Have you ever heard someone say they have to lose 50 or 100 pounds before the surgeon will perform a particular operation? But if you have ever watched the popular TV show Biggest Loser, then you know how much work it can be to shed those pounds.

Obesity isn't just a lifestyle choice (though that is a big part). Fat storage and metabolism (breakdown) are highly complex body functions. Fat itself has recently been identified as an active endocrine (hormonal) substance. Survival mechanisms in the body make it much easier to store fat than to shed it.

Obesity is defined as a body mass index (BMI) of 30 or more. Keep in mind that obesity comes with a whole host of other problems that complicate surgery. Patients with a BMI of 30 or more are more likely to have problems with the anesthesia.

It will be more difficult to access veins for intravenous procedures. Positioning the obese patient, changing positions, and getting him or her up and moving after surgery to avoid blood clots are important tasks but can be very difficult.

According to the results of this study, putting off surgery may not be necessary with the newer minimally invasive spinal fusion procedures. Fifteen (15) patients with a BMI greater than 30 had the less invasive posterior lumbar interbody fusion (LI-PLIF). All of these individuals had tried a more conservative approach with rehab and exercise but failed to get improvement with their painful symptoms.

The LI-PLIF procedure is done from the back of the spine (posterior approach). The surgeon uses surgical tools that can be inserted into the spine without making a large incision. Minimally invasive procedures make it possible to spare the muscles and ligaments from being cut into, which is what happens during the more invasive open incision technique.

The surgeon removes the spinal (facet) joints on either side of the affected segment. This does two things: 1) turns off pain signals coming from the joint and 2) provides the surgeon (and patient) with bone for the fusion site. It's a win-win situation for the patient.

The diseased disc is also removed. In its place, the surgeon inserts two metal mesh-like cages. Inside the cages are bone chips and bone dust from grinding up the bone removed from the joints. Additional bone will grow around the cage providing the strength and support of a pillar at that level.

By testing patients before and at regular intervals after the fusion procedure, the researchers were able to see changes in symptoms and progress in function. Other information collected and compared included length of time in surgery, amount of blood lost during the procedure, and number of days in the hospital.

Complications during (intraoperative) and after (postoperative) surgery were recorded for each patient. Less than 15 per cent had intraoperative complications. Only one-third of the group had any postoperative problems (e.g., poor wound healing, infection, continued pain). Most of those complications affected patients who were the most overweight (referred to as morbidly obese.

The main measure of interest was how many patients could return-to-work at their former job and previous (presurgical) level of function (or better). In other words, does obesity affect work outcomes after spinal fusion?

The results were very positive. With the less invasive posterior lumbar interbody fusion (LI-PLIF) procedure, there was less blood loss and therefore a shorter hospital stay. The less invasive technique was also credited with no blood transfusions, less pain, and faster return to full function. There were no blood clots or deaths among the 15 patients in this study.

The authors conclude that obesity (even morbid or extreme obesity) does not have to be an automatic "lose weight or no surgery" situation. Obese patients with chronic, unresponsive low back pain from degenerative disc disease can benefit from lumbar fusion.

The availability of newer, less invasive methods even makes it possible to get back to work within a year's time of the surgery. One final note: none of the patients who were workers compensation patients returned to work. Further study is needed to select patients for this procedure who are not at risk for poor outcomes.

Reference: Anjani K. Singh, MRCS, et al. Less Invasive Posterior Lumbar Interbody Fusion and Obesity. In The Spine Journal. November 15, 2010. Vol. 35.No. 24. Pp.2116-2120.