Comparison of Ultrasound-assisted versus Landmark-guided Subarachnoid Block in Patients of Ankylosing Spondylitis Undergoing Total Hip Replacement: A Prospective Randomized Trial.

BACKGROUND AND AIMS: Ankylosing spondylitis (AS) poses considerable challenges for anesthesiologists due to its effect on spinal anatomy and potential airway difficulties. The characteristic ossification and vertebral fusion - commonly referred to as a "bamboo spine" - leads to rigidity and impaired spinal mobility, often complicating neuraxial anesthetic techniques. This study aimed to assess whether a preprocedural ultrasound-assisted approach improves the success rate of dural puncture with fewer needle attempts compared to the traditional landmark-guided technique in patients with altered spinal anatomy due to AS.

METHODOLOGY: Sixty American Society of Anesthesiologists physical status I and II patients aged 18-60 years with AS, scheduled for elective total hip arthroplasty, were enrolled and randomly divided into two equal groups. Group I received ultrasound-assisted subarachnoid blocks, whereas Group II underwent the conventional landmark-based approach. Hemodynamic parameters, total number of needle attempts, and the time required to administer the block were recorded. The primary outcome was the number of attempts for successful dural puncture. Secondary outcomes included time taken and postprocedural complications.

RESULTS

Group I (ultrasound-guided) demonstrated a significantly higher first-attempt success rate compared to Group II. Although the ultrasound method showed a slightly increased procedural duration, the difference was not statistically significant, and postprocedural complications were comparable.

CONCLUSION

Ultrasound guidance notably improves first-pass success rates for subarachnoid block in patients with AS, making it a valuable technique for spinal anesthesia in such cases.