Precision Splitting of the Temporalis Muscle Flap for Postradiation Skull Base Osteoradionecrosis: A Prospective and Single-Arm Clinical Study.

Abstract

Background: Temporalis muscle flap (TMF) reconstruction is common for postradiation skull base osteoradionecrosis (ORN). However, the whole TMF may be too large, causing difficult tunnel passage, tearing, and choanal atresia, while an overly small TMF risks pedicle damage and incomplete coverage. Safely harvesting an appropriate TMF remains challenging. We evaluated the feasibility and long-term outcome of precise TMF splitting and explored necrosis risk factors.

Study design: Prospective, single-arm clinical study.

Setting: Comparison of inter-group ultrasonographic parameters of the anterior/posterior deep temporal arteries (ADTA/PDTA), analyzed flap survival rate, risk factors for flap necrosis.

Methods: Sixty ORN patients who underwent TMF reconstruction were included. Preoperative ultrasonography mapped ADTA/PDTA to guide TMF splitting. Surgical outcomes and complications were recorded. Univariate analysis and multivariate Firth's penalized logistic regression were used to identify independent risk factors for flap necrosis.

Results: Overall flap survival rate was 95.00% (57/60). Univariate analysis identified prolonged operative time (p = 0.006), tumor recurrence (p = 0.049), and low preoperative prealbumin (p = 0.033) as risk factors. Multivariate analysis confirmed operative time as an independent risk factor (OR = 1.007, p = 0.035). The optimal operative time cutoff for predicting necrosis was 635 min (AUC = 0.824, p = 0.032), which is presented as an exploratory threshold requiring validation in future cohorts.

Conclusions: Precise TMF harvesting is suitable for predominantly unilateral nasopharyngeal reconstruction, especially for necrosis invading the internal carotid artery, avoiding complications such as temporal depression, choanal atresia/stenosis from an oversized flap, and necrosis from difficult tunnel passage.

Level of evidence: 3: