Periosteal entrapment of an epidural catheter in the intrathecal space.

Abstract

A 25-yr-old woman, 160 cm tall, 113.6 kg, gravida-3, para-0 at 40 wk gestation was admitted in active labor at 3-cm cervical dilation. Her medical history was unremarkable. She elected to receive an epidural for labor analgesia. The patient was placed in the sitting position, and a midline approach was attempted at the L3-4 intervertebral space using the Arrow Flextip kit (Arrow International, Inc., Reading, PA). The 17-gauge Hustead needle was inserted 6 cm to reach the epidural space, but the catheter met resistance and would not pass despite needle rotation, needle repositioning, or dilating the space with saline. A second anesthesiologist attempted a midline insertion at the L2-3 intervertebral space. The Hustead needle was inserted 6 cm to reach the epidural space and the Arrow Flextip catheter was advanced 8 cm into the epidural space. Resistance was encountered when the anesthesiologist attempted to pull the catheter back to the 10-cm mark on the skin surface, which would have left 4 cm of catheter in the epidural space (our standard practice). Further attempts to pull the catheter back were abandoned. The catheter was secured with sterile dressing at 16 cm on the skin surface. After negative aspiration of blood or cerebral spinal fluid from the catheter, a 3-mL test dose of lidocaine 1.5% with 1:200,000 epinephrine was administered. The patient complained of lower motor extremity weakness and numbness. She was placed in the supine position with left uterine displacement. The block rapidly ascended to the T1-2 dermatome level. Her blood pressure decreased from 106/56-mm Hg to 84/44-mm Hg. She received a rapid IV infusion of lactated Ringer’s solution and ephedrine was titrated in 5-mg increments to maintain systolic blood pressure more than 100 mm Hg. During this episode, the fetal heart rate remained more than 135-bpm. Her blood pressure, heart rate, and oxygen saturation were monitored until the block regressed to a T4 level. No further injection of local anesthetic was required while she remained in active labor. Four hours after catheter placement, a cesarean delivery was planned as a result of arrest of cervical dilation. The intrathecal catheter was dosed with 2 mL of hyperbaric spinal bupivacaine 0.75% in divided doses over 10 min. The block reached a T-4 dermatome level bilaterally. The cesarean delivery proceeded uneventfully and a healthy neonate was delivered. Postoperatively, when the patient regained full lower extremity sensation, we unsuccessfully attempted to remove the catheter. All attempts to remove it with the patient’s spine positioned in different degrees of flexion and extension in both sitting and lateral position were futile. Because the catheter was trapped in the intrathecal space, neurosurgical consultation was obtained. A computerized tomography scan of the spine, obtained to determine catheter location and to eliminate nerve entrapment, showed the catheter tip in the intrathecal compartment (Fig. 1). Nerve entrapment was not evident. The catheter appeared to lie in close proximity to the periosteum of the vertebral body (Fig. 2), which was felt to be the source of entrapment. The neurosurgeon extracted the catheter 0.5-cm at a time, holding it with a pair of hemostats and applying gentle traction with another pair placed as close to the skin as possible. The neurosurgeon succeeded in removing the catheter, possibly because the hemostats enabled him to apply a firmer grip and a steady incremental pull. A picture of the removed catheter is shown in Figure 3. The distal 5 cm did not show visible areas of surface damage (Fig. 3). However, the stretched catheter revealed surface damage and disruption of the internal flexometallic ring between 5 and 15 cm (Fig. 3). The patient received IV ceftriaxone and vancomycin. She remained afebrile, and the remainder of her hospital course was uneventful.