Effect of Spinal Anesthesia on Postoperative Cognitive Dysfunction

Background: It seems that spinal anesthesia is an appropriate approach for elderly patients and those who are not suitable candidates for general anesthesia. This study aimed to determine the effect of spinal anesthesia on postoperative cognitive decline in elderly patients.

Methods: This cross-sectional study was performed on 81 patients older than 65 years of age with the ASA classes I and II. The cases were candidates for surgery and spinal anesthesia and referred to Besat Hospital, Hamadan, Iran. Moreover, they receive surgical treatment and underwent spinal anesthesia from 2019 to 2020. Wechsler Memory Scale-III (WMS-III) was utilized to compare the cognitive dysfunction in elderly patients before and after spinal anesthesia. Furthermore, the WMS-III scores were compared before and after anesthesia to assess the severity of cognitive dysfunction, short- and long-term memories, as well as concentration rate at discharge.

Results: According to the results, there was no significant difference before and after spinal anesthesia regarding the mean mental control, repetition, visual reproduction, and verbal paired associates (P>0.05). Moreover, the mean values of spatial addition (Z=-2.07; P=0.03) navigation (Z=-2.13; P=0.03), and logical memory (Z=-2.42; P=0.01) increased after spinal anesthesia. In addition, the mean values of the memory coefficient were estimated at 68.28±16.77 and 68.66±16.94, respectively. The comparison of memory coefficient among elderly patients undergoing spinal anesthesia showed no significant difference before and after spinal anesthesia (Z=-1.51; P=0.13). A reverse correlation was reported between age and memory coefficient before (r=-0.46; P<0.005) and after spinal anesthesia (r=-0.405; P<0.005).

Conclusion: Spinal anesthesia had no effects on memory coefficient. However, there was an increase in some memory function domains, including spatial addition, navigation, and logical memory after the operation. The memory scores may have been affected by the patients' conditions before the operation.