Local and systemic risk factors influencing the long-term success of angular stable alloplastic reconstruction plates of the mandible

Penetration of the Scalp by the Bent Fragment of a Pre-installed Titanium Mini-Plate Due to a Minor Head Injury: A Case Report

Titanium mini-plates are commonly used for bone flap fixation in craniotomy and are particularly essential for covering burr holes. Plate exposure through the scalp may occur because of scalp thinning caused by infection or local ischemia, and penetration of the scalp by a titanium mini-plate that had been bent by a minor head injury are rare. A 69-year-old man who had undergone covering of a burr hole in the calvarium by a titanium plate for clipping of a ruptured aneurysm 17 years ago was referred to our clinic to examine metal protruding through the scalp. One year previously, he had hit his head on a wall with no consequence until one week ago, when he noted the protruding metal. Plain skull radiography showed that a portion of the pinwheel-shaped titanium mini-plate had been bent upward and was exposed through the scalp. As the wound was contaminated with sebum, the plate and three screws securing it were removed through a linear skin incision under local anesthesia. The wound healed uneventfully, and the sutures were removed 10 days later. Bone flap fixation requires careful attention. When a five-screw hole pinwheel-shaped titanium mini-plate is used to cover a burr hole, all five holes should be fixed to the skull/bone flap to prevent bending in the future. Alternatively, a wing that is not fixed with a screw should be cut or a rectangular or diamond-shaped plate should be used.

The Perfect Timing-Immediate versus Delayed Microvascular Reconstruction of the Mandible

In this retrospective study, the clinical and economic implications of microvascular reconstruction of the mandible were assessed, comparing immediate versus delayed surgical approaches. Utilizing data from two German university departments for oral and maxillofacial surgery, the study included patients who underwent mandibular reconstruction following continuity resection. The data assessed included demographic information, reconstruction details, medical history, dental rehabilitation status, and flap survival rates. In total, 177 cases (131 male and 46 females; mean age: 59 years) of bony free flap reconstruction (72 immediate and 105 delayed) were included. Most patients received adjuvant treatment (81% with radiotherapy and 51% combined radiochemotherapy), primarily for tumor resection. Flap survival was not significantly influenced by the timing of reconstruction, radiotherapy status, or the mean interval (14.5 months) between resection and reconstruction. However, immediate reconstruction had consumed significantly fewer resources. The rate of implant-supported masticatory rehabilitation was only 18% overall. This study suggests that immediate jaw reconstruction is economically advantageous without impacting flap survival rates. It emphasizes patient welfare as paramount over financial aspects in clinical decisions. Furthermore, this study highlights the need for improved pathways for masticatory rehabilitation, as evidenced by only 18% of patients with implant-supported dentures, to enhance quality of life and social integration.

Enhancing osseointegration of titanium implants through MC3T3-E1 protein-gelatin polyelectrolyte multilayers

Titanium and its alloys have found extensive use in the biomedical field, however, implant loosening due to weak osseointegration remains a concern. Improved surface morphology and chemical composition can enhance the osseointegration of the implant. Bioactive molecules have been utilized to modify the surface of the titanium-based material to achieve rapid and efficient osseointegration between the implant and bone tissues. In this study, the bioactive substance MC3T3-E1 protein-gelatin polyelectrolyte multilayers were constructed on the surface of the titanium implants by means of layer-by-layer self-assembly to enhance the strength of the bond between the bone tissue and the implant. The findings of the study indicate that the layer-by-layer self-assembly technique can enhance surface roughness and hydrophilicity to a considerable extent. Compared to pure titanium, the hydrophilicity of TiOH LBL was significantly increased with a water contact angle of 75.0 ± $$ \pm $$ 2.4°. The modified titanium implant exhibits superior biocompatibility and wound healing ability upon co-culture with cells. MC3T3-E1 cells were co-cultured with TiOH LBL for 1, 3, and 5 days and their viability was higher than 85%. In addition, the wound healing results demonstrate that TiOH LBL exhibited the highest migratory ability (243 ± 10 μm). Furthermore, after 7 days of osteogenic induction, the modified titanium implant significantly promotes osteoblast differentiation.

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.

Patient-specific 3D-printed mini-versus reconstruction plates for free flap fixation at the mandible: Retrospective study of clinical outcomes and complication rates

This study aimed to compare the clinical outcomes and complication rates of patient-specific 3D-printed mini- and reconstruction plates for free flap fixation in mandibular reconstruction. A retrospective monocentric study was carried out between April 2017 and December 2021 to analyze patients undergoing immediate mandibular reconstruction using fibula free flaps and osteosynthesis using patient-specific 3D-printed implants. Eighty-three patients with a mean age of 63.6 years were included. The mean follow-up period was 18.5 months. Patient-specific 3D-printed plates were designed as reconstruction plates (38 patients), miniplates (21 patients) or a combination of reconstruction- and miniplates (24 patients). With miniplates, plate removal was performed significantly more often via an intraoral approach (p < 0.001) and in an outpatient setting (p = 0.002). Univariate analysis showed a higher fistula rate with reconstruction plates (p = 0.037). Multivariate analysis showed no significant differences in complications. Case-control matching demonstrated significantly lower rates of fistula (p = 0.017) and non-union (p = 0.029) in the combined group. This retrospective study shows a tendency towards reduced complication rates with patient-specific 3D-printed miniplates in comparison to patient-specific 3D-printed reconstruction plates for immediate mandibular reconstruction with fibula free flaps.

Alloplastic reconstruction of the mandible after subtotal mandibulectomy for medication-related osteonecrosis of the jaw: An update of the method

BACKGROUND

Reconstruction of continuity defects following osteonecrosis in multimorbid patients is challenging. In all cases of the predescribed palliative treatment method for alloplastic mandible reconstruction, plate fractures were detected in follow-up. We hypothesized that a modification could avoid these fractures, leading to stable long-term results.

METHODS

This retrospective study compares the original method with a modification using single, laser-sintered CAD-CAM plates instead of manually bent miniplates. The predescribed shuttering technique was used to reconstruct the mandible in its original shape with bone cement.

RESULTS

Uneventful wound healing was observed in 86% of the cases after modification of the method. No implant or plate fracture occurred.

CONCLUSIONS

The presented method should be considered as a treatment option for mandible reconstruction in elderly, multimorbid patients in palliative situations. The results of this study suggest that the modification of the method leads to significantly improved long-term stability. Donor site morbidity is avoided with this method of palliative surgery.

Interdental Bone Level around Immediately Placed Implants at Maxillary and Mandibular Molar Sites: A Retrospective Radiographic Analysis

Background and Objectives: The current study aimed to compare the amount of interdental bone loss between early and immediate implant placements. Materials and Methods: A total of 16 immediate implants and 16 early implants radiographs were included in the current research. The bone level was assessed at two different stages: at the extraction appointment (T1) and after three to six months of implant placement (T2). A line was drawn from the cemento-enamel junction connecting adjacent teeth to the interdental line connecting the interdental alveolar crest at both stages. The difference between measurements in the T1 and T2 stages is the bone loss measurement for the early implant group. For the immediate implant placement sites, the measurements were taken from the interdental bone crest to the implant platform level. Results: A Mann-Whitney U test was performed to evaluate the differences between both groups. The descriptive statistics of the T1 and T2 stages for both groups suggest that the bone loss in the T2 stage was generally higher than T1 stage. The immediate implant group showed higher bone loss compared to the early implant group. Moreover, there was significantly higher bone loss (p = 0.039) in the immediate implant group compared to the early implant group. Conclusions: The results of this study indicate that immediate implant might have disadvantages over early implant in terms of bone loss after the extraction of maxillary and mandibular molar teeth.

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.

MRONJ of the Mandible—From Decortication to a Complex Jaw Reconstruction Using a CAD/CAM-Guided Bilateral Scapula Flap

Medication-related osteonecrosis of the jaw (MRONJ) has been an integral part of the maxillofacial patient population for some time. The therapeutic concept ranges from conservative approaches over less extended decortications to major jaw resections, which can result in a considerable loss of quality of life. Based on three case reports, this paper presents the long-term history of patients with MRONJ of the mandible, whose disease ultimately resulted in partial or total mandibular resection and subsequent multisegmental reconstruction using a microvascular anastomosed bone flap. Furthermore, a suitable alternative for complex mandibular reconstruction is demonstrated when using a free fibula flap is not possible. The options are limited, particularly when multisegmental restoration of mandibular continuity is required. One case presents a mandible reconstruction using a CAD/CAM-guided bilateral scapular free flap (CAD/CAM = Computer-Aided Design and Manufacturing), which has not been described for this purpose before. Due to the complexity, computer-assisted surgery and patient-specific implants seem reasonable, which is why a special focus was applied to this topic.

Titanium Internal Fixator Removal in Maxillofacial Surgery: Is It Necessary? A Systematic Review and Meta-Analysis

Titanium plates and screws are essential devices in maxillofacial surgery since late 1980s, but despite their wide use there is no consensus in titanium internal fixators removal after bone healing. A systematic literature review and meta-analysis were conducted on seventeen retrospective studies. Effect size and 95% confidence intervals were calculated for plate removal (per plate and per patient) and for removal causes (infection, pain, screws complications, exposition, palpability). Odds ratio, 95% confidence intervals, and χ 2 test were measured for sex, smoking, and implant site. Heterogeneity was evaluated with Cochran and Inconstancy test. Obtained data were used to design Forest and Funnel plots. The aim of the study is to identify and clarify reasons and risk factors for plates and screws removal. Infection is the most frequent reason; the habit of tobacco usage and implant site (mandibula) are the main risk factors. The administration of antibiotic prophylaxis is essential, and patients must quit smoking before and after surgery. In conclusion there is no scientific evidence supporting the removal of internal devices as mandatory step of the postoperative procedure.

Biomechanical analysis of mandibular defect reconstruction based on a new base-fixation system

Buccal titanium plate fixation is a common method for repairing mandibular defects. However, the method presents certain problems: the requirement of a large volume of titanium plate, a large number of fixation screws, a lengthy duration of the surgical operation, and exposure of the fixation plate which easily causes wound infection. In this study, a new base-fixation system was designed. Mandibular reconstruction was performed using the three-dimensional reconstruction package Mimics. In order to compare the newly designed base-fixation system and the common buccal-fixation system, the stress distributions and the displacement distributions of the whole model under two loading conditions were studied, based on the finite element analysis package ANSYS. The safety of the base-fixation titanium plate was evaluated. The results showed that although the maximum stress of the base-fixation titanium plate was higher than that of the buccal-fixation titanium plate, it was still less than the yield strength of titanium. Therefore, under the condition of applying 300 N of vertical occlusal loading, the base-fixation titanium plate displayed superior fixation ability without permanent deformation (and concomitant fixation failure). The results of the fatigue simulation analysis showed that the safety factor of the base-fixation titanium plate in the working state was 3.8 (>1.0), indicating that its fatigue performance met the application requirements. Compared with traditional buccal fixation, the novel base-fixation system has obvious advantages, suggesting its suitability as a new treatment method for clinical mandibular defect reconstruction.

CAD/CAM scaffolds for bone tissue engineering: investigation of biocompatibility of selective laser melted lightweight titanium

The objective of the current in-vitro study was to evaluate the biocompatibility of a new type of CAD/CAM scaffold for bone tissue engineering by using human cells. Porous lightweight titanium scaffolds and Bio-Oss® scaffolds as well as their eluates were used for incubation with human osteoblasts, fibroblasts and osteosarcoma cells. The cell viability was assessed by using fluorescein diazo-acetate propidium iodide staining. Cell proliferation and metabolism was examined by using MTT-, WST-Test and BrdU-ELISA tests. Scanning electron microscope was used for investigation of the cell adhesion behaviour. The number of devitalised cells in all treatment groups did not significantly deviate from the control group. According to MTT and WST results, the number of metabolically active cells was decreased by the eluates of both test groups with a more pronounced impact of the eluate from Bio-Oss®. The proliferation of the cells was inhibited by the addition of the eluates. Both scaffolds showed a partial surface coverage after 1 week and an extensive to complete coverage after 3 weeks. The CAD/CAM titanium scaffolds showed favourable biocompatibility compared to Bio-Oss® scaffolds in vitro. The opportunity of a defect-specific design and rapid prototyping by selective laser melting are relevant advantages in the field of bone tissue engineering and regenerative medicine.

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.

Pre-contoured reconstruction plate fabricated via three-dimensional printed bending support

A mandibular continuity defect can be repaired using either a prosthetic device or autogenous bone. A titanium reconstruction plate can be used with a localized or vascularized flap over the defect of the mandible. Unfortunately, the plate may fail due to plate exposure, screw loosening, fracture, or infection, and will need to be removed. Plate exposure though the skin or mucosa is one of the main reasons for failure. In the present work, the authors introduced a lingually positioned reconstruction plate fabricated via three-dimensional printed bending support. This custom reconstruction plate can avoid plate re-exposure as well as reduce surgical errors and operation time.

Biomaterials and osteoradionecrosis of the jaw: Review of the literature according to the SWiM methodology

OBJECTIVES

To systematically present and interpret the current literature on research and treatment perspectives for mandibular osteoradionecrosis (mORN) in the field of biomaterials.

MATERIAL AND METHODS

A systematic review of the literature using the "Synthesis without meta-analysis" (SWiM) methodology was performed on PubMed, Embase and Cochrane, focusing on the implantation of synthetic biomaterials for bone reconstruction in mORN in humans and/or animal models. The primary endpoints were the composition, efficacy on mORN and tolerance of the implanted synthetic biomaterials.

RESULTS

Forty-seven references were obtained and evaluated in full-text by two assessors. Ten (8 in humans and 2 in animal models) met the eligibility criteria and were included for analysis. Materials most often comprised support plates or metal mesh (5 of 10 cases) in combination with grafts or synthetic materials (phosphocalcic ceramics, glutaraldehyde). Other ceramic/polymer composites were also implanted. In half of the selected reports, active compounds (molecules, growth factors, lysates) and/or cells were associated with the reconstruction material. The number of articles referring to implantation of biomaterials for the treatment of mORN was small, and the properties of the implanted biomaterials were generally poorly described, thus limiting a thorough understanding of their role.

CONCLUSION

In preventing the morbidity associated with some reconstructive surgeries, basic research has benefitted from recent advances in tissue engineering and biomaterials to repair limited bone loss.

A Comprehensive Analysis of Complications of Free Flaps for Oromandibular Reconstruction

OBJECTIVES/HYPOTHESIS

To determine the frequency and management of short- and long-term complications related to oromandibular free flap reconstruction and identify potentially predictive factors of hardware complications.

STUDY DESIGN

Retrospective chart review.

METHODS

A retrospective database from chart review was formed consisting of 266 oromandibular free flap reconstructions performed at a single institution over a 15-year period. Data were collected on demographics, surgical treatment, complications, and management of complications. Subgroup univariate and multivariate analyses were performed to compare patients with hardware complications and those without.

RESULTS

Eighty-one of 266 patients (30.5%) that underwent oromandibular reconstruction had an early complication (<4 weeks after surgery), and the most common complications were cervical wound dehiscence (11.3%) and fistulas (9.40%). Eighty of 266 patients (30.1%) had a long-term complication (>4 weeks after surgery) and the most common complication was plate exposure (26.7%). Univariate and multivariate analyses showed no association between whether there was hardware extrusion and fibula versus scapula, smoking history, virtual surgical planning (VSP), and dental implantation (P > .05). Only early complications (OR, 3.59, 95% CI, 1.83-7.05, P < .01) and patients undergoing oromandibular reconstruction for osteoradionecrosis (OR, 2.26, 95% CI, 1.10-4.64, P = .03) were strongly and independently associated with subsequent hardware extrusion on univariate analysis.

CONCLUSIONS

Both short- and long-term complications are common after oromandibular reconstruction. The most important predictive factor for a late complication is an early complication and prior radiation. There was no difference of plate complications among the various free flap types. Dental implantation and use of VSP were not associated with hardware complications.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:1997-2005, 2021.

Evaluation of a novel osteosynthesis plate system for mandibular defects

Continuity defects of the jaw can be reconstructed with titanium plates or microvascular bone flaps; osteosynthesis plates are necessary for both. In this study we performed a retrospective review of patients treated with Medartis MODUS® Mandible Trauma/Reco 2.0-2.5, TriLock bridging plates, mandibulectomy and soft tissue free flap or reconstruction with a bony free flap and TriLock mandibular plates from the same system from January 2015 to August 2019. The variables recorded were sex, age, diagnosis, radiotherapy, date of implantation, date of explantation or death of patient, size of mandibular defect, Jewer classification of defect, number of screws used, segments of bony reconstruction, screws per segment, plate exposure, plate breakage, and pseudarthrosis. The bridging plate group consisted of 41 patients, while the mandibular plate group consisted of 24 patients. The percentage of plate exposure was 17.07% for the bridging plate group and 4.17% for the mandibular plate group. Plate breakage was 0 in both groups. Pseudarthrosis was 4.17% in the mandibular plate group. In the bridging plate group, an anterolateral thigh flap covered all exposures. Of 7 plate exposures, 4 were found in a C defect. The complication rate of the investigated plates was lower than the complication rates of other plate systems.

Lingual Application of Pre-Bent Reconstruction Plate for Segmental Mandibular Defect: Easy and Accurate Method Through the Buccal Drilling Approach Using Computer-Aided Design/Computer-Aided Manufacturing Surgical Guides

To prevent or treat for complications of reconstruction plate, such as metal plate fracture, plate exposure, and formation of skin fistula, the use of reconstruction plates on the mandibular lingual aspect has been introduced. However, this method increases the difficulty of surgery and lengthens the surgery time. In this study, the authors aimed to present a method to apply for reconstruction plates on the lingual side of the mandible to overcome the complications associated with the use of these plates. In the proposed method, the reconstruction plate was bent and fixed by a specially designed screws on a three-dimensional model created through a pre-operative virtual surgical simulation. Next, the model, prebent reconstruction plant, and screw were 3-dimensionally scanned and then superimposed precisely onto the three-dimensional model generated through the virtual surgical simulation. After extracting the three-dimensional path of the screws on the superimposed model, a surgical guide was prepared to drill screw holes in the buccal side of the mandible by transferring the extracted paths. The proposed surgical method using virtual surgical planning and surgical guides makes mandibular lingual application of the prebent reconstruction plates convenient, fast, and precise through drilling in the buccal side of the mandible.

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.

Establishment of a Numerical Model to Design an Electro-Stimulating System for a Porcine Mandibular Critical Size Defect

Electrical stimulation is a promising therapeutic approach for the regeneration of large bone defects. Innovative electrically stimulating implants for critical size defects in the lower jaw are under development and need to be optimized in silico and tested in vivo prior to application. In this context, numerical modelling and simulation are useful tools in the design process. In this study, a numerical model of an electrically stimulated minipig mandible was established to find optimal stimulation parameters that allow for a maximum area of beneficially stimulated tissue. Finite-element simulations were performed to determine the stimulation impact of the proposed implant design and to optimize the electric field distribution resulting from sinusoidal low-frequency ( f = 20 Hz ) electric stimulation. Optimal stimulation parameters of the electrode length h el = 25 m m and the stimulation potential φ stim = 0.5 V were determined. These parameter sets shall be applied in future in vivo validation studies. Furthermore, our results suggest that changing tissue properties during the course of the healing process might make a feedback-controlled stimulation system necessary.

Reconstruction plate-related complications in mandibular continuity defects

PURPOSE

The purpose of this study was to evaluate the complications associated with the use of reconstruction plates with or without non-vascularized bone graft in reconstruction of mandibular segmental defects caused by trauma and tumor resection and to analyze various factors that are associated with the development of complications.

METHODS

A retrospective observational study was conducted, and the investigated variables included the age and gender of the patients, etiology of the defect, the site of the defect, the size of the defect, whether bone graft was used or not, type of plate used, and whether the reconstruction was immediate or delayed. The outcome variables were the postoperative complications and the success rate.

RESULTS

Fifty-one patients were enrolled in this study; the etiology of mandibular defect was trauma in 39 patients (76.5%) and resection of benign or malignant tumors in 12 patients (23.5%). The complication rate was (58.8%) and the success rate was (94.1%); the only factor that significantly increased the incidence of postoperative complications was the size of the defect.

CONCLUSION

Reconstruction plates demonstrated a high success rate despite the high complication rate. Segmental defects caused by trauma were smaller than those created after tumor resection and the only factor that increased complication rate was the size of the defect; other factors did not affect the complication rate.

The fitting accuracy of pre-bend reconstruction plates and their impact on the temporomandibular joint

BACKGROUND

Various causes for bone defects of the lower jaw have been described. As a result, patients often suffer from compromised aesthetics and a loss of, or reduction in, important physiological functions, such as swallowing, breathing, and speaking. A change in the shape of the lower jaw can impair the natural occlusion and leads to an atypical or modified position of the temporomandibular joint. Titanium reconstruction plates are the standard approach to jaw reconstruction, and are used for temporary bridging of a jaw defect or fixation of a bone graft. Conventionally these plates are intraoperatively adjusted to the mandible by the surgeon. Computer-aided manufacturing, computer-aided design, and rapid prototyping have gained increasing importance in the field of medicine, as they allow the production of individual models of the lower jaw, with the possibility of preoperatively bending the reconstruction plates. In this retrospective study, the accuracy of pre-bent titanium plates and their effect on the temporomandibular joint situation in comparison with intraoperatively curved plates will be discussed.

MATERIALS AND METHODS

Patients who attended our department for lower jaw reconstruction between March 2013 and February 2015 were included in this retrospective study. Within that time 20 patients were treated with pre-bent reconstruction plates (group 1). 20 comparable patients were selected with reconstruction and conventional intraoperative bending (group 2). To evaluate the accuracy of the plates and the condylar position, postoperative cone beam computed tomograms and computed tomograms were used to assess the bone-plate distance at 12 defined points and four angles in axial reconstruction. The results were compared, statistically evaluated, and discussed.

RESULTS

Regarding the maximum bone-plate distances and the sum of distances, there was a significant difference between the accuracy of the pre-bent and the conventionally bent reconstruction plates (p = 0.022, p = 0.048). Regarding the condylar position, there was no significant difference between both methods (p = 0.867).

CONCLUSION

The results of this study show that a better fitting accuracy can be achieved using pre-bent plates. Preparation of the plates proves to be advantageous and meaningful, especially in complex bone defects and deformations of the lower jaw. Nevertheless, concerning the position of the temporomandibular joint, no significant difference could be ascertained between the shown methods, contradicting several studies.

Osseous response on linear and cyclic RGD-peptides immobilized on titanium surfaces in vitro and in vivo

Biomimetic surface modifications of titanium (Ti) implants using the Arg-Gly-Asp-sequence (RGD) are promising to accelerate bone healing in cases of medical implants. Therefore, we compared the impact of linear and cyclic RGD (l- and c-RGD) covalently coupled onto Ti surfaces on the osseous response in vitro and in vivo. In vitro, osteoblasts' behavior on different surfaces (unmodified, amino-silanized [APTES], l- and c-RGD) was analysed regarding adhesion (fluorescence microscopy), proliferation (resazurin stain) and differentiation (reverse transcription polymerase chain reaction on alkaline phosphatase and osteocalcin). In vivo, osteosynthesis screws (unmodified n = 8, l-RGD n = 8, c-RGD n = 8) were inserted into the proximal tibiae of 12 rabbits and evaluated for bone growth parameters (bone implant contact [%] and vertical bone apposition [VBA;%]) at 3 and 6 weeks. In vitro, c- as well as l-RGD surfaces stimulated osteoblasts' adherence, proliferation and differentiation in a similar manner, with only subtle evidence of superiority of the c-RGD modifications. In vivo, c-RGD-modifications led to a significantly increased VBA after 3 and 6 weeks. Thus, coating with c-RGD appears to play an important role influencing osteoblasts' behaviour in vitro but especially in vivo. These findings can be applied prospectively to implantable biomaterials with hypothetically improved survival and success rates. © 2017 Wiley Periodicals Inc. J Biomed Mater Res Part A: 106A: 419-427, 2018.

Predictive factors for premature loss of Martin 2.7 mandibular reconstruction plates

Mandibular reconstruction with a plate, with or without a vascularised free (bone) flap, is commonly used to treat patients with a segmental mandibular defect. Common complications are loosening of the osteosynthesis screws, malposition, intraoral or extraoral exposure, or infection. To define prognostic factors for premature loss of such plates and improve future planning, we designed a retrospective study of all patients operated on between 2005 and 2011 for reconstruction of a mandibular segmental defect with a reconstruction plate with or without a free vascularised (bone) flap. Prognostic factors collected from medical records were the patient's age, sex, and American Society of Anesthesiologists (ASA) grade; treatment with radiotherapy; whether they had diabetes or smoked; the site of the mandibular defect; whether there was a dental occlusion; the number of screws used on each side, and the use of a free vascularised (bone) flap; and whether the diagnosis was of oral cancer, benign tumour, or trauma. One hundred patients were included, 79 with oral cancer, 19 with benign tumours, and 2 with trauma. In 20 patients the Martin 2.7 reconstruction plate failed. Diabetes and smoking were significant prognostic factors for premature loss of the reconstruction plate with a hazard ratio of 2.95 (95% CI 1.068-8.172), p value=0.04, for diabetes, and 2.42 (95% CI 1.006-5.824), p value=0.05, for smoking. Smokers and diabetic patients have a higher risk of failure after mandibular reconstruction with a 2.7 reconstruction plate.

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.

A chemiluminescent light system in combination with toluidine blue to assess suspicious oral lesions-clinical evaluation and review of the literature

OBJECTIVES

The aim of the study was an evaluation of an acetic acid wash and chemiluminescent light system in combination with toluidine blue in order to detect visual identified, potentially malignant lesions.

MATERIALS AND METHODS

Forty-four patients with 50 oral lesions of primary uncertain visible dignity were included. Next to a clinical examination, a screening with ViziLite® (VL) as well as toluidine blue (TB; together ViziLite® Plus (VLP)) was conducted. Histopathology served as gold standard and sensitivity (SE), specificity (SP), positive as well as negative predictive value (PPV, NPV) was calculated descriptively. Additionally, a PubMed literature search using the key words "ViziLite" and "chemiluminescence oral cancer" was conducted.

RESULTS

Histological diagnosis showed 40 lesions of reactive/inflammatory nature, moderate dysplasia (n = 3) and oral squamous cell carcinoma (OSCC n = 7). All OSCCs and one dysplasia were identified correct via clinical diagnosis (SE 90 %, SP 100 %, PPV 100 %, NPV 97.5 %). VL examination could show all malignancies with low specificity (SE 100 %, SP 30 %, PPV 26 %, NPV 100 %). TB and VLP were positive in all cases of cancer and in one case of inflammation (SE 80 %, SP 97.5 %, PPV 89 %, NPV 95 %). In the review, eight clinical trials with similar results were included.

CONCLUSIONS

The adjunct of TB to VL reduces the number of false positives without increasing the rate of false negatives.

CLINICAL RELEVANCE

Clinical evidence to justify the additional cost of the system for diagnosis of suspicious lesions is weak. However, for the potential role of VLP in detection of lesions not otherwise identified in the visual exam in general dental practice further studies are required.