Cost-effective patient-specific intraoperative molded cranioplasty

Intraoperative molding of polymethyl-methacrylate into complex three-dimensional shapes with correct thickness is often a time-consuming process and may lead to unsatisfying cosmetical results. This article describes an intraoperative technique to assemble a polymethyl-methacrylate implant as a replica of the patient's bone flap. This approach provides a fast and inexpensive alternative technique with good cosmetic outcome. The technique is feasible and can be applied in early and delayed cranioplasty procedures. In selected patients, immediate single-stage reconstruction avoids a second operation.     

Indications and limitations of intraoperative navigation in maxillofacial surgery.

PURPOSE: Although primarily developed for neurosurgical application, intraoperative navigation has gained acceptance even in maxillofacial surgery with an increasing field of indications. We want to demonstrate our clinical experiences, focusing on the indications and limitations of intraoperative navigation. MATERIALS AND METHODS: In our department, the navigation system VectorVision (BrainLAB, Heimstetten, Germany) is used. The accuracy of this referencing method, consisting of a cortical fixed reference system and surface scanning, was checked by anatomic landmarks. Surgical treatment of 20 patients was performed with the help of the navigation system. RESULTS: The VectorVision system proved to be a useful supplement during the surgical exploration of complex anatomic regions. However, resolution of imaging data sets, errors of image fusion, and discrepancies during referencing increased the inaccuracy before surgery. The main problem was the topographic changes caused by surgery, resulting in discrepancies between the preoperative image data and the surgical site. In one case suffering from a meningioma extending to the neck, topography was changed by surgery making navigation inaccurate. CONCLUSION: Generally, a promising field for intraoperative navigation systems were small surgical approaches allowing only limited exposure. From our point of view, additional promising indications include vast tumors or recurrent tumors because of altered anatomy with lost landmarks during surgery. The same was the case of patients suffering from plexiform neurofibroma caused by neurofibromatosis type I. Further, intraoperative navigation was helpful to determine the position of foreign bodies during imaging, making the intraoperative location easier.     

Bone growth factors in maxillofacial skeletal reconstruction

A literature review was performed to survey the available information on the potential of bone growth factors in skeletal reconstruction in the maxillofacial area. The aim of this review was to characterize the biological and developmental nature of the growth factors considered, their molecular level of activity and their osteogenic potential in craniofacial bone repair and reconstruction. A total of 231 references were selected for evaluation by the content of the abstracts. All growth factors considered have a fundamental role in growth and development. In postnatal skeletal regeneration, PDGF plays an important role in inducing proliferation of undifferentiated mesenchymal cells. It is an important mediator for bone healing and remodelling during trauma and infection. It can enhance bone regeneration in conjunction with other growth factors but is unlikely to provide entirely osteogenic properties itself. IGFs have an important role in general growth and maintenance of the body skeleton. The effect of local application of IGFs alone in craniofacial skeletal defects has not yet shown a clear potential for enhancement of bone regeneration in the reported dosages. The combination of IGF-I with PDGF has been effective in promoting bone regeneration in dentoalveolar defects around implants or after periodontal bone loss. TGFbeta alone in skeletal reconstruction appears to be associated with uncertain results. The presence of committed cells is required for enhancement of bone formation by TGFbeta. It has a biphasic effect, which suppresses proliferation and osteoblastic differentiation at high concentrations. BMPs, BMP2, BMP4 and BMP7 in particular, appear to be the most effective growth factors in terms of osteogenesis and osseous defect repair. Efficacy of BMPs for defect repair is strongly dependent on the type of carrier and has been subject to unknown factors in clinical feasibility trials resulting in ambiguous results. The current lack of clinical data may prolong the period until this factor is introduced into routine clinical application. PRP is supposed to increase proliferation of undifferentiated mesenchymal cells and to enhance angiogenesis. There is little scientific evidence about the benefit of PRP in skeletal reconstructive and preprosthetic surgery yet and it is unlikely that peri-implant bone healing or regeneration of local bone into alloplastic material by the application of PRP alone will be significantly enhanced.     

Protraction of the maxillofacial complex

The purpose of this study was to evaluate the orthopedic effects of reverse headgear therapy in children with skeletal Class III malocclusions. Data based on pretreatment and posttreatment lateral cephalometric radiographs of seven boys and five girls, ages 4 through 14 years, were used. Comparison of the pretreatment and posttreatment cephalograms revealed a significant (p less than 0.05) increase in the SNA angle that indicated the maxilla was positioned farther forward after reverse headgear therapy. Both the maxillary and the mandibular effective lengths increased significantly from pretreatment to posttreatment, as did anterior and posterior total face height. These linear increases are most likely a reflection of growth rather than a direct result of the therapy. There was no significant change in the anteroposterior position of the mandible, although there was a tendency for the mandibular plane angle and the gonial angle to decrease. The results of this study indicate that maxillary protraction with a reverse headgear should be considered an alternative to orthognathic surgery in the treatment of children and adolescents with skeletal Class III malocclusion characterized by maxillary retrognathism.     

术中CT在颌面部骨折手术治疗中的应用

目的:比较应用术中CT与传统方法手术治疗颌骨骨折的效果,探讨术中CT在颌面部复杂骨折手术中的应用价值。方法:回顾分析2016年7月—2018年3月完成手术治疗的87例颌面部骨折患者的临床资料。按照术中是否应用CT分为2组,术中CT组41例,对照组（非术中CT）46例。分析一般资料特点,比较2组病例手术相关指标和术后效果。采用SPSS 22.0软件包对数据进行统计学处理。结果:与对照组相比,术中CT组平均术中修正次数较高（修正率29%）,平均复位偏差更小,且获得满意度更高;但2组在患者性别、年龄、骨折类型、接骨板数目、手术时间、住院天数、费用、感染率等方面无显著差异。结论:术中CT辅助下进行的复杂颌面部骨折复位固定术具有较高精确度,与传统手术方法相比,能提高治疗效果。     

Critical appraisal of patient-specific implants for secondary post-traumatic orbital reconstruction

In orbital reconstruction, a patient-specific implant (PSI) may provide accurate reconstruction in complex cases, since the design can be tailored to the anatomy. Several design options may be embedded, for ease of positioning and precision of reconstruction. This study describes a cohort of 22 patients treated for secondary orbital reconstruction with a PSI; one patient received two PSI. The preoperative clinical characteristics and implant design options used are presented. When compared to preoperative characteristics, the postoperative clinical outcomes showed significant improvements in terms of enophthalmos (P < 0.001), diplopia (P < 0.001), and hypoglobus (P = 0.002). The implant position in all previous reconstructions was considered inadequate. Quantitative analysis after PSI reconstruction showed accurate positioning of the implant, with small median and 90th percentile deviations (roll: median 1.3°, 90th percentile 4.6°; pitch: median 1.4°, 90th percentile 3.9°; yaw: median 1.0°, 90th percentile 4.4°; translation: median 1.4 mm, 90th percentile 2.7 mm). Rim support proved to be a significant predictor of roll and rim extension for yaw. No significant relationship between design options or PSI position and clinical outcomes could be established. The results of this study show the benefits of PSI for the clinical outcomes in a large cohort of secondary post-traumatic orbital reconstructions.     

Analysis of intraoral microvascular anastomosis in maxillofacial defects reconstruction

This review summarizes the research progress in the field of intraoral microvascular anastomosis techniques (IAT) and attempts to investigate the indications for procedures in which IAT can be applied, the surgical procedure and the difficulties involved, technical assessments, result evaluation and the perspective. Currently, microvascular anastomosis technique is widely used in maxillofacial defects reconstruction from various causes including cutaneous injury or congenital deformity which usually required extensive flap reconstruction and therefore a vascular free flap is routinely used. Conventional microvascular anastomosis reconstruction techniques cannot avoid new incisions, which will affect the postoperative aesthetic situation. Surgeons have therefore attempted to improve this technique to effectively eliminate scars caused by surgery: some patients can be chosen to undergo microvascular anastomosis of the free flap intraorally, thus reducing the extraoral incision caused by the anastomosis located in neck or maxillofacial improving the postoperative appearance of the patients. In addition to preserving the external appearance, intraoral anastomosis technique (IAT) can also solve some other problems of maxillofacial vascular anastomosis, such as insufficient vessel pedicle length and high risk of facial nerve injury.     

Oral maxillofacial reconstruction: 25 years'''' experience

Purpose: To make a retrospective analysis of the reconstructive cases with oral maxillofacial defects of 25 years in the department.     

Temporalis myofascial flap for maxillofacial reconstruction.

To date, the temporalis myofascial flap has been used only to a limited extent for reconstruction in the maxillofacial region. Experience gained with 26 temporalis flaps in reconstruction of tissue defects in the periorbital region, skull base, maxilla, and oral cavity is presented. Only one patient developed total necrosis of the flap; significant necrosis did not occur in any other patient. The anatomy of the flap and surgical technique are briefly presented.     

Navigation-assisted maxillofacial reconstruction: accuracy and predictability

The aim of this study was to evaluate the accuracy of navigation-assisted maxillofacial reconstruction and to identify the predictors of the clinical outcomes. A total of 112 patients who underwent navigation-assisted maxillofacial reconstruction with free flaps between 2014 and 2019, performed by a single surgical team, were assessed. Accuracy was evaluated by superimposing the postoperative computed tomography data with the preoperative virtual surgical plan. Predictors of the clinical outcomes affecting the accuracy were identified and analysed. The mean deviation and root mean square (RMS) estimate of the orbital, maxillary, and mandibular reconstructions were 0.88 ± 3.25 mm and 3.38 ± 0.73 mm, 0.77 ± 3.44 mm and 3.69 ± 0.82 mm, and 1.07 ± 4.16 mm and 4.67 ± 3.95 mm, respectively (P < 0.05). There was no significant difference in orbital volume or projection between the preoperative, postoperative, and healthy orbits (P = 0.093 and P = 0.225, respectively). Multivariate linear regression analysis confirmed significant associations between the accuracy of navigation-assisted mandibular reconstruction and preservation of the condyle, type of reconstruction, type of osteosynthesis plate, and number of bony segments. Navigation-assisted midface reconstruction yielded a higher level of accuracy in the final surgical outcome when compared to mandibular reconstruction. Computer-assisted techniques and intraoperative navigation can be an alternative or adjunct to current surgical techniques to improve the final surgical outcome, especially in more complex maxillofacial reconstructions.     

State-of-the-art materials used for maxillofacial prosthetic reconstruction

The present state-of-the-art rests primarily on three general types of polymeric materials based on chemical configurations, that of polyacrylates, polydimethylsiloxane, and segmented block polyetherurethanes. Each of these types is currently prominent in a wide range of dental prosthodontics and surgical prosthetics with continued chemical variants emerging to attain enhanced biocompatibility for safety and effectiveness. However, owing to the disproportionally lower demand, the state-of-the-art for maxillofacial restorative prosthetics has not focused adequately on the specific array of the properties needed for the ideal prosthesis. To approach the ideality will require synthesizing new molecular configurations adjusted with component structures either as block copolymers or as intermediate oligomers. The synthetic effects must have a comprehensive plan of immediate assessments on terms of biocompatibility for safety to orofacial tissues and effective durability against all conceivable deterioration of the chemical structure. Above all, inasmuch as the skilled art and techniques of maxillofacial prosthetics is a custom-made specialty allied to the prosthodontics, the improved material for ideality should be readily amenable to molding by the well-established dental stone mold technology, for reasons of cost and simplicity.     

Perioperative management of maxillofacial tumor and reconstruction patients

Patients who undergo maxillofacial tumor surgery and reconstruction present many perioperative management challenges. This patient population commonly presents with significant medical comorbidities in addition to the site-specific challenges of these tumors and the complexity of the reconstructive surgeries. This article combines a review of the relevant literature and the experience of a busy regional maxillofacial tumor and reconstruction referral center to provide a concise reference for management of patients. In addition to the valuable system-specific information presented, the article outlines a daily clinical pathway, which is easily adapted to any clinical practice performing complex maxillofacial surgery.     

Intraoperative real-time navigation and intraoperative three-dimensional imaging for patient-specific total temporomandibular joint replacement

Customized solutions for replacement of the temporomandibular joint (TMJ) along with surgical guides enable precise and fast transfer of the virtual plan to the patient. However, these guides lack information on screw vectors and length, and well-defined borders for bony resections towards the medial skull base. This retrospective study was performed to investigate the feasibility and benefit of real-time navigation and intraoperative three-dimensional imaging during total TMJ replacement (TJR), as well as patient clinical outcomes. Between 2016 and 2020, 26 customized prostheses were implanted in 21 patients either with or without real-time navigation and instrument tracking. The clinical, surgical, radiological, and navigational data were analysed. The accuracy of navigation registration with instrument tracking, precision of screw insertion, and implant and screw positions were analysed by fusion of the virtual plan and surgical outcome. Real-time navigation aided orientation during lateral skull base dissection and resection. However, the results of real-time navigation-aided drilling were inconclusive regarding vector and length control. At a mean 15.3 ± 3.0 months of follow-up, average mouth opening had improved from 21.69 ± 2.80 mm to 36.40 ± 1.25 mm; the average pain score decreased from 6.18 ± 0.74 to 1.06 ± 0.52. Thus, intraoperative real-time navigation for TJR assists lateral skull base dissection and resection.     

颌面部爆炸伤软组织缺损早期修复的实验研究

目的：研究颌面部爆炸伤软组织缺损早期修复的可行性。方法：15只犬随机分为A（6h)组，B（72h）组。采用雷管爆炸模拟爆炸性武器产生的冲击波，滑膛枪发射钢珠模拟爆炸破片，在同步系统控制下致犬左咬肌区破－冲复合伤软组织缺损。A组伤后6h初次清创后组织缺损立即用组织瓣游离移植修复，B线伤后72h二次清创后同样方法修复，观察术后皮瓣成活情况。结果：A组3次均失败。B组12例，成功9例，皮瓣成活率75％。结论：颌面部爆炸伤软组织缺损经初期清创，72h二次扩创早期修复是可行的，吻合血管游游组织瓣移植是早期修复该种缺损的有效方法之一。