Short Term Outcomes of Laparoscopic Totally Extraperitoneal Repair of Uncomplicated Groin Hernia Using Polyester Anatomical Mesh Without Fixation

Background: Totally extraperitoneal (TEP) repair of groin hernia can be performed with or without mesh fixation. Fixation can result in postoperative pain or paresthesia due to nerve entrapment. Compared to polypropylene mesh, polyester anatomical mesh (Parietex, Covidien, Mansfield, MA, USA) has a special configuration to fit the posterior inguinal anatomy. Also, the polyester-based chemistry and the rapidly absorbable biological coating increase the hydrophilicity of the mesh, which is thought to result in a fast and intimate tissue ingrowth that may obviate the need for fixation. Patients and Methods: Laparoscopic TEP repair using Parietex anatomical mesh without fixation was performed for 60 patients presenting with 63 uncomplicated groin hernias. Results: All patients were males with a mean age of 44.7±14.75 years. There were 60 (95.3%) primary, 3 (5%) bilateral inguinal and 2 (3.3%) femoral hernias. The mean operative time was 64.8±22.6 minutes. There were no major operative complications or conversions to transabdominal preperitoneal or open repair. In the early postoperative period, 54 patients (90%) had mild or no pain. Nine patients (15%) developed minor postoperative complications. The mean length of hospital stay was 1.1±0.3 days and the mean time of return to normal daily activities and to work was 2.6±0.64 and 7.15±1.13 days respectively. No patient developed chronic groin pain, mesh-related complications or recurrences during the study period. Ninety one percent of patients described their satisfaction with surgery as good or excellent. Conclusion: laparoscopic TEP repair of uncomplicated groin hernia using Parietex anatomical mesh without fixation is safe and does not increase the risk of hernia recurrence.


Introduction
Inguinal hernia repair is one of the most frequently performed operations in general surgery [1]. Operative techniques have evolved continuously over the past decades establishing tension-free mesh repair as the standard of care [2]. These techniques can be performed via open or laparoscopic surgery [3][4].
Laparoscopic mesh repair of inguinal hernia, compared with conventional hernia repair, provides very promising outcomes. It has all the advantages of preperitoneal repair and minimally invasive surgery with comparable results in terms of recurrence [5][6][7][8]. There are two standardized techniques of laparoscopic inguinal hernia repair: transabdominal preperitoneal repair (TAPP) described by Arregui in 1992 and totally extraperitoneal repair (TEP) described by Mc Kernan and Laws in 1993 [9,10].
TEP is a technically difficult procedure to learn and requires the surgeon to be familiar with the posterior groin anatomy, but, it has the advantage of direct access to posterior defects and non-violation of peritoneal cavity [11]. TEP is performed with or without fixation of the prosthesis. Fixation can result in postoperative pain, neuralgias, or paresthesia due to nerve entrapment or injury to the abdominal musculature [12].
Compared to conventional polypropylene (PP) mesh, polyester anatomical mesh (Parietex ® , Covidien, Mansfield, MA, USA) provides larger porosities and an increased softness, while the handleability of the product remains compatible with a laparoscopic placement. Moreover, polyester anatomical mesh has a special configuration to fit the posterior inguinal anatomy. Also, the polyester-based chemistry and the rapidly absorbable biological coating increase the hydrophilicity of the mesh, which is thought to result in a fast and intimate tissue ingrowth that may obviate the need for routine fixation of the mesh [13]. The aim of this study was to assess the short term clinical outcomes of using polyester anatomical mesh (Paritex ® ) in TEP repair of uncomplicated groin hernia without fixation and to compare the obtained results to those published in the literature.

Study Design
This study was conducted on 60 patients with 63 groin hernias admitted to Gastrointestinal and Laparoscopic Surgery Unit, General Surgery Department, Tanta University, Egypt during the period from January 2015 to December 2016. The operations were performed by surgeons experienced in laparoscopic surgery. Adult patients with uncomplicated groin hernia were included in the study. Complicated hernia, recurrent hernia after open posterior or laparoscopic repair, complete indirect inguinal hernia (inguinoscrotal) and patients with prior extensive lower abdominal surgery were excluded from the study. Primary end-points were the postoperative pain and hernia recurrence and secondary end-points were the postoperative complications and patients' satisfaction. The study protocol was approved by the "Research Ethics Committee" of the Faculty of Medicine, Tanta University and informed consent was collected from every patient before enrollment in the study.

Surgical Technique
The operating surgeon stands opposite the side of hernia, the camera holder beside him towards the head of the patient and the laparoscopic tower at the patient feet on the side of hernia. The preperitoneal space is accessed through a 10-15 mm transverse skin incision placed 1 cm below and lateral to the umbilicus on the side of hernia. The table is positioned in mild Trendelenburg position and slightly tilted towards the surgeon. A 10 mm 0 o telescope is inserted and used to open the preperitoneal space until the pubic bone, then replaced by a 30 o one. Two 5 mm ports are inserted in the midline; one about 1 cm above the symphysis pubis and the 2 nd midway between the other two ports. Dissection starts by opening the retropubic space of Retzius followed by the medial space exposing any direct, femoral or obturator hernia. The lateral space is then dissected till the anterior superior iliac spine by passing between the inferior epigastric vessels and indirect hernia sac. Indirect sac is dissected off the internal ring and cord structure, then, either reduced completely or ligated at its neck and divided distal to the ligature leaving the distal part of the sac in situ. A 15 x 10 cm Parietex ® anatomical mesh [ Figure 1] is introduced through the 10 mm port and unfolded in the space to cover the entire myopectineal orifice (MPO). No mesh fixation was used. The mesh is maintained in place by 2 graspers and gas released. Ports and telescope are removed and wounds closed. Patients were discharged home when they were independently mobile, self-caring, tolerating oral fluid, comfortable on oral analgesia and with no complications requiring hospital treatment.

Follow-up
Follow-up visits included the initial visit 10 days after surgery, then, regular follow-up visits at 1, 3 and 6 months after surgery. During these visits any complications or recurrences were recorded. The time needed to return to normal daily activities and work was recorded. Patients' satisfaction was checked at 3 months after surgery.

Data Collection
Operative data including operative time, complications or conversion were recorded. Postoperative pain severity was assessed using the Numerical Rating Scale (NRS) at 24 h, 10 days and 3 months following the procedure (patients were asked to rate the severest experienced pain whether this was on lying down, standing or ambulating). Post-operative morbidities and duration of hospital stay were recorded.

Statistical Analysis
Data were tabulated and analyzed using IBM SPSS Statistics software package version 20. Metric data were presented as mean and standard deviation, ordinal data were presented as range and median while nominal data were expressed as percentage. X 2 test was used to compare ordinal data. A P value of less than 0.05 was considered statistically significant.

Operative Findings
The operative time varied between 32 and 110 minutes with a mean of 64.8±12.6. Most patients with unilateral hernias (n=51/60; 85%) were operated up on within 90 minutes. There were no conversions to TAPP or open repair and there were no major operative complications. Bleeding from a small tributary of inferior epigastric vein occurred in 1 patient (n=1/60; 1.6%) and was controlled by compression. In another patient (1.6%) there was oozing that required insertion of a vacuum drain for 18 hours.
One patient (1.6%) developed surgical emphysema which resolved spontaneously without complications in 12 hours. Small hematomas were observed in 2 patients (3.2%) at the umbilical port and small fluid collections at the groin in 6 patients (10%) and all resolved spontaneously during the 1 st post-operative week. Superficial port sites infection occurred in 2 patients (10%) and it responded rapidly to treatment. No testicular complication, mesh-related complications or recurrences were recorded during the follow-up period.
Time needed to return to normal day to day activities varied between 1-4 days with a mean of 2.6±0.64 days. Eighty percent of patients resumed normal daily activities within 3 days.  Assessment of the time of return to work, however, was difficult because 12 patients (20%) had sick leaves and 9 patients (15%) were unemployed. In the remaining 39 working patients (39/60; 65%), the time needed to return to work varied between 5-11 days with a mean of 7.15±1.13 days. Table 3 At the postoperative day 7, 27 patients (27/39; 69.2%) returned to work and at postoperative day 9, 36 patients (36/39; 92.3%) were able to return to work. Only 54 patients (90%) were available for follow-up at 3 rd postoperative months and 39 patients (65%) at 6 months postoperatively. When asked about the degree of satisfaction of their operations 3 month after surgery, 30 patients (n=30/54; 55.5%) described it as excellent, 19 patients (19/54; 35.2%) described it as good and 5 patients (9.2%) described it as fair.

Discussion
The introduction of minimal access surgery in the field of groin hernia has established a redefinition of the end points of an acceptable repair including patient's satisfaction, cost and cosmesis, in addition to the classic outcome measures, namely groin pain and recurrence [6].
In spite of markedly reducing recurrence rates, prosthetic materials are often linked to several complications including chronic groin pain and foreign body sensation resulting in reduced quality of life [14,15]. It was noted that the choice of the mesh is far more important than the surgical technique as a determinant of the outcome of inguinal hernia repair [16,17].
One potential advantage of polyester is its light weight [18] which may lead to less long-term scaring and, subsequently, less long-term pain. Another advantage of polyester is its softness without loss of memory making laparoscopic placement easier which may help shorten the learning curve and operative time [19]. The findings in this study showed that using polyester anatomical mesh (Paritex®) in laparoscopic TEP repair of uncomplicated groin hernia without fixation is safe, effective and associated with minimal postoperative pain, early return to normal daily and work activities with high patients' satisfaction rate. Also, no mesh-related complications, chronic groin pain or recurrence were recorded during the follow-up period In this study, a 15x10 cm polyester anatomical (Parietex®) mesh was used with no recorded complications related the type of mesh. On contrary, we touched some of the advantages of this prosthesis. Firstly the 3-D anatomical design of the mesh provided good configuration with the inguinal region making its fixation unnecessary. Secondly, handling of the mesh during laparoscopy was excellent (compared to our previous experience with PP mesh) as it was both soft while maintaining its memory. Finally, no patient suffered from foreign body sensation, stiffness or chronic groin pain which may be attributed to the mesh. These results seem to compare well with those of several other studies [13,20].
There was no recurrence in this study. This outcome, however, should be interpreted with caution due both to the small sample size and the relatively short follow-up. With the use of mesh, the incidence of hernia recurrence is considerably low [21]. Possible causes of recurrence include using a small sized mesh [22] and displacement of the mesh during desufflation [23]. Strategies to prevent recurrence include using a mesh size 10x15 cm and supporting the medial edge of the mesh during desufflation [23]. Absence of early recurrence in this study suggests that, when these precautions are taken, non-fixation of the mesh does not increase recurrence rate when compared to fixation with regular methods.
Mesh fixation in laparoscopic groin hernia repair is currently a debatable issue. Inadequate mesh fixation has been reported by some authors to be a main cause of hernia recurrence after laparoscopic repair [24,25]. Although mesh fixation has been linked to an increased incidence of nerve injury and increased post-operative costs, many surgeons think that fixation is necessary to reduce the risk of hernia recurrence [26]. A randomized controlled trial of the early outcome of stapled vs unstapled techniques of laparoscopic TEP repair showed that unstapled repair scores are equivalent to their stapled counterparts with respect to recurrence and complications [27]. Absence of recurrence or chronic pain in this study is comparable to data from recent studies which suggest that mesh fixation in TEP repairs may be avoided without increasing the risk of hernia recurrence and at the same time avoiding neuropathic complications [23,28,29]. Besides, mesh non-fixation in an interesting study yielded an unaltered recurrence rate and costs $500 less [23]. Fixation is, therefore, more expensive than non-fixation [30]. Fortelny reported that fixation and non-fixation of the mesh in TEP repair are associated with equal risk of post-operative pain or recurrence and recommended that non fixation has to be considered in all types of inguinal hernias except large direct defects [31].
Evaluation of postoperative pain in this study showed that most of the patients (n=54; 90%) had mild or no pain in the 1 st postoperative day and at the 3 rd postoperative month, all patients were pain-free. No patient in this series experienced severe pain, visceral or neuropathic pain. These results are comparable to those reported in literature [7,32].
No patient developed chronic groin pain in this study. This outcome can be attributed to the type of mesh used and the policy of non-fixation of the mesh. After a mesh based inguinal hernia repair, 11% of the patients suffer from chronic pain, more than a quarter of these report moderate to severe pain [33]. There is some evidence that the development of chronic pain is influenced by the weight and quality of mesh used. Heavy-weight meshes are less well tolerated by the patients, while, light-weight meshes induce less inflammation and be more favorable in terms of pain reduction [34]. In a meta-analysis by Sajid et al., the authors reported that the incidence of chronic groin pain is significantly reduced after light-weight implantation [35]. Moreover, several studies reported that the risk of acute and chronic pain after stapled mesh fixation is higher compared with fibrin fixation or non-fixation [36,37]. These studies add more evidence in favors of the anatomical configuration of Parietex® anatomical mesh which doesn't need fixation.
In the present study, the mean operative time in unilateral hernia was 64.8 ± 22.6 minutes; a result that didn't differ significantly from that published in literature. There is considerable agreement among laparoscopic surgeons that the learning curve for the laparoscopic TEP is significantly steep [38]. In a systematic review, McCormack et al reported that the mean operative time by surgeons who performed less than 20 TEPs was 95 minutes, while mean operative time by surgeons who performed 30-100 TEPs was 55 minutes [39].
The mean length of hospital stay in the present study was 1.1 ± 0.31. Ninety percent of patients stayed one day and 10% stayed 2 days. These results agree with those of previous studies [40,41]. One more study showed also that the length of hospital stay and time needed to resume normal activities were found significantly higher after TEP hernia repair when mesh fixation was used compared to nonfixation [42].
In this study, the mean time needed to return to normal daily activities was 2.6± 0.94 days and 48 patients (80%) resumed normal daily activity during the first three post-operative days. These results are supported by several previous studies including systematic reviews which showed that laparoscopic TEP repair is associated with fast return to normal daily activities. [33,43]. Besides, a retrospective study on 1,692 laparoscopic TEP without fixation of the mesh showed that non fixation of the mesh is associated with a short hospital stay and early resumption of normal work [28].
The mean duration needed to return to work in this study was 7.15±1.63 days. These results are not only comparable to previous studies that confirm early return to work after laparoscopic TEP repair but also are superior to some of them. Kouhia reported the mean return to work after TEP as 14.8 days [41] while, Pawanindra et al. reported it as 12.8 days [44].
About 91% of patients in this study (n=49/54; 90.7%) described their satisfaction with the operation 3 months after surgery as good or excellent. These results are comparable to several previous studies which showed high patient satisfaction scores following TEP [32,40,45].
There were no hernia recurrence in any of the studied patients during the follow up periods; a result that agrees with many similar studies [41,42].
Indeed this study suffers some limitations. The small sample size, the short duration of follow-up and the absence of a control group are the main limitations of this study.

Conclusion
Using Parietex® anatomical mesh in laparoscopic TEP repair of uncomplicated groin hernia without fixation is safe with no increased risk of recurrence. The physical properties of this prosthesis facilitate its laparoscopic handling making it a better alternative to conventional PP mesh. A further study on a larger number of patients with a longer follow-up is recommended to evaluate the late outcome of this procedure.

Conflict of Interest Statement
All the authors do not have any possible conflicts of interest.