Epidural Needle Insertion Simulator A device for training resident anaesthesiologists

To my parents, my sister, and to my wife Epidural anaesthesia is a form of medication injected through patients back into the epidural space of the spine. It is most commonly administered during childbirth and for pain relief following lower body surgery. The procedure involves insertion of a Tuohy needle and a catheter is guided through it into the epidural space 1. Anaesthesiologists insert the needle in between two adjacent spinous processes at an appropriate vertebral level (L2/L3, L3/L4) 1. The needle is passed through five different layers: skin, subcutaneous fat, supraspinous ligament, interspinous ligament, and ligamentum flavum 1. During insertion, varying force is felt at different layers of tissue and a sudden force drop occurs when the needle reaches the epidural space. Once the epidural space is reached, anaesthesiologists stop the advancement of the needle before it reaches the dura (spinal cord). Anaesthesiologists commonly use a syringe filled with air or saline which is attached to the Tuohy needle in order to determine the entry of the needle into the epidural space. This technique is called the loss of resistance (LOR) as the air or saline can be easily injected when the tip of the needle enters the epidural space. After the Tuohy needle is placed in the epidural space, medication is administered through the catheter. The medication blocks the nerve roots and thus the pain in that region of the body. Figure 1.1 The view of the operating room during epidural anaesthesia procedure. The patient is in the sitting position and the anaesthesiologist inserts the needle into the patients back. The epidural anaesthesia procedure is complex and requires knowledge of the anatomy and the procedure (cognitive skills) along with the skills required to perform the same (psychomotor skills). Two of the difficulties in the procedure include needle orientation at a desired angle and careful placement of the needle in the epidural space without dural puncture. Among the complexities, placement of the needle is critical as it involves the risk of damage to the spinal cord. Anaesthesiologists need to learn to place the Tuohy needle in the epidural space by carefully monitoring the varying force felt during needle insertion including the force drop. While experienced anaesthesiologists possess knowledge and proficiency, training of resident anaesthesiologists for competency is fundamental to perform the procedure safely. Currently, in a majority of hospitals, resident anaesthesiologists undergo training on patients. In general the following …