NERVE
CONDUCTION FOR CARPAL
STUDIES TUNNEL
AFTER TREATMENT SYNDROME
P. SEROR
From the Laboratory for Electromyography, Paris
125 cases of carpal tunnel syndrome confirmed electrophysiologically were the subject of longitudinal nerve conduction studies to assess spontaneous improvement and effect of treatment. 36 cases showed a slowly progressive deterioration which became stastistically significant only on lengthy follow-up; analysis of interval tests in these cases revealed that definite improvement or rapid worsening can occur in the interim. The 56 cases studied after local corticosteroid injections showed a statistically significant improvement at one month followed by an overall progressive return to the previous abnormal values in six to 12 months, indicating only slight aud temporary alteration in the natural progression of the conduction deficit. The 33 cases which underwent surgical release of the median nerve were shorn to have obvious and often raDid imurovement, which was sustained for at least one year after surgery. Journal of Hand Skgery (B&h Volume, 1992) 1;7B: 641-645 -
Reports of nerve conduction studies following treatment for carpal tunnel syndrome are uncommon. There are no studies in which one laboratory using the same standardized techniques has performed a longitudinal study of untreated patients and those treated by local corticosteroid injection or surgery. Simpson (1956) first demonstrated alterations in median nerve conduction at the wrist and showed that surgical treatment not only improved the symptoms but also decreased electrophysiological abnormalities. A later study by Goodman and Gilliatt (1961) compared the results of surgical treatment in 23 cases of carpal tunnel syndrome with 25 cases treated by splintage. Goodman and Foster (1962) reported on treatment by injections into the carpal tunnel. Finally, studies of steroid injection have been reported by Gelberman et al. (1980) and by Ozdagan and Yazici (1984), and Magalon et al. (1982) described the results of experimental work on the action of corticosteroid on nerve fibres.
MATERIAL
One to three injections of corticosteroid were administered into the carpal tunnels of 56 patients: 41 were followed up one month after injection (group II.l), 26 between four and 29 months (group 11.2) and 11 were reexamined twice at one month and three to eight months later (group 11.3). 33 wrists underwent surgery either following no response to corticosteroid injection or because of the severity of symptoms and of findings on initial nerve conduction studies. 18 patients were followed up two months after surgical release (group III.l), 24 were followed up between four and 30 months after surgical release (group 111.2) and nine were seen twice at two months and five to 12 months later (group 111.3).
Electrophysiological method The initial examination was designed to confirm the involvement of the median nerve at the wrist and to eliminate other possible aetiological factors such as brachial plexus compression, cervical root lesion or anterior horn cell involvement. The nerve conduction study also included bilateral evaluation of the motor and sensory conduction velocity of the median and ulnar nerves at arm, forearm, and wrist with a surface electrode, and evaluation of the recruitment pattern with needle electrodes (Seror, 1987) in C5 to Tl myotomes. Follow-up involved measurement of the distal motor latency and the orthodromic sensory conduction velocity with palmar stimulation. The amplitude of both motor and sensory action potentials was recorded. Needle examination was rarely used at follow-up in order to avoid unnecessary discomfort and to obtain better patient compliance with testing. This paper reports the results of sensory conduction velocity data rather than motor conduction velocity and residual latency because of greater reproducibility, and
AND METHODS
Patients 125 wrists with carpal tunnel syndrome as defined by current electrophysiological criteria (Buchtal et al., 1974; Seror, 1987) were examined in one laboratory. The cases were divided into three groups depending upon the method of treatment. 36 of the wrists received no local treatment but they may have benefitted from generalized effects of local corticosteroid injection into the opposite wrist, or from administration of oral anti-inflammatory or vascular drugs. These cases were not followed up at any fixed date; group I.1 were re-examined after l-23 months, group I.2 after 24-52 months. 641
642
THE JOURNAL
the even distribution (Seror et al., 1988).
of sensory conduction
velocity
OF HAND SURGERY
VOL. 17B No. 6 DECEMBER
92
group and surgical group (Table l), but this data was excluded from determination of variation in sensory conduction velocity at follow-up.
Statistical method
Changes in sensory conduction velocity at the wrist were analysed by the Mann-Whitney and Student’s tests. For this comparison the data were split up by treatment type and length of follow-up time into eight groups: two untreated, three treated by injection and three treated by surgery. Each of these eight groups was compared with three separate reference groups; (1) a “null reference” group with no change in nerve conduction status; (2) the medium-term untreated cases (group I.l), and (3) the long-term corticosteroid injection cases (group 11.2).
RESULTS
Follow-up findings
The results of the sensory conduction velocity follow-up are shown graphically in Figures 1, 2 and 3 and numerically in Table 2. Only results and statistical data with the “null reference” are reported in the text, other reference results are in Table 2. No treatment (Fig. 1, Table 2) Group I (groups I.1 and 1.2): the 36 untreated wrists show a mean reduction in the sensory conduction velocity equal to2.73 m/secf7.3 (P>O.O5; t= 1.87). The worsening increases with time, being - 1.5 m/set after 8 months and - 6.4 m/set after 33 months (P< 0.03 ; t = 2.6).
Epidemiological findings
Corticosteroid injection (Fig. 2, Table 2)
These are summarized in Table 1. They are comparable as regards age, gender and duration of symptoms. The initial investigation showed a difference (P< 0.05) in sensory conduction velocity in the three groups, with the untreated group being the least affected and the operated group the most severe. This is explained by two facts: patients with severe nerve compression at initial electrophysiological examination and those who had multiple corticosteroid injections underwent surgery; the untreated wrists were the opposite of the treated ones (groups II and III) and were usually milder electrophysiologically. In six subjects with severe carpal tunnel syndrome, five treated by surgery and by steroid injection, sensory conduction velocity could not be obtained initially, and an arbitrary value (sensory conduction velocity = 20 m/set) was assigned to these subjects. This magnified the statistical difference between the injection
Group II.1 : sensory conduction velocity increased only +2.5 m/set (PC 10M5;t-4.7) in this group. The change was positive in 28 cases, negative in six and no change in seven (Table 2, group II. 1). Group 11.2: the change in mid-term varied considerably in this group, being negative in eight cases, no change in two and positive in 15. Most of the cases (20) showed little variation in amplitude (less than 8 m/set) and large positive or negative variations in amplitude occurred in only six cases. After excluding the six cases, the mean variation in this group was 0.26 m/set + 3.8. Group 11.3: 11 wrists underwent follow-up at one month and again in the interval between three and eight months. Worsening of sensory conduction velocity in this group was equal to - 2.2 m/set. The change was positive in three cases, negative in seven and there was no change in one.
Table l-Initial
epidemiologiccal findings
Without treatment Age ii~ > 70 years
Sex M F Duration
(months)
SCV fi (mjsec) Number with carpal tunnel syndrome
Steroid injection
STAT
STAT
Surgery
57.6 (28-87)
58.6 (28-87)
20%
18%
57.5 (30-88) 19%
21%
79%
19% 81%
24% 76%
20.9
22.9
23.3
39.6+
10.3
Non-significant
36
STAT: Statistical analysis (Student test). *sensory conduction velocity not obtained; equivalent to sensory conduction velocity= 20 m/set.
*36.6+8.3 56 (l*)
P 8 mjsec) for a period of less than 12 months in an unpredictable way in 20% of the cases. Injection gives some statistically significant improvement in carpal tunnel syndrome in the first one to two months. Surgical treatment is reliably effective. The improvement at two months represents 66% of that at one year. This is in spite of the fact that those treated surgically have more severe compression pre-operatively than the other groups.
645
Acknowledgement Very sincere acknowledgements the translation.
to Peter Nathan,
MD, who kindly helped with
References BUCHTAL, F., ROSENFALK, A. and TROJABORG, W. (1974). Electrophysiological findings in entrapment of the median nerve at wrist and elbow. Journal of Neurology, Neurosurgery and Psychiatry, 37: 340-360. GELBERMAN, R. H., ARONSON, D. and WEISMAN, M. H. (1980). Carpaltunnel syndrome: results of a prospective trial of steroid injection and splinting. Journal of Bone and Joint Surgery, 62A: 1181-l 184. GOODMAN, H. V. and FOSTER, J. B. (1962). Effect of local corticosteroid injection on median nerve conduction in carpal tunnel syndrome. Annals of Physical Medicine and Rehabilitation, 6: 287-294. GOODMAN, H. V. and GILLIATT, R. W. (1961). The effect of the treatment on median nerve conduction in patients with the carpal tunnel syndrome. Annals of Physical Medicine and Rehabilitaton, 6: 137-155. HARRIS, C. M., TANNER, E., GOLDSTEIN, M. N. and PETTEE, D. S. (1979). The surgical treatment of the carpal-tunnel syndrome correlated with preoperative nerve-conduction studies. Journal of Bone and Joint Surgery, 61A: 93-98. HONGELL, A. and MATTSSON, H. S. (1971). Neurographic studies before, after, and during operation for median nerve compression in the carpal tunnel. Scandinavian Journal of Plastic and Reconstructive Surgery, 5: 103109. LECLAIRE, R. and PROVOST, S. (1980). Syndrome du canal carpien: Etude sur les r6sultats cliniques et Blectrodiagnostiques post-neurolyse carpienne. L’Union Medicale du Canada, 109: 82-89. MAGALON, G., ROFFE, J. L., PELISSIER, J. F., CHRESTIAN, M., BENAIM, L. and BUREAU, H. (1982). Action des corticdides locaux surla fibre nerveuse: Etude expirimentale. Semaine des HBpitaux de Paris, 19: 1173-1178. MARIE, P. and FOIX (1913). Atrophie isolee de l’lminence th6nar d’origine nbvritique. RBle du ligament annulaire antkrieur du carpe dans la pathog6nie de la l&ion. Revue de Neurologie, 21: 647-649. OZDAGAN, H. and YAZICI, H. (1984). The efficacy of local steroid injections in idiopathic carpal tunnel syndrome: a double blind study. British Journal of Rheumatology, 23 : 272-275. RHOADES, C. E., MOWERY, C. A. and GELBERMAN, R. H. (1985). Results of internal neurolysis of the median nerve for severe carpal-tunnel syndrome. Journal of Bone and Joint Surgery, 67A: 2: 253-256. ROFFE, J. L., MAGALON, G., DECAILLET, J. M., LATIL, F. andBUREAU, H. (1981). Le syndrome du canal carpien: aspects ktiologiques et thbrapeutiques actuels: 250 malades op&r&s et revus. La Nouvelle Presse Mkdicale, 10: 1205-1209. SEROR, P., BECTARTE, M. and MORTIER, J. P. (1988). Syndrome du canal carpien: aspects Blectrophysiologiques de l’kvolution naturelle et apr& traitement. Revue de Chirurgie OrthopBdique, 74: 466472. SEROR, P. (1987). A la recherche d’une corrtlation Blectro-clinique au cows du syndrome du canal carpien: apropos de 100 cas. Revue du Rhumatisme, 54: 10 : 643-648. SEROR, P. (1990). Le syndrome du canal carpien chez le sujet de plus de 70 ans. La Presse Mbdicale, 19: 1371. SIMPSON, J. A. (1956). Electrical signs in the diagnosis of carpal tunnel and related syndromes. Journal of Neurology, Neurosurgery and Psychiatry, 19: 275-280.
Accepted: I November 1991 Dr P. Seror, Laboratoire dBlectromyographie, 148 Avenue Parmentier, 75011 Paris, France. 0 1992 The British Society for Surgery of the Hand
CONDUCTION FOR CARPAL
STUDIES TUNNEL
AFTER TREATMENT SYNDROME
P. SEROR
From the Laboratory for Electromyography, Paris
125 cases of carpal tunnel syndrome confirmed electrophysiologically were the subject of longitudinal nerve conduction studies to assess spontaneous improvement and effect of treatment. 36 cases showed a slowly progressive deterioration which became stastistically significant only on lengthy follow-up; analysis of interval tests in these cases revealed that definite improvement or rapid worsening can occur in the interim. The 56 cases studied after local corticosteroid injections showed a statistically significant improvement at one month followed by an overall progressive return to the previous abnormal values in six to 12 months, indicating only slight aud temporary alteration in the natural progression of the conduction deficit. The 33 cases which underwent surgical release of the median nerve were shorn to have obvious and often raDid imurovement, which was sustained for at least one year after surgery. Journal of Hand Skgery (B&h Volume, 1992) 1;7B: 641-645 -
Reports of nerve conduction studies following treatment for carpal tunnel syndrome are uncommon. There are no studies in which one laboratory using the same standardized techniques has performed a longitudinal study of untreated patients and those treated by local corticosteroid injection or surgery. Simpson (1956) first demonstrated alterations in median nerve conduction at the wrist and showed that surgical treatment not only improved the symptoms but also decreased electrophysiological abnormalities. A later study by Goodman and Gilliatt (1961) compared the results of surgical treatment in 23 cases of carpal tunnel syndrome with 25 cases treated by splintage. Goodman and Foster (1962) reported on treatment by injections into the carpal tunnel. Finally, studies of steroid injection have been reported by Gelberman et al. (1980) and by Ozdagan and Yazici (1984), and Magalon et al. (1982) described the results of experimental work on the action of corticosteroid on nerve fibres.
MATERIAL
One to three injections of corticosteroid were administered into the carpal tunnels of 56 patients: 41 were followed up one month after injection (group II.l), 26 between four and 29 months (group 11.2) and 11 were reexamined twice at one month and three to eight months later (group 11.3). 33 wrists underwent surgery either following no response to corticosteroid injection or because of the severity of symptoms and of findings on initial nerve conduction studies. 18 patients were followed up two months after surgical release (group III.l), 24 were followed up between four and 30 months after surgical release (group 111.2) and nine were seen twice at two months and five to 12 months later (group 111.3).
Electrophysiological method The initial examination was designed to confirm the involvement of the median nerve at the wrist and to eliminate other possible aetiological factors such as brachial plexus compression, cervical root lesion or anterior horn cell involvement. The nerve conduction study also included bilateral evaluation of the motor and sensory conduction velocity of the median and ulnar nerves at arm, forearm, and wrist with a surface electrode, and evaluation of the recruitment pattern with needle electrodes (Seror, 1987) in C5 to Tl myotomes. Follow-up involved measurement of the distal motor latency and the orthodromic sensory conduction velocity with palmar stimulation. The amplitude of both motor and sensory action potentials was recorded. Needle examination was rarely used at follow-up in order to avoid unnecessary discomfort and to obtain better patient compliance with testing. This paper reports the results of sensory conduction velocity data rather than motor conduction velocity and residual latency because of greater reproducibility, and
AND METHODS
Patients 125 wrists with carpal tunnel syndrome as defined by current electrophysiological criteria (Buchtal et al., 1974; Seror, 1987) were examined in one laboratory. The cases were divided into three groups depending upon the method of treatment. 36 of the wrists received no local treatment but they may have benefitted from generalized effects of local corticosteroid injection into the opposite wrist, or from administration of oral anti-inflammatory or vascular drugs. These cases were not followed up at any fixed date; group I.1 were re-examined after l-23 months, group I.2 after 24-52 months. 641
642
THE JOURNAL
the even distribution (Seror et al., 1988).
of sensory conduction
velocity
OF HAND SURGERY
VOL. 17B No. 6 DECEMBER
92
group and surgical group (Table l), but this data was excluded from determination of variation in sensory conduction velocity at follow-up.
Statistical method
Changes in sensory conduction velocity at the wrist were analysed by the Mann-Whitney and Student’s tests. For this comparison the data were split up by treatment type and length of follow-up time into eight groups: two untreated, three treated by injection and three treated by surgery. Each of these eight groups was compared with three separate reference groups; (1) a “null reference” group with no change in nerve conduction status; (2) the medium-term untreated cases (group I.l), and (3) the long-term corticosteroid injection cases (group 11.2).
RESULTS
Follow-up findings
The results of the sensory conduction velocity follow-up are shown graphically in Figures 1, 2 and 3 and numerically in Table 2. Only results and statistical data with the “null reference” are reported in the text, other reference results are in Table 2. No treatment (Fig. 1, Table 2) Group I (groups I.1 and 1.2): the 36 untreated wrists show a mean reduction in the sensory conduction velocity equal to2.73 m/secf7.3 (P>O.O5; t= 1.87). The worsening increases with time, being - 1.5 m/set after 8 months and - 6.4 m/set after 33 months (P< 0.03 ; t = 2.6).
Epidemiological findings
Corticosteroid injection (Fig. 2, Table 2)
These are summarized in Table 1. They are comparable as regards age, gender and duration of symptoms. The initial investigation showed a difference (P< 0.05) in sensory conduction velocity in the three groups, with the untreated group being the least affected and the operated group the most severe. This is explained by two facts: patients with severe nerve compression at initial electrophysiological examination and those who had multiple corticosteroid injections underwent surgery; the untreated wrists were the opposite of the treated ones (groups II and III) and were usually milder electrophysiologically. In six subjects with severe carpal tunnel syndrome, five treated by surgery and by steroid injection, sensory conduction velocity could not be obtained initially, and an arbitrary value (sensory conduction velocity = 20 m/set) was assigned to these subjects. This magnified the statistical difference between the injection
Group II.1 : sensory conduction velocity increased only +2.5 m/set (PC 10M5;t-4.7) in this group. The change was positive in 28 cases, negative in six and no change in seven (Table 2, group II. 1). Group 11.2: the change in mid-term varied considerably in this group, being negative in eight cases, no change in two and positive in 15. Most of the cases (20) showed little variation in amplitude (less than 8 m/set) and large positive or negative variations in amplitude occurred in only six cases. After excluding the six cases, the mean variation in this group was 0.26 m/set + 3.8. Group 11.3: 11 wrists underwent follow-up at one month and again in the interval between three and eight months. Worsening of sensory conduction velocity in this group was equal to - 2.2 m/set. The change was positive in three cases, negative in seven and there was no change in one.
Table l-Initial
epidemiologiccal findings
Without treatment Age ii~ > 70 years
Sex M F Duration
(months)
SCV fi (mjsec) Number with carpal tunnel syndrome
Steroid injection
STAT
STAT
Surgery
57.6 (28-87)
58.6 (28-87)
20%
18%
57.5 (30-88) 19%
21%
79%
19% 81%
24% 76%
20.9
22.9
23.3
39.6+
10.3
Non-significant
36
STAT: Statistical analysis (Student test). *sensory conduction velocity not obtained; equivalent to sensory conduction velocity= 20 m/set.
*36.6+8.3 56 (l*)
P 8 mjsec) for a period of less than 12 months in an unpredictable way in 20% of the cases. Injection gives some statistically significant improvement in carpal tunnel syndrome in the first one to two months. Surgical treatment is reliably effective. The improvement at two months represents 66% of that at one year. This is in spite of the fact that those treated surgically have more severe compression pre-operatively than the other groups.
645
Acknowledgement Very sincere acknowledgements the translation.
to Peter Nathan,
MD, who kindly helped with
References BUCHTAL, F., ROSENFALK, A. and TROJABORG, W. (1974). Electrophysiological findings in entrapment of the median nerve at wrist and elbow. Journal of Neurology, Neurosurgery and Psychiatry, 37: 340-360. GELBERMAN, R. H., ARONSON, D. and WEISMAN, M. H. (1980). Carpaltunnel syndrome: results of a prospective trial of steroid injection and splinting. Journal of Bone and Joint Surgery, 62A: 1181-l 184. GOODMAN, H. V. and FOSTER, J. B. (1962). Effect of local corticosteroid injection on median nerve conduction in carpal tunnel syndrome. Annals of Physical Medicine and Rehabilitation, 6: 287-294. GOODMAN, H. V. and GILLIATT, R. W. (1961). The effect of the treatment on median nerve conduction in patients with the carpal tunnel syndrome. Annals of Physical Medicine and Rehabilitaton, 6: 137-155. HARRIS, C. M., TANNER, E., GOLDSTEIN, M. N. and PETTEE, D. S. (1979). The surgical treatment of the carpal-tunnel syndrome correlated with preoperative nerve-conduction studies. Journal of Bone and Joint Surgery, 61A: 93-98. HONGELL, A. and MATTSSON, H. S. (1971). Neurographic studies before, after, and during operation for median nerve compression in the carpal tunnel. Scandinavian Journal of Plastic and Reconstructive Surgery, 5: 103109. LECLAIRE, R. and PROVOST, S. (1980). Syndrome du canal carpien: Etude sur les r6sultats cliniques et Blectrodiagnostiques post-neurolyse carpienne. L’Union Medicale du Canada, 109: 82-89. MAGALON, G., ROFFE, J. L., PELISSIER, J. F., CHRESTIAN, M., BENAIM, L. and BUREAU, H. (1982). Action des corticdides locaux surla fibre nerveuse: Etude expirimentale. Semaine des HBpitaux de Paris, 19: 1173-1178. MARIE, P. and FOIX (1913). Atrophie isolee de l’lminence th6nar d’origine nbvritique. RBle du ligament annulaire antkrieur du carpe dans la pathog6nie de la l&ion. Revue de Neurologie, 21: 647-649. OZDAGAN, H. and YAZICI, H. (1984). The efficacy of local steroid injections in idiopathic carpal tunnel syndrome: a double blind study. British Journal of Rheumatology, 23 : 272-275. RHOADES, C. E., MOWERY, C. A. and GELBERMAN, R. H. (1985). Results of internal neurolysis of the median nerve for severe carpal-tunnel syndrome. Journal of Bone and Joint Surgery, 67A: 2: 253-256. ROFFE, J. L., MAGALON, G., DECAILLET, J. M., LATIL, F. andBUREAU, H. (1981). Le syndrome du canal carpien: aspects ktiologiques et thbrapeutiques actuels: 250 malades op&r&s et revus. La Nouvelle Presse Mkdicale, 10: 1205-1209. SEROR, P., BECTARTE, M. and MORTIER, J. P. (1988). Syndrome du canal carpien: aspects Blectrophysiologiques de l’kvolution naturelle et apr& traitement. Revue de Chirurgie OrthopBdique, 74: 466472. SEROR, P. (1987). A la recherche d’une corrtlation Blectro-clinique au cows du syndrome du canal carpien: apropos de 100 cas. Revue du Rhumatisme, 54: 10 : 643-648. SEROR, P. (1990). Le syndrome du canal carpien chez le sujet de plus de 70 ans. La Presse Mbdicale, 19: 1371. SIMPSON, J. A. (1956). Electrical signs in the diagnosis of carpal tunnel and related syndromes. Journal of Neurology, Neurosurgery and Psychiatry, 19: 275-280.
Accepted: I November 1991 Dr P. Seror, Laboratoire dBlectromyographie, 148 Avenue Parmentier, 75011 Paris, France. 0 1992 The British Society for Surgery of the Hand
