Application of back-forward Bending CT localization image in the prediction of proximal junctional kyphosis after spinal deformity surgery in adults / 中国修复重建外科杂志

OBJECTIVE@#To investigate the feasibility of predicting proximal junctional kyphosis (PJK) in adults after spinal deformity surgery based on back-forward Bending CT localization images and related predictive indicators.@*METHODS@#A retrospective analysis was performed for 31 adult patients with spinal deformity who underwent posterior osteotomy and long-segment fusion fixation between March 2017 and March 2020. There were 5 males and 26 females with an average age of 62.5 years (range, 30-77 years). The upper instrumented vertebrae (UIV) located at T 5 in 1 case, T 6 in 1 case, T 9 in 13 cases, T 10 in 12 cases, and T 11 in 4 cases. The lowest instrumented vertebrae (LIV) located at L 1 in 3 cases, L 2 in 3 cases, L 3 in 10 cases, L 4 in 7 cases, L 5 in 5 cases, and S 1 in 3 cases. Based on the full-length lateral X-ray film of the spine in the standing position before and after operation and back-forward Bending CT localization images before operation, the sagittal sequence of the spine was obtained, and the relevant indexes were measured, including thoracic kyphosis (TK), lumbar lordosis (LL), local kyphosis Cobb angle (LKCA) [the difference between the different positions before operation (recovery value) was calculated], kyphosis flexibility, hyperextension sagittal vertical axis (hSVA), T 2-L 5 hyperextension C 7-vertebral sagittal offset (hC 7-VSO), and pre- and post-operative proximal junctional angle (PJA). At last follow-up, the patients were divided into PJK and non-PJK groups based on PJA to determine whether they had PJK. The gender, age, body mass index (BMI), number of fusion segments, number of cases with coronal plane deformity, bone mineral density (T value), UIV position, LIV position, operation time, intraoperative blood loss, osteotomy grading, and related imaging indicators were compared between the two groups. The hC 7-VSO of the vertebral body with significant differences between groups was taken, and the receiver operating characteristic curve (ROC) was used to evaluate its accuracy in predicting the occurrence of PJK.@*RESULTS@#All 31 patients were followed up 13-52 months, with an average of 30.0 months. The patient's PJA was 1.4°-29.0° at last follow-up, with an average of 10.4°; PJK occurred in 8 cases (25.8%). There was no significant difference in gender, age, BMI, number of fusion segments, number of cases with coronal plane deformity, bone mineral density (T value), UIV position, LIV position, operation time, intraoperative blood loss, and osteotomy grading between the two groups ( P>0.05). Imaging measurements showed that the LL recovery value and T 8-L 3 vertebral hC 7-VSO in the PJK group were significantly higher than those in the non-PJK group ( P>0.05). There was no significant difference in hyperextension TK, hyperextension LL, hyperextension LKCA, TK recovery value, LL recovery value, kyphosis flexibility, hSVA, and T 2-T 7, L 4, L 5 vertebral hC 7-VSO ( P>0.05). T 8-L 3 vertebral hC 7-VSO was analyzed for ROC curve, and combined with the area under curve and the comprehensive evaluation of sensitivity and specificity, the best predictive index was hC 7-L 2, the cut-off value was 2.54 cm, the sensitivity was 100%, and the specificity was 60.9%.@*CONCLUSION@#Preoperative back-forward Bending CT localization image can be used to predict the occurrence of PJK after posterior osteotomy and long-segment fusion fixation in adult spinal deformity. If the patient's T 8-L 2 vertebral hC 7-VSO is too large, it indicates a higher risk of postoperative PJK. The best predictive index is hC 7-L 2, and the cut-off value is 2.54 cm.

Risk factors for proximal junctional kyphosis after spinal deformity surgery: A meta-analysis / 中国组织工程研究

BACKGROUND: Proximal junctional kyphosis is a common complication after spinal deformity surgery, which can lead to a variety of adverse clinical outcomes. Therefore, it is necessary to analyze the risk factors that may lead to proximal junctional kyphosis after surgery, in order to expand our understanding of proximal junctional kyphosis and provide guidance for its prevention. OBJECTIVE: To evaluate the risk factors of proximal junctional kyphosis after spinal deformity surgery using meta-analysis. METHODS: A systematic literature search was performed using PubMed, EMbase, Cochrane, CNKI and Wanfang Medical Database (up to May 2019). The quality of literatures was assessed and selected according to the inclusion criteria and exclusion criteria. Relevant data were extracted. RevMan 5.3 software was used for data analysis and the data were dealt by meta-analysis. The meta-analysis results were evaluated. RESULTS AND CONCLUSION: (1) This study included 26 studies involving 4 498 patients of whom 921 with proximal junctional kyphosis. The incidence of proximal junctional kyphosis after spinal orthopedic surgery was 25%. (2) There were significant differences between the proximal junctional kyphosis and non-proximal junctional kyphosis groups in age, body mass index, osteoporosis, number of surgical vertebral bodies, the upper instrumented vertebra to the thoracolumbar segment (T10-L1), the lower instrumented vertebra to the sacrum/pelvis/ilium, postoperative proximal kyphosis angle, lumbar lordosis and sagittal vertical axis, changes in proximal kyphosis angle, lumbar lordosis and sagittal vertical axis (P 0.05). (4) Our meta-analysis showed that age, body mass index, osteoporosis, the number of operative vertebrae > 5 at fixation segment, the upper instrumented vertebra internal fixation to thoracolumbar segment (T10-L1), the lower instrumented vertebra fixation to sacrum/pelvis/ilium, postoperative proximal kyphosis angle, lumbar lordosis and sagittal vertical axis, changes in proximal kyphosis angle, lumbar lordosis and sagittal vertical axis were the main risk factors for proximal junctional kyphosis. The incidence of proximal junctional kyphosis can be reduced by intervening the high-risk population and making the suitable surgical procedures. Proximal junctional kyphosis was due to a variety of non-surgical and surgical factors. More rigorous epidemiological studies are needed to provide reliable evidence for reducing the incidence of proximal junctional kyphosis.

Influencing factors of proximal junctional kyphosis in adult scoliosis patients after surgery / 第二军医大学学报

Objective To measure the spinal sagittal parameters and pelvic parameters of adult scoliosis patients, and to explore the influencing factors of proximal junctional kyphosis (PJK) after surgery. Methods The clinical data of 45 adult scoliosis patients, who underwent surgical treatment in our hospital from Jan. 2014 to Sep. 2016, were retrospectively analyzed. The participants were divided into PJK group and non-PJK group according to whether proximal junctional angle (PJA) was >20°. Before operation, at 1 week after operation and at the last follow-up, the thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS) were measured and analyzed on the anteroposterior and lateral X-ray films of the spine. The main influencing factors of PJK in adult scoliosis patients after surgery were analyzed using logistic multivariate regression analysis. Results Nineteen patients were enrolled in the PJK group and 26 in the non-PJK group. There were no significant differences in the gender, age, followup time, upper instrumented vertebra or lower instrumented vertebra between the two groups (all P>0.05). Compared with the non-PJK group, the LL, SVA and PT at the last follow-up, and PT before operation were significantly larger in the PJK group, and the SS before operation and at the last follow-up were significantly lower (all P0.05). Logistic multivariate regression analysis showed that TK and SS before operation, and TK, LL and PT at the last follow-up were the main influencing factors of PJK. Conclusion TK and SS before operation, and TK, LL and PT at the last follow-up are the main influencing factors of PJK.

A biomechanical study on proximal junctional kyphosis following long-segment posterior spinal fusion

Posterior long-segment spinal fusion may lead to proximal junctional kyphosis (PJK). The present study sought to identify the appropriate fusion levels required in order to prevent PJK using finite element analysis. A finite element model was constructed based on the whole-spine computed tomography findings of a healthy adult. Nine commonly used posterior spinal fusion methods were selected. Stress on the annulus fibrosis fibers, the posterior ligamentous complex, and the vertebrae after various spinal fusions in the upright position were compared. This study was divided into two groups: non-fusion and fusion. In the former, the stress between the T10 and the upper thoracic vertebrae was higher. Comparing thoracic and lumbar segments in the fusion group, the peak stress values of the upper instrumented vertebrae (UIV) were mainly observed in T2 and L2 whilst those of the UIV+1 were observed in T10 and L2. After normalization, the peak stress values of the UIV and UIV+1 were located in T2 and L2. Similarly, the peak stress values of the annulus fibrosus at the upper adjacent level were on T10 and L2 after normalization. However, the peak stress values of the interspinal/supraspinal complex forces were concentrated on T11, T12, and L1 after normalization whilst the peak stress value of the pedicle screw was on T2. Controversy remains over the fusion of T10, and this study simulated testing conditions with gravitational loading only. However, further assessment is needed prior to reaching definitive conclusions.

Proximal Junctional Kyphosis and Proximal Junctional Failure Following Adult Spinal Deformity Surgery

The purpose of this review is the current understanding of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) following adult spinal deformity (ASD) surgery. We carried out a systematic search of PubMed for literatures published up to September 2017 with “proximal junctional kyphosis,”“proximal junctional failure,” and “adult spinal deformity” as search terms. A total of 98 literatures were searched. The 37 articles were included in this review. PJK is multifactorial in origin and likely results from variable risk factors. PJF is a progressive form of the PJK spectrum including bony fracture, subluxation between UIV and UIV+1, failure of fixation, neurological deficit, which may require revision surgery for proximal extension of fusion. Soft tissue protections, adequate selection of the UIV, prophylactic rib fixation, hybrid instrumentation such as hooks, vertebral cement augmentation at UIV and UIV+1, adequate selection material of rods and age-appropriate spinopelvic alignment goals are strategies to minimize PJK and PJF. The ability to perform aggressive global realignment of spinal deformities has also led to the discovery of new complications such as the PJK and PJF. Continuous research on PJK and PJF should be proceeded in order to comprehend the pathophysiology of these complications.

Risk Factors for Proximal Junctional Kyphosis / 中国康复理论与实践

Objective To investigate the risk factors of proximal junctional kyphosis (PJK) after posterior long segmental lumbar fusion for degenerative lumbar disease. Methods From October, 2012 to July, 2014, 118 degenerative lumbar disease patients who accepted posteri-or long segmental fusion and followed up at least 1.5 years were reviewed. All the PJK were evaluated with X-ray. Results Sixty-six pa-tients completed the follow-up (mean of 3.2 years), in which 12 patients with PJK (PJK group), and the others without (non-PJK group, n=54). There was significant difference in body mass index, bone density and the last Oswestry Disability Index scores (t>2.194, P3.862, P10° (OR=5.789, 95%CI:1.075~31.183) were the independent risk factors of PJK. Conclusion Osteoporosis, UIV located in the thoracolumbar segment (T11-L1) and the pre-surgery PJK angle>10° are risk factors of PJK af-ter posterior long segmental lumbar fusion.

Proximal junctional kyphosis after posterior hemivertebra resection and instrumented fusion in young children with congenital scoliosis / 中华外科杂志

Objective@#To investigate the risk factors of proximal junctional kyphosis(PJK) in young children who underwent posterior hemivertebra resection and instrumented fusion.@*Methods@#This study reviewed the charts and radiographs of 136 consecutive young children with congenital scoliosis who underwent posterior hemivertebra resection and instrumented fusion in Department of Orthopaedics, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School from January 2009 to June 2014, including 75 males and 61 females, with an average age of (5.0±1.7)years(3-10 years). Proximal junctional angle(PJA), spino-pelvic parameters and segmental kyphosis (SK) were recorded pre- and post-operation and at last follow-up.The changes of PJA and radiographic features of proximal junction were also observed.χ2 test and t-test were used to analyzed enumeration data and measurement data, respectively.@*Results@#The average follow-up period was (32.8±10.3)months (ranging from 24 to 73 months) by June 2016. Among these patients, PJK occurred in 19 cases. Fifteen patients developed PJK during the first 3 months after surgery.The most common type of PJK was ligamentous failure.Compared with the non-PJK group (22.2%, 37.6%, 13.7%), the PJK group showed higher rate of preoperative TK>40°(9/19), fusion levels >4 (13/19) and greater SK change > 30°(9/19)(χ2=7.259, 6.375, 12.368; all P<0.05), while there were no difference between the two groups in terms of preoperative PJA, lumbar lordosis, SVA and upper instrument vertebra location(all P>0.05). The average PJA increased from 7.5°±2.9° to 21.3°±4.3° at 3 months after surgery to 20.6°±3.7° at the final follow-up visit in the PJK group.At the time of the final follow-up visit, ten patients received brace treatment, with no significant progression of PJA.@*Conclusions@#PJK might mainly occurs within 3 months postoperatively.Its prognostic factors include preoperative hyperkyphosis, over correction of kyphosis and ligamentous failure.

Risk Factors of Proximal Junctional Kyphosis after Multilevel Fusion Surgery: More Than 2 Years Follow-Up Data

OBJECTIVE: Proximal junctional kyphosis (PJK) is radiologic finding, and is defined as kyphosis of >10° at the proximal end of a construct. The aim of this study is to identify factors associated with PJK after segmental spinal instrumented fusion in adults with spinal deformity with a minimum follow-up of 2 years. METHODS: A total of 49 cases of adult spinal deformity treated by segmental spinal instrumented fusion at two university hospitals from 2004 to 2011 were enrolled in this study. All enrolled cases included at least 4 or more levels from L5 or the sacral level. The patients were divided into two groups based on the presence of PJK during follow-up, and these two groups were compared to identify factors related to PJK. RESULTS: PJK was observed in 16 of the 49 cases. Age, sex and mean follow-up duration were not statistically different between two groups. However, mean bone marrow density (BMD) and mean back muscle volume at the T10 to L2 level was significantly lower in the PJK group. Preoperatively, the distance between the C7 plumb line and uppermost instrumented vertebra (UIV) were no different in the two groups, but at final follow-up a significant intergroup difference was observed. Interestingly, spinal instrumentation factors, such as, receipt of a revision operation, the use of a cross-link, and screw fracture were no different in the two groups at final follow-up. CONCLUSION: Preoperative BMD, sagittal imbalance at UIV, and thoracolumbar muscle volume were found to be strongly associated with the presence of PJK.

Complications and Risk Factors of Surgery for Adult Spine Deformity / 대한정형외과학회잡지

Demand for surgical management of adult spine deformity has increased due to a recent increase in the elder population, development of surgical techniques, and increased desire for a better quality of life. More surgeries led to more and various complications. Complications of surgery for adult spine deformity have been reported from 37% to 53% depending on the types of disease, cause, and patient. This rate is higher than complications from general spine surgeries. Complications of surgery for adult spine deformity include; infection, excessive bleeding, nerve injury, pseudarthrosis, adjacent segment disease, and iliac screw complication. Factors influencing these complications include; old age, diabetes, steroid use, and osteoporosis. Proximal junctional kyphosis (PJK) is an abnormal kyphosis at the proximal level of the instrument after spine deformity surgery. Risk factors for PJK include; injury of paravertebral muscles and posterior ligament complex, over- and under-correction of coronal sagittal imbalance, age older than 55 years, and osteoporosis. There is a high risk of unexpected complications during surgery for adult spine deformity. Patients with degenerative spine sagittal imbalance are more prevalent in Korea than in Western countries. They tend to be old, have underlying diseases and osteoporosis, making them susceptible to complications related to instrumentation. Postoperative satisfaction tends to be low thus surgeons need to take care when selecting surgical methods and fusion level.

Proximal Junctional Kyphosis: Diagnosis, Pathogenesis, and Treatment

Proximal junctional kyphosis (PJK) is a common radiographic finding after long spinal fusion. A number of studies on the causes, risk factors, prevention, and treatment of PJK have been conducted. However, no clear definition of PJK has been established. In this paper, we aimed to clarify the diagnosis, prevention, and treatment of PJK by reviewing relevant papers that have been published to date. A literature search was conducted on PubMed using "proximal junctional", "proximal junctional kyphosis", and "proximal junctional failure" as search keywords. Only studies that were published in English were included in this study. The incidence of PJK ranges from 5% to 46%, and it has been reported that 66% of cases occur 3 months after surgery and approximately 80% occur within 18 months. A number of studies have reported that there is no significantly different clinical outcome between PJK patients and non-PJK patients. One study showed that PJK patients expressed more pain than non-PJK patients. However, recent studies focused on proximal junctional failure (PJF), which is accepted as a severe form of PJK. PJF showed significant adverse impact in clinical aspect such as pain, neurologic deficit, ambulatory difficulties, and social isolation. Numerous previous studies have identified various risk factors and reported on the treatment and prevention of PJK. Based on these studies, we determined the clinical significance and impact of PJK. In addition, it is important to find a strategic approach to the proper treatment of PJK.

Cifosis de unión proximal en curvas Lenke 5C. Comparación entre cirugía anterior y cirugía posterior / Proximal junctional kyphosis in lenke c5 curves. A comparison between anterior and posterior surgery

Introducción: El balance sagital es crítico para los resultados a largo plazo en el manejo quirúrgico de la escoliosis idiopática del adolescente. La cifosis de unión se podría definir como un hallazgo radiológico en la transición de la columna fusionada y la columna móvil en pacientes asintomáticos. El objetivo de este trabajo fue comparar la cifosis de unión proximal posoperatoria en curvas Lenke 5C con dos técnicas quirúrgicas distintas: la instrumentación anterior y la instrumentación posterior. Materiales y Métodos: Estudio retrospectivo, controlado no aleatorizado, de 37 pacientes con escoliosis idiopática del adolescente, curvas Lenke 5C con fusión corta, de vértebra límite a vértebra límite. Grupo 1: 18 pacientes con artrodesis anterior instrumentada y Grupo 2: 19 pacientes con artrodesis posterior instrumentada. Los parámetros sagitales radiológicos medidos fueron: 1) línea de plomada de C7, 2) cifosis de unión, 3) cifosis torácica, 4) lordosis lumbar, con un seguimiento mínimo de 2 años. Resultados: Grupo 1: aumento de la cifosis de unión entre el preoperatorio y el seguimiento a los 2 años de 6,27° (p = 0,0002). La incidencia de cifosis de unión patológica fue del 17 por ciento. Grupo 2: aumento de la cifosis de unión entre el preoperatorio y el seguimiento de 4,63° (p = 0,0004). La incidencia de cifosis de unión patológica fue del 16 por ciento. Conclusión: No hubo diferencias significativas entre ambos grupos en la incidencia de cifosis de unión patológica.

Background: Sagittal balance is critical for long-term results in the surgical handling of adolescent idiopathic scoliosis. Proximal junctional kyphosis could be defined as a radiographic findings in the fused and mobile spine transition in asymptomatic patients. Objective: To compare post-surgical proximal junctional kyphosis in Lenke C5 curves with two different surgical techniques: anterior and posterior instrumentation. Methods: Retrospective, controlled, non-randomized study of 37 patients with Lenke C5 adolescent idiopathic scoliosis, with short fusion from end-vertebra to end-vertebra. Group 1: 18 patients with anterior instrumented arthrodesis, and Group 2: 19 patients with posterior instrumented arthrodesis. The radiographic sagittal parameters measured were: 1) plumbline from the C7, 2) junctional kyphosis, 3) thoracic kyphosis, and 4) lumbar lordosis; with a minimum follow-up of two years. Results: Group 1: increase of junctional kyphosis between the preoperative period and a two-year follow-up, 6.27° (p = 0.0002). The incidence of pathologic junctional kyphosis was 17%. Group 2: increase of junctional kyphosis between the preoperative period and the follow- up, 4.63° (p = 0.0004). The incidence of pathologic junctional kyphosis was 16%. Conclusion: There were no significant differences between groups in the incidence of pathologic junctional kyphosis.

Clinical Outcomes and Complications after Pedicle Subtraction Osteotomy for Fixed Sagittal Imbalance Patients : A Long-Term Follow-Up Data

OBJECTIVE: Clinical, radiographic, and outcomes assessments, focusing on complications, were performed in patients who underwent pedicle subtraction osteotomy (PSO) to assess correction effectiveness, fusion stability, procedural safety, neurological outcomes, complication rates, and overall patient outcomes. METHODS: We analyzed data obtained from 13 consecutive PSO-treated patients presenting with fixed sagittal imbalances from 1999 to 2006. A single spine surgeon performed all operations. The median follow-up period was 73 months (range 41-114 months). Events during perioperative course and complications were closely monitored and carefully reviewed. Radiographs were obtained and measurements were done before surgery, immediately after surgery, and at the most recent follow-up examinations. Clinical outcomes were assessed using the Oswestry Disability Index and subjective satisfaction evaluation. RESULTS: Following surgery, lumbar lordosis increased from -14.1degrees +/- 20.5degrees to -46.3degrees +/- 12.8degrees (p < 0.0001), and the C7 plumb line improved from 115 +/- 43 mm to 32 +/- 38 mm (p < 0.0001). There were 16 surgery-related complications in 8 patients; 3 intraoperative, 3 perioperative, and 10 late-onset postoperative. The prevalence of proximal junctional kyphosis (PJK) was 23% (3 of 13 patients). However, clinical outcomes were not adversely affected by PJK. Intraoperative blood loss averaged 2,984 mL. The C7 plumb line values and postoperative complications were closely correlated with clinical results. CONCLUSION: Intraoperative or postoperative complications are relatively common following PSO. Most late-onset complications in PSO patients were related to PJK and instrumentation failure. Correcting the C7 plumb line value with minimal operative complications seemed to lead to better clinical results.