A synovial cyst in the cervical spine causing acute spinal cord compression

Abstract

Abstract-The increased postural sway of patients with disorders of the vestibular system improves with vision. The suppression of pathologic nystagmus also reduces sway. Because the latter effect cannot be attributed to retinal slip as a relevant feedback for postural control, the authors investigated how eye movements rather than retinal slip affect balance. They found that slow eye movements increase sway, possibly by an efference copy, which explains why spontaneous nystagmus causes postural imbalance. NEUROLOGY 2005;65:1291-1293 S. Glasauer, PhD; E. Schneider, PhD; K. Jahn, MD; M. Strupp, MD; and T. Brandt, MD Balance control depends on the integrity of various sensory and motor systems. Increased body sway is found in patients with vestibular, proprioceptive, and cerebellar disorders. However, if visual input is sufficient, the postural stability of most patients is restored to normal levels. This can easily be demonstrated in healthy subjects by having them close their eyes while assuming an unstable posture, e.g., with feet in the heel-to-toe position.What is the visual cue for postural stabilization? Comparing posture in darkness and posture with vision of stable space-fixed targets or with full-field vision revealed a significant increase in stability with vision.1 Large-field moving visual scenes were found to cause body sway in the same direction as stimulus motion.2 Only a few studies 3-5 have tried to determine which visually derived signal may be used for the motor control of body sway. On the basis of the available experimental data, it is commonly believed that retinal slip, i.e., target or background motion on the retina, is the afferent signal that determines visually evoked postural responses. However, during fixation of a space-fixed target, retinal slip is minimized by the vestibulo-ocular reflex and visual smooth pursuit. Therefore, eye movement rather than retinal slip reflects head motion in space. Is it conceivable that eye movement signals, efferent or reafferent, are used for the motor control of postural sway? Here we provide evidence that slow eye movements in the absence of substantial retinal slip can significantly affect postural stability.Methods. Healthy subjects (six women, nine men; aged 22 to 45 years) standing heel-to-toe on a force-measuring platform (Kistler 9284) were asked to fixate a target spot on a translucent screen 0.7 m in front of them (lateral field of view 94°). Eye and head movements were monitored by video-oculography (lateral field of view of goggles 74°) and head position tracking (Intersense IS-600). After giving their informed consent, the subjects were asked to stand as stable as possible during nine randomized conditions. Fixation conditions included the following: standing in complete darkness and looking straight ahead (F1); fixation of a stationary target in darkness (F2) and fixation of a stationary target on a moving background (F3). Eye movement conditions were as follows: pursuing a moving target in darkness (E1); pursuing a moving target on a sta...

Synovial cysts of the cervicothoracic junction causing myelopathy: report of 3 cases and review of the literature

“…The first report of a synovial cyst in the cervical spine was in 1974 by Kao et al 33 The cause of synovial cysts is not yet clearly identified, but they have been related to degenerative spinal facet disease, 42 rheumatoid arthritis, 15 postoperative segmental spinal instability, 30 trauma, spondylolisthesis, and abnormal joint movement. 10,13,41 In our cases, only one cyst related to trauma, and plain radiographs and CT demonstrated degenerative changes in all 3 patients. These degenerative changes can also be age-related, but the mean age of our patients (55.3 years) is younger than that of the typical patient with synovial cysts described in the literature, who is described as being in his or her mid-60s.…”

Synovial cysts of the spine: long-term follow-up after surgical treatment of 141 cases in a single-center series and comprehensive literature review of 2900 degenerative spinal cysts

“…The longest symptom duration reported in the literature is 10 years, but some authors reported acute onset of symptoms within days or even 1 day. 17,26,35,50,62,90,91,98,99 Acute hemorrhage into the cyst is believed by many authors to lead to this acute or aggravated symptomatic compression of neural structures, because hemorrhage has been found in many cysts with short symptom duration. 19,29,35,38,48,71,77 However, intracystic hemorrhage is not necessarily correlated with acute onset of symptoms.…”

The role of spinal fusion in the treatment of cervical synovial cysts: a series of 17 cases and meta-analysis

“…These findings, combined with the fact that synovial cysts are typically a disease of the elderly and oftentimes seen at the cervicothoracic junction, point to underlying spinal instability as a culprit. 15,41 While surgical outcomes in cases of antlantoaxial and subaxial cysts were similar in the current meta-analysis, these lesions differ in their typical presenting symptoms and treatments. 37 Patients with atlantoaxial cysts more often present with myelopathy, whereas those with subaxial cysts may present with myelopathy and/or radiculopathy.…”

“…38 The etiology and pathogenesis of cervical synovial cysts (CSCs) is poorly understood, and it is hypothesized that these cysts develop in the degenerated and segmentally unstable spine. 15,41 Spinal degeneration is thought to cause synovial membrane protrusion through small joint capsule defects, forming a para-articular cavity. 5 Furthermore, current evidence suggests that the mechanical stress on the spine induces an inflammatory cascade (upregulation and release of interleukin-1, interleukin-6, platelet-derived growth factor, and vascular endothelial growth factor, among other cytokines) that ultimately leads to neovascularization and hyperplasia of the synovium and exudation of fluid.…”