Eric J. Granquist

Total Reconstruction of the Temporomandibular Joint with a Stock Prosthesis

Indications for temporomandibular joint (TMJ) reconstruction include bony ankylosis, failed previousalloplasticandautogenousjointreplacement,posttraumaticcondylarinjury,avascularnecrosis, posttumor reconstruction, developmental abnormalities, functional deformity, and severe inflammatory conditionsthathavefailedtoresolvewithconservativetreatments.SuccessfulTMJreplacementrequires careful preoperative planning, reasonable patient expectations, proper intraoperative technique, regimented postoperative physical therapy, close follow-up, and adequate pain management. Achieving successful TMJ replacementoftenrequires multidisciplinary care from oral and maxillofacial surgeons, pain specialists, internists, physical therapists, and general dentists to optimize patient outcome. Alloplastic joint reconstruction currently offers several advantages compared with autogenous replacements. These advantages include lack of donor morbidity, reduced intraoperative surgical time, immediate functioning, the ability to correct malocclusion (with bilateral replacement), and, most importantly, improved predictability. The most widely used autogenous graft for TMJ reconstruction is the costochondral graft. Compared with alloplastic joint reconstruction, costochondral grafting has a higher complication rate. Complications include graft resorption, overgrowth, and ankylosis. Alloplastic joint reconstruction allows for a stable platform in which retrognathia and facial asymmetry may be corrected in a single surgical procedure. Unacceptable failure rates have been reported in previous alloplastic TMJ implant systems, which haveprovidedvaluableinputforthedevelopmentofnewerimplantsapprovedbytheUSFoodandDrug Administration (FDA). Appreciation of biomechanical and orthopedic principals, along with appropriate clinical trials, has helped in the development of safe and effective devices. These devices still have limitations, such as finite life expectancy, limited translation, the development of wear debris, and the size of the devices. Because fewer patients are requiring revision arthroplasty from previous faileddevices,itcanbeexpectedthatmoreprimaryjointreconstructionwillbeperformedforconditions such as severe inflammatory arthritides, trauma, and ankylosis. A stock prosthetic device has the advantagesofimmediateavailability,single-stagesurgery,noneedforrecapitulationfromastereolithic model, and lower cost. Contraindications to alloplastic joint placement include the presence of active infection, skeletal immaturity, and severe or compromised bone deformity. Patients with severe bone anatomic discrepancies may be candidates for patient-matched custom implants.

Posttraumatic Temporomandibular Joint Disorders

The temporomandibular joint (TMJ) has many essential functions. None of its components are exempt from injury. Facial asymmetry, malocclusion, disturbances in growth, osteoarthritis, and ankylosis can manifest as complications from trauma to the TMJ. The goals of initial treatment include achievement of pretraumatic function, restoration of facial symmetry, and resolution of pain. These same objectives hold true for late repairs and reconstruction of the TMJ apparatus. Treatment is demanding, and with opposing approaches. The following article explores various treatment options for problems presenting as a result of a history of trauma to the TMJ.

Stock Prostheses for Total Reconstruction of the Temporomandibular Joint

Alloplastic total joint replacement (TJR) is a universally accepted procedure in orthopedics. According to recent estimates, the global market for orthopedic implants is projected to reach 46.5 billion dollars by 2017 [1]. The growth has been fueled by the overall safety and efficacy of orthopedic implants and the fact that a steadily increasing aging population and a younger population with higher expectations continue to seek relief from pain and physical independence and maintain mobility and quality of life. In the United States alone, in 2013, there were approximately 330,000 hip replacements and 720,000 knee replacements [2]. In addition to continually improving the safety and performance of alloplastic implants, orthobiologics have also been improving the overall success of orthopedic interventions. Growth factors, synthetic tissue grafts, bioengineered tissue implants, and viscosupplementation substances are only a few of the recent advances.

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.

Advanced maxillofacial imaging for temporomandibular disorder in special needs patients: ADVANCED MAXILLOFACIAL IMAGING

Temporomandibular disorder (TMD) is prevalent in special needs patients. Clinical examination of the temporomandibular joint (TMJ) complex and imaging in this patient population can be challenging due to patient disposition and cooperation. We report a case of a 29-year-old male with neurologic and behavioral special needs who required advanced maxillofacial imaging for a suspected TMD under general anesthesia, which has not been reported previously. This article intends to serve as a resource for health care providers who may encounter similar clinical situations.

Grading facial expression is a sensitive means to detect grimace differences in orofacial pain in a rat model

Although pre-clinical models of pain are useful for defining relationships between biological mechanisms and pain, common methods testing peripheral sensitivity do not translate to the human pain experience. Facial grimace scales evaluate affective pain levels in rodent models by capturing and scoring spontaneous facial expression. But, the Rat Grimace Scale (RGS) has not assessed the common disorder of temporomandibular joint (TMJ) pain. A rat model of TMJ pain induced by jaw loading (1 hr/day for 7 days) was used to investigate the time course of RGS scores and compare them between different loading magnitudes with distinct peripheral sensitivity profiles (0N–no sensitivity, 2N–acute sensitivity, 3.5N–persistent sensitivity). In the 3.5N group, RGS is elevated over baseline during the loading period and one day after loading and is correlated with peripheral sensitivity (ρ = −0.48, p = 0.002). However, RGS is not elevated later when that group exhibits peripheral sensitivity and moderate TMJ condylar cartilage degeneration. Acutely, RGS is elevated in the 3.5N loading group over the other loading groups (p < 0.001). These findings suggest that RGS is an effective tool for detecting spontaneous TMJ pain and that spontaneous pain is detectable in rats that develop persistent TMJ sensitivity, but not in rats with acute resolving sensitivity.

Inter-subject FDG PET Brain Networks Exhibit Multi-scale Community Structure with Different Normalization Techniques

Inter-subject networks are used to model correlations between brain regions and are particularly useful for metabolic imaging techniques, like 18F-2-deoxy-2-(18F)fluoro-d-glucose (FDG) positron emission tomography (PET). Since FDG PET typically produces a single image, correlations cannot be calculated over time. Little focus has been placed on the basic properties of inter-subject networks and if they are affected by group size and image normalization. FDG PET images were acquired from rats (n = 18), normalized by whole brain, visual cortex, or cerebellar FDG uptake, and used to construct correlation matrices. Group size effects on network stability were investigated by systematically adding rats and evaluating local network connectivity (node strength and clustering coefficient). Modularity and community structure were also evaluated in the differently normalized networks to assess meso-scale network relationships. Local network properties are stable regardless of normalization region for groups of at least 10. Whole brain-normalized networks are more modular than visual cortex- or cerebellum-normalized network (p < 0.00001); however, community structure is similar at network resolutions where modularity differs most between brain and randomized networks. Hierarchical analysis reveals consistent modules at different scales and clustering of spatially-proximate brain regions. Findings suggest inter-subject FDG PET networks are stable for reasonable group sizes and exhibit multi-scale modularity.

The Microbiology And Assoicated Risk Factor In Alloplastic Total Joint Infections: A Twenty-Year Retrospective Study

Abstract Purpose Prosthetic joint infection (PJI) is a rare complication of temporomandibular joint replacement (TJR). This study aims to evaluate TJR PJI at our institution over a 20-year period including: microorganisms cultured, antibiotic resistances patterns, and intraoperative protocols of TJR. Patients and Methods Patients were identified using CPT, ICD-9 codes, and surgical logs from January 1995-2015. Inclusion criteria: adults > 18 years with previous total alloplastic joint replacement, and the presence of infection of the prosthetic at explant. Exclusion criteria: patients Results Eleven patients were identified and fifteen joints explanted. Average length in-vivo was 232 months (STD 478.9 months). Six percent (n=1) were identified as early PJI (0-3 months), 46% (n=7) intermediate PJI (3 months- 2 years), and 33% (n=5) late PJI (>2 years). One patient was not able to be classified as early, intermediate, or late. Staphylococcus aureus was present in 53% of subjects and was the predominant organism isolated. Propionibacterium acnes were isolated in 33% of subjects. Penicillin was the antibiotic with the most organism resistance (46%). Conclusion In the current study, the most commonly cultured organisms were Staphylococcus aureus (53%) a finding consistent with current literature. The prevalence of Propionibacterium acnes colonization was noted in 33% of cases. Although the significance of P. acnes and its contribution to PJI still requires further investigation, it is known to be associated with PJI and biofilm formation. Consideration could be given, based on this study, for the use of vancomycin and first generation cephalosporins as perioperative antibiotic coverage .

Microbiology and Associated Risk Factors in Alloplastic Total Joint Infections: A 20-Year Retrospective Study

Abstract Purpose Prosthetic joint infection (PJI) is a rare complication of temporomandibular joint replacement (TJR). This study aims to evaluate TJR PJI at our institution over a 20-year period including: microorganisms cultured, antibiotic resistances patterns, and intraoperative protocols of TJR. Patients and Methods Patients were identified using CPT, ICD-9 codes, and surgical logs from January 1995-2015. Inclusion criteria: adults > 18 years with previous total alloplastic joint replacement, and the presence of infection of the prosthetic at explant. Exclusion criteria: patients Results Eleven patients were identified and fifteen joints explanted. Average length in-vivo was 232 months (STD 478.9 months). Six percent (n=1) were identified as early PJI (0-3 months), 46% (n=7) intermediate PJI (3 months- 2 years), and 33% (n=5) late PJI (>2 years). One patient was not able to be classified as early, intermediate, or late. Staphylococcus aureus was present in 53% of subjects and was the predominant organism isolated. Propionibacterium acnes were isolated in 33% of subjects. Penicillin was the antibiotic with the most organism resistance (46%). Conclusion In the current study, the most commonly cultured organisms were Staphylococcus aureus (53%) a finding consistent with current literature. The prevalence of Propionibacterium acnes colonization was noted in 33% of cases. Although the significance of P. acnes and its contribution to PJI still requires further investigation, it is known to be associated with PJI and biofilm formation. Consideration could be given, based on this study, for the use of vancomycin and first generation cephalosporins as perioperative antibiotic coverage .