Although fluoroscopic-guided cervical epidural steroid injections (CESIs) are widely used for the management of cervical radiculopathy, it is important to assess the potential complications associated with this procedure. Intradural extramedullary (IDEM) hematomas are extremely rare, but can be a serious complication of CESIs. Reported symptoms of IDEM hematomas in the cervical spine are neck soreness/pain or radiating discomfort with subsequent motor, sensory, and autonomic dysfunction [1]. Since the consequences of IDEM hematoma after CESI can be potentially catastrophic, early recognition and surgical decompression is important. We report the case of a 71-year-old male who developed an IDEM hematoma after an attempted cervical epidural injection. This case report was approved by the Institutional Review Board of Samsung Medical Center (Approval No. SMC 2022-11-074).

A 71-year-old male visited the pain clinic with numbness and pain from the neck to the right arm and was diagnosed with cervical radiculopathy. Magnetic resonance imaging (MRI) revealed bilateral foraminal stenosis at the C3-7 level with disc degeneration, especially in C5-6 level (Fig. 1). The patient had a medical history of hypertension, but did not take any anticoagulant, antiplatelet agents, nor health supplement dugs. His physical examination and laboratory test findings including platelet count, prothrombin time (PT), and activated partial thromboplastin time (aPTT) were within the normal range. We planned to perform CESI in the C6/7 interlaminar space. We used 20G epidural needle (TUOHY, TaeChang Industry co., Ltd, Korea) as in other patients receiving CESI. When the needle tip reached the epidural space using the loss of resistance technique, we checked that no blood or cerebrospinal fluid aspirated from the needle. Then, we administered a contrast agent to confirm proper needle position and intravascular injection via fluoroscopy (Fig. 2). At that time, the patient experienced transient numbness in the right leg and the procedure was stopped immediately, resulting in incomplete contrast medium injection. The numbness soon resolved, and the patient was discharged without any neurologic complications on the day of the procedure.

Figure 1. Cervical spine MRI showing degenerative changes including bilateral foraminal stenosis, especially in C5-6 level. (A) Sagittal T2-weighted. (B) Axial T2-weighted images.

Figure 2. Fluoroscopic images of C-arm during attempt of cervical epidural steroid injection in the C6/7 interlaminar space. (A) Lateral view. (B) AP view.

Two weeks later, the patient presented to the emergency room complaining of a severe headache with a numerical rating scale (NRS; 0 = no pain, 10 = worst pain imaginable) score of 8 out of 10. He stated that he developed a mild headache and neck stiffness after the procedure that was getting worse. During two weeks, the patient denied of receiving acupuncture or chiropractic manipulation. Neurologic examination, including the cranial nerves, was normal. Hematologic investigation and the coagulation profile were all within the reference ranges except for white blood cell count, which showed a slightly elevated result of 12.13 x 103/μL (reference range: 3.8-10.58 x 103/μL). The patient was tentatively diagnosed with a traumatic intracranial hypotension headache due to the postural headache and history of epidural injection. Computed tomography (CT) angiography and brain MRI with diffusion imaging were performed to rule out cerebral aneurysm, infarction or meningitis. However, spinal MRI revealed an IDEM hematoma at the C7-T1 level (Fig. 3) with intraventricular hematoma (IVH) (Fig. 4) and subarachnoid hemorrhage (SAH) in the sacral region. Cerebrospinal fluid analysis revealed 627,000 red blood cells/mm3 and 797 white blood cells/mm3, indicating SAH. Since the patient did not exhibit neurologic deficits, he was admitted to the general ward for close observation. Epidural blood patch (EBP) was not administered because of the underlying SAH and IDEM hematoma. Instead, the patient underwent conservative management with acetaminophen, ketorolac, and pethidine. However, a week later, his right upper extremity exhibited grade 2 motor weakness. Follow-up spinal MRI revealed an increase in the size of the IDEM hematoma, extending from the C6 to T4 level with cord compression and myelopathy at C5-7 (Fig. 5). The patient was referred to the neurosurgical team and emergent surgical evacuation of the hematoma was performed. During the two-month follow-up period after surgery, the patient regained full muscle power except for his right finger abductor (right/left = 3–/5).

Figure 3. Cervical spine MRI showing intradural extramedullary hematoma (white arrow) at C7-T1 level. Axial image is at the level of C7 upper body marked as white line in the sagittal view. (A) Sagittal T1-weighted. (B) Axial T1-weighted images. (C) Sagittal T2-weighted. (D) Axial T2-weighted images.

Figure 4. Brain MRI showing intraventricular hemorrhage. Axial view.

Figure 5. Cervical spine MRI showing intradural extramedullary hematoma (white arrow) at C6-T4 level with cord compression and myelopathy at C5-7. Axial image is at the level of C7 upper body marked as white line in the sagittal view. (A) Sagittal T1-weighted. (B) Axial T1-weighted images. (C) Sagittal T2-weighted. (D) Axial T2-weighted images.

The term IDEM spinal hematoma refers to either subdural, subarachnoid, or both hematomas occurring in the spine [2]. Although very rare, reported causes of IDEM hematomas include trauma, iatrogenic injury (epidural catheter or lumbar puncture), bleeding derived from anticoagulant medication, an underlying neoplasm, arteriovenous malformation, and acupuncture [3,4]. In our case, after an attempted CESI, the patient developed a headache progressing to motor weakness as the size of the hematoma increased.

There have been several case reports of epidural hematomas after ESI. However, IDEM hematomas after such procedures are seldomly observed. This is because the epidural space contains major blood vessels, whereas the IDEM space does not contain major blood vessels or bridging veins. Instead, the vasculature involves only a delicate network of vessels along the lateral margins of the dura [5]. In addition, the less defined anatomical space of the spine makes it difficult to distinguish among subdural, subarachnoid, and mixed bleeding patterns [2].

Common initial symptoms of cervical IDEM hematomas are neck soreness/pain with subsequent motor, sensory, and autonomic dysfunction. Among the elderly, neck soreness is a common symptom [1]. The patient in our case also developed a headache including neck discomfort that lasted two weeks after the procedure, followed by motor weakness. However, the symptoms of IDEM hematomas may be nonspecific, for example, only a headache is present without any neurologic deficits or any relevant history, leading to delayed or misdiagnosis. Therefore, meticulous history taking, physical examination, laboratory tests, and imaging work-ups should be performed to differentiate from other cerebral or cervical lesions such as cerebral infarctions, aneurysms, or subarachnoid hemorrhages [1].

In our case, when the patient first presented to the emergency room, their history and clinical presentation led us to an initial diagnosis of intracranial hypotension. Since the patient had a history of cervical epidural injection, EBP was initially considered for symptom control. However, there are several reports of iatrogenic epidural hematomas after EBP resulting in spinal cord and/or nerve root compression [6]. We concluded that our patient would be at higher risk of cord compression after EBP in that he already had an IDEM hematoma near the EBP target. Therefore, we did not administer EBP.

The timeframe from the onset of hemorrhage to the clinical presentation varies. IDEM hematomas can be subcategorized into traumatic and non-traumatic types. In the case of traumatic types, symptoms of an IDEM hematoma often appear immediately after the traumatic event. Comparing with previously reported cases with IDEM hematomas, our case is unique since the patient initially presented to the emergency room two weeks after an attempted cervical epidural injection. The symptoms appeared later than other reported cases and were vague without neurologic deficits. This slow progression may have been due to the lack of anticoagulation therapy or bleeding diathesis.

MRI is the best imaging modality for diagnosing spinal IDEM hematomas as it is capable of visualizing spinal hematomas as well as other spinal cord pathologies [7]. On MRI, IDEM hematomas appear as space-occupying lesions within the dura mater, exhibiting a semicircular or curvilinear shape, and with different signals depending on the age of the hematoma [3,8,9]. Typically, acute hematomas appear isointense to slightly hyperintense compared with the spinal cord on T1-weighted images, and have mixed or heterogeneous signal intensity on T2-weighted images [10].

Reported risk factors of spinal hematomas after neuraxial blocks include older patient age, the use of anticoagulation medication, anatomic abnormalities of the spinal cord and vertebral column, difficult or repeated spinal punctures, complicated blocks such as “bloody taps”, the use of larger needle sizes, and indwelling epidural catheters [9,11,12]. Our patient had the risk factor of being elderly and having disc degeneration and foraminal stenosis at the C5-6 level. In one case report of a 75-year-old male who developed an IDEM hematoma, the patient had a history of receiving chiropractic manipulation prior to admission. The authors suggested degenerative changes of the cervical spine such as an abnormal curvature, fragile musculature, and spur formation in the elderly as risk factors for hematomas from trauma [1]. Unfortunately, degenerative diseases of the spine are age-related changes that are common in elderly people with this population often taking anticoagulant medications [13,14]. Therefore, especially in the elderly, physicians should strictly follow anticoagulation guidelines and avoid traumatic needle placement.

The treatment strategies for IDEM hematomas vary depending on patient symptoms. If only minimal neurologic deficits are present, conservative management may be reasonable [7]. However, if significant neurologic deficits are present, surgical decompression is necessary. In this situation, the timing of surgery, anatomic location of the hematoma, and initial severity of the preoperative symptoms are known to influence the patient’s functional outcome [8]. Since the consequence of an IDEM hematoma after ESI is potentially catastrophic, prompt recognition and treatment could improve the outcome.

Well-documented causes of IDEM hematomas include spinal cord abscesses, vascular malformations, bleeding derived from the use of anticoagulant medication, tumor invasion, and trauma. As in the present case, iatrogenic trauma from epidural injections can lead to hematoma deposition, especially in the elderly with severe degenerative changes. Although the incidence of IDEM hematomas is low, we believe that the continued reporting of such complications is vital to improve prognoses through early recognition and treatment.

No potential conflict of interest relevant to this article was reported.

Poster presentation at the 73st annual meeting of the Korean Pain Society, Pain Medicine 2022. May 21-22, 2022. Live Web Seminar.