Lumbosacral Radiculoplexus Neuropathy: Neurologic Outcomes and Survival in a Population-Based Study

Abstract

Objective: To determine whether patients in the community with lumbosacral radiculoplexus neuropathy (LRPN) have milder neuropathy than referral patients, we characterized the outcomes and survival of population-based compared to referral-based LRPN cohorts.

Background: Previously, we found that the incidence of LRPN is 4.16/100,000/y, a frequency greater than other inflammatory neuropathies. The survival of patients with LRPN is uncharacterized.

Methods: Sixty-two episodes in 59 patients with LRPN were identified over 16 years (2000-2015). Clinical findings were compared to previous referral-based LRPN cohorts. Survival data were compared to those of age- and sex-matched controls.

Results: At LRPN diagnosis, median age was 70 years, median Neuropathy Impairment Score (NIS) 22 points, 92% had pain, 95% had weakness, 23% were wheelchair-bound, and median modified Rankin Scale score (mRS) was 3 (range 1-4). At last follow-up, median NIS improved to 17 points (p < 0.001) with 56% having ≥4 points improvement, 16% were wheelchair-bound, and median mRS was 2. Compared to referral-based LRPN cohorts, community patients with LRPN had less impairment, less bilateral disease (37% vs 92%), and less wheelchair usage (23% vs 49%). LRPN survival was 86% at 5 years and 55% at 10 years. Compared to age- and sex-matched controls, patients with LRPN had 76% increased risk of death (p = 0.016). In multivariate analysis, diabetes, age, stroke, chronic kidney disease, peripheral artery disease, and coronary artery disease were significant mortality risk factors but LRPN was not.

Conclusion: LRPN is a painful, paralytic, asymmetric, monophasic, sometimes bilateral pan-plexopathy that improves over time but leaves patients with impairment. Although having LRPN increases mortality, this increase is probably due to comorbidities (diabetes) rather than LRPN itself.

Figure 1. Lumbosacral Plexus MRI Findings

(A) Axial T2-weighted fat-saturated image of the pelvis from a patient with lumbosacral radiculoplexus neuropathy demonstrates mild diffuse enlargement and T2-weighted hyperintensity of the lumbosacral nerves, most notable just proximal to the greater sciatic notch (arrows). These are nonspecific findings that may be associated with nerve inflammation. (B) Axial T2-weighted fat-saturated image of the thighs demonstrates increased intramuscular T2-weighted signal of the left semimembranosus (arrowheads). The left semimembranosus is also mildly atrophic compared to the contralateral thigh on the same image (asterisk). The findings are compatible with denervation change.

Figure 2. Matched Comparison of Neuropathy Impairment Score (NIS) and Modified Rankin Scale Score (mRS) of Community Patients With Lumbosacral Radiculoplexus Neuropathy From Diagnosis to Last Follow-up With Neurologist

(A) NIS. (B) mRS.

Figure 3. Kaplan-Meier Survival Curves

(A) Controls (blue) vs patients with lumbosacral radiculoplexus neuropathy (LRPN) (red). (B) Nondiabetic LRPN (blue) vs diabetic LRPN (red). HR = hazard ratio.