Rhinology, Sinus and Skull Base Disorders

Simplifying the Transpterygoid Approach to Lateral Sphenoid Meningoencephaloceles: A Shorter Run for a Longer Slide

Cerebrospinal fluid (CSF) leaks and meningoencephaloceles originating in the lateral recess of the sphenoid sinus can be challenging to manage. The traditional “direct line” transpterygoid approach through the pterygopalatine fossa (PPF) is technically demanding, time consuming, and risks injury to important structures, which can result in significant morbidity including dry eye, dry nose, and facial numbness. The skull base team at Cleveland Clinic has developed a modified transpterygoid approach (MTPA) to access the lateral sphenoid sinus, which completely avoids dissection of the PPF contents.¹ This innovative technique was founded on the notion that endoscopic surgeons now have greater facility with angled endoscopes, and it leverages advances in angled and malleable instrumentation that allow for surgeons to more effectively “operate around corners.” In the MTPA, the face of the sphenoid and anterior junction of the pterygoid plates are removed, allowing for mobilization of the PPF contents with the periosteum intact. Angled instrumentation is then used to resect the meningoencephalocele and repair the skull base defect in the lateral recess.

The skull base team recently published the findings of a multiinstitutional study using this novel technique.2 Patients with lateral sphenoid recess CSF leaks and meningoencephaloceles between 2014 and 2020 who underwent the MTPA at 2 academic medical centers were identified. Repair techniques and outcomes were evaluated.

CharacteristicsPatient Number
Age, mean (SD)53 ± 13.6
Male3 (9.1%)
Female30 (90.9%)
Body mass index, mean (SD)39.5 ± 9.4
Laterality of skull base defect (%)
Right14 (42.4%)
Left19 (57.6%)
Meningoencephalocele on imaging (%)
Present23 (69.7%)
Absent10 (30.3%)

Thirty‐three patients underwent the MTPA for management of lateral sphenoid sinus meningoencephaloceles. Skull base reconstruction was performed using a free mucosal graft (24/33, 72.7%), nasoseptal flap (4/33, 12.1%), bone grafts (3/33, 9.1%), and abdominal fat grafts (2/33, 6.1%). Lumbar drains and perioperative intracranial pressure measurements were routinely employed.

CharacteristicsPatient Number
Method of skull base repair (%)
Free mucosal graft24 (72.7%)
Nasoseptal flap4 (12.1%)
Bone graft3 (9.1%)
Abdominal fat2 (6.1%)
CSF pressure measurement, mean (SD)
Intraoperative20.1 ± 5.7
Postoperative (day 3)22.1 ± 7.7
History of meningitis preoperatively (%)
No27 (81.8%)
Yes6 (18.2%)

CSF = cerebrospinal fluid

Postoperative complications were uncommon and included 3 patients (9.7%) with temporary maxillary nerve (V2) anesthesia, 1 patient (3.2%) with prolonged V2 anesthesia, and 1 patient (3.2%) with subjective dry eye, all of which resolved at 9 months postoperatively. There were no recurrent CSF leaks, resulting in a 100% success rate. Average follow‐up was 13 months.

Postoperative OutcomesPatient Number
CSF leak repair (%)
Success33 (100%)
Failure0 (0%)
Postoperative complications (%)
Short‐term (< 6 months) V2 anesthesia3 (9.7%)
Long‐term (> 6 months) V2 anesthesia1 (3.2%)
Subjective dry eye1 (3.2%)
Postoperative hemorrhage0 (0%)
V2‐related neuropathic pain0 (0%)
Recurrent CSF leak0 (0%)

CSF = cerebrospinal fluid, V2 = maxillary nerve

The study demonstrated that the MTPA reduces morbidity and greatly simplifies access to the lateral sphenoid sinus for the management of CSF leaks and meningoencephaloceles, without compromising exposure. This technique avoids the need for extensive PPF dissection and should be considered for the management of benign lesions involving the lateral sphenoid sinus.

References
  1. Sreenath SB, Tang DM, Almeida JP, Soni P, Woodard TD, Recinos PF, Kshettry VR, Sindwani R. Simplifying Access to the Lateral Sphenoid Recess: A Modification of the Transpterygoid Approach. Am J Rhinol Allergy. 2021 Mar 24. doi: 10.1177/19458924211003813. Online ahead of print.

  2. Sreenath SB, Tang DM, Ting JY, Illing EA, Recinos PF, Soni P, Kshettry VR, Cohen-Gadol A, Woodard TD, Sindwani R. Modified Transpterygoid Approach to Sphenoid Meningoencephaloceles: A Shorter Run for a Longer Slide. Laryngoscope. 2021 Oct;131(10):2224-2230. Epub 2021 Jun 7.