Foramen magnum meningioma: Series of 20 cases. Complications, risk factors for relapse, and follow-up.

INTRODUCTION: Meningiomas account for 2.2% to 2.5% of all cerebral tumors, of which only 2% are located in the foramen magnum. Foramen magnum meningiomas (FMMs) are commonly found in women, with a mean age at onset of 52 years old. They generally behave more aggressively than other meningiomas. MATERIALS AND METHODS: We performed epidemiological, anatomical and surgical analyses of 20 patients diagnosed with FMMs who underwent surgical treatment from 1999 to 2019 at Santa Paula Hospital in Sao Paulo. This case series was compared with previously published ones to better understand this relatively rare disease. RESULTS: Twenty patients were included, with a mean follow-up of 110 months. Their mean age was 37.8 years old. The mean preoperative Karnofsky performance status scale (KPS) was 84%. We found a female (65%) and left hemisphere predominance (50%). Involvement of both hemispheres was found in 25% of patients. FMM locations were anterior, anterolateral, lateral and posterior, in 45%, 35%, 10%, and 10%, respectively. Simpson resection grades I, II, and III were achieved in 25%, 60%, and 15% of cases, respectively. Mean postoperative KPS was 79%. Three patients with anterior and bilateral located meningiomas had a worse postoperative KPS in comparison to the preoperative one. CONCLUSION: Anterior and bilateral FMMs seem to be related to a worse prognosis. A gross total resection can reduce the recurrence rates. The KPS is worse in patients with recurrence.

Rare complication of ventriculoperitoneal shunt: Ectopic distal catheter in a Grynfeltt hernia - case report.

BACKGROUND: Ventriculoperitoneal shunts (VPSs) insertion is the most common used intervention in cases of hydrocephalus. The main postoperative complications are infections and catheter obstructions. Although the literature has well-documented cases describing migration of the distal catheter, this rare presentation can become more confusing when occurring in conjunction with some unusual preexistent morbidity in the patient, as a Grynfeltt hernia. CASE DESCRIPTION: This study reports a rare case of a VPS postoperative migration, in which the distal catheter exits the abdominal cavity through a Grynfeltt hernia. This condition was not discovered until the catheter fistulated through the overlying skin. The Grynfeltt hernia is the most uncommon among the lumbar ones and it's asymptomatic in the majority of the cases, being hardly diagnosed. CONCLUSION: The unusualness of the reported case deserves furthermore discussion to properly evaluate these underlying mechanisms of catheter migration.