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Transcutaneous electric nerve stimulation (TENS) during distension shoulder arthrography: a controlled trial
Pain, 64 (1995) 265-267
265
© 1995 Elsevier Science B.V. All rights reserved 0304-3959/95/$09.50
PAIN 2897
Transcutaneous electric nerve stimulation (TENS) during distension shoulder arthrography: a controlled trial B r u n o M o r g a n a, *, A n d r e w R. J o n e s a, Kevin A. M u l c a h y a D a v i d B. Finlay a and B e v e r l y Collett b a Department of Radiology and b Pain Management Clinic, Leicester Royal Infirmary, Infirmary Square, Leicester LE1 5 W W (UK)
(Received 26 January 1995, revisionreceived22 March 1995, accepted 10 May 1995)
Summary Transcutaneous electric nerve stimulation (TENS) is a safe and simple form of analgesia but is little used as an adjunct to local anaesthesia during routine procedures. This trial investigates the use of TENS in the radiology department using distension shoulder arthrography for 'frozen shoulder', a moderately painful procedure, as a model. Sixty patients With a clinical diagnosis of 'frozen shoulder' were randomised to receive high-intensity TENS, low-intensity TENS or to act as controls. A standard procedure was then performed. Following the procedure patients completed a visual analogue pain scale. Mean recorded pain levels were lower in the TENS groups with a 50% difference between the high-intensity group and a 38% difference between the low-intensity group as compared to control (difference statistically significant P < 0.01 and P < 0.05, respectively). TENS was well tolerated by patients. The 50% reduction in mean pain levels supports the use of TENS for routine painful procedures.
Key words: Transcutaneous electric nerve stimulation; Adhesive capsulitis; Arthrography
Introduction Distension arthrography for 'frozen shoulder' (adhesive capsulitis) has been found to be an effective therapeutic procedure and is recognised as painful (Hulstyn and Weiss, 1993; Mulcahy et al. 1994). Local anaesthesia is used but is unhelpful when cannulating the inflamed capsule and distending the joint. Transcutaneous electric nerve stimulation (TENS) is a safe and simple form of analgesia showing beneficial results in chronic musculoskeletal pain (Deyo et al. 1990a), dental pain (Ottoson et al. 1981), labour pain (Augustinsson et al. 1977) and post operative pain (Hargreaves and Lander 1989). However, little work has been done to assess its role in routine procedures. Lander and Fowler-Kerry (1993) have shown a small but significant benefit of TENS in venepuncture of children. Rawat et al. (1991) were unable to show any advantage of TENS during biliary lithotripsy. This may reflect an increased
* Corresponding author: Dr. B. Morgan, Department of Radiology,
Leicester Royal Infirmary,InfirmarySquare, Leicester LE1 5WW, UK. Tel.: (44) 1533-541414~ext. 6719; FAX: (44) 1533-586721. SSDI 0304-3959(95)00107-7
efficacy of TENS for superficial rather than deep pain (Smith et al. 1986). Many trials concerning TENS show conflicting results with good subjective patient response without objective measured benefit. This may reflect the difficulties in conducting a blinded, controlled trial with a physical therapy such as TENS. Although pain relief is not a major problem in radiology departments, there are many procedures performed for which a safe adjunct to local anaesthesia would improve patients comfort and be particularly helpful for those anxious about pain. We have designed this trial to investigate the use of TENS for routine procedures in the radiology department using distension shoulder arthrography as a model.
Method Ethical approval was obtained from the Leicester Royal Infirmary ethics committee. Sixty patients with a clinical diagnosis of frozen shoulder referred for distension arthrography were sequentially randomised to receive high-intensity TENS, low-intensity TENS, or to act as controls. Informed consent was obtained from all groups. Age, sex and analgesic medicationswere noted. All patients had the procedure fully explained. The TENS groups had the use of
266 TENS explained. The TENS unit was then attached (Neen Pain M a n a g e m e n t Systems, Suffolk, UK). Two 3 × 3 cm skin electrodes (radiolucent) were then placed either side of the shoulder joint. The frequency level was set to 80 Hz which is in the optimum range (Johnson et al. 1989). The high-intensity TENS group had the amplitude of stimulation slowly increased until muscle fasciculation or discomfort occurred. The unit was then adjusted to the m a x i m u m comfortable level. In the low-intensity group the unit was set to a constant level just above the sensory threshold. The TENS unit was allowed to function for 20 min before the procedure, allowing optimum efficacy (Johnson et al. 1989), while control radiographs were taken. A standard procedure was performed by one of the authors (D.F.). The skin and soft tissues were infiltrated with 2 - 3 ml of 1% lignocaine. The shoulder joint was then cannulated with a 22-ga spinal needle u n d e r fluoroscopic control. Iopamidol (5-10 ml), 1 ml of 1% lignocaine and 40 mg of triamcinolone acetate were introduced and the shoulder was distended with 20-30 ml of air. Although we were unable to blind the operator to the control group the 2 TENS groups were double-blinded. After the procedure the TENS unit was removed and the patients were asked to fill in a 100-mm visual analogue pain scale (VAS) regarding the pain of the procedure with one end representing no pain, the other the most severe pain imaginable (Huskinsson 1974; Gilbert et al. 1986). T h e operator was not involved in the administration of the pain questionnaire. The arm was then manipulated and further radiographs taken. The results were analysed for statistical significance using the Wilcoxon rank-sum method.
PATTERN OF PAIN LEVELS BETWEEN THE HIGH INTENSITY TENS GROUP AND CONTROL
6
==4 uJ
1 TENS
i
I[]CONTROLI
3 2
o
o
o
~
~
~
~
~
~
PAIN LEVEL (mm o n V.A.S scale)
Fig. 1.
was well received by patients. Fig. 1 demonstrates the pattern of recorded pain levels between the high-intensity TENS group and the control group. It can be seen that no patients in the TENS group recorded pain levels in the top half of the pain scale.
Results
The results are shown in Table I. The patients in the 3 groups were comparable for age and sex. Two patients in the high-intensity group and 1 patient in the low-intensity group had taken paracetamol in the 6 h prior to the procedure. Two patients in the control group had taken ibuprofen in the 6 h prior. Their subsequent pain levels were not substantially different from the mean pain levels in their groups. No other analgesic medication had been taken. Mean recorded pain levels show a 50% difference in the high-intensity group and a 38% difference in the low-intensity group as compared to control. These differences are statistically significant by the Wilcoxon rank-sum method (P < 0.01 and P < 0.05, respectively). The 20% difference in mean pain levels between the high- and low-intensity group does not reach statistical significance. No problems were associated with the use of TENS which
TABLE I PAIN LEVELS R E C O R D E D IN T R I A L G R O U P S Group
High-intensity TENS Low-intensity TENS Control
Number Age (years) Sex ( M \ F ) VAS
20 44.5 (SD + 13) 10\10 19 (SD + 15.5) a
20 44.5 (SD + 11) 10\10 23.5 (SD + 20) b
20 45 (SD + 15) 8\12 37.5 (SD + 25)
VAS, m e a n recorded pain level on VAS ( \ I 0 0 mm). a Difference from control statistically significant ( P < 0.01). b Difference from control statistically significant ( P < 0.05).
Discussion
The design of trials for physical therapies can often be criticised as it is impossible to fully blind the study and use adequate placebo controls. In the case of TENS there is no placebo equivalent of sensory stimulation. Deyo et al. (1990b) showed that greater than 40% of patients in a sham TENS group (TENS unit switched on with red light showing but with no output) were not convinced that their TENS unit was functioning. This is the method used by most trials concerning TENS. Furthermore the control group cannot be blinded from the operator as the use of TENS is difficult to disguise. For this reason we did not use sham TENS but 2 groups with functioning TENS. This avoids the problem of an inadequate placebo group but makes it more difficult to separate a real from placebo effect. The high-intensity group is operated at the maximum comfortable level which has been shown to be its optimum setting (Johnson et al. 1989; Leandri et al. 1990). The low-intensity group is operated at just above the sensory threshold. Although TENS at this level has less activity than at higher settings some effect was expected. One study has suggested that even sub-threshold TENS has some effect (Lehmann et al. 1986). The results show the hypothesised pattern of reduced pain levels with increasing TENS stimulation although the difference between the high- and low-intensity groups does not reach statistical significance making a placebo effect for both groups a possibility.
267
The use of high-intensity TENS was also associated with no patients recording pain levels in the top half of the pain scale. Although applying the TENS unit and allowing time for maximum efficacy may be time-consuming, the 50% differertce in pain levels between the high-intensity TENS group and control, along with the high patient satisfaction with TENS, support a role for its use in routine procedures.
References Augustinsson, L.E., Bohlin, P., and Bundsen, P., Pain relief during delivery by transcutaneous electric nerve stimulation (TENS), Pain, 4 (1977) 59-65. Deyo, R.A., Walsh, N.E., Martin, D.C., Schoenfield, L.S., and Ramamurthy S.A., A controlled trial of transcutaneous electric nerve stimulation (TENS) and exercise in chronic low back pain, N. Engl. J. Med., 322 (1990a) 1627-1634. Deyo, R.A., Waish, N.E., Schoenfeld, L.S., and Ramamurthy, S., Can trials of physical treatments be blinded. The example of transcutaneous electric nerve stimulation for chronic pain. Am. J. Phys. Med. Rehab., 69 (1990b) 6-10. Gilbert, J.M., Gledhill, T., Law, N., and George, C., Controlled trial of transcutaneous electric nerve stimulation (TENS) for post operative pain relief following inguinal herniorrhaphy. Br. J. Surg., 73 (1986) 749-751. Hargreaves, A., and Lander, J.. Use of transcutaneous electric nerve
stimulation (TENS) for postoperative pain. Nurs. Res., 38 (1989) 159-161. Hulstyn, M.J., and Weiss, A.P., Adhesive capsulitis of the shoulder. Orthop. Rev., 22 (1993) 425-433. Huskinsson, E.C., Measurement of pain, Lancet, ii (1974) 1127-1131. Johnson, M.I., Ashton, C.H., Bousfield, D.R., and Thompson, J.S., Analgesic effects of different frequencies of transcutaneous electric nerve stimulation on cold induced pain in normal subjects, Pain, 39 (1989) 231-236. Lander, J., and Fowler-Kerry, S., Transcutaneous electric nerve stimulation (TENS) for children's procedural pain, Pain, 52 (1993) 209-216. Leandri, M., Parodi, C.I., Corrieri, N., and Rigardo, S., Comparison of transcutaneous electric nerve stimulation treatments in hemiplegic shoulder pain. Scand. J. Rehab. Med., 22 (1990) 69-71. Lehmann, T.R., Russell, D.W., and Spratt, K.F., Efficacy of electroacupuncture and transcutaneous electric nerve stimulation in the rehabilitation of chronic low back pain patients, Pain, 26 (1986) 277-290. Mulcahy, K.A., Baxter, A.D., Oni, O.O.A., and Finlay, D.B., The value of shoulder distension arthrography with intra-articular injection of steroid and local anaesthesia: a follow up study. Br. J. Radiol., 67 (1994) 263-266. Ottoson, D., Ekblom, A., and Hansson, P., Vibratory stimulation for the relief of pain of dental origin, Pain, 10 (1981) 37-45. Rawat, B., Genz, A., Fache, J.S., Ong, N.Y., Coldman, A.J., and Burhenne, H.J., Effectiveness of transcutaneous electric nerve stimulation (TENS) for analgesia during biliary lithotripsy. Invest. Radiol., 26 (1991) 866-869. Smith, C.M., Guralnick, M.S., Gelfand, M.M., and Jeans, M.E. The effect of transcutaneous electric nerve stimulation (TENS) on post caesarean pain, Pain, 27 (1986) 181-193.
265
© 1995 Elsevier Science B.V. All rights reserved 0304-3959/95/$09.50
PAIN 2897
Transcutaneous electric nerve stimulation (TENS) during distension shoulder arthrography: a controlled trial B r u n o M o r g a n a, *, A n d r e w R. J o n e s a, Kevin A. M u l c a h y a D a v i d B. Finlay a and B e v e r l y Collett b a Department of Radiology and b Pain Management Clinic, Leicester Royal Infirmary, Infirmary Square, Leicester LE1 5 W W (UK)
(Received 26 January 1995, revisionreceived22 March 1995, accepted 10 May 1995)
Summary Transcutaneous electric nerve stimulation (TENS) is a safe and simple form of analgesia but is little used as an adjunct to local anaesthesia during routine procedures. This trial investigates the use of TENS in the radiology department using distension shoulder arthrography for 'frozen shoulder', a moderately painful procedure, as a model. Sixty patients With a clinical diagnosis of 'frozen shoulder' were randomised to receive high-intensity TENS, low-intensity TENS or to act as controls. A standard procedure was then performed. Following the procedure patients completed a visual analogue pain scale. Mean recorded pain levels were lower in the TENS groups with a 50% difference between the high-intensity group and a 38% difference between the low-intensity group as compared to control (difference statistically significant P < 0.01 and P < 0.05, respectively). TENS was well tolerated by patients. The 50% reduction in mean pain levels supports the use of TENS for routine painful procedures.
Key words: Transcutaneous electric nerve stimulation; Adhesive capsulitis; Arthrography
Introduction Distension arthrography for 'frozen shoulder' (adhesive capsulitis) has been found to be an effective therapeutic procedure and is recognised as painful (Hulstyn and Weiss, 1993; Mulcahy et al. 1994). Local anaesthesia is used but is unhelpful when cannulating the inflamed capsule and distending the joint. Transcutaneous electric nerve stimulation (TENS) is a safe and simple form of analgesia showing beneficial results in chronic musculoskeletal pain (Deyo et al. 1990a), dental pain (Ottoson et al. 1981), labour pain (Augustinsson et al. 1977) and post operative pain (Hargreaves and Lander 1989). However, little work has been done to assess its role in routine procedures. Lander and Fowler-Kerry (1993) have shown a small but significant benefit of TENS in venepuncture of children. Rawat et al. (1991) were unable to show any advantage of TENS during biliary lithotripsy. This may reflect an increased
* Corresponding author: Dr. B. Morgan, Department of Radiology,
Leicester Royal Infirmary,InfirmarySquare, Leicester LE1 5WW, UK. Tel.: (44) 1533-541414~ext. 6719; FAX: (44) 1533-586721. SSDI 0304-3959(95)00107-7
efficacy of TENS for superficial rather than deep pain (Smith et al. 1986). Many trials concerning TENS show conflicting results with good subjective patient response without objective measured benefit. This may reflect the difficulties in conducting a blinded, controlled trial with a physical therapy such as TENS. Although pain relief is not a major problem in radiology departments, there are many procedures performed for which a safe adjunct to local anaesthesia would improve patients comfort and be particularly helpful for those anxious about pain. We have designed this trial to investigate the use of TENS for routine procedures in the radiology department using distension shoulder arthrography as a model.
Method Ethical approval was obtained from the Leicester Royal Infirmary ethics committee. Sixty patients with a clinical diagnosis of frozen shoulder referred for distension arthrography were sequentially randomised to receive high-intensity TENS, low-intensity TENS, or to act as controls. Informed consent was obtained from all groups. Age, sex and analgesic medicationswere noted. All patients had the procedure fully explained. The TENS groups had the use of
266 TENS explained. The TENS unit was then attached (Neen Pain M a n a g e m e n t Systems, Suffolk, UK). Two 3 × 3 cm skin electrodes (radiolucent) were then placed either side of the shoulder joint. The frequency level was set to 80 Hz which is in the optimum range (Johnson et al. 1989). The high-intensity TENS group had the amplitude of stimulation slowly increased until muscle fasciculation or discomfort occurred. The unit was then adjusted to the m a x i m u m comfortable level. In the low-intensity group the unit was set to a constant level just above the sensory threshold. The TENS unit was allowed to function for 20 min before the procedure, allowing optimum efficacy (Johnson et al. 1989), while control radiographs were taken. A standard procedure was performed by one of the authors (D.F.). The skin and soft tissues were infiltrated with 2 - 3 ml of 1% lignocaine. The shoulder joint was then cannulated with a 22-ga spinal needle u n d e r fluoroscopic control. Iopamidol (5-10 ml), 1 ml of 1% lignocaine and 40 mg of triamcinolone acetate were introduced and the shoulder was distended with 20-30 ml of air. Although we were unable to blind the operator to the control group the 2 TENS groups were double-blinded. After the procedure the TENS unit was removed and the patients were asked to fill in a 100-mm visual analogue pain scale (VAS) regarding the pain of the procedure with one end representing no pain, the other the most severe pain imaginable (Huskinsson 1974; Gilbert et al. 1986). T h e operator was not involved in the administration of the pain questionnaire. The arm was then manipulated and further radiographs taken. The results were analysed for statistical significance using the Wilcoxon rank-sum method.
PATTERN OF PAIN LEVELS BETWEEN THE HIGH INTENSITY TENS GROUP AND CONTROL
6
==4 uJ
1 TENS
i
I[]CONTROLI
3 2
o
o
o
~
~
~
~
~
~
PAIN LEVEL (mm o n V.A.S scale)
Fig. 1.
was well received by patients. Fig. 1 demonstrates the pattern of recorded pain levels between the high-intensity TENS group and the control group. It can be seen that no patients in the TENS group recorded pain levels in the top half of the pain scale.
Results
The results are shown in Table I. The patients in the 3 groups were comparable for age and sex. Two patients in the high-intensity group and 1 patient in the low-intensity group had taken paracetamol in the 6 h prior to the procedure. Two patients in the control group had taken ibuprofen in the 6 h prior. Their subsequent pain levels were not substantially different from the mean pain levels in their groups. No other analgesic medication had been taken. Mean recorded pain levels show a 50% difference in the high-intensity group and a 38% difference in the low-intensity group as compared to control. These differences are statistically significant by the Wilcoxon rank-sum method (P < 0.01 and P < 0.05, respectively). The 20% difference in mean pain levels between the high- and low-intensity group does not reach statistical significance. No problems were associated with the use of TENS which
TABLE I PAIN LEVELS R E C O R D E D IN T R I A L G R O U P S Group
High-intensity TENS Low-intensity TENS Control
Number Age (years) Sex ( M \ F ) VAS
20 44.5 (SD + 13) 10\10 19 (SD + 15.5) a
20 44.5 (SD + 11) 10\10 23.5 (SD + 20) b
20 45 (SD + 15) 8\12 37.5 (SD + 25)
VAS, m e a n recorded pain level on VAS ( \ I 0 0 mm). a Difference from control statistically significant ( P < 0.01). b Difference from control statistically significant ( P < 0.05).
Discussion
The design of trials for physical therapies can often be criticised as it is impossible to fully blind the study and use adequate placebo controls. In the case of TENS there is no placebo equivalent of sensory stimulation. Deyo et al. (1990b) showed that greater than 40% of patients in a sham TENS group (TENS unit switched on with red light showing but with no output) were not convinced that their TENS unit was functioning. This is the method used by most trials concerning TENS. Furthermore the control group cannot be blinded from the operator as the use of TENS is difficult to disguise. For this reason we did not use sham TENS but 2 groups with functioning TENS. This avoids the problem of an inadequate placebo group but makes it more difficult to separate a real from placebo effect. The high-intensity group is operated at the maximum comfortable level which has been shown to be its optimum setting (Johnson et al. 1989; Leandri et al. 1990). The low-intensity group is operated at just above the sensory threshold. Although TENS at this level has less activity than at higher settings some effect was expected. One study has suggested that even sub-threshold TENS has some effect (Lehmann et al. 1986). The results show the hypothesised pattern of reduced pain levels with increasing TENS stimulation although the difference between the high- and low-intensity groups does not reach statistical significance making a placebo effect for both groups a possibility.
267
The use of high-intensity TENS was also associated with no patients recording pain levels in the top half of the pain scale. Although applying the TENS unit and allowing time for maximum efficacy may be time-consuming, the 50% differertce in pain levels between the high-intensity TENS group and control, along with the high patient satisfaction with TENS, support a role for its use in routine procedures.
References Augustinsson, L.E., Bohlin, P., and Bundsen, P., Pain relief during delivery by transcutaneous electric nerve stimulation (TENS), Pain, 4 (1977) 59-65. Deyo, R.A., Walsh, N.E., Martin, D.C., Schoenfield, L.S., and Ramamurthy S.A., A controlled trial of transcutaneous electric nerve stimulation (TENS) and exercise in chronic low back pain, N. Engl. J. Med., 322 (1990a) 1627-1634. Deyo, R.A., Waish, N.E., Schoenfeld, L.S., and Ramamurthy, S., Can trials of physical treatments be blinded. The example of transcutaneous electric nerve stimulation for chronic pain. Am. J. Phys. Med. Rehab., 69 (1990b) 6-10. Gilbert, J.M., Gledhill, T., Law, N., and George, C., Controlled trial of transcutaneous electric nerve stimulation (TENS) for post operative pain relief following inguinal herniorrhaphy. Br. J. Surg., 73 (1986) 749-751. Hargreaves, A., and Lander, J.. Use of transcutaneous electric nerve
stimulation (TENS) for postoperative pain. Nurs. Res., 38 (1989) 159-161. Hulstyn, M.J., and Weiss, A.P., Adhesive capsulitis of the shoulder. Orthop. Rev., 22 (1993) 425-433. Huskinsson, E.C., Measurement of pain, Lancet, ii (1974) 1127-1131. Johnson, M.I., Ashton, C.H., Bousfield, D.R., and Thompson, J.S., Analgesic effects of different frequencies of transcutaneous electric nerve stimulation on cold induced pain in normal subjects, Pain, 39 (1989) 231-236. Lander, J., and Fowler-Kerry, S., Transcutaneous electric nerve stimulation (TENS) for children's procedural pain, Pain, 52 (1993) 209-216. Leandri, M., Parodi, C.I., Corrieri, N., and Rigardo, S., Comparison of transcutaneous electric nerve stimulation treatments in hemiplegic shoulder pain. Scand. J. Rehab. Med., 22 (1990) 69-71. Lehmann, T.R., Russell, D.W., and Spratt, K.F., Efficacy of electroacupuncture and transcutaneous electric nerve stimulation in the rehabilitation of chronic low back pain patients, Pain, 26 (1986) 277-290. Mulcahy, K.A., Baxter, A.D., Oni, O.O.A., and Finlay, D.B., The value of shoulder distension arthrography with intra-articular injection of steroid and local anaesthesia: a follow up study. Br. J. Radiol., 67 (1994) 263-266. Ottoson, D., Ekblom, A., and Hansson, P., Vibratory stimulation for the relief of pain of dental origin, Pain, 10 (1981) 37-45. Rawat, B., Genz, A., Fache, J.S., Ong, N.Y., Coldman, A.J., and Burhenne, H.J., Effectiveness of transcutaneous electric nerve stimulation (TENS) for analgesia during biliary lithotripsy. Invest. Radiol., 26 (1991) 866-869. Smith, C.M., Guralnick, M.S., Gelfand, M.M., and Jeans, M.E. The effect of transcutaneous electric nerve stimulation (TENS) on post caesarean pain, Pain, 27 (1986) 181-193.