Comparative study of traditional lumbar subarachnoid block vs novel thoracic subarachnoid block for cesarean section: A randomised single blinded trial

Cesarean delivery is one of the most common surgeries performed globally.Neuraxial anaesthesia is preferable to general anaesthesia for cesarean delivery as it is associated with less maternal and neonatal morbidity and mortality. Traditionally, spinal anaesthesia is administered in the lumbar region to avoid spinal cord injury. Recent MRI studies indicate a more substantial depth of the posterior subarachnoid space in the thoracic spinal cord and therefore showed no neurological sequelae at the thoracic level, and the incidence of paresthesia was similar to that seen at the lumbar level. The total amount of CSF in the thoracic segment is less when compared to the lumbar and cervical segments, causing easy blockade of roots and a reduction in the dose of the drug required, along with improved muscle relaxation. During lumbar spinal anaesthesia, the sympathetic blockade extends to the lower limbs resulting in vasodilation of the blood vessels and reduction in preload. During thoracic spinal anaesthesia, the sympathetic block is restricted to fewer dermatomes with minimal involvement of the lower limbs, therefore, a smaller reduction in preload and blood pressure is seen. Thoracic segmental spinal anaesthesia has been gaining popularity in recent times and has been successfully performed for abdominal cancer surgeries, breast surgeries, laparoscopic cholecystectomies, and nephrolithotomies. In pregnant females posted for cesarean section, thoracic spinal anaesthesia helps in early mobilisation postoperatively, which meets the goals of enhanced recovery after surgery (ERAS). It also helps with the early initiation of breastfeeding, ensuring that the infant receives colostrum while facilitating the emotional bonding between the mother and the baby. We are thus conducting this study to explore the effectiveness of performing thoracic segmental spinal anaesthesia in patients posted for elective cesarean surgery under neuraxial blockade