Retroperitoneal pus collection: image guided percutaneous versus primary surgical drainage

ABSTRACT

Retroperitoneal infection is an uncommon entity, mostly presents as psoas abscess. This may be primary with no definite aetiology mostly caused by staphylococcus aureus, or secondary to tuberculosis of the spine or infection of adjacent retroperitoneal organs. Clinical diagnosis is difficult because of non-specific symptoms, resulting in delayed discovery and high morbidity and mortality. Modern imaging diagnostic techniques such as ultrasound and computerized tomography have allowed for a refinement in both the aetiologic diagnosis and the treatment by means of CT-guided or ultrasound-guided percutaneous drainage of the abscess, thus avoiding surgical drainage in many cases. This study included 29 cases [20 males and 9 females, ratio 2.2 1], studied Between August 1995 and August 2001. Their age ranged from 10 to 77 years [mean 43 years]. Pus collection was located on the right side in 17 cases, on the left side in 7 cases and bilateral collection was reported in 5 cases. Out of the 29 patients included in the study 15 cases [52%] had primary psoas abscess while the remaining 14 cases [48%] had retroperitoneal infection secondary to T.B. spine [5 cases], appendicitis [3 cases], pancreatitis [one case], and kidney disease [5 cases]. The main presenting symptoms were abdominal pain [86%], fever [83%] and swelling [62%]. Patients were classified into two groups group [A] included 13 cases and were subjected to primary surgical drainage under general anaesthesia, and group [B] included 16 patients who were treated by image [U/S and or CT scan] guided percutaneous drainage under local anaesthesia. Patients were followed for a period of 6 to 72 months with a mean follow up period of 36 months. Surgical drainage was successful in all cases with one postoperative mortality and no relapses on long term follow up [92% overall success]. While the localization of pus using image guidance was successful in all cases in-group B but follow up revealed recollection in 3 cases [19%] that required surgical intervention [81% overall success]. Immediately on diagnosis of retroperitoneal pus collection prompt treatment is necessary. Percutaneous drainage should be performed whenever possible and in case of failure, surgical drainage should be done. Surgical drainage has the advantage of dealing with the offending organ and can properly drain a multi-locular and rigid walled abscess. Image guided drainage can be used in critically ill patients not fit for anaesthesia and for primary unilocular thin walled abscess. It is a safe procedure with lower morbidity and mortality, shorter drainage time, better patient acceptance, easier nursing care, less hospital stay and more cost effective than open surgical drainage