Journal List > Korean J Clin Neurophysiol > v.16(1) > 1084131

Yang, Sung, Park, Lee, Shin, and Park: Clinical and Electrophysiological Changes after Open Carpal Tunnel Release: Preliminary Study of 25 Hands

Abstract

Background:

Electrophysiological study has been known as a useful method to evaluate the therapeutic effect of operation in idiopathic carpal tunnel syndrome (CTS). The purpose of this study was to evaluate the clinical and electrophysiological changes after carpal tunnel release (CTR) compared to the preoperative results.

Methods:

We analyzed the changes of nerve conduction study (NCS) before and after minimal open carpal tunnel release in 18 patients (25 hands) with CTS. Follow-up study was performed over 6 months after operation.

Results:

Clinical improvement was seen in all cases after CTR. In contrast, electrophysiological improvement was various depending on the parameters; the mean median sensory latency and nerve conduction velocity (NCV) improved significantly (p = 0.001). The mean median motor latency also improved, but NCV and compound muscle action potential (CMAP) amplitude did not change. The extent of improvement was evident in moderate CTS, but not in severe CTS.

Conclusions:

In this preliminary study, all subjects who underwent CTR achieved a clinical relief along with a significant improvement of electrophysiological parameters such as median sensory latency, sensory NCV and median distal motor latency. After CTR, a number of cases with mild to moderate CTS showed a prominent improvement of clinical and electrophysiological parameters, while fewer improvements were seen in severe CTS, although it did not reach the statistical significance. (Korean J Clin Neurophysiol 2014;16:21-26)

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Figure 1.
Pre- and post-operative electrophysiological changes in median sensory nerve. A significant improvement was seen in SNCV over F-W segment (A) and over P-W segment (B).
kjcn-16-21f1.tif
Figure 2.
Pre- and post-operative electrophysiological changes in median motor nerve. A significant improvement was seen in DML. SNCV; sensory nerve conduction velocity, F-W; finger-wrist, P-W; palm-wrist, DML; distal motor latency.
kjcn-16-21f2.tif
Table 1.
General characteristics of subjects (Mean±SD; range)
Symptom profile Numbers
Total number of patients (persons) 18
Female 15
Male 3
Total number of CTS (cases) 25
Right side 9
Left side 2
Both side 7
Mean age (years) 57.2±9.8
Mean time between symptoms onset and 1st NCS (months) 15.3±18.8 (1-60)
Mean time to perform follow-up NCS after operation (months) 8.5±7.8 (6-36)
Mean body mass index 23.4±3.8
Post-operative symptoms (cases)
Free 14
>50% improve 11
<50% improve 0

CTS; carpal tunnel syndrome, NCS; nerve conduction study.

Table 2.
Median NCS before and after carpal tunnel release*
Pre-operation Post-operation p-value
Sensory NCS (19 hands)
Sensory latency (ms) 3.7±0.4 (2.9-4.4) 3.1±0.3 (2.6-3.7) 0.001
NCV over F-W segment (m/s) 31.7±4.1 (26.8-39.0) 37.4±3.6 (32.5-46.1) 0.001
NCV over P-W segment (m/s) 27.0±4.3 (20.5-36.3) 33.0±4.3 (27.2-46.1) 0.001
Motor NCS (21 hands)
Motor latency (ms) 5.0±1.2 (3.4-8.3) 3.9±0.5 (2.8-4.9) 0.011
NCV over W-E segment (m/s) 53.3±4.4 (45.4-68.0) 54.2±3.2 (45.2-60.0) 0.385
CMAP amplitude (mV) 10.2±3.2 (4.3-16.1) 11.0±3.0 (5.8-16.4) 0.695

NCS; nerve conduction study, NCV; nerve conduction velocity, F-W; finger-wrist, P-W; palm-wrist, W-E; wrist-elbow, CMAP; compound muscle action potential.

* Values are presented as mean±SD.

Table 3.
Distribution of number of hands in severity of electrophysiological scale at pre- and post-operative NCS
Post-operation All
Normal Mild Moderate Severe
Pre-operation Mild 2 5 - - 7
Moderate 3 5 4 - 12
Severe 0 1 1 4 6
All 5 11 5 4 25

NCS, nerve conduction study.

Table 4.
Relationship between pre-operative electrophysiological severity and post-operative symptom
Electrophysiological severity at pre-operation
Mild Moderate Severe All
Post-operative symptom Free 4 8 2 14
>50% improve 3 4 4 11
<50% improve 0 0 0 0
All 7 12 6 25
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