A prospective cohort study was performed of patients undergoing the implantation of an IPP at a single ASC to evaluate the safety and effectiveness of outpatient IPP procedures utilizing postoperative metrics including emergency room visitation, hospitalization rates, postoperative infections, and the need for additional prescription of analgesia. Furthermore, OR times and post-anesthesia recovery duration were assessed to underscore the procedural advantages of outpatient IPP surgeries. This study was approved by the University of Manitoba’s Health and Research Ethics Board (HS26331).
Study Population and Data Collection
All IPP implantation procedures were performed at a single urologic ASC outpatient clinic from February 2023 to April 2024 by two surgeons. Procedures were performed under spinal anesthesia (SA) or deep intravenous sedation (DIVS). All patients receiving an IPP implantation at the ASC were included in the study. Patients deemed ineligible for outpatient surgery and who were resultingly excluded, included those preferring general anesthesia (GA), those deemed American Society of Anesthesiologists (ASA) 4 or above, patients unstable ASA 3, and those with severe obstructive sleep apnea who were not CPAP compliant.
Patient demographics were collected, including age, body mass index (BMI), Charlson Comorbidity Index (CCI), and history of pelvic surgery or radiation. Prosthetic parameters were also collected, including combined implant size (cylinder and rear tip length) and location of reservoir placement. Moreover, the following intraoperative complications were assessed: conversion to GA, perioperative patient procedural intolerability, concerns related to respective anesthesia, and procedure abortion. OR records were accessed to collect surgical parameters, specifically duration of surgery (defined as the time of incision to time of dressing) and post-anesthesia recovery (PAR) time (defined as the time of entry into the post-anesthesia recovery room to time of leaving the clinic). Postoperative complications, including hospital admission, urgent care or emergency room visits, prescription of additional analgesia, and incidence of infection were assessed four-to-six weeks postoperatively. Postoperative complication data was collected and assessed prospectively utilizing REDCap electronic data capture tools hosted at the University of Manitoba.(11,12) REDCap (Research Electronic Data Capture) is a secure, web-based software platform designed to support data capture for research studies.
Anesthesia Selection Process
Anesthesia selection was predominantly driven by patient-related factors following consultation with an anesthesiologist. Patients were largely offered SA, with deep intravenous DIVS only being offered if any of the following criteria were met: patient refusal of SA, patient preference to have DIVS, patients with a history of complications from SA, prior history of prolonged anesthesia duration from SA, patients with spinal deformities, patients with coagulopathy, patients with fixed cardiac output states, patients with indeterminate neurological diseases, or patients with raised intracranial pressure. The outpatient centre at which procedures took place was approved for DIVS halfway through the study, which may have limited further selection of sedation as an anesthetic option before this date.
Anesthetic and Procedural Protocol
Low-dosage spinal was provided to patients receiving SA, utilizing the sitting aseptic technique. 2% lidocaine was applied to the skin at the spinal level of L3/L4. A 25 gauge Whitacre spinal needle with introducer was used to administer 0.7 to 0.8 mL of 0.75% Marcain heavy, alongside 10µg of fentanyl. The level of SA blockage was up to the T10 dermatome, which was tested with ice. All SA patients also received mild sedation consisting of intravenous midazolam (2-4mg) and propofol (25-100µg/kg/min), throughout the perioperative period.
DIVS was administered and monitored by an anesthesiologist with induction involving IV midazolam (5mg) and ketamine (20mg), with maintenance consisting of a continuous infusion of propofol (30-50µg/kg/min) and remifentanil (0.05µg/kg/min). Level of sedation, and ultimately deep sedation, was confirmed by the anesthesiologist as per the Modified Ramsay Sedation Score of level 5 to 6, with patients being asleep with a sluggish response or unarousable in most cases. Adjunct peripheral nerve blocks were also performed, with all patients receiving a combination of bilateral ilioinguinal nerve blocks, crural pudendal block, and dorsal penile block using a local anesthetic (LA) mixture consisting of 15 mL of 1% lidocaine and 15 mL of 0.25% marcaine, in equal aliquots. Bilateral ilioinguinal nerve blocks were established utilizing the landmark approach by the anesthesiologist. The crural pudendal and dorsal penile blocks were established by the operating surgeon. The same mixture of LA was applied to the dermal layer at the site of incision pre- and post-operatively for immediate and prolonged analgesia, respectively.
After induction of anesthesia, all procedures were performed via an infrapubic approach as described by Perito PE (2008), with Irrisept used to irrigate the surgical site.(13,14) The placement of reservoirs was based on prior pelvic surgical and treatment history, namely bilateral hernia repair, pelvic radiation, and radical prostatectomy. Patients with surgically naïve or uncompromised pelvises had reservoirs implanted into the Space of Retzius (SOR), whereas, in patients with compromised pelvises, the submuscular space was utilized instead. Post-operatively, Bactrim DS twice daily for five days was prescribed, along with celecoxib 200mg once daily, acetaminophen 500mg once every six hours, and gabapentin 300mg every eight hours as needed for analgesia.
Data Analysis
Patient charts managed and collected prospectively using REDCap. All data was de-identified following collection, which occurred four-to-six weeks following procedures from patient follow-up appointments at the ASC. All data was analyzed descriptively with raw percentages, with the mean and standard deviation reported where appropriate. Differences across the two anesthesia cohorts were assessed for statistical significance, particularly in the patient demographics and surgical parameters. In light of the unequal variance and size in the SA and DIVS cohorts, Welch’s t-test was utilized to assess for any difference in the patient demographic information (age, BMI, and CCI) and surgical parameters across the two anesthesia groups with p<0.05 being considered statistically significant.