TEP or TAPP for recurrent inguinal hernia repair—register-based comparison of the outcome

Introduction The guidelines of the international hernia societies recommend laparo-endoscopic inguinal hernia repair for recurrent hernias after open primary repair. To date, no randomized trials have been conducted to compare the TEP vs TAPP outcome for recurrent inguinal hernia repair. A Swiss registry study identified only minor differences between the two techniques, thus suggesting the equivalence of the two procedures. Materials and Methods Between September 1, 2009 and August 31, 2013 data were entered into the Herniamed Registry on a total of 2246 patients with recurrent inguinal hernia repair following previous open primary operation in either TAPP (n = 1,464) or TEP technique (n = 782). Results Univariable and multivariable analysis did not find any significant difference between TEP and TAPP with regard to the intraoperative complications, complication-related reoperations, re-recurrences, pain at rest, pain on exertion, or chronic pain requiring treatment. The only difference identified was a significantly higher postoperative seroma rate after TAPP, which was influenced by the surgical technique, previous open primary operation and EHS-classification medial and responded to conservative treatment. Conclusion TEP and TAPP are equivalent surgical techniques for recurrent inguinal hernia repair following previous open primary operation. The choice of technique should be tailored to the surgeon’s expertise.

complication rates, complication-related reoperation rates, and higher pain and recurrence rates (4).
In the meta-analysis, only joint comparison of the two laparo-endoscopic techniques (TEP, TAPP) with the open Lichtenstein technique was performed. There was no high risk of bias in any of the included trials (8). The meta-analysis by Pisanu et al. (8) detected for laparoendoscopic repair of recurrent hernias a significantly lower chronic pain rate and significantly earlier resumption of normal everyday activities. Compared with the Lichtenstein operation, the operative time for laparoendoscopic procedures was significantly longer (8). On the basis of the meta-analyses, the European Hernia Society recommends laparo-endoscopic inguinal hernia repair for recurrent hernias after conventional open repair (10,18). No distinction is made here between the laparo-endoscopic TEP and TAPP techniques.
To date, no randomized trials have been conducted to compare the TEP vs TAPP outcome for recurrent inguinal hernia repair following previous open repair. A Swiss registry study (19) compared the outcome of a total of 1309 laparo-endoscopic recurrent operations, of which 1022 used the TEP technique and 287 the TAPP technique. A significantly higher intraoperative complication rate and longer operative time was identified for the TEP group. The postoperative length of hospital stay was longer for patients undergoing TAPP (19). Surgical postoperative complications, general postoperative complications, and conversion rates were not significantly different (19). The authors concluded that the absolute outcome differences are small and that both techniques appear to be safe and effective for patients undergoing laparo-endoscopic repair for unilateral recurrent inguinal hernia (19).
Based on data from the Herniamed Registry (20), the present analysis now compares the outcome of elective laparo-endoscopic recurrent unilateral inguinal hernia repair in men following previous open operation.

Patients and methods
The Herniamed Registry is a multicenter, internet-based hernia registry (20) into which 427 participating hospitals and surgeons engaged in private practice (Herniamed Study Group) have entered data prospectively on their patients who had undergone hernia surgery. All postoperative complications occurring up to 30 days after surgery are recorded. On one-year follow-up, postoperative complications are once again reviewed when the general practitioner and patient complete a questionnaire. They are also asked about any re-recurrence, pain at rest, and on exertion as well as pain requiring treatment. This present analysis compares the prospective data collected for all male patients with a minimum age of 16 years who had undergone elective recurrent unilateral inguinal hernia repair using either transabdominal preperitoneal patch plasty (TAPP) or total extraperitoneal patch plasty (TEP).
The majority of primary unilateral repairs in the Herniamed Registry have been performed as open mesh repair (Lichtenstein) with 32.5% and laparo-endoscopic mesh repair (TAPP, TEP) with 49.9%. Non-mesh repairs (Shouldice, Bassini) in primary unilateral inguinal hernia repair in the Herniamed Registry make only a contribution of 4.7% of all cases.
The dependent variables were intra-and postoperative complication rates, number of reoperations due to complications as well as the one-year results (re-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 ≤ 0.05 represents a significant result. To discern differences between the groups in unadjusted analyses, Fisher's exact test was used for categorical outcome variables, and the robust t test (Satterthwaite) for continuous variables.
To rule out any confounding of data caused by different patient characteristics, the results of unadjusted analyses 1 3 were verified via multivariable analyses in which, in addition to TEP or TAPP 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 case 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 were presented in tabular form, sorted by descending impact.
No significant difference in mean age and BMI was found between the recurrent operations in TEP and TAPP technique ( Table 2). That was also true for the ASA-score, defect size, and risk factors (Table 3). With regard to EHS localization, there were significantly more medial recurrent inguinal hernia defects (52.2% vs. 44.8%; p < 0.001) and significantly fewer lateral defects (55.4% vs. 68.8%; p < 0.001) in the TAPP group ( Table 3).
As regards the target parameters, no differences were found between TEP and TAPP recurrent inguinal hernia repair in the intraoperative complications (Table 4). For the postoperative complications, significantly lower values (1.7% vs. 4.6%; p < 0.001) were identified for TEP, but that was mainly due to the difference in the seroma rate (0.5% vs. 3.2%; p < 0.001) ( Table 4).
However, since this did not result in any difference in the complication-related reoperation rate, it only meant that TAPP was associated with a higher seroma rate, which responded to conservative treatment.
On one-year follow-up no differences were detected in the re-recurrence rate after recurrent inguinal hernia repair following TAPP and TEP, or in the rates of pain at rest, pain on exertion, or chronic pain requiring treatment (Table 4).

Multivariable analyses
For the intraoperative complications, complication-related re-reoperations, and recurrences on follow-up it was not possible to calculate a valid model since the number of positive cases was too small.

Postoperative complications
The results of the model that explored how the variables related to patient and operation characteristics (surgical technique, previous open primary operation, age, BMI, ASA-score, defect size, and defect localization as well as the presence of risk factors) impacted onset of postoperative complications are illustrated in Table 5 (model matching: p < 0.001).
The postoperative complications, primarily seromas, were affected by the surgical technique. Conduct of TAPP operation (OR = 3.010 [1.636; 5.538

Pain at rest
The results of multivariable analysis of pain at rest are presented in Table 6 (model matching: p = 0.009). Here BMI was the only influence factor identified (p < 0.001).

Pain on exertion
The results of multivariable analysis of pain on exertion are shown in

Chronic pain requiring treatment
The results of multivariable analysis of chronic pain requiring treatment are presented in  repair having impacted the rate of chronic pain requiring treatment.

Discussion
In the Guidelines of the European Hernia Society (EHS) and the International Endohernia Society (IEHS), TEP and TAPP are recommended as equivalent procedures for recurrent hernia repair following the previous open mesh and suture repair of primary inguinal hernias (1,10,18). To date, no prospective randomized trials have been conducted to compare TEP and TAPP for recurrent inguinal hernia repair following previous open primary repair. A Swiss registry study that compared laparo-endoscopic recurrent hernia operations identified a significantly higher intraoperative complication rate and longer operative time for TEP operations, which were much more common than TAPP procedures in the patient group analyzed (19). The postoperative length of hospital stay was longer for patients undergoing TAPP (19). Surgical postoperative complications, general postoperative complications, and conversion rates were not significantly different (19). The authors concluded that the absolute outcome differences are small  and that both techniques appear to be safe and effective for patients undergoing laparo-endoscopic repair for unilateral recurrent inguinal hernia (19). Likewise, the present analysis of data from the Herniamed Registry, in which the proportion of TAPP operations was higher than that of the TEP operations, revealed similar outcomes for the laparo-endoscopic recurrent operations following previous open primary operation. Based on the Herniamed Registry data, no significant differences were found between the recurrent operations in TEP vs TAPP technique with regard to the intraoperative complications, complication-related reoperations, re-recurrence rates, rates of pain at rest, pain on exertion, or chronic pain requiring treatment. Unfavorable results were identified only with regard to the higher seroma rates associated with TAPP; these responded to conservative treatment. The influence variables identified here on multivariable analysis were, in addition to the surgical technique, the previous open primary operation and the EHS-classification medial. A previous open primary suture repair has a higher risk for development of a postoperative complication as a previous open primary mesh repair and the EHS-classification medial a lower risk. The results of multivariable analysis of the other parameters did not find any evidence of any impact exerted by the surgical technique.
Accordingly, this analysis of data from the Herniamed Registry corroborates the findings of the Swiss registry study. Similarly, the Herniamed Registry did not detect any significant differences between TEP and TAPP for recurrent unilateral inguinal hernia repair in men following previous open suture or mesh primary operation. That was true for the intraoperative complications, complication-related reoperations, re-recurrence, pain at rest, pain on exertion, and chronic pain requiring treatment on one-year followup. The only difference was that TAPP was associated with a higher seroma rate, which responded to conservative treatment. There was no difference in the other postoperative complications between TEP and TAPP for recurrent repair.
In summary, both TEP and TAPP can be recommended as effective techniques for treatment of recurrent inguinal hernia following previous open primary operation. The decision to use one or the other technique should be based solely on the surgeon's expertise. The registry study presented here thus confirms the recommendations in the guidelines on laparo-endoscopic treatment of recurrent inguinal hernia following previous open primary operation.