Lumbar Disc Replacements and Motion Preservation Devices
Lumbar Disc Replacements and Motion Preservation Devices
The gold standard of surgical treatment for DDD of the lumbar spine is fusion, which eliminates motion in the spine. There are three high-quality, randomized, controlled studies that have evaluated spinal fusion as compared with nonsurgical treatment in the setting of chronic low back pain and DDD. None of them provide definitively favorable results for surgical intervention. Fritzell et al. compared lumbar fusion with nonsurgical treatment. The nonsurgery group's treatment modalities focused on physical therapy, patient education, and alternative modalities, such as the transcutaneous electrical nerve stimulation units, acupuncture, and injections. The results indicated that in properly selected patients surgical treatment of severe chronic low back pain provides improved functional results and a higher return to work than nonsurgical treatment. Brox et al. and Fairbank et al. compared surgical lumbar fusion and intensive rehabilitation with intensive cognitive behavior therapy. Both of these large randomized controlled studies found nearly equivalent outcomes between the surgical and nonsurgical groups.
Total disc replacement (TDR) and dynamic stabilization offer alternatives to fusion and maintain the spine's function of protection, motion, and load bearing. Clinicians are hopeful that these motion preservation devices will prevent or slow the sequelae of adjacent-level degeneration (ALD).
It should be noted that patient selection is different for motion preservation than for fusion. Indications for fusion in lumbar DDD include: (1) fusion at the time of decompression in patients with spondylolisthesis or scoliosis; (2) fusion secondary to iatrogenic destabilization including pars fracture or spondylolisthesis; (3) postoperative recurrence of stenosis or disc herniation at the same level as a previous surgery; (4) Incapacitating and debilitating mechanical back pain; and (5) symptomatic ALD. Motion preservation and specifically TDR have strict patient selection criteria. In the US, lumbar TDR is approved for treatment of isolated discogenic back pain without instability. Surgery is typically reserved for one-level disease in young patients (age 18–60 years) with objective evidence of DDD on MRI or CT for which at least 6 months of conservative treatment has failed. Provocative discography can be used to verify if adjacent segments are normal. Exclusion criteria include central and/or lateral recess stenosis, facet arthropathy, spondylolysis or spondylolisthesis, radiculopathy secondary to herniated nucleus pulposus, scoliosis, osteoporosis, chronic steroid use, fracture, pregnancy, or infection.
Complications from fusion vary widely depending on the technique used to achieve fusion, and there are many different fusion techniques. It is imperative that surgeons be cognizant of all potential complications of any surgical technique before one-level surgical intervention. As cited in detail later, motion preservation devices have a wide spectrum of complications that is dependent on both surgical technique for implantation and the implant.
Surgical Treatment
The gold standard of surgical treatment for DDD of the lumbar spine is fusion, which eliminates motion in the spine. There are three high-quality, randomized, controlled studies that have evaluated spinal fusion as compared with nonsurgical treatment in the setting of chronic low back pain and DDD. None of them provide definitively favorable results for surgical intervention. Fritzell et al. compared lumbar fusion with nonsurgical treatment. The nonsurgery group's treatment modalities focused on physical therapy, patient education, and alternative modalities, such as the transcutaneous electrical nerve stimulation units, acupuncture, and injections. The results indicated that in properly selected patients surgical treatment of severe chronic low back pain provides improved functional results and a higher return to work than nonsurgical treatment. Brox et al. and Fairbank et al. compared surgical lumbar fusion and intensive rehabilitation with intensive cognitive behavior therapy. Both of these large randomized controlled studies found nearly equivalent outcomes between the surgical and nonsurgical groups.
Total disc replacement (TDR) and dynamic stabilization offer alternatives to fusion and maintain the spine's function of protection, motion, and load bearing. Clinicians are hopeful that these motion preservation devices will prevent or slow the sequelae of adjacent-level degeneration (ALD).
It should be noted that patient selection is different for motion preservation than for fusion. Indications for fusion in lumbar DDD include: (1) fusion at the time of decompression in patients with spondylolisthesis or scoliosis; (2) fusion secondary to iatrogenic destabilization including pars fracture or spondylolisthesis; (3) postoperative recurrence of stenosis or disc herniation at the same level as a previous surgery; (4) Incapacitating and debilitating mechanical back pain; and (5) symptomatic ALD. Motion preservation and specifically TDR have strict patient selection criteria. In the US, lumbar TDR is approved for treatment of isolated discogenic back pain without instability. Surgery is typically reserved for one-level disease in young patients (age 18–60 years) with objective evidence of DDD on MRI or CT for which at least 6 months of conservative treatment has failed. Provocative discography can be used to verify if adjacent segments are normal. Exclusion criteria include central and/or lateral recess stenosis, facet arthropathy, spondylolysis or spondylolisthesis, radiculopathy secondary to herniated nucleus pulposus, scoliosis, osteoporosis, chronic steroid use, fracture, pregnancy, or infection.
Complications from fusion vary widely depending on the technique used to achieve fusion, and there are many different fusion techniques. It is imperative that surgeons be cognizant of all potential complications of any surgical technique before one-level surgical intervention. As cited in detail later, motion preservation devices have a wide spectrum of complications that is dependent on both surgical technique for implantation and the implant.
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