From the Journals

COBRA trial takes the long view of absorbable biosynthetic mesh outcomes

 

Key clinical point: Biosynthetic surgical mesh had durability and costs comparable with those for biologic mesh for hernia repair.

Major finding: At 24 months, 17% of patients were found to have a hernia recurrence.

Data source: An international, multisite, prospective, intention-to-treat cohort analysis of 104 patients with contaminated or noncontaminated hernia defects of at least 9 cm2 in size.

Disclosures: The study was funded by W.L. Gore. The authors had no relevant financial disclosures.


 

Absorbable, biosynthetic surgical mesh used to repair ventral hernia defects may be a good alternative to biologic and permanent synthetic mesh products both in terms of long-term durability and cost, according to a longitudinal cohort study.

The results of the COBRA (Complex Open Bioabsorbable Reconstruction of the Abdominal Wall) study published in the January issue of Annals of Surgery represent the longest follow-up of patients in whom this product was used. Lead author of the study, Michael J. Rosen, MD, professor of surgery at Case Western Reserve University, Cleveland, and his colleagues wrote: “Absorbable synthetic mesh has the prospective advantages of a reduced cost, minimal constraints in manufacturing alternative sizes (lengths, widths, and thicknesses), informed consent in certain religious or cultural groups, and ability to be iterative in generational improvements in mesh constructs based on outcome studies, compared with allogeneic or xenogenic mesh.”

Surgery being performed ©Dmitrii Kotin/Thinkstock.com
The study adds to the growing literature assessing long-term outcomes and durability of mesh for hernia repair in a contaminated and clean-contaminated operative field. The international, multisite prospective intention-to-treat analysis of 104 patients – primarily obese women in their late 50s – with a hernia defect of at least 9 cm2, investigated surgical repair using a fascial closure and Gore Bio_A Tissue Reinforcement, a mesh made of a bioabsorbable polyglycolide-trimethylene carbonate copolymer. The matrix structure of the biosynthetic material allows it to be absorbed into the body within 6 to 7 months via hydrolysis, and facilitates tissue growth and healing at the wound site.

Contaminated wounds were present in 77% of participants. About one-fourth of patients had concomitant procedures for fistula takedown; a quarter of the cohort also required the removal of infected, previously placed mesh. More than a fifth of patients required a concomitant repair of both a midline and parastomal hernia; the mean size for the hernia defects was 137 cm2, and the average width was 9 cm.

Placement of the biosynthetic mesh was left to the discretion of the surgeon, but 90% chose retrorectus placement. Primary fascial closure using a single unit of the material was successful in all patients, 68 of whom required concomitant component separation; 21 of these had an external oblique release. Another 50 of these had transversus abdominis release.

At 24 months, when 84% of patients completed follow-up, 17% were found to have a hernia recurrence. Intraperitoneal placement of the material was found to significantly increase the risk of hernia recurrence (P less than or equal to .04). Infections at the surgical site were associated with a higher risk of recurrence (P less than .01). Patient-reported physical and mental quality-of-life scores at 24 months improved significantly from baseline (P less than .05), showing sustained improvement at 6 and 12 months post procedure.

While more studies are needed, the COBRA findings suggest absorbable, biosynthetic mesh compares favorably with biologic mesh when it comes to recurrence. “The Repair of Infected and Contaminated Hernias (RICH) trial is the only long-term, multicentered, prospective trial to evaluate biologic mesh in CDC [Centers for Disease Control and Prevention] class II to IV wounds. The RICH trial reported 66% surgical site occurrence and 28% hernia recurrence after 2 years’ follow-up in patients who underwent ventral hernia repair with a non–cross-linked porcine dermis,” the investigators noted.

Cost is another area in which bioabsorbable synthetic mesh compares favorably with the biologics, not only in terms of savings from fewer recurrences but also the cost of the mesh itself. Biologic mesh can cost $10,000 or more while synthetics run about a quarter of that (Clin Colon Rectal Surg. 2014 Dec; 27[4]:140-8).

In conclusion, the investigators commented that despite the lack of a control group and random assignment in the study, the results “should not be underestimated” when considering alternatives to biologic and costlier, permanent synthetic meshes.

The study was funded by W.L. Gore. The authors had no relevant financial disclosures.

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