Comparison of the parasacral and winnie approaches to the sciatic nerve block combined with the psoas compartment block in knee arthroscopy

We aimed to compare the clinical effectiveness of the parasacral and the Winnie approaches to the sciatic nerve block which were combined with the psoas compartment block (PCB) in patients undergoing elective knee arthroscopies.Our research was carried out on 50 patients undergoing unilateral knee arthroscopy who were aged between 18-85 years and belong to ASA I-II risk group and who agreed to take part in the study. Fifty patients were randomized into two groups and in Group 1, patients were applied Winnie aprroach to the sciatic nerve combined with the PCB and; in Group 2, patients were applied parasacral aprroach to the sciatic nerve combined with the PCB. Each group received 20 mL of %0,375 levobupivakain and 20 mL of %1,5 lidokain for the PCB and 20 mL of %0,375 levobupivakain and 10 mL of %1,5 lidokain for the sciatic nerve blocks. We compared the time to first motor response secondary to nerve stimulation, time for the block procedures, number of attempts to elicit the nerve, number of patients in whom sensory and motor blocks developed and the time to onset of sensory and motor blocks, number of patients who received general anesthesia secondary to pain caused by tourniquet or incision and finally block success rates sufficient for the operation. We also determined relation between the body mass index (BMI) and the block procedure properties.Winnie and parasacral approaches which performed in two randomized groups with similar demographic variables were found similar for the time to first motor response secondary to nerve stimulation (Winnie vs parasacral respectively 44,9±57,4 and 51,9±57,1 sec), the time spent for the block procedures (Winnie vs parasacral respectively 161,5±61,7 and 171,5±72,8 sec) and the number of attempts to elicit the nerves (Winnie vs parasacral respectively 2,5±1,9 and 2,6±2,2). Besides no difference was observed between groups for the number of patients in whom complete sensory (Winnie vs parasacral respectively %64 ve % 68) and complete motor blocks (both groups %72) have developed. On the other hand also no difference was observed between groups for the number of patients in whom sensory (Winnie vs parasacral respectively %64 ve % 68) and motor blocks (both groups %72) in obturator nerve have developed. One additional result of our research was that while a positive correlation was found between BMI and the time to first motor response in the thigh secondary to nerve stimulation, the time spent for the block procedure and the number of attempts to elicit the nerves for PCB, no correlation was observed for both of the sciatic nerve blocks with the same determinants. Excluding the patients who have felt pain due to tourniquet or incision and had to be generally anesthetized (Winnie vs parasacral respectively %16 and %20) both groups of combinations were found similar in operative success rate (Winnie vs parasacral respectively %84 and %80). When the patients who have felt pain due to tourniquet or incision secondary to the failure in PCB were excluded, a more objective comparison of the operative success rates of the parasacral and Winnie approaches showed no difference.As a result of our study in which we have combined parasacral and Winnie approaches with the PCB; it is found that parasacral approach is not superior than Winnie approach both for the number of patients in whom sensory (Winnie vs parasacral respectively %64 ve % 68) and motor blocks (both groups %72) in obturator nerve have developed and the the remainder parameters that we have studied.