Comparison of the depth of Subarachnoid space using anthropometric measurements, ultrasonographic measurements and actual depth by needle insertion in a patients with BMI more than 25kg/m2

**:**Multipleattempts during subarachnoid block can result in complications like post duralpuncture headache, lower back pain and cause discomfort to the patient, apartfrom being time consuming. Although, anatomical knowledge and technicalskills are important, presumed prearrangement of the skin to subarachnoid spacedepth (SSD) may lead to the correct placement of the spinal needle. This allowsfor less traumatic and fewer repetitive attempts for spinal anesthesia. Thepalpation of bony landmarks required to successfully perform lumbar punctures(LPs) can be masked in 33% of overweight patients and 68% of patients withobesity, due to overlying soft tissue and can lead to LP failure rate of 19%. In a patient, the SSD varies considerably at different levels of thespinal cord. It also varies from patient to patient at the same vertebral levelas per age, sex and body mass index (BMI).

The rationale behind doing this study is to assess whichmethod is more accurate to determine the SSD so as to minimize repeatedattempts for spinal anaesthesia especially in overweight patients.

Thestudy is going to assess the SSD in a population with BMI>25kg/m2 withanthropometric measurements, ultrasonography and actual depth by needleinsertion.