Surgical Management of Intracanal Rib Head Dislocation in Neurofibromatosis Type 1 Dystrophic Kyphoscoliosis: Report of Two Cases and Literature Review

Management of NF-1 dystrophic scoliosis associated with rib heads dislocation into the spinal canal in neurological intact patients: a systematic literature review

PURPOSE

The management of scoliosis and kyphoscoliosis in patients with Type 1 Neurofibromatosis (NF-1) among spinal surgeons is still challenging due to the severity of the deformity especially in dystrophic deformity types. This rapid and progressive condition is likely to be associated with dislocated rib heads into the spinal canal, hence representing a real dilemma on the decision making between its resection versus not resection during the corrective surgery, especially in patients with normal neurological status. The objective of this publication is to discuss the management options in this patient population through a literature review.

METHODS

A comprehensive systematic literature search was performed for relevant studies using PubMed, Web of Science, and Scopus databases. Previous publications depicting neurologically intact patients with NF-1 and rib dislocation into the canal were reviewed. Articles reporting individual cases or case series/cohorts with patient-discriminated findings were included.

RESULTS

The data collection retrieved a total of 55 neurologically intact patients with NF-1 dystrophic scoliosis and rib penetration into the canal who underwent spinal surgery. Among them, 37 patients underwent surgery without head rib resection and 18 patients with rib excision. No patient presented postoperative neurological deficit except for one case of late postoperative neurological deterioration reported in a patient within situ fusion in which the surgeons ignored the presence of previous spinal cord compression.

CONCLUSION

Corrective surgery for patients with NF-1 and rib penetration into the canal in neurologically intact patients can be safely performed without the resection of the dislocated rib heads without a higher risk of neurological compromise.

Surgical treatment of post-traumatic luxation of rib heads with spinal cord compression in a cat

BACKGROUND

Luxation of the rib head with intrusion into the intervertebral foramen seems to be rare in cats. Only one report has been published describing a cat with non-ambulatory paraparesis, which was managed conservatively. Here we report a case of rib head luxation that was managed surgically.

CASE PRESENTATION

A 4-year-old, female domestic shorthair cat with a two-week history of non-ambulatory paraparesis was presented at our clinic. Based on history and neurological examination, a diagnosis of thoracolumbar spinal cord lesion of traumatic origin was made. Computed tomography scanning revealed mild scoliosis, a luxation of the 3rd and 4th right rib heads and penetration into the spinal canal through intervertbral foramina. Surgical management using right dorsal approach to the spine was performed. The spinal cord was decompressed by cutting and removing of proximal ribs' fragments by rotation and pulling out from the intervertebral foramina. The cat was ambulatory and paraparetic four weeks after surgery. Two years after surgery the cat regained functional gait, but ataxia remained.

CONCLUSIONS

We report the first case of a surgical treatment of rib head luxation and intrusion into the spinal canal in a cat. The applied procedure resulted in an improvement of neurological signs.

Rib head dislocation causing spinal canal stenosis in a child with neurofibromatosis, type 1

A 10-year-old female with neurofibromatosis type 1 and severe dystrophic scoliosis presented with a two-month history of difficulty ambulating due to low back pain. The patient did not have any neurological symptoms. MRI of the thoracolumbar spine demonstrated subluxation of the right posterior tenth and eleventh ribs through their respective neural foramina, with mild mass effect on the thecal sac without abnormal cord signal or cord compression. Groups of neurofibromas were present along the right ribs and paravertebral soft tissues around these levels. CT evaluation was completed for greater osseous definition. Cases of rib head dislocation into the central canal in the setting of dystrophic scoliosis were documented in only a limited sample of case reports. The angulated short-segment curvature in dystrophic scoliosis causes vertebral body rotation, foraminal enlargement, spindling of transverse processes, and penciling of the apical ribs. These changes can alter the articulation of the rib along the transverse process. The enlarged foramina can also create a larger space into which a rib may displace. As a result, in most reported cases, the subluxed ribs were on the convex apex of the curve in the mid-to-lower thoracic region. The risk of cord injury from rib head dislocation makes the complete depiction of the anatomy essential for proper surgical management.