Spinal Epidural Hematoma Related to Vertebral Fracture in an Atypical Rigid Diffuse Idiopathic Skeletal Hyperostosis

Introduction

Spinal epidural hematoma (SEH) is a rare condition that causes spinal cord compression and neurological deficit, being spontaneous and associated with minor trauma, concurrent bleeding disorders, and anticoagulant medications, in most cases. Posttraumatic SEH is less common than spontaneous lesions, and its incidence has been estimated to be less than 1% to 1.7% of all spinal injuries. It is rarely associated with spine fracture, with an incidence from 0.5% to 7.5%. ¹ However, in patients with ankylosing spinal disorders (ASDs), such as ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH), the risk increases by 7.6-fold. ² In addition, DISH and AS share important clinical features, such as functional spinal ankylosis, poor bone quality, advanced patient age, and an equivalent risk of epidural hematoma. ^3-4 Furthermore, DISH criteria have been previously described according to Resnick and Niwayama. ⁵ However, the presence of degenerative changes and intra-articular bone fusion would exclude DISH diagnosis. The purpose of this report is to describe the management of an epidural hematoma related to hyperextension vertebral fracture and neurological impairment in a patient with ASD rigid atypical DISH-like spine.

Case Report

A 79-year-old female presented to the emergency department with a 5-hour history of low back pain after a 1 m fall and without any other symptoms. During the initial physical examination, she reported dysesthesias, mild weakness in both lower limbs, and radicular symptoms on both sides. She did not mention any previous spinal disorders or spine surgery. She had a history of stroke 10 years before without sequelae receiving acetylsalicylic acid (100 mg/day). During the second examination, 2 hours after the initial one, she had thoracic and lumbar pain and sphincter disturbance. There was an absence of lower limb motor function, and sensitivity was preserved.

Initial X-ray images did not reveal spinal injury. Computed tomography (CT) showed transverse disruption of the anterior column at the T4 vertebral body, which extends up to the posterior bloc at the T3-T4 level, indicating a hyperextension injury pattern (Figure 1), and fusion facets bloc at T3-T4 and T4-T5 bilateral levels were observed. Sagittal T1- and T2-weighted magnetic resonance (MR) studies revealed posterior soft tissue edema and increased signal in the T4 vertebral body, compatible with a fracture and a 12-cm-long posterior epidural mass from C7-L1 levels of the posterolateral aspect of the spinal cord, consistent with epidural hematoma, which displaced the spinal cord in the canal space (Figure 2). The lesion was homogeneously isointense relative to the spinal cord on T1-weighted sequences, and it was plainly and homogeneously hyperintense on T2-weighted sequences. Then, it was classified as a B3 hyperextension fracture type with spinal cord compromise according to the American Spinal Injury Association (B Grade). According to the most recent AOSpine Thoracolumbar Injury Classification System based on vertebral injuries, morphologic pattern, neurologic status, and modifiers, the lesion was classified as T3-T4 B3, T4 A1; N3; and M2. ⁶

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Figure 1.

Preoperative computed tomography (CT). Sagittal images showing transverse disruption of the anterior column at the T4 vertebral body, which extends up to the posterior bloc at the T3-T4 level. The finding suggests a B3-hyperextension fracture, the most common pattern found in patients with rigid spine (T3-T4 B3, T4 A1, AOSpine Thoracolumbar Injury Classification System). Facet bloc joint T3-T4 and T4-T5 at the injury level are noted (white arrow).

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Figure 2.

Magnetic resonance (MR) sequences show the most frequent pattern of spinal epidural hematoma (SEH). Isointense on T1-weighted and hyperintense on T2-weighted images. Axial images exhibit spinal cord compression. The short tau inversion recovery (STIR) sequence shows edema of the posterior ligamentous complex.

The patient was treated with high-dose methylprednisolone succinate according to National Acute Spinal Cord Injury Study 2 trial. ⁷ Due to the progressive neurologic symptoms, a surgical procedure was carried out. A T4-T7 left decompressive partial laminectomy by midline posterior approach was performed to expose the spinal canal. During surgery, an organized hematoma compressing the spinal cord was found and drained. Above T4 and below T7 levels, the hematoma was thinner and did not deform the spinal cord, being possible to remove it by wash and drain. The integrity of interspinous ligaments and contralateral facets joints was kept to prevent the increase of instability. The unstable nature of the fracture required a T3-T9 instrumented fusion, which was performed using thoracic pedicle screws, adding a surgical field bone graft. An intraoperative hemostatic thrombin matrix was used to prevent rebleeding.

Motor function improved in the immediate postoperative hours and the unreactive neurogenic bladder and fecal incontinence disappeared. Four days after surgery, the patient began to receive physical therapy. The lumbar pain, radicular symptoms, and neurological deficit completely disappeared 1 year after surgical treatment. Currently (after 2.5 years of follow-up), the patient has no neurological deficit. She is able to walk without any help, and at the most recent examination visit, she presented occasional low back pain (Figure 3).

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Figure 3.

Postoperative images. X-ray after 1-year follow-up.

Discussion

The management of elderly patients with vertebral fracture and rigid spine is challenging primarily due to the inherent instability of a typical hyperextension fracture. Occasionally, a neurological lesion may be also present hours or days after the injury, ⁸ and the appearance of an epidural hematoma should then be suspected. In these patients, the presence of medical comorbidities is common, and as a result, they often follow an antiplatelet therapy. In these cases, an urgent or early treatment must be considered.

Diagnosis using conventional radiology images may be difficult due to altered normal bony landmarks, secondary to preexisting pathologic osseous and soft tissues changes in patients with ASD (osteoporosis, joint capsules, and ligamentous ossification). ³ Computed tomography scans may be helpful in showing occult fractures, typically located at the low cervical spine and throughout the vertebral body or disc space being the most common pattern type B hyperextension fracture. ^2,4 The MR studies are very sensitive in identifying soft tissue injuries, the presence of edema in normal marrow elements as a reliable sign of fracture, and SEH. In the latter, the most common pattern is the homogeneous isointense on a T1-weighted and hyperintense on T2-weighted images. ⁹ Resnick and Niwayama ⁵ have described 3 defining criteria for DISH—namely, the relative preservation of disc height in the evolved areas and the absence of extensive radiographic changes of degenerative disc disease (intervertebral osteochondrosis), including vacuum phenomena and vertebral body marginal sclerosis; the presence of calcification and ossification along the ventrolateral aspects of at least 4 contiguous vertebral bodies with or without localized pointed excrescences at intervening vertebral body–disc junctions; and the absence of apophyseal joint bony ankylosis and sacroiliac joint erosion, sclerosis, or intra-articular bony fusion. In this case report, degenerative changes such as vacuum sign disc, osteophytes, and flowing discontinuous ossification in the lumbar and thoracic spine were observed. Uncommonly, bloc facets joints at T3-T4 and T4-T5 levels were found. These findings would be more compatible with a degenerative condition than with a congenital or inflammatory origin. These 3 findings would contradict the criteria described by Resnick and Niwayama ⁵ above. Therefore, and despite the patient requiring similar management, in terms of diagnosis, the case presented here defines an atypical case of DISH.

The management and treatment in elderly patients suffering from a rigid spine with a vertebral fracture associated with an SEH and neurologic impairment remain a challenge. First, conservative treatment is associated with high mortality and is indicated in palliative care patients or for those who are not candidates for surgical intervention due to poor hemodynamic status or in cases of refusal of surgery. Second, medical therapy with methylprednisolone is also used in patients with spinal cord injury to minimize secondary spinal damage. However, methylprednisolone use can cause complications that may outweigh the potential benefits. ^10,11 Oxygen therapy and maintenance of the systolic blood pressure >100 mm Hg are treatments that have shown some evidence of an adequate spinal cord perfusion maintenance. ¹²

In the absence of an effective medical therapy, an early decompression can have a neuroprotective effect to improve neurological status. ¹³ Several studies have revealed that the presence of hemorrhage and increased hematoma length are associated with decreased motor recovery. Surgical decompression has the potential to reduce intradural pressure, thus increasing blood flow to the spinal cord, reducing ischemia, and preventing secondary injury mechanisms. Also, animal studies have shown the relation between neurologic recovery and early decompression. ¹⁴

Less aggressive techniques than standard decompressed surgery, such as endoscopic evacuation, percutaneous drainage guided by CT or guided ultrasound epidural hematoma drainage, and lumbar puncture can be performed if isolated epidural hematoma is present. ¹⁵ However, when epidural hematoma is associated with an unstable hyperextension vertebral fracture, then decompression and fusion are required. ⁴

In this case report, decompression was performed at the most heavily compressed area by partial unilateral, instead of bilateral, laminectomy at T4-T7 levels, which was sufficient to decompress the spinal cord. The upper and lower levels of the hematoma were thinner, did not deform the dural sac, and were removed by wash and drain. Moreover, the integrity of interspinous ligaments and contralateral facets joints was kept, thus preventing the increase in instability.

Due to spinal rigidity and the high instability of these fractures caused by long lever arms, long posterior instrumentation and fusion are generally required. Levels of fusion vary depending on the level of lesion (ending in thoracic apex and transitional areas must be avoided). Caron et al., suggest 3 fusion levels above and below the fracture in order to prevent failure. ⁴ In addition, rigid spine in elderly patients is generally associated with osteoporosis and often requires augmentation techniques or hooks ¹⁶ at the upper levels to prevent proximal failure and fenestrated screws with polymethyl methacrylate (PMMA) to prevent pullout. ¹⁷ However, in this case, due to the presence of a rigid bloc at T3-T5 levels, the integrity of posterior ligament complex, and an unaffected facet joint at the upper levels, only 1 level above the lesion was carried out. Moreover, bone quality was found adequate and construction was performed requiring only the use of pedicle screws.

Complications may arise after surgical intervention, including wound infection, lung problems, urinary tract infections, thrombotic events, and the need of tracheostomy and gastrostomy. Prognosis will be determined by age, gender, hematoma size, and progression of symptoms. A delay in diagnosis and treatment results in neurological complications of up to 80%. Mortality in patients with SEH and spine fractures is correlated with advanced age, the number of comorbidities, and a low-energy mechanism of injury. ^15,18

Epidural hematoma and vertebral fracture are unusual conditions. The elderly patients with rigid spine, who suffer from low-energy injuries, should be considered to have a hyperextension fracture, and CT scans and MR images should be reviewed carefully to rule out any occult fracture and SEH. If neurological impairment is present, urgent or early surgical hematoma drainage and instrumented fusion must be performed to achieve stability and functional recovery. The same management procedures as in a typical case of DISH have been applied effectively to treat the case presented here with an atypical rigid spine.