Classifications And Treatments Of Traumatic Temporomandibular Joint Ankylosis

Part 1:A newly proposed classification on traumatic temporomandibular joint ankylosis:a retrospective analysis of 71 patients.Purpose:A new classification of traumatic temporomandibular joint(TMJ)ankylosis was proposed based on computed tomography(CT).This study aimed to describe the clinical features of different types of traumatic TMJ ankylosis.Methods:From January 2012 to December 2015,71 patients(94 sides)were divided into four types:type Ⅰ was non-bony ankylosis of the joint;type Ⅱ was lateral bony ankylosis;type Ⅲa was complete bony ankylosis of the whole joint;and type Ⅲb was extensive bony ankylosis.The following parameters were analyzed in corresponding to each type:disease course,maximal mouth opening(MMO),complications and histopathological changes.Our treatment protocol for typeⅠ ankylosis was fibrous tissue release and articular disc reduction.For typeⅡ ankylosis was condyle-preserved arthroplasty.For type Ⅲa and Ⅲb ankylosis was gap arthroplasty combining condylar reconstruction.The result of the treatment was evaluated by CT scan and clinical follow-up.Results:It was found that 11 patients were type Ⅰ;21 patients were type Ⅱ;25 patients were type Ⅲa;14 patients were type Ⅲb.The reliability analysis showed good internal consistency(Kappa=0.922).A negative correlation was found between types and age at time of maxillofacial trauma(r=-0.644),and also between types and MMO(r=-0.489).In contrast,a positive correlation was found between types and time after maxillofacial trauma(r=0.733).There was a significant difference in the incidence of complications among the different types(p<0.05).Pathological features of different types varied significantly.All surgical methods were effective for treatment of temporomandibular joint ankylosis.Conclusion:These results suggested that the classification efficiently evaluate the severity of clinical manifestation and reflect histological changes.Younger trauma patients with long post-trauma periods tended to develop more severe TMJ ankylosis,experience more complications,and face more challenges in treatment than older patients.Part 2:Observation on the mandibular growth of children with different types of temporomandibular joint ankylosis after condyle-preserved arthroplasty or costochondral graftingPurpose:To evaluate results of different types of temporomandibular joint ankylosis in growing children after condyle-preserved arthroplasty or costochondral grafting through follow up and three-dimensional metric analysisMethods:We assessed 11 patients(14 sides)with type Ⅱ ankylosis and 11 patients(13 sides)with type Ⅲ ankylosis from January 2012 to December 2015.Type Ⅱ patients received condyle-preserved arthroplasty and Type Ⅲ patients received costochondral grafting.Changes in maximum mouth opening were evaluated after surgery.Postoperative computed tomography was used to measure condylar height,condylar width,mandibular ramus height,and mandibular body length.Results:Postoperative follow-up showed similar average maximum mouth opening and one case of recurrence in each group.Computed tomography measurements showed that condylar width and mandibular ramus height increased in both Type Ⅱ and Type Ⅲ(P<0.05).Moreover,in Type Ⅱ patients,condylar angulation of medially displaced malformation decreased significantly(P<0.05),and mandibular body length increased significantly(P<0.05).Conclusion:Both condyle-preserved arthroplasty and costochondral grafting were effective surgical methods for treatment of temporomandibular joint ankylosis.Moreover,compared with Type Ⅲ,Type Ⅱ patients manifested more remarkable mandibular growth,at least in the anteroposterior direction of the mandibular body.Part 3:Evaluating the remodeling of condyles reconstructed by transport distraction osteogenesis in the treatment of temporomandibular joint ankylosisPurpose:We aimed to evaluate the remodeling of condyles reconstructed by transport distraction osteogenesis(DO)in patients with temporomandibular joint(TMJ)ankylosis.Methods:21 patients(26 sides)had undergone gap arthroplasty and TMJ reconstruction by DO were included.Maximal mouth opening(MMO)and occlusion were recorded.Computed tomography images were obtained preoperatively(TO),upon completing distraction(T1),upon removal of the distraction device(T2),and follow-up time(T3).The following were measured:mandibular ramus height,distance between gonion and Frankfurt plane(Go-FN),condylarwidth,and condyle-ramus angulation.Results:Of the 21 patients,one showed re-ankylosis,while 5 exhibited anterior open bite.From T1 to T3,the total amount of resorption in ramus height reached up to 8.2 mm(P<0.05)in comparison to the total distraction length of 13.8mm;the mean resorption rate was 59.4%.Similarly,Go-FN decreased by 6.2mm(P<0.05).Conclusion:Our findings indicate that DO combine with gap arthroplasty is an effective method for the treatment of TMJ ankylosis to improve MMO.The reconstructed condyle exhibited a high frequency of resorption in height.Part 4:Application of medial femoral condyle osseocartilaginous flap in the treatment for temporomandibular joint ankylosis:a prospective studyPurpose:To present the preliminary results of the application of medial femoral condyle(MFC)osseocartilaginous flap in the treatment for temporomandibular joint ankylosis.Methods:5 patients(5 sides)with typeⅢ ankylosis from May 2019 to September 2020 were included.The MFC osseocartilaginous flap was used as a free vascularized graft for the treatment of TMJ ankylosis and condylar reconstuction.A computer-assisted technique was used in all cases.Postoperative computed tomography was used to measure the mandibular ramus height and condylar width.Complications were recorded during follow-up visits.Facial symmetry was self-evaluated by patients.Lower extremity functional status was assessed by the Lower extremity functional scale(LEFC)questionnaire.Results:The MFC osseocartilaginous flap success rate was 100%in all five patients and normal occlusion was achieved after surgery.No flap-related complications occurred.No difference was found in the mandibular ramus height and condylar width during follow-up.All patients were satisfied with postoperative facial symmetry and oral function.The LEFC score ranged from 73 to 80,indicating normal lower extremity function.Conclusion:Vascularized MFC osseocartilaginous flap appears to be a reliable option for the treatment for temporomandibular joint ankylosis.