Epidural steroid injection is commonly performed for back pain resulting from acute lumbar disk herniation (1), lumbar canal stenosis (2), radiculopathy, and lumbago sciatica pain (3,4). A wide array of temporary and permanent neurological complications has been reported during attempted epidural injection including cauda equina syndrome (5), sciatic nerve palsy (6), transient paraplegia (7), quadriplegia, brain damage, or death (8). Neurological sequelae may result from infection, hemorrhage, trauma, accidental intrathecal injection, or allergic reaction (9). Intracord injections have mainly been reported in patients in whom epidural block was given either under anesthesia or deep sedation (10–12). We report a case of permanent paraplegia in a conscious patient after accidental intracord injection during attempted epidural steroid injection using fluoroscopy.
A 62-yr-old male patient weighing 78 kg presented to the pain clinic with backache. As the magnetic resonance imaging (MRI) of the spine excluded any compressive spinal cord lesion, orthopedicians recommended epidural steroid injection. The pain had the distribution of T12 to L3 nerve roots characteristically aggravated on bending. The T11–12 intervertebral space was infiltrated with lidocaine (1%) 2 mL without sedation. Under fluoroscopy using aseptic technique, the epidural space was identified with an 18-gauge Tuohy needle at the T11–12 intervertebral space using a loss-of-resistance technique. The Tuohy needle once contacted the laminae and was redirected 15° cephalad to enter the epidural space as above. A test dose of 3 mL of 1.5% lidocaine with epinephrine was injected. The patient showed neither hemodynamic change nor weakness and after 3 min, triamcinolone (40 mg) in 10 mL of bupivacaine (0.125%) was administered through the needle.
The patient noted pain relief in 5 min. Although he could move his toes bilaterally the weakness in his limbs remained undetected because of his restricted mobility after hip joint fixation and weakness. We looked for the dorsiflexion of the great toe in both the lower limb and the presence of planter reflex. As the patient had no pain and was also hemodynamically stable, he was discharged. The next day at home during physiotherapy, the patient was unable to move either leg and his strength was still “0” after 30 h. Sensory loss up to T10 was also detected with loss of bladder and bowel control.
MRI of the spinal cord performed 36 h after the epidural injection demonstrated hyperintensity in the spinal cord extending from T9 vertebra to conus with cord swelling on T2-weighted images (Fig. 1). On post-contrast study there was focal enhancement of the dura at T11–12 level consistent with intracord injection. The patient was managed conservatively with a bladder training program and physiotherapy including passive movements of his lower limbs. However his deficits did not improve over 4 mo.
Epidural injection of corticosteroids is performed at the lumbar, thoracic, and cervical levels. Neuroaxial steroid injections are generally considered to be safe; however, the incidence of epidural steroid-related complications is difficult to judge. However, in the ASA closed claim study for chronic pain, 40% of claims were associated with the injection of epidural steroids (n = 114), reflecting the frequency of these procedures (8). Of the 18 claims for paraplegia or quadriplegia after epidural blocks, 4 were associated with epidural abscess, 8 with chemical injury in which the anesthetic or neurolytic drug was injected into the spinal cord, and 4 with hematoma.
Intracord injection and permanent quadriplegia have been reported in a patient who had undergone laminectomy and the epidural catheter was placed under general anesthesia (10). Hodges et al. (12) reported two cases of nerve injury after cervical epidural steroid injection performed in heavily sedated patients using fluoroscopy. In both patients, injury to the cord was evident on MRI. In another closed claim study of two patients reviewed by Abram and O’Connor (13), the cervical epidural steroid injection was performed under fluoroscopy in a deeply sedated patient. In the second patient a lumbar epidural steroid injection was performed without fluoroscopy and the patient suffered severe motor and sensory loss in one leg, with the MRI showing a lesion in the conus. In our patient, even fluoroscopy could not prevent intracord injection. It seems fluoroscopy guidance may not prevent intrathecal perforation or spinal cord penetration.
All of these major complications of intracord injections were reported in patients who were either anesthetized or under heavy sedation. However, our patient did not receive sedation at the time of epidural block under fluoroscopy. In a conscious patient, it is usually believed that the patient will react to the needle touching the nerve roots or cord or piercing the dura. In our patient, however, intracord placement of the epidural needle not only provoked no patient response but remained unnoticed during needle insertion under fluoroscopy. Possibly our patient, already in pain, failed to notice the new pain of the needle piercing the dura and the spinal cord. We did not notice tingling or weakness in the lower limbs even during test dose injection, which should elicit immediate numbness. The concentration of bupivacaine (0.125%) was likely too small to cause neurotoxicity that may have been related to the polyethylene glycol vehicle.
Early detection and decompression of the cord has been reported to give a better outcome and recovery after epidural hematoma (14). However, without a hematoma, surgical intervention is debatable. In our pain clinic, usually after the epidural block, we discharge the patient home once he or she attains hemodynamic stability and begins limb movement. Because in this patient his lower limb movements were restricted and the dorsiflexion of the great toe was positive, we discharged the patient. This contributed significantly to the delay in detection of paraplegia. As result of this case, we have now changed our discharge criteria to complete recovery of lower limb weakness after epidural steroid injection.
Interestingly, injection of local anesthetic, opioids, or both occurred in 61% of the 114 epidural steroid injection claims with death or brain damage. Therefore, ASA Closed Claims Project data demonstrated that serious injuries can occur with epidural steroid injections when combined with local anesthetics and opioids. Considering these findings, we propose that patient safety can be improved by excluding typical epidural doses (volumes in excess of intrathecal test doses) of local anesthetics and/or opioids from epidural steroid injections (8). In our patient we used the normal epidural injectate volume (10 mL) of local anesthetic along with the steroid dose. The accidental intracord injection caused widespread spinal cord swelling from T9 to conus, extensive paraplegia, and the bladder and bowel involvement.
In 6 of 9 patients with serious deficits, their complication was noted soon after injection (8) but it was delayed in our patient as we discharged him earlier because of his hemodynamic stability and dorsiflexion of the toe. In our pain clinic we now strictly recommend a close observation in the immediate postblock period until the recovery of muscle strength in the limbs and the use of a smaller concentration and volume of a short-acting local anesthetic. In conclusion, we wish to remind pain practitioners of the possibility of this catastrophic event even in conscious patients and while using fluoroscopy as well.
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