Endoscopic Endonasal Transpterygoid Approach to Sphenoid Sinus Lateral Recess Defects

Abstract

Background Lesions affecting sphenoid sinus lateral recess (SSLR) are difficult to visualize and manipulate through the transnasal routes, especially when the sinus is highly pneumatized. External approaches to this area involve extensive surgery and are associated with significant morbidity. The aims of this study are to present our experience with the endoscopic transpterygoid approach as a method for approaching lesions of the SSLR and to evaluate the outcomes of this procedure. Methods Clinical charts of patients who had lesions in the SSLR and who were treated at our institution from September 1998 to June 2018 were retrospectively reviewed. All these patients were managed by the endoscopic endonasal transpterygoid approach. Results Thirty-nine patients were identified. No cerebrospinal fluid leak recurrences were observed during follow-up (range: 1-19.7 years; median: 2.3 years). Hypoesthesia (temporary, 1; persistent, 4) in the region innervated by the maxillary branch of the trigeminal nerve was detected in five (12.8%) patients, while symptoms due to the Vidian nerve damage (dry eye, 3; dry nasal mucosa, 1) were present in four (10%) patients. Conclusions Although the endoscopic endonasal transpterygoid approach is an excellent corridor for dealing with lesions of the SSLR, limited rate of neurologic and lacrimal complications was observed. Potential morbidity of the intervention should be discussed during preoperative counselling.

Keywords: cerebrospinal fluid leak; endoscopic transpterygoid approach; meningoencephalocele; skull base; sphenoid sinus lateral recess.

Fig. 1

The V-R line (red line) which connects the medial edge of the foramen rotundum and Vidian canal is defined as the demarcation between the sphenoid body and lateral parts of sphenoid bone (greater wings superiorly and pterygoid process inferiorly). The sinus extends laterally into both the greater wing and the pterygoid process bilaterally. Note the bilateral defects (*) in the middle fossa floor lateral to the V-R line with a soft tissue density mass filling the sphenoid sinus suggesting encephalocele. V-R, Vidian-Rotundum.

Fig. 2

Endoscopic picture showing left SSLR leak and repair of defect using gasket-seal closure. ( A ) Following total sphenoethmoidectomy, middle turbinate is resected (MT indicating its original attachment). Nasoseptal flap stored in the choana during the surgical procedure. ( B ) The sphenoid sinus anterior wall till the lateral end of the recess and anterior aspect of pterygoid bone floor were drilled as lateral as the anterior orifice of the VC with a high-speed diamond drill (Midas Rex; Medtronic, Humacao, Puerto Rico, United States). Paraclival segment of the internal carotid artery and medial pterygoid plate are seen. ( C ) After completion of bone drilling, adequate surgical space was gained to expose the MEC and osteodural defect localized in SSLR. ( D ) MEC was reduced in size by endoscopic bipolar and complete mucosal extirpation from the SSLR was performed. ( E ) Better visualization of osteodural defect (*) by a 45- angled endoscope. ( F ) A piece of fascia lata is fashioned to be larger than the bone defect. The fascia lata is centered over the defect and a piece of cartilage roughly the size of the defect in the cranial base is harvested from the septum. This piece of cartilage is centered over the fascia lata. The cartilage buttress is then wedged in place and the redundant fascia lata is draped around the bone, creating a watertight seal. ( G ) SSLR is obliterated with a free fat graft. ( H ) Nasoseptal flap positioned over the obliterated SSLR. C, cartilage; FL, fascia lata; MEC, meningoencephalocele; MPP, medial pterygoid plate; MT, middle turbinate; NSF, nasoseptal flap; SSLR, sphenoid sinus lateral recess; VC, Vidian canal.

Fig. 3

A 67-year-old female patient with a body mass index of 27.0 kg/m ² had undergone two prior sphenoidotomies with “packing” without identification and repair of the associated encephalocele and skull base defect. She presented to us with clear rhinorrhea with a history of two meningitis attacks. Coronal images, T2-weighted ( A ) and T2 fluid attenuated inversion recovery ( B ), show an encephalocoele raising from the right temporal lobe. Sagittal T2 magnetic resonance imaging. Red arrow shows right sphenoid sinus lateral recess defect accompanying meningoencephalocele, and the asterisk indicates total empty sella ( C ). At 2 years postoperative control, images in the same sequences obtained postoperatively ( D – F ) demonstrated complete healing in the operation site.

Fig. 4

Surgical trajectories demonstrating the direct access attained with EETSA, EETESA, and EETPA approaches. Blue dotted line, access attained with EETSA; red dotted line, access attained with EETESA; green dotted line, the enhanced lateral extent afforded with EETPA; white dotted line, midline. The axial computed tomography scan demonstrates how this skull base defect is inaccessible using the transethmoidal endoscopic technique owing to the far lateral and inferior location of the defect in the hyperpneumatizated SSLR (encephalocele) (arrow). EETESA, endoscopic endonasal transethmoidal-sphenoidal approach; EETPA, endoscopic endonasal transpterygoid approach; EETSA, endoscopic endonasal trans-sphenoid approach; SSLR, sphenoid sinus lateral recess.