(38) Case Series of Temporomandibular Joint Reconstruction with Stock Prostheses Utilizing Virtual Surgical Planning

Abstract:

Purpose: Temporomandibular joint dysfunction (TMD) is a complex disease. Temporomandibular joint (TMJ) reconstruction is the last surgical option for patients with end- stage disease who have failed to improve with less invasive surgeries and conservative therapy. Both stock and custom joints have shown improvement in TMJ function and patients’ quality of life.

Custom joints are superior to stock joint in the ability to visualize the osseous anatomy, planned osteotomies, and predictable alignment of the joint components. Traditionally, TJR utilizing stock joints cannot provide presurgical imagery and are predisposed to increased operating time. Time is lost in the operating room exploring the joint anatomy, selecting appropriate joint sizes, and retrofitting the patients’ anatomy to match the stock joints.

In this review, we are proposing using pre - operative virtual surgical planning (VSP) for TMJ reconstruction as a regular practice for stock joints.

Materials and

Methods: We conducted a retrospective case series of all patients who underwent TMJ reconstruction with Biomet Stock joints using virtual surgical planning at Geisinger Health System in Pennsylvania between August 2020 to November 2021. Pre- operative and post-operative computed tomography (CT) scans were obtained. Various radiographic measurements comparing the planned versus surgically placed joints were collected. MedCad was a medical engineering company used for virtual surgical planning. The radiographic measurements assessed the accuracy of the osteotomies along with the position of the mandibular and fossa components. For data analysis, the measurements were reported as median and range. Additionally, these measurement variables were represented visually using histograms. Analyses were performed using R Version 4.0.5 (R Core Team, 2020). 


Results and

Conclusions: A total of 9 patients underwent stock alloplastic implant placement with preoperative VSP. Two of the 9 patients (22.2%) had the procedure performed bilaterally. Additionally, 5 of the 9 procedures were performed by one surgeon, and the remaining 4 were performed by a second surgeon. Of the 11 joints, the condylectomies were completed with a median of 1.6 mm and range of (0.89, 3.10) from the planned osteotomies. The mandibular components were placed with a median of 0.23 mm and 0.49 mm to the posterior and the inferior borders of the mandible, respectively. The fossae components were placed within 1.2 mm from the virtually planned position in both horizontal and vertical planes.

Being mindful of the limited number of reported cases in this series, this case series will serve as a pilot study to further investigate the use of virtual surgical planning in TMJ reconstruction with stock joints.

Future research will compare the accuracy, operative time, complications incidence, and financial values to the conventional modalities (custom joints and stock joints).