Interspinous posterior devices: What is the real surgical indication?

Abstract

Interspinous posterior device (IPD) is a term used to identify a relatively recent group of implants used to treat lumbar spinal degenerative disease. This kind of device is classified as part of the group of the dynamic stabilization systems of the spine. The concept of dynamic stabilization has been replaced by that of dynamic neutralization of hypermobility, with the intention of clarifying that the primary aim of this kind of system is not the preservation of the movement, but the dynamic neutralization of the segmental hypermobility which is at the root of the pathological condition. The indications for the implantation of an IPD are spinal stenosis and neurogenic claudication, assuming that its function is the enlargement of the neural foramen and the decompression of the roots forming the cauda equina in the central part of the vertebral canal. In the last 10 years, use of these implants has been very common but to date, no long-term clinical follow-up regarding clinical and radiological aspects are available. The high rate of reoperation, recurrence of symptoms and progression of degenerative changes is evident in the literature. If these devices are effectively a miracle cure for lumbar spinal stenosis, why do the utilization and implantation of IPD remain extremely controversial and should they be investigated further? Excluding the problems related to the high cost of the device, the main problem remains the pathological substrate on which the device is explicit in its action: the degenerative pathology of the spine.

Keywords: Interspinous posterior device; Interspinous fusion device; Interspinous distraction; Motion preservation surgery; Spine surgery; Minimally invasive surgery

Core tip: If interspinous posterior devices are effectively a miracle cure for lumbar spinal stenosis, why does their use and implantation remain extremely controversial and should they be investigated further? The aim of this editorial is to analyze and underline why these devices have poor outcomes, focusing on a biomechanical point of view, trying to define indications and limits. Is important to underline that these implants must not become a trend but only a weapon in the surgeon’s hands and, as with every weapon, is extremely dangerous in the wrong hands. So the spinal surgeon is the only one who can decide when to use it and must know the effects of this weapon in detail to use it correctly with no damage for the patient.