How To: Prelacrimal–Transmaxillary Approach to Lateral Sphenoid Recess Skull Base Defects

INTRODUCTION

Well-pneumatized lateral sphenoid recess lesions have been a challenge to access surgically. Various endonasal surgical techniques for the sphenoid sinus have been described, including transethmoid, transnasal, and transseptal approaches. These techniques have limitations, however, particularly in reaching/accessing the lateral limit of a well-pneumatized sphenoid sinus. Access to the lateral recess of the sphenoid sinus is usually limited inferiorly and laterally by the root of the pterygoid plates and the sphenopalatine foramen. In 1999, Bolger described the endoscopic transpterygoid approach to the lateral sphenoid recess and further expanded on this technique in a series of nine patients. This was a transmaxillary approach, via a wide antrostomy, to preserve the Vidian and descending V2 nerve roots. Various modifications to this technique have been described to further improve access. In each modification, access to the lateral recess was achieved using various angled scopes and curved instruments through a large maxillary antrostomy. We describe a modification of this approach, the prelacrimal–transpterygoid/maxillary approach (PTMA), which allows direct access with a straight trajectory to the lateral recess of the sphenoid sinus via a direct transmaxillary route, and the associated outcomes.

MATERIALS AND METHODS

A retrospective chart review of consecutive adult patients with pathology in the sphenoid sinus managed with PTMA was performed. This study was approved by St Vincent’s Hospital Human Research Ethics Committee (2019/PID13822).

Outcomes

The primary outcome was operative success defined as accessing the lateral recess of the sphenoid sinus and successful surgical treatment of the underlying pathology. Secondary outcomes were lateral wall integrity (or remucosalization), early surgical morbidity (<90 days), and late surgical morbidity (>90 days).

Early morbidity included infection, paraesthesia along the maxillary branch of the trigeminal nerve (V2), cerebrospinal fluid (CSF) leak, bleeding, mucosal necrosis, adhesions, and skin changes. Late morbidity included recurrence requiring revision surgery, CSF rhinorrhoea, dry eye, epiphora, inferior meatal communication, stenosis, V2 paraesthesia, and cosmetic change. Raised intracranial pressure was defined as >22 cm H₂O on intrathecal pressure monitoring. No patient had active lumbar drainage used in the recovery period.

Surgical Technique

The modified prelacrimal approach (PLA) has been previously described. In this series, a spheno-ethmoidectomy and maxillary antrostomy are performed prior to post-operative irrigation and surveillance. A posterior-based mucosal flap is then elevated subperiosteally, commencing with a lateral nasal wall incision above the axilla of the middle turbinate near the nasal roof using needle-point diathermy coagulation, setting 12 W (0016 AM Megadynne, N.J.). This incision is then continued anteriorly and inferiorly to the bony pyriform aperture and then continued inferiorly to the floor of the nasal cavity and then medially to the nasal septum. The incision then extends posteriorly along the floor of the nose adjacent to the septum to the depth/level of the middle meatus. The mucosa is then elevated, and the inferior turbinate bone is separated from the mucosa in the subperiosteal plane, identifying and mobilizing the membranous nasolacrimal duct (NLD), removing the surrounding bone with a Kerrison rongeur. A “perilacrimal” surgical corridor is then created with a 4-mm 15° diamond burr, allowing access to the maxillary sinus and posterior maxillary wall (Fig. 1).