The effect of training on lumbar spine posture and intervertebral disc degeneration in active-duty Marines

Changes in intervertebral sagittal alignment of the cervical spine from supine to upright

Cervical sagittal alignment is a critical component of successful surgical outcomes. Unrecognized differences in intervertebral alignment between supine and upright positions may affect clinical outcomes; however, these differences have not been quantified. Sixty-four patients scheduled to undergo one or two-level cervical arthrodesis for symptomatic pathology from C4-C5 to C6-C7, and forty-seven controls were recruited. Upright sagittal alignment was obtained through biplane radiographic imaging and measured using a validated process with accuracy better than 1° in rotation. Supine alignment was obtained from computed tomography scans. Coordinate systems used to measure supine and upright alignment were identical. Distances between adjacent bony endplates were measured to calculate disc height in each position. For both patients and controls, the C1-C2, C2-C3, and C3-C4 motion segments were in more lordosis when upright as compared with supine (all p < 0.001). However, the C4-C5, C5-C6, and C6-C7 motion segments were in less lordosis when upright as compared with supine (all p ≤ 0.004). There was an interaction between group and position at the C1-C2 (p = 0.002) and C2-C3 (p = 0.001) motion segments, with the controls demonstrating a greater increase in lordosis at both motion segments when moving from supine to upright. The results indicate that cervical motion segment alignment changes between supine and upright positioning, those changes differ among motion segments, and cervical pathology affects the magnitude of these changes. Clinical Significance: Surgeons should be mindful of the differences in alignment between supine and upright imaging and the implications they may have on clinical outcomes.

The application of key feature extraction algorithm based on Gabor wavelet transformation in the diagnosis of lumbar intervertebral disc degenerative changes

OBJECTIVE

Based on the theoretical basis of Gabor wavelet transformation, the application effects of feature extraction algorithm in Magnetic Resonance Imaging (MRI) and the role of feature extraction algorithm in the diagnosis of lumbar vertebra degenerative diseases were explored.

METHOD

The structure of lumbar vertebra and degenerative changes were respectively introduced to clarify the onset mechanism and pathological changes of lumbar vertebra degenerative changes. Most importantly, the theoretical basis of Gabor wavelet transformation and the extraction effect of feature information in lumbar vertebra MRI images were introduced. The differentiation effects of feature information extraction algorithm on annulus fibrosus and nucleus pulposus were analyzed. In this study, the data of lumbar spine MRI was randomly selected from the Wenzhou Lumbar Spine Research Database as research objects. A total of 130 discs were successfully fitted, and 109 images were graded by a doctor after observation, which was compared with the results of the artificial diagnosis. Through the comparison with the results of observation and diagnosis by professional doctors, the accuracy of feature extraction algorithm based on Gabor wavelet transformation in the diagnosis of lumbar vertebra degenerative changes was analyzed.

RESULTS

1. Compared with the results of the manual diagnosis, the accuracy of the classification method was 88.3%. In addition, the specificity (SPE), accuracy (ACC), and sensitivity (SEN) of the classification method were respectively 89.5%, 92.4%, and 87.6%. 2. The mutual information method and the KLT algorithm were utilized for vertebral body tracking. The maximum mutual information method was more effective in the case of fewer image sequences; however, with the increase of image frames, the accumulation of errors would make the tracking effects of images get worse. Based on the KLT algorithm, the enhanced vertebral boundary information was selected; the soft tissues showed in the obtained images were smooth, the boundary information of vertebral body was enhanced, and the results were more accurate.

CONCLUSION

The feature extraction algorithm based on Gabor wavelet transformation could easily and quickly realize the localization of the lumbar intervertebral disc, and the accuracy of the results was ensured. In addition, from the aspect of vertebral body tracking, the tracking effects based on the KLT algorithm were better and faster than those based on the maximum mutual information method.

Prevalence of Musculoskeletal Injuries Sustained During Marine Corps Recruit Training

Musculoskeletal injuries cost the U.S. Marine Corps approximately $111 million and 356,000 lost duty days annually. Information identifying the most common types of injuries and events leading to their cause would help target mitigation efforts. The purpose of this effort was to conduct an archival data review of injuries and events leading to injury during recruit training. An archival dataset of Marine recruits from 2011 to 2016 was reviewed and included 43,004 observations from 28,829 unique individuals. Injuries were classified as mild, moderate, and severe and categorized into new overuse, preexisting overuse, and traumatic. Injury classification and categorization were stratified by event in which the injury occurred. The majority of injuries were due to overuse, and the most common types were sprains, strains, iliotibial band syndrome, and stress fractures, which constituted over 40% of all injuries. Conditioning hikes were the primary event leading to injury, with 31% of all injuries occurring during this training; running claimed 12%. Most injuries sustained during basic training comprised sprains and strains. Marines who remained uninjured during basic training outperformed those who reported at least one injury on fitness tests. These results point to enhanced conditioning as a potential entry point to target future intervention efforts.

Mesenchymal Stem Cells Induced by Microencapsulated Chondrocytes on Repairing of Intervertebral Disc Degeneration

OBJECTIVE

To evaluate the therapeutic effects of mesenchymal stem cells induced by microencapsulated chondrocytes on repairing of intervertebral disc degeneration.

METHODS

Rabbit chondrocytes and bone marrow-derived mesenchymal stem cells (MSC) were derived. Chondrocytes were microencapsulated by a microcapsule generator to produce microencapsulated chondrocytes (MEC). MSC were then co-cultured with MEC (MSC-MEC) and the properties and the therapeutic effects on repairing of intervertebral disc degeneration were studied. For the in vitro study, cell proliferation, type II collagen, and glycosaminoglycan (GAG) were studied. The MSC induced by chondrocytes in the Transwell system (MSC-MLC) and pure MSC were used as the control group. For the in vivo studied, MSC-MEC were implanted into the intervertebral disc degenerated (IDD) models, and the radiological images, biomechanical properties, collagen II, and histology of the discs were studied. The IDD, MSC, and MSC-MLC groups were used as the control group.

RESULTS

In the in vitro study, no significant differences were found among the three groups, indicating that the microcapsule co-culture system will not affect the proliferation of MSC. The type II collagen quantity secreted by MSC-MEC was 23.57 ± 2.46 ng/μL, which was more than for MSC-MLC (15.14 ± 2.31 ng/μL) and MSC groups (4.17 ± 1.23 ng/μL, all P < 0.025). GAG secreted by MSC-MEC was 0.184 ± 0.006 mg/well, which was more than for the MSC-MLC (0.151 ± 0.011 mg/well) and MSC groups (0.023 ± 0.002 mg/well, all P < 0.025). In the in vivo study, no obvious degenerative or protrusive disc was found in the MSC-MEC group, while protrusive discs could be found in the MSC-MLC group, and both degenerative and protrusive discs were found in MSC and IDD groups, which indicated that the reparative effects of MSC-MEC on degenerated discs were better than for the control groups. Biomechanical properties of discs in the MSC-MEC group were maintained at all four time points (2nd, 4th, 8th, and 16th week after implantation). The compressive strength (CS) and the elastic modulus (EM) of MSC and IDD groups were consistently decreased. The CS of the MSC-MLC group was increased in the 4th week but decreased again in the 8th week, while the EM of the MSC-MLC group consistently decreased. Western blot results indicated that discs of the MSC-MEC group had more collagen II, which is an important component of discs. Histology staining showed that the nucleus pulposus of MSC-MEC was complete; no obvious fragment of component loss was found, while those of MSC-MLC, MSC, and IDD groups were widened, broken, and hollow.

CONCLUSION

The microencapsulation method for half-contact co-culturing improves the differentiation extent of MSC, and MSC induced by chondrocytes could also be used for treatment of IDD.

Lumbar Muscle Structure Predicts Operational Postures in Active-Duty Marines

Background The relationship between lumbar spine posture and muscle structure is not well understood. Objectives To investigate the predictive capacity of muscle structure on lumbar spine posture in active-duty Marines. Methods Forty-three Marines were scanned in this cross-sectional study, using an upright magnetic resonance imaging scanner while standing without load and standing, sitting, and prone on elbows with body armor. Cobb, horizontal, and sacral angles were measured. Marines were then scanned while unloaded in supine using a supine magnetic resonance imaging scanner. The imaging protocol consisted of T2 intervertebral disc mapping; high-resolution, anatomical, fat-water separation, and diffusion tensor imaging to quantify disc hydration and muscle volume, fat fraction, and restricted diffusion profiles in the lumbar muscles. A stepwise multiple linear regression model was used to identify physiological measures predictive of lumbar spine posture. Results The multiple regression model demonstrated that fractional anisotropy of the erector spinae was a significant predictor of lumbar posture for 7 of 18 dependent variables measured, and explained 20% to 35% of the variance in each model. Decreased fractional anisotropy of the erector spinae predicted decreased lordosis, lumbosacral extension, and anterior pelvic tilt. Conclusion Fractional anisotropy is inversely related with muscle fiber size, which is associated with the isometric force-generating capacity of a muscle fiber. This suggests that stronger erector spinae muscles predict decreased lordosis, lumbosacral extension, and anterior pelvic tilt in a highly trained population. J Orthop Sports Phys Ther 2018;48(8):613-621. Epub 17 May 2018. doi:10.2519/jospt.2018.7865.