Intracranial Epidermoid Cyst: A Volumetric Study of a Surgically Challenging Benign Lesion.

BACKGROUND: Intracranial epidermoid cysts are rare, benign tumors. Nevertheless, the microsurgical removal of these cysts is challenging. This is due to their capacity to adhere to the neurovascular tissue, as well as the associated difficulties in microsurgically peeling off their capsular wall hidden in dead angles. To better understand the rate of recurrence after surgical intervention, we have performed preoperative and postoperative volumetric analysis of epidermoid cysts, allowing the estimation of their growth rate after resection. METHODS: Imaging data from 22 patients diagnosed and surgically treated for an intracranial epidermoid cyst between 2000 and 2022 were retrospectively collected from 2 European neurosurgical centers with microsurgical expertise. Volumetric analysis was performed on magnetic resonance imaging data. RESULTS: Average cyst volume at diagnosis, before any surgery, measured in 12 patients was 28,877.6 ± 10,250.4 mm3 (standard error of the mean [SEM]). Estimated growth rate of incompletely resected epidermoids after surgery was 1,630.05 mm3 ± 729.95 (SEM). Assuming linear growth dynamics and normalizing to postoperative residual volume, the average postoperative growth rate corresponded to 61.5% ± 34.3% (SEM) of the postoperative residual volume per year. We observed signs of recurrence during a radiologic follow-up period of 6.0 ± 2.8 years (standard deviation) in more than 50% of our patients. CONCLUSIONS: Due to their slow-growing nature, epidermoid cysts can often reach a complex multicompartmental size before resection, even in young patients, thus requiring complex approaches with challenging capsular resection, which implies a high risk of nerve and vascular injury per se. Tumor recurrence may be predicted on the basis of postoperative volumetry.

Neurosurgery elucidates somatic mutations.

Surgical innovation is helping to identify roles for somatic mutations in brain disorders.

How I do it: simplified craniotomy for acute subdural hematoma in the elderly.

CONTEXT: Acute subdural hematoma (ASH) is responsible for significant morbidity and mortality in the elderly. As military neurosurgeons, we perform a simplified technique using a linear skin incision and a small craniotomy bone flap in order to ease perioperative tolerance. METHODS: The patient lies supine, a pad under the shoulder ipsilateral to the ASH, the head completely rotated on the other side and placed on a circular pad, without head clamp. The linear frontotemporal skin incision should be twice the size of the bone flap's diameter, allowing to access the whole subdural space. Care is taken to obtain complete decompression of the temporal fossa in order to alleviate uncal herniation. A subdural drain can be placed, and the subdural space is filled with warm saline solution in order to create a closed drainage system. CONCLUSION: The patient is allowed to sit at postoperative day 1 and to walk at postoperative day 2. Simplified craniotomy for ASH allows to reduce operative time and provides faster functional recovery.

Endoscopic odontoidectomy for brainstem compression in association with posterior fossa decompression and occipitocervical fusion.

OBJECTIVE: Endonasal endoscopic odontoidectomy (EEO) is an alternative to transoral surgery for symptomatic ventral compression of the anterior cervicomedullary junction (CMJ), allowing for earlier extubation and feeding. Because the procedure destabilizes the C1-2 ligamentous complex, posterior cervical fusion is often performed concomitantly. The authors' institutional experience was reviewed to describe the indications, outcomes, and complications in a large series of EEO surgical procedures in which EEO was combined with posterior decompression and fusion. METHODS: A consecutive, prospective series of patients who underwent EEO between 2011 and 2021 was studied. Demographic and outcome metrics, radiographic parameters, extent of ventral compression, extent of dens removal, and increase in CSF space ventral to the brainstem were measured on the preoperative and postoperative scans (first and most recent scans). RESULTS: Forty-two patients (26.2% pediatric) underwent EEO: 78.6% had basilar invagination, and 76.2% had Chiari type I malformation. The mean ± SD age was 33.6 ± 3.0 years, with a mean follow-up of 32.3 ± 4.0 months. The majority of patients (95.2%) underwent posterior decompression and fusion immediately before EEO. Two patients underwent prior fusion. There were 7 intraoperative CSF leaks but no postoperative CSF leaks. The inferior limit of decompression fell between the nasoaxial and rhinopalatine lines. The mean ± SD vertical height of dens resection was 11.98 ± 0.45 mm, equivalent to a mean ± SD resection of 74.18% ± 2.56%. The mean increase in ventral CSF space immediately postoperatively was 1.68 ± 0.17 mm (p < 0.0001), which increased to 2.75 ± 0.23 mm (p < 0.0001) at the most recent follow-up (p < 0.0001). The median (range) length of stay was 5 (2-33) days. The median time to extubation was 0 (0-3) days. The median time to oral feeding (defined as, at minimum, toleration of a clear liquid diet) was 1 (0-3) day. Symptoms improved in 97.6% of patients. Complications were rare and mostly associated with the cervical fusion portion of the combined surgical procedures. CONCLUSIONS: EEO is safe and effective for achieving anterior CMJ decompression and is often accompanied by posterior cervical stabilization. Ventral decompression improves over time. EEO should be considered for patients with appropriate indications.

Microsurgical Clipping of Complex Basilar Bifurcation Aneurysms through Different Approachs: Surgical Techniques and Results.

AIM: To explore the surgical approach, technique and clinical effect of treating basilar bifurcation aneurysms. MATERIAL AND METHODS: The clinical data of basilar bifurcation aneurysms treated by neuro-microsurgery are retrospectively analyzed in from September 2013 to September 2018. The aneurysms were treated via subtemporal approach and frontotemporal approach. The results were evaluated according to Glasgow Outcome Scores (GOS) and postoperative imaging results. RESULTS: There were 28 aneurysms located at the bifurcation of basilar artery in 27 patients and 1 case had multi-aneurysms. 8 cases underwent via subtemporal approach and 19 via frontotemporal approach. The operation time was 2.8-4.6 hours, the average time were 3.3 hours. The hospitalization time was 3-6 weeks, the average time was 3.8 weeks. Overall, good outcome (GOS score of 4-5) at 6 months was achieved in 77.8% of the living patients. The posterior thalamic perforator artery infarction occurred in 1 cases, and the ventriculoperitoneal shunting was performed in 2 cases due to communicating hydrocephalus. During the following-up period, 25 patients underwent head CTA examination. The CTA showed that all aneurysms were completely clipped, no aneurysm recurrence was found, the blood flow of the parent artery was unobstructed, and 2 patients were lost to follow-up. 13 patients had oculomotor nerve palsy, and all but 3 of them recovered during following-up. CONCLUSION: The satisfactory results were achieved by microsurgical clipping for basilar bifurcation aneurysms. According to the location and projection of aneurysms, personalized treatment is chosen. Trans-frontotemporal approach is the most suitable approach for the treatment of upper basilar bifurcation aneurysms, especially under subarachnoid hemorrhage causing brain swelling conditions.

Hyperammonaemic encephalopathy following bariatric surgery: A case of a potentially life-threatening delayed complication.

Hyperammonaemia is a life-threatening condition with numerous aetiologies and a variable presentation. It is increasingly associated with bariatric weight-loss procedures and significant mortality despite treatment. Symptoms often occur long after surgery and at times in association with other trigger illnesses. Patients can present to general medicine, general practice and intensive care as well as surgical and anaesthetic teams. We present the case of a male patient who underwent a sleeve gastrectomy with subsequent weight loss and suffered from hyperammonaemic encephalopathy on multiple occasions. His delayed postoperative complication was likely to be multifactorial in nature, and this is outlined in the case. We discuss presentation, investigation, management and patient outcomes.

Intraoperative hand strength as an indicator of consciousness during awake craniotomy: a prospective, observational study.

Awake craniotomy enables mapping and monitoring of brain functions. For successful procedures, rapid awakening and the precise evaluation of consciousness are required. A prospective, observational study conducted to test whether intraoperative hand strength could be a sensitive indicator of consciousness during the awake phase of awake craniotomy. Twenty-three patients who underwent awake craniotomy were included. Subtle changes of the level of consciousness were assessed by the Japan Coma Scale (JCS). The associations of hand strength on the unaffected side with the predicted plasma concentration (Cp) of propofol, the bispectral index (BIS), and the JCS were analyzed. Hand strength relative to the preoperative maximum hand strength on the unaffected side showed significant correlations with the Cp of propofol (ρ = - 0.219, p = 0.007), the BIS (ρ = 0.259, p = 0.002), and the JCS (τ = - 0.508, p = 0.001). Receiver operating characteristic curve analysis for discriminating JCS 0-1 and JCS ≥ 2 demonstrated that the area under the curve was 0.76 for hand strength, 0.78 for Cp of propofol, and 0.66 for BIS. With a cutoff value of 75% for hand strength, the sensitivity was 0.76, and the specificity was 0.67. These data demonstrated that hand strength is a useful indicator for assessing the intraoperative level of consciousness during awake craniotomy.

Best Practices Using Ex Vivo Animal Brain Models in Neurosurgical Education to Assess Surgical Expertise.

BACKGROUND: Ex vivo animal brain simulation models are being increasingly used for neurosurgical training because these models can replicate human brain conditions. The goal of the present report is to provide the neurosurgical community interested in using ex vivo animal brain simulation models with guidelines for comprehensively and rigorously conducting, documenting, and assessing this type of research. METHODS: In consultation with an interdisciplinary group of physicians and researchers involved in ex vivo models and a review of the literature on the best practices guidelines for simulation research, we developed the "ex vivo brain model to assess surgical expertise" (EVBMASE) checklist. The EVBMASE checklist provides a comprehensive quantitative framework for analyzing and reporting studies involving these models. We applied The EVBMASE checklist to the studies reported of ex vivo animal brain models to document how current ex vivo brain simulation models are used to train surgical expertise. RESULTS: The EVBMASE checklist includes defined subsections and a total score of 20, which can help investigators improve studies and provide readers with techniques to better assess the quality and any deficiencies of the research. We classified 18 published ex vivo brain models into modified (group 1) and nonmodified (group 2) models. The mean total EVBMASE score was 11 (55%) for group 1 and 4.8 (24.2%) for group 2, a statistically significant difference (P = 0.006) mainly attributed to differences in the simulation study design section (P = 0.003). CONCLUSIONS: The present findings should help contribute to more rigorous application, documentation, and assessment of ex vivo brain simulation research.

Integrated care pathways in neurosurgery: A systematic review.

INTRODUCTION: Integrated care pathways (ICPs) are a pre-defined framework of evidence based, multidisciplinary practice for specific patients. They have the potential to enhance continuity of care, patient safety, patient satisfaction, efficiency gains, teamwork and staff education. In order to inform the development of neurosurgical ICPs in the future, we performed a systematic review to aggregate examples of neurosurgical ICP, to consider their impact and design features that may be associated with their success. METHODS: Electronic databases MEDLINE, EMBASE, and CENTRAL were searched for relevant literature published from date of inception to July 2020. Primary studies reporting details of neurosurgical ICPs, across all pathologies and age groups were eligible for inclusion. Patient outcomes in each case were also recorded. RESULTS: Twenty-four studies were included in our final dataset, from the United States, United Kingdom, Italy, China, Korea, France, Netherlands and Switzerland, and a number of sub-specialties. 3 for cerebrospinal fluid diversion, 1 functional, 2 neurovascular, 1 neuro-oncology, 2 paediatric, 2 skull base, 10 spine, 1 for trauma, 2 miscellaneous (other craniotomies). All were single centre studies with no regional or national examples. Thirteen were cohort studies while 11 were case series which lacked a control group. Effectiveness was typically evaluated using hospital or professional performance metrics, such as length of stay (n = 11, 45.8%) or adverse events (n = 17, 70.8%) including readmission, surgical complications and mortality. Patient reported outcomes, including satisfaction, were evaluated infrequently (n = 3, 12.5%). All studies reported a positive impact. No study reported how the design of the ICP was informed by published literature or other methods. CONCLUSIONS: ICPs have been successfully developed across numerous neurosurgical sub-specialities. However, there is often a lack of clarity over their design and weaknesses in their evaluation, including an underrepresentation of the patient's perspective.

Quadrigeminal Cistern Epidermoid Cyst: Neuroendoscopy and Endoscope-Assisted Supracerebellar Infratentorial Approach.

The pineal region is a complex anatomical location with multiple surrounding important neurovascular structures.1,2 Several approaches to this region have been described, including posterior interhemispheric, transchoroidal, infratentorial supracerebellar, supracerebellar and infracerebellar trans-sinus, and their modifications. Neuroendoscopy and endoscope-assisted surgery have been widely applied to aid resection of pineal region lesions.3-5 A 40-year-old man presented with tonic-clonic seizures and bilateral papillary edema on fundus examination. Computed tomography showed a midline lesion at the level of the quadrigeminal cistern with mass effect on the aqueduct of Sylvius and posterior wall of the third ventricle, triggering obstructive triventricular hydrocephalus. As a first intervention, a third ventriculostomy was attempted unsuccessfully owing to unfavorable third ventricle floor anatomy. This approach was used to obtain a biopsy specimen, which showed an epidermoid cyst. Ventriculoscopy showed a communication of the pineal recess and quadrigeminal cistern owing to tumor invasion. An external ventricular drain was placed to control the hydrocephalus until complete resection was performed (Video 1). Several days later, tumor resection was carried out via the median supracerebellar infratentorial approach with the patient in semisitting position. After near-total resection under microscope, the third ventricle and both lateral recesses were explored with the endoscope. A small tumor remnant (visible only with endoscope) was identified and removed. This step was essential to achieve complete resection, confirmed by magnetic resonance imaging. The patient was discharged 6 days later without complications. During follow-up, the patient remains asymptomatic. The combination of microneurosurgery, neuroendoscopy, and endoscope-assisted surgery improves management of pineal region lesions and facilitates complete resection.

Shear wave elastography for intracranial epidermoid tumors.

BACKGROUND: Ultrasound elastography (USE) is a novel technique that assesses the mechanical properties of body tissues in real time. Based on elasticity measurements, USE enables the differentiation of tumor tissue from surrounding normal tissue. OBJECTIVES: We aimed to evaluate an intraoperative SWE technique for differentiating tumor tissue (epidermoid cyst) from the surrounding normal brain tissue based on elastic properties. METHODS: We prospectively report the intraoperative elasticity assessments of four patients diagnosed with epidermoid cysts. Along with standard ultrasonography, intraoperative shear wave elastography (SWE) was used to identify tumor tissue and assess the elasticity of each tumor and the surrounding normal brain. RESULTS: USE enabled the differentiation between epidermoid cysts and the surrounding normal brain tissue in real time intraoperatively; visual data (SWE elasticity map) and quantitative data (elasticity measurements in kilopascals) were utilized to identify the epidermoid cyst based on its elastic properties. The area representing the epidermoid cyst had an increased elasticity on SWE view and high mean elasticity values (193.7 ± 70.9 kPa in case 1, 168 ± 24.5 kPa in case 2, 205.1 ± 6.7 kPa in case 3, and 101.3 ± 12.6 kPa in case 4). The area representing the adjacent normal brain tissue on SWE view had lower mean elasticity values (14.9 ± 1.9 kPa in case 1, 22.6 ± 8.3 kPa in case 2, and 23.8 ± 1.4 kPa in case 4). CONCLUSION: This study demonstrates the feasibility and promising value of SWE as an intraoperative tool during epidermoid cyst resection. Epidermoid tissue remnants that are hidden from the microscopic view can be detected using SWE.

Effectiveness of a Standardized External Ventricular Drain Placement Protocol for Infection Control.

INTRODUCTION: Placement of an external ventricular drain (EVD) is a common procedure routinely completed at bedside by neurosurgical residents. A standardized protocol for placement and maintenance of an EVD is potentially useful. METHODS: This single-institution retrospective review analyzed all patients who underwent placement of an EVD over a 5-year span using a standardized protocol. RESULTS: A total of 428 EVDs in 381 patients were placed as per this protocol. Overall compliance with the practice protocol was 98.7%. Overall, our infection rate was 1.86% (8 external ventricular drain-related infection [ERIs] over 428 EVDs). There was no difference in age for the ERI cases (median 55, range (50.5-60.5), compared with the non-ERI cases (median of 53, range [38-65]) (P = 0.512). Indications for placement of EVD were hemorrhage (51.9%, n = 198), tumor (16.2%, n = 62), trauma (12.8%, n = 49), hydrocephalus (11.5%, n = 44), cerebellar stroke (2.8%, n = 11), infection (3.1%, n = 12), unknown (1.3%, n = 5). Most EVDs (77.6%, n = 296) were placed bedside by second-year residents (median PGY level 2, interquartile range 1-2.75). Computed tomography confirmed placement in the ipsilateral frontal horn in 72% (n = 277) of EVDs. EVD-related complications were noted in 8.3% of EVDs (n = 32, with 8 infections and 24 tract hemorrhages). The median EVD duration was 10 days; duration of EVD had no statistically significant impact on the risk of an ERI (P = 1). Only replacement of an EVD was associated with an increased risk of infection. CONCLUSIONS: Adherence to a standard EVD placement protocol is useful in maintaining a low risk of ERI regardless of the duration of catheter utilization. Replacement of the catheter through the same access hole as the original catheter is associated with an increased risk of ERI.

Surgical management outcome of cerebral schistosomiasis: a case report and review of the literature.

BACKGROUND: Schistosomiasis is a parasitic infection that commonly affects the gastrointestinal and genitourinary tracts. Cerebral schistosomiasis is rare, and few operative cases have been reported in the literature. Diagnosis is usually challenging due to the similarity of the lesion to many other brain conditions. Treatment usually requires surgical resection combined with the use of antiparasitic agents, which often results in good outcomes and excellent prognosis. CASE PRESENTATION: A 24-year-old, previously healthy Afro-asiatic man presented to our neurosurgical outpatient clinic complaining of headache and an attack of convulsions. On examination, he had bilateral lower limb weakness more on the right side. Laboratory investigations including stool and urine general test results were unremarkable. Magnetic resonance imaging of the brain was performed and showed an intra-axial left parietal mass; a granulomatous lesion was suggested in the differential diagnoses. The patient underwent craniotomy and total resection of the lesion. Histopathology confirmed the presence of active cerebral Schistosoma mansoni infection. Orally administered praziquantel was initiated at a dose of 20 mg/kg twice a day for a total of 3 days along with oral administration of corticosteroids for 2 weeks. The patient improved postoperatively without residual weakness and with no further convulsions. CONCLUSION: Cerebral schistosomiasis is a rare but important consideration in the list of differential diagnoses of cerebral space-occupying lesions. This is of particular importance in in endemic areas like Sudan. In order to reach a diagnosis, careful social and occupational history need to be obtained and correlated with the clinical, laboratory, and radiological findings. Surgical resection along with the use of proper antiparasitic agents usually provides the best clinical outcomes.

Calcifying Pseudoneoplasm of the Neuraxis: From Pathogenesis to Diagnostic and Therapeutic Considerations.

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare tumefactive lesion that can develop anywhere within the neuraxis. The incidence is likely underreported, given its nonspecific imaging features and because CAPNON has often been overwhelmed by the presence of comorbid disease. CAPNON is typically diagnosed by the histopathological examination findings. However, the histopathological diagnosis is often challenging owing to the existence of similar calcifying pathological entities. Although the pathogenesis of CAPNON has remained elusive, emerging evidence supports a reactive proliferative and immune-mediated process involving the aggregation of neurofilament light chain protein and the infiltration of immune cells. The management of CAPNON is largely dependent on the symptoms, which are mainly related to the location and associated mass effects. Maximal surgical resection will result in excellent patient outcomes with rare recurrence, especially in patients presenting with epilepsy. The discovery of neurofilament light chain protein within CAPNON suggests that neurofilament might be implicated in the pathogenesis of CAPNON, serve as an immunohistochemical marker to improve the diagnostic accuracy of CAPNON, and hold therapeutic potential for the treatment of CAPNON.

A novel omnidirectional tin-alloyed ring retractor for craniotomy in neurosurgery: technical note.

In neurosurgical operations, proper craniotomy using retractors is necessary. Various surgical instruments are used for this purpose, including standard retractors and multipurpose head frame retractor systems. However, the conventional multipurpose head frame system is often not optimal for use in some craniotomies and postures because of its size and complexity of setting. We have invented a new omnidirectional tin-alloyed (ODT) ring retractor for craniotomy with malleability and shape memory characteristics to resolve these issues. It is principally elliptical in shape, approximately 30 × 20 cm in diameter, and sufficiently firm. Accordingly, this ODT ring can retract the surgical field in all directions. Here, we report our experiences of 281 neurosurgical craniotomies using this ODT ring retractor system in various craniotomy sites and postures. Our novel ODT ring retractor is useful because of its low profile, multidirectional retractability, and less obstructiveness with its malleability. It could be used with pediatric patients where strong traction is not desirable.

Optical coherence tomography of cranial dura mater: Microstructural visualization in vivo.

PURPOSE: The study explores microscope integrated optical coherence tomography (OCT) as a intraoperative imaging technique to delineate the microstructural composition of human dura mater cranialis and underlying leptomeninges for surgical guidance. METHODS: OCT volume scans, light microscopic pictures and light microscopic videos of the dura mater were acquired in patients (n = 20) with indication for craniotomy. OCT volume scans and corresponding light microscopic data were analyzed post procedural. Thickness of anatomical structures was measured during this phase. RESULTS: OCT scanning of the human cranial dura mater was feasible during microsurgical dissection. A discrimination of the endosteal and inner meningeal layer of the cranial dura mater was possible in 70 % (n = 14) of the patients. Transdural OCT scans could further demonstrate subdural anatomical structures: subdural space 10 % (n = 2), subarachnoid space in 35 % (n = 7), arachnoid vessels in 80 % (n = 16) and brain cortex in 90 % (n = 16) of the patients. Orthogonal distance measurement was possible. The cranial dura mater showed a mean depth of 216 µm, the endosteal layer of 120 µm and the inner meningeal layer of 132 µm. Imaging quality of the dural segment was high - approaching spatial resolution of histopathology. Imaging quality of subdural segments was lower and demonstrated A-line artifacts in 45 % (n = 7). CONCLUSION: These results illustrate - for the first time - strengths and weaknesses of three dimensional microscope integrated OCT as an in vivo imaging method of the human cranial dura mater, underlying leptomeninges and human brain cortex as a surgical guidance tool. OCT imaging of the cranial dura mater showed extensive details. Transdural imaging of subdural micro anatomical structures was possible, but showed lower image quality with intermittent A-line artifacts. OCT stated the first intraoperative imaging tool to measure the depth of micro anatomical structures with a high spatial resolution of 7,5 µm.