Objective To review the research progress of the vacuum phenomenon in spine. Methods The recent articles about the vacuum phenomenon in spine were reviewed; the features of imaging and the cl inical correlation were summarized. Results The vaccum phenomenon has been described in every segment of the spine. This phenomenon occurs mostly to the disc space and represents a transparent area on radiograph. Conclusion The causes of the vacuum phenomenoninclude degeneration of the anatomic structures of spine, trauma, and other pathologic changes. The vacuum phenomenon has important diagnostic and cl inical significances.
Objective To evaluate the efficacy of percutaneous kyphoplasty (PKP) in hyperextension position for the treatment of osteoporotic vertebral compression fracture (OVCF) with vacuum phenomenon. Methods Between April 2004and August 2009, 35 patients who suffered from OVCF with vacuum phenomenon were treated with PKP in hyperextension position, 8 patients were excluded because of lost follow-up. In 27 follow-up cases, there were 9 males and 18 females with an average age of 75 years (range, 58-90 years) and with an average disease duration of 9.8 months (range, 2-17 months). One vertebral body was involved in 26 cases and 2 vertebral bodies were involved in 1 case. According to the imaging examination and Krauss et al. criterion, all patients were diagnosed as having vertebral vacuum phenomenon. Refer to the lateral X-ray views, the height and the kyphotic angle of the involved vertebral body were measured pre- and postoperatively. The surgical outcomes were evaluated by using visual analogue scale (VAS) and Oswestry disabil ity index (ODI) system. Results All operations were performed successfully with no severe compl ication. The mean follow-up of 27 patients was 32 months (range, 24-58 months). The mean cl inical heal ing time of OVCF was 4 months (range, 3-6 months). The VAS score, ODI system, anterior and medial height of involved vertebral body, kyphotic angle of involved vertebral body were improved significantly at 1 week after operation and at last follow-up (P lt; 0.05); there was no significant difference between at 1 week after operation and at last follow-up (P gt; 0.05). There was no significant difference in the posterior height of involved vertebral body among different postoperative time-points (P gt; 0.05). Asymptomatic cement leakage occurred in 3 patients. Adjacent vertebral fracture occurred in 1 patient at 7 months. Intravertebral vacuums showed a compact and sol id cement fill ing pattern. Conclusion PKP in hyperextension position can significantly rel ieve back pain, restore vertebral height, and correct local kyphosis in the treatment of OVCF with vacuum phenomenon.