Endoscopic Resection of Maxillary Sinus Inverted Papilloma Vincent Wu BHSc(H)1,2, Jennifer Siu MD3, Jonathan Yip MD3, John M. Lee MD FRCSC MSc2,3 1School of Medicine, Faculty of Health Sciences, Queen’s University; 2Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael’s Hospital; 3Division of Rhinology, Department of Otolaryngology – Head &Neck Surgery, St. Michael’s Hospital, University of Toronto Background Results Results Inverted papillomas (IP) most commonly develop in the maxillary sinus, particularly from the medial wall1,2 Maxillary sinus IPs have traditionally been resected via an endoscopic endonasal approach with adjunctive external procedures (ex. canine fossa and Caldwell-Luc approaches) when necessary2-4 The number and location of attachment sites for IP affects the surgical approach utilized5 Prognosis based on number of IP attachment sites within maxillary sinus has not been thoroughly identified in the literature Figure 2: CT of Left Maxillary Sinus IP Table 3: Wall of Maxillary Sinus Involved in Cases with Single Attachment Posterior 1 Inferior Lateral 2 Anterior Medial 8 Superior IPs with single attachment (46%) were predominantly to the medial walls Hyperostosis along maxillary sinus floor is suggestive of IP attachment site Table 4: Wall of Maxillary Sinus Involved in Cases with Multifocal Attachments Posterior 7 Inferior Lateral 9 Anterior Medial 10 Superior 3 Figure 3: MRI of Left Maxillary Sinus IP Figure 1: Maxillary Sinus IP – Pre-Operative and Post-Operative Imaging IPs with multifocal (54%) attachments were predominately to the medial, lateral, and anterior walls Table 5: Surgical Approaches Medial Maxillectomy 28 Ethmoidectomy 23 Frontal Sinusotomy 10 Sphenoidotomy 4 Partial Middle Turbinate Resection 5 Septoplasty DCR 2 T2 weighted MRI showing the convoluted cerebriform pattern of IP Objective Evaluate the effectiveness of a pure endoscopic approach for resecting IPs originating from the maxillary sinus Method All cases involved a medial maxillectomy to access to IP Single-center, single-surgeon (JML) retrospective chart review All maxillary sinus IP patients who underwent surgical resection from January 1, 2010 to June 30, 2016 were identified and included for analysis Outcome measures: patient demographic, operative technique, IP sites of attachment, follow-up, and IP recurrence Discussion Despite the majority of patients having multiple maxillary IP attachment sites, all patients were managed with a pure endoscopic approach Anterior and inferior wall IPs, often require combined approach due to difficult access, were managed only with an endoscopic medial maxillectomy in our series2 No difference in outcomes between single vs. multi-site IP attachments with regards to operative technique, LOS, recurrence, or intraoperative complications Limitation: short follow-up duration of 18.9 months, since up to 20% of IP recurrence can occur 5 years after surgery6 Maxillary IPs with multifocal attachments most frequently involved 2-3 walls of the sinus Table 2: Number of Walls Involved in Cases of Multifocal Attachment of IP Number of walls involved Number 1 2 5 3 4 6 Total 15 Results Table 1: Patient Demographics Total patient (n) 28 Gender (M:F) 17:11 Age, years (mean, SD) 54.9 (16.5) Prev. recurrence (n, %) 10 (36%) Recurrence (n, %) 0 (0.0%) Malignancy (n, %) 1 (3.6%) Follow up, months (mean, SD) 18.9 (13.9) Length of stay, days (mean, SD) 0.68 (1.3) Intraoperative complications (n) IPs originating from the maxillary sinus frequently had multi-focal attachments Two patients had multiple attachments to one wall Conclusion Despite surgical challenges of reaching all walls, maxillary IPs may be managed effectively via a pure endoscopic approach References: 1. Buchwald C, Nielsen LH, Nielsen PL, Ahlgren P, Tos M. Inverted papilloma: a follow-up study including primarily unacknowledged cases. Am J Otolaryngol. 1989 Aug;10(4):273-81. 2. Hong SL, Mun SJ, Cho KS, Roh HJ. Inverted papilloma of the maxillary sinus: Surgical approach and long-term results. Am J Rhinol Allergy. 2015 Nov-Dec;29(6):441-4. 3. Krouse JH. Endoscopic treatment of inverted papilloma: safety and efficacy. Am J Otolaryngol. 2001 Apr;22(2):87-99 4. Hyams VJ. Papillomas of the nasal cavity and the paranasal sinuses, a clinicopathologic study of 315 cases. Ann Otol Rhinol Laryngol. 1971;80(2):192–6. 5. Yoon B, Batra PS, Citardi MJ, Roh H. Frontal sinus inverted papilloma: Surgical strategy based on the site of attachment. Am J Rhinol Allergy. 2009 May;23(3):337-41. 6. Jiang XD, Dong QZ, Li SL, Huang TQ, Zhang NK. Endoscopic surgery of a sinonasal inverted papilloma: Surgical strategy, follow-up, and recurrence rate. Am J Rhinol Allergy. 2017 Jan 1;31(1):51-55.