Reconstruction of large defects postmandibulectomy for oral cancer using plates and myocutaneous flaps: a long-term follow-up

Case report of a patient with mandibulectomy followed up for 11 years

Mandibular deviation and rotation following mandibulectomy can significantly impact oral function and quality of life. The postoperative course of a 57-year-old patient who underwent mandibulectomy for oral cancer and findings over 11 years of follow-up observation to monitor changes in the mandibular position are described here. Based on the observations, it is important to raise awareness regarding the necessity of continued monitoring of mandible position and regular adjustments of prostheses for patients who have undergone mandibulectomy.

Use of reconstruction plates prebent on three-dimensional models to reduce the complications of mandibular reconstruction

Background/purpose

Though the gold standard method for mandible reconstruction of the defect from segmental mandibulectomy is by osseous flap or graft, using reconstruction plates is still indicated in some cases. Traditionally, the plate is bended immediately after the segmental mandibulectomy by freehand. However, it's difficult to fit well to the original position of mandible, which may result in more complications. This study therefore aimed to investigate whether using prebent plates on computer-aided 3D printing models could reduce the complication rate.

Materials and methods

Patients who received mandible reconstruction by reconstruction plate from 2018 to 2022 were enrolled and evaluated in this study. The data, including demographics, indications for surgery, pre-existed preoperative and postoperative therapies, classification of defects, and postoperative outcomes were collected and analyzed.

Results

A total of 52 patients were enrolled in our study. The prebent group exhibited a significantly lower complication rate than that of the immediately bent group (P = 0.012). Other risk factors of plate complications included postoperative adjuvant radiotherapy (P = 0.017) and previous surgery (P = 0.047). The complication-free survival rate was also better in the prebent group in a 3-year follow-up period (P = 0.012).

Conclusion

Prebent plates on computer-aided printing models proved to be an effective approach to reduce the complications for mandibular reconstruction in segmental mandibulectomy.

Bone reconstruction of extensive maxillomandibular defects in adults

Reconstruction of significant maxillomandibular defects is a challenge that has been much discussed over the last few decades. Fundamental principles were developed decades ago (bone bed viability, graft immobilization). Clinical decision-making criteria are highly relevant, including local/systemic factors and incision designs, the choice of material, grafting technique, and donor site morbidity. Stabilizing particulated grafts for defined defects-that is, via meshes or shells-might allow significant horizontal and vertical augmentation; the alternatives are onlay and inlay techniques. More significant defects might require extra orally harvested autologous bone blocks. The anterior iliac crest is often used for nonvascularized augmentation, whereas more extensive defects often require microvascular reconstruction. In those cases, the free fibula flap has become the standard of care. The development of alternatives is still ongoing (i.e., alloplastic reconstruction, zygomatic implants, obturators, distraction osteogenesis). Especially for these complex procedures, three-dimensional planning tools enable facilitated planning and a surgical workflow.

A novel alloplastic grid reconstruction plate for the mandible - Retrospective comparative clinical analysis of failure rates and specific complications

PURPOSE

This study aimed to investigate the effect of three different osteosynthesis plate systems on failure rates and complications after continuity-interrupting mandibular resections with alloplastic reconstructions.

MATERIALS AND METHODS

Records of respective patients from 2010 to 2020 were analyzed retrospectively. The analyses included the osteosynthesis plate type (2.4 MANDIBULAR (RP1: MANDIBULAR [Medicon®, Tuttlingen, Germany]; RP2: Modus® Reco 2.5 [Medartis®, Basel, Switzerland]; and RP3: Modus 2 Mandible [Medartis®, Basel, Switzerland]), extent & location of the defect, age, sex, radiotherapy, and nicotine abuse. In case of failure, timepoint, and the problem, namely oral/extraoral dehiscence, screw loosening, and plate fractures that led to removal, were analyzed. Complications were classified according to Clavien-Dindo system.

RESULTS

A total of 136 patients were included. The mean follow-up time was 18 ± 26 months. Survival rates after 1, 2, and 5 years were 69.9%, 66.9%, and 64.7%, respectively. Although survival was not significantly associated with the reconstruction system, the most frequent complications were seen in cases of RP1 & RP2 when compared to RP3 (p = 0.033). In brief, dehiscences were seen significantly less often in cases of RP3 (12.5%) when compared to RP1 (44.7%) and RP2 (26.9%; p = 0.024). Fractures of the osteosynthesis systems occurred in 3 of 4 cases (75%) with RP1, in 1 of 4 cases (25%) using RP2, and in no single case using the RP3 system (p = 0.03). Most of the observed complications occurred up to 12 months postoperatively. A total plate survival rate of 64.7% and a total plate complication rate of 47.8% were seen.

CONCLUSION

In conclusion, it seems that RP3 should be preferred over RP1 and RP2 regarding failure rates and complications.

Patient Specific Alloplastic Implant Reconstruction of Mandibular Defects-Safe Practice Recommendations and Guidelines

Mandibular continuity defects are commonly seen after tumor resection, osteomyelitis or maxillofacial trauma. Three-dimensional reconstruction of these mandibular segmental defects is critical for proper mandibular functioning and esthetics. Various methods used to reconstruct such defects include bridging reconstruction plates, modular endoprosthesis, non-vascularized and vascularized bone grafting with stock reconstruction plate or patient specific implants (PSI) and tissue engineering bone transfer. But in the recent years, literature documents use of PSI only alloplastic reconstruction as an alternate to microvascular bone flap reconstruction. Representative cases enumerate current practice of 'patient specific implant only' mandibular reconstruction and its pitfalls. This article discusses current status of literature on PSI's, choice of indications for 'PSI only' mandibular reconstruction and also proposes guidelines for safe practice of patient specific implant reconstruction of mandible.

Plate-related complication and health-related quality of life after mandibular reconstruction by fibula flap with reconstruction plate or miniplate versus anterolateral thigh flap with reconstruction plate

BACKGROUND

Plate-related complications are major long-term complications in mandible reconstruction. There are controversies regarding the use of a reconstruction plate versus miniplates and a bone flap versus a soft tissue flap with a bridging plate. Direct comparisons of a fibula flap and an anterolateral thigh flap, the applicability between a reconstruction plate and miniplate, and the correlation between plate-related complications and quality of life remain unclarified. Therefore, this study aimed to the explore complications of different flaps and plates and how they impact the patients' quality of life.

METHODS

We retrospectively reviewed the medical records of a total of 205 patients aged >18 years who underwent segmental mandibulectomy and reconstruction using fibula flap with reconstruction plate (FR; n = 86), fibula flap with miniplate (FM; n = 61), and anterolateral thigh flap with reconstruction plate (AR; n = 58) due to cancer ablation, osteoradionecrosis, or benign tumor excision between August 2010 and December 2019. Data on characteristics, complications, and health-related quality of life were collected and analyzed.

RESULTS

The plate-related complication rate was the highest in the AR group (37.9%), then in the FR group (25.6%), and was the lowest in the FM group (13.1%; p = 0.0079). The plate exposure rate was the highest in the AR group (24.1%), then in the FR group (15.7%), and was the lowest in the FM group (4.9%; p = 0.0128). The plate fracture and dislodge rates for the AR group were both higher than those for the FR and FM groups (24.1% versus 9.3% versus 9.8%, respectively; p = 0.023). The AR group had worse complication-free survival (hazard ratio [HR]: 3.61, 95% CI: 1.99-6.56, and p < 0.0001) than the FR and FM groups. Osteoradionecrosis (HR: 6.19, 95% CI: 2.11-18.21, and p = 0.0009) and postoperative radiotherapy (HR: 2.87, 95% CI: 1.34-6.12, and p = 0.0402) were both independent adverse factors for complication-free survival, whereas patient treated primarily (HR: 0.35, 95% CI: 0.17-0.73, and p = 0.0048) was an independent protective factor. Plate-related complication negatively impacted the quality of life based on pain scores (β: -0.56, SE: 0.26, and p = 0.034).

CONCLUSIONS

Using a fibular flap fixed with miniplates and avoiding the use of a reconstruction plate may yield a reduced plate exposure rate and better health-related quality of life, particularly for patients with osteoradionecrosis or those who need postoperative radiotherapy.

Hemi-mandibulectomy without bony reconstruction: A case report of mandibular metastasis from a silent differentiated papillary thyroid cancer

Introduction

Case presentation

Discussion

•

Mandibulectomy without reconstruction can be performed for selected cases.

•

Metastasis to the mandible from differentiated thyroid cancer is rare.

•

Silent thyroid cancer can be manifested as mandible metastasis.

Quantification of the Bimodal Plate-Specific Complication Profile Associated With Reconstruction of Segmental Mandibular Defects With Reconstruction Plate and Soft Tissue Flap: Evidence From Systematic Review

ABSTRACT

Reconstruction of segmental mandibular defects with a mandibular reconstruction plate and separate soft tissue flap can be indicated in certain patients. Whilst this technique can provide acceptable results, its exact longevity and timing of associated complications is poorly understood. This study was designed to quantify and plot in time the complication profile associated with this technique of mandibular reconstruction.A search of the Medline and PubMed Central databases was conducted using the terms "Mandibulectomy" and "Reconstruction Plate." Articles reporting total number of plate extrusions and fractures and their postoperative timing were included.Nine articles were included, representing 265 patients with mandibulectomy defects reconstructed using mandibular reconstruction plates. Of these, 135 were male (62%) and 82 were female (38%). The mean age was 59 years. The predominant pathology was oral cavity Squamous Cell Carcinoma (SCC) (80%). Seventy-three patients (28%) experienced complications (mean follow-up: 24 months), with median time to complication of 3 months. Forty-three plate extrusions (16%), 20 plate fractures (8%) and 10 cases of loosened screws (4%) were reported. A bimodal temporal distribution of complications was found.Overall, a plate-specific complication rate of 28% was found, confirming a higher incidence of complications in comparison to osseous free flap reconstruction. These occur over a bimodal time distribution, with extrusion occurring earlier than fracture. Interference with speech, swallow and dental rehabilitation, and delay of adjuvant therapy are potential consequences. These findings indicate that patients may be better served by more complex reconstructive procedures, to minimize exposure to a frequent and prolonged complication profile.

Mandibular reconstruction system reliability analysis using probabilistic finite element method

The aim of this study was to design for mandibular reconstruction of large lateral defect with minimum target reliability with designated confidence interval under bite force range of 300 ± 102 N. The performance of the models has been evaluated by numerical analysis considering the uncertainty of input parameters. Computer-Aided design was used to develop the models of three designs according to the patient's anatomy and to achieve to near symmetry of the mandible. Stress-strength modeling was utilized for the probabilistic physics of failure analysis under assumption of a quasi-static load. Monte-Carlo simulation was also applied for probabilistic finite element analysis and reliability assessment. The sensitivity analysis of the models was developed to reflect the significance of the variables in the models. The deterministic stress analysis shows that the highest stress and the second maximum stress are 110 MPa and 85 MPa for cortical bone around the screws, respectively. Also, it is determined that the maximum plate stress of the titanium conventional plate model is 580 MPa. The reconstruction system success rate was improved in all models by observing the anatomy of the patient's mandible in the plate designs by computer-aided design and additive manufacturing techniques. Based on the results, the reliability of plate strength and pull-out screws strength are 99.99% and 96.71% for the fibula free flap model, respectively, and 99.99% and 94.17%, respectively, for the customized prosthesis model. Probability sensitivity factors showed that uncertainty in the elastic modulus of the cortical bone has the greatest effect on the probability of screws loosening.

Evaluating the use of anterolateral thigh flaps to prevent reconstruction plate exposure in patients with oral cancer

OBJECTIVE

Plate exposure remains one of the most serious complications of oromandibular reconstruction. The purpose of this study was to investigate the effect of wrapping reconstruction plates with anterolateral thigh (ALT) free flaps as a way to prevent plate exposure.

STUDY DESIGN

A total of 91 patients with composite oromandibular defects who underwent surgical reconstruction using a reconstruction plate in conjunction with an ALT musculocutaneous flap were recruited. The participants were divided into 2 groups, based on whether the plate was wrapped with or covered by the ALT flap.

RESULTS

The incidence of plate exposure in the experimental group (17%) was significantly lower than that of the control group (43.1%; P < .0001). The mean time from reconstruction until plate exposure in the experimental group was 19.4 ± 23.6 months, whereas the mean time in the control group was 12.3 ± 9.1 months. In the logistic regression model for the occurrence of plate exposure, the only factor found to be associated with plate exposure was how the ALT flap was used (P = .026).

CONCLUSIONS

The results of the present study indicate that wrapping the reconstruction plate with an ALT flap decreased the incidence of plate exposure in patients with oromandibular defects.

Retrospective analysis of complications in 190 mandibular resections and simultaneous reconstructions with free fibula flap, iliac crest flap or reconstruction plate: a comparative single centre study

Objectives

The purpose of this study was to evaluate the incidence of complications following mandibular reconstruction and to analyse possible contributing factors.

Materials and methods

Clinical data and computed tomography scans of all patients who needed a mandibular reconstruction with a reconstruction plate, free fibula flap (FFF) or iliac crest (DCIA) flap between August 2010 and August 2015 were retrospectively analysed.

Results

One hundred and ninety patients were enrolled, encompassing 77 reconstructions with reconstruction plate, 89 reconstructions with FFF and 24 reconstructions with DCIA flaps. Cutaneous perforation was most frequently detected in the plate subgroup within the early interval and overall (each p = 0.004). Low body mass index (BMI) and total radiation dosage were the most relevant risk factors for the development of analysed complications.

Conclusions

Microvascular bone flaps have overall less skin perforation than reconstruction plates. BMI and expected total radiation dosage have to be respected in choice of reconstructive technique.

Clinical relevance

A treatment algorithm for mandibular reconstructions on the basis of our results is presented.

Electronic supplementary material

The online version of this article (10.1007/s00784-020-03607-8) contains supplementary material, which is available to authorized users.

Complications After Soft Tissue With Plate vs Bony Mandibular Reconstruction: A Systematic Review and Meta-analysis

OBJECTIVE

Mandibular reconstruction for segmental defects is a well-studied topic. However, there are conflicting data on the risks of delayed plate-related complications. The objective of this systematic review and meta-analysis was to assess long-term plate-related complications following reconstruction of the mandible with soft tissue and a plate as compared with immediate vascularized bony reconstruction.

DATA SOURCES

A medical librarian created search strategies with a combination of keywords and controlled vocabulary in Ovid Medline (1946-), Embase (1947-), Scopus (1960-), Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Clinicaltrials.gov.

REVIEW METHODS

Candidate articles were independently reviewed by 2 authors. Inclusion/exclusion criteria were uniformly applied. Articles were considered eligible if they included adequate reporting of plate extrusion and/or fracture and had follow-up ≥12 months.

RESULTS

A total of 2379 patients were included. The risk of plate fracture was low in cases of soft tissue with a plate (5%; 95% CI, 0.03-0.08) and osseous reconstruction (1%). The risk of extrusion following soft tissue and plate reconstruction was 20% (95% CI, 0.15-0.27). In the osseous reconstruction group, the risk of extrusion was 10% (95% CI, 0.06-0.18). Revision surgery was performed twice as often following soft tissue with a plate as compared with vascularized bony reconstruction (32% [95% CI, 0.25-0.40] vs 14% [95% CI, 0.09-0.21], respectively).

CONCLUSION

Delayed plate-related complications remain a significant problem following segmental defect reconstruction. Soft tissue and plate reconstruction techniques may increase the risk of plate removal and revision surgery.

Lateral segmental mandibulectomy reconstruction with bridging reconstruction plate and anterolateral thigh free flap: a case series of 30 consecutive patients

Lateral posterior segmental mandibular defects present a reconstructive challenge and an osseous flap would be the gold standard to reconstruct such a defect. However, combining a mandibular reconstruction plate (MRP) with a soft-tissue free flap (to restore mucosal integrity and provide durable coverage of the plate itself) offers an alternative option for posterior segmental mandibular defects in patients who are not suitable for osseous reconstruction, or do not choose it. We retrospectively reviewed 30 consecutive patients (19 male and 11 female) who underwent reconstruction of a segmental mandibulectomy defect using a bridging MRP and anterolateral thigh (ALT) free flap. The mean (range) age was 67 (31-87) years. The American Society of Anesthesiologists' (ASA) status of the study population comprised Grade 1 (n = 10), Grade 2 (n = 18), and Grade 3 (n = 2). The majority of patients had oral cavity squamous cell carcinoma (n = 26) involving the mandible, two had osteoradionecrosis, and two mucoepidermoid carcinoma. Four patients had complications specific to the reconstruction, and flap loss occurred in one (96.7% success rate). Metalwork infection occurred in three, including one plate extrusion and one plate fracture. The median length of stay was 10 days, and mean (range) duration of follow up 23.3 (1-96) months. This technique is an alternative reconstructive option for the non-tooth-bearing mandible. Reconstructing a posterolateral segmental mandibulectomy defect with a bridging MRP and ALT free flap offers a robust reconstructive alternative with a favourable complication profile.

Experimental Biointegration of a Titanium Implant in Delayed Mandibular Reconstruction

Background: Mandibular reconstruction, after extensive resection of the mandible for the treatment of oral cancer, is a well-known procedure, however, relatively little is known about bone integration into the titanium implant after reconstruction with a temporary plastic implant. The main goal of this experimental study was to study the process of osseous integration into the titanium implant in an in vivo experiment following prior mandibular reconstruction with a temporary plastic implant. Materials and Methods: Four ewes initially underwent a partial one-sided resection of the mandible, with the formation of an approximately 3 × 1 cm defect. All of the subjects received reconstruction with an implantation of a plastic plate (3 cm). The plastic plate was removed and replaced by a titanium implant at 1, 3, 6, and 12 months, accordingly. Both plastic and titanium implants were made via 3D-printing technology and personalized modeling. A total of 6 months after titanium implantation, a histological evaluation of biointegration was performed. Results: All surgeries were uncomplicated. The integration of osseous tissue into the titanium implant was seen in all cases. Histologically, each case showed variable integration of dense fibrotic tissue with fibroblasts and non-mature bone tissue with a definitive layer of bone matrix with many osteoblasts on the periphery. The prior implantation of the plastic plate did not interfere with bone integration into the titanium implant. Conclusion: Preliminary results demonstrated that a temporary plastic implant for mandibular reconstruction does not interfere with the consequent osseous biointegration of a permanent titanium implant. This shows that temporary reconstruction is a safe solution when delayed mandibular reconstruction is required due to disease severity.

A small number of residual teeth after the mandibular resection of oral cancer is associated with titanium reconstruction plate exposure

Objective

Reconstruction plates are used to treat patients with a segmental mandibular defect after oral cancer surgery. Reconstruction plate failure analysis has rarely focused on occlusion, which conducts a mechanical force to the mandible and the plate. To determine the prognostic factors, we retrospectively evaluated patients who underwent reconstruction of a mandibular segmental defect with a reconstruction plate and assessed the number of residual paired teeth.

Material and Methods

From among 390 patients with oral cancer who visited University of Tsukuba Hospital (Tsukuba, Japan) between 2007 and 2017, we selected and analyzed the data of 37 patients who underwent segmental resection of the mandible and reconstruction with reconstruction plates. Prognostic factors evaluated were patient age, sex, TNM classification, plate manufacturer, treatment with radiotherapy or chemotherapy, whether the patient had diabetes or smoked, and whether the patient had a small number of residual paired teeth, plate length, and use of a fibular‐free flap. Among these 37 patients, eight reconstruction plates had intraoral or extraoral exposure and were removed in 5 years.

Results

Kaplan–Meier and log‐rank analyses revealed that the prognosis for the 5‐year plate exposure‐free rate was significantly poorer for patients with a small number of residual teeth than for patients with no teeth or those with a large number of residual teeth (.01). Univariate Cox regression analysis revealed that a small number of residual teeth was a significant prognostic factor in the loss of a reconstruction plate (hazard ratio: 5.63; 95% confidence interval [1.10, 25.85]; .04).

Conclusions

A small number of residual teeth after the segmental resection of oral cancer is significantly involved in reconstruction plate survival and may be important in predicting reconstruction plate prognosis.

Partial mandibulectomy without bony reconstruction in patients with oropharyngeal or mouth cancer

Aim of the study

Resection of tumours of the oral cavity has significant consequences relating to function and aesthetic properties. Advancements in surgical techniques and microvascular surgery have enabled reconstructive outcomes to reach those of pre-surgery levels with good functional and aesthetic results. However, reconstructive options are not without complications.

Material and methods

We report the outcome of 23 patients with large tumours of the oral cavity or floor of the mouth, who underwent resection of the tumour and parts of the mandible without bony reconstruction. The patient population consisted of 19 oropharyngeal carcinomas and four floor of the mouth cancers, all of which had stage cT4 (six female and 17 male patients), and with an average patient age of 59.8 years. The pre- and postoperative ability to open the mouth, level of pain while masticating, mastication function pre and post-surgery, and the aesthetic outcome post-surgery were measured.

Results

The results obtained were deemed pleasantly acceptable by the patients, from aesthetic, functional, and analgesic points of view.

Discussion

A thorough preoperative work up is required and discussion with a multidisciplinary team is a necessity. This treatment option is more acceptable to the patient than would be expected and provides a satisfactory functional and aesthetic outcome. Therefore, we believe that partial mandibulectomy without bony reconstruction is an acceptable management option for a carefully selected group of patients who may not be suitable for the extensive surgery involved with bony reconstruction.

Composite Nanofibers Containing Multiwall Carbon Nanotubes as Biodegradable Membranes in Reconstructive Medicine

We have tested titanium (Ti) plates that are used for bone reconstruction in maxillofacial surgery, in combination with five types of novel long-resorbable biomaterials: (i) PCL₀-polycaprolactone without additives, (ii) PCLMWCNT-polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT), (iii) PCLOH-polycaprolactone doped with multiwall carbon nanotubes (MWCNT) containing ⁻OH hydroxyl groups, (iv) PCLCOOH-polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT) containing carboxyl groups, and (v) PCLTI-polycaprolactone with the addition of Ti nanoparticles. The structure and properties of the obtained materials have been examined with the use of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and/or X-ray powder diffraction (XRD). Titanium BR plates have been covered with: (i) PCL₀ fibers (PCL0BR-connection plates), (ii) PCLMWCNT fibers (PCLMWCNTBR-plates), (iii) PCLOH fibers (PCLOHBR-plates), (iv) PCLCOOH (PCLCOOHBR-plates), (v) PCLTI fiber (PCLTIBR-connection plates). Such modified titanium plates were exposed to X-ray doses corresponding to those applied in head and neck tumor treatment. The potential leaching of toxic materials upon the irradiation of such modified titanium plates, and their effect on normal human dermal fibroblasts (NHDF) have been assessed by MTT assay. The presented results show variable biological responses depending on the modifications to titanium plates.

Mandibular Condyle Reconstruction With Fibula Free-Tissue Transfer: The Role of the Masseter Muscle

BACKGROUND

Free fibula flap is an option for primary restoration after disarticulation mandibular resection, though literature on technique refinements is scarce. The authors hypothesized that inset of the masseter, the key mandibular elevator muscle, at the reconstructed mandible may optimize functional recovery.

METHODS

All patients undergoing reconstruction of mandibulectomy-condylectomy defect (January 2009 to January 2014) by means of a fibular flap were prospectively studied. The neocondyle was formed by the distal portion of the fibula and placed directly into the glenoid fossa with preservation of the temporomandibular disc. The deep portion of the masseter was inset at the angle of the reconstructed mandible.Condylar position was postoperatively evaluated by panoramic radiographs. Patients self-evaluated speech, chewing, swallowing, and facial appearance.

RESULTS

Two patients had immediate and 3 delayed reconstruction involving condyle ramus body, in the study period. During a mean follow-up of 32 months, 4 patients had satisfactory occlusion, 1 patient had an open-bite deformity, but was able to masticate solid food and maintain an oral diet. Although no significant condyle dislocation was recorded, 2 patients had slight ipsilateral deviation on mouth opening. Nevertheless, cosmesis was satisfactory and all patients maintained intelligible speech. Functional score was 13.6 ± 1.14 and facial appearance score was 4 ± 0.7.

CONCLUSION

The free fibula transfers with direct seating of the fibula into the condylar fossa followed by masseter muscle reinsertion provides acceptable functional reconstruction of the mandibulectomy-condylectomy defect.

Surgical site infections following oral cavity cancer resection and reconstruction is a risk factor for plate exposure

Background

Plate-related complications following head and neck cancer ablation and reconstruction remains a challenging problem often requiring further management and reconstructive surgeries. We aim to identify an association between surgical site infections (SSI) and plate exposure.

Methods

A retrospective study between 1997 and 2014 was performed to study the association between postoperative SSI and plate exposures. Eligible patients included those with a history of oral squamous cell carcinoma who underwent surgical resection, neck dissection, and free tissue reconstruction. Demographic and treatment related information was collected. SSI were classified based on CDC definition and previously published literature. Univariable analysis on demographic factors, smoking history, diabetes, radiation, surgical and hardware related factors; while multivariable analysis on SSI, plate height, segmental mandibulectomy defects and radiation were conducted such as using cox proportional hazard models.

Results

Three hundred sixty-five patients were identified and included in our study. The mean age of the study group was 59.2 (+/−13.8), with a predominance of male patients (61.9%). 10.7% of our patient cohort had diabetes, and another 63.8% had post-operative radiation therapy. Patients with SSI were more likely to have plate exposure (25 vs. 6.4%, p <0.001). Post-operative SSI, mandibulectomy defects, and plate profile/thickness were associated with plate exposure on univariable analysis (OR = 5.72, p < 0.001; OR = 2.56, p = 0.014; OR = 1.44, p = 0.003 respectively) and multivariable analysis (OR = 5.13, p < 0.001; OR = 1.36, p = 0.017; OR = 2.58, p = 0.02 respectively).

Conclusion

Surgical site infections are associated with higher rates of plate exposure. Plate exposure may require multiple procedures to manage and occasionally free flap reconstruction.

Finite Element Simulation and Additive Manufacturing of Stiffness-Matched NiTi Fixation Hardware for Mandibular Reconstruction Surgery

Process parameters and post-processing heat treatment techniques have been developed to produce both shape memory and superelastic NiTi using Additive Manufacturing. By introducing engineered porosity, the stiffness of NiTi can be tuned to the level closely matching cortical bone. Using additively manufactured porous superelastic NiTi, we have proposed the use of patient-specific, stiffness-matched fixation hardware, for mandible skeletal reconstructive surgery. Currently, Ti-6Al-4V is the most commonly used material for skeletal fixation devices. Although this material offers more than sufficient strength for immobilization during the bone healing process, the high stiffness of Ti-6Al-4V implants can cause stress shielding. In this paper, we present a study of mandibular reconstruction that uses a dry cadaver mandible to validate our geometric and biomechanical design and fabrication (i.e., 3D printing) of NiTi skeletal fixation hardware. Based on the reference-dried mandible, we have developed a Finite Element model to evaluate the performance of the proposed fixation. Our results show a closer-to-normal stress distribution and an enhanced contact pressure at the bone graft interface than would be in the case with Ti-6Al-4V off-the-shelf fixation hardware. The porous fixation plates used in this study were fabricated by selective laser melting.

Newly designed retentive posts of mandibular reconstruction plate in oral cancer patients based on preliminary FEM study

BACKGROUND

The reconstruction of a large mandibular defect poses a challenging issue in oral cancer ablation surgery. One popular option for mandibular continuity reconstruction after tumor resection involves the use of a reconstruction plate (R-plate), which maintains space and contour without bone harvesting. An R-plate, however, cannot provide final functional loading rehabilitation with implants or dentures.

METHODS

We suggest a new method of functional mandibular reconstruction using retentive posts and an upper prosthesis. The finite element method (FEM) was used to optimize the design. Surgery was needed to adapt the retentive posts. Prosthodontic procedures were required for the upper prosthesis.

RESULTS

Eight patients were treated with retentive posts and prostheses. All patients underwent wide resections of the mandible, and reconstruction with an R-plate and microvascular soft tissue transfer. We adapted the retentive posts on an R-plate and fabricated the upper prostheses with a flexible denture or a fixed resin prosthesis. Finally, the patients had functional rehabilitation, which restored proper mastication.

CONCLUSIONS

The retentive posts of the R-plate and upper prosthesis allow functional dental rehabilitation without the need for a bone graft. Virtual simulation using FEM will help to design and optimize the retentive posts. Two or three regular size posts are suitable for the quadrant jaw. This first preliminary step will allow improved patient-specific retentive post designs in the near future.

Diagnostic Features and Management Strategy of a Refractory Case of Osteoradionecrosis of the Mandible: Case Report and Review of Literature

INTRODUCTION

Osteoradionecrosis of the jaws produces a considerable amount of esthetic as well as functional deficits seriously affecting quality of life of the patient. Cases are often notoriously difficult to treat and manage owing to associated comorbidities of the patient, post irradiation fibrosis and decreased vascularity at the site, which complicates free tissue flap and graft transfer, that subsequently succumb to failure. Hyperbaric oxygen therapy (HBOT), in which 100 % oxygen is administered by mask under 2.4 atm pressure, in a hyperbaric oxygen chamber, helps by increasing local vascularity.

AIM AND METHODS

It was the aim of this study to show that a particularly refractory, compromised and challenging case of osteoradionecrosis can be managed successfully even without HBOT, by mandibular segmental resection followed by reconstruction using a titanium reconstruction plate enveloped within a pedicled Pectoralis Major Myocutaneous flap.

RESULT

Post operative recovery of the patient was excellent with good functional and esthetic rehabilitation of the patient with and practically nil donor site morbidity.

CONCLUSION

It is important to have a thorough knowledge of the clinical, radiographic, histopathologic, CT and MRI features of osteoradionecrosis of the jaws in order to make a quick and accurate confirmatory diagnosis and to overcome possible diagnostic dilemmas. The strategy of reconstruction of a large mandibular defect using a bridging titanium plate sandwiched by a healthy vascularized myocutaneous flap, following ablative surgery for ORN, has proved to be a safe and reliable option for composite mandibular defects, with gratifying long term functional and cosmetic results.

Influence of internal fixation systems on radiation therapy for spinal tumor

In this study, the influence of internal fixation systems on radiation therapy for spinal tumor was investigated in order to derive a theoretical basis for adjustment of radiation dose for patients with spinal tumor and internal fixation. Based on a common method of internal fixation after resection of spinal tumor, different models of spinal internal fixation were constructed using the lumbar vertebra of fresh domestic pigs and titanium alloy as the internal fixation system. Variations in radiation dose in the vertebral body and partial spinal cord in different types of internal fixation were studied under the same radiation condition (6 MV and 600 mGy) in different fixation models and compared with those irradiated based on the treatment planning system (TPS). Our results showed that spinal internal fixation materials have great impact on the radiation dose absorbed by spinal tumors. Under the same radiation condition, the influence of anterior internal fixation material or combined anterior and posterior approach on radiation dose at the anterior border of the vertebral body was the greatest. Regardless of the kinds of internal fixation method employed, radiation dose at the anterior border of the vertebral body was significantly different from that at other positions. Notably, the influence of posterior internal fixation material on the anterior wall of the vertebral canal was the greatest. X‐ray attenuation and scattering should be taken into consideration for most patients with bone metastasis that receive fixation of metal implants. Further evaluation should then be conducted with modified TPS in order to minimize the potentially harmful effects of inappropriate radiation dose.

PACS number: 87.55.D‐

Reconstruction plates used in the surgery for mandibular discontinuity defect

OBJECTIVES

The purpose of this study was to analyze the survival rate of reconstruction plates that were used to correct mandibular discontinuity defects.

MATERIALS AND METHODS

We analyzed clinical and radiological data of 36 patients. Only discontinuous mandibular defect cases were included in the study. Reconstruction plate survival rate was analyzed according to age, gender, location of defect, defect size, and whether the patient underwent a bone graft procedure, coronoidectomy, and/or postoperative radiation therapy (RT).

RESULTS

Plate-related complications developed in 8 patients, 7 of which underwent plate removal. No significant differences were found in plate survival rate according to age, gender, location of defect, defect size, or whether a bone graft procedure was performed. However, there were differences in the plate survival rate that depended on whether the patient underwent coronoidectomy or postoperative RT. In the early stages (9.25±5.10 months), plate fracture was the most common complication, but in the later stages (35.75±17.00 months), screw loosening was the most common complication.

CONCLUSION

It is important to establish the time-related risk of complications such as plate fracture or screw loosening. Coronoidectomy should be considered in most cases to prevent complications. Postoperative RT can affect the survival rate and hazard rate after a reconstruction plate is fitted.

Comparison of Mechanical Stability between Fibular Free Flap Reconstruction versus Locking Mandibular Reconstruction Plate Fixation

Background

The fibular free flap has been used as the standard methods of segmental mandibular reconstruction. The objective of mandibular reconstruction not only includes restored continuity of the mandible but also the recovery of optimal function. This paper emphasizes the advantage of the fibular free flap reconstruction over that of locking mandibular reconstruction plate fixation.

Methods

The hospital charts of all patients (n=20) who had a mandibular reconstruction between 1994 and 2013 were retrospectively reviewed. Eight patients had plate-only fixation of the mandible, and the remaining 12 had vascularized fibular free flap reconstruction. Complications and outcomes were reviewed and compared between the 2 groups via statistical analysis.

Results

Overall complication rates were significantly lower in the fibular flap group (8.3%) than in the plate fixation group (87.5%; p =0.001). Most (7/8) patients in the plate fixation group had experienced plate-related late complications, including plate fracture or exposure. In the fibular flap group, no complications were observed, except for a single case of donor-site wound dehiscence (1/12).

Conclusion

The fibular free flap provides a more stable support and additional soft tissue support for the plate, thereby minimizing the risk of plate-related complications. Fibular free flap is the most reliable option for mandibular reconstruction, and we believe that the flap should be performed primarily whenever possible.

Reconstructive Surgery for Head and Neck Cancer Patients

The field of head and neck surgery has gone through numerous changes in the past two decades. Microvascular free flap reconstructions largely replaced other techniques. More importantly, there has been a paradigm shift toward seeking not only to achieve reliable wound closure to protect vital structures, but also to reestablish normal function and appearance. The present paper will present an algorithmic approach to head and neck reconstruction of various subsites, using an evidence-based approach wherever possible.

Alloplastic mandibular reconstruction: a systematic review and meta-analysis of the current century case series

BACKGROUND

Alloplastic mandibular reconstruction remains insufficiently predictable, with no systematic reviews to assess its scope and limitations.

METHODS

The PubMed, CINAHL, EMBASE, and Web of Science databases were searched for English study reports, published in the current century, of mere alloplastic surgical reconstruction of mandibular ablative defects.

RESULTS

In 14 articles, there were 944 patients, with a median age of 58.7 years (interquartile range, 53.2 to 62 years); 58.7 percent (interquartile range, 66.7 to 78.6 percent) were male. Cases of squamous cell carcinoma per study constituted 93.5 percent (interquartile range, 81.5 to 100 percent). Defects were mostly lateral (Boyd classification) (60.5 percent; interquartile range, 56.2 to 62 percent) and received mostly conventional bridging plates (in 64.3 percent of the studies) and pedicled flaps (45.3 percent; interquartile range, 37.1 to 58.3 percent); 60.7 percent (interquartile range, 53.5 to 58.8 percent) received adjuvant therapy. At 32-month follow-up, the complication and failure rates were 40.1 percent (interquartile range, 26.7 to 58.6 percent) and 30.8 percent (interquartile range, 11.7 to 48.1 percent), respectively. The overall survival rate was 55 percent (interquartile range, 27.8 to 74 percent). Radiotherapy seemed to be a relative risk factor for complications (1.387; p = 0.014) and plate loss (1.585; p = 0.006). Crossing the midline seemed to be a relative risk factor for plate exposure (1.533; p = 0.000) and overall complications (1.385; p = 0.002).

CONCLUSIONS

The results should be generalized cautiously. Alloplastic reconstructive surgery faces a remarkable lack of evidence. Relatively high complication and failure rates are areas of further concern.

Carbon plate shows even distribution of stress, decreases screw loosening, and increases recovery of preoperative daily feed intake amount in a rabbit model of mandibular continuity defects

INTRODUCTION

The aim of this study was to compare a carbon plate (CP) and a titanium mandibular reconstruction plate (TMRP) in finite element analysis and an animal model.

MATERIALS AND METHODS

Twelve rabbits were used for this experiment. After a mandible continuity defect was created, either a CP or a TMRP was used for mandibular reconstruction. Postoperatively, daily feed intake amount (DFIA) was measured for 4 weeks. Radiographic images were also acquired to evaluate screw loosening. For the analysis of the stress distribution, a simple continuity defect model was used, and finite element analysis was performed.

RESULTS

The CP group had 0.80 ± 0.45 lost screws in an animal during the 4 weeks postoperative observation; however, the TMRP group had 1.86 ± 0.69 lost screws (p = 0.014). Overall, the 5 out of 5 of rabbits in the CP group and 3 out of 7 in the TMRP group exhibited preoperative levels of DFIA during the 4 week observation (p = 0.038). The finite element analysis showed that the stress was more evenly distributed in the CP than in the TMRP model.

CONCLUSIONS

The CP group showed decreased screw loosening and increased recovery of preoperative DFIA compared to the TMRP group in a rabbit model of mandibular continuity defects. Perfect adaptation of CP during the operation could not be achieved in spite of reshaping to the mandibular curvature. This disadvantage of the CP system can be overcome by the prefabricated technique using a prototype model.

The promotion of mandibular defect healing by the targeting of S1P receptors and the recruitment of alternatively activated macrophages

Endogenous signals originating at the site of injury are involved in the paracrine recruitment, proliferation, and differentiation of circulating progenitor and diverse inflammatory cell types. Here, we investigate a strategy to exploit endogenous cell recruitment mechanisms to regenerate injured bone by local targeting and activation of sphingosine-1-phosphate (S1P) receptors. A mandibular defect model was selected for evaluating regeneration of bone following trauma or congenital disease. The particular challenges of mandibular reconstruction are inherent in the complex anatomy and function of the bone given that the area is highly vascularized and in close proximity to muscle. Nanofibers composed of poly(DL-lactide-co-glycolide) (PLAGA) and polycaprolactone (PCL) were used to delivery FTY720, a targeted agonist of S1P receptors 1 and 3. In vitro culture of bone progenitor cells on drug-loaded constructs significantly enhanced SDF1α mediated chemotaxis of bone marrow mononuclear cells. In vivo results show that local delivery of FTY720 from composite nanofibers enhanced blood vessel ingrowth and increased recruitment of M2 alternatively activated macrophages, leading to significant osseous tissue ingrowth into critical sized defects after 12 weeks of treatment. These results demonstrate that local activation of S1P receptors is a regenerative cue resulting in recruitment of wound healing or anti-inflammatory macrophages and bone healing. Use of such small molecule therapy can provide an alternative to biological factors for the clinical treatment of critical size craniofacial defects.

Reconstruction of mandibular defects

Defects requiring reconstruction in the mandible are commonly encountered and may result from resection of benign or malignant lesions, trauma, or osteoradionecrosis. Mandibular defects can be classified according to location and extent, as well as involvement of mucosa, skin, and tongue. Vascularized bone flaps, in general, provide the best functional and aesthetic outcome, with the fibula flap remaining the gold standard for mandible reconstruction. In this review, we discuss classification and approach to reconstruction of mandibular defects. We also elaborate upon four commonly used free osteocutaneous flaps, inclusive of fibula, iliac crest, scapula, and radial forearm. Finally, we discuss indications and use of osseointegrated implants as well as recent advances in mandibular reconstruction.