Inflammatory response to open tension-free inguinal hernioplasty versus conventional repair

LETTERS TO THE EDITOR INFLAMMATORY RESPONSE TO OPEN TENSION-FREE INGUINAL HERNIOPLASTY VERSUS CONVENTIONAL REPAIR To the Editor: We read with great interest the article written by Gu¨rleyik et al.1 We have some concerns about the study they carried out. The study was not randomized. The first 16 patients were treated with tension-free and the following patients with conventional repairs. Randomization improves the chance that the probabilities obtained from statistical tests will be valid.2 The mean values were given in Tables I and II. It was not obvious whether the values following the mean were standard deviation (SD) or standard error of mean (SEM). Also, there was no need to use two different measures of dispersion (SD or SEM and range) at the same time. The authors reported that cytokine response increases with age and magnitude of the procedure. Comparing pediatric patients in group 1, with no reinforcement of posterior wall, with the adult patients in groups 2 and 3 showed the reported significant differences in mean serum IL-6 levels, which is easy to understand. Group 4 (control) consisted of 10 healthy adult volunteers without any operation. The control subjects should be chosen to match individual cases for certain characteristics, such as age and gender.2 Although age ranges were similar in adult groups, the gender of the patients in group 4 was not given. If the control group was simply used to measure the reference ranges of IL-6 and C-reactive protein (CRP) in the sample population, those healthy volunteers would seem to be cooperative colleagues in the authors’ clinic, at the mean age of 53.9 ⫾ 15.6 years. Turkey may have a smaller mean age value. The mean CRP value in group 4 was measured 7.5 ⫾ 4 (2–14) mg/L. If the data following the mean value were reflecting the SD, then the normal range (mean ⫾ 2 SD) would be between ⫺0.5 and 15.5 mg/L. Whether SD or SEM, a normal distribution cannot be assumed, since a negative value for 76

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CRP is not possible.2 It was also written that the reference range of the laboratory was between 0 and 6 mg/L, which is lower than the values found in group 4. The serum levels of IL-6 and CRP did not seem to be precisely or sensitively measured. We believe that randomizing the patients, performing the same type of conventional operation, and leaving groups 1 and 4 out of the study would give more significant results. Mehmet Ku¨rt¸at Bozkurt, MD Division of General Surgery Isparta State Hospital Fatih Ag˘alar, MD Argun Akc¸akanat, MD Department of General Surgery Suleyman Demirel University School of Medicine Isparta, Turkey 1. Gu¨rleyik E, Gu¨rleyik G, C¸etinkaya F, U¨nalmis¸er S. The inflammatory response to open tension-free inguinal hernioplasty versus conventional repairs. Am J Surg. 1998;175:179 –182. 2. Campbell MJ, Machin D. Medical Statistics. A Commonsense Approach. West Sussex, England: John Wiley & Sons; 1993.

The Reply: We thank Dr. Bozkurt et al for their interest on our manuscript. As mentioned in the manuscript, we had planned prospectively to take the first 16 consecutive patients with indirect inguinal hernia for tension-free and the following 20 patients for conventional repairs. The presence of inguinal hernia was the only factor for selection of these 36 patients for the surgical treatment of their disease. We did not use further selection criteria for forming our two groups. We do not believe that this selection affects the validity of statistical analysis of our results. The data were statistically analyzed using a computer program. Results were presented as mean and standard deviation. The range of our measurements was also presented for each variable in the two tables. Serum Il-6 measurement is not a routine test. A control group consisting of 10 healthy adult men was formed for determining the normal reference value. We disagree with Dr. Bozkurt et al about the mean age of this group. We were easily able to find

10 healthy adult men with a mean age of 54 years. We do not understand why they have some doubt about the mean age of this control group. The serum levels of Il-6 and C-reactive protein were sensitively measured with precise methods described in the Patients and Methods section, by a specialist who is a coauthor of our manuscript. All the measured values were written in a computer program, and analyzed for statistical significance. Dr. Bozkurt et al have suggested performing the same type of conventional operation. In our study, we chose to perform the three most common types of inguinal hernia operations for conventional repair group. As proposed by Dr. Bozkurt et al, similar studies could also be carried out performing only a single type of conventional operation. Dr. Bozkurt et al have also proposed that we leave groups 1 and 4 out of the study. We do not agree with them. In this study, we also tried to determine the effect of posterior wall repair on the stress response. A group of hernia repairs without reinforcement of the posterior wall was needed for the comparison. Pediatric hernia patients (group 1) offered the only possibility to form such a group for this purpose. We appreciate the opportunity to respond to this critique. Emin Gu¨rleyik, MD Istanbul, Turkey

LATE INFECTION AFTER MESH-PLUG INGUINAL HERNIOPLASTY To the Editor: We read with interest the article by Mann et al (Am J Surg. 1998;176:12– 14) about late-onset deep prosthetic infection following mesh repair of inguinal hernia. We report here a case of late onset prosthetic infection after mesh-plug inguinal hernioplasty1 and our treatment of this complication. A 47-year-old man had a right-sided direct inguinal hernia. We performed inguinal hernioplasty using mesh and a plug in July 1998. He was discharged from our hospital 7 days later without any wound infection. He presented again complaining of right in0002-9610/00/$–see front matter PII S0002-9610(99)00249-4