Background: Soft tissue dissection in pterional craniotomies is done in several different techniques, mostly depending on surgeon's training and preference. When the standard pterional craniotomy was first described, interfacial dissection was recommended to preserve nerve to frontalis function and decrease muscle atrophy. Nowadays, the interfacial dissection and the myocutaneous flap are popular techniques for dissection. The subfascial technique is used by many surgeons who believe that the neurovascular structures in the temporal area are preserved by avoiding the opening of the fascia and keeping these structures intact and retracted away during surgery. In this study, we describe the subfascial dissection technique and aim to measure the pros and cons of this approach subjectively and objectively on functional, radiological, and esthetic outcomes
Methods: This is a prospective cohort. Subfascial dissection was performed by a single surgeon on patients undergoing elective first time craniotomy between the period of 2018 to 2020. The dissection begins with the skin incision that is done in a standard curvilinear fashion for the pterional approach exposure in all cases, starting 1 cm anterior to the tragus and curved behind the hair line towards the midline. The skin is reflected with the pericranium flap and the temporalis fascia anteriorly. The exposed temporalis muscle was separated from the superior temporal line and reflected inferiorly. The superior orbital rim is exposed as well as part of the frontal process of the zygomatic bone and the zygomatic arch. Patient clinical and radiological data were collected preoperatively and in 4 points of time postoperatively.
Results: Out of the 20 patients, there were 13 females and 7 males, with mean age of 45 years. The pathology was meningioma in 80 % of patients (16 patients), while the other 20% had low- and high-grade gliomas. The time consumed from skin incision to the first burr hole ranged from 15-30 minutes in most patients, and closure from the last bone screw to the first skin suture ranged from 30 to 45 minutes regardless of the primary surgeon's level. Regarding frontalis muscle dysfunction, 11% showed zero movement upon discharge, with 72% full recovery by one month, 83% full recovery by 6 months and 100% recovery by one year. Temporalis muscle thickness was averaged to be 8.5 mm preoperatively and 7.1 mm 6 months operatively with 1.5 mm (-17.4%) average atrophy. 55% of patients experienced mild tenderness immediately postoperatively with complete resolution of tenderness after one month. 43% of patents reported mild to moderate pain during talking and mastication immediately postoperatively, with 88% complete resolution of the pain by 6 months. 66% of patients were extremely satisfied with the cosmetic outcome postoperatively.
Conclusion: Subfascial dissection is a straightforward technique with few steps to facilitate soft tissue dissection in pterional craniotomies and its variants. It consumes less time in the operative room and ensures that the important neurovascular structures are tucked away between temporalis fascia layers. It provides fair functional outcome and less pain but may cause significant muscle atrophy and scaring.