but robust donor for revascularization of the distal middle cerebral artery

J Neurosurg 127:740–747, 2017

The anterior temporal artery (ATA) supplies an area of the brain that, if sacrificed, does not cause a noticeable loss of function. Therefore, the ATA may be used as a donor in intracranial-intracranial (IC-IC) bypass procedures. The capacities of the ATA as a donor have not been studied previously. In this study, the authors assessed the feasibility of using the ATA as a donor for revascularization of different segments of the distal middle cerebral artery (MCA).

METHODS The ATA was studied in 15 cadaveric specimens (8 heads, excluding 1 side). First, the cisternal segment of the artery was untethered from arachnoid adhesions and small branches feeding the anterior temporal lobe and insular cortex, to evaluate its capacity for a side-to-side bypass to insular, opercular, and cortical segments of the MCA. Any branch entering the anterior perforated substance was preserved. Then, the ATA was cut at the opercular-cortical junction and the capacity for an end-to-side bypass was assessed.

RESULTS From a total of 17 ATAs, 4 (23.5%) arose as an early MCA branch. The anterior insular zone and the frontal parasylvian cortical arteries were the best targets (in terms of mobility and caliber match) for a side-to-side bypass. Most of the insula was accessible for end-to-side bypass, but anterior zones of the insula were more accessible than posterior zones. End-to-side bypass was feasible for most recipient cortical arteries along the opercula, except for posterior temporal and parietal regions. Early ATAs reached significantly farther on the insular MCA recipients than non-early ATAs for both side-to-side and end-to-side bypasses.

CONCLUSIONS The ATA is a robust arterial donor for IC-IC bypass procedures, including side-to-side and end-to-side techniques. The evidence provided in this work supports the use of the ATA as a donor for distal MCA revascularization in well-selected patients.

 

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Predictors for Patient Discharge Destination After Elective Anterior Cervical Discectomy and Fusion

Spine 2017;42:1538–1544

Study Design. Retrospective study of prospectively collected data.

Objective. To identify risk factors for nonhome patient discharge after elective anterior cervical discectomy and fusion (ACDF).

Summary of Background Data. ACDF is one of the most performed spinal procedures and this is expected to increase in the coming years. To effectively deal with an increasing patient volume, identifying variables associated with patient discharge destination can expedite placement applications and subsequently reduce hospital length of stay.

Methods. The 2011 to 2014 ACS-NSQIP database was queried using Current Procedural Terminology (CPT) codes 22551 or 22554. Patients were divided into two cohorts based on discharge destination. Bivariate and multivariate logistic regression analyses were employed to identify predictors for patient discharge destination and extended hospital length of stay.

Results. A total of 14,602 patients met the inclusion criteria for the study of which 498 (3.4%) had nonhome discharge. Multivariate logistic regression found that Hispanic versus Black race/ ethnicity (odds ratio, OR¼0.21, 0.05–0.91, P¼0.037), American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander versus Black race/ethnicity (OR¼0.52, 0.34–0.80, p-value¼0.003), White versus Black race/ethnicity (OR¼0.55, 0.42–0.71), elderly age 65 years (OR¼3.32, 2.72–4.06), obesity (OR¼0.77, 0.63–0.93, P¼0.008), diabetes (OR¼1.32, 1.06–1.65, P¼0.013), independent versus partially/totally dependent functional status (OR¼0.11, 0.08–0.15), operation time 4hours (OR¼2.46, 1.87–3.25), cardiac comorbidity (OR ¼1.38, 1.10– 1.72, P ¼0.005), and ASA Class 3 (OR¼2.57, 2.05–3.20) were predictive factors in patient discharge to a facility other than home. In addition, multivariate logistic regression analysis also found nonhome discharge to be the most predictive variable in prolonged hospital length of stay.

Conclusion. Several predictive factors were identified in patient discharge to a facility other than home, many being preoperative variables. Identification of these factors can expedite patient discharge applications and potentially can reduce hospital stay, thereby reducing the risk of hospital acquired conditions and minimizing health care costs.

Level of Evidence: 3

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Epilepsy Surgeries Requiring an Operculoinsular Cortectomy

Neurosurgery 81:602–612, 2017

Epilepsy surgeries requiring an operculoinsulectomy pose significant difficulties because the perisylvian area is highly vascular, deep, and functional.

OBJECTIVE: To report the operative technique and results of epilepsy surgeries requiring an operculoinsular cortectomy at our institution.

METHODS: The data of all consecutive patients who had undergone an epilepsy surgery requiring an operculoinsular cortectomy with a minimum follow-up of 1 yr were reviewed. Tumor and vascular malformation cases were excluded. Surgical techniques are described based on findings during surgery.

RESULTS: Twenty-five patients underwent an epilepsy surgery requiring an operculoinsular cortectomy: mean age at surgery was 35 y (9-51), mean duration of epilepsy was 19 y (5-36), 14were female, and mean duration of follow-up was 4.7 y (1-16).Magnetic resonance imaging of the operculoinsular area was normal or revealed questionable nonspecific findings in 72% of cases. Investigation with intracranial EEG electrodes was done in 17 patients. Surgery was performed on the dominant side for language in 7 patients. An opercular resectionwasperformed inallbut2patientswhoonlyhadan insulectomy.Engel class I seizure control was achieved in 80% of patients. Postoperative neurological deficits (paresis, dysphasia, alteration of taste, smell, hearing, pain, and thermal perceptions) were frequent (75%) but always transient except for 1 patient with persistent mild alteration of thermal and pain perception.

CONCLUSION: Surgical treatment of operculoinsular epilepsy is effective in achieving seizure control and is associated with an acceptable long-term complication rate.

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Patient Selection and Clinical Efficacy of Urgent Superficial Temporal Artery-Middle Cerebral Artery Bypass in Acute Ischemic Stroke Using Advanced Magnetic Resonance Imaging Techniques

Operative Neurosurgery 13:552–559, 2017

Selected patients with acute ischemic stroke might benefit from superficial temporal artery-middle cerebral artery (STA-MCA) bypass, but the indications for urgent STA-MCA bypass are unknown.

OBJECTIVE: To report our experiences of urgent STA-MCA bypass in patients requiring urgent reperfusion who were ineligible for other reperfusion therapies, using advanced magnetic resonance imaging (MRI) techniques.

METHODS: The inclusion criteria for urgent STA-MCA bypass were as follows: acute infarct volume <70 mL with a ratio of perfusion/diffusion lesion volume ≥1.2, and a regional cerebral blood volume ratio >0.85. FromJanuary 2013 to October 2015, 21 urgent STA-MCA bypass surgeries were performed. The control group included 19 patients who did not undergo bypass surgery mainly due to refusal of surgery or the decision of the neurologist. Clinical and radiological data were compared between the surgery and control group.

RESULTS: The median age of the control group (70 years, interquartile range [IQR] 58-76) was higher than that of the surgery group (62 years, IQR 49-66), but the median preoperative diffusion and perfusion lesion volumes of the surgery group (13.8 mL, IQR 7.5-26.0 and 120.9 mL, IQR 84.9-176.0, respectively) were higher than those of the control group (5.6 mL, IQR 2.1-9.1 and 69.7 mL, IQR 23.9-125.3, respectively). Sixteen (76.2%) patients in the surgery group and 2 (10.5%) patients in the control group had favorable outcomes (P < .001). Logistic regression analysis identified bypass surgery as the strongest predictive factor.

CONCLUSION: STA-MCA bypass can be used as a therapeutic tool for acute ischemic stroke.Advanced MRI techniques are helpful for selecting patients and for decision making.

 

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Anterior lumbar discectomy and fusion for acute cauda equina syndrome caused by recurrent disc prolapse

J Neurosurg Spine 27:352–356, 2017

There is a lack of information and consensus regarding the optimal treatment for recurrent disc herniation previously treated by posterior discectomy, and no reports have described an anterior approach for recurrent disc herniation causing cauda equina syndrome (CES). Revision posterior decompression, irrespective of the presence of CES, has been reported to be associated with significantly higher rates of dural tears, hematomas, and iatrogenic nerve root damage.

The authors describe treatment and outcomes in 3 consecutive cases of patients who underwent anterior lumbar discectomy and fusion (ALDF) for CES caused by recurrent disc herniations that had been previously treated with posterior discectomy. All 3 patients were operated on within 12 hours of presentation and were treated with an anterior retroperitoneal lumbar approach. Follow-up ranged from 12 to 24 months. Complete retrieval of herniated disc material was achieved without encountering significant epidural scar tissue in all 3 cases. No perioperative infection or neurological injury occurred, and all 3 patients had neurological recovery with restoration of bladder and bowel function and improvement in back and leg pain.

ALDF is one option to treat CES caused by recurrent lumbar disc prolapse previously treated with posterior discectomy. The main advantage is that it avoids dissection around epidural scar tissue, but the procedure is associated with other risks and further evaluation of its safety in larger series is required.

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