Computer simulation surgery for mandibular reconstruction using a fibular osteotomy guide

Dual Application of Patient-Specific Occlusion-Based Positioning Guide and Fibular Cutting Guide for Accurate Reconstruction of Segmental Mandibular Defect

In this study, the authors introduced a dual application of patient-specific occlusion-based positioning guide and fibular cutting guide to obtain ideal occlusal relationship and mandibular contour in patients undergoing mandibular reconstruction. A retrospective review was performed in 21 patients who underwent mandibular reconstruction with a fibular osteocutaneous free flap. Using computed tomography and intraoral scanning data, fibular cutting guide and occlusion-based positioning guide were simulated in a modeling software and 3-dimensionally printed. Both guides were applied in 9 patients, defined as dual guide group, while the fibular cutting guide was solely used in the remaining patients, defined as single guide group. Functional outcomes including occlusion status, trismus, presence of osseointegrated implant were assessed at 1-year postoperative period. To evaluate the accuracy of the reconstruction, the discrepancy between the planned simulation and actual surgical result was quantified by measuring mandibular deviation angle and volume conformity. Regarding the functional outcomes, all patients in dual guide group showed satisfactory occlusion and intact oral capacity at postoperative 1-year assessment, while 3 patients in single guide group had prolonged malocclusion. The dual guide group showed significantly decreased deviation angle in coronal (right side, 2.93°±1.98° vs. 7.02°±2.81°, P =0.003) and axial plane (right side, 3.20°±2.04° vs. 7.63°±3.40°, P =0.006). The mean volume conformity between the simulation and actual fibular object was significantly higher in the dual guide group (75.27%±6.12% vs. 59.06%±8.57%, P =0.001). In conclusion, the use of occlusion-based positioning guide combined with the fibular cutting guide can enhance the accuracy of mandible reconstruction and functional outcomes.

Application of optimized digital surgical guides in mandibular resection and reconstruction with vascularized fibula flaps: Two case reports

RATIONALE

Currently, digital surgical techniques have been widely used in the precise treatment of mandibular resection and reconstruction with fibula flaps. Utilizing these innovative techniques in surgical planning and hardware fabrication before surgery has shown to provide great help. However, it is difficult for even experienced surgeons to place the preformed reconstruction plate in the same position as its preoperative design, causing surgical results to differ from preoperative planning. This study aims to solve these acknowledged challenges by creating newly designed equipment.

PATIENT CONCERNS

Two patients suffering from long-term expansion of the mandible were admitted to our department. Case I was a 39-year-old female patient who was concerned about the disease in the middle of the mandible, Case II was a 45-year-old female patient who was concerned about the disease at the left mandibular angle and ramus region.

DIAGNOSES

Two patients were diagnosed with the mandibular ameloblastoma based on computed tomography (CT) scan and pathological results.

INTERVENTIONS

Personalized 3-dimensional (3D) surgical guides were applied to 2 patients with mandibular ameloblastoma who underwent mandibular resection and reconstruction with vascularized fibula flaps using a specially optimized and designed reconstruction guide plate.

OUTCOMES

We achieved precise mandibular repair with such a guide in full accordance with the preoperative plan and ensured the restoration of patient facial symmetry.

LESSONS

Optimized reconstruction guide template could accurately locate the preformed reconstruction plate. This component had the ability to ensure that the location of the actual reconstruction plates were highly consistent with preoperative designed models.

Advantages of surgical simulation in the surgical reconstruction of oncological patients

Background

Stereolithography, which consists of computer-aided designed/computer-aided manufactured (CAD-CAM) and computer simulations, is a manufacturing technologies used for the production of definitive models and prototypes printed in three dimensions, and is widely used in Oral and Maxillofacial Surgery. Surgical procedures using models made by these technologies offer several advantages.

Material and Methods

This article describes three clinical cases of our experiences with patients diagnosed with squamous cell carcinoma and mandibular osteosarcoma, who underwent surgical removal of the lesions and subsequent mandibular reconstruction with a free fibula graft using surgical guides.

Results

In all three clinical cases, surgical guides were used for the mandibular osteotomy, fibula osteotomy, and graft placement in the recipient area.

Conclusion

Surgical guidelines are useful for improving the accuracy of surgical interventions and are appropriate for many types of resection and mandibular reconstruction.

Key words:Fibula flap, virtual surgical planning, mandibular reconstruction, precise medicine.

[Estimated error of bone digital solid 3D-model construction algorithm]

The aim of the study was an experimental estimation of precision of maxilla bone digital solid 3D-model construction algorithm. The experiment was carried out on 12 mutton mandibles used 3D-model construction based on CT data. Estimated error was calculated for each of the stages of proposed processing algorithm including 3 software: ScanIP (triangle mesh calculation, primary solid 3D-model), ArtecStudio 9 (secondary procession for artefacts elimination), ZBrush 4R6 (triangle mesh simplification, final 3D-model). The proposed algorithm provides satisfactory precision for solid 3D-model with individual maxillary bone features.

Clinical experience with 80 microvascular couplers in 64 free osteomyocutaneous flap transfers for mandibular reconstruction

Microvascular couplers have been introduced as an alternative method for anastomosis in mandibular reconstruction. This study included 64 patients who had undergone free flap reconstruction for mandibular defects and had been scheduled for follow-up at 1, 3, 6, and 12 months. After completion of the tumour resection and harvesting of the osteomyocutaneous flap, appropriate preparation of both ends of the vessels was performed for microsurgery. Single-vein anastomoses were performed in 35 patients and double-vein anastomoses in 29 patients. Except for 75 couplers used for venous anastomosis only, both arterial and venous anastomoses were performed using the coupler in seven flaps. No flap failures occurred in these cases, resulting in an overall flap success rate of 100%. As expected, anastomoses were completed successfully using the coupler in 78 out of 80 attempted cases (97.5%). Additional large and randomized studies are needed to compare the outcomes of coupler anastomoses to those of traditional sutured anastomoses, and to define to what extent this would present cost-savings per procedure.