Ensemble detection of hand joint ankylosis and subluxation in radiographic images using deep neural networks.

The modified total Sharp score (mTSS) is often used as an evaluation index for joint destruction caused by rheumatoid arthritis. In this study, special findings (ankylosis, subluxation, and dislocation) are detected to estimate the efficacy of mTSS by using deep neural networks (DNNs). The proposed method detects and classifies finger joint regions using an ensemble mechanism. This integrates multiple DNN detection models, specifically single shot multibox detectors, using different training data for each special finding. For the learning phase, we prepared a total of 260 hand X-ray images, in which proximal interphalangeal (PIP) and metacarpophalangeal (MP) joints were annotated with mTSS by skilled rheumatologists and radiologists. We evaluated our model using five-fold cross-validation. The proposed model produced a higher detection accuracy, recall, precision, specificity, F-value, and intersection over union than individual detection models for both ankylosis and subluxation detection, with a detection rate above 99.8% for the MP and PIP joint regions. Our future research will aim at the development of an automatic diagnosis system that uses the proposed mTSS model to estimate the erosion and joint space narrowing score.

Assessment of bony changes in temporomandibular joint in patients using cone beam computed tomography - a cross sectional study.

BACKGROUND AND AIM: The aim of this study is to evaluate the changes in the temporomandibular joint (TMJ) in patients with temporomandibular disorder (TMD) and the relationship between age, sex, and types of TMJ change using Cone Beam Computed Tomography (CBCT). METHODS AND MATERIAL: CBCT records of 200 patients (123 women and 67 men) were retrieved and assessed. Right and left TMJs were evaluated separately, resulting in a total of 400 TMJs. The images were analyzed using On demand 3D Application The radiographic findings were classified as erosion, proliferative changes mainly, including flattening and osteophytes of the condyle, sclerosis, Ely cyst, hypoplasia and hyperplasia of the condyles, ankylosis, and joint cavity. Data analysis was performed using descriptive statistics, paired T-tests, and repeated measure ANOVA (Analysis of Variance) in SPSS Software. RESULTS: The most prevalent types of condylar bony changes observed was osteophyte (63.5%) followed by flattening of the articular surface (42%), erosion (40%), ankylosis (10%) and sclerosis (10%). 7.5% of joints showed hyperplastic condyles but only 2% showed hypoplasia. The least prevalent change observed was Ely Cyst (1%). Osteophyte was the most prevalent change observed in all age groups and both sexes except for men aged 31 ~ 50, where flattening was more frequent. A statistically significant difference was found between sex and prevalence of erosion in the age group of 10 ~ 30 (P = 0.001); as well as between sex and condylar hyperplasia in the same age group. CONCLUSION: Based on the findings of this research, the prevalence of bony changes of TMJ from highest to lowest is as follows: osteophyte, flattening of the articular surface, erosion, ankylosis, sclerosis, hyperplastic condyles, hypoplastic condyles and Ely Cyst. CBCT is an accurate 3 dimensional imaging modality for assessment of TMJ bony structures.

Neural network algorithm for detection of erosions and ankylosis on CT of the sacroiliac joints: multicentre development and validation of diagnostic accuracy.

OBJECTIVES: To evaluate the feasibility and diagnostic accuracy of a deep learning network for detection of structural lesions of sacroiliitis on multicentre pelvic CT scans. METHODS: Pelvic CT scans of 145 patients (81 female, 121 Ghent University/24 Alberta University, 18-87 years old, mean 40 ± 13 years, 2005-2021) with a clinical suspicion of sacroiliitis were retrospectively included. After manual sacroiliac joint (SIJ) segmentation and structural lesion annotation, a U-Net for SIJ segmentation and two separate convolutional neural networks (CNN) for erosion and ankylosis detection were trained. In-training validation and tenfold validation testing (U-Net-n = 10 × 58; CNN-n = 10 × 29) on a test dataset were performed to assess performance on a slice-by-slice and patient level (dice coefficient/accuracy/sensitivity/specificity/positive and negative predictive value/ROC AUC). Patient-level optimisation was applied to increase the performance regarding predefined statistical metrics. Gradient-weighted class activation mapping (Grad-CAM++) heatmap explainability analysis highlighted image parts with statistically important regions for algorithmic decisions. RESULTS: Regarding SIJ segmentation, a dice coefficient of 0.75 was obtained in the test dataset. For slice-by-slice structural lesion detection, a sensitivity/specificity/ROC AUC of 95%/89%/0.92 and 93%/91%/0.91 were obtained in the test dataset for erosion and ankylosis detection, respectively. For patient-level lesion detection after pipeline optimisation for predefined statistical metrics, a sensitivity/specificity of 95%/85% and 82%/97% were obtained for erosion and ankylosis detection, respectively. Grad-CAM++ explainability analysis highlighted cortical edges as focus for pipeline decisions. CONCLUSIONS: An optimised deep learning pipeline, including an explainability analysis, detects structural lesions of sacroiliitis on pelvic CT scans with excellent statistical performance on a slice-by-slice and patient level. CLINICAL RELEVANCE STATEMENT: An optimised deep learning pipeline, including a robust explainability analysis, detects structural lesions of sacroiliitis on pelvic CT scans with excellent statistical metrics on a slice-by-slice and patient level. KEY POINTS: • Structural lesions of sacroiliitis can be detected automatically in pelvic CT scans. • Both automatic segmentation and disease detection yield excellent statistical outcome metrics. • The algorithm takes decisions based on cortical edges, rendering an explainable solution.

[Proximal femoral fracture with bony ankylosis of the hip joint : Case report of difficult surgical treatment]. / Proximale Femurfraktur bei knöcherner Ankylose des Hüftgelenks : Fallbericht einer erschwerten operativen Versorgung.

A 78-year-old female patient sustained a left-sided proximal femoral fracture due to a fall. Since childhood the patient had suffered from ankylosis of unknown origin in the ipsilateral hip joint. The recommended intramedullary osteosynthesis could restore the original status quo before the fracture. It needs less time in the operating room (OR) and includes a lower risk for intraoperative complications than a hip joint endoprosthesis. Arthroplasty can lead to a significant improvement in mobility of the hip joint but requires more time in the OR for the surgical procedure and anesthesia time and includes a higher risk for intraoperative and postoperative complications. The antetorsion angle of 76° in this patient deviated extremely from the standard and made the intramedullary osteosynthesis for this type of fracture a challenge. Using improvised techniques led to a load-stable fracture treatment that ultimately led to a satisfactory result.

Detecting hand joint ankylosis and subluxation in radiographic images using deep learning: A step in the development of an automatic radiographic scoring system for joint destruction.

We propose a wrist joint subluxation/ankylosis classification model for an automatic radiographic scoring system for X-ray images. In managing rheumatoid arthritis, the evaluation of joint destruction is important. The modified total Sharp score (mTSS), which is conventionally used to evaluate joint destruction of the hands and feet, should ideally be automated because the required time depends on the skill of the evaluator, and there is variability between evaluators. Since joint subluxation and ankylosis are given a large score in mTSS, we aimed to estimate subluxation and ankylosis using a deep neural network as a first step in developing an automatic radiographic scoring system for joint destruction. We randomly extracted 216 hand X-ray images from an electronic medical record system for the learning experiments. These images were acquired from patients who visited the rheumatology department of Keio University Hospital in 2015. Using our newly developed annotation tool, well-trained rheumatologists and radiologists labeled the mTSS to the wrist, metacarpal phalangeal joints, and proximal interphalangeal joints included in the images. We identified 21 X-ray images containing one or more subluxation joints and 42 X-ray images with ankylosis. To predict subluxation/ankylosis, we conducted five-fold cross-validation with deep neural network models: AlexNet, ResNet, DenseNet, and Vision Transformer. The best performance on wrist subluxation/ankylosis classification was as follows: accuracy, precision, recall, F1 value, and AUC were 0.97±0.01/0.89±0.04, 0.92±0.12/0.77±0.15, 0.77±0.16/0.71±0.13, 0.82±0.11/0.72±0.09, and 0.92±0.08/0.85±0.07, respectively. The classification model based on a deep neural network was trained with a relatively small dataset; however, it showed good accuracy. In conclusion, we provided data collection and model training schemes for mTSS prediction and showed an important contribution to building an automated scoring system.

Differences in morphology of temporomandibular joint ankylosis of traumatic and infective origin.

The aim of this study was to determine whether there are any differences in morphology between temporomandibular joint ankylosis (TMJA) of traumatic and infective origin. Cone beam computed tomography (CBCT) scans of 25 patients (28 joints) with TMJA of traumatic origin (trauma group) and 15 patients (15 joints) with TMJA of infectious origin (infection group) were included. The following morphological parameters were evaluated on multiple sections of the CBCT scans: lateral juxta-articular bone growth, residual condyle, residual glenoid fossa, ramus thickening, ankylotic mass fusion line, sclerosis of the ankylosed condyle and spongiosa of the glenoid fossa, and mastoid and glenoid fossa air cell obliteration. Lateral juxta-articular bone growth, juxta-articular extension of fusion, and the presence of normal medial residual condyle and residual glenoid fossa were exclusively found in post-traumatic TMJA. There were differences in ramus thickening (82.1% in trauma vs 53.3% in infection), sclerosis of the ankylosed condyle (100% in trauma vs 60% in infection), and sclerosis of the spongiosa of the glenoid fossa (100% in trauma vs 46.7% in infection) between the trauma and infection groups. Mastoid and glenoid fossa air cell obliteration was found more frequently in the infection group (mastoid obliteration: 23.1% in infection vs 4% in trauma; glenoid obliteration: 66.7% in infection vs 55.6% in trauma ). CBCT imaging can be helpful in differentiating between TMJA of traumatic and infectious origin.

Spontaneous ankylosis of the sacroiliac joint: prevalence and risk factors.

PURPOSE: Evidence on spontaneous sacroiliac joint (SIJ) ankylosis is lacking. The aim of this analysis was to assess the prevalence of spontaneous SIJ ankylosis and examined different ankylosis patterns and risk factors for spontaneous SIJ ankylosis. METHODS: Pelvic computed tomography (CT) data of 102 consecutive patients with spinal pathologies were compared to CT of a control group consisting of 102 consecutive patients without spinal pathologies. SIJ ankylosis patterns and risk factors for SIJ ankylosis, such as age, sex, and previous spinal fusion surgery were examined. RESULTS: Overall, 117 men and 86 women were examined between 2019 and 2020. Non-spinal patients were significantly older (mean age 70.5 years, standard deviation [SD] 11.4) than those in the spinal group (mean age 65.3 years, SD 14.3; p = 0.005). The prevalence of SIJ ankylosis was 24.5% in the non-spinal group and 23.5% in the spinal group. The anterior ankylosis type prevalence was 91.7% in the spinal group, compared to 48.0% in the non-spinal group. Factors associated with SIJ ankylosis were older age (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.01-1.07, p = 0.004) and male sex (OR 5.14, 95% CI 2.29-11.55, p < 0.001). CONCLUSION: Spontaneous ankylosis of the SIJ was a frequent phenomenon in patients with and without spinal pathologies and more likely with older age and male sex. Anterior type SIJ ankylosis was substantially more frequent in patients with spinal pathologies. This may be due to strain exerted on the anterior SIJ aspects in patients with compromised posture due to spine degeneration.

Puricelli biconvex arthroplasty as an alternative for temporomandibular joint reconstruction: description of the technique and long-term case report.

BACKGROUND: There are several indications for partial or total replacement of the temporomandibular joint (TMJ), including neoplasms and severe bone resorptions. In this regard, several techniques have been suggested to increase the functionality and longevity of these prosthetic devices. This case report describes the treatment of a TMJ ankylosis patient with the Puricelli biconvex arthroplasty (ABiP) technique, with a long-term follow-up. CASE PRESENTATION: In 1978, a 33-year-old male polytraumatised patient developed painful symptoms in the right preauricular region, associated with restricted movement of the ipsilateral TMJ. Due to subcondylar fracture, an elastic maxillomandibular immobilisation (EMMI) was applied. Subsequently, the patient was referred for treatment when limitations of the interincisal opening (10 mm) and the presence of spontaneous pain that increased on palpation were confirmed. Imaging exams confirmed the fracture, with anteromedial displacement and bony ankylosis of the joint. Exeresis of the compromised tissues and their replacement through ABiP was indicated. The method uses conservative access (i.e., preauricular incision), partial resection of the ankylosed mass, and tissue replacement using two poly(methyl methacrylate) components, with minimal and stable contact between the convex surfaces. At the end of the procedure, joint stability and dental occlusion were tested. The patient showed significant improvement at the postoperative 6-month follow-up, with no pain and increased mouth opening range (30 mm). At the 43-year follow-up, no joint noises, pain or movement restrictions were reported (mouth opening of 36 mm). Imaging exams did not indicate tissue degeneration and showed the integrity of prosthetic components. CONCLUSIONS: The present case report indicates that ABiP enables joint movements of the TMJ, allowing the remission of signs and symptoms over more than 40 years of follow-up. These data suggest that this technique is a simple and effective alternative when there is an indication for TMJ reconstruction in adult patients with ankylosis.

Heterotopic ossification after alloplastic temporomandibular joint replacement: a case cohort study.

BACKGROUND: Heterotopic ossification (HO) is one of the serious complications leading to the failure of alloplastic temporomandibular joint replacement (TJR). However, there was few research on its exact incidence and occurrence. Severe HO might result in pain and limited mouth opening after surgery. Therefore, it is necessary to clarify its clinical and imaging manifestations. The purpose of this study was to study the occurrence and classify HO after the alloplastic TJR. METHOD: Patients who underwent standard TJR (Zimmer Biomet stock prostheses or Chinese stock prostheses) with fat graft and at least 1-year-follow-up were included. HO was classified into 4 types according to postoperative computed tomography (CT) scans. Type and occurrence in different TMJ disease were compared. Joint space within 1 week after operation was measured and compared between HO and non-HO TJRs. Maximum incisal opening (MIO), pain, and quality of life (QoL) were recorded and their relevance with HO was analyzed statistically. RESULT: 81cases with 101 joints were included in the study. The mean follow-up time was 22.9 months (12 ~ 56 months). Among the 48 joints, 27 (56.3%) were type I (bone islands); 16 (33.3%) were type II (bone spurs from the mandibular ramus); 3 (6.3%) were type III (bone spurs from the fossa); and 2 (4.2%) were type IV (bone spurs from both the mandibular ramus and fossa). In HO patients, joint space in type IV was smaller than the other 3 types. Pain scores in HO were significantly greater than non-HO patients before and after operations (p < 0.05). 1 patient in Type IV HO developed ankylosis and had prosthesis revision which accounted for 2.1% in HO patients and 1.0% in all TJR patients. CONCLUSION: HO after alloplastic TJR with fat graft was not severe except for type IV, which was easy to cause ankylosis. Preserving sufficient TJR space was important for ankylosis prevention.

Treatment of Dentofacial Deformity Associated with Temporomandibular Joint Ankylosis Through Vertical and Sagittal Osteotomies of the Mandibular Ramus.

ABSTRACT: Ankylosis of the temporomandibular joint is a disorder resulting from fibrous, osseous, or fibro-osseous adhesion that directly affects the quality of life of the individual. The authors present a case of unilateral temporomandibular joint ankylosis treated by condilectomy and ipsilateral sliding vertical ramus osteotomy associated with contralateral sagittal osteotomy aiming to restore function and to correct dentofacial deformity class II. A 31-year-old female patient presented with a history of facial trauma and major complaint of oral opening limitation. Physical examination revealed hypoplasia of the lower third of the face, facial pattern type II, anterior open bite, and maximum mouth opening of 22.5 mm. Computed tomography showed an ankylotic mass in the right mandibular condyle with deformity of the condylar structure and fusion to the right zygomatic arch and a contralateral condylar fracture sequel. It was proposed to perform a condilectomy of the right mandibular condyle for the removal of the bone mass concomitant to the sliding vertical ramus osteotomy of the mandibular ramus for condylar reconstruction by rhytidectomy approach and the sagittal osteotomy of the left mandibular aiming the reestablishment of occlusion and the correction of dentofacial deformity. The condylar fracture was not operated because the condyle was remodeled. The patient is in her fourth year postoperative presenting satisfactory esthetic-functional re-stabilization, without clinical signs of recurrence. In conclusion, the authors believe that combined sliding vertical ramus osteotomy and sagittal osteotomy can bring satisfactory results in complex cases.

Silicone Implant Arthroplasty for Severe Bony Ankylosis of the Proximal Interphalangeal Joints in Rheumatoid Arthritis.

Arthrodesis and prosthetic arthroplasty have been used to treat severe proximal interphalangeal (PIP) joint arthritis. Silicone implant arthroplasty is an established treatment for rheumatoid arthritis (RA) of the fingers. However, few studies have reported the application of silicone implant arthroplasty for the treatment of severe ankylosis of the PIP joint in RA patients. The authors report, for the first time, the case of a 46-year-old woman who presented with severe bony ankylosis of the right fourth and fifth PIP joints at greater than 90° of flexion. Proximal interphalangeal silicone arthroplasty in combination with reconstruction of the extensor mechanism was successfully performed in the affected joints. Four years after surgery, active flexion of the fourth and fifth PIP joints was 55° and 75°, respectively, with an extensor lag of only 5° without pain and joint instability. Proper repair of the extensor mechanism with shortening of the central slips and mobilization of the lateral bands dorsally was most important in maintaining the extended position of the PIP joints. Proximal interphalangeal silicone arthroplasty with intensive reconstruction of the extensor mechanism could become a potential treatment option to maintain joint mobility even in severe ankylosis of the PIP joints in RA patients. [Orthopedics. 2022;45(1):e53-e56.].

Zygomaticocoronoid ankylosis with possible myositis ossificans: a very rare case.

Ankylosis forming between the zygomatic arch and the coronoid process is a rarely encountered pathological extracapsular ankylosis. Its treatment protocol consists of surgical removal of the coronoid process with the ankylotic mass and jaw opening-closing exercises after surgery. Myositis ossificans (MO) is a self-limiting, benign ossifying lesion. It affects all types of soft tissues including subcutaneous adipose tissue, muscles, tendons and nerves. It is most frequently found in the muscle as a solitary lesion. The clinical appearance of MO is generally in the form of a mass characterized with an ossified soft tissue. When it develops alone, cross-sectional imaging might not be specific, and it may appear similar to worse etiologies. It is suggested multiple imaging modalities should be used in the assessment of a suspicious soft tissue mass. MO is a benign self-limiting disease. In this case report, in the radiographic examination of a 41-year-old female patient, ankylosis between the left coronoid process and the zygomatic bone accompanied by possible MO in the left medial pterygoid muscle was observed. Resection of the coronoid process with the ipsilateral route, resection of the ankylotic mass with the hemicoronal approach and resection of the contralateral coronoid process with the intraoral approach were performed, but the ossified formation in the medial pterygoid muscle was not touched.

Extraarticular joint ankylosis: a rare presentation.

Pseudoankylosis is a rare condition that causes inability to open the mouth due to condition related to outside of the temporomandibular joint. Most literature refers to this hypomobility disorder, a result of fusion of the zygomatic bone to the coronoid process, and very rarely is insidious coronoid hyperplasia causing mechanical interference with the posterior maxilla has been reported. We present a case of a 45-year-old woman, who presented with coronoid malformation and overgrowth resulting in progressive decrease in mouth opening. She was managed with coronoidectomy, following which good mouth opening was obtained. In this paper we discuss about the diagnosis and management of this rare disorder.

Mandibular osteoma as a cause of ankylosis and progressive trismus.

Osteomas are benign tumours of bone tissue restricted to the craniofacial skeleton. The aim of this article is to present and discuss the demographic and clinical aspects and the management of craniomaxillofacial osteomas. When the patient was submitted from primary care to our hospital, he was 68 years old, and he had ankylosis of the temporomandibular joint for the previos 4 years. A CT scan was performed, finding a giant mandibular osteoma. Conservative treatment and radiological follow-up were carried out with clinical stability. Osteomas more often are seen in the paranasal sinuses and in young adults, with no differences in gender. Most are asymptomatic, but they can cause local problems. For its diagnosis, CT is usually performed. Treatment options are conservative management and follow-up or surgery. Although rarely, they can recur. Mandibular peripheral osteoma is a rare entity. Depending on the symptoms, a conservative or surgical treatment can be chosen. A clinical and radiological follow-up is necessary to detect possible recurrences or enlargement.

Surgical navigation system for temporomandibular joint ankylosis in a child: a case report.

BACKGROUND: Computer-assisted surgical navigation systems were initially introduced for use in neurosurgery and have been applied in craniomaxillofacial surgery for 20 years. The anatomy of the oral and maxillofacial region is relatively complicated and includes critical contiguous organs. A surgical navigation system makes it possible to achieve real-time positioning during surgery and to transfer the preoperative design to the actual operation. Temporomandibular joint ankylosis limits the mouth opening, deforms the face, and causes an increase in dental caries. Although early surgical treatment is recommended, there is controversy regarding the optimal surgical technique. In addition, pediatric treatment is difficult because in children the skull is not as wide as it is in adults. There are few reports of pediatric temporomandibular joint ankylosis surgery performed with a navigation system. CASE PRESENTATION: A 7-year-old Japanese girl presented severe restriction of the opening and lateral movement of her mouth due to a temporomandibular joint bruise experienced 2 years earlier. Computed tomography and magnetic resonance imaging demonstrated left condyle deformation, disappearance of the joint cavity, and a 0.7-mm skull width. We diagnosed left temporomandibular joint ankylosis and performed a temporomandibular joint ankylosis arthroplasty using a surgical navigation system in order to avoid damage to the patient's brain. A preauricular incision was applied, and interpositional gap arthroplasty with temporal muscle was performed. After the surgery, the maximum aperture was 38 mm, and the limitation of the lateral movement was eliminated. CONCLUSIONS: A navigation system is helpful for confirming the exact target locations and ensuring safe surgery. In our patient's case, pediatric temporomandibular joint ankylosis surgery was performed using a navigation system without complications.

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 3mm lateral bone reduction for fossa placement. The ramal length were categorised into ranges 35-40mm (n=15), 41-45mm (n=14), 46-50mm (n=28) and >50mm (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 (45mm) 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.

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.

Does Bilateral Gap Arthroplasty Increase the Severity of Obstructive Sleep Apnea in Patients With Temporomandibular Joint Ankylosis?

PURPOSE: Obstructive sleep apnea (OSA) is common in patients with bilateral temporomandibular joint ankylosis (TMJA). The purpose of this study was to compare the preoperative and postoperative apnea-hypopnea index (AHI) in patients with TMJA undergoing bilateral gap arthroplasty (BGA). METHODS: The investigators implemented a prospective cohort study on patients with bilateral TMJA treated with BGA. The primary predictor variable was time (before and after BGA). The primary outcome variable was AHI and secondary outcome variable included posterior airway space, skeletal changes, Epworth sleepiness scale, minimum oxygen, average oxygen saturation, and maximal incisal opening at preoperative time (T0), 1 month (T1), and at 6 months (T2). The statistical test used were Greenhouse-Geisser test, repeated measure ANOVA (1 way), followed by post hoc Bonferroni test. The P-value was taken significant when <0.05 at a confidence interval of 95%. RESULTS: The study sample included 12 (m:f = 1:2) patients of bilateral TMJA with a mean age of 14.9 ± 4.8 years and mean follow-up of 6 months. Mean duration of ankylosis was 10.5 ± 6.9 years (median = 12). Trauma was the main etiological factor in 11 (91.7%) patients followed by infection in 1 (8.3%) patient. The mean increase in AHI was 8.6 (T0 to T1) with P-value = .002 and 23.4 (T1 to T2) and was statistically significant (P = .001). The mean decrease in posterior airway space was 4.5 ± 1.0 to 3.5 ± 0.5 (T0 to T2) and was statistically significant (P = .02). Mean difference in minimum oxygen was 6.8 (P-value = .015). Skeletal changes are consistent with clockwise rotation of the mandible and statistically significant changes in horizontal and vertical dimension. The mean change in average oxygen was statistically insignificant (P = 1.0). CONCLUSIONS: The present study concludes that gap arthroplasty in patients with bilateral TMJA can lead to development or worsening of pre-existing mild to moderate OSA. Ramus-condyle reconstruction should be performed to prevent the retropositioning of mandible and worsening of OSA.