Augmentation of (pedicle) screws with calcium apatite cement in patients with severe progressive osteoporotic spinal deformities: an innovative technique

Screw augmentation with calcium apatite cement (CAC) was used in seven patients with a progressive osteoporotic spinal deformity. Thirty-nine spinal segments (64 screws) were augmented: 15 anteriorly (three patients) and 24 posteriorly (five patients). Dorsally, hemilaminectomy was performed at the level of all augmented screws to rule out CAC leakage. Autogenous bone graft was applied in all patients to induce fusion. Screw augmentation failure occurred in only one patient: 1 of the 16 ventral augmented screws (5.5%) was still loose after the augmentation procedure. In three other patients, 4 out of 48 augmented dorsal screws (5.5%) showed CAC leakage at the pedicle corpus vertebra level. Pedicle wall damage was present at two levels, while at two other levels no wall damage was found during visualization. No CAC-related complications were observed perioperatively. No implant migration was observed, and fusion was observed in all cases at follow-up examination performed at a mean of 32 months after surgery. Received: 29 December 1999 Revised: 30 March 2000 Accepted: 7 April 2000