The effect of lumbosacral plexus blocks on early postoperative cognitive functions

Postoperative cognitive dysfunction (POCD) is a fairly common situation especially in elderly patients undergoing major surgery. Whether the effectiveness of anesthesia tecniques on the development of POCD, studies conducted are focused on general anesthesia and central blocks. There have been no study found on investigating the relationship between peripheral nerve and plexus blocks with POCD in the literature search which made us aimed to research the effects of general anesthesia, spinal anesthesia and peripheral nerve and plexus blocks on the development of the early POCD with mini mental status examination (MMSE) and also the detection of blood levels of biochemical indicators of brain damage; neuron specific enolase (NSE) and S 100 ß protein.Our research was carried out on 62 unilateral total knee arthroplasty patients, between the ages of 50-85, ASA I-III risk group and who agreed to take part in the study. Applied to cases were divided into three groups according to the technique of anesthesia. General anesthesia was performed on Group I (n=21), spinal anestesia on Group II (n=21) and lumbar plexus - sciatic nerve block was performed on Group III (n= 20). MMSE had been applied and NSE and S 100 ß protein levels were measured preoperatively and on 24th hour postoperatively. During the operation, heart rate (HR), mean arterial pressure (MAP) and SpO2 monitoring was performed.However there have been no intergroup differences observed in preoperative MMSE scores, postoperative MMSE scores were significantly lower in general anesthesia group compared to the other two groups. All 5 (8.1 %) cases whose postoperative MMSE scores under 23, were observed in the general anesthesia group. Have shown a reduction in postoperative scores MMSE and the postoperative scores of MMSE being under 23 have been found to be positively correlated with to be operated under general anesthesia. Preoperative and postoperative mean value of NSE and S100 protein ß was not differ between the groups. All in three groups postoperative values for NSE and S100 ß protein, is significantly higher than preoperative values, but no significant difference between groups has been indicated.As a result of our study; the selected method of anesthesia has an effect on the development of POCD. Regional anesthesia methods have been found more positively related with postoperative improvement on the cognitive functions compared to general anesthesia. A significant difference was not determined among the regional anesthesia techniques in terms of development POCD that we evaluate using change in the MMSE scores.