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|Year : 2017 | Volume
| Issue : 1 | Page : 223-224
Type 1 neurofibromatosis with intracanalicular rib head dislocation
Venkata R C Vemula, Chandramouliswara P Bodapati, Krishna Mohan, Sudarshan Agarwal
Department of Neurosurgery, Sri Venkateswara Institute of Medical Sciences (SVIMS), Tirupati, Andhra Pradesh, India
|Date of Web Publication||12-Jan-2017|
Venkata R C Vemula
Department of Neurosurgery, Sri Venkateswara Institute of Medical Sciences (SVIMS), Tirupati - 517 507, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Vemula VR, Bodapati CP, Mohan K, Agarwal S. Type 1 neurofibromatosis with intracanalicular rib head dislocation. Neurol India 2017;65:223-4
Scoliosis is the most (occurring in 10–64% patients ) skeletal manifestation of neurofibromatosis type 1 (NF1). Two patterns of scoliosis are seen in these patients. Type 1 or nondystrophic scoliosis is similar to idiopathic scoliosis and is treated accordingly. Type 2 or dystrophic scoliosis is a short, segmental, angulated curve with severe kyphosis, and is often accompanied by rib penciling, vertebral wedging and enlargement of the neural foramina. A rare condition associated with the dystrophic scoliotic curves is dislocation of the rib heads on the convex side of the curve, with their displacement into the spinal canal through the enlarged neural foramina causing neurological impairment. Owing to the rarity of this condition, there is no consensus on the management of rib dislocations. Based on the available literature, rib head resection  is done in patients presenting with neurological impairment, and if the rib head is unresectable due to cord adhesions, a rib shaft osteotomy  is advocated. In asymptomatic patients with no evidence of spinal cord compression, rib head resection is questionable. A spontaneous rib head reduction is documented in patients following the curve correction with posterior fusion and segmental instrumentation. Dystrophic scoliosis should be suspected in any patient with NF1 and spinal anomaly, and a thorough imaging should be done to rule out rib dislocation.
A 14-year-old boy, a known case of NF1, presented with a 4-month history of deformity over the mid back and difficulty in walking, being bedridden for the past 2 months. On examination, the patient had café au lait spots [Figure 1]a, Lisch nodules, axillary freckling, and deformity [Figure 1]b in the thoracic region. Neurological examination revealed weakness of bilateral lower limbs (3/5 power), spasticity, and a sensory loss below D10 vertebral level. The imaging revealed a short segmental scoliotic curve with the apex at D8 vertebral level with convexity towards the right side [Figure 1]d and the presence of internal dislocation of the rib heads into the spinal canal at the vertebral levels D8,9, and 10 [Figure 1]c. The patient underwent deformity correction with segmental posterior instrumentation from D5 to D12 after resecting the dislocated rib heads under intraoperative neuromonitoring. There was significant correction of the curve [Figure 1]e, and the patient improved neurologically; the patient was ambulant at a 6-month follow-up.
|Figure 1: (a) Clinical photograph showing the cafe au lait spots; (b) clinical photograph showing the dorsal deformity; (c) axial computed tomography showing the internal dislocation of the rib head into the spinal canal; (d) X-ray of the dorsal spine showing a short segmental scoliotic curve with the apex at D8 and convexity to the right; (e) Postoperative X-ray of the dorsal spine showing a significant correction of the scoliosis|
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