Global Range Of Motion Research Articles

Defining the glenohumeral range of motion required for overhead shoulder mobility: an observational study.

Recovery of overhead mobility after shoulder surgery is time-consuming and important for patient satisfaction. Overhead stretching and mobilization of the scapulothoracic and glenohumeral (GH) joints are common treatment interventions. The isolated GH range of motion (ROM) of flexion, abduction, and external rotation required to move above 120° of global shoulder flexion in the clinical setting remains unclear. This study clarified the GH ROM needed for overhead mobility. The timely development of shoulder ROM in patients after shoulder surgery was analyzed. Passive global shoulder flexion, GH flexion, abduction, and external rotation ROM were measured using goniometry and visually at 2-week intervals starting 6-week postsurgery until the end of treatment. Receiver operating characteristic curves were used to identify the GH ROM cutoff values allowing overhead mobility. A total of 21 patients (mean age 49 years; 76% men) after rotator cuff repair (71%), Latarjet shoulder stabilization (19%), and arthroscopic biceps tenotomy (10%) were included. The ROM cutoff value that accurately allowed overhead mobility was 83° for GH flexion and abduction with the area under the curve (AUC) ranging from 0.90 to 0.93 (p < 0.001). The cutoff value for GH external rotation was 53% of the amount of movement on the opposite side (AUC 0.87, p < 0.001). Global shoulder flexion above 120° needs almost full GH flexion and abduction to be executable. External rotation ROM seems less important as long as it reaches over 53% of the opposite side.

Evaluating the biomechanical effects of pedicle subtraction osteotomy at different lumbar levels: a finite element investigation

BACKGROUNDPedicle subtraction osteotomy (PSO) is effective for correcting spinal malalignment but is associated with high complication rates. The biomechanical effect of different PSO levels remains unclear, and no finite element (FE) analysis has compared L2-, L3-, L4-, and L5-PSOs. PURPOSETo assess the effects of PSO level on the spine's global range of motion, stresses on posterior instrumentation, load sharing with the anterior column, and proximal junctional stresses. STUDY DESIGNA computational biomechanical analysis. METHODSA validated 3D spinopelvic FE model (T10-Pelvis) was used to perform PSOs at L2, L3, L4 and L5. Each model was instrumented with a 4-rod configuration (primary rods + in-line satellite rods) from T11-Pelvis. Simulation included a 2-step analysis; (1) applying 300 N to thoracic, 400 N to lumbar, and 400 N to sacrum, and (2) applying a 7.5 Nm moment to the top endplate of the T10 vertebral body. Acetabulum surfaces were fixed in all degrees of freedom. The range of motion, spinopelvic parameters (lumbar lordosis [LL], sacral slope [SS], pelvic incidence [PI], and pelvic tilt [PT]), PSO force, and von Mises stresses were measured. All models were compared with the L3-PSO model and percentage differences were captured. RESULTSCompared to the intact alignment: LL increased by 48%, 45%, 59%, and 56% in the L2-, L3-, L4-, and L5-PSO models; SS increased by 25%, 15%, and 11% while PT decreased by 76%, 53%, and 45% in L2-, L3-, and L4-PSOs (SS and PT approximated intact model in L5-PSO); Lumbar osteotomy did not affect the PI. Compared to L3-PSO: L2-, L4-, and L5-PSOs showed up to 32%, 34%, and 34% lower global ROM. The least T10-T11 ROM was observed in L5-PSO. The left and right SIJ ROM were approximately similar in each model. Amongst all, the L5-PSO model showed the least ROM at the SIJ. Compared to L3-PSO, the L2-, L4-, and L5-PSO models showed up to 67%, 61%, and 78% reduced stresses at the UIV, respectively. Minimum stress at UIV+ was observed in the L3-PSO model. The L2-and L3-PSOs showed the maximum PSO force. The L5-PSO model showed the lowest stresses on the primary rods in all motions. CONCLUSIONOur FE investigation indicates that L5-PSO results in the greatest lumbar lordosis and lowest global, SIJ, and T10-T11 ROMs and stresses on the primary rods, suggesting potential mechanical benefits in reducing the risk of rod breakage. However, L4- and L5-PSOs led to the least force across the osteotomy site, which may increase the risk of pseudarthrosis. These findings provide biomechanical insights that may inform surgical planning, though further clinical investigation is essential to determine the optimal PSO level and validate these results. CLINICAL SIGNIFICANCEUnderstanding the biomechanical impact of PSO level is crucial for optimizing surgical outcomes and minimizing the risks of postoperative complications.

Anterior cervical hybrid constructs reduce superior adjacent segment burden compared to multilevel anterior cervical discectomy and fusion.

Traditional surgical treatment for symptomatic cervical degenerative disc disease is anterior cervical discectomy and fusion (ACDF), yet the increased risk of adjacent segment degeneration (ASD) requiring additional surgery exists and may result in limiting long-term surgical success when it occurs. Disc arthroplasty can preserve or restore physiologic range of motion (ROM), decreasing adjacent level stress and subsequent surgery. For patients with multilevel pathology requiring at least a 1-level fusion, interest is growing in anterior cervical hybrid (ACH) surgery as a partial motion-preserving procedure to decrease the adjacent level burden. This radiographic study compares postoperative superior adjacent segment motion between ACH and ACDF. Secondarily, total global motion, construct motion, inferior adjacent segment motion, and sagittal alignment parameters were compared. This is a single-center, multi-surgeon, retrospective cohort study of 2- and 3-level ACH and ACDF cases between 2013 and 2021. Degrees of motion were analyzed on flexion/extension views using Cobb angles to measure global (C2-C7) construct and adjacent segment lordosis. Neutral lateral X-rays were analyzed for alignment parameters, including global lordosis, cervical sagittal vertical axis (cSVA), and T1 slope (T1S). Differences were determined by independent t-test and Fisher's exact test. Of 100 patients, 38% were 2-level cases (47% ACH, 53% ACDF) and 62% were 3-level cases: (52% ACH, 48% ACDF). Postoperatively, superior adjacent segment motion increased with ACDF and decreased with ACH (-1.3°±5.3° ACH, 1.6°±4.6° ACDF, P=0.005). Postoperatively, the ACH group had greater ROM across the construct (16.3°±8.7° ACH, 4.7°±3.3° ACDF, P<0.001) and total global ROM (38.0°±12.8° ACH, 28.0°±11.1° ACDF, P<0.001). ACH resulted in a significant reduction of motion loss across the construct (-10.0°±11.7° ACH, -18.1°±10.8° ACDF, P<0.001). Postoperative alignment restoration was similar between both cohorts (-2.61°±8.36° ACH, 0.04°±12.24° ACDF, P=0.21). Compared to ACDF, hybrid constructs partially preserved motion across operative levels and had greater postoperative global ROM without increasing superior adjacent segment mobility or sacrificing alignment restoration. This supports the consideration of ACH in patients with multilevel degenerative cervical pathology requiring at least a 1-level fusion and suggests a propensity for long-term success by reducing the superior adjacent segment burden.

Biomechanical Effect of Different Posterior Fixation Techniques on Stability and Adjacent Segment Degeneration in Treating Thoracolumbar Burst Fracture With Osteoporosis: A Finite Element Analysis.

Finite element analysis. To investigate the biomechanical effect of four posterior fixation techniques on stability and adjacent segment degeneration in treating thoracolumbar burst fractures with osteoporosis. In terms of stability and adjacent segment degeneration, there remains no consensus or guidelines on the optimal technique for the treatment of thoracolumbar burst fractures in patients with osteoporosis. Images of CT scans were imported into MIMICS and further processed by Geomagic to build three-dimensional models of the T10-L5 region. A v-shaped osteotomy was performed on the L1 vertebral body to simulate a burst fracture in the setting of osteoporosis. Subsequently, four fixation techniques were designed using SolidWorks software. Range of motion (ROM) of the global spine, ROM distribution, ROM of adjacent segment, Von Mises stress on adjacent intervertebral disks, and facet joints were analyzed. Among the four groups, the cortical bone screw fixation (CBT) showed the highest global ROM at 1.86°, while long-segmented pedicle screw fixation (LSPS) had the lowest global ROM at 1.25°. The LSPS had the smallest percentage of ROM of fractured vertebral body to fixed segment at 75.04%, suggesting the highest stability after fixation. The maximum ROM of the adjacent segment was observed in the CBT at 1.32°, while the LSPS exhibited the smallest at 0.89°. However, the LSPS group experienced larger maximum stress on the adjacent intervertebral disks (9.60MPa) and facet joints (3.36MPa), indicating an increasing risk of adjacent segment disease. LSPS provided the greatest stability, while CBT provided the smallest amount of stability. However, the elevated stress on adjacent intervertebral disks and facet joints after LSPS fixation increased the possibility of adjacent segment degeneration. Cement-augmented pedicle screw fixation (CAPS) and combined cortical bone screw and pedicle screw fixation (CBT-PS) demonstrated significant biomechanical advantages in providing moderate fixation strength while reducing stress on the intervertebral disks and facet joints.

Understanding overall shoulder function and health: the value of specific quantitative vs. qualitative shoulder range of motion on patient-reported outcome measures

Hypothesis and BackgroundIt is known that, though widely used, shoulder range of motion (ROM) measurements are not standardized and have a high rate of intra- and interobserver differences. Particularly, the inconsistency in quantitative and qualitative measurements and their relationship to patient-reported outcome measures (PROMs) make shoulder health difficult to determine. MethodsThis was a prospective study of 147 patients who presented with a chief complaint of shoulder pain to the orthopedic sports medicine and shoulder clinic of a single fellowship-trained surgeon. Measured by one examiner, quantitative ROM measurements were taken with a goniometer and qualitative ROM measured by the anatomic level that the patient could reach. The following PROMs were used as well: American Shoulder and Elbow Surgeons Shoulder Score (ASES), Single Assessment Numeric Evaluation (SANE), Shoulder Pain and Disability Index (SPADI), Oxford Shoulder Score (OSS), Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH), 12-Item Short Form Health Survey (SF-12), and Patient-Reported Outcomes Measurement Information System pain interference short form 6a (PROMIS 6a). Statistical analysis was performed with SPSS using Pearson correlation and two-sample t-test. Benjamini-Hochberg correction was used to determine p-value at which statistical significance was reached to correct for multiple comparisons. ResultsQualitative internal rotation (IR), (the hand behind back reach test) and qualitative forward flexion (FF) correlated with all goniometer angle measurements and PROMs (both shoulder and general health scores). These qualitative measures proved to be an appropriate proxy for IR and FF goniometer measurements. Qualitative external rotation (ER) was not a good substitute for quantitative ER measurement. Quantitative ER correlated with all PROMs. As ROM increased when measured by quantitative ER, qualitative IR, and qualitative FF, shoulder and general health PROMs incrementally increased as well. Discussion/ConclusionQualitative IR measurement, the hand-behind-back reach test, is an adequate substitution for IR goniometer angle as well as a strong representation of global shoulder ROM, shoulder health, and general health while factoring in patient age. Qualitative FF measurement is also an appropriate proxy for quantitative FF and represents global shoulder and general health without factoring in age. Quantitative ER via goniometer angle, is a better assessment of the shoulder than qualitative ER and is a representation of overall shoulder and general health. We recommend the use of quantitative ER, qualitative IR, and qualitative FF measurements to best understand a patient’s overall shoulder health and its impact on their overall health.

Arthroscopic Lysis of Adhesions for Stiffness After Surgical Management of Proximal Humerus Fractures Leads to Satisfactory Outcomes in Most Patients

To report patient-reported outcomes (PROs), range of motion (ROM), and satisfaction, in patients who underwent arthroscopic lysis of adhesions for stiffness after open reduction with internal fixation (ORIF) or reverse shoulder arthroplasty (RSA) for fracture. A retrospective review was performed to identify patients with stiffness who underwent arthroscopic lysis of adhesions following ORIF or RSA for proximal humerus fracture at a single institution between 2012 and 2021 with minimum 1-year follow-up. PROs including visual analog scale for pain (VAS), American Shoulder and Elbow Surgeons (ASES), and Subjective Shoulder Value (SSV), as well as active ROM including forward flexion (FF), external rotation (ER), internal rotation (IR), were collected pre- and postoperatively. Attempted nonoperative treatment before arthroscopic lysis of adhesions was documented. Complications and satisfaction were also recorded. A total of 21 patients met the study criteria (4 RSA, 17 ORIF), with an average age of 66.7 ± 8 years. The study sample comprised mostly of female patients (90%). The mean time from the index surgery to arthroscopy was 9 months, and mean follow-up post-lysis was 17 months. Patients with ORIF reported significant pain relief (VAS, Δ -3.2) and improvement in range of motion (FF, Δ 36°; ER, Δ 20°; IR Δ 3 spinal levels) and PROs (ASES, Δ 34.7; SSV Δ 44.8) (P < .01) after lysis. Patients with RSA had significant improvement in ASES (Δ 21.8; P= .04), SSV (Δ 8.8; P= .04), and FF (Δ38; P= .02) but did not have significant improvement in VAS (Δ -2; P= .2), ER (Δ 0°; P= 1.0), and IR (Δ 1 spinal level; P= .2). Satisfaction was 100% in the RSA cohort and 82% in the ORIF cohort. No complications were observed. Arthroscopic lysis of adhesions for stiffness after surgical management of proximal humerus fracture leads to satisfactory outcomes in most patients. Post-ORIF, patients may achieve improvement in PROs and global ROM, whereas post-RSA, patients may achieve improvement in PROs and FF but do not necessarily improve in rotational ROM. Level IV, therapeutic case series.

Comparative Analysis of Eccentric Glenosphere in Reverse Total Shoulder Arthroplasty: A Computer Simulation Study.

The aim was to evaluate the effects of different glenosphere eccentricities on impingement, range of motion (ROM), and muscle length during standard activities in reverse total shoulder arthroplasty (RSA). In this study, we utilized computational modeling techniques to create native shoulder and shoulder models undergoing RSA and simulate shoulder movements in all abduction-adduction, flexion-extension, and rotation. We tested a total of 36 different glenosphere configurations, which included three different inferior tilts (0°, +10°, +20°) and two different lateral offsets (0 mm and +4 mm), as well as six different glenosphere eccentricities (concentricity, inferior, posterior, anterior, anteroinferior, and posteroinferior). We evaluated the maximum impingement-free ROM, impingement sites, and muscle lengths. All glenosphere configurations exceeded 50% of native shoulder ROM in three planes and total global ROM. In abduction-adduction, there was no significant difference among the different glenosphere eccentricities (p > 0.05). In flexion-extension, the posteroinferior eccentricity had the maximum ROM among the different eccentricities, but no significant difference among the different glenosphere eccentricities (p > 0.05). In rotation, there was a significant difference overall, and anteroinferior eccentricity had a significant advantage over concentricity (p < 0.05). In total global ROM, anteroinferior eccentricity had a significant advantage over concentricity when lateral offset was 0 mm (p < 0.05). In all models of glenosphere eccentricities, only the elongation of the infraspinatus muscle was statistically significant (p < 0.05). Glenosphere eccentricity significantly influenced rotation, total global ROM, and the length of the subscapularis muscle. Among them, anteroinferior offset achieved the maximum ROM in abduction-adduction, rotation, and total global activities. Both anteroinferior and inferior glenoid eccentricity showed significant advantages over the concentricity in rotation and total global ROM. Basic Science Study; Computer Modeling.

Radiological Outcomes of Unilateral Laminotomy for Bilateral Decompression in Lumbar Spinal Stenosis With and Without Discectomy

Unilateral laminotomy for bilateral decompression (ULBD) is a minimally invasive surgical technique widely used in patients with lumbar spinal stenosis and low-grade spondylolisthesis. However, few studies have investigated the long-term effects of the unilateral approach of ULBD on postoperative coronal imbalance, and the effect of additional discectomy on ULBD has not yet been evaluated in detail. Sixty-one patients with lumbar spinal stenosis who underwent ULBD with or without discectomy were identified. The ULBD with discectomy group included 27 patients, and the ULBD without discectomy group included 34 patients. We analyzed the changes in various radiographic parameters, such as global lordosis (GL), segmental lordosis (SL), global coronal angle (GCA), segmental coronal angle (SCA), disc height (DH), global range of motion (GROM), and segmental range of motion (SROM) following the surgery and compared these parameters between the two groups. In patients who underwent ULBD with discectomy, segmental coronal angle (SCA) significantly decreased from 0.42±4.41 (°±SD) preoperatively to-0.31±4.87 postoperatively (P=0.026), while disc height (DH) decreased from 8.80±2.49 (mm±SD) to 7.32±2.60 (P<0.001). These findings suggest a reduction in convexity as disc height decreased on the laminotomy side. However, the absolute SCA value tended to approach 0° postoperatively regardless of discectomy, indicating that the preoperative scoliosis has improved. In both groups, the lordotic angles and range of motion (ROM) parameters showed no changes before and after surgery. ULBD preserved lumbar lordosis and motion with or without discectomy during the 2-year follow-up period. Improvement in coronal balance was observed after ULBD regardless of discectomy, without significant negative effects on sagittal and coronal spine stability.

Quantitatively biomechanical response analysis of posterior musculature reconstruction in cervical single-door laminoplasty

Background and objectiveThe current trend of laminoplasty is developing toward the goal of muscle preservation and minimum tissue damage. Given this, muscle-preserving techniques in cervical single-door laminoplasty have been modified with protecting the spinous processes at the sites of C2 and/or C7 muscle attachment and reconstruct the posterior musculature in recent years. To date, no study has reported the effect of preserving the posterior musculature during the reconstruction. The purpose of this study is to quantitatively evaluate the biomechanical effect of multiple modified single-door laminoplasty procedures for restoring stability and reducing response level on the cervical spine. MethodsDifferent cervical laminoplasty models were established for evaluating kinematics and response simulations based on a detailed finite element (FE) head-neck active model (HNAM), including ① C3 – C7 laminoplasty (LP_C37), ② C3 – C6 laminoplasty with C7 spinous process preservation (LP_C36), ③ C3 laminectomy hybrid decompression with C4 – C6 laminoplasty (LT_C3 + LP_C46) and ④ C3 – C7 laminoplasty with unilateral musculature preservation (LP_C37 + UMP). The laminoplasty model was validated by the global range of motion (ROM) and percentage changes relative to the intact state. The C2 – T1 ROM, axial muscle tensile force, and stress/strain levels of functional spinal units were compared among the different laminoplasty groups. The obtained effects were further analysed by comparison with a review of clinical data on cervical laminoplasty scenarios. ResultsAnalysis of the locations of concentration of muscle load showed that the C2 muscle attachment sustained more tensile loading than the C7 muscle attachment, primarily in flexion-extension (FE) and in lateral bending (LB) and axial rotation (AR), respectively. Simulated results further quantified that LP_C36 primarily produced 10% decreases in LB and AR modes relative to LP_C37. Compared with LP_C36, LT_C3 + LP_C46 resulted in approximately 30% decreases in FE motion; LP C37 + UMP also showed a similar trend. Additionally, when compared to LP_C37, LT_C3 + LP_C46 and LP C37 + UMP reduced the peak stress level at the intervertebral disc by at most 2-fold as well as the peak strain level of the facet joint capsule by 2–3-fold. All these findings were well correlated with the result of clinical studies comparing modified laminoplasty and classic laminoplasty. ConclusionsModified muscle-preserving laminoplasty is superior to classic laminoplasty due to the biomechanical effect of the posterior musculature reconstruction, with a retained postoperative ROM and loading response levels of the functional spinal units. More motion-sparing is beneficial for increasing cervical stability, which probably accelerates the recovery of postoperative neck movement and reduces the risk of the complication for eventual kyphosis and axial pain. Surgeons are encouraged to make every effort to preserve the attachment of the C2 whenever feasible in laminoplasty.

Anterior Bone Loss after Cervical Baguera C Disc versus Bryan Disc Arthroplasty.

The objectives of this study were to identify the risk factors and incidence of anterior bone loss (ABL) after Baguera C cervical disc arthroplasty (CDA) and identify whether design differences in artificial discs affect ABL. In this retrospective radiological review of patients who underwent single-level Baguera C CDA in a medical center, the extent of ABL and the following radiological parameters were recorded: global and segmental alignment angle, lordotic angle (or functional spinal unit angle), shell angle, global range of motion (ROM), and ROM of the index level. ABL at the index level was grade 0-2. Grade 0 was defined as no remodeling, grade 1 as spur disappearance or mild change in body contour, and grade 2 as obvious bone regression with Baguera C Disc exposure. Combining grade 1 and grade 2, ABL was found in 56 upper adjacent vertebrae and 52 lower adjacent vertebrae of the 77 patients. Only 18 patients (23.4%) had no ABL. Shell angle differed significantly between ABL grades of both the upper and lower adjacent level: 0.0° in grade 0 and 1 ABL vs. 2.0° in grade 2 ABL of the upper adjacent level (p < 0.05); and 0.0° in grade 0 and 1 ABL vs. 3.5° in grade 2 ABL of the lower adjacent level (p < 0.05). A female predominance of ABL was found. Hybrid surgery and artificial disc size were also related to ABL. ABL is more common in Baguera C Disc arthroplasty than Bryan Disc arthroplasty. Larger shell angle was related to ABL after CDA with Baguera C Discs, which may indicate that shell angle is pivotal in determining the incidence of ABL after CDA. Females had more ABL with Baguera C Disc arthroplasty; this might be related to shorter endplate lengths as well as a smaller endplate-implant mismatch.

Association between age, sex and cervical and upper cervical rotation tests. Descriptive and correlational study in healthy volunteers.

Active cervical spine rotation (ACROM Rot) shows cervical rotation and flexion rotation test (FRT); side-bending rotation test (SBRT) and upper cervical axial rotation test (C0-C2ART) are described to measure upper cervical rotation. The objectives of this study are (1) to describe the normal range of motion (ROM) of ACROM Rot, and the ROM in FRT, SBRT and C0-C2ART tests; (2) to explore the correlation among the four tests and (3) to investigate the influence of age and sex in their ROM. A cross-sectional study was carried out with healthy volunteers from 18 to 75 years of age. Tests were measured using a CROM device and a bubble inclinometer. Descriptive analysis was performed to establish normative data for the ROM tests. Correlation analysis was conducted to understand the relation between upper and global cervical rotation ROM and among the three upper cervical rotation tests. Linear regression models were developed to understand the influence of age and sex in the ROM of all tests. Normative values were obtained from 122 healthy volunteers (50% male), by sex and age strata. The degree of correlation ranged between 0.582 (p < 0.01) for FRT and ACROM Rot left and 0.217 (p < 0.05) for SBRT and C0-C2ART left. Linear regression models showed the influence of sex for ACROM Rot right (men -4.64° less than women), SBRT (men -4.1° less than women) left and C0-C2ART right and left (men -2.24° and -1.78° less than women). The age influenced rotation ROM with a decrease for every 10 years of -2.11° and -1.96° for ACROM Rot right and left, of -1.72° and -1.26° for FRT right and left and -0.58° and -0.41° for C0-C2ART right and left in the linear regression models. No association was found between age and SBRT (p = 0.63 for right SBRT and p = 0.49 for left SBRT). Weak-to-moderate correlation was found between the upper cervical spine rotation tests and with the ACROM. Women had a larger ROM in ACROM Rot right, SBRT left and C0-C2ART. Decreases in ROM related with age were observed for ACROM Rot, FRT and C0-C2ART but not for SBRT.

Posteroinferior relevant scapular neck offset in reverse shoulder arthroplasty: key player for motion and friction-type impingement in a computer model.

Range of motion (ROM) and prevention of notching remain a challenge for reverse shoulder arthroplasty (RSA). Both may be affected by the morphology of the scapula. The purpose of this study was to define anteroinferior (a) and posteroinferior (p) relevant scapular neck offset (RSNO) and to examine the hypothesis that pRSNO is significantly smaller than aRSNO, and influences rigid body motion (RBM). Adapting glenosphere implantation strategies may therefore be of value. In this computer model study, we used deidentified computed tomographic scans of 22 patients (11 male and 11 female; mean age: 72.9 years) with massive cuff tears without joint space narrowing. Eight RSA glenoid configurations were tested with a constant neck-shaft angle (145°). Two baseplate types (25 mm; 25 + 3 mm lateralized) and 4 glenospheres (GS) (36 mm; 36 +2 mm of eccentricity; 39 mm; 39 + 3 mm) were used. RSNO was defined as the standardized measurement of the horizontal distance from the inferior extent of the GS to the bony margin of the scapula after baseplate positioning (flush to inferior glenoid extent; neutral position: 0° inclination and 0° version-both software computed). There was a highly significant difference between pRSNO and aRSNO for both genders (P<.001). pRSNO was always smaller than aRSNO. pRSNO was strongly correlated with external rotation (ERO: 0.84) and extension (EXT: 0.74) and moderately correlated with global ROM (GROM: 0.68). There was a moderately strong correlation between aRSNO and internal rotation (IRO: 0.69). pRSNO was strongly correlated with aRSNO, EXT, ERO, IRO, adduction (ADD) and GROM (0.82, 0.72, 0,8, 0.71, 0.82, 0.76) in female patients and with EXT and ERO (0.82, 0.89) in male patients. The median pRSNO allowing for at least 45° ERO and 40° EXT was 14.2 mm for men and 13.8 mm for women. For all patients and models, pRSNO ≥14 mm increased EXT, ERO, and GROM significantly compared with pRSNO <14 mm (P<.001). The combination of lateralization and inferior overhang (eccentricity) led to the most significant increase of pRSNO for each GS size (P<.001). This is one of the first RSA modeling studies evaluating nonarthritic glenoids of both genders. The lateral scapular extent to glenoid relationship is asymmetric. pRSNO is always smaller than aRSNO for both genders and was a critical variable for EXT and ERO, demonstrating additional strong correlation with aRSNO, IRO, ADD, and GROM in female patients. pRSNO ≥14 mm was a safe value to prevent friction-type impingement. Combining increased glenosphere size, lateralization, and inferior overhang gives the best results in this computer-simulated setting.

The effect of vertebral body tethering on spine range of motion in adolescent idiopathic scoliosis: a pilot study.

Posterior spinal fusion and instrumentation (PSF) and vertebral body tethering (VBT) are corrective surgical techniques used in treating adolescent idiopathic scoliosis (AIS). Comparing the preservation of spine range of motion (ROM) following PSF and VBT for treatment of AIS has yet to be explored. The purpose of this work was to retrospectively compare global spine ROM in adolescents (9-18years of age) without spine deformity, adolescents with untreated AIS, adolescents having undergone PSF, and adolescents having undergone VBT to gain insight on the effect of VBT on spine motion. Twenty participants were recruited into four groups including Control (n = 6), untreated AIS (n = 5), post-operative PSF (n = 4) and post-operative VBT (n = 5). Three-dimensional kinematics of the spine were collected and analyzed using an intersegmental spine model during constrained forward flexion, right-left lateral bending, and right-left axial twist movements. The PSF group displayed significantly lower spine ROM than the two non-operative groups during thoracic and total left axial twist (p ≤ 0.048), whereas thoracic and total ROM during right-left lateral bending is almost equally lower in the PSF (p ≤ 0.03) and VBT (p ≤ 0.01) groups when compared to the Control and AIS groups. These results suggest some preservation of spine motion in the transverse plane following VBT. This study provides initial evidence of some potential preservation of spine ROM following VBT; however, further prospective investigation of VBT is needed to assess and confirm these hypotheses.

P24. Is there a benefit to increasing number of rods (4-, 5-, and 6-) across a lumbar PSO? A finite element analysis

P24. Is there a benefit to increasing number of rods (4-, 5-, and 6-) across a lumbar PSO? A finite element analysis

183. The ideal satellite rod configuration spanning a lumbar pedicle subtraction osteotomy: a finite element analysis

183. The ideal satellite rod configuration spanning a lumbar pedicle subtraction osteotomy: a finite element analysis

Biomechanical analysis of laminectomy, laminoplasty, posterior decompression with instrumented fusion, and anterior decompression with fusion for the kyphotic cervical spine.

Anterior and posterior decompressions for cervical myelopathy and radiculopathy may lead to clinical improvements. However, patients with kyphotic cervical alignment have sometimes shown poor clinical outcomes with posterior decompression. There is a lack on report of mechanical analysis of the decompression procedures for kyphotic cervical alignment. This study employed a three-dimensional finite element (FE) model of the cervical spine (C2-C7) with the pre-operative kyphotic alignment (Pre-OK) model and compared the biomechanical parameters (range of motion (ROM), annular stresses, nucleus stresses, and facet contact forces) for four decompression procedures at two levels (C3-C5); laminectomy (LN), laminoplasty (LP), posterior decompression with fusion (PDF), and anterior decompression with fusion (ADF). Pure moment with compressive follower load was applied to these models. PDF and ADF models' global ROM were 40% at C2-C7 less than the Pre-OK, LN, and LP models. The annular and nucleus stresses decreased more than 10% at the surgery levels for ADF, and PDF, compared to the Pre-OK, LN, and LP models. However, the annular stresses at the adjacent cranial level (C2-C3) of ADF were 20% higher. The nucleus stresses of the caudal adjacent level (C5-C6) of PDF were 20% higher, compared to other models. The PDF and ADF models showed a less than 70% decrease in the facet forces at the surgery levels, compared to the Pre-OK, LN, and LP models. The study concluded that posterior decompression, such as LN or LP, increases ROM, disc stress, and facet force and thus can lead to instability. Although there is the risk of adjacent segment disease (ASD), PDF and ADF can stabilize the cervical spine even for kyphotic alignments.

Influence of double rods and interbody cages on range of motion and rod stress after spinopelvic instrumentation: a finite element study.

To compare instrumentation configurations consisting of bilateral single or double rods and additional interbody cages (IBCs) at different levels in terms of Range of Motion (ROM) and distribution of von Mises stress in rods. A previously validated L1-pelvis finite element model was used and instrumented with configurations consisting of single or double bilateral rods and IBCs at multiple levels. Pure moments of 7.5N.m were applied to L1 in main directions in addition to a follower load of 280N. Global, segmental ROM and distribution of von Mises stress in rods were studied. All configurations reduced segmental and global ROM from 50 to 100% compared to the intact spine. Addition of IBCs slightly increased ROM at levels adjacent to the IBC placement. The simple rod configuration presented the highest von Mises stress (457MPa) in principal rods at L5-S1 in flexion. Doubling rods and IBC placement reduced this value and shifted the location of maximum von Mises stress to other regions. Among studied configurations, double rods with IBCs at all levels (L2-S1) showed the lowest ROM. Maximal von Mises stresses in secondary rods were lower in comparison to main rods. Double rods and IBCs reduced global and segmental ROM as well as von Mises stress in rods. The results suggest a possible benefit in using both strategies to minimize pseudarthrosis and instrumentation failure. However, increased ROM in adjacent levels and the shift of maximal von Mises stress to adjacent areas might cause complications elsewhere.

Mid-term follow-up outcomes of single-level cervical total disc replacement versus anterior cervical discectomy and fusion for the treatment of cervical disc degenerative disease.

To evaluate the clinical and radiographic results of cervical total disc replacement (CTDR) and anterior cervical discectomy and fusion (ACDF) in the treatment of single-level cervical disc degenerative disease with a mid-term follow-up period. Seventy-two patients with C5/6 single-level cervical degenerative disc disease refractory to conservative interventions were randomly assigned to two groups: ACDF and CTDR. Clinical outcomes were assessed by using the Japanese Orthopedic Association (JOA) score and the Neck Disability Index (NDI). Radiographic evaluations included range of motion (ROM), Cobb angles, heterotopic ossification (HO) and adjacent segment degeneration during follow-up. Sixty-nine patients (35 CTDR and 34 ACDF) were followed up over 4 years (mean 50.3 months). At 1 month postoperation, the NDI scores in CTDR patients were significantly higher than those in ACDF patients, especially in the work, driving and recreation aspects. There was significant improvement in global ROM in CTDR patients than in ACDF patients. The postoperative ROM of the C4/5 segment in ACDF patients increased significantly, and no significant difference was shown in other adjacent segments. The occurrence of HO was 42.9% (15/35) in the CTDR group at the last followup, with Grade I in 3 cases, Grade II in 11 cases and Grade III in 1 case. CTDR is an effective method in the treatment of single-level cervical disc degenerative disease. Compared to ACDF, CTDR is superior in the early improvement of quality of life, and restoration of segmental motion despite radiographic evidence of HO during a mid-term follow-up period.

Global Spine Range of Motion in Patients With Adolescent Idiopathic Scoliosis Before and After Corrective Surgery.

Given the importance of the spine in carrying out daily movements, adolescent idiopathic scoliosis (AIS) can significantly limit the range of motion (ROM). Severe forms of AIS are treated surgically, most commonly with posterior spinal fusion and instrumentation, which may also reduce spine ROM. This review is the first to describe the literature on total spine ROM in patients with AIS before and after corrective surgery. A systematic literature search was performed using PubMed and Google Scholar to identify articles reporting global spine ROM in AIS patients. Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), 486 articles were initially identified. Two independent reviewers (YM and JH) assessed eligibility for inclusion.A total of 11 articles fit the inclusion criteria. AIS in untreated patients seems to limit axial and coronal plane ROM based on the degree of curve severity, with more severe curves having less ROM. More research comparing total spine ROM in untreated AIS patients to that of healthy controls is needed. In those undergoing spinal fusions, the lowest instrumented vertebra and surgical approach appear to minimize further reductions in ROM; however, the findings are mixed. Vertebral body tethering (VBT) shows promising preliminary results in treating AIS while preserving motion; however, long-term outcomes have yet to be assessed for this novel procedure. The results of this systematic review suggest that further research is required before treatment strategies can be modified for surgically treating patients with AIS to take into account the effects of treatment on changes in spine mobility.

Developing a standardized curriculum for teaching chiropractic technique.

This is a report of the results of 4 facilitated workshops aimed at developing a standardized chiropractic technique curriculum. Workshops were held at research conferences during 2014, 2016, 2018, and 2019. Participants were tasked with developing recommendations for diagnostic and therapeutic procedures appropriate for chiropractic technique programs. For diagnostic procedures, there was general agreement among participants that chiropractic programs should include diagnostic imaging, postural assessment, gait analysis, palpation (static, motion, and joint play/springing), global range of motion, and evidence-based orthopedic/neurological tests. No consensus could be reached with respect to chiropractic x-ray line marking (spinography) nor heat sensing instruments, and there was only partial consensus on leg length assessment. For therapeutic procedures, all participants agreed that the following should be included: high-velocity, low amplitude spinal and extremity manipulation, adjustments assisted by hand-held instruments, drop tables, flexion-distraction tables, and pelvic blocks. There was unanimous support for teaching mobilization of the spine and peripheral joints, as well as for manual and instrument-assisted soft tissue therapies. There were some overarching issues: participants strongly preferred assessment methods known to be reliable and valid and therapeutic procedures known to be safe and effective. Where evidence was lacking, they insisted that diagnostic and therapeutic methods at minimum have face validity and biological plausibility. However, they cautioned against applying aspects of evidence-based care too rigidly. Despite differing views on chiropractic terminology, philosophy, and scope of practice, participants' opinions were similar regarding diagnostic and therapeutic procedures that ought to be included in chiropractic technique programs.