Mini-mesh and Lichtenstein repair compared with a modified Kugel technique for femoral hernia: a randomised controlled trial

Abstract

Introduction

A modified Kugel patch is more expensive than ordinary mesh and demands a wide dissection of the preperitoneal space in femoral hernia repair. We therefore adopted a novel method using mini-mesh and a Lichtenstein repair. This study compared mini-mesh and Lichtenstein repair with a modified Kugel technique in patients with a primary unilateral femoral hernia.

Methods

Patients with unilateral femoral hernia were assigned randomly to undergo mini-mesh and Lichtenstein repair (M group) or modified Kugel repair (K group), followed-up at one week, three months, one year and two years. Demographics, hernia characteristics and operative outcomes of two groups were analysed.

Results

A total of 48 patients in the K group and 49 participants in the M group completed follow-up. The operation time for the M group (68.6 ± 13.4 minutes) was significantly shorter than that of the K group (80.6 ± 10.1 minutes; p=0.030). There was no significant difference between the two groups for chronic pain, foreign body feeling and quality of life, and no recurrence occurred.

Conclusions

Mini-mesh and Lichtenstein repairs have reasonable results in the patients with femoral hernia in this study, with a reduced operation time compared with a modified Kugel repair. The trial was registered with the Chinese Clinical Trials Registry: ChiCTR1900022264.

Introduction

More than 20 million abdominal wall hernias are repaired worldwide annually. Groin hernia is the most common type, accounting for about 70% of these hernias.^1,2 Approximately 2–4% of groin hernias are femoral hernias,³ with a high incidence of acute complications.⁴ Until the 1990s, McVay’s suture repair was always used for femoral hernia, but prosthetic repairs, such as the mesh-plug repair, Kugel and Prolene^® Hernia System approaches, are widely applied today.^5–8 Laparoscopic management including transabdominal preperitoneal repair (TAPP) and total extraperitoneal repair (TEP) have become popular in recent years.^8–10

We frequently employed a modified Kugel patch for femoral hernia repair, because it appeared to be safe and well tolerated by patients.¹¹ In our hospital, the modified Kugel patch is three times more expensive than ordinary mesh and demands a wide dissection of the preperitoneal space during surgery. We therefore adopted a novel treatment for femoral hernia, using a mini-mesh and Lichtenstein repair. An oval mesh of 2.0–3.0cm diameter covers the femoral ring and a mesh is placed under the external oblique aponeurosis using the Lichtenstein technique, which allows for a short operation time and low mesh price.

In this research, our team compared the results of mini-mesh and Lichtenstein repair with a modified Kugel technique in primary unilateral femoral hernia patients. The hypothesis was that mini-mesh and Lichtenstein repair for femoral hernia could reduce operation time in comparison with a modified Kugel technique.

Materials and methods

A single-centre double-blind prospective randomised trial was conducted in the First Affiliated Hospital of Zhengzhou University, Henan, China. Patients were operated on by one surgeon, who had performed 38 cases of modified Kugel repair and 35 cases of mini-mesh and Lichtenstein repair for femoral hernia prior to the trial.

Outcomes

The primary outcome was the difference in operation time between the mini-mesh and Lichtenstein repair (M group) and the modified Kugel repair (K group). The secondary outcomes included early and late postoperative pain scores, analgesia, return to physical activity, urinary retention, wound infection, seroma, femoral vein thrombosis, chronic pain, foreign body feeling, quality of life and recurrence. Pain was assessed by visual analogue scale (VAS, 0–10) and chronic pain was defined as pain (VAS ≥ 3) lasting at least three months postoperatively. Femoral vein thrombosis was identified by patient’s complaint, physical examination and ultrasonography. Quality of life was estimated using the Short-form General Survey (SF-36, 0–26). Recurrence was justified by patient complaint and physical examination, and ultrasonography if necessary.

Inclusion and exclusion criteria

Patients aged 18 years or older with a primary unilateral femoral hernia were eligible. Exclusion criteria were bilateral, recurrent or incarcerated hernia. Femoral hernia was diagnosed mostly by patient complaint and physical examination preoperatively. When the diagnose was uncertain, we employed ultrasonography for verification. In this study, patient characteristics included sex, age, body mass index (BMI), comorbid conditions and hernia site (Table 1).

Table 1.

Demographics and hernia characteristics.

Demographic	K group	M group
Patients (n)	48	49
Sex:
Female	44	39
Male	4	10
Age (years), mean ± SD	58.0 ± 17.5	63.0 ± 14.3
Body mass index (kg/m2), mean ± SD	24.1 ± 2.7	24.2 ± 3.2
Comorbid conditions
Tobacco use	0	1
Hypertension	3	4
Coronary heart disease	1	1
Cerebral infarction	1	2
Chronic obstructive pulmonary disease	1	0
Diabetes	1	0
Site
Right	30	29
Left	18	20
Size of hernia sac, cm*	3.8 ± 0.8	3.8 ± 1.2

Randomisation and blinding

Patients were allocated to groups by randomisation performed by the online software at www.randomization.com. A researcher concealed randomisation by sealed envelopes and did not take part in clinical process of this study. Before the surgeon incised transversalis fascia during operation, the researcher opened the sealed envelopes to determine which technique was to be used. The investigators assessing the status of patients in the outpatient clinic and the patients themselves were blinded to the group in which they enrolled.

Follow-up

Participants and investigators were both blinded to the groups during postoperative assessments. Patients filled in the pain score form one week after surgery and follow-up was at three months, one year and two years postoperatively. In the outpatient clinic, patients were assessed for outcomes including chronic pain, foreign body feeling, quality of life and recurrence. Two residents performed the investigations.

Operative procedure

Operations were performed under general or local anaesthesia. We incised the skin, subcutaneous tissue, external oblique aponeurosis and transversalis fascia, then the preperitoneal space was accessible. The hernia sac was reduced completely from the femoral canal and the femoral ring was exposed clearly. In the M group, an oval mesh 2.0–3.0cm diameter was prepared according to the size of the femoral ring, cut from a 7.5 × 15.0cm mesh (Optilene^® 60g/m²; Braun, Barcelona, Spain). The lower edge of the mini-mesh was secured to the Cooper’s ligament with 2/0 polypropylene suture and the upper edge was fixed at the inguinal ligament using two sutures. The transversalis fascia was then restored with continuous 2/0 polypropylene suture. Finally, the 7.5 × 15.0cm mesh was clipped and placed under the external oblique aponeurosis using the Lichtenstein technique. In the K group, the preperitoneal space was dissected according to the following landmarks: medially, the pubic tubercle; laterally, the iliac vessels; and caudally, Cooper’s ligament. The oval mesh of modified Kugel patch (diameter 7.6cm; Bard^®, Bard-Davol, Warwick, United States) was inserted into the preperitoneal space, covering the entire groin region, including the direct, indirect and femoral spaces. We fixed the oval patch at Cooper’s ligament, inguinal ligament and the distal flap of transversalis fascia with 2/0 polypropylene sutures.¹¹ The transversalis fascia was closed and the plain polypropylene mesh included in the modified Kugel patch set was spread under the external oblique aponeurosis using the Lichtenstein technique. Ultimately, the external oblique aponeurosis, subcutaneous tissue and skin were sutured. The surgical procedure is shown in Figure 1.

Figure 1.

Surgical procedure. (A) The skin incision. (B) Femoral ring before mesh placement. (C) Mini-mesh secured to cover the femoral ring. (D) modified Kugel oval patch fixed to cover the groin region. (E) Lichtenstein repair (FR, femoral ring; FV, femoral vein; CL, Cooper’s ligament; IL, inguinal ligament; pps, preperitoneal space; dTF, distal flap of transversalis fascia; pTF, proximal flap of transversalis fascia; PT, pubic tubercle; SIAS, spina iliaca anterior superior.

Sample size calculation and statistical analysis

The sample size was calculated on the assumption that there would be a 30% reduction in operation time for the mini-mesh and Lichtenstein repair, from the pilot study, with a confidence interval of 95%, power of 80% and dropout rate of 10%; the minimal number of included patients was 96. Data were analysed with SPSS version 19.0. For numerical variables, we used independent samples t test or the Mann–Whitney U test, and for categorical variables Pearson’s chi-squared test or Fisher exact test. A p-value less than 0.05 was considered statistically significant.

Ethics

All participants enrolled in the study received oral and written information about the trial and signed informed consent before operation. The study was approved by Ethics Review Committee of the First Affiliated Hospital of Zhengzhou University, Henan, China. The trial was registered with the Chinese Clinical Trials Registry: ChiCTR1900022264.

Results

A total of 105 patients with femoral hernia were assessed for eligibility from July 2011 to December 2016. Six participants were excluded from the trial. The main reasons were patients withdrawing consent (n=2), preferred laparoscopic approach (n=3) and declined operative treatment (n=1). Thus, 99 patients were finally included; 49 were randomised to the K group and 50 were in the M group. Among these patients, one participant in the K group and one in the M group were lost to follow-up. Two years postoperatively, 48 patients were analysed in the K group and 49 in the M group (Fig 2).

Figure 2.

CONSORT diagram.

Demographics and hernia characteristics

The mean age of patients in the K group was 58.0 ± 17.5 years and 63.0 ± 14.3 years for the M group. Demographics and hernia characteristics were comparable between the two groups (Table 1).

Operative outcomes

In the K group, 5/48 patients underwent local anaesthesia, and 3/49 participants in the M group, with no significant difference. The operation time of the M group (68.6 ± 13.4 minutes) was significantly shorter than that of the K group (80.6 ± 10.1 minutes; p=0.030). In the K group, two patients had analgesia after surgery but none was needed in the M group, with no significant difference between the groups (p=0.091). In this trial, no significant difference was found in wound pain, return to physical activity and urinary retention, and no patient had wound infection, seroma or femoral vein thrombosis at one week postoperatively. One patient in the K group and one in the M group had chronic pain at two years follow-up, with no significant difference between the groups. At follow-up, SF-36 scores of two groups were improved from three months to two years. There was no significant difference regarding foreign body feeling and quality of life during the whole follow-up and no recurrence occurred (Table 2).

Table 2.

Operative outcomes.

Outcome	K group (n=48)	M group (n=49)	p-value
Type of anaesthesia (n):
Local	5	3	0.689
General	43	46
Operation time (minutes), mean ± SD	80.6 ± 10.1	68.6 ± 13.4	0.030a
Analgesic used (n)	2	0	0.091
Return to physical activity, days, mean ± SD	6.5 ± 0.7	6.8 ± 1.2	0.447
Urinary retention (n)	1	1	0.988
Wound infection (n)	0	0	–
1 week (n):
Wound pain at rest, VAS (median)	0.47	0.39	0.702
Wound pain on cough, VAS (median)	0.67	0.78	0.658
3 months (n):
Chronic pain	3	2	0.981
Foreign body feeling	3	1	0.595
Quality of life, SF-36, mean ± SD	22.4 ± 1.7	22.9 ± 1.2	0.447
1 year (n):
Chronic pain	2	1	0.986
Foreign body feeling	2	1	0.986
Quality of life, SF-36, mean ± SD	23.0 ± 2.0	23.6 ± 1.2	0.424
2 years (n):
Chronic pain	1	1	0.988
Foreign body feeling	2	1	0.986
Quality of life, SF-36, mean ± SD	23.8 ±1.6	23.9 ± 1.4	0.880
Recurrence	0	0	–

^a Statistically significant result.

VAS, visual analogue scale; SF-36, 36-item Short-form General Survey.

Discussion

A femoral hernia involves the protrusion of peritoneum, which may contain preperitoneal adipose tissue, abdominal or pelvic content through the femoral ring into the femoral canal inferior to inguinal ligament.^12,13 Recently, laparoscopic repair for femoral hernia has been widely used, as this method has some advantages. First, some femoral hernia patients have associated hernias which can be diagnosed and repaired with laparoscopic approach easily. Second, for patients who have undergone a previous open hernia repair, surgeons always choose laparoscopic management. However, the high cost and requirement for general anaesthesia are drawbacks for laparoscopic repair.¹⁴ Classically, three approaches are described for open femoral hernia repair: Lockwood’s infrainguinal approach, Lotheissen’s transinguinal approach and McEvedy’s high approach.¹⁵ Approximately nine years ago, we started to use mini-mesh and Lichtenstein repair using the transinguinal approach. In this study, we compare the outcomes of mini-mesh and Lichtenstein repair with modified Kugel repair to assess the safety and feasibility of mini-mesh and Lichtenstein repair for primary femoral hernias.

In our study, five patients in the K group and three in the M group had local anaesthesia, with no significant differences. Using local anaesthesia, we could operate on high-risk patients. Meanwhile, the patient’s preference was taken into consideration for the choice of anaesthesia.

Operation time for the M group was significantly shorter than in the K group in this study. In Ceriani’s research, 26 femoral hernia patients were treated using the plug technique and 24 were operated on using the Kugel patch. They reported that the operation time of plug group was significantly longer than that of Kugel group.¹⁶ Nevertheless, Chen stated no significant difference in operation time, comparing the Kugel approach (n=45) with the plug technique (n=40) for femoral hernia.¹⁷ In our trial, the oval modified Kugel patch demanded a wider dissection of preperitoneal space to unroll it. However, a mini-mesh was secured to Cooper’s ligament and inguinal ligament, covering the femoral ring only. These factors might be the reasons for a shorter operation time for the M group. According to health economics, a shorter surgery duration could lead to better use of operating room and shorter waiting time for operation.¹⁸ Furthermore, the modified Kugel patch is about £430 and £140 for ordinary mesh in our hospital. Therefore, compared with modified Kugel repair, mini-mesh repair has advantages for cost effectiveness.

At one week follow-up, two patients in the K group needed analgesics, while none in the M group did so, with no significant difference. No difference was found in wound pain, return to physical activity or urinary retention in this trial. In Ceriani’s study, the plug group presented a higher rate of early postoperative pain and a significant delay of the return to physical activity, compared with the Kugel group.¹⁶ Kulacoglu applied the mini-mesh tension-free repair in eight femoral hernias. During surgery, a round or oval patch 1.5–2.5cm in diameter was prepared to cover the femoral ring and the inguinal floor was restored with continuous two- or four-layer suture lines, as in the Shouldice technique, different from our study. Patient satisfaction was very good in seven cases, but one patient complained of mild pain for two weeks postoperatively.¹⁹

In our study, wound infection, seroma and femoral vein thrombosis did not occur in either group. In Chen’s research, two patients suffered seroma in the Kugel group and eight in the plug group, with a significant difference.¹⁷ Kulacoglu found a limited ecchymosis, but no surgical site infection.¹⁹ In Garg’s trial, laparoscopic total extraperitoneal repair was performed in six patients with femoral hernia and no one had wound infection or seroma formation in postoperative period.¹⁴ During surgery in the M group in our study, adipose tissue around femoral ring, which can protect femoral vein from the mesh edge, was not cleaned up. Consequently, compression of femoral vein and thrombosis were prevented.

In our series, no recurrence occurred at follow-up. In Chen’s research, there was no recurrence in the Kugel group, but four recurrences occurred in the plug group, a significant difference.¹⁷ In accordance with our study, no recurrence was observed in Ceriani’s, Kulacoglu’s or Garg’s trials.^14,16,19 Applying the Lichtenstein technique after mini-mesh placement might be related to the low recurrence rate in our study. It is known that inguinal incision may decrease the strength of the groin region, especially for the elderly, women and patients who are obese.

In this study, one patient in the K group and one in the M group suffered chronic pain at two years follow-up, with no significant difference. In Ceriani’s cohort, pain score at six months in the Kugel group was significantly lower than that in plug group.¹⁶ Nevertheless, no patient had chronic pain in Kulacoglu’s study.¹⁹ Chronic pain is multifactorial, as the type of mesh, operation skills, nerve injury and fixation method can affect its pathogenetic mechanism.^20,21 In this trial, the type of mesh changed in different group, but other factors were the same. In addition, we presented two patients in the K group and one in the M group had foreign body feeling, without a significant difference. Chen stated that no patient complained of foreign body sensation in the Kugel group, while six had the sensation in the plug group, a significant difference.¹⁷ It is reported that the placement of mesh can lead to foreign body reaction, which is material dependent. In our study, the meshes used in both groups were made of polypropylene.

Admittedly, our research has some limitations. First, the sample size is small and two years of follow-up may be insufficient to assess the outcomes. Second, although a strict quality control was applied in this trial, it cannot avoid bias completely as it is a single-centre study. Furthermore, recurrence may be asymptomatic and only can be detected by ultrasound examination.

Conclusions

The operative outcomes of mini-mesh and Lichtenstein repair are comparable to modified Kugel repair, with a reduced operation time for patients with femoral hernia. Our results are based on small patient numbers, and large-scale trials with long-term follow-up are essential to further evaluate the postoperative outcomes such as hernia recurrence and chronic pain. Mini-mesh and Lichtenstein repair is a safe and promising technique and can be considered as a feasible alternative for the treatment of femoral hernia.