Postoperative pain after laparoscopic percutaneous extraperitoneal closure for inguinal hernia in children: a single-center retrospective study

Abstract

Background

Chronic postoperative inguinal pain (CPIP) is a major complication after hernia repairs in adults. However, little is known about CPIP in children.

Methods

Charts of 855 children with an average age of 3.7 years (range, 0–18 years) who underwent laparoscopic percutaneous extraperitoneal closure (LPEC) between April 2016 and December 2023 were reviewed. Pain after one postoperative month (PIP: postoperative inguinal pain) was the primary outcome measure. Of these, pain lasting more than three months was extracted as CPIP.

Results

Nine children (1.1%, four males and five females) complained of PIP. All four males, having undergone LPEC before puberty, had temporary pain. Among four females with PIP, CPIP occurred in three (0.35%), who were effectively treated with psychiatric approaches in two and by a reoperation to release the round ligament in one.

Conclusions

CPIP was rare after LPEC in children. Adolescent females were at greater risk of CPIP than younger males. Round ligament pain was the cause in one case.

Trial registration

This study was approved by the institutional review board of Aichi Medical University (approval number: 2023 − 241).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-025-06392-z.

Background

Chronic postoperative inguinal pain (CPIP), defined as pain lasting more than 3 months following surgery [1], is a major complication after inguinal hernia repairs. In adults, CPIP occurs in 11% of cases after open repairs but only 6% of cases following laparoscopic approaches [2]. However, the incidence of CPIP occurring after herniorrhaphy in children and whether laparoscopic approaches decrease the incidence remain unknown. We retrospectively reviewed pediatric patients undergoing laparoscopic hernia repairs for postoperative pain.

Methods

Patients

The clinical records of 855 children under 19 years of age who underwent laparoscopic percutaneous extraperitoneal closure (LPEC) at our hospital between April 2016 and December 2023 were retrospectively analyzed in this study. Children were categorized into younger (0–8 years) and older (9–18 years) groups to compare pain before and after puberty, which brings many changes to the body including neurodevelopment and sex hormone-induced morphological changes in the groin. This study was approved by the institutional review board of Aichi Medical University (approval number: 2023 − 241).

Surgery

Single-incision LPEC was performed. A port and forceps were inserted from the umbilicus. An unabsorbable suture was placed around the internal inguinal ring using a 19-gauge LPEC needle (Hakko CO, Japan). In girls, the round ligament was ligated with the hernial sac. When the contralateral processus vaginalis was patent, it was also repaired during LPEC.

Anesthesia and analgesia

All cases received general anesthesia, with additional block anesthesia in some cases. During the operation, fentanyl and acetaminophen were administered for analgesia. Acetaminophen was administered for postoperative pain. In patients of the older group, loxoprofen was used if necessary.

Pain assessment

After 1 month or later, patients who revisited our hospital complaining of postoperative inguinal pain (PIP) were included in this study. Of these, pain lasting more than three months was extracted as CPIP. Pain intensity was assessed using verbal rating scale (VRS): 0, no pain; 1, mild pain; 2, moderate pain; 3, severe pain. There were three categories of pain: Temporary Pain, pain subsiding within a month; Psychological Pain, pain relieved by psychiatric management; and Ligament Pain, pain associated with the round ligament.

Statistics

The statistical analysis was performed using the Statistical Package for the Social Sciences version 27 (SPSS, Chicago, IL, USA) and Easy-R (EZR, Jichi Medical University, Japan). A Pearson Chi-squared test or Fisher exact test was used to compare categorical variables. The Bonferroni P-value adjustment method was applied. Continuous variables were compared using a t-test after a Levene test to assess homogeneity. In all analyses, p < 0.05 was regarded as statistically significant.

Results

Patient characteristics are listed in Table 1. Females were significantly older than males (p < 0.01). In total, 1323 hernias were repaired. The proportion of hernias at each location (right, left, bilateral) did not significantly differ between the sexes. The median postoperative observation period was 4.2 years (range, 0.7–8.3 years).

Table 1.

Patient characteristics

	Total n = 855	Male n = 476	Female n = 379	p-value
Age* (years)	3.74 ± 3.140	3.36 ± 3.048	4.23 ± 3.190	< 0.001
Symptomatic side**	421/323/111	256/173/47	165/150/64	0.001
LPEC side**	226/161/468	131/85/260	95/76/208	0.599

LPEC Laparoscopic percutaneous extraperitoneal closure

*Mean ± standard deviation

**Counts or right/left/bilateral cases

Nine patients (1.1%) complained of PIP (Table 2). The median time until pain occurrence was 4 months (range, 0–87 months). PIP occurred significantly more frequently in older-group females than in younger-group males and younger-group females (p = 0.0083 and p = 0.0017, respectively) (Table 3). Pain among male patients was all temporary and related to playing sports, postoperative stitch abscess, or testicular elevation.

Table 2.

Characteristics of patients suffered from postoperative pain

No.	Sex	Age at operation (y. o.)	Symptomatic side	Hernia side	Pain side	Post-operative months	Pain duration (months)	VRS	Pain category	Trigger	Intervention	Outcome	Observation period (months)
1	M	4	L	L	B R: open repair	86	< 1	2	Temporary	Basketball	Acetaminophen	Remission	89
2	M	4	L	B	R*	7	< 1	1	Temporary	After stitch abscess	No medication	Remission	23
3	M	5	L	L	L	4	< 1	1	Temporary	Kendo	No medication	Remission	23
4	M	7	L	B	R*	14	< 1	1	Temporary	Baseball Testicular elevation	No medication	Remission	26
5	F	7	R	R	R	0	8	2	Psychological	Constipation	Acetaminophen	Following	9
6	F	9	R	B	B*	9	3	2	Psychological	Constipation	Loxoprofen Psychiatric management	Remission	44
7	F	11	R	R	R	1	< 1	2	Temporary	-	Loxoprofen	Remission	41
8	F	14	B	B	B	1	29	3	Ligament	Menstruation	Releasing round ligaments by re-operation	Remission	72
9	F	15	L	L	L	1	< 1	2	Temporary	-	Loxoprofen	Remission	13

y.o Years old, M Male, F Female, VRS Verbal rating scale

*Pain after repair of contralateral patent process vaginalis

Table 3.

Comparing pain by sex, age, verbal rating scale and pain category

PIP Postoperative inguinal pain, CPIP Chronic postoperative inguinal pain

*p = 0.0083

**p = 0.0017

***p = 0.031

CPIP were observed in only three patients (0.35%), all females, lasting for 3–29 months. CPIP occurred significantly more frequently in older-group females than in younger-group males (p = 0.031) (Table 3). Pains in two of the three patients subsided with control of constipation and psychiatric treatment. When their psychological concerns were addressed during the interview with a psychiatrist, their physical pains were also alleviated. The remaining patient had worsening pain with menstruation, which was relieved by surgery releasing the ligaments (Fig. 1). The hernias have not recurred four years after re-operation.

Fig. 1.

Reoperation for ligament pain. a We confirmed no recurrence. b Previous sutures (arrowheads) were tightening the round ligaments. c The sutures were totally removed

Discussion

The present study showed that 1.1% of children complained of PIP, and 0.35% had CPIP. In the literature, 17 reports describe PIP for over 50 children [3–19] (Table 4). Persistent pain for 3 or more months or pain described as chronic, severe, or refractory were considered to reflect CPIP. Overall, the rate of CPIP after pediatric open and laparoscopic repairs was 7.7% and 0.4%, respectively, the incidence being lower than in adults. Laparoscopic herniorrhaphy decreased CPIP occurrence in children compared with open repairs, but it was not eliminated.

Table 4.

Reports of pediatric postoperative inguinal pain (PIP) after inguinal hernia repair

Year		Author	Country	Procedure	Age	Observation*	Patients	PIP		CPIP
					years, range	years	n	n	%	n	%
Open repairs
2007	Aasvang		Denmark	Open	0–4	16.8	651	-	-	88	13.5
2010	Zendejas		USA	Open	0–17	49.2	213	-	-	7	3.0
2012	Kristensen		Denmark	Open	0–12	3.2	98	17	17.0	7	7.1
2017	Mossetti		Italy	Open	0–16	0.5	87	31	36.0	13	15.0
2019	Nakashima		Japan	Open	0–14	3.8	3497	238	6.8	-	-
2021	Kurobe		Japan	Open	0–15	(1–11)	241	-	-	1	0.4
2021	Al-Taher		Jordan	Open	0–12	1.0	100	-	-	2	2.0
2023	Zhang		China	Open	0–14	0.2	136	6	4.4	-	-
2015	Gasior		USA	High ligation	12–19	1.5	210	-	-	14	6.7
2018	Cui		China	Lichtenstein	13–18	1.3	170	-	-	5	2.9
						Subtotal	5403	292/3818a	7.6	137/1770b	7.7
						Median			11.9		4.9
Laparoscopic repairs
2017	Geiger		Germany	Intra-corporeal	0–16	3.1	138	7	5.6	-	-
2017	Wang		China	LPEC	0–14	1.5	1464	-	-	0	0.0
2019	Nakashima		Japan	Laparoscopic	0–14	2.0	2057	116	5.6	-	-
2021	Kurobe		Japan	LPEC	0–15	(1–11)	329	-	-	1	0.3
2021	Duan		China	LPEC	0–15	1.1	2018	0	0.0	-	-
2021	Xu		China	LPEC	0–11	0.5	917	3	0.3	-	-
2021	Al-Taher		Jordan	Intra-corporeal	0–12	1.0	55	-	-	0	0.0
2023	Zhang		China	LPEC	0–14	0.2	234	0	0.0	-	-
2024	Wang		China	LPEC	0–15	-	60	-	-	0	0.0
2024	Xu		China	LPEC	0–12	1.5	219	-	-	3	1.3
Present study			Japan	LPEC	0–18	4.2	855	9	1.1	3	0.3
2018	Cui		China	TEP/TAPP	13–18	1.3	336	-	-	5	1.4
2023	Fan		China	LPEC	13–18	6.1	70	4	5.7	-	-
						Subtotal	8752	139/6289a	2.2	12/3318b	0.4
						Median			1.0		0.3
						Total	14,155	431/10,107a	4.3	149/5088b	2.9
						Median			5.6		1.4

n Sample size, PIP Postoperative inguinal pain, CPIP Chronic postoperative inguinal pain, LPEC Laparoscopic percutaneous extraperitoneal closure, TEP Total extraperitoneal repair, TAPP Transabdominal preperitoneal repair

^athe number of patients with PIP/numbers of patients with PIP data

^bthe number of patients with CPIP/numbers of patients with CPIP data

*Median, mean, or range

Our data also showed that adolescent girls are at higher risk of CPIP than younger boys. One reason is that psychological pain likely affects adolescent girls more than younger girls and boys, possibly the result of female hormones or greater psychological stressors [20]. The association between CPIP and mental illness, such as vulnerability, anxiety and depression, is an important aspect, as pointed out in the hernia guideline [1]. Several mechanisms have been proposed: neurological, neuroimmune, behavioral, psychological and environmental mechanisms [21]. In patients with psychiatric disorders, some kind of negative feedback appears to amplify subtle pain sensations. To break this negative cycle, the present study showed that psychological support was effective. Constipation could be associated with depression [22], which may be helpful in evaluating mental health. As with neuropathic pain, tricyclic antidepressants [23] and analogs of the neurotransmitter gamma-aminobutyric acid [1] may also be effective to remove pain from the object of interest.

Another contributing factor may be the round ligament, which becomes swollen after puberty. Round ligament pain is a new concept that has recently been recognized in cases of round ligament varicosities and ligations [24, 25]. In particular, pregnancy and menstruation may become pain triggers due to changes in the volume of the ligaments intermediated by estrogen and progesterone receptors [26]. When the round ligaments become thicker and shorter due to the influence of female hormones, the ligaments are compressed and pulled by the ligature, causing pain. Three studies report similar ligament pain after pediatric LPEC [8, 27, 28] (Table 5). The pain related to menstruation and continued until reoperation, similar to our case. Previous studies considered nerve involvement and performed neurectomy or ligament resection [8, 27, 28]. Ligation of the round ligament in LPEC can involve a genital branch of the genitofemoral nerve, which converges to the ligament at the internal inguinal ring. LPEC-induced neuralgia has also been reported in adults [17, 29]. However, the three reports above did not detect nerve involvement. In our case, the release of the ligament was sufficient to alleviate the pain. In the absence of neuropathic pain, neurectomies may not be necessary.

Table 5.

Previous reports of round ligament pain after LPEC

		Age	Pain duration	Menstrual relation	Intervention
		years	months
2019	Ishikawa	15	12	+	Ligament resection
2021	Kurobe	11	3	n. a.	Neurectomy and ligament resection
2022	Uchida	14	12	+	Neurectomy and ligament resection
Present study		14	29	+	Release of ligament

LPEC Laparoscopic percutaneous extraperitoneal closure, + Present, n.a Not available

This study had some limitations. Some cases with postoperative pain may have gone undetected because only patients who visited a hospital were identified for inclusion in this study. However, since our institution is a regional hospital, it is unlikely that patients visited another hospital.

Conclusions

In conclusion, this study showed that 1.1% of children experienced PIP and that 0.3% had CPIP. Female patients after prepuberty were at higher risk of CPIP than males and younger females, which may be attributed to psychiatric factors and round ligament growth after prepuberty.

Abbreviations

LPEC

Laparoscopic percutaneous extraperitoneal closure

PIP

Postoperative inguinal pain

CPIP

Chronic postoperative inguinal pain

TEP

Total extraperitoneal repair

TAPP

Transabdominal preperitoneal repair

Authors’ contributions

SK, KK, NM, and RK operated on the patients. SK and KK analyzed the patients’ data. YF and TS determined the surgical strategy. All authors have read and approved the final manuscript.

Funding

No funding was received for this study.

Data availability

The data supporting the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

Our study was conducted in accordance with the Declaration of Helsinki. The ethics committee of Aichi Medical University approved this study (2023 − 241). Informed consent to participate was obtained from all patients. For participants under the age of 16, informed consent was obtained from their parents or legal guardians prior to participation.

Consent for publication

The parents or legal guardians of any participant under the age of 18 provided consent for publication.

Competing interests

The authors declare no competing interests.