Study: MIS lateral spine fusion safe and effective for morbidly obese patients

Surgeons found the technique produced minimal complications in this patient population.

There are good reasons to avoid spine surgery in obese patients: traditional surgical techniques are challenging and the complication risk is significant. As a result, many surgeons do not operate on this patient population.

Surgeons in Missouri found that a minimally invasive surgery (MIS) technique addresses both problems. In their study, extreme lateral interbody fusion (XLIF, Nuvasive) offered morbidly obese patients minimal complications and good outcomes.

“It is our opinion, based on a large number of procedures in large patients, that the MIS techniques offer spinal surgeons a reproducible method to address degenerative pathologies in the morbidly obese,” said lead investigator William B. Rodgers, MD, of Jefferson City, Mo. “In our experience, this group of challenging patients was at no higher risk of complications and had roughly equivalent outcomes to those of normal body habitus.”

Re-evaluate prejudices

Rodgers told ORTHOSuperSite.com: “[These results] tell us that we as surgeons have to re-evaluate our own prejudices about whom we can and can’t help. … We have to be willing to reassess what we have taken as established dogma.

“I think that the advent of minimally invasive procedures offers us a chance to help those who have been marginalized by health care: the very old, the very heavy, and the very ill, and to allow perhaps not perfect relief of pain, but certainly a decrease in suffering by these revolutionary techniques,” he added.

Rodgers and his colleagues evaluated XLIF in a single-surgeon, prospective, nonrandomized clinical and radiographic study that included 500 patients.

The series included 81 morbidly obese patients, defined as a body mass index (BMI) greater than 38. The average BMI was 43 and the average weight was 273 lbs. Patients had the standard degenerative pathologies associated with morbid obesity, including spinal stenosis, spondylolisthesis and degenerative disc disease.

Investigators followed patients with serial exams and radiographs at 2 and 6 weeks as well as at 3, 6 and 12 months.

Similar results

Among the morbidly obese patients, average length of hospital stay was 1.38 days. Average hemoglobin change was 1.1 g. Visual Analog Scale scores dropped from 8.7 preoperatively to 2.8 for those patients who reached 1-year follow-up, Rodgers said. These results were similar to non-obese patients.

There were 7 complications, including one unilateral rod fracture, which required revision to a bilateral construct, Rodgers said. There were no infections.

Surgical procedure and instrumentation remain unchanged. “Beyond the normal surgical attention to detail, there is notthing different about it. It is just the willingness to explore through small holes into deep areas,” he said.

Gastric bypass first?

Some surgeons think obese patients should undergo gastric bypass before spine surgery. That is not necessarily the best option, Rodgers said. Gastric bypass creates major changes in the body’s homeostasis. It changes the absorptive patterns of the gut and the electrolyte milieu.

“And it changes the osteogenic and osteoclastic cascades in the bones,” he said. “There are many reasons that you might want to fix a problem that involves the bones before you did a procedure that was going to result in electrolyte imbalances.”

Rodgers and colleagues are tracking their patients’ BMI changes after surgery. “My belief is that by offering patients some improvement in quality of life, we will see at least in certain groups, a decrease in weight. You can’t exercise if you can’t walk.”

For more information:
William B. Rodgers, MD, can be reached at Spine Midwest Inc., 200 St Mary's Medical Plaza, Ste. 301, Jefferson City, MO 65101; 573-634-4212. He receives remuneration from Nuvasive for stock ownership, speaking arrangements, travel, royalties, consulting and research support for staff and materials. He receives remuneration from ExacTech for speaking arrangements and consulting.

Reference:
Rodgers WB, Cox CS, Gerber EJ. Extreme lateral interbody fusion (XLIF) in the morbidly obese. Paper #20. Presented during the North American Spine Society 23rd Annual Meeting. Oct. 14-18, 2008. Toronto.