Mitsuru Yagi

Incidence, risk factors, and natural course of proximal junctional kyphosis: surgical outcomes review of adult idiopathic scoliosis. Minimum 5 years of follow-up.

Study Design. A retrospective case series of surgically treated patients with adult scoliosis. Objective. The purpose of this study was to evaluate the incidence, risk factors, and natural course of proximal junctional kyphosis (PJK) in a long-term follow-up of patients with adult idiopathic scoliosis undergoing long instrumented spinal fusion. Summary of Background Data. Although recent reports have showed the prevalence, clinical outcomes, and the possible risk factors of PJK, quite a few reports have showed long-term follow-up outcome. Materials and Methods. This is a retrospective review of the charts and radiographs of 76 consecutive patients with adult scoliosis treated with long instrumented spinal fusion. Radiographical measurements and demographic data were reviewed on preoperation, immediate postoperation, 2 years postoperation, 5 years postoperation, and at follow-up. Postoperative Scoliosis Research Society scores and Oswestry Disability Index were also evaluated. Means were compared with Student t test. A P value of less than 0.05 with 95% confidence interval was considered significant. Results. The mean age was 48.8 years (range, 23–75 yr) and the average follow-up was 7.3 years (range, 5–14 yr). PJK has been identified in 17 patients. The Scoliosis Research Society and Oswestry Disability Index did not demonstrate significant differences between PJK group and non-PJK group; 2 patients had additional surgeries performed for local pain. Seventy-six percent of PJK has been identified within 3 months after surgery. Despite the fact that 53% of total degree of PJK was progressed within 3 months after surgery, PJK continuously progressed to the final follow-up. Pre-existing low bone mineral density, posterior spinal fusion (PSF), fusion to sacrum, inappropriate global spine alignment, and greater sagittal vertical axis change were identified as significant risk factors for PJK (P = 0.04, P < 0.001, P = 0.02, P < 0.0001, and P = 0.01). Conclusion. In a long-term review of minimum 5 years, 76% of PJK occurred within 3 months after surgery. Pre-existing low bone mineral density, PSF, fusion to the sacrum, inappropriate global spine alignment, and greater sagittal vertical axis change were significant risk factors for PJK. Careful long-term follow-up should be done for a patient with PJK.

Combined Anterior-Posterior Surgery is the Most Important Risk Factor for Developing Proximal Junctional Kyphosis in Idiopathic Scoliosis

BackgroundSeveral studies have identified risk factors for proximal junctional kyphosis (PJK) after instrumentation for scoliosis, but the relative risks are unclear.Questions/purposesWe identified risk factors for PJK in idiopathic scoliosis and determined their relative risks in a predictive model.MethodsWe retrospectively reviewed the charts of all 249 patients with idiopathic scoliosis who underwent surgery from 1996 to 2008. We compared those who developed PJK to those who did not. We identified risk factors for PJK and performed univariate and multivariate analyses to determine independent risk factors. We then used a Cox proportional-hazards model to evaluate the time to the development of PJK. The minimum followup time was 1.5xa0years (mean, 4xa0years; range, 1.5–9xa0years).ResultsThe incidence of PJK in our series of patients with idiopathic scoliosis was 17%. There was no difference in Scoliosis Research Society-22 scores between patients without and with junctional kyphosis. Independent risk factors included proximal fusion to T1 through T3 and sagittal sacral vertical line, while in the Cox model a combined anterior-posterior approach surgery was the most important risk factor.ConclusionsPatients with a T1 through T3 upper instrumented level, combined anterior-posterior surgery, and increased sagittal sacral vertical line difference had a higher likelihood of developing PJK. Of these risk factors, anterior-posterior surgery was the strongest risk factor.Level of Evidence Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Does the intraoperative tranexamic acid decrease operative blood loss during posterior spinal fusion for treatment of adolescent idiopathic scoliosis

Study Design. Retrospective, observational study. Objective. To assess the efficacy and safety of tranexamic acid (TXA) in decreasing operative blood loss and the need for transfusion during posterior spinal fusion for the treatment of idiopathic scoliosis in adolescents. Summary of Background Data. Blood loss associated with spinal surgery is a common potential cause of morbidity and often requires a blood transfusion, which subjects patients to the known risks of blood transfusion including transmission of diseases. Since the 1990s, intraoperative administration of antifibrinolytics has gained popularity. This study assesses the efficacy and safety of TXA in controlling blood loss during posterior spinal fusion for the treatment of idiopathic scoliosis in adolescents at 1 institution. Methods. A retrospective comparative analysis of 106 consecutive adolescents undergoing posterior spinal fusion procedures at 1 institution was performed. Patients were analyzed according to treatment group: controls (63) and TXA (43). There were no significant differences in demographic (age, sex, and comorbidities) or surgical traits (surgical time, number of fused vertebrae, preoperative hematocrit and hemoglobin) between the 2 groups. Results. TXA group had significantly less intraoperative blood loss (613 ± 195 mL) than the control group (1079 ± 421 mL; P < 0.001) as well as postoperative blood loss (155 ± 86 mL and 263 ± 105 mL, respectively; P < 0.001). TXA group received significantly less blood during the surgical procedure than the control group (258 ± 246 mL and 377 ± 200 mL, respectively; P < 0.001). There were no major intraoperative complications for any of the treatment groups. Conclusion. TXA treatment group lost significantly less blood and received significantly fewer blood transfusions than the control group without significant differences in intra- and postoperative complications. A multicenter randomized prospective analysis would provide additional information of the efficacy and safety of TXA.

Complications and Unfavorable Clinical Outcomes in Obese and Overweight Patients Treated for Adult Lumbar or Thoracolumbar Scoliosis With Combined Anterior/Posterior Surgery.

Background Context: Combined anterior/posterior (A/P) spinal fusion with instrumentation has been used for many years in the treatment of adult thoracolumbar and lumbar (TL/L) scoliosis. However, the risk factors for complications and poor clinical outcomes with this procedure are not well known. Purpose: To assess the risk factors for poor clinical outcomes in a series of adult lumbar or scoliosis patients undergoing combined A/P-instrumented spinal fusion. Study Design: This study was a retrospective case series of surgically treated adult lumbar or thoracolumbar scoliosis patients. Patient Sample: From 1998 to 2006, 57 patients with diagnoses of adult idiopathic scoliosis or degenerative TL/L scoliosis underwent combined A/P spinal instrumentation and fusion at 1 institution, performed by 1 senior author. Outcome Measurements: The preoperative and postoperative outcome measurements included self-report measurements, physiological measurements, and functional measurements. Materials and Methods: A retrospective review of this patient group was performed to evaluate patient satisfaction, functional outcomes, pain, curve progression, and complications. Radiographic measurements included coronal balance, sagittal vertical axis, Cobb angle, thoracic kyphosis, lumbar lordosis, and pelvic incidence preoperatively, immediately postoperatively, and during follow-up. In terms of risk factors, bone mineral density, body mass index, age, kyphosis, and fusion to the sacrum were reviewed. Postoperative Scoliosis Research Society Patient Questionnaire outcome scores, Oswestry Disability Index (ODI), and anterior surgical site pain (ASSP) were also evaluated. Means were compared with the Student t test and the &khgr;2 test. Logistic regression analyses were used to predict the probabilities and the odds ratios (ORs) of the risk factors for poor clinical outcomes. A P-value of <0.05 with a confidence interval of 95% was considered significant. Results: Fifty patients had adult idiopathic scoliosis, and 7 patients had degenerative scoliosis. The average age at surgery was 53.8 years (34–74 y), and the average follow-up was 4.8 years (2–11 y). Coronal correction for thoracic, thoracolumbar, and lumbosacral curves improved significantly. The degree of sagittal curve and coronal and sagittal balance were not significantly changed after surgery or at the final follow-up. ODI, the pain intensity domain of the ODI, and ASSP were significantly worse in obese and overweight patients, whereas OR time, estimated blood loss, and number of fused vertebrae were not different in the entire group (P=0.03 for ODI, P=0.002 for pain domain of ODI, and P=0.003 for ASSP). Logistic regression analyses for the risk factors of poor clinical outcomes indicated obesity and overweight as risk factors for poor clinical outcomes (OR=6.25 for ODI and 5.88 for ODI pain intensity score). A significantly higher rate of major complications occurred in this group compared to the entire group (30.4%, P=0.04). Low bone mineral density, old age, kyphosis, and fusion to the sacrum were not risk factors for poor clinical outcomes. Conclusions: Despite the good function scores and acceptable pain levels in most patients, the ODI scores of obese and overweight patients were worse compared to the rest of the patients in this study. Significantly worse scores on the pain intensity domain of the ODI and ASSP differences were likely caused by extensive dissection of the abdominal wall and psoas muscles and the technical difficulty of achieving an anterior approach to the thoracolumbar spine. Radiographs revealed no progression of the TL/L curves. This study indicates that obesity and overweight are potential risk factors for combined A/P-instrumented spinal fusion in patients with adult TL/L scoliosis, perhaps due to the technical difficulty of achieving an anterior approach to the thoracolumbar spine.

Long-term Clinical and Radiographic Outcomes of Pedicle Subtraction Osteotomy for Fixed Sagittal Imbalance: Does Level of Proximal Fusion Affect the Outcome? Minimum 5-Year Follow-up

STUDY DESIGNnRetrospective case series of surgically treated adult patients with fixed sagittal imbalance.nnnOBJECTIVEnTo assess clinical and radiographic changes after pedicle subtraction osteotomy (PSO) to treat adult fixed sagittal imbalance.nnnBACKGROUNDnAlthough recent reports have shown favorable clinical outcomes for PSO, few reports have published long-term follow-up outcomes. It is also unknown whether long-term outcomes are correlated with the level of proximal fusion and the radiographic changes that are observed after PSO.nnnMATERIALS AND METHODSnWe reviewed the charts, X-rays, and postoperative SRS-22 and Oswestry Disability Index (ODI) scores of 32 adult patients who presented with fixed sagittal imbalance and were treated with lumbar PSO. Long fusions were defined as those proximal to T6, and short fusions were defined as those below T8. Measured radiographic parameters included thoracic kyphosis, lumbar lordosis (LL), sacral slope, pelvic incidence, and sagittal balance (SVA). Statistical analysis included Student t test and chi-square test. A p value of < .05 and a confidence interval of 95% were considered statistically significant.nnnRESULTSnAmong the reviewed cases were 23 women and 9 men, with a mean age of 50.9 years (range, 33-76 years) and a mean follow-up 8.6 years (range, 5-16 years). The LL increased from -16.0° preoperatively to -52.1° postoperatively. This metric decreased to -51.0° at final follow-up. The SVA decreased from 10.4 cm preoperatively to 3.6 cm postoperatively. The SVA increased to 5.4 cm at the final follow-up visit. There were 17 long fusions and 15 short fusions. The SRS scores at the final follow-up time point were: total, 3.63; function, 3.59; pain, 3.68; self-image, 3.46; mental health, 3.56; satisfaction, 4.26. A total of 16 patients exhibited minimal disability, 11 exhibited moderate disability, and 2 exhibited severe disability in ODI scores at the final follow-up visit (average, 28.2%). The SRS and ODI scores were not significantly different between groups (p = .64 for SRS; p = .59 for ODI). We observed no significant differences between groups with respect to the LL, sacral slope, or pelvic incidence. The observed increase in SVA at the final follow-up visit was significantly larger in the short fusion group compared with the increase we observed in the long fusion group (p = .03). The thoracic kyphosis (T5-T12) and proximal junctional angle at the final follow-up visit also significantly increased in patients who underwent a short fusion (p < .001). A total of 14 major complications occurred in 12 patients (8 in the short fusion group and 6 in the long fusion group) (p = .43). Eight patients required additional surgery to treat these complications.nnnCONCLUSIONSnIn a group of adults presenting with fixed sagittal imbalance, PSO provided good sagittal balance and maintained favorable clinical outcomes in both the short and long fusion groups despite a slight decrease in the SVA and a high complication rate. The data suggest that the loss of sagittal balance may be attributed to increase global and junctional kyphosis in short fusion groups, and should be monitored for long-term outcomes. Particular attention should be paid to the long-term deterioration of the SVA in adults who present with fixed sagittal imbalance after PSO.

Chest cage angle difference and rotation of main thoracic curve are independent risk factors of postoperative shoulder imbalance in surgically treated patients with adolescent idiopathic scoliosis.

Study Design. Retrospective case series of surgically treated adolescent patients with scoliosis. Objective. To assess the prevalence and independent risk factors for postoperative shoulder imbalance in surgically treated adolescent patients with idiopathic scoliosis. Summary of Background Data. Despite recent reports that have identified risk factors for postoperative shoulder imbalance, the relative risks remain unclear. Methods. A retrospective review of 85 consecutive patients treated with thoracic fusion with a minimum 2-year follow-up (mean, 3.1 yr) was conducted to investigate the patient radiographical measurements and demographics. Shoulder height difference (SHD) was measured as the graded height difference of the soft tissue shadows. A SHD more than 2 cm indicated an unbalanced shoulder. Patient demographics and radiographical data were studied to determine risk factors for postoperative SHD. The potential risk factors included age, sex, Risser sign, Cobb angle, flexibility, and apical vertebral rotation (AVR) of the main curve, upper-instrumented vertebra level, SHD, and clavicle chest cage angle difference (CCAD). Univariate and multivariate logistic regression analyses were performed to determine the independent risk factors for postoperative shoulder imbalance. Results. Of the 85 patients, 21 patients presented postoperative shoulder imbalance. The univariate analysis indicated age, Risser sign, Cobb angle of the main curve, AVR of the main curve, and CCAD as risk factors, but the multivariate logistic regression analysis showed that only AVR of the main curve and CCAD were independent risk factors for postoperative shoulder imbalance (AVR, P = 0.04, odds ratio (OR): 3.54; CCAD, P = 0.01, OR: 5.10). Conclusion. Postoperative shoulder imbalance was observed in 25% of the surgically treated adolescent patients. The CCAD and AVR of the main thoracic curve were independent risk factors for postoperative shoulder imbalance in surgically treated patients with adolescent idiopathic scoliosis. The significant correlation between CCAD and postoperative shoulder imbalance seen in this study strongly suggests that the relationship of the shoulder girdle and chest cage has a role in maintaining shoulder balance. Level of Evidence: 4

Clavicle chest cage angle difference (CCAD): a novel predictor of postoperative shoulder imbalance in patients with adolescent idiopathic scoliosis.

Study Design. Retrospective case series of surgically treated patients with adolescent scoliosis. Objective. To establish a new radiographical measurement method to determine the best preoperative predictor of postoperative shoulder balance. Summary of Background Data. Shoulder balance is an important aspect of the overall cosmetic balance in patients with adolescent idiopathic scoliosis. Despite recent reports, it is still difficult to estimate the postoperative shoulder balance accurately. Methods. A retrospective review of 89 consecutive patients who had thoracic fusion with a minimum 2-year follow-up (mean, 3.1 yr) was conducted to investigate the radiographical measurements and patient demographics. The shoulder height difference (SHD) was measured as the graded height difference of the soft tissue shadows. SHD more than 2 cm indicated an unbalanced shoulder. The clavicle chest cage angle difference (CCAD) was established and evaluated. The CCAD was graded as grade A: no imbalance (<0°), grade B: mild imbalance (0°–10°), and grade C: significant imbalance (>10°). Results. Of the 89 patients, 22 patients had a moderate or significant SHD at 2 years postoperatively and were categorized as the unbalanced shoulder group (unbalanced SD). A significant difference was observed in preoperative CCAD between the balanced and unbalanced SD groups (P = 0.01). The intraclass correlation coefficient for CCAD was 0.94 among the observers. CCAD was consistent from the preoperative to the final postoperative follow-ups in both groups. The classification of the CCAD preoperatively indicated that 12 of 22 (54.4%) patients who were classified into the postoperative unbalanced SD group showed grade 3 CCAD preoperatively, whereas only 9 of 67 (13.4%) patients who were classified in the postoperative balanced SD group had grade 3 CCAD preoperatively. Conclusion. The developed method to predict postoperative shoulder balance was demonstrated to be easy to perform, reliable, and practical. Additionally, we classified the estimation of postoperative shoulder imbalance by preoperation CCAD. The results of this comprehensive review will guide spinal surgeons in their preoperative planning and in the surgical management of adolescent idiopathic scoliosis to reduce postoperative shoulder imbalance. Level of Evidence: 4

Adult thoracolumbar and lumbar scoliosis treated with long vertebral fusion to the sacropelvis: a comparison between new hybrid selective spinal fusion versus anterior-posterior spinal instrumentation

BACKGROUND CONTEXTnCombined anteroposterior spinal fusion with instrumentation has been used for many years to treat adult thoracolumbar/lumbar scoliosis. This surgery remains a technical challenge to spine surgeons, and current literature reports high complication rates.nnnPURPOSEnThe purpose of this study is to validate a new hybrid technique (a combination of single-rod anterior instrumentation and a shorter posterior instrumentation to the sacrum) to treat adult thoracolumbar/lumbar scoliosis.nnnSTUDY DESIGNnThis study is a retrospective consecutive case series of surgically treated patients with adult lumbar or thoracolumbar scoliosis.nnnPATIENT SAMPLEnThis is a retrospective study of 33 matched pairs of patients with adult scoliosis who underwent two different surgical procedures: a new hybrid technique versus a third-generation anteroposterior spinal fusion.nnnOUTCOME MEASURESnPreoperative and postoperative outcome measures include self-report measures, physiological measures, and functional measures.nnnMETHODSnIn a retrospective case-control study, 33 patients treated with the hybrid technique were matched with 33 patients treated with traditional anteroposterior fusion based on preoperative radiographic parameters. Mean follow-up in the hybrid group was 5.3 years (range, 2-11 years), compared with 4.6 years (range, 2-10 years) in the control group. Operating room (OR) time, estimated blood loss, and levels fused were collected as surrogates for surgical morbidity. Radiographic parameters were collected preoperatively, postoperatively, and at final follow-up. The Scoliosis Research Society Patient Questionnaire (SRS-22r) and Oswestry Disability Index (ODI) scores were collected for clinical outcomes.nnnRESULTSnOperating room time, EBL, and levels fused were significantly less in the hybrid group compared with the control group (p<.0001). The postoperative thoracic Cobb angle was similar between the hybrid and control techniques (p=.24); however, the hybrid technique showed significant improvement in the thoracolumbar/lumbar curves (p=.004) and the lumbosacral fractional curve (p<.0001). The major complication rate was less in the hybrid group compared with the control group (18% vs. 39%, p=.01). Clinical outcomes at final follow-up were not significantly different based on overall SRS-22r scores and ODI scores.nnnCONCLUSIONnThe new hybrid technique demonstrates good long-term results, with less morbidity and fewer complications than traditional anteroposterior surgery select patients with thoracolumbar/lumbar scoliosis. This study received no funding. No potential conflict of interest-associated bias existed.

Outcome of Revision Surgery in Pediatric Spine Deformity Patients

STUDY DESIGNnRetrospective case series.nnnOBJECTIVESnTo report the complications and outcomes of pediatric revision spine surgery and review the surgical indications and treatment methods.nnnBACKGROUND SUMMARYnRecent reports have shown the necessity of revision spine surgery for pediatric deformities. Many reports have shown the result of revision surgery for pediatric spinal deformity.nnnMATERIALS AND METHODSnWe conducted a retrospective review of 638 patients with pediatric spinal deformity who were treated with surgery from 1996 to 2007. We identified 50 patients who underwent revision spinal fusion surgery with a minimum of 3 years of follow-up.nnnRESULTSnMean follow-up was 4 years (range, 3-8.3 years). The diagnosis at index surgery was idiopathic scoliosis in 18 patients, congenital scoliosis in 13, neuromuscular scoliosis in 13, tumor and spinal arteriovenous malformation in 4, burst fracture in thoracic spine in 1, and Scheuermann kyphosis in 1. The primary surgeries were 1 hemi epiphysiodesis, 3 anterior spinal fusions, 4 posterior decompressions, 8 combined anterior and posterior spinal fusions, and 34 posterior spinal fusions. A total of 16 patients had pseudarthrosis, 12 decompensation, 11 progressive kyphosis, 8 crankshaft phenomenon, 2 infections, and 1 junctional degeneration. All 50 reoperations included spinal instrumentation and fusion. The revision surgeries were 2 anterior spinal fusions, 14 posterior fusions, and 34 combined anterior and posterior spinal fusions. Spine arthrodesis was obtained in 98% of patients (49 of 50) and complications occurred in 14% of patients (7 of 50). The Scoliosis Research Society Patient Questionnaire outcomes at the latest follow-up were as follows: total 3.95, function 3.88, pain 3.83, self-image 3.98, and mental health 4.04.nnnCONCLUSIONnPseudarthrosis was the most common indication for revision surgery, and bony union was achieved in 98% with revision surgery. Despite the complications, pediatric revision spine surgery can achieve successful outcomes.