Virtual planning and guided surgery in fibular free-flap mandibular reconstruction: A 29-case series

A 3D Analysis of Plating Strategies in Mandibular Reconstruction: A Randomized Control Pilot Study

OBJECTIVE(S)

The purpose of this study was to compare computer-assisted mandibular plating to conventional plating using quantitative metrics.

METHODS

Patients scheduled to undergo mandibular reconstruction were randomized to three-dimensional modelling for preoperative plate bending or intraoperative freehand bending. Preoperative and postoperative head and neck computed tomography scans were obtained to generate computer models of the reconstruction. The overall plate surface contact area, mean plate-to-bone distance, degree of conformance, and position of the condylar head within the glenoid fossa between pre- and post-operative scans were calculated.

RESULTS

Twenty patients were included with a mean age of 57.8 years (standard deviation [SD] = 13.6). The mean follow-up time was 9.8 months (range = 1.6-22.3). Reconstruction was performed with fibular (25%) or scapular free flaps (75%). The percentage of surface contact between the reconstructive plate and mandible was improved with three-dimensional models compared to freehand bending (93.9 ± 7.7% vs. 78.0 ± 19.9%, p = 0.04). There was improved overall plate-to-bone distance (3D model: 0.7 ± 0.31 mm vs. conventional: 1.3 ± 0.8 mm, p = 0.06). Total intraoperative time was non-significantly decreased with the use of a model (3D model: 726.5 ± 89.1 min vs. conventional: 757.3 ± 84.1 min, p = 0.44). There were no differences in condylar head position or postoperative complications.

CONCLUSION

Computer-assisted mandibular plating can be used to improve the accuracy of plate contouring.

LEVEL OF EVIDENCE

2 Laryngoscope, 134:2182-2186, 2024.

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.

Impact of virtual surgical planning and three-dimensional modeling on time to surgery in mandibular reconstruction by free fibula flap

PURPOSE

Mandible reconstruction using a free fibula flap (FFF) is preferably performed with virtual surgical planning (VSP) to potentially improve functional and aesthetic outcomes. However, VSP is time-consuming. This study aims to assess the impact of VSP on time to surgery (TS).

MATERIALS AND METHODS

All patients who underwent FFF for oral cavity cancer between 2007 and 2020 were included. Time to surgery (from the date of the first consultation to the surgery date) was compared between patients without VSP and with VSP. In our department, VSP and 3D modeling were performed by an external engineering laboratory.

RESULTS

One hundred sixty-five patients were included retrospectively. VSP was utilized for 90 patients (55%). The mean time to surgery was 31 ± 16 days for patients undergoing conventional surgery without VSP and 44 ± 19 days for patients with VSP (p < 0.001). No clinical or tumoral characteristic were associated with a TS extended, except for the utilization of VSP (p < 0.001). By constituting groups of 25 consecutive patients, there is no difference in TS between the groups.

CONCLUSION

The use of VSP significantly increased the time to surgery in our study, unrelated to clinical differences or year of surgery. This delay may have an impact on oncologic outcomes, so it should be considered in the care organization for each patient. Implementing new procedures to reduce this difference is warranted.

Digital template-guided genioplasty for patients with jaw deformity resulting from temporomandibular joint ankylosis: A comparison between single- and double-layer genioplasty

The aim of this study was to compare single- and double-layer digital template-assisted genioplasty for the correction of jaw deformity resulting from temporomandibular joint ankylosis (TMJA). Thirteen patients with jaw deformity resulting from TMJA who underwent lateral arthroplasty, costochondral graft, or total joint replacement combined with single- or double-layer digital template-assisted genioplasty were included. Computed tomography data were obtained for the preoperative design. Digital templates were designed and manufactured using three-dimensional printing to assist with the chin osteotomy and repositioning in single- or double-layer genioplasty. Of the 13 patients included, seven underwent single-layer genioplasty and six underwent double-layer genioplasty. The digital templates precisely reflected the osteotomy planes and repositioning of the chin segments intraoperatively. The radiographic evaluation showed that the patients who underwent double-layer genioplasty exhibited more chin advancement (11.95 ± 0.92 mm vs 7.50 ± 0.89 mm; P < 0.001) with a slightly larger mean surface error (1.19 ± 0.14 mm vs 0.75 ± 0.15 mm; P < 0.001) than those who underwent single-layer genioplasty. This indicates that double-layer genioplasty better promoted chin advancement and improved the facial shape, but was accompanied by more surgical error compared with the preoperative design. Furthermore, hardly any nerve damage was observed. Digital templates are useful for assisting in surgical procedures.

The Cost Utility of Virtual Surgical Planning and Computer-Assisted Design/Computer-Assisted Manufacturing in Mandible Reconstruction Using the Free Fibula Osteocutaneous Flap

BACKGROUND

 The use of virtual surgical planning and computer-assisted design and computer-assisted manufacturing (CAD/CAM) has become widespread for mandible reconstruction with the free fibula flap. However, the cost utility of this technology remains unknown.

METHODS

 The authors used a decision tree model to evaluate the cost utility, from the perspective of a hospital or insurer, of mandible reconstruction using CAD/CAM relative to the conventional (non-CAD/CAM) technique for the free fibula flap. Health state probabilities were obtained from a published meta-analysis. Costs were estimated using 2018 Centers for Medicare and Medicaid Services data. Overall expected cost and quality-adjusted life-years (QALYs) were assessed using a Monte Carlo simulation and sensitivity analyses. Cost effectiveness was defined as an incremental cost utility ratio (ICUR) less than the empirically accepted willingness-to-pay value of $50,000 per QALY.

RESULTS

 Although CAD/CAM reconstruction had a higher expected cost compared with the conventional technique ($36,487 vs. $26,086), the expected QALYs were higher (17.25 vs. 16.93), resulting in an ICUR = $32,503/QALY; therefore, the use of CAD/CAM in free fibula flap mandible reconstruction was cost-effective relative to conventional technique. Monte Carlo sensitivity analysis confirmed CAD/CAM's superior cost utility, demonstrating that it was the preferred and more cost-effective option in the majority of simulations. Sensitivity analyses also illustrated that CAD/CAM remains cost effective at an amount less than $42,903 or flap loss rate less than 4.5%.

CONCLUSION

 This cost utility analysis suggests that mandible reconstruction with the free fibula osteocutaneous flap using CAD/CAM is more cost effective than the conventional technique.

Investigating the accuracy of mandibulectomy and reconstructive surgery using 3D customized implants and surgical guides in a rabbit model

BACKGROUND

This study aimed to analyze the accuracy of the output of three-dimensional (3D) customized surgical guides and titanium implants in a rabbit model, and of mandibulectomy, reconstructive surgery, and surgical outcome; additionally, the correlation between surgical accuracy and surgical outcomes, including the differences in surgical outcome according to surgical accuracy, was analyzed.

RESULTS

The output of implants was accurately implemented within the error range (- 0.03-0.03 mm), and the surgical accuracy varied depending on the measured area (range - 0.4-1.1 mm). Regarding surgical outcomes, angle between the mandibular lower borders showed the most sensitive results and distance between the lingual cusps of the first molars represented the most accurate outcomes. A significant correlation was noted between surgical accuracy in the anteroposterior length of the upper borders pre- and postoperatively and the angle between the mandibular lower borders (regression coefficient = 0.491, p = 0.028). In the group wherein surgery was performed more accurately, the angle between the mandibular lower borders was reproduced more accurately (p = 0.021). A selective laser melting machine accurately printed the implants as designed. Considering the positive correlation among surgical accuracy in the mandibular upper borders, angle between the mandibular lower borders, and more accurately reproduced angle between the mandibular lower borders, the angle between the mandibular lower borders is considered a good indicator for evaluating the outcomes of reconstructive surgery.

CONCLUSION

To reduce errors in surgical outcomes, it is necessary to devise a positioner for the surgical guide and design a 3D surgical guide to constantly maintain the direction of bone resection. A fixed area considering the concept of three-point fixation should be selected for stable positioning of the implant; in some cases, bilateral cortical bone fixation should be considered. The angle between the mandibular lower borders is a sensitive indicator for evaluating the outcomes of reconstructive surgery.

Mandible segmentation from CT data for virtual surgical planning using an augmented two-stepped convolutional neural network

PURPOSE

For computer-aided planning of facial bony surgery, the creation of high-resolution 3D-models of the bones by segmenting volume imaging data is a labor-intensive step, especially as metal dental inlays or implants cause severe artifacts that reduce the quality of the computer-tomographic imaging data. This study provides a method to segment accurate, artifact-free 3D surface models of mandibles from CT data using convolutional neural networks.

METHODS

The presented approach cascades two independently trained 3D-U-Nets to perform accurate segmentations of the mandible bone from full resolution CT images. The networks are trained in different settings using three different loss functions and a data augmentation pipeline. Training and evaluation datasets consist of manually segmented CT images from 307 dentate and edentulous individuals, partly with heavy imaging artifacts. The accuracy of the models is measured using overlap-based, surface-based and anatomical-curvature-based metrics.

RESULTS

Our approach produces high-resolution segmentations of the mandibles, coping with severe imaging artifacts in the CT imaging data. The use of the two-stepped approach yields highly significant improvements to the prediction accuracies. The best models achieve a Dice coefficient of 94.824% and an average surface distance of 0.31 mm on our test dataset.

CONCLUSION

The use of two cascaded U-Net allows high-resolution predictions for small regions of interest in the imaging data. The proposed method is fast and allows a user-independent image segmentation, producing objective and repeatable results that can be used in automated surgical planning procedures.

Reconstruction of the mandible from partial inputs for virtual surgery planning

Statistical Shape Models (SSMs) and Sparse Prediction Models (SPMs) based on regressions between cephalometric measurements were compared against standard practice in virtual surgery planning for reconstruction of mandibular defects. Emphasis was placed on the ability of the models to reproduce clinically relevant metrics. CT scans of 50 men and 50 women were collected and split into training and testing datasets according to an 80:20 ratio. The scans were segmented, and anatomical landmarks were identified. SPMs were constructed based on direct regressions between measurements derived from the anatomical landmarks. SSMs were developed by establishing correspondence between the segmented meshes, performing alignment, and principal component analysis. Anterior and bilateral defects were simulated by removing sections of the mandibles in the testing set. Measurement errors after reconstruction ranged from 1.07˚ to 2.2˚ and 0.66 mm to 2.02 mm for mirroring, from 0.45˚ to 3.67˚ and 0.66 mm to 2.54 mm for the SSMs, and from 1.74˚ to 5.01˚ and 0.64 mm to 2.89 mm for the SPMs. Surface-to-surface errors ranged from 1.01 mm to 1.29 mm and 1.06 mm to 1.33 mm for mirroring and SSMs, respectively. Based on the results, SSMs are recommended for VSP in the absence of normal patient anatomy.

Aesthetic reconstruction of onco-surgical maxillary defects using free scapular flap with and without CAD/CAM customized osteotomy guide

BACKGROUND

Reconstruction of the maxillary defects following tumor ablation remains to be a challenge for surgeons. Virtual surgical planning (VSP), intraoperative cutting guides and stereolithographic models provides the head and neck reconstructive surgeon with powerful tools for complex reconstruction planning. Despite its use in fibular osteocutaneous reconstruction, application to the scapular free flap has not been as widely reported. The aim of this study was to compare aesthetic results and operation time of free scapular flap, with and without computer-aided design and computer-aided manufacturing (CAD/CAM) customized osteotomy guide, for reconstruction of maxillary defects.

METHODS

In this prospective randomized controlled clinical trial study, we randomly assigned 22 patients with maxillary defects who were scheduled to undergo maxillary reconstruction with either free scapular flap with CAD/CAM customized osteotomy guide; study group (n = 11) or free scapular flap without CAD/CAM customized osteotomy guide; control group (n = 11). All patients were followed up for 3 months. The aesthetic outcome, operation and ischemic times were evaluated and compared.

RESULTS

Aesthetic outcomes were evaluated objectively by means of differential surface area (sagittal and axial) measurement, which showed improved aesthetic outcome (contour symmetry) in the study group with a mean of (241.39 ± 113.74 mm²), compared to patients in control group with a mean of (358.70 ± 143.99 mm²). There were significant differences between the two groups (P < 0.05). Aesthetic outcomes were also evaluated subjectively by means of visual analogue scale (VAS) and patient's satisfaction score (PSS). The postoperative aesthetic appearance was better in the study group with more patients satisfied than that in control group and there were statistically significant differences (P = 0.039). The mean total operative time was 678.81 min and 777.18 min in the study group and control group respectively (P < 0.05) and the mean ischemia time was 133.18 min and 195.72 min for study group and control group respectively (P < 0.05). The ischemia time and total operative time were shorter in the study group compared to those in the control group and there were no flap losses in both groups.

CONCLUSION

The use of CAD/CAM prefabricated cutting guides facilitates scapular flap molding and placement, minimizes ischemic time and operating time as well as improves aesthetic outcomes. Trial registration This trial was registered at ClinicalTrials.gov.

REGISTRATION NUMBER

NCT03757286. Registration date: 28/11/2018.

A Simplified Approach to Jaw-in-a-Day Using a Preassembled Prosthesis: Lowering the Barrier to Entry

Fibula flap reconstruction with primary dental implant placement has been established as a successful procedure for composite mandibular defects. When using virtual surgical planning, these techniques typically require additional personnel and materials preoperatively and intraoperatively to fabricate occlusal-based guidance and prosthesis. The authors present a technique utilizing a custom-made implant-supported prosthesis completed before surgery that greatly reduces lead time and needed resources. The authors follow the established workflow of segmental mandibulectomy and fibula flap reconstruction using premanufactured cutting guides and placement of dental implants. Cylindrical holes along the implant axes are included in the printed surgical model provided by the guide manufacturer. Acrylic resin and abutments are added to the model to a positioning stent for use during surgery that does not require intraoperative modification before fibula inset. This ensures optimal position for facial esthetics and fixed dental rehabilitation. The presented technique uses printed models already provided by the guide manufacturer, reducing preparation time and requiring fewer personnel and materials intraoperatively. This is an approach to the jaw-in-a-day procedure with a lower barrier to entry that may be used by new craniofacial teams.

Vascularized Fibula TMJ Reconstruction: A Report of Five Cases featuring Computerized Patient-specific Surgical Planning

BACKGROUND

Mandibular defects involving the condyle represent a complex reconstructive challenge for restoring proper function of the temporomandibular joint because it requires precise bone graft alignment, or alloplastic materials, for complete restoration of joint function. The use of computerized patient-specific surgical planning (CPSSP) technology can aid in the anatomic reconstruction of mandibular condyle defects with a vascularized free fibula flap without the need for additional adjuncts. The purpose of this study was to analyze clinical and functional outcomes after reconstruction of mandibular condyle defects using only a free fibula graft with the assistance of virtual surgery techniques.

METHODS

A retrospective review was performed to identify all patients who underwent mandibular reconstruction utilizing CPSSP with only a free fibula flap without any temporomandibular joint adjuncts after a hemimandibulectomy with total condylectomy.

RESULTS

From 2018 to 2021, five patients underwent reconstruction of mandibular defects involving the condyle with CPSSP technology and preservation of the native temporomandibular articulating disk. The average age was 62 years (range, 44-73 years). The average follow-up period was 29.2 months (range, 9-46 months). Flap survival was 100% (N = 5). The maximal interincisal opening range for all patients was 22-45 mm with no lateral deviation or subjective joint pain. No patients experienced progressive joint hypomobility or condylar migration.

CONCLUSION

The use of CPSSP technology can aid in the anatomic reconstruction of mandibular condyle defects with a vascularized free fibula flap through precise planning and intraoperative manipulation with optimal functional outcomes.

Osseous Union after Mandible Reconstruction with Fibula Free Flap Using Manually Bent Plates vs. Patient-Specific Implants: A Retrospective Analysis of 89 Patients

The aim of this monocentric, retrospective clinical study was to evaluate the status of osseous union in uni- and poly-segmental mandible reconstructions regarding conventional angle-stable manually bent osteosynthesis plates (Unilock 2.0 mm) versus titan laser-melted PSI patient-specific implant’s (PSI). The clinical impact of PSI’s high stiffness fixation methods on bone healing and regeneration is still not well addressed. The special interest was in evaluating the ossification of junctions between mandible and fibula and between osteotomized fibula free flap (FFF) segments. Panoramic radiograph (OPT), computed tomography (CT) scans, or cone-beam CTs (CBCT) of patients who underwent successful FFF for mandible reconstruction from January 2005 to December 2020 were analyzed. A total number of 89 cases (28 females (31.5%), 61 males (68.5%), mean age 58.2 ± 11.3 years, range: 22.8–82.7 years) fulfilled the chosen inclusion criteria for analysis (conventional: n = 44 vs. PSI: n = 45). The present study found an overall incomplete ossification (IOU) rate of 24.7% (conventional: 13.6% vs. PSI: 35.6%; p = 0.017) for mandible to fibula and intersegmental junctions. Between osteotomized FFF segments, an IOU rate of 16% was found in the PSI-group, while no IOU was recorded in the conventional group (p = 0.015). Significant differences were registered for IOU rates in poly-segmental (p = 0.041), and lateral (p = 0.016) mandibular reconstructions when PSI was used. Multivariate logistic regression analysis identified plate exposure and type of plate used as independent risk factors for IOU. Previous or adjuvant radiotherapy did not impact incomplete osseous union in the evaluated study sample. PSI is more rigid than bent mini-plates and shields functional mechanical stimuli, and is the main reason for increasing the rate of incomplete ossification. To enhance the functional stimulus for ossification it has to be discussed if patient-specific implants can be designed to be thinner, and should be divided into segmental plates. This directs chewing forces through the bone and improves physiological bone remodeling.

Impact of intraoperative ischemia time on acute complications of head and neck microvascular free tissue transfer: A systematic review and meta-analysis

BACKGROUND

To evaluate the relationship between intraoperative ischemia time with acute microvascular free tissue transfer (MFTT) complications in head and neck reconstruction.

METHODS

A systematic review using PRISMA guidelines was performed. Inclusion encompassed all available studies published and indexed using PubMed, Medline, and Embase. Meta-analyses were performed using the Cochrane Review Manager tool. Methodological Index for Non-Randomized Studies (MINORS), the Revised Cochrane risk-of-bias tool for randomized trials, and the NIH Study Quality Assessment Tool for non-randomized prospective studies.

RESULTS

A total of 430 citations were reviewed. 25 were included in our overall qualitative analysis, and 14 for meta-analysis. When comparing ischemia times for flaps with and without complications, no significant difference was observed (p = 0.98). Additionally, in a separate cohort, no significant effect was realized when correlating ischemia time to overall rates and total complications.

CONCLUSION

Ischemia time was not significantly different between those with and without acute flap complications.

Comparing the use of conventional and three-dimensional printing (3DP) in mandibular reconstruction

Background

There are a number of clinical disorders that require mandibular reconstruction (MR). Novel three-dimensional (3D) printing technology enables reconstructions to be more accurate and beneficial to the patient. However, there is currently no evidence identifying which techniques are better suited for MR, based on the type of clinical disorder the patient has. In this study, we aim to compare 3D techniques with conventional techniques to identify how best to reconstruct the mandible based on the clinical cause that necessitates the reconstructive procedure: cancerous or benign tumours, clinical disorders, infection or disease and trauma or injury.

Methods

PubMed, Scopus, Embase and Medline were searched to identify relevant papers that outline the clinical differences between 3D and conventional techniques in MR. Data were evaluated to provide a clear outline of suitable techniques for surgery.

Results

20 of 2749 papers met inclusion criteria. These papers were grouped based on the clinical causes that required MR into four categories: malignant or benign tumour resection; mandibular trauma/injury and other clinical disorders.

Conclusions

The majority of researchers favoured 3D techniques in MR. However, due to a lack of standardised reporting in these studies it was not possible to determine which specific techniques were better for which clinical presentations.

The Role of 3D Printing in Planning Complex Medical Procedures and Training of Medical Professionals-Cross-Sectional Multispecialty Review

Medicine is a rapidly-evolving discipline, with progress picking up pace with each passing decade. This constant evolution results in the introduction of new tools and methods, which in turn occasionally leads to paradigm shifts across the affected medical fields. The following review attempts to showcase how 3D printing has begun to reshape and improve processes across various medical specialties and where it has the potential to make a significant impact. The current state-of-the-art, as well as real-life clinical applications of 3D printing, are reflected in the perspectives of specialists practicing in the selected disciplines, with a focus on pre-procedural planning, simulation (rehearsal) of non-routine procedures, and on medical education and training. A review of the latest multidisciplinary literature on the subject offers a general summary of the advances enabled by 3D printing. Numerous advantages and applications were found, such as gaining better insight into patient-specific anatomy, better pre-operative planning, mock simulated surgeries, simulation-based training and education, development of surgical guides and other tools, patient-specific implants, bioprinted organs or structures, and counseling of patients. It was evident that pre-procedural planning and rehearsing of unusual or difficult procedures and training of medical professionals in these procedures are extremely useful and transformative.

A Comparative Study of Analog Preoperative Planning Versus Virtual Preoperative Planning for Mandibular Reconstruction With Fibula Free Flap

ABSTRACT

Mandibular reconstruction is a challenging procedure, especially in cancer patients with defects that are greater than 6 cm. Free vascularized fibular flap is the gold standard treatment in these cases since it allows three-dimensional restoration of the lost segments after ablative surgery in addition to providing the possibility of a subsequent implant-supported rehabilitation improving the functional and aesthetic outcomes of the surgery.To obtain accurate results, preoperative planning must be done with detail. Approaches for the preoperative planning include both the conventional analog planning and the virtual planning that are valid alternatives in meeting the trans-surgical requirements.This study makes a comparative analysis of 2 clinical cases with a diagnosis of squamous cell carcinoma that were reconstructed using a vascularized fibular free flap. The first case was planned using the conventional analog method whereas the second case was planned using the virtual planning approach.The impact of virtual planning and conventional analog planning on preoperative planning time, ischemia period, and total surgical time is analyzed according to the experience obtained in the cases presented. In addition, the authors described the technique used for each planning method along with a literature review in which the results are contrasted and discussed.

Current Therapeutic Strategies in Patients with Oropharyngeal Squamous Cell Carcinoma: Impact of the Tumor HPV Status

Simple Summary

Contrary to other head and neck subsites, oropharyngeal squamous cell carcinoma (OPSCC) has shown a considerable increase in incidence over the past 20 years. This growing incidence is largely due to the increasing place of human papillomavirus (HPV)-related tumors. HPV-positive and HPV-negative OPSCC are two distinct entities with considerable differences in terms of treatment response and prognosis. However, there are no specific recommendations yet in the therapeutic management of OPSCC patients according to their tumor HPV-status. The aim of this review is therefore to discuss the therapeutic management of patients with OPSCC and the impact of HPV status on treatment selection.

Abstract

Since there is no published randomized study comparing surgical and non-surgical therapeutic strategies in patients with oropharyngeal squamous cell carcinoma (OPSCC), the therapeutic management of these patients remains highly controversial. While human papillomavirus (HPV)-positive and HPV-negative OPSCC are now recognized as two distinct diseases with different epidemiological, biological, and clinical characteristics, the impact of HPV status on the management of OPSCC patients is still unclear. In this review, we analyze the current therapeutic options in patients with OPSCC, highlighting the most recent advances in surgical and non-surgical therapies, and we discuss the impact of HPV status on the therapeutic strategy.

Impact of Planning Method (Conventional versus Virtual) on Time to Therapy Initiation and Resection Margins: A Retrospective Analysis of 104 Immediate Jaw Reconstructions

Simple Summary

Computer-aided design and manufacturing of osseous reconstructions are currently widely used in jaw reconstructive surgery, providing an improved surgical outcome and decreased procedural stumbling block. However, data on the influence of planning time on the time-to-surgery initiation and resection margin are missing in the literature. This retrospective, monocentric study compares process times from the first patient contact in hospital, time of in-house or out-of-house biopsy for tumor diagnosis and surgical therapy of tumor resection, and immediate reconstruction of the jaw with free fibula flaps (FFF). Two techniques for reconstruction are used: Virtual surgical planning (VSP) and non-VSP. A total of 104 patients who underwent FFF surgery for immediate jaw reconstruction from 2002 to 2020 are included. The study findings fill the gaps in the literature and obtain clear insights based on the investigated study subjects.

Abstract

Virtual surgical planning (VSP) and patient-specific implants are currently increasing for immediate jaw reconstruction after ablative oncologic surgery. This technique contributes to more accurate and efficient preoperative planning and shorter operation time. The present retrospective, single-center study analyzes the influence of time delay caused by VSP vs. conventional (non-VSP) reconstruction planning on the soft and hard tissue resection margins for necessary oncologic safety. A total number of 104 cases of immediate jaw reconstruction with free fibula flap are included in the present study. The selected method of reconstruction (conventionally, non-VSP: n = 63; digitally, VSP: n = 41) are analyzed in detail. The study reveals a statistically significant (p = 0.008) prolonged time to therapy initiation with a median of 42 days when the VSP method compared with non-VSP (31.0 days) is used. VSP did not significantly affect bony or soft tissue resection margin status. Apart from this observation, no significant differences concerning local tumor recurrence, lymph node, and distant metastases rates are found according to the reconstruction method, and affect soft or bone tissue resection margins. Thus, we conclude that VSP for immediate jaw reconstruction is safe for oncological purposes.

Short and long-term outcomes of three-dimensional printed surgical guides and virtual surgical planning versus conventional methods for fibula free flap reconstruction of the mandible: Decreased nonunion and complication rates

BACKGROUND

To determine whether virtual surgical planning and three-dimensional printed cutting guides (3D/VSP) improved radiographic bone union compared to conventional methods (CM) in fibula free flap (FFF) reconstruction of the mandibles.

METHODS

Retrospective study from the years 2000-2018 at a tertiary hospital. Osseous union was evaluated by a radiologist blinded to each patient's treatment.

RESULTS

Two hundred sixty patients who underwent FFF tissue transfer, 28 with VSP and 3D cutting guides. Bony union was not achieved in 46 (20%) patients who underwent CM compared to 1 (4%) of patients with VSP and guides (p = 0.036). FFF complication was significantly higher in CM with 87 patients (38%) compared to three patients (11%) in 3D/VSP (p = 0.005). Median time to bony union for patients who underwent CM was 1.4 years compared to 0.8 years in 3D/VSP.

CONCLUSIONS

3D/VSP reduced the rate of radiographic nonunion and flap-related complications in FFF reconstruction for mandibular defects.

Maxillofacial reconstruction with prefabricated prelaminated osseous free flaps

BACKGROUND

The prefabricated fibula flap is an advanced method of occlusal-based reconstruction that combines placement of osseointegrated dental implants with prelamination, using a split skin graft on the fibula, weeks prior to the definitive reconstruction. This approach is resource intensive but has several advantages including eliminating the delay from reconstruction to dental rehabilitation.

METHODS

A retrospective cohort study of all prefabricated fibula flaps used for mandible and maxillary reconstruction from 2012 to 2020 was performed. Outcome measures were implant survival, implant utilization and functional dental rehabilitation.

RESULTS

A total of 17 prefabricated fibula flaps were performed including two analogue and 15 digital plans. There were nine maxillary and eight mandibular reconstructions, of which 11 were primary and seven were secondary. There were no free flap failures. A total of 65 implants were placed (average 3.8, median 3 implants). There was one implant failure at 6 years giving a 1.5% failure rate. There was 91% implant utilization and 94% functional dental rehabilitation.

CONCLUSION

The prefabricated fibula flap provides outstanding dental rehabilitation in well-selected patients.

Advances in Oromandibular Reconstruction with Three-Dimensional Printing

The mandibular structures are a complex anatomical structure that is fundamental to many physiological and homeostatic functions. It may be involved in many pathological processes that require partial or complete removal. When this happens, reconstruction is mandatory to improve cosmetic outcome with its effect on social interaction as well as to provide an opportunity for complete dental rehabilitation with restoration of all physiological functions. This article will review the different reconstructive options available for complex defects of the mandibular complex. It will highlight the surgical options available to maximize functional restoration. Finally, it will discuss computer modeling to optimize reconstructive planning.

Initial Experience Using 3-Dimensional Printed Models for Head and Neck Reconstruction in Haiti

This report describes the first use of a novel workflow for in-house computer-aided design (CAD) for application in a resource-limited surgical outreach setting. Preoperative computed tomography imaging obtained locally in Haiti was used to produce rapid-prototyped 3-dimensional (3D) mandibular models for 2 patients with large ameloblastomas. Models were used for patient consent, surgical education, and surgical planning. Computer-aided design and 3D models have the potential to significantly aid the process of complex surgery in the outreach setting by aiding in surgical consent and education, in addition to expected surgical applications of improved anatomic reconstruction.

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.

Evaluation of the Accuracy of Three-Dimensional Virtual Surgical Planning for Reconstruction of Mandibular Defects Using Free Fibular Flap

BACKGROUND

Mandibular reconstruction is considered one of the most complex reconstructive surgeries in the field of craniomaxillofacial surgery. With the introduction of microvascular reconstructive surgery, free fibula flap become the gold standard for reconstruction of mandibular defects. For optimum restoration of the patient's esthetics and function, the free fibular flap should be recontoured to follow the natural premorbid state of the mandible. Virtual surgical planning using preoperative computed tomographic (CT) data can be rendered into 3-dimensional (3D) model for digitalized simulation of the bony resection and reconstruction with reported high accuracy.

METHODS

Ten patients were included in the study for delayed mandibular reconstruction using free fibular flap. For all the patients, preoperative CT scan for the skull and lower limbs were obtained and integrated into the software for virtual planning and guides fabrications. Postoperative CT was obtained and rendered 3D model to be superimposed on the preoperative record for assessment of the virtual planning accuracy by different linear and angular measurements.

RESULTS

No statistically significant difference was found between virtual group and postoperative group where P = 0.067, regarding average of linear measurements of all patients. Statistically significant difference was found between virtual group and postoperative group in measurements from axial plane where P = 0.004. No statistically significant difference was found between virtual group and postoperative group where P = 0.723, regarding angles between fibular segments.

CONCLUSION

Virtual surgical planning for mandibular reconstruction offers high reproducibility and precision, reducing the side errors, besides its time saving advantage for both the operator and the patient.

Predictive factors for prolonged operative time in head and neck patients undergoing free flap reconstruction

PURPOSE

Defining the predictive factors associated with prolonged operative time may reduce post-operative complications, improve patient outcomes, and decrease cost of care. The aims of this study are to 1) analyze risk factors associated with prolonged operative time in head and neck free flap patients and 2) determine the impact of lengthier operative time on surgical outcomes.

METHODS

This retrospective cohort study evaluated 282 head and neck free flap reconstruction patients between 2011 and 2013 at a tertiary care center. Perioperative factors investigated by multivariate analyses included gender, age, American Society of Anesthesiologists class, tumor subsite, stage, flap type, preoperative comorbidities, and perioperative hematocrit nadir. Association was explored between operative times and complications including flap take back, flap survival, transfusion requirement, flap site hematoma, and surgical site infection.

RESULTS

Mean operative time was 418.2 ± 88.4 (185-670) minutes. Multivariate analyses identified that ASA class III (beta coefficient + 24.5, p = .043), stage IV tumors (+34.8, p = .013), fibular free flaps (-44.8, p = .033 for RFFF vs. FFF and - 67.7, p = .023 for ALT vs FFF) and COPD (+36.0, p = .041) were associated with prolonged operative time. History of CAD (-43.5, p = .010) was associated with shorter operative time. There was no statistically significant association between longer operative time and adverse flap outcomes or complications.

CONCLUSION

As expected, patients who were medically complex, had advanced cancer, or underwent complex flap reconstruction had longer operative times. Surgical planning should pay special attention to certain co-morbidities such as COPD, and explore innovative ways to minimize operative time. Future research is needed to evaluate how these factors can help guide planning algorithms for head and neck patients.

Effectiveness of computer-assisted virtual planning, cutting guides and pre-engineered plates on outcomes in mandible fibular free flap reconstructions: a systematic review protocol

OBJECTIVE

The objective of this review is to synthesize the best available evidence on the outcomes of mandibular fibular free flap (MFFF) reconstructions using computer-assisted techniques versus traditional freehand techniques.

INTRODUCTION

Fibular free flaps are the most commonly used free flap for mandible reconstruction and are considered best practice for mandible reconstructions following resection of head and neck cancers. There are several reported advantages of computer-assisted MFFF reconstructions, including increased accuracy, decreased operation time, decreased ischemia time, decreased overall cost and improved patient outcomes. It is important to assess the advantages and potential harms of these techniques in a systematic review.

INCLUSION CRITERIA

Eligible studies will consider patients of all ages undergoing MFFF reconstruction. Studies will compare computer-assisted techniques to traditional freehand techniques for the primary outcomes of flap failure, patient-reported outcomes and bony resection margin status. Studies published in English from 2008 will be included. Experimental, quasi-experimental, prospective and retrospective cohort, case-control and analytical cross-sectional studies will be considered.

METHODS

MEDLINE, Embase, Scopus and the Cochrane Central Register of Controlled Trials will be searched. Gray literature sources will include Google Scholar and the World Health Organization International Clinical Trials Registry Platform. Two independent reviewers will screen titles and abstracts, assess full-text papers against the inclusion criteria, evaluate methodological quality using standardized critical appraisal instruments and extract data using a customized form. If possible, data will be pooled for statistical meta-analysis, and a Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Summary of Findings will be presented.

Virtual surgical planning in fibula free flap head and neck reconstruction: A systematic review and meta-analysis

BACKGROUND

The traditional approach to head and neck reconstruction is considered challenging, requiring a subjective assessment of an often-complex defect followed by careful modelling of a bony flap to match this. The introduction of Virtual Surgical Planning (VSP) has provided the surgeon with a means to increase efficiency, precision and overall patient outcomes. This study aims to compare VSP and traditional head and neck reconstructions utilising fibula free flaps with regards surgical efficiency and patient outcomes.

METHODS

A systematic search of the PubMed and Medline databases was performed from the date of their inception through to August 2018 to evaluate and compare VSP and non-VSP cohorts in the context of fibula free flap head and neck reconstruction. Primary comparative outcomes included operative and ischaemic time, with secondary outcomes including complications rates, measures of accuracy and financial benefits.

RESULTS

One hundred and fifty-three articles were identified. Twenty-three articles were included in the review, comprising a total of 713 patients. VSP was associated with significantly decreased intraoperative time (Standardised Mean Difference -1.01; 95% CI -1.23 to 0.80; p = 0.000) and ischaemic time (Standardised Mean Difference -1.55; 95% CI -1.87 to -1.23, p = 0.002). VSP was also associated with reduced orthognathic deviation from an ideal outcome when compared to conventional techniques. No statistically significant differences in complication rates between conventional and VSP techniques were identified.

CONCLUSION

The results of this meta-analysis suggests that VSP confers significant benefits with respect to improved orthognathic accuracy, ischaemic times and intraoperative times without any significant increase in complications. Recommendations for ongoing research are suggested.

In house virtual surgery and 3D complex head and neck reconstruction

Background

3-Dimensional (3D) printing can be applied to virtual planning and creation of surgical guides for mandibular reconstruction. Such systems are becoming increasingly prevalent in head and neck reconstruction. However, third party access to this technology is costly and removes the opportunity to design, create, and modify the bony reconstructions, as third party technology is a black box. This series is a pilot study to document the feasibility of an in-house software tool. The objectives of this study are to describe the design of an automated in house system and assess the accuracy of this in house automated software tool for mandibular reconstruction in a simulated environment.

Methods

Software was written to automate the preoperative planning and surgical guide creation process. In a simulation lab, Otolaryngology residents were tasked with resecting and reconstructing a simulated mandible using the 3D-printed cutting guides. A control group of residents performed resection and reconstruction using the traditional method without cutting guides. T-test analysis was performed to compare specific aspects of the final reconstructions including: change from native mandibular width and projection, segment gap distance, and reconstruction time.

Results

Mandibular reconstruction was successful in all participants using the 3D printed system.

The guided group performed significantly better on the measurement of change in Mandibular overlap, projection, segment gap volume. There was a non-significant trend towards better mandibular width and operative time for the guided group.

Conclusions

This study confirms functionality and feasibility of using an in house automated software for planning and creating surgical guides.

Impact of 3D virtual planning on reconstruction of mandibular and maxillary surgical defects in head and neck oncology

PURPOSE OF REVIEW

This review describes the advances in 3D virtual planning for mandibular and maxillary reconstruction surgical defects with full prosthetic rehabilitation. The primary purpose is to provide an overview of various techniques that apply 3D technology safely in primary and secondary reconstructive cases of patients suffering from head and neck cancer.

RECENT FINDINGS

Methods have been developed to overcome the problem of control over the margin during surgery while the crucial decision with regard to resection margin and planning of osteotomies were predetermined by virtual planning. The unlimited possibilities of designing patient-specific implants can result in creative uniquely applied solutions for single cases but should be applied wisely with knowledge of biomechanical engineering principles.

SUMMARY

The high surgical accuracy of an executed 3D virtual plan provides tumor margin control during ablative surgery and the possibility of planned combined use of osseus free flaps and dental implants in the reconstruction in one surgical procedure. A thorough understanding of the effects of radiotherapy on the reconstruction, soft tissue management, and prosthetic rehabilitation is imperative in individual cases when deciding to use dental implants in patients who received radiotherapy.

Accuracy of computer-assisted surgery in mandibular reconstruction: A systematic review

Computer-assisted surgery (CAS) for mandibular reconstruction was developed to improve conventional treatment methods. In the past years, many different software programs have entered the market, offering numerous approaches for preoperative planning and postoperative evaluation of the CAS process of mandibular reconstruction. In this systematic review, we reviewed planning and evaluation methods in studies that quantitatively assessed accuracy of mandibular reconstruction performed with CAS. We included 42 studies describing 413 mandibular reconstructions planned and evaluated using CAS. The commonest software was Proplan/Surgicase CMF (55%). In most cases, the postoperative virtual 3-dimensional model was compared to the preoperative 3-dimensional model, revised to the virtual plan (64%). The commonest landmark for accuracy measurements was the condyle (54%). Accuracy deviations ranged between 0 mm and 12.5 mm and between 0.9° and 17.5°. Because of a lack of uniformity in planning (e.g., image acquisition, mandibular resection size) and evaluation methodologies, the ability to compare postoperative outcomes was limited; meta-analysis was not performed. A practical and simple guideline for standardizing planning and evaluation methods needs to be considered to allow valid comparisons of postoperative results and facilitate meta-analysis in the future.

Prefabricated fibula free flap with dental implants for mandibular reconstruction

Free fibula transplant is routinely used for mandibular reconstruction in head and neck cancer. Dental rehabilitation, the objective of mandibular reconstruction, requires the use of dental implants as supports for fixed or removable dentures. Positioning of fibular bone grafts and implants determines implant osseointegration and the possibilities of dental rehabilitation. Prefabrication of a fibula free flap with dental implants prior to harvesting as a free flap can promote implant osseointegration. The position of the implants must then be precisely planned. Virtual surgery and computer-assisted design and prefabrication techniques are used to plan the reconstruction and then reproduce this planning by means of tailored fibula and mandible cutting guides, thereby ensuring correct positioning of fibular bone fragments and implants. The prefabricated fibula free flap technique requires two surgical procedures (prefabrication and flap transfer) and precise preoperative planning. Prefabricated fibula free flap with dental implants, by improving the quality of osseointegration of the implants before flap transfer, extends the possibilities of prosthetic rehabilitation in complex secondary mandibular reconstructions.

Enabling personalized implant and controllable biosystem development through 3D printing

The impact of additive manufacturing in our lives has been increasing constantly. One of the frontiers in this change is the medical devices. 3D printing technologies not only enable the personalization of implantable devices with respect to patient-specific anatomy, pathology and biomechanical properties but they also provide new opportunities in related areas such as surgical education, minimally invasive diagnosis, medical research and disease models. In this review, we cover the recent clinical applications of 3D printing with a particular focus on implantable devices. The current technical bottlenecks in 3D printing in view of the needs in clinical applications are explained and recent advances to overcome these challenges are presented. 3D printing with cells (bioprinting); an exciting subfield of 3D printing, is covered in the context of tissue engineering and regenerative medicine and current developments in bioinks are discussed. Also emerging applications of bioprinting beyond health, such as biorobotics and soft robotics, are introduced. As the technical challenges related to printing rate, precision and cost are steadily being solved, it can be envisioned that 3D printers will become common on-site instruments in medical practice with the possibility of custom-made, on-demand implants and, eventually, tissue engineered organs with active parts developed with biorobotics techniques.