Case Reports: Case Report
Thoracic endovascular aortic repair (TEVAR) has been performed with increasing frequency since the technique was first described in 1994.1,2 TEVAR for aortic aneurysms or dissections offers numerous advantages over open repair, including reduced intensive care unit stay, reduced hospitalization, and lower 30-day mortality. In a study of over 11,000 patients with thoracic aortic aneurysms, dissections or rupture TEVAR had a lower perioperative mortality rate than open repair (7.4% vs 18.5%).3
One of the major risks of TEVAR is spinal cord ischemia leading to permanent paraplegia. Paraplegia rates after TEVAR vary but are anywhere from 1% to 4%.4,5 Factors associated with paraplegia include the length of aorta covered, coverage of the artery of Adamkiewicz, and hypotension. A critical intervention for reducing paraplegia risk is cerebrospinal fluid (CSF) drainage, which has been shown to decrease paraplegia risk by as much as 55%.6,7 CSF drainage has low risks of hemorrhage or infection.8 To our knowledge, there are no published reports describing the management of entrapped lumbar drains. In this case report, we describe the management of an entrapped drain and strategies that facilitated its removal. The patient gave written consent for us to publish this report.
A 52-year-old, 80-kg man with a history of end-stage renal disease and a previous ascending aortic replacement was admitted with hypertensive emergency and a type B dissection from the left subclavian artery to the aortoiliac bifurcation. His blood pressure was controlled using a continuous esmolol infusion and IV labetalol boluses. On his fifth hospital day, he was scheduled for TEVAR. A decision was made to place a lumbar drain for spinal cord protection. Placement of the drain was performed after induction of general anesthesia with the patient turned into the left lateral decubitus position. Drain placement was difficult in part because of the patient’s muscular physique. Three attending anesthesiologists attempted placement but were unsuccessful in reaching the subarachnoid space even after repositioning the patient and attempting placement via a different spinal interspace. Ultimately, the lumbar drain was placed using fluoroscopic guidance by an attending anesthesiologist with interventional pain management training. The anesthesiologist entered the subarachnoid space via the L4–L5 spinal interspace using a right paramedian technique and a 17-gauge Tuohy needle, but despite having excellent CSF flow, there was difficulty passing a standard 1.5-mm outer diameter lumbar drain. Ultimately, a 19-gauge styleted peripheral nerve catheter was passed successfully through the Tuohy needle and into the subarachnoid space. The catheter was secured at 25 cm.
The patient had an uneventful surgery, had normal fluid drainage, and a normal neurologic examination after surgery. On the second postoperative day, the surgeon requested drain removal. Drain removal was attempted with the patient in the right lateral decubitus position and the lumbar spine flexed, but the drain appeared to be entrapped. During attempted removal, the patient experienced severe neuropathic pain in the L4 dermatomal distribution (left hip) and had severe muscle spasms in his erector spinae and vastus lateralis muscles. After several unsuccessful attempts to remove the drain, a decision was made to obtain a computed tomography (CT) scan of the lumbar spine. Muscle spasms were treated with 5 mg IV diazepam, and 4 mg IV dexamethasone was administered to treat possible edema near the L4 nerve root canal.
CT scan (Figures 1 and 2) revealed that the drain entered the spinal canal above the L5 lamina and was entrapped between the L5 lamina and the inferomedial aspect of the L4 articular process. CT also showed that the drain took a circuitous path through the skin and subcutaneous tissue passing from the patient’s right to his left side where it entered the spinal canal. There was no evidence of nerve root entrapment or knotting of the catheter.
Based on the CT scan, a decision was made to attempt drain removal with some modifications. If the drain was unable to be removed after these modifications, the plan was for open surgical removal. The patient was turned into the right lateral decubitus position and placed into extreme lumbar spine flexion. The patient’s lumbar drain was prepped with chlorhexidine gluconate so that stylet replacement could be performed if necessary and general anesthesia was induced briefly using an IV propofol bolus of 80 mg. An attempt was made to remove the drain after induction of general anesthesia. We were able to pull the drain back slightly (1–2 cm) but were not able to remove it fully. For this reason, the stylet from a new peripheral nerve catheter kit (the same kit that was used for initial insertion) was sterilely replaced into the drain with only slight resistance over the course of approximately 1 minute. With these interventions, the drain was successfully removed using a downward pull (toward the patient’s right side) rather than a straight pull. The patient recovered without complications.
Lumbar drain placement has been performed with increasing frequency by anesthesiologists. These drains play a critical role in spinal cord protection during TEVAR but have associated risks. In a cohort of 65 patients having lumbar CSF drainage, Weaver et al8 reported a 3.2% rate of intraspinal hemorrhage and no infectious complications or mechanical complications. In a prospective cohort of 56 patients, Hnath et al9 reported zero complications with lumbar drains. To our knowledge, there are no published reports describing the management of an entrapped drain. There is a published case series of 5 patients who had fractured CSF catheters.10 In this series, 4 of 5 patients required surgical removal of the fractured catheter. Excessive force during removal was cited as a risk factor for catheter fracture.
In our patient, CT imaging was extremely helpful in delineating the cause of drain entrapment. Three-dimensional reformatting was particularly useful in showing where the drain was entrapped. It also helped to explain why the anesthesiologist who placed the drain was initially unable to enter the spinal canal without using a stylet. CT imaging also ruled out a knot in the drain, intrathecal or epidural hemorrhage related to previous removal attempts, and entanglement of the drain around a nerve root.
Induction of general anesthesia facilitated drain removal in our patient, because he had severe muscle spasms in his erector spinae and vastus lateralis muscles during initial removal attempts. Flexing the patient’s lumbar spine to the maximum possible degree helped to open the L4–L5 articular process where the drain was entrapped. Our decision to replace the stylet was difficult, because this intervention increases the risk of drain fracture and may also increase the risk for infection even when a sterile technique is observed. We believe replacing the stylet facilitated removal by helping to straighten and stiffen the drain. Finally, CT imaging helped to show which direction the drain curved beneath the skin and in the subcutaneous tissues. This information allowed us to change our approach from pulling the drain straight back to pulling it down (toward the patient’s right side). It is unclear why the drain had a circuitous path in the subcutaneous tissue. One possibility is that because the drain was placed under general anesthesia, there was a different degree of muscle relaxation compared with the awake state. Repositioning of the Tuohy needle in the subcutaneous tissue and the angulation of its tip may also have contributed to the drain’s circuitous path.
In summary, we report a case of a lumbar drain that was entrapped between the L5 lamina and the inferior articular process of L4. CT of the lumbar spine with 3-dimensional reformatting was critical in understanding where the drain was entrapped and what interventions could facilitate removal. Based on our experience in this case, we recommend that providers obtain CT imaging of the lumbar spine with 3-dimensional reformatting and induce general anesthesia to facilitate removal of an entrapped drain. Careful replacement of the stylet into the drain might also be considered if other interventions fail.
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