Mandible Reconstruction Assisted by Preoperative Simulation and Transferring Templates: Cadaveric Study of Accuracy

Functional and esthetic outcomes of virtual surgical planning versus the conventional technique in mandibular reconstruction with a free fibula flap: A retrospective study of 24 cases

This study aimed to compare the functional and esthetic results in patients following mandibular reconstruction with a free fibula flap (FFF) by virtual surgical planning (VSP) versus the conventional technique. Patients who had undergone mandibular reconstruction with a FFF by VSP or the conventional technique were retrospectively assessed. The two groups were compared regarding functional and esthetic variables with appropriate scales preoperatively, intraoperatively, and postoperatively. Twenty-four patients were evaluated in two groups: conventional (n = 8) and VSP (n = 16). The mean amount of mandibular asymmetry was 2.62 mm (SD = 1.59) in the conventional group and 1.19 mm (SD = 1.32) in the VSP group. Of the patients who underwent conventional surgery, 12.5% had mandibular asymmetry of <2 mm and 87.5% had asymmetry of 2-5 mm. Of the VSP patients, 61.5% had mandibular asymmetry of <2 mm and 38.5% had mandibular asymmetry of 2-5 mm (p = 0.03). The mean difference in size of mandibular angle on the surgical and control sides was not significantly different between the two groups (p = 0.62). The difference in mean length of the mandibular body on the surgical side relative to the control side was not significant between the two groups (p = 0.75). Differences in functional variables between the two groups were not significant. Within the limitation of the study, it seems that the VSP technique resulted in better facial symmetry and superior esthetic outcomes compared with the conventional technique.

Application of a modified osteotomy and positioning integrative template system (MOPITS) based on a truncatable reconstruction model in the precise mandibular reconstruction with fibula free flap: a pilot clinical study

BACKGROUND

Mandibular defects can greatly affect patients' appearance and functionality. The preferred method to address this issue is reconstructive surgery using a fibular flap. The current personalized guide plate can improve the accuracy of osteotomy and reconstruction, but there are still some problems such as complex design process and time-consuming. Therefore, we modified the conventional template to serve the dual purpose of guiding the mandible and fibula osteotomy and facilitating the placement of the pre-bent titanium.

METHODS

The surgery was simulated preoperatively using Computer-Aided Design (CAD) technology. The template and truncatable reconstruction model were produced in the laboratory using 3D printing. After pre-bending the titanium plate according to the contour, the reconstruction model was truncated and the screw trajectory was transferred to form a modified osteotomy and positioning integrative template system (MOPITS). Next, the patient underwent a composite template-guided vascularized fibula flap reconstruction of the mandible. All cases were reviewed for the total operative time and accuracy of surgery.

RESULTS

The procedures involved 2-4 fibular segments in 15 patients, averaging 3 fibular segments per procedure. The osteotomy error is 1.01 ± 1.02 mm, while the reconstruction angular error is 1.85 ± 1.69°. The preoperative and postoperative data were compared, and both p > 0.05. During the same operation, implant placement was performed on four patients, with an average operative time of 487.25 ± 60.84 min. The remaining malignant tumor patients had an average operative time of 397.18 ± 73.09 min. The average postoperative hospital stay was 12.95 ± 3.29 days.

CONCLUSIONS

This study demonstrates the effectiveness of MOPITS in facilitating precise preoperative planning and intraoperative execution of fibula flap reconstruction. MOPITS represents a promising and reliable tool for reconstructive surgery, particularly for inexperienced surgeons navigating the challenges of mandible defect reconstruction.

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.

Evaluation of computer-aided design software methods for assessment of the three-dimensional geometry of the canine radius

OBJECTIVE

To describe methods to measure the 3-D orientation of the proximal, diaphyseal, and distal segments of the canine radius by use of computer-aided design software (CADS) and to compare the repeatability and reliability of measurements derived by those methods.

SAMPLE

31 canine radii with biapical deformities and 24 clinically normal (control) canine radii.

PROCEDURES

Select CT scans of radii were imported into a CADS program. Cartesian coordinate systems for the humerus and proximal, diaphyseal, and distal radial segments were developed. The orientation of each radial segment in the frontal, sagittal, and transverse planes was measured in triplicate by 3 methods. The repeatability and reliability of those measurements were calculated and compared among the 3 measurement methods.

RESULTS

The mean ± SD within-subject repeatability of radial angular measurements for all 3 methods was 1.40 ± 0.67° in the frontal plane, 3.17 ± 2.21° in the sagittal plane, and 3.01 ± 1.11° in the transverse plane for control radii and 2.56 ± 1.95° in the frontal plane, 3.59 ± 2.39° in the sagittal plane, and 3.47 ± 1.19° in the transverse plane for abnormal radii. Mean ± SD bias between radial measurement methods was 1.88 ± 2.07° in the frontal plane, 6.44 ± 6.80° in the sagittal plane, and 2.27 ± 2.81° in the transverse plane.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that use of CADS to assess the 3-D orientation of the proximal, diaphyseal, and distal segments of normal and abnormal canine radii yielded highly repeatable and reliable measurements.

Comparison of additive manufactured models of the mandible in accuracy and quality using six different 3D printing systems

The aim of this study was to analyze and compare the accuracy and quality of six 3D printing systems available on the market. Data acquisition was performed with 12 scans of human mandibles using an industrial 3D scanner and saved in STL format. These STL files were printed using six different printing systems. Previously defined distances were measured with a sliding caliper on the 72 printed mandibles. The printed models were then scanned once again. Measurements of volumes and surfaces for the STL files and the printed models were compared. Accuracy and quality were evaluated using industrial software. An analysis of the punctual aberration between the template and the printed model, based on a heat map, was also carried out. Secondary factors, such as costs, production times and expendable materials, were also examined. All printing systems performed well in terms of accuracy and quality for clinical usage. The Formiga P110 and the Form 2 showed the best results for volume, with average aberrations of 0.13 ± 0.23 cm³ and 0.12 ± 0.17 cm³, respectively. Similar results were achieved for the heat map aberration, with values of 0.008 ± 0.11 mm (Formiga P110) and 0.004 ± 0.16 mm (Form 2). Both printers showed no significant difference from the optimal neutral line (Formiga P110, p = 0.15; Form 2, p = 0.60). The cheapest models were produced by the Ultimaker 2+, with an average of 5€ per model, making such desktop printers affordable for rapid prototyping. Meanwhile, advanced printing systems with sterilizable and biocompatible printing materials, such as the Formiga P110 and the Form 2, fulfill the high expectations for maxillofacial surgery.

Accuracy of Fibula Reconstruction Using Patient-Specific Cad/Cam Plates: A Multicenter Study on 47 Patients

OBJECTIVES

This prospective study evaluated the accuracy of mandibular reconstruction using free fibular flaps (by comparing virtual plans to the three-dimensional postoperative results), and the extent of bone-to-bone contact after computer-assisted surgery.

METHODS

We included 65 patients who underwent partial-continuity mandibular resections from February 2013 to January 2017, and evaluated virtual planning, surgical techniques, and accuracy.

RESULTS

Forty-seven patients were analysed. A total of 112 fibular segments received 54 implants. We measured 227 distances between landmarks to assess the accuracy of reconstruction. Postoperative reconstruction accuracy ranged from 0.5 to 3 mm.

CONCLUSION

Virtual surgical planning very accurately translated simulation into reality, particularly in patients requiring large, complex mandibular reconstructions using multiple fibular segments.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2169-E2175, 2021.

Computer-assisted versus traditional technique in fibular free-flap mandibular reconstruction: A CT symmetry study

OBJECTIVES

In the past few years, virtual planning has been increasingly used for mandibular reconstruction. The objective of our study was to evaluate and compare symmetry and the accuracy of morphologic reconstruction in patients undergoing mandibular reconstruction by fibular free flap between traditional freehand technique and computer-aided surgical cutting guides.

MATERIAL AND METHODS

A single-center retrospective study included all cases of mandibular reconstruction using fibular free flap. In the three-dimensional (3D) group, virtual surgery planning with cut guides was used (Materialise ®), while the Control group underwent traditional freehand reconstruction. Morphometric comparisons were made to evaluate reconstruction accuracy between pre- and post-operative CT scans (mean deviations of 3 angles and 3 lengths). Mandible symmetry was calculated by comparing each angle and length in the affected and non-affected sides of the mandible.

RESULTS

Thirty-three patients treated between January 2015 and June 2018 were included: 25 patients in the 3D group and 8 in the control group. The average number of mandibular segments was 2.16±0.55 in the 3D group and 1.75±1.16 in the control group (p=0.005). Mean deviations between pre- and post-operative values of the coronal mandibular angle (angle formed by the line through the two condyles and the ramus), mandibular body height and mandibular ramus length on the affected side were significantly lower in the 3D group than in the control group. Sagittal mandibular angle symmetry was better in the 3D group than, in the control group (ratios of affected over non-affected sides: 1.07±0.04 vs 1.12±0.1; p=0.034).

CONCLUSION

Virtual surgical planning for fibula free-flap reconstruction helps to improve reconstruction accuracy and maintains a significantly greater symmetry than the traditional freehand technique, and should improve functional and esthetic outcome in mandibular reconstruction.

Three-Dimensionally Printed Patient-Specific Surgical Plates Increase Accuracy of Oncologic Head and Neck Reconstruction Versus Conventional Surgical Plates: A Comparative Study

Background

Surgeons are pursuing accurate head and neck reconstruction to enhance aesthetic and functional outcomes after oncologic resection. This study aimed to investigate whether accuracy of head and neck reconstruction is improved with the use of three-dimensionally (3D)-printed patient-specific surgical plates compared with conventional plates.

Methods

In this comparative study, patients were prospectively recruited into the study group (3DJP16) with 3D-printed patient-specific surgical plates. The patients in control group with conventional surgical plates were from a historic cohort in the same unit. The primary end point of the study was the accuracy of head and neck reconstruction. The secondary end points were accuracy of osteotomy, intraoperative blood loss, total operative time, and length of hospital stay.

Results

The study recruited of 33 patients, including 17 in the study group and 16 in the control group. The patients’ baseline characteristics were similar between the two groups. The absolute distance deviation of the maxilla or mandible was 1.5 ± 0.5 mm in the study group and 2.1 ± 0.7 mm in the control group [mean difference, − 0.7 mm; 95% confidence interval (CI) − 1.1 to − 0.3; p = 0.003], showing superior accuracy of reconstruction for the patients with 3D-printed patient-specific surgical plates. Improved accuracy of reconstruction also was detected in terms of bilateral mandibular angles and bone grafts. Concerning the secondary end points, the accuracy of the osteotomy was similar in the two groups. No difference was found regarding intraoperative blood loss, total operative time, or length of hospital stay.

Conclusions

This is the first study to prove that compared with conventional plates, 3D-printed patient-specific surgical plates improve the accuracy of oncologic head and neck reconstruction.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08732-y) contains supplementary material, which is available to authorized users.

The Shape of Things to Come: In-Hospital Three-Dimensional Printing for Mandibular Reconstruction Using Fibula Free Flap

OBJECTIVES/HYPOTHESIS

The aim of this study was to explore whether the production of in-hospital, low-cost surgical cutting guides would be possible and to assess different cutting guide shapes to facilitate the surgery and the application with instruments.

STUDY DESIGN

Cohort study.

METHODS

Using free computer-aided design software, surgical cutting guides for the mandible and fibula were designed and used to perform virtual segmental osteotomies and fibula transplants in seven patients.

RESULTS

Fourteen virtual osteotomies were performed using the free software and the proposed workflow. Thirteen guides were then printed to transfer the virtual planning information to the operating room.

CONCLUSIONS

Virtual planning and the three-dimensional (3D) printing of guides for mandibular reconstruction is reliable with the aid of an in-hospital 3D laboratory. We also demonstrated that different guides with different shapes could be produced with benefits during surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 2020.

New frontiers and emerging applications of 3D printing in ENT surgery: a systematic review of the literature

3D printing systems have revolutionised prototyping in the industrial field by lowering production time from days to hours and costs from thousands to just a few dollars. Today, 3D printers are no more confined to prototyping, but are increasingly employed in medical disciplines with fascinating results, even in many aspects of otorhinolaryngology. All publications on ENT surgery, sourced through updated electronic databases (PubMed, MEDLINE, EMBASE) and published up to March 2017, were examined according to PRISMA guidelines. Overall, 121 studies fulfilled specific inclusion criteria and were included in our systematic review. Studies were classified according to the specific field of application (otologic, rhinologic, head and neck) and area of interest (surgical and preclinical education, customised surgical planning, tissue engineering and implantable prosthesis). Technological aspects, clinical implications and limits of 3D printing processes are discussed focusing on current benefits and future perspectives.

Positioning accuracy of a patient-tailored rimmed wedge implant for corrective osteotomy of the distal radius

Conventional corrective osteotomy surgery is based on 2-D imaging for planning and evaluation of bone positioning. In this feasibility study we propose and evaluate the use of 3-D preoperative planning and design of a custom rimmed wedge to be inserted into the osteotomy gap. The shape of the wedge provides 3-D bone positioning as planned, while the rims keep the bone segments in place. The method is evaluated experimentally using 3-D printed radii specimens of five different malunion patients, as well as in a human cadaver specimen. Positioning was accurate and reproducible showing residual displacements along the x-, y- and z-axes of (mean ± SD): (-0.19 ± 0.75, 0.38 ± 1.09, and 0.47 ± 0.48) mm and residual rotations about these axes of (mean ± SD): (-1.22 ± 1.66, -0.40 ± 0.93, and -0.33 ± 1.50)° for artificial bone specimens. The cadaver experiment showed similar displacements along the x-, y- and z-axes (-0.17, 1.11, and -0.35) mm and residual rotations about these axes (-2.93, -1.53, and 2.31)°. Positioning by inserting a rimmed wedge in corrective osteotomy surgery is accurate with residual errors comparable to bilateral differences. The method seems promising for future utilization in corrective osteotomy surgery and may ultimately render the procedure minimally invasive.

Navigation Guidance During Free Flap Mandibular Reconstruction: A Cadaveric Trial

Importance

Segmental mandibulectomy for tumors that distort the buccal surface of the mandible present a reconstructive challenge.

Objective

To determine whether mandible alignment after navigation-guided mandible reconstruction is better than alignment after non-template-assisted freehand reconstruction and as good as template-assisted reconstruction in a cadaveric trial.

Design, Setting, and Participants

A cadaveric trial using 10 specimens was conducted at a tertiary academic center. Fiducials were created on the ramus to compare alignment with each intervention. Segmental mandibulectomy was performed on each cadaver. Each cadaver underwent navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction with plate contouring performed after mandibulectomy. The study was conducted from October 1, 2015, to January 1, 2016; data analysis was performed from February 1, 2016, to March 1, 2016.

Interventions

Segmental mandibulectomy, navigation-guided reconstruction, template-assisted reconstruction using a manually shaped plate, and non-template-assisted freehand reconstruction.

Main Outcomes and Measures

Ramus fiducial coordinates were recorded at baseline and after each intervention. Mandible dimensions were measured using cephalometric landmarks. Postintervention and baseline differences in ramus and mandible position were calculated.

Results

Ramus alignment was not significantly different between navigation-guided and template-assisted reconstruction, differing by 0.54 mm (98.3% CI, -0.38 to 1.47 mm). Non-template-assisted freehand reconstruction was associated with a 3.14-mm difference in alignment compared with template-assisted reconstruction (98.3% CI, 1.09 to 5.19 mm). Navigation-guided alignment resulted in a 3.69-mm improvement in alignment compared with non-template-assisted freehand reconstruction (98.3% CI, 1.79 to 5.58 mm). There was some improvement in the gonion-gonion and lingula mandibulae-lingula mandibulae (Lm-Lm) alignment for navigation-assisted compared with non-template-assisted freehand reconstruction by 1.97 mm (98.3% CI, -0.65 to 4.58 mm) and 1.39 mm (98.3% CI, -0.17 to 2.95 mm), respectively. There was marginal evidence of better Lm-Lm alignment for navigation-guided than template-assisted reconstruction (0.44 mm; 98.3% CI, -0.06 to 0.95 mm).

Conclusions and Relevance

Mandible alignment following navigation-guided reconstruction is similar to template-assisted reconstruction. Navigation-guided alignment is likely better than non-template-assisted freehand reconstruction, and navigation guidance offers a reliable technique for real-time adjustment when reconstructing complex surgical defects, such as tumors effacing the buccal cortex of the mandible.

Accuracy of virtually 3D planned resection templates in mandibular reconstruction

OBJECTIVE

Since reconstruction of composite defects in the head and neck region is a challenging and demanding problem for head and neck surgeons, surgical aids have been sought for decades. The purpose of this study was to evaluate the accuracy of prefabricated surgical resection templates used in mandibular segmental resections in comparison to the virtual surgical plan.

MATERIALS AND METHODS

A prospective study was performed in 11 consecutive patients, with a primary T4 oral squamous cell carcinoma or osteoradionecrosis of the mandible. Preoperatively, a CBCT scan was acquired to delineate the size and extension of tumor invasion; a virtual patient-specific resection template was designed based on this information. Intraoperatively, the resection template was positioned on the mandible and secured using four fixation screws. Postoperatively, a CBCT scan was acquired. This scan was superimposed on the preoperative scan. Positioning of the resection template and inclination of the resection planes were evaluated on the virtual head model. In order to test the interobserver reliability of these new measurement methods, two different observers executed all measurements.

RESULTS

The mean shift of the proximal resection templates was 3.76 mm (standard deviation [SD] 3.10 mm). For the distal resection templates, the mean shift was 3.06 mm (SD 1.57 mm) with no significant interobserver difference (ICC = 0.99). An absolute mean deviation of 8.5° (SD 5.3°) was found for the proximal resection angle and 10.4° (SD 5.0°) for the distal resection angle. Again, no significant interobserver differences were found (ICC = 0.98).

CONCLUSION

The resection templates used in this study proved reasonably accurate. Although the concept of virtual surgical planning aids significantly in mandibular reconstruction with microvascular free flaps, further improvement of resection accuracy is necessary for further improvement of reconstruction accuracy.

Low-cost Design and Manufacturing of Surgical Guides for Mandibular Reconstruction Using a Fibula

Background:

Surgical cutting guides are used in mandibular reconstruction involving osteotomy of the mandible and fibula. Cutting guides produced using computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies have been reported recently. These guides aim to increase the benefits to patients by improving the accuracy, shortening the operating time, and correcting occlusion. However, the availability of these advanced technologies is limited in some regions of the world. To test whether we could produce low-cost surgical cutting guides, we made surgical guides and investigated their accuracy.

Methods:

Using free CAD software, we designed surgical cutting guides for the mandible and fibula and used these to perform virtual mandibular segmental osteotomies and fibula transplants in 12 model surgeries. The cutting guides were printed on a 3-dimensional (3D) printer. The model surgeries were performed using 3D mandibular models and cutting guides to check their accuracy. Deviations between the virtually simulated plan and the actual model surgery were investigated.

Results:

CAD and CAM technologies were used to design and 3D print the cutting guides and models. The guided surgeries were performed. The deviations were about 1.3 mm for mandibular osteotomy, less than 1 mm for fibular osteotomy, and within 2.4 mm for reconstructions of the mandible.

Conclusions:

Without using expensive software or products, we were able to design surgical cutting guides for the mandible and fibula and used these to perform virtual simulation of mandibular segmental osteotomy and fibular reconstruction. Model surgeries using 3D-printed surgical guides showed that the accuracy of reconstruction was within a 3-mm deviation. In circumstances where commercial CAD/CAM guides are not available, it may be possible to use CAD/CAM surgical guides in the clinic if doctors are willing to volunteer their time for the design and printing.

Precision of fibula positioning guide in mandibular reconstruction with a fibula graft

Background

This study examined the usefulness of the fibula positioning guide for boosting the accuracy of mandible reconstructions.

Methods

Thirty mandibular rapid prototype (RP) models were allocated to experimental (N = 15) and control (N = 15) groups. For reference, we prepared a reconstructed mandibular RP model with a three-dimensional printer, based on surgical simulation. In the experimental group, a fibula positioning guide template and fibula cutting guide, based on simulation, were used to reconstruct the mandible with a fibula graft. In the control group, only the fibula cutting guide, with reference to the reconstructed RP mandible model, was used to reconstruct the mandible with a fibula graft. The two mandibular reconstructions were compared to the surgical simulation by registering images with the non-surgical right side of the mandible. On the reconstructed side, 3D measurements were compared between the surgical simulation and actual surgery, and the sum of differences was taken as the total error.

Results

The combined use of the fibula cutting and positioning guides produced a smaller total error (mean ± SD: 10.0 ± 7.9 mm) than the fibula cutting guide alone (12.8 ± 8.8 mm; p = 0.015). The greatest point error was the vertical error at the mesial point of the anterior fibula segment. The anteroposterior and lateral errors were not significantly different between groups. These results showed that these two methods were not significantly different, except in the total and vertical errors.

Conclusions

Considering the CAD/CAM processes required for creating positioning devices, the benefit provided with a positioning guide justified its use over the fibula cutting guide alone.

Preliminary clinic study on computer assisted mandibular reconstruction: the positive role of surgical navigation technique

Background

The objectives of the present study were to investigate the reliability and outcomes of computer-assisted techniques in mandibular reconstruction with a fibula flap and verify whether the surgical navigation system was feasible in mandible reconstructive surgery.

Methods

Eight cases were enrolled in the computer assisted surgery (CAS) group and 14 cases in the traditional group. The shaping and fixation of the fibula grafts were guided by computer assisted techniques, which could be monitored with the BrainLAB surgical navigation system. The variation of mandible configuration was evaluated by CT measurement in the Mimics software, including the variation of length, width, height and gonial angle of the mandible. The 3D facial soft tissue alteration was also analyzed in 3D chromatogram by Geomagic software.

Results

All 22 fibula flaps survived. The mandibular configurations and facial contours had a better clinic result in the CAS group. The length, width, height and gonial angle of the reconstructive mandible were more similar to the original one. The Wilcoxon rank sum test analysis suggested significant differences in the measurements. The chromatographic analysis also visually showed superiority over the traditional group.

Conclusions

The computer assisted surgical navigation method used in mandibular reconstruction is feasible and precise for clinical application. The contour of the reconstructed mandible and facial symmetry are improved with computer techniques.

Patient-specific reconstruction plates are the missing link in computer-assisted mandibular reconstruction: A showcase for technical description

INTRODUCTION

Preoperative planning of mandibular reconstruction has moved from mechanical simulation by dental model casts or stereolithographic models into an almost completely virtual environment. CAD/CAM applications allow a high level of accuracy by providing a custom template-assisted contouring approach for bone flaps. However, the clinical accuracy of CAD reconstruction is limited by the use of prebent reconstruction plates, an analogue step in an otherwise digital workstream.

TECHNICAL REPORT

In this paper the integration of computerized, numerically-controlled (CNC) milled, patient-specific mandibular plates (PSMP) within the virtual workflow of computer-assisted mandibular free fibula flap reconstruction is illustrated in a clinical case. Intraoperatively, the bone segments as well as the plate arms showed a very good fit. Postoperative CT imaging demonstrated close approximation of the PSMP and fibular segments, and good alignment of native mandible and fibular segments and intersegmentally. Over a follow-up period of 12 months, there was an uneventful course of healing with good bony consolidation.

CONCLUSION

The virtual design and automated fabrication of patient-specific mandibular reconstruction plates provide the missing link in the virtual workflow of computer-assisted mandibular free fibula flap reconstruction.

Considerations and Protocols in Virtual Surgical Planning of Reconstructive Surgery for More Accurate and Esthetic Neomandible with Deep Circumflex Iliac Artery Free Flap

Purpose:

The reconstruction of mandibular defects poses many difficulties due to the unique, complex shape of the mandible and the temporomandibular joints. With development of microvascular anastomosis, free tissue transplantation techniques, such as deep circumflex iliac artery (DCIA) flap and fibular free flap (FFF), were developed. The DCIA offers good quality and quantity of bone tissue for mandibular segmental defect and implant for dental rehabilitation. Virtual surgical planning (VSP) and stereolithography-guided osteotomy are currently successfully applied in three-dimensional mandibular reconstruction, but most use FFF. There are only a few articles on reconstruction with the DCIA that assess the postoperative results.

Methods:

Three patients admitted during a five month period (April of 2013 to August of 2013) underwent resection of mandible and DCIA musculo-osseous reconstruction using a VSP and stereolithographic modeling and assessment of outcomes included technical accuracy, esthetic contour, and functional outcomes.

Results:

This technique yielded iliac bone segment with excellent apposition and duplication of the preoperative plan. Flap survival was 100 percent and all patients maintained preoperative occlusion and contour.

Conclusion:

Based on our experience, we offer considerations and logically consistent protocols by classification of mandibular defects, and demonstrate the benefits in VSP and stereolithographic modeling of mandibular reconstructive surgery with DCIA flap.

[Surgery guided by customized devices: reconstruction with a free fibula flap]

The reconstruction of jaws with a free fibula flap can be anticipated virtually. The simulation can be transferred to the operating theater using customized devices obtained from computer-assisted design and manufacturing in a complete digital workflow. Several alternatives are available, from cutting guides to customized titanium osteosynthesis plates, to obtain the best accuracy and reproducibility of reconstruction. Moreover, these new processes allow integrating prosthetic planning concomitantly with reconstruction. We present the virtual three-dimensional planning method for jaw reconstruction with a free fibula flap and the various alternatives of surgery guided by customized devices provided by this planning.

[Stereomodel-assisted fibula free flap harvest and mandibular reconstruction: A technical note. Literature review of CAS and CAM applied to mandibular reconstruction]

PURPOSE

Mandibular reconstruction with fibula free flap harvest is currently the reference technique. Various preoperative processes have been developed to optimize this reconstruction. We report our experience with a simple, inexpensive, preoperative technique requiring a 3D printer, a device for maintaining mandibular reduction, a paper-cutting guide.

TECHNICAL NOTE

Stereomodels of the mandible were obtained from computed tomography scan data and printed 3D in ABS. It allowed planning mandibular osteotomies, determine the angle between two bone fragments, and preoperatively modeling the osteosynthesis plate. A paper-cutting guide, and a simple device for maintaining mandibular reduction were also built. Two patients were operated on with this technique, with follow-up at 6 and 8 months. Reconstructions were successful with good clinical outcome in terms of mandibular contour and reconstructed segments positions.

DISCUSSION

Preoperative planning of reconstruction may be used for mandibular osteotomies, fibular osteotomies, maintaining mandibular reduction, osteosynthesis, or placing implants for dental rehabilitation. The most complex procedures can virtually plan all these steps, but they are expensive and long to implement. Nevertheless, such procedures are quite expansive and require time not always compatible with carcinoma. Using a mandibular stereomodel is fast, easy, and cheap.

Patient-tailored plate for bone fixation and accurate 3D positioning in corrective osteotomy

A bone fracture may lead to malunion of bone segments, which gives discomfort to the patient and may lead to chronic pain, reduced function and finally to early osteoarthritis. Corrective osteotomy is a treatment option to realign the bone segments. In this procedure, the surgeon tries to improve alignment by cutting the bone at, or near, the fracture location and fixates the bone segments in an improved position, using a plate and screws. Three-dimensional positioning is very complex and difficult to plan, perform and evaluate using standard 2D fluoroscopy imaging. This study introduces a new technique that uses preoperative 3D imaging to plan positioning and design a patient-tailored fixation plate that only fits in one way and realigns the bone segments as planned. The method is evaluated using artificial bones and renders realignment highly accurate and very reproducible (d(err) < 1.2 ± 0.8 mm and φ(err) < 1.8° ± 2.1°). Application of a patient-tailored plate is expected to be of great value for future corrective osteotomy surgeries.