Evaluation of fit feasibility of stock total joint replacement in temporomandibular joint ankylosis patients

Long standing adult temporomandibular joint ankylosis (TMJA) results in smaller ramal height, and warped and undulated ramus. Despite the efforts made to standardise the sizes available in stock joint (Zimmer Biomet®), the system causes fit challenges in TMJA patients. The aim of the study was to evaluate the virtual feasibility of stock prostheses in TMJA patients. The data included amount of bone contouring for fossa placement, available ramal length, length discrepancy if placed straight, angulation of mandibular component required to adapt to the bone, and mediolateral fit discrepancy. CT data of 50 TMJA patients (71 joints; unilateral, n = 29; bilateral, n = 21; male, n = 33; female, n = 17) with mean age of 24.26 ± 8.88 years were included. 53 joints required more than 3 mm lateral bone reduction for fossa placement. The ramal length were categorised into ranges 35–40 mm (n = 15), 41–45 mm (n = 14), 46–50 mm (n = 28) and >50 mm (n = 14). Correlation between the age of occurrence of ankylosis and ramal length using the Pearson correlation coefficient revealed a positive correlation (r = 0.38, p = 0.001). Length discrepancy, angulation of mandibular component, and mediolateral fit discrepancy decreases as the ramal length increases. Only 14 joints had appropriate fit of stock prostheses while the remaining 57 joints warranted compromised placement. Even the smallest available stock mandibular component (45 mm) had a compromised fit in terms of length and adaptability on the lateral aspect of ramus. The study concludes that a short ramus is mostly limiting factor in using stock prosthesis in TMJA patients. There is a need for still smaller size stock prostheses.     

Development of a patient-specific temporomandibular joint prosthesis according to the Groningen principle through a cadaver test series

Objectives

Patients suffering from osteoarthritis, ankylosis (e.g. post-trauma or tumour) in the temporomandibular joint (TMJ) can present with symptoms such as severely restricted mouth opening, pain or other dynamic restrictions of the mandible. To alleviate the symptoms, a total joint prosthesis can be indicated, such as the Groningen TMJ prosthesis. This was developed as a stock device with a lowered centre of rotation for improved translational and opening capacity. This study aimed to improve the design of the prosthesis, and produce a workflow for a customized Groningen TMJ prosthesis, in order to make it more accurate and predictable.

Accuracy of patient-specific temporal implants using PEKK

The main aim of this study was to evaluate the accuracy of immediate CAD/CAM reconstruction of the temporal hollowing following temporalis muscle surgery, using a patient-specific implant (PSI) PEKK model.This case series included ten patients who underwent maxillofacial reconstruction using temporalis muscle flap (TMF). The study involved the preoperative planning and fabrication of the temporal implant using virtual surgical planning software. The planning was based on multislice CT scans, from which DICOM files were used to fabricate a 3D model of the temporalis muscle using polyetherketoneketone (PEKK). The patients were followed up for 12 months, to check for any signs of infection or mobilization, and to assess accuracy. At the end of the follow-up period, all the patients showed acceptance of the external appearance, with no signs of infection or rejection. These customized implants were measured and compared with their original 3D preoperative planning using a point-based analysis. This revealed a mean difference (±SD) of 0.0373 (±0.3036) mm and a median difference (Q1 to Q3) of 0.0809 (−0.2108 to 0.2769) mm. The study demonstrated that a highly accurate duplication of PSIs can be achieved using this template-molding workflow.The use of PEKK PSIs resulted in uneventful healing and esthetic acceptance by the patients and, therefore, is a relevant treatment option when temporal hollowing has to be corrected.     

氧化锆个性化基台与钛基边缘适合性研究

目的比较不同品牌的CAD/CAM氧化锆个性化基台与钛基之间的适合性。方法用CAD/CAM分别设计和加工3种氧化锆个性化基台(日进、爱尔创和卡瓦),每种5个。通过扫描电子显微镜,测量氧化锆个性化基台与钛基之间的边缘间隙(MG),比较3种氧化锆个性化基台与钛基之间的边缘适合性。结果卡瓦组(7.19±2.98)μm与日进组(10.25±6.25)μm和爱尔创组(9.87±5.48)μm的边缘间隙的差异具有统计学意义(P<0.05);爱尔创组与日进组的边缘间隙的差异无统计学意义(P>0.05)。结论不同的材料直接影响个性化基台与钛基之间的适合性。在个性化基台与钛基的边缘适合性方面,卡瓦氧化锆明显优于日进及爱尔创氧化锆。     

Preliminary clinical study of Chinese standard alloplastic temporomandibular joint prosthesis

Purpose

To evaluate the preliminary clinical outcomes on the Chinese standard temporomandibular joint (TMJ) prostheses.

人工颞下颌关节治疗关节强直的效果分析

目的 应用并评价Biomet标准型人工颞下颌关节假体治疗关节强直的效果。方法 回顾2013—2015年收治的颞下颌关节强直患者,采用计算机辅助设计和制作技术,设计并制作强直骨球切除和Biomet标准型人工颞下颌关节假体安放导板,术中应用下颌下切口取出的皮下游离脂肪移植于髁突假体周围,预防异位成骨。对于合并严重颌骨畸形的患者,采用人工关节假体延长前徙下颌支及Le Fort I型截骨术,数字化板辅助固定的方法同期矫正颌骨畸形。术后进行1年以上的临床和CT随访,评价开口度、咬合稳定性,以及假体周围有无异位成骨和假体与骨的结合情况。结果 11例患者15侧关节纳入研究,其中4例患者行下颌骨延长及颏后缩畸形纠正术。术后平均随访22.9个月（12~31个月）,无假体感染、断裂和松动。患者开口度显著改善（术前平均5.5 mm,术后31.5 mm,P<0.05）。4例患者气道显著增宽。CT显示假体固定螺钉周围无骨吸收,人工髁突头周围无异位成骨。结论 人工颞下颌关节假体是治疗关节强直,特别是复发性强直的可靠方法,可同时纠正颌骨畸形,效果稳定。     

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外伤性颞下颌关节强直的手术方法主要有裂隙式关节成形术、插入式关节成形术及关节重建术。如何选择正确的手术方法和理想的插入材料,是手术成功的关键。术后有效的早期开口训练也是改善开口度的重要手段。本文就这些方面的新进展做一综述。     

Management of temporomandibular joint ankylosis type III: lateral arthroplasty as a treatment of choice

Many surgical techniques for the management of temporomandibular joint (TMJ) ankylosis have been described in the literature. The purpose of this study was to report our experience using a lateral arthroplasty technique in the management of type III ankylosis. The records of 15 patients treated for TMJ ankylosis at our institution between 2007 and 2011 were reviewed. Pre- and postoperative information collected included age, gender, aetiology, ankylosis type/classification, existing facial asymmetry, maximum pre- and postoperative mouth opening, complications, and recurrence of ankylosis. The mean maximum inter-incisal opening in the preoperative period was 12.9 mm and in the postoperative period was 36.2 mm. No major complication was observed in any patient. No recurrence was noted in any patient. Our working hypothesis was that for patients with ankylosis type III, the medially displaced condyle and disc can fulfil their role in mandibular function and growth after extirpation of the ankylozed mass. Although they are located in an awkward medial position, they should function exactly as they would after a properly treated, displaced condylar fracture.     

Interpositional arthroplasty of post-traumatic temporomandibular joint ankylosis: A modified method

The purpose of this study was to evaluate a modified method of interpositional arthroplasty for post-traumatic temporomandibular joint ankylosis.All patients were treated with a modified interpositional arthroplasty that included: navigation-assisted accurate bone dissection with minimal removal of only 5 mm of the ankylosed bony mass, novel application of bone wax and porcine acellular dermal matrix to prevent re-ankylosis, and a unique 3D-printed splint for occlusal stabilization and gap maintaining. The pre- and post-operative physical and radiological examinations of patients were recorded during routine follow-up visits. Postoperative follow-up visits lasted at least 12 months.Twelve patients, seven males and five females, ranging from 21 years to 59 years, were enrolled in this retrospective case series. All of the twelve patients with eighteen bony ankylosed temporomandibular joints were treated by our new method. The post-operative follow-up periods ranged from 1 year to 4 years. During the follow-up visits within at least 1 year, no one manifested re-ankylosis. The mean maximum incisor opening changed from 7.4 ± 5.3 mm (p < 0.001, before surgery) to 37.6 ± 3.9 mm (p < 0.001, last follow-up visit). No sign of post-operative infection or foreign body rejection was observed during the follow-up visits. The post-operative occlusal relationship was sound and stable.It is suggested that the modified method of interpositional arthroplasty provides favorable clinical and radiographic outcomes after a short-term follow up.     

Single stage treatment of ankylosis of the temporomandibular joint using patient-specific total joint replacement and virtual surgical planning

Ankylosis of the temporomandibular joint (TMJ) is a debilitating condition that can result in pain, trismus, and a poor quality of life. It can be caused by injury, infection, and rheumatoid disease. Current management includes gap arthroplasty, interpositional arthroplasty, and reconstruction. Traditionally, joints are reconstructed using stock implants, or the procedure is done in two stages with an additional computed tomography (CT) scan between the resective and reconstructive procedures and use of stereolithographic models to aid the design of the definitive prostheses. We describe a technique for the resection of ankylosis and reconstruction of the joint in a single operation using virtually designed custom-made implants. Five patients with ankylosis of the TMJ had a single stage operation with reconstruction between 2010 and 2012. All had preoperative high-resolution CT with contrast angiography. During an international web-based teleconference between the surgeon and the engineer a virtual resection of the ankylosis was done using the reconstructed CT images. The bespoke cutting guides and implants were designed virtually at the same time and were then manufactured precisely using computer-aided design and manufacture (CAD-CAM) over 6 weeks. After release of the ankylosis and reconstruction, the patients underwent an exercise regimen to improve mouth opening. Follow-up was for a minimum of 6 months. Four patients had one operation, and one patient had two. Median/Mean maximum incisal opening increased from 0.6 mm before operation to 25 mm afterwards (range 23–27), and there was minimal surgical morbidity. This new method effectively treats ankylosis of the TMJ in a single stage procedure. Fewer operations and hospital stays, and the maintenance of overall clinical outcome are obvious advantages.     

Navigation-guided gap arthroplasty in the treatment of temporomandibular joint ankylosis

Gap arthroplasty, used in the treatment of temporomandibular joint (TMJ) ankylosis, is challenging, requiring resecting of massive abnormal bone formation at the skull base with complex and distorted anatomy. This study evaluated the application of image-guided navigation to gap arthroplasty. Four gap arthroplasties were performed on patients with unilateral TMJ ankylosis under computer-assisted navigation guidance. After preoperative planning and 3-dimensional simulation, the normal anatomic structures of the TMJ were created by superimposing and comparing the unaffected and affected sides. The amount and range of ankylotic bone to be resected was determined and displayed. Registration achieved an accurate match between the intra-operative anatomy and the CT virtual images. Anatomic structures and the position of surgical instruments were shown real time on the screen. In all cases the accuracy of the system measured by the computer did not exceed 1 mm. No complications occurred and the mean minimal thickness of the skull base between middle cranial fossa and reconstructed glenoid fossa was 1.97 mm. Using image-guided navigation resulted in safe surgical excision of the bony ankylosis from the skull base. Navigation-guided resection of the ankylotic bone in the TMJ gap arthroplasty was a valuable and safe technique in this potentially complicated procedure.     

Gap arthroplasty of temporomandibular joint ankylosis by transoral access: a case series

This article describes a technique of gap arthroplasty in temporomandibular joint (TMJ) ankylosis performed by transoral access. The treatment of TMJ ankylosis by creating an adequate gap is of paramount importance in preventing any future recurrence and this can be achieved only when good access is gained to this complex anatomical joint. Five patients with TMJ ankylosis (eight TMJ) were treated by gap arthroplasty using an intraoral approach. The average mouth opening before surgery was 8.6 mm and the average mouth opening achieved postsurgery was 37.9 mm. The average follow-up time was 13 months and none of the patients had any recurrence or significant complications during or after surgery. Our technique relies on the use of a stable landmark to trace the superior-most extent of the ankylotic mass thereby facilitating the removal of the entire mass including the medial extent. We found that even though transoral access is technically challenging and took an average time of 84 min, it has many advantages over conventional extraoral approaches in terms of facial scars and facial nerve injury. The authors also emphasize the importance of good postoperative physiotherapy and presurgical patient counselling to prevent future recurrences.     

The use of TMJ Concepts prostheses to reconstruct patients with major temporomandibular joint and mandibular defects

Temporomandibular joint (TMJ) reconstruction may be required in complex cases in which there are additional mandibular or zygomatic arch defects. The reconstructive options include autogenous tissue, alloplastic material, or combinations of these. The authors describe 4 cases in which TMJ reconstruction was performed with TMJ Concepts customized joint prostheses. The prosthetic components were designed to restore major defects in the zygomatic arch and the mandibular ramus and body, including one case in which the mandibular component was used to restore total mandibular continuity. The prosthetic components used in these cases provided excellent anatomical reconstruction, and were a viable treatment option in cases in which the pathological process made autogenous grafts unsuitable. The prostheses have been functioning for up to 6 years. In one case a revision operation was required because the lack of a pterygomasseteric sling resulted in the condyle dropping out of the fossa. The authors’ clinical experience with these cases suggests that a customized prosthesis combined with TMJ reconstruction can be a reliable treatment alternative for bridging complex, major maxillo-mandibular defects.     

创伤性颞下颌关节强直

颞下颌关节（TMJ）强直是一种严重影响下颌运动的疾病,创伤是其常见的病因,但创伤如何引起TMJ强直的发生,目前尚未完全阐明,本文就创伤性颞下颌关节强直危险因素、发病机制假说进行综述。     

Accuracy of Virtually Planned and Template Guided Implant Surgery on Edentate Patients

Purpose: Scientific evidence regarding the accuracy of implants placed into patients by the aid of a surgical template is limited. The objective of the present study was to verify if any variation exists between virtually planned implants' position using a computer, compared with the subsequently clinically placed implants with the aid of a surgical template in the mandible and the maxilla. Material and Methods: A total number of 25 edentate jaws were treated with the aid of a surgical template. In total, 139 implants were inserted. Fifty implants were inserted in the mandible and 89 in the maxilla. A voxel‐based registration method was used to match two separate cone‐beam computed tomography scans of the patients. The implant positions were calculated and compared between the planned implants and the implants' clinical position after more than 1 year after surgery. The results included the linear differences in distance at the level of the hex, the apex, and the depth. The angular differences were presented in degrees. Results: Statistical results indicated some factors with significant deviations. The greatest errors were found when comparing between patients moving during the computed tomography scans and those that did not move. The results showed significant divergence at the level of the hex and apex of the implants. Conclusion: The hypothesis was rejected, as the statistical results indicated that there were significant differences between virtually planned implants' position and the final position of implants placed clinically.     

数字化导板在颞下颌关节强直保留髁突手术中的指导作用

目的 设计制作数字化导板（digital guide）,用于指导颞下颌关节强直（temporomandibular joint ankylosis,TMJA）外侧成形术（lateral gap arthroplasty,LAP）中髁突残余（residual condyle）的保留,并评价其应用效果。方法 收集2012年1月—2014年1月间收治的TMJA患者,选择骨球内侧存在髁突残余者纳入研究。采用 ProPlan CMF 1.4软件进行术前设计,明确骨球范围及其与髁突残余的关系,设计数字化导板并采用快速成型技术制作完成,术中用以指导骨球的截除。评价导板的就位情况及对重要解剖结构的保护。术后拍摄CT评价截骨效果并与手术设计进行拟合,评价导板的准确性。结果 5例7侧关节手术中,导板就位稳定,指导截骨准确,未伤及颅底和外耳道前壁,有效保护了内侧的髁突残余。术后CT显示截骨与术前设计的平均误差为1.044 mm。结论 数字化导板可以准确有效地指导强直骨球的切除,有效保护了髁突残余、颅底和外耳道。     

Computer-guided gap arthroplasty: a new approach to the execution of preplanned osteotomies for the treatment of bony ankylosis of the temporomandibular joint

The purpose of this study was to assess the efficacy of 3-dimensional, printed, patient-specific guides to direct virtual gap arthroplasties that were designed for five patients with advanced unilateral ankylosis of the temporomandibular joint. The guides were used to mimic the intraoperative creation of five preplanned osteotomies, as well as simulating the width and depth of the bone cleavage. The accuracy of the devices in guiding the surgical simulation was assessed by superimposing the preoperative and postoperative computed tomographic scans. The devices were easily put in place with smooth uniform surgical bone cleavage, and favourable postoperative outcomes. The statistical analysis between the planned and surgical gaps, showed that the difference in dimensions was not significant (p = 0.1018). The patient-specific gap arthroplasty was neither too near the skull base nor did it jeopardise the height of the mandibular ramus.     

Lemierre syndrome leading to ankylosis of the temporomandibular joint

Lemierre syndrome, also known as Lemierre's disease is a rare condition that was first described by Andre Lemierre in 1936. We present a case of a 3-year-old boy who presented with ankylosis of the right temporomandibular joint (TMJ) secondary to a mastoid infection as part of Lemierre syndrome. His ankylosis resulted in restricted mouth opening, which had a considerable impact on his speech and ability to eat. Surgical treatment comprising right coronoidectomy, gap arthroplasty of the TMJ, and interpositional fat grafting, enabled him to move his jaw and function has returned. This case report highlights the consequences of Lemierre syndrome and the need for clinicians to be aware of its features and the impact it may have on patients.     

Accuracy of guided biopsy of the jawbone in a clinical setting: A retrospective analysis

The aim of this study was to investigate the accuracy of a previously described technique for guided biopsy of osseous pathologies of the jawbone in a clinical setting. The data sets of patients who had undergone guided biopsy procedures were retrospectively examined for accuracy. Digital planning of the biopsies and manufacturing of the tooth-supported drilling template were performed with superimposed cone beam computed tomography and intraoral scans using implant planning software. After a trephine biopsy was taken using the template, the postoperative low-dose cone beam computed tomography was analyzed for accuracy using the planning software with the corresponding (digitally-planned) biopsy cylinder. The mean angular deviation was 4.35 ± 2.5°. The mean depth deviation was ?1.40 ± 1.41 mm. Guided biopsy seems to be an alternative to a conventional approach for minimally invasive and highly accurate jawbone biopsy.