Wound Healing Post-mesh Repair ― An Observational Study

Several techniques of inguinal hernia repair have been done over the years to achieve a faster healing outcome (Amato et al. 2009; Kark et al. 1998). In Sri Lanka, surgical mesh repair such as: (1) open repairs (Anterior, Lichtenstein, Desarda, and Guamieri (which are tension-free), and Bassini and Shouldice (with tension), and (2) laparoscopic mesh repairs are usually used (Amato et al. 2009; Aufenacker et al. 2004; Vrijland et al. 2002; O’Dwyer et al. 2004). Wound healing regardless of the techniques for mesh repair varies on the types of meshes and methods (O’Dwyer et al. 2004; Bilsei 2012). Biological mesh types (Bilsei 2012) in Table 1 are ideally used in Sri Lanka, however, not observed in this study.


Aims
On account of these issues, it was hoped that: 1. Identify the best surgical mesh repair techniques for inguinal hernias; and 2. Identify prevalences of wound healing post-mesh repair.

Variables
The cause variable was the surgical mesh repair procedure among patients with an inguinal hernia while the effect variable was the healing time.The variables would then answer the question: Was there a significant evidence of faster wound healing time for post -mesh repair among adult patients with an inguinal hernia?

Hypothesis
It was however hypothesized that there is an important technique of surgical mesh repair leading to a faster wound healing time among patients with an inguinal hernia admitted to government hospitals in the eastern province of Sri Lanka.

Search strategy
Review of literature of the publications relating to the fast wound healing of inguinal hernia post mesh repair among adult patients came from the published reports of the Ministry of Health, Sri Lanka, the published annual reports of the Central Bank, the documents of the

Critical Appraisal
Three hundred patients were studied by Vrijland et al. (2002) between September 1993 and January 1996.Based on all patients scheduled for repair of a unilateral primary inguinal hernia were randomized to non-mesh or mesh repair.The patients were followed up at one week and 1, 6, 12, 18, 24 and 36 months.Clinical outcome, such as quality of the mesh, its weight and stiffness and isotropy were analyzed.The results were to compare mesh and non-mesh suture repair of primary inguinal hernias on quality of mesh in a multi-center randomized trial in general hospitals.The result of the study of Vrijland et al. (2002), says that 300 patients healed after a 3-year recurrence rate: 1% for non-mesh repair (n = 143) and 7% for mesh repair (n = 146) (p = 0•009).Mesh repair with quality meshes was superior to non-mesh repair.
On the other hand, O'Dwyer et al. ( 2005) conducted a study aimed to compare the pain of any severity at 12 months after inguinal hernia repair with a partially absorbable lightweight (LW ) mesh group or with a non-absorbable heavy weight (HW) mesh group.They used 321 patients, 162 in the LW group and 159 in the HW group and patients were assessed for pain at 1, 3 and 12 months by questionnaire, and were examined clinically at 12 months.O' Dwyer et al. (2005) found after 12 months, significantly fewer patients in the LW group than in the HW group had the healing time of 39.5% versus 51.6% (difference -12•1 (95% The recurrence of inguinal hernia rate was higher in the LW group (5.6% versus 0.4%; p=0•037).Five of 8 recurrences in LW group were associated with a single participating center.Finally, O'Dwyer et al. (2005) has taken a decision that the "use of LW mesh was associated with less chronic pain but an increase in hernia healing time post-mesh hernia repair.The latter may be related to technical factors associated with fixation of such meshes rather than any inherent defect in the mesh".
Re-operation after recurrent groin hernia repair was the study done by Haapaniemi et al. (2001) analyzing re-operation rates for recurrent and primary groin hernia repair documented in the Swedish Hernia Registration from 1996 to 1998.Postoperative complications and direct hernia were associated with its burst strength which increased relative risk for re-operation.Actuarial analysis adjusted for patients' death was used for calculating the cumulative incidence of re-operation.Haapaniemi et al. (2001) found that from 1996 to 1998, 17 985 groin hernia operations were recorded in the Swedish Hernia Registration, 15% for a recurrent hernia and 85% for a primary hernia.At 24 months the risk for having a re-operation was 4.6% after recurrent hernia repair and 1.7% after primary hernia repair.The relative risk for re-operation was significantly lower for laparoscopic methods and anterior tension-free repair because of the significant burst strength of the meshes.
The study of Aufenacker et al. (2004) aimed to determine whether the use of prophylactic antibiotics are effective in the prevention of postoperative wound infection after Lichtenstein open mesh inguinal hernia repair.Patients with primary inguinal hernia scheduled for Lichtenstein repair were randomized to a preoperative single dose of 1.5 g intravenous cephalosporin or a placebo.Patients with recurrent hernias, immunosuppressive diseases, or allergies for the given antibiotic were excluded.Aufenacker et al. (2004) found that 1008 patients analyzed had infections (1.6%) in the antibiotic prophylaxis and the placebo group (p = 0.82).There were deep infections (1.8%) in the antibiotic prophylaxis group and the placebo group (p = 0.57).Statistical analysis showed an absolute risk reduction of 0.19% (95% confidence interval, −1.78% to 1.40%) and a number needed to treat of 520 for the total number of infections.For deep infections, the absolute risk reduction is 0.20% (95% confidence interval, −0.87% to 0.48%) with a number needed to treat of 508.Aufenacker et al. (2004) concluded that a low percentage of wound infection after Lichtenstein open mesh inguinal (primary) hernia repair was found, and there was no difference between the antibiotic prophylaxis or placebo group.The result showed that, in Lichtenstein inguinal major hernia repair, antibiotic prophylaxis is not indicated in low-risk patients but rather the tensile strength and compliance of the mesh.

Data Collection
The questionnaires were issued directly to 120 inguinal hernia patients who were admitted to two government hospitals.
The questionnaire was in the form of a constructed survey based on the Likert fivepoint scale (Strongly Agree, Agree, Neutral, Disagree and Strongly Disagree).According to Hopkins (2008), validity as an indicator of research measures the questionnaires set.According to Johns (1999), questionnaires must have greater validity if they consider the ease of its use.

Data Analysis
The results from the data analysis included an analysis of response rate, demographic characteristics of respondents, about their disease, symptom of disease and healing time after surgery.The analysis was further divided into sections: (1) exposure to surgical mesh repair of an inguinal hernia; and (2) evidence of wound healing regardless of the surgical technique.
The descriptive data results used central tendencies such as: • Mean and standard deviation; • Anova test; and • Probability findings.

Ethics
The approval started with the ethical committee of Lincoln University College, Research Management.The Sri Lankan Ministry of Health also approved the use of the government hospitals for data collection.Lastly, letters from the two government hospitals selected were sought.from the meshes and no cases of unhealed wounds post-mesh repair.The incidence of deep infection was 0.3%.However, n o cases of testicular atrophy occurred.There was a gradual decrease in time of return to work over four successive 1-year periods.Manual workers returned to work in 15 days (median) in the first year, reducing to 9 days in the fourth year.The overall median time of performance to work across the whole group was nine days.There were eight recurrences with an 18-month to 5-year follow-up.Allan et al. (1998) conclude d from this study that "open mesh repair under local anesthesia is an effective day case technique, particularly in the elderly and medically unfit.The economic benefits are enhanced by low morbidity, early return to normal activities and low recurrence rates".

Analysis
The literature reviewed will help design the method of this research (Hopkins 2008).It was also examined that there were varieties of terms that needed to be observed and variables that affected the healing time.Moreover, surgical methods of mesh repairs are based on the physical characteristics of the meshes (Bilsei 2012).Surgical techniques are still considered.However, these methods would fail if the quality of the meshes was not considered (Table 2).

Design
A quantitative cross-sectional study design was used in this research.This was because two hospitals were selected to cross analyze the data collected from the samples.

Sampling Technique
Cluster random sampling used 120 populations; at 20% estimated prevalence and precision of 5% margin of error at 95% confidence interval.The sample size was calculated using this formula: Tables 2 and 3 shows that the vast majority of the respondents regardless of age group, healed post-mesh repair (p<0.05).
However, on Table 4 ages 30-39 faced low impact with mesh repair (p = 0.4393), while ages 40-49 were also probable to have longer healing time (p = 0.3947).These age brackets (30-49 years old) were facing pain or discomfort in their groin, especially when bending over, coughing or lifting.
Table 5 on the other hand, identifies the number of respondents admitted for a re-occurrence of the hernia thus subject for second mesh repair.A 6.7% (n = 8) previously had hernia repair ≥1 year while 93.3% (n = 112) only had one-time experience of mesh repair.Table 6 shows the symptoms of postmesh repair.The µ within the range of ≥1 to ≤ 2.5 indicates that all the symptoms had no impact on the healing time of post-mesh repair.Recovering period among symptoms differed significantly using F-test (s = 0.862), on pain or discomfort, especially when bending over, coughing or lifting symptom.The F-test significant value (4115) = 0.719, for the rest of the symptoms except serious mesh repair pain was not statistically significant at 0.05.Serious mesh repair pain (p<0.05) did influence the longer recovery period for post-mesh repair.Other symptoms such as irregular bowel (p = 0.3736), blood in stool (p = 0.3567), black tiny stool (p = 0.2392), and pain on exertion (p = 0.3579) were not significant.Age bracket 30-39 years old (p = 0.4393) and 40-49 (p = 0.3947) had more problems with recovery as compared with the other age brackets since they were facing pain or discomfort in their groin, especially when bending over, coughing or lifting.

CONCLUSION
Of the 120 respondents, 82.5% (n = 99) healed while 17% (n = 21) had recurrence of hernia.There was no significant technique of surgical mesh repair leading to a faster wound healing time among patients with an inguinal hernia admitted to government hospitals in the eastern province of Sri Lanka.However, 48.3% preferred anterior tension-free and 49.2% said that Lichtenstein tension-free mesh repair healed faster.Nevertheless, 2.5% of the total respondents said that a hernia healed after one month but <2 months; and 97.5% respondents stated that they recovered in less than one month regardless of the surgical mesh repair techniques they had.

RECOMMENDATION
Prophylactic antibiotics could be used with the high rate of wound infection post-surgical mesh repair irrespective of the technique (Praveen & Rohaizak 2009).Local anesthesia is a suitable and economical option for extensive repairs and should be popularized in day-case settings (Simons et al. 2009).Mesh repairs are superior to "non-mesh" tissue-suture repairs in Sri Lanka.Lichtenstein repair and endoscopic/ laparoscopic techniques have similar efficacy (Akinci et al. 2010;Khajanchee et al. 2004;McCormack et al. 2005 ) however, only tensionfree (Lichtenstein) is the preferred technique of Sri Lankans.Standard polypropylene mesh was still the choice, whereas the use of partially absorbable lightweight meshes seemed to have some advantages.
According to the data analysis, mesh repair of inguinal hernias was superior to non-mesh repair and showed comparable results regarding postoperative complications, pain, and quality of life.However, quality of meshes (Table 7) could also affect healing time and was therefore recommended to surgeons for further research.Dimensional decrease in length or width delays healing time (Allan et al. 1998) Deformation of a material in response to an applied force delays healing time (Allan et al. 1998) Maximum stress subject to its load that can withstand stretching without tearing or breaking speeds up healing time (Aufenacker et al. 2004) The maximum uniformly distributed pressure applied at right angle to its surface that will withstand under standardized conditional pressure speeds up healing time (Haapaniemi et al. 2001) Changes its shape and size under the action of opposing forces, but recovers its original configuration when the forces are removed, increases healing time (Allan et al. 1998) Ratio of steadily increasing or decreasing force acting on a deformable elastic material to the resulting displacement or deformation speeds up healing time (Vrijland et al. 2002) Displacement or deformation of a material as the result of application of a unit force affects healing time (Aufenacker et al. 2004) When a material do not exhibit differences in properties based on the direction of the applied load, affects healing time (Vrijland et al. 2002)

Finally,
Allan et al. (1998) a imed to study the "Controversy existing over the relative advantages of open mesh repair compared with open stitching methods and the laparoscopic approach."Allan et al. (1998) examined 2906 consecutive unselected adult patients who underwent 3175 primary inguinal hernia repairs using polypropylene mesh, analyzing its elasticity on an ambulatory basis.The age range was 15-92 years.The study specifically investigated the postoperative course about pain, complicati ons, and time of return to work.Allan et al. (1998) found that there were neither shrinkages nor deformations with strains where, n = population; Z = confidence P = prevalence, and d = precision.

Table 1 .
Types of biologic meshes

Table 2 .
Prevalence of healing post mesh-repair.

Table 4 .
Mesh repair healing time by age group.

Table 6 .
Symptoms of post-mesh repair.

Table 7 .
Quality of meshes for further research.