127SProceedings of the NASS 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S

in Canada has not been assessed. The Canadian healthcare system provides

a unique opportunity to assess the impact of surgical volume on outcomes

as there is only a universally available healthcare system, in contrast to the

mixed private and public systems found in the USA, United Kingdom and

Australia.

PURPOSE: The purpose of the study was to assess the relationship

between the likelihood of adverse events related to surgery and the volume

of surgery for adolescent idiopathic scoliosis in Canada.

STUDY DESIGN/SETTING: A retrospective cohort study utilizing CI-

HI-DAD, a national validated administrative discharge database in Canada.

PATIENT SAMPLE: All 1225 patients in the CIHI-DAD with the

diagnosis of adolescent idiopathic scoliosis, aged 11–17, who underwent

a spinal fusion between 2003–2007 were included.

OUTCOME MEASURES: Inpatient mortality rate, length of stay and

adverse event rates as defined as wound infection, hematomas, neurologic

injury, hardware failure, homologous red blood cell transfusions.

METHODS: Demographic data and outcome measures were obtained

from the CIHI-DAD, with both univariate and logistic regression analysis

were performed to analyze the effect of hospital volume on outcome

measures.

RESULTS: There were no in hospital deaths among the 1225 AIS patients

who had fusion surgery. 57% were admitted to a post-operative intensive

care unit or step down unit with an average length of stay of 1.7 +/- 3.6

days. Average total length of stay in hospital was 7.9 +/- 7.4 days, with

over 98% of patients going home. Wound infection (1.47%) and wound

-hematomas(1.88%) and hardware failure (1.39%) were the most common

local complications. Neurologic injury was rare (0.49%). Systemic compli-

cations such as DVT, pneumonia and cardiac arrhythmias were also rare

(0.08%, 0.33% and 0.16%). 32.57% of patients received red blood cell

transfusion. Wound infection rates varied inversely with increasing quan-

tiles of surgical volume (OR 0.54 [0.36, 0.819]). Not receiving red cell

transfusion varied inversely with increasing quantiles of surgical volume

(OR 1.21 [1.11, 1.31]). Overall, the odds of having any adverse event

following surgery, was significantly higher in surgical centers having the

lowest quantiles of surgical volume compared to centers with the highest

quantile (OR 2.62 [1.27,5.4]).

CONCLUSIONS: Overall, rates of both local and systemic adverse events

are low. However, wound infection rates and red blood cell transfusions

and overall adverse events decrease with increasing quantiles of surgical

volume in adolescent idiopathic scoliosis. In a publicly funded health

system, with universal coverage, centralization of centers performing

AIS surgery has the potential to reduce adverse events such as wound

infections and red cell transfusion.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2010.07.330

P55. Prospective, Randomized Controlled Study of Repairing the

Anulus Fibrosus after Lumbar Discectomy: A Single Surgeon’s

Experience

Alexander Bailey, MD1, Julie Messer2, Steven L. Griffith, PhD2;1Heartland Spine and Specialty Hospital, Overland Park, KS, USA;2Anulex Technologies, Minnetonka, MN, USA

BACKGROUND CONTEXT: Lumbar micro-discectomy is considered to

be a relatively safe and successful surgery. The current practice of leaving

an open defect in the anulus fibrosus at the conclusion of a lumbar discec-

tomy may lead to an increased potential for re-herniation which may result

in additional surgery. Repair of the defect in the anulus appears to be a rea-

sonable and logical approach to mitigate this outcome and possibly reduce

the incidence of reoperation for recurrent herniated nucleus pulposus.

PURPOSE: This study investigates the perceived benefits of repairing the

anulus fibrosus.

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

STUDY DESIGN/SETTING: Prospective, randomized, controlled study

from a single surgeon.

PATIENT SAMPLE: Sixty-six patients were screened for enrollment into

this prospective study.

OUTCOMEMEASURES: The Oswestry Disability Index, the SF-12 and

visual analog scales (VAS) for both low back and leg pain were collected.

All complications, including the need for additional surgery, are also

noted.

METHODS: Patient informed consent allowed for intra-operative ran-

domization at the conclusion of standard discectomy techniques in 2:1

manner, anular repair with Xclose Tissue Repair System (Anulex Technol-

ogies Inc, Minnetonka MN) vs. no repair, respectively. In this ongoing

study, patient outcomes are determined pre-operatively as well as 2 weeks

(n563), 6 months (n547), 12 months (n534) and 18 months (n57). Over-

all average time from surgery was 14.6 months (range: 2.3 to 23.8 months).

RESULTS: Of the 66 patients screened for enrollment, 3 were excluded

intra-operatively (due to concerns of poor tissue quality); in three others,

anular repair was unsuccessfully attempted. Randomization resulted in

44 patients receiving anular repair (AR group) and 16 patients receiving

no anular repair (NAR group). Patient outcomes showed a similar improve-

ment in both groups immediately after surgery that was maintained

throughout the follow-up periods. There were a total of seven cases that

required additional surgery (11.1%). One of the three attempted (but un-

successful) repair required a second surgery, and the NAR group had

two reoperations (12.5%). In the attempt to treat group and the NAR

group, all reoperations were for recurrent herniated nucleus pulposus;

same level, same side, and same location (true recurrent herniation). Four

patients in the AR group required additional surgery (9.1%). The AR group

had two reoperations for recurrent herniated nucleus pulposus (4.5%). One

additional patient developed a far lateral herniation remote from previous

herniated disc and repair and the other patient required fusion for post-

laminectomy syndrome/degenerative disc disease. The reduction in inci-

dence of surgery for true recurrent herniations was 64.0%. Using the most

conservative methods, the reduction in additional surgery, regardless of

reason, was 27.2%.

CONCLUSIONS: Anular repair using Xclose Tissue Repair System can

be successfully accomplished in greater than 90% of cases if the discec-

tomy is performed with the ultimate goal of repair being appreciated.

Repairing the anulus fibrosus was shown to be beneficial by reducing

the need for additional surgery, in particular those re-operations for true

recurrent herniation.

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

for this indication.

doi: 10.1016/j.spinee.2010.07.331

P56. Rating the Whole Person Impairment Due to the Spine and the

Pain Disability Status of Individuals with Polytrauma History over

2 Years, According to the AMA Guides to the Evaluation of

Permanent Impairment, Sixth Edition

Armando S. Miciano, MD; Nevada Rehabilitation Institute, Las Vegas, NV,

USA

BACKGROUND CONTEXT: There has been no systematic research on

the reliability of the Whole Person Impairment Rating due to the Spine

(WPIS) or the pain-related impairment (PRI) system developed for the

Sixth edition of the AMA Guides to the Evaluation of Permanent Impair-

ment, or of any other system for evaluating WPIS or PRI.

PURPOSE: The objective is to examine the pain-related impairment (PRI)

of polytrauma patients with chronic pain (CP) and with a spine impairment

using the Pain Disability Questionnaire (PDQ), a formal assessment of

pain disability by the AMA Guides to Evaluation of Permanent Impair-

ment, Sixth Edition.

STUDY DESIGN/SETTING: A cross-sectional case series study was un-

dertaken in a referral-based outpatient rehabilitation clinic.

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