5:18 158. Junctional kyphosis in patients following surgical treatment for Scheuermann's kyphosis: What are the risk factors?

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prognostic criteria for the two cohorts were as similar as possible. The preoperative BMD scores, T-scores of the hip (specifically, fem neck), and WHO classifications were then compared to determine if there was a significant difference between the two groups, which would help determine whether low BMD scores are predictive of fixation failure following spinal reconstruction. RESULTS: 36 patients were identified in the failure cohort. The success cohort 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. 33 Caucasian/ 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 magnitude (61.0 v. 61.1⬚), and fusion to the pelvis (17 vs. 17 cases). The mean fem neck BMD score was 0.740 in the failure cohort and 0.767 in the success cohort. Mean fem neck T-score was –1.66 in the failure cohort and –1.40 in the “success” cohort. The mean fem neck WHO classification score was 2.03 (1-Normal, 2-Osteopenia, 3-Osteoporosis) in failure cohort and 1.91 in the success cohort. The mean total hip BMD score was 0.848 in the failure cohort and 0.847 in the success cohort. The mean total hip T-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 neck and total hip BMD testing between two matched cohorts with and without fixation failure. The results of this study suggest that the utility of preoperative BMD testing with DEXA in predicting fixation failure in patients with adult scoliosis undergoing spinal reconstruction may be limited. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.159

5:12 157. Spinal cord level pedicle subtraction osteotomy for the treatment of thoracic kyphosis: early results and complications Stephen Lewis, MD, Manoj Singrakhia, Y. Raja Rampersaud, FRCS(C), MD; University of Toronto, Toronto, Ontario, Canada BACKGROUND CONTEXT: Severe thoracic kyphosis presents a technically difficult challenge to spinal surgeons. Surgical options include anterior lengthening procedures, multiple Smith Petersen osteotomies, or pedicle subtraction osteotomies. The rigidness of the deformity and chest wall makes correction of these deformities difficult. The technique of thoracic level pedicle subtraction osteotomies has not been well described in the literature. PURPOSE: To determine the early results and safety of patients undergoing spinal cord level (SCL) pedicle subtraction osteotomy (PSO) for the treatment of thoracic kyphosis. STUDY DESIGN/SETTING: Retrospective case series. PATIENT SAMPLE: 23 consecutive patients undergoing single or multiple spinal cord level osteotomies for the treatment of fixed thoracic kyhosis. OUTCOME MEASURES: Outcomes measured include the the radiographic correction, the early peri-operative complications, and intra-operative data. METHODS: Radiographic and chart review of correction and perioperative complications of 23 consecutive patients undergoing spinal cord level pedicle subtraction ostetomies. RESULTS: The underlying diagnoses were: tumor (8), Scheuermann’s Kyphosis (4), degenerative/osteoporosis (3), fracture (3), inflammatory (2), congenital kyphosis (1), tuberculosis (1), and infected tumor (1). The osteotomy was combined with a lumbar PSO in five patients. Three patients were treated with double thoracic osteotomies. Two PSOs were extended transdiscally to debride the infected disc. The mean focal PSO correction was 27.2⬚ (range 2–77⬚). The overall thoracic kyphosis measured from T5 to T12 improved from a mean of 53.8⬚ preoperatively to 38.5⬚ postoperatively. Estimated blood loss ranged from 400cc to 13000cc. All patients presenting with preoperative spinal cord dysfunction improved neurologically postoperatively. There was 1 major neurological complication. One patient developed postoperative progressive paraplegia following a prolonged period

of intra- and postoperative severe hypotension and coagulopathy. Other complications included: Pleural tears (3), deep wound infection (1), transient T3 radicular pain (1); dural tears (2); myocardial infarction (1); Atrial fibrillation (1); fractures proximal to the thoracic (2) and distal to lumbar (3) instrumentation; incomplete corrections of severe sagittal malalignment despite double osteotomies (2); wound breakdown due to preoperative radiation (1). CONCLUSIONS: Spinal cord level PSO is a feasible option for severe thoracic kyphosis. This procedure eliminates the need for anterior surgery. A higher complication rate was noted in patients requiring multiple osteotomies for severe deformities, and inflammatory deformities stopped short of the sacrum. All tumor patients presenting with incomplete spinal cord lesions gained improvement in their neurological function. A high patient satisfaction was noted. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.160

5:18 158. Junctional kyphosis in patients following surgical treatment for Scheuermann’s kyphosis: What are the risk factors? Edward Sun, MD1, Francis Denis2, John Lonstein2; 1SpineCare Medical Group, Daly City, CA, USA; 2Twin Cities Spine Center, Minneapolis, MN, USA BACKGROUND CONTEXT: Previously reported risk factors for junctional kyphosis include inappropriate end vertebrae selection, curve correction ⬎50%, or excessive junctional soft tissue dissection. PURPOSE: To analyze the risk factors associated with proximal junctional kyphosis (PJK) and distal junctional kyphosis (DJK) in patients undergoing instrumented spinal fusion for Scheuermann’s kyphosis with different types of fixation constructs. STUDY DESIGN/SETTING: Retrospective review of consecutive patients undergoing instrumented fusion for Scheuermann’s kyphosis. PATIENT SAMPLE: Clinical and radiographic data on 67 patients were reviewed. All patients had complete radiographic data with minimum 5 year follow-up (mean 73 months). OUTCOME MEASURES: Radiographic measurement of proximal and distal junctional kyphosis in preoperative radiograph and most recent clinical follow-up. METHODS: Proximal junctional angle is defined as the Cobb measurement between the cranial end plate of the upper instrumented vertebra to the cranial end plate two vertebrae above. Abnormal PJK was defined by proximal junctional angle ⬎10 degrees and at least 10 degrees greater than the corresponding preoperative measurement. Distal junctional kyphosis is similarly defined between the caudal end plate of the lower instrumented vertebra to the caudal end plate one vertebra below. Fifteen patients (22%) with flexible curves (hyperextension ⬍50 degrees) were treated with posterior only while others (78%) were treated with combined anterior and posterior procedures. Due to the difficulty visualizing the upper thoracic vertebrae on some standing long cassette radiographs, a novel method with previously confirmed intra- and inter-observer reliability was used to select the proximal end vertebra. This method relies on identification of the anterior and posterior cortex in the visualized portion of lower cervical and upper thoracic vertebral bodies, drawing a “best fit line” between these points, and using the perpendicular to the “best fit line” to estimate the proximal end vertebra. RESULTS: Incidence of PJK as defined is seen in 20 patients (30%). The development of PJK is associated with failure to incorporate the proximal end vertebra (15 patients), disruption of junctional ligamentum flavum (3 patients), or combination (2 patients). The ligamentum flavum disruption was due to the use of supralaminar hooks in 2 patients and sublaminar wire in one patient. The development of PJK does not appear to be associated with initial magnitude of the curve or the amount of correction achieved (range 20–68%). The most common cause of inappropriate end vertebra selection

Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S was poor visualization of upper thoracic vertebra and this error can be minimized 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. Fifteen patients required additional surgery for instrumentation removal (9), repair of pseudoarthrosis (1), infection (1), and repair of symptomatic DJK (5). CONCLUSIONS: Minimum 5 year follow-up of patients who underwent surgical treatment for Scheuermann’s kyphosis revealed high incidence of PJK although the majority are asymptomatic. The incidence of PJK can be minimized by the appropriate selection of upper end vertebra and avoiding disruption of junctional ligamentum flavum. The development of DJK can be minimized by incorporation of the 1st lordotic disc into the fusion construct. 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

5:24 159. Favorable outcome in the treatment of high grade L5S1 spondylolytic spondylolisthesis with autogenous fibular strut grafting Michael 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 stabilization of a high grade (Meyerding Grade 3 or greater) spondylolytic spondylolisthesis is not always attainable or safe. Placement of a fibular graft from the sacrum to the 5th lumbar vertebra with partial reduction of the spondylolisthesis 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 spondylolytic spondylolisthesis have high complication rates and poor outcomes. We report 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’s goal is to demonstrate safety and reduction in pain with this method at two institutions. STUDY DESIGN/SETTING: A cohort of consecutive patients presenting with high grade L5/S1 spondylolytic spondylolisthesis was treated with fibular strut grafting, posterior instrumentation and partial reduction at two institutions. PATIENT SAMPLE: Thirteen patients, 10 female and 3 male were treated. OUTCOME MEASURES: Clinical outcome was evaluated by improvement in visual analogue pain score (VAS), Oswestry score, and radiographic assessments of fusion. METHODS: Patients were evaluated preoperatively and postoperatively at 6 weeks, 3 months, 6 months and annually. VAS and Oswestry scores were recorded at each assessment to measures changes in pain, serial radiographs performed to assess sagittal alignment and fusion of the fibular graft. RESULTS: Mean follow-up was 31.53 months (12–69 months). The mean age was 31 years old (range 12–64) All patients had posterior pedicle screw instrumentation and decompression of the L5 nerve roots. Mean number of levels fused was 3. All patients had autogenous fibular grafting, 10 patients were treated by a posterior graft from the sacrum to L5, and 3 were treated by anterior placement from L5 to the sacrum. All cases but one were primary surgeries. The mean preoperative VAS was 9.19/10 (7.510/10), 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 one Meyerding Grade of reduction, the slip angle improved in all cases by a mean of 12 degrees. There were no failures of the fibular struts. There were no infections. Mean blood loss was 1634 cc (450 -5800 cc). There were no fibular donor site complications. Overall, there were 4 complications: three L5 nerve root palsies (2 cases completely resolved, a revision case experi-

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enced a permanent but, painless L5 palsy), and one case of asymptomatic S1 screw breakage. CONCLUSIONS: Autogenous fibular strut grafting for high grade spondylolytic spondylolisthesis is a useful surgical technique to facilitate fusion at the lumbosacral junction, when combined with posterior instrumentation. This technique has demonstrated reproducibility and an excellent improvement in pain based on VAS and Oswestry score. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.162

5:30 160. Study on the outcome of posterolateral fusion vs. posterior lumbar interbody fusion for grade ‡T and ‡U spondylolytic spondylolisthesis Dike Ruan, He Qing, Ding Yu, Hou Lisheng; Navy General Hospital, Beijing, China BACKGROUND CONTEXT: PLIF is considered as a better method for management of spondylolisthesis; it will have a high bone fusion rate and good clinical outcome. PURPOSE: The present study evaluates the outcome of two methods for stabilization and fusion: posterolaterial fusion (PLF) and posterior lumbar interbody fusion (PLIF) for grade ‡Tand ‡U spondylolytic spondylolisthesis. STUDY DESIGN/SETTING: To compare the mean operative time, mean bleeding, clinical outcome based on JOA scoring system, low back pain, and bone union between PLF and PLIF groups. There were no differences in age, duration, clinical picture, and slippage between the PLF and PLIF groups. Laminectomy, decompression of spinal canal, and short segment pedicle fixation were conducted in all patients. PATIENT SAMPLE: Totally, there were 67 cases in the series, 32 cases in the posterolateral fusion group and 35 cases in the posterior lumbar interbody fusion group. OUTCOME MEASURES: The mean operative time, mean bleeding, clinical outcome based on JOA scoring system, low back pain, and bone union between PLF and PLIF groups were compared. METHODS: The follow-up period was 2–10 years; the average was 5.8 and 4.5 years in the PLF and PLIF groups, respectively. The mean operative time, mean bleeding, clinical outcome based on JOA scoring system, low back pain, and bone union between PLF and PLIF groups were compared. RESULTS: Mean operative time was 187 min in the PLF group and 248 min in the PLIF group. Mean bleeding was 680 ml in the PLF group and 945 ml in the PLIF group. There was no significant difference of clinical outcome based on JOA scoring system between PLF and PLIF groups, but low 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 significant in both groups (p⬍.05), but the loss of correction at the last followup assessment was better in the PLIF group (p⬍.05). There were 19 and 11 complications in the PLF and PLIF groups, respectively. CONCLUSIONS: PLF and PLIF are both efficacious surgical procedures for low grade spondylolytic spondylolisthesis. Compared with the PLF procedure, the PLIF procedure had the disadvantages of longer operative time and more tissue trauma. On the other hand, the advantages of PLIF procedure 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 this indication. FDA device/drug: CD. Status: Approved for this indication. FDA device/drug: Tenor. Status: Approved for this indication. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.163