Surgical management of incidental asymptomatic contralateral inguinal hernias: A retrospective cohort study

Authors

Abstract

Aim Handling asymptomatic contralateral inguinal hernias discovered accidentally via preoperative scans is still debated. This research evaluates surgical strategies and outcomes for individuals with incidental findings versus those with evident symptomatic hernias.
Materials and Methods A retrospective cohort study of 244 patients undergoing inguinal hernia repair from January 2022 to April 2025 at a tertiary care center was conducted. Patients were grouped into those with a symptomatic unilateral hernia and an incidental asymptomatic contralateral hernia (n=42) and those with clinically symptomatic unilateral or bilateral hernias (n=202). Outcomes included operative time, length of hospital stay, and postoperative recurrence. Non-parametric tests and multivariable regression were used.
Results Of 42 patients with incidental contralateral hernias, 52.4% underwent unilateral repair, and 47.6% underwent bilateral repair. Operative time was longer in the incidental group (median 183 vs. 125 minutes, p < 0.001), with no difference in length of hospital stay (median 1 day, p = 0.96). No recurrences were observed. Multivariable analysis confirmed a longer operative time in the incidental group (adjusted ratio, 1.3; 95% CI, 1.1–1.5; p < 0.001).
Discussion Prophylactic repair of incidental contralateral hernias is common but increases operative time without impacting hospital stay. This may reflect short follow-up duration, as the study period extended to April 2025, leaving recent surgeries with limited observation time. Literature suggests that 20–30% of asymptomatic hernias become symptomatic within 2–5 years, supporting prophylactic repair in some cases, particularly with laparoscopic techniques that minimize morbidity.

Keywords

Introduction

Repairing inguinal hernias ranks among the most frequent operations globally, with millions conducted each year [1]. Established methods like laparoscopic and open repairs yield minimal repeat occurrences and reasonable risks for symptomatic cases [2, 3]. The increasing use of preoperative imaging, particularly ultrasound, has led to more frequent detection of asymptomatic contralateral hernias in patients presenting with unilateral symptoms [4, 5]. These incidental findings pose a clinical dilemma: whether to repair the asymptomatic hernia prophylactically during the initial surgery or adopt a watchful waiting approach [6, 7]. The European Hernia Society guidelines recommend laparoscopic bilateral repair for symptomatic bilateral hernias but provide limited guidance for asymptomatic contralateral hernias [8]. Studies suggest that 20–30% of asymptomatic hernias become symptomatic within 2–5 years, supporting prophylactic repair in some cases, especially with minimally invasive techniques that minimize complications [9, 10]. However, prophylactic repair may increase operative time, costs, and risks of complications such as seroma or chronic pain without guaranteed long-term benefits [11, 12]. This retrospective study evaluates the surgical management of patients with a symptomatic unilateral inguinal hernia and an incidental asymptomatic contralateral hernia identified by preoperative imaging at a tertiary care center. We describe the proportion of patients undergoing unilateral versus bilateral repair and compare operative time, length of hospital stays, and postoperative recurrence with patients who have clinically symptomatic unilateral or bilateral hernias. The findings aim to inform decision-making in the context of routine preoperative imaging and contribute to the debate on prophylactic repair.

Materials and Methods

Study Design and Population
This retrospective review occurred at a major medical center, drawing from digital health records of patients receiving inguinal hernia operations from January 1, 2022, to April 30, 2025. The study included 244 adult patients (age ≥ 18 years) with symptomatic inguinal hernias, confirmed clinically or by preoperative imaging (ultrasound or CT). Patients were divided into two groups: (1) 42 patients with a symptomatic unilateral inguinal hernia and an incidental asymptomatic contralateral hernia identified by preoperative imaging, and (2) 202 patients with clinically symptomatic unilateral or bilateral inguinal hernias without an incidental contralateral hernia. Exclusion criteria included emergency surgeries for incarcerated or strangulated hernias, incomplete EMR data, or significant comorbidities contraindicating surgery.
Data Collection
Data were extracted from EMR using a standardized form, capturing demographics (age, sex, body mass index [BMI]), clinical characteristics (main symptom, symptomatic side, hernia diagnosis, preoperative recurrence status, presence of complications such as incarceration), preoperative imaging (ultrasound, CT, or none), surgical details (admission type, operation type [unilateral or bilateral, open or laparoscopic], concomitant procedures, operative time, repair technique [mesh or tissue], surgeon experience), and outcomes (length of hospital stay, postoperative follow-up, postoperative recurrence). Missing BMI values (n=5) were imputed with the cohort mean (26.67 kg/ m²) based on its normal distribution. One missing value for the repair technique was imputed as mesh repair, as 99% of repairs used mesh. Operative time was recorded from operating room sign-in to sign-out in minutes, length of hospital stays in days, and postoperative recurrence was defined as hernia recurrence confirmed by clinical examination or imaging during follow-up.
Statistical Analysis
Descriptive statistics summarized baseline characteristics, with means (standard deviation, SD) for continuous variables and frequencies (%) for categorical variables. The surgical approach for patients with incidental contralateral hernias was analyzed by calculating the proportion of unilateral (open or laparoscopic) versus bilateral (open or laparoscopic) repairs. Outcomes—operative time, length of hospital stay, and postoperative recurrence—were compared between the incidental hernia group and the comparison group. Due to the non-normal distribution of operative time (Shapiro-Wilk test, p < 0.001), the Mann-Whitney U test was used for comparisons. Length of hospital stay, also skewed, was analyzed similarly. Postoperative recurrence was compared using Fisher’s exact test due to low event rates. Within the incidental hernia group, outcomes were compared between unilateral and bilateral repairs using the Mann-Whitney U test. Multivariable linear regression (log-transformed operative time) and logistic regression adjusted for age, BMI, presence of complications, admission type, concomitant procedures, repair technique, and surgeon experience. The comparison group was stratified by symptomatic side (unilateral vs. bilateral) to address heterogeneity in surgical complexity. Sensitivity analyses excluded patients without preoperative imaging (n=8) and those with concomitant procedures (n=29) to assess result robustness. Statistical significance was set at p < 0.05. Analyses were performed using R version 4.2.3.
Ethical Approval
This study was approved by the Ethics Committee of King Abdulaziz University (Date: 2025-09-15, No: 381-25).

Results

Baseline Characteristics
Of 244 patients, 42 (17.2%) had a symptomatic unilateral inguinal hernia with an incidental asymptomatic contralateral hernia identified by preoperative imaging, and 202 (82.8%) had clinically symptomatic unilateral or bilateral inguinal hernias without an incidental contralateral hernia. Table 1 summarizes baseline characteristics. The incidental hernia group had a mean age of 54.8 years (SD 13.7), 95.2% were male, and the mean BMI was 27.5 kg/m² (SD 4.8). All had bilateral hernias by diagnosis (100%), with 76.2% presenting with right-sided symptoms and 23.8% with left-sided symptoms. Preoperative imaging included ultrasound (92.9%) or CT (7.1%). The comparison group had a mean age of 55.6 years (SD 16.2), 94.6% were male, and the mean BMI was 26.5 kg/m² (SD 4.5). Symptomatic sides were 54.5% right, 24.3% left, and 21.3% bilateral, with diagnoses of 52.5% right inguinal hernia, 24.3% left, 21.3% bilateral, and 2.0% femoral. Imaging was performed in 96.0% (88.1% ultrasound, 7.9% CT), with 4.0% having no imaging. No significant differences were found in age, sex, or BMI between groups (p > 0.05).
Surgical Approach in Patients with Incidental Contralateral Hernia
Among the 42 patients with incidental contralateral hernias, 22 (52.4%) underwent unilateral repair (11 open, 11 laparoscopic), and 20 (47.6%) underwent bilateral repair (12 open, 8 laparoscopic) [13]. All repairs used mesh. Bilateral repairs were more common among surgeons with over 20 years of experience (60% vs. 40%, p = 0.15), suggesting a potential influence of surgical expertise on decision-making [14].
Comparison of Outcomes
Table 2 presents outcome comparisons. Operative time was significantly longer in the incidental hernia group (median 183 minutes, IQR 130–239) compared to the comparison group (median 125 minutes, IQR 105–165; p < 0.001). Stratified analysis showed that the incidental hernia group had longer operative time than patients with unilateral symptomatic hernias (n=159, median 120 minutes, p < 0.001) but similar to those with bilateral symptomatic hernias (n=43, median 202 minutes, p = 0.32) [15]. Length of hospital stay was similar between groups (median 1 day, IQR 1–2; p = 0.96), consistent with standard same-day discharge protocols [16]. No postoperative recurrences were recorded in either group (0/42 vs. 0/202), precluding recurrence analysis due to the absence of events. Within the incidental hernia group, bilateral repair had a longer operative time (median 225 minutes vs. 130 minutes, p < 0.001) but no difference in length of hospital stays (median 1 day, p = 0.80).
Multivariable Analysis
After adjusting for age, BMI, presence of complications, admission type, concomitant procedures, repair technique, and surgeon experience, the incidental hernia group had a 1.3-fold longer operative time (95% CI 1.1–1.5, p < 0.001) compared to the comparison group. No significant associations were found for length of hospital stay (p = 0.85).
Sensitivity Analyses
Excluding 8 patients without preoperative imaging did not alter results (operative time p < 0.001). Excluding 29 patients with concomitant procedures showed persistent longer operative time in the incidental hernia group (p < 0.001), confirming the robustness of findings.

Discussion

This study provides real-world evidence on the surgical management of incidental asymptomatic contralateral inguinal hernias identified by preoperative imaging at a tertiary care center. Nearly half (47.6%) of patients with incidental contralateral hernias underwent bilateral repair, suggesting a proactive approach that contrasts with the traditional watchful waiting strategy for asymptomatic hernias [6, 7]. The longer operative time in this group, particularly for bilateral repairs, aligns with the increased surgical complexity of addressing both sides, consistent with prior studies reporting 20–30% longer operative times for bilateral procedures [15, 17]. However, the lack of difference in length of hospital stay indicates that prophylactic repair does not prolong hospitalization, likely due to standardized same-day discharge protocols for elective hernia repairs [16, 18]. The absence of postoperative recurrences in both groups limits conclusions about long-term outcomes. This may reflect short follow-up duration, as the study period extended to April 2025, leaving recent surgeries with limited observation time [19]. Literature suggests that 20– 30% of asymptomatic hernias become symptomatic within 2–5 years, supporting prophylactic repair in some cases, particularly with laparoscopic techniques that minimize morbidity [9, 10]. Our findings show a balanced use of open and laparoscopic approaches, with experienced surgeons more likely to perform bilateral repairs, possibly due to confidence in managing complex cases [14, 20]. The similarity in operative time between the incidental hernia group and bilateral symptomatic cases in the comparison group reflects comparable surgical extent, reinforcing the impact of bilateral repair on operative duration [15]. The high imaging rate (96.7%) strengthens the reliability of group assignments, as preoperative ultrasound or CT scan confirmed the presence or absence of incidental hernias in most patients [4, 5]. The 3.3% without imaging introduces a minor risk of misclassification, but sensitivity analyses excluding these patients confirmed robustness.

Limitations

Limitations include the small sample size for within-group comparisons (n=42), lack of follow-up duration data, and absence of hernia size data, which could influence surgical decisions [21,22]. The retrospective design may also introduce selection bias, as surgeons may choose bilateral repair for healthier patients or larger incidental hernias [23]. Future studies should incorporate longer follow-up, detailed imaging findings (e.g., hernia size), and prospective designs to assess recurrence risks and the natural history of incidental hernias [24,25].

Conclusion

Prophylactic repair of incidental asymptomatic contralateral inguinal hernias is common at our center, occurring in nearly half of cases, but increases operative time without affecting the length of hospital stay. The absence of recurrences suggests short-term safety, but longer follow-up is needed to evaluate recurrence risks and the benefits of prophylactic repair.

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