An in Vivo, Three-Dimensional (3D), Functional Centers of Rotation of the Healthy Cervical Spine.

OBJECTIVE: This study examined cervical center of rotation (COR) positions in 7 postures using validated cone beam computed tomography (CBCT) combined with 3D-3D registration in healthy volunteers. METHODS: CBCT scans were performed on 20 healthy volunteers in 7 functional positions, constructing a three-dimensional (3D) model. Images were registered to the neutral position using 3D-3D registration, allowing analysis of kinematic differences and rotational axes. COR measurements were obtained for each segment (C2/3 to C6/7) in each posture. RESULTS: The CORs of C2/3 to C6/7 were predominantly posterior (-5.3 ± 3.8 ∼ -0.6 ± 1.2 mm) and superior (16.5 ± 6.0 ∼ 23.6 ± 3.2 mm) to the intervertebral disc's geometric center (GC) in flexion and extension. However, the C4/5 segment's COR was anterior to the GC (2.0 ± 9.8 mm) during flexion and close to it in the right-left direction. During left-right twisting, the CORs of C2/3-C6/7 were posterior (-21.8 ± 10.5 ∼-0.9 ± 0.8 mm) and superior (3.1 ± 7.5 ∼23.2 ± 3.6 mm) to the GCs in anterior-posterior and superior-inferior directions, without consistent right-left directionality. During left-right bending, each segment's COR was predominantly posterior (-25.2 ± 13.1 ∼-6.5 ± 9.9 mm) and superior (0.3 ± 12.5 ∼12.1 ± 5.1 mm) to the GC in anterior-posterior and superior-inferior directions, except for the C2/3 segment, located inferiorly (-5.9 ± 4.1 mm) in left bending. The right-left COR position varied across segments. CONCLUSIONS: Our findings reveal segment-specific and posture-dependent COR variations. Notably, the CORs of C3/4, C4/5, and C5/6 consistently align near the intervertebral disc's GC at different postures, supporting their suitability for total disc replacement surgery within the C3/4 to C5/6 segments.

Novel one-pot strategy for fabrication of a pH-Responsive bone-targeted drug self-frame delivery system for treatment of osteoporosis.

Osteoporosis (OP) is a systemic metabolic orthopedic disorder prevalent in elderly people, that is characterized by a decrease in bone mass. Although many therapeutics have been adopted for OP treatment, many of them are still not well satisfied clinical requirements and therefore development of novel therapeutics is of great significance. In this work, a novel bone-targeting drug self-frame delivery system (DSFDS) with high drug loading efficiency and pH responsive drug release was fabricated by condensation of curcumin (Cur), amino group terminated polyethylene glycol (NH2-PEG), and alendronate (ALN) using hexachlorocyclotriphosphonitrile (HCCP) as the linker. The final product named as HCCP-Cur-PEG-ALN (HCPA NPs) displayed excellent water dispersity with small size (181.9 â€‹± â€‹25.9 â€‹nm). Furthermore, the drug loading capacity of Cur can reach 25.8%, and Cur can be released from HCPA NPs under acidic environment. Owing to the introduction of ALN, HCPA NPs exhibited strong binding to HAp in vitro and excellent bone-targeting effect in vivo. Results from cellular and biochemical analyses revealed that HCPA NPs could effectively inhibit the formation and differentiation function of osteoclasts. More importantly, we also demonstrated that HCPA NPs could effectively reduce bone loss in OVX mice with low toxicity to major organs. The above results clearly demonstrated that HCPA NPs are promising for OP treatment. Given the simplicity and well designability of fabrication strategy, explicit therapy efficacy and low toxicity of HCPA NPs, we believe that this work should be of great interest for fabrication of various DSFDS to deal with many diseases.

Clinical efficacy and imaging analysis for the surgical treatment of thoracolumbar infections in elderly patients: a retrospective study.

Few reports have been conducted to comparing surgical results and safety evaluations between the different types of infections in geriatric patients with thoracolumbar infections. The aim of this study is to investigate the safety and efficacy of surgical treatment for thoracolumbar infections in elderly patients. 21 patients with pyogenic spondylodiscitis (PS) and 26 patients with tuberculous spondylodiscitis (TS) were enrolled in the study. All patients were treated using one-stage posterior debridement, decompression, and pedicle screw fixation. Comparison of operative safety parameters between the two groups. Clinical efficacy was evaluated using visual analogue scale (VAS) score, the American Spinal Injury Association (ASIA) grade, the short form (SF)-36 survey and Oswestry disability index (ODI) to determine patient quality of life pre- and post-operatively. Hospitalisation and intensive care unit duration in the PS group were significantly shorter than in the TS group (P < 0.05). The total incidence of post-operative complications for both groups was 44.7%. More complications occurred in the TS group, but the difference was not significant. The scores of VAS, ODI and SF-36 of all 47 patients were significantly improved compared with those before operation.The VAS and SF-36 scores (physical component) were significantly better in the PS group 6 months post-operatively, and the SF-36 (mental component) scores were significantly better in the PS group at the 1-year follow-up. Neurological status in both groups improved post-operatively, and 83% of patients reported satisfactory results based on the modified MacNab standard. Imaging results showed that bone graft fusion improved in both groups at 6 months, 1 year and at the final follow-up. One-stage posterior debridement, decompression, interbody fusion, and internal fixation can be considered a safe and effective method of treating spinal infections in the elderly. This method can improve nerve function, reconstruct spinal stability, and enhance the quality of life of elderly patients. Both PS and TS who underwent surgery achieve similar clinical and radiological results.

Transoropharyngeal closed reduction for traumatic atlantoaxial dislocation: a novel technique for fast and precise reduction.

PURPOSE: The aim of this study is to introduce a new technique for the rapid and accurate reduction of traumatic atlantoaxial dislocation (TAAD) and to investigate its radiological and clinical outcomes. METHODS: The clinical outcomes of 18 patients who were diagnosed with acute TAAD and underwent rapid transoropharyngeal closed reduction in our hospital were retrospectively analyzed from January 2015 to December 2020. Following general anaesthesia, all patients were immediately treated with oropharyngeal reduction under somatosensory evoked potential monitoring. The Japanese Orthopedic Association score, neck disability index and visual analog scale score for neck pain were used to evaluate clinical efficacy. Atlantodental distance, posterior atlantodental interval, and the clivus-canal angle were used to assess reduction and spinal cord compression. RESULTS: The mean follow-up time was 23.3 months, with a range of 13-38 months. No neurovascular injury occurred during the operations. For all patients, the closed reduction method through the oropharynx under general anaesthesia was successful, and the success rate of reduction was 100%. All patients recovered uneventfully with marked improvement in clinical outcomes and imaging parameters (P < 0.01). Two patients developed mild postoperative dysphagia. One patient developed postoperative fever and pulmonary infection. CONCLUSION: Rapid trans-oropharyngeal closed reduction can safely, effectively, and rapidly reduce acute TAAD. This method provides a new strategy for treatment of the condition.

In vivo 3-Dimensional Kinematics Study of the Healthy Cervical Spine Based on CBCT Combined with 3D-3D Registration Technology.

STUDY DESIGN: A cervical biomechanical study. OBJECTIVE: We sought to demonstrate the three-dimensional (3D) intervertebral motion characteristics of the cervical spine in healthy volunteers using cone beam computed tomography (CBCT) combined with 3D-3D registration technology. SUMMARY OF BACKGROUND DATA: No previous studies have used CBCT combined with 3D-3D registration technology to successfully documented in vivo 3D intervertebral six-degrees-of-freedom (6-DOF) motions of the cervical spine. METHODS: Twenty healthy subjects underwent cervical (C1-C7) CBCT scans in seven functional positions. Segmented 3D vertebral body models were established according to the cervical CBCT images. A 3D-to-3D registration was then performed for each vertebral body in the different positions to calculate the 3D segmental motion characteristics in vivo. RESULTS: During flexion-extension, the range-of-motion (ROM) of C1-C2 and C4-C5 was significantly greater than the other segments. The average coupled axial rotation and lateral bending of each segment were between 0.6° and 3.2°. The average coupling translations in all directions were between 0.2 and 2.1 mm. During axial rotation, the ROM of C1-C2 was 65.8 ±â€Š5.9°, which accounted for approximately 70% of all axial rotation. The motion and displacement of C1-C2 coupled lateral bending were 11.4 ±â€Š5.2° and 8.3 ±â€Š1.9 mm, respectively. During lateral bending, the ROM of C3-C4 was significantly greater than C1-C2, C5-C6, and C6-C7. The coupled axial rotation of C1-C2 was 34.4 ±â€Š8.1°, and the coupled lateral translation was 3.8 ±â€Š0.5 mm. The coupled superoinferior and anteroposterior translation of each cervical segment were between 0.1 and 0.6 mm. CONCLUSION: CBCT combined with 3D-3D registration was used to accurately measure and record the ROMs of lateral bending, axial rotation, and flexion-extension in cervical vertebrae under physiological-load conditions. Our findings may contribute to the diagnosis of cervical spinal disease, the development of new surgical techniques, and the restoration of normal, cervical segmental movement.Level of Evidence: 3.

Motion characteristics of the lower lumbar spine in individuals with different pelvic incidence: An in vivo biomechanical study.

BACKGROUND: Pelvic incidence is the quantification of the pelvis anatomical shape which has significant effect on the occurrence of various lumbar degenerative diseases. The aim of this study was to measure the in vivo dynamic motion characteristics of the lower lumbar spine in people with different pelvic incidence. METHODS: A total of 55 volunteers were included in the study. The participants were devided into 3 groups (A: pelvic incidence≤40°, B: 40° < pelvic incidence <60° and C: pelvic incidence ≥60°). The L3-S1 vertebrae of each subject was MRI scanned to construct 3D models. The lumbar spine was then imaged using a dual fluoroscopic imaging system as the subject performed physiological position. The 3D vertebral models and the fluoroscopic images were used to reproduce the in vivo vertebral positions along the motion path. The relative translations and rotations of each motion segment were analyzed. FINDINGS: At the L5-S1 segment, the primary ranges of motion for left-right axial rotation and flexion-extension of the patients with large pelvic incidence (3.28° ± 0.79°, 7.56° ± 1.81°) were significantly larger than normal pelvic incidence (2.61° ± 1.01°, 6.57° ± 2.18°) and small pelvic incidence (2.00° ± 0.60°, 5.83° ± 1.67°). INTERPRETATION: The anatomic variable pelvic incidence is associated with the ranges of motion in lower lumbar vertebrae, especially in the L4-5 and L5-S1 segments.

A Technique for the In Vivo Study of Three-dimensional Cervical Segmental Motion Characteristics After Anterior Screw Fixation for Odontoid Process Fractures.

STUDY DESIGN: Kinematics of the cervical spine was investigated using cone beam computed tomography (CBCT) images combined with three dimensions to three dimensions (3D-3D) registration technology in patients after anterior odontoid screw fixation (AOSF) surgery. OBJECTIVE: The aim of this study was to investigate in vivo 3D cervical motion characteristics of patients who had undergone AOSF surgeries. SUMMARY OF BACKGROUND DATA: AOSF surgery is a classic surgical method for the treatment of odontoid fracture, but there are few studies that investigated its effect on in vivo biomechanics of the cervical spine. Postoperative biomechanical characters of the atlantoaxial joint (C1-C2) and the caudal adjacent segment (C2-C3) have yet to be clarified. METHODS: The study involved 14 patients subjected to a procedure of AOSF with lag screw. Subjects were matched with 14 healthy controls. All subjects underwent CBCT scanning of the cervical spine under seven functional positions. A 3D-3D registration was performed for each vertebra at each functional position to calculate the segmental motion characteristics. The ranges of motion (ROMs) of the C1-C2, C2-C3, and the overall cervical spine (C1-C7) for each of the functional positions were determined. RESULTS: The ROMs of the AOSF group were significantly (P < 0.05) smaller than the control group in flexion-extension positions for the C1-C2 (7.0°vs.11.0°), C2-C3 (3.7°vs.6.7°) and C1-C7 (43.3°vs.54.4°). The twisting ROM of the C1-C2 was 39.3° in the AOSF group and 65.7° in the control (P < 0.05), the bending ROM of the C2-C3 was 2.8° in the AOSF group and 8.9° in the control (P < 0.05). The twisting ROM of C1-C7 segment was 63.2° for the AOSF and 98.1° for the healthy control groups (P < 0.05). CONCLUSION: Although AOSF surgery reduced the flexion-extension ROMs of all investigated spinal segments, additionally, it reduced twisting ROMs of C1-C2 and C1-C7, but only lateral bending ROM of C2-C3, when compared with the control group. The data implied that the AOSF surgery would result in different biomechanics changes in the atlantoaxial segment and caudal adjacent segment. Longer-term follow-up studies of larger patient cohorts are necessary to evaluate the clinical outcomes of patients after the AOSF surgery.Level of Evidence: 3.

[Effect of precursor on growth and accumulation of alkaloids of Lycoris radiata suspension cells].

In order to investigate the effects of phenylalanine, tyrosine and tyramine on the growth of Lycoris radiata suspension cells and the accumulation of alkaloids, the growth quantity of the cells as well as the content of alkaloids in cells were determined, which were treated with above three kinds of precursors alone and phenylalanine combined with tyrosine respectively. The results indicate that the addition of phenylalanine alone and addition of phenylalanine on the basis of tyrosine at high concentration (200 micromol/L) had no significant effect on the growth of Lycoris radiata suspension cells and the content of alkaloids in cells; whereas tyrosine and tyramine promoted the growth of the cells and alkaloids accumulation. Treated with tyrosine at high concentration (200 micromol/L), the content of alkaloids of the cells was 2.56-fold higher than that of the control group, the amounts of lycoramine (3.77 mg/g) and galanthamine (4.46 mg/g) were 6.61-fold and 6.97-fold higher than that of the control group, respectively. When treated with tyramine (200 micromol/L), the amount of alkaloids in Lycoris radiata suspension cells was 2.63-fold higher than that of the control group, and the amounts of lycoramine (4.45 mg/g) and galanthamine (5.14 mg/g) were 9.08-fold and 9.18-fold higher than that of the control group, respectively. The above results demonstrate that adding tyrosine and tyramine in the media significantly promoted the growth of the Lycoris radiata suspension cells and alkaloids accumulation in the cells.

[Determination of five endogenous hormones in wheat by high performance liquid chromatography].

A high performance liquid chromatographic (HPLC) method was developed to determine the five endogenous hormones including indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellic acid (GA3 ), zeatin (ZT) and salicylic acid (SA) in wheat. The separation conditions were optimized, and methanol was chosen as the extraction solvent. Then the extract was extracted by petroleum ether and ethyl acetate, and purified with the Sep-Pak C18 column. The chromatographic conditions were as follows: Eclipse XDB-C18 reversed phase column (250 mm x 4.6 mm, 5 microm), the flow rate of 1 mL/min, the injection volume of 10 microL, and the detection wavelength of 240 nm were used for the separation of SA from 14.5 min to 18 min, while the detection at 254 nm used for the separation of the others. Methanol (A) and acetic acid aqueous solution (pH 3.6) (B) were used as the mobile phases with the linear gradient set as follows: 0-7 min 20% A, 7-10 min 20% A-28% A, 10-17 min 28% A, 17-19 min 28% A-40% A, 19-35 min 40% A. The results showed that: the hormones were separated well with the recoveries of 96.9% - 98%, and the RSDs were in the range of 1.54% to 2.29%. It is a reliable method for rapid, accurate separation and determination of the endogenous hormones in wheat.