There are thousands of patients who have had the ONSTEP procedure with the Polysoft mesh. In the Polysoft mesh the ring is non-absorbable and if the patient is skinny, there may be complaints from the lateral part of the mesh where the ring will lie close to the skin. In such a case we usually recommend that the patients should wait for 6 months in order for the mesh to be fully integrated into the tissue, especially in the preperitoneal position and on the muscle plate between the two aponeuroses. Then the patient is offered a small reoperation where an incision of about 1 cm is performed on top of the palpable part of the ring corresponding to the lateral part of the mesh. Then the two ends of the ring are dissected and cut and the ring can be withdrawn in full. We have made a video clip of this procedure [8]. Usually after ring removal the patient will have no complaints.

Some surgeons may have concern about how to repair a recurrence after previous ONSTEP repair, because the mesh will be present both preperitoneally as well as between the two aponeuroses laterally. It is, however, no problem at all to do a recurrence repair after a previous ONSTEP. It may preferably be done by two different approaches, one being a simple re-ONSTEP procedure, and the other by laparoscopic operation. If doing a re-ONSTEP then you dissect on top of the previously placed mesh, with dissection between the mesh and the pubic bone making a new space for a new Onflex mesh. A mesh is then placed between the old mesh and the pubic bone without removing any part of the old mesh. With a laparoscopic repair we use the transabdominal preperitoneal (TAPP) approach and it has been easy to take down the peritoneum from inside and then simply put a standard flat mesh in the preperitoneal space as a standard TAPP procedure.

The first clinical data regarding the ONSTEP technique is a large and impressive series of patients from two centers. The inventors presented 693 patients operated with the technique and followed up for one year [1]. Several findings from this paper showed a promise of a better open technique. Firstly, the degree of pain was very low, and none of the patients had chronic pain at one-year follow-up. Secondly, only four recurrences (0.6%) were found with three of them being in women. This has led the inventors to slightly modify the technique for female patients. Third, a very short duration of surgery — mean (SD): 17 (6) minutes — was found, which can be cost-saving for a department since it will allow for more patients being operated in one day. Such a large series with promising results called for further scientific exploration of the technique and also justified the conduction of randomized controlled trials. Surgeons from other countries in Europe visited the inventors, learned the technique, and started operating at their own centers.

The first published results from outside Portugal were from Denmark and included 80 patients, with follow-up by standardized questionnaires [9]. Results were good, albeit with the use of questionnaires and not a dichotomous pain registration some patients were found to have pain, but at very low levels. Later, results were presented from a series from Greece [10]. Results were still similar, with low levels of postoperative pain and no patients with chronic pain. A similar report was published from the Czech Republic [11], still with promising results (Table 8.1).

The non-controlled series outside the departments of the inventors supported the promising results, but are all at risk of bias since no randomization and/or control group was added to any of the studies. Furthermore, follow-up time and methods were not standardized. Therefore, there was a need for randomized clinical trials. As of December 2015, two prospective trials can be found on the WHO trial search portal [12]. Both studies are from Denmark. One is the ONSTEP versus Lichtenstein (ONLi) study, with 290 included patients and one-year follow-up [5]. The other, ONSTEP versus Laparoscopy (ONLap), is still recruiting patients [13]. Both studies are being conducted as multicenter studies with general surgical departments, i.e. not specialized hernia centers.

The early results from the ONLi trial demonstrated a safe implementation of the technique, with results similar to the Lichtenstein technique [13]. The only significant difference found in the early results was the duration of surgery. Patients were followed up with several questionnaires and at 6-month follow-up a significant difference was found, favoring the ONSTEP technique in the number of patients experiencing pain during sexual activity [14]. Follow-up for pain at 6 and 12 months showed that the number of patients with non-sexual pain as well as the intensity of pain were similar in the two groups. A noteworthy finding was that two patients in the Lichtenstein group experienced disabling chronic pain after surgery. Both had the mesh surgically removed as well as neurectomy conducted around 6 months postoperatively with complete resolving of pain for one patient but persisting pain for the other. No patients in the ONSTEP group experienced these disabling symptoms.

The ONLap study is designed to show non-inferiority between the ONSTEP and the laparoscopic technique (TAPP), i.e. similar levels of postoperative pain. The rationale is that the ONSTEP technique has some advantages compared to laparoscopy and therefore if non-inferiority can be demonstrated regarding pain other advantages will justify it as a valid alternative. The advantages are that the ONSTEP technique has a shorter duration of surgery, it does not require the same expensive equipment as laparoscopic repair, and it is likely to have a much shorter learning curve.