Early-onset facioscapulohumeral muscular dystrophy - significance of pelvic extensors in sagittal spinal imbalance.
Although facioscapulohumeral muscular dystrophy (FSHD) is the third most common inherited myopathy, cases of infantile or early-childhood onset have rarely been reported. The purpose of this study was to describe a case of early-onset FSHD with lumbar hyperlordosis, which shows the significance of the dynamic component of sagittal spinal imbalance. An 11-year-old girl presented with progressive gait disturbance and lumbar hyperlordosis. The motor power of her pelvic extensor muscles was grade 3. Pelvic tilt and hip flexion were markedly increased as determined by gait analysis. The most important factor in the development of hyperlordosis is the weakness of the pelvic extensor muscles, and the results of gait analysis exquisitely explain the pathophysiology. The patient stands with her spine hyperextended to maintain upright posture by a compensatory mechanism of relatively strong back extensor muscles. Corrective surgery for lumbar hyperlordosis was not considered because it could have eliminated the compensatory lumbar hyperextension, thus making the spine of the patient stoop forward through her hip joint during walking by the weakness of her pelvic extensor muscles. This FSHD case is an impressive example of a patient showing the concept that weak pelvic extensor muscles cannot keep the spine upright and balanced.
Lee
Choon Sung
CS
Department of Orthopaedic Surgery, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea.
Kang
Suk Jung
SJ
Hwang
Chang Ju
CJ
Lee
Sung-Woo
SW
Ahn
Young-Joon
YJ
Kim
Yung-Tae
YT
Lee
Dong-Ho
DH
Lee
Mi Young
MY
D002648:Child; D005260:Female; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D008141:Lordosis / Q000209:etiology / Q000503:physiopathology; D008159:Lumbar Vertebrae; D018908:Muscle Weakness / Q000209:etiology / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009133:Muscular Atrophy / Q000209:etiology / Q000503:physiopathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000150:complications / Q000503:physiopathology*; D016059:Range of Motion, Articular