of BMP-2 was increased 1.42, 0.73, and 3.73 times, mRNA expression of

BMP-7 was increased 2.90, 1.73, and 3.45 times respectively for each

group.

CONCLUSIONS: Both TGF-b1 and rhBMP-2 separately, can increase

proteoglycan production. However, if used in combination, they have a syn-

ergistic effect. Similarly, mRNA expression of both aggrecan and type II

collagen was increased more when TGF-b1 and rhBMP-2 were combined.

These same effects were not seen with type I collagen. BMP-2 and BMP-7

were also increased after combined treatment of TGF-b1 and rhBMP-2.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2006.06.093

Thursday, September 28, 200610:46–11:29 AM

Concurrent Session 2: Lumbar Spine-Surgical

10:46

71. Percutaneous versus Open Transforaminal Lumbar Interbody

Fusion: Safety and Outcome

Alan Villavicencio, MD1, Sigita Burneikiene, MD1, Cassandra Roeca, AS2,

Justin McLean, BA3, Jeffrey Thramann, MD1; 1Boulder Neurosurgical

Associates, Boulder, CO, USA; 2University of Colorado at Boulder,

Boulder, CO, USA; 3Boulder Community Hospital, Boulder, CO, USA

BACKGROUND CONTEXT: An open or percutaneous TLIF approach

can be utilized to treat lumbar degenerative disc disease. The percutaneous

TLIF approach is gaining popularity because of its theoretical lower tissue

morbidity rate, shorter hospitalization time, and lower blood loss. How-

ever, data supporting improved clinical outcome is lacking.

PURPOSE: The purpose of this study was to directly compare safety, fea-

sibility, and outcomes for these two different approaches.

STUDY DESIGN/SETTING: TLIF surgical cases performed between

September 2002 and December 2004 at Boulder Community and Long-

mont United Hospitals (Boulder, CO) were retrospectively analyzed.

PATIENT SAMPLE: 180 consecutive patients treated for degenerative

disc disease with or without disc herniation, spondylolisthesis and/or ste-

nosis were included into this study.

OUTCOME MEASURES: Operative data, length of hospitalization, clin-

ical outcome (MacNab’s Criteria, Patient Satisfaction with Results Survey)

and reoperation rate were used to compare these two different approaches.

Complication assessment was performed using clinical and radiographical

examinations to analyze the safety of either approach for an average of 24

months after surgery.

METHODS: Patients were allocated to the open (n5104) or percutaneous

(n576) TLIF group depending on the number of surgically treated spinal

levels, whether the patient had previously undergone lumbar surgery and

the presence of bilateral disease, or spondylolisthesis. Demographic data

were similar in both patient groups, except for the number of previous sur-

geries and two-level procedures performed (p5.001). Complications were

classified as either major or minor. Patients were followed for an average

of 24 months (range 12–39 months).

RESULTS: Mean operative time was 206.7 min (range 108-517 min) for

open and 221.4 min (range 114–370 min) for percutaneous procedures

(p5.2). Mean operative blood loss was 327.1 mL (range 25–2500 mL)

for open and 163.9 mL (range 25–750 mL) for percutaneous procedures

(p5.0001). Mean hospitalization time was 5.5 days (range 1–24 days)

for open and 3.0 days (range 1–16 days) for percutaneous procedures

(p5.0017). Clinical outcome defined as patients’ perceived overall treat-

ment effect (MacNab Criteria) was excellent/good in 67% of open ap-

proach cases and 66% of percutaneously performed cases. Overall

patient satisfaction rate was 69.5% in open and 64.3% in percutaneous

TLIF cases (p5.7). Additional surgical procedures were performed for a to-

tal of 11.1% and 6.6% patients in the open and percutaneous TLIF groups

respectively at an average of 14 months. The total complication rates were

similar for both percutaneous and open approaches (27.6% and 28.4%, re-

spectively). The major complication rate was higher in the percutaneously

performed TLIF procedures: 15.8% and 9.9%, respectively, but it was not

statistically significant (p5.1).

CONCLUSIONS: Although percutaneous TLIF approaches have theoret-

ical advantages over open TLIF approaches, this study implies that both

open and percutaneous surgical techniques are feasible and can be safely

performed to treat lumbar degenerative disc disease. The percutaneous ap-

proach is associated with reduced blood loss and length of hospitalization

in comparison to the open approach and does not increase operative time.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2006.06.095

10:52

72. Herniated Disc Morphology and Outcome of Selective Nerve

Root Block in Acute Sciatica

Paul Bishop, DC, MD, PhD1, Peter Wing, MB, MSc, FRCS (C)2,

Michael Boyd, MD, FRCS (C)3, Charles Fisher, MD, MHSc, FRCS (C)4,

Marcel Dvorak, MD, FRCS (C)5; 1Vancouver Gen. Hospital, Vancouver,

British Columbia, Canada; 2Combined Spine Program Vancouver Gen.

Hospital, Vancouver, British Columbia, Canada; 3Vancouver Hospital,

Vancouver, British Columbia, Canada; 4Vancouver Hospital, Vancouver,

British Columbia, Canada; 5University of British Columbia, Vancouver,

British Columbia, Canada

BACKGROUND CONTEXT: The clinical sequelae associated with acute

sciatica have been traditionally attributed to mechanical compression of

the spinal nerve root by a herniated disc (HD). More recent studies have

demonstrated that the HD induces the release of inflammatory mediators

and that a tumor necrosis factor alpha-inhibiting agent can resolve the

symptoms. Selective nerve root block (SNRB) involves the transforaminal

application of steroid under fluoroscopic guidance adjacent to the selected

nerve root. Well-defined criteria for patients who will most likely benefit

from SNRB remain unclear.

PURPOSE: The goal of this study was to determine whether or not the

morphology (ie posterolateral, sequestrated, foraminal, far lateral) of HD

influences the therapeutic value of SNRB treatment.

STUDY DESIGN/SETTING: An observational cohort study.

PATIENT SAMPLE: 37 patients with acute sciatica of less than 12 weeks

duration, McCulloch scores of 4 or 5, and evidence of HD on MRI scan at

the appropriate level were included.

OUTCOME MEASURES: Outcome measures included the Modified Ro-

land-Morris Disability Questionnaire (RDQ) and the Visual Analogue

Scale (VAS).

METHODS: Disc morphology was determined by blinded interpretation

of the MRI scans by a Musculoskeletal Radiologist. The RDQ was admin-

istered on the day of, and 6 weeks following, the SNRB procedure. The

VAS was filled out by the patient immediately before, 30 minutes after,

and 6 weeks after SNRB

RESULTS: Of the 37 patients enrolled in this study, the HD morphology

was classified as: posterolateral 20, sequestrated 9, foraminal 6, far lateral

2. 35 of 37 patients (95%) reported a 30 minute VAS score of less than 3/

10. 14 of 20 patients (70%) with posterolateral HD reported O3 point im-

provement in RDQ and O5 point improvement in VAS at 6 weeks postpro-

cedure. 1 of 9 patients (11%) with sequestrated HD showed the same level

of improvement in RDQ and VAS scores. None of the patients with foram-

inal or far lateral HD reported O1 point improvement in RDQ or O2 point

improvement in VAS scores.

36S Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S

CONCLUSIONS: Patients with posterolateral HD were found to have

significantly more favorable outcomes from SNRB than those with

sequestrated, foraminal, or far lateral HD morphology.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2006.06.096

10:58

73. Intraoperative Cell Saver Does Not Decrease Postoperative Blood

Transfusion in Instrumented Lumbar Fusion Patients

Paul Gause, MD, Peter Siska, MD, Edward Westrick, BS, James Irrgang,

PhD, James Kang, MD; University of Pittsburgh, Pittsburgh, PA, USA

BACKGROUND CONTEXT: The use of blood products in the treatment

of postoperative anemia continues to pose risks of allergic reactions,

hemolytic reactions, isoimmunization, graft versus host reactions,

increased infection rates, and transmission of blood-borne pathogens. Al-

though our previous study has shown that autologous blood donations

can help limit and decrease the chances of requiring additional allogeneic

blood, it still did not completely eliminate the risk of further allogeneic

blood transfusions. Because posterior lumbar fusion surgery can be associ-

ated with major intraoperative blood loss, the use of intraoperative cell

saver (CS) has been advocated as a means of further decreasing the post-

operative allogeneic transfusion requirements in these lumbar fusion pa-

tients. However, some studies have questioned the effectiveness of cell

saver in elective lumbar fusion surgery, and furthermore, it is unknown

if it can actually decrease allogeneic blood usage in patients who also pre-

donated autologous blood.

PURPOSE: The purpose of this study was to determine whether there was

a significant decrease in the number of allogeneic postoperative blood

transfusions when intraoperative CS was used.

STUDY DESIGN/SETTING: The hospital charts and operating room

records of 240 instrumented lumbar fusion patients were retrospectively

reviewed. Patients underwent the operative procedure and were admitted

at the senior author’s institution.

PATIENT SAMPLE: The subject population included all patients under-

going elective instrumented posterior lumbar spinal fusions. The patients

ranged in age from 36 to 85. All patients were treated by the senior author.

OUTCOME MEASURES: The primary outcome measures were the

number of PRBC transfused in the postoperative period and hematocrit

at discharge.

METHODS: The patients underwent posterior lumbar fusion using a stan-

dard posterior approach, segmental pedicle screw fixation, and postero-lat-

eral decortication with bone grafting. Intraoperative CS was used in 141

patients compared with 99 control patients. Data collected included esti-

mated blood loss, cell saver re-infused, pre- and postoperative hemoglobin

and hematocrit, and units of packed red blood cells (PRBC) transfused.

RESULTS: Postoperative transfusion requirements were higher in the CS

group versus the non-CS group, however this difference was not statisti-

cally significant (2.7 vs. 2.3, p 5 .091). There was no statistical difference

for discharge hematocrit between the CS and non-CS groups (28.7 vs. 28,

p5.06) (Fig. 1).

CONCLUSIONS: In this series of 240 instrumented posterior lumbar fu-

sion patients, use of intraoperative cell saver did not decrease the number

of postoperative allogeneic blood transfusions, and did not result in an in-

creased hematocrit at discharge. These results suggest that the use of intra-

operative cell saver may not be beneficial for use in elective instrumented

posterior lumbar spinal fusion surgery as an adjunct to preoperative

autologous blood donation.

FDA DEVICE/DRUG STATUS: Cell Saver: Approved for this indication.

CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2006.06.097

11:04

74. Risk Factors for Surgical Site Infection Following Spinal Surgery

David Cohen, MD, MPH, Trish Perl, MD, MSc, Lee Riley, III, MD,

Xiaoyan Song, MD, Lisa Maragakis, MD; Johns Hopkins University,

Baltimore, MD, USA

BACKGROUND CONTEXT: Surgical site infection (SSI) after spinal

surgery results in increased morbidity, mortality, length of hospital stay,

and health-care costs. Most previously identified risk factors for SSI after

spinal surgery are not amenable to interventions to decrease rates.

PURPOSE: We sought to identify modifiable risk factors for SSI after

laminectomy or spinal fusion that might be used to design interventions

to decrease infection rates.

STUDY DESIGN/SETTING: This is a case-control study with group

matching of SSIs after spinal surgery performed at a university teaching

hospital over a 42-month period.

PATIENT SAMPLE: 104 cases of SSI were group matched to 104 con-

trols from among 3,894 laminectomy or fusion procedures performed dur-

ing the study period.

OUTCOME MEASURES: Odd ratios with 95% confidence intervals

were determined using multivariate analysis.

METHODS: ICD-9 codes from adminstrative databases were used to

identify all patients who underwent laminectomy or spinal fusion at our in-

stitution between April 1, 2001 and December 31, 2004. Inpatient and out-

patient medical records of all patients who underwent these procedures

were reviewed to identify cases of SSI. SSI was defined according to Cen-

ters for Disease Control and Prevention (CDC) criteria. A case-control in-

vestigation compared cases of SSI after spinal laminectomy or fusion to

control patients randomly selected from a list of patients without SSI

who underwent spinal surgery in the study period. One control was se-

lected for each case, and group matching was employed to ensure an equal

proportions of cases and controls in each year of the study. The complete

medical records for all cases and controls were abstracted for both known

and potential SSI risk factors.

RESULTS: During the study period, 3,894 laminectomy or spinal fusion

procedures were performed at our institution. One hundred and four

patients developed a SSI, for an overall rate of 2.67 per 100 procedures.

Multivariate analysis identified several independant risk factors for SSI in-

cluding prolonged duration of procedure (odds ratio [OR] 3.0, 95% confi-

dence interval [CI] 1.1-7.9, p5.03), American Society of Anesthesiologist

(ASA) score of 3 or greater (OR 9.1, 95% CI 3–28, p5.001), lumbar-sacral

operative level (OR 3.0, 95% CI 1.1-8.6, p5.04), and obesity (OR 5.0,

95% CI 1.9–13.1, p5.001). Having no hair removal before surgery was

protective (OR 0.21, 95% CI 0.07-0.60, p5.003) as was having an intrao-

perative fraction of inspired oxygen (FiO2) of at least 50% (OR 0.08, 95%

CI 0.03-0.24, p!.001).

CONCLUSIONS: Prolonged duration of surgery, ASA score, obesity, and

lumbar-sacral surgical level were independent risk factors for SSI after

laminectomy or spinal fusion in this study population. Avoiding hair re-

moval and administering at least 50% FiO2 were highly protective againstFig. 1. Transfusion requirements and EBL.

37SProceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S