Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Spine
Abstract number: 24164
BLOOD VOLUME CHANGE IN LOWER BACK MUSCLES IN HEALTHY MALES
AND PATIENTS WITH LUMBAR SPINAL STENOSIS.
Sueo NAKAMA, Masaki KATO, Minoru ENDO, Ryo HARADA, Tomohide KOHNO
Department of Orthopaedics, Shimotsuga General Hospital, Tochigi-shi, Tochigi
(JAPAN)
Near-infrared spectroscopy (NIRS) has made it possible to measure in vivo changes
in hemoglobin oxygenation and blood volume in contracting muscles. The purpose of
this study is to investigate the hemodynamics of the back extensor muscles during
various tasks. Using NIRS, we measured regional oxygen saturation (rSO2) and
hemoglobin index (HbI), which indicates the change in the total hemoglobin volume,
in 12 healthy males (mean age: 23.8 years) and 6 patients (mean age: 68.8 years)
with symptomatic lumbar spinal stenosis. In healthy males, HbI did not show a
definite trend on horizontal back extension (concentric contraction), but increased
markedly during sitting, forward flexion, and flexion with weight-bearing (eccentric
contraction), and immediately returned to the initial level on adopting an erect
posture. The rSO2 decreased conversely according to the magnitude of the task. HbI
and rSO2 showed the same pattern in all healthy subjects. It is suggested that
eccentric contraction of the lower back muscles involves different hemodynamics and
metabolism compared to concentric contraction. In tasks involving sitting and forward
flexion of the upper body, the back muscles are in a congestive state in terms of
blood flow. Conversely, in 3 patients with LSS, HbI increased during sitting and
forward flexion and it remained high level even in the upright position. In 2 patients
with LSS, HbI decreased markedly during forward flexion in upright position. We
found that hemodynamics in lower back muscles in patients with LSS is quite
different compared to healthy subjects.
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