Real-time ultrasound guided thoracic epidural catheterization: a technical review

Thoracic epidural analgesia (TEA) is known to have superior perioperative pain control over intravenous (IV) opioid analgesia in open abdominal surgery and is an essential enhanced recovery after surgery (ERAS) component in major abdominal surgeries. Recently, the ultrasound-guided thoracic epidural catheter placement (TECP) technique has drawn attention as an alternative for the traditional landmark palpation-based TECP or fluoroscopic-guided TECP technique due to the equipment’s improvement and increased popularity. However, only a small number of studies have introduced the advantages and usefulness of ultrasound-guided TECP. Moreover, a certain level of ultrasound-guided in-plane technique is required to perform this technique. Thus, to apply ultrasound-guided TECP correctly and reduce the likelihood of side effects and complications, the practitioner must have a thorough understanding of the anatomical region, optimal block positioning, device selection, and management. In this technical review, the authors have compared the advantages and disadvantages of ultrasound-guided TECP to traditional techniques and described its technical aspects from patient positioning, ultrasound probe selection and scanning, needle insertion under ultrasound guidance, and successful thoracic epidural catheter insertion confirmation through ultrasound imaging. Additionally, the recommended epidural catheter tip placement level with the extent of its injectate epidural spread is further described in this review in reference to a recent prospective study published by the authors.

Knot formation in a thoracic epidural catheter: a case report

Background Although most epidural catheter knot formation has been reported in lumbar epidural catheter placement, knot formation in a thoracic epidural catheter has been experienced. Case presentation A 72-year-old woman was scheduled for laparoscopic cholecystectomy under general anesthesia combined with epidural anesthesia. The epidural catheter was inserted through the Th10–Th11 intervertebral space and was placed 7 cm into the epidural space. Two days after the surgery, the anesthesiologist was called because of difficulty in removing the epidural catheter. The catheter was eventually removed when the anesthesiologist carefully pulled it while strongly bending the patient’s body to the right, although resistance was still noted. The removed catheter was observed to have a hard single knot formed at about 3 mm from the tip. Conclusions A knot formation of an epidural catheter placed at the thoracic level was experienced. Limiting the length of catheter placement may prevent knot formation.

Real-time ultrasound-guided low thoracic epidural catheter placement: technical consideration and fluoroscopic evaluation

Background and objectiveThoracic epidural analgesia can significantly reduce acute postoperative pain. However, thoracic epidural catheter placement is challenging. Although real-time ultrasound (US)-guided thoracic epidural catheter placement has been recently introduced, data regarding the accuracy and technical description are limited. Therefore, this prospective observational study aimed to assess the success rate and describe the technical considerations of real-time US-guided low thoracic epidural catheter placement.Methods38 patients in the prone position were prospectively studied. After the target interlaminar space between T9 and T12 was identified, the needle was advanced under real-time US guidance and was stopped just short of the posterior complex. Further advancement of the needle was accomplished without US guidance using loss-of-resistance techniques to normal saline until the epidural space was accessed. Procedure-related variables such as time to mark space, needling time, number of needle passes, number of skin punctures, and the first-pass success rate were measured. The primary outcome was the success rate of real-time US-guided thoracic epidural catheter placement, which was evaluated using fluoroscopy. In addition, the position of the catheter, contrast dispersion, and complications were evaluated.ResultsThis study included 38 patients. The T10–T11 interlaminar space was the most location for epidural access. During the procedure, the mean time for marking the overlying skin for the procedure was 49.5±13.8 s and the median needling time was 49 s. The median number of needle passes was 1.0 (1.0–1.0). All patients underwent one skin puncture for the procedure. The first-pass and second-pass success rates were 76.3% and 18.4%, respectively. Fluoroscopic evaluation revealed that the catheter tips were all positioned in the epidural space and were usually located between T9 and T10 (84.2%). The cranial and caudal contrast dispersion were observed up to 5.4±1.6 and 2.6±1.0 vertebral body levels, respectively. No procedure-related complications occurred.ConclusionReal-time US guidance appears to be a feasible option for facilitating thoracic epidural insertion. Whether or not this technique improves the procedural success and quality compared with landmark-based techniques will require additional study.Trial registration numberNCT03890640.