Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S 13S

computerized tomography images in the plane passing through the centerof L3-L4 and L4-L5 pedicles on both right and left sides were obtainedfrom the specimens. The cross-sectional areas of the intervertebral foraminaat L34 and L45 were measured with the Aquarius Image software in CT.The images were then transferred to computer, and disc space narrowingof L34 and L45 levels with 1-mm incremental displacements was performedthrough Microsoft paint software. With the scale set the same as CT imagingsoftware’s scale, the cross-sectional areas of the intervertebral foramina atL34 and L45 and residual cross-sectional foraminal areas following 1, 2,3, 4, and 5 mm narrowing of the L34 and L45 disc space were measuredwith the NIH Image J software in computer. The mean and standard deviationvalues were calculated for all measured dimensions. Student’s t tests wereused to detect statistical differences in the cross-sectional areas at differentdegrees of disc space narrowing. The confidence level for significancewas p�.05.RESULTS: The mean normal cross-sectional areas of the intervertebralforamen were 179.26�31.00 mm2 for L3-4 level, 163.98�43.48 mm2 forL4-5 level. No significant difference was found between that measured onCT and the one on the computer (p�0.05). Compared with normal valuesof intervertebral foraminal areas, a decrease of about 8% of L34 and L45intervertebral foraminal areas was found respectively with each 1 mmincremental disc space narrowing. There were statistically significant differ-ences among the normal and residual cross-sectional foraminal areas follow-ing different degrees of disc space narrowing (p�.0001).CONCLUSIONS: There is a significant decrease in the size of neurofora-men following lumbar disc space narrowing. The size of the intervertebralforamen is directly related to the height of the disc space.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.026

12:0625. A prospective cohort analysis of adjacent vertebral body bonemineral density in lumbar surgery patients with or withoutinstrumented posterolateral fusion: a 9 to 12 year follow-upKern Singh, MD, Howard S. An, MD, Dino Samartzis, MD,Ahmad Nassr, Jason Provus, Margaret Hickey, Gunnar B.J. Andersson,MD, PhD; Department of Orthopedic Surgery, Rush University MedicalCenter, Chicago, IL, USA

BACKGROUND CONTEXT: No long-term prospective study has evalu-ated the effects of instrumented lumbar fusions on bone remodeling atadjacent vertebral levels. Several studies in animals and humans havereported a decrease in bone mineral density (BMD) at the adjacent levelduring the first 6 months after spinal fusion with a return to baseline at 1-year follow-up in up to 60% of patients.PURPOSE: To determine by dual energy X-ray absorptiometry (DEXA)long-term BMD changes that occur at the adjacent three levels above aninstrumented posterolateral lumbar fusion or an isolated laminotomy andlumbar discectomy.STUDY DESIGN/SETTING: A prospective, cohort study.PATIENT SAMPLE: A study of 11 patients who underwent either aposterior lumbar spinal fusion with instrumentation (n�7) or a lumbarlaminotomy and discectomy alone (n�4).OUTCOME MEASURES: BMD measured quantitatively by DEXAevaluation.METHODS: DEXA was performed initially at a mean postoperativefollow-up of 4.0 years (range, 2.3 to 5.5 years) and again at a mean of10.8 years (range, 9.1 to 12.4 years). Eleven patients were divided intotwo groups: laminotomy and discectomy (n�4) and instrumented posteriorspinal fusion (n�7). All patients underwent surgical procedures at the L4-L5 or L5-S1 levels with DEXA analysis being performed on the adjacentthree cephalad levels. The discectomy group (mean age, 57.8 years) under-went lumbar hemilaminotomy without fusion whereas the other group(mean age, 60 years) underwent pedicle-screw instrumentation and postero-lateral lumbar fusion. Peripheral sites, including the femoral neck, were

included in the DEXA analysis to normalize for individual differences inbone mineral metabolism.RESULTS: At the mean 10.8-year follow-up, the fusion group was noted tohave at the adjacent level, two levels cephalad, and three levels cephaladnormalized BMDs of 1.47, 1.39, and 1.27 respectively. A 14.8%, 10.8%,and 9.5% increase respectively in normalized BMD was observed whencompared with the mean 4-year fusion values (p�.05). This increasewas also noted on comparative T-score, Z-score, and absolute BMD values(p�.05). The discectomy group when evaluated revealed no statisticallysignificant change from the mean 4 to 10.8-year follow-up (BMD, normal-ized BMD, T-score, Z-score). No statistically significant difference wasnoted in hip BMD at the mean 4-year and 10.8-year follow-up (1.05vs. 1.03), suggesting that the effects were local.CONCLUSIONS: The local BMD adjacent to an instrumented lumbarfusion is increased at a mean of 10.8 years after surgery. There is agradual decrease in BMD changes with increasing distance from the fusionlevel. Alterations in fusion site biomechanics and modulus mismatchbetween the host bone and the spinal instrumentation most likely result inchronic, localized bone remodeling with an increased BMD that decreasesthe greater the distance from the fusion mass.DISCLOSURES: FDA device/drug: dual energy X-ray absorptiometry.Status: Approved for this indication. FDA device/drug: pedicle-screw in-strumentation. Status: Approved for this indication.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.027

Wednesday, September 28, 20053:59–4:42 PM

Concurrent Session: Lumbar Disc

3:5926. A retrospective study examining five-year post-surgical outcomesof virgin discectomy patientsWilliam Welch, MD1, Robert Gatchel, MD2*, Patricia Karausky, RN1,Harry Herkowitz, MD3, Dennis Maiman, MD4, Frank Phillips, MD5,F. Todd Wetzel, MD6, Eugene Carragee, MD7, Hallett Mathews, MD8;1University of Pittsburgh, Pittsburgh, PA, USA; 2Univ. Texas, Arlington,TX, USA; 3William Beaumont Hospital, Royal Oak, MI, USA; 4MedicalCollege of Wisconsin, Meqon, WI, USA; 5Rush University MedicalCenter, Chicago, IL, USA; 6Department of Orthopaedic Surgery, TempleUniversity, Philadelphia, PA, USA; 7Stanford University, Stanford, CA,USA; 8MidAtlantic Spine Specialists, Richmond, VA, USA

BACKGROUND CONTEXT: There is little research assessing the long-term outcome of discectomy surgery. Thus, this protocol was developedto collect five-year post-surgical outcomes of virgin discectomy subjects.PURPOSE: To define clinical outcomes, including how lumbar spinesurgery affected the subjects’ ability to manage everyday life at thattime, whether treatment the subjects received was helpful or harmful,whether additional treatment or surgery was needed after the initial surgery(discectomy), general health questions about how the subjects are feelingnow, and pain levels before and after surgery.STUDY DESIGN/SETTING: The design of this study involved question-naires that were given to eligible subjects either by telephone or mail.PATIENT SAMPLE: This was a multicenter, retrospective study. Anysubject, age 18 years or older, who had a virgin discectomy within theJanuary 1997 to March 1999 time period was considered. The sample wastaken from each participating physician’s patient base.OUTCOME MEASURES: The outcome measures included were: the SF-12; the Pain and Disability Questionnaire (PDQ); Treatment HelpfulnessQuestionnaire items; and a survey evaluating current health care forback pain.METHODS: All data were subsequently pooled at one site for statisticalanalysis. Descriptive statistics (means and percentages) were computed

Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S14S

distance and leg raising test by monthly examinations. The radiographicexaminations were performed every 3 years after treatment. Statisticalanalysis was performed with chi-square test.RESULTS: In patients who underwent surgery, low back pain and legpain disappeared shortly after surgery. Only one patient who underwentsurgery received second surgery due to persisting and/or recurring symp-toms. Tight hamstrings persisted postoperatively even after low back painand leg pain had disappeared. However, the symptoms gradually improvedwith regular stretching exercises and disappeared completely in all thepatients between 3 months and 1 year after surgery. None of the patientswho were followed up until adulthood suffered problems in daily life dueto recurrence of tight hamstrings. Of the 20 patients who reached adulthood,18 showed narrowing of the intervertebral space in the affected interverte-bral disc. However, none of these patients manifested lesions or instabilityin the adjacent disc. In 9 out of 12 patients who underwent conservativetreatment, low back pain and leg pain disappeared, but tight hamstringspersisted in 10 patients with the exception of two individuals. Adultpatients with persisting tight hamstrings experienced problems in theirmovements in daily living, especially those related to anteflexion of thetrunk. Of the 11 patients without surgery who reached adulthood, 6 showednarrowing of the intervertebral space in the affected intervertebral disc.CONCLUSIONS: Because conservative treatment often results in persis-tent tight hamstrings, it is important to eliminate the irritation of the nerveroots by surgery at an early stage.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.029

for all outcome variables, and compared with normative data. Statisticalanalyses of the confidence intervals associated with the subject cohortversus the normative databases were also conducted.RESULTS: A total of 53 subjects were evaluated. Outcome scores of thequestionnaires revealed that, in general, patients’ responses indicated thatthey felt well both mentally and physically, that there was a low level ofpain and functional disability, and that they were satisfied with the outcomeof their surgery. The SF-12 PCS, the overall physical component scale, was42.47. The SF-12 overall mental component was also in the normal rangeat 53.47. (50 is average in a normal population.) The PDQ, a measurementof pain and disability, was 41.1. The PDQ measurement of psychosocialfunction was 21.1 (range of 0 indicating no problem, up to 150 the greatestseverity). The Treatment Helpfulness Questionnaire was 49.8 (score of 50indicates good overall satisfaction with the surgery). Analyses of confidenceintervals revealed no significant differences between the subjects and nor-mative database values for any of the questionaire data. Finally, the repeatsurgery rate on the original site was only 9.8%.CONCLUSIONS: Because the lumbar discectomy has become one ofthe most common spinal surgical procedures performed in the U.S, we arecompelled to determine the long-term effects of this treatment modality.In looking at patients who are 5 years past the procedure and determiningtheir overall level of health and well-being, we can reveal treatment inade-quacies that require correction and can help identify methods to improveclinical outcomes both immediately and on a long-range basis. The presentresults are the first to demonstrate positive 5-year outcomes on a numberof important biopsychosocial variables.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.028

4:0527. Clinical course of tight hamstrings in children with lumbar discherniation following surgical or nonsurgical treatmentsShunji Matsunaga, MD, Yoshimi Nagatomo, MD, Takuya Yamamoto,MD, Kyoji Hayashi, MD, Kazunori Yone, MD, Setsuro Komiya, MD;Graduate School of Medical and Dental Sciences, KagoshimaUniversity, Kagoshima, Japan

BACKGROUND CONTEXT: Lumbar disc herniation in children is char-acterized by the presence of tight hamstrings, which disturbs their physicalactivities. However, there are few reports on long-term observations of theclinical course of tight hamstrings following treatment of pediatric lumbardisc herniation.PURPOSE: This study examined whether or not tight hamstrings hadimproved in pediatric patients with lumbar disc herniation following surgi-cal treatment, compared with patients who did not undergo surgery, toinvestigate the significance of surgery for tight hamstrings.STUDY DESIGN/SETTING: A controlled comparative study was per-formed prospectively.PATIENT SAMPLE: This study involved 37 patients who developedlumbar disc herniation under the age of 16 and who manifested tighthamstrings on initial examination. Twenty-five patients underwent Love’sdiscectomy. The mean postoperative follow-up period was 11 years and 5months, ranging from 5 to 19 years, during which 23 patients reachedadulthood. Twelve matched patients who exhibited same degree tight ham-strings were treated conservatively. The mean follow-up period of patientstreated conservatively was 10 years and 9 months, ranging from 3 to 12years, during which 11 patients reached adulthood. Patients of both groupunderwent streching exersise by the same protocol.OUTCOME MEASURES: Improvement of pain and tight hamstrings inpatients with surgery was compared with patients without surgery. Disabili-ties in daily life of adulthood caused by tight hamstrings and changes ofradiographic findings of lumbar spine were also reviewed.METHODS: Low back and leg pain was measured with a visual analoguescale. Tight hamstrings of the patients was measured with finger-floor

4:1128. An RCT of Orthotrac vest unloading vs.EZ brace—one-year outcomesJohn Triano, DC, PhD1, Carolyn Rogers, MS2, Jennifer Diedrich, BS3,Celeste Gonzalez2, Stephen Hoschschuler, MD4; 1University of Texas atArlington, Plano, TX, USA; 2Innovative Spinal Technologies, Plano, TX,USA; 3Innovative Spinal Technologies, TX, USA; 4Texas Back Institute,TX, USA

BACKGROUND CONTEXT: Patients with discopathy have leg pain dueto compression or chemical neuritis. Axial load causes reduction in canalcross-section. A load of 25–50% body weight longer than 5 min reducesarea to �100 mm2. A method that reduces axial load while weight bearingmay provide symptomatic relief.PURPOSE: This study evaluated the results after 1 year from Orthotracpneumatic vest (OPV) versus EZ form brace as an additional therapyin patients with discopathy and leg pain. Our hypothesis is that the OPVwill result in greater pain relief and increased self-reported functionalitythan the EZ.STUDY DESIGN/SETTING: Prospective randomized clinical trial withfollow-up at 6, 12, 26, and 52 weeks.PATIENT SAMPLE: Patients (93) with back pain failing 4 weeks ofconservative care, confirmed discopathy, and radiating leg pain were solic-ited. Inclusion required ability to stand upright and have consistent relieflying down. Candidates (87) were initially evaluated. A subgroup (25)did not enter therapy because of intervening clinical improvement, traveldistance or change in interest. Sixty-two were participants.OUTCOME MEASURES: Self-reported VAS and Oswestry (Osw) scoreswere primary outcomes.METHODS: Consenting patients received an OPV or EZ based on aprospective randomization scheme under separate security. Assessment wasby independent evaluator at 6, 12, 26 and 52 weeks. Once randomized, thepatient saw the principal investigator (PI), blind to assessment and outcomes,for fitting. Analysis was by repeated measures ANOVA. A secondaryanalysis of change scores between the initial and 52-week outcome was byunpaired t test. A logit model was created to define patient characteristicsof successful outcome defined as improvement �25% in VAS.