Failed dural puncture during needle-through-needle combined spinal–epidural anesthesia: a case series

OBJECTIVE: Combined spinal–epidural (CSE) anesthesia is a widely used neuraxial anesthetic technique. In clinical practice, failed dural puncture during needle-through-needle technique occasionally occurs, with incidence of 5%–29%. We radiologically evaluated four cases of failed dural puncture during needle-through-needle CSE anesthesia. CASE SERIES: Four patients received CSE anesthesia for elective orthopedic surgery. CSE procedures were performed in the same manner using a CSE device for needle-through-needle technique. An epidural needle was inserted in midline at L4/5 interspaces using loss of resistance to air whilst patients lay in the lateral decubitus position. The spinal needle was then inserted through the epidural needle for subarachnoid block, however, negative cerebrospinal flow was identified. Subsequently, radiographic imaging using C-arm fluoroscopy was performed to evaluate the status of needles. We found that epidural needles were considerably deviated from the midline, while spinal needles exited epidural needles, not through back holes, but through the Tuohy curve in three patients. In one patient, when the spinal needle was inserted to 12 mm, the anesthesiologist felt the needle touching the bony structure. The spinal needle was in contact with the superior articular process of the fifth lumbar vertebra, which was confirmed by C-arm radiography. CONCLUSION: Excessive paramedian deviation of the epidural needle may affect dural puncture during needle-through-needle CSE technique. Moreover, wrong passage of the spinal needle through Tuohy curve instead of the back hole, may contribute to failure of dural puncture.