Complications in Endoscopic Skull Base Surgery

Minor Complications in Skull Base Surgery

Endonasal surgery uses the sinonasal corridors to access the skull base. Access through the nasal cavity allows for a minimally invasive approach, but it also comes with an associated cost to the normal function of the sinonasal cavity.

Postoperative sinusitis and synechia formation are perhaps the most common minor complications from endonasal skull base surgery. After a comprehensive disruption of the normal sinonasal anatomy, some degree of postoperative crusting develops in many patients. This crusting is frequently debrided in the clinic to prevent sinusitis and synechia formation. A literature review of skull base sinonasal outcomes demonstrated a 50% incidence of significant postoperative crusting, with 40% of patients demonstrating sinusitis symptoms of nasal drainage and obstructive symptoms. Although these symptoms can be relatively benign, they can significantly affect quality of life. Synechia formation after endonasal sinus surgery has been reported in 5% to 28% of patients, and results from skull base surgery would presumably be similar. Notably, delayed mucocele formation can occur when a sinus becomes obstructed from scarring of the outflow tract postoperatively and has been reported in 3% to 8% of cases.

Postoperative epistaxis is a relatively common consideration after endoscopic sinonasal surgery. And although most postoperative epistaxis is mild, severe hemorrhage requiring operative control is well defined and typically stems from an arterial source. Classically nasal epistaxis can be managed with nasal packing; however, in the fresh postoperative setting, particularly after a skull base resection, aggressive packing must be approached cautiously to avoid intracranial complications from improperly placed packs. Furthermore, it is worth noting that the majority of reported epistaxis events occur 2 to 4 weeks postoperatively. In a recent review, Zimmer and Andaluz reviewed more than 400 endoscopic pituitary surgeries, demonstrating a 4.1% rate of postoperative epistaxis. They noted that of the 18 patients, 11 were treated with in-office cauterization, packing, or intranasal hemostatic agents, whereas 5 required a return to the operating room and 2 required embolization. Similarly, Thompson et al. reported a 3% incidence of postoperative epistaxis in their single-institution cohort. Although the majority of episodes of epistaxis were controlled with packing, 5 of 14 events required control in the operating room. These data confirm that, overall, postoperative epistaxis is relatively uncommon after endoscopic skull base surgery and frequently can be managed with conservative measures. However, some patients require operative control, particularly in cases of arterial hemorrhage.

Nasal deformities such as saddle nose have been reported after skull base surgery. This is particularly identified after nasoseptal flap and subsequent septectomy. In one major report on these nasal deformities, the authors highlight a nearly 6% overall incidence of nasal dorsal collapse. The authors noted these deformities were associated with nasoseptal flap use (15% of patients who underwent nasoseptal flap) and highlight several potential explanations, including electrocautery, contracture scar forces, overaggressive septectomy, and postoperative radiation as potential implicating factors. Soudry et al. performed a retrospective review demonstrating a less than 1% rate of saddle deformity. Although these nasal deformities are not life threatening, they are challenging to repair and can have significant impacts on the patient’s social and functional status. We speculate that preservation of the entire septal attachments to the anterior premaxilla may help prevent this complication.

Using the sinonasal corridor for access to the skull base has several advantages, but one notable disadvantage is the potential disruption to the olfactory system. Postoperative hyposmia has been well documented and evaluated by several studies. Several technical concepts have been suggested to potentially improve olfaction outcomes, including the preservation of the septal olfactory strip and preservation of the middle turbinates when possible. Results from a variety of studies demonstrate a wide variety of results, ranging from no significant dysfunction, to temporary impairment, to significant permanent olfactory disturbance. Some studies have reported rates of long-term olfactory disturbance up to nearly 30%. A prospective study of 42 patients who underwent baseline and periodic postoperative testing (University of Pennsylvania Smell Identification Test) demonstrated that patients undergoing pituitary surgery with rescue flap elevation showed no evidence of olfactory dysfunction, whereas patients with a nasoseptal flap showed temporary dysfunction. A recent evidence-based review and recommendation on olfactory function after endonasal skull base surgery was published by Greig et al. They concluded that the body of evidence was heterogeneous, but routine transsphenoidal surgery with rescue flaps and at least one middle turbinate preserved likely leads to limited long-term olfactory dysfunction. However, they also concluded that nasoseptal flap harvest and potentially electrocautery likely lead to increased olfactory dysfunction.