Abstract
Introduction
Low-back pain syndrome is, up to date, one of the most common cause of inability, especially for young-adult people. In 20% of cases, patients have a degenerative disc disease associated with radiculopathy due to neuroforamen diameter reduction and lumbar soft-stenosis. Interspinous devices were extensively used in the treatment of this pathology, with different outcomes.
Material and Methods
An observational study was conducted comparing the interspinous device implant only, according to the standard technique, versus the devices implant together with a supraspinous ligament removal. Since April 2012, 81 patients with low-back pain and foraminal “soft” stenosis were enrolled and divided into two groups, homogeneous for age, sex, and disease severity (clinically and instrumentally assessed). Before surgery, all patients were subjected to medical therapy for at least 6 months without any clinical benefit. A total of 39 patients (group A, control) underwent interspinous devices implant only, according to the standard technique and 42 patients (group B) underwent device implant and supraspinous ligament removal. A clinical follow-up was performed at month 1, 3, 6, 12, and 24 by mean of visual analog scale (VAS), neurogenic claudication outcome score (NCOS), and Oswestry low back pain disability questionnaire (OLBPDQ). A radiographic control was obtained at month 1 and 6 (dynamic radiographic studies included). A MRI was done at month 6. The data were analyzed by mean of the Kaplan–Meier curve (results yielding a p value < 0.05 were considered statistically significant).
Results
Until month 12, slight differences in VAS, NCOS, and OLBPDQ values were noticed between the two groups, but these scores was significantly higher in group B at month 24. Furthermore, radiographic evaluation showed a more significant neural foramina height recovery (mean value: 23 ± 3% vs. 41 ± 3%, respectively, in groups A and B). Although the supraspinous ligament is removed, there is not iatrogenic instability risk, because the device produces an immediate mechanical stability and a consequent intervertebral fusion. At follow-up there were no “fixation failure” and none patient underwent revision surgery. The standard technique provides the intraspinous ligament incision only and the devices positioning in the space between the spinous processes. In our opinion, this approach represents only a partial approach. Although the device implant is useful for radiculopathy resolution, usually low back could decrease, but in many cases only at the beginning. In fact the device may produce a supraspinous ligament extreme elongation, through to the intervertebral distraction. The nociceptors are abnormally stimulated and the back pain can reappear or in some cases persist.
Conclusion
This approach is able to definitively resolve both radiculopathy and low-back pain. This is an effective technique in terms of safety and efficacy, capable to provide a structural and functional correction, without back pain persistence risk, due to supraspinous ligament extreme elongation.