Diaphragmotomy enhances caudal liver displacement and hilus visualization in canine cadavers

To quantify the amount of hilar liver retraction achieved with and without diaphragmotomy in canine cadavers.

6 healthy canine cadavers euthanized for reasons unrelated to the study underwent laparotomy in 2023. Fiducial radiopaque markers were placed on the hepatic coronary ligament and diaphragm. Fluoroscopic images were taken at 3 liver manipulation phases: (1) before caudal retraction (CR) (pre-CR), (2) after caudal retraction (post-CR), and (3) after diaphragmotomy (D) with caudal retraction (post-D+CR). Two measurement methods were used to evaluate hepatic caudal displacement. Method 1 used the cranial edge of the closest rib caudal to the liver as a landmark. Method 2 used a fixed point on an esophageal measurement catheter. Linear displacement for both methods at the 3 stages of liver retraction was estimated by linear repeated-measures mixed models. Limits of agreement were estimated by 95% CIs.

Linear caudal displacement was substantially increased post-CR and post-D+CR compared to pre-CR. Compared with pre-CR, the mean linear caudal displacement increased by 2.6 and 3.8 cm for post-CR for methods 1 and 2, respectively. Linear displacement increased by an additional 3.0 cm (method 1) and 3.1 cm (method 2) for post-D+CR. Method 2 measurements consistently exceeded method 1 measurements for both total and relative linear distance.

Diaphragmotomy coupled with manual retraction allows greater caudal retraction of the liver hilus than without diaphragmotomy.

This preliminary study shows that the diaphragmotomy procedure may enhance exposure and ease of manipulation and potentially reduce complications associated with limited maneuverability during hilar hepatic surgery.