International Journal of Surgery 12 (2014) 1380e1384
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Original research
Standard polypropylene mesh vs lightweight mesh for Lichtenstein repair of primary inguinal hernia: A randomized controlled trial Zaza Demetrashvili a, b, *, Kakhi Khutsishvili b, Irakli Pipia b, Giorgi Kenchadze b, Eka Ekaladze c a b c
Department of Surgery of Tbilisi State Medical University, 33, Vazha-Pshavela ave., 0177 Tbilisi, Georgia Department of General Surgery of Kipshidze Central University Hospital, 29, Vazha-Pshavela ave., 0160 Tbilisi, Georgia Department of Biochemistry of Tbilisi State Medical University, 33, Vazha-Pshavela ave., 0177 Tbilisi, Georgia
h i g h l i g h t s During Lichtenstein with polypropylene mesh, the worst characteristics can be chronic pain. In order to prevent such kind of difficulties, the usage of lightweight mesh is recommended. The usage of the LW mesh was associated with less feeling of foreign body than that of the HW mesh. Thepoint listed above can be considered as an advantage of LW mesh rather than HW mesh.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 4 August 2014 Received in revised form 13 October 2014 Accepted 25 October 2014 Available online 28 October 2014
Purpose: The aim of the present clinical study was to compare early and late outcomes after inguinal hernia repair with the heavyweight mesh (HW) and lightweight mesh (LW) during a 3 year follow-up period. Methods: 226 patients were randomized into LW and HW mesh groups, both of which underwent unilateral primary inguinal hernia repair via the Lichtenstein technique. Wound complications (infection, hematoma, seroma), hernia recurrence, pain and feeling of foreign body in inguinal area were determined in patients. Pain was measured by visual analogue scale. Results: No statistical difference has been found between LW and HW groups by wound complication (P ¼ 0.80). One case of hernia recurrence has been mentioned in both groups one year after hernioplasty. But there was no detectable difference between the two groups. No significant difference has been found between LW and HW groups by frequency of chronic pain 7 days, 1 and 3 months, 1, 2, and 3 years after surgery. As for the feeling of foreign body in groin it is similar in both groups after 1 and 3 months. Level of feeling of foreign body was significantly lower in LW group 1, 2, and 3 years after surgery, than in HW group (P ¼ 0.03, P ¼ 0.02, P ¼ 0.02, respectively). Conclusion: Our research shows no significant difference in wound complications, hernia recurrence and chronic pain after Lichtenstein hernioplasty, by using of LW and HW meshes. The usage of the LW mesh was associated with less feeling of foreign body than that of the HW mesh, what can be considered as prevalence of LW mesh hernioplasty. © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
Keywords: Lightweight mesh Heavyweight mesh Lichtenstein Inguinal hernia
1. Introduction Inguinal hernia repair is one of the most frequently performed operations in general surgery. Tension-free mesh repair currently is the gold standard in inguinal hernia surgery. Currently the
* Corresponding author. Department of Surgery of Tbilisi State Medical University, 33, Vazha-Pshavela ave., 0177 Tbilisi, Georgia. E-mail addresses: [email protected] (Z. Demetrashvili), kkhutsishvili1972@ yahoo.com (K. Khutsishvili), [email protected] (I. Pipia), [email protected] (G. Kenchadze), [email protected] (E. Ekaladze). http://dx.doi.org/10.1016/j.ijsu.2014.10.025 1743-9191/© 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
Lichtenstein method is one of the most popular techniques [1]. Usage of prosthetic materials decreased the frequency of hernia recurrence, although the chronic pain and feeling of a foreign body in inguinal area after surgery is still considerable problem e it worsens the level of patients' quality of life [2e4]. The incidence of chronic pain after inguinal hernioplasty varies from 9 to 52% and the feeling of a foreign body occurs in around 40% of patients [3,5,6]. The pain may be caused by damage to the inguinal nerves, but these complications may be due to the foreign body reaction against the mesh which results in an inflammatory response and scar tissue formation [5,7]. The reaction on foreign
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384
body is depend on the type and volume, as well as the size of pores and web-structure of synthetic prosthesis. Taking into consideration this fact, nowadays partially absorbable lightweight meshes (LW) are being used instead of heavyweight polypropylene meshes (HW). Low mass, decreased content of foreign body and large pores are characteristic for LW [8e10]. According to the current researches usage of LW meshes for inguinal hernioplasty decreases the frequency of chronic pain [11e13], at the same time several articles don't confirm the fact [14,15]. It's worth mentioning, that the risk of hernia recurrence might be increased in case of using LW meshes [16]. The aim of the present clinical study was to compare early and late outcomes after inguinal hernia repair via the Lichtenstein technique with the heavyweight mesh (HW) and lightweight mesh (LW) during a 3 year follow-up period. 2. Methods From January 2008 to April 2011 patients over 18 years of age who underwent elective surgery for unilateral primary inguinal hernia via the Lichtenstein technique were enrolled in the study. The patients were operated at the General Surgery Department of Kiphshidze Central University Hospital. The inclusion criteria were a unilateral primary inguinal hernia requiring operative treatment and patient's approval to participate in the study. The exclusion criteria were bilateral hernia, irreducible hernia, recurrent hernia, strangulated hernia, a patient's preference for either mesh type, or a patient's refusal to participate in the study. The basic principle for this study was one unit, one surgeon trained in the standard Lichtenstein technique and the use of LW and HW meshes. The patients were assigned to one of the two groups: the LW group or the HW group. The randomization (by simple random sampling) of patients to each of the two groups described above was done before the surgical intervention. The assignment of patients to the specific groups was performed by the clinical manager not involved in the surgical procedures. The study participants were blinded regarding the type of the mesh used in the surgical intervention. The Lichtenstein hernioplasty was performed according to the original description of the technique [17]. The nerves in inguinal canal were identified and preserved when possible. In the HW group, a monofilament polypropylene mesh with a weight of 82 g/m2 and pore size 0.8 mm (Prolene, Ethicon, Somerville, New Jersey) was used. The LW mesh in this study was Ultrapro (Ultrapro, Ethicon, Somerville, New Jersey), a large pore composite mesh (polypropylene and poliglecaprone, Monocril) (weight ¼ 28 g/m2, pore size 3 mm). In both groups, 8 12 cm mesh was applied. Polypropylene 2/0 monofilament suture material was used for mesh implantation. Several preoperative factors were studied, which included sex, age, body mass index, occupation, tobacco use, risk groups by American Society of Anesthesiologists (ASA) and comorbidities, and site of hernia. Patients with ASA groups 4 and 5 were excluded from the study. Among the intraoperative factors, the following were evaluated: type of hernia, anesthesia method (local, general), and duration of the operation. Prophylactic antibiotics were not used in all patients. We were using it only in patients with concurrent disorders. In these instances, 1.5 g cefuroxime was used intravenously 30 min before the operation. Among the postoperative data, the following were studied: postoperative days at the ward (hospital stay), sick-leave days, and complications. The latter were divided into two groups: early and late complications. The early complications included wound infection, hematoma, and seroma. The late complications included chronic pain in the inguinal region, the feeling of a foreign body and
1381
hernia recurrence. Pain scores were measured on a Visual Analogue Scale (VAS), ranging from 0 (no pain) to 10 (worst imaginable pain). After discharge from the hospital, all patients were examined after 1 week, 15 days, and 1 month at the outpatient department by the same surgeon who performed the operation. Also, these patients were examined 3 month, 1, 2, and 3 years after the operation date. The examinations were performed by surgeons who had not been participating previously in this study. They were paying attention to the pain in the inguinal region, to the feeling of a foreign body and the presence of hernia recurrence. The pain questionnaire included questions regarding pain at rest, on coughing, while climbing steps and during physical activity. 3. Statistical methods Descriptive statistics methods were used to characterize each variable. Comparison of continuous variables was performed by independent samples t-test or the ManneWhitney U test according to the normality of the variables. Categorical variables were evaluated by two-tailed Chi-square test or Fisher's exact test where appropriate. The threshold for statistical significance was set to P < 0.05. Statistical tests were performed by SPSS 16.00 (SPSS Inc., Chicago, IL). 4. Results From January 2008 to April 2011, 328 patients underwent inguinal hernia repair via Lichtenstein technique. Among these patients, 226 were randomized in two groups equally (113 patients in each group). All of these patients underwent the allocated operations. Information about 28 patients was lost during the time observation: among them e 19 patients were not coming for examination, 7 patients were died during observation period (the causes of death were all non-hernia surgery related), in 2 patients developed recurrence of hernia. Subsequently 102 patients from HW group and 96 e from LW group were consecutively examined during 3 years after surgical operation. The data of this investigation is analyzed on this article (Fig. 1). Both groups were similar by preoperative (sex, age, body mass index, tobacco use, American Society of Anesthesiologists risk groups, comorbidities, site of hernia, and occupation) and intraoperative (type of hernia, anesthesia, prophylactic antibiotics, and operation time) factors. No statistically significant differences were found between the groups by these factors (Table 1, Table 2). Regarding the postoperative data, no statistical difference has been found (P ¼ 0.35) between groups by postoperative time spent at the ward (hospital stay), and by sick-leave days (P ¼ 0.15). In the LW group, 8 early complications (wound infection, hematoma, seroma) were observed (8.3%), in the HW group e 10 early complications (9.8%). The difference did not statistical significant (P ¼ 0.80). One case of hernia recurrence was marked in each group after 1 year of surgery. But there was no detectable difference between the two groups (Table 3). As for frequency of inguinal pain the difference was not statistically significant between LW and HW groups 7 days, 1 and 3 month and 1, 2 and 3 years after surgery. There was no detectable difference between the two groups according to average VAS scores too (Table 4). The difference was not statistically detectable between LW and HW groups concerning the feeling of a foreign body 7 days, 1 and 3 months after operation. Statistical significant difference (P ¼ 0.03) was found in the data of feeling of a foreign body 1 year after surgery: the symptom was mentioned in 6 (6.3%) patients in LW group and 17 (16.7%) patients in HW group. 2 years after surgery the same symptom was detected in 2 (2.1%) patients in LW group
1382
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384
Fig. 1. Study flow chart. A randomized trial of lightweight vs. heavyweight mesh in Lichtenstein primary inguinal hernia repair.
and 11 (10.8%) e in HW group e difference is statistical significant (P ¼ 0.02). 3 years after surgery the feeling of a foreign body was marked in 1 (1.05%) patient in LW group and 9 (9.4%) in HW group e difference is statistical significant (P ¼ 0.02) (Table 5). 5. Discussion A tension-free operation with mesh has become the standard technique for inguinal hernia surgery [1]. According to the scientific literature the frequency of hernia recurrence is considerably low after mesh repair [1,2,18,19]. Although chronic pain and feeling of a foreign body in inguinal area is the main problems of mesh repair surgery. These complications significantly effect on the quality of patients life [3e6,12,20]. Several investigators confirm that the main reasons of these complications are the reaction of organism on a foreign body (polypropylene). Thus, a lightweight mesh with a reduced weight of non-absorbable components has been developed to minimize foreign body reactions after surgery [7e10,21]. The purpose of our clinical study was to evaluate the outcomes of Lichtenstein hernioplasty by using light and heavy weight meshes and to compare them to the results of analogs researches. According to our research frequency of early postoperative complications (infection, hematoma, seroma) in both groups were the same. These results are in accordance to other investigations [13,22e24]. There was no detectable difference by of hernia recurrence between the two groups. Our results did not differ from results of other investigations [11,14,15,25,26]. Different kinds of metaanalysis found no statistical difference in overall hernia
recurrence between LW and HW mesh in inguinal hernia repair [13,23,24,27,28]. It's worth to mention the work of O'Dwyer et al. [29], where hernia recurrence was statistically significantly higher in LW group compared to HW group. The authors don't correlate the increase of frequency of recurrence of the type of mesh. According to their opinion the cause of this difference is technical errors of mesh fixation. We think particular attention have to paid to lightweight mesh fixation to avoid hernia recurrence in Lichtenstein hernioplasty. We completely agree the authors' opinion about three additional modification of LW mesh fixation to be considered during Lichtenstein hernioplasty [25,27,29]. Importance of lightweight mesh fixation for prevention of hernia recurrence is emphasized also in European Hernia Society guidelines update [30]. Chronic pain is one of the most serious long-term complications following groin hernia repair [1,3,5,6,20,30]. No statistical difference has been found between LW and HW groups by chronic pain 1, 2, and 3 years after surgery. Several scientific articles confirm our result [14,15,25,26]. Otherwise some scientific results show the chronic pain is significantly decreased in LW group [11e13,16,22e24,28,29]. According to the European Hernia Society guidelines on treatment of inguinal hernia in adult patients, the risk factors for chronic pain are preoperative pain, younger age and severe early postoperative pain [1]. We mentioned an interesting fact: acute severe pain was observed on 7th day after surgery in patients of both groups who 1, 2 or 3 years after hernioplasty had chronic pain. Based on our results the feeling of a foreign body in groin is similar in both groups after 1 and 3 month. Significant decrease of
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384 Table 1 Preoperative factors in two treatment groups. Characteristics
Sex Male Female Age (years) BMI, kg/m2 Site of hernia Right Left Comorbidities Cardiovascular Respiratory system Diabetes ASA risk group 1 2 3 Current smoker Occupation Light work Physical work
1383
Table 4 Pain and visual analogue scale (VAS) at follow-up.
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
P Value
90 6 54.7(14.3) 24.4(1.7)
92 10 51.3 (17.5) 24.6(1.8)
56 40
64 38
0.56
11 4 3
10 5 5
0.82 0.75 0.72
36 50 10 41
42 54 6 47
0.67 0.67 0.30 0.74
54 42
48 54
0.25
0.44 0.14 0.42
Characteristics
7 days Pain VAS 1 month Pain VAS 3 month Pain VAS 1 year Pain VAS 2 year Pain VAS 3 year Pain Vas
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102
P Value
13(13.5) 3.2 ± 2.3
17(16.7) 3 ± 1.7
0.56 0.84
12(12.5) 3.2 ± 1.8
15(14.7) 2.6 ± 1.3
0.68 0.37
10(10.4) 2.5 ± 1.4
12(11.8) 2.4 ± 1.3
0.82 0.82
6(6.3) 2.2 ± 1.2
9(8.8) 2.4 ± 1.4
0.60 0.70
3(3.1) 2.3 ± 1.5
6(5.9) 2.5 ± 1.1
0.50 0.85
2(2.1) 2 ± 1.4
5(4.9) 2.4 ± 1.1
0.45 0.71
VAS e Visual Analogue Scale. Data are expressed as absolute number of patients (%) or as mean and SD.
ASA e American Society of Anesthesiologists; BMI e Body mass index. Data are expressed as mean (SD) or absolute number of patients (%). Table 5 Identifying feeling of foreign body. Table 2 Intraoperative factors in two treatment groups. Characteristics
Type of hernia Indirect Direct Combined Anesthesia Local General Prophylactic antibiotic Operation time, min.
Characteristics
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
P Value
62(64.6) 30(31.3) 4(4.1)
71(69.6) 27(26.5) 4(3.9)
0.54 0.53 0.99
76 20 28 58.7(13.3)
78 24 26 61.2(9.9)
0.73 0.63 0.13
Data are expressed as mean (SD) or absolute number of patients (%).
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
Feeling of foreign body 7 days 33(34.4) 1 month 24(25) 3 month 19(19.8) 1 year 6(6.3) 2 year 2(2.1) 3 year 1(1.05)
30(29.4) 27(26.5) 23(22.5) 17(16.7) 11(10.8) 9(9.4)
P Value
0.54 0.87 0.73 0.03 0.02 0.02
Data are expressed as absolute number of patients (%).
body than that of the HW mesh. That can be considered as an advantage of LW mesh rather than HW mesh. Ethical approval
Table 3 Surgical outcomes in two treatment groups. Characteristics
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
Hospital stay (days) Sick leave (days) Primary complication Wound infection Hematoma Seroma Recurrence
1.4(0.8) 8.4(2.1) 8 3 1 4 1(1.04)
1.5(0.7) 8.8(1.8) 10 3 1 6 1(0.98)
P Value
None. Sources of funding
0.35 0.15 0.80 1.0 1.0 0.75 0.99
Data are expressed as mean (SD) or absolute number of patients (%).
the symptom has been found is in LW group 1, 2 or 3 years after surgery (P ¼ 0.03, P ¼ 0.02, P ¼ 0.02, respectively). Several investigations confirm our results underlining the prevalence of lightweight mesh concerning feeling of a foreign body [11,13,16,22e28], but work of Nikkolo et al. [15] shows no difference in this indicator between compared groups. In conclusion, based on our observational study comparison of LW and HW meshes usage in Lichtenstein hernioplasty in primary inguinal hernia, indicated no significant difference in terms of wound complications, hernia recurrence and chronic pain. The usage of the LW mesh was associated with less feeling of foreign
None. Author contribution Zaza Demetrashvili participated in the design and coordination of the study, collected the data, analysed the data, carried out the statistical analysis and wrote the manuscript. Kakhi Khutsishvili, Irakli Pipia, Giorgi Kenchadze and Eka Ekaladze developed the literature search, collected the data and assisted in writing up. All authors read and approved the final manuscript. Conflicts of interest The authors declare that they have no conflict of interests. Acknowledgments We are thankful to Dr George Kamkamidze for the help he provided during the writing of the article.
1384
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384
References [1] M.P. Simons, T. Aufenacker, M. Bay-Nielsen, J.L. Bouillot, G. Campanelli, J. Conze, et al., European hernia society guidelines on the treatment of inguinal hernia in adult patients, Hernia 13 (2009) 343e403. [2] EU Hernia Trialists Collaboration, Mesh compared with non-mesh methods of groin hernia repair: systematic review of randomized control trials, Br. J. Surg. 87 (2000) 854e859. [3] H. Kehlet, M. Bay-Nielsen, Danish Hernia Database Collaboration, Nationwide quality improvement of groin hernia repair from the Danish Hernia database of 87840 patients from 1998 to 2005, Hernia 12 (2008) 1e7. [4] S. Massaron, S. Bona, U. Fumagalli, P. Valente, R. Rosati, Long-term sequele after 1311 primary inguinal hernia repairs, Hernia 12 (2008) 57e63. [5] S. Alfieri, P.K. Amid, G. Campanelli, G. Izard, H. Kehlet, A.R. Wijsmuller, et al., International guidelines for prevention and management of post-operative chronic pain following inguinal hernia surgery, Hernia 15 (2011) 239e249. [6] H. Paajanen, T. Scheinin, J. Vironen, Commentary: nationwide analysis of complications related to inguinal hernia surgery in Finland: a 5 year register study of 55,000 operations, Am. J. Surg. 199 (2010) 746e751. [7] U. Klinge, B. Klosterhalfen, M. Muller, V. Schumpelick, Foreign body reaction to meshes used for the repair of abdominal wall hernias, Eur. J. Surg. 165 (1999) 665e673. [8] K. Junge, U. Klinge, R. Rosch, B. Klosterhalfen, V. Schumpelick, Functional and morphologic properties of modified mesh for inguinal hernia repair, World J. Surg. 26 (2002) 1472e1480. [9] U. Klinge, J.K. Park, B. Klosterhalfen, The ideal mesh? Pathobiology 80 (2013) 169e175. [10] W.S. Cobb, K.W. Kercher, B.T. Heniford, The argument for lightweight polypropylene mesh in hernia repair, Surg. Innov. 12 (2005) 63e69. [11] S. Bringman, S. Wollert, J. Osterberg, S. Smedberg, H. Granuland, T.J. Heikkinen, Three-year results of a randomized clinical trial of lightweight or standard polypropylene mesh in Lichtenstein repair of primary inguinal hernia, Br. J. Surg. 93 (2006) 1056e1059. [12] S. Nienhuijs, E. Staal, L. Strobbe, C. Rosman, H. Groenewoud, R. Bleichrodt, Chronic pain after mesh repair of inguinal hernia: a systematic review, Am. J. Surg. 194 (2007) 394e400. [13] J. Li, Z. Ji, T. Cheng, Lightweight versus heavyweight in inguinal hernia repair: a meta-analysis, Hernia 16 (2012) 529e539. [14] H. Paajanen, A Single-surgeon randomized trial comparing three composite meshes on chronic pain after Lichtenstein hernia repair in local anesthesia, Hernia 11 (2007) 335e339. [15] C. Nikkolo, M. Murruste, T. Vaasna, H. Seepter, T. Tikk, U. Lepner, Three-year results of randomized clinical trial comparing lightweight mesh with heavyweight mesh for inguinal hernioplasty, Hernia 16 (2012) 555e559. [16] D. Weyhe, O. Belyaev, C. Muller, K. Meurer, K.H. Bauer, G. Papapostolou, W. Uhl, Improving outcomes in hernia repair by the use light meshes e a
[17] [18]
[19]
[20] [21]
[22]
[23]
[24]
[25]
[26]
[27]
[28]
[29]
[30]
comparison of different implant constructions based on critical appraisal of the literature, World J. Surg. 31 (2007) 234e244. I.L. Lichtenstein, A.G. Schulman, P.K. Amid, M.M. Montllor, The tension-free hernioplasty, Am. J. Surg. 157 (1989) 188e193. N.W. Scott, K. McCormack, P. Graham, P.M. Go, S.J. Ross, A.M. Grant, Open mesh versus non-mesh for repair of femoral and inguinal hernia, Cochrane Database Syst. Rev. 4 (2002) CD002197. R.N. van Veen, A.R. Wijsmuller, W.W. Wrijland, W.C. Hop, J.F. Lange, J. Jeekel, Long-term follow-up of randomized clinical trial of non-mesh versus mesh repair of primary inguinal hernia, Br. J. Surg. 94 (2007) 506e510. S. Bringman, J. Conze, D. Cuccurullo, J. Deprest, K. Junge, B. Klosterhalfen, et al., Hernia repair: the search for ideal meshes, Hernia 14 (2010) 81e87. S.B. Orenstein, E.R. Saberski, D.L. Kreutzer, Y.W. Novitsky, Comparative analysis of histopathologic effects of synthetic meshes based on material, weight and pore size in mice, J. Surg. Res. 176 (2012) 423e429. S. Post, B. Weiss, M. Willer, T. Neufang, D. Lorenz, Randomized clinical trial of lightweight composite mesh for Lichtenstein inguinal hernia repair, Br. J. Surg. 91 (2004) 44e48. C. Zhong, B. Wu, Z. Yang, X. Deng, J. Kang, B. Guo, Y. Fan, A meta-analysis comparing lightweight meshes with heavyweight meshes in Lichtenstein inguinal hernia repair, Surg. Innov. 20 (2013) 24e31. M.M. Uzzaman, K. Ratnasingham, N. Ashraf, Meta-analysis of randomized controlled trials comparing lightweight and heavyweight mesh of Lichtenstein inguinal hernia repair, Hernia 16 (2012) 505e518. K. Bury, M. Smietanski, Polish Hernia Study Group, Five-year results of randomized clinical trial comparing a polypropylene mesh with a poliglecaprone and polypropylene composite mesh for inguinal hernioplasty, Hernia 16 (2012) 549e553. A. Yazdankhah Kenary, S.N. Afshin, H. Ahmad Amoli, A. Yagoobi Notash, A. Barjian, A. Yagoobi Notash Jr., et al., Randomized control trial comparing lightweight mesh with heavyweight mesh for primary inguinal repair, Hernia 17 (2013) 471e477. M. Smietanski, I.A. Smietanska, A. Modrzejewski, M.P. Simons, T.J. Aufenacker, Systematic review and meta-analysis of heavy and lightweight polypropylene mesh in Lichtenstein inguinal hernioplasty, Hernia 16 (2012) 519e528. M.S. Sajid, C. Leaver, M.K. Baig, P. Sains, Systematic review and meta-analysis of the use of lightweight versus heavyweight mesh in open inguinal hernia repair, Br. J. Surg. 99 (2012) 29e37. P.J. O'Dwyer, A.N. Kingsnorth, R.G. Molloy, P.K. Small, B. Lammers, G. Horeyseck, Randomized clinical trial assessing impact of lightweight or heavyweight mesh on chronic pain after inguinal hernia repair, Br. J. Surg. 92 (2005) 166e170. M. Miserez, E. Peeters, T. Aufenacker, J.L. Bouillot, G. Campanelli, J. Conze, et al., Update with level 1 studies of the European Hernia society guidelines on the treatment of inguinal hernia in adult patients, Hernia 18 (2014) 151e163.
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Original research
Standard polypropylene mesh vs lightweight mesh for Lichtenstein repair of primary inguinal hernia: A randomized controlled trial Zaza Demetrashvili a, b, *, Kakhi Khutsishvili b, Irakli Pipia b, Giorgi Kenchadze b, Eka Ekaladze c a b c
Department of Surgery of Tbilisi State Medical University, 33, Vazha-Pshavela ave., 0177 Tbilisi, Georgia Department of General Surgery of Kipshidze Central University Hospital, 29, Vazha-Pshavela ave., 0160 Tbilisi, Georgia Department of Biochemistry of Tbilisi State Medical University, 33, Vazha-Pshavela ave., 0177 Tbilisi, Georgia
h i g h l i g h t s During Lichtenstein with polypropylene mesh, the worst characteristics can be chronic pain. In order to prevent such kind of difficulties, the usage of lightweight mesh is recommended. The usage of the LW mesh was associated with less feeling of foreign body than that of the HW mesh. Thepoint listed above can be considered as an advantage of LW mesh rather than HW mesh.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 4 August 2014 Received in revised form 13 October 2014 Accepted 25 October 2014 Available online 28 October 2014
Purpose: The aim of the present clinical study was to compare early and late outcomes after inguinal hernia repair with the heavyweight mesh (HW) and lightweight mesh (LW) during a 3 year follow-up period. Methods: 226 patients were randomized into LW and HW mesh groups, both of which underwent unilateral primary inguinal hernia repair via the Lichtenstein technique. Wound complications (infection, hematoma, seroma), hernia recurrence, pain and feeling of foreign body in inguinal area were determined in patients. Pain was measured by visual analogue scale. Results: No statistical difference has been found between LW and HW groups by wound complication (P ¼ 0.80). One case of hernia recurrence has been mentioned in both groups one year after hernioplasty. But there was no detectable difference between the two groups. No significant difference has been found between LW and HW groups by frequency of chronic pain 7 days, 1 and 3 months, 1, 2, and 3 years after surgery. As for the feeling of foreign body in groin it is similar in both groups after 1 and 3 months. Level of feeling of foreign body was significantly lower in LW group 1, 2, and 3 years after surgery, than in HW group (P ¼ 0.03, P ¼ 0.02, P ¼ 0.02, respectively). Conclusion: Our research shows no significant difference in wound complications, hernia recurrence and chronic pain after Lichtenstein hernioplasty, by using of LW and HW meshes. The usage of the LW mesh was associated with less feeling of foreign body than that of the HW mesh, what can be considered as prevalence of LW mesh hernioplasty. © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
Keywords: Lightweight mesh Heavyweight mesh Lichtenstein Inguinal hernia
1. Introduction Inguinal hernia repair is one of the most frequently performed operations in general surgery. Tension-free mesh repair currently is the gold standard in inguinal hernia surgery. Currently the
* Corresponding author. Department of Surgery of Tbilisi State Medical University, 33, Vazha-Pshavela ave., 0177 Tbilisi, Georgia. E-mail addresses: [email protected] (Z. Demetrashvili), kkhutsishvili1972@ yahoo.com (K. Khutsishvili), [email protected] (I. Pipia), [email protected] (G. Kenchadze), [email protected] (E. Ekaladze). http://dx.doi.org/10.1016/j.ijsu.2014.10.025 1743-9191/© 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
Lichtenstein method is one of the most popular techniques [1]. Usage of prosthetic materials decreased the frequency of hernia recurrence, although the chronic pain and feeling of a foreign body in inguinal area after surgery is still considerable problem e it worsens the level of patients' quality of life [2e4]. The incidence of chronic pain after inguinal hernioplasty varies from 9 to 52% and the feeling of a foreign body occurs in around 40% of patients [3,5,6]. The pain may be caused by damage to the inguinal nerves, but these complications may be due to the foreign body reaction against the mesh which results in an inflammatory response and scar tissue formation [5,7]. The reaction on foreign
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384
body is depend on the type and volume, as well as the size of pores and web-structure of synthetic prosthesis. Taking into consideration this fact, nowadays partially absorbable lightweight meshes (LW) are being used instead of heavyweight polypropylene meshes (HW). Low mass, decreased content of foreign body and large pores are characteristic for LW [8e10]. According to the current researches usage of LW meshes for inguinal hernioplasty decreases the frequency of chronic pain [11e13], at the same time several articles don't confirm the fact [14,15]. It's worth mentioning, that the risk of hernia recurrence might be increased in case of using LW meshes [16]. The aim of the present clinical study was to compare early and late outcomes after inguinal hernia repair via the Lichtenstein technique with the heavyweight mesh (HW) and lightweight mesh (LW) during a 3 year follow-up period. 2. Methods From January 2008 to April 2011 patients over 18 years of age who underwent elective surgery for unilateral primary inguinal hernia via the Lichtenstein technique were enrolled in the study. The patients were operated at the General Surgery Department of Kiphshidze Central University Hospital. The inclusion criteria were a unilateral primary inguinal hernia requiring operative treatment and patient's approval to participate in the study. The exclusion criteria were bilateral hernia, irreducible hernia, recurrent hernia, strangulated hernia, a patient's preference for either mesh type, or a patient's refusal to participate in the study. The basic principle for this study was one unit, one surgeon trained in the standard Lichtenstein technique and the use of LW and HW meshes. The patients were assigned to one of the two groups: the LW group or the HW group. The randomization (by simple random sampling) of patients to each of the two groups described above was done before the surgical intervention. The assignment of patients to the specific groups was performed by the clinical manager not involved in the surgical procedures. The study participants were blinded regarding the type of the mesh used in the surgical intervention. The Lichtenstein hernioplasty was performed according to the original description of the technique [17]. The nerves in inguinal canal were identified and preserved when possible. In the HW group, a monofilament polypropylene mesh with a weight of 82 g/m2 and pore size 0.8 mm (Prolene, Ethicon, Somerville, New Jersey) was used. The LW mesh in this study was Ultrapro (Ultrapro, Ethicon, Somerville, New Jersey), a large pore composite mesh (polypropylene and poliglecaprone, Monocril) (weight ¼ 28 g/m2, pore size 3 mm). In both groups, 8 12 cm mesh was applied. Polypropylene 2/0 monofilament suture material was used for mesh implantation. Several preoperative factors were studied, which included sex, age, body mass index, occupation, tobacco use, risk groups by American Society of Anesthesiologists (ASA) and comorbidities, and site of hernia. Patients with ASA groups 4 and 5 were excluded from the study. Among the intraoperative factors, the following were evaluated: type of hernia, anesthesia method (local, general), and duration of the operation. Prophylactic antibiotics were not used in all patients. We were using it only in patients with concurrent disorders. In these instances, 1.5 g cefuroxime was used intravenously 30 min before the operation. Among the postoperative data, the following were studied: postoperative days at the ward (hospital stay), sick-leave days, and complications. The latter were divided into two groups: early and late complications. The early complications included wound infection, hematoma, and seroma. The late complications included chronic pain in the inguinal region, the feeling of a foreign body and
1381
hernia recurrence. Pain scores were measured on a Visual Analogue Scale (VAS), ranging from 0 (no pain) to 10 (worst imaginable pain). After discharge from the hospital, all patients were examined after 1 week, 15 days, and 1 month at the outpatient department by the same surgeon who performed the operation. Also, these patients were examined 3 month, 1, 2, and 3 years after the operation date. The examinations were performed by surgeons who had not been participating previously in this study. They were paying attention to the pain in the inguinal region, to the feeling of a foreign body and the presence of hernia recurrence. The pain questionnaire included questions regarding pain at rest, on coughing, while climbing steps and during physical activity. 3. Statistical methods Descriptive statistics methods were used to characterize each variable. Comparison of continuous variables was performed by independent samples t-test or the ManneWhitney U test according to the normality of the variables. Categorical variables were evaluated by two-tailed Chi-square test or Fisher's exact test where appropriate. The threshold for statistical significance was set to P < 0.05. Statistical tests were performed by SPSS 16.00 (SPSS Inc., Chicago, IL). 4. Results From January 2008 to April 2011, 328 patients underwent inguinal hernia repair via Lichtenstein technique. Among these patients, 226 were randomized in two groups equally (113 patients in each group). All of these patients underwent the allocated operations. Information about 28 patients was lost during the time observation: among them e 19 patients were not coming for examination, 7 patients were died during observation period (the causes of death were all non-hernia surgery related), in 2 patients developed recurrence of hernia. Subsequently 102 patients from HW group and 96 e from LW group were consecutively examined during 3 years after surgical operation. The data of this investigation is analyzed on this article (Fig. 1). Both groups were similar by preoperative (sex, age, body mass index, tobacco use, American Society of Anesthesiologists risk groups, comorbidities, site of hernia, and occupation) and intraoperative (type of hernia, anesthesia, prophylactic antibiotics, and operation time) factors. No statistically significant differences were found between the groups by these factors (Table 1, Table 2). Regarding the postoperative data, no statistical difference has been found (P ¼ 0.35) between groups by postoperative time spent at the ward (hospital stay), and by sick-leave days (P ¼ 0.15). In the LW group, 8 early complications (wound infection, hematoma, seroma) were observed (8.3%), in the HW group e 10 early complications (9.8%). The difference did not statistical significant (P ¼ 0.80). One case of hernia recurrence was marked in each group after 1 year of surgery. But there was no detectable difference between the two groups (Table 3). As for frequency of inguinal pain the difference was not statistically significant between LW and HW groups 7 days, 1 and 3 month and 1, 2 and 3 years after surgery. There was no detectable difference between the two groups according to average VAS scores too (Table 4). The difference was not statistically detectable between LW and HW groups concerning the feeling of a foreign body 7 days, 1 and 3 months after operation. Statistical significant difference (P ¼ 0.03) was found in the data of feeling of a foreign body 1 year after surgery: the symptom was mentioned in 6 (6.3%) patients in LW group and 17 (16.7%) patients in HW group. 2 years after surgery the same symptom was detected in 2 (2.1%) patients in LW group
1382
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384
Fig. 1. Study flow chart. A randomized trial of lightweight vs. heavyweight mesh in Lichtenstein primary inguinal hernia repair.
and 11 (10.8%) e in HW group e difference is statistical significant (P ¼ 0.02). 3 years after surgery the feeling of a foreign body was marked in 1 (1.05%) patient in LW group and 9 (9.4%) in HW group e difference is statistical significant (P ¼ 0.02) (Table 5). 5. Discussion A tension-free operation with mesh has become the standard technique for inguinal hernia surgery [1]. According to the scientific literature the frequency of hernia recurrence is considerably low after mesh repair [1,2,18,19]. Although chronic pain and feeling of a foreign body in inguinal area is the main problems of mesh repair surgery. These complications significantly effect on the quality of patients life [3e6,12,20]. Several investigators confirm that the main reasons of these complications are the reaction of organism on a foreign body (polypropylene). Thus, a lightweight mesh with a reduced weight of non-absorbable components has been developed to minimize foreign body reactions after surgery [7e10,21]. The purpose of our clinical study was to evaluate the outcomes of Lichtenstein hernioplasty by using light and heavy weight meshes and to compare them to the results of analogs researches. According to our research frequency of early postoperative complications (infection, hematoma, seroma) in both groups were the same. These results are in accordance to other investigations [13,22e24]. There was no detectable difference by of hernia recurrence between the two groups. Our results did not differ from results of other investigations [11,14,15,25,26]. Different kinds of metaanalysis found no statistical difference in overall hernia
recurrence between LW and HW mesh in inguinal hernia repair [13,23,24,27,28]. It's worth to mention the work of O'Dwyer et al. [29], where hernia recurrence was statistically significantly higher in LW group compared to HW group. The authors don't correlate the increase of frequency of recurrence of the type of mesh. According to their opinion the cause of this difference is technical errors of mesh fixation. We think particular attention have to paid to lightweight mesh fixation to avoid hernia recurrence in Lichtenstein hernioplasty. We completely agree the authors' opinion about three additional modification of LW mesh fixation to be considered during Lichtenstein hernioplasty [25,27,29]. Importance of lightweight mesh fixation for prevention of hernia recurrence is emphasized also in European Hernia Society guidelines update [30]. Chronic pain is one of the most serious long-term complications following groin hernia repair [1,3,5,6,20,30]. No statistical difference has been found between LW and HW groups by chronic pain 1, 2, and 3 years after surgery. Several scientific articles confirm our result [14,15,25,26]. Otherwise some scientific results show the chronic pain is significantly decreased in LW group [11e13,16,22e24,28,29]. According to the European Hernia Society guidelines on treatment of inguinal hernia in adult patients, the risk factors for chronic pain are preoperative pain, younger age and severe early postoperative pain [1]. We mentioned an interesting fact: acute severe pain was observed on 7th day after surgery in patients of both groups who 1, 2 or 3 years after hernioplasty had chronic pain. Based on our results the feeling of a foreign body in groin is similar in both groups after 1 and 3 month. Significant decrease of
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384 Table 1 Preoperative factors in two treatment groups. Characteristics
Sex Male Female Age (years) BMI, kg/m2 Site of hernia Right Left Comorbidities Cardiovascular Respiratory system Diabetes ASA risk group 1 2 3 Current smoker Occupation Light work Physical work
1383
Table 4 Pain and visual analogue scale (VAS) at follow-up.
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
P Value
90 6 54.7(14.3) 24.4(1.7)
92 10 51.3 (17.5) 24.6(1.8)
56 40
64 38
0.56
11 4 3
10 5 5
0.82 0.75 0.72
36 50 10 41
42 54 6 47
0.67 0.67 0.30 0.74
54 42
48 54
0.25
0.44 0.14 0.42
Characteristics
7 days Pain VAS 1 month Pain VAS 3 month Pain VAS 1 year Pain VAS 2 year Pain VAS 3 year Pain Vas
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102
P Value
13(13.5) 3.2 ± 2.3
17(16.7) 3 ± 1.7
0.56 0.84
12(12.5) 3.2 ± 1.8
15(14.7) 2.6 ± 1.3
0.68 0.37
10(10.4) 2.5 ± 1.4
12(11.8) 2.4 ± 1.3
0.82 0.82
6(6.3) 2.2 ± 1.2
9(8.8) 2.4 ± 1.4
0.60 0.70
3(3.1) 2.3 ± 1.5
6(5.9) 2.5 ± 1.1
0.50 0.85
2(2.1) 2 ± 1.4
5(4.9) 2.4 ± 1.1
0.45 0.71
VAS e Visual Analogue Scale. Data are expressed as absolute number of patients (%) or as mean and SD.
ASA e American Society of Anesthesiologists; BMI e Body mass index. Data are expressed as mean (SD) or absolute number of patients (%). Table 5 Identifying feeling of foreign body. Table 2 Intraoperative factors in two treatment groups. Characteristics
Type of hernia Indirect Direct Combined Anesthesia Local General Prophylactic antibiotic Operation time, min.
Characteristics
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
P Value
62(64.6) 30(31.3) 4(4.1)
71(69.6) 27(26.5) 4(3.9)
0.54 0.53 0.99
76 20 28 58.7(13.3)
78 24 26 61.2(9.9)
0.73 0.63 0.13
Data are expressed as mean (SD) or absolute number of patients (%).
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
Feeling of foreign body 7 days 33(34.4) 1 month 24(25) 3 month 19(19.8) 1 year 6(6.3) 2 year 2(2.1) 3 year 1(1.05)
30(29.4) 27(26.5) 23(22.5) 17(16.7) 11(10.8) 9(9.4)
P Value
0.54 0.87 0.73 0.03 0.02 0.02
Data are expressed as absolute number of patients (%).
body than that of the HW mesh. That can be considered as an advantage of LW mesh rather than HW mesh. Ethical approval
Table 3 Surgical outcomes in two treatment groups. Characteristics
Lightweight mesh
Heavyweight mesh
(n ¼ 96)
(n ¼ 102)
Hospital stay (days) Sick leave (days) Primary complication Wound infection Hematoma Seroma Recurrence
1.4(0.8) 8.4(2.1) 8 3 1 4 1(1.04)
1.5(0.7) 8.8(1.8) 10 3 1 6 1(0.98)
P Value
None. Sources of funding
0.35 0.15 0.80 1.0 1.0 0.75 0.99
Data are expressed as mean (SD) or absolute number of patients (%).
the symptom has been found is in LW group 1, 2 or 3 years after surgery (P ¼ 0.03, P ¼ 0.02, P ¼ 0.02, respectively). Several investigations confirm our results underlining the prevalence of lightweight mesh concerning feeling of a foreign body [11,13,16,22e28], but work of Nikkolo et al. [15] shows no difference in this indicator between compared groups. In conclusion, based on our observational study comparison of LW and HW meshes usage in Lichtenstein hernioplasty in primary inguinal hernia, indicated no significant difference in terms of wound complications, hernia recurrence and chronic pain. The usage of the LW mesh was associated with less feeling of foreign
None. Author contribution Zaza Demetrashvili participated in the design and coordination of the study, collected the data, analysed the data, carried out the statistical analysis and wrote the manuscript. Kakhi Khutsishvili, Irakli Pipia, Giorgi Kenchadze and Eka Ekaladze developed the literature search, collected the data and assisted in writing up. All authors read and approved the final manuscript. Conflicts of interest The authors declare that they have no conflict of interests. Acknowledgments We are thankful to Dr George Kamkamidze for the help he provided during the writing of the article.
1384
Z. Demetrashvili et al. / International Journal of Surgery 12 (2014) 1380e1384
References [1] M.P. Simons, T. Aufenacker, M. Bay-Nielsen, J.L. Bouillot, G. Campanelli, J. Conze, et al., European hernia society guidelines on the treatment of inguinal hernia in adult patients, Hernia 13 (2009) 343e403. [2] EU Hernia Trialists Collaboration, Mesh compared with non-mesh methods of groin hernia repair: systematic review of randomized control trials, Br. J. Surg. 87 (2000) 854e859. [3] H. Kehlet, M. Bay-Nielsen, Danish Hernia Database Collaboration, Nationwide quality improvement of groin hernia repair from the Danish Hernia database of 87840 patients from 1998 to 2005, Hernia 12 (2008) 1e7. [4] S. Massaron, S. Bona, U. Fumagalli, P. Valente, R. Rosati, Long-term sequele after 1311 primary inguinal hernia repairs, Hernia 12 (2008) 57e63. [5] S. Alfieri, P.K. Amid, G. Campanelli, G. Izard, H. Kehlet, A.R. Wijsmuller, et al., International guidelines for prevention and management of post-operative chronic pain following inguinal hernia surgery, Hernia 15 (2011) 239e249. [6] H. Paajanen, T. Scheinin, J. Vironen, Commentary: nationwide analysis of complications related to inguinal hernia surgery in Finland: a 5 year register study of 55,000 operations, Am. J. Surg. 199 (2010) 746e751. [7] U. Klinge, B. Klosterhalfen, M. Muller, V. Schumpelick, Foreign body reaction to meshes used for the repair of abdominal wall hernias, Eur. J. Surg. 165 (1999) 665e673. [8] K. Junge, U. Klinge, R. Rosch, B. Klosterhalfen, V. Schumpelick, Functional and morphologic properties of modified mesh for inguinal hernia repair, World J. Surg. 26 (2002) 1472e1480. [9] U. Klinge, J.K. Park, B. Klosterhalfen, The ideal mesh? Pathobiology 80 (2013) 169e175. [10] W.S. Cobb, K.W. Kercher, B.T. Heniford, The argument for lightweight polypropylene mesh in hernia repair, Surg. Innov. 12 (2005) 63e69. [11] S. Bringman, S. Wollert, J. Osterberg, S. Smedberg, H. Granuland, T.J. Heikkinen, Three-year results of a randomized clinical trial of lightweight or standard polypropylene mesh in Lichtenstein repair of primary inguinal hernia, Br. J. Surg. 93 (2006) 1056e1059. [12] S. Nienhuijs, E. Staal, L. Strobbe, C. Rosman, H. Groenewoud, R. Bleichrodt, Chronic pain after mesh repair of inguinal hernia: a systematic review, Am. J. Surg. 194 (2007) 394e400. [13] J. Li, Z. Ji, T. Cheng, Lightweight versus heavyweight in inguinal hernia repair: a meta-analysis, Hernia 16 (2012) 529e539. [14] H. Paajanen, A Single-surgeon randomized trial comparing three composite meshes on chronic pain after Lichtenstein hernia repair in local anesthesia, Hernia 11 (2007) 335e339. [15] C. Nikkolo, M. Murruste, T. Vaasna, H. Seepter, T. Tikk, U. Lepner, Three-year results of randomized clinical trial comparing lightweight mesh with heavyweight mesh for inguinal hernioplasty, Hernia 16 (2012) 555e559. [16] D. Weyhe, O. Belyaev, C. Muller, K. Meurer, K.H. Bauer, G. Papapostolou, W. Uhl, Improving outcomes in hernia repair by the use light meshes e a
[17] [18]
[19]
[20] [21]
[22]
[23]
[24]
[25]
[26]
[27]
[28]
[29]
[30]
comparison of different implant constructions based on critical appraisal of the literature, World J. Surg. 31 (2007) 234e244. I.L. Lichtenstein, A.G. Schulman, P.K. Amid, M.M. Montllor, The tension-free hernioplasty, Am. J. Surg. 157 (1989) 188e193. N.W. Scott, K. McCormack, P. Graham, P.M. Go, S.J. Ross, A.M. Grant, Open mesh versus non-mesh for repair of femoral and inguinal hernia, Cochrane Database Syst. Rev. 4 (2002) CD002197. R.N. van Veen, A.R. Wijsmuller, W.W. Wrijland, W.C. Hop, J.F. Lange, J. Jeekel, Long-term follow-up of randomized clinical trial of non-mesh versus mesh repair of primary inguinal hernia, Br. J. Surg. 94 (2007) 506e510. S. Bringman, J. Conze, D. Cuccurullo, J. Deprest, K. Junge, B. Klosterhalfen, et al., Hernia repair: the search for ideal meshes, Hernia 14 (2010) 81e87. S.B. Orenstein, E.R. Saberski, D.L. Kreutzer, Y.W. Novitsky, Comparative analysis of histopathologic effects of synthetic meshes based on material, weight and pore size in mice, J. Surg. Res. 176 (2012) 423e429. S. Post, B. Weiss, M. Willer, T. Neufang, D. Lorenz, Randomized clinical trial of lightweight composite mesh for Lichtenstein inguinal hernia repair, Br. J. Surg. 91 (2004) 44e48. C. Zhong, B. Wu, Z. Yang, X. Deng, J. Kang, B. Guo, Y. Fan, A meta-analysis comparing lightweight meshes with heavyweight meshes in Lichtenstein inguinal hernia repair, Surg. Innov. 20 (2013) 24e31. M.M. Uzzaman, K. Ratnasingham, N. Ashraf, Meta-analysis of randomized controlled trials comparing lightweight and heavyweight mesh of Lichtenstein inguinal hernia repair, Hernia 16 (2012) 505e518. K. Bury, M. Smietanski, Polish Hernia Study Group, Five-year results of randomized clinical trial comparing a polypropylene mesh with a poliglecaprone and polypropylene composite mesh for inguinal hernioplasty, Hernia 16 (2012) 549e553. A. Yazdankhah Kenary, S.N. Afshin, H. Ahmad Amoli, A. Yagoobi Notash, A. Barjian, A. Yagoobi Notash Jr., et al., Randomized control trial comparing lightweight mesh with heavyweight mesh for primary inguinal repair, Hernia 17 (2013) 471e477. M. Smietanski, I.A. Smietanska, A. Modrzejewski, M.P. Simons, T.J. Aufenacker, Systematic review and meta-analysis of heavy and lightweight polypropylene mesh in Lichtenstein inguinal hernioplasty, Hernia 16 (2012) 519e528. M.S. Sajid, C. Leaver, M.K. Baig, P. Sains, Systematic review and meta-analysis of the use of lightweight versus heavyweight mesh in open inguinal hernia repair, Br. J. Surg. 99 (2012) 29e37. P.J. O'Dwyer, A.N. Kingsnorth, R.G. Molloy, P.K. Small, B. Lammers, G. Horeyseck, Randomized clinical trial assessing impact of lightweight or heavyweight mesh on chronic pain after inguinal hernia repair, Br. J. Surg. 92 (2005) 166e170. M. Miserez, E. Peeters, T. Aufenacker, J.L. Bouillot, G. Campanelli, J. Conze, et al., Update with level 1 studies of the European Hernia society guidelines on the treatment of inguinal hernia in adult patients, Hernia 18 (2014) 151e163.
