Lumbar spine neuroarthropathy (Charcot joint) caused by a myxopapillary ependymoma

Abstract

A 57-year old highly functional paraplegic man status post T10–S1 laminectomy and tumor resection followed by cobalt irradiation of a myxopapillary ependymoma 47 years previously, presented with increasing lumbar pain when upright and when transitioning from his wheelchair. Pain improved when supine. Lower extremity pain and spasms/spasticity were treated 30 years previously with a L3 and L4 rhizotomy/nerve transection. Continence required bladder selfcatheterization and maintenance of a colostomy. Examination was notable for flaccid paraplegia (longstanding and unchanged), a T10 segmental sensory level (also longstanding) and lumbar kyphosis. Current MRI (Fig. 1) revealed a pseudoarthrosis at the L2–3 disc interspace (1). Charcot joints may be seen in patients with loss of sensation (deafferentation) affecting a limb or trunk and are most often a complication of diabetes, syringomyelia or spinal cord trauma (2). Charcot arthropathies are however rare in spine. Spinal neuroarthropathies are induced by abnormal motion between vertebral bodies that lead to articular fracture and joint disruption together with disc degeneration and endplate fragmentation. These processes eventually lead to joint widening and subluxation that may be very deforming. The predominant changes may be atrophic, as in this case, with endplate and vertebral body resorption or, more commonly, there may be hypertrophic changes characterized by osteophyte formation, bony sclerosis and formation of a paraspinal mass of mixed bone formation and fragmentation [1]. The radiographic differential diagnosis includes pathologic vertebral fracture from primary or metastatic tumor or from osteomyelitis. These entities may be distinguishable most reliably on MRI with identification of an enhancing tumor mass or abnormal inflammatory infiltration of the disc space and paravertebral tissues with high T2 signal along with enhancement of the inflammatory tissue with or without abscess formation. In comparison, Charcot spine shows endplate and facet disruption, subluxation, bone fragmentation, intradiscal vacuum phenomena or intradiscal fluid collection [2]. Limited long-term outcome data on the surgical treatment of spinal Charcot joints is available. Nonetheless, the principles of surgical intervention focus on the immobilization of the unstable pseudoarthrosis. Strategies include circumferential debridement and stabilization across the pseudoarthrosis, use of a 4-rod construct to provide greater rigidity and improved biomechanical stress distribution, extension of constructs to the pelvis, and adjunctive use of bone-morphogenic protein [3]. M. C. Chamberlain (&) Department of Neurology, Seattle Cancer Care Alliance, Fred Hutchison Cancer Research Center, University of Washington, 825 Eastlake Ave East, MS G4940, Box 19023, Seattle, WA 98109, USA e-mail: chambemc@u.washington.edu; chambemc@uw.edu