April 2020 HSC Section 4 - Plastic and Reconstructive Problems

Current Management of Subcondylar Fractures

incision. Scho¨ n and colleagues 9 performed a series of open repairs on 17 patients, 8 of whom were treated with an endoscopic transoral approach. He showed that the transoral approach was a reliable form of treatment of subcondylar fractures and that, once trained in this technically challenging approach, it can be much faster than an open approach. The surgery begins by placing arch bars and putt- ing patients in MMF. The mucosa overlying the ramus in infiltrated with lidocaine with epinephrine. An incision is made over the anterior border of the ramus and extended to the oblique line. The peri- osteum and masseter are then elevated over the lateral surface of the mandible from the angle to the condylar neck. Keeping the periosteum intact decreases bleeding and improves visualization. Once a pocket is created, the endoscope is intro- duced. A 4-mm, 30 rigid telescope is used through a brow lift sheath. Elevation is continued until the fracture site is encountered. Care is taken to elevate along the lateral border of the proximal segment. Furthermore, to facilitate downward traction on the mandible, a stab incision parallel to the facial nerve is made and a trocar is placed at the angle. A self-tapping, self-drilling screw is placed in the bone and a wire is twisted around the screw to help manipulate the distal segment. 10 An alterna- tive is creating a small submandibular incision and placing a drill hole. A 24-gauge wire may be threaded through the hole to use for manipulation when attempting reduction. 11 Once there is adequate visualization, the frac- ture is ready to be reduced. Patients need to be released from MMF to accomplish this. Down- ward traction is applied to the distal segment by either pushing downward on the mandibular teeth or using one of the previously described methods. A bite block may be placed between the ipsilateral molar dentition while attempting to place the anterior dentition in occlusion. This placement will lengthen the ramus and aid in reduction. Medially displaced fractures can be more difficult to reduce, and it may be necessary to move the proximal segment laterally first. A transbuccal stab incision is placed, and a trocar is introduced. Once the fragment is lateralized, instruments introduced through the trocar may be used to help reduce the fracture. A second stab incision may be placed, and a threaded fragment manipulator may be secured to the proximal segment for better control of the frag- ment if necessary. However, if this is used, great ENDOSCOPIC SURGICAL TECHNIQUE

care must be taken not to fracture the screw portion of the device. When possible, 2-plate fixation has been advised because of the risk of bony fracture displacement and/or plate fracture. 12 If only one plate is possible because of patient anatomy and fracture characteristics, elastic MMF may be required postoperatively to offset some of the dy- namic force on the plate. Typically, 2-0 zygomatic plates are used with a goal of 2 holes placed on either side of the fracture ( Fig. 1 ). Resorbable plates have been discussed; however, they have not proven to be strong enough to withstand the occlusal loading of the condyle and there is a risk of refracture. 4,12 There may be a role for their use in combination with elastic MMF, but data are limited. 4 Postoperatively, patients may require elastic MMF until the natural occlusion is restored. Rigid fixation is typically not required. A soft diet is advised for 4 to 6 weeks. Physical therapy is often indicated, particularly when there is concern for temporomandibular joint arthroses or malocclu- sion. The need for postoperative imaging is not clearly defined. The authors prefer to obtain a cor- onal CT scan to ensure the condylar fragment is reduced into the glenoid fossa. Facial nerve injury is possible with transoral endo- scopic repair but, in theory, should be much less of a risk than with open repair. No facial nerve injury was reported in several studies. 2,3,10,12,13 Lee and colleagues 14 reported a single temporary facial nerve injury that fully recovered, and Kang and colleagues 12 reported 3 temporary facial palsies that improved over time. These findings COMPLICATIONS

Fig. 1. Endoscopic placement of final screw in the distal segment of a subcondylar fracture.

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