Kyphoscoliosis associated with congenital neuromuscular disease with uniform type 1 fibers

Abstract

Objective: To report the first case of surgical treatment for severe kyphoscoliosis associated with respiratory disorder in a patient with congenital neuromuscular disease with uniform type 1 fibers (CNMDU1), including management of the possible onset of malignant hyperthermia (MH) in general anesthesia. CNMDU1 is rare among congenital neuromuscular diseases, and surgery for spinal deformity in CNMDU1 has not been described. Onset of MH in general anesthesia is a concern in this disease.

Methods: A 13-year-old female with motor retardation, suspected myopathy, and severe spinal deformity was followed at another pediatric hospital before referral to Meijo Hospital. Symptoms at the initial consultation were mild general muscular weakness and muscular atrophy. The rib hump was 60° and trunk balance was poor. The tendon reflex showed hyporeflexia, and blood tests were normal. Vital capacity was 0.69 L and forced expiratory volume percentage in 1 s was 75.5%, showing a restrictive and obstructive ventilatory defect. A plain radiograph showed severe kyphoscoliosis with thoracic scoliosis of 130° (T5-L1) and thoracic kyphosis of 110° (T2-T12) with almost no flexibility in bending or traction film.

Results: After preoperative halo traction for 2 months, one-stage anterior and posterior correction and fusion from T2 to L3 was conducted. MH did not occur, but recovery of respiratory function required 8 days by intubation after surgery. Postoperatively, thoracic kyphosis improved to 25° and thoracic scoliosis was 66° (correction rate: 49%). Pathological results of an intraoperative muscle biopsy from the paraspinal muscles confirmed the diagnosis of CNMDU1. At 6 years after surgery, the patient has no problems in daily life and no respiratory difficulty.

Conclusion: Spinal deformity in CNMDU1 has a risk of severe progression, which makes early diagnosis by biopsy important. The surgery may be recommended before severe progression of spinal deformity and respiratory disorder. Perioperative MH is a concern, but can be managed by appropriate procedures.

Fig. 1

Preoperative plain radiographs, a plain radiograph showing severe scoliosis of 44° (T1–T5), 130° (T5–L1), and 43° (L1–L5); b lateral radiograph showing severe thoracic kyphosis of 110° (T2–T12) and 64° (T12–L5); c–e bending (c, d) and traction (e) radiographs showing rigid thoracic scoliosis that could be corrected only to a limited extent

Fig. 2

Preoperative CT findings. deformity, and narrowing of the thorax were apparent due to severe spinal deformity. Vital capacity was 0.69 L, indicating ventilatory impairment

Fig. 3

Postoperative plain radiographs. a Frontal radiograph; b lateral radiograph. Thoracic kyphosis was corrected to 25°, but the postoperative thoracic curve was 66° and the percentage correction was only 49%

Fig. 4

Pathological findings. Almost 100% of fibers were type 1 with slightly different sizes. There were no type 2 fibers. Nemaline rods, central core, ragged red fibers, peripheral halo, and rounding cells were not found. a NADH-TR; b ATPase, pH 4.5, ×200)