Exploring The Application Characteristics Of 6cm Tuohy Epidural Catheter in Labor Analgesia And Chronic Pain

Intervention Therapy Labor Epidural Analgesia is one of the most classic application scenarios of the Tuohy epidural needle at present. For mothers with normal BMI, a lateral position is adopted for puncture at the L2-3 or L3-4 intervertebral space. A 6cm Tuohy needle (usually 17G or 18G) is sufficient to reach the epidural space. In the combined technique of spinal and epidural anesthesia (CSEA), a 25G or 27G Whitacre/Sprotte pencil-point spinal puncture needle is first inserted through the inner cavity of the Tuohy needle to administer medication into the subarachnoid space. After withdrawing the spinal puncture needle, the Tuohy needle is left in the epidural space and a catheter is placed for continuous pump injection of low-concentration local anesthetic + opioids (such as 0.0625% - 0.125% bupivacaine + 2 μg/mL fentanyl) during the labor process. The 6cm short needle is more comfortable to operate on the mother's body and, due to its shallow insertion depth, reduces the probability of accidental puncture of the dura mater (PDPH risk) caused by excessive needle tip penetration - of course, if the mother is obese (with subcutaneous fat thickness > 4cm), an 8-9cm Tuohy needle should be used instead. In the field of chronic pain interventional therapy, the 6cm Tuohy needle can be used for lumbar interlaminar epidural steroid injection (LESI), sacral block (more commonly using modified short needles or dedicated sacral needles), and preoperative establishment of an epidural channel for some nerve ablation procedures. Pain physicians often use imaging (C-arm or ultrasound) to guide and confirm the needle tip position. The 6cm Tuohy needle is still applicable in the lumbar-sacral segment of patients with slender body types. Some centers also use the Tuohy needle for establishing a channel during paravertebral block and then performing continuous drug administration, or as an external dural puncture probe for the spinal canal drug infusion system (IDDS) implantation procedure. It is worth noting that in pain intervention, if it is necessary to pass through thicker soft tissues or encounter calcified ligaments, a longer needle may be required, but a 6cm short needle is usually prepared initially to assess the depth. In terms of nursing cooperation, the patient's position should be adjusted to fully flex the hips and knees to open the intervertebral space; strict aseptic dressing and disinfection should be carried out; assist in connecting the LOR injection device and observe the changes in the liquid column; after catheter placement, firmly fix it and mark the insertion depth; during the operation of the analgesic pump, regularly assess the sensory/motor block plane and vital signs. For labor analgesia, the catheter inserted by the 6cm Tuohy needle is generally left in the epidural space for 4-5 cm. It is fixed with an "L" shape adhesive tape and connected to the analgesic pump. After the labor process is completed, first clamp, assess, then remove it. Press the puncture point to prevent subcutaneous hematoma. Overall, due to its moderate length and good controllability, the 6cm Tuohy needle is one of the commonly selected needles for obstetric anesthesia and outpatient pain intervention procedures in the lumbar region.