bluuebunny/crossref_metadata_2025 huggingface dataset:
Subtotal resection of cervical schwannomas and growth rate of residual tumors
Authors: Ryu Sung Mo , Lee Sun-Ho , Lee Kyung Min , Eoh Whan , Kim Eun-Sang
Published: February 2019

OBJECTIVE

The objective of this study was to elucidate the features and surgical outcomes of cervical schwannomas.

METHODS

The authors retrospectively reviewed the records of 90 patients who underwent surgically treated cervical schwannomas from January 1995 to December 2017, with an emphasis on MRI findings such as tumor location, tumor size, extent of tumor resection, and growth of a residual tumor.

RESULTS

This study included 51 men (56.7%) and 39 women (43.3%) with a mean age of 44.5 years (range 7–77 years). Dumbbell-shaped tumors comprised 62 (68.9%) of 90 cases and gross-total resection (GTR) was achieved in 59 (65.6%) of 90 cases. All nondumbbell tumors (n = 28) underwent GTR. Only 1 case of recurrence in the GTR group showed a gradual increase in size (by 8.9 mm) during the 150-month follow-up period. For the regrowth patients in the subtotal resection group, the mean percentage increase in tumor size was 47.5% ± 33.1% and the mean growth rate was 5.8 ± 4.6 mm/year during the 20.3-month follow-up period. However, the size of residual tumor spontaneously decreased by a mean of 8.3% ± 11.1% during the 48.4-month follow-up period in the nonregrowth group.

CONCLUSIONS

These findings suggested that frequent MRI follow-up examinations are required for residual schwannomas in the cervical spine for at least 2 years, and continuous MRI follow-ups are also required thereafter.
Astronaut Michael Collins, Apollo 8, and the anterior cervical fusion that changed the history of human spaceflight
Authors: Menger Richard , Wolf Michael , Thakur Jai Deep , Nanda Anil , Martino Anthony
Published: February 2019

In 1961, President John F. Kennedy declared that the United States would send a man to the moon and safely bring him home before the end of the decade. Astronaut Michael Collins was one of those men. He flew to the moon on the historic flight of Apollo 11 while Neil Armstrong and Buzz Aldrin walked on its surface. However, this was not supposed to be the case.

Astronaut Collins was scheduled to fly on Apollo 8. While training, in 1968, he started developing symptoms of cervical myelopathy. He underwent evaluation at Wilford Hall Air Force Hospital in San Antonio and was noted to have a C5–6 disc herniation and posterior osteophyte on myelography. Air Force Lieutenant General (Dr.) Paul W. Myers performed an anterior cervical discectomy with placement of iliac bone graft. As a result, Astronaut James Lovell took his place on Apollo 8 flying the uncertain and daring first mission to the moon. This had a cascading effect on the rotation of astronauts, placing Michael Collins on the Apollo 11 flight that first landed men on the moon. It also placed Astronaut James Lovell in a rotation that exposed him to be the Commander of the fateful Apollo 13 flight.

Here, the authors chronicle the history of Astronaut Collins’ anterior cervical surgery and the impact of his procedure on the rotation of astronaut flight selection, and they review the pivotal historic nature of the Apollo 8 spaceflight. The authors further discuss the ongoing issue of cervical disc herniation among astronauts.
Validation of a methodology for neuro-urological and lumbosacral stimulation studies in domestic pigs: a humanlike animal model
Authors: Guiho Thomas , Azevedo-Coste Christine , Guiraud David , Delleci Claire , Capon Grégoire , Delgado-Piccoli Natalia , Bauchet Luc , Vignes Jean-Rodolphe
Published: February 2019

OBJECTIVE

Spinal cord injuries (SCIs) result in loss of movement and sensory feedback, but also organ dysfunction. Nearly all patients with complete SCI lose bladder control and are prone to kidney failure if intermittent catheterization is not performed. Electrical stimulation of sacral spinal roots was initially considered to be a promising approach for restoring continence and micturition control, but many patients are discouraged by the need for surgical deafferentation as it could lead to a loss of sensory functions and reflexes. Nevertheless, recent research findings highlight the renewed interest in spinal cord stimulation (SCS). It is thought that synergic recruitment of spinal fibers could be achieved by stimulating the spinal neural networks involved in regulating physiological processes. Paradoxically, most of these recent studies focused on locomotor issues, while few addressed visceral dysfunction. This could at least partially be attributed to the lack of methodological tools. In this study, the authors aim to fill this gap by presenting a comprehensive method for investigating the potential of SCS to restore visceral functions in domestic pigs, a large-animal model considered to be a close approximation to humans.

METHODS

This methodology was tested in 7 female pigs (Landrace pig breed, 45–60 kg, 4 months old) during acute experiments. A combination of morphine and propofol was used for anesthesia when transurethral catheterization and lumbosacral laminectomy (L4–S4) were performed. At the end of the operation, spinal root stimulation (L6–S5) and urodynamic recordings were performed to compare the evoked responses with those observed intraoperatively in humans.

RESULTS

Nervous excitability was preserved despite long-term anesthesia (mean 8.43 ± 1.5 hours). Transurethral catheterization and conventional laminectomy were possible while motor responses (gluteus muscle monitoring) were unaffected throughout the procedure. Consistent detrusor (approximately 25 cm H2O) and sphincter responses were obtained, whereas spinal root stimulation elicited detrusor and external urethral sphincter co-contractions similar to those observed intraoperatively in humans.

CONCLUSIONS

Pigs represent an ideal model for SCS studies aimed at visceral function investigation and restoration because of the close similarities between female domestic pigs and humans, both in terms of anatomical structure and experimental techniques implemented. This article provides methodological keys for conducting experiments with equipment routinely used in clinical practice.
Association between lumbar sacralization and increased degree of vertebral slippage and disc degeneration in patients with L4 spondylolysis
Authors: Yao Xinqiang , Ding Ruoting , Liu Junhao , Zhu Siyuan , Zhuang Jingshen , Liu Zhongyuan , Jiang Hui , Qu Dongbin , Zhu Qingan , Chen Jianting
Published: February 2019

OBJECTIVE

The aim of this study was to evaluate the effect of lumbar sacralization on the level of vertebral slip and disc degeneration in patients with L4 spondylolysis.

METHODS

The authors analyzed data from 102 cases in which patients underwent surgical treatment for L4 spondylolysis and spondylolisthesis at their institution between March 2007 and September 2016. Lumbar sacralization was characterized by the presence of pseudarthrosis and/or bony fusion between the L5 transverse process and sacrum, and the type of lumbosacral transitional vertebra (LSTV) was evaluated with the Castellvi classification. The amount of vertebral slippage was measured using the Taillard technique and Meyerding grade. Degeneration of the L4–5 segment was quantified using the Pfirrmann and Modic classifications. Patients were divided into 2 groups based on the presence or absence of sacralization, and the amount of vertebral slip and degeneration of the L4–5 segment was compared between groups.

RESULTS

Lumbar sacralization was present in 37 (36%) of 102 patients with L4 spondylolysis. The LSTV was type IIa in 10 cases, type IIb in 7, type IIIa in 2, and type IIIb in 18. The levels of vertebral slip and disc degeneration in the group of patients with sacralization were significantly greater than in the group without sacralization. No significant difference was found between the 2 groups with respect to Modic changes.

CONCLUSIONS

The increased stability between a sacralized L5 and the sacrum may predispose the L4–5 segment to greater instability and disc degeneration in patients with L4 spondylolysis.
Outcomes and complications of different surgical treatments for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis
Authors: Giordan Enrico , Palandri Giorgio , Lanzino Giuseppe , Murad Mohammad Hassan , Elder Benjamin D.
Published: February 2019

OBJECTIVE

Different CSF diversion procedures (ventriculoperitoneal, ventriculoatrial, and lumboperitoneal shunting) have been utilized for the treatment of idiopathic normal pressure hydrocephalus. More recently, endoscopic third ventriculostomy has been suggested as a reasonable alternative in some studies. The purpose of this study was to perform a systematic review and meta-analysis to assess overall rates of favorable outcomes and adverse events for each of these treatments. An additional objective was to determine the outcomes and complication rates in relation to the type of valve utilized (fixed vs programmable).

METHODS

Multiple databases (PubMed, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus) were searched for studies involving patients with idiopathic ventriculomegaly, no secondary cause of hydrocephalus, opening pressure < 25 mm Hg on high-volume tap or drainage trial, and age > 60 years. Outcomes included the proportion of patients who showed improvement in gait, cognition, and bladder function. Adverse events considered in the analysis included postoperative ischemic/hemorrhagic complications, subdural fluid collections, seizures, need for revision surgery, and infection.

RESULTS

A total of 33 studies, encompassing 2461 patients, were identified. More than 75% of patients experienced improvement after shunting, without significant differences among the different techniques utilized. Overall, gait improvement was observed in 75% of patients, cognitive function improvement in more than 60%, and improvement of incontinence in 55%. Adjustable valves were associated with a reduction in revisions (12% vs 32%) and subdural collections (9% vs 22%) as compared to fixed valves.

CONCLUSIONS

Outcomes did not differ significantly among different CSF diversion techniques, and overall improvement was reported in more than 75% of patients. The use of programmable valves decreased the incidence of revision surgery and of subdural collections after surgery, potentially justifying the higher initial cost associated with these valves.
Comparison of practical methods in clinical sites for estimating cerebral blood flow during balloon test occlusion
Authors: Tani Shoichi , Imamura Hirotoshi , Asai Katsunori , Shimizu Kampei , Adachi Hidemitsu , Tokunaga So , Funatsu Takayuki , Suzuki Keita , Adachi Hiromasa , Kawabata Shuhei , Matsui Yuichi , Sasaki Natsuhi , Akiyama Ryo , Horiuchi Kazufumi , Sakai Chiaki , Sakai Nobuyuki
Published: February 2019

OBJECTIVE

The authors sought to compare methods of measurement for venous phase delay (VPD) or mean stump pressure (MSTP) to rank their potential to predict ischemic tolerance during balloon test occlusion in the internal carotid artery, exploring a more correlative and convenient way to measure cerebral blood flow (CBF) that could be utilized even in the acute phase or in institutions not adequately equipped to measure CBF during the test.

METHODS

X-ray angiography perfusion analysis using diagnostic digital subtraction angiography (DSA) equipment enables 1-step examination (without any room-to-room transfer of patients) to measure CBF, VPD, and MSTP completely simultaneously, which has not been accomplished by any previous perfusion studies.

RESULTS

This analysis was applied to 17 patients and resulted in successful estimation of all 3 parameters in each case. The average VPD of several cortical veins had a strong correlation with relative CBF (rCBF) between bilateral hemispheres with a correlation coefficient of 0.89443, a correlation as strong as that (0.90357) of the “approximate VPD,” which is interpreted based on the trend line of the scatterplot of the time to peak contrast opacification in cortical veins and their spatial positioning from the median sagittal plane. MSTP and classic visual determination of VPD have weaker correlation coefficients with rCBF (0.56119 and 0.70048, respectively). Overall, subjective visual determination in combination with the calculation of the trend line to estimate VPD provided a considerably strong correlation with rCBF (R = 0.86660) without any dedicated software or hardware.

CONCLUSIONS

VPD has a stronger correlation with rCBF than MSTP. rCBF could be successfully predicted on common DSA equipment, even by visual determination without expensive software, if the trend line is adopted for processing to estimate VPD.
Topical vancomycin for neurosurgery wound prophylaxis: an interim report of a randomized clinical trial on drug safety in a diverse neurosurgical population
Authors: Radwanski Ryan E. , Christophe Brandon R. , Pucci Josephine U. , Martinez Moises A. , Rothbaum Michael , Bagiella Emilia , Lowy Franklin D. , Knopman Jared , Connolly E. Sander
Published: February 2019

OBJECTIVE

Postoperative surgical site infections (SSIs) in neurosurgical patients carry a significant risk of increased morbidity and mortality. With SSIs accounting for approximately 20% of nosocomial infections and costing approximately $1.6 billion USD annually, there is a need for additional prophylaxis to improve current standards of care. Topical vancomycin is increasingly utilized in instrumented spinal and cardiothoracic procedures, where it has been shown to reduce the risk of SSIs. A randomized controlled trial assessing its efficacy in the general neurosurgical population is currently underway. Here, the authors report their initial impressions of topical vancomycin safety among patients enrolled during the 1st year of the trial.

METHODS

This prospective, multicenter, patient-blinded, randomized controlled trial will enroll 2632 patients over 5 years. Here, the authors report the incidence of adverse events, the degree of systemic vancomycin absorption in treated patients, and pattern changes of antibiotic-resistant profiles of Staphylococcus aureus flora among patients enrolled during the 1st year.

RESULTS

The topical vancomycin treatment group comprised 257 patients (514 total enrolled patients), of whom 2 exhibited weakly positive serum levels of vancomycin (> 3.0 mg/dl). S. aureus was detected preoperatively in the anterior nares of 35 (18.1%) patients and the skin near the surgical site of 9 (4.7%). Colonization in the nares remained for many patients (71.4%) through postoperative day 30. The authors found a significant association between preoperative S. aureus colonization and postoperative colonization. Seven methicillin-resistant isolates were detected among 6 different patients. Two isolates were detected preoperatively, and 5 were de novo postoperative colonization. No adverse responses to treatment have been reported to date.

CONCLUSIONS

The authors’ data indicate that the use of topical vancomycin is safe with no significant adverse effects and minimal systemic absorption, and no development of vancomycin-resistant microorganisms.

Clinical trial registration no.: NCT02284126 (clinicaltrials.gov)
Management of recurrent intracranial aneurysms after coil embolization: a novel classification scheme based on angiography
Authors: Yu Le-Bao , Yang Xin-Jian , Zhang Qian , Zhang Shao-Sen , Zhang Yan , Wang Rong , Zhang Dong
Published: February 2019

OBJECTIVE

Recurrent aneurysms after coil embolization remain a challenging issue. The goal of the present study was to report the authors’ experience with recurrent aneurysms after coil embolization and to discuss the radiographic classification scheme and recommended management strategy.

METHODS

Aneurysm treatments from a single institution over a 6-year period were retrospectively reviewed. Ninety-seven aneurysms that recurred after initial coiling were managed during the study period. Recurrent aneurysms were classified into the following 5 types based on their angiographic characteristics: I, pure recanalization inside the aneurysm sac; II, pure coil compaction without aneurysm growth; III, new aneurysm neck formed without coil compaction; IV, new aneurysm neck formed with coil compaction; and V, newly formed aneurysm neck and sac.

RESULTS

Aneurysm recurrences resulted in rehemorrhages in 6 cases (6.2%) of type III–V aneurysms, but in none of type I–II aneurysms. There was a significantly higher proportion of ophthalmic artery aneurysms and complex internal carotid artery aneurysms presenting as types I and II than presented as the other 3 types (63.3% vs 16.4%, p < 0.001). In contrast, for posterior communicating artery aneurysms and anterior communicating artery aneurysms, a higher proportion of type III–V aneurysms was observed than for the other 2 types, but without a significant difference in the multivariate model (56.7% vs 23.3%). In addition, giant (> 25 mm) aneurysms were more common among type I and II lesions than among type III and IV aneurysms (36.7% vs 9.0%, p = 0.001), which exhibited a higher proportion of small (< 10 mm) lesions (65.7% vs 13.3%, p < 0.001). A single reembolization procedure was sufficient to occlude 80.0% of type I recurrences and 83.3% of type II recurrences from coil compaction but only 65.6% of type III–V recurrences from aneurysm regrowth.

CONCLUSIONS

Aneurysm size and location represent the determining factors of the angiographic recurrence types. Type I and II recurrences were safely treated by reembolization, whereas type III–V recurrences may be best managed surgically when technically feasible.
Endoscopic transorbital surgery for Meckel’s cave and middle cranial fossa tumors: surgical technique and early results
Authors: Jeon Chiman , Hong Chang-Ki , Woo Kyung In , Hong Sang Duk , Nam Do-Hyun , Lee Jung-Il , Choi Jung Won , Seol Ho Jun , Kong Doo-Sik
Published: February 2019

OBJECTIVE

Tumors involving Meckel’s cave remain extremely challenging because of the surrounding complex neurovascular structures and deep-seated location. The authors investigated a new minimal-access technique using the endoscopic transorbital approach (eTOA) through the superior eyelid crease to Meckel’s cave and middle cranial fossa lesions and reviewed the most useful surgical procedures and pitfalls of this approach.

METHODS

Between September 2016 and January 2018, the authors performed eTOA in 9 patients with tumors involving Meckel’s cave and the middle cranial fossa. The lesions included trigeminal schwannoma in 4 patients, meningioma in 2 patients, metastatic brain tumor in 1 patient, chondrosarcoma in 1 patient, and dermoid cyst in 1 patient. In 7 of the 9 patients, eTOA alone was performed, while the other 2 patients underwent a combined eTOA and endoscopic endonasal approach or retrosigmoid craniotomy. Data including details of surgical techniques and clinical outcomes were recorded.

RESULTS

Gross-total resection was performed in 7 of the 9 patients (77.8%). Four patients underwent extended eTOA (with lateral orbital rim osteotomy). Drilling of the trapezoid sphenoid floor, a middle fossa “peeling” technique, and full visualization of Meckel’s cave were applied to approach the lesions. Tumors were exposed and removed extradurally in 3 patients and intradurally in 6 patients. There was no postoperative CSF leak.

CONCLUSIONS

The eTOA affords a direct route to access Meckel’s cave and middle cranial fossa lesions. With experience, this novel approach can be successfully applied to selected skull base lesions. To achieve successful removal of the tumor, emphasis should be placed on the importance of adequately removing the greater sphenoid wing and vertical crest. However, because of limited working space eTOA may not be an ideal approach for posterior fossa lesions.
Surgical management and prognostic factors for primary intracranial myxoma: a single-institute experience with a systematic review
Authors: Weng Jian-Cong , Song Lai-Rong , Li Da , Wang Liang , Wu Zhen , Wang Jun-Mei , Li Gui-Lin , Jia Wang , Zhang Li-Wei , Zhang Jun-Ting
Published: February 2019

OBJECTIVE

Primary intracranial myxomas (PICMs) are extremely rare neoplasms, and their management and prognostic factors remain ambiguous. The authors aimed to elaborate the radiological features, evaluate the risk factors for progression-free survival (PFS), and propose a treatment protocol based on pooled data from cases treated at their institute and those found in the literature.

METHODS

Clinical data from all cases of PICMs treated at the authors’ institute and those cases reported in the English-language literature between 1987 and December 2017 were reviewed. The authors searched the Ovid MEDLINE, Embase, PubMed, and Cochrane databases using the keywords “myxoma” and “central nervous system,” “intracranial,” “cerebral,” “skull base,” “skull,” or “brain.” Previously published data were processed and used according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Risk factors in the pooled cohort were evaluated.

RESULTS

Cases from the authors’ institute included 21 males and 9 females, with a mean age of 35.7 ± 1.7 years. Gross-total resection (GTR) and non-GTR were achieved in 6 (20.0%) and 24 (80.0%) patients, respectively. After a mean follow-up of 86.7 ± 14.1 months, recurrence occurred in 6 (24%) patients, for a median PFS time of 85.2 months (range 36.0–136.0 months) and no deaths. In the literature between 1987 and 2017, 35 cases of PICM were identified in 14 males and 21 females with a mean age of 31.7 ± 3.2 years. GTR and non-GTR were achieved in 23 (65.7%) and 9 (25.7%) cases, respectively. After a mean follow-up of 25.8 ± 6.9 months (range 1.0–156.0 months), recurrence occurred in 4 (14.3%) patients, for a median PFS time of 11.0 months (range 3.0–36.0 months) and no deaths. Actuarial PFS rates at 1, 5, and 10 years were 93.0%, 80.6%, and 67.9%, respectively. A multivariate model demonstrated that GTR (HR 0.058, 95% CI 0.005–0.680, p = 0.023) was the only factor that favored PFS.

CONCLUSIONS

PICMs are rare neoplasms with a slightly higher occurrence in males. GTR was the only favorable factor for PFS. Based on statistical results, GTR alone, if tolerable, is advocated as the optimal treatment for PICM. Nevertheless, conservative excision may be preferred to avoid damage to vital structures. PICMs have a tendency to recur within a few years of the initial surgery if resection is incomplete; therefore, close postoperative follow-up is mandatory. Future studies with larger cohorts are necessary to verify the study findings.

Systematic review registration no.: CRD42018091517 (www.crd.york.ac.uk/prospero/)
Using artificial neural networks to identify patients with concussion and postconcussion syndrome based on antisaccades
Authors: Landry Alexander P. , Ting Windsor K. C. , Zador Zsolt , Sadeghian Alireza , Cusimano Michael D.
Published: February 2019

OBJECTIVE

Artificial neural networks (ANNs) have shown considerable promise as decision support tools in medicine, including neurosurgery. However, their use in concussion and postconcussion syndrome (PCS) has been limited. The authors explore the value of using an ANN to identify patients with concussion/PCS based on their antisaccade performance.

METHODS

Study participants were prospectively recruited from the emergency department and head injury clinic of a large teaching hospital in Toronto. Acquaintances of study participants were used as controls. Saccades were measured using an automated, portable, head-mounted device preprogrammed with an antisaccade task. Each participant underwent 100 trials of the task and 11 saccade parameters were recorded for each trial. ANN analysis was performed using the MATLAB Neural Network Toolbox, and individual saccade parameters were further explored with receiver operating characteristic (ROC) curves and a logistic regression analysis.

RESULTS

Control (n = 15), concussion (n = 32), and PCS (n = 25) groups were matched by age and level of education. The authors examined 11 saccade parameters and found that the prosaccade error rate (p = 0.04) and median antisaccade latency (p = 0.02) were significantly different between control and concussion/PCS groups. When used to distinguish concussion and PCS participants from controls, the neural networks achieved accuracies of 67% and 72%, respectively. This method was unable to distinguish study patients with concussion from those with PCS, suggesting persistence of eye movement abnormalities in patients with PCS. The authors’ observations also suggest the potential for improved results with a larger training sample.

CONCLUSIONS

This study explored the utility of ANNs in the diagnosis of concussion/PCS based on antisaccades. With the use of an ANN, modest accuracy was achieved in a small cohort. In addition, the authors explored the pearls and pitfalls of this novel approach and identified important future directions for this research.
Interdural course of the ophthalmic artery in the optic canal
Authors: Tayebi Meybodi Ali , Borba Moreira Leandro , Lawton Michael T. , Eschbacher Jennifer M. , Belykh Evgenii G. , Felicella Michelle M. , Preul Mark C.
Published: February 2019

OBJECTIVE

In the current neurosurgical and anatomical literature, the intracanalicular segment of the ophthalmic artery (OphA) is usually described to be within the optic nerve dural sheath (ONDS), implying direct contact between the nerve and the artery inside the optic canal. In the present study, the authors sought to clarify the exact relationship between the OphA and ONDS.

METHODS

Ten cadaveric heads were subjected to endoscopic endonasal and transcranial exposures of the OphA in the optic canal (5 for each approach). The relationship between the OphA and ONDS was assessed. Histological examination of one specimen of the optic nerve and the accompanying OphA was also performed to confirm the relationship with the ONDS.

RESULTS

In all specimens, the OphA coursed between the two layers of the dura (endosteal and meningeal) and was not in direct contact with the optic nerve, except for the first few millimeters of the proximal optic canal before it pierced the ONDS. Upon reaching the orbit, the two layers of the dura separated and allowed the OphA to literally float within the orbital fat. The meningeal dura continued as the ONDS, whereas the endosteal dura became the periorbita.

CONCLUSIONS

This study clarifies the interdural course of the OphA within the optic canal. This anatomical nuance has important neurosurgical implications regarding safe exposure and manipulation of the OphA.
Preoperative stereotactic radiosurgery before planned resection of brain metastases: updated analysis of efficacy and toxicity of a novel treatment paradigm
Authors: Prabhu Roshan S. , Miller Katherine R. , Asher Anthony L. , Heinzerling John H. , Moeller Benjamin J. , Lankford Scott P. , McCammon Robert J. , Fasola Carolina E. , Patel Kirtesh R. , Press Robert H. , Sumrall Ashley L. , Ward Matthew C. , Burri Stuart H.
Published: February 2019

OBJECTIVE

Preoperative stereotactic radiosurgery (SRS) is a feasible alternative to postoperative SRS and may lower the risk of radiation necrosis (RN) and leptomeningeal disease (LMD) recurrence. The study goal was to report the efficacy and toxicity of preoperative SRS in an expanded patient cohort with longer follow-up period relative to prior reports.

METHODS

The records for patients with brain metastases treated with preoperative SRS and planned resection were reviewed. Patients with classically radiosensitive tumors, planned adjuvant whole brain radiotherapy, or no cranial imaging at least 1 month after surgery were excluded. Preoperative SRS dose was based on lesion size and was reduced approximately 10–20% from standard dosing. Surgery generally followed within 48 hours.

RESULTS

The study cohort consisted of 117 patients with 125 lesions treated with single-fraction preoperative SRS and planned resection. Of the 117 patients, 24 patients were enrolled in an initial prospective trial; the remaining 93 cases were consecutively treated patients who were retrospectively reviewed. Most patients had a single brain metastasis (70.1%); 42.7% had non–small cell lung cancer, 18.8% had breast cancer, 15.4% had melanoma, and 11.1% had renal cell carcinoma. Gross total resection was performed in 95.2% of lesions. The median time from SRS to surgery was 2 days, the median SRS dose was 15 Gy, and the median gross tumor volume was 8.3 cm3. Event cumulative incidence at 2 years was as follows: cavity local recurrence (LR), 25.1%; distant brain failure, 60.2%; LMD, 4.3%; and symptomatic RN, 4.8%. The median overall survival (OS) and 2-year OS rate were 17.2 months and 36.7%, respectively. Subtotal resection (STR, n = 6) was significantly associated with increased risk of cavity LR (hazard ratio [HR] 6.67, p = 0.008) and worsened OS (HR 2.63, p = 0.05) in multivariable analyses.

CONCLUSIONS

This expanded and updated analysis confirms that single-fraction preoperative SRS confers excellent cavity local control with very low risk of RN or LMD. Preoperative SRS has several potential advantages compared to postoperative SRS, including reduced risk of RN due to smaller irradiated volume without need for cavity margin expansion and reduced risk of LMD due to sterilization of tumor cells prior to spillage at the time of surgery. Subtotal resection, though infrequent, is associated with significantly worse cavity LR and OS. Based on these results, a randomized trial of preoperative versus postoperative SRS is being designed.
Terminal spreading depolarizations causing electrocortical silencing prior to clinical brain death: case report
Authors: Carlson Andrew P. , Shuttleworth C. William , Major Sebastian , Lemale Coline L. , Dreier Jens P. , Hartings Jed A.
Published: February 2019

The authors report on a 57-year-old woman in whom progression to brain death occurred on day 9 after aneurysmal subarachnoid hemorrhage without evidence of significant brain edema or vasospasm. Neuromonitoring demonstrated that brain death was preceded by a series of cortical spreading depolarizations that occurred in association with progressive hypoxic episodes. The depolarizations induced final electrical silence in the cortex and ended with a terminal depolarization that persisted > 7 hours. To the authors’ knowledge, this is the first report of terminal spreading depolarization in the human brain prior to clinical brain death and major cardiopulmonary failure.
Targeting IL-13Rα2 for effective treatment of malignant peripheral nerve sheath tumors in mouse models
Authors: Mrowczynski Oliver D. , Payne Russell A. , Bourcier Alexandre J. , Mau Christine Y. , Slagle-Webb Becky , Shenoy Ganesh , Madhankumar Achuthamangalam B. , Abramson Stephan B. , Wolfe Darren , Harbaugh Kimberly S. , Rizk Elias B. , Connor James R.
Published: February 2019

OBJECTIVE

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas that harbor a high potential for metastasis and have a devastating prognosis. Combination chemoradiation aids in tumor control and decreases tumor recurrence but causes deleterious side effects and does not extend long-term survival. An effective treatment with limited toxicity and enhanced efficacy is critical for patients suffering from MPNSTs.

METHODS

The authors recently identified that interleukin-13 receptor alpha 2 (IL-13Rα2) is overexpressed on MPNSTs and could serve as a precision-based target for delivery of chemotherapeutic agents. In the work reported here, a recombinant fusion molecule consisting of a mutant human IL-13 targeting moiety and a point mutant variant of Pseudomonas exotoxin A (IL-13.E13 K-PE4E) was utilized to treat MPNST in vitro in cell culture and in an in vivo murine model.

RESULTS

IL-13.E13 K-PE4E had a potent cytotoxic effect on MPNST cells in vitro. Furthermore, intratumoral administration of IL-13.E13 K-PE4E to orthotopically implanted MPNSTs decreased tumor burden 6-fold and 11-fold in late-stage and early-stage MPNST models, respectively. IL-13.E13 K-PE4E treatment also increased survival by 23 days in the early-stage MPNST model.

CONCLUSIONS

The current MPNST treatment paradigm consists of 3 prongs: surgery, chemotherapy, and radiation, none of which, either singly or in combination, are curative or extend survival to a clinically meaningful degree. The results presented here provide the possibility of intratumoral therapy with a potent and highly tumor-specific cytotoxin as a fourth treatment prong with the potential to yield improved outcomes in patients with MPNSTs.
Functional connectivity analysis and prediction of cognitive change after carotid artery stenting
Authors: Tani Naoki , Yaegaki Takahide , Nishino Akio , Fujimoto Kenta , Hashimoto Hiroyuki , Horiuchi Kaoru , Nishiguchi Mitsuhisa , Kishima Haruhiko
Published: February 2019

OBJECTIVE

The neurocognitive course of patients who have undergone cerebral revascularization has been the subject of many studies, and the reported effects of carotid artery stenting (CAS) on cognitive function have varied from study to study. The authors hypothesized that cognitive amelioration after CAS is associated with alteration of the default mode network (DMN) connectivity, and they investigated the correlation between functional connectivity (FC) of the DMN and post-CAS changes in cognitive function in order to find a clinical marker that can be used to predict the effect of cerebral revascularization on patients’ cognitive function in this preliminary exploratory study.

METHODS

The authors examined post-CAS changes in cognitive function in relation to FC in patients treated for unilateral carotid artery stenosis. Resting-state functional MRI (rs-fMRI) was performed with a 3-T scanner before and 6 months after CAS in 8 patients. Neuropsychological tests (Wechsler Adult Intelligence Scale III and Wechsler Memory Scale–Revised) were administered to each patient before and 6 months after CAS. The DMN was mapped for each patient through independent component analysis of the rs-fMR images, and the correlation between FC of the DMN and post-CAS change in cognitive function was analyzed on a voxel level. Multivariable regression analysis was performed to identify preoperative factors associated with a post-CAS change in cognitive function.

RESULTS

Post-CAS cognitive function varied between patients and between categories of neuropsychological tests. Although there was no significant overall improvement in Working Memory scores after CAS, post-CAS Working Memory scores changed in negative correlation with changes in FC between the DMN and the precentral/superior frontal gyrus and between the DMN and the middle frontal gyrus. In addition, the preoperative FC between those areas correlated positively with the post-CAS improvement in working memory.

CONCLUSIONS

FC between the DMN and working memory–related areas is closely associated with improvement in working memory after CAS. Preoperative analysis of FC of the DMN may be useful for predicting postoperative improvement in the working memory of patients being treated for unilateral stenosis of the extracranial internal carotid artery.

Clinical trial registration no.: UMIN000020045 (www.umin.ac.jp/ctr/index.htm)
Clinically applicable delineation of the pallidal sensorimotor region in patients with advanced Parkinson’s disease: study of probabilistic and deterministic tractography
Authors: Muller Jennifer , Alizadeh Mahdi , Mohamed Feroze B. , Riley Jonathan , Pearce John J. , Trieu Benjamin , Liang Tsao-Wei , Romo Victor , Sharan Ashwini , Wu Chengyuan
Published: February 2019

OBJECTIVE

Deep brain stimulation (DBS) is an effective procedure in improving motor symptoms for patients with advanced Parkinson’s disease (PD) through the use of high-frequency stimulation. Although one of the most commonly used target sites for DBS, sensorimotor regions of the globus pallidus interna (GPi) have yet to be thoroughly described with advanced neuroimaging analysis in vivo for human subjects. Furthermore, many imaging studies to date have been performed in a research setting and bring into question the feasibility of their applications in a clinical setting, such as for surgical planning. This study compares two different tractography methods applied to clinically feasible acquisition sequences in identifying sensorimotor regions of the GPi and the subthalamic nucleus (STN) in patients with advanced PD selected to undergo DBS.

METHODS

Seven patients with refractory PD selected for DBS were examined by MRI. Diffusion images were acquired with an average acquisition time of 15 minutes. Probabilistic and deterministic tractography methods were applied to each diffusion-weighted data set using FSL and MRtrix, respectively. Fiber assignment was performed using combined sensorimotor areas as initiation seeds and the STN and GPi, separately, as inclusion masks. Corticospinal tracts were excluded by setting the cerebral peduncles as exclusion masks. Variability between proposed techniques was shown using center of gravity (CoG) coordinates.

RESULTS

Deterministic and probabilistic corticopallidal and corticosubthalamic pathways were successfully reconstructed for all subjects across all target sites (bilaterally). Both techniques displayed large connections between the sensorimotor cortex with the posterolateral aspect of the ipsilateral GPi and the posterosuperolateral aspect of the ipsilateral STN. The average variability was 2.67 mm, with the probabilistic method identifying the CoG consistently more posterior and more lateral than the deterministic method.

CONCLUSIONS

Successful delineation of the sensorimotor regions in both the GPi and STN is achievable within a clinically reasonable timeframe. The techniques described in this paper may enhance presurgical planning with increased accuracy and improvement of patient outcomes in patients undergoing DBS. The variability found between tracking techniques warrants the use of the probabilistic tractography method over the deterministic method for presurgical planning. Probabilistic tractography was found to have an advantage over deterministic tractography in its sensitivity, in accurately describing previously described tracts, and in its ability to detect a larger number of fibers.
Flow diversion treatment of complex bifurcation aneurysms beyond the circle of Willis: complications, aneurysm sac occlusion, reabsorption, recurrence, and jailed branch modification at follow-up
Authors: Michelozzi Caterina , Darcourt Jean , Guenego Adrien , Januel Anne-Christine , Tall Philippe , Gawlitza Matthias , Bonneville Fabrice , Cognard Christophe
Published: February 2019

OBJECTIVE

The purpose of this study is to present the authors’ medium-term results, with special emphasis on complications, occlusion rate of the aneurysm sac (digital subtraction angiography [DSA] and MRI), and the fate of cortical branches and perforating arteries covered (“jailed”) by the flow diverter (FD) stent.

METHODS

Between January 2010 and September 2017, 29 patients (14 female) with 30 aneurysms were treated with an FD stent. Twenty-one aneurysms were at the middle cerebral artery bifurcation, 8 were in the anterior communicating artery region, and 1 was a pericallosal artery bifurcation. Thirty-five cortical branches were covered. A single FD stent was used in all patients. Symptomatic and asymptomatic periprocedural and delayed complications were reported. DSA and MRI controls were analyzed to evaluate modification of the aneurysm sac and jailed branches.

RESULTS

Permanent morbidity was 3.4% (1/29), due to a jailed branch occlusion, with a modified Rankin Scale (mRS) score of 2 at the last follow-up. Mortality and permanent complication with poor prognosis (mRS score > 2) rates were 0%. The mean follow-up time for DSA and MRI (mean ± SD) was 21 ± 14.5 months (range 3–66 months) and 19 ± 16 months (range 3–41 months), respectively. The mean time to aneurysm sac occlusion (available for 24 patients), including stable remodeling, was 11.8 ± 6 months (median 13, range 3–27 months). The overall occlusion rate was 82.1% (23/28), and it was 91.7% (22/24) in the group of patients with at least 2 DSA control sequences. One recanalization occurred at 41 months posttreatment. At the time of publication, at the latest follow-up, 7 (20%) of 35 covered branches were occluded, 18 (51.4%) showed a decreased caliber, and the remaining 10 (28.5%) were unchanged. MRI T2-weighted sequences showed complete sac reabsorption in 7/29 aneurysms (24.1%), and the remaining lesions were either smaller (55.2%) or unchanged (17.2%). MRI revealed asymptomatic and symptomatic ischemic events in perforator territories in 7/28 (25%) and 4/28 (14.3%) patients, respectively, which were reversible within 24 hours.

CONCLUSIONS

Flow diversion of bifurcation aneurysms is feasible, with low rates of permanent morbidity and mortality and high occlusion rates; however, recurrence may occur. Caliber reduction and asymptomatic occlusion of covered cortical branches as well as silent perforator stroke are common. Ischemic complications may occur with no identified predictable factors. MRI controls should be required in all patients to evaluate silent ischemic lesions and aneurysm sac reabsorption over time.
Biomechanics of a novel reversibly expandable dynamic craniotomy bone flap fixation plate
Authors: Khanna Rohit , Ferrara Lisa , Khanna Sohit
Published: February 2019

OBJECTIVE

Biomechanical evaluation of a novel expandable cranial fixation plate was assessed in cadavers. The dynamic craniotomy procedure uses low-profile reversibly expandable plates that allow cranial decompression by providing for intracranial volume expansion without removal of the bone flap. The plates allow reversible outward movement of the bone flap upon an increase in intracranial pressure (ICP) and also retract the bone flap and prevent it from sinking inside the cranium once the ICP normalizes.

METHODS

A comparative evaluation of the extent of ICP control with an increase in intracranial volume between various bone flap fixation techniques was undertaken along with testing of the expandable plate compliance. Static compression tests of the plates were performed to assess bone flap fixation and prevention of sinking. Quasi-static shear tension testing of the plates was undertaken to test the tolerance of the plates for expansion. Fatigue shear tension evaluation of the plates was undertaken to assess tolerance for repetitive expansion and contraction.

RESULTS

The dynamic craniotomy provided superior control of ICP with an increase in intracranial volume compared to the hinged craniotomy and standard craniotomy techniques (p < 0.001). Static compression results revealed that the plates withstood bone flap sinkage with a mean peak load of 643.3 ± 26.1 N and a mean inward bone flap displacement of 1.92 ± 0.09 mm. Static shear tension results indicated that the plates could withstand a peak expansion of 71.6 mm. Dynamic shear tension testing of the plates with repetitive 15-mm outward expansion and retraction for a total of up to 500 cycles revealed no cracking and no failure points.

CONCLUSIONS

The reversibly expandable plates provide for a low-profile bone flap fixation with rigid restriction of bone flap sinking and also enable cranial decompression with a high tolerance for repetitive expansion and contraction.
Nerve stretching: a history of tension
Authors: Mahan Mark A.
Published: February 2019

Stretch injuries are among the most devastating forms of peripheral nerve injury; unfortunately, the scientific understanding of nerve biomechanics is widely and impressively conflicting. Experimental models are unique and disparate, victim to different testing conditions, and thus yield gulfs between conclusions. The details of the divergent reports on nerve biomechanics are essential for critical appraisal as we try to understand clinical stretch injuries in light of research evidence. These conflicts preclude broad conclusion, but they highlight a duality in thought on nerve stretch and, within the details, some agreement exists. To synthesize trends in nerve stretch understanding, the author describes the literature since its introduction in the 19th century. Research has paralleled clinical inquiry, so nerve research can be divided into epochs based largely on clinical or scientific technique. The first epoch revolves around therapeutic nerve stretching—a procedure known as neurectasy—in the late 19th century. The second epoch involves studies of nerves repaired under tension in the early 20th century, often the result of war. The third epoch occurs later in the 20th century and is notable for increasing scientific refinement and disagreement. A fourth epoch of research from the 21st century is just dawning. More than 150 years of research has demonstrated a stable and inherent duality: the terribly destructive impact of stretch injuries, as well as the therapeutic benefits from nerve stretching. Yet, despite significant study, the precise border between safe and damaging stretch remains an enigma.
Comparative effectiveness analysis of Pipeline device versus coiling in unruptured aneurysms smaller than 10 mm
Authors: Malhotra Ajay , Wu Xiao , Miller Timothy , Matouk Charles C. , Sanelli Pina , Gandhi Dheeraj
Published: February 2019

OBJECTIVE

Both endovascular coiling and the Pipeline embolization device (PED) have been shown to be safe and clinically effective for treatment of small (< 10 mm) aneurysms. The authors conducted a comparative effectiveness analysis to compare the utility of these treatment methods in terms of health benefits.

METHODS

A decision-analytical study was performed with Markov modeling methods to simulate patients with small unruptured aneurysms undergoing endovascular coiling, stent-assisted coiling (SAC), or PED placement for treatment. Input probabilities were derived from prior literature, and 1-way, 2-way, and probabilistic sensitivity analyses were performed to assess model and input parameter uncertainty.

RESULTS

The base case calculation for a 50-year-old man reveals PED to have a higher health benefit (17.48 quality-adjusted life years [QALYs]) than coiling (17.44 QALYs) or SAC (17.36 QALYs). PED is the better option in 6020 of the 10,000 iterations in probabilistic sensitivity analysis. When the retreatment rate of PED is lower than 9.53%, and the coiling retreatment is higher than 15.6%, PED is the better strategy. In the 2-way sensitivity analysis varying the retreatment rates from both treatment modalities, when the retreatment rate of PED is approximately 14% lower than the retreatment rate of coiling, PED is the more favorable treatment strategy. Otherwise, coiling is more effective. SAC may be better than PED when the unfavorable outcome risk of SAC is lower than 70% of its reported current value.

CONCLUSIONS

With the increasing use of PEDs for treatment of small unruptured aneurysms, the current study indicates that these devices may have higher health benefits due to lower rates of retreatment compared to both simple coiling and stent-assisted techniques. Longer follow-up studies are needed to document the rates of recurrence and retreatment after coiling and PED to assess the cost-effectiveness of these strategies.