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Purpose: Treatment of tumors arising in the upper parapharyngeal space (PPS) or the floor of the middle cranial fossa is challenging. This study aims to present anatomical landmarks for a combined endoscopic transnasal and anterior transmaxillary approach to the upper PPS and the floor of the middle cranial fossa and to further evaluate their clinical application. Methods: Dissection of the upper PPS using a combined endoscopic endonasal transpterygoid and anterior transmaxillary approach was performed in six cadaveric heads. Surgical landmarks associated with the approach were defined. The defined approach was applied in patients with tumors involving the upper PPS. Results: The medial pterygoid muscle, tensor veli palatini muscle and levator veli palatini muscle were key landmarks of the approach into the upper PPS. The lateral pterygoid plate, foramen ovale and mandibular nerve were important anatomical landmarks for exposing the parapharyngeal segment of the internal carotid artery through a combined endoscopic transnasal and anterior transmaxillary approach. The combined approach provided a better view of the upper PPS and middle skull base, allowing for effective bimanual techniques and bleeding control. Application of the anterior transmaxillary approach also provided a better view of the inferior limits of the upper PPS and facilitated control of the internal carotid artery. Conclusions: Improving the knowledge of the endoscopic anatomy of the upper PPS allowed us to achieve an optimal approach to tumors arising in the upper PPS. The combined endoscopic transnasal and anterior transmaxillary approach is a minimally invasive alternative approach to the upper PPS. [ABSTRACT FROM AUTHOR]

Background: To determine the learning curve with cumulative sum analysis for endoscopic resection of juvenile nasopharyngeal angiofibroma (JNA) and investigate whether the surgeon's expertise is a risk factor for recurrence.Materials and Methods: We reviewed the medical records of patients with JNA who underwent endoscopic or endoscopic-assisted surgery between 2006 and 2015. We used cumulative sum (Cusum) analysis to plot the learning curve for operation time versus chronological sequence, and verified the Cusum curve by risk-adjusted Cusum (RA-Cusum) analysis. We identified three phases of expertise. The recurrence rate was analyzed using the Kaplan-Meier method and log-rank tests. A multivariable Cox regression analysis was performed to identify the independent risk factors for recurrence.Results: We included 154 JNA patients with a median age of 16 years. The surgeon overcame the learning curve after case 80 with increasing surgical efficiency and competence. The learning curve plotted by Cusum analysis divided the cases into three phases: phase 1, accumulation of initial experience (cases 1-41); phase 2, further accumulation of experience (cases 42-117); and phase 3, mastering the procedure (cases 118-154). Pearson's χ2 tests showed that tumor stage (P = 0.021), blood loss (P = 0.001), operation time (P < 0.001), and phase (P < 0.001) were associated with recurrence. The log-rank test showed that time to recurrence was significantly shorter in phase 1 than in phases 2 and 3. Blood loss and phase were independently prognostic factors for time to recurrence, with P values of 0.023 and 0.009, respectively. The RA-Cusum analysis identified two inflection points of the curve at case 44 and 83, and verified the results of Cusum analysis.Conclusion: Surgical experience and competence with endoscopic resection affect the recurrence rate in JNA patients.Level Of Evidence: 4. [ABSTRACT FROM AUTHOR]