|Year : 2018 | Volume
| Issue : 3 | Page : 99-108
Patient-reported outcome measures 2 years after treatment of small ventral hernias using a monofilament polypropylene patch covered with an absorbable hydrogel barrier on its visceral side
Jean-Francois Gillion1, André Dabrowski2, Florent Jurczak3, Timothée Dugue4, Alain Bonan1, Jean-Michel Chollet1
1 Department of General and Visceral Surgery, Antony Private Hospital, Antony, France
2 Department of General and Visceral Surgery, Private Clinic of St Omer, St Omer, France
3 Department of General and Visceral Surgery, Public Clinic of St Nazaire, St Nazaire, France
4 Department of General and Visceral Surgery, Clinique St Pierre of Perpignan, Perpignan, France
|Date of Submission||29-Aug-2018|
|Date of Acceptance||03-Sep-2018|
|Date of Web Publication||19-Nov-2018|
Dr. Jean-Francois Gillion
Private Hospital of Antony, Antony
Source of Support: None, Conflict of Interest: None
BACKGROUND: In spite of their wide use, clinical studies on intraperitoneal ventral patches are rare, especially for VentralexTM ST (VST), recently released.
MATERIALS AND METHODS: Two-year results of 108 patients operated on from a ventral hernia with VST were assessed using a patient-reported outcome measures concept.
RESULTS: One hundred and eight patients (59.9 ± 14.65 years; body mass index 29.72 ± 8.14; wound healing risk factor in 49 patients) were prospectively registered. Surgery was clean in 105 (97%) or clean contaminated in 3 (3%). The defect was <4 cm in diameter in 81% of primaries and <4 cm in width in 91% of incisional ventral hernias. No postoperative complication occurred except one benign subcutaneous seroma. At 2 years, 15 patients could not be reached by the independent clinical research assistant, despite five attempts at different moments, while 93 (86%) completed the phone questionnaire. None declined to answer. Only one reoperation was mentioned. Three recurrences (two not reoperated) were identified. No bowel obstruction, wound sinus, or mesh migration was identified. Only three patients had pain, mild and less bothering than their treated hernia. Compared with the preoperative quality of life, evaluated with the same questionnaire, the improvement in these 93 patients was highly statistically significant (P < 0.001).
CONCLUSION: Despite potential underestimation of recurrences and rare long-term complications, this study, the first one on this new patch, suggests that VST could be safe and effective in the treatment of small primary or incisional ventral hernias. However, further studies are needed to confirm these preliminary results.
Keywords: Abdominal wall repair, incisional ventral hernia, late outcomes, mesh, patient-reported outcomes measures, primary ventral hernia, prosthesis
|How to cite this article:|
Gillion JF, Dabrowski A, Jurczak F, Dugue T, Bonan A, Chollet JM. Patient-reported outcome measures 2 years after treatment of small ventral hernias using a monofilament polypropylene patch covered with an absorbable hydrogel barrier on its visceral side. Int J Abdom Wall Hernia Surg 2018;1:99-108
|How to cite this URL:|
Gillion JF, Dabrowski A, Jurczak F, Dugue T, Bonan A, Chollet JM. Patient-reported outcome measures 2 years after treatment of small ventral hernias using a monofilament polypropylene patch covered with an absorbable hydrogel barrier on its visceral side. Int J Abdom Wall Hernia Surg [serial online] 2018 [cited 2022 Aug 17];1:99-108. Available from: http://www.herniasurgeryjournal.org/text.asp?2018/1/3/99/245595
| Introduction|| |
Even for small abdominal hernias, mesh repair reduces the recurrence rate but could entail serious adverse events. Intraperitoneal patches implanted through a small direct route have been widely used despite sparse clinical evaluation.,, Partially due to the large number of implantations, some rare complications occurred, potentially related to the shrinkage of the patch.,
The aim of this study was to assess the 2-year follow-up results of the Ventralex™ ST (VST) in which the ePTFE layer has been replaced with an absorbable hydrogel.
| Materials and Methods|| |
Ventralex™ ST (Davol Inc., Subsidiary of C. R. Bard Inc., Warwick, Rhode Island, USA) is a monofilament polypropylene patch completed with an absorbable hydrogel (hyaluronic acid/carboxymethyl cellulose: Seprafilm™) on its visceral side.
We carried out a retrospective analysis of data prospectively registered in our large multicenter cooperative registry. In this registry, a systematic control by phone call of all patients is scheduled at 2 and 5 years postoperatively. The data of all patients operated on from a ventral hernia with implantation of a VST patch between January 1, 2012 and December 31, 2014 were extracted and analyzed.
As suggested by Kockerling et al. and others,, the results of primary ventral hernia repairs (PVHR) and incisional ventral hernia repairs (IVHR) were studied separately and compared before being pooled.
The Strengthening the Reporting of Observational studies in Epidemiology recommendations for the reporting of observational studies as well as the European Registry of Abdominal Wall Hernias recommendations were used for this study.,
Our registry is a collaborative, prospective, encrypted (random identifying number) online database of all hernia surgery procedures performed by nearly 50 French surgeons with a specific interest in abdominal wall surgery. Each participating surgeon must accept and sign a Charter of Quality, which states that: “all input must be registered in a consecutive, unselected, and exhaustive manner and in real time” (NB: before the outcomes are known). The registry complies with the rules of the French “Commission Nationale de l'Informatique et des Libertés” (CNIL; registration number 1993959v0).
Data collection and extraction
A total of 164 parameters were retrieved from the registry, including screening, pre-, peri-, and postoperative outcomes. Patients were examined by their operating surgeon at discharge, and at least 1 month after the surgery. One optional additional clinical visit at the 3rd month was scheduled if the patient was not asymptomatic at the 1st-month control. All postoperative complications were classified according to the Clavien–Dindo classification. Pain was assessed at Day 0 (D0), Day 1 (D1), and Day 8 (D8) after surgery using a 0-10 visual analog score (VAS).
Follow-up and primary end-point: patient-reported outcomes measures
A telephone follow-up was carried out after 2 years of each surgery by an independent clinical research associate blinded to the surgical procedure. Patients were declared lost to follow-up only after five attempts, at different moments, at different days, using different phone numbers if available.
Quality of life was self-assessed by the patient through a validated questionnaire used in our studies since 1999., According to a patient-reported outcome measures (PROM) concept, the patient's answers were registered without any medical adjustment. The same questionnaire was used before surgery and at each step of the follow-up allowing for accurate comparisons. In case of any symptom, a clinical visit with the operating surgeon was strongly suggested. If any discrepancy was to be noticed between the database and the patient's recall after 2 years, the medical chart was to be consulted together with the operating surgeon.
Means and standard deviations were obtained for all continuous variables and valid percentages were calculated for all categorical variables. In case of missing data, percentages were calculated using available data. Comparisons of PVHR and IVHR results were performed using the Chi-square test for qualitative variables and the Student's t-test for quantitative data. P < 0.05 was considered statistically significant.
| Results|| |
PRISMA flow chart
Our database offers information on 7472 ventral hernia repairs registered between October 1, 2011 and July 27, 2017. A total of 756 repairs correspond to Ventralex™ patches of any type, of which 304 were VST patches. Of these, 192 were excluded from the analysis because the surgeries took place after January 1, 2015 and 4 were excluded because of missing contact details of the patients, therefore impeding follow-up after 2 years [Figure 1]. Therefore, a total of 108 patients implanted with VST were included in this analysis: 63 corresponded to PVHR and 45 were IVHR, with the first record dating back to January 2012.
Global patients' characteristics are described in [Table 1]. There were no statistically significant differences between the IVHR and the PVHR subgroups regarding age, body mass index, male proportion, percentage of patients evaluated as American Society of Anesthesiologists III-IV, and wound healing risk factors. However, global risks factors were more frequent in IVHR, mainly related to their herniation risk factor (personal and familial hernia history).
Hernia and surgical characteristics
Location wise [Table 2], the treated hernias were mainly median (94%) and 81% were symptomatic. VST was rarely (4%) inserted in an emergency setting, skin alterations were present in 18% of the cases, and no wound was contaminated or dirty. Overall, 62% of IVHR patients received a prophylactic antibiotic therapy versus 24% of PVHR patients (P < 0.001).
The defect was <4 cm in diameter in 81% of primaries [Table 3] and <4 cm in width in 91% of incisional ventral hernias. Patches of 4.3 cm, 6.4 cm, and 8 cm in diameter were inserted in 36%, 34%, and 30% of the cases, respectively. The defect was closed in all cases. Patches of 8 cm in diameter were significantly less used in IVHR patients. VST were inserted intraperitoneally in 94% of cases. The most common patch fixation method was sutures (94% of cases). Staples were only used with 8 cm in diameter patches. There were no peroperative complications and the mean operative time was 25 min in both subgroups.
Postoperative outcomes at 30 days
Overall [Table 4], 52% of patients were treated in a 1-day surgery setting, with significant differences between PVHR (63%) and IVHR (36%) subgroups. The mean length of stay for inpatients was 1.8 ± 1 days. No readmissions and no reoperations were registered. Only one complication occurred during the 1st month: a subcutaneous seroma spontaneously resolving within the 1st month (Clavien–Dindo Grade I). The postoperative outcomes were double checked during the 2-year phone call. No forgotten complication was found. The mean VAS at D0, D1, and D8 were 2.9 ± 1.8, 2.7 ± 1.6, and 0.9 ± 1.3, respectively. The VAS was significantly lower in the IVHR subgroup at D1.
First-month and third-month clinical controls
Ninety-four patients had a 1st-month clinical control with their operating surgeon [Table 5]. None had a VAS score higher than 2 and 84% had a VAS score of 0. Only one patient assessed his discomfort as more troublesome than his treated hernia. His discomfort disappeared within the first 2 months and he assessed the procedure as excellent or good in the 2-year follow-up interview. The mean sick leave for workers was 19.4 ± 12.5 days, ranging from 16.9 in PVHR to 22.8 in IVHR (P = 0.002) [Table 5].
Five patients (3 PVHR and 2 IVHR) were reviewed at 3 months after surgery. Only one reported having a persisting discomfort, which was, however, less bothersome than his treated hernia (these results not shown in Tables). All five patients assessed their procedure as “excellent or good” after 2 years.
Two-year follow-up outcomes and quality of life
Fifteen patients were lost to follow-up, with no statistical differences in lost-to-follow-up rates between subgroups [Table 6]. No death was mentioned and all contacted patients agreed to answer the telephone questionnaire. The mean age of patients lost to follow-up, 70.5 ± 12.5 years, was significantly (P = 0.002) higher than the mean age of the patients followed (58.2 ± 14.3 years). Two recurrences (2%) were identified [Table 6]. One had laparoscopic repair 6 months after the index VST repair, and the patient assessed his 2-year result as “excellent or good.” The second asymptomatic was reluctant to a redo surgery. One patient assessed his abdominal wound as not solid but was reluctant to undergo a clinical control. All other patients assessed their abdominal wound as solid. No obstruction or visceral erosion were reported by the patients after 2 years. Three patients mentioned experiencing mild pain or discomfort, but none had to take analgesics. All three assessed their discomfort as less troublesome than their treated hernia. Overall, 97% of the patients assessed the result of their surgery as excellent or good [Table 7]. Compared with the preoperative one, the 2-year quality-of-life evaluated with the same questionnaire, dramatically improved [Table 7]. The difference was statistically highly statistically significant (P < 0.001).
|Table 7: Patient reported outcomes (patient reported outcomes measures) at 2-year follow-up compared with baseline (preoperative period)|
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| Discussion|| |
This is the first study on medium-term results of patients treated for ventral hernias with Ventralex™ ST (VST). The patients assessed the result of their surgery according to a PROM methodology without any medical adjustment. Compared with their preoperative status evaluated with the same questionnaire (baseline), the improvement of their quality of life at 2-year follow-up [Table 7] was highly statistically significant (P < 0.001). Moreover, patients reported a very low rate of complications: two recurrences and no late complications such as bowel obstruction, wound sinus, mesh migration, or chronic pain. After 2 years, only 3 in the 93 followed patients (3%) answered they occasionally suffer of pain, mild and less troublesome than the treated hernia.
Two recurrences (2%) were identified [Table 6]. One had laparoscopic repair 6 months after the index VST repair, and the patient assessed his 2-year result as “excellent or good.” The second asymptomatic was reluctant to a redo surgery. One patient assessed his abdominal wound as not solid but was reluctant to undergo a clinical control. All other patients assessed their abdominal wound as solid.
This 2%–3% recurrence rate is comparable with those already published after repairs using Ventralex™ PTFE (VPTFE), which range from 8.3% to 11.7%,,, Proceed™ Ventral Patch (PVP) or PCO™ ventral patch (PCOVP), both around 3%. One study using CABS'AIR™ reported a recurrence rate of 0%.
As in those above studies, the defects we treated were mainly small. The defect was less than 4 cm in diameter in 81% of primaries, and <4 cm in width in 91% of incisional ventral hernias. Patches of 4.3 cm, 6.4 cm, and 8 cm in diameter were inserted in 36%, 34%, 30% of the cases, respectively. When using a bridging technique, a ratio of mesh area to defect area ≥13 is recommended. The defect was closed in all our cases without bridging. Our recurrence rate may be potentially underestimated because our patients did not undergo a systematic clinical examination after 2 years. Patients mentioned only one reoperation for recurrence and no additional reoperation for other reason [Table 7]. Of course, the reoperation rate per se may underestimate the recurrence rate by four-to-fivefolds, but compared to their preoperative condition, 91 of our 93 followed patients assessed their abdominal wound as solid [Table 7].
Due to the lack of this specific entry in our registry, we could not estimate the number of trocar-site IVHR treated with VST. Largest VST were rare in the IVHR group, probably because in not-small IVHR, the surgeon opted for other surgical techniques and did not implant a VST.
No obstruction and no visceral complications were reported at the 2-year follow-up interview. Intraperitoneal prostheses are at risk of obstruction due to adhesions to the mesh or to the staples required to fix the prosthesis in laparoscopic repairs. Intraperitoneal staples are not required to fix Ventralex™ patches. Conversely, the correct deployment of a mesh, which is easy to check during laparoscopy, is difficult to ensure and to verify through a small open approach, as pointed out in a systematic laparoscopic evaluation of both VPTFE and PCOVP. The balloon of CABS'AIR might help. VST has a pocket, helping to ensure and verify the correct deployment of the patch. However, two additional precautions must be taken: (1) before inserting the patch, the surgeon must have perfectly flatten out the inner part of the abdominal wound removing the fat of the round ligament and (2) after inserting the patch, the surgeon must avoid an excessive traction on the straps in order to avoid a cone shape deformation of the patch.
Visceral erosions by the intraperitoneal patch and migrations of the patch are rare but serious complications., In the three cases reported by Muysoms et al., two concerned 8-cm VPTFE and one related to PVP. In the first case (VPTFE), a potato chip phenomenon was observed, in the two others (VPTFE and PVP) the shrinkage of the mesh seemed to be the cause. In the randomized study of Bensaadi et al., six patches had to be explanted for chronic pain attributed to shrinkage of the VPTFE.
Only case reports have been published. More than 10 years ago, we personally had to perform a bowel resection with “en bloc” patch removal to treat a patch migration. None since this case, what underlines the frequent long delay between surgery and complication. Even potentially underreported, the incidence of these serious complications seems very rare, with regard to the large number of implanted patches worldwide. Large registries could help detect such rare complications. That said, in our database, among 30,000 patients registered since 2011, including 7472 ventral hernia repairs, including 756 VPTFE or VST [Figure 1], we did not observe such complications.
Technical-, and mesh-related issues were the most common causes of complications, such as the incomplete deployment of the mesh and the “potato chip-like” shrinkage of the mesh, especially with ePTFE layer,, leading some authors to suggest to replace the ePTFE layer with an absorbable layer.,
VST (Davol Inc., Subsidiary of C. R. Bard Inc., Warwick, Rhode Island, USA) is a monofilament polypropylene patch completed with an absorbable hydrogel (hyaluronic acid/carboxymethyl cellulose: Seprafilm™) on its visceral side. This hydrogel barrier aims to minimize tissue attachment to the visceral side of the mesh and resorbs within 30 days providing visceral protection during the critical healing process. The effectiveness of Seprafilm™ in preventing the formation of adhesions has been widely studied both in experimental and clinical studies gathered in a Cochrane review.
As an intraperitoneal mesh is at risk of specific complications, even when meshes have a dual layer, some of our members have started to explore a preperitoneal insertion of the VST. Six percentage of our VST have been implanted preperitoneally [Table 3], not in the retromuscular space but between the peritoneum and the deep aspect of the rectus sheet. Even though easier in fatty patients, this technique is achievable in almost any case. In case of peritoneal tears, the anti-adhesive barrier is protective. In case of no tears, this anti-adhesive barrier is not an issue because it is absorbable in 1 month. The main advantage is that the outer edge of the patch is covered with the peritoneum, thus preventing a bowel incarceration.
Apart from these rare complications, these small patches have many advantages which explain their wide use: these small patches allow to treat small hernias with a unique small incision; the procedure is quick and well suited for 1-day surgery; their implantation does not require wide parietal dissections entailing risks of pain, seromas, or hematomas, especially in case of patients undergoing anticoagulant therapy; their fixation does not require a single or double crown of staples nor a transfascial suture potentially painful or even further complicated with “suture hernias.”
This study is not without limitations indeed. First, both our sample size and the time to follow-up are not large enough to be sure not to miss all the rare and long-term complications. It is why our registry has been designed to follow our patients for >5 years. PROM may obviously underestimate some totally asymptomatic complications such as small and stable recurrent defects for which a watchful waiting could be considered. Some of them will have further clinical impact, but some others not. In a large registry such as ours, it would be difficult and costly for the health-care system to organize systematic clinical examinations for all patients at 1-, 2-, and 5-year postoperatively and even more. It is why we opted for a PROM follow-up.
| Conclusion|| |
This study suggests that the new VST patch could be safe and effective in the treatment of small ventral hernias. However, further studies are needed to confirm these fair results at 2-year follow-up.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Kaufmann R, Halm JA, Eker HH, Klitsie PJ, Nieuwenhuizen J, van Geldere D, et al.
Mesh versus suture repair of umbilical hernia in adults: A randomised, double-blind, controlled, multicentre trial. Lancet 2018;391:860-9.
Kokotovic D, Bisgaard T, Helgstrand F. Long-term recurrence and complications associated with elective incisional hernia repair. JAMA 2016;316:1575-82.
Martin DF, Williams RF, Mulrooney T, Voeller GR. Ventralex mesh in umbilical/epigastric hernia repairs: Clinical outcomes and complications. Hernia 2008;12:379-83.
Berrevoet E, de Hemptinne B. Open intraperitoneal mesh repair for umbilical hernias. A technical note. Acta Chir Belg 2009;109:555-8.
Bensaadi H, Paolino L, Valenti A, Polliand C, Barrat C, Champault G, et al.
Intraperitoneal tension-free repair of a small midline ventral abdominal wall hernia: Randomized study with a mean follow-up of 3 years. Am Surg 2014;80:57-65.
Muysoms FE, Bontinck J, Pletinckx P. Complications of mesh devices for intraperitoneal umbilical hernia repair: A word of caution. Hernia 2011;15:463-8.
Tsapralis D, Vasiliades G, Zaxou Z, Delimpaltadaki M, Margetousakis TH, Papadakis H, et al.
Bowel obstruction secondary to migration of a ventralex mesh: Report of a rare complication. Hernia 2018;22:711-4.
Berrevoet F, Van den Bossche B, de Baerdemaeker L, de Hemptinne B. Laparoscopic evaluation shows deficiencies in memory ring deployment during small ventral hernia repair. World J Surg 2010;34:1710-5.
Berrevoet F, Doerhoff C, Muysoms F, Hopson S, Muzi MG, Nienhuijs S, et al.
A multicenter prospective study of patients undergoing open ventral hernia repair with intraperitoneal positioning using the monofilament polyester composite ventral patch: Interim results of the PANACEA study. Med Devices (Auckl) 2017;10:81-8.
Köckerling F, Schug-Paß C, Adolf D, Reinpold W, Stechemesser B. Is pooled data analysis of ventral and incisional hernia repair acceptable? Front Surg 2015;2:15.
Stirler VM, Schoenmaeckers EJ, de Haas RJ, Raymakers JT, Rakic S. Laparoscopic repair of primary and incisional ventral hernias: The differences must be acknowledged: A prospective cohort analysis of 1,088 consecutive patients. Surg Endosc 2014;28:891-5.
Kroese LF, Gillion JF, Jeekel J, Kleinrensink GJ, Lange JF, Hernia-Club Members, et al.
Primary and incisional ventral hernias are different in terms of patient characteristics and postoperative complications-A prospective cohort study of 4,565 patients. Int J Surg 2018;51:114-9.
Vandenbroucke JP, von Elm E, Altman DG, Gøtzsche PC, Mulrow CD, Pocock SJ, et al.
Strengthening the reporting of observational studies in epidemiology (STROBE): Explanation and elaboration. Ann Intern Med 2007;147:W163-94.
Muysoms FE, Deerenberg EB, Peeters E, Agresta F, Berrevoet F, Campanelli G, et al.
Recommendations for reporting outcome results in abdominal wall repair: Results of a consensus meeting in Palermo, Italy, 28-30 june 2012. Hernia 2013;17:423-33.
Kyle-Leinhase I, Köckerling F, Jørgensen LN, Montgomery A, Gillion JF, Rodriguez JA, et al.
Comparison of hernia registries: The CORE project. Hernia 2018;22:561-75.
Dindo D, Demartines N, Clavien PA. Classification of surgical complications: A new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg 2004;240:205-13.
Gillion JF, Fromont G, Lepère M, Letoux N, Dabrowski A, Zaranis C, et al.
Laparoscopic ventral hernia repair using a novel intraperitoneal lightweight mesh coated with hyaluronic acid: 1-year follow-up from a case-control study using the hernia-club registry. Hernia 2016;20:711-22.
Kroese LF, Kleinrensink GJ, Lange JF, Gillion JF, Hernia-Club. External validation of the European hernia society classification for postoperative complications after incisional hernia repair: A cohort study of 2, 191 patients. J Am Coll Surg 2018;226:223-90.
Weldring T, Smith SM. Patient-reported outcomes (PROs) and patient-reported outcome measures (PROMs). Health Serv Insights 2013;6:61-8.
Muysoms FE, Miserez M, Berrevoet F, Campanelli G, Champault GG, Chelala E, et al.
Classification of primary and incisional abdominal wall hernias. Hernia 2009;13:407-14.
Tollens T, Den Hondt M, Devroe K, Terry C, Speybroeck S, Aelvoet C, et al.
Retrospective analysis of umbilical, epigastric, and small incisional hernia repair using the ventralex™ hernia patch. Hernia 2011;15:531-40.
Berrevoet F, D'Hont F, Rogiers X, Troisi R, de Hemptinne B. Open intraperitoneal versus retromuscular mesh repair for umbilical hernias less than 3 cm diameter. Am J Surg 2011;201:85-90.
Tollens T, Mitchell J, Jones P, Berrevoet F. A prospective study of one-year clinical outcomes utilizing a composite three-dimensional device with a tissue-separating layer for repair of primary ventral and small incisional hernia. Surg Technol Int 2014;24:195-202.
Hauters P, Desmet J, Gherardi D, Dewaele S, Poilvache H, Malvaux P, et al.
Assessment of predictive factors for recurrence in laparoscopic ventral hernia repair using a bridging technique. Surg Endosc 2017;31:3656-63.
Helgstrand F, Rosenberg J, Kehlet H, Strandfelt P, Bisgaard T. Reoperation versus clinical recurrence rate after ventral hernia repair. Ann Surg 2012;256:955-8.
García-Moreno F, Pérez-López P, Sotomayor S, Pérez-Köhler B, Bayon Y, Pascual G, et al.
Comparing the host tissue response and peritoneal behavior of composite meshes used for ventral hernia repair. J Surg Res 2015;193:470-82.
Kumar S, Wong PF, Leaper DJ. Intra-peritoneal prophylactic agents for preventing adhesions and adhesive intestinal obstruction after non-gynaecological abdominal surgery. Cochrane Database Syst Rev 2009;1:CD005080. doi: 10.1002/14651858.CD005080.pub2. Review.
Morales-Conde S, Cadet H, Cano A, Bustos M, Martín J, Morales-Mendez S, et al.
Laparoscopic ventral hernia repair without sutures–Double crown technique: Our experience after 140 cases with a mean follow-up of 40 months. Int Surg 2005;90:S56-62.
Muysoms FE, Cathenis KK, Claeys DA. “Suture hernia”: Identification of a new type of hernia presenting as a recurrence after laparoscopic ventral hernia repair. Hernia 2007;11:199-201.
Verhelst J, Timmermans L, van de Velde M, Jairam A, Vakalopoulos KA, Jeekel J, et al.
Watchful waiting in incisional hernia: Is it safe? Surgery 2015;157:297-303.
Kokotovic D, Sjølander H, Gögenur I, Helgstrand F. Watchful waiting as a treatment strategy for patients with a ventral hernia appears to be safe. Hernia 2016;20:281-7.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]