Retrospective study.
To assess the long-term relationship between sagittal alignment of the cervical spine and patient-reported health-related quality-of-life (HRQOL) scores after multilevel ...posterior cervical fusion, and to explore whether an analog of T1 slope minus C2-C7 lordosis ('T1S-CL') impacts on patients' clinical outcomes.
A 6-month follow-up study demonstrated that, similar to the thoracolumbar spine, the severity of disability increases with sagittal malalignment after cervical reconstruction surgery.
From 2007 to 2014, 31 consecutive patients having multilevel posterior cervical fusion for cervical stenosis, myelopathy, and deformities met inclusion criteria. To determine the true impact of the alignment on HRQOL, patients who have pseudarthrosis, a misplaced screw, junctional pathologies, or adjacent level disc herniation were excluded. Radiographic measurements included: C0-C2 lordosis, C2-C7 lordosis, C2-C7 sagittal vertical axis (SVA), T1 slope, and T1S-CL. Pearson correlation coefficients were calculated between pairs of radiographic measures and HRQOL.
C2-C7 SVA positively correlated with neck disability index (NDI) scores (r = 0.550). For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of 43.5 mm, beyond which correlations were most significant. The T1S-CL also correlated positively with C2-C7 SVA and NDI scores (r = 0.827 and r = 0.618, respectively). Results of the regression analysis indicated that a C2-C7 SVA value of 43.5 mm corresponded to a T1S-CL value of 22.2°.
This minimum 2-year follow-up study showed that disability of the neck increased with cervical sagittal malalignment after surgical reconstruction and a greater T1S-CL mismatch was associated with a greater degree of cervical malalignment. Specifically, a T1S-CL mismatch greater than 22.2° corresponded to severe disability (NDI>25) and positive cervical sagittal malalignment, defined as C2-C7 SVA greater than 43.5 mm.
4.
Biomechanical study.
To demonstrate that robotic cervical traction can apply closed cervical traction as effectively as manual weight-and-pulley traction in extension spring and cadaveric models.
...Closed cervical traction is used to reduce subaxial cervical spine dislocation injuries and to distract the intervertebral space during cervical spine surgery. Weight-and-pulley cervical traction relies on cumbersome and imprecise technology without any safeguard to prevent over-traction or weights being pulled/released inadvertently.
A prototype robotic traction device was designed and manufactured by the authors with real-time tensile force measurement, ±1-lbs (5 N) force application accuracy, locking/non-backdriveable linear actuators with actuator position sensing, 200-lbs (900 N) maximum force capability, up to 20° of flexion/extension manipulation, <25-lbs (111 N) device weight, and compatibility with Gardner-Wells tongs or Mayfield head clamp. The device was tested using an extension spring model and an intact fresh cadaver specimen to assess applied and desired force over time and radiographic changes in the cervical spine as traction force increased. The cadaver was tested in manual traction initially and then robotic traction in 10-lbs (50 N) increments up to 80-lbs (355 N) to compare methods.
The prototype device met or exceeded all requirements. In extension spring testing, the device reached the prescribed forces of both 25-lbs (111 N) and 80-lbs (355 N) accurately and maintained the desired weight. In cadaveric testing, radiographic outcomes were equivalent between the prototype and manual weight-and-pulley traction at 80-lbs (355 N; disk space measurements within ±10% for all levels), and the device reached the desired weight within±1-lbs (5 N) of accuracy at each weight interval.
This preliminary work demonstrates that motorized robotic cervical traction can safely and effectively apply controlled traction forces.
Sarcopenia, defined as decreased skeletal mass, is an independent marker of frailty that is not accounted for by other risk-stratification methods. Recent studies have demonstrated a clear ...association between paraspinal sarcopenia and worse patient-reported outcomes and complications after spine surgery. Currently, sarcopenia is characterized according to either a quantitative assessment of the paraspinal cross-sectional area or a qualitative analysis of paraspinal fatty infiltration on MRI. No studies have investigated whether the cervical paraspinal cross-sectional area correlates with fatty infiltration of the cervical paraspinal muscles on advanced imaging.
Do patients undergoing anterior cervical discectomy and fusion (ACDF) with increasing paraspinal fatty degeneration on advanced imaging also demonstrate decreased cervical paraspinal cross-sectional area?
Between 2011 and 2017, 98 patients were prospectively enrolled in a database of patients undergoing one- to three-level ACDF for degenerative conditions at a single institution. To be eligible for this prospective study, patients were required to undergo an MRI before surgery, be older than 18 years, and have no previous history of cervical spine surgery. Two independent reviewers, both surgeons not involved in the patients' care and who were blinded to the clinical outcomes, retrospectively assessed the paraspinal cross-sectional area and Goutallier classification of the right-sided paraspinal muscle complex. We then compared the patients' Goutallier grades with their paraspinal cross-sectional area measurements. We identified 98 patients for inclusion. Using the Fuchs modification of the Goutallier classification, we classified the fatty degeneration of 41 patients as normal (Goutallier Grades 0 to 1), that of 47 patients as moderate (Grade 2), and that of 10 patients as severe (Grades 3 to 4). We used ANOVA to compare all means between groups.
There was no difference in the mean paraspinal cross-sectional area of the obliquus capitus inferior (normal 295 ± 81 mm2; moderate 317 ± 104 mm2; severe 300 ± 79 mm2; p = 0.51), multifidus (normal 146 ± 59 mm2; moderate 170 ± 70 mm2; severe 192 ± 107 mm2; p = 0.11), or sternocleidomastoid (normal 483 ± 150 mm2; moderate 468 ± 149 mm2; severe 458 ± 183 mm2; p = 0.85) among patients with mild, moderate, and severe fatty infiltration based on Goutallier grading. There was a slightly greater longus colli cross-sectional area in the moderate and severe fatty infiltration groups (74 ± 22 mm2 and 66 ± 18 mm2, respectively) than in the normal group (63 ± 15 mm2; p = 0.03).
Because our study demonstrates minimal association between paraspinal cross-sectional area and fatty infiltration of the cervical paraspinals, we recommend that physicians use the proven qualitative assessment of paraspinal fatty infiltration during preoperative evaluation of patients who are candidates for ACDF. Future studies investigating the relationship between cervical paraspinal cross-sectional area and patient-reported outcomes after ACDF are necessary to lend greater strength to this recommendation.
Level III, diagnostic study.
Retrospective cohort.
The purpose of the study was to evaluate differences across surgical approaches (anterior, posterior, or combined anterior-posterior) in terms of outcomes following treatment ...for floating lateral mass (FLM) fractures. Furthermore, we sought to determine whether operative approach to FLM fracture treatment remains superior to nonoperative treatment in terms of clinical outcomes.
FLM fractures of the subaxial cervical spine involves separation of the lateral mass from the vertebrae via a disruption of both the lamina and pedicle, resulting in a disconnection of the superior and inferior articular processes. This subset of cervical spine fractures is highly unstable, making proper treatment selection of great importance.
In this single-center, retrospective study, we identified patients meeting the definition of an FLM fracture. Radiological imaging from the date of injury was reviewed to ensure presence this injury pattern. Treatment course was assessed to determine nonoperative versus operative treatment. Operative treatment was divided into patients who underwent anterior, posterior, or combined anterior-posterior spinal fusion. We then reviewed postoperative complications among each of the subgroups.
Forty-five patients were determined to have a FLM fracture over a 10-year span. The nonoperative group had n=25, and evidently, there were no patients that crossed over to surgery due to subluxation of the cervical spine after nonoperative treatment. The operative treatment group had n=20, and consisted of 6 anterior, 12 posterior, and 2 combined approaches. Complications appeared in posterior and combined groups. Two hardware failures were noted in the posterior group, along with two postoperative respiratory complications in the combined group. No complications were observed for the anterior group.
None of the nonoperative patients in this study required further operation or management of their injury, indicating nonoperative treatment as a potentially satisfactory management for appropriately selected FLM fractures.
Cervical spine deformity surgery has significantly evolved over recent decades. There has been substantial work performed, which has furthered the true understanding of alignment and advancements in ...surgical technique and instrumentation. Concomitantly, understanding of cervical spine pathology and the contributing drivers have also improved, which have influenced the development of classification systems for cervical spine deformity and the development of treatment-guiding algorithms. This article aims to provide a synopsis of the current knowledge surrounding cervical spine deformity to date, with particular focus on preoperative expected alignment targets, perioperative optimization, and the whole operative strategy.
Retrospective cross-sectional review of a large database.
Little is known regarding extension K-lines for treatment of cervical myelopathy. Therefore, this study seeks to examine differences between ...K-lines drawn in neutral and extension.
The modified K-line is a radiological tool used in surgical planning of the cervical spine. As posterior cervical decompression and fusion often results in patients being fused in a more lordotic position than the preoperative neutral radiograph, a K-line measured in the extension position may offer better utility for these patients.
Total of 97 patients were selected with T2-weighted, upright cervical magnetic resonance imaging taken in neutral and extension. For each patient, the K-line was drawn at the mid-sagittal position for both neutral and extension. The distance from the most posterior portion of each disk (between C2 and C7) to the K-line was measured in neutral and extension and the difference was calculated. Paired t test was used to assess significant differences.
Across all levels between C2 and C7 there was an increase in the distance between the dorsal aspect of the disk and K-line when comparing neutral and extension radiographs. The average change in difference (extension minus neutral) at each cervical spinal level was 0.9 mm (C2-C3), 2.5 mm (C3-C4), 2.6 mm (C4-C5), 2.0 mm (C5-C6), and 0.9 mm (C6-C7). A paired t test showed that the K-line increase from neutral to extension was statistically significant across all disk levels ( P <0.001).
When positioned in extension, patients experience a significant increase in distance from the dorsal aspect of a disk to the K-line compared to when positioned in neutral, especially between C3 and C6. This is clinically relevant for surgeons considering a posterior cervical decompression and fusion in patients with a negative modified K-line on preoperative magnetic resonance imaging, as these patients may have enough cervical cord drift back when fused in an extended position, maximizing likelihood of improving postoperative DSM functional outcomes.
To compare craniofacial and cervical morphology between skeletal Classes II and III applying Geometric Morphometric Methods (GMM). Twenty-six cervical and craniofacial landmarks of 40 Class II and 39 ...Class III individuals were digitalized on lateral cephalograms. Procrustes ANOVA, generalized Procrustes, principal component analyses, and thin-plate spline function were applied to assess the pattern of shape variation of craniofacial structure and the cervical spine in relation to skeletal classes. Compared with Class III, Class II individuals presented a maxillary protrusion, mandibular retrusion, shorter mandibular corpus, posterior mandibular ramus rotation, anterior cranial base rotation, and a smaller centroid size. Furthermore, a forward and smaller cervical spine were observed. With GMM, the shape and size differences between skeletal classes can be analyzed visually and numerically.
STUDY DESIGN.A prospective comparative study.
OBJECTIVE.This study aimed to establish cervical spine morphometry, alignment, and range of motion (ROM) and to clarify the impact of these age-related ...and degenerative changes.
SUMMARY OF BACKGROUND DATA.There are no studies that have evaluated differences in the results of cervical spine radiographs between a large series of cervical spondylotic myelopathy (CSM) patients and healthy subjects.
METHODS.We enrolled 1016 consecutive CSM patients who underwent laminoplasty. CSM patients were also divided based on each decade of life between the fourth and ninth decades. We also enrolled a total of 1230 healthy volunteers as asymptomatic subjects in this study. There were at least 100 men and 100 women in each decade of life between the third and eighth decades. Cervical sagittal alignment on neutral and flexion-extension views was measured by the Cobb method at C2–7. ROM was assessed by measuring the difference in alignment between flexion and extension.
RESULTS.Cervical lordosis in the neutral position increased gradually with age in both groups. CSM patients showed significantly smaller lordotic angles compared with those shown by asymptomatic subjects within each decade. The total ROM decreased with increasing age in both groups. The total ROM of females was larger than males. The ROM of CSM patients was significantly smaller than asymptomatic subjects. The flexion ROM did not change with aging in either group. There was no significant difference in the flexion ROM between males and females in the two groups. However, the extension ROM decreased gradually in both groups. The extension ROM of CSM patients was significantly smaller than asymptomatic subjects.
CONCLUSION.Age-related and degenerative changes in the cervical spine, alignment, and ROM in each decade of life were established between CSM patients and asymptomatic subjects.Level of Evidence1
