Spondylocostal dysostosis with lipomyelomeningocele: Case report and review of the literature.

Spondylocostal dysostosis (SCDO) is rare anomaly caused due to flawed embryological development of the axial skeleton during preliminary stages of gravidity, characterized by malformed vertebral column and ribs, abridged thorax and kyphoscoliosis. This entity was also reported as a "Jarcho-Levin syndrome" eponym by erstwhile authors, before the introduction of genetic based classification. A literature review showed only three cases of this clinical entity with lipomyelomeningocele. We report the fourth case report of an infant with SCDO with lipomyelomeningocele. His chest X-ray displayed absent left side 6(th)-8(th) ribs with peculiar fan like configuration, making the heart vulnerable to any direct injury. Special care has to be taken for such patients who need surgical procedure in the prone position.

Introduction

Spondylocostal dysostosis (SCDO) is a rare, heritable axial skeleton growth disorder characterized by malformed vertebral column and ribs, abridged thorax, and kyphoscoliosis. Very few such cases have been reported so far in the literature. We present here an infant with SCDO with neural tube defect who underwent lipomyelomeningocele excision and detethering of the cord.

Case Report

An 8-month-old male child was admitted with a history of soft, nonprogressive swelling in the lower back since birth. This child was a product of nonconsanguinous marriage, born full term by cesarean section. The fetus was diagnosed to have neural tube defect on antenatal scan, but the pregnancy was deemed precious and hence continued. He was the second child born after 10 years of marriage. The mother had a history of two previous abortions due to malformed fetus. The first female child was 3 years old and did not have any congenital abnormality. Both the father and mother did not have any other comorbid conditions.

On examination, the child was conscious, alert, and active. Neurological examination revealed right foot wasting and weakness with equinovarus deformity. Examination of the thorax revealed a shortened thorax with deficient rib cage on the left side. Second, a soft, mid-line swelling was present in the lumbosacral region, which was non-compressible and nontransilluminant with no overlying skin defect or leak. Physical examination did not reveal any associated stigmata such as short neck, abnormal facial feature, thoracic asymmetry, polythelia, inguinal swelling, undescended testis or anal atresia. Chest X-ray displayed absent left sixth to eighth ribs and fan like configuration of ribs, seventh and ninth butterfly shaped thoracic vertebrae and mild scoliosis of the thoracolumbar spine [Figure 1]. Magnetic resonance imaging revealed lumbosacral lipomyelomeningocele with low lying cord at L4–L5 level with tethered cord [Figure 2]. He underwent excision and repair of lipomyelomeningocele and detethering of cord under general anesthesia in the prone position with appropriate padding to avoid direct pressure on the heart. Both the intraoperative and postoperative period was uneventful without any further deterioration in neurological function.

Figure 1

Chest X-ray: Absent left 6th to 8th ribs with its fan like configuration, 7th and 9th butterfly shaped thoracic vertebrae and mild scoliosis of thoracolumbar spine

Figure 2

Magnetic resonance imaging spine: (a) T1-weighted Sagittal image and (b) T2-weighted Sagittal image displaying lumbosacral lipomyelomeningocele with low lying cord at L4–L5 level with tethered cord and deformed 7th and 9th thoracic vertebrae (c) T2-weighted axial image at L4–L5 spinal level showing lipomyelomeningocele communicating through vertebral defect (d) short inversion time inversion recovery coronal image demonstrating deficient and malformed rib cage on left side

Discussion

Spondylocostal dysostosis is a rare anomaly caused due to defective embryological development of the axial skeleton during early stages of gestation. In 1938, Saul Jarcho and Paul Levin at John Hopkins University had first described a pattern of vertebral and costal anomalies distinctly different from the well-known Klippel–Feil syndrome.[1] Since then Jarcho–Levin syndrome (JLS) eponym has been used for varied malady like – hereditary multiple hemivertebrae, spondylocostal dysplasia, spondylothoracic dysplasia, costovertebral anomalies and costovertebral dysplasia. This “JLS” eponym was used by many authors for “SCDO” before the introduction of genetic based classification.[23456]

Five subtypes of SCDO are recognized, based on the underlying gene involved. JLS is recently classified as SCDO1 (SCDO type 1).[7] SCDO1 and SCDO4 have been found to be associated with neural tube defects like spina bifida, meningocele, meningomyelocoele, lipomyelomeningocele, and diastematomyelia. SCDO1 is caused by an abnormality in the DLL3 gene located on chromosome 19 at 19q13. SCDO4 is caused by an abnormality in the HES7 gene located on chromosome 17 at 17p13.[7]

According to Dias and Walker, split cord malformations and related malformations occur as a result of embryological failure of the mid-line axial integration during gastrulation.[8] The common association of segmental costovertebral malformations with neural tube defects could be related to an early gastrulation genomic defect or one after gastrulation when there are two independent somatic columns. The latter sometimes progresses and then involves primary and secondary neurulation. Lipomyelomeningocele results due to premature disjunction during primary neurulation.[9] Due to ingression of adjacent mesenchymal cells (sclerotome) into the central canal of developing neural tube, the somatic tissues are laterally displaced. This would form an abnormally widened spinal canal with numerous associated vertebral segmentation anomalies, including sagittal cleft (butterfly) vertebrae or hemi vertebrae. And thus due to deficient sclerotome for embryogenesis, the ribs are malformed or absent as also seen in the present case.

The patients with SCDO are prone to respiratory insufficiency and repeated respiratory infections (pneumonia) because the vertebrae are fused and the ribs fail to develop properly and the chest cavity is too small to accommodate the growing lungs. Other abnormalities associated with this syndrome includes Chiari malformation, renal/urinary tract abnormalities, hydrocephalus, hydroureteronephrosis.[10]

Till date, about 17 cases of SCDO with neural tube defects have been described in the literature as reckoned in the table[23456911121314151617] [Table 1]. Amid these only three cases of SCDO reported had lipomyelomeningocele, which encompasses one by Duru et al.[9] and two cases by Nadkarni et al.[11] Present case is the fourth case report of lipomyelomeningocele with SCDO. He presented with rib defect on the left side making the heart vulnerable to any direct injury. In such patients, care has to be taken during surgery in the prone position to avoid direct pressure on the heart and also parents need to be counseled about the same. Our patient had a smooth postoperative recovery. Sometimes these patients because of the shortened thorax and its asymmetry, weaning may be difficult, and this may result in respiratory complications and increase in ventilator days. These patients should be thoroughly investigated for other associated anomalies before taking up for surgery. As these patients may be associated with renal abnormalities, perioperative hemodynamics and urine output monitoring are mandatory to prevent any insult to the kidneys.

Table 1

Case reports of SCDO with neural tube defects

Conclusion

It is important to thoroughly investigate the neural tube defect patient and to rule out the associated abnormalities. Management of such patients should aim at aggressive neonatal care and prevention of respiratory infections. Also, precautions must be taken to prevent direct trauma to heart or lungs in view of deficient rib cage. Additional genetic and embryological studies are necessary to provide evidence of an etiological link between SCDO and neural tube defect.