Sternberg's canal: fact or fiction?

BACKGROUND:Sternberg's (lateral craniopharyngeal) canal was originally described in anatomic studies as a membranous space in the lateral wall of the sphenoid sinus. The canal has been etiologically associated with lateral sphenoid sinus "spontaneous" cerebrospinal fluid (CSF) leaks. A patent Sternberg's canal has been reported in up to 4% of adults, and persistent vestiges have been reported in up to 30%. However, no modern studies analyzing high-resolution CT scans have been published. METHODS:A consecutive analysis of 1000 high-resolution CT scans of sphenoid bones was performed. Scans were analyzed for a lateral recess, bony defects, arachnoid pits, and holes possibly representing Sternberg's canal. Data were compared with a case series of lateral sphenoid CSF leaks. RESULTS:Average patient age was 38.7 years (10-92 years). A sphenoid lateral recess was present in 35.3% (17.4% bilateral) of cases. Arachnoid pits were present on the floor of the middle cranial fossa in 23.4% of cases. Seven skull base defects were identified. Only one traveling medial to V2 resembled the description of Sternberg's canal. In contrast, a case series of 25 patients with lateral sphenoid sinus CSF leaks all had a lateral recess, defects, and arachnoid pits lateral to V2 (p < 0.00001). CONCLUSION:Sternberg's canal as historically defined is not nearly as prevalent as previously reported. Furthermore, the presence of arachnoid pits in all sphenoid CSF leaks and the predominant leak location lateral to the sites of fusion of ossification centers suggests that the leaks are acquired. Contributing factors may include arachnoid pits/weaknesses in the skull base and intracranial hypertension.