PURPOSE A cornerstone of the treatment of maxillofacial trauma and craniomaxillofacial surgery is the establishment of proper dental occlusion with maxillomandibular fixation. The use of bicortical (IMF) screws offers some distinct advantages over more traditional arch bar fixation. Advantages include reduced operative time, decreased risk of sharp injury to operating personnel, and screw removal in the office setting. In addition, IMF screws may allow for better oral hygiene and decrease the risk of trauma to the gingiva leading to overall improved oral health during the period of maxillomandibular fixation. However, the use of IMF screws is not without risk. Risks include iatrogenic injury to tooth roots and local nerves as a result of improper placement. Additional complications include fracture of the screw and screw loosening. Limited data exist to compare indications, complications and outcomes between traditional methods of IMF and IMF screw fixation.

METHOD A survey tool was created to evaluate practice patterns in the treatment of adult mandible fractures. Questions assessed indications for and frequency of use of IMF screws and arch bars. Complications resulting from the use of IMF screws and arch bars were also probed. In addition, we assessed time for application, history of needlestick/sharp injury, setting for removal of IMF and method used to prevent dental complications. The survey was given to attending plastic surgeons and ENT surgeons who treat maxillofacial trauma in our institution.

RESULTS A total of 9 surgeons participated in the study. 6 surgeons used IMF screws primarily while 2 surgeons used arch bars preferentially. 6 surgeons frequently used IMF screws for mandible fractures in any location, 5 surgeons frequently used IMF screws on comminuted fractures although always with ORIF. Complications related to the use of IMF screws included tooth root damage (3/9), loosened screws (7/9), broken screws (4/9), loss of imf (3/9). 5 of 9 surgeons reported rare instances of malocclusion and nonunion. No surgeon reported nerve damage associated with the use of IMF screws. Complications related to arch bars included loose teeth (2/9), loose arch bars (7/9), gingival injury (6/9), loss of imf (3/9), malocclusion (4/9) and mal/nonunion (5/9). IMF screws averaged 22 minutes to apply, whereas arch bar application averaged 44 minutes. 8 of 9 surgeons removed mandibular hardware in the operating room regardless of type. 8 of 9 surgeons used physical exam to safely place IMF screws while 2 of 9 emphasized tactile feedback to avoid damaging tooth roots. All surgeons in this study had experienced a sharps injury related to arch bar placement.

CONCLUSION The widespread introduction of IMF screws since the 1990s has provided and alternative to arch bars for providing maxillomandibular fixation. This survey supports the conclusions of prior work suggesting that IMF screws are faster to apply and have a lower risk of sharps injury. Interestingly only 1 of the 9 surgeons in the study removes the IMF screws in the office setting. There appears to be no difference in rates of loss of IMF, malocclusion or mal/nonunion dependent on method of fixation. Surgeons in this study use IMF screws for all locations of mandible fractures, usually in combination with ORIF. There were a significant number of surgeons reporting rare tooth root injuries and screw breakages in the IMF screw group compared with a small number of tooth loosening with arch bars. Careful attention to placement of screws and repositioning if increased torque is required should help to avoid injury to the teeth. Further outcome studies would evaluate the safety and efficacy of IMF screws compared with more traditional arch bars.