Posterior Fossa Surgery Research Articles

Outcomes and Complications of Posterior Fossa Surgery in Sitting Versus Park-Bench Positions.

Background/Objectives: Patient positioning during surgery can influence intra- and postoperative complications. Therefore, we assessed the impact of the sitting and park-bench positions on anesthetic parameters and complications in neurosurgical patients. Methods and Patients: For this retrospective study, 314 adults who underwent neurosurgical procedures for posterior fossa pathologies were divided into two groups: sitting (n = 231) and park-bench (n = 83). The following data were collected, monitored, recorded, and compared: age, sex, tumor type, surgical approach, cardiovascular and respiratory complications, and postoperative surgical complications. The association of hypotension with the position was further investigated through multivariate logistic regression models by adjusting for CO2 decrease, desaturation, and documented gas embolism. Results: The average age was significantly lower in the sitting group (55 years, interquartile range (IQR) = 43-63; female proportion = 59.74%) than in the park-bench group (62 years, IQR = 45-74; female proportion = 57.83%) (p < 0.001). Cerebellopontine angle tumors were detected in 37.23% of the patients who underwent an operation in the sitting position and in 7.26% who underwent an operation in the park-bench position (p < 0.001). Patients in the sitting position had significantly greater anesthetic complication (91.77% vs. 71.08%, p < 0.001), hypotension (61.9% vs. 16.87%), and >2 mmHg CO2 decrease (35.06% vs. 15.66%, p < 0.001) incidences. Hypoxemia and death occurred more frequently in the park-bench group (8.43% vs. 1.73% and 6.03% vs. 1.3%, respectively). Conclusions: Compared with the park-bench position, the sitting position was associated with a greater specific anesthetic complication incidence and lower postoperative mortality rate, indicating a need for careful risk-benefit assessment when selecting each individual patient's surgical position.

Symptomatic cerebral vasospasm after posterior fossa surgery in pediatric patients: single-center study and systematic literature review.

The most common cause of cerebral vasospasm is subarachnoid hemorrhage, less frequently it occurs after trauma, infection, and tumor resection. Vasospasm in children is rare and has not been systematically investigated in posterior fossa surgery. The authors undertook a single-center retrospective study of all the pediatric patients who underwent surgery on the posterior fossa and presented with postoperative symptomatic vasospasm in the period from January 2018 to February 2024. Subsequently, a systematic literature review in accordance with the PRISMA guidelines was performed in the PubMed and Scopus databases to identify the published papers on symptomatic vasospasm after posterior fossa surgery in children. Of the 178 patients who underwent surgery on the posterior fossa, only one patient was diagnosed with symptomatic diffuse vasospasm on postoperative day 21. The systematic literature review provided further 9 children. The underlying pathology comprised 8 intra-axial lesions with 4 medulloblastomas, 1 schwannoma in the medulla oblongata, 1 pilocytic astrocytoma, 1 primitive neuroectodermal tumor, and 1 arteriovenous malformation. The extra-axial lesions were 1 hypoglossal schwannoma and 1 oculomotor nerve schwannoma. Iatrogenic symptomatic vasospasm after posterior fossa surgery in children is a rare complication with an outcome ranging from complete recovery to the death of the patient. It is important for all staff involved in the care of patients undergoing surgery on the posterior fossa to be aware of this rare postoperative complication. The small number of patients affected does not allow a substantiated conclusion to be drawn about predictive risk factors.

Patient height and American Society of Anesthesiologists class as significant risk factors for posterior fossa surgery in the semisitting position.

To optimize surgical positioning for posterior fossa surgery (PFS) using the semisitting position (SSP) to avoid venous air embolism (VAE) and its possible life-threatening consequences, the authors evaluated their experiences with the SSP by analyzing a large cohort of PFS patients. A retrospective analysis of the charts of 202 consecutive PFS patients (median age 54 years, IQR 41-61 years; 121 females) with various tumor or vascular conditions who underwent surgery in an SSP between 2019 and 2022 was performed. Age, sex, weight, height, BMI, American Society of Anesthesiologists (ASA) class, histology, duration of surgery, and length of hospital stay were assessed. Transesophageal echocardiography was used pre- and intraoperatively to monitor for and assess the degree of VAE. Altogether, VAE occurred in 30 of 202 (14.9%) patients, with clinically relevant VAE occurring in 14 of 202 (7%) patients. The grades of VAE were I, III, and IV in 16 (8%), 4 (2%), and 10 (5%) patients, respectively. Patient height (p = 0.04), ASA class (p = 0.03), and ASA class ≤ II (p = 0.02) remained the only preoperative statistically significant risk factors for intraoperative VAE, with a median height of 178 cm (IQR 172-184 cm) in patients with clinically relevant VAE compared with 170 cm (IQR 164-176 cm) in those without VAE. In summary, the data demonstrate that SSP can be used safely for PFS when taking special care to optimize positioning in tall and lower-grade ASA patients intraoperatively.

The Role of Watertight Dural Closure in Supratentorial Craniotomy: A Systematic Review and Meta-Analysis.

The idea of watertight dural closure (WTDC) seems extremely obvious to avoid complications such as cerebrospinal fluid (CSF) leak and infection, especially in spinal and posterior fossa surgeries. Nonetheless, several studies have shown that leaving the dura open is not associated with an increased risk of complications. The aim of this systematic review and meta-analysis is to compare non-WTDC and WTDC in patients undergoing supratentorial craniotomy regarding the risk of postoperative complications. We searched PubMed, Web of Science, Embase, and Cochrane for randomized control trials and observational studies comparing non-WTDC with WTDC in patients undergoing supratentorial craniotomy. Outcomes of interest were CSF leak, overall infection, meningitis, and subgaleal fluid collection (SFC). Statistical analysis was performed using RStudio 2023.12.1 + 402. Heterogeneity was assessed using I2 statistics. Of 1541 potential articles, 7 met the inclusion criteria. The review comprised 3 randomized control trials, 1 prospective study, and 3 retrospective cohort studies. Among the 1619 patients, 766 (47.3%) and 853 (52.7%) patients were in the non-WTDC and WTDC groups, respectively. There was no significant difference in CSF leak between the non-WTDC and WTDC groups (risk ratio [RR] 1.61; 95% CI 0.68-3.77; P = .276; I2 = 0%). Furthermore, we did not find significant differences in overall infection (RR 1.62; 95% CI 0.95-2.76; P = .078; I2 = 4%), meningitis (RR 1.87; 95% CI 0.64-5.46; P = .251; I2 = 0%), and SFC (RR 1.53; 95% CI 0.64-3.65; P = .342; I2 = 52%) between the non-WTDC and WTDC groups. These findings suggest that non-WTDC is a safe method and is not associated with an increased risk of CSF leak, overall infection, meningitis, and SFC compared with WTDC.

The effect of SARS-CoV-2 on the incidence of post-operative venous sinus thrombosis following skull base procedures.

Sinus thrombosis is a common post-operative finding after posterior fossa surgery performed in the vicinity of the dural venous sinuses. The SARS-CoV-2 virus has been shown to confer an increased risk of venous thromboembolic events owing to eliciting a hyper-inflammatory and pro-thrombotic state. In this study, we examine the incidence of post-operative venous sinus thrombosis in patients undergoing peri-sigmoid posterior fossa surgery in the pre- and post-COVID era and investigate whether COVID infection confers an increased risk of sinus thrombosis. A retrospective review of a single institution case series of patients underwent peri-sigmoid surgery (retrosigmoid, translabyrinthine, or far lateral) approach. Relevant clinical variables were investigated that may confer an increased risk of sinus thrombosis. A total of 311 patients (178 in the pre-COVID era, and 133 operated on after the pandemic began in March 2020) are included in the study. The composite incidence of sinus thrombosis seen on post-operative imaging was 7.8%. The incidence of sinus thrombosis in the pre-COVID cohort was N = 12 patients (6.7%) versus N = 12 (9%) in the post-COVID cohort (p = 0.46). A history of COVID infection was not shown to confer an increased risk of post-operative sinus thrombosis (OR: 0.61; 95% CI: 0.08-4.79, p = 0.64). Only a small number of patients (N = 7, 2.3%) required either medical or surgical intervention for post-operative sinus thrombosis. The overall incidence of post-operative sinus thrombosis is similar in the pre- and post-COVID era. The findings of this study suggest that COVID infection is not associated with a higher risk of venous sinus thrombosis.

Safety and Preliminary Efficacy of Cervical Paraspinal Interfascial Plane Block for Postoperative Pain after Pediatric Chiari Decompression.

Surgery for lesions of the posterior fossa is associated with significant postoperative pain in pediatric patients related to extensive manipulation of the suboccipital musculature and bone. In this study, we assess the preliminary safety, effect on neuromonitoring, and analgesic efficacy of applying a cervical paraspinal interfascial plane block in pediatric patients undergoing posterior fossa surgery. In this prospective case series, we enrolled five patients aged 2-18 years undergoing surgery for symptomatic Chiari type I malformation. An ultrasound-guided cervical cervicis plane (CCeP) block was performed prior to the incision. A local anesthetic agent (bupivacaine) and a steroid adjuvant (dexamethasone) were injected into the fascial planes between the cervical semispinalis capitis and cervical semispinalis cervicis muscles at the level of the planned suboccipital decompression and C1 laminectomy. Motor-evoked and somatosensory-evoked potentials were monitored before and after the block. Patients were assessed for complications from the local injection in the intraoperative period and for pain in the postoperative period. No adverse events were noted intraoperatively, and there were no changes in neuromonitoring signals. Pain scores were low in the immediate postoperative period, and rescue medications were minimal. No complaints of incisional pain or need for narcotics were noted at the time of the 3-month postsurgical follow-up. In this study, we demonstrate the preliminary safety and analgesic efficacy of a novel application of a CCeP block to pediatric patients undergoing suboccipital surgery. Larger studies are needed to further validate the use of this block in children.

Clinical, Anatomical, and Histological Features of the Rhomboid Lip and Considerations for Surgery Using a Retrosigmoid Approach: A Retrospective Study

The rhomboid lip is a neural tissue encountered during cerebellopontine angle surgery, with differing shape and extent among individuals. This study aimed to investigate the variation of rhomboid lips during posterior fossa surgery. In this retrospective study, we examined posterior cranial fossa surgeries performed using a retrosigmoid approach. Rhomboid lips were classified according to thickness, extent, and appearance, with some subjected to histological analysis. T2-weighted magnetic resonance imaging (MRI) of rhomboid lips was conducted. Among 304 surgeries, rhomboid lips were observed in 75 patients who underwent schwannoma or meningioma resection, facial spasm-related neurovascular decompression, and other surgeries (37, 2, 32, and 4 patients, respectively). Rhomboid lips were categorized based on apparent thickness: thin membranous type, resembling an arachnoid membrane, and thick parenchymal type. Rhomboid lip extension was classified by position relative to the choroid plexus: non-extension, lateral extension, and jugular foramen (41, 22, and 12 patients, respectively). Veins were observed on the rhomboid lip surface in 37 cases. The rhomboid lip was visible in only one case (parenchymal jugular foramen type) on MRI. Histologically, the rhomboid lip comprised an ependymal cell layer, a glial layer, and connecting tissue. The glial layer thickness determined the rhomboid lip thickness, which was greater in the parenchymal type than in the membrane type. In 42 patients, the rhomboid lip was dissected, with no complications observed. Morphological classification of the rhomboid lip and understanding of its anatomical details contribute to safe surgical field development for neurosurgeons.

Falx cerebelli and its associated occipital venous sinus: an anatomical study.

This study presents the morphological variation of falx cerebelli, which helps to identify the possible variations in the presence of the occipital sinus in the posterior margin of the fold whose damage during midline incision of posterior cranial fossa surgeries may lead to internal hemorrhage. The study was conducted on 48 cranial cavities exploring the falx cerebelli. Variations in the number of folds, its proximal and distal attachments, and the drainage pattern of the occipital sinus were evaluated by histological processing of the upper 1/3rd section of the falx fold. The variation in the number of folds recorded are single folds in 87.5%, double folded in 8.3%, and multiple folds (five and seven folded) in 4.2% of the cases. The variation in the proximal and distal attachments in single falx folds showed three combinations: Ramified triangular in 66.7%, both ramified type in 12.5%, and both triangular type in 8.3% of the cases. Double and multiple folds showed ramified and triangular types of variation in their attachments. Histological findings showed the presence of occipital venous sinuses in most of the single falx fold. Two aberrant venous sinuses were seen in a double and five-folded falx cerebelli. This study records the variations in the morphology of falx cerebelli. The histological data of this study sheds light on the drainage pattern of venous sinuses in the area whose negligence during midline incisions of brain surgeries may increase the possibility of hemorrhage.

Pseudomeningocele Following Posterior Cranial Fossa Surgery Significantly Increases the Risk of Intracranial Infection: A 10-Year Retrospective Analysis.

Background: Posterior fossa craniotomy is commonly performed for various pathologies. However, intra-cranial infection following craniotomy causes morbidity. Pseudomeningocele is one of the main complications following posterior fossa operation. This study aimed to test the hypothesis that the risk of intra-cranial infection is increased in patients who undergo posterior fossa craniotomy with pseudomeningocele compared with those without pseudomeningocele. Methods: We retrospectively analyzed the data of patients undergoing posterior fossa craniotomy for the management of neurological pathologies at our institute from 2011 to 2020. A total of 308 craniotomies were included, and the primary outcome of interest was the occurrence of intra-cranial infection. Standard statistical methods were used to explore associations between several parameters, including pseudomeningocele, intra-cranial infection, and wound leak. Results: Of the 308 craniotomies, 41 (13.3%) developed intra-cranial infection and 59 (19.2%) involved pseudomeningocele. Of cases involving pseudomeningocele, 27 (45.8%) developed an intra-cranial infection compared with only 14 of 249 without pseudomeningocele (5.6%; p < 0.001). In the multi-variable analysis, pseudomeningocele was associated with intra-cranial infection (odds ratio [OR] 8.56; 95% confidence interval [CI] 3.145-23.299; p < 0.001) and wound leak (OR 91.339; 95% CI 10.437-799.364; p < 0.001). Conclusion: The findings indicate that patients undergoing posterior fossa craniotomy are at a greater risk of intra-cranial infection if there is pseudomeningocele after the operation.

Posterior Fossa Craniotomy: Retrospective Analysis of 85 Patients

Aim: Craniectomy procedures were traditionally performed in posterior fossa surgeries. However, craniotomy procedure has also been started to be performed routinely in recent years. In this study, we aimed to evaluate the patients who underwent posterior fossa craniotomy procedures. Methods: The records of 85 patients who underwent posterior fossa craniotomy for various pathologies between 2016-2021 were retrospectively reviewed. Results: The mean age of the patients was 36.1 (2-82 years interval). There were 43 female patients (50.5%) and 42 male patients (49.5%). The pathologies was tumoral in 63 patients and non-tumoral in 22 patients. The symptoms of the patients identified were headache (84.5%), cerebellar symptoms (68%), deterioration of consciousness (54%), nause (48%), cranial nerve dysfunction (34%) and hemiparesis (18.5%). At admission, hydrocephaly was present in 22 patients. Ventriculoperitoneal shunt was applied to 12 of these patients. The duramater of the 68 patients were closed with primary suturation while 17 patients underwent duraplasty with fascia graft. Craniotomy flaps were fixed with only silk in 75 patients and miniplates in 10 patients. Two of the patients had pseudomeningocele and 1 had cerebrospinal fluid leak from the wound. The mortality rate was 3.5%. The mean duration of hospitalization was 7.6 days (2-54 days interval). Conclusion: Posterior fossa craniotomy technique has recently become widespread and begun to replace traditional craniectomy technique. It was facilitated by using high-speed drill with the advancement in technology. Posterior fossa craniotomy is a prominent technique with the low complication rates and high patient comfort in the postoperative period.

EPEN-05. SURGERY FOR CHILDHOOD EPENDYMOMA: THE EPENDYMOMA MULTIDISCIPLINARY ADVISORY GROUP (EMAG) CLINICAL TRIAL EXPERIENCE

Abstract INTRODUCTION The National Ependymoma Multidisciplinary Advisory Group (EMAG) is the central review mechanism for the SIOP Ependymoma II clinical trial in the UK. EMAG is a multiprofessional group which meets weekly to support decision making. We report detailed surgical outcomes for children with confirmed intracranial ependymoma, discussed through EMAG between January 2020 and November 2022. METHODS Data was collected on resection status, surgical outcomes, reasons for not achieving Gross Total Resection (GTR), number of surgeries and adjuvant therapies. Data was analysed descriptively. RESULTS After first surgery, GTR or near total resection (NTR) rate was 69/105 (66%) rising to 83/105 (79%) following repeated surgeries. 17 patients underwent second-look surgery prior to further therapy, whilst 9 underwent second-look surgery after chemotherapy but before radiotherapy. Eight (17%) posterior fossa (PF) surgeries were not completed due to factors including patient instability and tumour attachments. Most post-operative problems were seen in PF tumours with 26/60 (43%) bulbar palsy, 13/60 (22%) focal weakness and 12/60 (20%) cerebellar mutism. Incomplete PF resections were associated with increased bulbar palsy risk (p=0.02, Chi-Square test). 73% of PF patients required hydrocephalus management with external ventricular drainage, endoscopic third ventriculostomy (ETV) or shunt. Longer term hydrocephalus management with ETV or shunt was required in 29% and was more common in those with subtotal resection (R3-RX, 8/16, 50%) compared to GTR or NTR (R0-R2, 9/43, 21%, p=0.03). 27/60 (45%) received post-op NG feeding and 2/60 (3%) needed tracheostomies. Second surgery was associated with lower complication rates. DISCUSSION Our National MDT approach supports collaborative surgical decision making without a need for centralisation of the surgery itself. There was no evidence of increased complication rates compared to historical trials despite a more aggressive surgical approach. We argue for continued centralisation of EPN evaluation to support optimal care for children with this devastating disease.

IMG-01. LONGITUDINAL SIGNAL CHANGES IN THE DENTATE AND INFERIOR OLIVARY NUCLEI IN PATIENTS WITH CEREBELLAR MUTISM SYNDROME

Abstract BACKGROUND Cerebellar mutism syndrome (CMS) is a complication of posterior fossa surgery with an acute impairment in speech, and long-term neurocognitive deficits. Lesion mapping studies suggest the cognitive symptoms are associated with dentatorubrolivary damage1. We hypothesize that CMS patients will demonstrate more longitudinal MRI signal abnormalities in the dentate and inferior olivary nuclei as compared to non-CMS patients. METHODS MRI brains on 40 pediatric medulloblastoma patients between 2013-2015 were retrospectively reviewed by a neuroradiologist blinded to the diagnosis at pre-operative and immediate, 6-month, 12 month and most recent post-operative time points. The dentate and inferior olivary nuclei were scored for restricted diffusion, T1 and T2 hypo-and hyperintensity. A linear regression with different scores on CMS status (YES vs NO) was applied, after adjusting for age. RESULTS In the dentate nuclei, there was significantly higher T2 hypointensity in the CMS group on immediate (difference is 0.4084, p=0.0467) and most recent (difference is 0.7190, p=0.0386) post-operative MRIs. The CMS group had significantly higher T1 hyperintensity on the 1-year (difference is 0.9254, p=0.0108) and most recent (difference is 1.3291, p&amp;lt;0.001) post-operative MRIs. In the inferior olivary nuclei, there was significantly higher T2 hyperintensity on the 6-month (difference is 0.71, p=0.0045) and 1-year (difference is 0.6356, p=0.0162) post-operative MRIs. CONCLUSION The immediate post-operative findings are suggestive of a hemorrhagic, rather than an ischemic process in the dentate nuclei. On long-term follow up, the signal changes in the dentate and the inferior olivary nuclei represent dystrophic mineralization and hypertrophic degeneration, due to inflammation and axonal degeneration within the dentatorubroolivary tract2

Enabling Navigation and Augmented Reality in the Sitting Position in Posterior Fossa Surgery Using Intraoperative Ultrasound.

Despite its broad use in cranial and spinal surgery, navigation support and microscope-based augmented reality (AR) have not yet found their way into posterior fossa surgery in the sitting position. While this position offers surgical benefits, navigation accuracy and thereof the use of navigation itself seems limited. Intraoperative ultrasound (iUS) can be applied at any time during surgery, delivering real-time images that can be used for accuracy verification and navigation updates. Within this study, its applicability in the sitting position was assessed. Data from 15 patients with lesions within the posterior fossa who underwent magnetic resonance imaging (MRI)-based navigation-supported surgery in the sitting position were retrospectively analyzed using the standard reference array and new rigid image-based MRI-iUS co-registration. The navigation accuracy was evaluated based on the spatial overlap of the outlined lesions and the distance between the corresponding landmarks in both data sets, respectively. Image-based co-registration significantly improved (p < 0.001) the spatial overlap of the outlined lesion (0.42 ± 0.30 vs. 0.65 ± 0.23) and significantly reduced (p < 0.001) the distance between the corresponding landmarks (8.69 ± 6.23 mm vs. 3.19 ± 2.73 mm), allowing for the sufficient use of navigation and AR support. Navigated iUS can therefore serve as an easy-to-use tool to enable navigation support for posterior fossa surgery in the sitting position.

Posterior Cranial Fossa Surgery with a 3 Dimensional Exoscope: A Single-Center Survey-Based Analysis and a Literature Review

The potential advantages of exoscopy have been discussed theoretically for a long time. Such a concept holds significance, especially in the specific setting of the posterior cranial fossa (PCF), characterized by complex anatomy and long and narrow surgical corridors with relatively extreme working angles. We aimed to: 1) analyze the institutional preliminary case-based data on the use of the Robotic 3D Exoscope AEOS Aesculap in three different PCF approaches: retrosigmoid (RSA), midline suboccipital (MSA), and supracerebellar infratentorial via feedbacks was collected using a 20-point questionnaire, and 2) perform a comprehensive review of the literature concerning the use of EX in PCF surgery. A total of 38 patients with neurosurgical pathologies underwent a neurosurgical procedure using the EX (Robotic 3D exoscope AEOS Aesculap) at our institution between January and March 2022. 21 surgeons were involved in the abovementioned PCF surgeries and answered the questionnaire. The main perceived advantages were in terms of ergonomics (67%), magnification (52%), and visualization of extreme angles. The main reported disadvantage was color vision (16, 76%), followed by manual mobility (24%). Concerning the review, the search of the literature yielded a total of 177 results. Upon full-text review, 17 articles were included, including 153 patients. In conclusion, our study provides a comprehensive evaluation of the advantages and challenges associated with using the exoscope in posterior fossa surgery, setting a precedent as the first to report on a questionnaire-based analysis of exoscope utilization in this specific domain.

Thoracic spinal cord injury after surgical removal of a ruptured cerebellar arteriovenous malformation in a patient in the Concorde position: illustrative case.

Thoracic spinal cord injury after posterior cranial fossa surgery in younger patients is a rare complication. There have been reports of this complication in tumor and spine fields but not in vascular surgery. A 22-year-old-man experienced cerebellar arteriovenous malformation rupture, and the malformation was surgically removed with the man in the Concorde position. After surgery, the man had severe paraplegia, and a thoracic spinal cord injury was diagnosed. In younger patients, cervical hyperflexion in the Concorde position can cause thoracic spinal cord injury even in surgery for cerebrovascular disease.

The Posterior Auricularis Muscle as Superficial Landmark for the Sigmoid Sinus and Transverse-Sigmoid Sinus Junction: An Anatomical Study

Neuronavigation systems coupled with previously reported external anatomical landmarks assist neurosurgeons during intracranial procedures. We aimed to verify whether the posterior auricularis muscle (PAM) could be used as an external landmark for identifying the sigmoid sinus (SS) and the transverse-sigmoid sinus junction (TSSJ) during posterior cranial fossa surgery. The PAM was dissected in 10 adult cadaveric heads, and after drilling the underlying bone, the relationships with the underlying SS and TSSJ were noted. The width and length of the PAM, and the distance between the muscle and reference points (asterion, mastoid tip, and midline), were measured. The PAM was identified in 18 sides (9 left, 9 right). The first 20 mm of the muscle length (mean 28.28 mm) consistently overlay the mastoid process anteriorly and the proximal half of the SS slightly posteriorly on all sides. The superior border was a mean of 2.22 mm inferior to the TSSJ, and, especially when the muscle length exceeded 20 mm, this border extended closer to the transverse sinus; it was usually found at a mean of 3.11 mm (range 0.0-13.80 mm) inferior to the distal third of the transverse sinus. Superficial landmarks give surgeons improved surgical access, avoiding overexposure of deep neuro-vascular structures and reducing brain retraction. On the basis of our cadaveric study, the PAM is a reliable and accurate direct landmark for identifying the SS and TSSJ. The PAM could potentially be used for guiding the retrosigmoid approach.

Duraplasty with autologous cervical fascia in pediatric posterior fossa tumor surgery: a single-center experience with 214 cases.

Posterior fossa surgeries for pediatric tumors pose challenges in achieving optimal dural repair and duraplasty is usually required. Autografts, allografts, xenografts, and synthetic substitutes can be used for duraplasty. Autologous cervical fascia can be a safe and reliable graft option for duraplasty after posterior fossa surgeries. This study aims to investigate the outcomes of duraplasty with autologous cervical fascial graft in children after posterior fossa surgery for pediatric brain tumors. Pediatric patients with posterior fossa tumor who underwent surgery between March 2001 and August 2022 were retrospectively reviewed. Data on demographics, preoperative symptoms, diagnosis, tumor characteristics, hydrocephalus history, and postoperative complications, including cerebrospinal fluid (CSF) leakage, pseudomeningocele, and meningitis were collected. Logistic regression analysis was performed to explore risk factors for postoperative complications. Patient cohort included 214 patients. Autologous cervical fascia was used in all patients for duraplasty. Mean age was 7.9 ± 5.3years. Fifty-seven patients (26.6%) had preoperative hydrocephalus and 14 patients (6.5%) received VPS or EVD perioperatively. Postoperative hydrocephalus was present in 31 patients (14.5%). Rates of CSF leak, pseudomeningocele, and meningitis were 4.2%, 2.8%, and 4.2% respectively. Logistic regression analysis revealed that postoperative EVD and VPS placement were the factors associated with postoperative complications. Autologous cervical fascia is a safe and reliable option for duraplasty with minimal risk of postoperative complications. The straightforward surgical technique and with no additional cost for harvesting the graft renders autologous cervical fascia a favorable alternative for resource-limited countries or surgical settings.

Evaluation of safety of fluoxetine for cerebellar mutism syndrome in children after posterior fossa surgery

BackgroundCerebellar mutism syndrome (CMS) occurs in 8–29 % of children undergoing posterior fossa tumor surgery. Its main symptoms are mutism and emotional lability. Although it is always transient, recovery time can be lengthy with long-term cognitive sequelae. There is no approved drug treatment for CMS, but some drugs are used in everyday medical practice. One of these is fluoxetine, which has been used for many years in our institution. The main objective of this study was to establish the safety profile of fluoxetine in this condition. Materials and methodsThe records of patients admitted to the pediatric intensive care unit after brain surgery at Angers University Hospital from 2010 to 2020 were reviewed. Children aged 2 years and older who underwent a posterior fossa tumor surgery and were diagnosed with CMS were included. Data on patient characteristics, prescription of fluoxetine treatment, side effects if any, and complete mutism duration were collected. ResultsAmong 246 patients admitted to the pediatric intensive care unit for brain surgery during the study period, 23 had CMS and eight were prescribed fluoxetine. No serious adverse event related to fluoxetine was reported. Complete mutism duration did not differ significantly between the fluoxetine group and the non-fluoxetine group(p = 0.22). However, the treatment was initiated after recovery from complete mutism in half of the treated patients. ConclusionThis study suggests a positive safety profile of fluoxetine used in postoperative CMS. It does not answer the question of whether the treatment is effective for this indication. A randomized controlled trial based on a syndrome severity scale should be conducted to provide a more reliable assessment of the efficacy and safety of fluoxetine.

The feasibility and technical aspects of trigemino-cervical reflex elicitation in humans under general anesthesia

ObjectiveTo analyze the feasibility, neurophysiological aspects, stimulation patterns, and topographic distribution of trigemino-cervical reflex (TCR) components in humans under general anesthesia. MethodsThis prospective observational study enrolled 20 participants who underwent posterior fossa surgery, surgical proceduresin thecraniovertebral junction,or spinal cord surgery. TCR responses were simultaneously recorded in the sternocleidomastoid (SCM) and trapezius muscles after electrical stimulation of the supraorbital and infraorbital nerves. TCR responses were recorded preoperatively and intraoperatively using single-pulse and multipulse (trains of 2–7 electrical stimuli) stimulation, respectively. Two stimulus duration patterns were evaluated: 0.2–0.5 ms and 0.5–1.0 ms. ResultsIntraoperatively, short- and long-latency TCR components were obtained in the SCM ipsilateral to the stimulation with variable recordability. Short-latency responses were the most commonly recorded components. A longer stimulus duration (0.5–1.0 ms) seems to favor the elicitation of TCR responses under general anesthesia. ConclusionsShort-latency components recorded in the SCM ipsilateral to the stimulation could be regularly elicited under general anesthesia when a larger stimulus duration (0.5–1.0 ms) was applied. SignificanceThis is the first study to demonstrate the elicitation of TCR components in humans under general anesthesia. This neurophysiological technique can potentially optimize intraoperative neurophysiological monitoring during brainstem surgery.

PEG hydrogel sealant versus fibrin glue in posterior fossa surgery: an economic comparison across five European countries.

Aim: Posterior cranial fossa (PCF) surgery is associated with complications, including cerebrospinal fluid (CSF) leakage. Dural sealants such as polyethylene glycol (PEG)-based hydrogels and fibrin glue can prevent CSF leaks, with evidence suggesting PEG hydrogels may outperform fibrin glue. However, the budget impact of using PEG hydrogels in PCF surgeries in Europe is unclear. Materials & methods: A decision tree was developed based on a previous US model, to assess the budget impact of switching from fibrin glue to PEG hydrogel in PCF surgery across five European countries. Input costs were derived from published sources for the financial year 2022/2023. Health outcomes, including CSF leaks, were considered. Results: The model predicted that using PEG hydrogel instead of fibrin glue in PCF surgery can lead to cost savings in five European countries. Cost savings per patient ranged from EUR 419 to EUR 1279, depending on the country. Sensitivity analysis showed that the incidence of CSF leaks and pseudomeningoceles had a substantial impact on the model's results. Conclusion: PEG hydrogels may be a cost-effective alternative to fibrin glue in PCF surgery. The model predicted that cost savings would be mainly driven by a reduction in the incidence of postoperative CSF leaks, resulting in reduced reliance on lumbar drains, reparative surgery and shortened hospital stays.