Temporomandibular Joint Arthroplasty Research Articles

Clinical negligence in temporomandibular joint surgery

This study reviewed the medical reports of 25 patients (21 female and 4 male) who were found to have been treated inappropriately by temporomandibular joint (TMJ) surgery. One of more Breaches of Duty and resultant harms (Causation) were identified for each of the patients in this series. Their ages ranged from 18–64 (mean 36.2, median 35) years. A narrative review of free text data revealed six main patterns of Breach of Duty which were to do with consent, inadequate pre-surgical imaging, injection of botulinum toxin into jaw muscles, TMJ arthroplasty, management of TMJ dislocation and subluxation, and failure or reluctance to request second opinions. Harms identified included surgical damage to the TMJ, facial nerve dysfunction, and social isolation. One sum claimed was in excess of £1 million.

Are Outcomes of Temporomandibular Joint Arthroscopy Influenced by Central Sensitization?

A proportion of subjects with internal derangements of the temporomandibular joint (TMJ) may have a central sensitization disorder that may affect pain perception after surgery. This study aims to estimate the association between fibromyalgianess (FMness) score, a summed score of the Widespread Pain Index (WPI) and Symptom Severity Sore (SSS), and outcomes following TMJ arthroscopy. A retrospective cohort study including individuals who received arthroscopy for TMJ internal derangement at Michigan Medicine between 2011 and 2020 was performed. A predictor variable, FMness score, was assigned via the sum of WPI and SSS. Univariate and bivariate analyses were performed. Linear-mixed effects models were used to analyze 6 different outcomes, each in their own model: pain, jaw functional limitation scale (JFLS), JFLS-mobility domain, pain-related disability, comfortable maximum interincisal opening, and active maximum interincisal opening. Covariance structure was selected based on null model fit separately for each outcome. Thirty-one subjects were included in the study sample. Twenty-eight subjects were female. Average age was 45.9years. Bivariate analysis demonstrated that subject's FMness score was not correlated with pain (b=0.03 [-0.10, 0.17] P=.59) or JFLS score (b=1.00 [-.80, 2.81] P=.27). However, subject's FMness score was significant for predicting JFLS-mobility domain score (b=.61, [0.05, 1.18] P=.04). A greater extent of central sensitization was associated with lower comfortable mouth opening after surgery, greater limitations in opening wide enough to eat various foods (higher JFLS-mobility scores), and higher pain-related disability. Future studies with larger sample sizes and reconstructive TMJ operations such as total TMJ arthroplasty may help clarify the impact of SSS and WPI scores on outcomes of TMJ surgery.

Clinical evaluation of growth potentiality of autogenous costochondral graft in Temporomandibular joint on New Zealand white rabbit- an experimental study

Background: Costochondral graft has been used as a substitute for a growth center in the damaged Temporomandibular joint (TMJ) in the growing children. But the relapse of the TMJ ankylosis along with facial deformity is the most common outcome after the surgery for the resorption or overgrowth of the graft. While an exploration of the human Temporomandibular joint seems to be unethical after reconstruction with an autogenous costochondral graft for study purposes, therefore we sought to determine the growth potential of the graft by clinical evaluation. Material and methods: An experimental study was done on 96 New Zealand white male rabbits, which were divided into batches. Each batch (total 2 batches) contained 24 experimental and 24 control rabbits of known ages and species; growing (3-4) and adult (12-18) months old. TMJ arthroplasty with a costochondral graft using either 1mm or 4 mm thickness of cartilaginous cap done in both age groups. Follow-up was done regularly in batches comparing with control up to 4th, 12th, and 24th weeks of surgery to find out any relationship of behavioral change, clinical presentation, and macroscopic growth of the graft. Results: There was a relationship among the rabbits with their behavioral change, clinical presentation, and presence of growth center in the graft. Growth was found in 60% cases, 40% was growing, and 20% in adults. Conclusions: Costochondral graft had a 60% growth potentiality. The failure rate of 40% may be due to some unknown factors. Grafts grew in a greater number of growing rabbits than adults. Long time follow-up had a strong role in the growth of the graft. In conclusion, clinical evaluation of the rabbit model provided a fair estimation of the growth process.

Management of cardiorespiratory function of rabbits by a customized chest drain: An experimental study.

Objective:This study aimed to salvage the study population from the fatality that occurs due to iatrogenic injury to the thoracic cavity’s pleural membrane.Materials and Methods:An experimental study of temporomandibular joint arthroplasty with costochondral graft was carried out on 72 healthy ‘Oryctolagus cuniculus’ species of male rabbits. The rabbits were distributed into two age groups: growing (3–4 months) and adult (12–18 months). All the procedures were carried out under general anesthesia with xylazine hydrochloride and ketamine hydrochloride after calculating the doses, maintained by halothane and O2 inhalations. Out of 72 rabbits, 33 rabbits had accidental perforation of the pleural membrane observed that required a chest drain.Results:In this study, 21 (63.64%) rabbits received chest drain and salvaged. The rest of the rabbits (n = 12; 36.36%) that did not receive any chest drain and died. Most of the rabbits (n = 17; 81%) were under the growing group, weighing less than 2 kg and four (19%) were adult rabbits.Conclusion:This manual chest drain is life-saving for rabbits. It is a new addition to the advancement of thoracic surgery on animals. It is cost-effective and safe. The developed customized drainage system may make it easier to harvest the costochondral graft-related experiments.

Treatment of extensive tumors of the jaws by hemimandibuloectomy with simultaniouse reconstruction of the mandible, arthroplasty of temporomandibular joint, orthopedic rehabilitation supported by dental implants

Background. Reconstruction of subtotal and total defects of maxillofacial region after ablative tumor surgery is a challenging task of reconstructive surgery. The “golden rule” is maintaining of radicalism of ablative surgery as well as appropriate surgical reconstruction and prosthodontic rehabilitation, that allows patient return to normal life. Wherein reconstructive procedure is focusing on restoring of mandibular continuity by the means of different flaps and grafts, while prosthodontic rehabilitation is performing after some period of time (usually around year) by the means of removable and non-removable prosthodontic devices. Non-removable device requiring dental implants insertion into grafted material followed by period of osteointegration, that is requiring some time as well. However, within this period of time one could observe significant soft tissue deformity.The objective is to improve the outcomes of surgical reconstruction of extensive defects of the mandible and to carry out rapid prosthodontic rehabilitation supported by dental implants by application of 3D preoperative planning and navigation devices.Clinical case. Forty-nine years-old female patient with recurrent ameloblastoma, that affects vertical and horizontal ramus of the mandible. Within virtual preoperative planning one performed: resection of the mandible associated with exarticulation of condylar head, virtual plate bending according to contours of the mandible (that were determined by application of “mirror” function of virtual planning software), arthroplasty of temporomandibular joint, determination of donor site on fibula bone, osteotomy of fibula free flap, positioning of dental implants, transferring of composite flap and it’s fixation by reconstructive plate. According to acquiring data one performed fabrication of patient specific navigation guides for both fibula flap segmentation and dental implants positioning. Surgical procedure included single-step tumor ablation and exarticulation of condylar head, reconstruction of defect by the means of osseo-myo-cutaneous fibula free flap, that was pre-implanted by dental implants, total joint reconstruction by titanium condylar head and polypropylene fossa, fixation of the flap and condylar head in recipient site by the means of prebended reconstructive plate, as well as insertion of non-removable bridge prosthodontic device. Postoperative result was asses clinically and radiologically. No significant postoperative complications occurred. Restoration of facial contours, mouth opening, I class occlusion, as well as adequate meal and speech were detected. Postoperative radiological investigation revealed adequate positioning of dental implants within neo-mandible, as well as positioning of artificial joint.Conclusion. In cases of extensive tumors of the jaws single-step ablative surgical procedure, reconstruction of missing anatomical structures of the jaws and simultaneous prosthodontic rehabilitation allows to prevent possible deformities of the soft tissues and due to rapid restoration of vital functions has great impact to quality of patient’s life. Adequacy of performing procedures could be reached by implementation of virtual preoperative planning and fabrication of patient-specific surgical guides.

Does Repositioning of Temporomandibular Joint Disc With Bone Anchors Provide Better Clinical Outcomes Than Conventional Disc Plication Procedures for Anterior Disc Displacements Without Reduction in Patients Refractory to Nonsurgical Treatments?

Although open temporomandibular joint arthroplasty with discopexy is a common treatment for patients with anterior disc displacements without reduction (ADDWo) unresponsive to medical management, there are no studies comparing disc repositioning with bone anchors and conventional discopexy procedure. The purpose of the study was to compare the efficacy between disc repositioning with bone anchors and the conventional discopexy procedure for ADDWo of temporomandibular joint refractory to medical management. A randomized controlled trial was conducted in patients with ADDWo. The primary objective was to compare the improvement in mouth opening (primary outcome variable) between the 2 treatment (primary predictor variable) groups-disc repositioning with bone anchors versus conventional disc plication. Secondary outcome variables were pain measured by visual analog scale, lateral excursions, and position of the disc evaluated by magnetic resonance imaging (MRI). Other variables of interest were age, gender, and duration of symptoms. The parameters were evaluated at preoperative, postoperative day 1, and 1-, 6-, and 12-month postoperative period. Categorical variables were compared with χ2 test and continuous variables with analysis of variance and adjusted for multiple comparisons with Bonferroni test. The study sample comprised 14 patients (7 in each group) with MRI-proven ADDWo. Statistically significant differences were found in the improvement of mouth opening between the 2 groups, showing better improvement with bone anchors (14.42±5.96 vs 7.57±7.25mm; P<.05). The reduction in visual analog scale also showed statistically significant difference with better pain reduction achieved with bone anchor (4.57±1.61 vs 3.28±0.75; P<.05). There was no statistically significant difference in lateral excursions and postoperative position of the disc evaluated by MRI between the groups at the 12-month follow-up period. Disc repositioning with bone anchors provides better clinical outcomes in terms of maximal mouth opening and pain scores compared with conventional disc plication.

Intraoperative Three-dimensional Virtual Reality and Computed Tomographic Guidance in Temporomandibular Joint Arthroplasty of Syndromic Craniofacial Dysostoses

Bony ankylosis of the temporomandibular joints (TMJ) occurs in up to 28% of patients with syndromic mandibular dysostoses. Release of complete osseous ankylosis is particularly challenging due to the lack of tissue planes separating the mandible from the skull base and the presence of congenital skeletal abnormalities. One recent advance in surgical imaging technology is three-dimensional virtual reality (3D VR), now in common use in neurosurgical resections. In this study, we describe the usage of 3D VR in TMJ arthroplasty and compare 3D VR to traditional computed tomographic (CT) guidance. Pediatric patients with syndromic mandibular micrognathia including Treacher Collins, Nager, and cerebrocostomandibular syndrome were retrospectively evaluated between 2008 and 2016. Patient characteristics, complications, inpatient times, and operative times were recorded. Of the 29 children with syndromic mandibular micrognathia treated between 2008 and 2016, 7 were diagnosed with TMJ ankyloses. Four consecutive pediatric patients (mean 8.7 years) undergoing interpositional TMJ arthroplasty with Matthews device placement were retrospectively evaluated. Two patients underwent traditional CT-guided versus 3D VR-guided temporomandibular joint arthroplasty (TMJA). No statistically significant differences were found among the age, complications, or inpatient hospitalization times. The average operative time in the traditional CT guidance group was 300 minute versus 134 minutes in the 3D VR group. Three-dimensional VR is a useful preoperative planning and intraoperative guidance tool. The major difference between VR and older technologies is the improved imaging in 3 dimensions for guidance, thereby potentially decreasing operative times.

Revision temporomandibular joint arthroplasty for the treatment of acquired metal allergy and review of the literature

The purpose of this study was to examine the outcomes of patients who received revision temporomandibular joint (TMJ) arthroplasty for the treatment of acquired metal allergy. It was hypothesized that subjects would have significant improvements in pain, swelling, and function. Patients who underwent TMJ revision due to nickel allergy were identified retrospectively. Outcomes documented included the presence or absence of facial erythema and facial swelling. Maximum incisal opening was also measured. Additional outcomes collected included age at initial surgery, initial TMJ device type, presenting symptoms, and TMJ device used for surgical revision. Four patients were identified with a nickel allergy to their TMJ prosthesis (containing nickel). All subjects experienced pain and swelling as their primary symptoms prior to the revision, with two subjects showing dermatological symptoms of overlying erythema. The four female subjects underwent exchange of their previously implanted prosthesis with a titanium alloy prosthesis. Postoperatively, all subjects showed improvements in pain score, resolution of swelling and erythema, and improvements in maximum incisal opening. This small case series suggests that revision TMJ arthroplasty with a titanium alloy prosthesis is a potential treatment for acquired metal allergy from traditional TMJ prosthesis implantation.

Temporomandibular joint arthroplasty for osteoarthrosis: A series of 24 patients that received a uni- or bilateral inter-positional silicone sheet

PurposeTo evaluate mid-term results from using a silicone sheet for inter-positional arthroplasty in moderate or severe cases of osteoarthrosis of the temporo-mandibular joint (TMJ). To also determine any remaining indications from this method. Patients and methodsThis retrospective study included patients that underwent surgery between 2008 and 2016. Pre- and post-operative mouth opening (MO), according to inter-incisal distance (mm) and pain score (PS: 0=no pain to 4=very severe pain) were recorded for 24 patients. Patients were divided according to thickness of the silicone sheet (group A: 1.0 mm, group B: 1.5 mm). ResultsThe cohort included 22 females (92%). Mean age at surgery was 55 years±13 (26–80). Mean length of follow-up was 26 months±24 (6–80). Mean improvement in MO was 8.2 mm (+33%) and of PS was 1.7 (−68%). MO was not improved for two patients and worsened for one. PS score improved for all patients. No statistical difference was found between groups A and B. There was also a tendency for degradation of outcomes over time. ConclusionThe poor reputation of prosthetic discoplasty was not as evident in our series, even though anatomical and functional status seemed to deteriorate over time. This is because total-joint prosthetic replacement is often proposed instead. However, for elderly or fragile patients that have severe pain, and regarding cost-benefit aspects, conventional arthroplasty can still be discussed, especially since French national health-care insurance does not yet support TMJ prosthetic replacement for osteoarthrosis.

Lateral Arthroplasty as an Optimal Treatment for Surgical Management of Unilateral Temporomandibular Joint Ankylosis Type III in Children

Management of temporomandibular joint (TMJ) ankylosis described in the literature showed many surgical techniques. Purpose: The aim of this study was to evaluate the lateral TMJ arthroplasty as a surgical technique for treatment of type III Sawhney’s TMJ ankylosis in children both clinically and radiographically. In that surgical technique the need of a costochondral graft for reconstructive arthroplasty is avoided with its potential complications (as a donor site) and the unpredictable growth pattern. Materials & Methods: Eight children with unilateral type III Sawheny ankylosis (ankylosis on the lateral aspect of the medially displaced condyle) were included in this research. They all underwent lateral TMJ arthroplasty with the aid of panoramic and coronal C.T views. Evaluation was done both clinically and radiographically regarding interincisal distance, lateral TMJ movement, protrusive movements, postoperative pain, patient’s satisfaction and hazards of facial nerve injury. All patients were seen weekly for 4 weeks, at three and six months then at one year. Results: The used surgical technique of lateral arthroplasty had greatly achieved the desired goals of treating TMJ ankylosis during a follow up period of one year. Those achieved goals include restoration of full mandibular function and free movements of the joint with adequate mouth opening and a mean interincisal distance of 35 mm, maintaining acceptable occlusion and ramus height and obviates the need of any autogenous chondro-osseous graft (commonly costochondral) with potential complications of the donor sites. Conclusion: The surgical procedure of lateral arthroplasty is an easy and safe technique. It is considered as an effective treatment modality in treatment of type III TMJ ankylosis especially in children.

Temporomandibular Joint Discectomy With Abdominal Fat Graft Versus Temporalis Myofascial Flap: A Comparative Study

Open temporomandibular joint (TMJ) arthroplasty with discectomy has been described as a primary surgical treatment and as a secondary treatment when minimally invasive procedures have failed. The aim of the present study was to compare TMJ discectomy with a fat graft versus TMJ discectomy with a temporalis graft using the pain score and maximal interincisal opening (MIO). We performed a retrospective study of patients who had undergone TMJ arthroplasty and discectomy with an abdominal fat graft or an interpositional temporalis flap at the University of Michigan from 1999 to 2014. The predictor variable was the type of surgical intervention. The main outcome variables were the pain score and MIO. Additional outcome variables were diet, medication use, the presence of myofascial pain, and occlusal outcomes. The statistical analysis included the mean ± standard deviation, a 1-way analysis of variance for continuous data, and Pearson's χ2 test for categorical variables. The study cohort included 50 patients, of whom 30 had undergone discectomy with a fat graft and 20 had undergone discectomy with a temporalis myofascial graft. The mean pain scores were decreased by 78.3% in the myofascial flap group and 52.8% in the fat graft group. Changes in MIO showed a statistically significant increase in the fat graft group but only approached statistical significance in the myofascial flap group. The patients who had undergone TMJ arthroplasty and discectomy with a temporalis myofascial flap showed significantly greater improvement in pain scores and marginal improvement in the MIO compared with patients who had received an abdominal fat graft.

Modified T-Plate Interpositional Arthroplasty for Temporomandibular Joint Ankylosis: A New and Versatile Option.

BackgroundThis study has been conducted with the aim of evaluating modified T-plate interpositional arthroplasty.MethodsA prospective comparative study in patients admitted with temporomandibular joint ankylosis. Ankylotic temporomandibular joint arthroplasty included condylectomy gap arthroplasty in 7, temporalis muscle flap interpositional arthroplasty in 8, and modified T-plate interpositional arthroplasty in 13 cases. The patients were followed for three years. Collected data were tabulated and subjected to Fisher's exact test, chi-square test and probability estimation.ResultsA significant increase in interincisal distance of 32 mm was seen in 12 (92.31%) patients in the T-plate interposition group, in 2 (25%) cases of the temporalis muscle flap interposition group, and in 1 case (14.28%) of the condylectomy group at 12, 24, and 36 months. Re-ankylosis was observed in 1 case (9.69%) of the T-plate interposition group, while as it was observed in 4 (50%) cases in the temporalis muscle flap interposition group and 4 (57.14%) cases in the condylectomy group, and these differences were statistically significant.ConclusionsOur clinical experience with the use of the T-plate over the past 5 years has been encouraging, and our physiotherapy technique is quite simple. Even illiterate parents can assess it easily. Hence, we recommend this easy technique that does not damage the temporalis muscle for the management of temporomandibular joint ankylosis.

Retrospective study of facial nerve function following temporomandibular joint arthroplasty using the endaural approach.

The aim of this retrospective case-control study is to evaluate the incidence of facial nerve injury associated with temporomandibular joint (TMJ) arthroplasty using the endaural approach for the treatment of TMJ pathology. The sample consisted of 36 consecutive patients who underwent TMJ arthroplasty. A total of 39 approaches were performed through an endaural incision. Patients undergoing total joint replacement and/or with preexisting facial nerve dysfunction were excluded from the study. Five patients were lost to follow-up and were excluded from the study. Facial nerve function of all patients was clinically evaluated by resident physicians preoperatively, postoperatively, and at follow-up appointments. Facial nerve injury was determined to have occurred if the patient was unable to raise the eyebrow or wrinkle the forehead (temporalis branch), completely close the eyelids (zygomatic branch), or frown (marginal mandibular branch). Twenty-one of the 36 patients or 22 of the 39 approaches showed signs of facial nerve dysfunction following TMJ arthroplasty. This included 12 of the 21 patients who had undergone previous TMJ surgery. The most common facial nerve branch injured was the temporal branch, which was dysfunctional in all patients either as the only branch injured or in combination with other branches. By the 18th postoperative month, normal function had returned in 19 of the 22 TMJ approaches. Three of the 22 TMJ approaches resulted in persistent signs of facial nerve weakness 6 months after the surgery. This epidemiological study revealed a low incidence of permanent facial nerve dysfunction. A high incidence of temporary facial nerve dysfunction was seen with TMJ arthroplasty using the endaural approach. Current literature reveals that the incidence of facial nerve injury associated with open TMJ surgery ranges from 12.5 to 32%. The temporal branch of the facial nerve was most commonly affected, followed by 4 of the 22 approaches with temporary zygomatic branch weakness. Having undergone previous TMJ surgery did not increase the incidence of facial nerve injury using the endaural approach. This information is important for patients and surgeons in the postoperative period, as a majority of patients will experience recovery of nerve function.

Modified condylar distraction osteogenesis via single preauricular incision for treatment of temporomandibular joint ankylosis.

Temporomandibular joint (TMJ) ankylosis with facial asymmetry is still controversial to deal with. This study describes a modified condylar distraction osteogenesis protocol via preauricular approach for the treatment of this condition. From 2006 to 2013, 18 patients with TMJ ankylosis were enrolled. The Wuhan TMJ Ankylosis treatment protocol includes as follows: (1) preauricular approach is the only surgical access; (2) TMJ arthroplasty is used to recontour the condylar head, and the vertical height of condyle is maintained; (3) distractor placement with distractor port exiting via preauricular incision; (4) distraction after 5 to 7 days of latency period with 0.5 mm twice daily; and (5) distractor removal after 3-month consolidation through preauricular incision. All patients had clinical follow-up and detailed examination. All patients had satisfactory results postoperatively. The mean (range) mouth opening increased from 7.1 (0-18) to 32.1 (28-43) mm during 37 (6-81) months of follow-up period (P < 0.01). Facial asymmetry was corrected in all patients, and all patients had minimal postoperative scar perception of the preauricular incision. The Wuhan TMJ ankylosis protocol provides a safe and effective treatment alternative in managing TMJ ankylosis, especially in young women who are anxious about perceptive extraoral scar.

Anteriorly Pedicled Wide Temporalis Muscle Flap With the Minimum Zygomatic Osteotomy Technique for Post-Discectomy Temporomandibular Joint Arthroplasty

An anteriorly pedicled temporalis muscle flap has been shown to be a suitable interpositional material for the treatment of ankylosis and post-discectomy arthroplasty. The passage of the wide flap beneath the zygomatic arch into the joint space can be difficult owing to its bulk, causing excessive trauma to the vascularized pedicle. We describe the use of minimum zygomatic osteotomy without fixation for the passage of an anteriorly pedicled wide temporalis muscle flap for post-discectomy arthroplasty.

Functional TMJ arthroplasty: 30 years experience

TMD (temporomandibular joint disorder) is a collective term used to describe a number of related disorders affecting the temporo-mandibular joint (TMJ), masticatory muscles and associated structures, all of which have common symptoms such as pain and limited mouth opening. In the present study the authors perform a retrospective analysis of all patients affected by internal derangement, according to Wilkes’ criteria, who underwent surgery of condilar shaving and disc reposition. From 1982 to 2005, at the Department of Maxillo-Facial Surgery, ‘Sapienza’ Università di Roma, 352 patients were treated throughout open joint surgery for a total number of 696 treated joints. Long term follow up was accomplished in every patient from the smallest value of 3 years to the highest of 26 with a mean value of 12.5 years. A post surgical evaluation of the local pain was performed according to same classes of pre-surgical evaluation supplying the following results: in 543 joints there was no local pain corresponding to class I (78%), in 70 joints a class II pain range was present (10%), in 42 joints a class III was reported (6%), 28 joints presented a class IV (4%) and 13 joints class V (2%). Post surgical headache and cervical pain varied significantly: Class I counted 190 patients (54%), class II counted 77 patients 22%, class III counted 39 patients (11%), class IV counted 21 patients (6%) and class V counted 25 patients being the 7% of the whole sample. Maximum wide opening has been evaluated both before and after surgery. Surgical treatment in our opinion should be a consistent part of the therapeutic protocol. Our protocol aims for the most part to the restoration of morphofunctional recovery. The results we had widely confirm the viability of our surgical approach for internal derangement.

Retrospective Study of Facial Nerve Function Following Temporomandibular Joint Arthroplasty Using the Endaural Approach

Retrospective Study of Facial Nerve Function Following Temporomandibular Joint Arthroplasty Using the Endaural Approach

Biomet Microfixation TMJ Replacement System: A 3-Year Follow-Up Study of Patients Treated From 1995 to 2005

Giannakopoulos et al have reported their results after total temporomandibular joint (TMJ) arthroplasty with the Biomet Microfixation TMJ Replacement System in a diagnostically diverse group of 288 patients. They have reported statistically significant improvements in pain, interference with eating, and vertical opening 3 years after joint replacement. Given the controversy and criticism surrounding TMJ replacement, by showing the biomechanical integrity of 1 of a limited number of total joint systems, this report is a valuable contribution to the literature on total TMJ arthroplasty systems.

Correction of Rabbit Model With Mandibular Ramus Shortening by Distraction Osteogenesis at Condylar Neck

The rabbit model has been established to mimic the effect of temporomandibular joint (TMJ) arthroplasty of ankylosis, and distraction at the level of the condylar neck is used to elongate the ascending ramus. The histomorphologic changes of TMJ and distraction gap were investigated. The unilateral condyles and articular discs were extirpated, and the experimental mandibular rami were shortened by 5 mm. An embedded distracter was used to restore the height of the mandibular ramus by unilateral condylar neck distraction (0.8 mm daily for 7 days). A total of 12 adult white rabbits were used, 8 in the experimental group and 4 in the control group. Of the 8 rabbits in the experimental group, 4 each were killed at 4 and 8 weeks after completion of distraction. The TMJ and distracted calluses were harvested and processed for radiographic and histologic examination. An open bite was seen in all rabbits postoperatively that had diminished at the end of distraction. The newly formed condyles radiologically showed remodeling, flattening, and sclerosis. The bony transport disc had gradually remodeled to a new condyle that was similar to the original condyle in appearance and structure. The surface of the transport disc was covered with a fibrous tissue. Moreover, the bony regeneration was perfect in the distraction gap. These results suggest that distraction osteogenesis at the condylar neck using the traditional preauricular approach of TMJ surgery, without the additional incision, can be performed concurrently with arthroplasty of TMJ ankylosis at the same region.

Further observations on retromolar fibreoptic orotracheal intubation in patients with severe trismus

To the Editor, We congratulate Truong et al. on their successful airway management using retromolar fibreoptic orotracheal intubation in a patient with severe trismus undergoing nasal surgery. We too have employed this technique in three adult patients during the past five years. The first case involved a 52-yr-old woman who suffered from a severely limited mouth opening (interincisor distance = 7 mm) due to previous radiotherapy for oral cancer. On this admission, she underwent nasal metastatic tumour excision and temporomandibular joint arthroplasty. The second case involved a 21-yr-old male with chronic temporomandibular joint ankylosis (interincisor distance = 5 mm), mandibular hypoplasia, and left nasal passage stenosis. He was scheduled for temporomandibular joint arthroplasty and surgery of the left nasal passage. The third case involved a 32-yr-old male with decerebrate rigidity secondary to brain trauma. He had severe trismus (interincisor distance = 0 mm), a basal skull fracture, and cerebrospinal fluid rhinorrhea, and he required orotracheal intubation for airway management because his legally responsible relative refused tracheotomy. In all three cases, retromolar fibreoptic orotracheal intubation was an effective choice to secure an airway for patients with concomitant severe trismus and contraindications to nasotracheal intubation. We offer several observations from our experience to facilitate use of retromolar fibreoptic intubation: