Three-dimensional changes in mandibular jaw cysts following decompression surgery: a retrospective cohort study

BACKGROUND: This retrospective cohort study primarily assessed three-dimensional changes in mandibular jaw cysts over time following decompression surgery. Secondary aims included evaluating factors potentially affecting the monthly reduction rates and assessing intra- and interexaminer reliability in the measurements. METHODS: Patients who underwent decompression therapy for mandibular cysts and histopathological diagnosis were included. Cone-beam computed tomography (CBCT) scans obtained before decompression surgery (baseline CBCT) and prior to enucleation surgery (follow-up CBCT) were analyzed using a specialized 3D software to measure cyst dimensions based on preview and final lesion outlines by two examiners. Patient demographics, cyst types, localization, and cortical bone perforation were recorded and evaluated for their influence on dimensional change rates. RESULTS: Forty patients (15 females and 25 males) with a median age of 47 years (range: 11 to 76 years) and treated with decompression of radicular (n = 10), dentigerous (n = 14), botryoid (n = 1), or odontogenic keratocysts (n = 15) were analyzed. The lesions were predominantly located in the posterior mandible (n = 32) and exhibited single (n = 14), multiple (n = 17), or no cortical bone perforations (n = 9). Mean lesion volumes decreased from baseline (3764 mm³) to follow-up (1413 mm³, p < 0.0001), corresponding to an average monthly volumetric reduction rate of -5.2%, without significant differences between the cyst types. Female and younger patients showed higher reduction rates (p ≤ 0.04), whilst localization and cortical bone perforation did not significantly influence the dimensional changes. Both inter- and intraexaminer reliability of measurements were high (intraclass correlation coefficients > 95%). CONCLUSIONS: Decompression surgery is an effective first-stage treatment to reduce the dimensions of large mandibular odontogenic cysts. Within a range of limited clinical relevance, patient-related factors such as sex and age may influence dimensional changes, whereas lesion-specific characteristics did not. Cyst measurements on CBCT were consistent across observers, indicating good reproducibility.