153 – THE RELIABILITY OF DIFFERENTIATING NEUROGENIC CLAUDICATION FROM VASCULAR CLAUDICATION BASED ON SYMPTOMATIC PRESENTATION

Abstract

Purpose: Claudication is a common complaint of elderly patients. Lumbar spinal stenosis (LSS) and peripheral arterial disease (PAD) are the two main etiologies, producing neurogenic and vascular claudication respectively. Physicians initially diagnose claudication based on a “typical” symptom profile. The reliability of this symptom profile to accurately diagnose LSS or PAD as a cause of claudication is unknown, leading to the potentially unnecessary utilization of expensive and overly sensitive imaging modalities. Furthermore, clinicians rely on this symptom profile when directing treatment for patients with concurrent imaging positive for LSS and PAD. This study evaluates the reliability of various symptom attributes, which classically have characterized and differentiated the two.

Method: Patients presenting at a tertiary care center’s vascular or spine clinics with a primary complaint of claudication were enrolled in the study. Diagnosis of either LSS or PAD was confirmed with imaging for each patient. They answered 14 questions characterizing their symptoms. Sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR) was determined for each symptom attribute.

Results: The most sensitive symptom attribute to rule out LSS is “triggering of pain with standing alone” (0.96). Four symptom attributes demonstrated a high PLR and three had low NLR for diagnosing neurogenic claudication (PLR= 3.08, 2.51, 2.14, 2.9; NLR=0.06, 0.29, 0.15). In vascular patients, calf symptoms and alleviation of pain with simply standing had a high PLR and NLR (PLR= 3.08 and 4.85; NLR= 0.31 and 0.36).

Conclusion: Only four of 14 “classic” symptom attributes are highly sensitive for ruling out LSS, and should be considered by primary care physicians before pursing expensive diagnostic imaging. Six symptom attributes should be relied upon to differentiate LSS and NLR. Numbness, pain triggered with standing alone, located in the buttock and thigh, and relieved following sitting, are symptom attributes which reliably characterize neurogenic claudication.