You do nothing, as there is no -pathology here that needs fixing. Anything you do will be of no benefit, and subjects patient to needless risk. Now the picture found following significant trauma was perfectly consistent with diaphragmatic rupture, and I do agree that laparotomy was indicated--there was no other test to further confirm or exclude than laparotomy--in fact, as this case well demonstrates, too many tests were done as is--the contrast study is useless in this setting.
What is the most accurate diagnostic test for diaphragmatic rupture? The plain CXR--virtually 100% of cases have an abnormal CXR, tho admittedly most of these abnormalities are nonspecific--i.e. blurred or obscured diaphragm, hemothorax, rib fractures, etc. This case had a classic virtually pathognomonic finding that warranted laparotomy. I was involved in just such a case that ended up being an eventration found at lap, and the patient tried to sue--the case never got to the deposition stage before the mountain of supportive expert testimony caused the patient to withdraw the claim.