Dynamic computed tomography myelography including the prone position as a reliable preoperative imaging method for osteoporotic vertebral fracture with neurological deficits: A preliminary report of three cases
Toru Funayama1, Toshinori Tsukanishi2, Kentaro Mataki3, Tetsuya Abe1, Hiroshi Noguchi1, Hiroshi Kumagai2, Katsuya Nagashima2, Kousei Miura2, Masao Koda4, Masashi Yamazaki5
1 Assistant Professor, Department of Orthopedic Surgery, University of Tsukuba Tsukuba, Ibaraki, Japan
2 Spine Surgeon, Department of Orthopedic Surgery, Kenpoku Medical Center Takahagi Kyodo Hospital, Takahagi, Ibaraki, Japan
3 Spine Surgeon, Department of Orthopedic Surgery, Ichihara Hospital, Tsukuba Ibaraki, Japan
4 Associate Professor, Department of Orthopedic Surgery, University of Tsukuba Tsukuba, Ibaraki, Japan
5 Professor, Department of Orthopedic Surgery, University of Tsukuba Tsukuba, Ibaraki, Japan
Assistant Professor Department of Orthopedic Surgery, University of Tsukuba Tsukuba, Ibaraki
Source of Support: None, Conflict of Interest: None
Aims: Delayed paralysis after osteoporotic vertebral fracture (OVF) in the elderly is caused by severe compression on the spinal cord or the cauda equina from the collapsed vertebral fragment that is retropulsed into the spinal canal. Patients with retropulsion of the vertebral fragment that occupies approximately 40% or more of the spinal canal likely develop delayed paralysis, suggesting that narrowing of 40% is the critical point. However, whether or not a neural decompression procedure during posterior instrumentation surgery, such as laminectomy should be performed during the surgery is still controversial. We performed dynamic computed tomography myelography (CTM) including the prone (surgical) position with OVF to investigate if the severity of spinal cord and cauda equina compression during the surgery could be estimated in advance.
Materials and methods: The CTM was examined in 3 OVF patients (1 man and 2 women; mean age, 84 years) with neurological deficit in the supine and prone (surgical) positions to accurately estimate the necessity of decompression during surgery.
Results: The spinal narrowing was 50% or higher in the supine position, but was less than 40% in the prone position in two patients (fracture at the T11 and L1 vertebrae), indicating that decompression was not necessary. Decompression was required in one patient (fracture at the L2 vertebra) with a high narrowing rate of 57% in the supine position and 56% in the prone position.
Conclusion: Diagnostic imaging in the supine position alone will not help estimate the severity of intraoperative spinal cord or cauda equina compression because the degree of vertebral instability varies in each patient with OVF.