Algometry in the daily practice of pain management.

PURPOSE: This is a review article to update the clinical applications of pressure pain sensitivity (PPS) measurement by pressure algometry (PA) [1,2]. BASIC PROCEDURES: The basic literature on pressure algometry has been reviewed with emphasis on new developments. The author's and his co-workers' experience with PA, extending several years, are also included along with some unpublished research results. FINDINGS: The high reliability and validity of PA for quantification of PPS has been proven by several authors. The specificity and sensitivity of PA in detection of trigger points (TrPs) is also very good. PA is also useful in evaluation of treatment results. PA can document the decreased PPS after 'preinjection (regional) blocks' administered prior to trigger point injections (TPIs). A study of ten patients with failed back surgery included 20 muscles. PA documented long-term improvement (150 days) which corresponded to a decrease in pain rating. Treatment consisted of needling and infiltration of the entire trigger point (TrP) extending to taut band. Another study showed that physicians were unable to produce 4 kg of pressure, which is critical for diagnosis of fibromyalgia. CONCLUSIONS: Quantification of fibromyalgia diagnosis by PA is necessary for abnormal tenderness (pain on 4 kg pressure). The critical pressure for TrP, tender spots is a pressure pain threshold lower by 2 kg/cm2 relative to a normally sensitive corresponding control point.

Injection techniques in the management of local pain.

This is a review of local anesthetic (LA) injections and infiltrations particularly combined with 'needling' for management of local musculoskeletal pain. New techniques are described including preinjection blocks (PIBs) which consist of blocking the sensory input from an area prior to giving an injection. PIBs prevent pain which would be caused by needle penetration of sensitive tissue. Needling and infiltration (N and I) with 1% lidocaine has been performed after PIB in 179 tender spots (TSs), trigger points (TrPs), and muscle spasms by the author, in 123 patients with the goal to relieve pain and promote healing. The immediate effect after the procedure as well as long-term results from 1 week to 7 months have been evaluated independently by a physiatrist experienced with injections (Dr. Tae Mo Chang). N and I extending over the entire taut band of abnormal muscle fibers, caused effective relief of pain and functional improvement in tender spots (TSs), trigger points (TrPs) and in muscle spasm caused by a variety of conditions including: acute and chronic sports and work injuries, motor vehicle accidents, muscle and ligament sprains (supraspinous, sacroiliac), overuse and repetitive stress syndromes, tennis elbow; local injuries or radicular irritation; and local inflammations such as bursitis, tendinitis, and osteoarthritis; and traumatic dystrophy, a type of reflex sympathetic dystrophy. Needling and infiltration of trigger areas and tender spots is effective treatment in several conditions. Pre-injection blocks allow the performance of the N and I of tender areas without pain.

Diagnosis and treatment of myofascial pain.

The importance of muscle as a source of pain should not be underestimated. Proper diagnosis of the four types of muscle pain (tension, spasm, muscle deficiency, and trigger points) is essential to effective management. Pain-diagnostic instruments can quantify tenderness and spasm and help evaluate treatment results.

Effects of warming imagery aimed at trigger-point sites on tissue compliance, skin temperature, and pain sensitivity in biofeedback-trained patients with chronic pain: a preliminary study.

13 subjects were trained in biofeedback and self-regulation strategies for reducing chronic pain. Upon demonstrating ability to hand warm, subjects were exposed to an imagery exercise designed to increase skin temperature at trigger-point sites, which are small tender irritative foci located in the soft tissue. Skin temperature, tissue compliance, and pressure-pain sensitivity were recorded before and after imagery intervention. Subjects showed significant increases in skin temperature and muscle relaxation at trigger-point sites and decreases in pressure-pain sensitivity. This suggests that localized trigger-point warming may be an effective adjunct in treating chronic pain.

Specific inhibition of the synthesis of influenza virus late proteins and stimulation of early, M2, and NS2 protein synthesis by 3-deazaadenosine.

3-Deazaaristeromycin and 3-deazaadenosine (3DA-Ado) both interfere with the methylation of RNA, but only 3DA-Ado is metabolized to the corresponding homocysteine derivative. In contrast to 3-deazaaristeromycin, 3DA-Ado inhibits the synthesis of late influenza A virus proteins in chicken embryo cells (CEC), while it causes an overproduction of early proteins and of the nonstructural proteins NS2 and M2. Only the former effect of 3DA-Ado can be reversed by concomitant addition of adenosine, but not by guanosine. 3DA-Ado acts only early in the infectious cycle and, after removal of the drug, its effect on the yield of infectious virus is reversible. It can be significantly enhanced by homocysteine thiolactone. Except for the M gene, synthesis of viral mRNA is not significantly affected by 3DA-Ado. We conclude that 3DA-Ado acts via its homocysteine derivative by interfering with a specific post-transcriptional modification of viral mRNA and on splicing of specifically the M mRNA. In L-cells influenza viral protein synthesis is comparable to that in CEC in the presence of 3DA-Ado in that there is only little HA and M1 synthesized, and a severe overproduction of NS2 is observed. Under the experimental conditions 3DA-Ado has no inhibiting effect on the replication of other RNA viruses like Newcastle disease virus, Semliki Forest virus, or West Nile virus whose RNA is not methylated, since they do not have a nuclear phase during replication.

Documentation of myofascial trigger points.

Two basic diagnostic features of myofascial trigger points (TPs), namely, local tenderness and alteration of tissue consistency (such as in taut bands, muscle spasm), can be documented quantitatively by simple hand-held instruments. A pressure threshold meter (algometer) assists in location of TPs and their relative sensitivity. A side-to-side difference exceeding 2kg in comparison with normal values indicates pathologic tenderness. The effect of treatment can be quantified. Pressure tolerance, measured over normal muscles and shin bones, expresses pain sensitivity. Myopathy is suspected if muscle tolerance drops below bone tolerance. Tissue compliance measurement documents objectively and quantitatively alteration in soft tissue consistency. Muscle spasm, tension, spasticity, taut bands, scar tissues, or fibrositic nodules can be documented. The universal clinical dynamometer is used as part of a physical examination to quantify weakness. Thermography (heat imaging) demonstrates discoid shaped hot spots over TPs. Muscle activity, spasm, or contraction is visualized as increased heat emission in the shape of the active muscle.

Tissue compliance meter for objective, quantitative documentation of soft tissue consistency and pathology.

A new instrument is described, the tissue compliance meter (TCM), for quantitative and objective recording of soft tissue consistency. This quality is appreciated at present only by the subjective method of palpation. Use of the TCM therefore offers a method to quantify palpation of tissue consistency and to document findings objectively. The handheld instrument allows immediate and simple reading of the depth of penetration of a rubber disc at a known pressure. The relation between the achieved penetration and employed pressure expresses the compliance. The TCM consists of a rubber disc with the surface of 1 cm2 attached to a force gauge. The depth of penetration of the rubber tip is indicated by a disc which slides on the shaft of the force gauge. Normal values were established for men and women over muscles which are frequently affected by spasm. Tissue compliance measurement can document changes in soft tissue consistency which occur in muscle spasm, spasticity, swelling, tumors, lumps, hematomas, etc. Use of the TCM provides the most sensitive and earliest objective indication of either healing and resolution in soft tissue pathology or occurrence of complications. Changes in muscle tone such as reduction of spasm, tension, or spasticity can be recorded. The effects of different types of physical therapy can thus be documented objectively.

Pressure threshold meter: its use for quantification of tender spots.

The pressure threshold meter (PTM) and its use for evaluation of tender spots and trigger points are described. Pressure threshold is the minimum pressure inducing pain or discomfort. The PTM consists of a force gauge (11 kg range) to which a rubber disc with lcm2 surface is attached. This surface has been proven adequate for quantification of deep tenderness in soft tissues. Normal threshold values were established in 50 volunteers, 24 men and 26 women, at nine different sites frequently affected by trigger points, including the trapezius, supraspinatus, infraspinatus, teres major, lumbar paraspinals (2 sites), gluteus and pectoralis muscles. The deltoid, where muscle sensitivity is usually normal, was used as a reference. PTM is used clinically for quantification of tenderness for medicolegal purposes, but primarily to prove the presence of trigger points to patients and health professionals. Reaction to various forms of treatment such as physiotherapy and drugs can be assessed quantitatively. When trigger point injections are properly administered to affected areas, pressure threshold measurements usually increase by 4 kg/cm2. Failure to increase the reading indicates that the injection was incomplete and the procedure should be repeated. The PTM can be used for monitoring tenderness, inflammation, arthritis activity, and fibrositis.

Pressure tolerance over muscles and bones in normal subjects.

Pressure tolerance (PTo) is the maximum force a person can tolerate without excessive effort. Pressure threshold (PT) is the minimum force that induces discomfort or pain. Both measures have proven to be extremely useful in evaluating patients with chronic pain. This study documents PTo in 50 healthy, pain-free subjects. Measurements were taken with a rubber disc of 1cm2 attached to a pressure gauge calibrated in units of force, (newtons/cm2). Measurements were taken over two muscle sites: supraspinatus and deltoid, and over two bone sites: thumb and midtibia; measurements were taken on each subject's right and left sides. Pressure over the skin was gradually increased by 10 newtons/sec until the subject examined said "stop." Normal values for PTo were established for men and women; PTo is slightly higher in men. Statistical analysis failed to demonstrate significant difference in PTo over corresponding opposite sides. Identical contralateral findings prove the excellent reproducibility and validity of pressure tolerance measurements. Clinical applications include: generalized myopathy is considered when muscle PTo is lower than bone (reversal of normal relation). The condition is caused usually by treatable endocrine deficiency. Low pain tolerance (hyperalgesic syndrome) is manifested by decreased PTo over both muscles and bones. Special therapeutic approaches are necessary for these patients. Functional disorders are characterized by lower PTo than in organic disease.

Spectrum analysis of large toe plethysmographic waveshape.

To assess plethysmographic waveform diagnostic utility in peripheral vascular disease, a spectrum analyzer was attached to the output of a conventional mercury strain gauge sensor. The resulting quantified waveforms were compared with geometrically determined waveform characteristics and resting ankle pressure ratios for a group of 16 men who ranged from healthy to severely occluded (lower extremities). Of the various harmonics contained within the waveform, second harmonic magnitude best correlated with those geometric waveform characteristics believed to possess diagnostic value. Second harmonic magnitude was positively related (0.9 correlation coefficient) to the 1.33 power of resting ankle pressure ratio. Because it does not require exercise or pressure cuffs, spectrum analyzer waveform based diagnosis may be suited for mass screening purposes.