[Vertebral body augmentation using a vertebral body stent]. / Augmentace obratlového tela vertebrálním stentem.

ABSTRACT

PURPOSE OF THE STUDY Osteoporotic vertebral fractures can be treated by minimally invasive percutaneous vertebral augmentation with bone cement using vertebroplasty or balloon kyphoplasty. Transcutaneous reduction and vertebral body stenting has been the most recent principle. In contrast to balloon placement in kyphoplasty, the stent remains in the vertebral body and supports both the vertebral body and cement filling. In this retrospective study we present the essential information on the method and our first results. MATERIAL AND METHODS: The method of vertebral body stent placement was used in 22 patients treated at 29 levels. Of these, 19 patients with 26 segments followed up for 3 months were evaluated. The group included 12 women and seven men with an average age of 68.3 years (12 to 83). The patients assessed their subjective complaints on the visual analogue scale (VAS) before surgery, and then at 1, 6 and 12 weeks post-operatively. The value of vertebral body reduction was obtained by measurement of anterior, middle and posterior vertebral body heights (AVBH, MVBH and PVBH, respectively) and a change in the vertebral body kyphotic angle (VBKA). RESULTS: Twenty-four vertebrae were treated for osteoporotic fracture and two as preventive stenting in metastatic breast cancer. In 24 fractures, the stents extended fully in 20 vertebrae, i.e., 40 stents. These fractures evidently were not older than 3 months. In four segments, a total of eight stents did not extend at all or did only slightly. The 20 stabilised vertebral bodies had an average AVBH value of 19.41 mm pre-operatively and that of 22.775 mm post-operatively, which is an average increase by 3.365 mm in absolute numbers and by 17.34 %. The average pre- and post-operative MVBH values were 16.625 mm and 23.065 mm, which was improvement by 6.41 mm or by 38.56 %. The average PVBH values pre- and post-operatively were 26.835 mm and 28.31 mm, which meant improvement by 1.475 mm or by 5.5 %. The average correction of the kyphotic angle was 4.58°, i.e., 35.2 %, from a VBKA of 11.71° pre-operatively to 7.13° post-operatively. There were five cases (22.7 %) of cement leakage, i.e., two of ventral leakage, one of lateral leakage, one of dorsal leakage through a canal left in the pedicle by cannula insertion, and a dorsal leakage in metastatic disease. No neurological findings were recorded. The average VAS scores were as follows 81.4 before surgery, 30.6 at 1 week, 16.3 at 6 weeks and 15.4 at 12 weeks after surgery. DISCUSSION: Two experimental and one clinical study on vertebral body stenting only have been available in the recent relevant literature. In comparison with their results as well as with those of previous reports on vertebroplasty and kyphoplasty, our results showed high quality fracture reduction in all vertebrae. The rapid decrease in pain intensity in our group is comparable with all available groups treated by any method of vertebral body augmentation by cement injection; and cement leakage was recorded in even fewer cases. CONCLUSIONS: The novel method of vertebral body stenting with cement augmentation provides a rapid pain relief, gives stability to fracture reduction and has a low rate of cement leakage. However, care must be taken not to indicate cases with a damaged posterior corticalis of the vertebral body.