Recent advances in reconstructive oral and maxillofacial surgery

Robotic and Plastic Surgery: actuality and prospects for the near future, a scoping review

OBJECTIVE

This work aims to review the existing use of robotics in plastic surgery.

METHODS

A meticulous selection process identified 22 articles relevant to this scoping review.

RESULTS

The literature on the use of robotics in plastic surgery is sparse. Nonetheless, this review highlights emerging benefits in microsurgery, breast reconstruction, and transoral surgery.

CONCLUSION

This scoping review identifies critical articles reporting the emerging use of robotics in plastic surgery. While the scientific medical community has yet to extensively document its use, the available evidence suggests a promising future for robotics in this field.

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

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

The Utility of 3D Printing for Surgical Planning and Patient-Specific Implant Design in Maxillofacial Surgery: A Narrative Review

Maxillofacial reconstructive implants are typically created in standard shapes and have a widespread application in head and neck surgery. During surgical procedures, the implant must be correctly bent according to the architecture of the particular bones. Bending takes practice, especially for untrained surgeons. Furthermore, repeated bending may increase internal stress, resulting in fatigue in vivo under masticatory loading and an array of consequences, including implant failure. There is a risk of fracture, screw loosening, and bone resorption. Resorption, infection, and displacement are usually associated with the use of premade alloplastic implants and autogenous grafts. Recent technological breakthroughs have led to the use of patient-specific implants (PSIs) developed by computer-designed additive manufacturing in reconstructive surgery. The use of computer-designed three-dimensional (3D)-printed PSI allows for more precise restoration of maxillofacial deformities, avoiding the common difficulties associated with premade implants and increasing patient satisfaction. Additive manufacturing is something that refers to a group of additive manufacturing methods. This technique has been quickly used in a variety of surgical procedures. The exponential expansion of this technology can be attributed to its enormous surgical value. Adding 3D printing to a medical practice can be a rewarding experience with stunning results.

Secondary healing property using Neoveil®, a polyglycolic acid bioabsorbable sheet on the oral mucosal defects

Neoveil® is a wound surface-covering agent composed of polyglycolic acid(PGA) effective for secondary healing. This study evaluated the secondary healing property of oral cavity mucosal defects using the PGA sheet. Thirty-four patients who underwent surgical excision of oral benign and malignant lesions, precancerous lesions, and tumors were evaluated. The PGA sheet was placed over the open wound to aid secondary healing. The defects were reviewed post-operatively for secondary healing, contracture, and secondary deformity. Male to female ratio was 20:14, and the mean age was 63.5 years. In all cases, the oral mucosal defect was present after the wide excision of the mucosal lesion. The PGA sheet was used as a surface covering agent which was found to be effective in secondary healing of the wound. Any side effects and adverse reactions which were caused by the PGA sheet was not evident. It can be used to avoid skin graft or free flap reconstruction or deformity from the direct closure in moderate size oral mucosal defect.

Primary Reconstruction in Segmental Resection of Mandible-An Outcome Analysis of Different Reconstructive Techniques

Functional and cosmetic defects in the maxillofacial region may result from trauma, inflammatory disease, benign or malignant tumors. There are several well established reconstructive options for restoring mandibular continuity and function. Traditionally, surgeons have used their past experience to determine the best way to perform the osteotomy, graft harvesting, and graft shaping procedures for mandibular reconstruction. Focus has now shifted to optimize functional and aesthetic outcomes in mandible reconstruction. Refinements in surgical techniques continue to improve patient's quality of life. The purpose of this study was to evaluate the outcome of a range of reconstructive techniques in 20 patients who underwent segmental resection of mandible during the period 2004-2017.

Evaluation of the Proximal Tibia as a Donor Site of Cancellous Bone for Intraoral Grafting Procedures-A Retrospective Study

Background: Autogenous bone grafts remain the “gold standard” in maxillofacial reconstructive procedures. The objective of this study was to evaluate the proximal tibia as a donor site of cancellous bone for bone grafting procedures of the mandible on the basis of intraoperative parameters and clinical observations. Methods: The study was based on a medical record search of 40 patients who underwent surgical procedures because of benign pathological lesions of the jaws resulting in 3-wall bone defects of the mandible and qualified for surgical removal of the lesion with simultaneous bone grafting of the defect with autogenous cancellous bone harvested from the proximal tibia. Results: The use of the proximal tibia for bone grafting procedures enables large amounts of cancellous bone (15.09 cc in average) to be obtained. The procedure is characterized by a low risk of early and late complications, which include excessive bleeding, wound infection, lengthy healing time, scars, a loss of sensation around the scars, aching, a dip in bone, swelling and tenderness. Conclusions: The ability to obtain large amounts of cancellous bone and a low risk of intra- and postoperative complications make the proximal tibia an attractive donor site for the bone grafting procedures in maxillofacial surgery.

The development of computer-aided patient-specific template design software for 3D printing in cranio-maxillofacial surgery

BACKGROUND

The patient-specific templates for osteotomy often have complex surface features. Using current commercial software to design such templates is quite complicated, tedious and unrepeatable.

AIMS

In this study, a novel surgical planning system for oral and maxillofacial surgery named EasyTemplate is developed, aiming to help doctors shorten the modelling time and assure the reliability in template design.

MATERIALS & METHODS

In the simplified design process of an osteotomy guide, the main template can be formed efficiently using a surface offsetting algorithm, which is based on isosurface extraction and oriented bounding box. Thereafter, the cutting grooves can be generated automatically.

RESULTS

A complicated surgical guide could be built accurately in about 10 min. Clinical orthognathic cases were conducted successfully using osteotomy and repositioning templates designed by EasyTemplate.

DISCUSSION

Compared with commercially available softwares, higher efficiency and simpler design process were achieved, moreover, the time cost is one-third or even less.

CONCLUSION

EasyTemplate can be a useful alternative to traditional softwares. This software allows the auto-generation algorithm which helps avoid a tedious modeling process while providing basic shapes for designers.

A Preliminary Study on Animal Experiments of Robot-Assisted Craniotomy

BACKGROUND

Traditional craniotomy relies on the surgeon's experience and can be complicated owing to excessive skull bone removal, undesirable brain tissue penetration, or severe bleeding. For craniotomy, we developed a robot system based on intraoperative cone-beam computed tomography image guidance and human-robot cooperative interaction, aiming to improve the safety and accuracy of surgery and reduce the labor-intensiveness of the procedure.

METHODS

Intraoperative cone-beam computed tomography image guidance was adopt to improve the accuracy in our experiment. Craniotomy was performed using an interactive method based on human-robot collaboration, which could achieve a natural interactive method in accordance with surgeons' operating habits. The frequency-based method of contact distinction and the method of torque estimation were used to improve the safety of the designed robot.

RESULTS

An animal experiment was conducted to verify the effectiveness of the robot system. During the drilling process, the position error was 0.92 ± 0.17 mm (upper surface) and 0.97 ± 0.11 mm (lower surface), and the angle error was 3.37 ± 1.43°. During the milling process, the position error was 1.06 ± 0.13 mm (upper surface) and 1.09 ± 0.09 mm (lower surface). The results showed that the system had sufficient precision and could better complete craniotomy with human-robot collaboration. In addition, with the feedback of multisensor information, the robot system could achieve a sufficient level of safety.

CONCLUSIONS

The robot system can achieve accurate positioning and safe user-friendly human-robot interaction, which solves problems encountered in the drilling and milling of craniotomy, meets clinical needs, and provides a new method for robot-assisted craniotomy.

Feasibility of the application of mixed reality in mandible reconstruction with fibula flap: A cadaveric specimen study

BACKGROUND

In recent years, a new technology, mixed reality (MR), has emerged and surpassed the limitations of augmented reality (AR) with its inability to interact with hologram. This study aimed to investigate the feasibility of the application of MR in mandible reconstruction with fibula flap.

METHODS

Computed tomography (CT) examination was performed for one cadaveric mandible and ten fibula bones. Using professional software Proplan CMF 3.0 (Materialize, Leuven, Belgium), we created a defected mandibular model and simulated the reconstruction design with these 10 fibula bones. The surgical plans were transferred to the HoloLens. We used HoloLens to guide the osteotomy and shaping of the fibular bone. After fixing the fibular segments using the Ti template, all segments underwent a CT examination. Before and after objects were compared for measurements of the location of fibular osteotomies, angular deviation of fibular segments, and intergonial angle distances.

RESULTS

The mean location of the fibular osteotomies, angular deviation of the fibular segments, and intergonial angle distances were 2.11 ± 1.31 mm, 2.85°± 1.97°, and 7.24 ± 3.42 mm, respectively.

CONCLUSION

The experimental results revealed that slight deviations remained in the accuracy of fibular osteotomy. With the further development of technology, it has the potential to improve the efficiency and precision of the reconstructive surgery.

Development and Characterization of a Rabbit Model of Compromised Maxillofacial Wound Healing

IMPACT STATEMENT

Maxillofacial defects often present the clinical challenge of a compromised wound bed. Preclinical evaluation of tissue engineering techniques developed to facilitate healing and reconstruction typically involves animal models with ideal wound beds. The healthy wound bed scenario does not fully mimic the complex clinical environment in patients, which can lead to technology failure when translating from preclinical in vivo research to clinical use. The reported preclinical animal model of compromised wound healing enables investigation of tissue engineering technologies in a more clinically relevant scenario, potentially fostering translation of promising results in preclinical research to patients.

Virtual Surgical Planning for Successful Second-Stage Mandibular Defect Reconstruction Using Vascularized Iliac Crest Bone Flap: A Valid and Reliable Method

PURPOSE

Second-stage reconstruction of mandibular defects faces problems of anatomic disorder and bone displacement due to tumor resection. As a newer technique, virtual surgical planning (VSP) may help to increase the accuracy and efficiency of the complicated reconstruction. This study aims to evaluate the application of VSP and splint-guided surgery in second-stage mandibular reconstruction using vascularized iliac crest bone flap.

METHODS

Between October 2016 and February 2018, 5 patients (3 men and 2 women) with mandibular defects of duration between 8 months and 8 years underwent VSP-aided secondary reconstruction in the School and Hospital of Stomatology of Wuhan University (Wuhan, China). Virtual surgical planning was performed and serial guiding splints were printed to replicate the design into the actual operation. The linear and 3-dimensional deviations after surgery were analyzed. Patient complications and feedback were recorded during follow up.

RESULTS

All 5 patients underwent successful reconstruction using vascularized iliac crest bone flap. No serious donor sites or recipient site complications were observed after 10- to 28-month follow-up. In comparison with the presurgery designs, the linear deviations in coronal plane were 2.7 ± 0.4 mm (range, -2.2 to 3.9 mm) in measurements from the condylar head to the condylar head and 0.70 ± 0.6 mm (range, -0.1 to 1.7 mm) from the gonial angle to the gonial angle, and that in sagittal plane was 2.4 ± 0.88 mm (range, -3 to 4.4 mm) from the anterior inferior mandibular border to the center point on the condylar head to the condylar head line. The whole 3-dimensional deviation was 1.2 ± 1.7 mm in all patients.

CONCLUSION

Well-designed splints can assist in precise mandibular reconstruction with high efficiency and accuracy, and thus are a reliable method for complicated second-stage mandibular reconstruction. However, to achieve a better outcome, a satisfactory design is required to adapt the complicated and varied defect.

Development of customized implant and customized surgical osteotomy guide in ablative tumor surgery for accurate mandibular reconstruction

OBJECTIVES

The objective of this study was to provide the generalized methodology for design and development of a customized implant and customized surgical osteotomy guide (CSOG) for precise mandibular tumor resection and placement of a customized implant in ablative tumor surgery for accurate mandibular reconstruction.

METHODS

Medical imaging technique, image processing, virtual surgical planning (VSP), biomedical computer-aided design (CAD), and rapid prototyping (RP) were used to develop CSOG and customized implant. A mock surgical test and an experimental analysis were performed on the biomodel (RP assisted diseased model) to check the effectiveness of the CSOG.

RESULTS

The paired t test showed the statistically significant result with the use of CSOG as compared to the without using CSOG in ablative mandibular tumor surgery.

CONCLUSIONS

A mock test and an experimental analysis proved that, the precise tumor resection and customized implant placement with minimal gap between bone-implant junctions in mandibular reconstruction using CSOG.

Engineering the Interface: Nanodiamond Coating on 3D-Printed Titanium Promotes Mammalian Cell Growth and Inhibits Staphylococcus aureus Colonization

Additively manufactured selective laser melted titanium (SLM-Ti) opens the possibility of tailored medical implants for patients. Despite orthopedic implant advancements, significant problems remain with regard to suboptimal osseointegration at the interface between the implant and the surrounding tissue. Here, we show that applying a nanodiamond (ND) coating onto SLM-Ti scaffolds provides an improved surface for mammalian cell growth while inhibiting colonization of Staphylococcus aureus bacteria. Owing to the simplicity of our methodology, the approach is suitable for coating SLM-Ti geometries. The ND coating achieved 32 and 29% increases in cell density of human dermal fibroblasts and osteoblasts, respectively, after 3 days of incubation compared with the uncoated SLM-Ti substratum. This increase in cell density complements an 88% reduction in S. aureus detected on the ND-coated SLM-Ti substrata. This study paves a way to create facile antifouling SLM-Ti structures for biomedical implants.

Clinical Application of Temporary External Fixator for Immediate Mandibular Reconstruction

Immediate mandibular reconstruction is always necessary for the patients receiving segmental mandibulectomy to recover the facial contour and function of occlusion. When 3D modeling is unavailable, temporary external fixator is necessary to maintain the occlusion relationship and facial contour. In this study, we introduce the clinical application of temporary external fixator for immediate mandibular reconstruction in patients receiving segmental mandibulectomy, which consists of 2 anchor claws, 2 all-round retentive arms, and 1 central locking structure. From August 2016 to September 2017, temporary external fixator was applied in 13 patients. Clinical data of gender, age, surgical procedure, duration of operation, and clinical outcomes were recorded and analyzed. Among the 13 patients, there were 4 men and nine women whose ages ranged from 21 to 64 (mean 47.7) years old. There were 9 benign and 4 malignant lesions. All lesions expended at the buccal side of mandible. 12 fibular flaps and 1 vascularized iliac bone graft were used. The mandibular defect ranged from 6 to 14 (mean 10) cm. The operation duration of surgery ranged from 5 to 10 (mean 7) hours. All flaps survived with primary healing. The occlusion and facial contour were good, without significant changes of the length of mandibular body and width of mandible before and after surgery. No functional sequelae were noted at the donor sites. From these results, the temporary external fixator is easy to operate; the surgical procedure is simple and time-saving for surgeon when 3D modeling is unavailable. The indication for temporary external fixator usage is the mandibular lesion growing outward to cheek soft tissue.

Development and preliminary evaluation of an autonomous surgical system for oral and maxillofacial surgery

BACKGROUND

Human-related factors affect the accuracy and safety of the oral and maxillofacial surgery (OMS). This study proposed an autonomous surgical system aiming to conduct the OMS under the assistance and surveillance of the surgeon.

METHODS

A markerless navigation module and a compact OMS robot were seamlessly integrated into this system. The specifications of each module and the working concept of the system were elaborated in this paper. A drilling experiment was conducted on five 3D-printed mandible models to test the pose detecting capability and evaluate the operational performance.

RESULTS

The experiment showed that this system could successfully guide the robot finishing the operation regardless of the mandible pose. The accuracy of software and hardware are acceptable and potential performance improvement can be achieved in positioning accuracy.

CONCLUSION

This system proposed a novel concept and a practical solution to decrease the human-related factors on the OMS, which may change the role of the surgeon in the future operating room and finally benefit the outcomes of OMS.

An analysis of approach toward oral and maxillofacial surgery: A survey of 1800 health-care specialists, students, and general people in Odisha, India

Aim:

The aim of the study is to assess the perception of oral and maxillofacial surgery (OMFS) by health-care professionals, students, and general public in the state of Odisha, India.

Materials and Methods:

A questionnaire form was formatted that listed ten clinical situations and given by hand to 1800 individuals, divided into six groups: Group I – general medical practitioners; Group II – specialties of dentistry; Group III – general dental practitioners; Group IV – medical students; Group V – dental students; and Group VI – general public, each comprising 300 individuals. Respondents were asked to indicate who they would expect to treat them if they had one of the specified conditions listed in the questionnaire. We present the results and current awareness levels of this simple questionnaire and in due course educate and inform the society about the treatment OMFS provides.

Results:

Most of the respondents in Groups II, III, and V agreed that specific conditions listed in the questionnaire were within the domain of OMFS, but such response was not seen in Groups I, IV, and VI (P < 0.05). An overall awareness level of OMFS was found to be 50.8%.

Conclusion:

The liability and responsibility of creating and improving the awareness and perception of our specialty lies on oral and maxillofacial surgeon. Unified efforts at individual as well as global level will help achieve this goal.

What Surgical Education the Speciality Offers? Perception of Role of Oral and Maxillofacial Surgery by 1200 Healthcare Professionals, Students and the General Public in Hyderabad, India

Aim

To investigate the perception of Oral and maxillofacial surgery by healthcare professionals, students and general public.

Materials and Methods

A questionnaire form was created that listed ten clinical situations, and given by hand to 1200 individuals, divided into six groups: group 1, medical professionals; group 2, Specialties of dentistry; group 3, general dentists; group 4, medical students; group 5, dental students; and group 6, general public, each comprising 200 individuals. Respondents were asked to indicate who they would expect to treat them if they had one of the specified conditions listed in the questionnaire. We present the results and current awareness levels of this simple questionnaire. The present study addresses the common issue raised by many authors, 'What surgical education the speciality offers?' especially to medical professionals, medical students and general public to enhance an appropriate referral.

Results

Most of the respondents in groups 2, 3 and 5 agreed that specific conditions listed in the questionnaire were within the domain of oral and maxillofacial surgery, but such response was not seen in groups 1, 4 and 6 (p < 0.001). An overall awareness level of oral and maxillofacial surgery was found to be 50.2%.

Conclusion

The onus of creating and improving the awareness and perception of our specialty lies on oral and maxillofacial surgeon. Unified efforts at individual as well as global level will help achieve this goal.

Soft Tissue Engineering

There is a recognized need to reconstruct and restore complex craniomaxillofacial soft tissues. The objective of this article is to focus on the role that tissue engineering/regenerative medicine can play in addressing various barriers (vascularity, tissue bulk, volitional control, and esthetics) and impediments (timing, regional applicability/dissemination, and regulation by the US Food and Drug Administration) to optimal tissue reconstruction of complex soft tissue structures. We will use the lips as an example to illustrate our points.

Potential new method of design for reconstruction of complicated mandibular defects: a virtual deformable mandibular model

The treatment of complicated mandibular defects, including misshaped and missing bones, is challenging, and the success of reconstruction depends to a large extent on the formulation of a precise surgical plan. There is still no ideal preoperative method of design for reconstruction to deal with large, cross-midline, mandibular, segmental defects. We have built a virtual deformable mandibular model (VDMM) with 3-dimensional animation software. Sixteen handles were set on the model, and these could be easily controlled with a computer mouse to change the morphology of the deformable mandibular model. The computed tomographic (CT) data from 10 normal skulls was used to validate the adjustability of the VDMM. According to the positions of the mandibular fossa of the temporomandibular joint, the maxillary dental arch, and the craniomaxillofacial profile, the model could be adjusted to an ideal contour, which was coordinated with the skull. The VDMM was then adjusted further according to the morphology of the original mandible. A 3-dimensional comparison was made between the model of the deformed mandible and the original mandible. Using 16 control handles, the VDMM could be adjusted to a new outline, which was similar in shape to the original mandible. Within 3mm deviation either way, the absolute mean distribution of deviation between the contour of the deformed model and the original mandible was 92.5%. The VDMM might be useful for preoperative design of reconstruction of complicated mandibular defects.

Intraoperative frozen section histological analysis of resection samples is useful for the control of primary lesions in patients with oral squamous cell carcinoma

To ensure reliable surgical margins, intraoperative frozen section histological analysis (FS) has been performed since October, 2005 as follows: i) the orientation at the anatomical position and extent of the tumor are shared between oral pathologists and oral surgeons using imaging evaluations and pathological pictures and the planned site of sampling for intraoperative FS is confirmed; ii) a tumor team is organized and the team marks the tumor area and sets the resection range to correct the setting errors of the resection range among operators; iii) vital Lugol staining is applied to the lesion prior to tumor resection, the surgical margin is set based on the non-stained region and the extent of the tumor is macroscopically confirmed in the maximum cross-sectional surface of the resected specimen; and iv) FS is performed using samples from resected specimens to confirm the mucoepithelium and safety margin of the deep stump. The aim of this study was to evaluate the usefulness of our FS method. The treatment outcomes of oral squamous cell carcinoma were retrospectively investigated in patients treated prior to (Group 1) and after (Group 2) the introduction of our FS method. The recurrence rate of the primary lesions was high (17.3%) in Group 1, but decreased significantly in Group 2 (6.9%). Regarding clinicopathological factors, the condition of the surgical margins was associated with recurrence of the primary lesion in Group 1, but not in Group 2. In conclusion, our FS method appears to be useful for resecting tumors with reliable safety margins.

Technical procedures for template-guided surgery for mandibular reconstruction based on digital design and manufacturing

BACKGROUND

The occurrence of mandibular defects caused by tumors has been continuously increasing in China in recent years. Conversely, results of the repair of mandibular defects affect the recovery of oral function and patient appearance, and the requirements for accuracy and high surgical quality must be more stringent. Digital techniques--including model reconstruction based on medical images, computer-aided design, and additive manufacturing--have been widely used in modern medicine to improve the accuracy and quality of diagnosis and surgery. However, some special software platforms and services from international companies are not always available for most of researchers and surgeons because they are expensive and time-consuming.

METHODS

Here, a new technical solution for guided surgery for the repair of mandibular defects is proposed, based on general popular tools in medical image processing, 3D (3 dimension) model reconstruction, digital design, and fabrication via 3D printing. First, CT (computerized tomography) images are processed to reconstruct the 3D model of the mandible and fibular bone. The defect area is then replaced by healthy contralateral bone to create the repair model. With the repair model as reference, the graft shape and cutline are designed on fibular bone, as is the guide for cutting and shaping. The physical model, fabricated via 3D printing, including surgical guide, the original model, and the repair model, can be used to preform a titanium locking plate, as well as to design and verify the surgical plan and guide. In clinics, surgeons can operate with the help of the surgical guide and preformed plate to realize the predesigned surgical plan.

RESULTS

With sufficient communication between engineers and surgeons, an optimal surgical plan can be designed via some common software platforms but needs to be translated to the clinic. Based on customized models and tools, including three surgical guides, preformed titanium plate for fixation, and physical models of the mandible, grafts for defect repair can be cut from fibular bone, shaped with high accuracy during surgery, and fixed with a well-fitting preformed locking plate, so that the predesigned plan can be performed in the clinic and the oral function and appearance of the patient are recovered. This method requires 20% less operating time compared with conventional surgery, and the advantages in cost and convenience are significant compared with those of existing commercial services in China.

CONCLUSIONS

This comparison between two groups of cases illustrates that, with the proposed method, the accuracy of mandibular defect repair surgery is increased significantly and is less time-consuming, and patients are satisfied with both the recovery of oral function and their appearance. Until now, more than 15 cases have been treated with the proposed methods, so their feasibility and validity have been verified.

Biomechanical analysis of a curvilinear distractor device for correcting mandibular symphyseal defects

PURPOSE

The local mechanical environment is a determinant of successful transport disc distraction osteogenesis. This study assessed the biomechanics of a curvilinear distractor device for correcting mandibular symphyseal defects.

MATERIALS AND METHODS

The finite element method was used to analyze an intact mandible, mandibular distractor bodies with different rail thicknesses (4, 6, 8, and 10 mm), and mandibular distractor bodies with rails and auxiliary lingual brackets.

RESULTS

Rail thickness was positively correlated with maximum von Mises stress in the distractor and negatively correlated with maximum displacement of the mandibular distractor bodies. The maximum von Mises stress occurred at the junction of the rails and fixed arms. It also exceeded the yield strength of the titanium material. Compared with the maximum displacement of the intact mandible, that of the mandibular distractor bodies was visibly increased.

CONCLUSION

An auxiliary lingual bracket can effectively decrease stress in such devices and displacement of mandibular distractor bodies. Rail fixation alone cannot achieve stability for distraction osteogenesis. Using an auxiliary lingual bracket effectively prevents distractor breakage and exposure.

Factors influencing the necessity for preoperative vascular imaging before harvesting a vascularized fibular flap

OBJECTIVE

This study was carried out to identify groups of patients who would benefit from this angiography. The angiographic images of a random group of patients were studied; the correlations between the vascular state of the lower extremities and vessel pathology were investigated; and the possible links of these findings with certain medical conditions were explored.

STUDY DESIGN

Three experienced observers independently evaluated the angiograms of 185 patients. The status of all 3 vessels of the lower extremities (anterior tibial artery, posterior tibial artery, and peroneal artery) was evaluated. The patients' gender, age, drinking and smoking habits, and medical conditions were documented.

RESULTS

We found a significant correlation between pathology of the arteries of the lower extremity and blood cholesterol level, blood pressure, coronary heart disease, diabetes mellitus, and age.

CONCLUSIONS

We suggest that preoperative vascular imaging be carried out in patients with comorbidities to reduce the potential for flap failure and to minimize donor site complications.

Influence of caffeic acid phenethyl ester on bone healing in a rat model

OBJECTIVE

To examine the effects of caffeic acid phenethyl ester (CAPE; a component of honey bee-hive propolis with antioxidant, anti-inflammatory, antiviral and anticancer properties) on bone regeneration and fibrotic healing in a rat model.

METHODS

Male Sprague-Dawley rats (n = 63; mean age 7 weeks; weight 280-490 g) were randomly divided into three groups: A, cranial defect with no bone healing treatment (n = 21); B, cranial defect treated with CAPE (n = 21); C, cranial defect treated with CAPE and β-tricalcium phosphate/hydroxyl apatite (n = 21). Rats were anaesthetized with ketamine (8 mg/100 g) by intraperitoneal injection and a cranial critical size bone defect was created. Following surgery, CAPE (10 µmol/kg) was administered by daily intraperitoneal injection. Seven rats in each group were killed at days 7, 15 and 30 following surgery. Bone regeneration, fibrotic healing and osteoblast activity were evaluated by histopathology.

RESULTS

Statistically significant differences in healing were found between all groups. There were no statistically significant within-group differences between day 7 and 15. At day 30, bone healing scores were significantly higher in groups B and C compared with group A.

CONCLUSION

CAPE significantly improved bone-defect healing in a rat model, suggesting that CAPE has beneficial effects on bone healing.

Dynamic reanimation for facial palsy: an overview

Facial paralysis can have a profound effect on the patient from both an aesthetic and functional point of view. The symptoms depend on which branch of the nerve has been damaged and the severity of the injury. The purpose of this paper is to review currently available treatments for dynamic reanimation of a damaged facial nerve, and the goals are a symmetrical and coordinated smile. Careful selection of patients and use of the appropriate surgical technique can have excellent results.