Suprafascial dissection for pterional craniotomy to preserve the frontotemporal branch of the facial nerve with less temporal hollowing

Background: To protect the frontotemporal branch of the facial nerve (FTFN) when performing pterional craniotomy, several reports suggest the subfascial or interfascial dissection technique. However, the reports of postoperative frontalis paralysis and temporal hollowing, which are common complications, were relatively limited. This study reports the incidence of postoperative frontalis paralysis and temporal hollowing after pterional craniotomy using the suprafascial and interfascial techniques. Methods: Patients who underwent pterional craniotomy, using the suprafascial technique (leaving the muscle cuff and not leaving the muscle cuff) and the interfascial technique, between November 2015 and September 2018 were retrospectively evaluated for postoperative frontalis paralysis and temporal hollowing using Chi-squared/ Fisher exact test. Results: Seventy-two patients underwent pterional craniotomy, using the suprafascial technique in 54 patients (leaving the muscle cuff in 21 patients and not leaving the muscle cuff in 33 patients) and the interfascial technique in 18 patients. Eleven patients (20.4%) in the suprafascial group and 1 patient (5.6%) in the interfascial group developed transient frontalis paralysis (P = 0.272). No permanent frontalis paralysis was observed. Obvious temporal hollowing occurred in 18.2% of patients in the suprafascial group without the muscle cuff, in 64.3% of patients in the suprafascial group with the muscle cuff, and in 72.7% of patients in the interfascial group (P = 0.003). Conclusion: The suprafascial dissection technique does not cause permanent injury of the FTFN, and this approach results in a significantly lower incidence of postoperative temporal hollowing than interfascial dissection, especially without leaving a temporalis muscle cuff.

The Ultimate Skull Base Maneuver Does Not Involve Removing Bone: Quantifying the Benefits of the Interfascial Dissection

Introduction Several adjunctive osteal skull base maneuvers have been proposed to increase surgical exposure of the anterolateral approach. However, one of the easiest methods does not involve bone: the interfascial temporalis muscle dissection. Methods Sequential dissections were performed bilaterally on five fixed silicone-injected cadaver heads. The amount of sphenoid drilling, scalp retraction, and brain retraction was standardized in all specimens. For each approach, surgical angles were measured for four deep targets: the tip of the anterior clinoid process, the internal carotid artery terminus, the origin of the posterior communicating artery, and the anterior communicating artery. Five surgical angles were measured for each target. Results There were increases on the order of 20% in the anteroposterior (AP)-mid, AP–lateral, and mediolateral–anterior angles for all deep targets with interfascial approach versus a myocutaneous flap. An orbitozygomatic osteotomy additionally increased almost all the angles, but incrementally less so. Conclusion An interfascial dissection increases the surgical exposure to a larger degree than additional osteotomies for several surgically relevant working angles. The addition of an orbitozygomatic osteotomy affords a particular benefit for the suprachiasmatic region. Increased adoption of interfascial mobilization or the temporalis muscle—an easily performed and low-risk maneuver—during anterolateral craniotomies may obviate the need for more involved skull base drilling.

Microsurgical Anatomy of the Interfascial Vein. Its Significance in the Interfascial Dissection of the Pterional Approach

BACKGROUND: The pterional approach (PA), together with its variants, is still one of the most common methods used by surgeons to reach the anterior and middle cranial base. A highly important technical detail during a PA is the preservation of the frontotemporal branch of the facial nerve, which can be achieved through an interfascial dissection. OBJECTIVE: To describe the anatomy of the interfascial vein (IFV), highlighting its recognition as a significant anatomic reference to perform an interfascial dissection (IFD). METHODS: Eight adult cadaveric heads, fixed with formaldehyde and injected with colored silicone, were studied. In 6 heads, an IFD was performed, simulating a PA. In the 2 remaining heads, the IFV was dissected. In addition, an IFD was performed in 10 patients, studying the IFV anatomy. RESULTS: In the 6 cadaveric heads in which the PA with an IFD was performed, and in the 10 patients who underwent a PA with an IFD, the IFV was found. If the interfascial space is divided into thirds, in all cases, the IFV was located within the middle third of the interfascial fat pad. On the 2 cadaveric heads in which the IFV was anatomically dissected, the IFV was also located within the middle third of the interfascial space. CONCLUSION: Recognizing the IFV in the interfascial space is of great help as an anatomic landmark to confirm that one is actually between both layers of the superficial temporal fascia.