Low back pain (LBP), which is the most common health problem resulting in pain and disability, is present in up to 70% of adults aged 60 years old or older and its incidence increases with age [
1]. Many studies have shown that epidural steroid injection can be helpful for relief of radicular pain. Known serious complications after epidural anesthesia, such as epidural hematoma, abscesses, and arachnoiditis, are uncommon with a reported incidence of approximately 1/150,000. However, the prevalence after transforaminal epidural steroid injection (TFESI) has not been studied [
2]. We report on two patients who developed acute, severe back pain without neurological deficits after receiving TFESI due to large amounts of epidural hematoma. Fluoroscopy-guided aspiration for epidural hematoma was performed on these two patients, resulting in their back pain changing from severe to mild. Neurological defects did not progress and absorption of the hematoma was shown on magnetic resonance imaging (MRI) within two or three weeks. Physicians often decide to treat epidural hematoma through emergency surgery because patients suffer motor deficits and cauda equina syndrome. However, if large amounts of epidural hematoma are not causing neurological deficits, it can be aspirated until it is absorbed.
DISCUSSION
LBP, which is the most common health problem, causes pain and radiculopathy as a result of nerve irritation and inflammation. Many studies have shown that injecting the appropriate drugs through the epidural space can help relieve radiculopathy pain [
2]. This procedure has very rarely caused life-threatening complications, including increased neurological deterioration, intravascular injections, cerebrospinal fluid fistulas, persistent positional headaches, arachnoiditis, hydrocephalus, air embolisms, urinary retention, allergic reactions, stroke, blindness, hematomas, and seizures [
3].
The three main techniques for epidural steroid injection in the lumbar spine include transforaminal, interlaminar, and caudal approaches [
4]. TFESI is considered to be the most target-specific modality requiring the smallest volume to reach the primary site of pathology. It has been evaluated in an observational study to be a reasonable treatment of lumbar spinal stenosis and can be an alternative to surgery [
5,
6]. The traditional needle target for transforaminal injection is caudad to the inferior margin of the pedicle, which is superior, lateral, and anterior to the targeted exiting nerve. This approach, usually referred to as the safe triangle approach, can be performed with minimal risk of nerve injury, intrathecal puncture, or vascular injection. However, recently, there have been reported cases of paraplegia as a result of the safe triangle approach due to the location of the radicular or radiculomedullary artery in the anterosuperior portion of the foramen [
4]. Therefore, significant care needs to be taken even when using the safe triangle approach.
Spinal epidural hematoma (SEH) is a rare condition in which blood accumulates in the epidural space and mechanically compresses the spinal cord. If it improperly managed, it can cause permanent neurologic deficits [
7]. Although it is unknown how frequently epidural hematoma occurs as a result of epidural steroid injections, there are surprisingly few case reports of SEH after epidural steroid injections. The incidence may be comparable to the risk of epidural hematoma after epidural anesthesia, which is 1 in 150,000-190,000 [
7,
8]. The pathogenesis of SEH remains unknown. Most hematomas occur spontaneously, with no known cause. However, some spontaneous lesions are related to vascular anomalies, epidural procedures, hypertension, and physical exertion [
7]. Some researchers have suggested that SEH may have developed due to bleeding from the sudden stretching and rupturing of the spinal epidural artery. Patients who suffer arterial rupture also often suffer radicular pain and bleeding originating in the root zone. Others researchers have suggested that it is caused by epidural venous plexus which are composed of thin, valve-less vessels. Spinal epidural venous plexus is usually located at the posterior of the dural sac, so progressive motor and sensory damage often appear delayed [
9]. Kim et al. [
2] reported on a spinal epidural hematoma occurring at a distance from the transforaminal epidural injection site. They suggested the increasing pressure in the epidural space caused the hematoma rather than direct needle injury. Even simple actions, such as coughing and defecations, increases pressure in the epidural space, so epidural steroid injections can cause large increases in the epidural space pressure, especially in elderly patients with spinal stenosis.
A meta-analysis showed that anticoagulation is the second-most common underlying etiology for spontaneous hematoma formation, following idiopathic occurrences with no identifiable cause [
8]. Also, spinal and epidural procedures in combination with anticoagulation were the fifth-most common cause of epidural hematoma. Additional risk factors are age, anatomic abnormalities of the spinal cord and vertebral column, needle size, traumatic needle or catheter placement, epidural techniques being used instead of spinal techniques, indwelling epidural catheters during low molecular weight heparin administration [
7,
8] and increasing pressure in the epidural space [
2]. In the cases in this report, epidural hematomas developed despite adequate discontinuation of anticoagulants in both patients. Physicians performing TFESI should always remember that there are many other factors besides anticoagulants that can cause complications.
Prompt evacuation of the hematoma is generally regarded as the first treatment option for symptomatic spinal epidural hematoma [
10]. Decompressive laminectomy is the most common and recommended procedure for removal of spinal epidural hematoma. Epidural hematomas with neurological symptoms are most frequently treated with decompressive laminectomy. There are only a few reported cases of treating them with non-surgical epidural aspiration [
2,
11-
13]. In the absence of neurological deficits, nonsurgical management of epidural hematoma in hemophilia teenagers have also been reported [
14]. Surgical treatment of epidural hematoma is pursued depending on whether neurological deficits have occurred. Therefore, it is necessary to closely monitor the occurrence of neurological symptoms. We presented two cases of large amounts of hematoma causing severe back pain that responded to nonsurgical management. In our cases, although there was a large amount of epidural hematoma, there were no neurological symptoms. Neurosurgery was prepared for, but the hematoma was treated by epidural hematoma aspiration.
These reports are believed to be the first of treating epidural hematoma occurring after transforaminal epidural steroid injection through non-surgical hematoma aspiration. If large amounts of epidural hematoma do not show neurological deficits, epidural hematoma aspiration can be considered until the hematoma is absorbed.