The Effect of Operating Table Tilt on Ultrasonographic Ligamentum Flavum Measurements and Block Success Prior to Spinal Anesthesia in Pregnant Patients

Objective: During pregnancy, changes occur in vertebral anatomy as well as maternal physiological changes that occur in every system. The aim of this study is to compare the ligamentum flavum (LF) lengths and the success rates of spinal interventions made from the longest LF interval of pregnant women in neutral and 10° lateral tilt positions with measurements from different vertebral levels using preprocedural ultrasonography in cesarean neuraxial anesthesia. Methods: The study was carried out with 50 pregnant patients who were scheduled for cesarean section under spinal anesthesia after the approval of the local ethics committee. The patient was seated sideways with her feet hanging down. When the lateral tilt angle of the table is 0° and 10° measurements were made at L3-L4 and L4-L5 levels. Ligamentum flavum, skin-LF distance and interlaminar space were measured. Afterwards, spinal anesthesia was performed at the longest measurement level of LF and at the table angle. Results: At the L3-L4 and L4-L5 levels, LF lengths at 0° table tilt were compared with the LF lengths at 10° lateral tilt position, a significant increase was observed at 10° (p=0.001, p=0.001). According to the condition of applying spinal anesthesia from the angle and interval where the LF is the longest in the study; 54% of the procedures were performed in the L3-L4 level 10° lateral tilt position and 46% of the procedures were performed in the L4-L5 level 10° lateral tilt position. In the 10° lateral tilt position, there was no difference between the L3-L4 and L4-L5 intervals between the number of trials and needle guidance. Conclusion: As a result, using preprocedural vertebral ultrasound and 10° lateral tilt in neuraxial procedures in pregnant women will allow to easily determine the longest interval of LF and to perform successful neuraxial anesthesia with the least number of attempts. Keywords: Anesthesia spinal, pregnancy, ligamentum flavum, neuraxial, ultrasonography