Pelvic Angle Research Articles

Motion analysis in patients with postpartum sacroiliac joint dysfunction: A cross-sectional case-control study.

Patients with sacroiliac joint dysfunction are limited in daily life activities such as gait, climbing stairs and rising from a chair. It is well known that individuals with chronic low back pain have impaired balance compared to healthy individuals. This cross-sectional case-control study aims to investigate spatiotemporal parameters, center of pressure and mass, pelvic angles and other joint angles in patients with sacroiliac joint dysfunction in comparison with healthy controls. Motion analysis existed of three tasks: (1) normal gait, (2) single-leg-stance, and (3) sit-to-stance. Spatiotemporal parameters, center of pressure, pelvic angles and other joint angles were measured using a twelve-camera, three-dimensional motion capture system and ground reaction force platforms. Thirty subjects were recruited for this study; ten patients, ten matched controls and ten healthy student controls. For gait, patients had a lower cadence, longer double support phase, shorter step length and slower walking speed than controls. For single-leg-stance, patients had a smaller hip angle of the risen leg than controls. Also, variability in center of pressure was larger in patients. For sit-to-stance, the total time to perform the task was almost doubled for patients compared to controls. This study demonstrates that patients with sacroiliac joint dysfunction have an impaired gait, more balance problems during standing and standing up compared to healthy controls. This novel information assists to further comprehend the pathology and disease burden of sacroiliac joint dysfunction, in addition, it may allow us to evaluate the effect of current therapies.

Roussouly type 2 could evolve into type 1 shape as sagittal spinal alignment deterioration progresses with age.

Cross-sectional study. To identify whether Roussouly type 2 could evolve into type 1 as the deterioration progresses. The study group comprised subjects with a low pelvic incidence (PI). All subjects underwent a standing whole spinal radiograph and sagittal parameters were measured: T1 pelvic angle (TPA), lumbar lordosis (LL), PI, pelvic tilt (PT), L4-S1 angle, thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), lumbar sagittal apex (LSA), lordosis distribution index (LDI) and number of vertebrae included in the lordosis (NVL). All subjects were distributed into two groups; with primary (de novo) degenerative scoliosis (PDS) and without PDS. Subjects without PDS were divided into young adult, adult, middle-aged and elderly groups. The differences in sagittal parameters of each subgroup were compared. In total, 270 subjects were included with a mean age of 58.6 years (range 20-87 years). There was a stepwise increase in the proportion of type 1 with age, whereas type 2 decreased. The TPA, PT, PI-LL, TK, TLK and LDI increased with age in subjects without PDS. The TPA, LDI, TLK and TK increased with age in subjects who displayed type 1, whereas the PT, LL, L4-S1 and PI-LL were unchanged. The TPA, PT, PI-LL and TLK increased with age in subjects who displayed type 2, whereas LL and L4-S1 were decreased, while the LDI and TK remained unchanged. The LSA of subjects without PDS became lower and the NVL decreased with age, with similar phenomena found in the subjects with type 2. There was no statistical difference among the groups for the LSA or NVL distribution of subjects with type 1. The TPA, PT and PI-LL of subjects with PDS were greater than those in Group IV, while the SS, LL and TK were less. The Roussouly-type, NVL and LSA distribution were identical between these two groups. Roussouly type 1 shape may not be an actual individual specific spine type. Rather, type 2 could evolve into the "type 1" shape as deterioration of the sagittal spinal alignment progresses with age. Primary (de novo) degenerative scoliosis had little effect on whether type 2 became type 1. This should be taken into consideration during the assessment and restoration of sagittal balance.

Impact of lumbar fusion on spinopelvic sagittal alignment from standing to sitting position: which factor is associated with postoperative functional limitations due to lumbar stiffness?

To investigate the impact of lumbar fusion on spinopelvic sagittal alignment from standing to sitting position and the influencing factors of postoperative functional limitations due to lumbar stiffness. A total of 107 patients who undertook posterior lumbar interbody fusion were included. Patients were divided into two groups: Group A (lumbosacral fusion; n = 43) and Group B (floating fusion; n = 64). Spinopelvic parameters in standing and sitting position including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), fusion segment lordosis (FSL), upper residual lordosis (URL), lower residual lordosis (LRL), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), sagittal vertical axis (SVA) and T1 pelvic angle (TPA) were measured before and after lumbar fusion. The Lumbar Stiffness Disability Index (LSDI) was used to assess functional limitations due to lumbar stiffness. Accompanied by increased postoperative LSDI, the values of changes from standing to sitting (∆) were reduced in some parameters compared with the preoperative values. ∆PT and ∆SS significantly decreased in both two groups. In Group A, ∆LL significantly decreased with increased ∆URL. In Group B, ∆LL, ∆URL and ∆LRL showed no significant difference before and after surgery. Multiple linear regression analysis showed that age and ∆PT independently influenced the postoperative LSDI in Group A. After lumbar fusion, changes of lumbopelvic sagittal parameters from standing to sitting would be restricted. Adjacent segment lordosis could partially compensate for this restriction. For patients with lumbosacral fusion, postoperative functional limitations due to lumbar stiffness were related to age and the postoperative ∆PT from standing to sitting.

Preliminary Results of Instantaneous Centre of Rotation Change after Thoracic Instrumentation in Adolescent Idiopathic Scoliosis Patients.

The instantaneous centre of rotation (ICR) is the centre of motion with zero velocity where a rigid body moves in a particular plane. ICR, as a dynamic measurement, gives more accurate results in terms of quality and quantity of the vertebral motions compared to range of motion (ROM). We aimed to determine the effect of thoracic instrumentation on cervical movement of adolescent idiopathic scoliosis (AIS) patients who had undergone thoracic level instrumentation by measuring pre-operative and post-operative ICR change in a pilot study. A total of 25 AIS patients were included in this study. C4-C5 and C6-C7 segmental ICR were determined by pre-operative and post-operative cervical flexion-extension radiographs. In addition, cervical sagittal parameters and global sagittal parameters were investigated. There was no statistically significant change in ICR location post-operatively in both x and y coordinates at C4-C5 segment (p: 0.326 and p: 0.946, respectively) and C6-C7 segment (p: 0.209, p: 0.086, respectively). There was a positive correlation between LCL and C4-C5 ICR y coordinate (r: 0.481), but not with C6-C7 ICR y coordinate (r: -0.2, p: 0.398). T5-T12 kyphosis decreased (p: 0.002) and T1 pelvic angle (0.003), SVA (0.02) and sacral slope (0.049) increased significantly post-operatively. T1S was correlated with LCL (r: 0.595, p: 0.002), T5-T12 kyphosis (r: 0.423, p: 0.035), SVA (r: 0.658, p<0.001) and C2-C7 SVA (r: 0.416, p: 0.039). The ICR for cervical region was not changed post-operatively in AIS patients with thoracic instrumentation. There was no relationship found between the development of post-operative cervical kyphosis or lordosis and ICR, which represents the quality and quantity of intervertebral motion. The T1 vertebra plays a key role for cervical, thoracic, and global parameters interaction.

8091 Robot-Assisted Laparoscopic Hysterectomy with Retroperitoneal Uterine Fibroid

<h3>Study Objective</h3> Demonstrate a Robot-Assisted Laparoscopic (RAL) Hysterectomy with a cul-de-sac uterine fibroid, and discuss the benefit of a RAL surgery in these procedures <h3>Design</h3> Narrated video of RAL hysterectomy and exeresis of retroperitoneal mass compatible with fibroid. <h3>Setting</h3> Surgery performed with the patient in lithotomy and Trendelenburg position. Robot was in left lateral pelvic angle. <h3>Patients or Participants</h3> Female, 50 years old, previously diagnosed with fibroid for 8 years. Patient experienced pelvic pain, hypermenorrhea, constipation, and other compressive symptoms. The latter persisted after menopause, with no significant mass reduction. Ultrasound described a 76cc uterus with a solid formation along right lateral uterine wall measuring 12 × 9.4 × 9.3cm. Clinical examination revealed a palpable uterus 3 cm above pubic symphysis, endorsed by imaging findings. <h3>Interventions</h3> Identified a 15cm mobile tumor, suggestive of fibroids in retro uterine region, adhered to the right ovarian fossa with lateralization of the rectum. Ureterolysis was performed and the mass released from the ovarian fossa to the peritoneal reflection of the rectum and uterine torus, aiming the removal of the fibroid en bloc during hysterectomy. <h3>Measurements and Main Results</h3> Operation time was three hours. Patient was early discharged from the hospital, on the first post-operative day with excellent pain control. She evolved without complications during follow-up, being fully discharged with complete symptom improvement. <h3>Conclusion</h3> Minimally invasive surgery has become the standard of therapy for an extensive number of gynecological diseases especially for patients with benign afflictions. Despite most studies proving absence of benefits with RAL when compared to Conventional Laparoscopy, in specific cases, especially when analyzing abnormal form uteri due to myomas, some studies have shown benefit in performing RAL. Increasing accuracy, flexibility and ergonomics can improve results and lead to easier bleeding control as observed in the presented case.

The Standing and Sitting Spino-Pelvic Sagittal Alignment in Patients with Instrumented Lumbar Fusion Might Correlate with Adjacent Segment Degeneration.

Sitting is a common weight-bearing posture, like standing, but there still lacks enough understanding of sagittal alignment in sitting position for patients after lumbar fusion. This study aimed to investigate the accommodation of fixed spine from standing to sitting position and its influence on unfused segments. Sixty-two patients after lumbar fusion (test group) and 40 healthy volunteers (control group) were recruited in this research. All subjects underwent lateral radiographs of entire spine in the standing and sitting positions. The spinopelvic parameters including sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), and pelvic tilt (PT) were measured. The changes in parameters of patients between two positions were compared with control group, and patients were divided in different groups based on fusion level and their parameters were compared. When changing from standing to sitting positions, a forward-moving SVA and TPA were observed in both patients and control groups, accompanied by the decrease in LL, TK and increase in PT, but the changes of patients were smaller in TPA, LL, and TK (6.5° ± 7.2° vs 9.7° ± 6.0°, 7.7° ± 8.3° vs 13.6° ± 8.5°, 2.2° ± 6.5° vs 5.4° ± 5.1°, respectively, p < 0.05). Increase of PT in the lumbosacral fixation group was lower than that in the control group (4.4° ± 9.1° vs 8.3° ± 7.1°, p < 0.05). Patients who had adjacent segments degeneration (ASD) showed more kyphosis in unfused lumbar segments than the other patients (16.4° ± 10.7° vs -1.0° ± 4.8°, p < 0.05) from standing to sitting. The spine straightens in lumbar and thoracic curve, combined with forward-moving axis and pelvic retroversion when changing to the sitting position. However, these changes are relatively limited in patients after lumbar fusion, so the adjacent unfused lumbar segments compensate to stress during sitting and this may be related to ASD.

Relative heights of the withers and the tubera sacrale and angulation of the lumbar and pelvic regions in horses with hindlimb proximal suspensory desmopathy, sacroiliac joint region pain and other orthopaedic injuries

AbstractBackgroundIn non‐lame horses, the tubera sacrale (TS) are usually lower than or, less commonly, equal in height to the withers. Thoracolumbosacral, pelvic and hindlimb posture/conformation may be influenced by musculoskeletal pain, and development and function of epaxial, pelvic and abdominal muscles.ObjectivesTo investigate relationships between (1) conformation of the withers and pelvis and orthopaedic injuries; (2) tarsal angles and relative heights of the withers and TS.Study designRetrospective cross‐sectional clinical study.MethodsHorses (n = 193) presented for lameness or poor performance with a conclusive diagnosis based on abolition of clinical signs by diagnostic anaesthesia and imaging were included. Polystyrene hemispheres were adhered to the withers, TS and tubera ischiadica (TI). Lateral photographs were acquired with each horse standing squarely, with the head and neck in a neutral position, the metatarsal regions vertical, aligned with the TI. Relative heights of the withers and TS were determined using ImageJ. A line from the TS to the TI relative to the horizontal defined the pelvic angle. A line from the TS tangential to the lumbar region relative to the horizontal defined the lumbar angle. Measurements were compared across four injury groups consisting of hindlimb proximal suspensory desmopathy, primary sacroiliac joint region pain, a combination of both, and other causes of lameness.ResultsThe withers height was ≥TS in 138/193 (71.5%) horses; the withers were lower than the TS in 55/193 (28.5%) horses. Pelvic and lumbar angles ranged from 20.0–42.7° (mean 28.9°, SD 3.4°) and 6.3–18.7° (mean 12.2°, SD 2.3°), respectively. No association between measurements and injury groups was determined.Main limitationsThere was a lack of non‐lame control horses. It was not possible to differentiate between innate conformation versus acquired posture.ConclusionsWithers height was &lt;TS in a larger proportion of lame horses compared with published data for non‐lame horses.

Multisegment transforaminal lumbar interbody fusion (TLIF) combined with Ponte osteotomy in degenerative lumbar scoliosis (DLS) surgery: a minimum of five years’ follow-up

PurposeTo evaluate the long-term clinical outcomes of degenerative lumbar scoliosis (DLS) with the administration of multisegment transforaminal lumbar interbody fusion (TLIF) combined with Ponte osteotomy long-level fixation fusion, as well as to identify the factors affecting health-related quality of life (HRQOL).MethodsThis was a retrospective single-centre study involving comprehensive clinical data. The Oswestry Disability Index (ODI), visual analog scale (VAS) outcomes, and Scoliosis Research Society (SRS-22) questionnaire were recorded to assess HRQOL. A correlation analysis was performed to determine the association between HRQOL and radiographic parameters.ResultsA total of 41 consecutive patients (15 males and 26 females) met the inclusion criteria with a follow-up of 8.62 ± 1.20 years. Factors associated with HRQOL were significantly improved post-operation. Global sagittal parameters, including the sagittal vertebral axis (SVA) and T1 pelvic angle (TPA), and local parameters, including apical vertebral translation (AVT) and apical vertebral rotation (AVR), were significantly improved at the last follow-up. Significantly strong correlations between each clinical and radiographic parameter were demonstrated. Moreover, a multiple linear regression analysis demonstrated that the differences in AVT and AVR were significantly correlated with the difference in lumbar lordosis (LL), which was significantly correlated with the differences in SVA and TPA.ConclusionThe surgical treatment of DLS with multisegment TLIF accompanied by Ponte osteotomy and long-level fixations improved the quality of life of patients with a long-term effect. AVR correction is an important factor for LL restoration that significantly correlates with improvements in the sagittal balance parameters SVA and TPA, which are key factors for guaranteeing good HRQOL.

Optimal immediate sagittal alignment for kyphosis in ankylosing spondylitis following corrective osteotomy.

PurposeTo investigate the optimal immediate sagittal alignment of kyphosis in ankylosing spondylitis (AS) following corrective osteotomy.MethodsSeventy-seven AS patients who underwent osteotomy were enrolled. Radiographic parameters, including global kyphosis (GK), lumbar lordosis (LL), T1 spinopelvic inclination (T1SPI), sagittal vertical axis (SVA), T1 pelvic angle (TPA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and PI and LL mismatch (PI–LL), were collected. The clinical outcome was evaluated using the Scoliosis Research Society-22 (SRS-22) questionnaire and Oswestry Disability Index (ODI). At the final follow-up, SVA > 5 cm was regarded as sagittal imbalance, and a total ODI ≤ 20 or total SRS-22 score ≥4 was considered to indicate a good clinical outcome.ResultsSeventy-seven patients with an average age of 37.4 ± 8.6 years were followed up for 29.4 ± 4.2 months. At the final follow-up, GK, LL, PT, SS, TPA, and T1SPI showed some degree of correction loss (P < 0.05). The follow-up parameters could be predicted with the immediate postoperative parameters through their linear regression equation (P < 0.05). The postoperative immediate T1SPI, TPA, SVA, and PI were also highly correlated with the clinical outcome (ODI and/or SRS-22) at the final follow-up (P < 0.05). Based on the relationship, the optimal immediate sagittal alignment for obtaining good clinical outcome was determined: T1SPI ≤ 0.9°, TPA ≤ 31.5°, and SVA ≤ 9.3cm. AS patients with PI ≤ 49.2° were more likely to achieve the optimal alignment and obtained lower ODI and a lower incidence of sagittal imbalance than those with PI > 49.2° at the final follow-up (P < 0.05).ConclusionPostoperative immediate parameters could be used to predict the final follow-up parameters and clinical outcome. The optimal postoperative immediate sagittal alignment of AS patients was T1SPI ≤ 0.9°, TPA ≤ 31.5°, and SVA ≤ 9.3 cm, providing a reference for kyphosis correction and a means for clinical outcome evaluation. Patients with a lower PI (≤49.2°) were more likely to achieve optimal alignment and obtain satisfactory clinical outcomes.

342.1: Comparable Kidney Transplant Outcomes in Selected Patients With a BMI ≥40: A Personalized Medicine Approach To Recipient Selection

Introduction: Kidney transplantation confers a survival benefit compared with dialysis in most studies of obese patients. Yet, many transplant centers decline patients with a body mass index (BMI) ≥40 kg/m2. Our practice relies on computed tomography imaging to evaluate iliac depth and pelvic angle to assess candidacy (see Figure 1). Our aim was to evaluate post-transplant outcomes including survival in patients according to recipient BMI. Methods: We performed a single-center retrospective review of adult kidney transplant alone recipients comparing BMI ≥40 patients (n=84, BMI =42±2 kg/m2) to a matched BMI <40 cohort (n=84, BMI =28±5 kg/m2). Patients were matched for recipient age, gender, race, presence of diabetes, and donor type (living vs. deceased). Results: BMI ≥40 patients were on dialysis longer pre-transplant (5.2±3.2 years vs. 4.1±3.5 years, p=0.03) and received lower kidney donor profile index (KDPI) kidneys (40±25% vs. 53±26%, p=0.003) compared to lower BMI patients. There were no significant differences in prevalence of delayed graft function, reoperations, readmissions, wound complications, patient survival, or renal function at 1 year according to serum creatinine and eGFR. Long-term graft survival was higher for BMI ≥40 patients, including after adjusting for KDPI (BMI ≥40: aHR=1.79, 95% CI=1.09-2.9) (see Figure 2). BMI ≥40 patients had similar weight gain and BMI change in the first year post-transplant (delta weight: BMI ≥40 + 2.5±9.1 kg vs. BMI <40 + 3.0±8.0 kg, p=0.74; delta BMI: BMI ≥40 + 0.9±3.3 vs. BMI <40 + 1.1±3.2, p=0.59). BMI ≥40 patients had a higher mean HbA1c level (6.9±1.7% vs. 5.9±1.4%, p=0.003) at one year post-transplant. Conclusions: Overall patient survival and complications after kidney transplantation were comparable in BMI ≥40 patients compared to a matched cohort with lower BMI with improved long-term graft survival in the obese patients. BMI-based exclusion criteria for kidney transplantation should be reexamined in favor of a more individualized approach.

Crossing the Bridge From Degeneration to Deformity: When Does Sagittal Correction Impact Outcomes in Adult Spinal Deformity Surgery?

Patients with less severe adult spinal deformity (ASD) undergo surgical correction and often achieve good clinical outcomes. However, it is not well understood how much clinical improvement is due to sagittal correction rather than treatment of the spondylotic process. Determine baseline thresholds in radiographic parameters that, when exceeded, may result in substantive clinical improvement from surgical correction. Retrospective. ASD patients with BL and two-year data were included. Parameters assessed: sagittal vertical axis, pelvic incidence-lumbar lordosis mismatch, pelvic tilt, T1 pelvic angle, L1 pelvic angle, L4-S1 lordosis, C2-C7 sagittal vertical axis, C2-T3, C2 slope. Outcomes: Good Outcome (GO) at two years: [meeting either: (1) Substantial Clinical Benefit for Oswestry Disability Index (change >18.8), or (2) Oswestry Disability Index <15 and Scoliosis Research Society Total>4.5]. Binary logistic regression assessed each parameter to determine if correction was more likely needed to achieve GO. Conditional inference tree run machine learning analysis generated baseline thresholds for each parameter, above which, correction was necessary to achieve GO. We included 431 ASD patients. There were 223 (50%) that achieved a GO by two years. Binary logistic regression analysis demonstrated, with increasing baseline severity in deformity, sagittal correction was more often seen in those achieving GO for each parameter(all P <0.001). Of patients with baseline T1 pelvic angle above the threshold, 95% required correction to meet GO (95% vs. 54%, P <0.001). A baseline pelvic incidence-lumbar lordosis >10° (74% of patients meeting GO) needed correction to achieve GO (odds ratio: 2.6, 95% confidence interval: 1.4-4.8). A baseline C2 slope >15° also necessitated correction to obtain clinical success (odds ratio: 7.7, 95% confidence interval: 3.7-15.7). Our study highlighted point may be present at which sagittal correction has an outsized influence on clinical improvement, reflecting the line where deformity becomes a significant contributor to disability. These new thresholds give us insight into which patients may be more suitable for sagittal correction, as opposed to intervention for the spondylotic process only, leading to a more efficient utility of surgical intervention for ASD.

P109. Precontoured rods in achieving planned regional and global alignment: a lot of planning but does it matter in adult spinal deformity? A multicentered study

BACKGROUND CONTEXT The aim of complex spinal deformity correction is to restore both sagittal and coronal balance of the spine. Many studies have shown adverse clinical outcomes related to under and over corrected sagittal and coronal deformities. With proper surgical planning, such under and over correction can be mitigated and patient outcomes can be improved and other complications, such as PJK, can be minimized. PURPOSE Precontoured rod instrumentation for adult spinal deformity (ASD) can accurately achieve planned alignment parameters in the sagittal and coronal planes. STUDY DESIGN/SETTING Multicentered cohort. PATIENT SAMPLE Adult patients (age 18) undergoing instrumentation with pre-contoured rods from 2018-2021. OUTCOME MEASURES Sagittal parameters included C2 slope, cervical lordosis (CL), C2 pelvic angle (CPA), cervicothoracic pelvic angle (CTPA), lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), T1 spinopelvic inclination (T1SPI), T1 slope, T1 slope-CL (T1 slope-CL), thoracic kyphosis (TK), T1 pelvic angle (TPA), C2-C7 SVA (cSVA). Coronal parameters included major coronal curve (MCC) and coronal balance (CVA). METHODS A multicenter cohort of adult patients (age 18) undergoing instrumentation with pre-contoured rods was reviewed from 2018-2021. RESULTS A total of 289 patients were included in the study (mean age: 61.3±13.5yrs, 156 (54%) female, mean total instrumented levels: 8.2±5.0). At 6mo followup, the preoperative plan accurately predicted CL, MCC, and CVA with 71 (62.8%), 33 (68.6%) and 37 (69.8%) patients meeting acceptable criteria (ie, difference of ≤5° or ≤10mm), respectively. However, by 2yrs, accuracy in predicting regional parameters improved including LL (mean error: -3.9±10.2°; P=0.064), PI-LL (-2±9.1°; P=0.265), PT (0.05±5.7°; P=0.968), TK (-6.0±11.3°; 0.059). Similarly, mean errors for global parameters including T1SPI (-1.8±4.2°; 0.126), TPA (-1.8±5.7°, 0.233) and CVA (-1.4±16.8mm, 0.874) were low and statistically insignificant. Although mean differences between plan and 2yr postop for CPA, CTPA, SVA and cSVA were statistically significant, the mean error was 20mm, respectively proving a small clinical difference. CONCLUSIONS In the first and largest, multicenter study with 2-year followup evaluating use of pre-contoured rods, we found high accuracy for both coronal and sagittal correction (regionally and globally) in predicting postoperative alignment parameters. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. The aim of complex spinal deformity correction is to restore both sagittal and coronal balance of the spine. Many studies have shown adverse clinical outcomes related to under and over corrected sagittal and coronal deformities. With proper surgical planning, such under and over correction can be mitigated and patient outcomes can be improved and other complications, such as PJK, can be minimized. Precontoured rod instrumentation for adult spinal deformity (ASD) can accurately achieve planned alignment parameters in the sagittal and coronal planes. Multicentered cohort. Adult patients (age 18) undergoing instrumentation with pre-contoured rods from 2018-2021. Sagittal parameters included C2 slope, cervical lordosis (CL), C2 pelvic angle (CPA), cervicothoracic pelvic angle (CTPA), lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), T1 spinopelvic inclination (T1SPI), T1 slope, T1 slope-CL (T1 slope-CL), thoracic kyphosis (TK), T1 pelvic angle (TPA), C2-C7 SVA (cSVA). Coronal parameters included major coronal curve (MCC) and coronal balance (CVA). A multicenter cohort of adult patients (age 18) undergoing instrumentation with pre-contoured rods was reviewed from 2018-2021. A total of 289 patients were included in the study (mean age: 61.3±13.5yrs, 156 (54%) female, mean total instrumented levels: 8.2±5.0). At 6mo followup, the preoperative plan accurately predicted CL, MCC, and CVA with 71 (62.8%), 33 (68.6%) and 37 (69.8%) patients meeting acceptable criteria (ie, difference of ≤5° or ≤10mm), respectively. However, by 2yrs, accuracy in predicting regional parameters improved including LL (mean error: -3.9±10.2°; P=0.064), PI-LL (-2±9.1°; P=0.265), PT (0.05±5.7°; P=0.968), TK (-6.0±11.3°; 0.059). Similarly, mean errors for global parameters including T1SPI (-1.8±4.2°; 0.126), TPA (-1.8±5.7°, 0.233) and CVA (-1.4±16.8mm, 0.874) were low and statistically insignificant. Although mean differences between plan and 2yr postop for CPA, CTPA, SVA and cSVA were statistically significant, the mean error was 20mm, respectively proving a small clinical difference. In the first and largest, multicenter study with 2-year followup evaluating use of pre-contoured rods, we found high accuracy for both coronal and sagittal correction (regionally and globally) in predicting postoperative alignment parameters.

P48. Mechanisms of lumbar spine ‘flattening’ in adult spinal deformity: defining changes in shape that occur relative to a normative population

<h3>BACKGROUND CONTEXT</h3> Loss of lumbar curvature is often expressed as an angular regional loss. Previous work comparing adult spinal deformity (ASD) lumbar alignment to their age-and-PI adjusted normative value demonstrated that, contrary to general belief, a large proportion of the curvature is lost proximally (L1-L4). This study is a follow-up looking not only at regional angles, but also at the spinal contour collectively. <h3>PURPOSE</h3> Investigate the difference of lumbar shape between ASD and age-and-PI adjusted normative values. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of an ASD registry. <h3>PATIENT SAMPLE</h3> A total of 119 asymptomatic volunteers and 362 ASD patients. <h3>OUTCOME MEASURES</h3> Sagittal alignment of the lumbar and thoracolumbar spine measures using vertebra pelvic angle from L5 to T10. <h3>METHODS</h3> Before studying ASD patients, 119 asymptomatic volunteers with full-body, free-standing radiographs were used to identify age-and-PI models of each vertebra pelvic angle (VPA) from L5 to T10, a validated methodology characterizing the detailed shape of the spine. Our study cohort was a registry of surgical primary ASD patients without coronal malalignment (SRS-Schwab Type=N). The formulas developed in the asymptomatic population were applied to the ASD group to calculate an age-and-PI normative spine shape for each patient. Loss of lumbar lordosis was defined as the offset between age-and-PI normative value and pre-operative spino-pelvic alignment. Patients were stratified into four groups by the amount of lordosis lost, ranging from "no loss" to "30° loss." Paired t-tests were performed to compare actual and normative VPA shapes within each group. <h3>RESULTS</h3> Out of 1,495 patients enrolled in this registry, 453 were primary cases, and 653 were categorized as a Schwab type N, leading to a cohort of 362 patients (age=64.4±13, 57.1% F). Pre-operative alignment demonstrated a large variability with a mean PI-LL of 15°±21, distal LL=31°±15, and PI=55°±13. Compared to their age-and-PI normative values, ASD patients demonstrated a significant lordosis loss of 17°±19 with the following distribution: 14.1% no loss (mean: 0.1±2.3), 22.9% with 10° loss (mean: 9.9±2.9), 22.1% with 20° loss (mean: 20.0±2.8), and 29.3% with 30° loss (mean:33.8±6.0). Comparison of the VPAs (and therefore the shape) between each LL group and the normative shape demonstrated that the "no loss" patients had a lumbar spine slightly anterior to the normative shape from L4 to T10 (VPA difference of 2°). The shape of the "small deformity" group (10°) superimposed on the normative one from L5 to L2 (VPA with p>0.1) and became anterior at the L1 level. As the lordosis loss increased, the offset between ASD and normative shapes began to propagate to the distal levels and became significant extending caudally to the L3 level for the "20° loss" group and further down to L4 for the more severe group. <h3>CONCLUSIONS</h3> As the deformity progresses and the loss of lordosis increases, the difference between ASD shape and normative shape happens first proximally and then progresses incrementally caudally with increasing deformity. Understanding the spinal contour and the location of this loss, in addition to regional parameters, may be key to achieving a sustainable correction by identifying optimal and personalized post-operative shape. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

131. Sagittal profile modifications in vertebral body tethering (VBT) versus posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS)

<h3>BACKGROUND CONTEXT</h3> Sagittal alignment is integral to a patient's quality of life. Posterior spinal fusion (PSF) is currently the standard for correcting adolescent idiopathic scoliosis (AIS). Vertebral body tethering (VBT) is a fusionless growth modulating surgical technique used to treat AIS. It relies on the Hueter-Volkmann Law. Indications for this procedure include patients who have coronal curves up to 50°, growth remaining, and no excessive thoracic kyphosis. VBT has been shown to have good coronal plane deformity correction. There have been fewer examinations of the sagittal effects of VBT. <h3>PURPOSE</h3> To determine if VBT is a non-inferior treatment for correction of AIS with regard to sagittal alignment compared to PSF. <h3>STUDY DESIGN/SETTING</h3> Multicenter retrospective cohort study. <h3>PATIENT SAMPLE</h3> Patients with AIS who underwent correction surgeries with LIV in the lumbar spine from 2013 to 2021 with pre- and minimum two-year postoperative standing full spine plain films. <h3>OUTCOME MEASURES</h3> Sagittal vertical axis (SVA), cervical SVA (cSVA), pelvic tilt (PT), thoracic kyphosis (TK), cervical lordosis (CL), L4-S1 lordosis (L4L), T1 pelvic angle (TPA) and pelvic incidence lumbar lordosis mismatch (PI-LL). <h3>METHODS</h3> Radiographic analyses was completed with independent samples t-test with significance set to p <0.05. <h3>RESULTS</h3> A total of 99 patients were included, 49 VBT and 50 PSF. There were no differences in age or levels instrumented between groups. The VBT cohort Lenke class breakdown is 23% 1A, 13% 1C, 31% 3C. 18% 5C, and 15% 6C, while the PSF cohort consisted of 42% 1A, 6% 1B, 2% 2C, 2% 3B, 12% 3C, 2% 5B, 24% 5C, and 10% 6C. At Baseline, the VBT cohort had lower SVA (-0.7mm±3.7 vs 2.2mm±5.0, p=0.001), CL (-0.9°±18.2 vs 11.6°±12.8, p=0.001), L4-S1 Lordosis (20.7°±16.0 vs 41.6°±10.2, p=0.001), and higher cSVA (3.3mm±1.6 vs -0.95mm±3.1, p=0.001) than those who were fused. Postoperatively, VBT patients have an overall higher L4-S1 Lordosis (36.0°±10.1vs 18.3°±12.5, p=0.001), cSVA (3.4mm±1.4 vs -3.7mm±2.1, p=0.001), and lower CL (-4.3°±18.4 vs 7.0°±12.2, p=0.001). The PSF cohort had a larger change in cSVA (2.8mm±4.0 vs 0mm±1.6, p=0.001) from baseline to 2-year follow-up compared to VBT. No differences in the change of L4-S1 Lordosis (VBT 1.5°±12.3 vs 4.1°±10.9, p=0.3), TPA (VBT -1.6°±6.8 vs -1.4°±8.5, p=0.89), PT (VBT -0.5°±7.8 vs -1.9°±8.5, p=0.42), or PI-LL (0.2°±12.0 vs -0.5°±14.0, p=0.81) were observed. <h3>CONCLUSIONS</h3> VBT and PSF for AIS result in statistically similar changes in sagittal alignment parameters. The fact that we showed similar results comparing sagittal alignment in fusion and VBT groups indicates that VBT is non-inferior from a sagittal perspective. It is important to maintain sagittal alignment when correcting AIS. Future work can examine the long-term effect of VBT on sagittal alignment. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Preoperative prediction of sagittal imbalance in kyphosis secondary to ankylosing spondylitis after one-level three-column osteotomy

BackgroundThis study aimed to determine preoperative predictors for sagittal imbalance in kyphosis secondary to ankylosing spondylitis (AS) after one-level three-column osteotomy.MethodsA total of 55 patients with AS who underwent one-level three-column osteotomy were enrolled. The patients were divided into two groups according to sagittal vertical axis (SVA) value at the final follow-up (group A: SVA > 5 cm; group B: SVA ≤ 5 cm). The radiographic measures included global kyphosis, lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), sacral slope, T1 pelvic angle (TPA), SVA, osteotomized vertebral angle and PI and LL mismatch (PI − LL). Postoperative clinical outcomes were evaluated using Scoliosis Research Society-22 questionnaire (SRS-22) and Oswestry Disability Index (ODI).ResultsFifty-five AS patients had an average follow-up of 30.6 ± 10.2 months (range 24–84 months). Group A had larger preoperative and postoperative LL, PT, PI − LL, TPA and SVA values compared with group B (P < 0.05), and no significant differences were found in ODI and SRS-22 scores between the two groups (P > 0.05). Preoperative LL, PT, PI − LL, TPA, and SVA values were positively correlated with the follow-up SVA value (P < 0.05). Among them, TPA > 40.9°, PI − LL > 32.5° and SVA > 13.7 cm were the top three predictors with the best accuracy to predict sagittal imbalance. Immediate postoperative SVA value of ≤ 7.4 cm was a key factor in reducing the risk of sagittal imbalance during follow-up.ConclusionsPreoperative TPA > 40.9°, PI − LL > 32.5° and SVA > 13.7 cm could predict sagittal imbalance in AS kyphosis after one-level three-column osteotomy, and additional osteotomies were recommended for this condition. Immediate postoperative SVA ≤ 7.4 cm was an optimal indicator for preventing sagittal imbalance.Level of evidenceIV.

Can genetic propensity for lambing difficulty be predicted by pelvic and body shape dimensions measured by X-ray computed tomography (CT) scanning of ram lambs?

The ability of sheep to lamb unaided is important for both financial and welfare reasons. Current recording of lambing ease is subjective and unreliable for breeding purposes. The aim of this study was to investigate genetic control of measurements that could be taken from routine x-ray computed tomography (CT) scanning of ram lambs, within UK breeding programmes, to predict lambing difficulty of their progeny, or their daughters’ progeny. Measurements of 6 CT-derived lambing ease predictor traits (hip width, shoulder width, pelvic area, pelvic height, pelvic width, pelvic angle) were taken from archived CT images from 437 Texel ram lambs from 58 flocks (average age ~20 weeks) scanned over 15 years, as part of the UK national terminal sire breeding programme. Heritabilities, after adjusting for live weight, ranged from 0.16 to 0.65, with the highest estimates for the pelvic traits. Lambing difficulty scores (17705 records over 16 years), recorded on a six-point scale of increasing severity, were available from lambs born within the same flocks. Lambing difficulty was lowly heritable when expressed either as a trait of the lamb (h2 = 0.05) or the ewe (h2 = 0.02) with large common litter effects, low maternal effects and low repeatability in the ewe. Genetic correlations gave some indication that wide hips and shoulders, at a fixed live weight, may be associated with increased lambing difficulty of the lamb (rg = 0.28 and 0.47) and that lower pelvic width and angle (more horizontal) may be associated with increased lambing difficulty of the ewe (rg = −0.22 and −0.39), although standard errors were high. Moderate genetic correlations between body width and pelvic measurements suggest scope to select for optimal combinations of these measurements. Further research in this area could lead to incorporation of robust breeding values for lambing ease into sheep breeding programmes to improve animal welfare.

Role of obesity in less radiographic correction and worse health-related quality-of-life outcomes following minimally invasive deformity surgery.

Minimally invasive surgery (MIS) for adult spinal deformity (ASD) can offer deformity correction with less tissue manipulation and damage. However, the impact of obesity on clinical outcomes and radiographic correction following MIS for ASD is poorly understood. The goal of this study was to determine the role, if any, that obesity has on radiographic correction and health-related quality-of-life measures in MIS for ASD. Data were collected from a multicenter database of MIS for ASD. This was a retrospective review of a prospectively collected database. Patient inclusion criteria were age ≥ 18 years and coronal Cobb angle ≥ 20°, pelvic incidence-lumbar lordosis mismatch ≥ 10°, or sagittal vertical axis (SVA) > 5 cm. A group of patients with body mass index (BMI) < 30 kg/m2 was the control cohort; BMI ≥ 30 kg/m2 was used to define obesity. Obesity cohorts were categorized into BMI 30-34.99 and BMI ≥ 35. All patients had at least 1 year of follow-up. Preoperative and postoperative health-related quality-of-life measures and radiographic parameters, as well as complications, were compared via statistical analysis. A total of 106 patients were available for analysis (69 control, 17 in the BMI 30-34.99 group, and 20 in the BMI ≥ 35 group). The average BMI was 25.24 kg/m2 for the control group versus 32.46 kg/m2 (p < 0.001) and 39.5 kg/m2 (p < 0.001) for the obese groups. Preoperatively, the BMI 30-34.99 group had significantly more prior spine surgery (70.6% vs 42%, p = 0.04) and worse preoperative numeric rating scale leg scores (7.71 vs 5.08, p = 0.001). Postoperatively, the BMI 30-34.99 cohort had worse Oswestry Disability Index scores (33.86 vs 23.55, p = 0.028), greater improvement in numeric rating scale leg scores (-4.88 vs -2.71, p = 0.012), and worse SVA (51.34 vs 26.98, p = 0.042) at 1 year postoperatively. Preoperatively, the BMI ≥ 35 cohort had significantly worse frailty (4.5 vs 3.27, p = 0.001), Oswestry Disability Index scores (52.9 vs 44.83, p = 0.017), and T1 pelvic angle (26.82 vs 20.71, p = 0.038). Postoperatively, after controlling for differences in frailty, the BMI ≥ 35 cohort had significantly less improvement in their Scoliosis Research Society-22 outcomes questionnaire scores (0.603 vs 1.05, p = 0.025), higher SVA (64.71 vs 25.33, p = 0.015) and T1 pelvic angle (22.76 vs 15.48, p = 0.029), and less change in maximum Cobb angle (-3.93 vs -10.71, p = 0.034) at 1 year. The BMI 30-34.99 cohort had significantly more infections (11.8% vs 0%, p = 0.004). The BMI ≥ 35 cohort had significantly more implant complications (30% vs 11.8%, p = 0.014) and revision surgery within 90 days (5% vs 1.4%, p = 0.034). Obese patients who undergo MIS for ASD have less correction of their deformity, worse quality-of-life outcomes, more implant complications and infections, and an increased rate of revision surgery compared with their nonobese counterparts, although both groups benefit from surgery. Appropriate counseling should be provided to obese patients.

Evaluation of dynamic spinal alignment changes and compensation using three-dimensional gait motion analysis for dropped head syndrome

BACKGROUND CONTEXTDynamic kinematic evaluation of spino-pelvic alignment during gait using three-dimensional (3D) motion analysis has been proposed for adult spinal thoracolumbar deformity. That is because conventional full-spine radiographs cannot be used to evaluate dynamic factors. However, dynamic changes in spino-pelvic alignment during gait for dropped head syndrome (DHS) have not been studied using this approach. PURPOSE: This study aimed to assess the dynamic changes in spinal-pelvic alignment during gait in patients with DHS using 3D motion analysis. STUDY DESIGNRetrospective review of collected radiographic and kinematic data. PATIENT SAMPLENineteen DHS patients with neck pain and/or anterior gaze disturbance. OUTCOME MEASURESStatic spino-pelvic radiological alignment, dynamic spino-pelvic kinematic parameters and electromyogram (EMG) data. METHODSCenter of gravity of the head - C7 sagittal vertical axis (CGH-C7 SVA), C2-C7 SVA, T1 slope; cervical lordosis (CL), C7SVA, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT) and pelvic incidence (PI) were assessed using full-spine radiographs in a standing position to assess static spino-pelvic alignment. The 3D gait motion analysis was conducted during gait. Dynamic kinematic parameters were divided into spinal segments: cervical (C-), thoracic (T-), lumbar (L-) and pelvis (P-). Each spinal segment coronal angle to the pelvic angle, each spinal segment sagittal angle to the pelvic angle and pelvic sagittal angle to the horizontal axis were assessed as dynamic spino-pelvic kinematic parameters. Trunk and lower limb muscle activity during gait were assessed using wireless surface EMG analysis. Dynamic spino-pelvic kinematic variables and muscle activity were compared between the first walking lap and the final lap during gait analysis. The change in dynamic kinematic parameters was correlated with static radiological alignment and electromyographic muscular activity change. RESULTSCervical and thoracic anterior tilt increased significantly after an extended period of walking, indicating that dropped head worsened during gait. An increase of cervical anterior tilt during walking was significantly associated with decreased muscle activity in the cervical paraspinal muscles (r=-0.463, P<.05) and latissimus dorsi (r=-0.763, p<.01). Furthermore, significant correlations were found between a change in thoracic sagittal angle to pelvic angle and C7SVA (r=0.683, p<.01) and LL (r=-0.475, p<.05). This means that a larger C7SVA and smaller LL were associated with increased thoracic anterior tilt during gait. CONCLUSIONSThe 3D motion analysis for DHS showed that cervical and thoracic anterior tilt significantly increased after extended walking, resulting in worsening of dropped head. Decreased muscle activity of the neck extensor muscles during gait suggests insufficient neck extensor muscle endurance, which was associated with increased cervical anterior tilt. A greater increase in the thoracic anterior tilt during gait was found in DHS patients with a larger C7SVA and smaller LL due to insufficient thoracolumbar compensation for the dropped head. Correction of the cervical spine alone would not be sufficient to improve dropped head in cases with increased thoracic anterior tilt during gait. The results suggest that C7SVA and LL are crucial parameters in the surgical strategy for DHS.

The T4-L1-Hip Axis

This is a cross-sectional cohort. The aim was to describe sagittal plane alignment and balance in a multinational cohort of nondegenerated, asymptomatic adults. Current sagittal alignment targets were developed using correlations between radiographic and quality-of-life measures in spinal deformity patients, rather than disease-free samples leading to relatively poor accounting for variance within a population. Sagittal balance was defined using vertebral body tilt and spinopelvic alignment was defined as the vertebral pelvic angles from C2 to L5 (vertebral pelvic angle=vertebral tilt+pelvic tilt). Associations with pelvic incidence (PI) were assessed using linear regression. Multivariable linear regression was used to estimate a normal L1-S1 lordosis, adjusting for PI and the L1 pelvic angle (L1PA). Correlation between the L1 and T4 pelvic angles was assessed to define a normal thoracic alignment conditioned on lumbar alignment. Among 320 volunteers from 4 continents, median age was 37% and 60% were female. C2 tilt was independent of PI with minimal variation. PI was inadequate for estimating a normal lumbar lordosis (L1-S1, r2 =0.3), but was strongly associated with the lumbar pelvic angles (L1PA, r2 =0.58). Defining lumbar lordosis as a function of PI and L1PA resulted in high explained variance ( R2 =0.74) and the T4 pelvic angle had near perfect correlation with the L1PA ( r =0.9). We defined normal sagittal balance and spinopelvic alignment in a disease-free international volunteer cohort. Four parameters are either fixed or directly modifiable in surgery and can define a normal thoracic and lumbar alignment: the L1-S1 lordosis defined as a function of PI and the L1PA; and the T4 pelvic angle is nearly equivalent to the L1PA, aligning the T4-L1-hip axis.

Validity and Reliability of the Leomo Motion-Tracking Device Based on Inertial Measurement Unit with an Optoelectronic Camera System for Cycling Pedaling Evaluation.

Background: The use of inertial measurement sensors (IMUs), in the search for a more ecological measure, is spreading among sports professionals with the aim of improving the sports performance of cyclists. The kinematic evaluation using the Leomo system (TYPE-R, Leomo, Boulder, CO, USA) has become popular. Purpose: The present study aimed to evaluate the reliability and validity of the Leomo system by measuring the angular kinematics of the lower extremities in the sagittal plane during pedaling at different intensities compared to a gold-standard motion capture camera system (OptiTrack, Natural Point, Inc., Corvallis, OR, USA). Methods: Twenty-four elite cyclists recruited from national and international cycling teams performed two 6-min cycles of cycling on a cycle ergometer at two different intensities (first ventilatory threshold (VT1) and second ventilatory threshold (VT2)) in random order, with a 5 min rest between intensity conditions. The reliability and validity of the Leomo system versus the motion capture system were evaluated. Results: Both systems showed high validity and were consistently excellent in foot angular range Q1 (FAR (Q1)) and foot angular range (FAR) (ICC-VT1 between 0.91 and 0.95 and ICC-VT2 between 0.88 and 0.97), while the variables leg angular range (LAR) and pelvic angle showed a modest validity (ICC-VT1 from 0.52 to 0.71 and ICC-VT2 between 0.61 and 0.67). Compared with Optitrack, Leomo overestimated all the variables, especially the LAR and pelvic angle values, in a range between 12 and 15°. Conclusions: Leomo is a reliable and valid tool for analyzing the ranges of motion of the cyclist’s lower limbs in the sagittal plane, especially for the variables FAR (Q1) and FAR. However, its systematic error for FAR and Pelvic Angle values must be considered in sports performance analysis.