Sudden proximal spinal dislocation with complete spinal cord injury 1 week after spinal fusion in a child with Prader-Willi syndrome: a case report.

STUDY DESIGN: Case report. OBJECTIVE: To describe a sudden spinal cord injury in a girl with Prader-Willi syndrome (PWS) 1 week after posterior T2-L3 fusion. SUMMARY OF BACKGROUND DATA: PWS is a genetic disorder characterized by several features including growth deficiency, hypotonia, obesity, and spinal deformities. In PWS patients the prevalence of scoliosis and of kyphosis is reported to be 15% to 86% and 8% to 40%, respectively. Operative treatment carries specific and serious risks in these patients. METHODS: A 13-year-old girl with PWS underwent a ventral release and a posterior spinal fusion for a scoliosis with hyperkyphosis of the thoracic spine. Preoperatively, she had no osteopenia or obesity. Posterior instrumentation consisted of fixation with pedicle screws, proximally assisted by a bilateral transverse hook to prevent junctional hyperkyphosis. RESULTS: Postoperative recovery was initially uneventful; however, 1 week after operation the patient suddenly suffered a complete spinal cord lesion at level T4. This was due to myelum compression with a spinal dislocation cranial to the fusion level, and subsequent proximal hook failure. The patient underwent immediate removal of the transverse hooks, an extension of the fusion to T1, and a laminectomy at T2. Eighteen months after the event she was still paraplegic. CONCLUSION: This report describes a sudden and complete spinal cord lesion 1 week after spinal fusion in a child with PWS. Although such an event is often attributed to osteopenia, this was not proven in this case. To our knowledge, this is the first report to describe this event developing so soon and so suddenly after primary surgery. This case report confirms that spinal surgery in patients with PWS carries an increased risk of junctional hyperkyphosis and pullout of hardware.

Bone scintigraphy after osteochondral autograft transplantation in the knee: 13 patients followed for 4 years.

BACKGROUND AND PURPOSE: Autologous osteochondral transplantation (OCT) is an established method of treating articular cartilage defects in the knee. However, the potential for donor site morbidity remains a concern. Both the restoration of the original cartilage defect and the evolution of the donor site defects can be evaluated by bone scintigraphy. Thus, we performed a prospective bone scintigraphic evaluation in patients who were treated with OCT. PATIENTS AND METHODS: In 13 patients with a symptomatic articular cartilage defect, bone scintigraphies were obtained preoperatively, 1 year after osteochondral transplantation, and finally at an average follow-up of 4 (2.5-5.5) years. The evolution of scintigraphic activity was evaluated for both the recipient and the donor site. Parallel, clinical scoring was performed using the Lysholm knee scoring scale, the Cincinnati knee rating system, and the Tegner activity score. RESULTS: The bone scintigraphic uptake was elevated at the involved femoral condyle preoperatively, and gradually decreased to normal levels in 7 of 11 cases. The originally normal uptake at the trochlea increased 1 year after transplantation. Then, a gradual decrease in uptake occurred again at this donor site to remain elevated at the final scintigraphy. A correlation was found between elevated scintigraphic activity and the presence of retropatellar crepitus. The mean Lysholm and Cincinnati scores had increased 1 year after transplantation. The mean Tegner score had increased 3 years after transplantation. INTERPRETATION: Elevated bone scintigraphic activity from an osteochondral lesion in the knee can be restored with OCT. However, increased scintigraphic activity is introduced at the donor site, which becomes reduced with longer follow-up. The use of fairly large osteochondral plugs appears to correlate with retropatellar crepitus and increased scintigraphic activity, and is not therefore recommended.