Background:
Several studies in the literature detailed specific preoperative parameters and co-morbidities that correlate with postoperative outcomes in adults. However, there is a paucity of similar data in the pediatric surgery population. The goal of this study was to elucidate which peri-operative patient characteristics are associated with an increased risk of surgical complications in children undergoing urological surgery.
Methods: We retrospectively reviewed all pediatric urological surgeries performed between April 2003-September 2006 at our institution. Patients who had an adverse or unexpected event within 30 days of surgery were identified. Over forty pre-operative patient characteristics and twenty intra-operative parameters were evaluated. The severity of the complications was graded based upon the Clavin’s Classification system. Relative risk of each parameter was calculated.
Results:
The overall complication rate was 1.3%. The complication grade and type were as followed:

Complication Type	N	%
Cardiac	1	0.9
Respiratory	0	0.0
Renal	1	0.9
Bleeding	21	18.9
Infection - Wound	9	8.1
Infection - Urine	17	15.3
Infection - Other	2	1.8
Neurologic	2	1.8
Technique	53	47.7
Other	5	4.5

Complication Grade	N	%
Grade 1	25	23.4
Grade 2	23	21.5
Grade 3A	2	1.9
Grade 3B	51	47.7
Grade 4A	3	2.8
Grade 4B	1	0.9
Grade 5	0	0.0

Some of the risk factors for complications include pre-operative weight, NPO duration, duration of surgery, surgery during July-September, and EBL/Kg . Not significant factors include sex, age at time of surgery, gestational age, birth weight, co-morbid medical conditions, ASA score, and the use of regional anesthesia
Conclusions: We observed that some of the parameters that were traditionally thought to be risk factors for surgical complications such as gestational age and co-morbid medical conditions were not significant predictors of post-operative complications, while others such as NPO duration and surgery during the July-September period were significant risk factors. Our findings will help to stratify risk and anticipate postoperative outcomes, which should be of benefit to patients, their family, the surgeons, the hospitals and insurance payers.