Christine Baldus

Complications and Outcomes of Pedicle Subtraction Osteotomies for Fixed Sagittal Imbalance

Study Design. Radiographic analysis, outcomes analysis (pain scale, Oswestry, SRS-24), and accumulation of complications. Outcomes and complications collected prospectively. Radiographic analysis performed retrospectively. Objectives. To assess the benefits and stress complications of pedicle subtractions osteotomies for patients with fixed sagittal imbalance. Summary of Background Data. Few reports on pedicle subtraction osteotomies exist in the peer-review literature for conditions other than trauma and ankylosing spondylitis. Materials and Methods. Thirty-three consecutive patients with sagittal imbalance treated with lumbar pedicle subtraction osteotomy at one institution (minimum 2-year follow-up) were analyzed. Complications were also analyzed for the entire group of consecutive pedicle subtraction osteotomies done at our institution to date (n = 66). Results. For the 33 patients with minimum 2-year follow-up, there were significant improvements in the overall Oswestry score (P 0.0001) and pain score (P = 0.0001). Most patients reported improvement in pain and self-image and reported overall satisfaction based on ultimate SRS-24 questionnaire. There was one pseudarthrosis in the lumbar spine through an area of pedicle subtraction osteotomy (area of previous laminectomy and nonunion), and six patients had thoracic pseudarthroses (levels other than the osteotomy level) and one patient had a pseudarthrosis at L5-S1. Two patients had acute angular kyphosis at the thoracolumbar junction at the proximal end of the construct. Five patients who experienced transient neurologic deficits resolved their deficits after central canal enlargement. Conclusions. The clinical result with pedicle subtraction osteotomy is reduced with pseudarthrosis in the thoracic or lumbar spine and subsequent breakdown adjacent to the fusion. For patients with a degenerative sagittal imbalance etiology the results were worse and the complications were higher. Central canal enlargement is critical.

Results of lumbar pedicle subtraction osteotomies for fixed sagittal imbalance: a minimum 5-year follow-up study.

Study Design. Retrospective study. Objective. To report results at a minimum 5 years after pedicle subtraction osteotomy for fixed sagittal imbalance. Summary of Background Data. No one has reported results of pedicle subtraction osteotomies with a 5- to 8-year follow-up. Method. Thirty-five consecutive patients with sagittal imbalance (29 females/6 males, average age at surgery, 53.1 years) treated with lumbar pedicle subtraction osteotomies (1 at L1, 13 at L2, 20 at L3, and 1 at L4) at 1 institution were analyzed (average follow-up, 5.8 years; range, 5–7.6 years). Radiographic and clinical outcomes analysis was performed. Results. There were no significant regional radiographic changes between 2 years postoperative and the ultimate follow-up (proximal junctional change, P = 0.30; thoracic kyphosis, P = 0.38; and lumbar lordosis, P = 0.84), although many patients did demonstrate an increasingly anterior C7 sagittal plumb with time. Ten pseudarthroses (29%) occurred in 8 patients and were revised between 2 and 5 years postoperative. There were no pseudarthroses at the osteotomy level (9 at the thoracolumbar junction, 1 at the LS junction), but at the levels added to the previous fusions. There was no degradation in Oswestry and Scoliosis Research Society (SRS) outcome scores between 2 years postoperative and ultimate follow-up (P = 0.23 and 0.90, respectively). Patients reported very good satisfaction (87%), good self-image (76%), good function (69%), and fair pain subscales (66%) at ultimate follow-up. Sagittal vertical axis <8 cm at ultimate follow-up was significant for better SRS outcomes scores (P = 0.038). Eight patients with revised pseudarthroses did not demonstrate poorer SRS outcomes scores (P = 0.52). Those 8 patients were queried after their pseudarthrosis revision surgery. Conclusion. Pedicle subtraction osteotomy can provide satisfactory clinical and radiographic outcomes for patients with a minimum 5-year follow-up despite needing pseudarthrosis revision and some component of increasingly positive sagittal vertical axis between 2 years and 5 to 8 years of follow-up. The level of patient satisfaction and self-image subscales were high after more than 5 years of follow-up. Restoration and maintenance of sagittal vertical axis <8 cm were important to the ultimate sagittal reconstruction.

Minimum 5-year analysis of L5-S1 fusion using sacropelvic fixation (bilateral S1 and iliac screws) for spinal deformity.

Study Design. Clinical radiographic and outcomes investigation. Objective. To investigate clinical and radiographic outcomes for lumbosacral fusion (in patients with spinal deformity) using a combination of bilateral sacral and iliac screws with a minimum 5-year follow-up. Summary of Background Data. To our knowledge, long-term results (>5 years of follow-up) of bilateral S1 screw/bilateral iliac screw fixation have never been published or presented. Materials and Methods. A total of 67 patients (from an initial consecutive cohort of 81) undergoing lumbosacral fusion with bilateral sacral and iliac screws with a minimum follow-up of 5 years (range 5–10 + 5, average 6 + 3) were analyzed for radiographic outcome and clinical course by an outcome questionnaire (administered at ultimate follow-up) analysis. Patients were divided into 2 groups: group 1, 34 patients with mostly high-grade spondylolisthesis; and group 2, 33 with adult scoliosis fused mostly from the thoracic spine to the sacrum. A true anteroposterior pelvis film was obtained in all patients to assess for sacroiliac joint arthritis, as were standard spine radiographs. Patients were administered Oswestry and directed buttock pain questionnaires at latest follow-up. Results. There were no cases of sacral screw failure (i.e., screw loosening, partial screw pullout, or fracture of the sacral screw). There were 5 cases of nonunion at L5–S1. Of the 5 cases, 3 did not have anterior column support at L5–S1. Four of the 5 cases were revised, and, subsequently, 3 achieved union. Iliac screws were removed electively on 1 or both sides in 23 of the patients after 2 years postoperatively because of prominence. There were 7 cases of iliac screw breakage. Iliac screw halos were observed in 29 patients. No sacroiliac osteoarthritis was observed on the true anteroposterior pelvis films. At ultimate follow-up, average visual analog painscale (0–10) score to assess buttock pain was 2.4, and average Oswestry score was 20.1. Conclusions. For high-grade spondylolisthesis and long adult deformity fusions to the sacrum, a montage of bilateral S1 screws and iliac screws were effective in protecting the sacral screws from failure. Pseudarthrosis at L5–S1 was manifested by rod breakage at that level. We saw no evidence of a long-term effect of the iliac screws predisposing the sacroiliac joints to degeneration at follow-up ranging from 5 to 10 years.

Does Treatment (Nonoperative and Operative) Improve the Two-Year Quality of Life in Patients With Adult Symptomatic Lumbar Scoliosis: A Prospective Multicenter Evidence-Based Medicine Study

Study Design. Prospective observational cohort study with matched and unmatched comparisons. Level II evidence. Objective. The purpose of this study is to compare results of adult symptomatic lumbar scoliosis (ASLS) patients treated nonoperatively and operatively. This is an evidence-based prospective multicenter study to answer the question of whether nonoperative and operative treatment improves the quality of life (QOL) in these patients at 2-year follow-up. Summary of Background Data. Only 1 paper in the peer-reviewed published data directly addresses this question. That paper suggested that operative treatment was more beneficial than nonoperative care, but the limitations relate to historical context (all patients treated with Harrington implants) and the absence of validated patient-reported QOL (QOL) data. Methods. This study assesses 160 consecutively enrolled patients (ages 40–80 years) with baseline and 2-year follow-up data from 5 centers. Lumbar scoliosis without prior surgical treatment was defined as a minimum Cobb angle of 30° (mean: 54° for patients in this study). All patients had either an Oswestry Disability Index (ODI) score of 20 or more (mean: 33) or Scoliosis Research Society (SRS) domain scores of 4 or less in pain, function, and self-image (mean: 3.2) at baseline. Pretreatment and 2-year follow-up data collected prospectively included basic radiographic parameters, complications and SRS QOL, ODI, and Numerical Rating Scale back and leg pain scores. Results. At 2 years, follow-up on the operative patients was 95% and for the nonoperative patients it was 45%.The demographics for the nonoperative patients who were followed up for 2 years versus those who were lost to follow-up were identical. The operative cohort significantly improved in all QOL measures. The nonoperativecohort did not improve and nonsignificant decline in QOL scores was common. At minimum 2-year follow-up, operative patients outperformed nonoperative patients by all measures. Conclusion. It would appear from this study that common nonoperative treatments do not change the QOL in patients with ASLS at 2-year follow-up. However, operative treatment does significantly improve the QOL for this group of patients. Our conclusions are limited by the fact that we were only able to follow-up 45% of the nonoperative group to 2-year follow-up, in spite of extensive efforts on our part to accomplish such.

The validity of the SRS-22 instrument in an adult spinal deformity population compared with the Oswestry and SF-12: a study of response distribution, concurrent validity, internal consistency, and reliability.

Study Design. Prospective analysis of a consecutive cohort of adult spinal deformity patients queried over a 12-month period. Objectives. To assess the SRS-22 instrument compared with the SF-12 and Oswestry. Summary of Background Data. Very few reports in the literature have applied the SRS-22 to adult spinal deformity patients. Methods. Consecutive adult spinal deformity patients were applied the SRS-22, SF-12, and Oswestry. Four analyses were done: 1) floor/ceiling effect; 2) Pearson’s correlation coefficients between the SRS-22, SF-12, and Oswestry; 3) Cronbach’s alpha analysis for internal consistency within the SRS-22; and 4) test/retest. Results. Floor/ceiling range for the SRS-22 compared favorably with the SF-12 and Oswestry. The Pearson’s coefficients correlating the two questionnaires relative to the SRS-22 were > 0.7. The Cronbach’s alpha within each domain for the SRS-22 were > 0.7, except for pain (0.67). Test/retest correlation coefficients ranged from 0.84 to 0.95 for the subscales. Conclusions. The SRS-22 is a disease-specific instrument with the capacity to demonstrate change in health status more effectively than the SF-12 and in more domains than the Oswestry. The SRS-22 showed high criterion validity with the SF-12 and Oswestry based on Pearson’s coefficients. High Cronbach’s alpha scores suggested a high internal consistency within each domain of the SRS-22, except for pain (0.67). Test/retest reliability was excellent.

Major complications in revision adult deformity surgery: Risk factors and clinical outcomes with 2- to 7-year follow-up

Study Design. Retrospective cohort comparative study. Objective. To determine the prevalence of major complications, identify risk factors, and assess long-term clinical benefit after revision adult spinal deformity surgery. Summary of Background Data. No study has analyzed risk factors for major complications in long revision fusion surgery and whether or not occurrence of a major complication affects ultimate clinical outcome. Methods. Analysis of consecutive adult patients who underwent multilevel revision surgery for spinal deformity with a minimum 2-year follow-up was performed. All complications were classified as either major or minor. Outcome analysis was conducted with the Scoliosis Research Society and Oswestry Disability Index scores. Results. A total of 166 patients (mean age = 53.8 years) were identified with a mean follow-up of 3.5 years (range: 2–7). Primary diagnoses included idiopathic/de novo scoliosis (107), degenerative (35), trauma (7), neuromuscular scoliosis (6), congenital deformity (5), ankylosing spondylitis (2), tumor (2), Scheuermann kyphosis (1), and rheumatoid arthritis (1). Most common secondary diagnoses that necessitated revision surgery were adjacent segment disease, fixed sagittal imbalance, and pseudarthrosis. Overall, 34.3% of patients developed major complications (19.3% perioperative; 18.7% follow-up). Associated risk factors for perioperative complications were patient- (age > 60 years, medical comorbidities, obesity) and surgery-related (pedicle subtraction osteotomy). Performance of a 3-column osteotomy and postoperative radiographic changes that suggested progressive loss of sagittal correction were recognized as risk factors for follow-up complications. Equivalent outcome scores were reported by patients preoperatively, but those experiencing follow-up complications reported lower scores at the final follow-up. Conclusion. Overall, 34.4% of patients experienced major complications after long revision fusion surgery. Different risk factors were identified for perioperative versus follow-up complications. The occurrence of a follow-up, not but perioperative, major complication seemed to have a negative impact on ultimate clinical outcome.

Is the SRS-22 instrument responsive to change in adult scoliosis patients having primary spinal deformity surgery?

Study Design. Multicenter study. Objective. The purpose of this study is to prospectively analyze responsiveness of the SRS-22 to change at 1 and 2 years following primary surgery. Summary of Background Data. A number of efforts have been directed at validation of the SRS-22 instrument in the setting of adolescent and adult spinal deformity. However, few have extensively analyzed the ability of the instrument to detect change (brought on by surgical treatment) in adult scoliosis patients. Methods. A multicenter prospective series of consecutive adult scoliosis patients (all primary/no revisions) were administered SRS-22, Oswestry Disability Index (ODI)and Short Form-12 (SF-12) questionnaires preoperation and 1 and 2 years postoperation. Fifty-six patients had preoperative, 1-year postoperative, and 2-year postoperative data. Results. The greatest changes from preoperation to 2-year postoperation were the SRS self-image domain followed by SRS total, SRS pain, and ODI scores. SRS pain and function scores significantly (P < 0.05) improved from 1-year to 2-year postoperation. There were not substantial differences in the outcome measures according to age or curve type. All outcome measures except SF-12 mental health showed statistically significant (P < 0.05) improvement from baseline to 2-year follow-up. Conclusion. Based on these 3 outcome tools, the greatest responsiveness to change was demonstrated by the SRS self-image domain followed by SRS total, then SRS pain, then ODI. This suggests that the SRS tool is more responsive than ODI, which is more responsive than SF-12 to change brought on by primary surgical treatment of adult scoliosis patients. Surgical treatment in adult scoliosis significantly improved pain, self-image, and function based on the health-related quality of life measures used in this study.

Changes in Radiographic and Clinical Outcomes With Primary Treatment Adult Spinal Deformity Surgeries From Two Years to Three- to Five-Years Follow-up

Study Design. Retrospective analysis of data entered prospectively into a multicenter database—clinical and radiographic outcomes assessment. Objective. Our hypothesis is that between the 2-year and the 3- to 5-year points surgically treated adult spinal deformity patients will show significant reduction in outcomes by Scoliosis Research Society (SRS), Oswestry Disability Index (ODI), and numerical rating scale back and leg pain scores and will show increasing thoracic kyphosis, loss of lumbar lordosis, and loss of coronal and sagittal balance. Summary of Background Data. Most analyses of primary presentation adult spinal deformity surgery assess 2-year follow-up. However, it is established that in some patients unfavorable events occur between the 2-year and 5-year points. Methods. The cohort of 113 patients entered into a multicenter database with complete preoperative, 2-year, and 3- to 5-year data. All patients who had adult spinal deformity and surgical treatment represented their first reconstruction. Diagnoses were scoliosis (82.5%), kyphosis (10%), and scoliosis and kyphosis combined (7.5%). Outcome measures and basic radiographic parameters (curve size, thoracic and lumbar sagittal plane, coronal and sagittal balance) were assessed at those 3 time intervals. Complications (pseudarthrosis/implant failure, infection, and junctional deformities) were assessed at the 2-year and the 3- to 5-year (mean, 3.76 years) points. Results. The mean major curve Cobb angle (preoperative, 57°; 2-year, 29°; 3–5 year, 26°); thoracic kyphosis T5 to T12 (30°, 31°, 32°) and lumbar lordosis T12 to sacrum (48°, 49°, 51°) did not change from the 2-year to ultimate follow-up. Likewise, coronal and sagittal balance parameters were the same at 2-year and ultimate follow-up. SRS total scores and modified ODI were similar at the 2 year and final follow-up (SRS: 3.89–3.88; ODI: 19–18). Preoperative SRS total score was 3.17. Six patients demonstrated complications at the 2-year point and additional 9patients demonstrated complications at the 3- to 5-year point. Those 9 patients with complications at ultimate follow-up demonstrated significant deterioration in their ODI and SRS scores when compared with the patients who did not have complications at ultimate follow-up. Conclusion. Contrary to our hypothesis, we could not establish deterioration in mean radiographic or clinical outcomes between the 2-year and 3- to 5-year follow-up points when analyzing the group as a whole. However, for the 9 patients who experienced complications between 3- and 5-year follow-up, their outcomes were significantly worse than for the other 104 patients. One should not anticipate an overall radiographic and clinical deterioration of the outcomes of surgically treated primary presentation adult spinal deformity patients in this studied time interval. However, close to 10% of patients will experience a new complication at the 3- to 5-year point, most commonly implant failure/nonunion and/or junctional kyphosis, which will negatively effect the patient-reported outcome.

Does a long-fusion "t3-Sacrum" portend a worse outcome than a short-fusion "t10-Sacrum" in primary surgery for adult scoliosis?

Study Design. Retrospective clinicoradiographic analysis. Objective. To compare the upper thoracic (UT) and lower thoracic (LT) spines as the upper instrumented vertebra in primary fusions to the sacrum for adult scoliosis. Summary of Background Data. The optimal level at which a fusion to the sacrum is terminated proximally for adult scoliosis remains controversial. We hypothesized that (1) UT spine would have an increased pseudarthrosis, more perioperative complications, and worse outcomes and (2) LT spine would have more proximal junctional kyphosis. Methods. Patients who underwent primary surgery for adult scoliosis between 2002 and 2006 were studied. UT and LT groups were matched cohorts. Minimum follow-up for all patients was 2 years. Scoliosis Research Society scores and Oswestry Disability Index were the clinical outcome measures. Results. Fifty-eight patients (UT = 20, LT = 38) with a mean age of 55.7 years were followed for an average of 3.0 ± 1.1 years. The UT group had greater preoperative thoracic kyphosis and coronal Cobb values (P < 0.05). Diagnoses were idiopathic scoliosis (75.9%) and degenerative scoliosis (24.1%). The UT cohort had a greater number of levels fused (15.8 vs. 8.6) and higher blood loss (1350 mL vs. 811 mL). Operative time, recombinant human bone morphogenetic protein-2 per level, and caudal interbody grafting (80.0% UT vs. 89.5% LT) were similar. The UT group experienced an increased number of perioperative complications (30.0% vs. 15.8%), more pseudarthrosis (20.0% vs. 5.3%), and a higher prevalence of revision surgery (20.0% vs. 10.5%). The LT group had more proximal junctional kyphosis (18.4% vs. 10.0%). Scoliosis Research Society scores and Oswestry Disability Index were improved in both cohorts in all domains (P < 0.001), except function (P = 0.07) and mental health (P = 0.27), which were not significantly improved in the UT group. Conclusion. With long fusions to the sacrum, one should anticipate more perioperative complications, a higher pseudarthrosis rate, and perhaps more revision surgery than short fusions. Short fusions may result in a more proximal junctional kyphosis, only rarely requiring revision surgery.

Proximal Junctional Kyphosis in Primary Adult Deformity Surgery: Evaluation of 20 Degrees as a Critical Angle

BACKGROUND : Multiple studies have reported on the prevalence of proximal junctional kyphosis (PJK) following spinal deformity surgery; however, none have demonstrated its significance with respect to functional outcome scores or revision surgery. OBJECTIVE : To evaluate if 20° is a possible critical PJK angle in primary adult scoliosis surgery patients as a threshold for worse patient-reported outcomes. METHODS : Clinical and radiographic data of 90 consecutive primary surgical patients at a single institution (2002-2007) with adult idiopathic/degenerative scoliosis and 2-year minimum follow-up were analyzed. Assessment included radiographic measurements, but most notably sagittal Cobb angle of the proximal junctional angle at preoperation, between 1 and 2 months, 2 years, and ultimate follow-up. RESULTS : Prevalence of PJK ≥20° at 3.5 years was 27.8% (n = 25). Those with PJK ≥20° at ultimate follow-up were older (mean 56 vs 46 years), had lower number of levels fused (median 8 vs 11), and were proximally fused to the lower thoracic spine more often than upper thoracic spine (all P < .001). PJK ≥20° was associated with significantly higher body mass index and fusion to the sacrum with iliac screws (P < .016, P < .029, respectively). Scoliosis Research Society outcome score changes were lower for PJK patients, but not significantly different from those in the non-PJK group. CONCLUSION : PJK ≥20° in primary adult idiopathic/degenerative scoliosis does not lead to revision surgery for PJK, but is univariately associated with older age, shorter constructs starting in the lower thoracic spine, obesity, and fusion to the sacrum. The negative results, supported by Scoliosis Research Society outcome data, provide important guidance on the postoperative management of such PJK patients. ABBREVIATIONS : BMI, body mass indexLIV, lowest instrumented vertebraeODI, Oswestry Disability IndexPJ, proximal junctionalPJK, proximal junctional kyphosisSRS, Scoliosis Research SocietyUIV, upper instrumented vertebra.