DASH and Incisional Hernias

US Good Alternative to CT for Characterizing Incisional Hernias: Study
By James E. Barone MD
June 03, 2014

NEW YORK (Reuters Health) - Using dynamic abdominal sonography to measure incisional hernias is equivalent to using computerized tomography (CT), according to a new study.

As opposed to a CT scan, dynamic abdominal sonography for hernia (DASH) is a bedside procedure, its results are available immediately and it does not use ionizing radiation, researchers write in JAMA Surgery, online May 28.

"The DASH examination is a feasible and accurate method for evaluating hernias, particularly in those patients who have smaller hernias and who may have unclear physical exam findings," lead author Dr. Rebeccah B. Baucom from Vanderbilt University Medical Center in Nashville, Tennessee, told Reuters Health by email.

A previous paper by Dr. Baucom and colleagues showed that CT was better at detecting incisional hernias than physical examination by surgeons. In another study, the team found that DASH was as accurate as CT scan in diagnosing hernias.

To see if DASH could be used to plan operative procedures using measurements of hernia defect size, the researchers compared it with CT scans in 109 patients. One surgeon performed all of the DASH examinations, whereas one of three surgeons read the CT scans.

The mean patient BMI was 32.2, and 34% of the patients had at least one previous hernia repair.

As measured by CT, the mean surface area of hernias was 44.6 cm2, compared to 41.8 cm2 with DASH (p=0.82). The transverse dimensions were nearly identical at 5.20 cm for CT and 5.17 cm for DASH (p=0.71).

Measurements were comparably accurate for CT scan and DASH among the 14 morbidly obese patients (BMI>39.9), 49 who were obese (BMI 30 to 39.9), and 46 who had a BMI under 30.

The authors also looked at the subgroup of hernias that were 10 cm or larger in transverse dimension. Of the 15 patients in that category, the mean surface area of the hernias was 189.4 cm2 by CT and 171.3 cm2 by DASH, an insignificant difference (p=0.26).

"Several of our surgeons perform DASH examinations on their patients who present with suspected incisional hernias," said Dr. Baucom, adding that it is also being done more and more often at follow-ups after repair.

Dr. Michael Liang, who has studied ventral hernia repair but was not involved in the new work, said, "DASH is a safe and potentially effective modality for the surgeon to use to assess ventral incisional hernias."

But Dr. Liang, of the University of Texas Health Sciences Center at Houston, raised a number of concerns about the study. For example, he told Reuters Health, the authors did not use operative findings, the gold standard, to validate the ultrasound and CT results, nor did they adjust for the size of the hernias.

For recurrent, large, and complex ventral hernias, Dr. Liang said a CT scan will be obtained regardless of DASH availability because the former modality "is useful to assess defect size, peritoneal volume, lateral muscles, abdominal wall thickness and contraction, intra-abdominal organs, and old mesh."

According to Dr. Baucom and colleagues, however, DASH plus physical examination have been sufficient to evaluate most of these structures and relationships.

SOURCE: http://bit.ly/1nZk6EV

JAMA Surgery 2014.