Clinical predictors of surgical outcomes of severe carpal tunnel syndrome patients: utility of palmar stimulation in a nerve conduction study

Abstract

Background Carpal tunnel syndrome is a common peripheral nerve compression disorder. However, there is no established opinion regarding the predictors of symptom improvement after surgery. This study aimed to identify the predictors of surgical outcomes of severe carpal tunnel syndrome patients. Methods In the patients who underwent a carpal tunnel syndrome surgery, we selected the patients who had a preoperative Bland’s classification of grade 5 or 6, and assessed for the changes in Bland’s classification grade before and after surgery. Those who showed improvement from preoperative grades 5–6 to postoperative grades 1–4 comprised the improvement group. In contrast, those who did not show improvement and had postoperative grades 5 or 6 comprised the non-improvement group. In a nerve conduction study, amplitudes of the compound muscle action potential and sensory nerve action potential of the palms were assessed between the improvement and non-improvement groups. Results Among the 60 hands of 46 patients who had a preoperative Bland’s classification of grade 5 or 6, 49 hands of 37 patients comprised the improvement group, and 11 hands of 9 patients comprised the non-improvement group. The amplitudes of the compound muscle action potential and sensory nerve action potential of the palms before surgery were significantly higher in the improvement group. The degree of improvement in Bland’s classification grade was correlated with the degree of clinical symptom improvement. Conclusions Amplitudes of compound muscle action potential and sensory nerve action potential before surgery induced by palmar stimulation can predict improvements in nerve conduction study scores and clinical findings after surgical treatment.

The Relevance of Collision Tests and Quantitative Sensory Testing in Diagnostics and Postoperative Outcome Prediction in Carpal Tunnel Syndrome

“…The risk of no improvement was very small (3%) for stage 2 on the Hi-Ob scale, and nearly 96% in stage 4 in the logistic regression modeling for CTS severity. Some other studies have shown similar results for post-operative predictors ( 9 , 13 , 38 – 40 ). In contrast, van der Broeke et al ( 22 ) did not confirm the dependence of treatment results on the initial severity and duration of CTS.…”

Evaluation of the Existing Electrophysiological Severity Classifications in Carpal Tunnel Syndrome

“…Median nerve conduction studies in CTS cases evaluate both sensory and motor nerve fibers. Electrophysiological severity classification in CTS is a useful method to show these evaluation parameters on a single scale [ 11 , 12 ], and there are many reports on clinical evaluations using severity classifications [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. However, as shown in this paper, the existing severity classifications do not always accurately reflect the severity of disease, and our results suggest the need to reevaluate previous studies that used these classifications.…”

Opponensplasty using the extensor indicis proprius tendon for severe carpal tunnel syndrome in 40 patients

“…Moreover, it is difficult to determine the amount of opposition strength achieved from the tendon transfer and whether the opposition strength is a result of spontaneous thenar muscle recovery. As APB atrophy can be caused by a decreased number of axonal fibres at the level of the recurrent motor branch (Sasaki et al, 2020), the measurement of CMAP-APB amplitudes by median nerve stimulation at the wrist, which are indicators of the remaining axons in the thenar muscles, will be useful in evaluating the spontaneous recovery of the thenar muscles. In our series, the mean DML of the APB was 5.9 ms, while the mean CMAP-APB amplitude was 1.1 mV at final follow-up.…”