Pseudoankylosis of the mandible after supratentorial craniotomy.

After temporal craniotomy, pseudoankylosis of the mandible can cause difficult airway management during subsequent anesthesia. However, postcraniotomy changes in maximal mouth opening and the incidence of limited mouth opening have not been characterized. Ninety-two adult patients who underwent elective craniotomy were divided into three groups: Group A (n = 28) included patients who underwent parietal, occipital, or frontal craniotomy without incision of the temporalis muscles; Group B (n = 25) included patients who underwent temporal craniotomy; and Group C (n = 39) included patients who underwent frontotemporal craniotomy. Maximal mouth opening (interincisor gap) and the frequency of limited mouth opening (maximum mouth opening < or = 2.5 cm) were evaluated before operation and 3 days, 1 wk, 2 wk, 1 mo, and 3 mo after operation. The three groups did not differ with respect to age, sex, body weight, height, operative time, anesthetic time, or maximum mouth opening before operation. The postoperative reduction in maximal mouth opening was significantly greater in Group C than in Group B. In Group C, the incidence of limited mouth opening was 33.3% and 20.5% 2 wk and 1 mo after operation, respectively; however, limited mouth opening resolved within 3 mo in most patients. Supratentorial craniotomies separated by short intervals can increase the risk of limiting the mandibular opening, which may result in a difficult intubation. Careful preoperative assessment of the airway is mandatory if patients have previously undergone temporal or frontotemporal craniotomy.