Observed patterns of cervical radiculopathy: how often do they differ from a standard, “Netter diagram” distribution?

Abstract

BACKGROUND CONTEXTTraditionally, cervical radiculopathy is thought to present with symptoms and signs in a standard, textbook, reproducible pattern as seen in a “Netter diagram.” To date, no study has directly examined cervical radicular patterns attributable to single level pathology in patients undergoing ACDF. PURPOSEThe purpose of this study is to examine cervical radiculopathy patterns in a surgical population and determine how often patients present with the standard textbook (ie, Netter diagram) versus nonstandard patterns. STUDY DESIGN/SETTINGA retrospective study. PATIENT SAMPLEPatients who had single-level radiculopathy with at least 75% improvement of preoperative symptoms following ACDF were included. OUTCOME MEASURESEpidemiologic variables were collected including age, sex, weight, body mass index, laterality of symptoms, duration of symptoms prior to operative intervention, and the presence of diabetes mellitus. The observed pattern of radiculopathy at presentation, including associated neck, shoulder, upper arm, forearm, and hand pain and/or numbness, was determined from chart review and patient-derived pain diagrams. METHODSWe identified all patients with single level cervical radiculopathy operated on between March 2011 and March 2016 by six surgeons. The observed pattern of radiculopathy was compared to a standard textbook pattern of radiculopathy that strictly adheres to a dermatomal map Fisher exact test was used to analyze categorical data and Student t test was used for continuous variables. A one-way ANOVA was used to determine differences in the observed versus expected radicular pattern. A logistic regression model assessed the effect of demographic variables on presentation with a nonstandard radicular pattern. RESULTSOverall, 239 cervical levels were identified. The observed pattern of pain and numbness followed the standard pattern in only 54% (129 of 239; p=.35). When a nonstandard radicular pattern was present, it differed by 1.68 dermatomal levels from the standard (p<.0001). Neck pain on the radiculopathy side was the most prevalent symptom; it was found in 81% (193 of 239) of patients and did not differ by cervical level (p=.72). In a logistic regression model, none of the demographic variables of interest were found to significantly impact the likelihood of presenting with a nonstandard radicular pattern. CONCLUSIONSObserved patterns of cervical radiculopathy only followed the standard pattern in 54% of patients and did not differ by the cervical level involved. Cervical radiculopathy often presents with a nonstandard pattern. Surgeons should think broadly when identifying causative levels because they frequently may not adhere to textbook descriptions in actual clinical practice. We observed III level of evidence.