Reconstruction Of Segmental Defects Research Articles

Finite element analysis and clinical application of 3D-printed Ti alloy implant for the reconstruction of mandibular defects

BackgroundThe reconstruction of segmental defect of the mandible has always been a challenge. The customized reconstruction plate without a bone graft is also considered a transitional means of rehabilitation and reconstruction in some cases.MethodsThis study evaluated the biomechanical behaviors of customized plates with different structural designs comparing with commercial plates using the finite element method in reconstrution of the lateral mandible defect.ResultsSimulations revealed the stress state in the plate bodies, bone tissues and screws were associated with the width, height, thickness of the plates as well as the distribution of screws. In all of the groups, the system of 16 mm-high, 2.8 mm-thick customized reconstruction plate with 10 screws was considered to be the most ideal design because of the most harmonious biomechanical state. What’s more, the stress shielding effects were not obvious in this experiment. Based on the above findings, we conducted a clinical case analysis to verify the mechanical properties of customized reconstruction and obtained a satisfactory operation result.ConclusionsThe results show that by adjusting the contour parameters of the reconstruction plates, an ideal and reliable customized plate can be manufactured. And the customized 3D-printed Ti alloy implant will be a new way to achieve mandibular reconstruction in patients unable to perform autologous bone graft surgery.Trial registrationThe present trial has been registered with ChiCTR, the registration number is ChiCTR 2,000,038,973 on 11/10/2020.

Nonvascularized bone grafts: how successful are they in reconstruction of segmental mandibular defects?

ObjectiveSegmental mandibular defects can occur due to various etiologies, including trauma and tumor resection. Reconstruction should provide adequate support for subsequent dental rehabilitation and allow for proper occlusion. Non-vascularized bone grafts have been used for reconstructing mandibular defects in cases where vascularized grafts were not feasible. The objective of this study was to assess the success rate of these grafts in reconstruction of segmental defects of various sizes in the mandible. Study DesignFifty patients were included in this retrospective chart review. Length of the grafts varied from 3 to 20 cm and patients were followed-up from 4 to 80 months. Fifteen grafts were harvested from anterior iliac crest, 23 from posterior iliac crest, 9 grafts were a combination of either with costochondral graft, and 3 were solely allografts. Bone morphogenetic protein was utilized in 41 cases as an adjunct. ResultsSuccess was defined as continuity of bone clinically and radiographically at a 4-month follow-up. Non-vascularized bone grafting was successful in %90 of cases. Complications were observed in %34 of cases, of which the most common were infection followed by wound dehiscence. ConclusionOur study demonstrated substantial success rate with non-vascularized bone grafts in reconstruction of segmental mandibular defects.

Influence of surface engineering on 3D printed Ti lattice structure towards enhanced tissue integration: An in vitro and in vivo study

Reconstruction of segmental defects are popularly approached with surface engineered additively manufactured scaffolds owing to its enhanced post-surgery tissue integration properties. The present work is aimed at fabrication of Ti lattice structures using 3D printing, with a novel approach of silane chemistry-based surface modification of those Ti-surfaces with osteogenic peptides (OGP). The lattice structures with 0.6 mm strut-diameter having 0.5 mm inter-strut distance were chosen for fabrication using an extrusion-based 3D printing. Based on the evidence, it could be concluded that extrusion-based 3D printing is an optimal alternative as compared to those high cost incurring additive manufacturing processes. Therefore, OGP were grafted on the pristine Ti-surfaces using a silane chemistry based novel vapour deposition process. In vitro assessments of the surface modified scaffolds using human amniotic derived mesenchymal stem cells showed evidence of enhanced cell adhesion and viability. In vivo subcutaneous study in rat models of the surface modified Ti-scaffolds also showed enhanced tissue integration in terms of Collagen I deposition around the boundary of the tissue-integrated struts as compared to those of pristine scaffolds. The study has established that the novel surface modification technique is capable to engineer the Ti-surfaces towards enhanced tissue integration in vivo.

A tissue engineered 3D printed calcium alkali phosphate bioceramic bone graft enables vascularization and regeneration of critical-size discontinuity bony defects in vivo.

Introduction: Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering. The current study explored an advanced bone tissue engineering approach combining an advanced 3D printing technique for bioactive resorbable ceramic scaffolds with a perfusion cell culture technique for pre-colonization with mesenchymal stem cells, and with an intrinsic angiogenesis technique for regenerating critical size, segmental discontinuity defects in vivo applying a rat model. To this end, the effect of differing Si-CAOP (silica containing calcium alkali orthophosphate) scaffold microarchitecture arising from 3D powder bed printing (RP) or the Schwarzwalder Somers (SSM) replica fabrication technique on vascularization and bone regeneration was analyzed in vivo. In 80 rats 6-mm segmental discontinuity defects were created in the left femur. Methods: Embryonic mesenchymal stem cells were cultured on RP and SSM scaffolds for 7d under perfusion to create Si-CAOP grafts with terminally differentiated osteoblasts and mineralizing bone matrix. These scaffolds were implanted into the segmental defects in combination with an arteriovenous bundle (AVB). Native scaffolds without cells or AVB served as controls. After 3 and 6months, femurs were processed for angio-µCT or hard tissue histology, histomorphometric and immunohistochemical analysis of angiogenic and osteogenic marker expression. Results: At 3 and 6months, defects reconstructed with RP scaffolds, cells and AVB displayed a statistically significant higher bone area fraction, blood vessel volume%, blood vessel surface/volume, blood vessel thickness, density and linear density than defects treated with the other scaffold configurations. Discussion: Taken together, this study demonstrated that the AVB technique is well suited for inducing adequate vascularization of the tissue engineered scaffold graft in segmental defects after 3 and 6months, and that our tissue engineering approach employing 3D powder bed printed scaffolds facilitated segmental defect repair.

Functional outcomes following mandibulectomy and fibular free-flap reconstruction

There remains a paucity of evidence with regards to functional outcomes following the reconstruction of segmental defects in the mandible. It is, however, well recognised that oral rehabilitation following head and neck surgery is a driver of improved quality of life outcomes. We present a prospective service review of functional outcomes of a consecutive cohort of patients following segmental mandibulectomy and virtual surgical planning (VSP) composite fibular free-flap reconstruction. Twenty-five patients, who were identified as having a complete dataset with a minimum of 12 months’ follow up, ultimately met the inclusion criteria. Validated functional outcome measures were used primarily to assess speech, diet, and swallowing outcomes. The results demonstrate a decline in both speech and swallowing outcomes at three months postoperatively, with a decline of 37% in the Speech Handicap Index from the preoperative baseline, and a decline of 35% in the MD Anderson Dysphagia Inventory score over the same period. The MD Anderson Dysphagia Inventory score improved at 12 months, whereas the Speech Handicap Index did not. Fundamentally a collaborative approach is required between members of the multidisciplinary team (MDT) to enable optimal patient outcomes.

Ossification of Non-vascularized Free-Fibula Graft for Mandibular Reconstruction after Resection of Ameloblastoma: Review of Literature and Presentation of 2 cases

Introduction: Ameloblastoma is a benign neoplasm of odontogenic epithelial origin occurring more commonly in the mandibular posterior region and rarely in the maxilla. About 50-60% of ameloblastomas occur in the mandibular ramus area, while only 10% is seen in mandibular anterior region. Ameloblastomas are slow growing, locally invasive, rarely malignant tumours affecting the jaw. Mostly commonly seen in the 4th-6th decade of life affecting males more commonly than females. The resection of the mandibular segment without adequate reconstruction leads to functional as well as esthetic loss. Case Report: Here we describe two case reports of ameloblastoma with segmental resection and reconstruction using fibula graft. Discussion & Review of Literature: Avascular fibula graft with its high bone density, ease of access to harvest, and tendency to show less resorption helps to achieve satisfactory esthetic contour and function in reconstruction of segmental defects of mandible Conclusion: This article describes two case reports of ameloblastoma with segmental resection and reconstruction using fibula graft along with review of literature.

Segmental Mandibular Reconstruction Using Tissue Engineering Strategies: A Systematic Review of Individual Patient Data.

The aim of the systematic review was to analyze the current clinical evidence concerning the use of tissue engineering as a treatment strategy for reconstruction of segmental defects of the mandible and their clinical outcomes using individual patient data. A systematic review of the literature was conducted using PubMed and Cochrane Library on May 21, 2019. The eligibility criteria included patients in whom segmental mandibular reconstruction was carried out using tissue engineering as the primary treatment strategy. After screening and checking for eligibility, individual patient data were extracted to the extent it was available. Data extraction included the type of tissue engineering strategy, demographics, and indication for treatment, and outcomes included clinical and radiographic outcome measures, vitality of engineered bone, dental rehabilitation, and patient-reported outcome measures and complications. Out of a total of 408 articles identified, 44 articles reporting on 285 patients were included, of which 179 patients fulfilled the inclusion criteria. The different tissue engineering treatment strategies could be broadly classified into 5 groups: "prefabrication," "cell culture," "bone morphogenetic protein (BMP) without autografts," "BMP with autografts," and "scaffolds containing autografts." Most included studies were case reports or case series. A wide variety of components were used as scaffolds, cells, and biological substances. There was not a single outcome measure that was both objective and consistently reported, although most studies reported successful outcome. A wide variety of tissue engineering strategies were used for segmental mandibular reconstruction that could be classified into 5 groups. Due to the low number of treated patients, lack of standardized and consistent reporting outcomes, lack of comparative studies, and low evidence of reported literature, there is insufficient evidence to recommend any particular tissue engineering strategy.

Large enchondroma of metacarpal bone without pathological fracture treated with marginal resection and reconstruction with iliac crest graft: A case report

Enchondroma is the benign bone tumor commonly found in phalanx and metacarpal shaft. The most common method of treatment is curettage with or without filling the cavity with bone graft with recurrence rate up to 13%. We chose to present this case of a large enchondroma of fourth metacarpal right hand treated with marginal excision and reconstruction of segmental defect with tricortical iliac crest bone graft with excellent functional and cosmetic result. The reason to report this case was owing to the large size of the tumor without pathological fracture despite of long duration and successful reconstruction of metacarpal with simple technique of autograft.

Comparison of Ilizarov Bifocal, Acute Shortening and Relengthening with Bone Transport in the Treatment of Infected, Segmental Defects of the Tibia.

This prospective study compared bifocal acute shortening and relengthening (ASR) with bone transport (BT) in a consecutive series of complex tibial infected non-unions and osteomyelitis, for the reconstruction of segmental defects created at the surgical resection of the infection. Patients with an infected tibial segmental defect (>2 cm) were eligible for inclusion. Patients were allocated to ASR or BT, using a standardized protocol, depending on defect size, the condition of soft tissues and the state of the fibula (intact or divided). We recorded the Weber–Cech classification, previous operations, external fixation time, external fixation index (EFI), follow-up duration, time to union, ASAMI bone and functional scores and complications. A total of 47 patients (ASR: 20 patients, BT: 27 patients) with a median follow-up of 37.9 months (range 16–128) were included. In the ASR group, the mean bone defect size measured 4.0 cm, and the mean frame time was 8.8 months. In the BT group, the mean bone defect size measured 5.9cm, and the mean frame time was 10.3 months. There was no statistically significant difference in the EFI between ASR and BT (2.0 and 1.8 months/cm, respectively) (p = 0.223). A total of 3/20 patients of the ASR and 15/27 of the BT group needed further unplanned surgery during Ilizarov treatment (p = 0.006). Docking site surgery was significantly more frequent in BT; 66.7%, versus ASL; 5.0% (p < 0.0001). The infection eradication rate was 100% in both groups at final follow-up. Final ASAMI functional rating scores and bone scores were similar in both groups. Segmental resection with the Ilizarov method is effective and safe for reconstruction of infected tibial defects, allowing the eradication of infection and high union rates. However, BT demonstrated a higher rate of unplanned surgeries, especially docking site revisions. Acute shortening and relengthening does not reduce the fixator index. Both techniques deliver good functional outcome after completion of treatment.

Low skeletal muscle mass is a strong predictive factor for surgical complications and a prognostic factor in oral cancer patients undergoing mandibular reconstruction with a free fibula flap.

Fibula free flaps (FFF) are effective in accomplishing successful reconstruction for segmental defects of the mandible. Potential risk factors for FFF complications have been described in previous research, e.g. age, comorbidity and smoking. Low skeletal muscle mass (SMM) has shown to be an emerging predictive factor for complications and prognostic factor for survival in head and neck cancer. This study aims to identify the predictive and prognostic value of low SMM for surgical FFF related complications, postoperative complications and survival in patients who underwent mandibular reconstruction with FFF after oral cavity cancer resection. A retrospective study was performed between 2002 and 2018. Pre-treatment SMM was measured at the level of the third cervical vertebra and converted to SMM at the level of the third lumbar vertebra (L3). SMM at the level of L3 was corrected for squared height. Low SMM was defined as a lumbar skeletal muscle index (LSMI) below 43.2cm2/m2. 78 patients were included, of which 48 (61.5%) had low SMM. Low SMM was associated with an increased risk of FFF related complications (HR 4.3; p=0.02) and severe postoperative complications (Clavien-Dindo grade III-IV) (HR 4.0; p=0.02). In addition low SMM was a prognosticator for overall survival (HR 2.4; p=0.02) independent of age at time of operation, ACE-27 score and TNM stage. Low SMM is a strong predictive factor for FFF reconstruction complications and other postoperative complications in patients undergoing FFF reconstruction of the mandible. Low SMM is also prognostic for decreased overall survival.

The vascularized medial femoral condyle free flap for reconstruction of segmental recalcitrant nonunion of the clavicle

Recalcitrant clavicular nonunion is a rare but complicated problem of clavicular fracture fixation. Nonunion is most often treated with clavicular shortening or in extreme cases vascularized bone grafting. Herein we describe our experience using the vascularized medial femoral condyle (MFC) free flap for the reconstruction of segmental defects in cases of recalcitrant clavicular nonunion. A retrospective chart review was conducted of patients with symptomatic recalcitrant nonunion of the clavicle who underwent reconstruction with the vascularized MFC free flap from June 2003 to January 2018. Patients' demographics, time to union, and postoperative complications were collected. A total of 7 patients(6 women; 39.8 ± 9.01 years old) underwent clavicular reconstruction after an average of 3.7 ± 1.3 previous surgical procedures. Average preoperative visual analogscale score for pain was 4.1. The graft size ranged from 2 to 5 cm in length with approximately 1 cm in width and depth. The average time of total nonunion was 66 ± 48.2 months before surgery. All flaps survived and all clavicles healed with an average time to radiographic union of 15 ± 6.7 months. Patients regained full shoulder motion, and average postoperative visual analog scale score was 1.6 ± 1.8. All patients returned to their preoperative employment status. Donor site morbidity from the knee was minimal. The MFC free flap is a good option for recalcitrant bone nonunion of the clavicle where larger vascularized flaps are not warranted. It is effective and offers minimal donor site morbidity.

Nerve Conduit Enhancement with Vomeronasal Organ Improves Rat Sciatic Functional Index in a Segmental Nerve Defect Model

Segmental nerve loss presents a challenge to the reconstructive surgeon. Collagen nerve conduits are one strategy for reconstruction of segmental defects, but no conduit-based reconstructive strategy has been as successful as autograft reconstruction. We hypothesized that collagen nerve conduits used to bridge segmental sciatic nerve defects may be enhanced by grafting with vomeronasal organ (VNO), owing to this tissue’s capacity for regeneration. Fourteen rats underwent resection of a 1.0 cm segment of sciatic nerve. Seven rats underwent reconstruction of the defect using a commercially available collagen nerve conduit. Seven rats underwent reconstruction using conduit filled with fresh VNO allograft. An additional seven rats underwent transection and direct epineural repair. Fourteen weeks postoperatively, all animals underwent calculation of sciatic functional index (SFI) via walking track analysis. After sacrifice, tissues were processed for histomorphometric analysis, including axon quantification and axon density. All reconstructed nerves were in continuity at sacrifice. At 14 weeks, the mean SFI was significantly higher in the vomeronasal organ-enhanced (VNOE) group and epineural repair (ER) group than the conduit-only (CO) group. `SFI was equivalent between VNOE and ER groups. Axon density was greater in the VNOE and ER groups than the CO group. Axon density was equivalent between VNOE and ER groups. In conclusion, this rat sciatic nerve segmental defect model achieved greater functional recovery and axon density using collagen nerve conduits filled with a pluripotent neuroepithelium relative to reconstruction with an empty conduit. These results suggest a promising strategy for repair of segmental peripheral nerve defects.

Large Enchondroma of Metacarpal Bone with Pathological Fracture Treated with Marginal Resection and Reconstruction with Iliac Crest Graft: A Rare Case Report

Enchondroma is the benign bone tumor commonly found in phalanx and metacarpal shaft. The most common method of treatment is curettage with or without filling cavity with bone graft with recurrence rate up to 13%. We present a large enchondroma of fourth metacarpal right hand with cortical breach treated with marginal excision and reconstruction of segmental defect with tricortical iliac crest bone graft with excellent functional and cosmetic result. We opted to report this case because of the large size of the tumor and successful reconstruction of metacarpal with simple technique of autograft.

Auto-Allo Graft Parallel Juxtaposition for Improved Neuroregeneration in Peripheral Nerve Reconstruction Based on Acellular Nerve Allografts.

Nerve repair poses a significant surgical challenge, and much research on this topic for improvement in reconstruction of segmental defects is ongoing. The aims of the study were to reconfirm the accuracy and safety of a previously described nerve decellularization method on a larger experimental population of rabbits, as well as on human nerves, and to establish in vivo the efficacy of a new-concept mixed graft, comprising autologous and acellular nerve allograft components within the same graft. Acellular nerve allografts were implanted into tibial nerve defects of 5 rabbits (group A), autografts were implanted, representing the criterion standard, in other 5 animals (group B), and the innovative technique was used in the remaining 5 (group C). Twelve weeks postoperatively, nerve conduction evaluations were performed; animals were euthanatized, and grafts were harvested and morphologically, histomorphometrically, and immunohistochemically analyzed. Eventually, a preliminary in vitro validation of the decellularization method was performed on human nerves from a cadaver. No clinical adverse effect was revealed during all the experimental times. No tissue reaction was observed, and in all groups, regenerated fascicles and bundles were shown by histology. However, both histology and histomorphometry demonstrated a better regenerative efficiency in group C. The morphological evaluation of the human nerve treated with the novel method showed complete decellularization. The microsurgical combined model demonstrated a better neuroregeneration than did pure autografts and acellular nerve allografts. The decellularization method seemed effective also on human nerves. Deeper investigations are necessary to further validate and transfer this new encouraging protocol to the clinical arena.

Acute open callus manipulation: Clinical experience with a new surgical technique for solving old problems in distraction osteogenesis

BackgroundTransport distraction osteogenesis is challenged as a potential alternative to free-flap reconstruction of segmental jaw defects due to its longer treatment time, vector control difficulties, need for additional bone-grafting, and problems creating a curvilinear shape. We propose a new technique of acute open callus manipulation and fixation (AOCMF), which addresses these challenges. MethodsA retrospective analysis of all patients with jaw defects who underwent DO and AOCMF between 2006 and 2015 was performed. Clinical and demographic data were recorded and analysed. Representative treated cases were presented. ResultsFourteen adult patients were treated, seven for maxillary and seven for mandibular defects of mixed etiology. The mean length of distraction was 4.9 cm (range 3–8 cm). AOCMF was performed between the first and third week of the consolidation phase. Average treatment time was 7.6 weeks (range 4–13 weeks). Mean follow-up was 38 months (range 25–76 months). Stable curvilinear bone shape and soft tissue coverage was achieved in all patients except one. Four complications were recorded. ConclusionsAOCMF following DO is a safe and reliable technique for reconstruction of segmental defects. It represents a useful alternative to free-flap reconstruction in selected patients. When compared with traditional bone transport techniques, it allows a decrease in the number of surgical procedures and in average treatment time.

A Modification of an Established Method of Intercalary Extremity Bone Defect Reconstruction: The "Hemi-Capanna" Technique.

Skeletal reconstruction of segmental defects of the appendicular skeleton is among the most challenging tasks in reconstructive surgery. A popular method of reconstruction of large osseous defects is the combination of massive allografts and vascularized bone transfer. We present and discuss our experience with a modification of the traditional Capanna technique in which the allograft is split in half longitudinally to provide for more space for postoperative fibula hypertrophy. Patients who underwent reconstruction of segmental intercalary defects of the tibia using our modified technique were retrospectively identified. The following parameters were retrieved: patient age, race, sex, length of skeletal defect, recipient vessels, type of microsurgical anastomosis, union rate, complication rate, ambulation (yes/no), and follow-up (in months). Two male patients underwent reconstruction of the tibia via the modified "hemi-Capanna" technique. The tibia defect measured 12 and 13 cm, respectively. No intraoperative or postoperative complications were encountered. Osseous union was obtained in both patients who are both ambulatory. The hemi-Capanna technique not only leaves more room for hypertrophy of the vascularized fibula, but also simplifies the technique of combining an allograft with vascularized bone transfer in reconstructions of segmental skeletal defects of the appendicular skeleton.

Biomechanical Analysis of a Novel Intercalary Prosthesis for Humeral Diaphyseal Segmental Defect Reconstruction.

To study the biomechanical properties of a novel modular intercalary prosthesis for humeral diaphyseal segmental defect reconstruction, to establish valid finite element humerus and prosthesis models, and to analyze the biomechanical differences in modular intercalary prostheses with or without plate fixation. Three groups were set up to compare the performance of the prosthesis: intact humerus, humerus-prosthesis and humerus-prosthesis-plate. The models of the three groups were transferred to finite element software. Boundary conditions, material properties, and mesh generation were set up for both the prosthesis and the humerus. In addition, 100 N or 2 N.m torsion was loaded to the elbow joint surface with the glenohumeral joint surface fixed. Humeral finite element models were established according to CT scans of the cadaveric bone; reverse engineering software Geomagic was used in this procedure. Components of prosthetic models were established using 3-D modeling software Solidworks. To verify the finite element models, the in vitro tests were simulated using a mechanical testing machine (Bionix; MTS Systems Corporation, USA). Starting with a 50 N preload, the specimen was subjected to 5 times tensile (300 N) and torsional (5 N.m) strength; interval time was 30 min to allow full recovery for the next specimen load. Axial tensile and torsional loads were applied to the elbow joint surface to simulate lifting heavy objects or twisting something, with the glenohumeral joint surface fixed. Stress distribution on the humerus did not change its tendency notably after reconstruction by intercalary prosthesis whether with or without a plate. The special design which included a plate and prosthesis effectively diminished stress on the stem where aseptic loosening often takes place. Stress distribution major concentrate upon two stems without plate addition, maximum stress on proximal and distal stem respectively diminish 27.37% and 13.23% under tension, 10.66% and 11.16% under torsion after plate allied. The novel intercalary prosthesis has excellent ability to reconstruct humeral diaphyseal defects. The accessory fixation system, which included a plate and prosthesis, improved the rigidity of anti-tension and anti-torsion, and diminished the risk of prosthetic loosening and dislocation. A finite element analysis is a kind of convenient and practicable method to be used as the confirmation of experimental biomechanics study.

Reconstruction of Mandibular Segmental Detects Using Transport Disk Distraction Osteogenesis.

Distraction osteogenesis (DO) has become an important alternative for bone defect reconstruction. The study aims to investigate the clinical feasibility and efficiency of transport disc DO (TDDO) for reconstruction of segmental defect of mandible and further dental implant treatment. A serial of 6 patients diagnosed with ameloblastoma or keratocystic odontogenic tumor were included in this study. Computed tomography (CT) scanning and panoramic radiograph were performed for preoperative evaluation and surgery planning. Transport disc DO was applied simultaneously with tumor resection for reconstruction of mandibular defects. The postoperative panoramic radiographs and CT scans were taken for evaluation of the ossification level. Then a second surgery was performed for removal of the distraction apparatus. Bone graft and rigid internal fixation were also used to fill the gap between the transport disc and the stump of the residual ramus. Further dental implant treatment was also finished or in progress. All patients finished the whole treatment period, and no distraction device failure or tumor recurrence occurred. The distraction length ranged from 35 to 48 mm and the whole treatment period of TDDO ranged from 21 to 33 weeks. High degree of ossification was confirmed at the end of treatment by postoperative radiographs and intraoperative observation. Infection occurred in 1 of the 6 patients, and the symptom was controlled by surgical dressing change and flushing. Results of final facial profile in all patients were good. Three patients finished dental implant treatment with good occlusion. Results in this study suggest the clinical feasibility and efficiency of TDDO for reconstruction of segmental defect of mandible and further dental implant treatment.

Finite-element design and optimization of a three-dimensional tetrahedral porous titanium scaffold for the reconstruction of mandibular defects

Reconstruction of segmental defects in the mandible remains a challenge for maxillofacial surgery. The use of porous scaffolds is a potential method for repairing these defects. Now, additive manufacturing techniques provide a solution for the fabrication of porous scaffolds with specific geometrical shapes and complex structures. The goal of this study was to design and optimize a three-dimensional tetrahedral titanium scaffold for the reconstruction of mandibular defects. With a fixed strut diameter of 0.45mm and a mean cell size of 2.2mm, a tetrahedral structural porous scaffold was designed for a simulated anatomical defect derived from computed tomography (CT) data of a human mandible. An optimization method based on the concept of uniform stress was performed on the initial scaffold to realize a minimal-weight design. Geometric and mechanical comparisons between the initial and optimized scaffold show that the optimized scaffold exhibits a larger porosity, 81.90%, as well as a more homogeneous stress distribution. These results demonstrate that tetrahedral structural titanium scaffolds are feasible structures for repairing mandibular defects, and that the proposed optimization scheme has the ability to produce superior scaffolds for mandibular reconstruction with better stability, higher porosity, and less weight.

Arthroscopic Reconstruction of Segmental Defects of the Hip Labrum: Results in 22 Patients With Mean 2-Year Follow-Up

To report mean 2-year patient-reported outcomes (PROs) and the incidence of revision hip arthroscopy or conversion to total hip arthroplasty (THA) in patients who had undergone arthroscopic reconstruction of the hip labrum for segmental defects. Data were prospectively collected and retrospectively reviewed on all patients who had undergone hip arthroscopy from April 2008 to April 2013. All patients who underwent arthroscopic labral reconstruction with either a semitendinosus allograft or a gracilis autograft with mean 2-year follow-up were part of the inclusion criteria. The following outcomes were recorded: modified Harris hip score, nonarthritic athletic hip score, hip outcome score-sports-specific subscale, hip outcome score-activities of daily living subscale, visual analog scale, for pain, patient satisfaction, revision hip arthroscopies, and conversion to THA. A 2-tailed Student's t-test was used to assess for statistically significant differences between the mean of preoperative and postoperative PROs. P values less than .05 were considered statistically significant. A total of 22 patients (14 females, 8 males) met the inclusion criteria. There was 100% follow-up. The mean age of the study population was 32.2years. Twelve patients had reconstruction as part of a revision procedure and 10 patients had a reconstruction at the time of primary arthroscopy. Concomitant arthroscopic procedures included acetabuloplasty and femoroplasty. There was statistically significant improvement in all PROs (P= .013 to <.001). The mean changes for the modified Harris hip score, nonarthritic athletic hip score, hip outcome score-sports-specific subscale, and hip outcome score-activities of daily living subscale were 11.0 ± 19.5, 22.2 ± 15.0, 23.1 ± 30.9, and 19.1 ± 17.5 points, respectively. The mean improvement in the visual analog scale was 3.33 ± 2.92 points (P < .001), and the mean patient satisfaction was 6.73 out of 10 points. One patient required conversion to THA for presumed progression of osteoarthritis and 2 patients required a revision procedure for adhesions. This arthroscopic technique for labral reconstruction was associated with a significant improvement in PROs and function. Conversion to THA with the procedure was 4.5%. Level IV, therapeutic case series.