The data were retrospectively collected at National Taiwan University Hospital and Min-Sheng General Hospital between May 2006 and November 2010. Each patient included was indicated for surgical intervention in the thoracic or lumbar spine region. The indications reported for the patients in this study were intractable back pain due to acute or chronic VCF, pain refractory to nonsurgical treatment for more than 6 months, or bony cleft formation in the vertebral body. The contraindications were primary or metastatic lesions with vertebral fractures, an infectious origin or poor general condition with a high risk requirement of general anesthesia. This study included 46 consecutive patients with single-level osteoporotic thoracolumbar fractures. Twenty-two patients who consulted PQC were allocated to Group I and received treatment of short-segment fixation with I-VEP. Twenty-four patients who consulted another senior orthopedic surgeon (CDW) were allocated to Group II and received treatment of KP. The study was in compliance with the WMA Declaration of Helsinki. The study based exclusively on clinical records was conducted retrospectively and received institutional review board approval from National Taiwan University Hospital (#201111054RIC). The patients in this study provided written informed consent for the publication of individual data and accompanying clinical images.
Short-segment fixation was defined as posterior stabilization enhanced by the pedicle screw and rod system (Diapason, Stryker Corp, Allendale, NJ; Aaxter Posterior Spinal System, Aaxter Co., Ltd., Taipei, Taiwan) and bone grafting one level above and one level below the injured vertebra. Abundant bone chips were packed meticulously into the void space of the collapsed vertebral body through the pedicle tract. Next, I-VEP (Aaxter Pillar Vertebral Spacer, Aaxter Co., Ltd.) that had been filled up with morcelized autologous cancellous bone chips were transpedicularly screwed into the posterior side of the vertebral body (Figures 1, 2 and 3). Bone-cement kyphoplasty (VCF-X, Bone Filler Delivery System, Central Medical Technologies, Inc., Taipei, Taiwan) was performed according to the standard balloon kyphoplasty procedure (Figure 4).
Radiographs of Patient 10 in Group I show a T12 vertebral compression fracture before the operation and at the one-year follow-up. a Preoperative sagittal view. b Preoperative anteroposterior view. c Postoperative lateral view. d Postoperative anteroposterior view.
Patient 5 in Group I is a 79-year-old man who was treated with short-segment fixation with I-VEP due to vertebral compression fracture of L2. a Lateral-view radiograph of Patient 5 in Group I shows an L2 vertebral compression fracture before the operation. b Anteroposterior view of the preoperative radiograph. c Lateral-view radiographs at the one-year follow-up. d Anteroposterior view at the one-year follow-up.
Patient 20 in Group I (70 years old female) with an L3 concave H-shaped burst fracture underwent I-VEP insertion at L3 combined with additional short segment fixation (L2-L4). a Preoperative CT, sagittal view. b Preoperative CT, axial view. c Lateral-view radiograph taken postoperatively. d Anteroposterior-view radiograph, taken postoperatively.
Radiographs of Patient 15 (76 years old male) in Group II show an L2 vertebral compression fracture before the operation and at the one-year follow-up. a Preoperative sagittal view. b Preoperative anteroposterior view. c Postoperative lateral view. d Postoperative anteroposterior view.
All patients assessed their pain before and 1 year after surgery using a 10-cm visual analogue scale (VAS). Imaging using a compression ratio of the anterior height (AH) of the fractured vertebra and local kyphotic deformity angle (KA) of the fractured vertebra was performed prior to the procedure and 12 months postoperatively (Figure 5). Measurements of AH and KA of the fractured vertebra in adjacent segments were radiographically documented just above or below the fracture level despite the presence of pedicle screws. During the course of treatment, symptomatic levels of VCF between T10 and L2 were defined as Level 2; those above T9 as Level 1; those below L3 as Level 3. On postoperative day 2 or 3, all patients were encouraged to carry a cane and wear a thoracolumbar brace while walking. This protection was supposed to be maintained for 3 months. After discharge, patients were regularly followed up and evaluated after 1 week, as well as after 1, 3, 6 and 12 months on the basis of VAS pain scores and radiographs.
Schematic diagrams of the radiographic measurements. a The anterior vertebral body height of the fractured vertebra (double arrow) is the actual height of the anterior cortex of the vertebral body as measured on the lateral radiograph. b Measuring on a lateral radiograph with modified Cobb method requires inferior endplates above the fractured vertebra for kyphotic angle measurement.
The data were evaluated using chi-square tests for gender and fracture, analysis of variance (ANOVA) for age, and analysis of covariance (ANCOVA) for the clinical outcomes. The level of statistical significance was set at p < 0.05.