Shape analysis of the cervical spinous process

Variation in the morphology of spinous processes in the cervical spine - An objective and parametric assessment based on CT study

BACKGROUND

Typically, cervical vertebrae display bifid spinous processes. Nevertheless, this feature may vary both between subjects and even within the vertebrae of the same individual. Although such variation can be important in archaeological research, anthropological studies and forensic medicine, it has not so far been the subject of any detailed studies.

MATERIAL AND METHODS

An analysis of 200 cervical spine CT examinations was performed. The morphology of the spinous process was evaluated, and new anthropometric parameters were selected to allow a more precise quantitative analysis of the degree of bifidity.

RESULTS

The spinous process base (i.e. the part of the spinous process which was not bifid) was significantly longer in CII and CVII than in the other vertebrae. The spinous process branches (bifid elements) were significantly longer in CVI and CVII than in the other vertebrae. The angle between the branches was significantly sharper in CII and CVII than in CIII-CVI, on the right side, and CIII-CV, on the left side. On the right side, the branching coefficient (degree of branch development) was significantly higher for CII and significantly lower for CVI-CVII than for the other vertebrae. On the left side, the coefficient was significantly higher for CII and CIV, and significantly lower for CVI-CVII, compared to the other vertebrae.

CONCLUSION

Our findings highlight new objective parameters of morphological variability in the spinous processes of the cervical spine. They can form the basis of a new detailed differentiation of vertebrae and can represent an independent determinant of anatomical variability in the cervical spine.

Internal Morphology of the Odontoid Process: Anatomic and Imaging Study with Application to C2 Fractures

OBJECTIVE

Fracture of the odontoid process is a critical injury to diagnose and often treat. The aim of this anatomic study was to present a comprehensive understanding of this part of the C2 vertebra.

METHODS

We used 20 C2 vertebrae. Samples underwent imaging (computed tomography [CT] with and without three-dimensional reconstruction, micro-CT, 1.5T magnetic resonance imaging) and sagittal and coronal sectioning using a bone saw. Sectioned specimens were imaged under a digital handheld microscope, and transillumination of the bone was used to highlight its internal trabecular pattern. Three samples underwent infusion of the odontoid process with a hardening substance and were then decalcified.

RESULTS

Internal trabecular patterns of the odontoid process of all specimens were discernible. In sagittal and coronal sections, trabecular patterns were highlighted with transillumination, but the patterns were much clearer using the digital microscope. Magnetic resonance imaging and CT provided the least detail of the imaging methods, but the trabecular patterns could be identified. Three-dimensional reconstruction of CT data was the preferred imaging method over magnetic resonance imaging and CT without three-dimensional reconstruction. The most distinct trabecular and cortical patterns were seen using micro-CT. Osteoporosis was seen in 2 specimens (10%). Five specimens (25%) were found to have a subdental synchondrosis. For most specimens, the trabeculae were found throughout the odontoid process.

CONCLUSIONS

Improved knowledge of the anatomy, structural composition, and variations within the C2 vertebra may allow for better treatment options and patient care.

Inter-spinous process distance: a novel parameter predicting segmental lordosis during posterior cervical spine deformity surgery

PURPOSE

To investigate the normative value of distance between the spinous processes (inter-spinous process distance, ISPD), correlations between patients' demographics and ISPD, and determine cutoff ISPD values that result in segmental lordosis in posterior cervical-thoracic arthrodesis with instrumentation.

METHODS

We reviewed patients with visible lower cervical and cervicothoracic spinous processes (C5-T2) on dynamic X-rays. Radiographic measurements included segmental Cobb angles (S-Cobb) and ISPD, defined as the distance between midpoints of the spinous processes. Correlations between patient demographics and ISPD were evaluated. In addition, the cutoff ISPD values that predict segmental lordosis (S-Cobb < 0°) were determined using the receiver operating characteristics (ROC) curve and linear regression model.

RESULTS

We evaluated a total of 153 films on 51 patients. The mean ISPDs in neutral position were 16.0, 20.7, 23.2, and 26.0 mm at C5/6, C6/7, C7/T1, and T1/T2, respectively There were no or only weak correlations between ISPD and age, race, height, body weight, and BMI. We observed significant difference between male and female ISPDs at C7/T1 and T1/T2 (P < 0.05). The ISPDs had moderate/strong correlations with S-Cobb at each segment (- 0.450 ≤ r ≤ - 0.705). Based on the ROC curves, the following cutoff values of ISPD provided 100% positive predictive value for segmental lordosis: < 10 mm at C5-6; < 15 mm at each level from C6 to T2.

CONCLUSION

ISPD is a simple and useful parameter that correlates with the segmental Cobb angle. During posterior cervical deformity surgery, surgeons can intraoperatively predict adequate segmental lordosis by utilizing the vertebral level specific cutoff values of ISPD. These slides can be retrieved under Electronic Supplementary Material.

An anatomical study of the spinous process of the seventh cervical vertebrae based on the three-dimensional computed tomography reconstruction

Palpation of the seventh cervical vertebra (C7) is important for the diagnosis and treatment of neck and chest conditions. However, the spinous process of C7 (C7-SP) displays an anatomical deviation among individuals. The present study aimed to clarify anatomic characteristics of C7-SP by using a three-dimensional (3D) computed tomographic (CT) reconstruction technique. A total of 245 subjects meeting the selection criteria were examined. After CT scanning, the images were reconstructed in 3D. All subjects were grouped according to their deviation of C7-SP: Deviating to the right (DR group), deviating to the left (DL group) and no deviation (ND group). Three distances and three angles were recorded on C7-SP. The vertical distances between the borders of the left and right transverse processes and the tip of the SP, were termed DLTS and DRTS, respectively. The length of the SP was also determined. The angle of the SP deviation was referred to as ∠α, the angle between the SP axis and the line crossing the tips of the transverse processes was referred to as ∠β and the angle between the vertebral body axis and the SP axis was referred to as ∠γ. Among the three groups, differences in ∠α and ∠β were statistically significant (P<0.05). Furthermore, the DLTS was significantly different between the DL and ND groups (P<0.05). In addition, a significant difference in the DRTS was identified between the DR and ND groups (P<0.05). 3D CT reconstruction was reliable for studying anatomic characteristics of C7-SP. Based on this, patients may be preliminarily grouped according to the deviation of their C7-SP and the measurement of the C7-SP may guide clinical diagnoses and treatments.