Incidence Of Proximal Junctional Kyphosis Research Articles

Radiographic and Clinical Outcomes of Transverse Process Hook Placement at the Proximal Thoracic Upper Instrumented Vertebra in Adult Spinal Deformity Surgery.

Few studies have reported radiographic and clinical outcomes of transverse process hook (TPH) placement at the proximal thoracic upper instrumented vertebra (UIV) in adult spinal deformity (ASD) surgery. This study aims to investigate radiographic and clinical outcomes of TPH placement at the UIV for ASD surgery. This is a retrospective cohort of 56 patients with ASD (age, 59 ± 13 years; followup, 44 ± 19 months) from Johns Hopkins Hospital, who underwent long posterior spinal fusion to the proximal thoracic spine (T2-5). Visual analogue scale (VAS) for back pain, Oswestry Disability Index (ODI), 36-item Short Form health survey scores, thoracic kyphosis (TK), lumbar lordosis, sacral slope, pelvic tilt, pelvic incidence, proximal junctional kyphosis (PJK) angle, PJK incidence, pattern of PJK, grades of TPH dislodgement, revision surgery, and factors associated with high-grade TPH dislodgement were analyzed. VAS for back pain and ODI values improved significantly from preoperatively to final follow-up. Mean change in PJK angle was 12° (range, 0.5°-43°). Twenty patients (36%) developed PJK, of whom 13 had compression fractures at 1 vertebra distal to the UIV (UIV-1). Final TPH position was stable in 42 patients (75%). In most patients (86%), TPH dislodgement did not progress after 6-month postoperative follow-up. Three patients (5.3%) underwent revision surgery to extend the fusion because of symptomatic PJK. Unstable TPH position was associated only with revision surgery and TK. TPH placement at the proximal thoracic UIV for long fusion showed favorable clinical and radiographic outcomes in terms of the incidence of PJK and mean PJK angle at mean 44-month follow-up. TPHs placed in the proximal thoracic UIV were in stable position in 75% of patients. Compression fracture at UIV-1 was the most common pattern of PJK. PJK angle progression was greater in revision cases and in patients with greater preoperative thoracic kyphosis.

Spinopelvic morphology impacts on postoperative proximal junctional kyphosis in congenital scoliosis with thoracolumbar hemivertebrae.

It aims to investigate the lumbar and pelvic morphology in congenital scoliosis with thoracolumbar hemivertebrae and its impact on proximal junctional kyphosis (PJK) incidence after hemivertebra resection and short fusion. 23 congenital scoliosis patients with thoracolumbar hemivertebra aged between 10 and 18years were enrolled in the retrospective study. Spinopelvic sagittal parameters were analyzed on whole-spine standing lateral radiographs preoperatively, one-week postoperatively and at the final follow-up. Pearson correlations were calculated for local kyphosis (LK), lumbar and pelvic morphology parameters. Binary logistic regression and receiver operating characteristics (ROC) curve analysis were performed to identify the risk factors for PJK. Thoracolumbar hemivertebra caused LK of 29.2° ± 17.3°, an increased lumbar lordosis (LL) (-64.7° ± 16.3°), lower LL apex (52.2% at L5), and small pelvic incidence (PI) (36.8° ± 6.6°). LK was correlated with lumbar morphology parameters, including LL (r = -0.837), upper arc of LL (LLUA) (r = -0.879), thoracolumbar kyphosis (TLK) (r = 0.933), thoracic kyphosis (TK) (r = 0.762) and TK apex (TKA) (r = -0.749). Surgical treatment improved the lumbar morphology, but not pelvic morphology. At the final follow-up, LL had returned to its preoperative value (p = 0.158). PJK occurred in 30.4% of cases as a compensatory mechanism. Preoperatively, significant differences of parameters between non-PJK and PJK groups were observed in LK and TLK. Binary logistic regression identified three independent risk factors for PJK: preoperative LLA (OR = 0.005, 95%CI = 0.000-0.287, p = 0.011), preoperative TLK (OR = 1.134, 95%CI = 1.001-1.286, p = 0.048), and preoperative lumbar lordosis morphology type (OR = 5.507, 95%CI = 1.202-25.227, p = 0.028). However, residual LK after surgery was not correlated with PJK incidence. ROC curve analysis verified that preoperative TLK > 22.59° was associated with increased PJK incidence after surgery. Lumbar morphology changes as a compensatory mechanism beneath the thoracolumbar hemivertebra. However, a stable pelvis tends to allow the LL to return to its preoperative value. PJK occurred as a cranial compensatory mechanism for increasing LL and corrected TLK. A larger TLK (> 22.59°) was an independent risk factor for PJK incidence in patients with type 2 and 3A lumbar lordosis morphology.

Simplified S1 vertebral bone quality score independently predicts proximal junctional kyphosis after surgery for degenerative lumbar scoliosis

ObjectiveOur study aimed to assess the effectiveness of the simplified S1 vertebral bone quality (VBQ) score in predicting the incidence of proximal junctional kyphosis (PJK) after surgery for degenerative lumbar scoliosis (DLS).MethodsWe reviewed 122 patients with DLS who underwent posterior lumbar decompression and long-segment fusion surgery in our hospital from January 2016 to December 2020. The patients were classified into PJK group and non-PJK group. S1 VBQ scores are determined by signal intensity measurements taken from the mid-sagittal plane of T1-weighted non-contrast MRI. Logistic regression analysis was used to identify factors associated with PJK. Receiver-operating characteristic curve (ROC) analysis was used to evaluate the value of S1 VBQ score in predicting pedicle PJK after DLS.Results122 DLS patients (90 females and 32 males) met the inclusion criteria. In addition, 27 patients (22.13%) had PJK at the time of last follow-up. VBQ was higher in PJK patients than non-PJK patients (3.58 ± 0.67 vs. 3.08 ± 0.54, p < 0.001). Preoperatively, patients in the PJK group had a greater TLK than those in the non-PJK group (20.00 ± 6.22 vs. 16.86 ± 5.38, p = 0.011). After surgery, patients in the PJK group had greater TLK (p < 0.001) and PJA (p < 0.001) compared with the non-PJK group. At final FU, patients in the PJK group had greater TK (p = 0.002), TLK (p < 0.001), SVA (p < 0.001), and PJA (p < 0.001) than patients in the non-PJK group (Table 4). In multivariate logistic regression analysis, higher VBQ score (OR 4.565, 95% CI 1.43–14.568, p = 0.010), advanced age (OR 1.119, 95% CI 1.021–1.227, p = 0.016), and larger TLK (OR 1.191, 95% CI 1.041–1.362, p = 0.011) were significant predictors of postoperative PJK in patients with DLS (Table 6). A statistically significant positive correlation existed between VBQ score and PJA change (r = 0.370, p < 0.001). We created ROC curves for VBQ scores as predictors of PJK with a diagnostic accuracy of 72.1% (95% CI 60.15–82.9%.The ideal limit for the VBQ score was 3.205 (sensitivity: 77.8%, specificity: 81.4%).ConclusionTo the best of our knowledge, this is the first study to evaluate the effectiveness of the S1 VBQ score in predicting postoperative PJK in DLS. Our study included major risk factors and found that S1 VBQ score was a significant predictor of PJK in patients undergoing DLS surgery. The higher the S1 VBQ score, the higher the probability of PJK.

Patient-Specific Surgical Correction of Adolescent Idiopathic Scoliosis: A Systematic Review.

The restoration of sagittal alignment is fundamental to the surgical correction of adolescent idiopathic scoliosis (AIS). Despite established techniques, some patients present with inadequate postoperative thoracic kyphosis (TK), which may increase the risk of proximal junctional kyphosis (PJK) and imbalance. There is a lack of knowledge concerning the effectiveness of patient-specific rods (PSR) with measured sagittal curves in achieving a TK similar to that planned in AIS surgery, the factors influencing this congruence, and the incidence of PJK after PSR use. This is a systematic review of all types of studies reporting on the PSR surgical correction of AIS, including research articles, proceedings, and gray literature between 2013 and December 2023. From the 28,459 titles identified in the literature search, 81 were assessed for full-text reading, and 7 studies were selected. These included six cohort studies and a comparative study versus standard rods, six monocentric and one multicentric, three prospective and four retrospective studies, all with a scientific evidence level of 4 or 3. They reported a combined total of 355 AIS patients treated with PSR. The minimum follow-up was between 4 and 24 months. These studies all reported a good match between predicted and achieved TK, with the main difference ranging from 0 to 5 degrees, p > 0.05, despite the variability in surgical techniques and the rods' properties. There was no proximal junctional kyphosis, whereas the current rate from the literature is between 15 and 46% with standard rods. There are no specific complications related to PSR. The exact role of the type of implants is still unknown. The preliminary results are, therefore, encouraging and support the use of PSR in AIS surgery.

Spondylodiscitis instrumented fusion, a prospective case series on a standardized neurosurgical protocol with long term follow up

PurposeTo investigate the fusion construct properties, construct length, intervertebral prosthesis (IVP) selection, bone grafting methods, complications management, and follow-up outcomes of spondylodiscitis fusion. MethodThis case series was conducted in Al-Zahra University referral hospital from March 2016 to November 2021. All the surgery-eligible patients were enrolled. Those who did not participate or failed the neurosurgical intervention were excluded. A unified neurosurgical protocol was defined. After operation and follow-up, all variables were documented. IBM SPSS v.26 was used for data analysis. P-value ≤ 0.05 was considered significant. ResultNinety-two patients were reviewed in the final analysis with 65.2 % males. The mean age was 55.07 ± 14.22 years old. The most frequent level of pathology and surgery was the lumbar spine (48.9 %). Short and long constructs were almost equally used (57.6 and 42.4 %, respectively). Bone graft mixture was the dominant IVP (75 %). The most frequent persistent postoperative symptom was back pain (55.4 %), while the neurological deficits resolution rate was 76.7 %. The fusion rate was 92.3 %. Proximal junctional kyphosis incidence was 16.3 % and had a significant association with on-admission neurological symptoms, thoracic and thoracolumbar junction involvements (p < 0.05). Follow-up Oswestry disability index scores showed 44.6 % of the patients had mild or no functional disabilities. Advanced age, On-admission deficits, comorbidities, titanium cages, and poor fusion status were associated with poor functional outcomes and higher mortality rates (P < 0.05). ConclusionThe introduced neurosurgical protocol could effectively achieve acceptable SD treatment, spine stabilization, and fusion with low long-term surgical complications. Autologous bone graft mixture in comparison to titanium cages showed a higher fusion rate with a lower mortality rate. Patients with older age, neurological symptoms, and comorbidities are expected to experience less favorable clinical outcomes.

Restoring the ideal Roussouly sagittal alignment in Lenke 5 adolescent idiopathic scoliosis patients: a method for decreasing the risk of proximal junctional kyphosis.

Although the Roussouly classification has been widely used in surgical planning for adult scoliosis patients, little is known about whether it can be used to guide sagittal correction for adolescent idiopathic scoliosis (AIS) patients. The purpose of this study was to explore whether the Roussouly classification could be used to help surgeons restore the ideal sagittal alignment for AIS patients to avoid the development of proximal junctional kyphosis (PJK). In this retrospective cohort study, eighty-seven patients with Lenke 5 AIS who underwent surgery from January 2010 to August 2020 were enrolled and divided into two groups: the PJK group and the non-PJK group. All patients were classified into "current types" and "ideal types" according to two versions of the Roussouly classification, and the mismatch rate was evaluated in terms of the consistency between their current type and ideal type. Student's t test, Mann‒Whitney U test, Pearson's Chi-square test, and others were used to compare the two groups regarding patient demographic characteristics (age, sex, Risser sign, etc.) and radiographic parameters (sagittal vertical axis [SVA]; thoracic kyphosis [TK]; thoracolumbar junctional kyphosis [TLK]; lumbar lordosis [LL]; pelvic incidence [PI]; pelvic tilt [PT]; sacral slope [SS]; upper instrumented vertebra [UIV]; lower instrumented vertebra [LIV]; etc.). Multivariate logistic regression with backwards stepwise selection was performed to identify the risk factors for PJK. PJK was observed in 16 out of 87 patients (18.4%) until the final follow-up. The incidence of PJK was significantly higher in the patients not matching their ideal type than in those who did after surgery (60.9% vs. 3.1%, p = 0.000). The patients with ideal Type 1 had the highest incidence of PJK, while the lowest incidence was observed in patients with ideal Type 2 (50.0% vs. 5.1%, p = 0.000). The PJK group had greater TK, LL, and PI-LL than the non-PJK group before and after surgery. The postoperative PJA in the PJK group was also larger than that in the non-PJK group. Multivariate logistic regression revealed that postoperative Roussouly type mismatch was significantly associated with the occurrence of PJK (OR = 64.2, CI = 9.6-407.1, p = 0.000). The Roussouly classification could serve as a prognostic tool for PJK in Lenke 5 AIS patients. Corrective surgery should restore sagittal alignment with respect to the patient's ideal sagittal profile (according to the Roussouly classification based on the PI) to decrease the incidence of PJK in AIS patients.

Clinical and Economic Impact of Proximal Junctional Kyphosis on Pediatric and Adult Spinal Deformity Patients.

The common goal of pediatric and adult spinal reconstructive procedures is to minimize long-term risk of disability, pain, and mortality. A common complication that has proved particularly problematic in the adult spinal deformity population and that has been an area of increased research and clinical focus is proximal junctional kyphosis (PJK). The incidence of PJK ranges from 10%-40% based on criteria used to define the condition. Clinically, PJK complication is associated with increased pain, decreased self-image and Scoliosis Research Society scores, and severe neurological injuries affecting the patient's quality of life. Economically, direct costs of PJK complication-associated revision surgery ranges from $20,000 to $120,000, which places an enormous burden on patients, providers, and payers. To mitigate the risk of PJK occurrence postoperatively, it is paramount to develop consistent guidelines in defining and classifying PJK in addition to extensive preoperative planning and risk stratification that is patient specific. This article will provide an overview on the clinical and economic impact of PJK in pediatric and adult spine deformity patients with an emphasis on the role of patient factors and predictive analytics, challenges in developing a consistent PJK classification, and current treatment and prevention strategies.

Risk factors of proximal junctional kyphosis after surgical correction of spinal deformities caused by Scheuermann’s disease

Objective. To identify risk factors for the development of Proximal Junctional Kyphosis (PJK) in patients with Scheuermann’s kyphosis operated on using segmental instrumentation.Material and Methods. The study group consisted of 43 patients (13 females, 30 males), mean age was 17 years, and mean postoperative follow-up was 6 years. Spondylograms with a patient in a standing position performed before surgery, a week after surgery, and at the end of the follow-up period were analyzed. Radiological parameters were studied: cervical lordosis, absolute rotation angle, thoracic entry angle, T1 vertebral body tilt, neck tilt, skull tilt, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, vertebral and pelvic parameters (Pelvic Incidence, Pelvic Tilt, Sacral Slope), sagittal vertical axis, proximal junctional angle (PJA), and length of the posterior spinal fusion.Results. The mean PJA before surgery was 7° [3°; 8°], immediately after surgery – 10° [8°; 13°], by the end of the follow-up period – 25°[19°; 32°]. The incidence of PJK by the end of the follow-up period was 79.1 % (in 34 out of 43 patients). The initial value of thoracic kyphosis was 77° [72°; 86°], after surgery – 41° [31°; 46°], at the last examination – 43° [35°; 53°]. The inclination of the T1 vertebral body in the sagittal plane before surgery was 39° [30°; 45°], at the stages of follow-up – 33° [22°; 37°] and 39° [27°; 45°]. Some significant predictors were identified. An increase in the inclination of the T1 vertebral body (p = 0.005) by k° is associated with an increase in the risk of PJK by 1.19k [1.08k; 1.37k] times, and an increase of thoracic kyphosis by k° (p = 0.023) – by 1.12k (1.03k; 1.27k) times. The formula for preoperative predicting the likelihood of this complication is: P (PJK) = 1 - 1/(1 + exp (-23.14 + 0.26 × T1 + 0.21 × TK)), where P(PJK) is the probability of proximal junctional kyphosis; exp(z) is the exponential function to the power of z; T1 (T1 vertebral body tilt) and TK (thoracic kyphosis) are preoperative values of variables. Using ROC analysis, the threshold value for predicting PJK was determined to be 74.2 %, that is, the development of PJK was predicted in patients with a PJK probability greater than the threshold value calculated by the model formula. The predictive ability of the multivariate model was tested on the basis of the available initial data with a known final result. The prediction was correct in 41 cases out of 43.Conclusion. Using the multivariate logistic regression method, two mutually independent multiplicative indicators were determined for predicting PJK with high accuracy (sensitivity 94.1 %, specificity 100.0 %) – inclination of the T1 vertebral body and thoracic kyphosis.

Use of global sagittal flexibility to predict proximal junctional kyphosis after spinal deformity surgery.

Sagittal alignment is an important predictor of functional outcomes after surgery for adult spinal deformity (ASD). A rigid spinal column may create a large lever arm that may impact the rate of proximal junctional kyphosis (PJK) after ASD surgery. In this study, the authors sought to determine whether relatively low preoperative global spinal flexibility (i.e., rigid spine) predicts increased incidence of PJK at 1 year after ASD surgery. The authors retrospectively reviewed long-segment thoracolumbar fusions with pelvic fixation performed at a single tertiary care center between October 2015 and September 2020 in patients with a minimum of 1-year radiographic and clinical follow-up. Two cohorts were established on the basis of the optimal value for spinal flexibility, as defined by the absolute difference between the preoperative standing and supine C7 sagittal vertical axes, which the authors termed global sagittal flexibility (GSF). Demographic information, radiographs, various associated complications, and patient-reported outcome measures (PROMs) were analyzed. Eighty-five patients met the inclusion criteria. Receiver operating characteristic (ROC) analysis using GSF to predict an increase in the proximal junctional sagittal Cobb angle (PJCA) greater than or equal to 10° at 1-year follow-up provided an area under the curve of 0.64 and identified an optimal GSF threshold value of 3.7 cm. Patients with GSF > 3.7 cm were considered globally flexible (48 patients), and those with GSF ≤ 3.7 cm were classified as rigid (37 patients). Rigid patients were noted to have a significantly higher risk of ΔPJCA ≥ 10° at 1-year follow-up (51.4% vs 29.3%, p = 0.049). No changes in the reoperation rates or PROMs based on GSF were observed in the 1- or 2-year postoperative window. Based on these retrospective data, preoperative global spinal rigidity portends an independently elevated risk for the development of PJK after ASD surgery. No differences in other complication rates or PROMs data were observed between groups. Data collection was limited to a 2-year postoperative window; therefore, longer follow-up is required to further elucidate the relationship between rigidity and reoperation rates. Based on these retrospective data, flexibility may influence the outcomes of patients with ASD.

Functional Alignment Within the Fusion in Adult Spinal Deformity (ASD) Improves Outcomes and Minimizes Mechanical Failures.

Retrospective review of an adult deformity database. To identify pelvic incidence (PI) and age-appropriate physical function alignment targets using a component angle of T1-pelvic angle within the fusion to define correction and their relationship to proximal junctional kyphosis (PJK) and clinical outcomes. In preoperative planning, a patient's PI is often utilized to determine the alignment target. In a trend toward more patient-specific planning, age-specific alignment has been shown to reduce the risk of mechanical failures. PI and age have not been analyzed with respect to defining a functional alignment. A database of patients with operative adult spinal deformity was analyzed. Patients fused to the pelvis and upper-instrumented vertebrae above T11 were included. Alignment within the fusion correlated with clinical outcomes and PI. Short form 36-Physical Component Score (SF36-PCS) normative data and PI were used to compute functional alignment for each patient. Overcorrected, under-corrected, and functionally corrected groups were determined using T10-pelvic angle (T10PA). In all, 1052 patients met the inclusion criteria. T10PA correlated with SF36-PCS and PI (R=0.601). At six weeks, 40.7% were functionally corrected, 39.4% were overcorrected, and 20.9% were under-corrected. The PJK incidence rate was 13.6%. Overcorrected patients had the highest PJK rate (18.1%) compared with functionally (11.3%) and under-corrected (9.5%) patients ( P <0.05). Overcorrected patients had a trend toward more PJK revisions. All groups improved in HRQL; however, under-corrected patients had the worst 1-year SF36-PCS offset relative to normative patients of equivalent age (-8.1) versus functional (-6.1) and overcorrected (-4.5), P <0.05. T10PA was used to determine functional alignment, an alignment based on PI and age-appropriate physical function. Correcting patients to functional alignment produced improvements in clinical outcomes, with the lowest rates of PJK. This patient-specific approach to spinal alignment provides adult spinal deformity correction targets that can be used intraoperatively.

Analysis of factors associated with proximal junctional kyphosis after surgery for Lenke type 5 adolescent idiopathic scoliosis

Objective: To investigate the risk factors associated with the development of proximal junctional kyphosis (PJK) after posterior spinal fusion for in children with Lenke type 5 adolescent idiopathic scoliosis (AIS). Methods: It was a retrospective case-control study that included medical records of 98 children with Lenke type 5 AIS who underwent posterior orthopedic surgery under general anesthesia at the Honghui Hospital Affiliated to Xi'an Jiaotong University from January 2013 to December 2018. There were 23 males and 75 females with a mean age of (14.5±2.2) years (10-18 years). Patients were divided into PJK and non-PJK groups according to whether the posterior junctional angle (PJA) was greater than 10° and increased for more than 10° from the preoperative period at the the last follow-up. Univariate analysis was used to analyze the correlation of general data of the children with occurrence of PJK after the operation. Multivariate logistic regression analysis was used to analyze the risk factors of postoperative PJK. Results: There were 35 cases in the PJK group and 63 cases in the non-PJK group. The PJK and non-PJK groups were followed up for (35.6±7.3) months and (36.4±7.5) months, respectively, and the difference was not statistically significant (P=0.637). There was no statistically significant difference between the two groups in general data such as gender, age, and body mass index (all P>0.05), while there were statistically significant differences between the two groups in upper instrumented vertebrea (UIV) location and junctional area posterior ligamentous complex (PLC) injury (all P<0.05). The results of univariate analysis showed that UIV location at T10-T12, junctional area PLC injury, preoperative coronal thoracic curve (TC), preoperative and final follow-up PJA, and preoperative and final follow-up pelvic incidence-lumbarlordosis (PI-LL) were correlated with postoperative PJK (OR=2.50, 5.37, 0.92, 1.12, 1.32, 1.06, 3.35, all P<0.05). Multifactorial logistic regression analysis showed that UIV located at T10-T12 (OR=2.346, 95%CI: 1.582-3.481, P=0.001), junctional area PLC injury (OR=5.112, 95%CI: 1.283-20.418, P=0.023) and last follow-up PI-LL (OR=1.826, 95%CI: 1.558-24.745, P=0.012) were risk factors for the occurrence of postoperative PJK in children with Lenke type 5 AIS. Conclusions: Postoperative UIV fixation to the thoracolumbar segment, PLC injury in the junctional area and excessive postoperative PI-LL in children with Lenke type 5 AIS may be the risk factors for the occurrence of PJK after the operation. It is suggested that avoidance of UIV selection to the thoracolumbar segment, intraoperative protection of the PLC located near the UIV and restoration of a good PI-LL relationship may reduce the incidence of PJK.

Percutaneous Vertebroplasty and Upper Instrumented Vertebra Cement Augmentation Reducing Early Proximal Junctional Kyphosis and Failure Rate in Adult Spinal Deformity: Case Series and Literature Review.

One of the risks involved after long-segment fusions includes proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). There are reported modalities to help prevent this, including 2-level prophylactic vertebroplasty. In this study, our goal was to report the largest series of prophylactic cement augmentation with upper instrumented vertebra (UIV) + 1 vertebroplasty and a literature review. We retrospectively reviewed our long-segment fusions for adult spinal deformity from 2018 to 2022. The primary outcome measures included the incidence of PJK and PJF. Secondary outcomes included preoperative and postoperative Oswestry Disability Index, visual analog scale back and leg scores, surgical site infection, and plastic surgery closure assistance. In addition, we performed a literature review searching PubMed with a combination of the following words: "cement augmentation," "UIV + 1 vertebroplasty," "adjacent segment disease," and "prophylactic vertebroplasty." We found a total of 8 articles including 4 retrospective reviews, 2 prospective reviews, and 2 systematic reviews. The largest cohort of these articles included 39 patients with a PJK/PJF incidence of 28%/5%. Overall, we found 72 long-segment thoracolumbar fusion cases with prophylactic UIV cement augmentation with UIV + 1 vertebroplasty. The mean follow-up time was 17.25 months. Of these cases, 8 (11.1%) developed radiographic PJK and 3 (4.2%) required reoperation for PJF. Of the remaining 5 patients with radiographic PJK, 3 were clinically asymptomatic and treated conservatively and 2 had distal fractured rods that required only rod replacement. In this study, we report the largest series of patients with prophylactic percutaneous vertebroplasty and UIV cement augmentation with a low PJK and PJF incidence of 11.1% and 4.2%, respectively, compared with previously reported literature. Surgeons who regularly perform long-segment fusions for adult spinal deformity can consider this in their armamentarium when using methods to prevent adjacent segment disease because it is an effective modality in reducing early PJK and PJF that can often result in revision surgery.

The Relationship between the Hounsfield Units Value of the Upper Instrumented Vertebra and the Severity of Proximal Junctional Fracture after Adult Spinal Deformity Surgery.

Background and Objectives: In this retrospective cohort study, we investigate associations between the Hounsfield units (HU) value of upper instrumented vertebra (UIV) and proximal junctional kyphosis (PJK) after adult spinal deformity (ASD) surgery. Materials and Methods: The cohort consisted of 60 patients (mean age 71.7 years) who underwent long instrumented fusion surgery (≥6 vertebrae) for ASD with at least 1 year of follow-up. The preoperative bone mineral density (BMD) measured on DXA scans, the HU values at UIV and UIV+1, and the radiographic parameters were compared between the PJK and non-PJK groups. The severity of UIV fracture was assessed using a semiquantitative (SQ) grade. Results: PJK occurred in 43% of patients. No significant differences in patient age, sex, BMD, and preoperative radiographic parameters were observed between the PJK and non-PJK groups. The HU values of the UIV (103.4 vs. 149.0, p < 0.001) and UIV+1 (102.0 vs. 145.7, p < 0.001) were significantly lower in the PJK group. The cutoff values of HU at UIV and UIV+1 were 122.8 and 114.9, respectively. Lower HU values at UIV (Grade 1: 134.2, Grade 2: 109.6, Grade 3: 81.1, p < 0.001) and UIV+1 (Grade 1: 131.5, Grade 2: 107.1, Grade 3: 82.1, p < 0.001) were associated with severe SQ grade. Conclusions: Lower HU values at UIV and UIV+1 had a negative impact on signal incidence of PJK and were correlated with the severity of UIV fractures. Preoperative treatment of osteoporosis seems necessary for preoperative UIV HU values less than 120.

Use of multiple rods and proximal junctional kyphosis in adult spinal deformity surgery.

Multiple rods are utilized in adult spinal deformity (ASD) surgery to increase construct stiffness. However, the impact of multiple rods on proximal junctional kyphosis (PJK) is not well established. This study aimed to investigate the impact of multiple rods on PJK incidence in ASD patients. ASD patients from a prospective multicenter database with a minimum follow-up of 1 year were retrospectively reviewed. Clinical and radiographic data were collected preoperatively, at 6 weeks postoperatively, at 6 months postoperatively, at 1 year postoperatively, and at every subsequent year postoperatively. PJK was defined as a kyphotic increase of > 10° in the Cobb angle from the upper instrumented vertebra (UIV) to UIV+2 as compared with preoperative values. Demographic data, radiographic parameters, and PJK incidence were compared between the multirod and dual-rod patient cohorts. PJK-free survival analysis was performed using Cox regression to control for demographic characteristics, comorbidities, level of fusion, and radiographic parameters. Overall, 307/1300 (23.62%) cases utilized multiple rods. Cases with multiple rods were more likely to be revisions (68.4% vs 46.5%, p < 0.001), to be posterior only (80.7% vs 61.5%, p < 0.001), involve more levels of fusion (mean 11.73 vs 10.60, p < 0.001), and include 3-column osteotomy (42.9% vs 17.1%, p < 0.001). Patients with multiple rods also had greater preoperative pelvic retroversion (mean pelvic tilt 27.95° vs 23.58°, p < 0.001), greater thoracolumbar junction kyphosis (-15.9° vs -11.9°, p = 0.001), and more severe sagittal malalignment (C7-S1 sagittal vertical axis 99.76 mm vs 62.23 mm, p < 0.001), all of which corrected postoperatively. Patients with multiple rods had similar incidence rates of PJK (58.6% vs 58.1%) and revision surgery (13.0% vs 17.7%). The PJK-free survival analysis demonstrated equivalent PJK-free survival durations among the patients with multiple rods (HR 0.889, 95% CI 0.745-1.062, p = 0.195) after controlling for demographic and radiographic parameters. Further stratification based on implant metal type demonstrated noninferior PJK incidence rates with multiple rods in the titanium (57.1% vs 54.6%, p = 0.858), cobalt chrome (60.5% vs 58.7%, p = 0.646), and stainless steel (20% vs 63.7%, p = 0.008) cohorts. Multirod constructs for ASD are most frequently utilized in revision, long-level reconstructions with 3-column osteotomy. The use of multiple rods in ASD surgery does not result in an increased incidence of PJK and is not affected by rod metal type.

Surgical Treatment of Scoliosis Lenke Type 5, Anterior Versus Posterior, Which Approach is Better?: A Systematic Review and Meta-Analysis.

Systematic review and meta-analysis. This study aimed to compare the radiographical and clinical outcomes between anterior spinal fusion (ASF) and posterior spinal fusion (PSF) in Lenke type 5 adolescence idiopathic scoliosis. PSF has been the standard operation for adolescence idiopathic scoliosis. ASF can also achieve a good curve correction effect with fewer fusion segments and minor invasion of paraspinal structures. A systematic literature research was conducted in PubMed, Embase, Cochrane Library, and Web of Science. Use meta-analysis to compare the changes of thoracolumbar/lumbar and thoracic curves and other important outcomes between ASF and PSF. A total of 427 ASF and 392 PSF patients from 12 studies were included. There was no significant difference in the correction degree of thoracolumbar/lumbar and thoracic curve between ASF and PSF ( P >0.05), except for PSF had more compensatory correction degree of thoracic curve at postoperation ( P <0.05). Besides, the loss of correction in thoracic curve in PSF at the last follow-up was significantly less than that in ASF ( P <0.05). PSF presented larger change values of thoracic kyphosis and lumbar lordosis at the last follow-up ( P <0.05). PSF showed a better effect in correcting trunk shift distance at the postoperation ( P <0.05) but less trunk shift distance correction from postoperation to last follow-up ( P <0.05). There was no significant difference in the incidence of proximal junctional kyphosis and estimated blood loss between the two approaches ( P >0.05). Moreover, ASF showed fewer fusion segments, but longer operation and hospital stay time ( P <0.05). ASF is capable of achieving similar correction in coronal curve and balance as PSF with fewer fusion segments. Spine surgeons should select an appropriate approach tailored to individual patients needs while considering procedural risks and benefits. Level II.

Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis-The Spinous Processes and Proximal Rod Contouring.

Proximal junctional kyphosis (PJK), as one of the most discussed problems after corrective surgery in adolescent idiopathic scoliosis (AIS), is still not fully clarified and seems to be multifactorial. Biomechanical and a few clinical studies have shown the influence of destruction of posterior ligaments by resection of spinous processes and some parameters concerning rod contouring as risk factors for PJK. To verify these results, 192 patients with AIS and corrective surgery via a posterior approach between 2009 and 2017 were included. Radiographic parameters were analyzed preoperatively (preOP), postoperatively (postOP), and with a mean follow up (FU) of 27 months. The participants were divided into two groups (PJK group and non-PJK group). The incidence of PJK was 15.6%. Contrary to the results of biomechanical studies, we could not find any significant influence of the spinous process resection. However, the PJK group had significantly larger preOP T4–T12 kyphosis (31.1° ± 13.93° vs. 23.3° ± 14.93°, p = 0.016). Furthermore, the PJK group showed a significantly larger rod contour angle (RCA) (8.0° ± 4.44° vs. 5.9° ± 3.28°, p = 0.003) and mismatch of postOP proximal junctional angle (PJA) and RCA (3.5° ± 5.72° vs. 0.9° ± 4.86°, p = 0.010) compared to the non-PJK group. An increase in the mismatch of postOP PJA and RCA (OR = 1.14, p = 0.008) and a high RCA are risk factors for PJK and need to be focused on by surgeons.

The Impact of Upper Instrumented Vertebra Orientation on Proximal Junctional Kyphosis: A Novel and Fixed Parameter, Fused Spinopelvic Angle.

A retrospective study. To evaluate the impact of upper instrumented vertebra (UIV) orientation including the fused spinopelvic angle (FSPA) on proximal junctional kyphosis (PJK). PJK is a challenging complication after adult spinal deformity (ASD) surgery. Some studies proposed UIV orientation act as a risk factor of PJK, but there remain debates because UIV orientation is changed by position. Therefore, we investigated the relationship between the FSPA, a novel parameter for the relationship between UIV and pelvis which did not change by position, and PJK. ASD patients who underwent long-segment fusion to the pelvis and followed up for more than two years were included. Comparative analysis was performed on spinopelvic parameters including UIV orientation parameters (UIV slope angle and FSPA) between PJK and non-PJK group. Binary regression analysis was conducted to find out the risk factors for PJK. And correlation analysis was conducted to find out the parameters that affect the FSPA. A total of 190 patients were included. PJK incidence was 13.2% (25/190). PJK group showed a significantly greater postoperative UIV slope (21.3° vs. 18.8°, P =0.041) and significantly lesser postoperative FSPA (-0.9° vs. 4.5°, P <0.001). In binary regression analysis, only FSPA acted as a risk factor of PJK (odds ratio=0.920, P =0.004). The FSPA has strong positive correlation with pelvic incidence (PI)-lumbar lordosis (LL) ( r =0.666, P <0.001) and negative correlation with lordosis distribution index (LDI) ( r =-0.228, P =0.004). The FSPA is a fixed parameter which is not dependent on position. A reduction of the FSPA increases the risk for PJK. The FSPA can be adjusted through PI-LL and LDI. Thus, surgeons should increase the FSPA by adjusting the PI-LL and LDI during ASD surgery to prevent PJK.

Health-related quality of life outcomes in adolescent Scheuermann's kyphosis patients treated with posterior spinal fusion: A comparison with age- and sex-matched controls.

Purpose:To assess the health-related quality of life and radiographic outcomes of surgically treated adolescent Scheuermann’s kyphosis patients after minimum of 2-year follow-up and to compare the health-related quality of life with age- and sex-matched healthy controls.Methods:Twenty-two consecutive adolescents (mean age = 16.7 years) undergoing posterior spinal fusion for Scheuermann’s kyphosis were included and matched by age and sex with two healthy controls. The health-related quality of life was evaluated using the Scoliosis Research Society-24 questionnaire. Radiographic parameters were measured for comparison preoperatively and at 6 months and 2-year follow-ups. The health-related quality of life parameters were compared with healthy controls at 2 years of follow-up.Results:The mean maximal thoracic kyphosis improved from 79° (range = 75°–90°) to 55° (range = 45°–75°) (p < 0.001), and the mean lumbar lordosis was reduced from 71° (range = 51°–107°) to 52° (range = 34°–68°) (p < 0.001) after 2 years postoperatively. Incidence of proximal junctional kyphosis (PJK) was 18%. The scores of the Scoliosis Research Society-24 improved, with statistical significance observed in pain and self-image domains from preoperative to 2-year follow-up (p = 0.002 in both domains). The self-image and function were significantly lower in the operated patients at their 2-year follow-up visit compared to controls (p = 0.023 for self-image and p < 0.001 for function).Conclusion:Instrumented posterior spinal fusion improves the health-related quality of life of Scheuermann’s kyphosis patients during the 2-year follow-up. The greatest improvement is observed in pain and self-image domains. The health-related quality of life in pain and activity domains reaches the level of healthy individuals, while function and self-image remain at a statistically lower level.

Does pelvic incidence tell us the risk of proximal junctional kyphosis in adult spinal deformity surgery?

To investigate the relationship between pelvic incidence (PI) and proximal junctional kyphosis (PJK) in patients treated surgically for adult spinal deformity (ASD) with fusion from thoracolumbar junction to sacrum. A consecutive series of ASD patients who underwent fusion from the thoracolumbar junction to the sacrum with a minimum of 2-year follow-up was studied. Patients were divided into low PI (≤ 50°) and high PI (> 50°) groups. We compared radiographic parameters and the rates of PJK, between the two groups. A sub-analysis was performed on patients with a postoperative PI minus lumbar lordosis mismatch between - 10° and 10° (i.e., ideally corrected). Sixty-three patients were included: 19 low PI and 44 high PI. Median follow-up was 34months (range 24-103). Overall PJK rate was 38%. PJK was observed in 16% of low PI and 48% of high PI patients (p = 0.02). The odds ratio for developing PJK with a high PI compared to a low PI was 4.9 (p = 0.03). There were 32 ideally corrected patients. Eleven of these were in the low PI group, and 21 patients were in the high PI group. The incidence of PJK was 25% for ideally corrected patients. PJK occurred in none of these patients in the low PI group and 38% of patients in the high PI group (p = 0.03). When the upper-instrumented vertebra includes the thoracolumbar junction, patients with a PI > 50° are at a significantly higher risk of developing PJK compared to patients with a PI ≤ 50°.

Low-Density Pedicle Screw Constructs Are Associated with Lower Incidence of Proximal Junctional Failure in Adult Spinal Deformity Surgery.

Retrospective cohort study. Determine whether screws per level and rod material/diameter are associated with incidence of proximal junctional kyphosis (PJF). PJF is a common and particularly adverse complication of adult spinal deformity (ASD) surgery. There is evidence that the rigidity of posterior spinal constructs may impact risk of PJF. Patients with ASD and 2-year minimum follow-up were included. Only patients undergoing primary fusion of more than or equal to five levels with lower instrumented vertebrae (LIV) at the sacro-pelvis were included. Screws per level fused was analyzed with a cutoff of 1.8 (determined by receiver operating characteristic curve (ROC) analysis). Multivariable logistic regression was utilized, controlling for age, body mass index (BMI), 6-week postoperative change from baseline in lumbar lordosis, number of posterior levels fused, sex, Charlson comorbidity index, approach, osteotomy, upper instrumented vertebra (UIV), osteoporosis, preoperative TPA, and pedicle screw at the UIV (as opposed to hook, wire, etc.). In total, 504 patients were included. PJF occurred in 12.7%. The mean screws per level was 1.7, and 56.8% of patients had less than 1.8 screws per level. No differences were observed between low versus high screw density groups for T1-pelvic angle or magnitude of lordosis correction (both P > 0.15). PJF occurred in 17.0% versus 9.4% of patients with more than or equal to 1.8 versus less than 1.8 screws per level, respectively (P < 0.05). In multivariable analysis, patients with less than 1.8 screws per level exhibited lower odds of PJF (odds ratio (OR) 0.48, P < 0.05), and a continuous variable for screw density was significantly associated with PJF (OR 3.87 per 0.5 screws per level, P < 0.05). Rod material and diameter were not significantly associated with PJF (both P > 0.1). Among ASD patients undergoing long-segment primary fusion to the pelvis, the risk of PJF was lower among patients with less than 1.8 screws per level. This finding may be related to construct rigidity. Residual confounding by other patient and surgeon-specific characteristics may exist. Further biomechanical and clinical studies exploring this relationship are warranted.Level of Evidence: 3.