**1. Introduction**

Spinal pain is a growing concern in aging populations with increasing life expectancy worldwide. Degenerative lumbar spinal stenosis (LSS) frequently causes typical symptoms, including neurologic intermittent claudication, sciatica and low back pain. In addition, vague leg symptoms, such as paresthesia, weakness and altered sensation, may exist [1,2]. These characteristic manifestations may lead to functional disabilities in activities of daily living (ADL), decreased quality of life and increased social isolation, especially in older adults.

Functional disability in ADL may be a representative of the disease severity of LSS, because it means how the spinal pain and neurologic deficit affects the patients' daily life. It has been reported that the greater the intensity of symptoms, the worse the functional disability [3]. Furthermore, evaluating functional disability in ADL may help to establish the treatment plan and even predict the post-surgical outcome for patients with LSS [4]. Radiologic imaging, such as magnetic resonance imaging (MRI), is used to decide the severity of LSS with more clarity, but it is greatly limited. It is well known that the correlation between the functional status and the severity of radiologic findings is often unmatched [5,6]. Despite the importance of functional disability in ADL in LSS patients, there are no clear predictive factors associated with it.

Obesity has been increasingly investigated as a potential predictor for the development of various lumbar spinal disorders, but the results are inconsistent, and the causal

**Citation:** Kim, Y.; Lee, C.; Oh, H.; Son, J.-S.; Doo, A. The Effects of Body Composition Characteristics on the Functional Disability in Patients with Degenerative Lumbar Spinal Stenosis. *J. Clin. Med.* **2023**, *12*, 612. https:// doi.org/10.3390/jcm12020612

Academic Editor: Misao Nishikawa

Received: 20 December 2022 Revised: 2 January 2023 Accepted: 6 January 2023 Published: 12 January 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

relationships are also unclear [7–13]. Several researches suggested that obese patients were at a higher risk of developing lumbar spinal disorder, including LSS, compared to normal-weight individuals [10,11]. Other studies reported that obesity was associated with the severity of the lumbar intervertebral disc degeneration and even with the less functional improvement after surgery in LSS patients [8,14,15]. However, there are few investigations of how obesity (increased body fat) affects functional disability in ADL in patients who were diagnosed with LSS.

The aim of the current study was to determine if an association exists between body composition characteristics and functional disability in ADL of LSS patients, especially to understand which body fat parameters could accurately predict it. We further expected that other body composition parameters related to the amount of skeletal muscle also affect it. Additionally, the therapeutic effects of epidural steroid injection of LSS patients were evaluated.
