Four spine surgeons discuss the devices and techniques that will have a significant effect on patient care.
Ask Spine Surgeons is a weekly series of questions posed to spine surgeons around the country about clinical, business and policy issues affecting spine care. We invite all spine surgeon and specialist responses.
Next week's question: What can spine surgeons do to ensure their skill-set remains sharp?
Please send responses to Anuja Vaidya at avaidya@beckershealthcare.com by Wednesday, April 3, at 5 p.m. CST.
Question: What devices currently on the market do you think have the most potential to improve spine care?
Brian R. Gantwerker, MD. Founder of the Craniospinal Center of Los Angeles: I believe arthroplasty remains an important adjunct in care. They have their place, and when not over-used and [only] used in reasonable situations, are very valuable. It allows patients to theoretically delay or perhaps avoid further surgery. The newer expandable lateral lumbar cages, I think are very exciting and make it easier to get sagittal balance in certain cases and will likely result in fewer and fewer flat backs. Robots, I think, will find their place and can really improve accuracy — in theory — but we should not forget that humans are still, and fallibly so, running them. Intraoperative imaging and guidance have improved by leaps and bounds, and certain lightweight and super-exciting technologies have come to the fore to spare everyone in the room from the normally prodigious amounts of radiation.
Alden Milam, MD. Spine Surgeon at OrthoCarolina (Charlotte, N.C.): Hopefully, patient-specific 3D printing, which has already started, will grow in its application. The idea of implants tailored for the nuance of patient anatomy, bone density and/or goals of surgery (such as sagittal or coronal correction) is exciting as a new frontier for spinal implants.
Issada Thongtrangan, MD. Orthopedic Spine and Neurosurgeon at Minimally Invasive Spine (Phoenix): In my opinion, minimally invasive via endoscopic approaches will gain more popularity in the next five to 10 years, similar to the tubular-based retractor in the past 15 to 20 years [where] more and more evidence has shown excellent patient outcomes and superior-to-traditional technique. Endoscope brings the minimally invasive spine surgery to the next level and can be utilized in almost all aspects of cervical and lumbar spine pathologies. I also predict that robotic and navigation-based surgery will prove their value in spine arena, and it could replace 2D images such as fluoroscopic C-arm in the future. 3D printed devices and advancement in surface technologies will also enhance fusion outcomes.
Jason M. Cuéllar, MD, PhD. Assistant Professor in the Department of Orthopaedic Surgery at Cedars-Sinai Medical Center (Los Angeles): Artificial disc replacement is currently gaining in popularity and has the greatest potential to improve spine care across the globe as its utilization becomes more popular and its indications expand. There are currently two devices available for use in the United States for the lumbar spine (ActivL and ProDisc-L) and seven devices for use in the cervical spine (Prestige-LP, Prestige ST, ProDisc-C, Secure-C, MobiC, Bryan and PCM). There are several currently in the pipeline for approval, and the much-awaited M6 cervical implant from Orthofix has just recently gained FDA approval for single-level use and will be available for use this summer starting in select sites. The Prestige-LP from Medtronic and MobiC from LDR currently have FDA approval for two-level use.
We now have a growing body of level 1 evidence demonstrating the long-term superiority of artificial disc replacement compared to fusion, particularly when performed at two levels. The seven-year Prestige-LP study1 demonstrated that there was more than a three-fold higher rate of re-operating following two-level anterior cervical discectomy and fusion when compared to the two-level cervical artificial disc replacement group. This difference is even more dramatic for the 10-year data, which is in the process of being published. In my own practice, I rarely find the need to perform fusion in the cervical spine, as artificial disc replacement can usually be performed instead. Artificial disc replacement allows for rapid postoperative recovery with no need for cervical immobilization or monitoring for pseudarthrosis. As we continue to push the indications, we are finding that completely collapsed disc spaces and mild or moderate facet arthropathy does not necessarily need to be a contraindication.
Artificial disc replacement in the lumbar spine has also demonstrated excellent long-term success, although its history was somewhat tainted by the failure rate of the Charite implant. The ProDiscL has been studied extensively and we now have excellent data demonstrating reduced rates of adjacent-segment degeneration after lumbar disc replacement compared to fusion2, with similar rates as the natural history3. At this point it seems that the current single-level approval status and the slow acceptance of lumbar disc replacement by the commercial insurance payers have been the main impediments to the expanded utilization of these devices, not lack of successful outcomes.
Our patients are expecting to be more physically active at greater ages than in prior generations. Motion-preservation devices will allow spine surgeons to improve patients while taking into consideration the long-term health of the spine, reducing rates of future surgery caused by adjacent-segment failure. In addition to taking into consideration our patients' long-term spinal health, we have some responsibility for the cost-effectiveness and durability of the procedures that we utilize. There is significant evidence that artificial disc replacement is more cost-effective than fusion4.
References
1 Lanman TH, Burkus JK, Dryer RG, et al. Long-term clinical and radiographic outcomes of the Prestige LP artificial cervical disc replacement at 2 levels: results from a prospective randomized controlled clinical trial. Journal of neurosurgery 2017;27:7-19.
2 Zigler JE, Blumenthal SL, Guyer RD, et al. Progression of Adjacent-level Degeneration After Lumbar Total Disc Replacement: Results of a Post-hoc Analysis of Patients With Available Radiographs From a Prospective Study With 5-year Follow-up. Spine (Phila Pa 1976) 2018;43:1395-400.
3 Furunes H, Hellum C, Espeland A, et al. Adjacent Disc Degeneration After Lumbar Total Disc Replacement or Nonoperative Treatment: A Randomized Study with 8-year Follow-up. Spine (Phila Pa 1976) 2018;43:1695-703.
4 Ament JD, Yang Z, Nunley P, et al. Cost Utility Analysis of the Cervical Artificial Disc vs Fusion for the Treatment of 2-Level Symptomatic Degenerative Disc Disease: 5-Year Follow-up. Neurosurgery 2016;79:135-45.