"Prespondylosis" and some pain syndromes following denervation supersensitivity

Segmental Dysfunction

Spinal segmental dysfunction, although used in clinical practice by medical acupuncturists, musculoskeletal physicians, physiotherapists and osteopaths, is not a concept which is familiar to the majority of medical practitioners. The concept implies that a problem in the function of a spinal segment may cause symptoms without necessarily being caused by physical pathology.

Studies of the dysfunctional spinal segment have shown that physical stress, emotional stress and visceral disease all cause a reaction at the dysfunctional segment more easily than at normal segments. In the same way that individuals may have asymptomatic latent trigger points which may later become symptomatic, so individuals may have asymptomatic dysfunction which later becomes symptomatic under the influence of appropriate stimuli.

There is some evidence that the clinical features of segmental dysfunction may be mediated by the sympathetic nervous system. The detection of segmental dysfunction is a clinical skill worth developing and the properties of the dysfunctional segment are worthy of further research.

Myofascial Trigger Points: Pathophysiology and Correlation with Acupuncture Points

A review is made of recent studies on myofascial trigger points (MTrP) and their mechanism is discussed. Clinical and basic science studies have shown that there are multiple MTrP loci in a MTrP region. A MTrP locus contains a sensory component (sensitive locus) and a motor component (active locus). A sensitive locus is a point from which tenderness or pain, referred pain, and local twitch response can be elicited by mechanical stimulation. Sensitive loci (probably sensitised nociceptors) are widely distributed in the whole muscle, but are concentrated in the endplate zone. An active locus is a site from which spontaneous electrical activity can be recorded. Active loci appear to be dysfunctional endplates since spontaneous electrical activity is essentially the same as the electrical activity reported by neurophysiologists as that recorded from an abnormal endplate. A MTrP is always found in a taut band which is histologically related to contraction knots caused by excessive release of acetylcholine in abnormal endplates. Both referred pain and local twitch response are mediated through spinal cord mechanisms, as demonstrated in both human and animal studies.

The pathogenesis of MTrPs appears to be related to integration in the spinal cord of response to the disturbance of nerve endings and abnormal contractile mechanism at multiple dysfunctional endplates. There are many similarities between MTrPs and acupuncture points including their location and distribution, pain and referred pain patterns, local twitch responses (de qi), and possible spinal cord mechanism.

Complex regional pain syndrome following lateral lumbar interbody fusion

The minimally destructive lateral transpsoas approach to the spine has been used in the treatment of various lumbar spinal pathologies. Approach-specific complications have been reported due to the unique surgical corridor and lateral anatomical structures. The authors report a case of complex regional pain syndrome (CRPS) following interbody cage placement utilizing the lateral lumbar transpsoas approach. A review of the literature is discussed. Further clarification of the mechanism of CRPS and its treatments remains crucial for the fine-tuning of novel surgical techniques and complication avoidance during the development of these techniques.

Involvement of NGF in the rat model of persistent muscle pain associated with taut band

Myofascial pain syndrome (MPS) is an important clinical condition characterized by chronic muscle pain and a myofascial trigger point (MTrP) located in a taut band (TB). However, its pathogenic mechanism is still unclear. We developed an animal model relevant to conditions of MPS, and analyzed the mechanism of the muscle pain in this model. We applied eccentric contraction (EC) to a rat's gastrocnemius muscle (GM) for 2 weeks, and examined the mechanical withdrawal thresholds, histological changes, and expressions and contents of nerve growth factor (NGF). The mechanical withdrawal threshold decreased significantly at the next day of first EC and continued up to 9 days after EC. TBs were palpable at 3 to 8 days after initiation of EC. In EC animals, necrotic and regenerating muscle cells were found significantly more than in control animals. In EC animals, NGF expressions in regenerating muscle cells and NGF contents of GM were significantly higher than control animals. Administration of NGF receptor (TrkA) inhibitor K252a showed significant suppression of mechanical hyperalgesia in EC animals. Repeated EC induced persistent mechanical muscle hyperalgesia associated with TB. NGF expressed in regenerating muscle cells may have an important role in persistent mechanical muscle hyperalgesia which might be relevant to pathogenesis of MPS.

PERSPECTIVE

The present study shows that NGF expressed in regenerating muscle cells is involved in persistent muscular mechanical hyperalgesia. NGF-TrkA signaling in primary muscle afferent neurons may be one of the most important and promising targets for MPS.

The effect of Gunn's intramuscular stimulation for postherpetic neuralgia -A report of 4 cases-

Herpes zoster is the consequence of reactivation of latent varicella zoster virus from dorsal root ganglia. Postherpetic neuralgia (PHN) may be diagnosed when pain persists in a dermatomal pattern long after the vesicular erruption has healed. PHN is a kind of neuropathic pain. The pathophysiology of PHN is uncertain, but neuropathic pain due to denervation supersensitivity may be important to understand the pathophysiology of PHN. Numerous treatment have been introduced for the management of PHN, but no methods that results in complete remission. Gunn's intramuscular stimulation (IMS) is one of the best treatment of chronic pain, especially neuropathic pain. We tried Gunn's IMS for treatment of PHN patients affecting thoracic dermatomes. As a result, the visual analogue scale (VAS) was decreased from 7-8 to 2-3 and the result were satisfactory. The purpose of this case report is to introduce the Gunn's IMS and review our experience for the treatment of PHN.

Are tender points associated with cervical radiculopathy?

OBJECTIVE

To determine if there is an association between cervical radiculopathy and tender spots in the neck and upper extremity on the side of radiculopathy.

DESIGN

Prospective cross-sectional study.

SETTING

Outpatient spine clinic within an academic institution.

PARTICIPANTS

Convenience sample of 16 subjects with unilateral cervical radiculopathy. Twelve subjects had C7 radiculopathy and 4 had C6 or C8 radiculopathy.

INTERVENTION

Bilateral pain-pressure threshold measurement (14 muscles) of the neck and upper extremity.

MAIN OUTCOME MEASURE

Side-to-side difference in pain-pressure threshold.

RESULTS

Differences in frequency of tender spots were found only in the deltoid and flexor carpi radialis. Overall, more tender spots were found on the side of radiculopathy (75 vs 34, P < .01). Among subjects with C7 radiculopathy, the number of tender spots in C7 innervated muscles was greater on the side of radiculopathy (23 vs 7, P < .02). In contrast, no significant difference in the number of tender spots between sides was found when only non-C7 innervated muscles (P > 0.1) were considered.

CONCLUSIONS

Cervical radiculopathy was associated with increased tender spots on the side of radiculopathy, with predilection toward muscles innervated by the involved nerve root.

Case report: Myofascial pain syndrome: a double crush-like appearance

OBJECTIVE

To discuss the case of a patient with myofascial pain syndrome that appeared similar to double crush syndrome.

CLINICAL FEATURES

This is a case report of a 45-year old female who presents to the private practice clinic with the same signs and symptoms of carpal tunnel syndrome, 1 year post-carpaltunnel surgery. The history is consistent with injuries that result in double crush syndrome and thoracic outlet syndrome. The patient history includes a motor vehicle accident (MVA) in 1963 that resulted in a prolonged hospital stay and fracture of a cervical vertebral (C4) body. She fractured the olecranon process of the right elbow during a fall in 1970's. She has smoked approximately 1 pack a day for 20 years. Her job involves long periods of sitting at a keyboard and in a car. All of these portions of the patient history are possible factors in the clinical signs and symptoms of double crush syndrome.

INTERVENTION AND OUTCOME

Treatment involved chiropractic manipulation and physical therapy modalities for the elimination of pain and returning the patient's full range of motion in the wrist, elbow, shoulder and cervical spine. After range of motion was restored, a home exercise program was initiated. The home exercise program included a return to past sporting activity and active, resistive (Theraciser band) activities for the elbow and cervical spine. Also a reduction in smoking was initiated as part of the patient's treatment plan.

CONCLUSION

It is our contention that patients who have electromyographic (EMG) demonstrable carpal tunnel syndrome need a cervical spine workup and a period of conservative care to include skilled manipulation, physical therapy and home exercises before surgery is recommended.

Physical findings in patients with chronic intractable benign pain of the neck and/or back

Chronic intractable benign pain (CIBP) is defined as non-neoplastic pain of greater than 6 months duration without objective physical findings and known nociceptive peripheral input. To test the CIBP concept, 283 consecutive chronic pain patients were examined independently by a neurosurgeon and physiatrist and only congruent physical findings were coded. Because they did not fit the CIBP definition, patients with the following primary treatment diagnoses were eliminated: degenerative disease of the spine and spinal stenosis; degenerative disease of the hips; radiculopathy; malignancy; deafferentation pain; and miscellaneous. Eliminated, also, were patients with any one finding indicative of a root compression syndrome, leaving 90 low back and 34 neck patients. These patients had abnormal physical findings in 7 categories: tender points/trigger points; decreased ranges of motion in back or neck; non-anatomical sensory loss; rigid musculature; decreased range of hip motion; gait disturbance; and miscellaneous non-neurologic signs. Low back CIBP patients had the following distribution among the 7 categories: 0% had findings of all 7; 1.1% had 6; 13.3% had 5; 24.4% had 4; 25.6% had 3; 26.7% had 2; 8.9% had 1; and 0% had none. Neck CIBP patients, in which only the first 4 categories of physical findings were applicable had the following distribution: 2.9% had 4; 41.2% had 3; 35.3% had 2; 20.6% had 1; and 0% had none. It was concluded that CIBP patients do have abnormal physical findings indicative of musculoskeletal disease: possibly fibrositis and/or specific myofascial syndromes, as sources of peripheral nociception. These findings question the validity of the CIBP concept and point to the need for a careful, all-inclusive physical examination as a basic initial requirement in the classification of chronic pain patients.