MIS for the Spine Improves Deformity with Fewer Intraoperative Complications and Lower Costs

31st Annual Meeting of the North American Spine Society Highlight

Minimally invasive surgery (MIS) for the spine improves deformity and is associated with fewer intraoperative complications and lower costs according to a presentation given by Dr. Khoi Than during the 2016 Annual Meeting of the North American Spine Society.

Khoi Than, MD is an Assistant Professor in the Department of Neurological Surgery at Oregon Health & Science University in Portland and gave a talk on MIS deformity surgery. “A pure MIS technique can improve the coronal Cobb angle a maximum of 40 degrees, the sagittal vertical axis (SVA) a maximum of 9 cm and is associated with fewer intraoperative complications and DVT’s.”
X-ray image of scoliosis in the thoracic spineX-ray image of scoliosis in the thoracic spine. Image Courtesy of SpineUniverse.com.

Deformity Correction

The first paper Dr. Than discussed on deformity correction was by N. Anand et al (Neurosurg Focus. 2014 May;36(5):E14). “This was a paper out of Cedars-Sinai looking at ceiling effects using circumferential MIS (cMIS) techniques over a period of 7 years,” Dr. Than said. The study included 90 patients who were selected from a database of 187 patients that had Cobb angles greater than 15 degrees and 3 or more levels fused. “What the authors found was an average correction in the SVA of 3 cm, with a maximum of 9 cm. The average coronal Cobb angle correction was 22 degrees with a maximum of 42 degrees, and the average increase in lumbar lordosis was 4 degrees with a maximum of 29 degrees.”

The second study Dr. Than discussed was by MY Wang et al (Neurosurg Focus. 2014 May;36(5):E12), which compared three MIS techniques for deformity. These included stand-alone laterals, cMIS techniques, and hybrid techniques. “The authors found that the average Cobb angle correction was about 6 degrees with stand-alone laterals and up to a maximum of 23 degrees. Those who had the cMIS techniques averaged a 20 degree Cobb angle correction up to a maximum of 35 degrees, and those who had a hybrid technique averaged a 28 degree coronal Cobb correction up to a maximum of 55 degrees.”

The third study discussed compared two MIS techniques; the hybrid approach involving lateral interbody fusion with open posterior instrumented fusion, and cMIS (P. Park et al. J Neurosurg Spine. 2015 Apr;22(4):374-80). “Interestingly, there is a substantially higher rate of complications in hybrid patients; about 55% compared to 33% in the cMIS patients,” Dr. Than commented.

More on Complication Rates

In a study by Uribe et al (Neurosurg Focus. 2014 May;36(5):E15), the researchers compared complications in minimally invasive, hybrid and open surgical techniques with 20 well-matched patients in each group. Dr. Than commented, “Overall, the complication rate was 45%. I think this is a valuable number to counsel patients undergoing deformity surgery preoperatively. The MIS group had a lower estimated blood loss, but there was no difference between the other groups regarding total complications, postoperative complications or major complications. Also, there was a much lower rate of intraoperative complications in the cMIS group compared to the hybrid and especially compared to the open group. An important conclusion is that all the groups had substantial improvements in their VAS back pain and their Oswestry Disability Index.”


Dr. Than discussed a study by DK Hamilton et al (Eur Spine J. 2016 Aug;25(8):2605-11), which evaluated reoperation rates in minimally invasive, hybrid and open surgical treatment of adult spinal deformity. “This study showed, kind of surprisingly, that the hybrid patients had the highest rates of reoperation, while the lowest rate was in the cMIS patients.”

Predictors for Good Outcomes

In a study wherein he was the lead author (J Neurosurg Spine. 2016 Jul;25(1):21-5) the clinical and radiographic parameters associated with best versus worst clinical outcomes were evaluated, and Dr. Than explained the findings. “One of the keys in this study was in the postoperative findings. The group with the best outcomes had a relative matching of their pelvic incidence (PI) to lumbar lordosis (LL) and had a normal SVA, and the worst group did not.”

Dr. Than stressed that whether doing open deformity or MIS deformity surgery, the focus must be on correcting the patient’s SVA and PI to LL mismatch.

Cost Comparisons

Next was a review of the study by OM Uddin et al (J Neurosurg Spine. 2015 Dec;23(6):798-806), which evaluated cost comparisons between MIS and open surgery for adult degenerative scoliosis.

“This group out of Northwestern found a substantially lower cost regarding inpatient charges in the MIS group. The length of stay in the open group was nearly 2 weeks, which I found a little surprising. However, despite the higher costs and the longer hospital stay, the open group did have a more substantial improvement in their visual analog scale as well as in deformity correction,” Dr. Than concluded.

To view additional meeting highlights from the 31st Annual Meeting of NASS, click here.

Updated on: 05/26/19
Continue Reading
Patient Satisfaction Following Spine Surgery is Not Associated with Greater Opioid Use

Get new patient cases delivered to your inbox

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