Armamentarium

History of the Procedure

Comminuted mandibular fractures occur when an excessive amount of force, and associated energy transfer, occurs to the osseous structures of the mandible. Frequently caused today by motor vehicle accidents or striking a rigid, nonmoveable structure, these fractures have been seen in Europe since the introduction of gunpowder and ballistic projectiles to warfare in the fourteenth century. The historical treatment of comminuted mandibular fractures focused on the principle of closed management, used primarily to avoid stripping the periosteum and subsequent blood supply from the comminuted bony segments. A variety of surgical techniques, such as maxillomandibular fixation (MMF), surgeon-fabricated occlusal splints or Gunning splints, and extraoral skeletal pins, were used, with varying degrees of success and patient outcomes. Kazanjian was the first to challenge this notion, based on his observations of maxillofacial injuries sustained in World War I. He noted, “The majority of nonunited fractures of are due to inadequate immobilization of comminuted fragments of bone, and subsequent infection, rather than to the initial loss of bone.” He believed that stabilization of the bony segments was the critical step in obtaining union and consolidation of the comminuted osseous fragments. Kazanjian’s theories subsequently led to the development of numerous techniques for maintaining the reduced fracture segments in position, eventually leading to the current modality of open reduction and rigid internal fixation with surgical plates and screws.

History of the Procedure

Comminuted mandibular fractures occur when an excessive amount of force, and associated energy transfer, occurs to the osseous structures of the mandible. Frequently caused today by motor vehicle accidents or striking a rigid, nonmoveable structure, these fractures have been seen in Europe since the introduction of gunpowder and ballistic projectiles to warfare in the fourteenth century. The historical treatment of comminuted mandibular fractures focused on the principle of closed management, used primarily to avoid stripping the periosteum and subsequent blood supply from the comminuted bony segments. A variety of surgical techniques, such as maxillomandibular fixation (MMF), surgeon-fabricated occlusal splints or Gunning splints, and extraoral skeletal pins, were used, with varying degrees of success and patient outcomes. Kazanjian was the first to challenge this notion, based on his observations of maxillofacial injuries sustained in World War I. He noted, “The majority of nonunited fractures of are due to inadequate immobilization of comminuted fragments of bone, and subsequent infection, rather than to the initial loss of bone.” He believed that stabilization of the bony segments was the critical step in obtaining union and consolidation of the comminuted osseous fragments. Kazanjian’s theories subsequently led to the development of numerous techniques for maintaining the reduced fracture segments in position, eventually leading to the current modality of open reduction and rigid internal fixation with surgical plates and screws.

Indications for the Use of the Procedure

For craniomaxillofacial trauma surgeons, the current clinical presentation of comminuted mandibular fractures occurs secondary to a significant energy transfer to a localized region of the mandible, usually as the result of a motor vehicle accident, striking or being struck by an immoveable object, or a gunshot wound. As noted by Alpert et al, approximately 5% to 7% of all mandibular fractures present with comminution; therefore, the craniomaxillofacial trauma surgeon must be knowledgeable about the proper management of these conditions. The overwhelming majority of gunshot wounds encountered in the civilian trauma setting are caused by low-velocity, low–energy transfer handguns and do not display the characteristic soft tissue changes seen in modern high-velocity/ultra-high-velocity ballistic injuries sustained in military conflicts ( Figure 69-1 ). These injuries can produce debilitating soft tissue avulsions, sequential necrosis, and loss of tissue over the course of several days after injury, which complicate both the short-term and long-term management of these patients. The closest civilian corollary to these injuries is seen in patients who have attempted suicide, or been shot at close range (Sherman-Parrish class III), with a shotgun ( Figure 69-2 ).

A, Typical clinical appearance of low velocity–low energy gunshot wound to the mandible. Note the lack of significant soft tissue injury. B, Three-dimensional reconstruction of the CT scan of the same patient. Note the localized area of comminution associated with this injury. C, Typical clinical appearance of a high velocity–high energy ballistic wound to the mandible and associated significant soft tissue injury. D, Characteristic degree of comminution associated with a high-energy ballistic wound to the mandible.

( A from Powers DB, Delo RI: Maxillofacial ballistic and missile injuries. In Fonseca RJ et al, editors: Maxillofacial trauma, St Louis, 2012, Mosby.)

Clinical appearance of a patient who attempted suicide with a shotgun. Note the massive hard and soft tissue loss associated with this injury.

(From Powers DB, Delo RI: Maxillofacial ballistic and missile injuries. In Fonseca RJ et al, editors: Maxillofacial trauma, St Louis, 2012, Mosby.)

Limitations and Contraindications

Avulsive tissue loss, with resultant exposure of any underlying surgical hardware, is an obvious limitation in the management of comminuted fractures. Definitive plans for reconstruction of the osseous skeleton must be coordinated with concurrent planning for recruitment of soft tissue to the site of tissue avulsion. If rigid internal fixation is the preferred management technique for a comminuted fracture, the fragmented portions of the mandible cannot be subjected to masticatory functional loads. The surgeon must adhere to two basic tenets of treatment. First, the fixation must support the entire functional load (i.e., the principle of load-bearing osteosynthesis). The selected surgical plate must be of a sufficient size and strength to withstand the functional forces applied to it. Second, absolute stability of the reconstruction construct must be achieved. In comminuted fractures, the small bone fragments cannot take part of the functional load, as is seen in load-sharing osteosynthesis, nor can they be compressed due to risks of sequestration and devitalization.

Technique: Surgical Treatment of the Comminuted Mandibular Fracture