The evaluation, preoperative and operative aspects of abdominal wall reconstruction for giant ventral hernia

BACKGROUND: The optimal method for surgical repair of giant ventral hernia remains to be determined. Different concepts for reinforcement have been used, which have decreased the risk for recurrence. However, the use of foreign material has shown potential adverse effects such as pain, enterocutaneus fistula and decreased comfort of the corset caused by stiffness and pain. In an attempt to explore ways to decrease surgical complications in giant ventral hernia repair, a randomized study comparing synthetic material with autologous full thickness skin transplantation was planned and executed. In order to conduct such a study and detect any differences, it was first necessary to develop instruments for the evaluation of patient related outcome measurements. This included assessment of pain which is known to be an outcome in inguinal hernia surgery. Also, the effect on abdominal strength after medialization of the rectus muscles is something that has been previously discussed but not explored in randomized studies. Similarly, the effectiveness of using a post- operative elastic girdle in connection with abdominal surgery and abdominal wall reconstruction has not been previously studied in detail. Giant ventral hernia affect the integrity of the abdominal wall. Abdominal rectus diastasis (ARD) elicit a similar affect on abdominal wall integrity. This being the case, the effectiveness of ARD repair could shed some light on the repair of giant ventral hernia.

METHODS: A questionnaire was tailored to evaluate hernia related pain and its interference with the daily activities of a patient’s life. This questionnaire was validated compared to the existing BPI questionnaire assessing general pain. For validation purposes, focus groups with patients operated for ventral hernia were utilized. Test retest reliability was assessed by distributing the VHPQ and BPI to patients who had previously undergone ventral hernia repair. In total, 225 patients were involved in this study.

To be able to evaluate the effect of surgical reconstruction of ARD where the abdominal muscles are brought together, 57 patients underwent evaluation with the VHPQ and their results were compared with abdominal wall strength measured with the Biodex pre- and postoperatively.

A randomized trial evaluating the effect of wearing an elastic abdominal girdle was conducted with 48 patients after midline laparotomy. Postoperative cough-PEF, spirometry, pain and wound healing were evaluated.

Ultimately, as planned, the randomized study of abdominal wall reconstruction in patients with giant ventral hernia was designed and initiated, including 52 patients. Randomization was performed to create parallel groups for reconstruction using synthetic mesh or autologous full-thickness skin transplant. The primary outcome was surgical complications after 3 months. Post-operative evaluation was performed by a surgical specialist not otherwise involved in the study and blinded to the reconstruction method used.

RESULTS: The VHPQ showed good validity and reliability when compared to the BPI and evaluation of test-retest stability. A relationship between preoperative ratings on VHPQ questions regarding performing sports and sitting for more than 30 minutes and the effect of surgical repair in terms of improved muscle strength was revealed for patients with ARD. The use of a post-operative elastic abdominal girdle following laparotomy did not impair respiratory function but seemed to decrease post-operative pain.

Abdominal wall reconstruction using full-thickness skin grafts instead of synthetic mesh for abdominal wall reinforcement showed a similar complication profile at 3 month follow-up. Patients reconstructed with full-thickness skin grafts experienced less post- operative pain at 3-month follow-up.

DISCUSSION: This thesis evaluated the effect of autologous full thickness skin grafts as onlay reinforcement in the surgical repair of giant ventral hernia. Our hypothesis that the use of skin grafts would give less surgical complications was not confirmed but patients with full thickness skin grafts suffered less abdominal wall discomfort compared to those reconstructed using synthetic mesh. In the future, these patients will also be evaluated for recurrence, abdominal muscle force and adverse events at 12 and 36 months after surgery. As a precursor to embarking upon a study to evaluate abdominal wall reconstruction, a useful tool for evaluation of pain in the abdominal wall after ventral hernia surgery was generated. This instrument makes it possible to compare different surgical techniques with regard to patient experience. It may also provide a possible tool for the selection of patients with ARD who might benefit most from surgical repair. The use of an individually fitted girdle does not hinder respiratory function or wound healing. Nor does it provide a supportive effect for cough-PEF. One positive effect from wearing a girdle postoperatively is that it seems to reduce postoperative pain.

List of scientific papers

I. Clay L, Fränneby U, Sandblom G, Gunnarsson U, Strigård K. Validation of a questionnaire for the assessment of pain following ventral hernia repair - the VHPQ. Langenbeck's archives of surgery 2012;397(8): 1219-1224.
https://doi.org/10.1007/s00423-012-0932-x

II. Strigård K, Clay L, Stark B, Gunnarsson, U. Predictive factors in the outcome of surgical repair of abdominal rectus diastasis. Plastic and Reconstructive Surgery Global Open: May 2016 Volume 4 Issue 5 p e702.
https://doi.org/10.1097/GOX.0000000000000688

III. Clay L, Gunnarsson U, Franklin KA, Strigård K. Effect of an elastic girdle on lung function, intra-abdominal pressure, and pain after midline laparotomy : a randomized controlled trial. Int J Colorectal Dis. 2014;29:715-721.
https://doi.org/10.1007/s00384-014-1834-x

IV. Clay L, Stark B, Gunnarsson U, Strigård K. Full-thickness skin graft vs synthetic mesh in the repair of giant incisional hernia : a randomized controlled multicenter study. [Submitted]