Pain, 6 (1979) 183--190
i83
© Elsevier/North-Holland Biomedical Press
FIBROSITIC MYOFASCIAL PAIN IN INTERMrFrENT CLAUDICATION. EFFECT OF ANESTHETIC BLOCK OF TRIGGER POINTS ON EXERCISE TOLERANCE
BRUNO DORIGO, VITTORIO BARTOLI, DARIO GRISILLO and DANIELA BECONI
Istituto di Patologia Medica Base, University of Florence, 50134 Florence (Italy) (Accepted October 31st, 1978)
SUMMARY
The blocking of trigger points in the calf by the local injection of an anesthetic agent was performed in 15 patients with intermittent claudication. Reactive and exercise hyperemia, work load and duration of exercise were recorded before and after.infiltration of the trigger points. Reactive hyperemia does not change, but the exercise tolerance of the leg significantly improves after local blocking of the trigger areas and the exercise hyperemia increases b~.cause of the higher work load. The pain pattern of intermittent claudication can be activated by the summation of abnormal input from muscles, due to contraction in the presence of anoxia, with acti~ty from trigger points. Local infiltration of trigger areas blocks their activity. The vicious cycle of pain is interrupted and the exercise tolerance of the leg is increased, without improving blood circulation.
INTRODUCTION
The pain experienced with intermittent claudication is a complex phenomenon in which different pathogenic factors need to be considered [23]. A subnormal pressure in the nutrient artery is believed to be the determining factor [27]. Blood supply is adequate for a resting muscle but inadequate for a muscle which is actively contracting. When muscular contraction takes place in the presence of anoxia, there is an accumulation of metabolites which irritate the sensory nerve endin~ in the muscle. Many substances have been considered responsible for the appearance of pain [12,19,28,29], although the prec~e metabolic dis~urbance has never been fully elucidated. However, we must consider that in patients with intermittent claudication the capacity for walking or exercise using the muscles of the calf is not
184
related quantitatively to the blood flow [11,14,15,17,21~29]. Factors other than the hemodynamic ones could be at work. Boyd et al. [7], Travellet al. [25], Arcangeli et al. [1], and Bolletti et al. [4] have emphasized the myofascial component of intermittent claudication. After analysis of the data on plethysmography, the exercise tolerance with the foot ergometer, and the trigger areas in the calf, Bartoli et al. [2] pointed out that: (1) exercise tolerance is reduced when trigger areas are present; (2) trigger areas are more severe when the blood circulation of the leg is more impaired. The present investigation aims at ascertaining whether the block of trigger points by local injection of an anesthetic agent could improve the exercise tolerance of the patient. METHODS
Fifteen male patients, aged 45--79 years, with intermittent claudication due to arteriosclerosis obliterans were studied.
Diagnostic procedure At the time of the initial visit a complete evaluation of the clinical condition of each subject was carried out. Diagnosis was made on the basis of the vascular history~ physical examination and routine laboratory tests. Arteriography was performed only in 4 cases, as necessary for correct diagnosis. The main arterial o,~clu~ion was localized at the fliac level ia two cases and in the superficial femoral -artery in thirteen.
Venous occlusion piethysmography The blood flow in the calf was measured by means of a waterfilled plethysmograph. The room temperature was 2 0 - - 2 3 ° C. Each subject rested about 20 rain in the supine position before each test. The measurements were taken at rest and during reactive and exercise hyperemia. Reactive hyperemia was ~ o d u c e d by a period of ischemia lasting 5 rain. Exercise hyperemia was recorded immediately ~ t e r muscular exercise performed in the supine position by means of an electronic foot ergometer [22], which gives direct reading of the work load. The exercise was interrupted when ~the patient experienced pain. Work load and duration of exercise werenoted. Both reactive and exercise hyperemias were recorded twice; the first time before the onset of local blocking of the trigger points, the second 1 day after the end. The following parameters were recto.deal: (1) rest or basal flow, i.e., the calf flow at rest; (2) first flow, i.e, the first hyperemic blood flow in ~,he calf measured after ischemia or exercise; (3) peak flow, i.e., the maximum blood ~ w recorded during hyperemia; (4) time of peak flow, i.e., the time in seconds when the maximum blood flow was recorded; (5) time course for recovery of basal flow, i.e, the duration of the hyperemia.
185
Recognition of trigger points Discovery of trigger points in the muscles of the calf was possible by ac~:~,~ate palpation on gastrocnemius and soleus. In accordance with Travell [24], Kraft et al. [13] and Ibrahim et al. [9], the criteria used were the following: (a) presence of a small, tender spot as big as the thumbnail which presses on it; (b) application of pressure at a trigger point evokes pain at the point and sometimes refers pain in the target zone; (c) appearance of jump sign when the fingers pinch a trigger point.
Infiltration of trigger points In accordance with Bonica [6], immediately prior to the injection the trigger area was again identified with the finger. The needle was then introduced in the same direction that pressure was exerted to elicit pain and tenderness. When the point of the needle encountered tissue that resisted its passage, and/or gave rise to tenderness and pain, the injection of the anesthetic solution was started. Infiltration was repeated the following days. Each time about 10 ml of procaine were injected. As secondary trigger areas appeared in other sites of the same muscle, after the blocking of the first one, infiltration of procaine was extended to these points. A total of 10 infiltrations were performed.
Statistical analyses The S.D. and S.E. were calculated on mean values of the calf blood flow and of the work load, recorded before and after infiltration of trigger points. Student t-test was used to determine the significance of mean differences. RESULTE
Reactive hyperemia First flow, peak flow, time of peak flow, and duration of the hyperemia do not differ significantly before and after infiltration of the trigger points in the calf. The mean values +- S.E. are referred in Table I. The typical course of reactive hyperemia is shown in Fig. 1.
Exercise capacity Work load is significantly higher after infiltration of the trigger areas in the catf (Fig. 2). Also duration of exercise is more prolonged (Table II). P value~ are
i83
© Elsevier/North-Holland Biomedical Press
FIBROSITIC MYOFASCIAL PAIN IN INTERMrFrENT CLAUDICATION. EFFECT OF ANESTHETIC BLOCK OF TRIGGER POINTS ON EXERCISE TOLERANCE
BRUNO DORIGO, VITTORIO BARTOLI, DARIO GRISILLO and DANIELA BECONI
Istituto di Patologia Medica Base, University of Florence, 50134 Florence (Italy) (Accepted October 31st, 1978)
SUMMARY
The blocking of trigger points in the calf by the local injection of an anesthetic agent was performed in 15 patients with intermittent claudication. Reactive and exercise hyperemia, work load and duration of exercise were recorded before and after.infiltration of the trigger points. Reactive hyperemia does not change, but the exercise tolerance of the leg significantly improves after local blocking of the trigger areas and the exercise hyperemia increases b~.cause of the higher work load. The pain pattern of intermittent claudication can be activated by the summation of abnormal input from muscles, due to contraction in the presence of anoxia, with acti~ty from trigger points. Local infiltration of trigger areas blocks their activity. The vicious cycle of pain is interrupted and the exercise tolerance of the leg is increased, without improving blood circulation.
INTRODUCTION
The pain experienced with intermittent claudication is a complex phenomenon in which different pathogenic factors need to be considered [23]. A subnormal pressure in the nutrient artery is believed to be the determining factor [27]. Blood supply is adequate for a resting muscle but inadequate for a muscle which is actively contracting. When muscular contraction takes place in the presence of anoxia, there is an accumulation of metabolites which irritate the sensory nerve endin~ in the muscle. Many substances have been considered responsible for the appearance of pain [12,19,28,29], although the prec~e metabolic dis~urbance has never been fully elucidated. However, we must consider that in patients with intermittent claudication the capacity for walking or exercise using the muscles of the calf is not
184
related quantitatively to the blood flow [11,14,15,17,21~29]. Factors other than the hemodynamic ones could be at work. Boyd et al. [7], Travellet al. [25], Arcangeli et al. [1], and Bolletti et al. [4] have emphasized the myofascial component of intermittent claudication. After analysis of the data on plethysmography, the exercise tolerance with the foot ergometer, and the trigger areas in the calf, Bartoli et al. [2] pointed out that: (1) exercise tolerance is reduced when trigger areas are present; (2) trigger areas are more severe when the blood circulation of the leg is more impaired. The present investigation aims at ascertaining whether the block of trigger points by local injection of an anesthetic agent could improve the exercise tolerance of the patient. METHODS
Fifteen male patients, aged 45--79 years, with intermittent claudication due to arteriosclerosis obliterans were studied.
Diagnostic procedure At the time of the initial visit a complete evaluation of the clinical condition of each subject was carried out. Diagnosis was made on the basis of the vascular history~ physical examination and routine laboratory tests. Arteriography was performed only in 4 cases, as necessary for correct diagnosis. The main arterial o,~clu~ion was localized at the fliac level ia two cases and in the superficial femoral -artery in thirteen.
Venous occlusion piethysmography The blood flow in the calf was measured by means of a waterfilled plethysmograph. The room temperature was 2 0 - - 2 3 ° C. Each subject rested about 20 rain in the supine position before each test. The measurements were taken at rest and during reactive and exercise hyperemia. Reactive hyperemia was ~ o d u c e d by a period of ischemia lasting 5 rain. Exercise hyperemia was recorded immediately ~ t e r muscular exercise performed in the supine position by means of an electronic foot ergometer [22], which gives direct reading of the work load. The exercise was interrupted when ~the patient experienced pain. Work load and duration of exercise werenoted. Both reactive and exercise hyperemias were recorded twice; the first time before the onset of local blocking of the trigger points, the second 1 day after the end. The following parameters were recto.deal: (1) rest or basal flow, i.e., the calf flow at rest; (2) first flow, i.e, the first hyperemic blood flow in ~,he calf measured after ischemia or exercise; (3) peak flow, i.e., the maximum blood ~ w recorded during hyperemia; (4) time of peak flow, i.e., the time in seconds when the maximum blood flow was recorded; (5) time course for recovery of basal flow, i.e, the duration of the hyperemia.
185
Recognition of trigger points Discovery of trigger points in the muscles of the calf was possible by ac~:~,~ate palpation on gastrocnemius and soleus. In accordance with Travell [24], Kraft et al. [13] and Ibrahim et al. [9], the criteria used were the following: (a) presence of a small, tender spot as big as the thumbnail which presses on it; (b) application of pressure at a trigger point evokes pain at the point and sometimes refers pain in the target zone; (c) appearance of jump sign when the fingers pinch a trigger point.
Infiltration of trigger points In accordance with Bonica [6], immediately prior to the injection the trigger area was again identified with the finger. The needle was then introduced in the same direction that pressure was exerted to elicit pain and tenderness. When the point of the needle encountered tissue that resisted its passage, and/or gave rise to tenderness and pain, the injection of the anesthetic solution was started. Infiltration was repeated the following days. Each time about 10 ml of procaine were injected. As secondary trigger areas appeared in other sites of the same muscle, after the blocking of the first one, infiltration of procaine was extended to these points. A total of 10 infiltrations were performed.
Statistical analyses The S.D. and S.E. were calculated on mean values of the calf blood flow and of the work load, recorded before and after infiltration of trigger points. Student t-test was used to determine the significance of mean differences. RESULTE
Reactive hyperemia First flow, peak flow, time of peak flow, and duration of the hyperemia do not differ significantly before and after infiltration of the trigger points in the calf. The mean values +- S.E. are referred in Table I. The typical course of reactive hyperemia is shown in Fig. 1.
Exercise capacity Work load is significantly higher after infiltration of the trigger areas in the catf (Fig. 2). Also duration of exercise is more prolonged (Table II). P value~ are
