Open Repair of Primary Versus Recurrent Male Unilateral Inguinal Hernias: Perioperative Complications and 1-Year Follow-up

Introduction The recommendation in the European Hernia Society Guidelines for the treatment of recurrent inguinal hernias is to modify the technique in relation to the previous technique, and use a new plane of dissection for mesh implantation. However, the registry data show that even following previous open suture and mesh repair to treat a primary inguinal hernia, open suture and mesh repair can be used once again for a recurrent hernia. It is therefore important to know what the outcome of open repair of recurrent inguinal hernias is compared with open repair of primary inguinal hernias, while taking the previous operation into account. Patients and methods In the Herniamed Registry, a total of 17,594 patients with an open primary or recurrent unilateral inguinal hernia repair in men with a 1-year follow-up were prospectively documented between September 1, 2009 and August 31, 2013. Of these patients, 15,274 (86.8 %) had an open primary and 2320 (13.2 %) open recurrent repair. In the unadjusted and multivariable analyses, the dependent variables were intra- and postoperative complications, reoperations, recurrences, pain at rest, pain on exertion, and pain requiring treatment. Results Open recurrent repair compared with the open primary operation is a significant influence factor for higher intraoperative (p = 0.01) and postoperative (p = 0.05) complication rates, recurrence rate (p < 0.001), and pain rates (p < 0.001). With regard to repair of recurrent inguinal hernia, previous open mesh repair was associated with the least favorable outcome, and with the highest odds ratio, for all outcome criteria. Open recurrent repair following previous endoscopic operation presented the least risk for postoperative complications, complication-related reoperations, and re-recurrences. The pain rates identified on follow-up after open recurrent repair were lower following previous open suture operation compared with following open and endoscopic mesh repair. Summary A significantly less favorable perioperative and 1-year follow-up outcome must be expected for open repair of recurrent inguinal hernia in comparison with open primary inguinal hernia repair. After open recurrent repair, the most favorable perioperative complication and recurrence rates were identified following previous endoscopic repair, and the lowest pain rates following previous open suture repair. Open recurrent repair following previous open mesh operation was associated with the highest risks for perioperative complications, re-recurrences, and pain.


Introduction
The recommendation in the European Hernia Society Guidelines for the treatment of recurrent hernias is to modify the technique in relation to the previous technique, and use a new plane of dissection for mesh implantation [1,2]. However, the registry data show that even following previous open suture and mesh repair to treat the primary inguinal hernia, open suture and mesh repair are used once again for a recurrent hernia [2], despite meta-analyses and systematic reviews having identified advantages for endoscopic repair [3][4][5][6][7]. For example, based on data from the Swedish Hernia Registry following previous inguinal hernia repair in Lichtenstein or plug technique, the recurrence was repaired in 32.9 % of cases once again in Lichtenstein technique, in 26.4 % in endoscopic technique, in 16.5 % as plug and patch procedure, in 13.8 % in open preperitoneal technique, and in 2.7 % of cases in suture technique [2]. That was no doubt due to the fact that the skill needed for endoscopic repair of recurrent inguinal hernias was not always assured. Where surgeons had used an open technique to repair 95 % of primary inguinal hernias, then more than 90 % of recurrences were also repaired using an open procedure [8]. That was also true when using mesh repair for the primary inguinal hernia operation [9]. Comparison of 75 recurrences with 287 primary inguinal hernias repaired in Lichtenstein technique identified a tendency toward better outcomes for primary inguinal hernia patients [10]. Accordingly, it is unlikely that in the future either the majority of recurrent inguinal hernias will be repaired in endoscopic technique following previous open suture or mesh repair. This means that it is all the more important to know the outcome of open repair of recurrent inguinal hernias compared with open repair of primary unilateral inguinal hernias in order to make patients aware of the corresponding risk during the informed consent discussion.
The heterogeneous nature of recurrent hernias makes controlled trials in this field difficult and time-consuming, particularly when the previous repair has to be taken into consideration [2]. Large national hernia registers are a valuable way of obtaining information on recurrent groin hernia surgery.
Based on data from the Herniamed Registry, this present paper now compares open repair of recurrent inguinal hernias with open repair of primary inguinal hernias. Only male unilateral hernias are taken into account. The target criteria used are the perioperative complications as well as recurrence and pain rates on 1-year follow-up.

Patients and methods
The Herniamed Registry is a multicenter, internet-based hernia registry [11] into which 425 participating hospitals and surgeons engaged in private practice (Herniamed Study Group) had entered data prospectively on their patients who had undergone hernia surgery. All postoperative complications occurring up to 30 days after surgery are recorded. On 1-year follow-up, postoperative complications are once again reviewed when the general practitioner and patient complete a questionnaire. This present analysis compares the prospective data collected for all male patients with a minimum age of 16 years, who had undergone elective primary or recurrent unilateral inguinal hernia repair using open mesh (Lichtenstein, Plug, Gilbert and TIPP) repair [12,13].
The dependent variables were intra-and postoperative complications rates, number of reoperations due to complications, as well as the 1-year results (recurrence rate, pain at rest, pain on exertion, and pain requiring treatment).
All analyses were performed with the Software SAS 9.2 (SAS institute Inc. Cary, NY, USA) and intentionally calculated to a full significance level of 5 %, i.e., they were not corrected in respect of multiple tests, and each p value B 0.05 represents a significant result. To discern differences between the groups in unadjusted analyses, v 2 test was used for categorical outcome variables, and the ANOVA (analysis of variance) for continuous variables.
To rule out any confounding of data caused by different patient characteristics, the results of unadjusted analyses were verified via multivariable analyses in which, in addition to primary or recurrent operation, other influence parameters were simultaneously reviewed.
To identify influence factors in multivariable analyses, the binary logistic regression model for dichotomous outcome variables was used. Estimates for odds ratio (OR) and the corresponding 95 % confidence interval based on the Wald test were given. For influence variables with more than two categories, one of the latter forms was used in each as reference category. For age (years), the 10-year OR estimate and for BMI (kg/m 2 ) the 5-point OR estimate were given. Results are presented in tabular form, sorted by descending impact.

Unadjusted analysis
Open recurrent repair was performed for 1011 (43.6 %) patients following previous open suture repair, for 897 (38.7 %) patients following endoscopic mesh repair, and for 412 (17.7 %) patients after open mesh repair of the primary inguinal hernia ( Table 1). The open procedures used for recurrent repair are shown in Table 2, together with the previous operation. Just as for the primary procedures listed here on the basis of the registry data, so too for recurrent repair was the Lichtenstein technique used most often, followed by the Plug, TIPP, and Gilbert techniques.
Significant differences were seen with regard to mean age and BMI between open repair of primary and recurrent inguinal hernias (Table 3). That was also true for the patient-related (Table 4) and risk factors ( Table 5). Highly significant differences (in each case p \ 0.001) were noted for the categorical influence variables, i.e., ASA score, hernia size, EHS classification, and risk factors (Table 4,5).
Unadjusted analysis identified a significantly higher value for recurrent repair with regard to almost all the target parameters, i.e., intraoperative complications, postoperative complications, complication-related reoperations, recurrences, pain at rest, pain on exertion, and pain requiring treatment on 1-year follow-up (Table 6). However, major differences were found in the recurrent repair results in relation to the previous operation. For example, in those cases where an open procedure was used for recurrent repair following endoscopic mesh repair in the primary operation, the intra-und postoperative complications, complication-related reoperation, and re-recurrence rates were comparable with those identified for open primary inguinal hernia repair.  Multivariable analysis

Intraoperative complications
The multivariable analysis results for the intraoperative complication rate are illustrated in Table 7 (model matching: p \ 0.001). The probability of onset of intraoperative complications during the primary and recurrent operations was significantly influenced by the risk factors (p = 0.01) and ASA score (p = 0.02). The presence of risk factors resulted in a significant increase in the intraoperative complication rate [OR = 1.534 (1.126-2.090)]. However, on comparing the implications of the various ASA scores, i.e., score II versus I and III/IV versus I, the higher scores were found to have exerted less influence on onset of intraoperative complications (Table 7). Open recurrent operations had a significant influence (p = 0.010), regardless of the previous operation, on the intraoperative complications compared with open primary operations. All recurrent operations were found to have negatively impacted onset of an intraoperative complication. The most negative influence was seen with an OR = 2.929 [1.515-5.664] with previous open mesh repair. The negative impact on the intraoperative complication rate was markedly less and comparable for previous endoscopic mesh repair and previous suture repair. In the open primary operations, too, the surgical technique had a significant influence (p \ 0.001) on the occurrence of intraoperative complications. Compared with the Lichtenstein operation, the impact of the Plug and Gilbert techniques on onset of an intraoperative complication was markedly less, while that of the TIPP procedure was somewhat less.

Postoperative complications
The multivariable analysis results for the postoperative complication rate are shown in

Complication-related reoperation
The multivariable analysis results for the complicationrelated reoperation rate are given in    Recurrence Table 10 shows the multivariable analysis results for factors impacting recurrence on 1-year follow-up (model matching: p \ 0.001). This was influenced essentially by the operation type (p \ 0.001). Conduct of a recurrent operation resulted in a significantly higher risk of re-recurrence in comparison with an open primary repair of an inguinal hernia. That was true for each type of previous operation, albeit considerable differences were seen here. For example, whereas the probability of re-recurrence following previous endoscopic repair was only slightly higher than the risk posed by an open primary operation, the probability of re-recurrence associated with open   (4.240-11.662), was considerably higher. Likewise, BMI had a highly significant impact on the recurrence rate on follow-up (p \ 0.001). Accordingly, patients with a 5-point higher BMI had a higher recurrence rate ]. Higher age also gave rise to a higher recurrence risk (10 year OR = 1.170 [1.027-1.333], p = 0.02). For the primary operations, too, significant differences were found in the recurrence risk in relation to the surgical technique used (p = 0.02). For example, the risk of recurrence was lower following the Gilbert, Plug, and TIPP surgical procedures compared with the Lichtenstein operation.

Pain at rest
The multivariable analysis results for pain at rest on 1-year follow-up are summarized in In the primary operations, too, significant differences (p \ 0.001) favorable to the Gilbert, Plug, und TIPP procedures were seen compared with the Lichtenstein operation.
Pain on exertion Table 12 shows the multivariable analysis results for pain on exertion on follow-up (model matching: p \ 0.001). As for pain at rest, pain on exertion also occurred more often after recurrent operations and in patients with higher BMI (in each case p \ 0.001). For the recurrent operations, the risk of that happening also depended on the previous operation. Compared with primary operation, the risk of onset of pain on exertion following recurrent repair was higher when endoscopic repair [OR   (Gilbert, Plug, and TIPP) used as an alternative to the Lichtenstein operation was analyzed.
As regards the intraoperative complication rate, multivariable analysis demonstrated that the recurrent operation was an independent influence factor for onset of intraoperative complications. That impact was least favorable following not only previous open mesh operation, but was This trend is also reflected in the complication-related reoperation rates.
The impact of recurrent inguinal hernia repair compared with primary operation is particularly pronounced with regard to the recurrence and re-recurrence rates. Here, too,  Here one would have expected that the risk would be lower after previous endoscopic operation since repair is carried out in a new plane of dissection. However, here previous open suture repair presented the least risk for occurrence of pain after open recurrent repair.
For the findings presented here, one must also take into account that analysis of open primary inguinal hernia operations also revealed significant differences in the results obtained for the various surgical techniques. For example, multivariable analysis identified significantly better results for the open Gilbert, Plug, and TIPP techniques compared with the Lichtenstein operation.
In summary, analysis of the data from the Herniamed Hernia Registry as presented here demonstrates that, taking into account all other influence factors, open recurrent repair compared with open primary inguinal hernia repair is associated with a significantly poorer perioperative and 1-year follow-up outcome. However, relevant differences were identified in relation to the technique employed for the primary operation, and to the type of operation used prior to recurrent repair. The data presented here confirm the recommendation given in the Guidelines of the European Hernia Society to use open repair in a new plane of dissection for recurrent repair following previous endoscopic repair of a primary inguinal hernia. The results demonstrate that the risk for onset of a postoperative complication, complication-related reoperation, and re-recurrence is comparable with that presented by the primary operation. Open recurrent repair after previous open mesh repair posed the highest risk for occurrence of intraoperative and postoperative complications, complicated-related reoperations, re-recurrences, pain at rest, pain on exertion, and chronic pain requiring treatment. Therefore, the recommendation in the Guidelines of the European Hernia Society should definitely be observed for recurrent repair following previous open mesh repair.
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