Posterior correction without rib head resection for dystrophic kyphoscoliosis complicated with rib head protrusion into the central canal in type 1 neurofibromatosis

English Keywords:Dystrophic kyphoscoliosis  Neurofibromatosis type 1  Rib  Central canal

English Abstract:

  【Abstract】 Objectives: To discuss the safety and early outcome of posterior correction while remaining the rib head for dystrophic kyphoscoliosis complicated with rib head protrusion into the central canal in type 1 neurofibromatosis. Methods: 8 NF-1 patients with rib head displacement into spine canal underwent posterior correction from Febuary 2003 to April 2013. Data such as the Cobb angle of the scoliosis and kyphosis, trunk balance during pre- post- operation and follow-up were collected, the perioperative complications were also collected. Results: 8 cases (6 males and 2 females) with an average of 12.9 years(7-24 years) were included in our review. All except one experienced posterior fusion surgery, while the remaining underwent the growing rod correction. Both methods had rib head intact. The average follow-up time was 22.9 months and the average number of the instrumented segment was 10.1. The average surgery time was 3.3 hours and the average blood loss was 460ml. The pre- and post- operative thoracic cobb angle was 67.00° and 34.38° respectively and the average correction rate was 48.7%. On the other side, the sagittal plane Cobb angle was 62.50° and 31.25° respectively, the average correction rate was 49.9%. At the final follow-up at and average of 22.9 months, Cobb angle from the coronary plane and the sagittal plane was 35.75° and 33.38° respectively. Pre- post- operation and the follow up coronary trunk balance was 35.88mm, 15.63mm and 14.00mm respectively, and 35.13mm, 18.13mm and 15.50mm respectively in the sagittal plane. The rotation degree of the vertebrae before and after the surgery was 2.25°and 1.88° respectively, the apical vertebral offset was 49.38mm and 35.81mm. All rib head displacements were located in one level and around the scoliotic apex, pre-operative rib head displacement into spine canal accounted for 32.86%. Seven patients decreased from 33.36% before the surgery to 26.57% after the surgery despite of no significant change in the location of the rib head in two cases, the other five cases experienced incomplete recovery. Two cases had chest pain relieved after surgery. One case had pathological sign, which disappeared after surgery. Conclusions: Direct correction in the thoracic spine is safe and effective for NF1 patients with rib head displacement into spine canal and with no neurological deficit.