51SProceedings of the NASS 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S

outcomes. While there is significant data on its indications and outcomes,

no study to our knowledge has examined the surgeon preferences for cer-

tain options in how to perform the procedure.

PURPOSE: To identify surgeon preferences for the type of interbody

spacer, use of neuromonitoring, and operating microscope in ALIF surger-

ies and measure changes in these preferences over time.

STUDY DESIGN/SETTING: Retrospective database review.

PATIENT SAMPLE: All patients in the PearlDiver insurance database

having ALIF surgery from 2004 to 2007.

METHODS: A retrospective review using a commercially available on-

line database of insurance billing records identified patients undergoing

single or multilevel ALIF by presence of appropriate CPT codes (22558

+/- 22585). Records were cross-referenced for CPT codes for use of struc-

tural autograft (20938), structural allograft (20930), intervertebral cage

(22851), intraoperative microscope (69990), and neurophysiologic moni-

toring (95920). Data was stratified by age in two cohorts, 15–44 and

45–64 years old. Data with all ages was also stratified based upon gender

and year of surgery.

RESULTS: A total of 3109 patients were identified (1807 female, 1302

male, 1589 younger, 1502 older). Allografts were used in 542 (17%) cases,

autograft in 97 (3%), and intervertebral cage in 2576 (80%). Spacer choice

did not change significantly over time (allograft 17% in 2004 to 17% in

2007, cages 80% to 81%, and autograft 4% to 3%). The proportional

use of each spacer type was similar between the two age groups as well

as between both genders. Both neurophysiologic monitoring and operating

microscope were used in 59 patients (2%), neither modality was used in

2398 (75%), microscope without neuromonitoring was used in 207

(6.5%), and monitoring alone was used in 514 (16.5%). The use of neuro-

physiologic monitoring rose from 13% to 19% from 2004–2007. There

was essentially no difference in the rates of monitoring or microscope

use based on age or gender. Results are summarized in Table 1.

CONCLUSIONS: Intervertebral cage is favored over allograft and auto-

graft, with no significant change in rate of use over time. Utilization of

both neuromonitoring and the operating microscope increased over time.

Both the spacer type and the use of adjunct modalities appear to be the

same regardless of age or gender, suggesting that surgeon preference is in-

dependent of these factors.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2010.07.138

110. Patients Perceive No Increased Functional Limitations Due

to Lumbar Spinal Stiffness after Posterior Instrumented Arthrodesis

of One to Three Levels

Jayme R. Hiratzka, MD, Shannon L. Hiratzka, MPH, Kara Lanning,

Robert A. Hart, MD; Oregon Health & Science University, Portland, OR,

USA

BACKGROUND CONTEXT: Increasing numbers of patients are under-

going lumbar spine fusion procedures in the United States. While these

surgeries are often successful in relieving pain due to instability, these ben-

efits necessarily come with a corresponding loss of lumbar range of mo-

tion. Many patients express concern regarding the potential functional

impact these limitations will bring. Previous studies have validated a 10

question survey (Lumbar Spine Disability Index, LSDI) and found that

limitations in ADL’s resulting from stiffness track separately from Oswes-

try Disability Index scores. To date no prospective studies have been car-

ried out to assess how patients perceive functional limitations due to

stiffness following lumbar arthrodesis.

PURPOSE: The purpose of the this study is to determine the degree to

which patients perceive limitations in ADL’s due to stiffness after lumbar

arthrodesis of 1–3 levels.

STUDY DESIGN/SETTING: Prospective cohort study.

All referenced figures and tables will be available at the Annual Mee

PATIENT SAMPLE: 46 consecutive adult patients undergoing 1–3 level

posterior instrumented lumbar fusion at a single center.

OUTCOME MEASURES: Lumbar Spine Disability Index (LSDI).

METHODS: The LSDI was prospectively administered to 46 patients un-

dergoing elective primary posterior instrumented lumbar fusion of 1- to 3-

motion segments for either degenerative disk disease or spondylolisthesis.

LSDI scoreswere collected preoperatively and at 12months postoperatively.

RESULTS: LSDI scores were analyzed using a paired t-test. Overall, there

was a statistically significant decrease in LSDI score from preoperative to

one-year postoperative for patients undergoing 1-level fusion of 11.85%

(95%CI -19.45%, -4.25%; p50.0035).No significant changes in LSDI scores

were seen for patients undergoing 2-level (3.05%, 95%CI -7.32%, 13.52%;

p50.5309)and3-level (-5.09%;95%CI -20.37%,10.19%;p50.4307) fusions.

CONCLUSIONS: At 1-year follow-up, patients undergoing posterior in-

strumented fusion of a single lumbar level actually report a decrease in dif-

ficulty with ADL’s due to lumbar stiffness when compared to preoperative

values. This result occurs despite the elimination of motion at the operated

spine segment. No difference in functional effect for patients undergoing

2-or 3-level fusion could be demonstrated with the available numbers. Fur-

ther follow-up of this patient cohort out to two years is ongoing. Based on

these one year results, however, it appears that patients do not suffer sub-

stantial increased functional limitations due to stiffness following lumbar

arthrodesis of 1 to 3 motion segments.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2010.07.139

Thursday, October 7, 20105:00–6:00 PM

Focused Paper Presentations 2: MinimallyInvasive Surgery

111. The Subsidence Rate in XLIF Osteoporotic Patients

in Standalone Procedures

Leonardo Oliveira, BSc1, Luis Marchi, MSc2, Etevaldo Coutinho, MD2,

Luiz Pimenta, MD, PhD2; 1Universidade Federal de Sao Paulo, Sao Paulo,

Brazil; 2Instituto de Patologia da Coluna, Sao Paulo, Brazil

BACKGROUND CONTEXT: Low back pain resulting from degenerative

disease of the lumbosacral spine is a major cause of morbidity, disability

and lost productivity. This treatable condition is often a major cause of in-

activity, loss of productivity and, potentially, loss of independence in many

persons, particularly older persons. For these conditions there are some

non-surgical and surgical options. Within the surgical options there is an

efficient and minimally disruptive technique, the XLIF. This is a lateral

transpsoas approach that reaches the anterior spine portion without remov-

ing spine ligaments or disrupting surrounding muscles. The XLIF cages

used for fusion reach the cortical bone bilaterally and have bigger footprint

than the ALIF or PLIF ones, giving stronger support for the vertebral body.

The standard cage is 18 mm wide (antero-posterior size) and is able to in-

direct decompress the foramen, allowing improvement in clinical and ra-

diological assessments. But we detected that in the majority of the cases

there were an important endplate remodeling and subsidence, which could

minimize better results in this technique. So, our thesis is that wider cages

(22 mm) can provide better clinical/radiological results for lumbar fusion

by XLIF.

PURPOSE: The purpose of the abstract is to present an alternative to im-

prove clinical and radiological results for lumbar fusion using the XLIF

technique in stand alone constructions.

STUDY DESIGN/SETTING: Prospective, randomized, controlled, single

center clinical study to compare the clinical and radiological results afterXLIF

stand alone procedure using standard (18 mm) and wide (22 mm) cages.

ting and will be included with the post-meeting online content.

52S Proceedings of the NASS 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S

PATIENT SAMPLE: After the randomization, 21 patients with central or

lateral stenosis underwent theXLIF StandAlone procedurewith standard ca-

ges (18 mm) at 41 lumbar levels and 22 patients with wide cages (22 mm) at

36 lumbar levels.

OUTCOME MEASURES: X-rays, MRI and clinical outcome assess-

ments using Oswestry and VAS scores were performed preoperatively, pre-

operatively at 1 and 6 weeks, 3, 6 and 12 months after surgery.

METHODS: The extreme lateral approach was done through the retroper-

itoneal space and through psoasmuscle avoiding vascular and neural lesions.

A partial discectomy was done and the end-plate cleaned preserving ALL,

keeping the spinemore stable than the traditional surgery. Radiological mea-

surements were done usingmedical imaging software at preoperatively, pre-

operatively at 1 week and 3 months. The mean age was 67.6 y/o (40 - 83) for

standard and 65 y/o (45 - 85) for wide group.

RESULTS: All patients completed 12-month follow-up evaluations. VAS

and ODI scores improved equally in both groups at the all follow-up periods

when compared to the preoperative scores. Although all patients had postop-

eratively gain in disc height and foramen measurements (56% for standard

and 65% for wide), after 3 months, standard group had lost 33.9% of its disc

heightmean, whilewide group had no significant lost. These results are com-

pleted with the found that at 3 month-follow up it was significant difference

in subsidence/endplate remodeling rate,whichwas at 9.7%forwide and 31%

for standard group.

CONCLUSIONS: Indirect decompression with XLIF is feasible and effec-

tive.With critical analysis during the surgery practice, wewere able to detect

that the standard cages caused an important rate of subsidence at the operated

levels and the technique could be improved. The thesis was correct and the

disc space restoring was achieved and sustained with 22 mm cages, which

could make the technique even more effective for lumbar fusion and indirect

decompression.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2010.07.141

112. Indirect Decompression of Lumbar Spondylolisthesis Using

Anterior Lumbar Interbody Fusion and Minimally Invasive Pedicle

Screw Fixation

Richard D. Guyer, MD1, Jessica Shellock, MD2, Michael S. Hisey, MD1,

W. Daniel Bradley, MD1, Donna D. Ohnmeiss, DrMed2; 1Texas Back

Institute, Plano, TX, USA; 2Texas Back Institute Research Foundation,

Plano, TX, USA

BACKGROUND CONTEXT: Lumbar spondylolisthesis is a common

disorder for which numerous surgical strategies exist. One technique that

has received little attention is anterior lumbar interbody fusion (ALIF)

combined with posterior instrumentation without decompression.

PURPOSE: The purpose of this study was to evaluate the clinical and ra-

diographic outcome of a group of patients with symptomatic lumbar spon-

dylolisthesis who underwent ALIF and minimally invasive pedicle screw

fixation without direct posterior decompression.

STUDY DESIGN/SETTING: This studywas based on reviewof charts and

radiographs of patients undergoing ALIF and minimally invasive screw

placement beginning with the first case experience in a group of spine spe-

cialty surgeons.

PATIENT SAMPLE: Radiographs and charts were reviewed for the con-

secutive series of 41 patients with spondylolisthesis, unresponsive to non-

operative management, who underwent ALIF and minimally invasive

screw placement beginning with the first case experience.

OUTCOME MEASURES: Outcome measures included the Oswestry

(ODI), visual analog scales (VAS) assessing back and leg pain, and radio-

graphic measure of slip and disc height of the operated segment.

METHODS: Patients undergoing the described procedure were identified

from a surgical database. Chart review and radiograph measures were per-

formed by a single surgeon not involved with the cases. An ODI and VAS

All referenced figures and tables will be available at the Annual Mee

were mailed to patients who had not been followed in the clinic recently.

Eight patients underwent adjacent segment fusion during the same opera-

tive setting due to painful disc degeneration. The mean length of clinical

follow-up was 19.2 months.

RESULTS: Mean operative time was 158.3 minutes, blood loss 80.1 cc,

and length of hospital stay 1.9 days. Back pain, leg pain, and ODI scores

all improved significantly (see Table 1). Radiographically, the amount of

slip was significantly reduced and disc space height increased. At least

85.4% of patients had a solid fusion. In the remaining patients, radiographic

follow-upofmore than 6monthswas not available due to the patient’s remote

location or pregnancy. There were no cases of pseudoarthrosis, malposi-

tioned or broken pedicle screws or rods identified. One patient underwent

re-operation for a wound infection and three patients underwent pedicle

screw removal after fusion was achieved.

CONCLUSIONS: This study found that indirect decompression using

ALIF combined with percutaneous pedicle screws resulted in significantly

improved pain and radiographic measures. These results suggest that

a viable technique exists for treating spondylolisthesis without the need

for a formal posterior decompression.

FDA DEVICE/DRUG STATUS: InFuse: Not approved for this indica-

tion; Pedicle screws: Approved for this indication.

doi: 10.1016/j.spinee.2010.07.142

113. Single Level Lumbar Fusion at L5-S1: A Comparison of MIS

TLIF and AxiaLIF

W.B. Rodgers, MD, Edward J. Gerber, PA-C; Spine Midwest, Jefferson

City, MO, USA

BACKGROUND CONTEXT: MIS fusion techniques are becoming ac-

cepted as viable alternatives to traditional open techniques. The lumbo-sacral

junction remains a challenging fusion site. In this report, we compare our

experience using two alternatives to open fusion at the LS junction: MIS

T/PLIF and AxiaLIF.

PURPOSE: Results of the MIS T/PLIF procedure were compared with

those from the AxiaLIF procedure in to contrast the safety and effective-

ness of each minimally invasive transsacral fusion alternative.

STUDY DESIGN/SETTING: Prospective, nonrandomized clinical and

radiographic assessment.

PATIENT SAMPLE: Data were collected and reviewed on the first 50 pa-

tients (25 MIS T/PLIF, 25 AxiaLIF) who underwent minimally invasive

transsacral fusion.

OUTCOME MEASURES: Clinical and radiographic measures were

evaluated to assess surgical details, hospital stay, complication rates, and

pain scores.

METHODS: Data were collected on the first 50 patients (25 MIS T/PLIF,

25 AxiaLIF) treated by a single surgeon for single level fusion at the LS

junction using two alternative MIS techniques. The first 25 patients

(11 M, 14F, age 48.7 yrs, BMI 30.8) were treated with MIS T/PLIF and

the second 25 (13 M, 12 F; age 51.4 yrs, BMI 31.4)with AxiaLIF. Out-

comes and complications are reported, including early 12 mo. postop data

(MIS T/PLIF group n518; AxiaLIF group n57).

RESULTS: In the MIS T/PLIF group, OR time averaged 102.8 min, he-

moglobin change 2.0 g, and length of stay 1.69 days. Disk height increased

2.9 mm from preop to postop with 0.9 mm settling at 6 and 12 months; lis-

thesis (10 pts) decreased 1.2 mm from preop to postop with maintenance of

reduction at 6 and 12 months; Lenke scores measured 2.2 at 3 months, 1.5

at 6 months, and 1.5 at 12 months. VAS improved from 8.1 to 3.1 postop

but was 3.2 by 6 and 12 months. There were four complications in this

group: one deep infection, one broken instrument (radial disk cutter) re-

quiring anterior removal, one neuropraxia, and one transfusion. One pa-

tient died of unrelated causes at 3 months postop. In the AxiaLIF group,

OR time averaged 68.8 min, hemoglobin change 1.7 g, and LOS 0.92 days.

Disk height increased to 7.8 mmat postopwith 1.0 mm settling by 6mos and

1.9 mm settling at 12 months; listhesis (17 pts) decreased 4 mmwith loss of

ting and will be included with the post-meeting online content.