Osseous Union after Jaw Reconstruction with Fibula-Free Flap: Conventional vs. CAD/CAM Patient-Specific Implants

Abstract

This is a monocentric, retrospective study of patients who underwent successful immediate or delayed maxilla or mandible reconstructions with FFF from January 2005 to December 2021. Panoramic radiograph, computed tomography scans, and cone-beam CTs were analyzed concerning the osseous union of the intersegmental junctions between maxillary or mandibular native jaw and fibular bone. The primary parameter was to estimate the status of osseous union according to osteosynthesis type. A total number of 133 patients (PSI: n = 64, non-PSI: n = 69) were included in the present study. The mean age was 56.7 ± 14.0 (Range: 14.7–82.7); the primary diagnosis was in 105 patients a malignant (78.9%) and in 20 patients a benign (15.0%) tumor. Mandible reconstruction was performed on 103 patients (77.4%), and on 30 patients (22.6%), maxilla reconstruction was performed. The radiographic images provided a rate of incomplete osseous union (IOU) of about 90% in both groups in the first 6 months. Imaging between 6 and 12 months reveals an IOU rate in the non-PSI group of 46.3% vs. 52.5% in the PSI group, between 12 and 24 months, an IOU rate of 19.6% vs. 26.1%, between 24 and 36 months 8.9% vs. 21.7%, and after 36 months the IOU rate decreases to 4.2% vs. 18.2%. Multivariate logistic regression shows that only osteosynthesis type (OR = 3.518 [95%-CI = 1.223–10.124], p = 0.02) and adjuvant radiotherapy (OR = 4.804 [95%-CI = 1.602–14.409], p = 0.005) are independent risk factors for incomplete osseous union. Cox regression revealed that the variables plate-system (Hazard ratio, HR = 5.014; 95 %-CI: 1.826–3.769; p = 0.002) and adjuvant radiotherapy (HR = 5.710; 95 %-CI: 2.066–15.787; p < 0.001) are predictors for incomplete osseous union. In our study, the rate of incomplete bony fusion was significantly higher in the PSI group. Jaw-to-fibula apposition zones were significantly more affected than intersegmental zones. In multivariate analysis, a combination of osteosynthesis with PSI and adjuvant radiotherapy could be identified as a risk constellation for incomplete ossification.

Evaluating the benefit of virtual surgical planning on bony union rates in head and neck reconstructive surgery

“…In a comparison of FHS and VSP with customized patient specific implants for mandibular reconstruction with fibular free flap, Knitschke et al observed slightly earlier complete bony union in patients in the patient-specific implants group than in patients in the FHS group. 20 However, in contrary to our results, the rate of incomplete bony union was significantly higher in the patient-specific implant group. 20 There are several proposed explanations for the difference in union rates.…”

“…6,7,[14][15][16] While several studies have reported on the bony union status of maxillary and mandibular reconstruction, 4,12,[17][18][19] fewer compare this outcome between VSP and FHS. 11,16,20 To the best of our knowledge, our study is the first comparing the rate of union in FHS and VSP in patients undergoing either mandible or maxilla reconstruction with either fibular or scapular free-flap. By including both sites of reconstruction and origins of free-flap, we were able to demonstrate that these variables had no significant effect on the rate of union.…”

“…As well, there is uncertainty about the appropriate timing of imaging following surgery to assess bony union and variability in the imaging modality employed to make the assessment. Similar studies comparing the rate of bony union in FHS and VSP used different radiological modalities across their patients for the assessment of bony union including: radiograph, panorex, CT and PET CT. 16,20 In our study, CT was used for the radiological assessment of bony union in all patients. We used a grading system that was adapted from those previously published with clear radiological definitions of what constitutes non-union, partial union and complete union leading to high inter-rater agreement.…”

In‐house virtual surgical planning and guided mandibular reconstruction is less precise, but more economical and time‐efficient than commercial procedures

“…Intersegmental volumes and gap widths are critical in this regard, and we were able to show that they were significantly smaller in the commercial planning group compared to the in‐house planning group. Knitschke and colleagues confirmed this finding for intersegmental volumes and observed earlier ossification of the segments, which is critical for adequate graft healing 26 . Tran et al also measured smaller gaps in a commercial planning solution that integrated PSIs 27 .…”

“…Knitschke and colleagues confirmed this finding for intersegmental volumes and observed earlier ossification of the segments, which is critical for adequate graft healing. 26 Tran et al also measured smaller gaps in a commercial planning solution that integrated PSIs. 27 Compared to the in-house solution, the commercial planning solution offers the advantage of virtually modeling and fabricating a PSI in a laser sintering or milling process that precisely fits the patient's reconstructed mandible.…”