Testicular Pain Following Laparoscopic Donor Nephrectomy: An Underreported Complication

Introduction

Laparoscopic donor nephrectomy (LDN) has become the established approach for living kidney transplantation. ^{1 –3} Despite well-documented postoperative complications, postoperative testicular pain (TP) remains relatively understudied. ^{4 –6} While several studies have been published in the past two decades, the reported incidence of TP after LDN differs significantly across studies, ranging from 6.2% to 55%. ^{7 –15} Furthermore, the underlying mechanisms of this pain are not well understood. Thus, this study aimed to comparatively analyze the incidence, characteristics, and factors associated with ipsilateral TP after left-sided LDN.

Materials and Methods

Surgical technique

All surgeries were performed by a single, highly experienced surgeon with over 1000 donor nephrectomies, utilizing an LDN with a Gel-POINT^TM platform (Applied Medical, Rancho Santa Margarita, CA, USA). The surgical technique has been described in detail previously. ^16,17 Briefly, the gonadal vein (GV) was ligated either at the renal confluence (level 1) or at or below the crossing of the iliac vessels (CIV) (level 2) (Fig. 1). Patients were allocated to either level 1 or level 2 groups in an alternating manner. Ureteral ligation (UL) was performed below the pelvic brim, and periureteral tissue was preserved during ureteral dissection.

OPEN IN VIEWER

FIG. 1.

Ligation of the gonadal vein at the renal confluence (level 1, image a) and at or below the crossing of the iliac vessels (level 2, image b) is indicated by the white arrows.

Results

The mean follow-up duration was 21.9 ± 15.6 months. Of the 61 male donors, 33 (54.1%) developed ipsilateral TP postoperatively. Table 1 shows the patient demographics, perioperative results, and sonographic conclusions according to the occurrence of ipsilateral TP and the location of GVL. There were no statistically significant differences in patient demographics between the analysis groups. The incidence of TP was 45.5% (15/33) in level 1 patients and 64.3% (18/28) in level 2, showing a higher tendency but no statistically significant difference (p = 0.141).

The ultrasound results showed that varicocele occurred in 20 out of 61 patients (32.8%) and hydrocele in 21 (34.4%). Of these, eight patients (13%) had both varicocele and hydrocele. Varicocele and hydrocele occurred in 9 patients (27.3%) and 11 patients (33.3%) in group 1 and 11 patients (39.3%) and 10 patients (35.7%) in group 2, respectively, with no statistical significance (p = 0.319 and p = 0.845). Varicocele was more frequent in level 1 patients (39.4%) compared with level 2 (25.0%), although the difference was not statistically significant (p = 0.233). While statistical significance was not established, varicocele was more prevalent in patients without TP and those who underwent level 1 GVL. Conversely, hydrocele was more common in level 2 patients (42.9%) than level 1 (27.3%), but again, without statistical significance (p = 0.202). No statistically significant differences were found in other ultrasound findings across the subgroups.

Table 2 presents an analysis of the TP characteristics based on the GVL level and the presence or absence of varicocele. The onset of TP was 11.2 ± 10.7 days, and it occurred within 1 week in 60.6% (20/33) of the cases. The average total duration of TP was 103.0 ± 114.1 days, and 63.7% were improved within 3 months. Pain duration tended to be longer in level 2 patients. In 75.8% of patients, pain was mild and resolved spontaneously. Surgical intervention was not required in any patient. Antibiotics and nonsteroidal inflammatory drugs were administered to four patients with epididymitis (4/33, 12%). There was no significant difference in the onset, duration, duration interval, persistency, and pain intensity according to the GVL level or presence or absence of varicocele.

Three patients with persistent TP (lasting >6 months) underwent ultrasound. One (level 1, mild pain) initially had varicocele, a small hydrocele, and epididymal cysts, but these had resolved on the follow-up ultrasound at 1 year. Both level 2 patients had small hydroceles (one with persistent moderate pain for >6 months).

Eight patients had moderate TP. Two had normal ultrasounds (pain duration: 30 and 45 days), two had hydroceles (pain duration: 45 days and ongoing), and four had varicoceles. Of the four varicocele cases, varicocele persisted in one (pain duration: 1 month), improved in one (pain duration: 150 days), and resolved in two (pain duration: 120 and 30 days). While not statistically significant, moderate TP seemed more frequent in patients with varicocele or level 1. Follow-up ultrasound in five patients with varicocele (no TP) showed persistence in two and resolution in three.

Discussion

While complications associated with laparoscopic renal operation and LDN are well-documented, research on TP after LDN remains scarce. Previous studies omitted TP or reported low incidence rates (1%–3%). ^{4 –6} However, recent studies suggested a wider range (6.2%–55%). ^{7 –15} Our study identified a particularly high incidence rate (54.1%). Compared with previous studies, the incidence rate of TP in retrospective studies tended to be lower (9.6% and 6.2%). ^7,9 However, recent retrospective studies using direct questioning methods (telephone or postal questionnaires) showed higher incidence rates of 31.9% and 38%, despite recall bias. ^13,15

Prospective studies consistently showed higher rates of TP ranging from 14.3% to 55%. ^{8,10 –12,14} One study reported that the level of GVL or UL might influence TP incidence. ¹¹ A subsequent study based on these findings reported a TP incidence rate of 14.4% after left-sided LDN. ¹² However, when GV and ureter ligation were performed above the CIV, the TP incidence rate was only 2.5% (1/40, level 1). Conversely, performing these procedures at or below the CIV resulted in a much higher rate of 30% (9/30, level 2). Gjertson and coworkers and Jalali and associates reported even steeper increases, with TP rates of 55% (11/20) and 40% (10/25) in LDN, respectively. ^8,10 Considerable variability exists in TP incidence rates across prospective studies, and even within the same study, LDN cases often exhibit higher rates. These inconsistencies are likely attributed to the incomplete understanding of TP’s underlying mechanisms and the influence of various factors, including surgical techniques and study designs.

Previous studies have proposed two main hypotheses for the etiology of TP. ^7,8 Kim and colleagues noted that TP could result from damage to the scrotal and spermatic branches of the ilioinguinal and genitofemoral nerves located near the gonadal vessel and ureter and recommended preserving the GV or ligating it at a higher level to minimize nerve damage during LDN. ⁷ Gjertson and associates hypothesized that venous congestion caused by the ligation and dissection of the GV could contribute to TP. ⁸ Their study demonstrated a statistically significant association between GV preservation and TP incidence (GV sacrificed vs. GV preserved: 33% vs. 3.4%, p = 0.003).

While the etiology of TP is multifactorial, a study by Srivastava and coworkers ¹¹ proposed that vascular congestion caused by GVL and neural injury to the spermatic plexus due to collateral disruption during GVL and UL are the major contributing factors. The authors argued that GVL cannot be the sole cause since TP in varicocele patients is alleviated by high ligation. In addition, they pointed out that TP can occur in right-sided LDN, where the GV is typically preserved, suggesting a potential role for nerve fiber injury.

We conducted various analyses to identify the factors associated with TP occurrence. However, unlike some studies, ^11,12 we were unable to pinpoint definitive contributing factors. While some studies have shown significant differences in TP occurrence based on the GVL, ^11,12 others have reported high TP rates even when GVL was performed above the CIV. ^13,15 In addition, one study demonstrated the importance of GV preservation in TP development, ⁸ whereas another found no statistically significant difference in TP rates between right LDN with a preserved GV and left LDN with a sacrificed GV. ¹⁵ Most studies point to vascular, lymphatic, or neural damage during GVL or UL as the major culprit. However, the differing TP incidence rates likely stem from differences in study design, surgical techniques (particularly GVL and UL levels), the absence of control groups, and the absence of proper comparisons with right-sided LDN. We reviewed TP incidence rates, characteristics, study designs, and GVL/UL levels from previous studies to provide a comprehensive overview (Table 3).

While existing studies showed variations in TP incidence, they presented similar characteristics of TP. In our study, TP onset (mean 11.2 ± 10.7 days) primarily occurred within 1 postoperative week (60.6%) and resolved within 3 months (63.7%). Most studies demonstrated a similar pattern, with TP onset within 1 week. TP onset ranged from immediately postoperation to 1 month postoperation. In our study, the TP duration averaged at 103.0 ± 114.1 days. While the average duration of TP is typically within 1 month, a few studies have reported average durations of several months. This is attributed to persistent pain in some patients. The prevalence of mild TP in our study (75.8%) reflects the general trend of TP being predominantly mild.

Scrotal ultrasound was performed on all patients in the present study to observe changes in the testis after LDN and confirmed that the main outcomes, varicocele and hydrocele, were not related to the location of the GVL and did not differ in TP occurrence. Some previous studies also performed scrotal ultrasound, but it was only performed in some patients with persistent or moderate TP, or no specific reason was mentioned. ^{7,9,11 –15} While some studies have investigated testicular swelling and reduced testicular blood flow, not all patients underwent ultrasound, and these findings were not analyzed in relation to GVL level or TP incidence. ^9,11,13 In addition, no studies have examined the incidence of varicocele or hydrocele after LDN or their association with TP. Our study is the only one that performed scrotal ultrasound on all patients to understand the etiology of TP.

While we identified a higher incidence of TP than reported in previous studies, no statistically significant association was found between GVL location and TP occurrence. This finding may be because the ligation site of the ureter was the same (below the pelvic brim) in both groups (level 1 and level 2). Thus, the etiology of TP after LDN remains elusive and likely involves a complex interplay of factors. However, neural injury at or below the CIV emerges as a potential primary contributor. The prospective nature of our study was overshadowed by its small cohort size and absence of comparison with right LDN, where GV preservation is prevalent. Further research with larger cohorts, right-sided LDN comparisons, and standardized surgical techniques is warranted to elucidate the underlying mechanisms of TP. Our findings provide valuable insight for counseling potential LDN donors about this underreported complication.

Conclusion

While the exact cause of TP after LDN remains unclear, our findings suggest a higher incidence than previously reported. TP can be mild and resolve spontaneously but may persist in some cases and lead to varicocele or hydrocele in 30% of the patients. Our study highlights the importance of informing potential male donors about postoperative TP. Further research is necessary to improve our understanding of TP and optimize surgical techniques to minimize its occurrence.