Frameless versus frame-based stereotactic radiosurgery for intracranial arteriovenous malformations: A propensity-matched analysis.

Objective: The frameless linear accelerator (LINAC) based stereotactic radiosurgery (SRS) has been evolving with a reduction in patient discomfort. However, there was limited evidence comparing frame-based and frameless SRS for intracranial arteriovenous malformations (AVM). We aimed to compare the treatment outcomes between frame-based and frameless LINAC SRS. Materials and Methods: This retrospective cohort compared the outcomes of frame-based LINAC SRS (1998-2009) with frameless LINAC SRS (2010-2020). The primary outcome was the obliteration rate. The other outcomes included the neurological, radiological, and functional outcomes after SRS. A matched cohort was identified by propensity scores for further comparisons. Results: A total of 65 patients were included with a mean follow-up time of 13.2 years (158.5 months). There were 40 patients in the frame-based group and 25 patients in the frameless group. The overall obliteration rate was comparable (Frame-based 82.5% vs Frameless 80.0%, p = 0.310) and not significantly different over time (log-rank p = 0.536). The crude post-SRS hemorrhage rate was 1.5% and the incidence was 0.3 per 100 person-years. There were 67.7% of patients with AVM obliteration without new persistent neurological deficits at the last visit and 56.9% of patients with AVM obliteration without any deficits (transient or persistent) during the entire follow-up period. Four patients (8.0%) developed late onset persistent adverse radiation effects (more than 96 months after SRS) among 50 patients with more than 8-year surveillance. In the propensity-matched cohort of 42 patients, there was no significant difference in AVM obliteration (Frame-based vs Frameless, log-rank p = 0.984). Conclusion: Frameless and frame-based LINAC SRS have comparable efficacy in intracranial AVM obliteration. A longer follow-up duration may further characterize the rate of late adverse radiation effects in frameless SRS.

Multidimensional Outcomes of Selective Dorsal Rhizotomy for Children With Spastic Cerebral Palsy: Single-Level Laminectomy vs Multiple-Level Laminotomy Techniques.

BACKGROUND: Selective dorsal rhizotomy (SDR) reduces lower limb spasticity, improves gait patterns, and restores normal physical and social activity in children with spastic cerebral palsy. Single-level laminectomy (SLL) and multiple-level laminotomy (MLL) are 2 surgical approaches for SDR with limited clinical data comparing their postoperative outcomes. OBJECTIVE: To compare the differences in multidimensional outcomes after SDR between SLL and MLL for children with spastic cerebral palsy. METHODS: We retrospectively reviewed children who underwent SDR in our hospital from 1997 to 2016. The multidimensional outcomes in spasticity, joint range of motions, gait kinetics, gross motor activities, functional outcomes, and urological outcomes were assessed 1 year postoperatively. Hip dysplasia and scoliosis rate were compared as long-term outcomes. RESULTS: Sixty children underwent SDR, including 34 SLL patients and 26 MLL patients. Most improvements in multidimensional outcomes were comparable between SLL and MLL. Patients in the SLL group had larger improvements in ankle dorsiflexion in the midstance phase (SLL 7.59° ± 11.48° vs MLL 0.29° ± 11.30°, P = .027). The rate of scoliosis was similar between the 2 surgical approaches (SLL 12.1% vs MLL 15.4%, P = .722). CONCLUSION: SDR for children with spastic cerebral palsy could provide physical, functional, and urological improvements. SLL achieved a higher degree of improvement in ankle dorsiflexion in the midstance phase. The rate of scoliosis was not significantly increased by multiple-level laminotomy.

Far Lateral Approach for Disconnection of Craniocervical Junction Dural Arteriovenous Fistula Presented with Myelopathy and Hydrocephalus.

We report a case of craniocervical junction dural arteriovenous fistula (dAVF) presented with myelopathy and normal pressure hydrocephalus, and was treated with hybrid approach of embolization and surgical disconnection. A 68-year-old gentleman presented with 1 year history of unsteady gait and sphincter disturbance. Magnetic resonance imaging (MRI) showed abnormally enlarged and tortuous vessels over right cerebellomedullary cistern. Digital subtraction angiogram (DSA) showed Cognard's type-V dAVF at craniocervical junction. Catheter embolization was performed via external carotid artery and finally surgical disconnection was done with far lateral approach ( Fig. 1 ). Postoperative DSA showed no more arteriovenous shunting ( Fig. 2 ). Clinically the patient improved after a course of rehabilitation. Dural AVF at craniocervical junction is rare and its clinical presentation can be highly variable from subarachnoid hemorrhage to brainstem dysfunction. Identification of the exact fistula site is essential in surgical planning. Surgery is effective and safe to achieve complete obliteration and good clinical outcome. 1 2 3 4 5 6 The link to the video can be found at: https://youtu.be/xI48stSlWpY .

Newly-Diagnosed, Histologically-Confirmed Central Nervous System Tumours in a Regional Hospital in Hong Kong : An Epidemiological Study of a 21-Year Period.

OBJECTIVE: To investigate the epidemiology of newly-diagnosed, histologically-confirmed (NDHC) central nervous system (CNS) tumours and its changes over a 21-year period in a regional hospital in Hong Kong. METHODS: This is a single-institute retrospective descriptive study of patients undergoing surgery for CNS tumours in a regional hospital of Hong Kong in the period from January 1996 to December 2016. The histological definition of CNS tumours was according to the World Health Organization classification, while the site definition for case ascertainment of CNS tumours was as set out by the Central Brain Tumour Registry of the United States. Patients of any age, who had NDHC CNS tumours, either primary or secondary, were included. The following parameters of the patients were retrieved : age at diagnosis, gender, tumour location, and histological diagnosis. Population data were obtained from sources provided by the Government of Hong Kong. The incident rate, estimated by the annual number of cases per 100000 population, for each histology grouping was calculated. Statistical analyses, both including and excluding brain metastases, were performed. Statistical analysis was performed with Microsoft Excel, 2016 (Microsoft, Redmond, WA, USA). RESULTS: Among the 2134 cases of NDHC CNS tumours, there were 1936 cases of intracranial tumours and 198 cases of spinal tumours. The annual number of cases per 100000 population of combined primary intracranial and spinal CNS tumours was 3.6 in 1996, and 11.1 in 2016. Comparing the 5-year average annual number of cases per 100000 population of primary CNS tumours from the period 1996-2000 to 2011-2015, there was an 88% increase, which represent an increase in the absolute number of cases by 4.52 cases/100000 population. This increase was mainly contributed by benign histologies. In the aforementioned periods, meningiomas increased by 1.45 cases/100000 population; schwannomas by 1.05 cases/100000 population, and pituitary adenomas by 0.91 cases/100000 population. While gliomas had a fluctuating 5-year average annual number of cases per 100000 population, it only had an absolute increase of 0.51 cases/100000 population between the 2 periods, which was mainly accounted for by the change in glioblastomas. CONCLUSION: This retrospective study of CNS tumour epidemiology revealed increasing trends in the incidences of several common CNS tumour histologies in Hong Kong, which agrees with the findings in large-scale studies in Korea and the United States. It is important for different geographic locations to establish their own CNS tumour registry with well-defined and structured data collection and analysis system to meet the international standards.

The importance of aspirin, catheterization accuracy, and catheter design in external ventricular drainage-related hemorrhage: a multicenter study of 1002 procedures.

BACKGROUND: External ventricular drainage (EVD) is the commonest neurosurgical procedure performed in daily neurosurgical practice, but relatively few studies have investigated the incidence and risk factors of its related hemorrhagic complications. METHODS: This was a multicenter retrospective review of consecutive EVD procedures. Patients 18 years or older who underwent EVD and had a routine postoperative computed tomography (CT) scan performed within 24 hours were included. EVD-related hemorrhage was defined as new intracranial hemorrhage immediately adjacent or within the ventricular catheter trajectory. The volume of hemorrhage and the position of the catheter tip were assessed. A review of patient-, disease-, and surgery-related factors including the ventricular catheter design utilized was conducted. The Bonferroni correction was applied to the alpha level of significance (0.05) for multivariable analysis. RESULTS: Nine hundred sixty-two patients underwent 1002 EVD performed by neurosurgeons in the operating theater. Sixteen percent (154) of patients were on aspirin before the procedure. Thirty-four percent (333) of patients had intracerebral hemorrhage, 25% (251) had aneurysmal subarachnoid hemorrhage and 16% (158) had traumatic brain injury. The mean duration from EVD to the first postoperative CT scan was 20 ± 4 h. EVD-related hematomas were detected after 81 procedures with a per-catheter risk of 8.1%. Mean hematoma volume was 1.2 ± 3.3 ml. Most were less than 1 ml (grade I, 79%, 64), 1 to 15 ml (grade II) in 20% (16) and a single clot larger than 15 ml (grade III, 1%) were detected. Clinically significant hemorrhage that resulted in catheter occlusion occurred in 1.7% (17) of procedures. Most catheters (62%, 625) were optimally placed, i.e., its tip being within the ipsilateral frontal horn or third ventricle. Three non-antibiotic-impregnated ventricular catheter designs were used with 55% (550) being the 2.2-mm Integra™ catheter, 14% (137) being the 2.8-mm Medtronic™ catheter, and 31% (315) being the 3.1-mm Codman™ catheter. Independent significant predictors for EVD-related hemorrhage were the preoperative prescription of aspirin (adjusted OR 1.94; 95% CI 1.10-3.44), catheter malposition (aOR 1.99; 95% CI 1.22-3.23), and use of the 2.8-mm Medtronic™ catheter (aOR 4.22; 95% CI 2.39-7.41). CONCLUSIONS: The per-catheter risk of hemorrhage was 8.1%, but the incidence of symptomatic hemorrhage was low. The only patient risk factor was aspirin intake. This is the first study to evaluate and establish an association between catheter malposition and catheter design with EVD-related hemorrhage.

Epidural multi-slitted microporous non-absorbable patch in decompressive craniectomy to facilitate cranioplasty: a preliminary study.

Developing a surgical plane between the temporalis muscle and the dura is the most technically challenging step when performing cranioplasty for post-decompressive craniectomy defects. The authors report a simple technique to demarcate this surgical plane by laying a multi-slitted, microporous polyesterurethane (MPU) patch during decompressive craniectomy. Specifically, they tried to avoid creating potential spaces around the patch, which is the inherent drawback of published anti-adhesive techniques. In 21 patients undergoing decompressive craniectomy, and in 11 of them subsequently undergoing cranioplasty, there was no wound related complications. During cranioplasty, no epidural fluid collection was found; the patch could be separated from the temporalis muscle and the dura with blunt dissection leaving the muscle intact. They conclude that their epidural MPU patch technique is a safe technique, and appears useful to facilitate cranioplasty by helping the surgeon in developing the surgical plane between the temporalis muscle and the dura during cranioplasty.

Moving the goalposts: A comparison of different definitions for primary external ventricular drain infection and its risk factors: A multi-center study of 2575 patients.

External ventricular drainage is the most common procedure performed in daily neurosurgical practice. One devastating complication is ventriculostomy-associated infection, but the establishment of evidence-based management guidelines has been hindered by the lack of an universal definition. There is also limited data with regard to the utility of comorbidity health indices and surgery-related factors in predicting infection. This study aims to compare the incidence of infection according to five commonly used definitions and to identify risk factors for this complication. 2575 patients from seven neurosurgical centers in Hong Kong underwent primary external ventricular drainage. The frequency of infection according to Gozal was 2.2% (n=57), 4.7% (Chi), 0.6% (Lozier), 0.8% (Lyke) and 2.8% (Scheithauer). The commonest pathogen was coagulase negative staphylococcus (39%) and 49% of all microbial isolates were multiple-drug resistant. The mean Charlson comorbidity index was 0.5±1.1. Using Gozal's definition as the primary endpoint, the index was not predictive of infection and no surgical risk factors were identified. The only significant risk factor was the performance of two or more additional neurosurgical procedures within 30days of catheterization (OR: 2.1, 95% CI 1.1-4.5). The rate of infection is relatively low, but considerable disparity exists depending on the definition used. Our data implies that patient factors, in particular the Charlson comorbidity index, and variations in surgical practice are less influential than the strict observance of infection control measures. The high incidence of antibiotic-resistant bacteria is concerning and the routine of exchange of catheters within 30days should be discouraged.

Overshunting-associated myelopathy: report of 2 cases.

The authors present 2 cases of cervical myelopathy produced by engorged vertebral veins due to overshunting. Overshunting-associated myelopathy is a rare complication of CSF shunting. Coexisting cervical degenerative disc disease may further increase the difficulty of diagnosing the condition. Neurosurgeons and others who routinely evaluate patients with intracranial shunts should be familiar with this rare but possible diagnosis.

Results of excision of cerebral radionecrosis: experience in patients treated with radiation therapy for nasopharyngeal carcinoma.

OBJECT: In theory, the purpose of the treatment of cerebral radionecrosis (CRN), a nonneoplastic condition, is to minimize loss of brain function by preventing the progression and reversing some of the processes of CRN. In a practical sense, factors for achieving this purpose may include the following: removal of a CRN lesion that is causing mass effect, control of brain edema, prevention of recurrence of CRN lesions, minimization of adverse effects from treatments, and achievement of reasonably long and good-quality survivals. Based on these practical issues, the authors performed a retrospective study to evaluate the results of excision for the treatment of CRN. METHODS: The authors retrospectively reviewed the results of excision of CRN lesions in a group of patients with temporal lobe CRN due to radiotherapy for nasopharyngeal carcinoma. Patients who had undergone surgery at the authors' institution between January 1998 and November 2008 were analyzed. Surgical results were evaluated by assessing postoperative resolution of brain edema, recurrence of temporal lobe CRN, surgery-related complications, and postoperative functional status and survival. RESULTS: Twenty-four patients were included (age range 39-69 years; in 23 patients nasopharyngeal carcinoma was in remission). All patients underwent craniotomy for excision of the contrast-enhancing region. The indications for operation were temporal lobe CRN lesions with a mass-occupying effect beyond the temporal lobe. There were 32 craniotomies in all (mean postoperative follow-up 40 months). It was found that brain edema resolved rapidly postoperatively. The recurrence and reoperation rates were 6.3 and 3.1%, respectively. There were no surgery-related deaths. The median survival was 72 months, and 67% of the patients had a Karnofsky Performance Scale score of > or = 70% at the time of their last follow-up. CONCLUSIONS: In a specific group of patients with CRN of the temporal lobe in whom the CRN lesions were causing a mass-occupying effect beyond the temporal lobe, excision of the contrast-enhancing region was safe and could achieve prompt resolution of brain edema and a low incidence of recurrence of CRN.