Radiographic Assessment of Inflatable Penile Prosthesis Reservoir Location Variability in Contemporary Practice. Issue 12 (6th November 2021) - Kavoussi, Mehraban
ABSTRACT: Background: Inflatable penile prosthesis (IPP) reservoirs are typically placed into the Space of Retzius (SOR) or alternative locations including the High Submuscular (HSM) space via transinguinal (TI) or counter incision (CI) techniques. A cadaver study showed variability in reservoir location after TI-HSM placement. Aim: To evaluate reservoir location using cross-sectional imaging following IPP insertion. Methods: We retrospectively reviewed our institutional database and identified men who underwent virgin penoscrotal IPP insertion between 2007 and 2019. We then identified those men who subsequently underwent cross-sectional imaging prior to October 2019. Radiologists evaluated cross-sectional imaging in a blinded manner and categorized reservoir locations as follows: 1) submuscular; 2) posterior to the external oblique fascia and lateral to the rectus abdominis musculature; 3) preperitoneal; 4) retroperitoneal; 5) intraperitoneal; 6) inguinal canal; 7) subcutaneous. Patients were stratified by reservoir placement technique, transinguinal space of Retzius (TI-SOR), transinguinal high submuscular (TI-HSM), or counterincision high submuscular (CI-HSM). Clinical characteristics and outcomes were reviewed and compared. Statistical analysis was performed using Chi-squared and Fisher's exact tests. Outcomes: Variability exists in the TI placement of SOR and HSM reservoirs, CI-HSM reservoirs were associated with a low level of variability. RESULTS: Among 561 men who underwent virgin IPP insertion during the 12-year study period, 114 had postoperative cross-sectional imaging (29 TI-SOR, 80 TI-HSM, and 5 CI-HSM). Among the 114 patients imaged, TI-HSM reservoirs were more likely than TI-SOR to be located anterior to the transversalis fascia (48 vs 14%, P < .01) and were less likely to be located in the preperitoneal space (18 vs 62%, P < .01). Rates of intraperitoneal reservoir location were similar between the TI-HSM and TI-SOR groups (5 vs 7%, P = .66). Among imaged CI-HSM reservoirs, 4 (80%) were anterior to the transversalis fascia and 1 (20%) was within the inguinal canal. Among all 536 transinguinal cases (131 TI-SOR and 405 TI-HSM), rates of reservoir-related complications requiring operative intervention were similar between groups (5 vs 2%, P = .24). No complications were noted among the 25 patients in the CI-HSM cohort. Clinical Implications: The level of variability seen in this study did not seem to impact patient safety, complications were rare in all cohorts. Strengths and Limitations: This study is the first and largest of its kind in evaluating reservoir positioning in live patients with long-term follow-up. This study is limited in its retrospective and nonrandomized nature. CONCLUSIONS: Despite variability with both TI-HSM and TI-SOR techniques, reservoir related complications remain rare.