Posterior Ethmomaxillary Cells: Anatomical Variation to be Considered in Endoscopic Sinus Surgery

To identify the posterior ethmomaxillary (PEM) cells on computed tomographic scans for complete sinus clearance during endoscopic sinus surgery to prevent disease recurrence. Prospective single institution study. MAA ENT Hospitals Pvt. Ltd., Hyderabad. 350 patients were selected for the study. Computed tomographic scans of these patients were performed suffering from chronic rhinosinusitis and requiring endoscopic sinus surgery (primary or revision cases). The scans were evaluated and presence of PEM cells was noted. These findings were co-related intra-operatively and above-mentioned cells were opened. In revision cases, these cells were left unopened in previous cases and were cleared in present surgery and the patients were followed up for recurrence. A total number of 350 CT scans of nose and para-nasal sinus were studied. There were 176 males and 174 were females. The presence of PEM cells was 11.42% with bilaterality in 80%. In revision cases, it was 23%. PEM cells act as hidden areas in the para-nasal sinus and if not identified and cleared, it acts as a nidus for disease recurrence and cause for failure of surgery. Identification of PEM is important during surgery for complete disease clearance. As very little information exists in the current literature, we are submitting this study to enlighten Rhinologist regarding PEM cells.