At the North American Spine Society 28th Annual Meeting earlier this month, several spine surgeons gathered to discuss the current controversies with minimally invasive lumbar fusion and whether to adopt it for their practices.
The panel was moderated by Y. Raja Rampersaud, MD, FRCSC, and included perspectives from surgeons that have adopted MIS, surgeons who are not a proponent of adopting current MIS techniques and surgeons reviewing the literature.
Argument against MIS
Alexander R. Vaccaro, MD, PhD, gave the first presentation discussing why he has not adopted MIS lumbar fusion into his practice.
He also mentioned as arguments against MIS:
• Questions about outcomes comparison
• Radiation exposure
• Complication rates
• Technology for screw placement
• Cost
"We spend too much time learning, [there is] radiation exposure and most importantly the outcome has not been proven to me that it's worth the effort at this time and so until the technology changes, I'm not a big advocate of MIS surgery," Dr. Vaccaro said.
Argument for MIS
Kevin T. Foley, MD, FASC, then spoke on why MIS lumbar fusion is routine in his practice. "I do almost everything MIS. I still do a number of open cases but on a routine basis handle things in the least invasive way I can," Dr. Foley said. "The rationale for any minimally invasive surgery is to try to reduce approach-related morbidity, but at the same time you have to maintain efficacy. So if you aren't maintaining efficacy, what you are doing to reduce morbidity isn't worth it."
Dr. Foley argued that less invasive procedures are often reported as less painful for patients and when performed by a competent surgeon could achieve at least similar outcomes. He cited research results showing minimally invasive versus open transforaminal lumbar interbody fusion that showed:
• More adverse events in the open group
• Less blood loss in the MIS group
• Overall clinical results were comparable
• The cost also favored the MIS group, at $14,183 on average versus $18,633 for open lumbar fusion
The study, "Cost-utility analysis of posterior minimally invasive fusion compared with conventional open fusion for lumbar spondylolisthesis," was published in SAS Journal in 2011.
"There is a lot of hype out there with minimally invasive surgery, no question, and a lot of people who are inexperienced rushing to do it and that can lead to some of the outcomes Dr. Vaccaro showed us but that doesn't mean that competent people who are doing it can't do a good job," said Dr. Foley.
The bottom line, Dr. Foley said, comes down to physician and patient preference. He advised physicians to perform surgeries that they are able to achieve good outcomes with and are comfortable with. Patients seek him out, he said, because former patients with good outcomes refer their friends and family.
"Why I use MIS surgery, in conclusion, is that I have little blood loss; I don't get patient transfusions; I never have to put a drain in and worry about playing with that; I have a low complication rate and I have no deep infections and my outcomes are routinely good. My patients are happy and they keep sending me more patients, so it keeps my practice busy," said Dr. Foley.
Clinical outcomes comparison
Charles G. Fischer, MD, MHSc, presented the comparative clinical evidence for minimally invasive and open spinal fusions. When examining the data, he recommended looking closely at inclusions and exclusions to really understand the literature. One of the holes in the literature is how recovery time for each is presented; open procedures often require a few days at the hospital compared to the minimally invasive surgeries that allow patients to return home the next day. What you tell patients is important, Dr. Fisher said.
"That has a big impact on patients but the literature doesn't really look at that carefully so that's important to keep in mind," said Dr. Fisher.
From 26 papers that were examined in an overview of the literature, only one was a prospective, randomized, controlled trial. "There isn't a lot of good literature," said Dr. Fisher. "There aren't a lot of good studies on this topic."
He went over literature examining:
• Outcomes
• Adverse events
• Blood loss
• Infection
"A take home message here from a literature perspective is that from an infection and blood loss perspective, MIS is definitely better. That is well supported in the literature. With respect to other adverse events: misplacement of hardware, dural care, it seems equivocal," said Dr. Fisher. He then offered conclusions that operative time is similar between both procedures after the learning curve is overcome.
Emerging data also follows whether patients still report similar or better outcomes from minimally invasive surgery after two years. "We don't need to worry about two-year outcomes with respect to open surgery versus MIS because they seem equivalent," said Dr. Fisher. He concluded by addressing whether fusion is achieved better with open or MIS, showing that MIS could achieve similar fusion rates.
Economic impact of open vs. MIS
Finally, Daniel K. Resnick, MD, MS, spoke about the comparative health and economics between open and MIS TLIF patients. He critiqued multiple studies which used administrative data to compare costs, which doesn't necessarily paint an accurate picture of costs.
"Despite the limitations of the current literature, the literature suggests that the two techniques work, and I would agree with that entirely. It would be very difficult to demonstrate a clinical sequela or clinically significant difference between the two in terms of cost for quality," said Dr. Resnick. He suggested instead examining cost for cost-savings.
He also examined return to work, finding a cost benefit if minimally invasive procedures are able to return people to work more quickly. When analyzing the data, he encouraged researchers to consider surgeon skill set, patient factors and setting that could influence outcomes.
"The setting makes a big difference. Costs are 40 percent less in ambulatory surgery center, which is attached to our hospital, versus the same procedure 100 yards west in our ORs which are inside the hospital," said Dr. Resnick. "One of our surgeons realized nearly 20 percent savings by switching from disposable to non-disposable instrumentation set during the same procedure."
He concluded both open and minimally invasive TLIF were cost-effective in the appropriate patient when compared with non-operative management.
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