A novel minimally invasive percutaneous facet augmentation device for the treatment of lumbar radiculopathy and axial back pain: technical description, surgical technique and case presentations. Larry T. Correspondence adress. The biomechanics of this Percudyn Interventional Spine; Irvine, CA system are distinct from that of other interspinous dynamic stabilization systems as it acts bilaterally directly within the middle column of the spine. Based on biomechanical evalution, the paired prosthesis supports, cushions, and reinforces the facet complexes by limiting both extension and lateral bending thereby maintaining central and foraminal volumes. METHODS: the Percudyn device consists of a pedicle anchor upon which sits a cushioning polycarbonate-urethane stabilizer that serves as a mechanically reinforcing stop between the inferior and superior articular facets.
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A novel minimally invasive percutaneous facet augmentation device for the treatment of lumbar radiculopathy and axial back pain: technical description, surgical technique and case presentations. Larry T. Correspondence adress. The biomechanics of this Percudyn Interventional Spine; Irvine, CA system are distinct from that of other interspinous dynamic stabilization systems as it acts bilaterally directly within the middle column of the spine.
Based on biomechanical evalution, the paired prosthesis supports, cushions, and reinforces the facet complexes by limiting both extension and lateral bending thereby maintaining central and foraminal volumes.
METHODS: the Percudyn device consists of a pedicle anchor upon which sits a cushioning polycarbonate-urethane stabilizer that serves as a mechanically reinforcing stop between the inferior and superior articular facets. Progressive onestep tubular dilation is then performed to secure a small disposable working portal.
Through this access, the Percudyn stabilizers are then placed over the wire and anchored bilaterally into the inferior pedicles of the degenerated motion segment. Each patient had significant relief of both his radiculopathy and axial back pain post-operatively and was discharged home within 18 hours without sequelae.
As the Percudyn device serves to reinforce the middle column directly at the level of the facet, it represents a new class of posterior motionpreserving stabilization which may serve to mitigate segmental axial back pain as has been described for other posterior dynamic stabilization systems. The degenerating lumbar spine is a major source of low back pain and disability in western industrial societies.
Both the degenerating disc and spondylolitic facet joints are thought to be potential pain generators in symptomatic patients with dysfunctional lumbar motion segments. Recently introduced dynamic stabilization devices have been designed to alleviate pain by purportedly stiffening or supporting the motion segment in attempt to restore the native biomechanical neutral zone.
These "dynamic stabilizers" have typically required open exposures with concomitant stripping of the very musculature and ligaments that maintain the intrinsic stability of the spine.
We describe a new type of posterior facet augmentation device Percudyn; Interventional Spine Inc; Irvine, CA that serves to stabilize the middle column of the spine through a novel bilateral mechanism. The prostheses are delivered percutaneously into the bilateral superior articular processes SAP of the inferior vertebral body VB where they serve as a mechanical stop to the inferior articulating process IAP coming down from the level above thereby directly augmenting the stiffness of the facet column.
From a biomechanical perspective, the Percudyn serves primarily to limit extension and lateral bending of the treated lumbar level, therefore also preventing further compression of the spinal canal, neural foramen, and posterior disc.
As compared to the majority of other interspinous devices, the Percudyn is unique in that two key aspects: 1 It is truly minimally invasive as can be placed completely percutaneously without the need for any muscle or ligament stripping, and 2 It acts to stabilize the middle column bilaterally as it acts in both facets thereby having effect in lateral bending as well.
In this technical note, we describe the surgical procedure for implantation of the paired Percudy prosthesis for treatment of degenerative lumbar disc disease. Once the induction of general or local anesthesia has been achieved, the patient is positioned prone on a Jackson or other compatible radiolucent operative table. Every effort should be made to maintain a reasonable lordosis at the treated level and to avoid kyphogenic frames or positioning. Under fluoroscopic guidance, the pedicles of the inferior body of the treated level are visualized and appropriate small 1cm incisions marked.
The incision site is localized and marked with fluoroscopy from the posterior side with the image exactly on top of pedicle where the device will be implanted.
An approximately 15mm incision is made with a 11 blade through skin and fascia. An access needle is then introduced through this incision through the musculature under fluoroscopy towards the fluoroscopic pedicle target. The tip of the needle is walked along the facet and docked ensuring that it is exactly positioned at the bottom of the IAP approximately in the middle of the oval fluoroscopic pedicle shape Figure 1A , 1B.
After verification of the needle docking position, the targeting needle is inclined 10 degrees medially and 10 degrees caudally to obtain a trajectory that will lie within the pedicle but also maintain a near orthogonal orientation to the face of the SAP and the plane of the facet joint itself Figure 1C. The access needle is then advanced through the pedicle into the posterior aspect of the vertebral body under biplanar fluoroscopic guidance.
The central core of the access needle is then exchanged via Seldinger technique for a Kirschner-wire which is then advanced slightly further into the vertebral body Figure 1D. A proprietary one step "Teleport" sequential dilator is then introduced down to the pedicle entry point along the K-wire.
The novel mechanism of this introducer allows for efficient serial dilation without the need for multiple tube exchanges to rapidly establish the small working corridor to each pedicle Figure 2A.
The drill is then retracted, and the pathway prepared with a 4mm tap Figure 2C. A favorable countersink at the level of the SAP and facet joint is then created with a 10 mm cannulated ball-shaped rasp to establish a seat for the polycarbonate PCU head of the Percudyn prosthesis bilaterally Figure 2D. A hollow 4. The unique design of the screwdriver allows for disengagement of the anchor once it has been fully seated in the SAP to prevent over countersinking.
The cannulated polycarbonate - urethane stabilizer PCU head is then introduced over the wire down to the prepared bony seat Figure 4A , 4B , 4C. After fluoroscopic confirmation of the implant position, the PCU head is then impacted and locked to the 4.
As the head is locked and compressed, the polycarbonate ring radially expands thereby further seating within and distracting the facet joint. The same series of steps is then repeated on the contralateral side Figure 4D. After the intial, simultaneous placement of bilateral Percudyn devices can be readily achieved in very rapid fashion.
This year-old male presented with a 5 year history of central mechanical low back pain and lumbar radicular pain. The pain was greater on the left than on the right. His pain was exacerbated by a motor vehicle accident 15 months prior to admission. The pain was exacerbated by mechanical activities such as standing and walking and was relieved by sitting or lying down. He failed a 6-month course of conservative management that consisted of physical therapy as well as multiple injections including facet blocks that provided him only with short-term relief.
His pain not well relieved by Vicodin and muscle relaxants. For that reason he elected to undergo bilateral L5-S1 minimally invasive lamionotomy, medial facetectomy, and foraminotomy for decompression of the neural elements and dynamic posterior stabilization of L and L5-S1 with the Percudyn prostheses Figure 5B , 5C. The decompression required 45 minutes and the implantation an additional 35 minutes with a total blood loss of 20cc and a hospital stay of 18 hours. He tolerated the procedure well and had excellent relief his radiculopathy as well as improvement of the mechanical central pain as well.
He has returned to work and full activity with only intermittent use of non-steroidal anti-inflammatory for pain Figure 5. He had attempted conservative management for five months, which included physical therapy and injections without relief.
His pain was mostly located in the lower lumbar area as a band with radiation to the right side buttock and leg in a L5 distribution. Where as sitting and bending to the left eased his radiculopathy, it also greatly exacerbated his central axial low back pain. He underwent a right-sided minimally invasive microsurgical laminotomy and microdiscectomy via a tubular approach for treatment of his radiculopathy.
As he had a significant component of mechanical back pain, we discussed with him the various options including fusion, artificial disc placement, and dynamic posterior stabilization. Whereas he did not wish to have fusion, he also did not feel that he could tolerate his mechanical back pain at the present level.
He thus ultimately chose to have bilateral L posterior percutaneous Percudyn dynamic stabilization in addition to his decompression Figure 6C , 6D. The decompression and stabilization required 40 and 30 minutes respectively with minimal blood loss and a five hours stay in the hospital. His radiculopathy resolved early on postoperatively with a good response in his back pain as well.
This year-old male had low back pain for one year superimposed upon which he then developed new left sided S1 radicular pain and mild plantar flexion weakness with tension signs. The radicular pain was far more debilitating than his chronic low back pain causing him to be unable to work with difficulty ambulating. Both his leg and back pain were worsened by sitting and standing and relieved with lying down.
Preoperatively, he required 2 to 4 vicodin tablets per day in conjunction with 2 tablets of Flexeril to manage his pain. In an effort to decompress his right S1 nerve as well as to alleviate his significant axial mechanical back pain, he elected to undergo a left L5-S1 minimally-invasive tubular microsurgical decompression and microdiscectomy with placement of bilateral L5-S1 PercuDyn stabilizers Figure 7A , 7B.
Total surgical time was 1 hour and 10 minutes with minimal blood loss and no complications. Post-operatively, his radicular pain completely resolved and he was discharged 4 hours later. By his initial 10 day postoperative visit, he was able to discontinue all of his narcotic medications and took only a two ibuprofen mg tablets once to twice a day.
Traditionally, decompression, stabilization and the correction of existing deformity have been the hallmarks of surgical management of low back pain or lumbar instability. However, there has not been a corresponding improvement in clinical outcomes despite a high fusion rate has been achieved with the advances in biomedical technique and instruments Some people have chronic back pain but their imaging studies did not reveal evidences of instability or neurologic compression.
Degenerative change of the spine has been considered an important source of low back pain 3. Spinal degeneration may include disc degeneration, facet joint osteoarthritis, vertebral body degeneration and ligament degeneration 4.
However, initial degenerative change of the spine usually begins with intervertebral disc degeneration especially from nucleus pulposus and the intervertebral disc is considered to be a predominant source of low back pain by many clinicians and researchers 5, 7. The magnitude, duration and frequency of load and pressure are all related to disc degeneration. Excessive load causes loss of disc height, degradation of extracellular matrix, increased apoptosis and disorganization of the cellular architecture 8.
Diminished blood supply to the intervertebral disc was considered to initiate tissue breakdown and this may start as early as in the second life decade 7,9. In this degenerative process, dehydration of nucleus and weakness of annulus develop which causes loss of its resistance to rotation and translational forces 8.
With advancing degeneration, the proportion of load transmitted through the nucleus decreases but through the posterior elements increases 10, This result was similar to Yang and King's study that facet load for segments with degenerated discs increases significantly Thus subsequent degeneration of the facet joints usually follows disc degeneration or develops concomitantly which may in turn cause low back pain 12,14, Within the confines of degenerative disc disease, there is a significant gap between the conservative and total disc replacement.
The treatment options may vary from activity modification, nonsteroidal anti-inflammatory drugs, physiotherapy, epidural injection, IDET or fusion. Before emergence of "dynamic stabilization" concept, those who failed to response to conservative treatment could only choose rigid metallic lumbar fusion or motion-preserving arthroplasty.
However, a considerable amount of morbidity and complications after fusion surgery have being reported gradually 16, In addition, the elimination of mobility at the fused level may cause adjacent segments degeneration which usually requires re-interventions The artificial disc replacement is a good option to degenerative disc disease treatment. It can not only preserve the motion of operated segment but also reduce the mechanical forces transmitted to the adjacent segments 22, Nevertheless, this set of devices requires good facets, posterior ligaments, and muscular structures that limited its application in those who have facet hypertrophy Unfortunately, the degeneration of discs and facet joints always develops simultaneously.
As a consequence, some investigators explored alternative approaches to stabilize the lumbar spine. One important concept is "dynamic stabilization" which adopts semirigid stabilization to restrict motion in the direction or plane that produced pain, or painful motion, but would otherwise allow a full range of motion and therefore maintain function 25, It would ideally improve the movement and the load transfer of a spinal segment but without the intention of fusion.
So far, a lot of posterior dynamic stabilization systems have been developed in the literature. These can be classified into three main categories. The goal of dynamic stabilization is to induce a regression of the degenerative process in the pathologic disc structure. Animal models with controlled dynamic disc distraction on degenerated intervertebral discs suggest that disc regeneration can be induced.
The decompressed discs showed signs of tissue recovery on a biologic, cellular, and a biomechanical level Guehring reported signs of rehydration of the nucleus on MRI after distraction of rabbit intervertebral disc Lafage and Gangnet et al.
Radiculopathy (Pinched Nerve)
Radiculopathy is a pinched nerve in the spine. It occurs with changes in surrounding bones and cartilage from wear and tear, or from injury. These changes may cause pressure on a nerve root. A nerve root is the part of each spinal nerve that exits your spinal cord and goes through an opening in your spine. When your nerve roots are compressed, they may become inflamed, causing numbness, weakness, and pain. Timely and appropriate treatment can reduce these symptoms. Symptoms of radiculopathy can range from mild to severe.
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Radiculopathy , also commonly referred to as pinched nerve , refers to a set of conditions in which one or more nerves are affected and do not work properly a neuropathy. This can result in pain radicular pain , weakness, numbness, or difficulty controlling specific muscles. In a radiculopathy, the problem occurs at or near the root of the nerve, shortly after its exit from the spinal cord. However, the pain or other symptoms often radiate to the part of the body served by that nerve. For example, a nerve root impingement in the neck can produce pain and weakness in the forearm. Likewise, an impingement in the lower back or lumbar - sacral spine can be manifested with symptoms in the foot. The radicular pain that results from a radiculopathy should not be confused with referred pain , which is different both in mechanism and clinical features.