Comparison of Complication Rates Between Lateral Versus Inferior Fixation of Reconstruction Plate in Mandible Reconstruction Using Free Fibular Flap

Free fibular osteocutaneous flap is currently the first choice to reconstruct segmental mandibular defects (1). Among various techniques of fibular graft fixation, using reconstruction plate that provides rigid fixation for better bone union is a simple and reliable method for mandibular reconstruction. However, many complications associated to reconstruction site are also related to reconstruction plate (2). Therefore, the purpose of this study is to determine if the approach of fixing reconstruction plate over mandibular inferior margin, rather than the lateral aspect of mandible, can reduce complication rates.

Twenty patients undergone free fibular reconstruction of a segmental mandibular defect resulting from cancer excision between 2005 and 2009 were included in this retrospective review. Fixation of fibular flap was performed using Leibinger Mandible reconstruction system. Patients were divided into two groups based on the approach of fixation of mandibular reconstruction plate as Figure 1. Group 1 (lateral fixation approach) included 11 patients underwent mandibular reconstruction with the plates secured to the lateral aspect of the remaining native mandible. Group 2 (inferior fixation approach) included 9 patients with plates secured to the inferior margin of the remaining mandible. All patients received post-operative chemoradiation therapy due to advanced stage of oral cancer. Complications listed in Table 1 were recorded as cumulative incidence rate based on the length of follow-up. The cumulative incidence of complications was compared between groups by log-rank test.

Complication rates are summarized in Table 1. Lower but not statistically significant complication rate was identified in group 2 than that in group 1 with regard to screw loosening (3 versus 8 percent), plate extrusion (0 versus 19 percent), fistula or wound dehiscence (11 versus 21 percent), malocclusion (13 versus 18 percent), malunion (0 versus 9 percent). The mean follow-up for all 20 patients was 33.6 months. The mean time until each complication for group 2 versus group 1 was as follows: screw loosening, 24.3 versus 19.5 months; fistula or wound dehiscence, 28.7 versus 12.4 months; malocclusion, 20.1 versus 16.9 months.

Our study showed that inferior fixation of plate led to non-statistically significantly lower complication rate. If so, features of this approach that contribute to reduced complications are as follows. First, skin that overlies plate is subjected to necrosis as wound contracts over high-profile reconstruction plate. Fixation of plate over inferior mandibular margin largely reduces the area of skin overlying plate. Skin is better protected from necrosis by remaining mandible and revascularized graft. Second, inferior fixation provides easily accessible surgical field to achieve better mandible stump-fibular graft contact. Increased contact surface improves stability of fibular graft and minimize the number of screws used in bone graft that may disrupt its vascular supply. Moreover, when external cortical bone is involved by cancer, pre-plating technique can only be applied to inferior margin prior to resection. Overall, fixation of reconstruction plate over inferior margin could be a superior approach to reduce complications. Further investigation is warranted to support this conclusion.

1. Hidalgo DA, et al. Plast. Reconstr. Surg. 110: 438, 2002.

2. Klotch DW, et al. Otolaryngol. Head Neck Surg. 121: 388, 1999.

Table 1. Cumulative incidence rate of complications

Complication	Group 1 (Lateral fixation) (n = 11) (%)	Group 2 (Inferior fixation) (n = 9) (%)	p
Screw loosening	8/101 screws (8%)	2/66 screws (3%)	0.057
Plate extrusion	3 (19%)	0 (0%)	0.22
Plate fracture	0 (0%)	0 (0%)	1
Fistula or wound   dehiscence	2 (21%)	1 (11%)	0.73
Malocclusion	2 (18%)	1 (13%)	0.84
Malunion	1 (9%)	0 (0%)	0.78
Bone necrosis	0 (0%)	0 (0%)	1