Sagittal Imbalance Research Articles

Anterior column realignment better restores sagittal alignment but carries higher risk of mechanical failures than lateral lumbar interbody fusion in patients with degenerative sagittal imbalance

Background of contextAnterior column realignment (ACR), a modified lateral lumbar interbody fusion (LLIF), is an emerging, less invasive technique that allows greater lordosis correction by releasing anterior longitudinal ligament. However, long-term results have been poorly documented with regard to mechanical failure, such as proximal junctional kyphosis (PJK) and rod fracture (RF), and clinical outcomes. PurposeTo compare the outcomes, primarily mechanical failure, in patients with degenerative sagittal imbalance (DSI) treated with ACR versus LLIF alone. Study design/settingRetrospective study Patient samplePatients ≥ 60 years of age; severe DSI defined by pelvic incidence (PI) - lumbar lordosis (LL) ≥ 20°; performance of ≥ 2-level LLIF; and ≥ 5 total fused levels including the sacrum. Outcome measuresMechanical failure such as PJK and RF; radiographic results; clinical outcomes MethodsEnrolled patients were divided into two groups, based on whether their anterior reconstruction was accomplished with ACR or LLIF alone: ACR and LLIF groups. Mechanical failures were compared between the two groups as a composite outcome including PJK and /or RF. PJK was defined as proximal junctional angle (PJA) >28° and Δ PJA >22°. Only RFs developing at the level with corresponding procedures (ACR or LLIF) were included in the analysis. Logistic regression was performed to compare the relative risk of mechanical failure between the ACR and LLIF groups. The radiographic and clinical outcomes were also compared between the groups. ResultsThe final study cohort consisted of 210 patients. The mean age was 69.6 years, and there were 190 females (90.5%). There were 124 patients in the ACR group and 86 patients in the LLIF group. Perioperative changes for all sagittal parameters were significantly greater in the ACR group than in the LLIF group. Overall mechanical failure rates were significantly higher in the ACR group than in the LLIF group (32.3% vs. 14.0%, P = 0.003). Multivariate regression analysis with adjusting potential confounders revealed that ACR carried a significantly higher risk of mechanical failure than LLIF (Odds ratio = 5.6, 95% confidence interval = 2.0 – 15.6, P < 0.001). The final clinical outcomes were worse in the ACR group than in the LLIF group. ConclusionACR restored the sagittal malalignment more powerfully than did LLIF. However, compared to the LLIF, ACR was associated with a greater risk of mechanical failures and revision surgery. The final clinical outcomes in the ACR group were inferior to those in the LLIF group. Therefore, ACR should be left as a last resort for the cases where it is expected that an adequate correction cannot be achieved using LLIF alone. If ACR has to be performed, it is necessary to establish feasible surgical strategies to avoid mechanical failures.

Biportal Endoscopic Lumbar Ponte Osteotomy for Kyphosis: A Technical Note

Biportal endoscopic lumbar Ponte osteotomy (BELPO) is an innovative technique for correcting kyphotic deformities. Unlike the original technique, which maintains an intact anterior column, BELPO involves the endoscopic release of the anterior elements in addition to the endoscopic resection of the posterior elements in interbody fusion. BELPO is performed using unilateral biportal endoscopy with the patient in a prone position. First, a small incision is made in the midline over the interspinous gap. Through this gap, a generous portion of the spinous processes and interspinous ligament is removed. Using this incision as both the viewing and working portal, complete facetectomy and partial laminectomy are performed. Posterior compression is then applied to achieve the desired lordosis. Pedicle screws are fixed with cement augmentation. A 71-year-old female patient presented with low back pain and positive sagittal imbalance. She had a rigid posttraumatic kyphosis at L2–3 due to an old compression fracture at L3. After BELPO, the kyphosis at L2–3 improved from 21º to 2º. BELPO is a promising novel method of minimally invasive deformity correction, offering particular advantages for frail, osteoporotic patients.

Sagittal Realignment Following Decompression for Lumbar Spinal Stenosis in Elderly Patients: A Comprehensive EOS Imaging Analysis.

This study investigated whether decompression surgery for lumbar spinal stenosis can effectively improve sagittal alignment in elderly patients. With the growing focus on sagittal balance in spinal surgery, this study aimed to evaluate post-decompression alignment changes and identify the factors influencing these changes using the EOS imaging system. A retrospective analysis was conducted on 49 elderly patients who underwent decompression surgery alone for lumbar spinal stenosis. Radiologic parameters, measured using the EOS system, and clinical outcomes were assessed preoperatively, at two weeks postoperatively, and at one year postoperatively. Patients were grouped based on the improvement of the sagittal vertical axis (SVA) by 25 mm or more. A multivariate analysis was performed to identify factors affecting sagittal alignment changes. Significant sagittal alignment improvements were observed postoperatively, including a notable increase in thoracic kyphosis and a decrease in SVA observed at one year. Clinical outcomes, such as the Oswestry disability index (ODI) and EQ-5D, significantly improved at both two weeks and one year postoperatively compared to preoperative values (all p-values < 0.05). Multivariate analysis revealed that greater preoperative SVA and higher ODI were significant predictors of sagittal alignment changes (odds ratio [OR] for SVA = 1.014, OR for ODI = 1.034). Decompression surgery for lumbar spinal stenosis in elderly patients can result in significant improvements in sagittal alignment and clinical outcomes. The study suggests that decompression alone is a viable surgical option for elderly patients, particularly those with a greater preoperative sagittal imbalance and disability, even in the absence of major deformities.

Paraspinal muscle fibre structural and contractile characteristics demonstrate distinct irregularities in patients with spinal degeneration and deformity.

Paraspinal and spinopelvic muscular dysfunction are hypothesized to be a causative factor for spinal degeneration and deformity; however, our fundamental understanding of paraspinal muscle (dys)function remains limited. Twelve surgical patients with spinal degeneration were recruited and categorized into group DEG (four patients) with no sagittal imbalance and no usage of compensatory mechanisms; group DEG-COMP (four patients) with no sagittal imbalance through use of compensatory mechanisms; and group DEG-COMP-UNBAL (four patients) with sagittal imbalance despite use of compensatory mechanisms. From each patient, four biopsies were collected from right and left multifidus (MULT) and longissimus (LONG) for single fibre contractile and structural measurements. Eight of 48 (17%) biopsies did not exhibit any contractile properties. Specific force was not different between groups for the MULT (p = 0.47) but was greater in group DEG compared to group DEG-COMP-UNBAL for the LONG (p = 0.02). Force sarcomere-length properties were unusually variable both within and amongst patients in all groups. Thin filament (actin) lengths were in general shorter and more variable than published norms for human muscle. This study is the first to show a heightened intrinsic contractile muscle disorder (i.e. impaired specific force generation)in patients with spinal degeneration who are sagittally imbalanced (compared to patients without deformity). Additionally, there are clear indications that patients with spinal degeneration (all groups) have intrinsic force sarcomere-length properties that are dysregulated. This provides important insight into the pathophysiology of muscle weakness in this patient group.

A Comparative Study on the Consistency of Ultrasound and X-Ray in Assessing Risser Sign.

Adolescent idiopathic scoliosis (AIS) is a 3-dimensional spinal deformity involving lateral curvature, sagittal plane imbalance, and vertebral rotation. In China, AIS affects over 3 million individuals, with 300,000 new cases annually. AIS impacts physical and psychological well-being, necessitating tailored treatment plans based on growth risk factors. This study evaluates the consistency of ultrasound and X-ray assessments of the Risser sign in AIS patients and explores correlations between iliac crest distance and pelvic rotation degree. This prospective study enrolled 80 patients diagnosed with AIS from June to September 2023 at Changzhou Sports Hospital. Eligible participants were aged 10-18 with a Cobb angle >10°. Ultrasonographic examinations were conducted by 3 experienced physicians using the VINNO V10 portable ultrasound system. The primary outcome was the Risser stage determined by X-ray and ultrasound, with secondary outcomes including thoracic and thoracic-lumbar segment rotation angles. Statistical analyses included kappa statistics, correlation analyses, and multiple regression. Among the 77 valid cases, 154 iliac wings were evaluated, with a high concordance rate of 77% between ultrasound and X-ray assessments. kappa values for left and right iliac crests were 0.723 and 0.808, respectively. Grouping Risser grades (0-1, 2-3, and 4-5) into 3 categories yielded kappa values of 0.93, 0.96, and 0.93, indicating high consistency. Significant correlations were found between iliac crest distances and rotation angles (left iliac crest distance and left thoracic rotation angle, r = 0.56, P < .001; right iliac crest distance and right thoracic-lumbar rotation angle, r = 0.69, P < .001; right iliac crest distance and right thoracic rotation angle, r = 0.39, P < .01). Ultrasound is a reliable, radiation-free alternative to X-ray for assessing the Risser sign in AIS patients. Despite observed inconsistencies in intermediate Risser grades, ultrasound's ability to reduce radiation exposure and provide consistent results makes it a valuable tool in clinical practice. Further research is needed to optimize ultrasound techniques and explore its potential for early detection and intervention in scoliosis management.

Comparison of Patients with and without Predicted Surgical Indication between Clusters of Adult Spine Deformity (ASD) Patients.

Multicentric, retrospective analysis of prospectively collected data. To utilize machine-learning (ML) for clustering and management prediction (conservative vs. operative) in surgically treated adult spine deformity (ASD) patients, and to compare the attainment of the Minimum Clinically Important Difference (MCID) between predicted surgical and conservative patients. Management choice in ASD is complex. ML can identity patient clusters and predicted treatment, but it is unclear whether patients treated according to the prediction also show better clinical outcomes. ASD patients (2-year follow-up) were divided into groups using k-means clustering. Management choice was predicted among operated patients in each cluster. The MCID for the Oswestry Disability Index (ODI) and the Scoliosis Research Society-22 (SRS-22) was calculated and compared between patients with and without surgical prediction. In Cluster 1 (idiopathic scoliosis, n=675, 150 surgeries), 57% of patients had a conservative prediction. Of these, 52% and 49% achieved MCID for ODI and SRS-22, respectively, compared to 68% and 75% for those with surgical predictions (OR=2 and 3.1, respectively).In Cluster 2 (moderate sagittal imbalance, n=561, 200 surgeries), 12% had a conservative prediction. Of these, 29% and 46% achieved MCID for ODI and SRS-22, respectively, compared to 47% and 56% for those with surgical predictions.In Cluster 3 (significant sagittal imbalance, n=537, 197 surgeries), 17% had a conservative prediction. Of these, 12% and 15% achieved MCID for ODI and SRS-22, respectively, compared to 37% and 45% for those with surgical predictions (OR=4.2 and 4.5, respectively). Patients with a concordant surgical prediction and management had higher odds of achieving the MCID, indicating a good correlation between prediction and clinical outcomes. In Cluster 3, the low percentage of patients with conservative prediction achieving the MCID suggests that machine learning could well identify patients with poor clinical outcomes.

Effect of growth hormone to spinal growth and recombinant human growth hormone to scoliosis.

Growth hormone (GH) plays a key role in human growth and development. In addition to promoting height growth, GH affects bone metabolism, bone size, and bone mineral density (BMD) in children and adolescents by affecting bone formation and resorption. Among them, the effect of GH on spinal growth has been widely concerned. Scoliosis is a three-dimensional structural spinal deformity characterized by lateral curvature of one or more segments of the spine accompanied by vertebral rotation and sagittal imbalance. For children with growth hormone deficiency (GHD), whether GH supplementation leads to scoliosis is still controversial. In recent years, numerous scholars have conducted extensive research to investigate the correlation between recombinant human GH replacement therapy and scoliosis, yielding divergent findings with some even presenting contradictory results. This study aims to investigate the impact of GH on spinal growth and explore the association between recombinant human GH replacement therapy and scoliosis by comprehensively reviewing the effects of GH and insulin-like growth factors 1 (IGF-1) on bone metabolism, bone mass, as well as examining the consequences of GHD on bone health. Additionally, we aim to access the influence of recombinant human GH replacement therapy on adolescent idiopathic scoliosis (AIS).

Is multilevel MIS-TLIF with bilateral facetectomy a lordosing procedure? A retrospective cohort of 3-level MIS-TLIF.

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a common surgery that has been extensively reported. However, publications on 3-level MIS-TLIF are sparse, and the effects of multilevel MIS-TLIF on sagittal balance remain controversial. This study aimed to analyze the outcomes and variables involved in the correction of sagittal imbalance by multilevel MIS-TLIF. Consecutive patients who underwent 3-level MIS-TLIF were retrospectively analyzed. Demographics and clinical outcomes were evaluated. Standard radiological and spinopelvic parameters were measured pre- and postoperatively, and at the last follow-up. A linear regression model was used to examine the correlation between preoperative segmental lordosis (SL) and the degree of sagittal correction. An optimal cutoff of preoperative SL to predict the change in sagittal correction was determined by receiver operating characteristic (ROC) analysis. Forty-seven patients (mean follow-up 24.63 ± 12.69 months) were included. Postoperatively, all patients showed clinical improvements, demonstrated by the Oswestry Disability Index and visual analog scale. The overall SL at the last follow-up was slightly nonsignificantly increased (1.23°, p = 0.267), while the other spinopelvic parameters, including lumbar lordosis (p = 0.008), sacral slope (p < 0.001), pelvic tilt (p = 0.002), and pelvic incidence-lumbar lordosis mismatch (p = 0.006), all improved significantly compared with preoperatively. The preoperative SL was negatively correlated with the change in SL at the last follow-up (r2 = 0.2591, p = 0.0003), and the cutoff value was 26.89° (area under the ROC curve = 0.7836, p = 0.0087). The 24 patients who had a less lordotic lumbar spine (i.e., preoperative SL ≤ 27°) demonstrated significant improvement in spinopelvic parameters, whereas the other 23 patients (SL > 27°) had a slight, insignificant decrease of spinopelvic parameters. Multilevel MIS-TLIF improved sagittal balance and SL with satisfactory patient-reported clinical outcomes at 2 years postoperatively. Multilevel MIS-TLIF was more effective in increasing lordosis in patients whose lumbar spine had a smaller preoperative lordotic curve (SL ≤ 27°).

Prone Single Position Approach to Lateral Lumbar Interbody Fusion: Systematic Review and Meta-Analysis.

Lateral lumbar interbody fusion (LLIF) with posterior screw fusion is a safe and effective treatment for patients suffering from degenerative spine disorders. While LLIF has been shown to restore disc height, decompress neural components, correct sagittal imbalances, and improve pain scores, the approach requires repositioning patients for posterior pedicle fixation, which requires 2 separate surgeries. The evolution of surgical techniques, navigation, and robotics has allowed for a single position approach to LLIF with the patient in the prone position. The purpose of this study was to perform a systematic review and meta-analysis comparing the prone single position (PSP) LLIF approach to the dual position LLIF approach. We hypothesized that PSP LLIF will have a reduced operative time, complication rate, and blood loss compared with the dual position LLIF procedure. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. PubMed and Embase databases were searched with key terms: (lateral AND [interbody OR "inter body"] AND lumbar AND fusion) AND (prone OR single). Results were extracted and reviewed by 2 authors (MR and RB) per selection criteria. Patient demographics were extracted from the selected studies, along with surgical, patient-reported, and radiographic outcomes. A meta-analysis was performed using an unstandardized mean difference or log odds ratio with a confidence level of 95%. Fifteen studies were included in the systematic review and 5 studies compared PSP LLIF to dual position LLIF for meta-analysis. PSP LLIF had a reduced operative time and length of stay compared with the dual position approach, although there was no significant reduction in estimated blood loss. Additionally, PSP LLIF improved lumbar lordosis more effectively than dual position LLIF. There was no difference in segmental lordosis or pelvic tilt. There was no difference in intraoperative complications, postoperative complications, or reoperations. PSP LLIF reduces operative time and length of stay, with no relative increase in complications or reoperations compared with the dual position approach. Additionally, PSP LLIF improves lumbar lordosis relative to dual position LLIF, which may improve functional outcomes and reduce the risk of developing adjacent segment disease. The associated operative and postoperative benefits of PSP LLIF may improve long-term outcomes of patients undergoing spinal fusion.

Posture, balance and gait in axial spondyloarthritis: a case-control study.

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease that primarily involves the axial skeleton but may also present with peripheral joint involvement and extra-articular involvement. The present study aims to quantitatively analyze posture, balance, and gait parameters in patients with axSpA and and assess associated factors. This cross-sectional case-control study included 51 axSpA patients (30 males, 21 females; mean age 40.94 ± 10.48 years) and 51 age- and sex-matched healthy controls. In patients with axSpA, the Ankylosing Spondylitis Disease Activity Score CRP, the Bath Ankylosing Spondylitis Disease Activity Index(BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), the Bath Ankylosing Spondylitis Metrology Index(BASMI), the Maastrich Ankylosing Spondylitis Enthesitis Score(MASES), and the Ankylosing Spondylitis Quality of Life(ASQoL) scale were used. For postural analysis, DIERS formetric (Diers GmbH, Schlangenbad, Germany) videoraster- stereography device was utilized. HUR SmartBalance BTG4 (HUR-labs Oy, Kokkola, Finland) balance platform was used for postural balance and limit of stability (LOS) measurement. Participants were evaluated using Berg Balance Scale (BBS), Functional Reach Test (FRT) and Timed Up and Go Test (TUG). The Zebris FDM type 3 (Zebris Medical GmbH, Germany) walking platform was used to measure the spatiotemporal parameters of the participants. Comparison of postural parameters showed that sagittal imbalance and cervical depth distance were increased in the axSpA group than in the healthy participants (p < 0.004). Comparison of functional balance parameters showed that BBS and FRT scores were significantly lower (p < 0.001) in the axSpA group than in the control group, while TUG scores were significantly higher (p < 0.001). The LOS values, which evaluate dynamic balance were significantly lower, indicating impairment, in the axSpA group. In the measurement of postural sway, which indicates static balance, all 23 subparameters were found to be similar. When analyzing the spatiotemporal gait parameters, in the axSpA group compared with those in the control group; Foot angles (p= 0.028) and stride width (p = 0.004) were increased, whereas step lengths (p = 0.004) and stride lengths (P = 0.004) were decreased. In the axSpA group the gait speed was decreased (p = 0.004). When axSpA was analyzed separately as radiographic and nonradiographic axSpA, similar findings were observed in posture, balance, and gait parameters. No significant difference was observed. We found that the clinical assessments most closely associated with posture, balance, and gait analyses were BBS, FRT, TUG, and BASFI.

Analysis of Risk Factors Associated with Proximal Junctional Kyphosis Following Long Instrumented Fusion from L1 to Sacrum: Age Itself Does Not Independently Increase the Risk.

Background and Objectives: This study is a retrospective analysis aimed at understanding the incidence and risk factors of proximal junctional kyphosis (PJK) following long-instrumented spinal fusion from L1 to the sacrum in patients with mild to moderate sagittal imbalance. Materials and Methods: It recruited consecutive patients undergoing instrumented fusion from L1 to the sacrum for degenerative lumbar disease between June 2006 and November 2019 in a single institution. The patients' preoperative clinical data, muscle status at T12-L1 on magnetic resonance images, and sagittal spinopelvic parameters were analyzed. Univariate analysis was used to compare clinical and radiographic data between PJK and non-PJK patients. Logistic regression analysis was used to investigate the independent risk factors for PJK. Results: A total of 56 patients were included in this study. The mean age at surgery was 67.3 years and mean follow-up period was 37.3 months. In total, 10 were male and 46 were female. PJK developed in 23 (41.1%) out of 56; of these patients, 20 (87.0%) developed PJK within 1 year postoperatively. In the univariate analysis between PJK and non-PJK patients, the PJK group showed more frequent osteoporosis, lower body mass index, smaller cross-sectional area (CSA) and more fat infiltration (FI) in erector spinae muscle at T12-L1 and larger preoperative TLK and PT with statistical significance (p < 0.05). In the logistic regression analysis, severe (>50%) FI in erector spinae muscle (OR = 43.60, CI 4.10-463.06, R2N = 0.730, p = 0.002) and osteoporosis (OR = 20.49, CI 1.58-264.99, R2N = 0.730, p = 0.021) were statistically significant. Conclusions: Preexisting severe (>50%) fat infiltration in the erector spinae muscle and osteoporosis were independent risk factors associated with PJK following instrumented fusion from L1 to the sacrum, but age was not a risk factor.

WITHDRAWN: Using machine learning for clustering the IMU data of patients with sagittal imbalance of the spine

WITHDRAWN: Using machine learning for clustering the IMU data of patients with sagittal imbalance of the spine

WITHDRAWN: Predicting outcomes of sagittal imbalance of the spine surgery using IMU data and unsupervised models

WITHDRAWN: Predicting outcomes of sagittal imbalance of the spine surgery using IMU data and unsupervised models

Anterior Column Release: With Great Lordosis Comes Great Risk of Complications-A Case Series.

Retrospective review. We sought to characterize complications associated with anterior column release (ACR). Correction of positive sagittal imbalance was traditionally completed with anterior column grafts or posterior osteotomies. ACR is a minimally invasive technique for addressing sagittal plane deformity by restoring lumbar lordosis. We conducted a retrospective review of consecutive patients who underwent ACR in a prospectively kept database at a tertiary care academic center from January 2012 to December 2018. The prespecified complications were hardware failure (rod fracture, hardware loosening, or screw fracture), proximal junctional kyphosis, ipsilateral thigh numbness, ipsilateral femoral nerve weakness, arterial injury requiring blood transfusion, bowel injury, and abdominal pseudohernia. Thirty-eight patients were identified. Thirty-five patients had ACR at L3-4, 1 had ACR at L4-5, and 1 patient had ACR at L2-3 and L3-4. Eighteen patients (47.4%) had one of the prespecified complications (10 patients had multiple). Ten patients developed hardware failure (26.3%); 8 patients (21.1%) had rod fracture, 4 (10.5%) had screw fracture, and 1 (2.6%) had screw loosening. At discharge, rates of ipsilateral thigh numbness (37.8%) and hip flexor (37.8%)/quadriceps weakness (29.7%) were the highest. At follow-up, 6 patients (16.2%) had ipsilateral anterolateral thigh numbness, 5 (13.5%) suffered from ipsilateral hip flexion weakness, and 3 patients (5.4%) from ipsilateral quadriceps weakness. Arterial injury occurred in 1 patient (2.7%). Abdominal pseudohernia occurred in 1 patient (2.7%). There were no bowel injuries observed. ACR is associated with a higher than initially anticipated risk of neurological complications, hardware failure, and proximal junctional kyphosis.

Addressing sagittal plane imbalance in primary total knee arthroplasty.

Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies. In 137 robotic-assisted TKAs, extension and flexion stressed gap laxities and bone resections were measured. The primary outcome was the proportion and magnitude of medial and lateral SPI (gap differential > 2.0 mm) for KA, MA, and FA. Secondary outcomes were the proportion of knees with severe (> 4.0 mm) SPI, and resection thicknesses for each technique, with KA as reference. FA showed significantly lower rates of medial and lateral SPI (2.9% and 2.2%) compared to KA (45.3%; p < 0.001, and 25.5%; p < 0.001) and compared to MA (52.6%; p < 0.001 and 29.9%; p < 0.001). There was no difference in medial and lateral SPI between KA and MA (p = 0.228 and p = 0.417, respectively). FA showed significantly lower rates of severe medial and lateral SPI (0 and 0%) compared to KA (8.0%; p < 0.001 and 7.3%; p = 0.001) and compared to MA (10.2%; p < 0.001 and 4.4%; p = 0.013). There was no difference in severe medial and lateral SPI between KA and MA (p = 0.527 and p = 0.307, respectively). MA resulted in thinner resections than KA in medial extension (mean difference (MD) 1.4 mm, SD 1.9; p < 0.001), medial flexion (MD 1.5 mm, SD 1.8; p < 0.001), and lateral extension (MD 1.1 mm, SD 1.9; p < 0.001). FA resulted in thinner resections than KA in medial extension (MD 1.6 mm, SD 1.4; p < 0.001) and lateral extension (MD 2.0 mm, SD 1.6; p < 0.001), but in thicker medial flexion resections (MD 0.8 mm, SD 1.4; p < 0.001). Mechanical and kinematic alignment (measured resection techniques) result in high rates of SPI. Pre-resection angular and translational adjustments with functional alignment, with typically smaller distal than posterior femoral resection, address this issue.

Effect of Paravertebral Muscle Degeneration on Lumbar and Pelvic Sagittal Alignment in Patients With Degenerative Scoliosis.

Retrospective study. To explore the relationship between lumbar spine muscle mass and lumbar pelvic sagittal parameters in patients with degenerative scoliosis. This study included ADS patients who were treated in our hospital from 2019 to 2023. The spinal parameters were evaluated through X-rays, and the relative muscle volume (RMV) and fat infiltration (FI) were measured through three-dimensional reconstruction. Patients were categorized into 3 groups based on SRS-Schwab sagittal balance correction (0, +, ++), and into 3 groups based on GAP score (proportioned, moderately dis-proportioned, severely dis-proportioned). Finally, patients were classified into low-quality and high-quality groups based on the FI of Paraspinal muscles (PSM). The study included a total of 63 patients. Significant statistical differences were observed in the FI and RMV of MF, ES and PS among patients classified by SRS-Schwab PT classification. Additionally, significant statistical differences were found in the RMV of MF and PS among patients classified by SRS-Schwab PI-LL classification and GAP score. Furthermore, a significant correlation was found between the FI and RMV of PSM and lumbopelvic sagittal parameters. The ordinal regression model analysis revealed that FI of ES significantly impacted PT imbalance, while RMV of MF significantly impacted PI-LL imbalance. Moreover, significant differences were noted in PT and PI between the low-quality and high-quality multifidus groups. As sagittal imbalance worsens, PSM degeneration also intensifies, primarily characterized by an increase in FI and a decrease in RMV. Notably, PT and PI-LL are positively correlated with RMV and negatively correlated with FI.

In Reply: The Role of Pelvic Compensation in Sagittal Balance and Imbalance: The Impact of Pelvic Compensation on Spinal Alignment and Clinical Outcomes After Adult Spinal Deformity Surgery.

In Reply: The Role of Pelvic Compensation in Sagittal Balance and Imbalance: The Impact of Pelvic Compensation on Spinal Alignment and Clinical Outcomes After Adult Spinal Deformity Surgery.

Letter: The Role of Pelvic Compensation in Sagittal Balance and Imbalance: The Impact of Pelvic Compensation on Spinal Alignment and Clinical Outcomes After Adult Spinal Deformity Surgery.

Letter: The Role of Pelvic Compensation in Sagittal Balance and Imbalance: The Impact of Pelvic Compensation on Spinal Alignment and Clinical Outcomes After Adult Spinal Deformity Surgery.

[Translated article] Osteoporotic vertebral fractures: Natural history and impact

Osteoporosis, and the consequences derived from it, such as fragility fractures, constitute a growing public health problem. Suffering from a fracture of this nature is the main risk factor for suffering a new fracture.It is documented that vertebral compression fractures lead to significant morbidity and mortality, in the short and long term, as well as other complications, such as sagittal imbalance and hyperkyphosis of the segment. However, we have not found documentation that analyzes the medium and long-term consequences of these injuries, assessing the type of treatment used, and the economic impact they represent.The purpose of this review is to analyse the main recent literature on the subject and make a breakdown of the consequences of these fractures in various spheres, such as economic, quality of life, sagittal balance and radiographic parameters, pain or mortality; as well as a brief analysis of epidemiology and natural history. ConclusionOsteoporotic fractures constitute an emerging problem, both in the medical and economic fields. The consequences and sequelae on the patient are multiple and although surgical options offer good long-term results, it is necessary to properly select the patient, through multidisciplinary teams, to try to minimise potential complications.

Sequential correction of sagittal vertical alignment and lumbar lordosis in adult flatback deformity

BackgroundFlatback deformity, or lumbar hypolordosis, can cause sagittal imbalance, causing back pain, fatigue, and functional limitation. Surgical correction through osteotomies and interbody fusion techniques can restore sagittal balance and relieve pain. This study investigated sagittal vertical alignment (SVA) and lumbar lordosis correction achieved through sequential procedures on human spine specimens. MethodsHuman T10-sacrum specimens were stratified into 2 groups: degenerative flatback specimens had smaller L1-S1 lordosis compared to the iatrogenic group (26.1°±15.0° vs. 47.8°±19.3°, p<.05). Specimens were mounted in the apparatus in simulated standing posture with a nominal sacral slope of 45 degrees and subjected to a 400N compressive follower preload. Sequential correction of degenerative lumbar flatback deformity involved: anterior lumbar interbody fusion (ALIF) at L5-S1, ALIF at L4-5, lateral lumbar interbody fusion (LLIF) at L2-3 and L3-4, and posterior column osteotomy (PCO) at L2-3 and L3-4. In iatrogenic specimens, flatback deformity was created by performing a posterior in-situ immobilization using pedicle screw instrumentation at L4-L5-S1 followed by distraction across the pedicle screws. We then performed LLIF at L2-3 and L3-4, followed by PCO at L2-3 and L3-4. ResultsStatistically significant incremental corrections were noted in SVAs and lordosis after L5-S1 ALIF, L4-5 ALIF, and PCO in degenerative flatback specimens. For the iatrogenic group, statistically significant worsening was noted in measures of standing alignment after L4-L5-S1 hypolordotic fusion. Subsequent LLIF at L2-3 and L3-4 did not significantly improve sagittal alignment. However, after PCO at L2-3 and L3-4, final alignment parameters were not significantly different than preoperative baseline values prior to hypolordotic fusion. ConclusionsALIF cages in the lower lumbar segments significantly improved sagittal alignment in degenerative flatback specimens. In the upper lumbar segments, LLIF cages alone were ineffective at enhancing lumbar lordosis. LLIF cages in conjunction with PCO improved alignment parameters in degenerative and iatrogenic flatback deformities.