Trauma and reconstructivesurgery
R gid !nternal fixation of mandibular fractures
Tateyuki lizuka, Christian Lindqvist Department of Oral and Maxiliofacial Surgery, IV Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland
An analysis of 270 fractures treated using the A0/ASIF method T. Iizuka, C. Lindqvist: Rigid internal fixation of mandibular fractures. An analysis of 27Ofractures treated using the AO/ASIF method. Int. J. Oral Maxillofac. Surg. 1992; 21: 65-69. Abstract. The results are reported on 214 patients treated for 270 mandibular fractures, using rigid internal fixation. Of these, 172 fractures (63.7%) in 131 patients had been re-evaluated at final follow-up in connection with plate and screw removal, on average 15.2 months, postoperatively. Although one-third of the patients had a history of alcohol abuse, and 86% were treated with a delay of more than 24 h (mean 3.2 days), good primary bone healing was observed in 93.9% of the patients. Infections, seen in 6.1% of the patients, were related exclusively to inadequate stability of the fracture. Malocclusion, observed in 18.2% of 159 dentate patients, was caused by incorrect plate bending and insufficient fracture reduction. Immediate postoperative dysfunction of the inferior alveolar nerve in 58.1% of the cases, and of the mandibular branch of the facial nerve in 12.7%, was followed by almost total recovery 1 year after operation. It is concluded that rigid internal fixation is a reliable method of treatment, especially indicated for patients with reduced healing capacity and poor co-operation.
Fractures of the mandible are generally treated by closed or open reduction4'21. Open reduction, involving internal fixation, is used in displaced fractures. Common methods of fracture fixation include the use of wires, pins or plates, and screws. Sufficient stability of the fracture is always necessary for bone healing. If internal fixation does not result in rigid stability at the fracture, some form of supplementary fixation may be necessary. Traditional methods involve additional intermaxillary fixation (IMF), using arch bars and splints. There are, however, several disadvantages associated with IMF, including: compromised airway, poor oral hygiene, speech difficulties, impaired nutritional intake with weight loss, and disuse atrophy of the masticatory muscles. Problems in relation to I M F in patients with multiple injuries or with generalized disease, such as diabetes, alcoholism and epilepsy are well known. In recent years, rigid internal fixation allowing immediate mobilization of the mandible has won increasing acceptance as a method for treatment of man-
dibular fractures 2,16,18-2°,22,26. In our department the A O / A S I F (AO Study Group for Internal Fixation) technique of rigid internal fixation24 was introduced in 1983. Up to the end of 1989, 270 mandibular fractures in 241 patients had been treated with this method. In the same period 1,823 patients with fractures of the mandible were seen. The annual percentages of open reduction and osteosynthesis varied between 18% and 29% (mean 25%). In general, open surgery was used in fractures with displacement and/or instability of the horizontal part of the mandible. Nondisplaced fractures and condylar fractures were usually treated by I M F alone. Helsinki University Central Hospital serves the 1.5 million inhabitants of the greater Helsinki area and the southern part of Finland. The object of this paper is to report the results of an analysis on the treatment of mandibular fractures using rigid internal fixation with the A O / A S I F plates. Special attention was paid to the technical problems which could affect the number of complications and out-
Key words: trauma; mandibular fracture; rigid fixation. Accepted for publication 14 January 1992
come of treatment and to factors related to patients' general health and drug habits.
Material and methods Patients with mandibular fractures treated following the AO/ASIF principle of rigid internal fixation at the Department of OMF Surgery, Helsinki University Central Hospital, between 1983 and 1989 were reviewed. Fractures with substantial comminution and defects, usually resulting from gunshot injury, were excluded because the special characteristics of such fractures influence the analysis relating to fracture site. Sites and numbers of fractures, surgical approach, presence of a tooth in the line of fracture, and whether or not tooth extraction was undertaken were recorded. Complications were defined as infection, delayed union or non-union, malocclusion and postoperative nerve injuries (motor disturbance affecting the mandibular branch of the facial nerve and sensory disturbance affecting the inferior alveolar nerve). Fracture sites were categorized as I) symphyseal, 2) canine, 3) relating to the anterior body (in the region of the premolar teeth and the mental foramen), 4) relating to the
66
I i z u k a et al.
posterior body (in the region of the molar teeth), and 5) relating to the angular region. Associated condylar fractures were also taken into account. Postoperative follow-up examinations were performed at intervals of 1 or 2 weeks for 3 16 weeks (mean 7.1 weeks). Up until April 30, 1991, 172 fractures (63.7%) in 131 patients had been re-evaluated at final followup in connection with plate and screw removal, on average 15.2 months postoperatively (range 8 to 62 months). Twelve symphyseal fractures, 23 fractures of the canine region, 28 fractures of the anterior part of the body, 26 fractures of the posterior part of the body and 83 angular fractures were assessed. Panoramic radiographs were taken pre- and postoperatively in all cases. Surgical technique
In patients in whom the fiacture involved the tooth-bearing area of the mandible, intravenous antimicrobial therapy consisting of penicillin G (1 million IU), usually combined with metronidazole (500 mg) was administered on admission and given every 6 h preand intraoperatively. Antimicrobial therapy was continued perorally (penicillin V 1 million IU and metronidazole 500 mg evey 6 h) until the 7th day after surgery. The operation was performed under general anaesthesia with nasotracheal intubation. The occlusion was re-established by bimanual manipulation, and secured using dental arch bars and IME Fixation was reinforced, if necessary, with cold-cure acrylic resin. The fracture sites were approached transorally (58 cases) or extraorally (212 cases). The transoral approach was chosen only in cases where, in the opinion of the surgeon, sufficient reduction and stabilization of the fracture could be achieved using this approach. For the extraoral approach, a submandibular incision as described by SPmSSL24was used, taking care not to damage the mandibular branch of the facial nerve by isolating it in the superior site of the wound. A nerve detector was always used. The periosteum was elevated from the mandible, exposing the fracture line. Final fracture reduction and osteosynthesis were performed using the instruments of the Synthes ® mandibular bone plate system (Synthes, Paoli, PA, USA) and AO/ASIF technique24. The repositioning was performed using reduction forceps, usually of the compression-reduction type, fixed with ~10 mm cortical screws (o 2.7 mm) at the lower border of the mandible. An interdental wire ligature was always applied when the fracture was located within the dental arch. In angular fractures and fractures in edentulous mandibles, a tension band plate was used only in cases in which fracture reduction at the upper border of the mandible could not be achieved by use of reduction forceps. Fractures were stabilized using rigid stainless steel plates bent to fit the contour of the buccal aspect of the mandible and fixed by bicortical screws. At least 2 screws were
79 150 t
[]
INTRAORAL
IN r ~'T~AnRAI 100"
R gid !nternal fixation of mandibular fractures
Tateyuki lizuka, Christian Lindqvist Department of Oral and Maxiliofacial Surgery, IV Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland
An analysis of 270 fractures treated using the A0/ASIF method T. Iizuka, C. Lindqvist: Rigid internal fixation of mandibular fractures. An analysis of 27Ofractures treated using the AO/ASIF method. Int. J. Oral Maxillofac. Surg. 1992; 21: 65-69. Abstract. The results are reported on 214 patients treated for 270 mandibular fractures, using rigid internal fixation. Of these, 172 fractures (63.7%) in 131 patients had been re-evaluated at final follow-up in connection with plate and screw removal, on average 15.2 months, postoperatively. Although one-third of the patients had a history of alcohol abuse, and 86% were treated with a delay of more than 24 h (mean 3.2 days), good primary bone healing was observed in 93.9% of the patients. Infections, seen in 6.1% of the patients, were related exclusively to inadequate stability of the fracture. Malocclusion, observed in 18.2% of 159 dentate patients, was caused by incorrect plate bending and insufficient fracture reduction. Immediate postoperative dysfunction of the inferior alveolar nerve in 58.1% of the cases, and of the mandibular branch of the facial nerve in 12.7%, was followed by almost total recovery 1 year after operation. It is concluded that rigid internal fixation is a reliable method of treatment, especially indicated for patients with reduced healing capacity and poor co-operation.
Fractures of the mandible are generally treated by closed or open reduction4'21. Open reduction, involving internal fixation, is used in displaced fractures. Common methods of fracture fixation include the use of wires, pins or plates, and screws. Sufficient stability of the fracture is always necessary for bone healing. If internal fixation does not result in rigid stability at the fracture, some form of supplementary fixation may be necessary. Traditional methods involve additional intermaxillary fixation (IMF), using arch bars and splints. There are, however, several disadvantages associated with IMF, including: compromised airway, poor oral hygiene, speech difficulties, impaired nutritional intake with weight loss, and disuse atrophy of the masticatory muscles. Problems in relation to I M F in patients with multiple injuries or with generalized disease, such as diabetes, alcoholism and epilepsy are well known. In recent years, rigid internal fixation allowing immediate mobilization of the mandible has won increasing acceptance as a method for treatment of man-
dibular fractures 2,16,18-2°,22,26. In our department the A O / A S I F (AO Study Group for Internal Fixation) technique of rigid internal fixation24 was introduced in 1983. Up to the end of 1989, 270 mandibular fractures in 241 patients had been treated with this method. In the same period 1,823 patients with fractures of the mandible were seen. The annual percentages of open reduction and osteosynthesis varied between 18% and 29% (mean 25%). In general, open surgery was used in fractures with displacement and/or instability of the horizontal part of the mandible. Nondisplaced fractures and condylar fractures were usually treated by I M F alone. Helsinki University Central Hospital serves the 1.5 million inhabitants of the greater Helsinki area and the southern part of Finland. The object of this paper is to report the results of an analysis on the treatment of mandibular fractures using rigid internal fixation with the A O / A S I F plates. Special attention was paid to the technical problems which could affect the number of complications and out-
Key words: trauma; mandibular fracture; rigid fixation. Accepted for publication 14 January 1992
come of treatment and to factors related to patients' general health and drug habits.
Material and methods Patients with mandibular fractures treated following the AO/ASIF principle of rigid internal fixation at the Department of OMF Surgery, Helsinki University Central Hospital, between 1983 and 1989 were reviewed. Fractures with substantial comminution and defects, usually resulting from gunshot injury, were excluded because the special characteristics of such fractures influence the analysis relating to fracture site. Sites and numbers of fractures, surgical approach, presence of a tooth in the line of fracture, and whether or not tooth extraction was undertaken were recorded. Complications were defined as infection, delayed union or non-union, malocclusion and postoperative nerve injuries (motor disturbance affecting the mandibular branch of the facial nerve and sensory disturbance affecting the inferior alveolar nerve). Fracture sites were categorized as I) symphyseal, 2) canine, 3) relating to the anterior body (in the region of the premolar teeth and the mental foramen), 4) relating to the
66
I i z u k a et al.
posterior body (in the region of the molar teeth), and 5) relating to the angular region. Associated condylar fractures were also taken into account. Postoperative follow-up examinations were performed at intervals of 1 or 2 weeks for 3 16 weeks (mean 7.1 weeks). Up until April 30, 1991, 172 fractures (63.7%) in 131 patients had been re-evaluated at final followup in connection with plate and screw removal, on average 15.2 months postoperatively (range 8 to 62 months). Twelve symphyseal fractures, 23 fractures of the canine region, 28 fractures of the anterior part of the body, 26 fractures of the posterior part of the body and 83 angular fractures were assessed. Panoramic radiographs were taken pre- and postoperatively in all cases. Surgical technique
In patients in whom the fiacture involved the tooth-bearing area of the mandible, intravenous antimicrobial therapy consisting of penicillin G (1 million IU), usually combined with metronidazole (500 mg) was administered on admission and given every 6 h preand intraoperatively. Antimicrobial therapy was continued perorally (penicillin V 1 million IU and metronidazole 500 mg evey 6 h) until the 7th day after surgery. The operation was performed under general anaesthesia with nasotracheal intubation. The occlusion was re-established by bimanual manipulation, and secured using dental arch bars and IME Fixation was reinforced, if necessary, with cold-cure acrylic resin. The fracture sites were approached transorally (58 cases) or extraorally (212 cases). The transoral approach was chosen only in cases where, in the opinion of the surgeon, sufficient reduction and stabilization of the fracture could be achieved using this approach. For the extraoral approach, a submandibular incision as described by SPmSSL24was used, taking care not to damage the mandibular branch of the facial nerve by isolating it in the superior site of the wound. A nerve detector was always used. The periosteum was elevated from the mandible, exposing the fracture line. Final fracture reduction and osteosynthesis were performed using the instruments of the Synthes ® mandibular bone plate system (Synthes, Paoli, PA, USA) and AO/ASIF technique24. The repositioning was performed using reduction forceps, usually of the compression-reduction type, fixed with ~10 mm cortical screws (o 2.7 mm) at the lower border of the mandible. An interdental wire ligature was always applied when the fracture was located within the dental arch. In angular fractures and fractures in edentulous mandibles, a tension band plate was used only in cases in which fracture reduction at the upper border of the mandible could not be achieved by use of reduction forceps. Fractures were stabilized using rigid stainless steel plates bent to fit the contour of the buccal aspect of the mandible and fixed by bicortical screws. At least 2 screws were
79 150 t
[]
INTRAORAL
IN r ~'T~AnRAI 100"
