31: Interspinous Process Motion-Sparing Implant

Procedure 31 Interspinous Process Motion-Sparing Implant



Christopher F. Wolf, Mark M. Mikhael, Arya Nick Shamie



Indications




image Lumbar stenosis at one or two levels


• Central stenosis

• Lateral recess stenosis

• Foraminal stenosis

• Facet hypertrophy and cyst formation

image Patient must report a resolution of symptoms when seated or flexed forward (i.e., “shopping cart” sign) when upright.



Indications Pitfalls




• Symptoms unresolved with lumbar flexion


• Axial back pain as the main complaint (versus buttock and/or leg pain)


• Osteoporosis with recent history of fragility fracture (severe osteoporosis)


• Spondylolisthesis greater than 25% on static or dynamic radiographs


• Significant scoliosis (greater than 25 degrees at the level of stenosis)


• Ankylosis of the involved segment



Indications Controversies




• “Mild to moderate” stenosis indication for ISP implantation refers to patients’ symptoms (able to walk at least 50 feet), not the MRI findings.


• Although studies show that claudication in patients with severe stenosis (on magnetic resonance imaging [MRI]) can be helped with ISP implants, some surgeons reserve this device for mild to moderate stenosis (on MRI) patients only.

• Three-level implantation of the device is not currently approved. Some surgeons have had success with treatment of three-level stenosis with ISP implantation.


Figures 31-3, 31-5, 31-6, and 31-8 © 2011 Medtronic Spine, LLC. Used with permission.



Examination/Imaging




image Standing anteroposterior (AP), lateral (neutral, extension [left] and flexion [right]) views (Figure 31-1)


• If patient has grade 2 spondylolisthesis on static or dynamic films, that condition is considered a contraindication to the interspinous process (ISP) procedure.

image MRI with axial, sagittal, and coronal imaging to assess disk herniation, canal stenosis, and Modic changes (Figure 31-2)


image

FIGURE 31-1


image

FIGURE 31-2



Treatment Options




• Nonsurgical management, that is, physical therapy, epidural steroid injections, and so forth


• Laminectomy without fusion or with fusion in setting of spondylolisthesis


• Anterior versus lateral interbody fusion alone with indirect decompression


• Disk arthroplasty



Surgical Anatomy




image Midline skin incision with bilateral fascial incision exposing the inferior and superior aspects of the spinous processes at the selected interspinous segment (Figure 31-3)


image Careful preservation of the supraspinous ligament


image Avoiding disruption of the facet joint anatomy


image

FIGURE 31-3



Positioning




image Lateral positioning on radiolucent table (Figure 31-4)


image Prone positioning on a Jackson table with a Wilson frame for maximal flexion at the index level


image

FIGURE 31-4



Positioning Pearls




• Radiolucent table


• Ensure patient positioning with hips and knees flexed to accentuate lumbar flexion; this position will splay the spinous processes, aiding in ease of insertion of the ISP device.

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Aug 28, 2016 | Posted by in ORTHOPEDIC | Comments Off on 31: Interspinous Process Motion-Sparing Implant

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