|Year : 2012 | Volume
| Issue : 2 | Page : 64-69
Composite polypropylene mesh versus lightweight polypropylene mesh: The TAPP repair for laparoscopic inguinal hernia repair
Adil Bangash1, Nadim Khan2, Muzaffaruddin Sadiq2
1 Peshawar Institue of Medical Science, Peshawar, Pakistan
2 Lady Reading Hospital, Peshawar, Pakistan
|Date of Web Publication||1-Oct-2012|
Peshawar Institute of Medical Sciences, Peshawar
Source of Support: None, Conflict of Interest: None
Aims and Objectives: To determine the frequency of complications and pain scores post-operatively following TAPP (Transabdominal Pre-peritoneal)repair for inguinal hernia, comparing lightweight polypropylene versus the composite polypropylene mesh. Materials and Methods: This study was conducted at Lady Reading Hospital, Peshawar, from December 1, 2007, to November 30, 2011. Group A included all those patients with inguinal hernia that were operated using the TAPP method and extraperitoneal placement of the lightweight polypropylene mesh, whereas group B comprised of those patients that were placed a composite polypropylene mesh (VYPRO II R ). A pro forma was prepared to record all the relevant data such as the NYHUS classification of the type of hernia, the post-operative pain scale score, and the complications that included seroma formation, testicular pain and atrophy, preoperative injuries, surgical emphysema, adhesion obstruction, mesh infection, wound infection, and perioperative mortality. The planned sequence of follow-up after discharge of the patient was at 1 week, 1month, 3 months, 6 months, and one year. Data were analyzed using SPSS R for Windows version 13.0. Results: A total of 192 patients were operated, equally divided between both groups. The VYPRO II R group had a higher number of direct hernias and the operative time was also much less but this was not statistically significant (P=0.91). The mean hospital stay was slightly higher in the polypropylene group but that was also not significant (P=0.89). The frequency of seroma formation was higher in the polypropylene group (6.25%) and majority of these patients from both groups had larger scrotal hernias (P=0.34). The most significant finding in this study was the frequency of chronic pain with a visual analogue score of >3(1-10) after the six-month period was significantly higher in the polypropylene group (P=0.02). The recurrence rate was comparable in both groups with 3 patients in group B(P=0.62). Conclusions: No difference in the frequency of recurrence was observed over a one-year follow-up period but significant pain scores were observed in the polypropylene group. Studies with longer follow-up to rule the rate of recurrence in composite meshes will determine its benefit over the lightweight polypropylene meshes.
Keywords: Composite mesh, inguinal hernia, lightweight mesh, polypropylene, TAPP repair
|How to cite this article:|
Bangash A, Khan N, Sadiq M. Composite polypropylene mesh versus lightweight polypropylene mesh: The TAPP repair for laparoscopic inguinal hernia repair. J Sci Soc 2012;39:64-9
|How to cite this URL:|
Bangash A, Khan N, Sadiq M. Composite polypropylene mesh versus lightweight polypropylene mesh: The TAPP repair for laparoscopic inguinal hernia repair. J Sci Soc [serial online] 2012 [cited 2017 Mar 26];39:64-9. Available from: http://www.jscisociety.com/text.asp?2012/39/2/64/101843
| Introduction|| |
Approximately 75% of all abdominal wall hernias are seen in the groin.  Inguinal hernia is much more common in men than women. Although femoral and umbilical hernias are more common in female population, indirect inguinal hernia is still the most common type of hernia in women. Age is a factor for incidence and type of inguinal hernia; incidence increases by age.  Indirect hernia is more common in young and direct hernia in the elderly.
The introduction of meshes for the management of hernias beyond doubt paved the way to near zero recurrence following adequate repair, ,,, leaving the traditional suture repairs of historical importance. Such was the case in inguinal hernia but dramatically the advent of minimal invasive surgery saw a dramatic shift from the traditional inguinal approach to the laparoscopic variants. Both resulting in the preperitoneal placement of a mesh, the TEP (totally extraperitoneal) procedure dominates the laparoscopic arena by meta-analytic comparisons to date, showing it to be superior. ,, Even so due to steep learning curves of the laparoscopic procedures, some surgeons are still inclined to continue the inguinal approach in a fair share of their patients. A review published in 2007 reported that laparoscopic hernia repair is accounted for the minority of hernia repairs performed in the United States and some European countries, and this approach would likely remain a less common operation than open mesh repair.  NICE, in 2004, stated that only 4.1% of the all inguinal hernias were repaired by laparoscopic technique in the United Kingdom. ,
Usher first introduced polypropylene prosthetics for inguinal hernia in the late 1950s;  however, the wide acceptance of them took place in 1980s following Lichtenstein's report of very successful results. A hernia mesh has certain features like material, strength, elasticity, density, and pore size. Standard polypropylene mesh is the most frequently used one. It is cheap, available in most institutions, nonabsorbable, and strong enough to avoid hernia recurrence.  Nevertheless, some actual problems with mesh use like foreign body sensation and chronic postoperative pain have created a conflict about standard polypropylene mesh. Polyester mesh might be an alternative, but it could not gain popularity. Polyester meshes can degrade by time especially in infected area.
Newer lighter meshes have been produced to overcome these problems.  Nevertheless, all lightweight meshes are more expensive than standard polypropylene mesh. Pure polypropylene lightweight mesh is the most economic option. There are also coated polypropylene meshes in the market. The purpose of the coating is to attenuate the host response to the prosthetic, yet still provide adequate strength for repair.  Fish oil, beta glucan, and titanium have been used for coating. 
When meshes are categorized by density, a mesh with density >100 g/m 2 is accepted as heavy, whereas a 35-50 g/m 2 density is classified as lightweight.  Several recent controlled clinical studies have suggested that lightweight meshes may improve patient comfort. , Some objective findings in favor of lightweight meshes have also been obtained from laboratory experiments; however some others reported that a lower weight mesh does not correlate with a decreased biological response. 
Partially absorbable meshes have two components. Polypropylene nonabsorbable part does not lose its strength at all. The other half is absorbed within 12 weeks.  Eventually less foreign material is left in situ, while the remaining mesh can still provide a sufficient mechanical barrier against recurrence. ,
The focus in this study was to observe the rate of recurrence and frequency of complications following the use of the lightweight polypropylene mesh versus the composite polypropylene mesh (VYPRO R ).
| Materials and Methods|| |
This study was conducted at Lady Reading Hospital, Peshawar, from the 1 st of December 2007, till 30 th November 2011. The methods of the study, current practice, and cost incurred to the hospital and patient were documented and provided to the ethical committee of the Lady Reading Hospital, Peshawar. After obtaining their approval (RXQ-12-491), the sample size required was calculated from a similar study conducted by Chowbey et al.  The recurrence rate documented in the composite mesh group that was higher than the conventional heavy weight polypropylene mesh was 1.3%.
Using the sample size calculator of the Curative Research Systems R for a confidence level of 95% and a confidence interval limit of 10% the calculated sample size for each group was to be 96 patients in each group. Due to lack of a sample frame the adequate numbers of patients were alternately allocated into two groups during the entire study. Group A included all those patients with inguinal hernia that were operated using the TAPP method and extraperitoneal placement of the lightweight polypropylene mesh; whereas the second group comprised of those patients that were placed a composite polypropylene mesh (VYPRO II R ).
Patients of all ages were included in the study; even those patients that had recurrent hernia by the groin approach were included, as were those who had bilateral hernias. Those recurrent by a previous posterior approach, lack of fitness for general anesthesia and >ASAII were excluded from the study. Those patients that were lost during the follow-up and previous abdominal surgery were also excluded and allocation of further patients to respective group was done.
All patients were admitted through the outpatient department and following admission a formal consent explaining the inclusion of the patient in the trial was given by the attending surgeon but incorporation of the type of mesh was not disclosed. Then the relevant investigations were followed, that was decided by the surgeon and the attending anesthetist the eve before surgery. Patients were operated the most recent available list and during surgery an adequate overlap using a 15×15 cm mesh was used in all cases included in the study. The technique of fixation was documented and the total operative time was observed as was the actual time to fixation of the mesh, using Tacks (Protack R ).
Four surgeons, being informed about the study, operated on all the cases over this period; however prior to the beginning of the study they had had a minimum experience of performing 50 TAPP procedures. A proforma was prepared to record all the relevant data such as the NYHUS classification of type of hernia,  the postoperative pain scale score, and the complications that followed including seroma formation, testicular pain and atrophy, preoperative injuries, surgical emphysema, adhesion obstruction, mesh infection, wound infection, and perioperative mortality.
A planned questionnaire showing the frequency was obtained from all male patients depicting the sexual dysfunction following surgery. This included those patients with preexisting sexual dysfunction. The planned sequence of follow-up after discharge of patient was at 1 week, 1month, 3 months, 6 months, and one year.
Descriptive statistics were used for characterization of patient groups, presented as mean (SD) or median (range) depending on the type of data and distribution. The data were compared using Student's t test. Categorical data were presented as percentages with95 percent confidence intervals and compared using an χ2 test. A value of P< 0.050 was considered significant. The collected data were analyzed using SPSS R for Windows version 13.0.
| Results|| |
The study was conducted over a period of four years at the Lady Reading Hospital, Peshawar, taking into account the data of 192 patients that agreed to a laparoscopic procedure. Few patients were lost during the follow-up of those whose procedure could not be completed and were converted. These were replaced with patients to respective groups, and data regarding the excluded patients were not included in the below results.
Patients for the polypropylene group were insignificantly of a younger age group depicted by the standard deviation. Although patients were from a wider age range in the VYPRO II R group, the mean age was greater than in the first group of patients. (P=0.134)
To the surprise of many epidemiologists of the 192 patients only one was a female patient who presented with inguinal hernia. This patient had a unilateral hernia and was placed in the second group (P=0.112). The classification described by Nyhus was followed to exclude the confounding effects of the type of hernia on the outcome. By analyzing the overall data for the frequency of complications using tests for multivariate analysis the classification did not confound the existing results, yet interestingly the majority of the patients were of the indirect variant in both groups, but the VYPRO II R group had a greater number of direct hernias (38.5%). This favored lesser operative time and so was the case in this group. There were also 6 cases of recurrent hernias that were highly favorable as the repeat anterior procedure in a previously anterior approach could sacrifice many structures (P=0.88).
As discussed above the VYPRO II R group had a higher number of direct hernias and the operative time was also much less but this was not statistically significant (P=0.91). To minimize this confounding factor and following multivariate analysis the mean time to fixation of the mesh also revealed a statistically insignificant lesser time in the VYPRO II R group that was 19.5(+3.6). Whether this was secondary to a better handling technique on part of the surgeon or the pliability making handling easier is hard to analyze by the existing data.
The mean hospital stay was slightly higher in the polypropylene group but that was also not significant. This decision was based on the discretion of the attending or the operating surgeon (P=0.89) [Table 1].
There were no perioperative mortalities in our series and the overall frequency of complication was 28%. The frequency of seroma formation was higher in the polypropylene group (6.25%) and majority of these patients from both groups had larger scrotal hernias. Laving a large part of the sac and overzealous dissection saw a total of ten patients with this complication in this series (P=0.34). Repeated ultrasound of the scrotum failed to exhibit a decrease in testicular size. Most of the patients were from the lightweight polypropylene group and were statistically significant; although the pain was of a bother it did not compel the surgeons to advise a re-exploration (P=0.04) [Table 2].
With the improving techniques of high-level disinfection and the use of disposable instruments the earlier higher frequency of wound infection has been decreased but the figure of 3.12% in the polypropylene group is greater than the other group with a P value of 1.13. Most of these patients settled with empirical followed by sensitivity-based antibiotics but two patients, both from the polypropylene group, failed to settle and developed a chronic discharge from the port sites suggesting by hematological and sonological evidence of mesh infection. They were maintained over the one-year period without exploration and were referred to specialist centers in Karachi (P=0.06).
The most significant finding in this study was the frequency of chronic pain with a visual analogue score of >3(1-10) after the six-month period was significantly higher in the polypropylene group suggesting the scar residue effect for which the lightweight design was planned. It showed a discomfort to the patient (P=0.02). In the other group only 6 patients had similar complaints. Adhesion obstruction presented in two patients in both groups, although the overlying peritoneum was secured by surgeon choice majority were closed with intracorporeal continuous suturing technique with absorbable material (P=0.77).
Surgical emphysema was also observed in the lightweight polypropylene group in greater but insignificant frequency (3.12%), out of which one patient was sent to the intensive care unit for high readings on the capnograph and for ventilatory support. Recovery was made and the patient was rejoined at the general ward with some discomfort and a hospital stay of 6 days post-surgery was announced. He had a polypropylene mesh incorporated but this was a technical fault on behalf of the operating team not limiting to the desired CO 2 pressures (P=0.49).
The recurrence rate was comparable in both groups with 3 patients in group 2. This too was statistically insignificant. The operative notes revealed the method of fixation with fewer tacks applied and also a history of chronic cough that continued in the postoperative period. The patients were reassured and advised relevant inguinal approach surgery in the following weeks, this time outside the terms of the existing trial (P= 0.63) [Figure 1].
The mean pain scores being followed on the proforma for the desired timings at 24hours showed both groups with high pain scores controlled by oral diclofenac sodium and parenteral Tramadol. Their doses were not part of collection of the data. Although an early resumption to work was observed in both groups, a statistically significant number of patients had higher pain scores in the polypropylene group till the end of data collection at one year. This score was significant (P<0.05) at 3 months, 6 months, and one year. These figures can be explained by the number of patients presenting with chronic pain 6 months postoperatively in the polypropylene group (15.62%).
| Discussion|| |
With the advent of technology came the ever available choice of biomaterials, each limiting its role to procedures best suited in this era of minimal invasive surgery. Inguinal hernia as complicated as it has been has paved way to a level of recurrence approaching zero.  There has been a major turn from the conventional inguinal approach to the laparoscopic approach recently, yet the right material for the right procedure has been a matter of debate. This has commercially revolutionized the way surgeons approach to individual cases and the material to be used there in: the concept of replacing the formerly and still frequently used heavy weight meshes(e.g., PROLENE R) for the anterior or the posterior (laparoscopic) approach.
The types of hernias by the NYHUS Classification between both groups remain similar, although an insignificant higher frequency of direct hernias in group B and lower age group from group A was observed [Table 1]. Studies reveal the frequency of mean pain scores following the preperitoneal placement of heavy weight meshes to be significantly greater on the visual analogue score. A study reported by Bittner et al revealed visual analogue scores well decreasing after the TAPP procedure for inguinal hernia. But this study was not comparing the postoperative pain scores by comparing different biomaterials and their construct. Apart from that there was also an improvement of sexual activity following the procedure, which was statistically significant in his study (<0.05). This again creates an argument about the persistent testicular pain that exists in those patients with preoperative pain and those with no prior dysfunction. In our study the significant difference in the frequency of testicular pain in the lightweight polypropylene group cannot be ignored (8.33%).
In a study conducted by Schouten et al.  32.1% of patients had preoperative pain. Only 2.3% of patients with no history of preoperative pain experienced moderate to severe (VAS 4-10) pain postoperatively. Pain impaired sexual function in 16.3% patients preoperatively and in 4.7% patients postoperatively. The majority of patients who reported pain during sexual activity preoperatively (82.3%) had no pain postoperatively.
In a study conducted by Chowbbey  et al. the authors compared the lightweight version of the polypropylene mesh included in our study (ULTRAPRO R ) and was performed on 402 patients (191 in ultrapro and 211 in prolene group) with bilateral groin hernias who underwent endoscopic TEP groin hernia repair from March 2006 to June 2007. At 1-year follow-up, incidence in ultrapro versus prolene group for chronic groin pain was 1.6% versus 4.7% (P = 0.178) and recurrence was 1.3% versus 0.2% (P = 0.078).
In ultrapro versus prolene group, mean visual analogue score for postoperative pain at day 7 was 1.07 versus 1.31 (P = 0.00), mean return to normal activities was 1.82 versus 2.09 days (P = 0.00). These figures conclude the lesser pain frequency and earlier return to work but a not-significantly higher frequency of hernia recurrence. This was also part of our study design to compare two nonheavy construct with the other group including a partially absorbable mesh (VYPRO II R ) that had its absorbable component absorbed in some weeks following placement.
Lightweight meshes were first introduced in 1998 (Vypro) and their superiority over the heavyweight meshes is now widely accepted. These meshes have large pores (normally 3-5 mm) and a small surface area. They stimulate a reduced inflammatory reaction and, therefore, have greater elasticity and flexibility.  The addition of the absorbable segment does in its part decrease the strength of the construct but the technical factors are truly believed to play a part. Furthermore the safety of the mesh in an infected environment is truly the benefit and actually cost-effective considering the expense of these meshes (VYPRO II R ).
In a study conducted by Langenbach et al.  the authors investigated the impact of the structure and the amount of polypropylene (PP) mesh used in laparoscopic transabdominal preperitoneal hernioplastic (TAPP) on physical function and life quality. Whereas in our study the quality of life scores were not calculated as they were in the above study using SF-2. Patients with primary inguinal hernia who underwent TAPP were randomized for using a heavyweight (108 g/ m 2 ), double-filament PP mesh or a composite mesh (polyglactin and PP) (Vypro II) by the TAPP repair for inguinal hernia.
Recurrence rate (2.2% overall) during their 60-month follow-up was not significantly different between the groups. This was quite similar to the rates in our study that was 2.08%. This is in contradiction to the Chowbey et al. study where a weaker construct resulted in a higher frequency of recurrence. Apart from recurrence Langenbach et al. also revealed a lower frequency of pain in either group. The composite mesh does not provide an advantage concerning physical function or pain development in comparison to the multifilament, heavyweight, pure polypropylene mesh. Independently of which mesh was implanted 5% of patients are still suffering from discomfort after 5 years of the implantation. This is very different from our results using the visual analogue score for pain in our study showing significant difference in the long-term outcome and avoidance of the heavy scar theory placed by Schumpelick et al. 
Earlier studies have revealed that the extent of a foreign-body reaction largely depends on the type of alloplastic material introduced.  Absorbable meshes have been designed, e.g., polyglactin 910, which lose 50% of their mechanical stability within three weeks and are degraded within three months. A compromise taking advantage of both material properties has been developed in a composite mesh. These optimized meshes exhibit a diminished foreign-body reaction with improved biocompatibility.
| Conclusions|| |
No difference in the frequency of recurrence was observed over a one-year follow-up but significant pain scores were observed in the polypropylene group. Studies with longer follow-up to rule the rate of recurrence in composite meshes will determine its benefit over the lightweight polypropylene meshes.
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[Table 1], [Table 2]