Spinal Sagittal Balance Research Articles

Surgical management of ossification of the posterior longitudinal ligament in the cervical spine

OPLL is a progressive process that can result in spinal cord compression and myelopathy. Various surgical approaches for the management of OPLL in the cervical spine exist. Our goal is to present our institution’s experience in the management of OPLL over the last 20 years. Sixty-eight patients underwent surgery for cervical OPLL. Mean age at surgery was 56.9 years. No differences between demographic characteristics and surgical approach were identified. There were no significant differences between the approaches regarding the mean estimated blood loss, occurrence of durotomy, reoperation rate, positive K-line and preoperative cervical spine sagittal balance. Number of levels operated on was significantly different (anterior approach 2 ± 0.8 levels, posterior approach 4.3 ± 1.3 levels, combined approach 3.3 ± 0.9 levels, p-value <0.01), but postoperative sagittal balance was not (anterior approach Cobb angle 11.9 ± 5.8 degrees, posterior approach Cobb angle 7 ± 3.5 degrees, combined approach Cobb angle 16.7 ± 7.3 degrees, p-value = 0.09). Functional outcomes were good for 70% of patients and did not significantly differ across approaches (anterior approach 28%, posterior approach 33%, combined approach 9%, p-value = 0.46). Good functional outcomes were more commonly observed in patients with a positive K-line (OR 0.2, 95% CI 0.04–0.9, p-value 0.05) while poor outcomes were most commonly observed in patients with an occupational ratio >0.6 (OR 6.9, 95% CI 1.35–42.7, p-value 0.02). OPLL is a rare disease for which prompt referral for surgical decompression may lead to good clinical outcomes.

Spinal sagittal balance associated with age, vertebral fracture, and functional disability in patients with rheumatoid arthritis: A cross-sectional study

Objectives: The purpose of this study was to assess the relationships between spinal sagittal balance and functional ability of Japanese patients with rheumatoid arthritis.Methods: A total of 491 patients with rheumatoid arthritis who underwent the measurement of sagittal vertical axis for the assessment of spinal sagittal balance were enrolled. Factors associated with sagittal vertical axis were analyzed by categorizing patients according to sagittal vertical axis (<4 cm, 4–9.5 cm, and >9.5 cm). In addition, univariate and multivariate regression analysis were performed to identify factors associated with Health Assessment Questionnaire Disability Index (HAQ-DI) in different age groups.Results: The percentage of patients with sagittal vertical axis <4 cm, 4–9.5 cm, and >9.5 cm was 61.1%, 32.4%, and 6.5%, respectively. Age, vertebral fracture, and gait speed were associated with sagittal vertical axis. Sagittal vertical axis was associated with HAQ-DI in the 80–90 years age group.Conclusion: Sagittal balance was associated with age, vertebral fracture, and gait speed. In super-aged patients with rheumatoid arthritis, HAQ-DI was affected by sagittal balance. Management of super-aged patients with rheumatoid arthritis should include evaluation of joints as well as spinal alignment.

Correlation between Forward Head Posture and Spinal Sagittal Balance

Abstract Background: Forward head posture and other forms of spinal sagittal imbalance at nowadays are a major cause of pain and disability among patients presenting to the spine clinic in daily practice. However, it is unclear if there are correlation between forward head posture and whole spinal balance or no therefore, the purpose of this study was to investigate the correlation between FHP and spinal sagittal balance. Aim of Study: This current study was planned to measure the correlation between FHP and spinal sagittal balance. Material and Methods: This study was carried at El-Sheikh Zayed Specialized Hospital out patient clinic of Physical Therapy. From December 2017 to April 2019. 30 subject aged between 25-35 years old from both sexes with radiological CVA <70' are included in this study, standard full-length lateral radiographs performed in all participant. FHP was assisted by CVA and we assess C7 plumb line for total spinal balance, Co-C2 angle for upper cervical lordosis, C2-C7 (SVA) and C2-C7 angle for lower cervical lordosis, T1 sagittal tilt, T4-T12 angle for thorathic kyphosis, L1-S1 angle for lumber lordosis and Sacral Slope (SS). Correlation analysis was used to identify the direction and strength of the relationship between forward head posture and spinal sagittal balance variables. Results: Forward head posture angle is negatively strong correlated to C2-C7 SVA and has a negative intermediate correlation with T1 tilting and C0-C2 angle but it has aweak positive correlation with C7-S 1 SVA, on the other hand it has an no correlation with C2-C7 angle, sacral slope, lumber lordosis and thoracic kyphosis. Conclusion: Increasing in forward head posture angle leads to increase in C7-S1 SVA and decrease in C2-C7 SVA, T1 tilting and C0-C2 angle. While it has no effect on C2-C7 angle, sacral slope, lumber lordosis and thoracic kyphosis.

Relationship between lumbopelvic discordance and locomotive syndrome in a middle-aged community-living population: The Yakumo study

BackgroundLocomotive syndrome (LS) affects the quality and activities of daily living. Although spinal sagittal balance influences LS, no report elucidated the relationship between LS risk and lumbopelvic discordance. This study aimed to investigate the relationship between lumbopelvic discordance and LS in a middle-aged community. MethodsThe subjects (n = 135) were divided into three groups based on the LS risk stage, which was evaluated through spinopelvic sagittal alignment and lumbopelvic mismatch prevalence (Pelvic incidence-Lumbar lordosis >10°:PI-LL mismatch).Then, the subjects were divided into two groups (lumbopelvic matched and mismatched groups) and analyzed based on the demographic data, physical test, stabilometry, and body pain using the visual analog scale. ResultsThere were 76, 37 and 22 subjects in stages 0, 1, and 2, respectively. The pelvic incidence-lumbar lordosis (PI-LL) mismatched group had a higher prevalence in LS risk stage 2 than in LS risk stage 0. The prevalence of PI-LL mismatch was significantly different among the groups. Post hoc test revealed the differences in spinopelvic alignment among the stages. In each LS risk stage, the degree of PI-LL was significantly higher in stage 2 than that in stages 0 and 1. On comparing the PI-LL matched (n = 67) and mismatched groups (n = 68) with a stabilometer, the envelopment area tracing by the movement of the center of pressure and locus length/second was greater in the PI-LL mismatched group than that in the PI-LL matched group with/without eyes opened. ConclusionsThe prevalence of LS risk stage 2 was more frequently observed in the PI-LL mismatched group. The degree of PI-LL was evaluated through the LS risk stages. Physical dysfunction in the PI-LL mismatched group was related to trunk imbalance based on stabilometry. These findings will help manage LS and PI-LL mismatched subjects.

The Effect of Straight or Lordotic Rods on Cervical Subaxial Alignment While Fusing C1-C2

The C1 lateral mass and C2 pedicle screw with rod fixation system has been used commonly in recent years. Despite the numerous reports on this technique in the literature, there are no studies regarding the effect of the angle of the rod used. We investigated the effect of rod angle on subaxial lordosis, cervical sagittal balance, and pain scores. Clinical records and radiologic images of 58 patients who underwent procedures between 2011 and 2016 at our clinic were assessed retrospectively. We recorded clinical findings, visual analog scale (VAS) scores, angles of cervical and segmental lordosis, and the distance between the C2 sagittal vertical axis (SVA) and the C7 posterior-superior corner. A total of 36 male and 22 female patients were enrolled. A negative correlation was found between the C1-C2 lordosis angle and the C2-C7 lordosis angle irrespective of surgical technique. In patients who were operated on using 30°-angled rods, there was a postoperative increase in C1-C2 lordosis degree and an improvement in C2 cervical SVA values. Postoperative month 6 VAS scores were significantly better in the patients who were operated on with angled rods compared with those who received straight rods. We believe this is because of the positive effect of the angled rod on sagittal balance. Nevertheless, prospective case-control studies should be conducted with larger groups of subjects. Furthermore, every patient should be evaluated considering the whole spinal sagittal balance.

Relationships between Spinal Sarcopenia and Spinal Sagittal Balance in Older Women

BackgroundSpinal sarcopenia is receiving renewed attention as a cause of spinal sagittal imbalance. However, the relationships between spinal sarcopenia and spinal sagittal balance (SSB) have not been thoroughly investigated. We evaluated the relationships between SSB parameters and sarcopenic indices with lumbar paraspinal muscle (LPM) quantity and strength in healthy older adults.MethodsTwenty-four healthy community-dwelling older women were enrolled. Demographic variables, conventional sarcopenic indices, isometric back muscle strength, and SSB parameters, as well as results of functional examinations and lumbar spine computed tomography scan with LPM cross-sectional area (CSA) and density assessments, were examined. The independent effect on the sum of the total LPM CSA was determined using multivariable regression analysis adjusted for age, appendicular skeletal muscle mass, gait speed, handgrip strength, back extensor strength, and pelvic tilt (PT) angle.ResultsPT angle was significantly correlated with the sum of the total LPM CSA and mean LPM density (r=-0.502, p=0.015 and r=0.504, p=0.014, respectively). Furthermore, PT angle was an independent factor for the sum of the total LPM CSA (β=-0.610, p=0.021) in the multivariate regression models (R2=0.320).ConclusionOur data suggest that PT angle was significantly correlated with LPM CSA in healthy older women. To our knowledge, this is the first report to investigate the relationships of sarcopenic indices and spinal muscle degeneration with SSB.

Natural aging course of paraspinal muscle and back extensor strength in community-dwelling older adults (sarcopenia of spine, SarcoSpine): a prospective cohort study protocol

IntroductionSarcopenia in the lumbar paraspinal muscles is receiving renewed attention as a cause of spinal degeneration. However, there are few studies on the precise concept and diagnostic criteria for spinal...

Биомеханические аспекты сагиттального баланса позвоночника у больных с коксартрозом при эндопротезировании (предварительное исследование)

The purpose of the study was to evaluate specific features of spine sagittal balance in patients with coxarthrosis of different etiology before and after total hip replacement (THR). Materials and methods Clinical and radiographic evaluation was performed for 46 patients admitted for primary THR. The patients were diagnosed with dysplastic (n = 14), degenerative (n = 26) and posttraumatic (n = 6) coxarthrosis and evaluated preoperatively, on the 7th day postsurgery and at a long-term follow-up. Spinopelvic parameters of sagittal balance, stages of osteoarthritis and cranial displacement of femoral heads according to Crowe were assessed. Clinical evaluation included physical examination, hip function with the Harris Hip Score (HHS), range of motion in the involved hip, relative limb shortening, neurological status, Oswestry questionnaire (ODI) and spinal pain syndrome using the Wong-Baker Faces Pain Rating Scale (2011). A statistical software package of Microsoft Office Excel 2016 was applied for data analysis. Statistical analysis of variance was used to calculate the arithmetic mean (M), error of the arithmetic mean (± m), the Pearson correlation coefficient r and estimate using the Chaddock scale. The Student’s t-test was used to confirm significant differences in the means identifying a significance level. Results and discussion Comparative analysis of spinopelvic parameters showed decreased PT and SS with increased LL in patients with dysplastic coxarthrosis. No considerable changes of spinopelvic parameters were revealed in patients with degenerative coxarthrosis. Marked limitations in ROM were seen in patients with dysplastic coxarthrosis. A moderate correlation between ROM of the involved hip and spinopelvic parameters was observed in dysplastic coxarthrosis. No correlation was detected between spinopelvic balance and spinal pain syndrome. Conclusion No significant differences in spinopelvic parameters were noted in patients with hip-spine syndrome associated with degeneration. Dysplastic changes can be a predisposing factor for spinopelvic imbalance in THR. Correlation analysis showed that combined joint contracture was involved into the biomechanical aspect of spinopelvic imbalance in dysplastic coxarthrosis. As reported by other researchers, total hip replacement with good functional outcome was not shown to result in significant changes in spinopelvic alignment.

A novel method for prediction of postoperative global sagittal alignment based on full-body musculoskeletal modeling and posture optimization

Associations between spinal sagittal balance and pain and disability are well documented. Reciprocal changes after spinal surgery might be critical for the outcomes, but assessing their extent remains a challenge. This paper proposes a method for predicting full-body sagittal alignment including reciprocal changes in response to spinal fusion, based on musculoskeletal modeling and inverse-inverse dynamics approach. An established body model (AnyBody) was used, with fused segments modeled as rigid. Posture was optimized based on muscle expenditure minimization, following the concept of the cone of economy. The data of adult spinal fusion patients were obtained retrospectively from an ongoing clinical study. Patient spino-pelvic alignment, body weight and height, age- and pathology-related muscle deterioration, and underwent treatment details were represented in the model. Predicted postural changes were compared to follow-up radiographs to evaluate method validity. Twenty-one cases were analyzed in this preliminary study (age range = 48–74; number of fused segments 1–14). The model predictions correlated well with the radiographic measures at follow-up: TPA, r = 0.83; ΔPILL, r = 0.90; LL, r = 0.90; TK, r = 0.77. The model demonstrated high accuracy in predicting sagittal imbalance (positive predictive value = 1.00, negative predictive value = 0.75). The presented method for patient- and treatment-specific postoperative posture prediction can be used to guide preoperative planning of spinal fusion, but more extensive validation is needed.

How reproducible do we stand and sit? Indications for a reliable sagittal spinal assessment

BackgroundCurrently, an upright standing posture is normally adopted for evaluations of spinal alignment, which is however sensitive to posture variations. Thus, finding a reproducible reference is essential. This study aimed to evaluate the reproducibility of standing and sitting postures at different arm positions in five consecutive repetitions. Methods22 asymptomatic subjects (11 males; 11 females) aged 20–35 years were included. Subjects were repeatedly asked to adopt different arm positions in standing and sitting. The absolute reposition errors of lumbar lordosis and sacral orientation between two consecutive repetitions were assessed with a non-radiological back measurement system. FindingsDuring standing at the relaxed arm position, the median absolute reposition errors of lumbar lordosis and sacral orientation were 1.14° (range 0.23°–3.80°) and 0.92° (range 0.17°–3.27°), respectively, which increased to 1.75° (range 0.21–4.97°) and 1.36° (range 0.35°–4.08°) during sitting (P < 0.01). The absolute reposition error of lumbar lordosis was non-significantly lower at the relaxed and clasped arm positions than at other arm positions. Between the first two repetitions, the absolute reposition errors of both, lumbar lordosis and sacral orientation, were greater than between the remaining two consecutive repetitions (P < 0.01). Both during standing and sitting, lumbar lordosis was smallest when hands holding two bars (P < 0.05). InterpretationSitting showed a worse reproducibility than standing. When assessing sagittal spinal balance, the clasped arm position during standing is recommended and an initial trial can help to reduce inception irreproducibility.

166. Can C7 slope be used as a substitute for T1 slope? A radiographic analysis

166. Can C7 slope be used as a substitute for T1 slope? A radiographic analysis

Sagittal balance of the spine

The static sagittal balance of the normal spine is a physiological alignment of the spine in the most efficient manner by the muscular forces. During gait, this balance is constantly thwarted by single-foot support. This analysis involves the study of parameters which are now well defined. The pelvic incidence is constant, and the sacral slope and the pelvic tilt are positional. The cervical parameters are the upper (O–C2) and lower cervical curvatures (C2–C7), the C7 slope, the spino-cranial angle and the vertical cervical offset. At the thoracic and lumbar level, they are, respectively, kyphosis and lordosis. The OD-HA (odontoid hip axis) angle is the most efficient parameter to analyse the global balance. The average values of these parameters are reported with the new 3D measurements by Le Huec et al. The relationship between these different parameters was analysed, and Roussouly proposed his classification of the different spine shape. Ageing makes it possible to show compensation mechanisms at three levels: spinal, pelvic and lower limbs. Understanding these different data allows for better planning of the surgical management of the patients. Global evaluation of the entire spine and the measurement of the aforementioned parameters allow to determine the extent of the correction to be performed during surgery. Taking these parameters into account also enables us to understand the complications involved in this type of surgery: transitional syndromes or junctional syndromes. Integration of these parameters into the study of gait is an area still under investigation.Graphic abstractThese slides can be retrieved under Electronic Supplementary Material .

Can C7 Slope Be Used as a Substitute for T1 Slope? A Radiographic Analysis.

Study Design:Retrospective radiographic study.Objectives:T1 slope is an important parameter of sagittal spinal balance. However, the T1 superior endplate can be difficult to visualize on radiographs due to overlying anatomical structures. C7 slope has been proposed as a potential substitute for T1 slope when the T1 superior endplate is not well visualized. The objective of this study was 2-fold: (1) to assess the correlation between C7 and T1 slopes on upright cervical spine radiographs and (2) to evaluate the interrater reliability of C7 slope.Methods:Cervical spine radiographs taken between December 2017 and June 2018 at a single institution were reviewed. Two observers measured upper C7 slope, lower C7 slope, and T1 slope. The correlations between upper and lower C7 slope and T1 slope were evaluated, and linear regression analyses were performed. Interrater reliability of C7 slope was also assessed.Results:In this cohort of 152 patients, there was a strong correlation between upper C7 slope and T1 slope (r = 0.91, P < .001), as well as between lower C7 slope and T1 slope (r = 0.90, P < .001). T1 slope could be estimated from the linear regression equation, T1 slope = 0.87 × C7 slope + 7, with an overall model fit of R 2 = 0.8. There was strong interrater reliability for upper (intraclass correlation coefficient [ICC] = 0.95, P < .001) and lower C7 slope (ICC = 0.96, P < .001).Conclusions:Both the upper and lower C7 slope are strongly correlated with T1 slope and can be used as a substitute to estimate T1 slope when the superior endplate of T1 is not well visualized.

ISSLS PRIZE IN CLINICAL SCIENCE 2019: clinical importance of trunk muscle mass for low back pain, spinal balance, and quality of life-a multicenter cross-sectional study.

A multicenter cross-sectional study. To clarify the relationship of trunk muscle mass with low back pain, spinal sagittal balance, and quality of life. Few reports have investigated the relationship of trunk muscle mass with lumbar spine function and spinal balance, and the clinical significance of trunk muscle mass remains unclear. Patients attending spinal outpatient clinics at 10 different medical institutions were enrolled in this study. Patient demographics, trunk muscle mass and appendicular skeletal muscle mass (ASM) measured by bioelectrical impedance analysis (BIA), body mass index (BMI), Charlson Comorbidity Index (CCI), the Oswestry Disability Index (ODI), visual analog scale (VAS) for low back pain, sagittal vertical axis (SVA), and EuroQol 5 Dimension (EQ5D) score were investigated. Multivariate nonlinear regression analysis was used to investigate the association of trunk muscle mass with the ODI, VAS score, SVA, and EQ5D score. Of 2551 eligible patients, 1738 (mean age 70.2 ± 11.0years; 781 men and 957 women) were enrolled. Trunk muscle mass was significantly correlated with the ODI, VAS score, SVA, and EQ5D score (P < 0.001) when adjusted for age, sex, BMI, ASM, CCI, and history of lumbar surgery. Patient deterioration was associated with a decrease in trunk muscle mass, and the deterioration accelerated from approximately 23kg. Trunk muscle mass was significantly associated with the ODI, VAS score, SVA, and EQ5D score. Trunk muscle mass may assume an important role to elucidate and treat lumbar spinal dysfunction and spinal imbalance. These slides can be retrieved under Electronic Supplementary Material.

Sagittal Imbalance Does Not Influence Cup Anteversion in Total Hip Arthroplasty Dislocations.

Retrospective Cohort. Studies have shown that lumbar fusion procedures are associated with an increased risk of total hip arthroplasty (THA) dislocation. Some have speculated that the increased risk of dislocation is caused by mispositioning of the acetabular component because of spinal sagittal imbalance. Unfortunately, the exact relationship between spinal sagittal balance and cup orientation is unknown. The objective of this study was to investigate the effect of spinal sagittal alignment on cup anteversion in THA dislocation. Patients that suffered a THA dislocation were retrospectively identified. Cross-table lateral hip radiographs were used to measure cup anteversion with normal acetabular anteversion defined as 15±10 degrees. Lateral lumbar spine radiographs were used to measure lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt, and sacral slope. Normal sagittal balance was defined as a PI-LL difference of <10 degrees. The association between sagittal balance and THA characteristics was assessed using Pearson correlation coefficient, χ analysis, and independent t tests. A total of 29 patients had full radiographic imaging. Among these patients, 62.1% dislocated following a primary THA and 37.9% following a revision THA. Abnormal spinal sagittal balance was identified in 20 patients (69.0%). Eight (27.6%) patients had undergone spinal fusion prior to THA. Abnormal cup anteversion was demonstrated in 51.7% of all patients. Presence of a spinal fusion was not associated with cup anteversion, sagittal balance, or time to dislocation. Sagittal balance was not associated with direction of dislocation, time to dislocation, or cup anteversion. A majority of patients with a THA dislocation demonstrated abnormal sagittal balance. However, sagittal balance was not associated with acetabular cup anteversion. As such, the relationship between spinal deformity and dislocation rates after THA may not be because of inaccurate cup orientation.

Short Lumbosacral Decompression Plus Fixation Does Not Change the Spinopelvic Balance on Patients With Moderate Degenerative Spondylolisthesis and Associated Spinal Stenosis

Study DesignA retrospective cohort study. ObjectivesTo investigate whether decompression plus short segment lumbosacral fixation changes the sagittal baseline spinopelvic parameters in patients with moderate degenerative spondylolisthesis (DS) and associated degenerative lumbar spinal stenosis (DLSS). Summary of Background DataSpinal decompression and fusion are commonly performed in DS with associated DLSS. Spinopelvic alignment after surgery for DS is an important research topic. The effect of short lumbosacral instrumented fusion on the global sagittal spinal balance has not been sufficiently studied. MethodsThirty-four consecutive adult patients (21 women, 13 men) aged 62 ± 11 years with balanced spines [sagittal vertical axis (SVA) ≤ 40 mm] received decompression and two to three vertebrae fixation plus fusion for DS grades I and II, associated with symptomatic DLSS. Age, gender, number of segments fused, posterolateral fusion (PLF) versus PLF plus posterior lumbar interbody fusion (PLIF) and segmental lordosis (SL) in the free segment above instrumentation were studied for a minimum follow-up of 60 months. The roentgenographic variables measured are T12–S1 lumbar lordosis (LL), SVA, sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), SL, and anterior (ADH) and posterior disc height (PDH) in the suprajacent free lumbar segment. Clinical outcomes were assessed with visual analog scale and Oswestry Disability Index. ResultsSVA significantly (p = .05) decreased postoperatively but returned to the baseline value at the final observation. Younger individuals (≤59 years) stood with greater SS (p = .036) 6 months postoperatively and with less SVA in all 3 periods of observation (p = .013, .046, and .024) than their older (>59 years) counterparts. Patients with monosegmental stenosis showed on baseline less SVA (p = .028), PT (p = .031), and PI (p = .004) than their two-segmental stenosis counterparts. PI preoperatively to the last evaluation was significantly smaller in the patients who received 360° fusion (p<.016). ConclusionsShort lumbosacral fixation does not significantly change the preoperative sagittal spinopelvic balance in adult patients with preoperatively balanced spines who have DS and DLSS. Level of EvidenceLevel III.

Biomechanical aspects of spinal sagittal balance in achondroplasia patients during Ilizarov limb lengthening

To review specific features of spinal sagittal balance in achondroplasia patients at stages of lower limb lengthening using the Ilizarov method. Material and Methods. Cross-sectional clinical and radiological study was performed in 29 achondroplasia patients prior to lower limb lengthening and at lengthening stages using the Ilizarov method. Parameters of sagittal balance of the spine and pelvis were evaluated radiologically. Clinical evaluation included examination, and assessment of neurological status and pain level. Results. Clinical manifestations of sagittal imbalance included hypokyphosis of the thoracic spine in 44.8 % of cases and increased lumbar lordosis in 55.2 %. No neurological disorders were diagnosed in patients. Pain scores 2 to 4 were observed in 17.2 % ofcases. After staged lower limb lengthening by 19.8 ± 3.3 cm, it was revealed that the values of the thoracic kyphosis, lumbar lordosis and the angle of the sacrum tilt improved and approached those of healthy peers. Vertical sagittal alignment measurements correlated with those of thoracic kyphosis. Thoracic kyphosis showed a correlation with lumbar lordosis. Pelvic indices had a moderate correlation with lumbar lordosis. Conclusion. Biomechanically substantiated transosseous compression-distraction osteosynthesis by Ilizarov technique used for lower limb lengthening in achondroplasia patients improves spinal sagittal balance parameters.

Impact of lumbar arthrodesis on outcomes after elective total hip arthroplasty

BackgroundAcetabular component malpositioning has been associated with major complications including dislocation, edge-loading, stripe wear and squeaking. Anteversion is determined by pelvic orientation; flexion of the pelvis increases and extension decreases acetabular anteversion. The degree of pelvic movement is determined by lumbar spine sagittal balance and it is well established that lumbar arthrodesis procedures influence spinal and pelvic parameters including sagittal balance. The purpose of this study is to determine the impact of prior lumbar arthrodesis and revision lumbar arthrodesis on complications after primary elective THA. MethodsA database review using the entire Medicare sample within the PearlDiver database was performed using International Classification of Diseases, 9th Edition codes. The search identified 14,439 patients who underwent primary THA after prior lumbar arthrodesis and 1,157 patients who underwent primary THA after prior revision lumbar arthrodesis. A search for patients who underwent primary THA without prior history of lumbar or revision lumbar fusion yielded 749,403 patients who served as a control. Incidence (IN), odds ratios (ORs) and their respective 95% confidence intervals (CIs) for 30-day, 90-day and overall complications were calculated. ResultsThe following complications reached statistical significance (p < 0.001) for THA after primary lumbar arthrodesis: bleeding (IN:9.7%, OR:2.33, CI:2.21–2.47), dislocation (IN:5.6%, OR:1.95, CI:1.81–2.09), infection (IN:3.6%, OR:1.99, CI:1.85–2.12), mechanical complication (IN:0.7%, OR:1.42, CI:1.16–1.73), mechanical loosening (IN:2.3%, OR:1.74, CI:1.56–1.94), other mechanical complication (IN:2.1%, OR:2.13, CI:1.90–2.39), DVT/PE (IN:8.4%, OR:1.50, CI:1.42–1.60), acute renal failure (IN:22%, OR:1.20, CI:1.15–1.25), periprosthetic fracture (IN:1.6%, OR:1.45, CI:1.27–1.65), and prosthetic-related complication (IN:30%, OR:1.85, CI:1.78–1.91). Higher complications rates were observed in patients who had revision lumbar arthrodesis: bleeding (IN:12.4%, OR:3.06, CI:2.57–3.65), dislocation (IN:9.7%, OR:3.54, CI:2.92–4.31), infection (IN:5%, OR:3.32, CI:2.71–4.06), mechanical complication (IN:6.9%, OR:14.94, CI:11.88–18.79), mechanical loosening (IN:3.2%, OR:2.41, CI:1.74–3.35), other mechanical complication (IN:3.5%, OR:3.56, CI:2.61–4.87), DVT/PE (IN:10.7%, OR:1.96, CI:1.63–2.36), acute renal failure (IN:25.5%, OR:1.46, CI:1.28–1.66), periprosthetic fracture (IN:2.7%, OR:2.47, CI:1.72–3.52), and prosthetic-related complication (IN:40%, OR:2.88, CI:2.56–3.24). ConclusionsLumbar arthrodesis and revision lumbar arthrodesis significantly negatively impact postoperative complication rates after THA. Level of Evidence: Therapeutic Level III

Characteristic Reconstitution of the Spinal Langerhans Cell Histiocytosis in Young Children.

Pediatric Langerhans cell histiocytosis (LCH) often results in vertebral compression fracture. However, few reports have reported vertebral remodeling during the course of LCH. We aimed to investigate the longitudinal reconstitution and transformation of the affected vertebrae and the adjacent structures in young children with spinal LCH. We recruited 13 patients, including 16 affected vertebrae, diagnosed with LCH via biopsy. The average age at first visit was 3.6 years. The average follow-up period was 10.2 years. Vertebral lesions involved L2 in 3 cases; T12, L1, or L5 in 2 cases; and C4, C5, C7, T5, T8, T9, or L3 in 1 case. We measured the ratios of the height of the affected vertebra and 1 vertebra above the affected one to that of the second vertebra above the affected one, local kyphotic angles, and the ratio of the height of the center of the adjacent disk to that of one disk above it. The collapse of the affected vertebra was most severe after 1 year of disease onset. The rate of reconstitution accelerated at 2 years or later of disease onset. The recovery speed of the anterior wall was faster than that of the center height. While the height of the affected vertebrae was restored, the thickness of the adjacent disk also increased. Further, the height of the adjacent vertebrae increased in a similar manner. The average local kyphosis angle shifted to lordosis within the first 3 years. The heights of not only the disk but also the adjacent vertebra increased during the vertebral collapse phase in pediatric spinal LCH patients. These transformations may affect the realignment of the sagittal spinal balance at the earlier stage of the disease. During the collapse phase, the heights of the adjacent vertebrae and disks increase but after the affected vertebrae reconstituted, the augmentation of adjacent vertebrae and disks diminished. Level IV.

Correlation analysis of sagittal alignment and skeletal muscle mass in patients with spinal degenerative disease

We investigated how skeletal muscle mass (SMM) affects spinal sagittal balance (radiographic parameters) in symptomatic spinal patients. The first purpose of this study was to evaluate the body composition and the spinal sagittal alignment in symptomatic spinal patients. The second purpose of this study was to compare whether the body composition and the spinal sagittal alignment is different in patients with cervical spine disease and lumbar spine disease. We retrospectively evaluated 313 patients who were hospitalized for surgery to treat spinal degenerative disease, who were divided into cervical and lumbar spine disease groups. All patients underwent full-length standing whole-spine radiography and bioimpedance analysis (BIA) before surgery. We used standard measurements to assess the sagittal vertical axis (SVA), cervical lordosis (CL; C2–C7), lumbar lordosis (LL; T12–S1), thoracic kyphosis (TK; T5–12), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). We also analyzed radiological and body composition parameters, patient characteristics, and the correlation between SMM and each sagittal parameters. In the overall cohort, the mean age at the time of operation was 66.5 ± 15.3 years and 59.2% of the patients were men. The correlation coefficients (r) between SMM and PT were negative weak correlation (r = −0.343, P < 0.001). The correlation with SMM for other LL, PI, SS, and SVA was statistically significant, but the correlation was none. In addition, our results also suggested strong correlations (r > 0.5) between LL and SS (r = 0.744), between LL and SVA (r = −0.589), between PT and SS (r = −0.580), and LL and PT (r = −0.506). Fifty-seven patients (18.2%, cervical group) had cervical spine disease and 256 patients (81.8%, lumbar group) had lumbar spine disease. No significant differences in age, height, body weight, and body mass index were observed between the two groups. The SMM of patients with cervical and lumbar spine disease also did not differ significantly. In the lumbar group, correlations were found between SMM and PT (r = −0.288, P < 0.001), between SMM and LL (r = 0.179, P < 0.01), and between SMM and SS (r = 0.170, P < 0.01), while only PT (r = −0.480, P < 0.001) was negatively correlated with SMM in the cervical group. This analysis indicated that PT is the sagittal parameter most closely related to SMM in patients with the spinal degenerative disease. The SMM might be one of the important factors that influenced the posterior inclination of the pelvis in symptomatic spinal patients, especially in cervical spine disease.