Epidural Granuloma and Intracranial Hypotension Resulting from Cervical Epidural Steroid Injection

A previously healthy 39-yr-old woman presented with a 2-week history of lower neck pain radiating to the left axilla and across the left side of the chest. Initial therapy consisted of tapering use of oral methylprednisolone, cyclobenzaprine, and valdecoxib. One week later, the patient experienced numbness of the left hand. Magnetic resonance imaging (MRI) revealed a herniated disc at C6–C7, with protrusion into the left C7 axillary sleeve.

The patient underwent a series of three CESIs, each 2 weeks apart, over the next 6 weeks at an outside hospital. According to the medical records and patient recollection, all the blocks were performed at the C6–C7 interspace, with the patient sitting upright and with use of an 18-gauge Tuohy needle. The neck was flexed and independent of support. Sedation was with 3 mg intravenous midazolam. The needle was inserted and advanced using a hanging drop technique. Fluoroscopy was used. Results of aspiration were negative for blood and cerebrospinal fluid (CSF). Contrast was injected, followed by 0.5% lidocaine and 60 mg triamcinolone, for a total volume of 5 ml, for the first two blocks.

Within a week after the first block, the patient experienced headaches, night sweats, and constant upper cervical neck pain. During the third and final block, the patient experienced a “lightning-bolt” type pain radiating down the outer aspect of the right shoulder, elbow, and fingers. The needle was promptly withdrawn, and the pain resolved. The needle was then readvanced in the same interspace, and the block was performed with 0.5% lidocaine and 80 mg triamcinolone, for a total volume of 5 ml.

Over the next 6 weeks, the patient’s condition worsened. The headache and upper cervical pain became severe, and upper extremity tremor, facial flushing, upper extremity weakness, hyperreflexia of all extremities, and numbness over the anterior aspect of both thighs developed. MRI showed a fusiform anterior epidural mass effacing the thecal sac, causing mild posterior displacement of the spinal cord, with prominent distension of the epidural venous plexus. The mass enhanced with gadolinium (fig. 1; 1 month after the third epidural injection).

The patient was admitted to the hospital. Blood culture results were negative. Vertebral angiography results revealed prominent veins in the anterior epidural space in the upper cervical spine but were otherwise normal. There was no evidence of dural sinus thrombosis or arteriovenous malformation. Antibiotic therapy was initiated with intravenous vancomycin and ceftriaxone and oral metronidazole and continued for 1 month. Tapering oral methylprednisolone was given.

Headaches and neck pain were treated over the next 4 months with a variety of medications, including fentanyl patch and oral diazepam, and tapered to acetaminophen–propoxyphene and valdecoxib. The patient continued to experience headaches and had decreased hearing in the left ear, upper extremity tingling, and numbness. Three months later, the headaches became incapacitating and were associated with nausea. The headaches were notably worse in the sitting and standing positions.

A brain MRI with and without contrast revealed extensive uniform enhancement of the pachymeninges, prominence of cavernous sinuses, increased volume of the pituitary gland, and subdural convexity hygromas, consistent with reactive changes to intracranial hypotension. There were extraaxial collections along the anterolateral margins of the foramen magnum extending inferiorly, and low-lying cerebellar tonsils (fig. 2). A cervical myelogram and a computed tomographic myelogram showed an extradural leak of contrast centered on the right at the C6–C7 level. (fig. 3) There was a C6–C7 disc herniation with moderate thecal sac compression.

Ten days later, the patient underwent anterior cervical spine discectomy with autologous bone graft placement. After removing the C6–C7 disc and taking down the posterior longitudinal ligament, CSF was observed to be welling up, mostly from the right side. A blood patch with fibrin glue was constructed, and the bone graft was inserted. There was no evidence of CSF leak afterward. The patient was discharged home on the second postoperative day, free of headaches. She still experiences chronic low-grade neck pain and nonintention tremor of the right thumb. A smaller epidural mass is still present on MRI 4 months postoperatively.

Neurologic complications after CESIs are rare but devastating. Trauma may occur as a result of epidural needle disruption of nerve fibers and can be exacerbated by intraneuronal injection into the spinal cord or spinal nerve root. 5A granulomatous response may follow, with thickening of the dura, as occurred in the current patient. Dural puncture and possibly direct nerve injury from the needle likely occurred during the third block. Dural puncture would allow triamcinolone and its preservative to gain access into the subarachnoid space with resultant nerve damage. Substantial amounts of CSF leak led to intracranial hypotension and incapacitating postural headaches.

Intracranial hypotension is a relatively new diagnosis that has been increasingly recognized since 1991 with the advent of MRI. Patients present with orthostatic headache that is relieved by recumbency. 6Intracranial hypotension may occur in association with dural puncture during cervical epidural block, as in our patient, or it may occur from spontaneous CSF leak, most often at the level of the thoracic spine or cervical thoracic junction. 6Spontaneous CSF leak can be associated with trivial trauma in conjunction with weakness of the meningeal sac, meningeal diverticula, and/or spondylotic spur. 6Clinical manifestations include neck stiffness, tinnitus, ear obstruction, faintness, photophobia, nausea, and vomiting. Descent or sinking of the brain, as occurred in our patient, is due to CSF volume depletion and accounted for the low-lying cerebellar tonsils. Descent of the cerebellar tonsils may mimic type 1 Chiari malformation. Loss of CSF volume in the presence of an intact skull is compensated by intracranial and meningeal venous hyperemia.

According to the Monro-Kellie rule, there is an inverse relation of CSF volume and intracranial blood volume such that if CSF volume decreases, intracranial pressure is maintained by increased blood volume, particularly in the venous capacitance system. 7Because the pachymeninges have no blood–brain barrier, diffuse pachymeningeal gadolinium enhancement occurs. 6Other imaging abnormalities are engorgement of cerebral venous sinuses and subdural and extraarachnoid fluid collections, as shown on MRI and computed tomographic myelography in our patient at 7 months. Enlargement of the pituitary gland, decreased size of the ventricles, obliteration of prepontine or perichiasmic cisterns, flattening of the optic chiasm, crowding of the posterior fossa, and engorgement of the cervical epidural venous plexus may also occur. Traction, distortion, compression, or vascular congestion of cranial nerves may have been responsible for some of the patient’s hearing symptoms. Computed tomographic myelography is the most reliable test to demonstrate CSF leak.

Early surgical treatment was deferred in our patient despite demonstration of the anterior cervical epidural mass. This was because of the patient’s otherwise stable neurologic examination results (absence of quadriparesis/quadriplegia), increased vascularity of the mass, and anatomically difficult location of the mass. Epidural blood patch, another recommended therapy of intracranial hypotension, was not performed in the patient because of the location of the mass and presence of low-lying tonsils.

Technical aspects of cervical epidural steroid injections may affect outcomes and complications. The cervical epidural space is only a potential space that becomes diminished with pathology such as a protruding disc. 8,9In this particular case, it is likely that the needle was advanced too far into the right anterior epidural space, producing right-sided nerve root irritation and subsequent dural puncture. Measures to minimize technical complications include using the prone position, advancing the needle with constant fluoroscopic guidance in a lateral view, aiming the needle toward the site of pathology, and using a smaller-gauge (22-gauge) needle. Finally, if the patient experiences severe paresthesia or there is any indication that the dura has been punctured, the practitioner should abort the procedure to avoid injecting steroid into the subarachnoid space or nerve root. CESI should probably be avoided at the level of a large protruding disc and should be performed at another level.

In summary, we describe the case of a 39-yr-old woman who presented with a new-onset herniated disc at C6–C7. She underwent a series of three CESIs with triamcinolone over a 6-week period. Early on, she experienced headaches, night sweats, and upper neck pain. Subsequent cervical MRI revealed a gadolinium-enhancing mass occupying the anterior epidural space. Seven months after the third epidural injection, the headache become incapacitating when the patient was upright. Brain MRI revealed intracranial hypotension. A computed tomographic myelogram showed a CSF leak at C6 on the right. Anterior cervical discectomy and fibrin glue blood patch were performed, with good neurologic outcome.

The authors thank Michael Harris, M.D. (Department of Physical Medicine and Rehabilitation, MetroHealth Medical Center, Cleveland, Ohio), and Moshe Torem, M.D. (Center for Mind-Body Medicine, Akron General Health and Wellness Center, Akron, Ohio), for rehabilitative care; Matt J. Likavec, M.D. (Division of Neurosurgery, MetroHealth Medical Center), for surgical care; Boris A. Karaman, M.D. (Department of Radiology, MetroHealth Medical Center), for reviewing the radiology findings; Steve Grove, M.A., L.S. (Librarian), Terri Castro (Clerk Typist), and Sharon Malames (Library Clerk, Brittingham Library, MetroHealth Medical Center); and colleagues at MetroHealth for their support.