Visually Assessed Severity of Lumbar Spinal Canal Stenosis Is Paradoxically Associated With Leg Pain and Objective Walking Ability

Pekka Kuittinen; Petri Sipola; Tapani Saari; Timo Juhani Aalto; Sanna Sinikallio; Sakari Savolainen; Heikki Kröger; Veli Turunen; Ville Leinonen; Olavi Airaksinen

Disclosures

BMC Musculoskelet Disord. 2014;15(348)

Background

Lumbar spinal stenosis (LSS) is the term used commonly to describe patients with symptoms related to the anatomical reduction of the size of the lumbar spinal canal.^[1] However, some subjects can have a narrowed canal without presenting any symptoms. Therefore, this peculiarity raised the question of what is the actually role of central canal stenosis in symptomatic patients. The relationship between radiological findings and patient's symptoms has been studied by several authors. These studies have reported that MRI imaging findings did not identify symptomatic from asymptomatic persons.^[2–5]

Unfortunately, many previous studies have some methodological limitations related to the assessment of patients' symptoms. Typically, the symptoms have been evaluated retrospectively from the patient records or otherwise rated without a standard methodology. The use of the standardized Oswestry Disability Index (ODI),^[6] Visual analog pain scale (VAS),^[7] Beck Depression Inventory (BDI),^[8] and specific back pain at rest and leg pain at walking items of the Numerical Rating Scale (LBP- and LP-NRS-11)^[9] have improved the accuracy and reproducibility of patients symptom and functional disability grading.

The purpose of this study was to investigate the role of anatomical changes on patient symptoms and functional disability. We compared the radiological findings to the symptoms and function of patients with LSS measured with standardized methods in a prospective study setting.

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Table 1. Clinical characteristics of the study subjects
	All patients (n = 80)	Moderate stenosis (n = 36)	Severe stenosis (n = 44)	P-value
Male/female	35/45 (43/56)	18/18 (50/50)	17/27 (39/61)	0.308
Marital status married or co-habiting	52 (65)	25 (69.5)	27 (61.3)	0.762
Current smoker	17 (21.3)	10 (27.7)	7 (16.0)	0.345
Previous lumbar operation	11 (13)	6 (16.7)	5 (11.4)	0.248
Depressed³	17 (21)	6 (16.7)	11 (25.0)	0.365
Minimal dural sac area^†	56.1 (21.9)	72.1 (18.0)	43.0 (15.2)	0.000
Age	63.0 (11.0)	62.0 (11.6)	64.0 (10.8)	0.413
BMI (kg/m²)	29.6 (4.0)	29.5 (4.4)	29.8 (3.5)	0.746
Number of somatic diseases	5.3 (3.0)	5.6 (3.2)	5.1 (2.8)	0.445
ODI	44.7 (16.1)	45.4 (18.0)	44.1 (14.4)	0.731
VAS overall	33.3 (23.9)	34.6 (24.7)	31.9 (25.0)	0.523
NRS LBP	4.1 (2.6)	4.72 (2.6)	3.59 (2.4)	0.059
NRS LP	6.49 (2.6)	7.33 (2.29)	5.80 (2.72)	0.008
BDI score	10.4 (6.1)	9.78 (6.86)	10.93 (5.546)	0.233
Walking distance (m)	545 (445)	421 (431)	646 (436)	0.021
Foraminal stenosis (normal/moderate/severe)^§		53/39/8	55/36/9	0.971
Multilevel stenosis yes/no^§		53/47	70/30	0.104
Lumbar fusion yes^§		33	66	0.258

Note: Except where indicated, data are numbers of patients, with percentages in parentheses or means, ± standard deviations in parentheses.
³BDI 15 or more points, ^†at the most stenotic level, mean (mm²), ± standard deviations in parentheses. ODI = Oswestry Disability Index (0–100), VAS overall = Visual analog pain scale (0–100), NRS LBP = Numerical rating scale low back pain at rest, scale (0–10), NRS LP = Numerical rating scale leg pain at walking, scale (0–10), BDI = Beck Depression Inventory (0–63), ^§Percentages.

Table 2. Correlation of the dural sac area with patient symptoms and walking capacity
	ODI scale	VAS overall scale	NRS LBP	NRS LP	Beck depression index	Treadmill test
Central spinal canal (mm2)	r = 0.086	r = −0.036	r = −0.004	r = 0.023	r = −0.099	r = −0.145
	P = 0.448	P = 0.752	P = 0.972	P = 0.841	P = 0.380	P = 0.200

r = Spearman correlation coefficients.
P = P values.
ODI = Oswestry Disability Index (0–100).
VAS overall = Visual analog pain scale (0–100).
NRS LBP = Numerical rating scale low back pain at rest (0–10).
NRS LP = Numerical rating scale leg pain at walking (0–10).
Treadmill exercise test (0–1000 m).
BDI = Beck Depression Inventory (0–63).