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Background: Minimally invasive hemilaminectomy is a safe and effective alternative to open laminectomy for treating intradural extramedullary tumors. There are no reports of postoperative kyphosis after this approach. This study aims to determine whether performing minimally invasive spine surgery hemilaminectomy for intradural extramedullary tumors can prevent the development of postlaminectomy kyphosis (PLK) or lordosis loss., Material and Methods: Sixty-five patients with spinal intradural extramedullary tumors who underwent minimally invasive hemilaminectomy surgery and complete pre and postoperative radiologic imaging were included. The effect of the surgical approach on the spinal sagittal axis was assessed by comparing pre- versus postoperative segmental and local Cobb angles at different spinal levels, considering anatomical localization (cervical, thoracic, lumbar, and transition segments) and functional features (mobile, semi-rigid, and transition segments), as well as the extent of the surgical approach (1, 2, or 3 levels) and follow-up., Results: None of the patients had an increase in thoracic kyphosis nor a loss of cervical or lumbar lordosis greater than or equal to 10° after undergoing the minimally invasive spine surgery hemilaminectomy approach. More than 5° of increase in kyphosis was detected on 7.4% and 11.1%, for the segmental and the local angles, respectively; meanwhile, for patients with loss of lordosis, this deviation was detected in 5.3%, for both angles. The occurrence of PLK was more common than that of lordosis loss, but mainly manifested in postoperative angle impairment of less than 5°. No significant differences were evidenced, considering the approach length., Conclusions: Hemilaminectomy represents a promising approach for preventing PLK and postlaminectomy lordosis loss following intradural extramedullary tumor resection., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Study Design/setting: Retrospective., Objective: Evaluate the surgical technique that has the greatest influence on the rate of junctional failure following ASD surgery., Summary of Background Data: Differing presentations of adult spinal deformity(ASD) may influence the extent of surgical intervention and the use of prophylaxis at the base or the summit of a fusion construct to influence junctional failure rates., Materials and Methods: ASD patients with two-year(2Y) data and at least 5-level fusion to the pelvis were included. Patients were divided based on UIV: [Longer Construct: T1-T4; Shorter Construct: T8-T12]. Parameters assessed included matching in age-adjusted PI-LL or PT, aligning in GAP-relative pelvic version or Lordosis Distribution Index. After assessing all lumbopelvic radiographic parameters, the combination of realigning the two parameters with the greatest minimizing effect of PJF constituted a good base. Good s was defined as having: (1) prophylaxis at UIV (tethers, hooks, cement), (2) no lordotic change(under-contouring) greater than 10° of the UIV, (3) preoperative UIV inclination angle<30°. Multivariable regression analysis assessed the effects of junction characteristics and radiographic correction individually and collectively on the development of PJK and PJF in differing construct lengths, adjusting for confounders., Results: In all, 261 patients were included. The cohort had lower odds of PJK(OR: 0.5,[0.2-0.9]; P =0.044) and PJF was less likely (OR: 0.1,[0.0-0.7]; P =0.014) in the presence of a good summit. Normalizing pelvic compensation had the greatest radiographic effect on preventing PJF overall (OR: 0.6,[0.3-1.0]; P =0.044). In shorter constructs, realignment had a greater effect on decreasing the odds of PJF(OR: 0.2,[0.02-0.9]; P =0.036). With longer constructs, a good summit lowered the likelihood of PJK(OR: 0.3,[0.1-0.9]; P =0.027). A good base led to zero occurrences of PJF. In patients with severe frailty/osteoporosis, a good summit lowered the incidence of PJK(OR: 0.4,[0.2-0.9]; P =0.041) and PJF (OR: 0.1,[0.01-0.99]; P =0.049)., Conclusion: To mitigate junctional failure, our study demonstrated the utility of individualizing surgical approaches to emphasize an optimal basal construct. Achievement of tailored goals at the cranial end of the surgical construct may be equally important, especially for higher-risk patients with longer fusions., Level of Evidence: 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: The purpose of this study was to assess the association between hip flexor length and pelvic tilt or lumbar lordosis by quantifying the effect of stretching on pelvic tilt and lumbar lordosis., Methods: We quantified pelvic tilt and lumbar lordosis before and after a single session of passive hip flexor stretching in a sample of 23 male participants. Changes in hip flexor length were also characterized, using a Thomas test protocol to measure passive hip extension in supine lying. We investigated both the mean effect of the stretching protocol and potential correlations between changes in passive hip extension and changes in pelvic tilt or lumbar lordosis., Results: Following the stretching protocol, there was a mean increase of 2.6° (P < .001) in passive hip extension and a corresponding mean reduction of 1.2° (P < .001) in anterior pelvic tilt. However, there was no change in lumbar lordosis, nor were there any meaningful correlations between change in passive hip extension and change in pelvic tilt or lumbar lordosis., Conclusion: The results suggest that hip muscle stretching may lead to immediate reductions in pelvic tilt during relaxed standing. Such stretching programs could play an important role in interventions designed to improve standing postural alignment., (Copyright © 2020. Published by Elsevier Inc.)

Background: Subsidence in anterior cervical corpectomy and fusion (ACCF) for cervical degenerative disease (CDD) are constantly observed during the postoperative course. Although kyphotic change of cervical alignment occurred frequently in cervical pyogenic spondylitis (CPS) postoperatively, studies on the postoperative change in segmental angle for CPS are limited. This study aimed to analyze cervical alignment after single-level ACCF using autologous bone graft without spinal instrumentation for CPS compared with that for CDD., Methods: Six patients underwent single-level ACCF using autologous bone graft without spinal instrumentation for CPS. The control group included 18 age-matched patients who underwent single-level ACCF using autologous bone graft for CDD without spinal instrumentation for the same duration. Cervical and lateral plain radiographs and computed tomography scans were taken. The Frankel classification was used to assess the neurological status preoperatively, postoperatively, and at 2-year follow-up for CPS., Results: At 2-year follow-up, the average segmental angle at the fusion level was - 12.2° ± 6.9° for CPS and - 5.2° ± 7.6° for CDD (p = 0.04). Changes in segmental angle at the fusion level were - 7.2 ± 9.0° for CPS and - 1.1° ± 7.1° for CDD (p = 0.02). At 2-year follow-up, the average anterior segmental fusion height was 23.4 ± 1.7 mm for CPS and 29.1 ± 5.1 mm for CDD (p < 0.001). At 2-year follow-up, bone fusion in the CPS group was classified as grade 5 (complete fusion) in 4 patients (66.7%) and grade 4 (probable fusion) in 2 (33.3%). In the CDD group, it was grade 5 in 13 patients (72.2%) and grade 4 in 5 patients (27.8%). Overall, both groups achieved 100% bone fusion rate. The Frankel classification in all CPS cases improved or leveled off., Conclusion: Progression of segmental kyphosis angle and subsidence of graft bone were observed postoperatively on all CPS cases. However, the neurological recovery and bone union were satisfactory.

Little attention has been given to factors which affects women running, such as proper footwear and breast support and their effects on spine. The objective of study was to analyse the influence of different breast support and footwear on vertebral posture during walking and running. Seventeen women (x¯ = 23.51; SD = 3.70 years) performed a treadmill walking (5 km/h) and running (7 and 10 km/h) with different footwear (barefoot, minimalist and traditional) and breast support (bare breast, everyday bra and sports bra) conditions. Spine movements were analyzed using three cameras in grayscale video mode, positioned behind the participant to register reflective markers fixed in the vertebrae. From the 3D coordinates of the trunk markers we computed, for the whole gait cycle (C) and for the average gait posture (neutral curve-NC) the maximal (M) thoracic (T) kyphosis and lateral flexion, and the maximal lumbar (L) lordosis and lateral flexion. Frontal plane: bare breast presented higher lumbar NC than the everyday bra and sports bra, higher MLC than the sports bra and lower MTC than the everyday bra and sports bra. Barefoot presented higher MTC than minimalist. Sagittal plane: bare breast presented lower MTC than the sports bra. Barefoot presented higher lumbar NC than the minimalist and traditional footwear and higher MLC than the minimalist and traditional ones. The sports bra increased curvatures in the thoracic spine that were rectified during bare breast conditions. In addition, both footwears were able to maintain the natural curvatures of the spine in the lumbar., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Pelvic incidence increases gradually throughout growth until skeletal maturity. Growing rod instrumentation has been suggested to have a stabilizing effect on the development of the normal sagittal spinal alignment. The purpose of this study is to determine the effect of fixed sagittal plane caused by dual growing rod instrumentation on the natural progression of sagittal spinopelvic parameters in children with idiopathic or idiopathic-like early onset scoliosis., Methods: Hospital records of children with growing rod instrumentation from 4 separate institutions were reviewed retrospectively. Inclusion criteria were idiopathic or idiopathic-like early onset scoliosis, treatment with dual growing rods with lower instrumented vertebra L4 or upper and more than 2 years of follow-up. Instrumentation levels, magnitudes of major curve, thoracic kyphosis (T2-T12), lumbar lordosis (L1-S1) and pelvic incidence were recorded from preoperative and postoperative standing whole-spine radiographs. Estimated pelvic incidence was also calculated for each patient as if their spines had not been instrumented using the previous normative data., Results: A total of 37 patients satisfied the inclusion criteria. Average age at initial surgery was 7.4±1.8 years (range, 4 to 12 y). Mean follow-up time was 71±26 months (range, 27 to 120 mo). Mean preoperative Cobb angle of 59±13.5 (range, 30 to 86) degrees was reduced to 35.1±17.5 (range, 11 to 78) degrees at the last follow-up. Mean preoperative T2-T12 kyphosis angle was 46.2±14.9 degrees (range, 22 to 84 degrees). At the latest follow-up, it was 44.8±16.2 degrees (range, 11 to 84 degrees) (P=0.93). Mean L1-S1 lordosis angle was 50.5±10.7 degrees (range, 30 to 72 degrees) preoperatively. At the latest follow-up, mean L1-S1 lordosis angle was 48.8±12.7 degrees (range, 26 to 74 degrees) (P=0.29). Mean preoperative pelvic incidence was 45.7±7.9 degrees (range, 30 to 68 degrees). At the latest follow-up, it was 46.7±8.4 degrees (range, 34 to 72 degrees) (P=0.303). The estimated average pelvic incidence was 49.5 degrees (P=0.012)., Conclusions: Previously reported developmental changes of the sagittal spinal parameters were not observed in children who underwent posterior spinal instrumentation. Our findings suggest that spinal instrumentation impedes the natural development of the sagittal spinal profile., Level of Evidence: Level IV-this is a retrospective case-series.

Background: Clinical studies have shown altered sexual function in people with diabetes; basic science studies, using the streptozotocin (STZ)-induced animal model of type 1 diabetes mellitus (DM1), have consistently reported decreased sexual behavior in hyperglycemic female animals, but features of sexual motivation and aggressive behavior have not been explored in these animals., Aim: To study several parameters that denote sexual motivation in STZ-treated female rats and to compare behavioral features of sexual behavior and aggression in non-paced mating (NPM) and paced mating (PM) conditions., Methods: DM1 was induced by injecting STZ (diluted in citrate buffer) at a dose of 50 mg/kg intraperitoneally over 2 consecutive days into ovariectomized Wistar rats. 10 days later, female rats were treated with estradiol benzoate (10 μg, -24 hours) and progesterone (3 mg, -4 hours); their sexual behavior (including lordosis quotient, lordosis intensity, and proceptivity) and aggression were evaluated under NPM and PM conditions. Body weight, blood glucose levels, and spontaneous ambulatory activity also were measured. A group of STZ-treated animals was administered a long-acting insulin analogue (glargine) every 12 hours for 8 days, and their sexual and aggressive behaviors were evaluated in NPM., Outcomes: We quantified body weight, blood glucose level, spontaneous ambulatory activity, and sexual and aggressive behaviors in NPM and PM; the time the female rats spent interacting with the male rat or in the male rat's chamber also was registered in PM., Results: Compared with controls, STZ-treated ovariectomized rats lost body weight, had increased blood glucose levels, and had unchanged spontaneous ambulatory activity. In the PM and NPM conditions, animals showed decreased lordosis quotient and lordosis intensity, increased aggression, and unaltered proceptivity, although in NPM the effects of STZ treatment on aggression were more drastic and were completely prevented by insulin. In PM no differences were found between diabetic and control female rats in the time interacting with the male rat or in the male rat's chamber., Clinical Translation: These findings support the observation of increased prevalence of sexual dysfunctions and aggression in the clinical setting of DM1., Strengths and Limitations: The main strength of this study is that it analyzed sexual behavior under PM and NPM conditions and aggression in STZ-treated female rats. Its main limitations are that the model of DM1 represents only 10% of the affected population and that no specific treatment is proposed for the sexual dysfunctions., Conclusion: These results suggest that STZ-treated rats have decreased sexual receptivity in NPM and PM, accompanied by increased aggressiveness in NPM. Hernández-Munive AK, Rebolledo-Solleiro D, Ventura-Aquino E, Fernández-Guasti A. Reduced Lordosis and Enhanced Aggression in Paced and Non-Paced Mating in Diabetic Female Rats. J Sex Med 2018;15:124-135., (Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.)

Prolonged standing is common in many occupations and has been associated with low back discomfort (LBD). No recent studies have investigated a footrest as an intervention to reduce LBD associated with prolonged standing. This study investigated the effect of a footrest on LBD and sought to determine if LBD changes were accompanied by changes in muscle fatigue and low back end-range posture and movement. Twenty participants stood for two 2-h trials, one with and one without a footrest. LBD, lumbar erector spinae electromyography, upper lumbar (UL) and lower lumbar (LL) angles were measured. A significant increase in LBD occurred in both conditions but the footrest did not significantly decrease LBD. The only significant finding between conditions was that UL lordosis became more similar to usual standing over time with footrest use. These findings suggest that footrest use may not reduce LBD development and that development of LBD with prolonged standing is unlikely to be due to muscle fatigue or end-range posture mechanisms., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: To date, no study had reported the phenomenon of deteriorated postoperative cervical tilt in Lenke type 2 adolescent idiopathic scoliosis patients. The purpose of this study is to evaluate the cervical tilt in Lenke type 2 adolescent idiopathic scoliosis patients with right-elevated shoulder treated by either full fusion or partial/non fusion of the proximal thoracic curve., Methods: A total of 30 Lenke type 2 AIS patients with preoperative right-elevated shoulder underwent posterior spinal instrumentation from 2009 to 2011 were included in this study. All the subjects were divided into 2 groups according to the selection of upper instrumented vertebra. There were 14 cases proximally fused to T1 or T2 (Group A) and 16 cases proximally fused to T3 or below (Group B). Both standing anteroposterior and sagittal X-ray films of the spine obtained preoperatively, one week after the operation, and at a minimum of two-year follow-up were analyzed with respect to the following parameters: cervical tilt, T1 tilt, proximal thoracic Cobb angle, main thoracic Cobb angle, apical vertebral translation of proximal thoracic curve, apical vertebral translation of main thoracic curve, radiographic shoulder height, cervical lordosis, proximal thoracic kyphosis and main thoracic kyphosis., Results: Most (83.3%) of the patients in these two groups gained satisfactory shoulder balance after surgery. However, the cervical tilt significantly improved in group A (p < 0.001) but deteriorated in group B (p < 0.001). In group A, the decrease of cervical tilt significantly positively correlated with that of T1 tilt (p < 0.001). In group B, the increase of cervical tilt significantly positively correlated with both the increase of T1 tilt (p < 0.001) and the increase of apical vertebral translation of proximal thoracic curve (p < 0.05)., Conclusions: Lenke type 2 AIS patients with right-elevated shoulder gain improved shoulder but deteriorated cervical tilt after partial/non fusion of proximal thoracic curve. Full fusion of proximal thoracic curve helps to prevent the residual cervical tilt in these patients.

Study Design: Retrospective study., Objective: To evaluate long-term effectiveness of central hook-rod constructs for posterior spinal osteotomy closure., Summary of Background Data: During osteotomy site closure various techniques are used, including patient positioning, rod cantilevering, extending fixation points, and compressing through pedicle fixation points. All add premature stress on fixation points and may lead to loosening/eventual fixation failure. To avoid this, we often use a central compression hook-rod construct for osteotomy closure., Methods: Fifty-six consecutive patients with fixed sagittal imbalance were treated with multilevel posterior column osteotomies (N = 19), pedicle subtraction osteotomy (N = 31), or vertebral column resection (N = 6). All 56 patients had undergone osteotomy closure using central compression hook-rod constructs and were analyzed at a follow-up of 5 years or more. Compression hooks were inserted into the fusion mass or lamina above/below the osteotomy and centrally attached to a short rod connected to pedicle screw-based rods via a cross-link. Diagnoses included sagittal imbalance associated with scoliosis (N = 39), degenerative sagittal imbalance (N = 14), ankylosing spondylitis (N = 2), and Scheuermann's kyphosis (N = 1). There were 55 revision cases and 1 primary. Radiographic/clinical analysis was performed to evaluate the efficacy/complications of this technique., Results: Overall lumbar lordosis increased an average of 31.7° and local lordosis through the osteotomy site increased an average of 29.3°. Sagittal balance improved by an average of 92 mm. In all cases, osteotomy closures were performed without screw loosening or loss of correction intraoperatively. At a follow-up of 5 years or more, no failures of the hook-rod construct were seen, but there were 3 patients with partial implant failure; however, no symptomatic pseudarthroses at the osteotomy sites occurred. Seven patients developed pseudarthrosis below the central hook-rod construct., Conclusion: A central hook-rod construct is safe, controlled, and effective for applying compressive forces to close various spinal osteotomies without fixation failure or pseudarthrosis at the osteotomy site noted at a follow-up of 5 or more years. It adds fixation strength to the overall construct avoiding undue stress on pedicle screws., Level of Evidence: 3.

Study Design: Retrospective radiographical analysis of cervical and thoracolumbar sagittal alignment in young adults with idiopathic scoliosis., Objective: To analyze cervical alignment types, the relationship between cervical and thoracolumbar alignment and the effect of posterior instrumentation., Summary of Background Data: Thoracic scoliosis with hypokyphosis may decrease cervical lordosis. Additional adaptive positional changes of the mobile cervical segment may exist, because sigmoid cervical patterns are observed. Sagittal alignment of the instrumented thoracolumbar spine may influence cervical alignment., Methods: Pre- and postoperative full-spine radiographs of 52 patients were analyzed at 8-year average follow-up. Sagittal thoracolumbar measurements were T1 slope, T1-T4 kyphosis, T4-T12 kyphosis, L1-S1 lordosis, pelvic incidence, pelvic tilt, sacral slope, sagittal vertical axis (SVA) C7, and SVA C2. Cervical measurements were C0-C2, C2-C6, C2-C4, C4-C6, and C2-T1 lordosis, chin-brow vertical angle., Results: Five cervical alignment types were identified: lordotic, hypolordotic, kyphotic, sigmoid with cranial lordosis, and sigmoid with cranial kyphosis. Spinopelvic parameters and global thoracolumbar balance remained unchanged postoperatively. The average C2-C6 lordosis increased by 6.4° (P < 0.0001). Twenty-seven of the 52 patients changed cervical alignment postoperatively. SVA C2-C7 difference changed in this subgroup (P = 0.0159). In 21 of the 27 patients, SVA changed more than 5 mm at C2 (P = 0.0029), and in 25 of the 27 patients at C7 (P < 0.0001). A correlation existed between T4-T12 kyphosis and L1-S1 lordosis, C2-C4 and L1-S1 lordosis, L1-S1 lordosis, and pelvic tilt. T1-T4 kyphosis and T1 slope correlated with C2-T1 lordosis, but proximal junctional kyphosis was not linked to a specific cervical alignment type., Conclusion: Postoperative adaptive changes occurred at C7 and C2 by shifting anteriorly or posteriorly, resulting in different radiographical cervical shapes. The amount of lumbar lordosis may influence cervical lordosis, which needs to be considered for surgical correction. Adaptive hip movements may influence thoracolumbar and cervical alignment. The amount of proximal thoracic kyphosis influenced cervical lordosis. Global thoracic hypokyphosis might influence cervical alignment, but it was not evidenced., Level of Evidence: 4.

Sexual receptivity in the female rat is dependent on dose and duration of estradiol exposure. A 2 μg dose of estradiol benzoate (EB) primes reproductive behavior circuits without facilitating lordosis. However, 50 μg EB facilitates lordosis after 48 hours. Both EB doses activate membrane estrogen receptor-α (mERα) that complexes with and signals through metabotropic glutamate receptor-1a (mGluR1a). This mERα-mGluR1a signaling activates a multisynaptic lordosis-inhibiting circuit in the arcuate nucleus (ARH) that releases β-endorphin in the medial preoptic nucleus (MPN), activating μ-opioid receptors (MOP). MPN MOP activation is maintained, inhibiting lordosis for 48 hours by 2 μg EB, whereas 50 μg EB at 48 hours deactivates MPN MOP, facilitating lordosis. We hypothesized that 50 μg EB down-regulates ERα and mERα-mGluR1a complexes in the ARH to remove mERα-mGluR1a signaling. In experiment I, 48 hours after 2 μg or 50 μg EB, the number of ARH ERα-immunopositive cells was reduced compared with controls. In experiment II, compared with oil controls, total ARH ERα protein was decreased 48 hours after 50 μg EB, but the 2 μg dose was not. These results indicate that both EB doses reduced the total number of cells expressing ERα, but 2 μg EB may have maintained or increased ERα expressed per cell, whereas 50 μg EB appeared to reduce total ERα per cell. In experiment III, coimmunoprecipitation and Western blot revealed that total mERα and coimmunoprecipitated mERα with mGluR1a were greater 48 hours after 2 μg EB treatment vs rats receiving 50 μg EB. These results indicate 2 μg EB maintains but 50 μg EB down-regulates mERα-mGluR1a to regulate the lordosis circuit activity.

The purpose of this study was to evaluate the influence of different implant designs of total lumbar disc replacements on the segmental biomechanics of the lumbar spine. The unconstrained Charité, the semi-constrained Prodisc and a semi-constrained Prototype with more posterior centre of rotation than the Prodisc were tested in vitro using six human, lumbar spines L2-L5. The segmental lordosis was measured on plain radiographs and the range of motion (ROM) for all six degrees of freedom with a previously described spine tester. All prostheses were implanted at level L3-L4. Compared with the intact status all prostheses resulted in a significant increase of segmental lordosis (intact 5.1°; Charité 10.6°, p = 0.028; Prodisc 9.5°, p = 0.027; Prototype 8.9°, p = 0.028), significant increase of flexion/extension (intact 6.4°, Charité 11.3°, Prodisc 12.2°, Prototype 12.2°) and axial rotation (intact 1.3°, Charité 5.4°, Prodisc 3.9°, Prototype 4.2°). Lateral bending increased significantly only for the Charité (intact 7.7°; Charité 11.6°, p = 0.028; Prodisc 9.6°, Prototype 9.8°). The segmental lordosis after Prototype implantation was significantly lower compared with Charité (p = 0.024) and Prodisc (p = 0.044). No significant difference could be observed for segmental lordosis between Charité and Prodisc and for ROM between the two semi-constrained prosthesis Prodisc and Prototype. The axial rotation for the unconstrained Charité was significantly higher than for the semi-constrained prosthesis Prodisc and Prototype, flexion/extension and lateral bending did not differ. Summarizing, the unconstrained prosthesis design increased segmental lordosis and showed a tendency towards higher ROM for axial rotation/lateral bending and lower ROM for flexion/extension than a semi-constrained prosthesis. A more anterior centre of rotation in a semi-constrained prosthesis resulted in a higher increase of segmental lordosis after TDR than a semi-constrained prosthesis with more posterior centre of rotation. The location of the centre of rotation in a semi-constrained prosthesis did not alter the magnitude of ROM. Despite the different alterations of ROM and segmental lordosis due to implant design, these differences were negligible compared with the overall increase of ROM and segmental lordosis by the implantation of a TDR compared with the physiologic state.

Objective: We hypothesized that L5-S1 kinematics will not be affected by the lordosis distribution between the prosthesis endplates., Materials and Methods: Twelve cadaveric lumbosacral spines (51.3 ± 9.8 years) were implanted with 6° or 11° prostheses (ProDisc-L) with four combinations of superior/inferior lordosis (6°/0°, 3°/3°, 11°/0°, 3°/8°). Specimens were tested intact and after prostheses implantation with different lordosis distributions. Center of rotation (COR) and range of motion (ROM) were quantified., Results: Six-degree lordosis prostheses (n = 7) showed no difference in flexion-extension ROM, regardless of design (6°/0° or 3°/3°) (p > 0.05). In lateral bending (LB), both designs reduced ROM (p < 0.05). In axial rotation, only the 3°/3° design reduced ROM (p < 0.05). Eleven-degree lordosis prostheses (n = 5) showed no difference in flexion-extension ROM for either design (p > 0.05). LB ROM decreased with distributed lordosis prostheses (3°/8°) (p < 0.05). Overall, L5-S1 range of motion was not markedly influenced by lordosis distribution among the two prosthesis endplates. The ProDisc-L prosthesis design where all lordosis is concentrated in the superior endplate yielded COR locations that were anterior and caudal to intact controls. The prosthesis with lordosis distributed between the two endplates yielded a COR that tended to be closer to intact., Conclusions: Further clinical and biomechanical studies are needed to assess the long-term impact of lordosis angle distribution on the fate of the facet joints.

Introduction: Cervical degenerative pathology can produce pain and disability and, in case of failure of conservative treatment surgery is indicated., Materials and Methods: 107 patients affected by single level cervical degenerative pathology were surgically treated by Cloward procedure. On radiographs, the sagittal segmental alignment (SSA) of the affected level and sagittal alignment of the cervical spine were measured., Results: Preoperatively, mean SSA was 0.6° and at the last follow-up 1.8°. In particular, adjacent-level degeneration occurred more frequently in Group A than in Group B., Conclusion: Lordotic SSA angle can be considered a protective factor against adjacent-level degeneration.

Unlabelled: The aim of this research was to evaluate posture types in children aged 7-12 from rural environment., Materials and Methods: This study was conducted among 562 children from Podkarpackie and Swietokrzyskie region. Evaluation of posture was studied by photogrammetry method with the use of projection moire phenomenon., Results: The most common type of posture was lordosis (44.84%), then kyfosis (37.19%) and balanced type (17.97%):, Conclusion: Early diagnosis of posture defects allows their correction and undertaking early prophylactic actions.

Background: Preservation of segmental motion and avoidance of adjacent segment degeneration are common theoretical advantages of cervical arthroplasty and ACF. In patients with unilateral cervical radiculopathy, both procedures have shown good clinical results; but there are currently no proven comparative biomechanical results. This study was designed to compare the biomechanical effect of cervical arthroplasty and ACF and to propose optimal inclusion criteria for each surgery., Methods: Among the patients with unilateral cervical radiculopathy, 15 patients who underwent arthroplasties using the Bryan disk (Medtronic Sofamor Danek, Memphis, TN) and 13 patients who underwent ACFs were retrospectively analyzed. A radiological assessment and comparative analysis of the biomechanical results (sagittal alignment, ROM, and disk height) between the 2 procedures were performed., Results: Both procedures showed similar but contrary biomechanical results, with the exception of the disk height. Anterior cervical foraminotomy has been shown to restrict motion in the segmental and adjacent segment motion and a tendency toward restoration of lordosis. Anterior cervical foraminotomy caused a significant decrease in disk height after surgery, whereas arthroplasty caused no change in height. The restoration of disk height was achieved by arthroplasty, especially in patients with spondylotic radiculopathy., Conclusions: In unilateral cervical radiculopathy, arthroplasty and ACF provided favorable clinical and radiological outcomes. However, we should understand the different biomechanical backgrounds resulting in common advantages. To achieve the fundamental goal of the procedures, the patients' biomechanical abnormalities should be elucidated and treated by the optimal procedure.

Objective: The main mechanism of injury to the spine is torsion especially when coupled with compression. In this study, the in vitro torsional stiffness of the lumbar spine segments is compared in flexion and extension positions by cyclic and failure testing., Methods: Fifteen lumbar spines were sectioned from fresh cadavers into 15 L2/3 and 15 L45 motion segments. Each vertebral segment was then potted superiorly and inferiorly in polymethylmethacrylate, effectively creating a bone-disk-bone construct. The potted spinal segments were mounted in a mechanical testing system, preloaded in compression to 300 N, and axially rotated to 3 degrees in both directions at a load rate of 1 degrees /s. This was done over 3 cycles for each motion segment in the flexion and extension positions. Each specimen was then tested to torsional failure in either flexion or extension. Stiffness, torque, and energy were determined from cyclic and failure testing., Results: The results showed that in all cases of cyclic testing, the higher segment extension resulted in higher torsional stiffness. In relative extension, the lumbar specimens were stiffer, generated higher torque values, and generally absorbed more energy than the relative flexion condition. There were no differences found in loading direction or failure testing., Conclusions: Increasing the effective torsional stiffness of the lumbar spine in extension could provide a protective mechanism against interverbral disk injury. Restoration of segmental extension through increasing the lumbar lordosis may decrease the strain and reinjury of the joints, which can help reduce the extent of pain in the lumbar spine.

Introduction: The harmful effects of sustained sitting and the health of the spine are well documented. The focus of much of this investigation has been sedentary occupations. However, how people sit during leisure hours can impact on the health of the spine both in and out of working hours., Methods: A literature search was conducted using Amed, Cinahl and OVID Medline databases. Papers published between 1985 and 2007 were selected for review. These included epidemiological and experimental studies that explored the relationships between seated postures and health of the lumbar spine. Until recently there was confusion in the scientific literature as to which seated postures were least harmful: lordosed or kyphosed. This article reviews and analyses these conflicts in relation to leisure sitting., Results: Analysis of the literature demonstrates that kyphosed seated postures when sustained are more harmful to the health of the lumbar spine than lordosed seated postures. There is a misconception amongst designers and users of leisure seating that kyphosed relaxed postures are comfortable and that comfort equates with health. It is argued that sustained kyphosed postures are insidiously harmful to the spine in that they may contribute to disc degeneration in the absence of pain. Sustained kyphosed postures also adversely affect spinal ligaments, muscles and joints and lead to neuromuscular and cumulative trauma disorders and loss of spinal stability., Conclusion: Recent research demonstrates that postures popularly assumed in recreational or leisure seating lead to cumulative damage to soft tissues of the spine. These effects may still be present at the commencement of the following work day. In the prevention of work disability caused by sustained sitting, health professionals must consider the impact of leisure seating design and recreational sitting behaviour.

Unlabelled: Study was aimed to determine the incidence of postural faults, level of physical activity and their possible relationship in young adults. Material included 100 subjects recruited randomly among students of Medical University of Silesia (54F aged 20-28, mean=22.9, SD=2.11 and 46M aged 20-29, mean=25.1, SD=1.86). Posture was examined according to modified Klapp protocol. For thoracic kyphosis and lumbar lordosis, values of 30 degrees +/-2 were considered as normal. ATR exceeding 5 degrees was considered as scoliosis. Physical activity was evaluated with a questionnaire, admitting 1 point for each hour of physical labour and 2 points for each hour of sport activity per week. Statistical analysis was based on the one-way ANOVA test. Postural faults were widespread in assessed group. Most common was lumbar hypolordosis (71.0%, 48.1%F and 97.8%M) and thoracic hyperkyphosis (58.0%, 53.7%F and 63.0%M). Scoliosis was observed in 54.0% (50%F and 58.7%M). Physical activity in assessed group was high, with 71% of cases (76%F and 62.5%M) within range of mean value +/- 1SD. Level of activity in men was significantly higher than women (mean 20.25 vs. 6.28 points, p<0.05). Significant dependence of postural faults and physical activity was not observed., Conclusions: Young adults prefer active way of life. Postural faults are widespread among young adults. Correlation between level of physical activity and postural faults was not observed.

Study Design: Prospective clinical study., Objective: To evaluate the clinical and radiographic result of the transforaminal lumbar interbody fusion (TLIF) as an alternative new technique in degenerative and isthmic lower grade spondylolisthesis., Summary of Background Data: TLIF is a new alternative surgical technique used for spinal fusion avoiding the ventral approach and can theoretically prevent typical complications, such as those seen in anterior and posterior lumbar interbody fusion., Materials and Methods: There were 19 degenerative, 19 isthmic, and 1 dysplastic spondylolistheses operated on with TLIF. The clinical follow-up used the Oswestry Disability Index, the radiologic follow-up radiograph, analyzing segmental lordosis, intervertebral space, reduction, and fusion rate. The minimum follow-up was 24 months, mean clinical follow-up was 50 months, and radiologic follow-up was 35 months., Results: The medium of the Oswestry Disability Index in all patients decreased from 23.5 to 13.5 points, in isthmic spondylolistheses from 20.5 to 10.95 after 2 years. The radiographic fusion rate was 94.8%. The sagittal translation was reduced from 23% to 15%. There were 3 (7.6%) serious postoperative complications observed, which required operative revision., Conclusions: TLIF is a safe and effective method to treat low-grade spondylolisthesis, which can theoretically prevent typical complications of anterior and posterior lumbar interbody fusion. The results of isthmic spondylolistheses were significantly better compared to degenerative spondylolistheses.

Background Context: Although posterior lumbar interbody fusion (PLIF) for degenerative lumbar diseases is routine, there are few reports on double-level PLIF., Purpose: To evaluate the clinical outcomes of double-level PLIF., Study Design/setting: A retrospective study of operated cases in Gifu, Japan., Patient Sample: Nineteen patients (8 men and 11 women, 59.5+/-10.2 years) who underwent double-level PLIF between 1996 and 2001., Outcome Measures: Operation time, blood loss, complications, the Japanese Orthopaedic Association (JOA) score for back pain and lumbar sagittal alignment were evaluated., Methods: Patients were examined retrospectively at follow-ups of 3.6+/-1.7 years. Primary diseases were spondylolisthesis, spinal canal stenosis, degenerative scoliosis and herniated intervertebral disc. Fusion areas were L3 to L5 in 15 cases and L4 to S1 in 4 cases., Results: The mean JOA score increased from an initial score of 12.9+/-3.5 to 21.3+/-4.9 at the final follow-up. There was a positive correlation (R=0.718, p<.001) between the increase in lordotic angle and the increase in the JOA score. Several parameters suggested that the surgical invasiveness was not minimal., Conclusion: Double-level PLIF provided satisfactory results and preserved lumbar spine lordosis.

Background: One of the goals of total lumbar disc replacement is restoration of the physiological sagittal alignment. There is little evidence if this goal is reached in vivo and further affects the clinical outcome., Methods: In 29 patients segmental lordosis and total lumbar lordosis were measured on X-rays pre- and postoperatively. The functional outcome was evaluated prospectively with the Visuell Analogue Scale, Oswestry Low Back Pain Disability Questionnaire and Short Form 36 Health Survey Questionnaire., Findings: Total disc replacement increased segmental lordosis significantly while total lumbar lordosis remained unchanged. Preoperative segmental/total lumbar lordosis was physiological in 52%/91% of the patients. Postoperatively these values changed to 72% for segmental- and 94% for total lumbar lordosis. No difference could be observed in clinical outcome measures in patients with physiological and unphysiological segmental lordosis., Interpretation: Monosegmental total disc replacement increases the segmental lordosis in most of the cases while preserving the total lumbar lordosis which produces a decrease of lordotic angle in the adjacent segment(s). Although short term clinical results are not affected, the segmental lordosis increase and adjacent segment(s) alteration may influence long term outcome.

Radiographic factors that correlate with outcome following long posterior fusion to L5 for adult scoliosis were investigated. Measurement of thoracic, lumbar, and fractional lumbosacral curves, L5 obliquity, lumbar and L5-S1 lordosis, coronal balance, sagittal balance, and L5-S1 disc height were performed on preoperative, postoperative, and follow-up 36-in posteroanterior/lateral radiographs. Of 16 patients, 14 were female (88%) and 2 male (12%). Average follow-up was 32 months (8-78 months). Scoliotic curves demonstrated stable corrections; however, lumbar and L5-S1 lordosis decreased and sagittal decompensation worsened. Ten patients (62%) had no evidence of transitional degeneration. Six patients (38%) had radiographic evidence of L5-S1 degeneration, and three (19%) underwent revision. Patients with good preoperative sagittal balance, preserved lumbar lordosis, good postoperative fractional curve correction, and L5-S1 disc height preservation are most likely to benefit from posterior fusion to L5, avoiding sacral fusion, for adult scoliosis.

The best knowledge on seated posture before the Enlightenment was not scientific, but influenced by sociocultural, economic, and manufacturing factors. Although the pursuit of knowledge related to spinal postural health was advanced with the advent of empirico-analytic research, academic opinion continued to be influenced by unsubstantiated information, often resulting in incorrect advice to the public. Only in the past decade has advice on "correct" seated posture, spanning the time from the Hippocratic texts to the present, been brought into question by evidence-based research. By exploring seating from 3100 B.C to the present, this article discusses key influences that have an impact on seating functional to spinal postural health. Emphasis is placed on the role of medical opinion.

It is common practice to place a pillow or bolster under the knees of patients undergoing lumbar spine CT or MRI. The use of such supportive cushions leads to gentle hip flexion that is thought to ease pain and "reduce lumbar lordosis". It is also thought to facilitate axial imaging through the discs. Observations in seven subjects who underwent lumbar spine MRI with and without such hip flexion showed no appreciable change in the degree of lordosis. As the use of such devices does not produce a practical reduction of lumbar lordosis, the decision to employ them should be made entirely with respect to patient comfort.

Aim: To determine through the measurement of different angles the correction of lumbar hyperlordosis after bilateral femoral lengthening using the Icatme technique and to assess the absence of neurological symptomatology secondary to stenosis of the lumbar canal after femoral lengthening., Patients and Methods: Thirty-four patients with achondroplasia were studied. Mean age was 22.3 years. The patients underwent femoral lengthening using the Icatme technique. X rays of the lateral rachis taken before and after lengthening were used to measure a series of angles., Results: The lumbar lordosis angle, Sez's angle and the L5S1 angle decreased while the lumbosacral angle, Jungham's angle and the sacrum angle increased, leading to correction of lumbar hyperlordosis, verticalization of the sacrum and improvement in thoracolumbar and lumbosacral inflection. Values were similar to the standard for individuals without achondroplasia., Conclusions: Femoral lengthening using the Icatme technique in achondroplastics modifies the statics of the lumbar spine, making them similar to those of nonachondroplastics. The procedure corrects lumbar hyperlordosis and prevents the appearance of neurological symptomatology due to stenosis of the lumbar canal. The incidence of neurological complications due to stenosis of the lumbar canal in achondroplastics who have undergone femoral lengthening is low compared with that of achondroplastics of the same age and sex who have not undergone this procedure.

Objective: To develop a new sitting spinal model and an optimal driver's seat by using review of the literature of seated positions of the head. spine, pelvis, and lower extremities., Data Selection: Searches included MEDLINE for scientific journals, engineering standards, and textbooks. Key terms included sitting ergonomics, sitting posture, spine model, seat design, sitting lordosis, sitting electromyography, seated vibration, and sitting and biomechanics., Data Synthesis: In part I, papers were selected if (1) they contained a first occurrence of a sitting topic, (2) were reviews of the literature, (3) corrected errors in previous studies, or (4) had improved study designs compared with previous papers. In part II, we separated information pertaining to sitting dynamics and drivers of automobiles from part 1., Results: Sitting causes the pelvis to rotate backward and causes reduction in lumbar lordosis, trunk-thigh angle, and knee angle and an increase in muscle effort and disc pressure. Seated posture is affected by seat-back angle, seat-bottom angle and foam density, height above floor, and presence of armrests., Conclusion: The configuration of the spine, postural position, and weight transfer is different in the 3 types of sitting: anterior, middle, and posterior. Lumbar lordosis is affected by the trunk-thigh angle and the knee angle. Subjects in seats with backrest inclinations of 110 to 130 degrees, with concomitant lumbar support, have the lowest disc pressures and lowest electromyography recordings from spinal muscles. A seat-bottom posterior inclination of 5 degrees and armrests can further reduce lumbar disc pressures and electromyography readings while seated. To reduce forward translated head postures, a seat-back inclination of 110 degrees is preferable over higher inclinations. Work objects, such as video monitors, are optimum at eye level. Forward-tilting, seat-bottom inclines can increase lordosis, but subjects give high comfort ratings to adjustable chairs, which allow changes in position.

Using a realistic nonlinear three-dimensional finite element model, biomechanics of the entire lumbar spine L1-S1, risk of tissue injury, and required local lumbar muscle exertion in extended and flexed postures are investigated under moderate to relatively large compression loads as great as 2800 N as the lumbar lordosis is altered from the undeformed value of -46 degrees by + 15 degrees in extension or by as much as 38 degrees in flexion. To prevent the instability of the passive structure in compression, the changes in segmental rotations are prescribed and the required sagittal/lateral moments at each level calculated. The effect of load distribution is considered by applying the whole compression on the L1 vertebra alone or among all vertebral levels with 90% or 80% of the compression on the L1 and the remaining evenly shared by the rest. The results are markedly affected by the postural changes and load distributions. The primary global displacement responses are stiffened in the presence of combined loads. The axial compression load substantially increases the intradiscal pressure, facet loads, and disc fiber strains. The large facet loads at the caudal L5-S1 level causes large differential sagittal rotations at vertebral posterior and anterior bony structures, resulting in large stresses in the pedicles and pars interarticularis. The contribution of the passive structures in carrying the load is influenced by the lumbar lordosis and compression load magnitude. Slight flattening of the lumbar spine under large compression reduces the maximum disc fiber strains and required equilibrating moments without adversely affecting the disc pressure and ligament forces. During lifting tasks, the passive spinal structures are protected by slight to moderate flattening in the lumbar curvature, whereas larger flexion angles impose significantly higher risk by increasing the disc pressure, disc anulus fiber strains, ligamentous forces, and facet forces. Changes in lordosis also markedly affect the stabilizing sagittal moments; the required moments diminish in small flexion angles, thus requiring smaller forces in local lumbar muscles. Thus, the lumbar posture during heavy lifting could be adjusted to minimize the required moments generated by lumbar muscle exertions and the risk of tissue injury.

Study Design: This experimental study was designed to test the hypothesis that posterior spinal fusion and internal fixation, using a stiff transpedicular construct, would withstand additional anterior column growth without the need for an anterior procedure and would prevent the development of deformity secondary to asymmetric growth of the anterior column in the immature canine model., Objectives: This model revealed that a mechanical epiphysiodesis of the anterior spinal column can be created through a posterior approach in an immature growing animal using a stiff transpedicular construct. These results were correlated to the crankshaft mechanism clinically to provide a possible rationale for transpedicular posterior spinal instrumentation and fusion, without a concomitant anterior procedure, in immature patients., Summary of Background Data: All operative immature canines underwent posterior fusion of L1-L5 vertebral bodies with autogenous iliac crest bone graft. Instrumented canines underwent the additional placement of transpedicular screws at L1, L3, and L5 as well as 3/16-inch rods and a transverse connector. Previous studies have revealed that continued anterior spinal column growth after posterior arthrodesis causes a resultant deformity in quadrupeds. No previous study has assessed whether a transpedicular construct can overpower the anterior spinal growth plate in an immature growing model., Methods: Twenty-five skeletally immature canines were randomized into four groups: control, fusion only, screw and fusion, and instrumentation and fusion. Disc space growth, vertebral body growth, and sagittal plane angulation were the variables analyzed. Management response variables were visualized graphically and radiographically., Results: Posterior tethering and anterior column growth occurred in the noninstrumented fusion groups, producing substantial lordosis. Anterior column growth was arrested in the instrumented canines as demonstrated by decreased vertebral body length, disc space narrowing, and, most importantly, prevention of lordosis., Conclusions: The present study confirmed that in immature canines anterior column growth continues after posterior fusion without instrumentation. The magnitude of this growth, combined with a posterior tether, is sufficient to cause significant lordosis. The results are the first to document that a stiff posterior spinal instrumentation system is sufficient to overpower the residual anterior growth centers, even in the presence of a posterior tether (fusion mass). This technique creates a mechanical epiphysiodesis evidenced by arresting vertebral body length, narrowing disc space, and preventing lordosis, thus thwarting the deformity-producing mechanism without an additional anterior procedure.

In two experiments we examined the effectiveness of ideokinetic imagery and flexibility combined with abdominal strength training as methods for improving the spinal angles of lordosis and kyphosis and reducing low back pain. Ideokinetic imagery is a postural development technique that involves using movement images to gain subcortical control over the spinal musculature. Experiment 1 investigated the effectiveness of these treatments for males with a previous history of low back pain. Findings indicated that only ideokinetic imagery had a positive effect on the spinal column and low back pain. Experiment 2 extended these findings by investigating males and females using a noninvasive video analysis technique to record changes in spinal angles. This study further supports the effectiveness of ideokinetic imagery as a postural development technique in males with acute spinal angles. In these subjects spinal angles improved significantly, and the subjects reported complete cessation of low back pain. This research supports the use of ideokinetic imagery as an inexpensive and noninvasive technique to improve poor posture and reduce low back pain.

We report the results of a preliminary test of a simple, easily learned procedure which facilitates improvement in body mechanics. It lessens the common tendency for hyperextension of the neck and for the use of the lower back as a major joint in sitting and standing. The resulting improvement in level of fixation of neck and pelvis should facilitate the body's defense against the force of gravity. The concept is supported here by the observed changes in physiological parameters which followed practice of the new procedure, which we call the Mitzvah Exercise.

The spinal injured child has speical needs owing to the processes of physical, mental and social growth. Goals of physical treatment programs include prevention of: genitourinary complications; contractures; pressure sores; long bone fractures, hip subluxation and dislocation; spinal deformity. Nonoperative treatment of spinal deformity employing external support should be initiated when the potential for spinal deformity exists. External support delays the development of spinal deformity, improves sitting balance and allows free upper extremity use. The overall treatment programs must consider altered body proportions, immaturity of strength and coordination. Case examples of children with spinal injury are presented above to illustrate specific problems stemming from immaturity of physical, cognitive, and social development. Spinal surgery can be a conservative measure in the growing child when there is radiologic evidence of progressive spinal deformity. Posterior spinal fusion with Harrington instrumentation and external support permits immediate return to vertical activity.

In 17 myelomeningocele patients with subluxating or dislocated hips, 31 posterolateral iliopsoas were treated by transfers, as described by Sharrard, in addition to complimentary procedures to balance muscle power and center the hip joint. Surgical goals are to stablize the hips within the acetabulum and prevent the occurrence of severe fixed flexion and adduction contractures of the hip and secondary lumbar lordosis. Surgery is performed at about 1 year of age with bilateral adductor transfer to the ischium, followed in 2 weeks by the posterolateral transfer of the iliopsoas muscle, first on one hip and 2 weeks later following with the other hip. Adductor transfer to the ischium reduces the adductor and secondary flexor power of the adductor longus and anterior fibers of the adductor brevis. After transfer it provides some extensor power. The range of abduction is increased. The transferred iliopsoas muscle has a better mechanical advantage in its new function as an abductor and extensor, and the hips were better centered radiographically than the cases with iliopsoas transfer alone. Fewer bony procedures were required to center the hips when the iliopsoas transfer was performed in children before the age of 1 1/2 years.

The literature documents progression of spondylolisthesis, most commonly during the adolescent growth spurt. Twenty-eight patients with Grades I and II spondylolisthesis were treated with antilordotic braces. Presenting signs and symptoms included back pain (61%), tight hamstrings (53%), increased lordosis (25%), and mild scoliosis (21%). Three patients presented with spondylolysis and progressed to a slip prior to initiation of brace treatment. Mean duration of brace treatment was 25 months. In the brace, lateral roentgenograms demonstrated a significant reduction of lumbar lordosis and sacral inclination. At the conclusion of brace treatment all patients were pain-free and none had demonstrated a significant increase in slip percent.