[Percutaneous interspinous dynamic stabilization (in-space) in patients with degenerative disease of the lumbosacral...

Interspinous spacers are supposed to reduce the segmental extension with a decrease in the expansion of yellow ligaments into the spinal canal, thus avoiding the dynamic narrowing of the spinal canal and compression of nerve roots. The aim of this study was to evaluate clinical outcomes and post-operative complications during one year in patients mostly having suffered from spinal stenosis and treated by In-Space interspinous spacer (Synthes, USA).

A total of 25 patients aged between 25 and 73 (average age 52.6) years, including 18 males and 7 females, with degenerative disease of the lumbosacral spine were indicated for surgery and prospectively followed up. The patients were operated on under general anaesthesia in the prone position, using a minimally invasive lateral percutaneous approach, under fluoroscopic control. The ODI and VAS values as well as X- rays (Range Of Motion and Sagittal angle of the operated segment) 6 and 12 months after the surgery were compared to each other and to those before surgery. The results were statistically analyzed.

The average ODI of the group was 47.2% before surgery and 17.48% 6 months (22.76% 12 months) after surgery, showing a statistically significant improvement by 63% (52% after 12 months). The average VAS of the group was 6.64 points before surgery and 2.96 points 6 months (2.8 points 12 months) after surgery, which showed a statistically significant improvement by 55.4% after 6 months (57.8% after 12 months) when compared to preoperative status. After surgery the lordotic sagittal angle remained in all cases; one year after surgery the angle increased due to the slight sinking of some implants. The extent of segmental motion was minimally changed (6.1° 6 months and 7.24° 12 months after surgery). No serious complications occurred. The effect of interspinous implants proved insufficient in two cases (one year and two years after surgery) and conversion to arthrodesis or decompression was performed.

1. Percutaneous, minimally invasive insertion of an In-Space interspinous spacer is an effective and safe method of dynamic stabilization not accompanied by any serious complications. 2. ODI improved by 63% 6 months after surgery with a decrease in this effect 12 months after surgery. VAS for axial and radicular pain, as reported by patients, improved on average by 55.4% 6 months and by 57.8% 12 months after surgery. 3. In all cases, the lordotic sagittal angle remained after surgery and the extent of segmental motion from flexion to extension was minimally changed.