SPINE Volume 33, Number 16, pp 1789–1792
©2008, Lippincott Williams & Wilkins
The Effect of Obesity on Clinical Outcomes After
Mladen Djurasovic, MD,*† Kelly R. Bratcher, RN,* Steven D. Glassman, MD,*†
John R. Dimar, MD,*† and Leah Y. Carreon, MD, MSc*
Study Design. Retrospective cohort analysis.
Objective. To investigate and compare back and leg
pain, and health-related quality of life measures in obese
patients undergoing lumbar spine fusion, and to compare
the results to nonobese patients.
Summary of Background Data. Obesity is a growing
healthcare crisis in the United States and an increasing
number of patients undergoing spinal surgery are obese.
Obesity is also associated with low back pain. Some obese
patients with significant structural spine problems may be
dismissed as having their pain only coming from their
weight. We compared patient outcomes in obese and nono-
bese patients undergoing lumbar fusion surgery.
Methods. We retrospectively reviewed a single-center
patient database of patients undergoing lumbar fusion
and identified 270 patients with greater than 2-year out-
come data. Body mass index (BMI) was calculated and
patients were classified as obese (BMI ? 30) or nonobese
(BMI ? 30). All patients completed Oswestry Disability
Index (ODI), Short Form (SF)-36 questionnaires, and back
and leg pain numerical rating scores before surgery and
at 2 years. We compared clinical outcomes and compli-
cation rates in the 2 groups.
Results. The overall study group consisted of 109
obese patients and 161 nonobese patients. Both the
obese and nonobese patients demonstrated significant
improvements in back pain, leg pain, SF-36 physical com-
posite summary (PCS), and ODI scores (P ? 0.001) at
2-year follow-up compared with baseline. There was no
significant difference in the mean improvements seen in
obese patients compared with nonobese patients with
respect to back pain, leg pain, or SF-36 PCS or ODI scores.
Both SF-36 PCS (P ? 0.037) and ODI score (P ? 0.028) at
2-year follow-up were better in the nonobese patients
compared with the obese patients. Overall complication
rates were slightly higher in the obese group (P ?
0.045), predominantly because of wound-related com-
Conclusion. Obese patients undergoing lumbar fusion
achieve similar benefits to nonobese patients. Wound-
related complications are more common in obese
patients. Obese patients with otherwise good indications
for lumbar fusion should not be denied this procedure
because of their weight.
Key words: obesity, lumbar spinal fusion, outcomes,
complications. Spine 2008;33:1789–1792
Obesity has reached epidemic proportions in the United
States. Current Centers for Disease Control statistics
show that 67% of the US population is now overweight
and 32% is obese.1These proportions continue to rise.
Obesity has long been associated with a multitude of
health problems, and has been shown to be an indepen-
dent risk factor for low back pain.2Recent studies exam-
ining whether obesity compromises the clinical results of
common orthopedic procedures have shown varying ef-
fects, but have generally shown an increased rate of peri-
There likely exists some degree of surgeon bias among
spinal surgeons against operating on obese patients. Sur-
geons generally perceive that operative times are longer,
exposure of the spine is more challenging and other tech-
nical aspects of the surgery more difficult. In addition, as
obesity has been associated with low back pain, it may
introduce further uncertainty regarding the source of a
particular patient’s symptoms, even in the face of other-
wise acceptable surgical indications. For this reason,
some surgeons may expect inferior clinical results in
obese patients undergoing spinal surgery.
There has been a paucity of studies examining the
effect of obesity on the clinical results of spinal sur-
gery.5,6Existing studies have looked at a mixed group of
health-related quality of life measures. Lumbar fusion is
surgeons, with more than 250,000 procedures per-
formed annually. The purpose of the current study was
to examine the effects of obesity on the clinical results
and complication rates of patients undergoing lumbar
sures and numerical rating scale of back and leg pain of
obese patients to nonobese patients.
Materials and Methods
Adult patients at a single tertiary care spine center, undergoing
lumbar fusion for degenerative conditions, were prospectively
enrolled in a surgical database from January 2001 to January
a minimum of 2-year follow-up and complete outcomes data,
and this group comprised the subjects for the current study.
From the *Kenton D. Leatherman Spine Center, and the †Department
of Orthopaedic Surgery, University of Louisville School of Medicine,
Acknowledgment date: November 13, 2007. Acceptance date: Febru-
ary 18, 2008.
The manuscript submitted does not contain information about medical
Institutional funds were received in support of this work. Although one
or more of the author(s) has/have received or will receive benefits for
personal or professional use from a commercial party related directly
or indirectly to the subject of this manuscript, benefits will be directed
solely to a research fund, foundation, educational institution, or other
nonprofit organization which the author(s) has/have been associated.
Address correspondence and reprint requests to Leah Y. Carreon, MD,
MSc, Kenton D. Leatherman Spine Center, 210 East Gray Street, Suite
900, Louisville, KY 40202; E-mail: firstname.lastname@example.org