138S Proceedings of the NASS 23rd Annual Meeting / The Spine Journal 8 (2008) 1S–191S

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

any applicable devices or drugs.

doi:10.1016/j.spinee.2008.06.319

P76. Microdiscectomy for the Treatment of Recurrent Disc

Herniation

Marcelo Valacco, MD1, Marcelo Gruenberg, MD2, Carlos Sola, MD3,

MatıAs Petracchi, MD1; 1Buenos Aires, Argentina; 2Capital Federal, Buenos

Aires, Argentina; 3Hospital Italiano Buenos Aires, Buenos Aires, Argentina

BACKGROUND CONTEXT: A recurrent disc herniation is a well recog-

nized complication after lumbar microdiscectomy. When the revision surgery

is the option, some authors prefer to perform a discectomy followed by arthrod-

esis or dynamic stabilization, while others advocate the microdiscectomy.

PURPOSE: To compare the clinical results between two groups of pa-

tients, one for primary disc herniation and the other for recurrent disc her-

niation, both treated with microdiscectomy.

STUDY DESIGN/ SETTING: A retrospective clinical study.

PATIENT SAMPLE: A total of 50 patients in two groups who had under-

gone microdiscectomies were surveyed to asses their clinical outcomes.

All medical and surgical records were analized in both groups including

pain free interval, average age, gender, weight, perioperative complica-

tions, surgical time, and postsurgery hospital stay.

OUTCOME MEASURES: Clinical outcomes were assessed based on

Prolo’s scale.

METHODS: We retrospectively evaluated 2 groups of patients

after microdiscectomies, done by the same group of surgeons in the same

hospital. One group was conformed by 23 patients with recurrent disc herni-

ation operated on between May 1996 and March 2003 (Group A). The other

group was conformed by 27 patients operated on between May and October

1998 for primary disc herniation (Group B).

RESULTS: According to Prolo’s functional scale used at final evaluation, the

result was good in 13 patients (62%), poor in 3 (14%), and fair in 5 (24%) in

group A, and 19 patients were graded as good (79%), 4 poor (17%) and 1 fair

(4%) in group B. There were three complications in the group A, and there were

no complications in the group B. The weight of the patients was significantly

higher in the group with recurrence, perhaps may be inferred that the overweight

patients are more prone to suffer a relapse, but the small number of patients and

lack of other parameters (height, and corporal index), we can not be conclusive.

CONCLUSIONS: In our small series there was no statistical difference in

the functional evaluation between both groups. Microdiscectomy can be

considered as the first surgical option for the treatment of a recurrent disc

herniation. Future studies are required to understand the risk factors for re-

current disc herniation and the fair result after microdiscectomy.

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

any applicable devices or drugs.

doi:10.1016/j.spinee.2008.06.321

P77. Correction of Degenerative Adult Scoliosis in Patients

Undergoing Selective Transforaminal Lumbar Interbody Fusion

Ewell Nelson, MD1, Alan Villavicencio, MD1, Sigita Burneikiene, MD1,

Cassandra Roeca, BA2; 1Boulder Neurosurgical Associates, Boulder, CO,

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

BACKGROUND CONTEXT: Adult scoliosis is a multifaceted disease

accompanied by spinal rigidity, stenosis and severe, progressive back pain

and degeneration. Scoliotic deformities can be corrected via anterior and/

or posterior surgical approaches. Utilizing a single posterior TLIF (Trans-

foraminal Lumbar Interbody Fusion) approach theoretically minimizes

risks to the patient typically associated with an anterior procedure.

PURPOSE: The purpose of this study was to analyze the safety and fea-

sibility for TLIF surgical approach in this unique patient population.

STUDY DESIGN/ SETTING: A retrospective chart review study was

performed.

PATIENT SAMPLE: Patients with back pain as a result of degenerative

scoliosis with or without disc herniation, spondylolisthesis and/or central

canal stenosis were included in this study. The levels chosen to undergo

TLIF were based on clinical and/or radiographic findings. The number

of levels ranged from 1 to 3. Twenty-one scoliosis patients were included

in this study and followed for an average of 36 months (range 32–47).

Mean patient age was 63 years (range 45–77).

OUTCOME MEASURES: Cobb angle was used to measure correction of

the deformity. Clinical outcome (self-reported measures, e.g., patient satisfac-

tion, MacNab’s criteria), operative data (operative time, estimated blood loss),

hospitalization time, additional surgeries, and complications were assessed.

METHODS: Patients underwent a selective TLIF with a longer instru-

mentation and posterolateral construct.

RESULTS: The mean pre-operative coronal Cobb angle was 25.2 degrees

(range 9–52) compared to the mean of 10.1 degrees (range 1–35) post-operati-

velly, P50.0007. Clinical outcome defined as patients’ perceived overall treat-

ment effect was excellent/good in 19 (91%) of patients. The overall patient

satisfaction rate was 77%. Additional surgical procedures were performed in

two patients, one for a failed fusion and one for hardware removal because of

radiculopathy. The mean operative time was 388 minutes (range 275–501).

The mean estimated blood loss was 1142 mL (range 250–2500) and hospitali-

zation time was 7.3 days (range 2–16). Complications included cerebrospinal

fluid leaks (4), pseudoarthrosis (2), pedicle screw malposition (1), deep venous

thrombosis (1), pulmonary embolism (1), hematoma (1), and illeus (1).

CONCLUSIONS: This study implies that the TLIF surgical technique is

feasible, safe and an effective alternative to anterior-posterior reconstructive

surgery in adult patients with degenerative scoliosis and spinal stenosis.

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

any applicable devices or drugs.

doi:10.1016/j.spinee.2008.06.322

P78. Effect of Allograft Bone Processing on Structural Cortical

Grafts: A Comparison of Three Proprietary Processing Methods

Michael Dunn, PhD1, Moonhae Sunwoo, PhD2, Wilton Reynoso2,

Evangelia Chnari, PhD2, Jeffrey Cartmell, PhD2, Arthur Gertzman2;1University of Medicine and Dentistry of New Jersey, New Brunswick, NJ,

USA; 2Musculoskeletal Transplant Foundation, Edison, NJ, USA

BACKGROUND CONTEXT: Machined cortical bone is routinely uti-

lized for spinal fixation. The processing of cortical bone, intended to re-

move undesirable immunologically active elements, may also remove

139SProceedings of the NASS 23rd Annual Meeting / The Spine Journal 8 (2008) 1S–191S

desirable elements and affect the bone’s ability to undergo bone remodel-

ing by the mechanism of creeping substitution. The osteoinductive poten-

tial of cortical bone is utilized during creeping substitution, via

mechanisms of action similar to demineralized bone.

PURPOSE: Accordingly, we elected to evaluate the latent osteoinductive

property of cortical bone by making a demineralized bone matrix and mea-

suring BMP-2 content and osteoinductive properties. It was our hypothesis

that bone cleaning and processing protocols impact the inherent ability of

the bone to reincorporate (as determined by measuring osteoinductive po-

tential and BMP-2 content).

STUDY DESIGN/ SETTING: Basic Science.

OUTCOME MEASURES: Osteoinduction.

METHODS: The following groups were used: 1) MTF ATP� treated tis-

sue, 2) RTI BioCleanse� treated tissue, 3) LifeNet Allowash� treated tis-

sue. Tissue from each treatment group was made into a formulation of

DBM (using acid demineralization based upon standard techniques1)

and normal saline (0.9% Sodium Chloride, Irrigation, USP). Samples from

each group were analyzed in triplicate for BMP-2 content via ELISA.

Samples (N58/group; 20–25 mg each) were also randomized and im-

planted bilaterally in the hamstring muscles of athymic nude mice. Ani-

mals were sacrificed at 4 weeks post-implantation. Explanted samples

were decalcified, stained with H&E and evaluated blindly for osteoinduc-

tivity (OI) utilizing a semi-quantitative scoring system (Table).

RESULTS: Osteoinductivity: DBM prepared from MTF ATP treated cortical

tissue was consistently osteoinductive in this model; 7 out of 7 ranked samples

were osteoinductive (1 sample could not be ranked due to histological artifacts),

with an average bone score of 2.1760.82. Two-sample t-tests demonstrated that

the MTFATP samples were significantly more osteoinductive than both the Bi-

oCleanse and AlloWash sample groups (p!0.05). DBM prepared from RTI Bi-

oCleanse cortical tissue was not osteoinductive in this model; 7 out of 7 ranked

samples were not osteoinductive (1 sample could not be ranked due to histolog-

ical artifacts). The average bone score was 0.0060.00. DBM prepared from

LifeNet Allowash cortical tissue was partially osteoinductive in this model; 3

out of 7 ranked samples were osteoinductive (1 sample could not be ranked

due to histological artifacts). The average bone score was 0.5760.74 BMP-2:

The MTF ATP group demonstrated significantly more BMP-2 (13,9656435

pg/g DBM) than the RTI BioCleanse and LifeNet AlloWash tissue (2982644

pg/g and 20826148 pg/g, respectively) using 1-Way ANOVA (p!0.05).

CONCLUSIONS: The higher BMP-2 content and osteoinductivity of

DBM prepared from ATP tissue compared to DBM prepared from Bio-

Cleanse and Allowash treated tissue may result in improved incorporation

of allografts treated with the ATP process. These results support the hy-

pothesis that bone-cleaning processes may have an impact on the inherent

ability of the cortical bone to reincorporate.

Table. OI Scoring Scale

FDA DEVICE/DRUG STATUS: All cortical tissue (MTF ATP�, RTI Bio-

Cleanse�, LifeNet AlloWash�) has HcT/P status: Approved for this indication.

doi:10.1016/j.spinee.2008.06.323

P79. Dose-escalation Placebo-controlled Local Histopathology

Following Intraligamentous Lumbosacral Injections in Swine of

a Drug Commonly Used in Prolotherapy for Low Back Pain

Simon Dagenais, DC, PhD1, John Mayer, DC, PhD2, Scott Haldeman, DC,

MD, PhD3, Mark Hite, PhD, DABT4, James Wooley, DC1; 1Irvine, CA,

USA; 2Tampa, FL, USA; 3Santa Ana, CA, USA; 4Blue Bell, PA, USA

BACKGROUND CONTEXT: A drug commonly used in prolotherapy

(Proliferol) for chronic low back pain contains lidocaine hydrochloride

0.25%, dextrose 12.5%, glycerin 12.5%, and phenol 1.0%. Despite ex-

tensive clinical experience in humans with this formulation, little is known

about its local histopathology effects on the lumbosacral ligaments and

other soft tissues adjacent to the injection sites.

PURPOSE: To assess the local histopathology effects of Proliferol follow-

ing intraligamentous lumbosacral injections.

STUDY DESIGN/ SETTING: Dose-escalating, placebo-controlled local

histopathology study.

PATIENT SAMPLE: Test animals were 48 Yucatan mini swine.

OUTCOME MEASURES: Microscopic histopathology at injection sites

following 24 hours and 14 days of recovery.

METHODS: Swine were randomly assigned to 4 study groups (6 males/6

females per group) 1. high dose placebo (0.9% saline); 2. low dose; 3. me-

dium dose; 4. high dose. The low dose was 0.25mL/kg, equivalent to 20mL

in an 80kg human (1X); medium dose was 5X, and high dose was 10X.

Injections were made into the interspinous, supraspinous, sacroiliac, sacro-

tuberous, and iliolumbar ligaments, as well as the intra-articular facet joint

capsules, and sacroiliac ligaments and joints to mimic current clinical use

in humans. Tissue samples of the L4-L5 and L5-L6 interspinous ligaments,

as well as the sacroiliac ligaments, were examined in all groups.

RESULTS: At 24 hours, there were microscopic findings of minimal to mod-

erate subcutaneous hemorrhage, as well as hemorrhage, inflammation, and

necrosis in the L4-L5 and L5-L6 interspinous ligaments and adjacent skeletal

muscle, which were most evident in the medium and high dose groups. There

were no significant findings in the sacroiliac ligaments. After 14 days of re-

covery, there remained substantial subacute or granulomatous inflammation

and degeneration in the L4-L5 and L5-L6 interspinous ligaments and adja-

cent skeletal muscle, as well as vascular inflammation or fibrinoid degener-

ation in adjacent arteries. There was also evidence of soft tissue repair

underway, including fibrosis and skeletal muscle regeneration.

CONCLUSIONS: Injections of 5X and 10X the human clinical dose of Pro-

liferol in lumbosacral ligaments of swine elicited localized acute inflammatory

soft tissue changes at the injection sites after 24 hours, with subsequent evi-

dence of soft tissue repair after 14 days of recovery. These histopathology find-

ings are consistent with the proposed mechanism of action for this intervention.

FDA DEVICE/DRUG STATUS: Proliferol: Investigational/Not approved.

doi:10.1016/j.spinee.2008.06.324

P80. Resiniferatoxin Induced Alteration of Neurotrophic Factors in

the Dorsal Root Ganglia of Allodynic Rats

Jian-Guo Cui, MD, PhD, Gabriel Tender, MD, Yuan-Yuan Li,

Nicolas Bazan; New Orleans, LA, USA

BACKGROUND CONTEXT: Vanilloid receptor 1 (VR1) is expressed only

on C-fiber and A-delta-fiber neurons, mediates various noxious stimuli (capsa-

icin, heat, protons), and acts as a molecular integrator for nociception. Resin-

iferatoxin (RTX) is a potent and specific VR1 agonist that selectively

eliminates VR1-positive neurons. Our previous study suggested that RTX in-

jection into the dorsal root ganglia (DRG) improves tactile allodynia and sup-

presses thermal hyperalgesia. Immunohistochemistry examinationshowed that

suppression of tactile allodynia and thermal hyperalgesia was associated with

the extent of elimination of VR1 positive neurons. Our current study aims to

define the neurophic factor changes after VR1-positive neuronal elimination.

PURPOSE: PURPOSE: Define the alteration of neurotrophic factors and

their possible function following RTX injection into the DRGs in neuro-

pathic rats.

METHODS: Twenty-four rats were subjected to a photochemically induced

sciatic nerve injury. The rats that developed tactile allodynia and hyperalge-

sia were treated by RTX injection in the ipsilateral L3-L6 DRGs. Mechanical

allodynia was tested by measuring the paw-withdrawal response to mechan-

ical stimuli (von Frey filaments ranging from 1 to 26 g). If a filament induces

3 paw withdrawals out of 5 stimuli, the value of the filament in grams was