Sternberg’s canal: a rare site of CSF leak—our experience and management of a series of cases at a tertiary care hospital in South India

Background

The lateral craniopharyngeal canal or Sternberg’s canal is located in the postero-lateral part of the sphenoid sinus. It is the weakest area of the skull base, originating due to defective fusion during embryological development in a small proportion of individuals. Hence, it can give rise to CSF leaks from that region. Due to the proximity of this region to the internal carotid artery, optic nerve, and cavernous sinus, it proves to be challenging to repair these defects. The exact location, role in the causation of CSF leaks, and clinical presentation with arachnoid herniation are also subject to much controversy.

Results

In our case series, we describe 7 patients with the rare clinical entity of CSF leak from the Sternberg’s canal, who had a mean age of 38.4 years, 4 of whom also had an arachnoid herniation through the canal. One patient already underwent prior endoscopic surgery for the CSF leak. We highlight a trans-nasal trans-sphenoid approach with multi-layer closure, i.e., fat plug, fascia, and a naso-septal flap with the use of an additional layer of muscle in one of the cases, following which all had good outcomes. Since the primary concern with this rare clinical scenario is correct identification and adequate exposure of the leak for repair, we additionally undertook a trans-pterygoid approach in 2 of our patients.

Conclusions

The key to the successful repair of the Sternberg’s canal leak lies in its accurate identification and exposure. In our series, we achieved good exposure by drilling the pterygoids and lateral sphenoid walls along with the use of angled endoscopes for visualization. Our case series highlights the linear relation of elevated BMI with spontaneous CSF leaks in the absence of benign intracranial hypertension and the reinforcement of repair with the use of a harvested naso-septal flap. Our multi-layered closure ensured good results and no recurrence of a leak in any of our patients.

Neurovascular Surgical Keys Related to Sphenoid Window: Radiologic Study of Egyptian's Sphenoid

OBJECTIVES

The anatomic variations of the sphenoid sinus and its relation to the surrounding neurovascular structures are a subject of interest. The purpose of this study was to radiologically assess the frequency of protrusion/dehiscence of key neurovascular landmarks surrounding the Egyptians' sphenoid.

METHODS

This is a cross-sectional descriptive study of sinonasal computed tomography of the sphenoid sinus in 500 adult Egyptians, conducted at Mansoura University Hospitals; Egypt, over a period of 1 year. Two archives were used for collecting the data; the hard archive and the electronic archive. Variables of interest included the extent of sphenoid sinus pneumatization; intersphenoid septation pattern; protrusion/dehiscence of the internal carotid artery, optic nerve, maxillary nerve, and vidian nerve; and detection of the Onodi cell.

RESULTS

Population of this study included 265 women and 235 men. Their ages ranged from 18-68 years. The bilateral sellar-type pneumatization was shown as the most common pneumatization type (96.8%). Pneumatizations of the pterygoid process, anterior clinoid process, and greater wing of the sphenoid were identified in 9.3%, 8.9%, and 31.8% consequently. A single intersphenoid septum was detected in 85.2%, whereas multiple intersphenoid septums were noted in 11.6%. Protrusion of the internal carotid artery, optic nerve, vidian nerve, and maxillary nerve was recorded in 8.5%, 9.1%, 6.6%, and 3.4% consequently, while dehiscence was reported in 7.2%, 15%, 11.9%, and 4.2% consequently as well. Onodi cell was recognized in 18%.

CONCLUSIONS

This radiologic study highlights significant variations of surgically important anatomic structures related to the sphenoid sinus in Egyptians.

A modification of endoscopic endonasal approach for management of encephaloceles in sphenoid sinus lateral recess

Spontaneous cerebrospinal fluid leak with meningoencephaloceles in sphenoid sinus lateral recess is challenging. Transnasal visualization of this area is difficult, especially when large pneumatization is present. External approaches to this region involve aggressive surgery and are often associated with significant morbidity. The aim of this study is to assess the real effectiveness of a modification of the endoscopic endonasal approach for their management. This is a prospective case series study and was conducted at Otolaryngology department, Ain Shams University Hospitals, Cairo, Egypt. Seven patients with spontaneous cerebrospinal fluid leak with meningoencephaloceles in the sphenoid sinus lateral recess were included. Diagnosis was confirmed by: analysis for beta-2 transferrin and imaging. They were managed with endoscopic endonasal retrograde trans-sphenoid approach described in this study with multilayered reconstruction of the defect. Mean age of our patients was 40.14 ± 8.35 years; mean BMI was 36.37 ± 2.59 kg/m². Primary empty sella was present and osteodural defect was identified in superior wall of sphenoid sinus lateral recess with punched out and regular smooth edges. Mean intra-cranial pressure was (26.42 ± 3.87 mmH₂O) and size of defect was less than 10 mm, mean 7.85 ± 1.34. Mean-operative time was 169.28 ± 21.87 min. The mean hospital stay was 7.42 ± 1.39 days. No cerebrospinal fluid leak recurrences were observed during follow-up period that ranged from 37 to 48 months. Endoscopic endonasal retrograde trans-sphenoid approach provides a wide, safe, and direct route to the management of sphenoid sinus lateral recess cerebrospinal fluid leak.