The spectrum of the so-called rigid spine syndrome: nosological considerations and report of three female cases

Mortality and morbidity associated with correction of severe cervical hyperextension

STUDY DESIGN

Three case reports of patients with treatment of severe cervical hyperextension.

OBJECTIVE

Cervical hyperextension is a rare spine deformity that is associated with myopathies. Previous reports of surgical correction have reported no major operative complications. This report outlines our experience with 3 patients who experienced significant complications.

SUMMARY OF BACKGROUND DATA

The limited literature on the treatment of cervical hyperextension has good to excellent outcomes.

METHODS

Three case reports are presented.

RESULTS

Three cases with severe cervical hyperextension with intraoperative correction had associated morbidity and mortality. One case had a failed intubation requiring tracheotomy. This was followed by a successful posterior release with halo traction for 2 weeks and then an instrumented posterior cervical fusion. This patient died at home 2 weeks after surgery. The second and third cases had an intraoperative spinal cord injury during a posterior release for cervical hyperextension.

CONCLUSION

Patients with severe cervical hyperextension have high neurologic perioperative risk.

Rigid spine syndrome: a radiologic and manometric study of the pharynx and esophagus

The rigid spine syndrome (RSS) is not a recognized cause of dysphagia. The "vacuolar variant" of RSS causes mild, generalized, and slowly progressive weakness. Respiratory evaluation detected severe restrictive chest wall defect and significant respiratory muscle weakness. We identified nine patients at our Neuromuscular Clinic over a period of years. The aim of this evaluation was to ascertain whether pharyngoesophageal dysfunction caused cough (2/9), intermittent oropharyngeal dysphagia (4/9), and aspiration pneumonia (3/9). Pharyngeal and esophageal functions were evaluated separately by conventional cineradiography and intraluminal esophageal manometry over a one-year study period. An age- and gender-matched volunteer group without swallowing complaints partook in the manometric component of the study. There were seven male and two female patients. The mean age of patients was 19.1 years (17.8 years for controls), and the age range was 11-36 years (13-32 years for controls). The mean disease duration was 17.2 years (range=8-31 years). Patients were commonly underweight (7/9). Cineradiology detected abnormal swallow physiology of pharyngeal striated muscle (1/9) and of esophageal smooth muscle (2/9). Mean manometric pressures in patients were not significantly different from control data. Manometry detected "nonspecific" contractility abnormalities (3/9) that were not reflected in the mean data. The relative lack of instrumental findings suggested minor upper alimentary tract dysmotility in patients with the RSS. The myopathy that underlies this syndrome likely caused dysfunction of the striated muscle of the pharyngeal constrictors and upper esophageal sphincter. The documented abnormalities of esophageal smooth muscle motility were nonspecific and tenuously associated with the muscle disorder. The incongruity between complaints of intermittent dysphagia and study results was perhaps due to transient pharyngoesophageal dysmotility, altered swallowing mechanics of limited cervical spine mobility, altered swallowing perception after previous intubation/tracheostomy, or a "functional" upper intestinal complaint.

SEPN1: Associated with congenital fiber-type disproportion and insulin resistance

OBJECTIVE

Our first objective was to determine whether SEPN1 gene mutations are a cause of congenital fiber-type disproportion (CFTD), a rare form of congenital myopathy in which relative hypotrophy of type 1 (slow twitch) muscle fibers is the principal abnormality on histology. Second, we investigated an association between SEPN1-related myopathy and insulin resistance.

METHODS

We sequenced SEPN1 in five unrelated CFTD patients with scoliosis and respiratory muscle weakness and screened an additional 22 CFTD patients for abnormalities in SEPN1 by Western blotting and restriction digest for the 943G-->A mutation. We performed oral glucose tolerance tests (OGTTs) in eight SEPN1-related myopathy patients.

RESULTS

Two sisters with CFTD were homozygous for the 943G-->A SEPN1 mutation and had clinical features typical of previously reported patients with SEPN1-related myopathy. Five of eight SEPN1-related myopathy patients had abnormalities on OGTT suggestive of insulin resistance.

INTERPRETATION

SEPN1 is the second genetic cause of CFTD and the first cause of autosomal recessive CFTD to be identified to our knowledge. CFTD is the fourth clinicopathological presentation that can be associated with mutations in SEPN1. Insulin resistance may be a specific, previously unrecognized aspect of SEPN1-related myopathy.

Congenital Fiber Type Disproportion—30 Years On

Thirty years ago, M. H. Brooke coined the term "congenital fiber type disproportion" (CFTD) to describe 12 children who had clinical features of a congenital myopathy and relative type 1 fiber hypotrophy on muscle biopsy. It is now clear that this histological pattern can accompany a wide range of neurological disorders, leading to disillusionment with CFTD as a distinct nosological entity. To determine whether the CFTD has clinical utility as a diagnostic entity, we have reviewed the literature for cases of type 1 fiber hypotrophy and have used strict exclusion criteria to identify 67 cases of CFTD. Most patients presented at birth with weakness and hypotonia, had normal intelligence, and followed a static or improving clinical course. In 43% of families, more than 1 individual was affected. Failure to thrive was common and 25% of patients had contractures or spinal deformities. Bulbar weakness and ophthalmoplegia were less common and cardiac involvement was rare. Twenty-five percent followed a severe course and 10% had died at the time of reporting, all from respiratory failure. Ophthalmoplegia and facial and bulbar weakness were significantly associated with a poorer prognosis. The relatively homogeneous phenotype supports the retention of CFTD as a distinct diagnostic entity and familial occurrence suggests a genetic basis. Regarding the diagnosis of CFTD, we found no strong evidence that the minimum difference between type 1 and type 2 fiber sizes should be increased from 12% to 25%. We also list the other reported causes of relative type 1 fiber hypotrophy to aid their exclusion from CFTD.

Congenital fibre type disproportion a time-locked diagnosis: a clinical and morphological follow-up study

This is the first report that describes the clinical and histological findings in a patient suffering from pure congenital fibre type disproportion (CFTD), who had two biopsies with an interval of 16 years. Additionally, we compared the clinical signs and symptoms of the present case to those of 35 CFTD cases reviewed from the literature. From this we conclude that smallness of type I fibre diameter is not a characteristic feature during the course of pure CFTD. This suggests that CFTD is a time-locked diagnosis.

Genetic heterogeneity of congenital muscular dystrophy with rigid spine syndrome

Rigid spine syndrome is a neuromuscular disorder characterised by early rigidity of the spine due to axial muscle contractures, generally associated with muscle weakness, limb-joint contractures, and often respiratory failure. This phenotype may be associated with several muscular diseases. In cases of merosin-positive congenital muscular dystrophies (CMD) with rigid spine syndrome, we have recently identified a new locus (RSMD1) on chromosome 1p35-36. In the present study, we report the clinical, morphological and genetic analysis of other patients affected by a CMD with rigid spine syndrome from nine consanguineous families. Homozygosity mapping showed that the disease was linked to RSMD1 in one of the nine families. The other families were excluded from RSMD1, and the patients presented highly variable phenotypes suggesting the involvement of more than one gene defect in rigid spine syndrome. Nevertheless, a subgroup of patients who never walked, and had very early rigidity of the spine and scoliosis, may be considered for further genetic analysis.

Anaesthetic implications of rigid spine syndrome

The perioperative management of a 14-year-old girl, suffering from the muscular disorder rigid spine syndrome, is presented. The anaesthetic implications with regard to possible difficult intubation, cardiac involvement, malignant hyperthermia, neuromuscular blocking agents, and postoperative recovery are discussed.

Rigid spine syndrome. Case report

We describe a patient who had difficulty in walking since toddling stage and presented proximal upper and lower member weakness which have evolved to a progressive limitation of neck and trunk flexure, compatible with rigid spine syndrome. The serum muscle enzymes were somewhat elevated and the electromyography showed a myopatic change. The muscle biopsy demonstrated an active and chronic myopathy. The DNA analysis through PCR did not display any abnormality for dystrophin gene. The dystrophin by immunofluorescence was present in all fibers, but some interruptions were found in the plasma membrane giving it the appearance of a rosary. The test for merosin was normal.

Identification of a new locus for a peculiar form of congenital muscular dystrophy with early rigidity of the spine, on chromosome 1p35-36

Classical congenital muscular dystrophies (CMDs) are autosomal recessive neuromuscular disorders characterized by early onset of hypotonia and weakness, atrophy of limbs and trunk muscles, contractures, and dystrophic changes in the muscle biopsy. So far, only one gene, LAMA2 (6q2), which encodes the laminin alpha2 chain (or merosin), has been identified in these disorders. Mutations in LAMA2 cause CMD with complete or partial merosin deficiency, detectable by immunocytochemistry on muscle biopsies, and account for approximately 50% of CMD cases. In a large consanguineous family (11 siblings) comprising three children affected by CMD without merosin deficiency, we undertook a genomewide search by homozygosity mapping and analyzed 380 microsatellite markers. The affected children were homozygous for several markers on chromosome 1p35-36. We identified two additional consanguineous families with affected children who also showed linkage to this locus. A maximum cumulative LOD score of 4.48, at a recombination fraction of .00, was obtained with D1S2885. A consistent feature in these three families was the presence of early rigidity of the spine, scoliosis, and reduced vital capacity, as found in rigid-spine syndrome (RSS). This study is the first description of a locus for a merosin-positive CMD and will help to better define the nosology of RSS.

Two siblings with nemaline myopathy presenting with rigid spine syndrome

Two siblings, ages 20 and 19 presented with more than 10 yr history of spinal rigidity and scoliosis. The parents were first cousins. Muscle biopsies were consistent with nemaline myopathy. This has been the first association between a familial rigid spine syndrome and nemaline myopathy.

The rigid spine syndrome: a vacuolar variant

The rigid spine syndrome encompasses a number of disorders. We report 7 males and 2 females with this phenotype and a single, not previously reported, nosology. The salient muscle histological features were autophagic vacuoles, vacuoles containing capillaries, muscle spindle swelling, and type I fiber predominance. Disease onset was before age 6 years in all patients. Inheritance was probably autosomal recessive as siblings were affected in two families. Pulmonary function tests showed severely restricted ventilation, 3 patients required nocturnal ventilatory assistance, 2 patients had cor pulmonale, and mitral valve abnormalities were common. Serum CK levels were moderately elevated. EMG studies showed evidence of an active, chronic myopathy. The mean motor unit potential duration was statistically significantly shorter compared to controls in the triceps and anterior tibial muscles. Single fiber EMG "jitter" and evoked potential studies were normal.

Familial autosomal recessive rigid spine syndrome with neurogenic facio-scapulo-peroneal muscle atrophy

Two sisters and a first cousin presented with rigid spine and facio-scapulo-peroneal muscle atrophy. The patients belonged to a family with two first-cousin marriages. Electromyography, muscle and nerve biopsy showed neurogenic muscle atrophy without peripheral nerve involvement. Follow up did not show progression of the disease. This is the first observation of an association of neurogenic facio-scapulo-peroneal and rigid spine syndrome. The double first-cousin marriage suggests autosomal recessive inheritance.

Histopathological heterogeneity and cytopathological similarity of findings in different muscles of two brothers affected by rigid spine syndrome

The pathological changes in muscles biopsied from 2 brothers with rigid spine syndrome are reported. The findings ranged from marked fascicular atrophy and fibrosis to hypotrophy of small groups of fibres and vacuolation in most fibres. The presence of vacuoles and deposits of accumulated material seemed to be common to all the biopsies. These findings, compared with those reported in the literature, confirmed the histopathological heterogeneity of this syndrome but proposed also the hypothesis that similar elementary lesions of muscle fibres can account for the initiation of the pathological process, developing asynchronously in different muscles because of their different activity.

Late onset scleroatonic familial myopathy (Ullrich disease): a study of two sibs

We report on sibs with scleroatonic familial myopathy (Ullrich disease). Muscular weakness was of relatively late onset in relation to other cases reported in the literature. Short stature and moderate growth hormone deficiency were noted during follow-up. Differential diagnosis with other neuromuscular disorders, particularly rigid spine syndrome, is discussed.

The rigid spine syndrome in two sisters

Two half-sisters aged 14 and 18 years are described with a rigid spine syndrome as the cardinal clinical feature of an autosomal dominant neuromuscular disorder. Ten years previously, a diagnosis of multicore disease had been made from the clinical signs and muscle biopsy findings. Long term follow-up revealed a non-specific muscular dystrophy with axial predominance and a rigid spine in the younger girl; the older sister presented at the age of 18 with a rigid spine as the only myopathic sign. Computed tomography of the muscles showed severe involvement of the paraspinal musculature, in contrast with either less or no involvement of the other muscles.