Premature pubarche and the growth of the trunk in paralysed children

Tethered spinal cord among individuals with myelomeningocele: an analysis of the National Spina Bifida Patient Registry

OBJECTIVE

The aims of this study were to review the National Spina Bifida Patient Registry (NSBPR) data set to study the rates of tethered spinal cord release (TCR) among patients with myelomeningocele and variability between centers, to compare TCR rates between males and females, and to study the relationships between TCR rates and other condition-specific characteristics.

METHODS

The NSBPR registry was queried to identify all patients with myelomeningocele. TCR rates were calculated over time using survival analyses; rates between centers and between males and females were compared. Cox proportional hazards models were constructed to identify relationships between TCR rates and sex, functional lesion level, ambulation status, treated hydrocephalus, and prior Chiari decompression.

RESULTS

Of 6339 patients with information about their operations, 1366 (21.5%) underwent TCR, with significant variability between centers. The majority (75.8%) underwent a single TCR. The annual TCR rate was linear between birth and 13 years (1.8%/year) but declined sharply from 14 to 21 years (0.7%/year). There was no period of time at which the TCR rate accelerated. There were no significant differences in TCR rates between males and females. TCR rate was not related to functional lesion level but was lower among nonambulators compared with community ambulators (p = 0.005) and among those with treated hydrocephalus (HR 0.30, p < 0.001), and higher among those having prior Chiari decompression (HR 1.71, p < 0.001).

CONCLUSIONS

These results extend the results of prior single-institution studies, demonstrate significant treatment variability between institutions, and challenge the traditional concept that tethering is related to spinal cord stretching due to spinal growth.

Spinal muscular atrophies

Spinal muscular atrophies (SMA) are genetic disorders characterized by degeneration of lower motor neurons. The most frequent form is caused by mutations of the survival motor neuron 1 gene (SMN1). The identification of this gene greatly improved diagnostic testing and family-planning options of SMA families. SMN plays a key role in metabolism of RNA. However, the link between RNA metabolism and motor neuron degeneration remains unknown. A defect in mRNA processing likely generates either a loss of function of some critical RNA or abnormal transcripts with toxic property for motor neurons. Mutations of SMN in various organisms highlighted an essential role of SMN in motor axon and neuromuscular junction development or maintenance. The quality of life of patients has greatly improved over recent decades through the improvement of care and management of patients. In addition, major advances in translational research have been made in the field of SMA. Various therapeutic strategies have been successfully developed aiming at acting on SMN2, a partially functional copy of the SMN1 gene which remains present in patients. Drugs have been identified and some are already at preclinical stages. Identifying molecules involved in the SMA degenerative process should represent additional attractive targets for therapeutics in SMA.

Evaluation of femur length during the second and third trimesters in fetuses with myelomeningocele

OBJECTIVES

To determine if the femur length of fetuses with myelomeningocele is shorter in the second and third trimesters compared with that of normal fetuses.

METHODS

We retrospectively collected measurements of femur length, head circumference, biparietal diameter and abdominal circumference from detailed obstetric ultrasound studies performed during the second and third trimesters in 31 fetuses with myelomeningocele and 43 fetuses with no detectable anomaly. The gestational age predicted by each parameter (based on Hadlock's tables) was compared with the true gestational age (based on last menstrual period), using the ANCOVA test to determine if there was a statistically significant difference between the two groups of fetuses.

RESULTS

There was no significant difference in femur length (P = 0.60) or in abdominal circumference (P = 0.85) between fetuses with myelomeningocele and normal fetuses. Fetuses with myelomeningocele did have a significantly lower biparietal diameter and head circumference (P < or = 0.001).

CONCLUSIONS

Myelomeningocele is not associated with reduced femur length in the second and third trimesters, suggesting that the known postnatal lower extremity foreshortening in patients with myelomeningocele develops late in gestation or after birth.

Adult stature and anthropomorphic measurements of patients with myelomeningocele

Children with myelomeningocele are extremely short, yet little data exists on adult stature and anthropomorphic measurements. We measured the recumbent length, weight, arm length, sitting height and calculated body mass index of 54 adults with myelomeningocele. Mid parental height was also calculated. Measurements were compared with normative data. Patient charts were reviewed for history of hydrocephalus. The 27 males and 27 females had a mean age of 24.8 +/- 5.7 years. The mean length for adult females was 141.9 +/- 12 cm and was 152.1 +/- 13 cm for males. Patients with thoracic level of lesions were shorter than those with lumbar level who were, in turn, shorter than those with sacral levels. Recumbent length, sitting height, arm length and arm span were significantly smaller than expected values. Recumbent length was smaller than mid parental height. Those with ventriculoperitoneal shunts, required for hydrocephalus, were shorter than these without a shunt.

CONCLUSION

Adults with myelomeningocele have significant short stature. Arm span is not an interchangeable measure with length for patients with myelomeningocele. Multiple factors are likely to be responsible for the observed short stature.

Anthropometry and obesity in myelomeningocele

Anthropometric data on 110 myelomeningocele (MMC) subjects in relation to age, sex, level of lesion and ambulation were studied to investigate growth and the occurrence of obesity in MMC. In 52 subjects, indices of obesity were validated against body composition analysis of total body fat (%BF) using body potassium and body water techniques. Most subjects were short and light compared to reference data and became relatively shorter and heavier with age. Overall trunk growth was not affected by the level of lesion, but sitting height was affected by kyphoscoliosis. Arm spans were similar to reference data, but were significantly greater in wheelchair users. Leg length was greatest in those who walked. Body composition data showed excess adipose in many MMC subjects, this tendency increasing with age. When correlated with %BF determined from body composition analysis, common clinical indices of obesity had variable r values (wt/ht2 0.78; wt/sitting ht2 0.77; upper arm fat area 0.75; triceps skinfold 0.74; wt/arm span2 0.68, with the 4 skinfold method correlating best, 0.82). Anthropometric measures, taken with cognizance of level of disability and mobility, can accurately assess body growth and the occurrence of obesity in MMC. The influence of ambulatory activity in promoting normal growth is emphasized.

Growth of trunk and legs of children with myelomeningocele

Total body length and body segments (crown-rump length, sub-ischeal length) of 78 children with myelomeningocele were measured at regular intervals during growth for a mean duration of 4.4 years. These children were shown to have defective growth, with an increased upper segment/lower segment ratio. It was found that the higher the level of the meningocele the greater the growth defects. However, the relationship was statistically significant only for the first seven years of life. It is concluded that neurological damage was mainly responsible for defective growth during the first years of life, but that other factors independent of the level of the meningocele also come into play in later years.

Trunk and leg growth in children with paraplegia caused by spinal cord injury

After a survey of the bibliography on the subject of clinical and experimental data on retarded growth in children affected by lesions of the peripheral nervous system, the authors present a semi-longitudinal analysis of the anthropometric values obtained by spinal cord section in the case of young paraplegics. By this means, they demonstrate an average growth defect of the order of two standard deviations which only affects the body distal to the neurological lesion in cervical or dorsal injuries. The lower the level of the cord lesion and the earlier the paralysis the greater the growth defects.