Correction Of Thoracolumbar Kyphosis Research Articles

Multilevel Pedicle Subtraction Osteotomy for Correction of Thoracolumbar Kyphosis in Ankylosing Spondylitis: Clinical Effect and Biomechanical Evaluation.

To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.

Risk Factors for Distal Junctional Problems Following Long Instrumented Fusion for Degenerative Lumbar Scoliosis: Are they Related to the Paraspinal Muscles.

Although the incidence of distal junctional problems (DJPs) following long construct-based treatment for degenerative lumbar scoliosis (DLS) is lower, affected patients are more likely to require revision surgery when they occur. So the aim of this study is to identify risk factors associated with DJPs to avoid its occurrence by at least 1-year follow-up. A total of 182 DLS patients undergoing long instrumented fusion surgery (≥4 levels) between February 2011 and March 2022 were retrospectively analyzed. Patients were placed into the DJP group if a DJP occurred at the final follow-up; patients without mechanical complications were matched 1:2 according to age, sex and BMI as the control group. Patient characteristics, surgical variables, radiographic parameters, lumbar muscularity and fatty degeneration were analyzed statistically. The statistical differences in the results between the two groups (p values <0.05) and other variables selected by experts were entered into a multivariate logistic regression model, and the forwards likelihood ratio method was used to analyze the independent risk factors for DJPs. Twenty-four (13.2%) patients suffered a DJP in the postoperative period and the reoperation rate was 8.8%. On univariate analysis, the lowest instrumented vertebra (LIV) CT value (p = 0.042); instrumented levels (p = 0.030); preoperative coronal vertical axis (CVA) (p = 0.046), thoracolumbar kyphosis (TLK) (p = 0.006), L4-S1 lordosis (p = 0.013), sacral slop (SS) (p = 0.030), pelvic tilt (PT) classification (p = 0.004), and sagittal vertical axis (SVA) (p = 0.021); TLK correction (p = 0.049); post-operative CVA (p = 0.029); Overall, There was no significant difference in the paraspinal muscle parameters between the two groups. On multivariate analysis, instrumented levels (OR = 1.595; p = 0.035), preoperative SVA (OR = 1.016; p = 0.022) and preoperative PT (OR = 0.873; p = 0.001) were identified as significant independent risk factors for DJP. Longer instrumented levels, a greater preoperative SVA and a smaller PT were found to be strongly associated with the presence of DJPs in patients treated for DLS. The degeneration of the paraspinal muscles may not be related to the occurrence of DJPs. For DLS patients, the occurrence of DJP can be reduced by selecting reasonable fusion segments and evaluating the patient's sagittal balance and spino-pelvic parameters before operation.

The Association Between Corrective Surgery for Adult Spinal Deformity and Serum Levels of Hepatobiliary Enzymes.

Background and objective The surgery to correct adult spinal deformity (ASD) is associated with a rare, but life-threatening complication called acute celiac artery compression syndrome (ACACS). To our knowledge, there is currently no study in the literature regarding the abnormal elevation of serum levels of hepatobiliary enzymes after surgery to correct the deformity. In light of this, the purpose of this study was to investigate this potential association. Materials and methods We collected data on 74 patients with ASD who underwent correction surgery at our institution. A Spearman's rank-order correlation was used to assess the association between serum levels of hepatobiliary enzymes and spinal parameters. Factors showing a correlation coefficient of 0.2 or more were combined in a stepwise multiple regression analysis. Results The mean age of the patientswas 68.4 ± 7.7 years; the study comprisedsix men and 68 women. In our stepwise multiple regression analysis, there were two valid models that included spinal parameters as independent variables: changes in lactate dehydrogenase (LDH) - changes in thoracolumbar kyphosis (TLK) (B -0.0025 ± 0.0007, p<0.01), and changes in LDH - preoperative T12-L1 kyphosis (B 0.0031 ± 0.001, p<0.01). Additionally, both valid models contained median arcuate ligament (MAL) overlap defined as MAL crossing the base of the celiac artery (CA) as a significant independent variable. Conclusions Greater sagittal correction of TLK, larger preoperative T12-L1 kyphosis, and MAL overlap were factors associated with an elevated serum level of LDH. Although few patients werereported to have clinically severe symptoms, "potential" ACACS due to a temporary blood flow disturbance can occur in this patient population.

Reoperation depending on time period following pedicle subtraction osteotomy for thoracolumbar kyphosis in patients with ankylosing spondylitis.

The aim of this study was to investigate time-dependent rates and indications of unplanned reoperation and to evaluate the most common indication depending on the time interval after pedicle subtraction osteotomy (PSO) for correction of thoracolumbar kyphosis in patients with ankylosing spondylitis (AS). A total of 321 consecutive patients with AS (284 men; mean age 43.8 years) with thoracolumbar kyphosis who underwent PSO were included. Patients who underwent reoperation after the index surgery were divided according to the duration of the follow-up period. A total of 51 patients (15.9%) underwent unplanned reoperations. The reoperation groups had greater preoperative and postoperative C7 sagittal vertical axis (SVA), and less lordotic postoperative osteotomy angle (-4.3° ± 18.6° vs -15.0° ± 13.7°, p < 0.001). The perioperative change in SVA was not significantly different between groups (-10.0 ± 7.1 cm vs -10.0 ± 5.1 cm, p = 0.970), while that in the osteotomy angle was significantly different (-22.4° ± 21.3° vs -30.0° ± 11.5°, p = 0.014). Most reoperations (45.1%; 23/51) were performed within 2 weeks of the initial operation. Within 2 weeks, the most common cause of reoperation was neurological deficit in 10 patients, with a cumulative reoperation rate of 3.2%. After 3 years, the most common complications were mechanical complications in 8 patients, accounting for 15.7% (8/51) of patients. Overall, the most common indications for reoperation were mechanical complications (17 patients; 5.3%), followed by neurological deficits (12 patients; 3.7%). PSO may be the most effective surgical procedure for the correction of thoracolumbar kyphosis in patients with AS. However, 51 patients (15.9%) required an unplanned reoperation.

Intraoperative pleural rent during kyphosis surgery: Monitor tells before surgeons!!

Dear Editor, Spine surgery is a complex surgery associated with complications even in the most experienced hands.[1] One of the known complications is intraoperative pleural injury especially with thoracic spine involvement.[2] We are reporting an intraoperative incident during thoracolumbar kyphosis correction surgery of a 13-year old female child (weighing 30 kg, 140 cm height) who underwent surgery involving fifth thoracic to second lumbar vertebral levels by posterior instrumentation. Kyphosis angle was 15° with no other systemic illness. After adequate fasting, child was shifted to OT and standard anesthesia monitors were attached. She was induced intravenously after securing an intravenous (i.v.) cannula and positioned prone after securing 6.5mm cuffed endotracheal tube. Initially during surgery, baseline ventilatory parameters were peak airway pressures of 18 to 19cm H2O and pulmonary compliance of 17ml/cm H2O. After 2 h of surgery, there was a sudden decrease in peak airway pressures (from 19 to 8cm H2O) and a marked increase in lung compliance (recorded in Dräger Primus anesthesia workstation) (from 17.2 to 48ml/cm H2O) [Figure 1a and b]. A fall in central venous pressure (CVP) from 9 to 5mmHg was noticed without significant blood loss and with adequate volume replacement [Figure 2a and b].Figure 1: Intraoperative trends of peak airway pressure and compliance (a) after repair of one-sided pleural rent with normalized parameters and (b) at the time of pleural rent on other side showing fall in airway pressures and increase in complianceFigure 2: Intraoperative central venous pressure (CVP) trends (a) after repair of one-sided pleural rent and (b) at the time of pleural rent on other side showing fall in CVPConsidering close proximity of surgical field to pleura and nature of event, we suspected pleural injury possibly pleural rents. The relationship between transmural pressure and lung’s volume is defined by compliance. Our lungs have an inherent tendency to collapse, whereas chest wall has tendency to expand. These two opposing forces create a negative intrapleural pressure. For lung expansion, positive transmural pressure is required (intra-alveolar pressure > intrapleural pressure).[3] The compliance curve is steeper at lower lung volumes and plateaus as volume increases meaning easier expansion of lung at lower lung volume when pulmonary compliance is high. This physiological phenomenon was clearly seen in our intraoperative findings. Fall in peak airway pressures and dramatically increased compliance. It normalised within a few minutes. [Figure 1a] picture after sealing of pleural rent. Again after a few minutes peak pressures dropped from 19 to 8cm H2O and lung compliance increased from 17.2 to 48ml/cm H2O [Figure 1b]. The operating surgeon figured out the cause and repaired the pleural rent bilaterally. Due to rent in pleura, there was a loss of intrapleural pressure and the lungs that have a tendency to collapse showed an increased compliance due to markedly decreased lung volume, which normalised after repair and similar thing happened on the other side, [Figure 1b]. A fall in CVP was also noticed due to fall in intrathoracic pressure to 5mmHg [Figure 2b], which returned to baseline (9mmHg) after pleural repair [Figure 2a]. Our case, had an open pneumothorax due to large pleural rent as opposed to tension pneumothorax associated to a ball-valve mechanism in literature.[4,5] Timely diagnosis and repair of pleural rent can prevent post-operative pneumothorax. Therefore, ventilatory parameters monitored by advanced anesthesia workstations can guide for early detection and immediate repair of large pleural rents even if it goes undetected by surgical team. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Junctional Failure After Thoracolumbar Kyphosis Correction in Patients with Ankylosing Spondylitis

We investigated the characteristics and revision rate of junctional failure after surgical correction for thoracolumbar kyphosis in patients with ankylosing spondylitis. A total of 230 patients had undergone surgical correction for thoracolumbar kyphosis from 2010 to 2019. The state of ankylosis between the uppermost instrumented vertebra (UIV) and UIV+1 and between the lowermost instrumented vertebra (LIV) and LIV-1 was analyzed using a modified Stoke ankylosing spondylitis spine score. Proximal junctional failure (PJF) and distal junctional failure (DJF) were defined as any type of symptomatic junctional failure. Of the 230 patients, 23 (10.0%) had developed junctional failure. Of these 23 patients, 16 had had partial ankylosis and 7 had had complete ankylosis. PJF had developed in 10 patients and DJF in 13. The most common type of junctional failure was a junctional fracture, which developed in 12 patients. PJF had developed by UIV fracture in 4 patients, UIV+1 fracture in 1 patient, and UIV+2 in 1 patient. DJF had developed by LIV fracture in 6 patients, metallic failure in 5, and progression of DJF in 2 patients. The average time to the development of PJF and DJF was 13 months and 12.4 months, respectively. All 10 patients with PJF and 7 of 13 patients with DJF (53.8%) had required reoperation. Of the 12 patients with junctional fracture, 11 (91.7%) had undergone reoperation. Of the 23 patients with junctional failure, 16 had had immature ossification of the anterior longitudinal ligament. Therefore, to prevent junctional failure, the state of ankylosis seems to be important for selecting the fusion level after osteotomy. Once junctional failure has developed, however, reoperation should be considered owing to the stress concentration at the UIV or LIV.

The contribution of pre-existing spinal pseudarthrosis to the surgical correction for thoracolumbar kyphosis secondary to ankylosing spondylitis

The correction of global kyphosis (GK) for ankylosing spondylitis (AS) patients with pre-existing pseudarthrosis were frequently over 45°. Mismatch between kyphosis correction of GK and pedicle subtraction osteotomy (PSO) may be ascribed to contribution of pseudarthrosis. The aim of the present study was to evaluate surgical outcomes of PSO away from the level of pseudarthrosis and to elucidate the contribution of pre-existing spinal pseudarthrosis in surgical correction of thoracolumbar kyphosis caused by AS. Eighteen AS patients with pre-existing pseudarthrosis were included. PSO outside the level of pseudarthrosis were performed for all the patients. The average follow-up period were 29 months. Radiographs were analyzed for correction and complications. Significant improvement in all sagittal parameters were found postoperatively without obvious correction loss at the final follow-up. Local kyphosis (LK) improved from 23.88° preoperatively to 12.67° postoperatively with a mean correction of 11.47°. Average correction of per PSO segment, GK and sum of disc wedging within fused region (SDW) were 33.53°, 49.27° and 4.00°, respectively. PSO away from the level of pseudarthrosis, but with posterior instrumentation crossing it was a feasible method and was able to maintain sustained surgical outcomes. Regarding GK correction, PSO accounted for 68.1% while pre-existing pseudarthrosis provided 23.3%, which resulted from anterior column opening postoperatively. Thus, extra kyphosis correction attributed to pre-existing pseudarthrosis should be considered for surgical-decision making to prevent overcorrection.

Improvement in functional gait parameters following corrective thoracolumbar surgery in children affected by Mucopolysaccharidosis 1 (Hurler syndrome)

ObjectiveThoracolumbar kyphosis is a common indication for spinal surgery in children with Mucopolysaccharidosis. Functional outcome of spinal surgical intervention has never been published in patients with this rare disease. We present a cohort of patients with Mucopolysaccharidosis 1(Hurler syndrome) who underwent thoraco-lumbar spinal deformity correction and functional outcome assessed by pre-operative and post-operative gait analysis. This study represents the first attempt at presenting a functional assessment of surgical outcome in any Mucopolysaccharidosis subtype.MethodsA retrospective analysis of prospectively collected data was carried out from 11 children diagnosed with this subtype of Mucopolysaccharidosis. All patients underwent thoracolumbar kyphosis correction between the years 2013 to 2016. Gait assessment was performed using GAITRite™ electronic walkway pre-operatively and post-operatively within 9 to 24 months from the index surgery. Walking distance, cadence and gait velocity were the three spatio-temporal parameters analysed. Wilcoxon signed rank test was used to analyse the data and P-Value ≤0.05 was deemed significant.ResultsThere was a statistically significant improvement in walking distance in 9 out of 11 patient post-operatively with a mean increase of 232.06 cms (P = 0.05). There was marginal improvement in cadence by 6.33 steps/min post-operatively (P-value 0.79). Gait velocity also showed a marginal increase by 8.73 cms/sec post-operatively (P-value 0.32).ConclusionThe results of our study suggest that correction of thoracolumbar kyphosis in children with Mucopolysaccharidosis 1 resulted in a significant improvement of walking distance with a trend towards improved gait in the other parameters. Post-operative change in cadence was not statistically significant suggesting that physiological maturation of gait had minimal effect in the specified post-operative assessment timeframe. This study emphasizes that outcomes of spinal surgery in children with Mucopolysaccharidosis 1 should be determined by functional measures aiming to maintain or improve quality of life.

Barriers of neurophysiology monitoring in spine surgery: Latin America experience.

Background: Intraoperative neurophysiological monitoring (IOM) has become valuable in spine surgery. Unfortunately, it is not always available in many spine centers, especially in developing countries. Our aim was to evaluate the accessibility and barriers to IOM in spine surgery in Latin America.Methods: We designed a questionnaire to evaluate the characteristics of surgeons and their opinions on the usefulness of IOM for different spine operations. The survey was sent to 9616 members and registered users of AO Spine Latin America (AOSLA) from August 1, 2019, to August 21, 2019. Major variables studied included nationality, years of experience, specialty (orthopedics or neurosurgery), level of complexity of the hospital, number of spine surgeries performed per year by the spine surgeon, the types of spinal pathologies commonly managed, and how important IOM was to the individual surgeon. General questions to evaluate use included accessibility, limitations of IOM usage, management of IOM changes, and the legal value of IOM. The results were analyzed and compared between neurosurgeon and orthopedics, level of surgeon experience, and country of origin.Results: Questionnaires were answered by 200 members of AOSLA from 16 different countries. The most common responses were obtained from orthopedic surgeons (62%), those with more than 10 years of practice (54%); majority of surgeons performed more than 50 spine surgeries per year (69%) and treated mainly spine degenerative diseases (76%). Most surgeons think that IOM has a real importance during surgeries (92%) and not just a legal value. Although surgeons mostly considered IOM essential to scoliosis surgery in adolescents (70%), thoracolumbar kyphosis correction (68%), and intramedullary tumors (68%), access to IOM was limited to 57% for economic reasons. Of interest, in 64% of cases, where IOM was available and significant change occurred, the actual operative procedures were significantly altered.Conclusion: Despite the fact that 68% of spine surgeons believe IOM to be indispensable for complex spine surgery, cost remains the main barrier to its use/availability in Latin America.

Radiographic findings for surgery-related complications after pedicle subtraction osteotomy for thoracolumbar kyphosis in 230 patients with ankylosing spondylitis.

The purpose of this study was to investigate the rate of and the risk factors for surgery-related complications demonstrated on radiography after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis in patients with ankylosing spondylitis (AS). The authors retrospectively reviewed the medical records of 230 consecutive patients with thoracolumbar kyphosis due to AS who had undergone 1-level PSO at a single institution in the period from 2010 to 2017. The causes of surgery-related complications were divided into two types: surgical/technical failure and mechanical failure. The patients consisted of 20 women and 210 men, with an average age of 43.4 years. The average follow-up period was 39.0 months. The preoperative sagittal vertical axis was 18.5 ± 69.3 cm, which improved to 4.9 ± 4.6 cm after PSO. Of the 77 patients (33.5%) who experienced minor or major surgery-related complications, 56 had complications related to surgical/technical failure (overall incidence 24.3%) and 21 had complications related to mechanical failure (overall incidence 9.1%). Fourteen patients (6.1%) underwent reoperation. However, among the 77 patients with complications, the rate of revision surgery was 18.2%. The most common radiological complications were as follows: sagittal translation in 24 patients, coronal imbalance in 20, under-correction in 8, delayed union in 8, and distal junctional failure and kyphosis in 8. The most common causes of reoperation were coronal imbalance in 4 patients, symptomatic malposition of pedicle screws in 3, and distal junctional failure in 3. Delayed union was statistically correlated with posterior sagittal translation (p = 0.007). PSO can provide acceptable radiographic outcomes for the correction of thoracolumbar kyphosis in patients with AS. However, a high incidence of surgery-related complications related to mechanical failure and surgical technique can develop. Thorough radiographic investigation before and during surgery is needed to determine whether complete ossification occurs along the anterior and posterior longitudinal ligaments of the spine.

Combined percutaneous and open instrumentation for thoracolumbar kyphosis correction by two-level pedicle subtraction osteotomy in ankylosing spondylitis

A long global thoracolumbar kyphosis is common in ankylosing spondylitis. Surgical correction of fixed sagittal malalignment by pedicle subtraction osteotomy (PSO) might improve disability and quality of life (QoL). Two-level osteotomies represent major procedures with a risk of hemorrhage. Combined open and minimal invasive surgery has not been described and might be considered. A 30-year-old female with ankylosing spondylitis was treated by golimumab and teriparatide. The treatment was stopped during pregnancy which led to vertebral compression fractures and kyphosis of 50° between T11 and L3. A PSO was planned at the kyphotic apex L2. The second PSO was planned at L4 according to the pelvic incidence of 56°, matching with a spinopelvic alignment Roussouly type 3. A derived full balance integrated method was used to calculate the amount of correction. During the first stage surgery, an open approach was performed from L1 to pelvis and combined with percutaneous cement-augmented instrumentation in already fused segments T5-T12, thus reducing perioperative morbidity. A stepwise approach including L2 PSO closure with temporary rods and L4 PSO with final instrumentation was used. Blood loss was estimated around 1100ml. The patient was able to walk on the second day after surgery. A secondary anterior fusion with LLI cages from L2 to L5 and an ALIF at L5-S1 were performed because of high non-ossified intervertebral disks to reduce the risk for nonunion and rod fractures. At 2-year follow-up, the patient's QoL had significantly improved and full spine radiographs showed stable normalized sagittal parameters. The combined open and percutaneous approach was feasible and might be considered as an alternative option to conventional open surgery when planning major deformity correction in ankylosing spondylitis.

A novel tissue separation method for determining upper trunk center of gravity in patients with thoracolumbar kyphosis using MIMICS

BackgroundIn the past, a variety of methods have been explored to determine the center of gravity or gravity line, such as the hanging method or force plate analysis. However, these methods possess limitations related to precise location of center of gravity. The aim of this study was to describe a tissue separation method to precisely calculate the center of gravity in upper trunk. MethodsTwenty post-operative patients with thoracolumbar kyphosis were retrospectively studied. Center of gravity models were computed: T1–T5 segment, T6–T10 segment and T1–T10 segment. The tissue separation method was used to calculate the center of gravity in each segment. A new center of gravity was composited from T1–T5 segment and T6–T10 segment by composition formula. Similarity and collinearity between center of gravity models was analyzed to verify the reliability of tissue separation method. Correlation between gravity line and theoretic hip axis was compared on pre- and post-operative radiographs to explore their potential application for surgical plan. FindingsComposited center of gravity had significant correlation and high similarity with center of gravity in T1–T10 segment. There was high collinearity between center of gravity points. The post-operative included angle between the gravity line and theoretic hip axis significantly decreased to nearly 0°. InterpretationThese findings demonstrate the MIMICS can reliably calculate the center of gravity in the upper trunk by a tissue separation method. The pre-operative included angle between the gravity line and theoretic hip axis was suggested as a parameter to improve surgical design for thoracolumbar kyphosis correction.

Comparison of loss of correction between PSO and VCD technique in treating thoracolumbar kyphosis secondary to ankylosing spondylitis, a minimum 2\u2009years follow-up

BackgroundPedicle subtraction osteotomy (PSO) and vertebral column decancellation (VCD) are frequently used methods for correction of thoracolumbar kyphosis resulting from ankylosing spondylitis (AS). However, there are limited reports performed to evaluate the difference of loss of correction and the effectiveness of PSO and VCD techniques in patients with thoracolumbar kyphosis secondary to AS.ObjectiveTo retrospectively estimate the effectiveness of correction and loss of correction of PSO and VCD techniques in patients with thoracolumbar kyphosis secondary to AS.MethodsWe performed a retrospective review of 61 consecutive AS kyphosis patients undergoing PSO or VCD surgery from March 2012 to April 2015. The patients were divided into PSO group (n = 25) and VCD group (n = 36) according to the types of osteotomies. Measurement of the radiographic parameters was performed and the change was analyzed.ResultsMean loss of correction in the global kyphosis was 2.31° in the PSO group and 2.29° in VCD group at the last follow-up, respectively, with no significant difference. Progressive junctional kyphosis occurred in both groups. VCD obtained a significantly larger correction than PSO while sharing a similar incidence of complications. No serious complications were observed in the two groups.ConclusionThe PSO osteotomy and VCD osteotomy are both safe and effective methods in treating thoracolumbar kyphosis secondary to AS. Mild loss of correction mainly occurred in the global kyphosis in both techniques with no significant difference.

Spontaneous Remodeling of Spinal Canal After Sagittal Translation in Pedicle Subtraction Osteotomy for Correction of Thoracolumbar Kyphosis in Ankylosing Spondylitis

Sagittal translations (STs) secondary to osteotomy for the correction of ankylosing spondylitis (AS) kyphosis have drawn great attention, which is considered closely related to neurologic deficits and terrible fusion. Despite being discussed in several cases, there were no relevant reports about the transformation of ST and the spinal canal remodeling in AS patients. Retrospective analysis was conducted on 16 patients with ST for the treatment of AS kyphosis through pedicle subtraction osteotomy during January 2011 to December 2014 in our hospital. Full-length free-standing spinal radiographs were available for all patients before and after surgery and also at the final follow-up. Radiologic parameters including global kyphosis (GK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sagittal vertical axis (SVA), and ST were measured. Rates of ST transformation after the surgery and at 1-year follow-up were compared. The average follow-up was 22 months, ranging from 12-36 months. There was no internal fixation failure during this period. The preoperative GK was 59.9 ±21.0°, TLK was 38.0 ± 13.0°, LL was 7.4 ± 26.5°, and SVA was 27.2 ± 8.6 mm. The postoperative GK was 15.7 ± 2.1°, TLK was 5.6 ± 2.6°, LL was-36.1 ± 2.9°, and SVA was 6.1 ± 4.3 mm. ST was 7.1 ± 2.7 mm after surgery and 1.2 ± 1.0 mm at 1-year follow-up. The difference was statistically significant (P < 0.05). The rate of ST transformation was 84.9% ± 9.7%. According to Scoliosis Research Society surveys, the preoperative and the final follow-up satisfaction score was 1.6±0.3 and 4.7 ± 0.4 respectively (P < 0.05). Remodeling of the spinal canal happened to all the patients with different degrees. All patients with ST after pedicle subtraction osteotomy for AS kyphosis occurred with spontaneous remodeling of the spinal canal at 1-year follow-up, by which ST can decrease in different degrees or even disappear, and favorable fusion can be achieved even without bone grafting into the osteotomy vertebra.

Sagittal Spinopelvic Parameters in Children With Achondroplasia

Study DesignRetrospective cross-sectional, longitudinal radiographic analysis. ObjectiveTo report the natural history of spinopelvic parameters in achondroplasia. Summary of Background DataSagittal spinal deformity is common in children with achondroplasia. However, few data exist on their normative spinal parameters. MethodsLateral standing spine radiographs of children with achondroplasia were reviewed. Measurements included thoracic kyphosis, lumbar lordosis (LL), thoracolumbar kyphosis (TLK), pelvic incidence (PI), T1 pelvic angle (TPA), and sagittal balance (SVA). Comparison between age groups and longitudinal analysis of children with minimum five-year radiographic evaluation was performed; evolution of radiographic measurements was assessed. Children who underwent surgical correction of TLK were studied separately to describe changes of sagittal spinal parameters associated with TLK surgical correction. ResultsIn cross-sectional analysis, 745 radiographs (282 children) were measured. During the first three years, TLK decreased and LL and sacral slope increased significantly. After age 3 years, TLK decreased gradually until age 10. Afterwards, TLK decrease became non-significant. PI increased gradually after age 10. In the longitudinal group, 81 children were followed an average of 8.7 (5–19) years between age 4.4 and 13.1 years. TLK decreased; LL and PI increased significantly. TPA and SVA remained within the normal range although changes with growth were statistically significant. In the surgical group, 19 children underwent surgical TLK correction. Apart from TLK correction, no sagittal parameters changed significantly after surgery. These 19 children had higher TLK and lower LL compared with a nonsurgical group at similar average age. ConclusionIn children with achondroplasia, TLK improvement occurs primarily before age 3 years; hyperlordosis at the lumbosacral level is the compensatory mechanism. Significant changes in the sagittal spinal parameters occur early in life, suggesting the importance of attention to sagittal malalignment to prevent any possible clinical sequelae of severe hyperlordosis. Level of EvidenceLevel III, prognostic study.

The Efficacy of Brace Treatment for Thoracolumbar Kyphosis in Patients With Achondroplasia.

A retrospective study. The aim of this study was to evaluate the outcome of brace treatment in the correction of thoracolumbar kyphosis (TLK) for patients with achondroplasia and to determine the factors associated with bracing efficacy. Brace treatment has been used to correct TLK in patients with achondroplasia. However, there was a paucity of knowledge concerning its effectiveness. A total of 33 achondroplasic patients treated by bracing were included in this study. Radiographic parameters including TLK, lumbar lordosis, curve magnitude, apical vertebral translation (AVT), percentage of apical vertebral wedging, pelvic tilt (PT), and pelvic incidence were recorded for each patient at the visit. Comparison of these parameters between the initial visit and the final visit was performed using the Student t test. Factors associated with the correction of TLK were evaluated using the logistic regression analysis. The mean age at presentation was 27.5 ± 13.4 months. The mean period of treatment was 32.2 ± 15.7 months, and the mean period of follow-up was 25.7 ± 11.3 months. At the initial visit, the mean value of TLK and the percentage of apical vertebral wedging were 41.7 ± 15.4° and 61.4% ± 16.2%, respectively. At the final visit, the TLK and apical vertebral wedging were remarkably reduced to 29.5 ± 20.8° and 52.1% ± 18.7%, respectively. The logistic regression analysis showed that initial TLK, AVT, percentage of apical vertebral wedging, and PT were independent factors associated with the correction of TLK. Brace treatment can effectively correct TLK and restore the morphology of apical vertebral body for patients with achondroplasia. Large TLK, severe apical vertebral wedging, presence of AVT, and low PT may be indicative of an unfavorable outcome, which should be taken into account at the initiation of bracing. 4.

Does the preoperative lumbar sagittal profile affect the selection of osteotomy level in pedicle subtraction osteotomy for thoracolumbar kyphosis secondary to ankylosing spondylitis?

ObjectiveTo investigate the different preoperative lumbar sagittal profiles of ankylosing spondylitis (AS) patients and the selection of osteotomy level for one-level pedicle subtraction osteotomy (PSO) for the correction of thoracolumbar kyphosis. Patients and methodsSeventy-one consecutive AS patients with an average age of 35.3 years and a mean follow-up time of 35.9 months who underwent one-level PSO for thoracolumbar kyphosis were divided into 2 groups based on their preoperative lumbar sagittal profiles as follows: group A, lordotic lumbar sagittal profiles; and group B, kyphotic lumbar sagittal profiles. The following radiological parameters were measured and compared: chin-brow vertical angle (CBVA), global kyphosis (GK), thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). Clinical evaluation included Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS). Perioperative and mid-term complications were reviewed. ResultsThere were 28 patients in group A and 43 in group B. The preoperative LL was −21.0° in group A and 2.3° in group B (P < 0.05). The preoperative SVA was 122.5 mm in group A and 184.3 mm in group B (P < 0.05). All the patients in group A (100%) underwent PSO at L1/L2, while 90% of group B patients underwent PSO at L2/L3, with no significant difference of postoperative GK, LL and SVA between the 2 groups (P > 0.05). No obvious loss of correction was observed in either group at the final follow-up. The correction of LL and SVA showed a strong but not statistically significant increasing trend as the PSO level descended from L1 to L3 (P > 0.05). The postoperative ODI was significantly lower in patients underwent PSO at L1 or L2 (P < 0.05). ConclusionsPatients in group B had significantly worse preoperative sagittal alignments compared to group A. The distribution of osteotomy levels varied between the 2 groups due to the different lumbar profiles; however, satisfactory correction was achieved in both groups. The preoperative lumbar profiles need to be considered in selecting the optimal osteotomy level. Patients with kyphotic lumbar profiles are suitable candidates for PSO at L2/L3, while L1/L2 PSO is appropriate for patients with lordotic lumbar profiles.

Analysis of the Risk Factors for Unfavorable Radiologic Outcomes after Fusion Surgery in Thoracolumbar Burst Fracture : What Amount of Postoperative Thoracolumbar Kyphosis Correction is Reasonable?

ObjectiveThe aims in the management of thoracolumbar spinal fractures are not only to restore vertebral column stability, but also to obtain acceptable alignment of the thoracolumbar junction (T-L junction) to prevent complications. However, insufficient surgical correction of the thoracolumbar spine would be likely to cause late progression of abnormal kyphosis. Therefore, we identified the surgical factors that affected unfavorable radiologic outcomes of the thoracolumbar spine after surgery. MethodsThis study was conducted in a single institution from January 2007 to December 2013. A total of 98 patients with unstable thoracolumbar spine fracture were included. In these patients, fixation was done through transpedicular screws with rods by three surgical patterns. We reviewed digital radiographs and analyzed the images preoperatively and postoperatively during follow-up visits to compare the change of the thoracolumbar Cobb angle with radiologic parameters and clinical outcomes. The unfavorable radiologic group was defined as the patients who were measured as having greater than 20 degrees of thoracolumbar Cobb angle on the last follow-up, or who underwent kyphotic progression of thoracolumbar Cobb angle greater than 10 degrees from the immediate postoperative state to final follow-up, or who had overt instrument failure with/without additional surgery. We assessed the risk factors that affected the unfavorable radiologic outcomes. ResultsWe had 43 patients with unfavorable radiologic outcomes, including 35 abnormal thoracolumbar alignments and 14 instrumental failures with/without additional surgery. The multivariate logistic regression test showed that immediate postoperative T-L junction Cobb angle less than 10.5 degrees was a statistically significant risk factor, as well as the presence of osteoporosis (p=0.017 and 0.049, respectively). ConclusionInsufficient correction of thoracolumbar kyphosis was considered to be a major factor of an unfavorable radiological outcome. The spinal surgeon should consider that having a T-L junction Cobb angle larger than 10.5 degrees immediately after surgery could result in an unfavorable radiological outcome, which is related to a poor clinical outcome.

Prevalence and key radiographic spinal malalignment parameters that influence the risk for gastroesophageal reflux disease in patients treated surgically for adult spinal deformity

BackgroundGastroesophageal reflux disease (GERD) is a factor that has a significant negative impact on the quality of life (QoL). Vertebral fractures and/or spinal malalignment may influence the frequency of GERD. However, the epidemiology and pathology of GERD in patients with adult spinal deformity (ASD) are still largely unknown. To establish the optimal surgical strategy for GERD in patients treated surgically for ASD, we sought to clarify the GERD prevalence, determine radiographically which spinal malalignment parameters influence GERD risk, and evaluate GERD improvement postoperatively.MethodsSeventy-one consecutive patients with ASD who were treated with thoracolumbar corrective surgery and followed up for at least 1 year were enrolled. GERD was diagnosed by a gastroenterologist based on proton pump inhibitor medication response and/or an FSSG score > 8 points. Full-length lateral radiographs in a standing posture and in a supine, fulcrum backward-bending (FBB) position were taken preoperatively and 1 year postoperatively, and radiographic parameters were obtained. Correlations between radiographic parameters and FSSG scores were determined by Pearson’s correlation coefficient. Multivariate logistic regression analyses were performed to evaluate the odds ratio (OR) with a 95% confidence interval (95% CI) for potential risk factors for GERD.ResultsPatients were classified into two groups based on GERD symptoms, with 37 (52%) in the GERD+ group. Thoracolumbar kyphosis (TLK) in the FBB position was significantly more common in the GERD+ versus the GERD− group. Multivariate logistic regression analysis showed that lumbar lordosis (LL) and TLK curve in the FBB position significantly influenced the presence of GERD. Other factors showed no association with GERD. Significant improvements in FSSG scores were noted 1 year postoperatively. However, 20 (28.2%) patients still had GERD symptoms. The postoperative TLK curve was highly significantly correlated with FSSG scores 1 year postsurgery.ConclusionsOf the 71 patients treated surgically for ASD, 37 (52%) had a high frequency of GERD symptoms. An inflexible thoracolumbar curve with increased TLK in the FBB position was significantly associated with GERD symptoms. Despite significant improvements in FSSG scores postoperatively, insufficient correction of TLK might be a risk factor for persistent GERD symptoms.

Does the Traversing Length of the Aorta Change After Closing Wedge Osteotomy for Ankylosing Spondylitis Patients With Thoracolumbar Kyphosis?: A Magnetic Resonance Imaging Investigation.

A prospective magnetic resonance imaging (MRI) study. To investigate the change in aortic traversing length in patients with thoracolumbar kyphosis secondary to ankylosing spondylitis (AS) after closing wedge osteotomy (CWO). The CWO has been widely adopted for the correction of thoracolumbar kyphosis caused by AS. During this procedure, the aorta may be elongated in the instrumented area, which implies a potential risk of the aortic injury. To date, no reports have been specifically published using MRI to investigate the alteration in aortic traversing length in patients with AS undergoing CWO. From June 2013 to July 2015, 24 patients with AS with thoracolumbar kyphosis with a mean age of 38.1 years were recruited in the present study. All patients underwent single-level CWO. MRI examinations were performed before and 2 weeks after surgery. For each subject, the aortic diameter and length were measured on the MRI. Radiographic measurements included the global kyphosis, thoracic kyphosis, lumbar lordosis, local kyhosis, angle of fusion levels, and anterior height of the osteotomized vertebra. The height of these patients was also recorded. The aortic traversing length significantly increased by an average of 2.0 cm after surgery. Significant changes in height, global kyphosis, lumbar lordosis, local kyphosis, and angle of fusion levels were observed (P < 0.01), whereas the anterior height of the osteotomized vertebra was comparable before and after surgery (P > 0.05). In addition, the correlation analysis revealed a significant correlation between the aortic traversing length and changes in global kyphosis, lumbar lordosis, local kyphosis, angle of fusion levels, and height (P < 0.01). The stretch of the aorta after CWO for the correction of thoracolumbar kyphosis was quantitatively verified by MRI investigation in the present study. Spine surgeons should be aware of the potential vulnerability of aortic injury in patients with AS undergoing CWO. 4.