Normal Cervical Spine Research Articles

Quantifying the ranges of relative motions of the intervertebral discs and facet joints in the normal cervical spine

Functional neck motion is achieved by the cervical segments with each composed of an intervertebral disc (IVD) and two facet joints (FJs). Using biplane fluoroscopic imaging, we investigated the ranges of motion (ROMs) of the three joints in the cervical spines (from C3 to C7) of eighteen asymptomatic subjects. Three functional neck motions were examined, including flexion–extension (FE), lateral bending (LB) and axial twisting (AT). Our measurements showed that the translations of both IVD and FJs primarily occurred in the sagittal plane during all neck motions, and the anteroposterior translations of IVDs were significantly smaller than those of the corresponding FJs (p < 0.05) at all segments. For example, the ranges of IVD and FJ anteroposterior translations at C3/4 were 2.7 ± 0.7 mm vs. 3.5 ± 1.1 mm in FE, 0.9 ± 0.5 mm vs. 4.6 ± 1.1 mm in LB, and 1.0 ± 0.5 mm vs. 3.1 ± 1.0 mm in AT. Furthermore, we introduced an IVD-FJ translation ratio, which represents the ratio of the IVD to FJ translational ROMs. In FE neck motion, the IVD-FJ anteroposterior translation ratios decreased from 0.81 ± 0.18 at C3 to 0.52 ± 0.19 at C3, indicating gradually increasing resistances of IVDs compared to FJs from the proximal to distal levels. In LB neck motion, the smallest IVD-FJ translation ratios (0.14 ± 0.09 and 0.43 ± 0.30) occurred at C4/5 for both anteroposterior and left–right translations. In AT neck motion, the largest IVD-FJ anteroposterior translation ratio (0.42 ± 0.21) occurred at C3/4, and was significantly different from those at C4/5 and C5/6 (p < 0.05). These data could be used as references for improving motion-preserving cervical treatment methods that aimed to achieve the normal ranges of translational motions of both IVD and FJs.

The 3 Sagittal Morphotypes That Define the Normal Cervical Spine: A Systematic Review of the Literature and an Analysis of Asymptomatic Volunteers.

Cervical alignment is vital for maintaining horizontal gaze and sagittal balance. The aims of this study were to summarize previously published descriptions of normative cervical alignment and to analyze a cohort of asymptomatic volunteers in order to identify natural clusters of normal radiographic parameters. We performed a systematic review of the literature on radiographic measurements of asymptomatic volunteers through a search of MEDLINE and ScienceDirect databases. We then performed an analysis of demographic and radiographic parameters of volunteers without back or neck complaints. Only subjects with a chin-brow vertical angle (CBVA) within previously published normal limits were retained for analysis. A 2-step cluster analysis was used to find natural groups of cervical alignment. Differences among groups were investigated with a post hoc analysis of variance (ANOVA). We included 37 articles in our analysis. There was a broad spectrum of both C2-C7 lordosis-kyphosis and T1 slope across ages and sexes. Of the 119 asymptomatic volunteers who were available for analysis, 84 (with a mean age [and standard deviation] of 49.0 ± 17.1 years) had a CBVA ranging from -4.7° to 17.7°. The cluster analysis identified 3 alignment groups based on cervical lordosis-kyphosis and T1 slope (silhouette measure of cohesion, >0.6). Twenty-seven volunteers (32.1%) were identified as the "kyphotic curve cohort" (KCC) (mean C2-C7 Cobb angle, -8.6° ± 7.3°; mean T1 slope, 17.4° ± 6.6°), 43 volunteers (51.2%) were identified as the "medium lordosis cohort" (MLC) (mean C2-C7 Cobb angle, 8.7° ± 7.2°; mean T1 slope, 26.6° ± 4.0°), and 14 volunteers (16.7%) were identified as the "large lordosis cohort" (LLC) (mean C2-C7 Cobb angle, 21.2° ± 7.2°, mean T1 slope, 39.5° ± 6.4°) (p < 0.001 for both). Moving from KCC to LLC, there was a significant decrease in C0-C2 lordosis (p = 0.016). Examination of the cervical vertebral orientation demonstrated that C4 had a constant orientation relative to the horizontal (p = 0.665). Correlation analysis between C2-C7 and vertebral orientations again demonstrated that C4 orientation was independent of C2-C7 alignment. We have identified 3 morphotypes of the cervical spine based on C2-C7 alignment and T1 slope. These findings demonstrate the broad definition of normal cervical alignment and the range of cervical lordosis-kyphosis that is acceptable.

Computed Tomography Evaluation of Craniovertebral Junction in Asymptomatic Central Rural Indian Population.

Objectives Craniovertebral junction (CVJ) is a unique, mobile and complicated component of our spine which necessitates specific study pertaining to its structure as well as pathologies. This study aims to report the normative data detailing the CVJ anatomy among the rural population of Central India which would help us in understanding the joint dynamics. Materials and Methods A retrospective observational study was undertaken in the Department of Neurosurgery and Radiology, Mahatma Gandhi Institute of Medical Sciences, Sewagram, Maharashtra, from December 2018 to May 2019. A total of 255 head injury patients with a normal CT brain cervical spine were included in this study. Anterior and posterior atlantodental interval (AADI/PADI), clivus length (CL), foramen magnum diameter (FMD), Boogard’s and basal angle (BOO & BA) were measured and analyzed. Statistical Analysis Statistical analysis was done using Microsoft Excel 2016. A web-based, open source application known as OpenEpi.com (version 3.01) was used for applying unpaired t -test. Results This study had a mean age of 42.9 years. The difference in mean value of AADI between male and female population was not found to be statistically significant, while in case of PADI, CL, FMD, BOO and BA, it was found to be significant ( p < 0.05). On comparison of cases with age ≤ 20 years and > 20 years, we found the difference in values of ADI, CL and FMD to be statistically significant ( p < 0.05). Conclusion Although there are some similarities, namely, AADI measurements as compared with other studies, there are differences in cutoff values of other parameters. Being a major draining reference center for rural population in India, this data can be extrapolated to a similar population for reference.

Computerized Tomography-Based Morphometric Analysis of Cervical Spinal Canal in Central Indian Population

Objective Normal cervical spine canal morphometry is critical for understanding the pathology of certain diseases and for proper preoperative planning. Computerized tomography (CT) scan can replace older conventional radiography techniques by providing more accurate morphometric measurements. This study was aimed to find out various dimensions of the cervical spinal canal of central Indian population. Materials and Methods A prospective study was conducted including 100 consecutive cervical spine CT scan of asymptomatic adult subjects. The anteroposterior sagittal canal diameter (SCD), transverse canal diameter (TCD), canal surface area (CSA), and Pavlov-Torg Ratio (PTR) from C2 to C7 were calculated. Statistical Analysis Data were entered in Microsoft Excel Sheet 2007 and statistical analysis was performed by IBM SPSS statistics 2.0 version. p -Value < 0.05 was considered as significant. Results Age ranged from 18 years to 77 years with mean age 39.5 years. There was no significant difference in all the dimensions (SCD, TCD, CSA) in male and female except at C2 level, where SCD, TCD, and CSA were significant larger in male. The mean SCD, TCD, and CSA is largest at C2 level (14.4 ± 1.63 mm, 21.57 ± 1.59 mm, and 156.20 ± 24.98 mm 2 , respectively) and smallest at C4 level (12.77 ± 1.48 mm, 20.37 ± 1.72 mm, and 130.42 ± 21.20 mm 2 ). PTR showed very little variation. Conclusion Normal values of cervical spinal canal could serve as a future reference. CT scan provides more accurate measurement. More studies are needed as there could be variations in dimensions in different regions in India.

A Report on Prenatal Diagnosis of a Rare Case of Fetal Acrania and Omphalocele by Doppler Examination

A congenital anomaly, fetal acrania (exencephaly) is, in which the fetal brain is not surrounded completely or partially by the skull bones. It is suggested that there is lacking of mesenchymal migration in the fourth week of embryological age. The first-trimester diagnosis must be made with restraint because the fetal cranium is not fully calcified before 10-11 weeks; therefore, if only midsagittal views of the fetus are obtained, misdiagnosis may occur. Another anomaly, omphalocele, a ventral defect of the umbilical ring resulting in herniation of the abdominal viscera, is one of the most common congenital abdominal wall defects seen in the newborn. Omphalocele is associated with trisomy [18]. The defect occurs in 1 in 6000 to 1 in 10,000 live births. The anencephaly sequence begins with acrania, which affecting the central nervous system with an incidence of ~1:1000 pregnancies. In our case a female 28 years old visited our ultrasound clinic for anomaly scan. The gestational age was 18 weeks 4 days. On ultrasound examination the presentation of fetus was cephalic and longitudinal lie. The sonographic scan revealed fully developed fetal brain having no calvarium. The brain was covered by a thin membranous structure. Compression of fetal brain by transducer was observed due to absence of cranium. The scan revealed the brain floating in the amniotic fluid over the base of skull. Facial structures were normal. Normal and well-coordinated movements were noted in in the fetal body parts. There was symmetry in Fetal nose and naso-labial folds and were well appreciated. It was also noted that spinal canal showed normal morphology with normal Cervical, thoracic and lumbar spines. The fetal abdomen showed a central mass protruding out from anterior abdominal wall. The mass is covered by a membrane and contains small intestines and liver. There was direct insertion of the umbilical cord into the midline of omphalocele. After taking consent form from the patient and her family, an elective prostaglandin abortion was performed. After delivery placenta was completely removed. Brain was covered by a membrane. There was a mass protruding through anterior abdominal wall and multiple abdominal viscera’s were protruding out through the midline gap in the anterior abdominal wall. This breach was centrally located equivalent to umbilicus connection. About 1-2mm thick was covering the protruding organs.

Corrective exercises specific for adolescent idiopathic scoliosis presented with bilateral leg pain: a case report describing an adaptive program and the recorded improvement as expressed by Cobb angle

Adolescent idiopathic scoliosis is considered as the most common type of scoliosis. A 13-year-old female complained of bilateral leg pain, left &gt; right, and severe headache. She was referred to an orthopaedic physical therapy clinic. Spinal X-ray revealed right thoracolumbar scoliosis with Cobb angle of about 48°. The primary curve was in the lumbar vertebrae, directed to the left, and the secondary curve was in the thoracic vertebrae, directed to the right. Two surgeons recommended corrective surgery, while one recommended physiotherapy for 6 months. The third surgical opinion was based on magnetic resonance imaging that presented normal cervical spine, mild scoliotic deformity of lower dorsal vertebrae with right-sided convexity and of lumbar vertebrae with left-sided convexity, L4–5 broad based posterior and left posterolateral disc protrusion, and L5–S1 mild central posterior disc protrusion. At the final evaluation after 18 months of a corrective exercise program, the patient reported no symptoms at rest or with exercises. The improvement was evidenced by Cobb angle change from 48° to 21°, pelvic shift, and general spinal flexibility and strength. The current case report describes a specific corrective exercise protocol adapted to a case of adolescent idiopathic scoliosis that presented with bilateral leg pain.

Finite element method to study cervical postoperative stability

A cervical spine model built by means of the finite element method was used to determine the risk of postoperative cervical instability in relation to the type of discectomy, in cervical disc herniation. Furthermore, this model was employed to check whether, at the adjacent levels of the fusion discectomy, the intervertebral translation during cervical movements will maintain the normal amplitude [normal ROM] or its amplitude will decrease.&#x0D; The intervertebral displacement and the tension arising from motion and weight in the cervical vertebral structure were thus determined through computer modelling using the above-mentioned method and the software Abaqus. It resulted in a cervical spine model consisting of 739666 finite elements interacting through 210530 nodes, with biomechanical properties following the vertebral anatomical structures modelled.&#x0D; Two movement situations were studied to determine the behaviour of this model. Firstly, the moment of force for flexion and extension of 1 Nm. Secondly, we aimed to establish the maximum flexion and extension for a normal cervical spine model in order to determine the momentum value of moving forces for each of them.&#x0D; It was showed that both anterior cervical microdiscectomy without fusion and cervical discectomy with cage fusion (used for the surgical treatment of cervical disc herniation at one level), ensure postoperative vertebral stability when performed properly. Both types of surgery reduce the mobility of the cervical spine, although more in the case of fusion discectomy. The intradiscal tension increases in movement in both models, with a higher intensification in the fusion discectomy model.&#x0D; The practical conclusion is that microdiscectomy without fusion is preferable in the case of a single-level cervical disc herniation occurred to a cervical spine without instability.

Effects of intervertebral disc degeneration on segmental rotation and intradisc pressure of c4-c6 cervical spine using finite element analysis

The spinal segment C4-C6 of the cervical region is one of the most frequent site for injuries in spinal cord. Cervical degenerative disc disease develops due to loss of hydration in the intervertebral discs with increasing age. The spinal segment progresses to develop painful conditions due to high flexion and rotation movements in the upper extremity bones. The main aim of the study to analyse the effects of intervertebral disc degeneration on biomechanics of the cervical spine. The three dimensional computed tomography image was used and the finite element models of the cervical spine were developed with various levels of intervertebral disc degeneration at the C4-C6 functional spinal unit. The developed model is validated with the published data. The biomechanical effects of mild and moderate disc degeneration on the mechanical behaviour of cervical spine were studied using the developed Finite element models. The annulus fibrosis and nucleus pulposus material properties were varied to achieve moderate degeneration. The validated model is modified to various conditions with different mechanical properties and the effects intradisc pressure and progressive degeneration on the range of motion and on intradisc pressure. The analysis and the comparison is made between mild, moderate with normal human cervical spine in terms of progressive intervertebral disc degeneration. Based on this study the range of motion decreased with degeneration and the intra disc pressure increased with progressive degeneration.

Intradural extramedullary tumor in the stenotic cervical spine resected through open-door laminoplasty with hydroxyapatite spacers: report of two cases

BackgroundSafe excision of spinal cord tumors depends on sufficient visualization of the tumor and surrounding structures. In patients with spinal cord tumor adjacent to a stenotic spinal canal, extensive bony decompression proximal and distal to the tumor should be considered for safer excision of the tumor. Extensive wide laminectomy is one choice for such cases, but postoperative problems such as kyphotic deformity remain a concern.Case presentationA 76-year-old man and a 60-year-old woman presented with symptomatic intradural extramedullary spinal cord tumors in the cervical spine. Both patients showed a combination of spondylotic changes in the cervical spine and stenotic condition at the level of the tumor. Both tumors were successfully resected through open-door laminoplasty with hydroxyapatite (HA) spacers, with the tumor located on the side of the laminoplasty. Histological diagnosis was schwannoma for both tumors. HA spacers completely bonded to the host bone and did not interfere with postoperative magnetic resonance imaging (MRI) of the inside of the spinal canal. Cervical spine alignment was maintained at the final follow-up of 6 years in both cases.ConclusionLaminoplasty with HA spacers enabled successful tumor extirpation, reliable MRI follow-up after surgery, and maintenance of normal cervical spine alignment. Laminoplasty with HA spacers represents a good option for the treatment of cervical spinal cord tumor in patients combined with spinal stenosis.

COMPUTER 3D-MODELING OF PATIENT-SPECIFIC NAVIGATIONAL TEMPLATE FOR CERVICAL SCREW INSERTION

Objective. To prove the effectiveness of 3D computer modeling and printing of patient-specific templates for cervical spine screw fixation. Materials and Methods . Based on the MSCT data of three patients, 3D models of cervical vertebrae and guiding templates were produced. The screws were inserted transpedicularly into 3D-printed models of C 2 –C 7 vertebrae and C 1 lateral masses using standard cervical instrumentation. This technology was then clinically tested in a patient with C 2 tumor, in whom posterior stabilization of C 1 –C 3 vertebrae was performed using guiding templates. In the postoperative period, MSCT was performed to monitor the position of screws. Results. When implanting screws into 3D-models, technical difficulties were not revealed. After insertion of screws, a visual assessment of the 3D vertebra model was made. Malpositions in models were not detected. Based on the proven technique, a clinical approbation was performed in a patient with normal cervical spine pattern. MSCT study revealed the deviation of screws relative to the planned trajectory by no more than 2 mm, with no malpositions. Conclusion. The first domestic description of the technique of navigation using guiding templates is presented. Of all the existing methods, this is the most reliable way of screw positioning in the cervical spine. The possible insertion error does not affect the quality of positioning.

Cervical spine taper ratios: Normal tolerance limits.

Background Spinal canal tapering, which can be measured as taper ratios, affects cerebrospinal fluid flow dynamics. We calculated the tolerance interval for normal cervical spine taper ratios to facilitate the detection of abnormal taper ratios. Methods We collected a series of patients who had cervical spine magnetic resonance studies reported as normal. We measured anteroposterior diameters of the cervical spine and calculated C1-C4, C4-C7, and C1-C7 taper by standard methodology. We calculated the normal tolerance limits for taper ratios and compared results of this study with data in previous reports on taper ratios. Results We enrolled 78 patients aged 2-55 years. The 99% tolerance limits for the taper ratios for C1-C4, C4-C7, and C1-C7 were -0.31 to +0.09, -0.11 to +0.14, and -0.13 to +0.05 cm/level, respectively. Age and sex were not significant variables for taper ratios. Taper ratios in this study agreed with those reported for controls in previous studies. Patients with syringomyelia in previous reports tended to have taper ratios outside the normal tolerance limits. Conclusion Normal limits of the cervical taper ratios are reported.

Cervical Facet Orientation Varies with Age in Children: An MRI Study.

Within the spine, mobility and stability are principles that drive anatomic morphology. Based on radiographic measurements, the orientation of cervical facet joints has been proven to change throughout child growth. However, because of the mainly cartilaginous composition of the vertebrae in the young child, the lack of osseous landmarks makes radiograph-based measurements unreliable. The aims of our study were to evaluate the change in the sagittal orientation of the cervical facet joints with age based on magnetic resonance imaging (MRI) of asymptomatic children and to compare it to the changes in vertebral body dimensions. Sagittal images passing through the center of the facet joint or through the center of the vertebral body were used to assess facet orientation at every cervical level. Anteroposterior facet orientation was defined as the angle between the superior facet and a line perpendicular to the posterior wall of the vertebral body. Vertical was defined as parallel to the posterior wall; horizontal was defined as perpendicular to the posterior wall. Vertebral body height and anteroposterior diameter were measured as well. MRI data of the normal cervical spine of 90 children who were 2 months to 18 years of age, obtained for neurologic evaluation, were used for this study. For each level from C3 to C7, there was a positive correlation between facet orientation and age (R = 0.498, p < 0.001). The facet joints were the most vertical at C3 (43.9°) and C7 (49.6°), whereas C5 had the most horizontal facets (39.4°). The greatest rate of change in facet orientation was observed between 6 and 9 years of age. Our results demonstrate that facets become more vertical as a function of age. However, other parameters than age must be considered to explain the variation of facet orientation. At C3 and C7, the facet orientation was more vertical, which may increase stability. In between, C5 facets were shallower, which may increase mobility and flexion-extension range of motion.

Surgical Treatment of Lower Cervical Fracture-Dislocation with Spinal Cord Injuries by Anterior Approach: 5- to 15-Year Follow-Up

Lower cervical fracture-dislocations frequently occur with spinal cord injuries. There is no clear consensus on best treatment option. Anterior approach surgery with direct decompression and reduction has become widely accepted. We assessed clinical outcomes of anterior approach surgery in a retrospective cohort study. From January 2001 to January 2011, 312 patients with lower cervical spine fracture-dislocation with spinal cord injuries who were treated by the anterior approach were retrospectively analyzed. Of 312 patients, 218 (70%; 121 men and 97 women) met inclusion criteria. Clinical efficacy was evaluated using Odom's criteria and statistical analysis based on Cobb angle of kyphosis and Neck Disability Index and Japanese Orthopedic Association scores. Neurofunctional recovery of patients was assessed by the American Spinal Injury Association system. Average follow-up was 8.9 ± 2.9 years (range, 5-15 years). Kyphosis angle and Neck Disability Index and Japanese Orthopaedic Association scores were significantly changed from preoperative values of 10.6° ± 8.9° and 39.7 ± 4.3 and 7.6 ± 2.4 to last follow-up values of-5.2° ± 8.6° and 10.8 ± 4.6 and 15.6 ± 1.2 (P < 0.05). Of patients, 197 (90.4%) had good to excellent outcomes, 14 (6.4%) had satisfactory outcomes, and 7 (3.2%) had poor outcomes. Varying degrees of neurologic function recovery were shown by 143 of the original 218 patients (65.6%) and 140 of 191 patients with incomplete paralysis (73.3%). For lower cervical fracture-dislocation with spinal cord injuries, satisfactory clinical outcomes can be obtained with an anterior approach. The anterior approach restored normal cervical spine structure and promoted functional recovery to achieve a good long-term curative effect.

Do universal critical spine dimensions exist

The effective spinal canal diameter is the fundamental index which will determine whether a patient of any compressive cervical spine pathology will get neurological deficit or not. So we analysed this index in our subset of population. 180 subjects with normal or near normal cervical spine magnetic resonance imaging were included. Antero-posterior diameter and transverse diameter of spinal canal from C3 to C7 was measured. Similarly spinal cord antero-posterior and transverse diameters were measured. Space available for cord was calculated at each of these levels in both sexes as the difference between the antero-posterior diameter of the spinal canal and that of the spinal cord. The mean value with standard deviation of cervical spinal canal diameter antero-posterior diameter at C3, C4, C5, C6 and C7 was 13.69±1.248, 13.34±1.186, 13.15±1.233, 13.12±1.275 and 13.73±1.226 mm respectively. The spinal cord antero-posterior diameter at the same level was 7.61±0.728, 7.58±0.677, 7.40±0.653, 7.12±0.657 and 6.69±0.622 mm respectively. The mean cervical spinal canal diameter of the local population in our region is different from the rest of the country. This has two implications; first the ancestral lineage is matching with some remote races of the world for which a detailed study may be needed. Secondly the dimension at which we call critical stenosis may be different in the region as compared with the rest of the country.

Anatomical Consideration for Posterior Atlantoaxial Transarticular Screw Fixation from Reformatted Two-Dimensional CT Images

Background: Posterior transarticular C1-C2 fixation by screw is a widely used technique to correct atlantoaxial instability. However, the screw trajectory must be precise because the adjacent vital organs include the spinal cord and vertebral artery in the transverse foramen. Due to the lack of an objective measuring method, clarifying the range of the safe zone of screw trajectory in both the sagittal and coronal planes is important. Objective: To clarify the safe zone and ideal trajectory for screw fixation ensuring safety and without violating the transverse foramen and spinal canal. Methods: Radiographs of the normal upper cervical spine and coronal reconstruction CT scans from the entry point of the screw on C2 was performed and the safe zone for the screw path was drawn. The points of screw intersection on the superior articular surface of C2 were measured from the posterior rim of the superior articular surface of C2 then the safe zone of the screw in the coronal plane was drawn in the coronal oblique plane along the screw direction. Results: Average safe zone in the sagittal plane was 51.6 – 61.2 relative to the superior articular of C2 and the safe zone in the coronal view was medially 9.5 and laterally 4.2 relative to the midline of the spinous process. The safe zone and ideal screw trajectory should intersect C2 at 8.03 and 4.5 mm from the posterior rim of the superior articular surface on C2. Conclusion: The result of this study showed the range of the safe zone of the posterior atlantoaxial screw trajectory that guides to minimize the risk of misdirection and violating the transverse foramen by the screw. The areas on the superior articular of C2 intersected by the trajectories making the longest paths are guides to purchase the longest path of bone to achieve more stability and pullout strength

Cervical spine motion during tracheal intubation with King Vision™ video laryngoscopy and conventional laryngoscopy: a crossover randomized study.

The King Vision™ (KVL) videolaryngoscope with a wide field of view could potentially reduce cervical spine motion during intubation. We aimed to compare the extent of cervical spine movement during laryngoscopy using the KVL and Macintosh laryngoscopes. Following ethical approval, 29 patients with a normal cervical spine requiring general anesthesia and tracheal intubation were randomly subjected to both KVL and Macintosh laryngoscopy in a crossover. Cervical spine motion during each laryngoscopy was radiologically examined by measuring changes in cumulative spine motion and changes from the neutral position in the C0-C5 angles formed by the adjacent vertebrae. Time to tracheal intubation, laryngoscopic view, and ease of intubation were also recorded. Compared with direct laryngoscopy, the KVL resulted in significantly less movement of the C-spine at the C0-C1, and C3-C4, C4-C5 segments (mean differences: C0-C1: 3.01 ° [95% CI: -4.74° to -1.28°]; C3-C4: 1.81° [95% CI: -3.19° to -0.43°]; C4-C5: -0.88° [95% CI: -1.61° to -0.19°], P<0.02) and cumulative C-spine movement (mean 36.1˚[95% CI 32.72 to 39.51] vs. 44.1˚[95%CI: 39.54 to 48.75]; P=0.001). There was significant movement in the C0-C3 segment from baseline using both devices. Tracheal intubation took longer with KVL (mean difference: 12.7 s [95% CI: 9.15 to 16.13 s]; P=0.001) even though laryngeal visualization was improved (Cormack Lehane Grade I was reported in 100% KVL vs. 65.5% Macintosh laryngoscopies; P=0.001). In patients with normal cervical spine, KVL resulted in less extension of the cervical spine than direct laryngoscopy.

Normal cervical spine range of motion using digital inclinometer in male asymptomatic subjects of Aseer, Saudi Arabia

Background: Various studies determined the normal cervical spine range of motion (ROM) of a large group of patients with diverse socioeconomic and ethnic background and varying degree of routine daily activities. The purpose of this investigation was to quantify normal cervical ROM in male asymptomatic subjects of Aseer Region, Saudi Arabia. Methodology: Two hundred and thirty-three asymptomatic subjects with age group of 10-80 years participated in the study. Digital goniometer was used to measure the ROM of the cervical spine. This tool was employed in a clinical setting to evaluate the full active ROM (AROM) of the cervical spine (i.e., flexion/extension, lateral bending, and axial rotation). All the subjects were divided into seven groups in terms of age (10-19, 20-29, 30-39, 40-49, 50-59, 60-69, and 70-80 years) and the cervical ROM was determined. Six cervical movements (i.e., flexion/extension, lateral bending, and axial rotation) of five groups were analyzed and each of the six cervical AROMs decreased significantly with age. Results: All the cervical ranges decreased as the age increased. The maximum cervical range was recorded in cervical rotation left (71.81 ± 8.75°), followed by rotation right (70.58 ± 5.83°), extension (68.42 ± 10.30°), flexion (66.96 ± 8.62°), left side bending (54.62 ± 7.13°), and right side bending (52.69 ± 7.32°). Conclusion: Normal database of normal cervical ROM from age group of 10-80 years was established in male asymptomatic population of Aseer Region, Saudi Arabia.

Anatomic Study of Anterior Transdiscal Axial Screw Fixation for Subaxial Cervical Spine Injuries.

Anterior transdiscal axial screw (ATAS) fixation is an alternative or supplement to the plate and screw constructs for the upper cervical spine injury. However, no existing literatures clarified the anatomic feasibility of this technique for subaxial cervical spine. Therefore, the objective of this study was to evaluate the anatomical feasibility and to establish guidelines for the use of the ATAS fixation for the subaxial cervical spine injury.Fifty normal cervical spines had radiographs to determine the proposed screw trajectory (the screw length and insertion angle) and the interbody graft-related parameters (the disc height and depth, and the distance between anterior vertebral margin and the screw) for all levels of the subaxial cervical spine. Following screw insertion in 8 preserved human cadaver specimens, surgical simulation and dissection verified the feasibility and safety of the ATAS fixation.Radiographic measurements showed the mean axial screw length and cephalic incline angle of all levels were 41.2 mm and 25.2°, respectively. The suitable depth of the interbody graft was >11.7 mm (the distance between anterior vertebral margin and the screw), but <17.1 mm (disc depth). Except the axial screw length, increase in all the measurements was seen with level up to C5–C6 segment. Simulated procedure in the preserved specimens demonstrated that ATAS fixation could be successfully performed at C2–C3, C3–C4, C4–C5, and C5–C6 levels, but impossible at C6–C7 due to the obstacle of the sternum. All screws were placed accurately. None of the screws penetrated into the spinal canal and caused fractures determined by dissecting the specimens.The anterior transdiscal axial screw fixation, as an alternative or supplementary instrumentation for subaxial cervical spine injuries, is feasible and safe with meticulous surgical planning.

A new cervical artificial disc prosthesis based on physiological curvature of end plate: a finite element analysis

Study DesignThe study aimed to build a new cervical artificial disc C3–C7 segment prosthesis, and perform a biomechanical comparison between the new prosthesis and the Prestige LP prosthesis using a three-dimensional non-linear finite element (FE) model. PurposeThe study compared the biomechanical differences between the new cervical artificial disc prosthesis based on the physiological curvature of the end plate and the Prestige LP prosthesis after artificial disc replacement. Background ContextThere has been no prior research on artificial disc prostheses based on the physiological curvature of the end plate; studies of biomechanical changes after cervical disc arthroplasty (CDR) are few. MethodsAn FE model of the C3–C7 segments was developed and validated. A new cervical artificial disc prosthesis based on the physiological curvature of the end plate and the Prestige LP prosthesis were integrated at the C5–C6 segment into the validated FE model. All models were subjected to a follower load of 73.6 N and a 1 Nm in flexion-extension, lateral bending, and axial torsion. The segmental range of motion (ROM) and stress on the prostheses were analyzed. ResultsThe ROM in most segments after CDR with new cervical artificial disc prosthesis was more similar to that of the normal cervical spine than the Prestige LP prosthesis. However, there was no significant difference between the two prostheses. The stress on the new artificial disc was significantly less than that in the Prestige LP prosthesis. ConclusionsThere was no significant difference in ROM in all segments after CDR for the two prostheses. The stress on the new cervical artificial disc prosthesis based on the physiological curvature of the end plate was significantly less than that in the Prestige LP prosthesis. The new artificial disc prosthesis is feasible and effective, and can reduce the implant-bone interface stress on the end plate, which may be one of the causes of prosthesis subsidence.

Prevalence and pattern of cervical rib, transversomegaly and other vertebral anomalies in normal adult cervical spine in Kumaon region of Uttarakhand, India

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; A supernumary rib from seventh cervical vertebra is called cervical rib and is a common anomaly. Its true prevalence is not validated as most of these are asymptomatic thus do not get diagnosed. Its incidence has been reported in several geographic regions and ethnic clusters. Most of the studies rely on radiological data collected from evaluation of chest or neck radiographs of defined numbers.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A similar study to ascertain its presence and incidence, apart from sexual and morphological pattern is required for Kumaon region of Uttarakhand, India. The present study reports data extracted from study of 1500 radiographs and evaluating them for presence of cervical rib and other abnormalities. Demographic and other relevant details were noted.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Most of the cases were female and almost all cases of cervical rib or transversomegaly were bilateral. 0.8% and 1.4% cases were noted for cervical rib and transversomegaly respectively. Apart from it, 4 cases of vertebrae fusion and one case of hemi-vertebra leading to cervical scoliosis was also noted.&lt;/p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The prevalence of cervical rib was comparable to other studies considering the sample size. The calculation of true incidence however will require multi-discipline collaboration and robust data. This study, however, is important for further work in this regard and adds value to existing literature.