Surgeon Ratings of the Severity of Idiopathic Median Neuropathy at the Carpal Tunnel Are Not Influenced by Magnitude of Incapability

Abstract

Background: Accurately distinguishing the severity of pathophysiology from the level of symptom intensity and incapability is a foundation of effective treatment strategies under the biopsychosocial paradigm of illness. With respect to idiopathic median neuropathy at the carpal tunnel (the symptoms and signs of which are referred to as carpal tunnel syndrome), surgeons who are more likely to recommend surgery based on the magnitude of symptoms and incapability rather than the severity of neuropathy may be underappreciating and undertreating mental health opportunities and overtreating mild, and on occasion unmeasurable, disease. A survey-based experiment that randomizes elements of the patient presentation can help determine the relative influence of magnitude of incapability on ratings of pathology severity.

Question/purpose: What factors are associated with severity rating of idiopathic median neuropathy at the carpal tunnel on an 11-point ordinal scale?

Methods: One hundred eight hand and wrist members of the Science of Variation Group (among approximately 200 participants who complete at least one survey-experiment a year related to the upper extremity on average) reviewed seven scenarios of fictional median neuropathy with seven randomized variables: age, gender, limitations of daily activity (incapability), Tinel and Phalen test results, duration of numbness episodes, prevention of numbness with nocturnal splint immobilization, constant numbness, and weakness of palmar abduction. Participants had a mean age of 51 ± 10 years, 90% (97 of 108) were men, and 74% (80 of 108) were subspecialized in hand surgery. Surgeons were asked to rate the severity of idiopathic median neuropathy at the carpal tunnel on a on an 11-point ordinal scale. Factors associated with rated severity were sought in multilevel ordered logistic regression models. Fifteen surgeons did not complete all of their assigned randomized scenarios, resulting in a total of 675 ratings.

Results: After controlling for potentially confounding variables such as magnitude of incapability, factors associated with severity rating on the 11-point ordinal scale included palmar abduction weakness (odds ratio 11 [95% confidence interval 7.7 to 15]), longer duration of symptom episodes (OR 4.5 [95% CI 3.3 to 6.2]), nocturnal numbness in spite of splint immobilization (OR 3.2 [95% CI 2.3 to 4.3]), constant numbness (OR 2.5 [95% CI 1.9 to 3.4]), positive Tinel and positive Phalen test results (OR 2.2 [95% CI 1.6 to 2.9]), and older age (OR 1.6 [95% CI 1.2 to 2.1]).

Conclusion: Our results suggest that surgeons rate the severity of idiopathic median neuropathy at the carpal tunnel based on evidence of worse pathophysiology and are not distracted by greater incapability.

Clinical relevance: Surgeons who consider greater incapability as an indication of more severe pathology seem to be practicing outside the norm and may be underappreciating and undertreating the unhelpful thoughts and feelings of worry or despair that consistently account for a notable amount of the variation in symptom intensity and magnitude of incapability.