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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. [ABSTRACT FROM AUTHOR]

Surgical brain injury caused by brain retraction is a well-known consequence of intracranial surgery. Modern retractor designs, particularly since the 1980s, have significantly improved ease of use, improved visibility for surgeons, and minimized retraction-induced injuries, though not yet been entirely eliminated. Today, brain retractors come in a broad range of styles, each with its own pros and cons regarding operational utility and patient safety. Which type is chosen for use depends on the surgical approach, lesion size and depth, cost, and surgeon preference. Traditionally, self-retaining brain retractors with moveable arms and 1 or more attachable blades made from malleable stainless steel or silicone rubber have been the tool of choice; however, recently tubular retraction systems that only require fixation to the head frame and cause less focal pressure damage than older retractors have gained in popularity for some cases. This review aims to address the history of brain retraction and discuss each of the commonly used brain retractor types, as well as some newer and less common varieties especially in terms of the extent of tissue damage typically caused as well as the types of injuries reported by the users. [ABSTRACT FROM AUTHOR]

An intraoperative technique for foramen magnum decompression of Chiari malformation is presented. The technique uses minimal exposure tubular retractors attached to a flexible arm to keep the retractor in a fixed position, while allowing flexible angulation under fluoroscopic guidance. Operations were performed between 2009 and 2018 on 22 patients with cerebellar tonsillar descent below the foramen magnum and a diagnosis of type I Chiari malformation. A linear durotomy was necessary, but only the outer layer of the dura was opened for some patients, which is less invasive than the traditional procedure where a durotomy is performed for both the inner and outer layers, and then a duraplasty is performed. The approach allowed access to a wide working area, minimized soft tissue exposure, and optimized extent of decompression. The postoperative imaging demonstrated satisfactory bony removal, and magnetic resonance imaging of the area with cerebrospinal (CSF) flow study showed good CSF flow across the foramen magnum. There was a low incidence of postoperative complications, and the average length of hospital stay was 1 day. For 19 of 22 cases, the symptoms completely resolved or markedly improved, and each of the patients who attended the last follow-up demonstrated syrinx resolution. Based on our experience with this technique, when used to assist in foramen magnum decompression of Chiari malformation I, the minimally invasive tubular retractor is a useful tool, providing the surgeon with enhanced visualization of the operative field, while reducing potential damage to tissue and optimizing surgical outcomes. [ABSTRACT FROM AUTHOR]

Highlights • Ependymoma may develop atypically in the background of Parkinson's disease (PD). • Ependymoma associated with PD may show unusual imaging and pathologic features. • α-Synucleinopathy may be involved in the tumorigenesis of ependymomas. Abstract The diagnosis and management of ependymoma may be challenging when there is a comorbidity of ependymoma and Parkinson's disease (PD). We report the first case to demonstrate unusual clinical and pathological features of an ependymoma associated with PD. A 77-year-old male with a history of PD had brain magnetic resonance imaging (MRI) that showed signal abnormalities in the right temporal lobe, most consistent with a low-grade glioma. He underwent an imaging-guided resection of that lesion, which pathological examination revealed mild hypercellularity with gliosis but no neoplasm, as well as Lewy bodies (LBs) and α-synucleinopathy in the temporal cortex compatible with advanced PD. Follow-up MRI exhibited tumor-like progression of signal abnormalities in that brain region. Twenty-nine months after the first resection, a head computerized tomography scan disclosed an obvious mass centered in the right temporal lobe. A second resection was performed for the mass, which pathological examination revealed an ependymoma with focal anaplasia and additional unusual features including an infiltrative growth pattern and intermixed α-synuclein positivity with electron microscopy finding of LB-like inclusions. Our observation suggests that an ependymoma in the patient with PD may present with unusual features possibly due to altered tumorigenesis and disease progression associated with α-synucleinopathy. [ABSTRACT FROM AUTHOR]

Colloid cysts are rare developmental lesions, accounting for approximately 1% of intracranial tumors. Often, these benign lesions are asymptomatic, but they are associated with significant mortality as a result of acute hydrocephalus. This mortality in patients with vague or no symptoms dictates a need for better understanding of the etiology of colloid cysts to expedite diagnosis and management. We present a case of monozygotic twins with colloid cysts to propose a genetic etiology for colloid cyst. Previously healthy male monozygotic twins presented 4 years apart with headache secondary to hydrocephalus as a result of colloid cysts. Both patients underwent multiple surgeries and were doing well at last follow-up. The present case adds to a body of literature of familial colloid cysts, suggesting higher concordance in monozygotic compared with dizygotic twins. This may be due to high genetic load, shared intrauterine environment, epigenetic changes, or genetic mutation. This literature review suggests that given high morbidity and mortality of colloid cysts, screening may be beneficial. Even in the absence of a single, definitive genetic etiology, we recommend consideration of genetic screening or, at a minimum, screening with neuroimaging for monozygotic twins in cases where 1 twin is diagnosed with colloid cyst. [ABSTRACT FROM AUTHOR]

To analyze and find risk factors associated with developing transient diabetes insipidus (DI) using a multicenter case series after trans-sphenoidal surgery. Medical records of patients who underwent trans-sphenoidal surgery for pituitary adenoma resection between 2010 and 2021 at 3 different neurosurgical centers by 4 experienced neurosurgeons were retrospectively analyzed. The patients were divided into 2 groups (DI group or control group). Logistic regression analysis was conducted to identify risk factors associated with postoperative DI. Univariate logistic regression was performed to identify variables of interest. Covariates with a P value <0.05 were incorporated into multivariate logistic regression models to identify independently associated risk factors for DI. All statistical tests were conducted using RStudio. A total of 344 patients were included; 68% were women, the mean age was 46.5 years, and nonfunctioning adenomas were the most frequent (171, 49.7%). The mean tumor size was 20.3 mm. Covariates associated with postoperative DI were age, female gender, and gross total resection. The multivariable model showed that age (odds ratio [OR] 0.97, CI 0.95–0.99, P = 0.017) and female gender (OR 2.92, CI 1.50–6.03, P = 0.002) remained significant predictors of DI development. Gross total resection was no longer a significant predictor of DI in the multivariable model (OR 1.86, CI 0.99–3.71, P = 0.063), suggesting that this variable may be confounded by other factors. The independent risk factors for the development of transient DI were female and young patients. [ABSTRACT FROM AUTHOR]

This study analyzed patient, radiologic, and clinical factors associated with operative brain abscesses and patients' functional outcomes. A retrospective analysis was conducted of neurosurgical cases of brain abscesses from 2009 to 2019 at a Canadian center. Functional outcome was recorded as Modified Rankin Scale score and Extended Glasgow Outcome Scale score. Multivariate analysis was conducted to identify relevant prognostic factors. We identified 139 patients managed surgically for brain abscesses. Resection alone was performed in 64% of patients, whereas 26.6% underwent aspiration alone. Most were adults (93.2%) and male (68.3%). Immunocompromise risk factors included diabetes (24.5%), cancer (23.7%), and immunosuppressive therapy (11.5%). Likely sources were postoperative (17.3%), systemic spread (16.5%), and poor dentition (12.9%). Microorganisms cultured from abscess samples were mixed growth (28%), Streptococcus anginosus (24.5%), and Staphylococcus aureus (7.9%). Disposition was home (42.4%) or repatriation to a home hospital (50.4%). By Extended Glasgow Outcome Scale, 25.2% had an unfavorable outcome including a mortality of 11.5%. Factors on multivariate analysis associated with poor outcome included diabetes (odds ratio, 2.8; 95% confidence interval [CI], 1.2–5.0) and ventricular rupture (odds ratio, 5.0; 95% CI, 1.7–13.5; hazard ratio, 12; 95% CI, 3.9–37.0). Supratentorial superficial eloquently located abscess was also associated with poor outcome (hazard ratio, 5.5; 95% CI, 1.8–16.7). Outcomes were similar with surgical excision and aspiration. Ventricular rupture and diabetes are significant risk factors for poor outcomes in intraparenchymal brain abscesses. No clear difference in outcomes was found between surgical excision or aspiration in our retrospective cohort. [ABSTRACT FROM AUTHOR]

The endoscopic endonasal approach (EEA) has been increasing in popularity as an alternative to traditional transcranial and transorbital approaches in the treatment of orbital pathological entities. The purpose of the present study was to examine the outcomes of patients who had undergone EEA resection of orbital lesions at our center. We performed a retrospective medical record review of patients who had undergone the EEA for resection of orbital lesions and orbital apex decompression from January 1, 2006 to December 1, 2019. For all the patients, the demographic data, presenting symptoms, symptom duration, imaging data, operative details, and postoperative outcomes were collected and reviewed. Nine patients underwent endoscopic endonasal resection of orbital lesions and orbital apex decompression at our center, including 6 male patients and 3 female patients. The mean age was 49.4 years, and the mean follow-up period was 3.8 years (range, 1–13.5 years). The orbital pathological lesions that were treated included nasopharyngeal carcinoma, hemangioma, fibrous dysplasia, IgG4 pseudotumor, inverted papilloma, angioleiomyoma, adenocarcinoma, and neuroendocrine paraganglioma metastasis. All the patients presented with exophthalmos of the affected orbit. Of the 9 patients, 5 presented with decreased visual acuity on examination. Postoperatively, 1 of these 5 patients had improved to baseline visual acuity, 3 had stable vision, and 1 had brief improvement before experiencing progressive visual decline 1 month postoperatively. Two patients presented with diplopia, and both improved postoperatively. Three patients experienced new, transient, and self-limiting postoperative diplopia. For patients with orbital lesions causing compressive optic neuropathy, the endoscopic endonasal approach can be used as an alternative strategy in appropriately selected patients. [ABSTRACT FROM AUTHOR]

Background The trigeminocardiac reflex is a sudden onset of bradycardia, hypotension, apnea, or gastric hypermotility in response to stimulation of the trigeminal nerve. Case Description A 60-year-old female underwent a left orbitozygomatic craniotomy to debulk a large skull base epidermoid cyst compressing the brainstem and cranial nerves. Intraoperatively, retraction of the temporalis muscle consistently produced asystole. Cessation of retraction resulted in prompt return of sinus rhythm. Conclusions Our report describes an unusual and extreme example of the trigeminocardiac reflex and explores possible etiologies. This is the third reported surgical case in which manipulation of the temporalis muscle alone was sufficient to elicit bradycardia and asystole, and the first such case within the context of neurosurgery. We emphasize the importance of surgical teams to be cognizant of such extreme examples of this reflex. [ABSTRACT FROM AUTHOR]

Background Endoscopic third ventriculostomy (ETV) is a safe and effective treatment for hydrocephalus. An entry point located 4 cm anterior to the coronal suture, 3 cm anterior to Kocher point, and approximately 9 cm from the pupil at the midpupillary line has been used successfully for the last 20 years in our center. We aimed to evaluate this alternative anterior entry point routinely used for ETV, with or without concurrent endoscopic biopsy. Methods Patients undergoing this proposed entry point were examined to evaluate its safety and efficacy. Factors such as patients' age, sex, hydrocephalus etiology, tumor location and pathology, and complication rate were examined through regression analyses to evaluate their impact on tumor biopsy and ETV success rates, and the need for subsequent ventricular shunting. Results A total of 131 patients were included in the study. ETV was successful in 125 (95.4%) patients. Of these, 26 (19.8%) patients required a biopsy, which was successful in 21 (80.8%) cases. A complication was observed in 10 (7.6%) patients, with a trend toward complications occurring after ETV failure. There was no association between ETV success rate and patients' age ( P = 0.5) or sex ( P = 0.99). Conclusions The anterior entry point is a safe and effective method for ETV, especially when considering concurrent ventricular tumor biopsy. This entry point may be considered as a more minimally invasive procedure when using rigid endoscopy and may also eliminate the need for a flexible scope. [ABSTRACT FROM AUTHOR]