Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S98S

P64. The sagittal alignment of the spine and pelvis in the presenceof L5-S1 isthmic lysis and low-grade spondylolisthesisSohrab Gollogly1, Pierre Roussouly2, Eric Berthonnaud3, JohnesDimnet4, Hubert Labelle5; 1University of Utah, Salt Lake City, UT,USA; 2Centre des Massues, Lyon, France; 3Lyon, France; 4Group ofApplied Orthopedic Research, Lyon, France; 5Sainte-Justine Hospital,Montreal University, Montreal, Quebec, Canada

BACKGROUND CONTEXT: The etiology of spondylolisthesis is multi-factorial. Sagittal alignment of the spine is thought to play a role in pathogen-esis. This study measured the sagittal alignment of the spine in 82 patientswith L5-S1 spondylolysis and �50% displacement. The cohort was selectedin order to document the native alignment of the spine prior to the develop-ment of a large deformity secondary to progression. The cohort was com-pared to a control population of 160 patients without symptoms of backpain or radiographic abnormalities of the spine and pelvis.PURPOSE: To measure and document the global sagittal alignment ofthe spine and pelvis in patients with low grade spondylolisthesis.STUDY DESIGN/SETTING: A retrospective review of all patients pres-enting to two medical centers for consultation for back pain or deformitywho were subseauently diagnosed with spondylolisthesis.PATIENT SAMPLE: 82 patients met the diagnostic criteria of a radiologi-cally obvious L5—S1 spondylolisthesis with less than 50% displacement.OUTCOME MEASURES: No outcome measures were used in this study.METHODS: A retrospective review of the full-length radiographs of 82patients (range 4 to 74 years, avg 19) with low grade spondylolysiswas performed (�grade II / 50% displacement). The % displacement ofL5 on S1 and was graded according to the system of Meyerding. Theamount of segmental lordosis between L4/L5 and L5/S1 was calculated.The global sagittal alignment of the spine and lumbo-pelvic area wasmeasured using a technique of computerized analysis that has been pre-viously described. Correlations between the geometric parameters of spinaland pelvic alignment were determined using the Pearson correlation coeffi-cient. The comparision of the values was done with a student’s T test.RESULTS: In this study, the majority of patients with spondylolysis andlow-grade spondylolisthesis have increased pelvic incidence, a more verti-cally oriented L5-S1 intervertebral disk, and less segmental extension be-tween L5 and S1 than normal patients. A second group of patients has apelvic incidence of �45� (n�10), a low grade sacral slope, and a longthoracic kyphosis. This disposition suggests localized hyperextension be-tween L5 and S1 creates mechanical impingement upon the posteriorelements.CONCLUSIONS: These data should further an appreciation of the seeingspondylolysis and spondylolisthesis in the context of the global alignmentof the spine and pelvis as producing two different etiologies.DISCLOSURES: Device or drug: Optimage (TM) radiology softwareapplication. Status: Investigational/Not approved.

Table 1The geometric parameters describing sagittal alignment for normalsand the cohort with spondylolysis and spondylolisthesis.

Average inParameters Normal spondy Min Max

Spondylolisthesis 0% 30.85% 1.01 49.7Pelvic incidence 51.91� 64.66* 37.90 85.64Sacral slope 39.92� 49.65 31.84 65.97Pelvis tilt 11.99� 15.01 �6.55 42.69L5 incidence 21.43� 29.83* 7.44 79.75L5-Sl extension �12.79� �8.79* �31.88 38.12Thoracic kyphosis 47.67� 41.39 9.7 79.6# vertebrae 12.25� 4.0 8.5 13.0Inflection point 4.50� T10 T4 L1Lumbar lordosis 61.43 57.45* 24.7 91.8# lordotic vertebrae 4.5 3.87 1.50 10.00Age 26 19.31 4.0 74

CONFLICT OF INTEREST: Author (SG) Consultant: Author acknowl-edges a financial relationship (Consultant, Medtronic) which may indirectlyrelate to the subject of this abstract.

doi: 10.1016/j.spinee.2004.05.199

P109. The effect of heating on the biomechanical properties of theintervertebral disc tissue in a porcine modelJeffrey Wang, MD1, Nick Shamie, MD2, J. Kabo, PhD1, Lee Halevi,BS1; 1University of California, Los Angeles, Los Angeles, CA, USA;2University of California, Los Angeles, Santa Monica, CA, USA

BACKGROUND CONTEXT: The use of heat treatments, like IDET, onintervertebral discs is controversial, however, the effect of heat treatmenton the biomechanical properties of intervertebral disc tissue has not beenstudied.PURPOSE: The purpose of this study was to examine the effects of heatingon the biomechanical properties of intervertebral disc tissues using a well-controlled, porcine model.STUDY DESIGN/SETTING: In a laboratory setting, porcine functionalspinal units containing adjacent vertebral bodies, including the disc, wereharvested. In addition, calf tendons were also harvested from the samespecimen.PATIENT SAMPLE: Ten porcine lumbar spines and twenty-five calftendons (Achilles tendons) were harvested and utilized as the subjects forthis study.OUTCOME MEASURES: The effects of the heat treatments were studiedusing measures such as disc shrinkage, histological studies, and with biome-chanical strength testing to determine whether there were any effects ofthe treatments. The tendons were also subjected to the same heat treatments tounderstand the effectsofheat treatmentson soft tissue tendons and to compareto the results of the disc treatments.METHODS: The vertebral body-disc-vertebral body segments were coredto a uniform size for testing to assure a consistent size between eachspecimen. The calf tendons were also cut to uniforms lengths for testing.Five specimens were utilized for each group. Each group was heated bysubmersion in a water bath at the defined temperature to assure uniformheating throughout each specimen. The specimens were divided into groupsand heated at temperatures of 60�C, 65�C, 70�C, or 75�C for 10 minutes. Theeffects were assessed by measuring the actual shrinkage, histological stain-ing with hematoxylin and eosin (H&E), and biomechanical testing tofailure using mechanical loading on an MTS servohydraulic testing machineoperating under stroke control. Non heated controls were used forcomparisons.RESULTS: The porcine tendons had no measurable shrinkage in specimensheated below 65�C. At temperatures above 65�C all of the shrinkagewas concluded within two minutes of immersion and it appeared that70�C was the optimal temperature, as temperatures higher than this didnot demonstrate noticeable effects. The disc samples were heated to 70�C(optimum temperature) and there appeared to be contraction of the tissue, butno measurable shrinkage could be appreciated. Histologically, the specimensdemonstrated individual fibrous collagen striations that lost their distinctionas the temperature increased. In the tendons, at 75�C all of the fibers appearto be fused with distinct striations no longer present. Biomechanical testingrevealed that the tendons undergo a substantial reduction in stiffness whenheated. The mean tendon stiffness for the unheated specimens was 19,356psi while the corresponding value for the heated tendons was 1,023 psi.These were significantly different using the paired t-test at p�0.0043. Forthe disc samples, there was no significant difference in either stiffness(p�0.182) or failure strength (p�0.998). All failures occurred in mid-substance of the disk tissue.CONCLUSIONS: The application of uniform heating to intervertebraldiscs does appear to cause some contraction of the collagen, however, there isno detectable biomechanical effect in terms of stiffness or ultimate failurestrength of the functional spinal unit. Based on the results of this por-cine model, there does not appear to be a beneficial biomechanical effectof the use of heat treatments to the intervertebral disc.

Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S 99S

DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No Conflicts.

doi: 10.1016/j.spinee.2004.05.201

DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No Conflicts.

doi: 10.1016/j.spinee.2004.05.200

P14. Middle and longterm follow up outcomes of laminoplasty forpatients with ossification of the posterior longitudinal ligament ofcervical spineAkihito Wada1, Hiroshi Takahashi2, Yukikazu Okajima2, Toru Suguro2;1TOHO University, Cordova, TN, USA; 2TOHO University School ofMedicine, Japan

BACKGROUND CONTEXT: Laminoplasty is a therapeutic procedureperformed for multilevel cervical myelopathy due to ossification of the pos-terior longitudinal ligament (OPLL) and cervical spondylotic myelopathy(CSM). However, several authors shown that surgical outcomes of lami-noplasty performed for patients with OPLL were less successful thanCSM cases.PURPOSE: The objective of this study is to determine the factors affectingthe middle and long-term outcomes of laminoplasty for the treatment ofpatients with OPLL.STUDY DESIGN/SETTING: A matched cohort clinical and radiographicretrospective analysis of laminoplasty for the treatment of patients withOPLL and compared them to patients with CSM.PATIENT SAMPLE: Medical records of 147 patients treated for OPLLand CSM with spinous process splitting laminoplasty between 1985 and1998 at our institution were reviewed. Twenty-six (17 males, 9 females)patients with OPLL that underwent laminoplasty were matched with 26(15 males, 11 females) patients with CSM. Ossification type at the timeof surgery was continuous in 8, segmental in 5, mixed type in 13 patientsin case of OPLL based on radiographic findings. Mean follow-up durationwas 124.1 months for OPLL cases and 110.2 months for CSM cases.OUTCOME MEASURES: For statistic analysis, an unpaired Student’st-test was used.METHODS: Severity of myelopathy was evaluated according to the Japa-nese Orthopedic Association (JOA) score of cervical myelopathy. In caseof OPLL, development of ossification was evaluated by postoperative radio-graphic finding with (1) more than 3 mm development of vertical length,(2) more than 2 mm development of axial thickness, (3) convert segmentalor mixed type into continuous type, and (4) newly formation of OPLL atanother level including thoracic and lumbar spine. Clinical and radiographicassessments were performed preoperatively, one year after surgery, and atthe latest follow-up, respectively.RESULTS: Cohorts were well matched based on patient age (OPLL:53.5yrs. CSM: 54.5yrs.), duration of symptoms (OPLL: 23.8mo. CSM:22.9mo.), and JOA score (OPLL: 10.8 points. CSM: 9.8 points.) beforesurgery. The mean JOA scores in OPLL cases were 10.8 points before sur-gery, improved to 14.7 points after one year, but worsened to 13.8 pointsat the latest follow-up. Whereas the scores in CSM cases were 9.8points before surgery, improved to 14.2 points after one year, and maintained14.1 points at the latest follow-up. Development of OPLL was observed in 15(57.7%) cases at the time of latest follow-up. The mean age at the time ofsurgery on those patients were younger than non-development cases (51.8yrs. vs. 59.8 yrs.), and of them 11 cases of mixed type ossification beforesurgery were developed to be continuous type at latest follow-up. Im-provement in JOA scores at latest follow-up was 2.2 points in developmentof OPLL cases and 4.0 points in non-development cases. Causation of re-aggravation in JOA scores was detectable in 4 cases with development ofOPLL cases. Newly formation of OPLL at thoracic spine was observed in3 obese, age less than 45 years old female cases. Development of thicknessof OPLL at decompressed level was observed in 1 male case.CONCLUSIONS: Middle and long term outcome of laminoplasty in pa-tients with OPLL was less satisfactory than patients with CSM. Age less than45 years old female with obese case in patients with cervical myelopathydue to OPLL should also perform thoracic laminoplasty at the time offirst surgery.

P59. The vertebral compression fracture pain and functionaldisability questionnaire: a new instrument for the assessment ofback pain and disabilityAvery J. Evans, MD1, Kevin E. Kip, PhD2, Selene M. Boutin, ARNP1;1Tampa Bay Radiology Consultants, PL, Tampa, FL, USA; 2Universityof Pittsburgh, PA, USA

BACKGROUND CONTEXT: A limitation of the ability to compare theeffectiveness of different therapies in the treatment of vertebral compressionfractures (VCF) is the lack of standard instrumentation designed specificallyto measure pain and functional status both before and after treatment.PURPOSE: We have devised a questionnaire specific to the assessment ofpain and disability associated with VCF, and now report on its psychometricproperties among 72 patients recently treated with percutaneous polymeth-ylmetacrylate vertebroplasty (PPV).STUDY DESIGN/SETTING: Through literature review and meetingamong PPV surgeons and data management specialists, a pilot instrumentwas developed to collect information on patients with vertebral fracturesbeing treated with PPV (Evans et al. 2003). Lessons learned from the initialpilot study were: (i) minimize the length of time for patient recall and datacollection; (ii) expand the list of ADLs; and (iii) include a separate, validatedinstrument for comparison.PATIENT SAMPLE: 72 patients.OUTCOME MEASURES: The internal consistency reliability of the 24ADL items was estimated by the coefficient alpha. In addition, Spearmanrank correlation coefficients were calculated between scores on each ADLand the average ADL score among all ADLs performed.METHODS: The initial pilot instrument has been revised to include anexpanded list of ADLs, and has been appended with the Oswestry LowBack Pain Questionnaire (Fairbank et al, 1980). The first section of theBaseline questionnaire contains a total of 11 items that address the patient’sprior and current magnitude of back pain and distress. Three “pain” items aremeasured using a visual analog scale. Two additional pain items are mea-sured using an adjectival scale. Two “distress” items are measured usingeither a visual analog scale ranging or an adjectival scale. The remaining fouritems are measured using either a 5-point Likert scale or dichotomous yes/no responses. The second section of the Baseline questionnaire lists 24activities of daily living (ADLs), measured on a 5-point scale ranging from1 (absolutely unable to do because of pain) to 5 (able to do without pain).RESULTS: At the baseline administration, internal consistency reliabilityestimates for the ADL items ranged from 0.89 to 0.94. Rank correlationsbetween individual ADL scores and the average score among all ADLs per-formed were similar among the baseline and follow-up administrations,and were generally high, ranging from 0.55 to 0.97. At the baseline admin-istration, rank correlations between the average score of all ADLs performedand questionnaire measures of pain and distress ranged from 0.29 to 0.51.The corresponding correlation between the average scores of all ADLsperformed and all Oswestry dimensions was 0.65.CONCLUSIONS: The Vertebral Compression Fracture Pain and func-tional Disability Questionnaire is a useful and reliable instrument specific tothe assessment of back pain and disability associated with VCFs.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No Conflicts.

doi: 10.1016/j.spinee.2004.05.202

P54. Lumbar pseudarthrosis model in athymic ratsSeth Gamradt, MD, Wellington Hsu, MD, Tom Mroz, MD, Mario Luna,BS, Patrick Suen, MD, Nick Shamie, MD, Jay Lieberman, Jeffrey C.Wang, MD; University of California, Los Angeles, Los Angeles, CA,USA