Dural Laceration Resulting in the Formation of Syringomyelia Caused by a Loosened Hydroxyapatite Intraspinous Spacer after Spinous Process-splitting Laminoplasty.

A 63-year-old man was admitted in our hospital with the chief complaint of upper limb numbness 3 years after undergoing spinous process-splitting laminoplasty (C3-C7) in another hospital. The hydroxyapatite spacers used for the laminoplasty had dislocated, resulting sensory disorders of the upper extremities. Additionally, loosened hydroxyapatite intraspinous spacers and syringomyelia were confirmed. A revision operation was performed, during which the C5 spacer was observed to have dislodged into the spinal canal, and a dural membrane defect, arachnoid membrane tear, cerebrospinal fluid leakage, and marked adhesion change were observed. The adhesion was exfoliated as far as possible; moreover, to prevent the reflux of syringomyelia, a syrinx-subarachnoid shunt (SS shunt) was placed. Although there was concern of further adhesion by putting foreign matter, SS shunt indwelling was chosen to obtain sure disappearance of syringomyelia. The postoperative course was uneventful. A gradual improvement in the upper limb numbness was observed without a recurrence of syringomyelia at 9 years of follow-up.

Percutaneous vertebroplasty using hydroxyapatite blocks for the treatment of vertebral body fracture.

Vertebroplasty with hydroxyapatite blocks through a modified percutaneous approach was used to treat 30 patients with vertebral body fractures in 32 vertebral bodies between February 2003 and March 2007. The mean follow-up period was 16.6 months. The pain associated with this procedure, effects on adjacent vertebral bodies, and other complications were evaluated. The rate of recollapse after vertebroplasty was examined in 26 patients with 26 vertebral bodies treated and followed up for more than 3 months. Mean time of operation was 57 minutes and mean number of blocks used per vertebral body was 104. The mean visual analogue scale score was 7.0 preoperatively and 1.6 postoperatively. The mean decline in postoperative vertebral body height was 13%. New vertebral body fractures occurred postoperatively in 3 vertebral bodies in 2 patients. Leakage of blocks outside the vertebral body occurred in 2 patients during the operation, and after the operation in one patient, and the hydroxyapatite plug broke postoperatively in one patient. Hydroxyapatite blocks yielded good pain relief comparable to bone cement, with no serious complications such as a pulmonary embolism or leakage into the spinal canal, and are effective for percutaneous vertebroplasty.