SECTION III: REGULAR AND SPECIAL FEATURES: Orthopaedic • Radiology • Pathology Conference
HISTORY AND PHYSICAL EXAMINATION
A 71-year-old woman was referred to a spinal unit with severe back pain. The symptoms had become progressively disabling during the previous 6 months. This was associated with bilateral leg pain. She was confined to a wheelchair for 1 month. The patient also gave a history of a fall from a height of 3 feet 1 year previously, for which she did not seek any medical attention. The pain had settled with analgesics within 1 week. Otherwise the patient did not have a significant medical or surgical history.
On physical examination, she had right-sided quadriceps weakness (Medical Research Council Grade 3/5). A right-sided kyphoscoliotic deformity of the lumbar spine also was observed.
Laboratory tests showed a leukocyte count of 8.5/μL (normal, 4–11/μL), erythrocyte sedimentation rate of 35 mm per hour (normal, 1–35mm/hour), C-reactive protein of 10 mg/L (normal, 1–10 mg/L), normal serum electrophoresis, and normal bone and liver profiles. Plain radiographs were obtained (Figs 1, 2), the results of which prompted MRI scans and a bone scan to be obtained. Several representative cuts of these are shown in Figures 3–6. Based on history, physical findings, and imaging studies, what is the differential diagnosis?
The plain AP radiograph (Fig 1) of the lumbar spine shows collapse of the L3 vertebra with an indistinct right pedicle and a left convex scoliosis. The lateral radiograph (Fig 2) shows anterior wedging of L3 vertebral body with mild retropulsion of the posterior vertebral margin. The adjacent vertebral bodies are of normal density and contour.
The coronal T2-weighted MRI scan (Fig 3) shows a cleft in the body of L3 with a horizontal intravertebral line (black arrow) of increased signal.
The sagittal T1-weighted MRI scan (Fig 4) shows marked compression of the L3 vertebral body. The lesion is localized to one level. There is no evidence of a destructive soft tissue mass within the canal or paravertebral soft tissues. The pedicles and posterior elements are not involved.
The axial T1-weighted section through the L3 vertebral body (Fig 5) shows low signal marrow anteriorly attributable to the vertebral collapse, but good preservation of adjacent fat planes (white arrows) between the vertebra and the psoas muscles. There is retropulsion of the posterior vertebral margin.
A bone scan taken preoperative (Fig 6) shows isolated increased uptake at the L3 level. No other focal abnormalities are seen.
- Secondary tumor
- Osteoporotic collapse
- Kummell’s disease
An image-guided biopsy was done. The histologic findings are shown in Figures 7 and 8.
Based on the history, physical findings, radiographic studies, and histologic picture, what is the diagnosis and how should this patient be treated?
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Microscopically, there is necrosis of the marrow fat and associated hematopoietic tissue (black arrow). In addition, the necrotic bony trabeculae (white arrow) show absence of viable osteocytes within the lacunae. There are no signs of neoplasia or infection. This appearance is suggestive of primary osteonecrosis of the vertebral body.
Kummell’s disease (delayed posttraumatic osteonecrosis of the vertebral body)
DISCUSSION AND TREATMENT
We planned an anterior corporectomy of the L3 vertebral body and stabilization. However, because of the poor general condition of the patient, posterior spinal instrumentation (Figs 8, 9) and a biopsy of the vertebral body were done. Aerobic, anaerobic, acid fast bacilli, and fungal cultures showed no growth. The patient made a remarkable recovery and started mobilizing independently within 1 week of surgery with steady resolution of the neurologic deficit. She remains pain-free at 12 months after surgery.
In this case, the patient presented with severe back pain, difficulty in mobilizing, and a neurologic deficit. These symptoms, and the radiographic evidence of vertebral collapse in a 71-year-old patient made it imperative to consider possible malignancy. A careful clinical search for any possible primary proved negative. The bone scan revealed that the lesion was localized to one vertebra. The normal bone profile and serum electrophoresis and the histologic picture helped to rule out a neoplastic disorder. We also considered osteoporosis and infection as other possible diagnoses. The inflammatory markers were within normal limits and the MRI scan did not suggest an infective disease. Osteoporotic collapse usually is not associated with neurologic deficit and frequently involves multiple levels. Magnetic resonance imaging may help in differentiating this from other causes of vertebral collapse. Kummell’s disease is a rare spinal disorder characterized by avascular necrosis of a vertebral body occurring in a delayed fashion after minor trauma. As reported by Young et al,10 in 1895, the German surgeon Hermann Kummell (1852–1937) described a series of six patients who had vertebral collapse after minor trauma. Three phases have been described.5,6,10 In the first phase, after minor trauma, patients initially experience back pain that subsides spontaneously. In the second phase, which is weeks to months after an accident, there is a recurrence of back pain. In the third phase, patients have kyphotic spinal deformities, which develop without any additional injury. Kummell’s original observations were made before radiographs were discovered. When radiographs became routinely available, the concept that initial radiographs were normal in patients with Kummell’s disease was added.8,9
Kummell’s disease occurs typically in middle-aged and elderly patients with a slight male predominance. The most common injury leading to this is a fall. Acute back pain then develops in the lower thoracic and upper lumbar region. During the initial phase, there are no neurologic signs. When the pain recurs, the most obvious abnormality is a kyphotic deformity corresponding to the collapsed vertebra. In later stages, the patients can have overt neurologic deficits develop, depending on the site of collapse. Usually only one vertebra from T8 to L4 is involved.
The pathophysiology of Kummell’s disease is poorly understood. Chronic steroid use and osteoporosis are thought to be predisposing factors.2,10 Kummell thought that this condition results secondary to disruption of the nutritional supply to the vertebral body.10 Some authors have suggested that the anterior ⅓ of vertebral body is a watershed zone because of the characteristic blood supply of this area.2,10 Disruption of this watershed zone arterial supply results in a condition similar to avascular necrosis occurring in other parts of the body. The presence of necrotic bone on histopathologic evaluation in the absence of any other significant disorders is highly suggestive of this condition.
Radiographs often are not helpful in differentiating between osteoporotic collapse and avascular necrosis. However, intravertebral vacuum phenomenon, if present, is highly suggestive of Kummell’s disease.3,5,7,10 The other striking feature in collapse secondary to avascular necrosis is a marked linear, horizontal area of hyperintensity on the T2-weighted images. A peripheral zone of diminished signal surrounding the central area of hyperintensity on the T2-weighted images termed the “double line sign” also is found.2,5 This same pattern has been reported in cases of avascular necrosis of the femoral head.4 Baur et al1 reported that identification of this pattern is important in distinguishing malignant from nonmalignant forms of vertebral compression fractures.
Because of the rarity of the condition and the paucity of literature, experience in treatment is limited. Different factors that should be taken into account before treatment include the severity of pain, deformity, and neurologic deficits. Earlier reported results favored nonoperative treatment including bed rest and orthotics. Young et al support surgical treatment including spinal instrumentation, corporectomy, and interposition bone grafting.10 Surgical treatment has a definite advantage because the diagnosis can be confirmed. This also helps in better correction of the deformity and early mobilization of the patient.
Even though Kummell’s disease is uncommon, orthopaedic surgeons should be aware of the condition and should consider the diagnosis in patients with recurrent pain after an asymptomatic period after minor trauma to the spine.
See page 297 for diagnosis and treatment.
1. Baur A, Stabler A, Arbogast S, et al: Acute osteoporotic and neoplastic vertebral compression fractures: Fluid sign at MR imaging. Radiology 225:730–735, 2002.
2. Chou LH, Knight RQ: Idiopathic avascular necrosis of a vertebral body: Case report and literature review. Spine 22:1928–1932, 1997.
3. Maldague BE, Noel HM, Malghem JJ: The intravertebral vacuum cleft: A sign of ischemic vertebral collapse. Radiology 129:23–29, 1978.
4. Mitchell DG, Rao VM, Dalinka MK, et al: Femoral head avascular necrosis: Correlation of MR imaging, radiographic staging, radionuclide imaging and clinical findings. Radiology 162:709–715, 1987.
5. Naul LG, Peet GJ, Maupin WB: Avascular necrosis of the vertebral body: MR imaging. Radiology 172:219–222, 1989.
6. Nicholas JJ, Benedek TG, Reece GJ: Delayed traumatic vertebral body compression fracture: Part I: Clinical features. Semin Arthritis Rheum 10:264–270, 1981.
7. Resnick D, Niwayama G, Guerra Jr J, Vint V, Usselman J: Spinal vacuum phenomena: Anatomical study and review. Radiology 139:341–348, 1981.
8. Rigler L: Kummel’s disease with report of a roentgenographically proved case AJR 35:749-753, 1935.
9. Steel H: Kummell’s disease. Am J Surg 81:161–167, 1951.
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10. Young WF, Brown D, Kendler A, Clements D: Delayed post-traumatic osteonecrosis of a vertebral body (Kummell’s disease). Acta Orthop Belg 68:13–18, 2002.