Effect of a novel interspinous implant on lumbar spinal range of motion

Abstract

Interspinous devices have been introduced to provide a minimally invasive surgical alternative for patients with lumbar spinal stenosis or foraminal stenosis. Little is known however, of the effect of interspinous devices on intersegmental range of motion (ROM). The aim of this in vivo study was to investigate the effect of a novel minimally invasive interspinous implant, InSwing Ò , on sagittal plane ROM of the lumbar spine using an ovine model. Ten adolescent Merino lambs underwent a destabilization procedure at the L1-L2 level simulating a stenotic degenerative spondylolisthesis (as described in our earlier work; Spine 15: [571][572][573][574][575][576] 1990). All animals were placed in a side-lying posture and lateral radiographs were taken in full flexion and extension of the trunk in a standardized manner. Radiographs were repeated following the insertion of an 8-mm InSwing Ò interspinous device at L1-L2, and again with the implant secured by means of a tension band tightened to 1 N/m around the L1 and L2 spinous processes. ROM was assessed in each of the three conditions and compared using Cobb's method. A paired t-test compared ROM for each of the experimental conditions (P \ 0.05). After instrumentation with the InSwing Ò interspinous implant, the mean total sagittal ROM (from full extension to full flexion) was reduced by 16% from 6.3°to 5.3 ± 2.7°. The addition of the tension band resulted in a 43% reduction in total sagittal ROM to 3.6 ± 1.9°which approached significance. When looking at flexion only, the addition of the interspinous implant without the tension band did not significantly reduce lumbar flexion, however, a statistically significant 15% reduction in lumbar flexion was observed with the addition of the tension band (P = 0.01). To our knowledge, this is the first in vivo study radiographically showing the advantage of using an interspinous device to stabilize the (2009( ) 18:696-703 DOI 10.1007 spine in flexion. These results are important findings particularly for patients with clinical symptoms related to instable degenerative spondylolisthesis.Eur Spine J

Interspinous Implant with Unilateral Laminotomy for Bilateral Decompression of Degenerative Lumbar Spinal Stenosis in Elderly Patients

“…1) Restoring the posterior tension band by retightening the posterior elements in the vertebral body and not touching the supraspinous ligament reduce the posterior enfolding effect of the ligament flavum, and reload the disc in a more physiological pattern during motion. 2) Unloading the facet joint decreases the level of facetogenic pain and allows the repair and restorative mechanisms of the body to reduce the degree of inflammation 7,16,[19][20][21][22]25) . Radiologically, DIAM would increase the posterior disc height, prevent or reduce the degree of spondylolisthesis, and correct the lordosis with kyphosis.…”

Lumbar intervertebral disc allograft transplantation: long-term mobility and impact on the adjacent segments

“…Functional flexion-extension radiography is commonly used clinically for the assessment of vertebral stability and mobility. The second limitation in this study is that the full-flexion and -extension positions of the goats were made passively under general anaesthesia, although this method has been accepted also by other researchers [6,14]. The third limitation is that the goats are quadruped and do not reproduce the exact anatomy, loading and intradiscal pressures of the lumbar spine in the humans [25,26].…”

“…Radiographs at these positions were also taken in the five goats of untreated control after follow-up for 12 months. As shown in Fig.1A-B, full flexion was achieved by securing a rope above the carpus of forelimbs and the tarsus of hindlimbs by binding the four limbs together with the lumbar spine held in the maximally flexed position [6,14]. For the extension radiograph, the goat was placed supine with a customized bolster placed directly under the operated segment with both forelimbs tied to one end of the table while both hindlimbs were tied to the opposite end, according to the previous literatures [6,14].…”

Chirurgie du rachis du sujet âgé : radiculalgie, canal rétréci : particularités, enjeux, résultats ?

“…Lorsqu'elles sont tout à fait ouvertes, la pression verticale des apophyses épineuses sur ces ailettes verrouille le dispositif en place. L'intervention déstabilisatrice a entraîné une augmentation de la mobilité du segment qui n'était pas modifiée par l'insertion de l'implant seul ; cependant, l'addition du laç age a permis de réduire cette mobilité anormale de manière très significative [52].…”