Spinal anesthesia is frequently used in clinical practice. It is frequently used in various orthopedic surgeries. It has advantages such as rapid onset of action, cost effectiveness, ease of administration and relatively fewer side effects. Spinal anesthesia has a number of advantages, including quick onset, complete blockade, and little effect on cardiopulmonary- nary function, that make it suitable for use in old age group however, performing spinal anesthesia by landmark-guided approach can be challenging in elderly patients posted for total hip replacement surgery due to lumbar degeneration, moderate to severe arthritis of hip(rheumatoid or post traumatic arthritis).1–4 Spinal anesthesia is widely performed using a surface landmark-based “blind” technique in which

 Multiple   attempts may lead to a higher incidence of  complications  (e.g., postural puncture headache,  paresthesia, hematoma, and infection) and increase  patient discomfort and dissatisfaction.5–7 Spinal anesthesia is conventionally performed using a landmark-guided midline approach. Various modifications have been described to reduce the morbidity related to repeated attempts and passes. These include a pre-procedure ultrasound-guided midline approach, real-time ultrasound-guided approach, landmark-guided Para median approach and pre-procedure ultrasound-guided Para median approach. Ultrasound is beneficial only in patients administered a single shot spinal anesthetic who have difficult surface landmarks or abnormal anatomy. There are insufficient data to support the routine use of ultrasound in all patients.

Therefore, novel techniques are needed to improve the success rate of spinal anesthesia for such patients.

Recently, ultrasound has emerged as a way to facilitate lumbar neuraxial blocks, namely, the ultra- sound assistance (US_AS) technique and the real-time ultrasound guidance (US_RTG) technique. The US_AS technique is beneficial for lumbar neuraxial anesthesia, improving technique performance by providing reliable anatomical information.8–10 Previous studies have shown that pre puncture ultrasound scanning can improve success rates, shorten puncture time, reduce needle passes, and increase the efficacy and safety of lumbar neuraxial blocks.2,11–13 However, a problem with the US_AS approach is that the needle is advanced blindly and sometimes  achieves an ideal trajectory and sometimes not. One possible remedy, reported in recent studies, is the US_RTG technique, which provides real-time observation of the trajectory of the needle during the puncture process.14–17 However, the US_RTG technique is technically difficult to perform. Since few studies comparing the 2 techniques have been done to date, no clear indication exists of which ultrasound technique is more suitable for use in elderly patients posted for Total Hip Replacement (THR) surgery.

Therefore, this study aimed to compare the first- attempt success rate of both the US_AS and US_RTG techniques in elderly patients posted for THR surgery. The first-pass success rate, procedure time, adverse reactions and complications, patient satisfaction, and procedural difficulty score were also compared between the 2 techniques.