Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S82S

prognostic criteria for the two cohorts were as similar as possible. The preop-erative BMD scores, T-scores of the hip (specifically, fem neck), and WHOclassifications were then compared to determine if there was a significantdifference between the two groups, which would help determine whetherlow BMD scores are predictive of fixation failure following spinalreconstruction.RESULTS: 36 patients were identified in the failure cohort. The successcohort of 36 patients was matched to the failure cohort (failure v. success)by age (64�1 v. 63�3y), gender (32 v. 32 females), race (32 v. 33Caucasian/ Asian), anterior fusion levels (5.8 v. 6.0), posterior fusion levels(11.5 v. 10.8), total fusion levels (16.6 v. 15.8), preoperative curve magni-tude (61.0 v. 61.1�), and fusion to the pelvis (17 vs. 17 cases). The meanfem neck BMD score was 0.740 in the failure cohort and 0.767 in thesuccess cohort. Mean fem neck T-score was –1.66 in the failure cohortand –1.40 in the “success” cohort. The mean fem neck WHO classificationscore was 2.03 (1-Normal, 2-Osteopenia, 3-Osteoporosis) in failure cohortand 1.91 in the success cohort. The mean total hip BMD score was 0.848in the failure cohort and 0.847 in the success cohort. The mean total hipT-score was –1.06. in the failure cohort and –1.10 in the success cohort.No values reached statistical significance.CONCLUSIONS: There was no significant difference in femoral neckand total hip BMD testing between two matched cohorts with and withoutfixation failure. The results of this study suggest that the utility of preopera-tive BMD testing with DEXA in predicting fixation failure in patients withadult scoliosis undergoing spinal reconstruction may be limited.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.159

5:12157. Spinal cord level pedicle subtraction osteotomy for thetreatment of thoracic kyphosis: early results and complicationsStephen Lewis, MD, Manoj Singrakhia, Y. Raja Rampersaud, FRCS(C),MD; University of Toronto, Toronto, Ontario, Canada

BACKGROUND CONTEXT: Severe thoracic kyphosis presents a techni-cally difficult challenge to spinal surgeons. Surgical options include anteriorlengthening procedures, multiple Smith Petersen osteotomies, or pediclesubtraction osteotomies. The rigidness of the deformity and chest wallmakes correction of these deformities difficult. The technique of thoraciclevel pedicle subtraction osteotomies has not been well described in theliterature.PURPOSE: To determine the early results and safety of patients undergoingspinal cord level (SCL) pedicle subtraction osteotomy (PSO) for the treat-ment of thoracic kyphosis.STUDY DESIGN/SETTING: Retrospective case series.PATIENT SAMPLE: 23 consecutive patients undergoing single or multi-ple spinal cord level osteotomies for the treatment of fixed thoracic kyhosis.OUTCOME MEASURES: Outcomes measured include the the radiographiccorrection, the early peri-operative complications, and intra-operative data.METHODS: Radiographic and chart review of correction and peri-operative complications of 23 consecutive patients undergoing spinal cordlevel pedicle subtraction ostetomies.RESULTS: The underlying diagnoses were: tumor (8), Scheuermann’sKyphosis (4), degenerative/osteoporosis (3), fracture (3), inflammatory (2),congenital kyphosis (1), tuberculosis (1), and infected tumor (1). The osteot-omy was combined with a lumbar PSO in five patients. Three patientswere treated with double thoracic osteotomies. Two PSOs were extendedtransdiscally to debride the infected disc. The mean focal PSO correctionwas 27.2� (range 2–77�). The overall thoracic kyphosis measured from T5 toT12 improved from a mean of 53.8� preoperatively to 38.5� postoperatively.Estimated blood loss ranged from 400cc to 13000cc. All patients presentingwith preoperative spinal cord dysfunction improved neurologically postop-eratively. There was 1 major neurological complication. One patient devel-oped postoperative progressive paraplegia following a prolonged period

of intra- and postoperative severe hypotension and coagulopathy. Othercomplications included: Pleural tears (3), deep wound infection (1), transientT3 radicular pain (1); dural tears (2); myocardial infarction (1); Atrialfibrillation (1); fractures proximal to the thoracic (2) and distal to lumbar(3) instrumentation; incomplete corrections of severe sagittal malalignmentdespite double osteotomies (2); wound breakdown due to preoperativeradiation (1).CONCLUSIONS: Spinal cord level PSO is a feasible option for severethoracic kyphosis. This procedure eliminates the need for anterior surgery.A higher complication rate was noted in patients requiring multiple osteoto-mies for severe deformities, and inflammatory deformities stopped shortof the sacrum. All tumor patients presenting with incomplete spinal cordlesions gained improvement in their neurological function. A high patientsatisfaction was noted.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.160

5:18158. Junctional kyphosis in patients following surgical treatmentfor Scheuermann’s kyphosis: What are the risk factors?Edward Sun, MD1, Francis Denis2, John Lonstein2; 1SpineCare MedicalGroup, Daly City, CA, USA; 2Twin Cities Spine Center, Minneapolis,MN, USA

BACKGROUND CONTEXT: Previously reported risk factors for junc-tional kyphosis include inappropriate end vertebrae selection, curve cor-rection �50%, or excessive junctional soft tissue dissection.PURPOSE: To analyze the risk factors associated with proximal junctionalkyphosis (PJK) and distal junctional kyphosis (DJK) in patients undergoinginstrumented spinal fusion for Scheuermann’s kyphosis with different typesof fixation constructs.STUDY DESIGN/SETTING: Retrospective review of consecutive pa-tients undergoing instrumented fusion for Scheuermann’s kyphosis.PATIENT SAMPLE: Clinical and radiographic data on 67 patients werereviewed. All patients had complete radiographic data with minimum 5year follow-up (mean 73 months).OUTCOME MEASURES: Radiographic measurement of proximal anddistal junctional kyphosis in preoperative radiograph and most recent clini-cal follow-up.METHODS: Proximal junctional angle is defined as the Cobb measurementbetween the cranial end plate of the upper instrumented vertebra to thecranial end plate two vertebrae above. Abnormal PJK was defined byproximal junctional angle �10 degrees and at least 10 degrees greater thanthe corresponding preoperative measurement. Distal junctional kyphosis issimilarly defined between the caudal end plate of the lower instrumentedvertebra to the caudal end plate one vertebra below. Fifteen patients (22%)with flexible curves (hyperextension �50 degrees) were treated with poste-rior only while others (78%) were treated with combined anterior andposterior procedures. Due to the difficulty visualizing the upper thoracicvertebrae on some standing long cassette radiographs, a novel method withpreviously confirmed intra- and inter-observer reliability was used to selectthe proximal end vertebra. This method relies on identification of theanterior and posterior cortex in the visualized portion of lower cervical andupper thoracic vertebral bodies, drawing a “best fit line” between these points,and using the perpendicular to the “best fit line” to estimate the proximalend vertebra.RESULTS: Incidence of PJK as defined is seen in 20 patients (30%). Thedevelopment of PJK is associated with failure to incorporate the proximalend vertebra (15 patients), disruption of junctional ligamentum flavum (3patients), or combination (2 patients). The ligamentum flavum disruptionwas due to the use of supralaminar hooks in 2 patients and sublaminar wirein one patient. The development of PJK does not appear to be associated withinitial magnitude of the curve or the amount of correction achieved (range20–68%). The most common cause of inappropriate end vertebra selection

Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S 83S

enced a permanent but, painless L5 palsy), and one case of asymptomaticS1 screw breakage.CONCLUSIONS: Autogenous fibular strut grafting for high grade spondy-lolytic spondylolisthesis is a useful surgical technique to facilitate fusion atthe lumbosacral junction, when combined with posterior instrumentation.This technique has demonstrated reproducibility and an excellent improve-ment in pain based on VAS and Oswestry score.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.162

5:30160. Study on the outcome of posterolateral fusion vs. posterior

was poor visualization of upper thoracic vertebra and this error can beminimized by using the “best fit line” technique. DJK occurred in 8 patients(12%) and 7 of them had fusion short of the 1st lordotic disc. Fifteenpatients required additional surgery for instrumentation removal (9), repairof pseudoarthrosis (1), infection (1), and repair of symptomatic DJK (5).CONCLUSIONS: Minimum 5 year follow-up of patients who underwentsurgical treatment for Scheuermann’s kyphosis revealed high incidence ofPJK although the majority are asymptomatic. The incidence of PJK can beminimized by the appropriate selection of upper end vertebra and avoidingdisruption of junctional ligamentum flavum. The development of DJKcan be minimized by incorporation of the 1st lordotic disc into the fusionconstruct. Surgical repair was required in 63% of DJK cases.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.161

5:24159. Favorable outcome in the treatment of high grade L5S1spondylolytic spondylolisthesis with autogenous fibular strut graftingMichael Goytan, BSC, MD, FRCS(C)1, Jean Ouellet, MD, FRCS(C)2,Vincent Arlet, MD, FRCS(C)2; 1University of Manitoba, Winnipeg,Manitoba, Canada; 2McGill University, Montreal, Quebec, Canada

BACKGROUND CONTEXT: The complete reduction and stabilizationof a high grade (Meyerding Grade 3 or greater) spondylolytic spondylolisth-esis is not always attainable or safe. Placement of a fibular graft from thesacrum to the 5th lumbar vertebra with partial reduction of the spondylolisth-esis has been suggested as an effective, reproducible and safe treatment;however there are only 29 published cases.PURPOSE: Some described surgical methods to treat high grade spondylo-lytic spondylolisthesis have high complication rates and poor outcomes. Wereport the technique of an incomplete reduction of the spondylolisthesis,combined with fibular strut grafting and posterior instrumentation in L5/S1 spondylolytic spondylolisthesis (Meyerding 3 or greater). Our study’sgoal is to demonstrate safety and reduction in pain with this method attwo institutions.STUDY DESIGN/SETTING: A cohort of consecutive patients presentingwith high grade L5/S1 spondylolytic spondylolisthesis was treated withfibular strut grafting, posterior instrumentation and partial reduction attwo institutions.PATIENT SAMPLE: Thirteen patients, 10 female and 3 male were treated.OUTCOME MEASURES: Clinical outcome was evaluated by improve-ment in visual analogue pain score (VAS), Oswestry score, and radiographicassessments of fusion.METHODS: Patients were evaluated preoperatively and postoperativelyat 6 weeks, 3 months, 6 months and annually. VAS and Oswestry scoreswere recorded at each assessment to measures changes in pain, serialradiographs performed to assess sagittal alignment and fusion of the fibu-lar graft.RESULTS: Mean follow-up was 31.53 months (12–69 months). The meanage was 31 years old (range 12–64) All patients had posterior pedicle screwinstrumentation and decompression of the L5 nerve roots. Mean numberof levels fused was 3. All patients had autogenous fibular grafting, 10patients were treated by a posterior graft from the sacrum to L5, and 3were treated by anterior placement from L5 to the sacrum. All cases butone were primary surgeries. The mean preoperative VAS was 9.19/10 (7.5-10/10), and mean postoperative VAS was 2/10 (0-4/10) at last follow-up.Mean Oswestry scores were 32.31/50 preoperatively (16 -42/50) and 6.46/50 postoperatively (0 -16/50) at last follow-up. There was less than oneMeyerding Grade of reduction, the slip angle improved in all cases by amean of 12 degrees. There were no failures of the fibular struts. There wereno infections. Mean blood loss was 1634 cc (450 -5800 cc). There were nofibular donor site complications. Overall, there were 4 complications: threeL5 nerve root palsies (2 cases completely resolved, a revision case experi-

lumbar interbody fusion for grade ‡T and ‡U spondylolyticspondylolisthesisDike Ruan, He Qing, Ding Yu, Hou Lisheng; Navy General Hospital,Beijing, China

BACKGROUND CONTEXT: PLIF is considered as a better method formanagement of spondylolisthesis; it will have a high bone fusion rate andgood clinical outcome.PURPOSE: The present study evaluates the outcome of two methodsfor stabilization and fusion: posterolaterial fusion (PLF) and posterior lumbarinterbody fusion (PLIF) for grade ‡Tand ‡U spondylolytic spondylolisthesis.STUDY DESIGN/SETTING: To compare the mean operative time, meanbleeding, clinical outcome based on JOA scoring system, low back pain, andbone union between PLF and PLIF groups. There were no differences inage, duration, clinical picture, and slippage between the PLF and PLIFgroups. Laminectomy, decompression of spinal canal, and short segmentpedicle fixation were conducted in all patients.PATIENT SAMPLE: Totally, there were 67 cases in the series, 32 casesin the posterolateral fusion group and 35 cases in the posterior lumbarinterbody fusion group.OUTCOME MEASURES: The mean operative time, mean bleeding,clinical outcome based on JOA scoring system, low back pain, and boneunion between PLF and PLIF groups were compared.METHODS: The follow-up period was 2–10 years; the average was 5.8and 4.5 years in the PLF and PLIF groups, respectively. The mean operativetime, mean bleeding, clinical outcome based on JOA scoring system, lowback pain, and bone union between PLF and PLIF groups were compared.RESULTS: Mean operative time was 187 min in the PLF group and 248min in the PLIF group. Mean bleeding was 680 ml in the PLF group and945 ml in the PLIF group. There was no significant difference of clinicaloutcome based on JOA scoring system between PLF and PLIF groups, butlow back pain was improved 72.4% in PLF and 88.2% in PLIF (p�.042).Bone union was 74.8% in the PLF group and 94.3% in the PLIF group,respectively (p�.011). The correction of slippage was statistically signifi-cant in both groups (p�.05), but the loss of correction at the last follow-up assessment was better in the PLIF group (p�.05). There were 19 and11 complications in the PLF and PLIF groups, respectively.CONCLUSIONS: PLF and PLIF are both efficacious surgical proceduresfor low grade spondylolytic spondylolisthesis. Compared with the PLFprocedure, the PLIF procedure had the disadvantages of longer operativetime and more tissue trauma. On the other hand, the advantages of PLIFprocedure were a high rate of bone fusion, lower rate of implant failure,and more satisfactory improvement of low back pain.DISCLOSURES: FDA device/drug: Steffee. Status: Approved for thisindication. FDA device/drug: CD.Status: Approved for this indication. FDA device/drug: Tenor. Status: Ap-proved for this indication.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.163