Does Minimally Invasive Lumbar Fusion Benefit Patients Compared With Open Surgery?

Praveen Mummaneni, MD, provides insightful comments.

Peer Reviewed

Minimally invasive lumbar fusion is linked to less blood loss compared with open surgery—but only a modest reduction in hospital length of stay, and no difference in return to work, 90-day safety profile, and patient-reported outcomes. The findings were described as “surprising” to co-author Praveen Mummaneni, MD, Professor and Vice-Chairman of the Department of Neurosurgery and Co-director of the Spine Center at the University of California San Francisco Medical Center.

“The findings can help with the nuance of selecting indications that are best treated minimally invasively versus with open surgery,” Dr. Mummaneni said. He believes that both approaches have benefited from technological innovation, which explains why many outcomes assessed in the study were not significantly different between the surgical groups.

For example, “Surgeons have become more sophisticated in their length of stay management and are still getting patients out of the hospital fairly quickly even with open surgery,” Dr. Mummaneni told SpineUniverse. While in the past, open surgery required a 5- to 6-day hospital stay, this analysis shows that patients were discharged in under 4 days, he explained.
female nurse helping patient to walk using walker in hospitalThe researchers identified 2,036 patients who underwent one- and two-level lumbar interbody fusion for lumbar stenosis or Grade 1 spondylolisthesis and had 12-month follow-up data available. Photo Source:

Data Collected From an Observational, Prospective National Registry

The observational analysis included prospectively collected data from the 2010-2014 National Neurosurgery Quality and Outcomes Database (N2QOD). The researchers identified 2,036 patients who underwent one- and two-level lumbar interbody fusion for lumbar stenosis or Grade 1 spondylolisthesis and had 12-month follow-up data available.

Nearly one-quarter of these patients (n=467; 24%) underwent minimally invasive surgery (MIS) and three-fourths underwent open surgery (n=1480; 76%). The MIS group was significantly younger, had lower disability scores, were rated as healthier on the American Society of Anesthesiologists' grade, and were more likely to have private insurance, diabetes, and one-level vs two-level fusions (P>0.05 for all comparisons).

After matching for demographic and perioperative surgical characteristics (Table), only estimated blood loss was significantly improved between the MIS and open surgery groups for one- and two-level fusions (P<0.001 and =0.002, respectively). Length of stay was slightly less in the MIS group for one-level fusions (P=0.049), but was not significantly different compared with the open surgery group for either one- or two-level fusions.
Table. Propensity-matched Comparison of MIS Versus Open Surgical Approach to Lumbar FusionThe following outcomes were not significantly different between the two groups:

  • Length of surgery
  • Discharge status
  • Readmission to the hospital within 90 days
  • Revision surgery within 30-days
  • 30-day morbidities
  • Return to work within 12 months of surgery
  • Patient reported outcomes

When Is Open Surgery Preferred?

Dr. Mummaneni noted that for some patients, open surgery may be preferable. For example, he noted that for “a patient who has a degenerative spondylolisthesis, severe bilateral stenosis, a facet joint cyst, you could perform MIS but open surgery will take less time because all the anatomy is exposed and allows for easy removal of abnormalities.”

The question that surgeons ask themselves is, "Is it worth it for me to do it minimally invasively and spend extra operative time, or can I do the case much better and faster using open surgery?," Dr. Mummaneni said. “In this case, I would consider that I am probably going to lose a little less blood if I use a minimally invasive approach, but it is not going to make a dramatic difference in the patient’s length of stay, need for inpatient rehabilitation, or return to work. Thus, because of the technical difficulties of the case, I might decide to use an open approach.”

When Is Minimally Invasive Surgery Preferred?

“On the other hand, if I saw a patient with less severe stenosis and slippage who requires decompression on one side, I would probably choose the minimally invasive rather than open approach, because the surgery can be performed fairly quickly with either approach, but the patient will lose less blood with the MIS approach,” Dr. Mummaneni explained.

In the era of value-based medicine, Dr. Mummaneni said it is important to consider whether the benefits of MIS outweigh the potentially increased costs. In fact, he and his colleagues are using data from the N2QOD to compare quality-adjusted life years of one-level spondylolisthesis performed using MIS versus open surgery. The researchers currently have 1 year of follow-up data available, and are waiting for 2-year follow-up data to analyze the results.

Updated on: 06/06/19
Continue Reading
Laminectomy Plus Fusion and Laminoplasty Show Equivalent Efficacy in the Treatment of Degenerative Cervical Myelopathy
Praveen V. Mummaneni, MD
Department of Neurosurgery
University of California San Francisco
San Francisco, CA

Get new patient cases delivered to your inbox

Sign up for our healthcare professional eNewsletter, SpineMonitor.
Sign Up!