Nerve injury associated with orthognathic surgery. Part 1: UK practice and motor nerve injuries.

The head and neck is anatomically complex, and several nerves are at risk during orthognathic operations. Some injuries to nerves are reported more commonly than others. To find out what consultant surgeons tell their patients about the prevalence of common nerve injuries before orthognathic operations, we did a postal survey of fellows of the British Association of Oral and Maxillofacial Surgeons (BAOMS). We also reviewed published papers to find out the reported incidence of injuries to cranial motor nerves during orthognathic operations. Only injuries to the facial nerve were commonly reported, and we found only case reports about injuries to the oculomotor, abducens, and trochlear nerves. The risk of temporary facial nerve palsy reported was 0.30/100 nerves (95% CI 0.23 to 0.50) and permanent facial nerve palsy was 0.06/100 nerves (95% CI 0.02 to 0.15).

Nerve injury associated with orthognathic surgery. Part 2: inferior alveolar nerve.

The inferior alveolar nerve (IAN) is the most commonly injured structure during mandibular osteotomies. The prevalence of temporary injury has been reported as 70/100 patients (95% CI 67 to 73/100) or 56/100 nerves (95% CI 46 to 65/100), and the prevalence of permanent alteration in sensation was 33/100 patients (95% CI 30 to 35/100) or 20/100 nerves (95% CI 18 to 21/100) when assessed subjectively. The prevalence varied significantly between different operations (p<0.0001). It was significantly higher for sagittal split osteotomy (SSO) combined with genioplasty than for SSO alone (p<0.0001) or vertical ramus osteotomy (VRO) (p<0.0001). Injury may result from traction during stripping or manipulation of the distal fragment, incorrect placement of the cuts, or misjudged placement of fixation in ramus ostotomy. During SSO, they can occur during retraction to make cuts in the medial ramus, when the bone is cut or split, and on fixation. The impact of injury is generally said to be low as it does not seem to affect patients' opinions about the operation.

Nerve injury associated with orthognathic surgery. Part 3: lingual, infraorbital, and optic nerves.

In the final paper of this 3-part series we review the incidence of injuries to the lingual, infraorbital, and optic nerves during orthognathic operations. We know of few published studies on the incidence of injuries to the lingual or infraorbital nerves, but in most cases they are thought to result from traction and are predominantly temporary. The incidence of permanent injury to the lingual nerve was 2/100 patients (95% CI 1 to 3/100) or 0/100 nerves (95% CI 0 to 1/100). The methods used to assess injury to the infraorbital nerve differed so it was not possible to calculate the incidence. Injuries to the optic nerve, although rare, have a considerable impact on the patients affected.