The sellar barrier on preoperative imaging predicts intraoperative cerebrospinal fluid leak: a prospective multicenter cohort study.

BACKGROUND: The type of sellar barrier observed between a pituitary tumor and cerebrospinal fluid (CSF) on preoperative magnetic resonance imaging (MRI) may predict intraoperative CSF leak during endonasal pituitary surgery. This is the first multicentric prospective cohort trial to study the sellar barrier concept and CSF leak rate during endoscopic pituitary surgery. METHODS: This multi-center, international study enrolled patients operated for pituitary adenomas via fully endoscopic endonasal surgery over a period of 4 months. The independent variable was the subtype of sellar barrier observed on preoperative MRI (strong, mixed or weak); the dependent variable was the presence of an intraoperative CSF leak. The primary goal was to determine the association between a particular type of sellar barrier and the risk of intraoperative CSF leak. Appropriate statistical methods were then applied for data analysis. RESULTS: Over the study period, 310 patients underwent endoscopic endonasal surgery for pituitary tumor. Preoperative imaging revealed a weak sellar barrier in 73 (23.55%), a mixed sellar barrier in 75 (24.19%), and a strong sellar barrier in 162 (52.26%) patients. The overall rate of intraoperative CSF leak among all patients was 69 (22.26%). A strong sellar-type barrier was associated with significantly reduced rate of intraoperative CSF leak (RR = 0.08; 95% CI 0.03-0.19; p < 0.0001), while a weak sellar barrier associated with higher rates of CSF leak (RR = 8.54; 95% CI 5.4-13.5; p < 0.0001). CONCLUSIONS: The preoperative MRI of pituitary patients can suggest intraoperative CSF leak rates, utilizing the concept of the sellar barrier. Patients with a weak sellar barrier carry a higher risk for an intraoperative CSF leak, whereas a strong sellar barrier on MRI seems to mitigate intraoperative CSF leak. We propose that preoperatively assessment of the sellar barrier can prepare surgeons for intraoperative CSF leak repair.

Classification of sphenoid sinus pneumatization: relevance for endoscopic skull base surgery.

OBJECTIVES/HYPOTHESIS: The goal of this study was to present a classification based on the degree of pneumatization of the sphenoid sinus in the coronal plane that can be used to instruct preoperative planning for endoscopic endonasal surgery (EES). STUDY DESIGN: Observational anatomical study. METHODS: The geometry of sphenoid sinus pneumatization was characterized (n = 204 hemisinus) on high-resolution computed tomography scans, and its associations with the location of the foramen rotundum (FR) and the vidian canal (VC) were measured. Based on these findings, we propose a simple classification of pneumatization of the sphenoid sinus relevant for EES. RESULTS: The lateral recess of the sphenoid sinus was pneumatized lateral to the FR in the coronal plane in 54% of patients. The distance separating the FR and the VC correlated strongly with the depth of the lateral recess. Based on these findings, we propose three types of pneumatization: type I, where the pneumatization extends from the midline to the medial edge of the VC (25%); type II, where the pneumatization reaches the medial edge of the FR (39%); and type III, where the pneumatization extends beyond the medial border of the FR (37%). CONCLUSIONS: The proposed sphenoid sinus pneumatization classification in the coronal plane is simple and reproducible. It predicts the distance between vidian and maxillary nerve, determines the size of the surgical window to access the middle cranial fossa transnasally, and instructs on the potential risk to neurovascular structures during surgery.

Surgical removal after first bleeding of an arteriovenous malformation previously obliterated with radiosurgery: case report.

BACKGROUND: Radiosurgery has been widely used to treat cerebral AVMs, providing angiographic evidence of obliteration of the malformation in 80% to 95% of patients, after a latency period of 2 to 5 years. CASE DESCRIPTION: We describe a case of hemorrhage, 6 years after radiosurgery and 4 years after complete angiographic obliteration of an AVM that had not previously bled and that persisted angiographically, obliterated after bleeding. RESULTS: Several treatment options have been reported for patients with completely obliterated AVMs that bled, including conservative treatment, repeated radiosurgery, and open surgery with resection of AVM remnants. In the present case, the decision to perform surgery based on the probable association of the enhancing area observed on the MRI and the histologic findings was finally confirmed. CONCLUSIONS: Magnetic resonance imaging enhancement areas on the obliterated AVMs may have a histopathologic correlation with persistence of permeable vessels and can be used as a guide for surgery and postoperative control. The follow-up of angiographically obliterated AVMs that bleed remains a matter of discussion twofold: regarding timing and use of a proper diagnostic test.