Introduction: Trismus after neurosurgical procedures is an unusual complication.

Case report: In the postoperative recovery of temporal bone craniotomy for treatment of intracranial AV malformation the patient developed a progressive trismus that limited the mouth opening to 14 mm. With physiotherapy it arrived to 22 mm. MRI and CT showed a normal TMJ. Coronoidectomy and temporal muscle detachment was performed and an intraoperative opening of 34 mm was achieved. After postoperative physiotherapy we reached 39 mm.

Conclusions: Mouth opening limitation may be due to extraarticular reasons such as fibrous scars of the temporal muscles. This cases may be solved with simple coronoidectomy.