Open inguinal hernia (IH) repair is one of the most common general surgery operations. It can be conducted under general, spinal or local anesthesia. Postoperative urinary retention (POUR) is a common complication after inguinal hernia repair, ranging from 0-40% depending on the type of anesthesia used, reaching higher percentages when the operation is performed under regional anesthesia [1]. Despite the high rates of POUR, open inguinal hernia repair under spinal anesthesia remains popular among surgeons, anesthesiologists and patients. The aim of this study is to investigate the perioperative risk factors of POUR in patients undergoing elective open inguinal hernia repair under spinal anesthesia.

This is a prospective study, enrolling male patients elder than 50 years old, eligible for IH repair. Exclusion criteria were emergency surgery, benign prostatic hypertrophy under medication, history of open or endoscopic lower urinary tract surgery, neurological conditions under medication, ASA Score ≥3, IH repair under general or local anesthesia. All patients were submitted to open inguinal hernia repair with mesh placement. Possible factors of POUR that were recorded were age, comorbidities, previous abdominal operations, Body Mass Index (BMI), International Prostate Symptom Score (IPSS), nocturia, preoperative Anxiety Visual Analog Scale score (A-VAS), recurrent hernias, postoperative Pain Visual Analog Score (P-VAS), perioperative use of intravenous (IV)/spinal opioids, perioperative administration of IV fluids, intraoperative administration of atropine, European Hernia Society (EHS) hernia Classification, operation duration, type of hernia, posterior wall reinforcement and hernia sac size. Postoperative urinary retention was defined as the inability to void urine up to 8 hours after surgery. Statistical analysis has been performed according to multivariate analysis for non-parametric samples and a cut-off value for statistical significance of 0.05 with SPSS v26 (IBM Corp. 2017. IBM SPSS Statistics for Windows. Armonk, NY: IBM Corp.).

141 consecutive male patients have been enrolled in this study with a mean age of 63.5 years. The incidence of postoperative urinary retention was 36.1% (51 patients). All patients with POUR were catheterized using a foley catheter. Catheter removal was successful 24 hours after surgery in 46 patients (90.2%), in 3 patients (5.9%) the catheter was removed 48 hours after surgery, while 2 (3.9%) patients required prolonged catheterization. Studied parameters which reached statistical significance at multivariate analysis, were comorbidities, IPSS score, nocturia, posterior wall reinforcement (PWR), preoperative high A-VAS score and intraoperative use of atropine. At the logistic regression model (OR 95%CI) only comorbidities (p=0,04), PWR (p=0,006) and high A-VAS score (p=0,043) were found to be statistically significant. 49% of the patients had no comorbidities, 28% had one, 20% patients had two and 3% patients had more than two. The most common condition under medication was arterial hypertension (53/72). Most common causes of anxiety among patients with high A-VAS score were anxious personality (12/29), operation (8/29) and anesthesia (4/29).

In our study we found a high incidence of POUR comparing to literature [1]. We attribute our results to the fact that we only included males over 50 years old, all repairs were performed under spinal anesthesia and we set a small time interval from surgery to urinary retention diagnosis. Perioperative parameters that were identified as prognostic factors of POUR in our study were IPSS and nocturia, intraoperative use of atropine, comorbidities, posterior wall reinforcement and preoperative high A-VAS score.
Comorbidities were identified as a predictive factor of POUR. In our study we included patients with a low ASA score and mild systemic diseases such as arterial hypertension, dyslipidemia and hyperuricemia but under medication with a variety of drugs, making it impossible to identify any specific drug that could predispose to POUR. 
Posterior wall reinforcement is usually performed in patients with large direct hernias to reinforce the repair and/or to facilitate mesh placement. Suturing of the trasversalis fascia to the Cooper ligament before mesh placement is not superior to tension free techniques and it increases the possibility of urinary retention and should be avoided [1].
According to our results preoperative anxiety leads to increased rates of POUR. This is to the best of our knowledge the first study to investigate preoperative anxiety as a predictive factor of POUR. The use of Anxiety VAS score is an easy and accurate way to preoperatively identify patients who are in danger of developing postoperative urinary retention. According to the existing literature a patient was considered anxious with 51mm or more on the VAS scale [2].  In this group of patients, a different approach should be used, such as thorough explanation of the procedure and anesthesia technique along with premedication in order to reduce anxiety levels or even a different anesthetic approach.

Postoperative urinary retention after open inguinal hernia repair is more likely to be present in male patients with comorbidities, high Anxiety VAS score and posterior wall reinforcement. Further investigation with studies on larger series and less limitations are needed to obtain clear messages and guidelines.

Baldini G, Bagry H, Aprikian A, Carli F, et al. Postoperative urinary retention: anesthetic and perioperative considerations. Anesthesiology. 2009, 110:1139-57. 10.1097/ALN.0b013e31819f7aea
Facco E, Zanette G, Favero L, et al. Toward the validation of visual analogue scale for anxiety. Anesth Prog. 2011, 58:8 13. 10.2344/0003-3006-58.1.8

Continence 2S2 (2022) 100224
DOI: 10.1016/j.cont.2022.100224