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).

The posterior wall of the maxillary sinus can be accessed through this perilacrimal corridor, and mucosa from the posterior wall is marked with a diathermy and taken down. The bony back wall of the posterior maxillary sinus is then removed medial to the infraorbital nerve with a Kerrison rongeur. The fascia over the pterygopalatine fossa contents is cauterized with bipolar electrocautery, and the internal maxillary artery is dissected and either mobilized away from the field of view or ligated with medium endoscopic clips via a 5-mm laparoscopic clip applicator (Ligamax 5MM Endoscopic Multiple Clip Applier, Ethicon, N.J.) and divided. The periosteum over the pterygoid process is elevated, and the pterygoid process is drilled with a 4-mm 15° diamond burr (IPC, Medtronic, Fla.) lateral to the sphenopalatine foramen, Vidian canal, and medial to the infraorbital nerve. Direct access to the lateral sphenoid recess is then achieved with a 0° endoscope. The underlying pathology is then able to be addressed, and multilayer reconstruction is achieved through this access. Our preference is to preserve the lateral recess and remove mucosa only immediately around the defect to receive a limited mucosal graft. If the lateral recess is to be obliterated, then the entire mucosa is stripped and drilled, the space is obliterated with gelatin foam, and the mucosal graft is used on the posterior maxillary wall.

In closure, Gelfoam (Pfizer, N.Y.) is placed in the lateral sphenoid recess, and the inferior turbinate mucosa is returned with three to four sutures (5/0 Vicryl-Rapide, Ethicon, N.J.). The septum is covered with two 0.5-mm silastic sheets (Medtronic, Fla.) and secured with suture (4/0 Prolene, Ethicon, N.J.). The middle meatus is stented with either absorbable or nonabsorbable material. In all cases, image guidance was not used. The entire operation is performed with a 0° endoscope and straight instruments, including bipolar cautery.

Post-Operative Care

Patients were kept in hospital for neuromonitoring following surgery for two to five days. Amoxicillin/clavulanic acid was given for 10 days, and prednisone was given at 25 mg daily for seven to 14 days to reduce congestion and swelling. Nasal saline irrigations were commenced on discharge and delivered as 240 mL twice daily. Patients were followed up at three weeks post-operatively for removal of the silastic sheets and again at three months for review of the neosinus cavity.

RESULTS

Six patients (41.5 ± 9 years, 50% female) were assessed. Follow-up was 50.1 ± 25.2  months. All patients had defects lateral to the V2 nerve and were successfully treated using the PTMA without the need for revision surgery. Five out of six patients had left-sided pathology. Two patients (33%) had previous surgery at another institution and presented with ongoing CSF rhinorrhoea; one was revision surgery for ongoing CSF rhinorrhoea with a defect in the lateral sphenoid recess, and one patient had a left-sided encephalocele in the lateral sphenoid recess. No patient had a lumbar drain inserted during the recovery period.

Two patients (33%) reported temporary paraesthesia along/in the V2 distribution, which resolved after 90 days. No other early or late morbidities were seen.