(40) How Do Non-Keratocystic Lesions Respond to Decompression Tube Placement?

Abstract: Decompression is a treatment modality that reduces the internal pressure of intrabony cystic lesions of the maxilla or mandible which subsequently induces bone deposition and decreases cystic size. A current standard practice when biopsying radiographically large intrabony lesions is to place decompression tubes if these lesions contain cystic linings. This treatment modality has been shown to decrease lesion volume, cystic lining thickness, and cyst wall histologic appearance in multiple studies involving the odontogenic keratocyst. In a recent retrospective cohort study at the University of Illinois–Chicago (UIC) Department of Oral and Maxillofacial Surgery, a number of non-keratocystic lesions treated between January 2017 and January 2022 were identified and descriptive statistics were outlined demonstrating the potential outcomes following decompression. Building on this work, the purpose of this study was to perform volumetric analysis to determine if any size reduction benefit existed in decompression for non-keratocystic lesions. Subjects were identified through surgical logs and chart queries. IRB approval was obtained from UIC (IRB #2022-0071).

Eighty-three subjects (34 female; 49 male) were identified with an average age of 32.8 years. The most common lesion was dentigerous cyst (n = 45, 54.2%) with an average percent change of 68.39% and average rate of change of -0.027 cm3/day, followed by periapical cyst (n = 12, 14.5%) with an average percent change of 40.84% and average rate of change of -0.016 cm3/day. Ameloblastoma (n = 7, 8.4%) was next with an average percent change of 30.91% and average rate of change of -0.059 cm3/day, followed by Inflammatory cyst (n = 5, 6.0%) with an average percent change of 45.24% and average rate of change of -0.020 cm3/day. Most subjects were eventually treated with enucleation and curettage (n = 52, 62.7%) with an average percent change of 59.24% prior to treatment, followed by resection with or without reconstruction (n = 12, 14.5%) after an average percent change of 71.65% prior to treatment, and 9 cases (10.9%) showed resolution with eventual removal of decompression tubes. There was a statistically significantly higher percent change in lesion size for dentigerous cysts compared to the other studied lesions (P = .046), however there was no significant difference identified for rate of change of lesion size between any lesion types (P = .46). While three of the ameloblastoma lesions identified in this study ultimately underwent resection with free flap reconstruction, and two lesions increased in size prior to enucleation and curettage, with such a small sample size of ameloblastoma lesions, the clinical validity of the overall size decrease benefit for the ameloblastomas primarily treated with decompression observed in this study is questionable. There was, however, a clear benefit for decompression of the other studied non-keratocystic lesions. While further work is needed to identify if this trend persists in larger populations, the size decrease trend for the other non-keratocystic lesions identified in this study could demonstrate a decrease in surgical morbidity for subjects who would otherwise require resection of larger volumes of hard and soft tissue, thus impacting their function less. While the results of this study support the utilization of this treatment modality as a default treatment following initial biopsy, caution should be taken, given the low likelihood for resolution or even size decrease in ameloblastoma lesions. Despite these potential benefits, it is important to be cognizant that decompression tube placement can be technically challenging, and appropriate maintenance, irrigation, and close follow-up by the patient is imperative.