A funnel-shaped intra-abdominal mesh placed during permanent colostomy formation was associated with lower rates of parastomal hernia at 3 years compared with no mesh among patients undergoing rectal cancer surgery, according to follow-up results from the randomized Chimney Trial.
The multicenter, radiology-blinded trial included patients in Finland and Sweden undergoing laparoscopic or robot-assisted abdominoperineal excision or low Hartmann procedure for rectal adenocarcinoma with curative intent and permanent end colostomy. The study originally evaluated 12-month computed tomography (CT)-confirmed parastomal hernia (PSH) as its primary endpoint, with longer-term outcomes assessed during ongoing follow-up.
Of 143 randomized patients, 101 were available for clinical analysis at 3 years, including 50 in the mesh group and 51 in the control group. CT imaging was available for 44 and 39 patients, respectively.
At 3 years, CT-confirmed PSH occurred in 57% of patients in the mesh group compared with 82% in the control group. Clinically diagnosed PSH occurred in 10% vs 39%, respectively. Hernias in the mesh group were also smaller, with lower median hernia volume and smaller fascial defects.
Reoperation for PSH was uncommon, occurring in 1 patient in the mesh group and 4 patients in the control group. No statistically significant differences were observed in reoperations for small bowel obstruction, stoma-related complications, or quality-of-life scores measured by the 36-Item Short Form Health Survey and Colostomy Impact Score.
The researchers said the gap between radiographically detected and clinically diagnosed PSH underscores the limitations of CT imaging alone, because many imaging-detected hernias remain asymptomatic and may never require intervention. Although CT-confirmed PSH increased over time in both groups, the investigators suggested that funnel-shaped mesh may help limit progression to clinically significant disease.
The findings add to ongoing debate over prophylactic mesh for PSH prevention. Prior randomized trials evaluating retrorectus keyhole mesh techniques have not consistently reduced PSH rates, whereas the Chimney Trial evaluated a different intraperitoneal funnel-shaped design intended to address limitations of flat keyhole mesh.
The trial was terminated early after the 12-month clinical PSH rate in the control group exceeded the prespecified threshold, reducing the planned sample size and statistical power. Additional limitations included incomplete blinding following discharge, the relatively low mean body mass index of the study population, and the use of highly specialized centers, which may limit generalizability.
In an invited commentary, Clayton Petro, MD, of Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, and Benjamin K. Poulose, MD, of The Ohio State University Wexner Medical Center, described the trial as a well-executed study addressing a difficult surgical problem while cautioning against viewing prophylactic mesh as a definitive solution.
The commentators noted that more than half of patients in the mesh group still developed CT-detected PSH by 3 years and warned that intraperitoneal mesh near bowel could complicate future repair procedures if hernias later become symptomatic. They also questioned how well the technique would translate to patients with obesity, given the study population’s relatively low mean BMI of approximately 26.5.
Despite lower PSH rates, increased hernia formation in the control group did not translate into statistically significant differences in quality-of-life scores or substantially higher reoperation rates over the follow-up period, the commentators noted. They argued that PSH should be approached as a chronic disease process requiring long-term management strategies rather than a condition likely to be solved by a single preventive operation.
“We need to completely rethink how we approach the disease process of parastomal hernia,” Dr Petro and Dr Poulose wrote.
Disclosures: The study was funded by the European Hernia Society Research Fund and the Ella & Georg Ehrnrooth Foundation. Dr Mäkäräinen reported personal fees from Medtronic and Dynamesh and grants from the European Hernia Society and the Ella & Georg Ehrnrooth Foundation during the study. Dr Rautio reported a host/proctor contract with Intuitive outside the submitted work. Dr Petro reported personal fees from Medtronic, Gore Medical, BD Interventional, and TelaBio/Advanced Medical Solutions, and grants from Merck. Dr Poulose reported grants from Advanced Medical Solutions and BD Interventional, salary support from the Abdominal Core Health Quality Collaborative, consulting fees from AbbVie/Allergan, and equity from EndoEvolve.
Source: JAMA Surgery
