45SProceedings of the NASS 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S

Thursday, October 7, 20103:50–4:50 PM

Concurrent Session 2: Lumbar

97. Prospective, Multi-Center, Randomized, Controlled Study

of Anular Repair in Lumbar Discectomy: Preliminary Observations

Alexander Bailey, MD1, Glenn Amundson, MD1, Scott Blumenthal, MD2,

Mokbel Chedid, MD3, Richard Guyer, MD2, Jeffrey S. Gerdes, MD4,

Julie Messer5, Steven L. Griffith, PhD5; 1Heartland Spine and Specialty

Hospital, Overland Park, KS, USA; 2Texas Back Institute, Plano, TX, USA;3Henry Ford Medical Group, Detroit, MI, USA; 4Central Minnesota

Neuroscience, St Cloud, MN, USA; 5Anulex Technologies, Minnetonka,

MN, USA

BACKGROUND CONTEXT: Lumbar discectomy is generally per-

ceived to be a successful operation for the treatment of symptomatic her-

niations with positive outcomes in 75 to 80% of patients. Repair of the

anulus fibrosus thus closing the pathway for recurrent herniation has been

proposed as an adjunctive method to further improve outcomes by miti-

gating the need for subsequent surgery. Retrospective clinical series have

been reported demonstrating a clinically relevant reduction in reopera-

tions when anular repair is performed, but no multi-center, prospective,

randomized, controlled clinical trial has been published specifically eval-

uating this unique additional technique that could positively impact

outcomes.

PURPOSE: The purpose of this study was to examine the treatment effect

of repairing the anulus fibrosus adjunctive to lumbar discectomy for the

surgical management of herniated nucleus pulposus.

STUDY DESIGN/SETTING: A prospective, single-blind, randomized,

controlled clinical trial conducted at 34 clinical sites with 58 investigative

surgeons.

PATIENT SAMPLE: Seven hundred and twenty-three patients were sur-

gically treated for herniated lumbar discs and randomly assigned in a 2:1

schema to discectomy with anular repair (n5475) or discectomy without

anular repair (n5248). Preliminary observations in this study are drawn

from one-year clinical data from three hundred and twenty (44.3%) of

the enrolled study cohort.

OUTCOME MEASURES: Patient self-reported measures were used in

this study; eg, visual analog scales (VAS) for leg and back pain, Oswes-

try Disability Index, and Short Form-12 (SF-12). Adverse events, com-

plications, and subsequent surgeries were documented. Of primary

interest was the need for any secondary surgical intervention for recur-

rent herniation.

METHODS: Patients consented for the study were randomly assigned af-

ter intraoperative completion of their discectomy to either anular repair

(using Xclose� Tissue Repair System, Anulex Technologies, Minnetonka

MN) or no anular repair. Pre-operative outcome measures were compared

to follow-ups at 2 weeks, 6 months, 12 months, and 24 months. Any sec-

ondary surgery was noted and categorized according to the diagnosis for

reoperation with particular interest on those performed for recurrent herni-

ation at the same lumbar level and on the same side.

RESULTS: Anular repair with this particular implant was deemed appro-

priate in 85% of patients screened for the study and when attempted, repair

of the anulus was successfully performed in over 95% of cases. Patient

symptoms were improved after surgery in an equivalent manner after dis-

cectomy with or without anular repair. There was no added risk of needing

a secondary surgery when this anular repair implant was used; and there

was an overall decrease, although not statistically significant, in all subse-

quent surgeries for any diagnosis. Overall, there was a 40% reduction in

the risk of needing a second surgery for recurrent herniation when anular

repair was performed (p50.131). Furthermore, with surgeon investigators

with large numbers of discectomy cases, the reduction in risk improved to

50% (p50.049).

CONCLUSIONS: This is the first and largest multi-center randomized

study demonstrating a positive treatment benefit for an anular repair

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

implant or technique. The ability to close anular defects and prevent

disc material re-extrusion can reduce the need for subsequent surgery

while not negatively impacting patient symptom relief or functional

improvement.

FDA DEVICE/DRUG STATUS: Xclose Tissue Repair System: Approved

for this indication.

doi: 10.1016/j.spinee.2010.07.125

98. Results of Bacterial Culture from Surgically Excised

Intervertebral Disc in 52 Patients Undergoing Primary Lumbar

Microdiscectomy at a Single Level

Vijay J. Agarwal, MD1, Ray Golish, MD1, Dimitriy Kondrashov, MD2,

Todd F. Alamin, MD1; 1Stanford University, Palo Alto, CA, USA;2St. Mary’s Spine Center, San Francisco, CA, USA

BACKGROUND CONTEXT: The pathogenesis of lumbar disc disease is

complex. At the molecular and cellular levels, a cascade has been eluci-

dated which involves inflammatory mediators and cytokines, structural

matrix proteins and their fragments, and proteases and their inhibitors.

Mechanical and genetic factors also play a role in the spectrum of disc dis-

ease, from herniated nucleus pulposus (HNP) to end stage degenerative

disc disease with loss of height. Less attention has been given to possible

microbial pathogens as an etiologic factor in HNP.

PURPOSE: To determine the prevalence of positive bacterial cultures in

the disc material of immunocompetent patients without diabetes mellitus

or other immune compromise.

STUDY DESIGN/SETTING: This study presents a consecutive case se-

ries from a single center of patients undergoing primary microdiscectomy

for lumbar herniated nucleus pulposus (HNP) who received microbiologic

laboratory culture of excised disc material.

PATIENT SAMPLE: A review lab cultures of excised disc material of 52

patients treated with microdiscecetomy for herniated nucleus pulposus. All

patients were from the San Francisco/Greater Bay Area, and were previ-

ously cleared with Institutional Review Board approval.

OUTCOME MEASURES: Excised nucleus pulposus samples were tested

via routine bacterial culture. Data was analyzed by t-test, Kolmogorov-

Smirnov test, and two-by-two contingency table analysis with Fisher exact

test. A priori power analysis was performed. The power of t-tests is 80%

for N550 subjects and alpha value of 0.05 assuming a large effect size

(Cohen’s d51.0).

METHODS: This case series included 52 patients with radiculopathy and

MRI positive for HNP who elected for lumbar microdiscectomy after fail-

ure of conservative management. All patients received primary surgery at

a single spinal level in the absence of diabetes mellitus, systemic steroid

use, chemotherapy, other immune compromise, or prior lumbar surgery.

Excised disc material was sent for routine bacterial culture. Samples were

incubated at 35 degrees Celsius for 5 days, under standard anaerobic con-

ditions, and aerobes incubated under 5% CO2.

RESULTS: Cultures were positive in 10 patients (19.2%). Propionibacte-

rium acnes was the sole organism isolated in 7 (13.5%), with Peptostrep-

tococcus and Staphylococcus species accounting for the remainder. There

were 24 females (46.2%) and 28 males (53.8%) with a mean age of 43.9

years (standard error 1.8). Duration of symptoms was greater than 12

weeks in 35 patients (67.3%). Onset of symptoms was insidious in 22 pa-

tients (42.3%), sudden in 16 (30.8%), and the history was unclear in the

remainder. Prior epidural steroid injection was received by 17 patients

(32.7%), and 11 patients had a history of smoking (21.2%). None of these

variables was significantly different in patients with positive and negative

cultures (pO0.05).

CONCLUSIONS: Bacteria, typically low-virulent strains, were isolated

in 19.2% of these patients that had no clinical signs of infection associ-

ated with their radiculopathy caused by HNP. Propionibacterium acnes

were isolated by routine laboratory culture of excised disc material in

13.5% of immunocompetent patients undergoing primary single level dis-

cectomy for radiculopathy with lumbar HNP. Previous studies have

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