OKC is one of the most aggressive cyst among odontogenic cystic lesions. Though OKC is not known to metastasize, it can induce resorption, expansion of the jaw and change of the facial profile as it grows. Although in comparison with a small number of studies, prevalence in this study was higher in 10 to 30-year-old patients, consistent with a previous study [7]. One-third of patients were asymptomatic and usually diagnosed by routine dental examination; 50% of them complained of jaw swelling and mild pain [8, 9]. Though rare, conversion to malignant deviation such as primary intraosseous squamous cell carcinoma (PIOSCC) of the jaw is possible.
There are several studies on the differences in recurrence according to the treatment modalities of OKC. Kaczmarzyk et al. report that, the overall recurrence rate of OKC was 23.15%. The recurrence rates were followed by treatment modalities were 0% for resection, 0% for enucleation with peripheral ostectomy and Carnoy’s solution, 18.18% for enucleation with peripheral ostectomy, 26.09% for enucleation alone, 40% for marsupialization without following enucleation, and 50% for enucleation with Carnoy’s solution [10]. The most obvious way to prevent recurrence of OKC is resection. But this is a very invasive surgical procedure. In a review study of OKC in Blanas et al., simple enucleation was reported to have a recurrence rate of 17% to 56% [11]. The recurrence rate of simple enucleation of OKC is very high. However there are several reports of a low recurrence rate after decompression following enucleation of OKC (0–8.7%) [4, 12,13,14].
The decompression and second-stage enucleation of OKC might be the first choice of treatment in terms of functional and esthetic reconstruction. In cases of huge cystic size and proximity with vital anatomic structures, decompression is the most proper treatment. During the decompression period, an opening by appliance allows for drainage of fluid which consists of OKC. This leads to decreased intracystic pressure [15] and bone formation along the periphery of the cystic wall, regardless of the direction of either MD or BL. Decompression and second-stage enucleation can thus be deemed beneficial in terms of decreased complications (nerve injury, pathologic fracture, discomfort).
The volume of OKC was reduced by 25, 50, and 75% over 103, 270, and 727 days of decompression. The surgeons in our department decided timing for enucleation based on the amount of discharging fluid and detachment from important anatomical structure in panoramic and CT images. The average decompression duration of study group was 298 days in this way. The time to enucleation based on the reduced exudate clinically and volume change as observed by the surgeon (298 days) was similar with the time of 50% reduction rate of OKC (270 days). Therefore, enucleation time set by the surgeon seems appropriate.
Tube length during decompression should be continuously adjusted as the OKC decreases in size. Amount of decrease can be confirmed by both panoramic view and CT. However, investigation by panoramic view is limited as evaluation of buccolingual dimension and volume are close to impossible [15]. In this respect, CT yields more information than 2D imagery. Therefore, panoramic images should be taken during periodic follow-up, CT being taken when there is a necessity for more accurate confirmation.
A relatively low recurrence rate was observed in this study when decompression was followed by enucleation. Moreover, the final pathology report was coincided with that of incisional biopsy performed in decompression procedure.