Page 345 - Demo

General discussion 34313A comparative meta-analysis was done to evaluate and compare both stock and custom-made TMJR, to help determine the design approach. Although no significantly better post-operative results were found for either system, the remark was made that a potential bias of pooled data had occurred, which benefitted the stock implants.(62) This seems to follow suit with the recent findings by Kanatsios et al.(63), who compared a stock and custom TMJR via a retrospective cohort study. Whereas the included patient did not have a significantly different preoperative maximal mouth opening, the post-operative increase was significantly greater for the custom group compared to those patients treated with a stock prosthesis. Additionally, systematic literature analysis revealed that many surgeons prefer the use of a patient-fitted system in case of more severe anatomical abnormalities, thus leading to additional bias in the meta-analysis.(32,64–66) We found that the use of a PSI has several additional benefits over a stock implant. The custom implant does not require any adaptation of the patient’s anatomy. Surgical time and risk can be reduced. The total contact surface between the implant and the fossa/mandible is improved and no alterations need to be made to the implant itself.(19,67–70) Secondly, several additional corrections can be ‘worked into’ the custom made TMJR, such as an occlusal correction, a substitution of missing bone in cases with a mandibular defect (e.g. hemifacial microsomia, traumatic loss, oncological resection or osteomyelitis defects), thus preventing the need for additional surgery.(68,71,72) Importantly, a load increase in the contralateral healthy TMJ of 15% is seen, when a stock prosthesis is fitted. Over time, this increase in load can result in articular disc damage.(73–75) These advantages were of such significant nature, that it was concluded that the prosthesis we set out to develop, needed to be a custom-made TMJR. To limit the increase in load on the healthy/untreated joint, the center of rotation was kept as close to the axis of its anatomical counterpart rotation as possible, as to allow both joints to move synchronously. This was achieved by keeping the central thickness of the UHMWPE fossa as thin as 2mm. This might mean that a replacement of the fossa-component Nikolas de Meurechy NW.indd 343 05-06-2024 10:15