Intersegmental Kinematics of the Upper Cervical Spine: Normal Range of Motion and Its Alteration After Alar Ligament Transection

Functional Anatomy and Biomechanics of the Craniovertebral Junction

The craniovertebral junction (CVJ) involves the atlas, axis, and occiput along with the atlanto-occipital and atlantoaxial joints. The anatomy and neural and vascular anatomy of the junction render the CVJ unique. Specialists treating disorders that affect the CVJ must appreciate its intricate anatomy and should be well versed in its biomechanics. This first article in a three-article series provides an overview of the functional anatomy and biomechanics of the CVJ.

Association between Age, Sex and Cervical Spine Sagittal Plane Motion: A Descriptive and Correlational Study in Healthy Volunteers

Active motion examination of patients with cervical spine-related pathologies is necessary to establish baseline function, set physical therapy goals, and choose interventions. This study investigated the sagittal plane active range of motion (ROM) of the global (GCS) and upper cervical spine (UCS) in relation to age and sex in healthy volunteers. One hundred twenty-two volunteers aged 18 to 75 years participated. Volunteers were excluded if they displayed any characteristic that could affect cervical spine ROM. GCS and UCS flexion and extension were each measured three times using a CROM device. Linear regression models (LRMs) were developed to explore the relationships between age and sex and GCS and UCS ROM. The LRM for age showed a decrease in GCS flexion (-2.01°), GCS extension (-3.33°), and UCS extension (-1.87°) for every decade of increasing age. The LRM for sex showed that men displayed less ROM than women in GCS extension (-6.52°) and UCS extension (-2.43°). These results suggest an age-related loss of sagittal plane GCS ROM and UCS extension ROM, and sex-related differences in GCS and UCS extension with women having greater motion than men.

Association between age, sex and cervical and upper cervical rotation tests. Descriptive and correlational study in healthy volunteers

Background

Active cervical spine rotation (ACROM Rot) shows cervical rotation and flexion rotation test (FRT); side-bending rotation test (SBRT) and upper cervical axial rotation test (C0-C2ART) are described to measure upper cervical rotation. The objectives of this study are (1) to describe the normal range of motion (ROM) of ACROM Rot, and the ROM in FRT, SBRT and C0-C2ART tests; (2) to explore the correlation among the four tests and (3) to investigate the influence of age and sex in their ROM.

Methods

A cross-sectional study was carried out with healthy volunteers from 18 to 75 years of age. Tests were measured using a CROM device and a bubble inclinometer. Descriptive analysis was performed to establish normative data for the ROM tests. Correlation analysis was conducted to understand the relation between upper and global cervical rotation ROM and among the three upper cervical rotation tests. Linear regression models were developed to understand the influence of age and sex in the ROM of all tests.

Results

Normative values were obtained from 122 healthy volunteers (50% male), by sex and age strata. The degree of correlation ranged between 0.582 (p < 0.01) for FRT and ACROM Rot left and 0.217 (p < 0.05) for SBRT and C0-C2ART left. Linear regression models showed the influence of sex for ACROM Rot right (men -4.64° less than women), SBRT (men -4.1° less than women) left and C0-C2ART right and left (men -2.24° and -1.78° less than women). The age influenced rotation ROM with a decrease for every 10 years of -2.11° and -1.96° for ACROM Rot right and left, of -1.72° and -1.26° for FRT right and left and -0.58° and -0.41° for C0-C2ART right and left in the linear regression models. No association was found between age and SBRT (p = 0.63 for right SBRT and p = 0.49 for left SBRT).

Conclusion

Weak-to-moderate correlation was found between the upper cervical spine rotation tests and with the ACROM. Women had a larger ROM in ACROM Rot right, SBRT left and C0-C2ART. Decreases in ROM related with age were observed for ACROM Rot, FRT and C0-C2ART but not for SBRT.

Research on pharyngeal bacterial flora in transoral atlantoaxial operation and the postoperative follow-up study

Objectives

To study the changes of bacterial flora after a series of preoperative oral disinfection and the postoperative recovery of nerve function of patients with craniovertebral junction disorders who were treated with transoral approach operations.

Methods

This research analyzed 20 cases collected from October 2009 to May 2010. All these patients were with CVJ disorders, including 8 males and 12 females, aged 2 to 66 (38.1 on average), and they were all treated with transoral approach operations. The mucosa samples of the posterior pharyngeal wall were sent for bacteria culture. These samples were collected by sterile cotton swabs at four crucial points, including 3 days before operation/before gargling, 3 days after continuous gargling/after anesthesia intubation on the day of operation, after intraoperative cleaning and washing of the mouth, and after intraoperative iodophor immersion. The microflora was stained by means of smear and further counted after an investigation by microscope. The neural function of patients was evaluated by the ASIA classification and the JOA scores. All patients but two with posterior stabilization performed respectively underwent transoral atlantoaxial reduction plate (TARP) fixation consecutively in the same sitting. A regular reexamination of cervical vertebra with lateral and open mouth X-ray, CT and MRI was conducted after operation to evaluate the reduction of atlantoaxial dislocation, internal fixation position, bone graft fusion, inflammatory lesions and tumor recurrence.

Results

This bacteriological research showed that the mucosa of the posterior pharyngeal wall of all the patients was in a sterile state after a series of oral preoperative preparations and intraoperative iodophor disinfection, which was considered as type I incision. The bacterial culture results of the mucosa samples of the posterior pharyngeal wall collected at different time points showed significant differences (χ² = 42.762, P = 0.000). All the patients had improvement in ASIA, and their neural functions were improved to different levels after operation. There was a significant difference in JOA scores before and after operation (t = 8.677, P = 0.000). Postoperative imaging examination showed that the atlantoaxial screw position was good and firm, and the CVJ disorders were treated appropriately.

Conclusion

It is safe and effective to cut the posterior pharyngeal muscle layer and implant internal fixation by means of transoral approach.