Combined Transnasal, Transoral Excision of Odontogenic Cysts Offers Reduced Recurrence Rates and Favorable Sinonasal Outcomes

Odontogenic cysts impact the adjacent dentition and maxillary sinus. A combined transnasal, transoral approach for removal offers reduced recurrence rates and favorable sinonasal outcomes compared with historic transoral-only approaches. Odontogenic cysts are fluid-filled, epithelial-lined cavities of dental origin with the potential to damage adjacent dentition and maxillary sinus with associated sinonasal symptomatology.1 These cysts can be developmental or inflammatory and include diverse pathologies such as odontogenic keratocysts (OKCs), dentigerous cysts, and radicular cysts among others.2-4 The standard of care has been transoral excision with extraction of involved teeth. However, for large cysts, a transoral-only approach limits access to the entire lesion and requires greater bony exposure, with the potential for incomplete excision. Publications have shown high rates of oroantral fistula formation, loss of dentition, and cosmetic deformity.5 In addition, recurrence rates following transoral excision range from 14%–35%, which is of particular significance for pathologies with the propensity to be locally aggressive, including OKC and cyst with ameloblastic transformation.6 Endoscopic approaches to sinonasal inflammatory disease are common, and have been utilized for extended approaches to complex skull base lesions.7-10 It is thus logical that the approach could be applied to odontogenic lesions. Previously, case series have demonstrated that an endoscopic approach to odontogenic cysts results in decreased morbidity; however, small sample sizes have limited conclusions.11 Here, we present the largest case series in the literature of odontogenic cysts managed jointly by rhinologic and oral and maxillofacial surgeons (OMFS) through a combined transnasal, transoral endoscopic approach. This study received Institutional Review Board approval. A retrospective review was performed of patients undergoing combined transnasal, transoral odontogenic cysts excision from 2012 to 2023. Patients were included if managed jointly by rhinology and OMFS. Patients with non-cystic pathologies (e.g., oroantral fistulas) were excluded. The combined approach consisted of transnasal endoscopic maxillary antrostomy, total ethmoidectomy, and medial maxillectomy by rhinology, and transoral partial maxillectomy and dental extraction by OMFS. A two-team approach facilitated endoscopic exposure transnasally and transorally with angled endoscopes utilized as needed to ensure complete cyst wall removal. When indicated a buccal fat pad advancement flap closure is performed by OMFS. Demographic data, clinical history, and results of the 22-item sinonasal outcome test (SNOT-22)12 were collected. Pre- and posttreatment SNOT scores were compared using two-tailed paired t-tests with p < 0.05. Figure 1 presents two case examples. Of a total 41 patients being treated by the rhinology and OMFS teams, 23 met inclusion criteria (56.52% male, mean age 44.61 years). Cysts were 3.37 cm in average maximal diameter (range 0.80 to 4.83 cm). Pathology included OKC (52.17%), dentigerous cyst (17.39%), cyst with ameloblastic transformation (13.04%), radicular cyst (8.70%), and ossifying fibroma and chondromyxoid fibroma (4.35% each). There were two recurrences (8.70%), both OKCs, over an average follow-up time of 2.66 years. Revision surgery resulted in no evidence of recurrence at 1.20 years postoperatively. There was no significant difference in recurrence by pathology (p > 0.999). Preoperative average total SNOT scores were 19.57 with no significant difference by pathology (p = 0.359). There was a significant improvement in SNOT score at second postoperative visit (first: average mean change [∆]: 1.10, confidence interval [CI] −10.09 to 12.29, p = 0.934), however, this was not present at first and third postoperative visits (second: ∆-7.53, CI −14.09 to 0.97, p = 0.046; third: ∆-7.67, CI −14.72 to 0.62, p = 0.138). There was no significant difference in postoperative SNOT score when stratified by pathology (p = 0.359). Rhinologic sub-score showed a significant improvement at third postoperative visit (first: ∆1.59, CI −2.74 to 5.92, p = 0.819; second: ∆-1.74, CI −5.52 to 2.05, p = 0.404; third: ∆-4.41, CI −7.05 to −1.77, p = 0.039). Again, there was no significant difference in rhinologic sub-score by pathology (p = 0.5183). There were no changes in total SNOT and rhinologic sub-score above the minimal clinically important difference (MCID). We demonstrate that a combined transnasal, transoral endoscopic approach for odontogenic cysts excision is a safe alternative to open transoral approaches and results in a recurrence rate 33%–75% below that of prior publications. This is likely due to an enhanced ability to address the source of the cyst, the tooth, and to facilitate complete cyst wall excision. Importantly, the approach does not require new technology beyond the combined rhinology and OMFS skill sets, and allows for long-term defect reconstruction based on dental rehabilitation plan. The two-team approach is perhaps the greatest asset of this technique, and the use of angled endoscopes is of particular importance when working in this corridor. Furthermore, one might anticipate increased sinonasal symptomatology with the transnasal approach; however, we demonstrate no increased sinonasal morbidity. There was a trend toward long-term improvement in rhinologic subdomain score, though not greater than the MCID. Transnasal endoscopic approaches continue to show utility in the management of diverse pathologies. This case series represents the largest currently in the literature of a combined transnasal, transoral approach to odontogenic cysts. This approach capitalizes on the synergistic skill set of both rhinology and OMFS. We thus recommend that this approach be considered for management of odontogenic cysts involving the maxillary sinus, providing optimized patient care, reduced recurrence rates, and no added sinonasal morbidity.