152S Proceedings of the NASS 23rd Annual Meeting / The Spine Journal 8 (2008) 1S–191S

P105. Maverick Retrieval Experience Using a Minimally Invasive

Technique in Varying Lumbar Levels

Luiz Pimenta, MD, PhD, Juliano Lhamby, BD, Juliano Fratezi, Sr., MD,

Carlos Arias, MD, Tomas Schaffa, MD, Leonardo Oliveira, MS; Sao Paulo,

Brazil

BACKGROUND CONTEXT: The inclusion of new techniques in the ther-

apeutic arsenal generates new solutions but also new problems. The benefits

of an artificial intervertebral disc include alleviation of pain through restora-

tion of height and stability of the affected spinal segment. In addition, by

maintaining normal or close to normal range of motion, the risk of adjacent

segment degeneration is thought to be lessened. But when revision is neces-

sary, it’s a demanding procedure. Indications to revise the Maverick device

may include implant loosening, malpositioning, displacement, early wear

and infection. Each indication will likely require different preoperative plan-

ning, testing, and strategies. An organized retrieval approach reduces opera-

tive time, minimizes risks, decreases stress and increases the success rate.

PURPOSE: Our strategies for Maverick retrieval have included lateral

(XLIF) removal with subsequent fusion using the same approach.

STUDY DESIGN/ SETTING: maverick TDR revision cases, using a min-

imal invasive XLIF (Extreme lateral interbody fusion) approach through

psoas muscle proving the safety of this access in avoiding vascular struc-

tures and scar tissue. The indications criteria included: persistent lumbar

pain, migration and dislocation of device. Patients ranged in age from

32–50 years old (mean 44.8 y/o). Levels of surgery included, L3/L4 and

L4/L5. VAS and ODI scores were collected to determine clinical outcomes.

PATIENT SAMPLE: 5 disc Maverick prothesis retrival.

OUTCOME MEASURES: VAS and ODI) outcomes clinical assessment

and radiografics mensuraments.

METHODS: five maverick TDR revision cases, using a minimal invasive

XLIF (Extreme lateral interbody fusion) approach through psoas muscle

proving the safety of this access in avoiding vascular structures and scar

tissue. The indications criteria included: persistent lumbar pain, migration

and dislocation of device. Patients ranged in age from 32–50 years old

(mean 44.8 y/o). Levels of surgery included, L3/L4 and L4/L5. VAS and

ODI scores were collected to determine clinical outcomes.

RESULTS: The five patients were successfully revised with fusion proce-

dures by a minimally invasive XLIF approach complemented with pedicle

screws without surgical complications. Mean surgical time was 89,4 min-

utes; mean blood loss was!50 ml, and all were outpatient surgeries. All pa-

tients after re-operations showed improvements in the clinical (VAS and

ODI) outcomes assessment, with solid fusion after two years follow-up.

CONCLUSIONS: Retrieval surgery in failed TDR is a demanding proce-

dure, often technically difficult, and carries an incidence of morbidity.

Therefore, to achieve the best results, a meticulous plan should be made

and surgically executed with care and precision. The XLIF procedure is

a safe and effective strategy for minimally disruptive Maverick TDR

removal at the L3/L4 and L4/L5 levels. Careful and appropriate patient

selection is essential in ensuring optimal outcomes.

FDA DEVICE/DRUG STATUS: Maverick Disc Prosthesis: Approved for

this indication.

doi:10.1016/j.spinee.2008.06.351

P106. Severely Polytraumatized Patients with and without Spinal

Injury Presenting to a Level I Trauma Institution

Albert Yee, MD, FRCSC1, Edward Lansang, Jr., MD2, Olivia Murnaghan3,

Iris Weller1, Yigal Bronstein, MD4, Michael Ford, MD1, Joel Finkelstein,

MD1; 1University of Toronto, Toronto, Ontario, Canada; 2Sunnybrook

Health Sciences Centre, Toronto, Ontario, Canada; 3McMaster University,

Hamilton, Ontario, Canada; 4Haddasa Medical Center, Beit-Shemesh,

Israel

BACKGROUND CONTEXT: Spinal trauma can have a significant neg-

ative effect on the morbidity, mortality and other outcomes of polytrauma

patients. There is limited literature whether spinal trauma adversely affects

the outcome of severely polytraumatized patients.

PURPOSE: The purpose of this study is to determine whether there are

differences in early hospital outcomes, morbidity and mortality in poly-

traumatized patients with Injury Severity Score (ISS) O/5 14, with or

without spinal fractures.

STUDY DESIGN/ SETTING: This is a case-control study conducted at

a Level 1 Trauma institution.

PATIENT SAMPLE: Polytraumatized patients with spinal injury and ISS

O/5 14 admitted between 1998 and 2005 were included. Age-, sex-, and

ISS-matched controls were identified from the Sunnybrook trauma

registry.

OUTCOME MEASURES: Outcomes that were measured included

length of ventilation, length of ICU stay, length of hospital stay, number

of operations and mortality.

METHODS: The Sunnybrook trauma registry was used to identify con-

secutive polytraumatized patients with spinal injury (ISSO14) admitted be-

tween 1998–2005. A matched control group (age, gender, ISS) without

spinal injury was assembled. Data was then collected from the medical

charts. The data was organized tabulated in a spreadsheet and subsequently

analyzed. Patient demographics were also tabulated for both groups. For

the spine group, the neurologic injury, fracture grade and treatment data

were also gathered.

RESULTS: There were a total of 290 patients (151 spinal, 139 control).

Spine injured patients spent more days ventilated (5.1d vs 2.4d) and expe-

rienced both a longer ICU (10.4d vs. 5.4d) and hospital stay (25.7d vs

16.2d). They also underwent more operations (1.2 vs 0.8) and more surgi-

cal procedures (1.5 vs 1.2). There was a trend toward greater mortality

(15% vs 9%) in the control group. The mortality rates of patients with

moderate-to-severe neurology (frankel A,B), mild-and-no-neurology

(frankel C,D,E) and the control were also compared (14% vs 8% vs

15%). Similarly, a comparison of mortality rates of low grade (AO grade

A) spine injury, high grade (AO grade B,C) spine injury and control group

was also done (8% vs 10% vs 15). Within the spine group, neurologic in-

jury occurred in 31% Fracture severity by AO grade showed 44% grade A,

29% grade B and 27% grade C. Thirty five percent of patients were treated

surgically. A higher AO-grade was associated with greater neurologic dys-

function, higher surgical rate and longer hospital stay. Neither Frankel

grade (A to E) nor AO-grade (A,B,C) correlated with early acute hospital

mortality.

CONCLUSIONS: Patients presenting with spinal injury in the face of

severe polytrauma appear to have a longer ICU stay and requirement for

ventilation when compared to those patients without spinal injury. The in-

cidence of neurologic injury and multilevel injuries in the spine group are

a reflection of higher energy trauma typically sustained by severely poly-

traumatized patients. As such, a high index of suspicion is warranted in the

evaluation of spinal injury and in clearance of the spine in patients present-

ing with an ISSO14.

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

any applicable devices or drugs.

doi:10.1016/j.spinee.2008.06.352

P107. Radiographic Histologic and Specimen Evaluation of Cervical

Nitinol Staples in a Goat Model

Robert Johnson, MD1, Karl Swann, MD1, Albert Sanders, MD1,

Matthew Swann2; 1San Antonio, TX, USA; 2Washington, DC, USA

BACKGROUND CONTEXT: Surgery may be indicated for cervical de-

generative disc disease in individuals that have failed conventional medical

management, and usually involves anterior cervical discectomy and fusion

with a plate/screw construct. A long term complication is pseudoarthrosis.

The pseudoarthrosis rate has been reported as 3% to 26%. Advances in

nitinol technology have made shape-memory nitinol more attractive for

orthopedic applications. Nitinol is a Nickel-Titanium alloy that can change