Comparison of outcomes following complex posterior fossa surgery performed in the sitting versus lateral position

Surgery of brainstem cavernous malformations: surgical nuances and outcomes of a monocentric series of 34 patients

BACKGROUND

Brainstem cavernous malformations (BCM) constitute one of the most controversial and challenging neurological pathologies: both natural course and surgical manipulation can lead to severe neurological symptoms by direct compression or following hemorrhage of this highly eloquent brain region.

METHODS

The vascular section of the prospectively collected neurosurgical database of our center (2011-2023) was retrospectively reviewed, seeking all patients operated on for a sporadic BCM. Clinical, radiological and surgical data, operative records and videos were analyzed by independent reviewers with the assistance of a dedicated neuropsychologist, blinded to the hospital course.

RESULTS

Thirty-four patients aged between 19 and 70 years were identified and considered for analyses, with different brainstem localizations. The clinical onset was hemorrhagic in almost all cases: the average mRS on admission was 2.47 (21 patients ≤ 2). Surgical treatment was performed on average 15.1 weeks after the last bleeding. At hospital discharge, the mean mRS was 3.26 (6 patients ≤ 2). After a mean follow-up of 56.59 weeks, 29 patients (85.3%) presented an improved or stable mRS compared to hospitalization and 5 had a slight worsening (14.7%).

CONCLUSION

Brainstem cavernoma is a rare entity with aggressive features due to the involved eloquence despite of the benign histology itself. Microsurgical resection should be tailored for each patient to the peculiar characteristics of the harbored lesion. Advanced planning techniques reduced morbidity; patients should be centralized in wide caseload hospitals with high specialization in neurovascular pathologies and should receive an appropriate counseling about natural history and risks of interventional treatment.

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

Anaesthetic Management of a Foramen Magnum Meningioma Resection Surgery: A Case Report

The foramen magnum meningioma (FMM) is one of the most threatening tumours among the meningiomas because of its specific location, clinical course, subtle onset, and relatively big dimensions at presentation. Tumour size may mandate careful airway management to avoid further brainstem compression. The surgical management of these complex tumours in the posterior fossa can be performed with the patient in several positions. A lot of surgeons believe the sitting position provides important advantages, yet this remains controversial. We report a successful approach to a large FMM resection surgery performed in the sitting position.

Analysis of Imaging Results for Semisitting Compared with Supine Positioning in the Retrosigmoid Approach for Resection of Cerebellopontine Angle Vestibular Schwannomas

OBJECTIVE

To compare the completeness of resection of vestibular schwannomas using three-dimensional segmented volumetric analysis of pre- and postoperative magnetic resonance imaging (MRI) of patients undergoing supine and semisitting positioning for the retrosigmoid approach.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary medical center.

PATIENTS

Patients with vestibular schwannomas undergoing surgical resection via the retrosigmoid approach.

INTERVENTIONS

Tumor resection via the retrosigmoid approach with different patient positioning: standard supine versus semisitting.

MAIN OUTCOME MEASURES

Preoperative versus postoperative three-dimensional segmented volumetric MRI analysis of vestibular schwannomas.

RESULTS

A total of 43 patients (15 supine and 28 semisitting) underwent retrosigmoid craniotomy for resection of vestibular schwannomas. For the conventional supine and semisitting positioning, mean preoperative tumor volumes were 12.65 and 8.73 cm 3 ( p = 0.15), respectively. Postoperative mean tumor volumes for the supine and semisitting positions were 2.09 and 0.48 cm 3 ( p = 0.13), respectively. There were 11 cases of postoperative sigmoid sinus thrombosis, 3 in the conventional supine group and 8 in the semisitting groups, and there were 6 cases of postoperative cerebrospinal fluid leaks, all in the semisitting group. The mean House-Brackmann scores for the supine and semisitting groups were 2.9 and 2.3, respectively. There was no statistically significant difference between groups in the rates of these or any other postoperative complications.

CONCLUSIONS

The semisitting position for the suboccipital retrosigmoid approach for vestibular schwannoma resection does not compromise the ability to adequately resect the tumor as seen by volumetric MRI results. Further studies are needed to establish the safety of this position compared with the traditional supine approach.

How to position the patient? A meta-analysis of positioning in vestibular schwannoma surgery via the retrosigmoid approach

Objective

Patient positioning is a matter of ongoing debate in the surgical treatment of vestibular schwannoma (VS). Main endpoints of this discussion are preservation of facial nerve functioning, extent of resection, and complications. In this meta-analysis, we aim to investigate the impact of patient positioning on VS surgery via the retrosigmoid approach.

Methods

We searched for eligible comparative trials on PubMed, Cochrane library, and Web of Science. Positioning groups were compared regarding facial nerve outcome, extent of resection, postoperative hydrocephalus, postoperative CSF leaks, perioperative venous air embolism, and perioperative mortality. Two groups of positions were defined, and the following positions were allocated to those groups: (1) Semi-sitting and Sitting-position; (2) Lateral position, supine position with extensive head rotation, lateral oblique (=Fukushima/Three-quarter prone), and park-bench position.

Results

From 374 full-text screenings, 7 studies met the criteria and were included in our meta-analysis comprising 1640 patients. Our results demonstrate a significantly better long-term (≥6 months) outcome of the facial nerve after VS surgery in the semi-sitting positioning (OR: 1.49, 95%CI: 1.03-2.15, p = 0.03). Positioning did not influence the extent of resection, rate of postoperative CSF leaks, and the presence of a postoperative hydrocephalus. Overall incidence of venous air embolisms was significantly associated with VS surgery in sitting positioning (OR: 6.77, 95% CI: 3.66-12.54, p < 0.00001). Perioperative mortality was equal among both positioning groups.

Conclusion

Semi-sitting positioning seems to be associated with an improved facial nerve outcome after VS surgery via the retrosigmoid approach. Venous air embolisms are significantly more often observed among VS patients who underwent surgery in the sitting position, but the perioperative mortality is equal in both positioning groups. Both positioning groups are a safe procedure. Multicentric prospective randomized trials are needed to evaluate the risk-benefit ratio of each positioning in VS surgery via the retrosigmoid approach.

Analysis of risk factors for venous air embolism in the semisitting position and its impact on outcome in a consecutive series of 740 patients

OBJECTIVE

Routine use of the semisitting position, which offers several advantages, remains a matter of debate. Venous air embolism (VAE) is a potentially serious complication associated with the semisitting position. In this study, the authors aimed to investigate the safety of the semisitting position by analyzing data over a 20-year period.

METHODS

The incidence of VAE and its perioperative management were analyzed retrospectively in a consecutive series of 740 patients who underwent surgery between 1996 and 2016. The occurrence of VAE was defined by detection of bubbles on transthoracic Doppler echocardiography (TTDE) or transesophageal echocardiography (TEE) studies, a decrease of end-tidal CO2 (ETCO2) by 4 mm Hg or more, and/or an unexplained drop in systolic arterial blood pressure (≥ 10 mm Hg). From 1996 until 2013 TTDE was used, and from 2013 on TEE was used. The possible risk factors for VAE and its impact on surgical performance were analyzed.

RESULTS

There were 404 women and 336 men with a mean age at surgery of 49 years (range 1-87 years). Surgery was performed for infratentorial lesions in 709 patients (95.8%), supratentorial lesions in 17 (2.3%), and cervical lesions in 14 (1.9%). The most frequent pathology was vestibular schwannoma. TEE had a higher sensitivity than TTDE. While TEE detected VAE in 40.5% of patients, TTDE had a detection rate of 11.8%. Overall, VAE was detected in 119 patients (16.1%) intraoperatively. In all of these patients, VAE was apparent on TTDE or TEE. Of those, 23 patients also had a decrease of ETCO2, 18 had a drop in blood pressure, and 23 had combined decreases in ETCO2 and blood pressure. VAE was detected in 24% of patients during craniotomy before opening the dura mater, in 67% during tumor resection, and in 9% during wound closure. No risk factors were identified for the occurrence of VAE. Two patients had serious complications due to VAE. Surgical performance in vestibular schwannoma surgery was not affected by the presence of VAE.

CONCLUSIONS

This study shows that the semisitting position is overall safe and that VAE can be managed effectively. Persistent morbidity is very rare. The authors suggest that the semisitting position should continue to have a place in the standard armamentarium of neurological surgery.

The effects of different surgical positions (semi-sitting and lateral position) on the surgical outcomes of large vestibular schwannoma: study protocol for a randomized controlled trial

Background

There is an ongoing discussion about the advantages and disadvantages of different surgical positions (semi-sitting and lateral position) for vestibular schwannoma surgery. Each position has its advantages, disadvantages, challenges, and risk profiles. The objectives of this study are to compare the effects of different surgical positions (semi-sitting and lateral position) on the outcomes of large vestibular schwannoma, primarily including effectiveness and safety.

Methods

In this single-centre, open, randomized controlled trial, we will recruit a total of 116 participants according to the inclusion and exclusion criteria who will be randomized to an experimental group or control group. Patients will undergo operations in semi-sitting and lateral positions. The primary endpoint will be the percentage of gross total resection. The secondary endpoints will include the facial nerve function, hearing preservation, surgical position placement time, time of operation (skin-to-skin surgical time), hospital stay, total hospitalization fee, and complications. The follow-up period will be at least 12 months, during which time patients will be evaluated both clinically and radiologically.

Discussion

This issue is still debated after 30 years since the first large comparative study was published in 1989, so the study will be useful. Therefore, more high-quality studies are required to compare clinical outcomes, complications, and other factors associated with these two positions.

Trial registration

Chinese Clinical Trial Registry ChiCTR1900027550. Registered on 17 November 2019

The semisitting position in pediatric neurosurgery: pearls and pitfalls of a 10-year experience

OBJECTIVE

The authors sought to investigate the pearls and pitfalls of using the semisitting position in pediatric neurosurgery, with special focus on related morbidity and surgical practicability.

METHODS

All pediatric cases at a single institution were evaluated retrospectively. Those patients who underwent procedures in the semisitting position between December 2010 and December 2020 were included in the final analysis. Results were compared with all children who underwent surgery in the prone position for posterior fossa lesions within the same time frame.

RESULTS

A total of 42 posterior fossa surgeries were performed in 38 children in the semisitting position between December 2010 and December 2020. The mean patient age at the time of surgery was 8.9 years (range 13 months-18 years). The data of 24 surgeries performed in the prone position in 22 children during the same time frame were analyzed in comparison. Three children (7.9%) were diagnosed with a persistent foramen ovale preoperatively. The surgery was completed in all cases. The incidence of venous air embolism (VAE) was 11.9%. There was no VAE-related hemodynamic instability, infarction, or death. Endoscopic techniques were applied safely in 14 cases (33.3%). Postoperative pneumocephalus occurred significantly more frequently in patients who had undergone procedures in the semisitting position (p < 0.05), but without the need for intervention. During 1 surgery (2.4%), the patient experienced a postoperative skull fracture and epidural bleeding due to the skull clamp application. Clinical status of the patients immediately after surgery was improved or stable in 33 of the 42 surgeries (78.6%) performed in the semisitting position.

CONCLUSIONS

With attentive performance and an experienced surgical team, the semisitting position is a safe option for posterior fossa surgery in the pediatric population. With a comparable complication profile, the semisitting position offers excellent anatomical exposure, which is ideal for the application of endoscopic visualization. Careful skull clamp application and appropriate monitoring are highly recommended.

Outcomes after semisitting and lateral positioning in large vestibular schwannoma surgery: A single-center comparison

OBJECTIVE

The semisitting position (SSP) and lateral position (LP) in vestibular schwannoma (VS) surgery each have advantages and disadvantages, and which position is superior overall is debatable. Our objective was to determine the optimal position for surgical treatment of VSs with a diameter ≥3 cm.

METHODS

We retrospectively evaluated consecutive patients with a large VS treated between January 2010 and July 2020. Patients were grouped by surgical position and analyzed.

RESULTS

We enrolled 259 patients (LP group, n = 156; SSP group, n = 103). The resection extent was not significantly different between the SSP (gross-total resection [GTR], n = 89 [88.1%], near-total resection [NTR], n = 10 [9.9%], subtotal resection [STR], n = 2 [2.0%]) and LP (GTR, n = 125 [80.1%]; NTR, n = 24 [15.4%]; STR, n = 7 [4.5%]) groups. The rate of GTR with facial nerve (FN) functional preservation was higher in the SSP group than in the LP group (P = 0.014) at eight days after the operation. However, during follow-up (SSP group median, 31.5 months; LP group median, 19.5 months), there was no significant between-group difference in FN functional preservation. Two patients in the SSP group required conversion to the LP due to severe intraoperative venous air embolism (VAE).

CONCLUSION

Compared with the LP, the SSP did not produce significantly better FN outcomes in patients with a large VS. The duration of surgery was significantly longer in SSP cases than in LP cases. Given the risk of VAE associated with the SSP, the selection of the optimal surgical position should be made with caution on an individual basis.

EANO guideline on the diagnosis and treatment of vestibular schwannoma

The level of evidence to provide treatment recommendations for vestibular schwannoma is low compared with other intracranial neoplasms. Therefore, the vestibular schwannoma task force of the European Association of Neuro-Oncology assessed the data available in the literature and composed a set of recommendations for health care professionals. The radiological diagnosis of vestibular schwannoma is made by magnetic resonance imaging. Histological verification of the diagnosis is not always required. Current treatment options include observation, surgical resection, fractionated radiotherapy, and radiosurgery. The choice of treatment depends on clinical presentation, tumor size, and expertise of the treating center. In small tumors, observation has to be weighed against radiosurgery, in large tumors surgical decompression is mandatory, potentially followed by fractionated radiotherapy or radiosurgery. Except for bevacizumab in neurofibromatosis type 2, there is no role for pharmacotherapy.

Medulloblastoma in adults - reviewing the literature from a surgeon's point of view

Medulloblastoma is a common primary brain tumor in children but it is a rare cancer in adult patients. We reviewed the literature, searching PubMed for articles on this rare tumor entity, with a focus on tumor biology, advanced neurosurgical opportunities for safe tumor resection, and multimodal treatment options. Adult medulloblastoma occurs at a rate of 0.6 per one million people per year. There is a slight disparity between male and female patients, and patients with a fair skin tone are more likely to have a medulloblastoma. Patients present with cerebellar signs and signs of elevated intracranial pressure. Diagnostic efforts should consist of cerebral MRI and MRI of the spinal axis. Cerebrospinal fluid should be investigated to look for tumor dissemination. Medulloblastoma tumors can be classified as classic, desmoplastic, anaplastic, and large cell, according to the WHO tumor classification. Molecular subgroups include WNT, SHH, group 3, and group 4 tumors. Further molecular analyses suggest that there are several subgroups within the four existing subgroups, with significant differences in patient age, frequency of metastatic spread, and patient survival. As molecular markers have started to play an increasing role in determining treatment strategies and prognosis, their importance has increased rapidly. Treatment options include microsurgical tumor resection and radiotherapy and, in addition, chemotherapy that respects the tumor biology of individual patients offers targeted therapeutic approaches. For neurosurgeons, intraoperative imaging and tumor fluorescence may improve resection rates. Disseminated disease, residual tumor after surgery, lower radiation dose, and low Karnofsky performance status are all suggestive of a poor outcome. Extraneural spread occurs only in very few cases. The reported 5-year-survival rates range between 60% and 80% for all adult medulloblastoma patients.

Anesthetic Management of Patients Undergoing Open Suboccipital Surgery

The posterior cranial fossa with its complex anatomy houses key pathways regulating consciousness, autonomic functions, motor and sensory pathways, and cerebellar centers regulating balance and gait. The most common posterior fossa pathologies for which neurosurgical intervention may be necessary include cerebellopontine angle tumors, aneurysms, and metastatic lesions. The posterior cranial fossa can be accessed from variations of the supine, lateral, park-bench, prone, and sitting positions. Notable complications from positioning include venous air embolism, paradoxic air embolism, tension pneumocephalus, nerve injuries, quadriplegia, and macroglossia. An interdisciplinary approach with careful planning, discussion, and clinical management contributes to improved outcomes and reduced complications.

Extreme Lateral Supracerebellar Infratentorial Approach: Surgical Anatomy and Review of the Literature

OBJECTIVE

The extreme lateral supracerebellar infratentorial (ELSI) approach has the potential to access several distinct anatomical regions that are otherwise difficult to reach. We have illustrated the surgical anatomy through cadaveric dissections and provided an extensive review of the literature to highlight the versatility of this approach, its limits, and comparisons with alternative approaches.

METHODS

The surgical anatomy of the ELSI has been described using 1 adult-injected cadaveric head. Formalized noninjected brain specimens were also dissected to describe the brain parenchymal anatomy of the region. An extensive review of the literature was performed according to each targeted anatomical region. Illustrative cases are also presented.

RESULTS

The ELSI approach allows for wide exposure of the middle and posterolateral incisural spaces with direct access to centrally located intra-axial structures such as the splenium, pulvinar, brainstem, and mesial temporal lobe. In addition, for skull base extra-axial tumors such as petroclival meningiomas, the ELSI approach represents a rapid and adequate method of access without the use of extensive skull base approaches.

CONCLUSIONS

The ELSI approach represents one of the most versatile approaches with respect to its ability to address several anatomical regions centered at the posterior and middle incisural spaces. For intra-axial pathologies, the approach allows for access to the central core of the brain with several advantages compared with alternate approaches that frequently involve significant brain retraction and cortical incisions. In specific cases of skull base lesions, the ELSI approach is an elegant alternative to traditionally used skull base approaches, thereby avoiding approach-related morbidity.

Vestibular Schwannoma Surgery: Outcome and Complications in Lateral Decubitus Position versus Semi-sitting Position-A Personal Learning Curve in a Series of 544 Cases over 3 Decades

OBJECTIVE

To retrospectively evaluate influence of intraoperative positioning (semisitting vs. lateral decubitus) and surgeon's learning curve with regard to functional outcome of patients with vestibular schwannoma.

METHODS

This study included 544 patients (median age 57 years) and spanned 3 decades: 1991-1999 (n = 103), 2000-2009 (n = 210), and 2010-2019 (n = 231). Surgery was performed in the lateral decubitus position in 318 patients and the semisitting position in 163 patients. Large T3 and T4 tumors were present in 77% of patients.

RESULTS

Complete tumor removal was achieved in 94.3% of patients. A significant reduction in surgery duration and blood loss was observed over 3 decades for T3 (from 325 to 261 minutes, P < 0.001) and T4 (from 440 to 330 minutes, P < 0.001), but not for T1 and T2, tumors. The semisitting position diminished surgical time in T3 and T4 tumors by 1 more hour (P < 0.001). Over 3 decades, facial nerve outcome improved significantly from 59.8% House-Brackmann grade 1-2 in the first decade to 81.7% in the last decade (P < 0.001). Furthermore, hearing was preserved in 45.3%: 23.3% of patients in the first decade and 50.5% in the last decade (P = 0.03). However, neither facial nerve outcome nor hearing preservation significantly differed in patients operated on in the lateral decubitus versus the semisitting position. The most common complication was cerebrospinal fluid leak (6.1%) followed by hemorrhage (3.5%) and pulmonary embolism (2.2%).

CONCLUSIONS

Follow-up over 3 decades illustrates a learning curve with significantly improved results. While the semisitting position accelerates the procedure and is associated with reduced blood loss, it does not significantly influence functional outcome.

Estimation of the head elevation angle that causes clinically important venous air embolism in a semi-sitting position for neurosurgery: a retrospective observational study

Introduction:

The benefits of a sitting position for neurosurgery involving the posterior fossa remain controversial. The main concern is the risk of venous air embolism (VAE). A recent study showed that the rate of VAE was higher when the head was elevated to 45° than when it was elevated to 30°. However, the degree of head elevation that causes clinically important VAE is unclear. The purpose of this study was to estimate the head elevation angle at which the probability of VAE is 50% by using EtCO₂ monitoring to detect of VAE.

Methods:

The anesthesia records of 23 patients who underwent neurosurgery in a sitting position were reviewed retrospectively. Intraoperative ventilation was set to maintain EtCO₂ at approximately 38-42 mmHg. The head elevation angle in each case was determined from a photograph taken by the anesthesiologist or brain surgeon. Nineteen of the 23 cases had photographs available that contained a horizontal reference in the background. Seven cases were treated as VAE during the operation. Six of these cases met the criteria for VAE in this study. Data analysis was performed on a total of 18 patients. The angle between the line connecting the hip joint and the shoulder joint and the horizontal reference was obtained by ImageJ software. Logistic regression was performed using the Python programming language to determine the head elevation angle at which the probability of air embolism was 50%.

Results:

The decision boundary in the logistic regression was 35.7°. This head elevation angle was the boundary where the probability of VAE was 50%.

Conclusion:

The angle of head elevation that caused clinically important VAE was estimated to be 35.7°.

A critical comparison between the semisitting and the supine positioning in vestibular schwannoma surgery: subgroup analysis of a randomized, multicenter trial

OBJECTIVE

Patient positioning in vestibular schwannoma (VS) surgery is a matter of ongoing discussion. Factors to consider include preservation of cranial nerve functions, extent of tumor resection, and complications. The objective of this study was to determine the optimal patient positioning in VS surgery.

METHODS

A subgroup analysis of a randomized, multicenter trial that investigated the efficacy of prophylactic nimodipine in VS surgery was performed to investigate the impact of positioning (semisitting or supine) on extent of resection, functional outcomes, and complications. The data of 97 patients were collected prospectively. All procedures were performed via a retrosigmoid approach. The semisitting position was chosen in 56 patients, whereas 41 patients were treated while supine.

RESULTS

Complete resection was obtained at a higher percentage in the semisitting as compared to the supine position (93% vs 73%, p = 0.002). Logistic regression analysis revealed significantly better facial nerve function in the early postoperative course in the semisitting group (p = 0.004), particularly concerning severe facial nerve paresis (House-Brackmann grade IV or worse; p = 0.002). One year after surgery, facial nerve function recovered. However, there was still a tendency for better facial nerve function in the semisitting group (p = 0.091). There were no significant differences between groups regarding hearing preservation rates. Venous air embolism with the necessity to terminate surgery occurred in 2 patients in the semisitting position (3.6%). Supplementary analysis with a 2-tailed permutation randomization with 10,000 permutations of treatment choice and a propensity score matching showed either a tendency or significant results for better facial nerve outcomes in the early postoperative course and extent of resection in the semisitting group.

CONCLUSIONS

Although the results of the various statistical analyses are not uniform, the data indicate better results concerning both a higher rate of complete removal (according to the intraoperative impression of the surgeon) and facial nerve function after a semisitting as compared to the supine position. These advantages may justify the potential higher risk for severe complications of the semisitting position in VS surgery. The choice of positioning has to consider all individual patient parameters and risks carefully.

The Effects of Patient Positioning on the Outcome During Posterior Cranial Fossa and Pineal Region Surgery

Background: Surgery on posterior cranial fossa (PCF) and pineal region (PR) carries the risks of intraoperative trauma to the brainstem structures, blood loss, venous air embolism (VAE), cardiovascular instability, and other complications. Success in surgery, among other factors, depends on selecting the optimal patient position. Our objective was to find associations between patient positioning, incidence of intraoperative complications, neurological recovery, and the extent of surgery.

Methods: This observational study was conducted in two medical centers: The Ohio State University Wexner Medical Center (USA) and The Burdenko Neurosurgical Institute (Russian Federation). Patients were distributed in two groups based on the surgical position: sitting position (SP) or horizontal position (HP). The inclusion criteria were adult patients with space-occupying or vascular lesions requiring an open PCF or PR surgery. Perioperative variables were recorded and summarized using descriptive statistics. The post-treatment survival, functional outcome, and patient satisfaction were assessed at 3 months.

Results: A total of 109 patients were included in the study: 53 in SP and 56 in HP. A higher proportion of patients in the HP patients had >300 mL intraoperative blood loss compared to the SP group (32 vs. 13%; p = 0.0250). Intraoperative VAE was diagnosed in 40% of SP patients vs. 0% in the HP group (p < 0.0001). However, trans-esophageal echocardiographic (TEE) monitoring was more common in the SP group. Intraoperative hypotension was documented in 28% of SP patients compared to 9% in HP group (p = 0.0126). A higher proportion of SP patients experienced a new neurological symptom compared to the HP group (49 vs. 29%; p = 0.0281). The extent of tumor resection, postoperative 3-months survival, functional outcome, and patient satisfaction were not different in the groups.

Conclusions: The SP was associated with, less intraoperative bleeding, increased intraoperative hypotension, VAE, and postoperative neurological deficit. More HP patients experienced macroglossia and increased blood loss. At 3 months, there was no difference of parameters between the two groups.

Clinical Trial Registration:ClinicalTrials.gov: registration number NCT03364283.

Facial nerve function and hearing after microsurgical removal of sporadic vestibular schwannomas in a population-based cohort

BACKGROUND

Vestibular schwannoma (VS) is a benign tumor originating from the vestibulocochlear nerve. The optimal treatment strategy is debated, since surgery may result in iatrogenic facial nerve injury. We report the results of VS surgery in a population-based unselected cohort in a center with access to Cyber Knife (CK) radiosurgery.

METHODS

We reviewed 117 consecutive operations and found 95 patients who had their primary operation due to vestibular schwannoma between 2001 and 2017. Facial nerve function was evaluated with the House-Brackmann (HB) scale and hearing with the EU classification.

RESULTS

The population consisted of 37 males and 58 females with a median age of 54 years (range 19-79). One year after surgery 67% of patients had a good outcome (HB 1-2). The rate of good outcome was 90% if no facial nerve damage was observed during intraoperative monitoring, the size of the tumor was under 30 mm and no hydrocephalus was present. During the study period, the treatment strategy changed from total to near-total resection after the introduction of CK radiosurgery, which could be used as a second-line treatment in case of residual tumor regrowth. This resulted in an improvement of outcomes (0% HB 5-6) despite the larger tumor sizes (25 ± 14 mm vs. 31 ± 9 mm, p < 0.05). Hearing preservation rates did not increase.

CONCLUSIONS

Near-total resection and subsequent CK radiosurgery in case of residual tumor regrowth during follow-up seems to provide a good outcome of facial nerve function even in large VSs.

Extreme lateral supracerebellar infratentorial approach: how I do it

BACKGROUND

The extreme lateral supracerebellar infratentorial (ELSI) approach was initially proposed to treat lesions of the posterolateral surface of the pons principally cavernomas. The versatility of the approach allowed its use for other pathologies like gliomas, aneurysms, epidermoids, and meningiomas.

METHOD

We describe here the ELSI approach along with its advantages and limits in comparison with other surgical approaches for the treatment of meningiomas of the petroclival region.

CONCLUSION

ELSI is a versatile approach that allows access to the anterolateral brainstem surface including extensions to the midbrain diencephalic junction when needed. ELSI compares favorably to other surgical alternatives with respect to the approach-related morbidity, while allowing adequate access to treat the pathology.

Cerebellar Mutism Syndrome and Other Complications After Surgery in the Posterior Fossa in Adults: A Prospective Study

BACKGROUND

Cerebellar mutism syndrome (CMS) is rarely described in adults; however, data on self-assessed linguistic complications after posterior fossa surgery do not exist.

METHODS

Through a prospective single-center study, data on 59 tumor operations in the posterior fossa were collected preoperatively as well as 1 week and 1 month postoperatively. Data on self-assessed problems in 5 CMS-related domains, CMS scores, and neurology as well as surgical procedure and complications were obtained.

RESULTS

Data on CMS-related complications were obtained on 56 of the 59 operations. None was found to have CMS according to the CMS score. Within each of the 5 domains, at least 9 operations (16%) were followed by development or worsening of self-assessed CMS-related complications. Self-assessed complications were found to be most frequent after primary tumor surgeries, although they were significant only for speech and motor complications (P value = 0.01 and 0.02). Speech and language complications occurred more frequently in midline tumors compared with lateral tumors (40% vs. 7%; P = 0.004). Surgical complications were similar to other studies.

CONCLUSIONS

We propose that speech and language problems in adults undergoing surgery in the posterior fossa occur more frequently than previously assumed. Some of the self-assessed complications might reflect components of the cerebellar cognitive affective syndrome. Our findings are consistent with the fact that midline location of the tumor is one of the few known risk factors for CMS in children. Thus, the cerebellar midline seems to be a vulnerable region for speech and language complications also in adults.

A systematic review about the position-related complications of acoustic neuroma surgery via suboccipital retrosigmoid approach: Sitting versus lateral

This systematic review wasdesigned to compare the complications of acoustic neuroma surgery via the suboccipital retrosigmoid approach in the sitting versus lateral positions. Searches for randomized trials and observational studies about the complications of acoustic neuroma surgery were performed in five medical databases (though October 2015) including PubMed, MEDLINE (In-Process and Other Non-Indexed Citations), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and PsycINFO. Primary outcomes in this study were venous air emboli, neuropsychological defects, CSF leak, facial and abducens nerves palsy, postoperative deafness, hydrocephalus and mortality. Secondary outcomes were total tumor removal, facial and cochlear nerves preservation and ataxia. 843 abstracts and titles were reviewed and 10 studies (two non-randomized comparative studies and 8 non-comparative case series) were included for data extraction. Because of the heterogeneity of the studies, small number of participants and methodological shortcomings, findings were evaluated qualitatively. No impressive advantage was found in surgical or neurological outcomes for use of the sitting or lateral positions in patients with acoustic neuroma surgery. According to the available evidence, it seems that both sitting and lateral positions can be used with an equivalent safety for acoustic neuroma surgery via the retrosigmoid suboccipital approach. There seems a clear need for comparative studies to compare harms and other outcomes for these two positions.

Improved Postoperative Facial Nerve and Hearing Function in Retrosigmoid Vestibular Schwannoma Surgery Significantly Associated with Semisitting Position

OBJECTIVE

The pros and cons of semisitting positioning (SSP) versus lateral, horizontal positioning (LP) during retrosigmoid vestibular schwannoma (VS) surgery, especially concerning postoperative cranial nerve and brain stem preservation, are under continuous discussion.

METHODS

In a single-center retrospective cohort study, 30 VSs operated on in SSP compared with 30 operated on in LP with comparable demography were analyzed. During SSP surgery, transesophageal echocardiographic monitoring for venous air embolism was used continuously. Electrophysiologic cranial nerve monitoring was used in both groups.

RESULTS

Length of surgery was significantly different between both groups: 183 minutes mean in SSP surgery versus 365 minutes mean in LP surgery (P = 0.0001). Postoperative rates of facial palsy and hearing loss were also significantly different. Six months postoperatively, 63% had normal facial nerve function after SSP surgery, whereas in LP surgery, 40% had no facial palsy (P = 0.02). Hearing preservation rate was also significantly different: 44% in SSP surgery compared with 14% in LP surgery who had preserved hearing (P = 0.006). Because of cerebrospinal fluid leaks, there were 3 operative revisions in the LP group (10%) and 1 (3.3%) in the SSP group. A clinically insignificant venous air embolism rate was found in 3.3% of patients (1/30) during SSP surgery. The neurologic outcome after 6 months was 1.2 on the Rankin Scale in the LP group and 1.0 in the SSP group, with zero mortality.

CONCLUSIONS

SSP compared with LP surgery was associated with significantly shorter operation time and better facial and cochlear nerve function in VS surgery postoperatively, without differences in complication rates.