Prevention of the trigeminal nerve’s third branch injuries during the sagittal osteotomy of the mandible

Background. Treatment of patients with skeletal forms of occlusion anomalies is a current problem of maxillofacial surgery. The most common method of surgical treatment is sagittal planar osteotomy of the mandible by Obwegeser-Dal Pont. The technique of this surgery presumes the osteotomy lining in the close vicinity of the mandibular canal, which implies a high risk of various injuries of the inferior alveolar nerve.

Aim: Development of a surgical pattern for sagittal mandible osteotomy and prevention of the inferior alveolar nerve injury.

Material and methods. Within the framework of the study, 14 patients of 18–30 years old with congenital anomalies of jaws were operated. According to the nosological forms, the patients were distributed as follows: 5 patients diagnosed with mandibular retro- and micrognatia, distal occlusion, skeletal type, Angle II class and 9 patients diagnosed with mandibular macrognatia, maxillary retro-and micrognatia, mesial occlusion, skeletal type, III class on Engle. Surgical treatment planning started with the evaluation of the face configuration (smile line, height of the upper, middle and lower third of the face, the height of the upper and lower lips, the red border), the amplitude of opening the mouth, the displacement of the mandible when opening the mouth, the presence or absence of clicks or crackles in the mandibular joint; the deviation from the central line of the upper and lower jaws; height and position of tooth crowns, depth of incisal overlap; interdental space; width of the sagittal slit. Clinical photography was obligatory for all patients. The next mandatory stage of the examination was radiography: all patients underwent a cone-beam computed tomography of the entire head on a 3-DX ACCUITOMO 3D computer tomograph (FIRM Morita, Japan). Then the analysis of computer tomography data was carried out in the software complex ViSurgery (LLC «New Technologies in Surgery», Moscow). Pattern and mandible models were printed on the 3D printer DesignerPro (Picaso 3D, Russia).

Results. The postoperative period proceeded without inflammatory complications in all operated patients. The orthognathic ratio of the dentition was achieved. 100% of patients in the early postoperative period revealed a slight loss of tactile sensitivity in the chin and mouth angle from both sides. Sensitivity was fully restored in 60% of patients by the 5-7th day after surgery, in 25% of cases – by the 14th day and in 15% by the 30th day, respectively. The sensitivity restoration period was increased in patients with retromicrognatia of mandible, which was associated with the extension of the nerve trunk, due to the displacement of the tooth-containing fragment of the jaw.

Conclusion. Intraoperative use of the proposed resection surgical template design allows to reduce the frequency of the inferior alveolar nerve trunk damage and to exclude its intersection during sagittal osteotomy of mandible. Key words: inferior alveolar nerve, osteotomy, orthognathic surgery, bite anomaly, surgical pattern.

Authors declare no conflict of interests for this article.

Source of financing. Unspecified.

For citations: Musaeva E.M., Ivanov S.Yu., Murayev A.A., Gusarov A.M. Prevention of the Trigeminal Nerve’s Third Branch Injuries During The Sagittal Osteotomy Of The Mandible. Golova I Sheya = Head and neck. Russian Journal. 2018;6(1):18–22 (in Russian).