Fibromyalgia: Part IV: Long term outcome as measured by dolorimetry..
Flechas, J.D and Rosner, M.J.
Objective: Previous studies of patients with spinal cord injury, such as laceration, compression, and/or injury have described a pain syndrome, which is descriptive of fibromyalgia syndrome (FMS) pain. We hypothesized that dolorimeter (DOL) scores would go up as a function of time after surgery to decompress the spinal cord in patients with FMS. Methods: All patients met the American College of Rheumatology classification criteria for FMS. Patients also had to demonstrate on MRI, spinal cord compression. Before surgery was considered, they had to show neurological dysfunction, such as numbness, limb weakness, neurally mediated hypotension etc. If their symptoms were well controlled by medication, surgery was not a consideration. At no time was surgery done for FMS pain. DOL was done at the time of initial office visit (IOV), prior to surgery (PTS), and at different times post op (PO) over the next year. Data was analyzed by student t test. Avg age 45. Conclusion: Spinal cord pain, which initially is mistaken as FMS pain, does statistically improve with decompression of the cord. The data supports that pain thresholds improve as a function of time.
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Results: Units are as follows:
DOL (kg/cm2)+SEM, Time (weeks)+SEM
| Time |
DOL |
N |
Std Dev |
P-Value |
| IOV |
43.7+2.7 |
62 |
21 |
|
| PTS |
43.2+3.2 |
63 |
21 |
|
| 6.4+.2 |
66.6+5.2 |
37 |
32 |
.00007 |
| 13+.4 |
79.1+7.5 |
31 |
42 |
.002 |
|
INTRODUCTION: Previous studies of patients with spinal cord injury, such as laceration, compression, and or injury have described a pain syndrome, which is descriptive of fibromyalgia syndrome (FMS) pain1, 3. The patients in these studies described their pain as burning and/or stinging. They also had a feeling of pulling or pressure. Cramping, stabbing, and tingling/numbness were also seen. Exercise would make one half of them worse. Tension, overexertion and changes in weather were said to aggravate their pain.
OBJECTIVE: Dolorimeter measurements have been used for years to assess how much pain fibromyalgia patients have. We hypothesized that dolorimeter (DOL) scores would increase as a function of time after surgery to decompress the spinal cord in patients with FMS. Methods: All patients met the American College of Rheumatology classification criteria for FMS. Patients also had to demonstrate on MRI, spinal cord compression. No patients with spinal cord laceration, or injury were considered for this study. All patients were neurologically abnormal, with numbness, ataxia, dysphagia, dizziness, cranial nerve malfunction, limb weakness, etc. (see part I). All patients suffered from NMH/POTS and had abnormal tilt table examinations. The patients during this study were noted to have either a hypoplastic posterior fossa (roughly synonymous with Chiari malformation), and/or cervical spinal stenosis. The latter was usually developmental with degenerative change superimposed. If their symptoms were well controlled by medication, surgery was not a consideration. At no time was surgery done for FMS pain. DOL was done at the time of initial office visit (IOV), prior to surgery (PTS), and at different times post op (PO) over the next year. Data were entered into Systat 7.0 and analyzed by student’s t-test. Average patient age was 45.
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Units: DOL (kg/cm2) + SD + SEM, Time (weeks) + SEM
DISCUSSION: The pain experienced by patients in this series decreases over time (Part III). Dolorimetry is a measure of pain threshold as opposed to pain itself. These data demonstrate that the brainstem and upper spinal cord are capable of altering pain threshold when compressed and that decompression of these areas is capable of reversing toward normal those thresholds. The consistent improvement over the first year after surgery shows that this is a gradual and progressive process with improvement over time for most patients. It is also important to view the altered pain threshold with local pain produced by the pressure stimulus as a central event, and not necessarily due to altered tissue function or structure. This is most clearly demonstrated in those with overt spinal cord injury1, 3. The pain in this group of fibromyalgia patients is myelopathic, while the issue is largely semantic, one could argue that this group of patients does not have fibromyalgia. Anatomically, the most direct etiology for a reduction in pain threshold with the brainstem and/or upper spinal cord compression is interference with the outflow of descending nociceptive control fibers originating in the nucleus raphe magnus and paragigantocellularis of the medulla oblongata2.
Conclusions:
1. Pain threshold as measured by dolorimetry can be returned toward normal after spinal and/or brainstem decompression.
2. Dolorimetry and the concept of “number of tender points” do not discriminate between cord compression and tissue dysfunction from other etiologies.
Reference List
Botterell, E. H., Callaghan, J.C. an Jousse, A.T.: Pain in Paraplegia: Clinical management and surgical treatment. Proc. R. Soc Med 47:281-288,1954.
Jessell TM, Kelly DD: Pain and analgesia, in Kandel ER, Schwartz JH, Jessell TM (eds): Principles of Neural Science, ed 3. Norwalk, Connecticut: Appleton & Lange, 1991, pp 385-399.
3. Nepomuceno, C., Fine, P. R., Richards, J. S., et al: Pain in patients with spinal cord injury. Arch Phys Med Rehabil 60:606-608, 1979.
National Fibromyalgia Research Assn.
Neuro and New Treatment Modalities
Symposium—Portland, OR—Oct 2002
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