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A bone disorder characterized by marked hyperostosis
of the craniofacial bones and diaphyseal expansion of the tubular bones
resulting in significant clinical complications.
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Schäfer Stein Oshman Syndrome
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Fewer than 20 cases have been
described in the literature. Both autosomal recessive and dominant forms but
also sporadic cases have been described. In some cases the parents were
consanguineous.
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This syndrome is a metabolic bone disease
resulting in progressive and massive thickening and sclerosis of the skull,
mandible, maxilla, clavicles, and ribs. No surgical or medical cure is
available. Metabolic therapy with Calcitrol to promote osteoclastic
remodeling and restricted calcium intake to prevent hypercalcemia aimed at
controlling the process usually are not successful. The diagnosis is
confirmed by radiographs, which demonstrate diaphyseal expansion of tubular
bones with sclerosis and minimal metaphyseal expansion of the epiphyses, and
marked hyperostosis and sclerosis of the ribs, sternum, clavicles, and
scapulae. The humeri may show endosteal cortical thickening. Diaphyseal
undertubulation may lead to straightened humeri with cylindrical shape,
resembling a “policeman's nightstick” or a “truncheon.” Symptoms are
usually seen by approximately 3 months of age, but may start at birth and
progress with bone pain, pronounced deformities such as progressive cranial
hyperostosis with obliteration of the diploic spaces and the paranasal
sinuses, development of foraminal encroachment leading to neuropathy with
progressive deterioration of vision (nonreactive pupils have been described)
and hearing, obstruction of jugular venous outflow, chronic epiphora
secondary to nasolacrimal duct obstruction, chronic nasal obstruction
secondary to choanal stenosis (may lead to respiratory distress in infancy),
facial hyperostosis with overgrown nasal bridge, gross mandibular
hyperplasia relative to the maxilla with limited mouth opening from severe
immobility of the temporomandibular joints, facial muscle atrophy and
weakness, mild hydrocephalus with herniation of the cerebellar tonsils
through a small foramen magnum, cervical syringomyelia, mental retardation,
and restricted cervical spine (especially atlantoaxial) mobility. Flexion of
the neck may also be limited by the bulky mandible pressing against the chest,
whereas extension of the head may be limited by the bulky occiput. Death usually occurs in
childhood.
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The combination of choanal stenosis,
major mandibular hyperplasia, and significant limitation of mouth opening
and cervical spine mobility puts these children at very high risk for
difficult airway management. A clear backup plan must be in place prior to
induction of anesthesia. An awake fiberoptic intubation is the technique of choice. An induction technique
with maintenance of spontaneous ventilation may also be suitable. However, hypercapnia
should be avoided because intracranial pressure may be increased. Successful
tracheal intubation using a fiberoptic guided intubation through a laryngeal
mask has been reported in the literature. Prolonged postoperative mechanical
ventilation may be required, particularly when the surgery involves the
face. Tracheal extubation may be performed a few days later ...