Why is urological laparoscopy minimally invasive?

Objectives: Laparoscopic procedures have been developed and established with the view that a similar operative effect can be achieved with less traumatization, especially as far as systemic stress response is concerned. We report a prospective, controlled, nonrandomized animal and patient study to determine the systemic response to laparoscopic and open surgical procedures.

Methods: In the animal study, 26 female pigs underwent either a laparoscopic bilateral varix ligation followed by bilateral nephrectomy (group I), sole introduction of trocars (group II) or sole establishment of an open surgical approach (group III). In the patient study, 145 patients underwent various laparoscopic procedures (nephrectomy, renal cyst marsupialization, varix ligation), open surgical procedures (nephrectomy, inguinal orchiectomy) or extracorporeal shockwave lithotripsy (ESWL). The serum parameters interleukin (IL)-6, IL-10 and C-reactive protein (CRP) were measured before, during and after the operative procedure.

Results: In animals and patients, laparoscopy resulted in significantly lower serum levels of CRP during and after the operative procedure. Animals in group I showed a 5-fold elevation, in group II a 3-fold elevation and in group III a 9-fold elevation of CRP. In patients, the increase of CRP was twice as high after open unilateral nephrectomy than after laparoscopic unilateral or bilateral nephrectomy. IL-6 showed less marked elevation during laparoscopy, ESWL and minor operative procedures like laparoscopic varix ligation or inguinal orchiectomy when compared to an open unilateral nephrectomy. The parameter IL-10 showed no significant differences among the patient groups.

Conclusions: The extent of the acute phase reaction to the operative trauma correlates much more convincingly to the approach than to the extent of the procedure. Only larger operations like nephrectomy trigger a systemic acute phase reaction, which can be limited by the laparoscopic access. For minor operative procedures like varix ligation or exploration of cryptorchidism, laparoscopy offers technical advantages rather than minimal invasiveness.