Cerebellar Herniation After Cervical Transforaminal Epidural Injection William A. Beckman, M.D., Robert J. Mendez, D.O., Gregory F. Paine, M.D., and Michael A. Mazzilli, M.D. Objective: The purpose of this study is to inform readers of potential catastrophic complications associated with performing cervical transforaminal epidural steroid injections. Case Report: A 31-year-old man presented to the pain clinic with a history of cervical radicular pain and right upper-extremity radicular symptoms. He was referred from the orthopedic spine clinic for evaluation for epidural steroid injection, having failed conservative treatment consisting of nonsteroidal anti-inflammatory drugs, muscle relaxants, oral steroids, and physical therapy. After undergoing a transforaminal epidural steroid injection at the right C8 nerve root, he developed a cerebellar infarct and brainstem herniation. He survived but has residual deficits of persistent diplopia on right lateral gaze and difficulties with short-term memory loss and concentration. Conclusions: Although transforaminal epidural steroid injections are an efficacious treatment for radicular syndromes, there can be catastrophic complications. In light of the growing body of similar case reports, further investigation is warranted to establish a safe protocol for the use of this modality. Reg Anesth Pain Med 2006;31: 282-285. Key Words: Cervical, Radicular pain, Transforaminal injection, Steroids. C ervical radicular pain in the upper extremities affects 0.1% of the population per year.1 Disc herniation and foraminal stenosis are common causes. After conservative noninvasive therapies have been exhausted, transforaminal epidural steroid injections are a common therapy.2 Complication rates are low and include epidural abscess, intrathecal injection, postdural puncture headache (which can occur if the dural sheath that surrounds nerve root as it leaves spinal canal via the neural foramen is punctured),2 hematoma, nerve injury, spinal cord injury, and arachnoiditis. Recent case reports3,4 have described serious sequelae attributed to this procedure. Here we present a case of cerebellar infarct and brainstem herniation after a right C8 transforaminal steroid injection. From the Naval Medical Center, Portsmouth, VA. Accepted for publication November 29, 2005. The views expressed in this article are those of the author(s) and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. This is a U.S. government work. There are no restrictions on its use. Reprint requests: William Beckman, M.D., Naval Medical Center, Portsmouth, VA, 620 John Paul Jones Circle, Portsmouth, VA 23708-2197. E-mail: WABeckman@mar.med.navy.mil © 2006 by the American Society of Regional Anesthesia and Pain Medicine. 1098-7339/06/3103-0018$32.00/0 doi:10.1016/j.rapm.2005.11.018 282 Case Report A 31-year-old man was referred to the orthopedic spine surgery clinic in September 2001 by his primary care physician with the chief complaint of neck pain and right upper-extremity radicular symptoms. He reported the onset of symptoms 1 day after playing golf approximately 3 weeks before his evaluation. Specific complaints included righthand weakness with writing and paresthesia in the fourth and fifth fingers along with a dull ache over the right triceps. Conservative medical treatment included administration of ibuprofen, cyclobenzaprine, tramadol, naproxen, and diazepam along with physical therapy and a recent short course of oral steroids. His medical history was significant for a history of migraines, which had prevented him from continuing a career as a pilot. The physical examination revealed a positive right Spurling test. (The Spurling test assesses nerve root compression secondary to foraminal narrowing by tilting the head toward the painful side and then applying pressure to the top of the head. If the radicular pain is reproduced, the test is considered positive.) There was decreased strength noted in the intrinsic muscles of the right hand on motor testing. Sensation to light touch was decreased in the right C7 and C8 dermatomes. Deep tendon reflexes were 2⫹/4 Regional Anesthesia and Pain Medicine, Vol 31, No 3 (May–June), 2006: pp 282–285 Cerebellar Herniation at the biceps and brachioradialis bilaterally and 1⫹/4 at the triceps bilaterally. Magnetic resonance imaging of the cervical spine showed a right C7-T1 herniated nucleus pulposus that correlated with the physical findings. The patient was referred to the pain clinic for a course of cervical epidural steroid injections. After verifying nothing by mouth status, allergies, and obtaining informed consent, a saline intravenous lock was placed in the patient’s left arm and the patient was positioned for a transforaminal cervical epidural steroid injection. The patient was placed supine with the head turned to the left and the neck in a neutral position. Monitors were applied (noninvasive blood pressure, electrocardiogram, and pulse oximetry), and the injection site was sterilely prepped and draped. An experienced pain specialist performed the procedure at the right C7-T1 foramen by using a 25-gauge 2 ½-inch short-bevel needle (Kimberly-Clark; Ballard Medical Products, Draper, UT). Sedation was provided by using 50 mg propofol intravenously. Needle position was verified using biplanar fluoroscopy. One milliliter of Omnipaque (iohexol 300 mg/mL; Amsterdam Health, Princeton, NJ) was injected through microbore tubing under continuous fluoroscopy in the posterior-anterior projection. Aspiration was negative, and no vascular uptake was noted. The physician noted good outline of the right C8 nerve root with epidural spread. Sixty milligrams of methylprednisolone (DepoMedrol; Pharmacia-Upjohn, Kalamazoo, MI) was injected along with 0.75 mL 1% lido- Fig 1. Sagittal MRI view showing cerebellar herniation into the foramen magnum. • Beckman et al. 283 Fig 2. Axial MRI view showing right cerebellar infarction. caine but stopped before completion because of patient complaints of neck pain and nonspecific headache. Shortly after the procedure while in recovery, the patient complained of a headache and nausea similar in nature to his migraine headaches and vomited upon sitting up. He was treated with 25 mg promethazine and 30 mg ketorolac intravenously. He remained under observation for the next 2 hours until discharge from the recovery unit by the operative physician. Although transported to his vehicle in a wheelchair, he was able to walk from the wheelchair to his car. Signs of cerebellar injury were not immediately apparent. Later that evening, his wife noticed the patient breathing abnormally. He was transported to the nearest hospital, where, after having periods of apnea and posturing, a computed tomography scan of the brain showed hydrocephalus and right cerebellar areas of reduced attenuation with mass effect and effacement on the fourth ventricle. He had an emergent ventriculostomy followed by magnetic resonance imaging that revealed cerebellar herniation into the foramen magnum (Fig 1) and a right cerebellar infarction (Fig 2). An emergent posterior fossa craniectomy and resection of cerebellar tissue were performed. The postoperative course was complicated by meningitis that was successfully treated. Subsequently, he was transferred to a rehabilitation center in which he made significant improvement. He survived but has residual deficits of persistent diplopia on right lateral gaze and difficulties with short-term memory 284 Regional Anesthesia and Pain Medicine Vol. 31 No. 3 May–June 2006 loss and concentration. He is currently a middleschool teacher. Discussion Cervical transforaminal epidural steroid injections are indicated for the treatment of cervical radicular pain with or without radiculopathy.5 Previously, complications of epidural steroid injections were considered few and minor, including dyspnea, nausea, vomiting, dizziness, hypotension, facial flushing, and transient increase in neck stiffness.4 Recently, there is an increasing awareness of more serious and catastrophic complications. A review of the American Society of Anesthesiologists Closed Claims Project database between 1970 and 1999 revealed 9 deaths or cases of brain damage associated with cervical epidural steroid injections when local anesthetics were used.6 The following similar cases have been reported in the literature: death because of a perforation of the left vertebral artery during transforaminal epidural steroid nerve root block (C7),7 paraplegia after lumbosacral nerve root block,8 and cervical anterior spinal artery syndrome after diagnostic block of C6 nerve root.3 Abram9 opined how difficult it is to know what complications have occurred over recent years as the practice has changed to include more procedures under fluoroscopy and an increase in transforaminal approaches. Currently, many cases that could be reported are in the litigation process.9 A proposed mechanism by which cervical transforaminal epidural steroid injection can cause brainstem herniation is undetected intravascular injection of particulate steroid causing cerebellar infarction with subsequent edema and herniation. A number of factors may have contributed to our adverse outcome. First, our fluoroscopy machine does not have the capability for digital subtraction, which was designed to enhance perception of vessels with contrast. This is achieved by the machine removing (i.e., “subtracting”) background tissue in real time (as determined by pre- and postcontrast images in the picture) that could otherwise distract from and prevent the perception of low-contrast vessels.10 This capability may have detected migration of the injectate. Second, the patient was sedated for the procedure. Hodges et al.4 called attention to the dangers of sedation before performing cervical epidural steroid injections. Such dangers include the patient potentially not being able to verbalize pain or other abnormal sensations that might occur during the procedure and could be indicative of a complication. Third, the patient’s history of migraines confounded the postprocedure evaluation11 because the symptoms the patient was experiencing were described by him as his usual migraine symptoms. If he had these symptoms and did not have the history of migraines, then an immediate, higher level of suspicion for a possible complication may have been present. For such, he would have been hospitalized and observed overnight as well as had a neurologic evaluation and examinations throughout the night. In addition, imaging studies may have been obtained earlier. It is unclear if this would have altered the outcome. In addition, migraines are considered a risk factor for stroke. Fourth, methylprednisolone, a particulate steroid, may have been a contributing factor. A test dose was not used before injection of the steroid solution. Finally, although images of needle placement were not available for review, the clinician performing the procedure was highly experienced and performed the procedure by directing the needle tip to the posterior portion of the foramen midway between the cephalad and caudad aspects of the foramen in the lateral oblique projection and halfway between the medial and lateral aspects of the articular pillars in the posterior-anterior projection. This is described as the desired needle position for transforaminal injections in a recently published atlas.12 Tiso et al.13 recently reported a case of a patient who experienced quadriparesis and brainstem herniation after cervical transforaminal block and presented light microscopic data regarding particle size of corticosteroid preparations along with arterial dimensions. In this study, methylprednisolone and triamcinolone tended to form large aggregates in excess of 100 ␮m that could easily occlude vessels; 8.6% of methylprednisolone acetate aggregates were larger than 50 ␮m and 3.7% of triamcinolone acetonide aggregates were larger than 50 ␮m, whereas no betamethasone aggregates were larger than 50 ␮m. The importance of this is shown by a figure in that study that demonstrates various arterial dimensions such as an arteriole being 10 to 15 ␮m and capillaries being 5 to 8 ␮m.13 In this patient, the most likely mechanism was unrecognized intravascular injection of corticosteroids into the radicular arteries with migration of the embolus to the cerebellar vessels. As a result of this case, our clinic has changed its practice in the administration of transforaminal epidural steroid injections. First, we now use 6 mg betamethasone sodium phosphate 12 mg/mL (New England Compounding Center; Framingham, MA) for all transforaminal injections. The benefits of this steroid preparation include smaller particulate size, lack of large aggregates, preservative-free solution, Cerebellar Herniation and intravenous compatibility. Further studies need to be conducted to determine safety and efficacy differences between different corticosteroid formulations. Second, all patients undergoing transforaminal injections receive additional postprocedure observation and evaluation. Third, we are awaiting 2 new fluoroscopy machines with the capability for digital subtraction. Conclusion We report a case of cerebellar infarction and herniation resulting from a cervical transforaminal epidural injection requiring emergency decompressive surgery. Fortunately, this patient survived. He has residual deficits of persistent diplopia on right lateral gaze and difficulties with short-term memory loss and concentration. Although we have changed our steroid mixture as a result of this case, additional studies are necessary to more fully elucidate causative mechanisms. References 1. Radhakrishan K, Litchy WJ, O’Fallon WM, Kurland LT. Epidemiology of cervical radiculopathy: A population based study of Rochester, Minnesota, 1976 through 1990. Brain 1994;117:325-335. 2. Rathmell J, Aprill C, Bogduk N. Cervical transforaminal injection of steroids. Anesthesiology 2004;100: 1595-1600. 3. Brouwers PJAM, Kottnik EJBL, Simon MAM, Prevo RL. A cervical anterior spinal artery syndrome after diagnostic blockade of the right C-6 nerve root. Pain 2001;91:397-399. • Beckman et al. 285 4. Hodges SD, Castleberg RL, Miller T, Ward R, Thornburg C. Cervical epidural steroid injection with intrinsic spinal cord damage: Two case reports. Spine 1998;23:2137-2142. 5. Rathmell JP, Aprill C, Bogduk N. Cervical transforaminal injection of steroids. Anesthesiology 2004;100: 1595-1600. 6. Fitzgibbon DR, Posner KL, Domino KB, Caplan RA, Lee LA, Cheney FW; American Society of Anesthesiologists. Chronic pain management: American Society of Anesthesiologists Closed Claims Project. Anesthesiology 2004;100:98-105. 7. Rozin L, Rozin R, Koehler SA, Shakir A, Ladham S, Barmada M, Dominick J, Wecht CH. Death during transforaminal epidural steroid nerve root block (C7) due to perforation of the left vertebral artery. Am J Forensic Med Pathol 2003;24:351-355. 8. Houten JK, Errico TJ. Paraplegia after lumbosacral nerve root block: Report of three cases. Spine J 2002; 2:70-75. 9. Abram SE. The safe use of epidural steroid injections. APSF Newsletter Spring 2004:14-15. 10. Pooley RA, McKinney JM, Miller DA. The AAPM/ RSNA physics tutorial for residents: Digital fluoroscopy. Radiographics 2001;21:528-531. 11. Etminan M, Takkouche B, Isorna FC, Samii A. Risk of ischemic stroke in people with migraine: Systemic review and meta-analysis of observational Studies. BMJ 2005;330:63. 12. Rathmell JP. Atlas of Image-Guided Intervention in Regional Anesthesia and Pain Medicine. Philadelphia: Lippincott Williams & Wilkins; 2006:53-56. 13. Tiso RL, Cutler T, Catania JA, Whalen K. Adverse central nervous system sequelae after selective transforaminal block: The role of corticosteroids. Spine J 2004;4:468-474.