The use of sonographic guidance in caudal epidural steroid injections

Transverse plane ultrasound-guided caudal epidural injections: sonographic anatomy and stepwise technique

PURPOSE

The present study aims to provide a step-by-step procedural and anatomical familiarization guide for transverse plane ultrasound (US)-guided caudal epidural (CE) injection.

METHODS

The study cohort consisted of 23 chronic low back pain patients (23-67 years old) previously unresponsive to conservative management. A transverse plane US-guided CE injection was performed, with each procedure step documenting and emphasizing sonographic anatomy. Several Thiel's method fixed cadaveric specimen dissections were also performed to demonstrate relevant CE injection-related anatomy.

RESULTS

The sacral hiatus location can be estimated by visually forming an equilateral triangle between the posterior superior iliac spines and the sacral apex (trigonum sacrale). Follow-up palpation locates the sacral cornua, guiding transducer placement visualizing over the paired cornua 'bull frog's eye's appearance, with the epidural space visualized as a hypoechoic line, between the eyes. Then, 2-3 ml of 1% lidocaine is injected subcutaneously at the mid-point between the sacral cornua and superficial to the posterior sacrococcygeal ligament (SCL). Although keeping the cornua, superficial posterior SCL and epidural space in view, the needle is slowly advanced to the epidural space at around a 20 degree cephalad angle till the tip becomes visible. Expansion of the epidural space is monitored under the transverse sacral ligament as the injectant is slowly introduced.

CONCLUSION

The present study demonstrated the anatomical landmarks necessary for the transverse ultrasound caudal epidural technique and that the cornua, superficial posterior SCL, CE space, and other relevant sacral hiatal anatomy are well visualized with this technique.

Preprocedural Ultrasonography Versus Landmark-Guided Spinal Anesthesia in Geriatric Patients with Difficult Anatomy: A Prospective Randomized Trial

Objective

This study was aimed to determine whether preprocedural ultrasonography (USG) affects the technical performance of spinal anesthesia in elderly patients with difficulty in palpating landmarks, scoliosis, or previous spine surgery.

Materials and Methods

This prospective study was conducted in 156 elderly patients scheduled for elective orthopedic lower extremity surgery. The patients were randomly divided into 2 groups to receive spinal anesthesia by the preprocedural USG examination (group U) or conventional landmark palpation technique (group P). The primary finding of our study was the rate of successful access to the subarachnoid space on initial needle insertion attempt. Secondary achievements included number of needle insertion attempts, number of needle redirections, total procedure time, needle pain scores, patient satisfaction, and complications of spinal anesthesia.

Results

The rate of successful access to the subarachnoid space at the first needle insertion attempt was significantly higher in group U than in group P (74.4% vs 53.8%, p=0.008). Medians (interquartile range) of both needle insertion attempts (group P, 2 [1-3] vs group U, 1 [1-2]; p=0.038) and needle redirections (group P, 3 [2-5] vs group U, 2 [1-4]; p=0.028), requiring to achieve dural puncture, were significantly higher among the patients in group P than those in group U. No statistically significant difference was found between the groups regarding total procedure time, pain scores, patient satisfaction scores, and spinal anesthesia-induced complications (p>0.05).

Conclusion

Our study findings showed that preprocedural neuroaxial USG improves technical performance of spinal anesthesia in elderly patients with difficult anatomy.