Since the 1920’s, immediate postoperative pulmonary compromise has been a feared complication after repair of massive abdominal hernias. The concept of a “lost abdominal domain” was introduced in the 1950’s as a possible, yet untested reason for pulmonary complications, as well as for hernia recurrence. The loss of domain concept states that in patients with massive abdominal hernias where there has been a longstanding existence of bowel outside the abdominal wall musculature, the viscera lose their right to reside in the abdominal compartment secondary to loss of abdominal muscle elasticity and diaphragmatic descent. This is turn leads to a decreased peritoneal volume. As such, we postulate that increasing the volume of the abdominal compartment during hernia repair will help to reverse the sequelae of a lost domain—namely, pulmary complications. We present our hernia repair experience using the separation of parts hernia technique, with particular attention to the issue of postoperative ventilation.
A consecutive series of 107 patients treated by a single surgeon using the separation of parts technique was reviewed retrospectively. All patients underwent bilateral release of the external oblique muscles from above the rib cage to the iliac crest (but no other releases). 7 patients included in this study also had tensor fascia lata grafts. No prosthetic mesh was used in any of the patients of this study.
8 patients in this series with massive hernias had relevant preoperative and postoperative CT scans of the abdomen and pelvis. These scans were imported into Pinnacle 3 software (Philips ADAC). The volume of the abdominal compartment was defined by outlining the contour of the peritoneum in each slice of the CT study. The software was used to interpolate the contours and create an accurate total volume of the patient’s abdominal compartment. Paired statistics were used to compare volume before and after hernia repair.
No patient in this series was turned away for fear of postoperative respiratory compromise. Despite several patients having rectus muscles separated from each other by 20 cm by CT scan, only 9 patients had compromise of postoperative ventilation. Five patients remained intubated overnight, 2 patients required supplemental oxygen for over one week, and the last two patients required several weeks of ventilation. These last two hernia patients each had required bowel resections, and each had a healed tracheostomy scar from a previous episode of ventilatory failure. Of the 9 patients with compromised postoperative ventilation, 6 had documented preexisting pulmonary disease.
Volumetric analysis of the abdomen in 8 patients demonstrated a mean preoperative volume of 8020 +/- 1900 cm3, and an increase in mean postoperative volume to 9000 +/- 2290 cm3 (p=.003).
We believe that the lower than expected rate of post-operative ventilatory problems in patients with “lost domains” after separation of parts hernia repairs is due to an expansion of the intraabdominal capacity. The diaphragm no longer has to rise so much during the return of the viscera into the abdomen. The computer technique of abdominal volume analysis may be helpful in the comparison of various types of abdominal wall reconstruction. We maintain that the separation of parts hernia repair helps to reestablish the lost abdominal domain.