OBJECTIVE: To explore the anatomical parameters of the cervical uncinate process "inflection point" through cervical CT angiography (CTA) and MRI measurements, offering a reliable and safe anatomical landmark for anterior cervical decompression surgery. METHODS: A retrospective analysis was conducted on the cervical CTA and MRI imaging data of normal adults who met the selection criteria between January 2020 and January 2024. The CTA dataset included 326 cases, with 200 males and 126 females, aged 22-55 years (mean, 46.7 years). The MRI dataset included 300 cases, with 200 males and 100 females, aged 18-55 years (mean, 43.7 years). Based on the CTA data, three-dimensional models of C ₃-C ₇ were constructed, and the following measurements were obtained from the superior view: uncinate process "inflection point" to vertebral artery distance (UIVD), uncinate process tip to vertebral artery distance (UTVD), uncinate process "inflection point" to "inflection point" distance (UID), uncinate process long-axis to sagittal angle (ULSA), and uncinate process "inflection point" to transverse foramen-sagittal angle (UITSA). From the anterior view, the anterior uncinate process to sagittal angle (AUSA) was measured. From the posterior view, the posterior uncinate process to sagittal angle (PUSA) was measured. Based on the MRI data, uncinate process "inflection point" to dural sac distance (UIDD) and dural sac width (DSW) were measured. The trends in measurement parameters of C ₃-C ₇ were observed, and the differences in measurement parameters between genders and between the left and right sides of the same segment were compared, as well as the difference in UID and DSW within the same segment was compared. RESULTS: The measurement parameters from C ₃ to C ₇ in the CTA data showed a general increasing trend, with no significant difference between the left and right sides within the same segment ( P>0.05). The UIVD, UTVD, and UID were greater in males than in females, with significant differences observed in the UIVD and UTVD at C ₃ and C ₆ and UID at C ₃, C ₆, and C ₇ ( P<0.05). The MRI measured DSW showed a general increasing trend from C ₃ to C ₇, and the DSW at C ₆ was greater in females than in males, with a significant difference ( P<0.05). The UIDD showed a gradual decreasing trend, with the smallest value at C ₆. There was no significant difference between males and females or between the left and right sides within the same segment ( P>0.05). The UID was greater than the DSW at C ₃-C ₇, and the differences were significant ( P<0.05). CONCLUSION The uncinate process "inflection point" is a constant anatomical structure located at the anteromedial aspect of the uncinate process tip and laterally to the dural sac. It maintains a certain safe distance from the vertebral artery. As a decompression landmark in anterior cervical spine surgery, it not only ensures surgical safety but also guarantees complete decompression.
Humans ; Adult ; Male ; Female ; Middle Aged ; Retrospective Studies ; Cervical Vertebrae/surgery* ; Magnetic Resonance Imaging ; Decompression, Surgical/methods* ; Young Adult ; Adolescent ; Computed Tomography Angiography ; Imaging, Three-Dimensional ; Vertebral Artery/anatomy & histology* ; Anatomic Landmarks/diagnostic imaging*

OBJECTIVE: To investigate correlation between preoperative C ₂ slope (C2S) and effectiveness at 2 years after short-segment anterior cervical discectomy and fusion (ACDF), with the aim of providing reliable indicators for predicting effectiveness. METHODS: One hundred and eighteen patients with cervical spondylotic myelopathy, who received short-segment ACDF between January 2018 and December 2022 and met the selection criteria, were enrolled in the study. There were 46 males and 72 females, aged from 26 to 80 years, with a mean age of 53.6 years. The operative duration was (127.6±33.46) minutes and the intraoperative blood loss was (34.75±30.40) mL. All patients were followed up 2 years. The pre- and post-operative Neck Disability Index (NDI), Japanese Orthopaedic Association (JOA) score, and visual analogue scale (VAS) score for pain were recorded. Based on the anteroposterior and lateral cervical X-ray films, the sagittal parameters of the cervical spine were measured [C ₂-C ₇ Cobb angle, C ₀-C ₂ Cobb angle, T ₁ slope, C2S, sagittal segmental angle (SSA) of the surgical segment, and average surgical disc height (ASDH) of the surgical segment]. Statistical analyses were performed to assess the differences in these indicators between pre- and post-operation, as well as the correlations between the preoperative C2S and the JOA score, NDI, and VAS score at 2 years after operation. The patients were allocated into group A (C2S >11.73°) and group B (C2S≤ 11.73°) according to the median value of the preoperative C2S (11.73°). The JOA score, NDI, and VAS score before operation and at 2 years after operation, as well as the differences between pre- and post-operative values (change values), were compared between the two groups. RESULTS: The T ₁ slope, C ₂-C ₇ Cobb angle, C ₀-C ₂ Cobb angle, SSA, and ASDH at immediate after operation and JOA score, NDI, and VAS score at 2 years after operation significantly improved in 118 patients when compared with preoperative ones ( P<0.05). Pearson correlation analysis showed that preoperative C2S was not correlated with JOA score and NDI at 2 years after operation ( P>0.05), but negatively correlated with VAS score ( P<0.05). There were 59 patients with preoperative C2S>11.73° (group A) and 59 with C2S≤11.73° (group B). There was no significant difference in preoperative JOA score, NDI, and VAS score between the two groups ( P>0.05). There were significant differences in VAS score at 2 year after operation and the change value between the two groups ( P<0.05); there was no significant difference in the JOA score and NDI ( P>0.05). CONCLUSION Patients with cervical spondylotic myelopathy and a higher preoperative C2S exhibited superior long-term pain relief and effectiveness following short-segment ACDF.
Humans ; Male ; Spinal Fusion/methods* ; Female ; Middle Aged ; Cervical Vertebrae/diagnostic imaging* ; Diskectomy/methods* ; Aged ; Adult ; Treatment Outcome ; Aged, 80 and over ; Spondylosis/diagnostic imaging* ; Pain Measurement ; Preoperative Period ; Follow-Up Studies

OBJECTIVE: To investigate the technical key points and effectiveness of ultrasonic bone scalpel-assisted anterior controllable antedisplacement and fusion (ACAF) for treating cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: Between June 2022 and December 2024, 11 OPLL patients underwent ultrasonic bone scalpel-assisted ACAF. The cohort included 8 males and 3 females, aged 49-74 years (mean, 56.7 years). The OPLL classification included 5 cases of mixed-type, 4 cases of segmental-type, and 2 cases of continuous-type cases. Ossification involved 2-5 spinal segments (mean, 3.2). Disease duration ranged from 2 to 18 months (mean, 6.2 months). The operation time, intraoperative blood loss, and complications were recorded. Pain improvement was assessed using the visual analogue scale (VAS) score, and neurological function was evaluated using Japanese Orthopaedic Association (JOA) score. Postoperative cervical CT and MRI were performed to measure spinal canal encroachment rate, spinal canal area, and spinal cord sagittal diameter. RESULTS: All operations were successfully completed. The operation time ranged from 174 to 360 minutes (mean, 255.9 minutes). The intraoperative blood loss ranged from 170 to 530 mL (mean, 345.9 mL). The C ₅ nerve root palsy occurred in 1 patient. No cerebrospinal fluid leakage, aggravated spinal cord injury, or recurrent/superior laryngeal nerve injuries occurred. All patients were followed 3-12 months (mean, 7.2 months). At last follow-up, VAS scores significantly decreased and JOA scores significantly increased compared to preoperative values ( P<0.05). According to the JOA improvement rate, the effectiveness was rated as excellent in 2 cases, good in 8, and fair in 1, with an excellent and good rate of 90.9%. Radiological re-examination revealed no implant loosening, screw breakage, or aggravated spinal stenosis. Postoperative spinal canal encroachment rate significantly decreased, while spinal canal area and spinal cord sagittal diameter significantly increased compared to preoperative measurements ( P<0.05). CONCLUSION For the treatment of cervical OPLL via ACAF, the intraoperative application of ultrasonic bone scalpel-assisted osteotomy enables precise vertebral groove creation and mobilization of the vertebra-ossification complex, thereby enhancing surgical safety and achieving satisfactory short-term effectiveness.
Humans ; Middle Aged ; Male ; Female ; Ossification of Posterior Longitudinal Ligament/diagnostic imaging* ; Aged ; Cervical Vertebrae/diagnostic imaging* ; Spinal Fusion/instrumentation* ; Treatment Outcome ; Ultrasonic Surgical Procedures/instrumentation* ; Operative Time

OBJECTIVE: To investigate the possible mechanism and fracture stability of subtypes of type B Hangman's fracture by using imaging observation. METHODS: Patients with type B Hangman's fractures admitted to multiple centers between January 2008 and October 2023 were selected as the research objects. The clinical data and imaging data of patients who met the selection criteria were extracted. The patients' age, gender, cause of fracture, disease duration, visual analogue scale (VAS) score of neck pain, neck disability index (NDI), and American Spinal Injury Association (ASIA) classification of spinal cord function were collected. Based on the imaging data, the anatomical structure of the contralateral superior articular process fracture, the relationship between the superior articular process fracture line and the position of the odontoid process, the associated posterior vertebral wall fracture and its classification, the incidence of vertebral arch floating and C _{2, 3} instability were observed. The superior articular fracture angle (SAFA), superior articular fracture displacement distance (SAFD), and C ₂ vertebral body rotation (VBRA) were measured. According to the anatomical structure of the contralateral superior articular process fracture, the patients were divided into a pedicle fracture group (POA group), a inferior articular process fracture group (IAP group), and a laminar fracture group (CSL group). The baseline data and imaging indexes were analyzed between groups, and the imaging anatomical characteristics of each subtype of fracture were observed to explore its possible mechanism and fracture stability. RESULTS: A total of 86 cases of type B Hangman's fractures were collected. There were 67 males and 19 females. The mean age was 51.0 years (range, 21-78 years). There were 48 cases of pedicle fracture (POA group), 25 cases of inferior articular process fracture (IAP group), and 13 cases of laminar fracture (CSL group). There was no significant difference in age, gender, cause of fracture, disease duration, VAS score of neck pain, and NDI between groups ( P>0.05). However, the incidence of spinal cord injury in POA group was the highest ( P<0.05). The incidences of superior articular process fracture line posterior to the odontoid process and posterior vertebral wall fracture in POA group were the highest ( P<0.05). The incidences of vertebral arch floating and C _{2, 3} instability in IAP group were the highest ( P<0.05). There were significant differences in SAFA and VBRA between groups ( P<0.05). There was no significant difference in SAFD between groups ( P>0.05). The differences in the incidences of fracture displacement>3 mm and VBRA>5° between groups were significant ( P<0.05). There were 78 cases of unstable Hangman's fracture, including 2 cases of simple C _2、3 instability, 22 cases of simple axis rotation and displacement instability, 8 cases of simple vertebral arch floating instability, and the rest of the patients had two or more types of instability. CONCLUSION The mechanism of different subtypes of type B Hangman's fracture may be that the lateral mass of the rotation of the atlas applied the overextension compression force to the unilateral superior articular process of the axis vertebra, and the contralateral pedicle, inferior articular process and lamina fractures were caused by direct violence or/and rotational violence to different degrees. The decomposition of this type of fracture into C _{2, 3} intervertebral, axis vertebra body displacement and rotation and vertebral arch floating instability is beneficial to the treatment and surgical approach selection.
Humans ; Spinal Fractures/surgery* ; Male ; Female ; Cervical Vertebrae/diagnostic imaging* ; Middle Aged ; Adult ; Tomography, X-Ray Computed ; Aged ; Odontoid Process/injuries* ; Fracture Fixation, Internal/methods* ; Young Adult

OBJECTIVE: To evaluate the effectiveness of the single-stage anterior eccentric kyphotic distraction reduction technique (EKD-RT) for treating lower cervical dislocation with locked facet joints, assessing its reduction success rate, neurological improvement, and safety. METHODS: A retrospective analysis was conducted on 67 patients with lower cervical dislocation and locked facet joints (21 unilateral, 46 bilateral) treated between January 2015 and January 2024. There were 39 males and 28 females, with an average age of 49.5 years (range, 22-75 years). The injured segments included C _{3, 4} in 4 cases, C _{4, 5} in 13 cases, C _{5, 6} in 22 cases, and C _{6, 7} in 28 cases. The interval between injury and admission ranged from 2 hours to 2 days (mean, 5.6 hours). Preoperative Frankel grading included grade A in 9 cases, grade B in 28 cases, grade C in 17 cases, grade D in 11 cases, and grade E in 2 cases. Japanese Orthopaedic Association (JOA) score was 7.0±1.4. All patients underwent single-stage anterior cervical discectomy and fusion. Following discectomy at the dislocated level, the EKD-RT was applied to unlock and reduce the locked facet joints, followed by internal fixation. Operation time, blood loss, reduction success rate, and complications were recorded. Interbody fusion status was evaluated using Bridwell criteria. Neurological status was assessed pre- and post-operatively using Frankel grading. Spinal cord function was scored using the 17-point JOA score, and the improvement rate was calculated. RESULTS: Successful reduction of the locked facet joints achieved in all cases. The operation time was 41-85 minutes (range, 63.3 minutes), and intraoperative blood loss was 50-360 mL (range, 125.0 mL). Complications included cerebrospinal fluid leakage in 2 cases; no severe complications such as major vascular injury or recurrent laryngeal nerve injury occurred. All patients were followed up 12-24 months (mean, 17.9 months). At last follow-up, radiological examination confirmed interbody fusion in all patients, with no implant failure or migration. The Frankel grading included grade A in 3 cases, grade B in 9 cases, grade C in 13 cases, grade D in 16 cases, and grade E in 26 cases; the JOA score reached 13.7±2.3; all of which significantly improved compared to preoperative levels ( P<0.05). The improvement rate of JOA score was 66.1%±24.7%. CONCLUSION The EKD-RT is an effective surgical approach for lower cervical dislocation with locked facet joints. It enables safe and efficient reduction of the locked facet joints via a single incision, resulting in significant neurological improvement with a low complication rate.
Humans ; Male ; Middle Aged ; Female ; Cervical Vertebrae/diagnostic imaging* ; Retrospective Studies ; Adult ; Aged ; Zygapophyseal Joint/injuries* ; Joint Dislocations/diagnostic imaging* ; Treatment Outcome ; Spinal Fusion/methods* ; Young Adult ; Kyphosis/surgery*

OBJECTIVE: Objective To investigate the relationship between cervical disc herniation and C₀-C₂ Cobb angle. METHODS: The clinical data of 301 patients with cervical disc herniation from 2020 to 2024 were retrospectively analyzed. The median value of C₀-C₂ Cobb angle measurements from 301 patients was used as the boundary, cervical disc herniation patients were divided into two groups, C₀-C₂ Cobb angle <28.50 group and 151 patients with C₀-C₂ Cobb angle≥28.50 group. Among them, 150 patients in C₀-C₂ Cobb angle <28.50 group included 53 males and 97 females, aged 23 to 76 (57.32±12.55) years, with a disease duration of 7 to 19 (13.81±5.32) months;the othor 151 patients with C₀-C₂ Cobb angle≥28.50 group including 61 males and 90 females, aged 25 to 74 (56.86±12.51) years, with a disease duration of 8 to 18 (14.13±5.56) months. The cervical lordosis angle (C₀-C₂ Cobb angle and C₂-C₇ Cobb angle), T₁ inclination slope (T₁S) and cervical sagittal axial distance (C₂-C₇ SVA) were measured on the lateral cervical radiographs. The correlation between C₀-C₂ Cobb angle and cervical disc herniation range, protrusion position, average protrusion size and other parameters was analyzed. RESULTS: When the C₀-C₂ Cobb angle<28.50°, the average protrusion size was (2.21±0.56) mm, the C₂-C₇ Cobb angle was (19.92±12.06)° and the C₂-C₇ SVA was (1.10±1.20) mm. When the C₀-C₂ Cobb angle≥28.50°, the average protrusion size was (2.38±0.60) mm, the C₂-C₇ Cobb angle was (12.01±13.09 )°, the C₂-C₇ SVA was (1.53±1.36) mm, and the difference was statistically significant (P<0.05). Between the two groups of patients with C₀-C₂ Cobb angle < 28.50° and C₀-C₂ Cobb angle≥28.50°, there were significant differences in the size of C_3,4, C_4,5, C_5,6, C_6,7, C₇, T₁ disc herniation in single segment (P<0.05 ). C₀-C₂ Cobb angle was correlated with age(r=-0.135, P<0.05 ), C₂-C₇ Cobb angle (r=-0.382, P<0.01 ), C₂-C₇ SVA (r=0.293, P<0.01), average protrusion size (r=0.139, P<0.05), and the size of C_3,4 (r=0.215, P<0.01 ), C_4,5 (r=0.176, P<0.01 ), C_5,6 (r=0.144, P<0.05 ), C_6,7 (r=0.158, P<0.05 ), C₇T₁ (r=0.535, P<0.05) disc herniation. CONCLUSION There is a positive correlation between C₀-C₂ Cobb angle and the size of cervical disc herniation. C₀-C₂ Cobb angle can reflect the degree of cervical disc herniation. Previous studies have shown that the biomechanical changes between C₀-C₂ Cobb angle, C₂-C₇ Cobb angle, C₂-C₇ SVA and cervical extensor muscle group may be risk factors for accelerating cervical disc herniation and this may be one of the mechanisms that C₀-C₂ Cobb angle is positively correlated with the size of cervical disc herniation.
Humans ; Male ; Female ; Middle Aged ; Intervertebral Disc Displacement/physiopathology* ; Adult ; Cervical Vertebrae/diagnostic imaging* ; Aged ; Retrospective Studies ; Young Adult

OBJECTIVE: To explore prevalence, incidence and possible factors of immediate herniated discs after posterior cervical expansive open-door laminoplasty (EODL). METHODS: Totally 29 patients with cervical spinal stenosis and intervertebral disc herniation who underwent EODL from October 2020 to December 2021 were collected, including 24 males and 5 females, aged from 43 to 81 years old with an average of (61.3±9.0) years old;the courses of disease ranged from 1 to 120 months with an average of (36.4±37.0) months. Three or more intervertebral discs on C₃-C₇ were observed. The clinical efficacy was evaluated according to Japanese Orthopaedic Association (JOA) score before operation, 3 days and 1, 3, 6 and 12 months after operation, respectively. The changes of herniated disc before and after operation were measured by multipoint area method and two-dimensional distance method, and incidence and percentage of herniated disc regression were further calculated. Cervical imaging parameters such as Cobb angle (C₃-C₇), intervertebral angle, T₁ slope (T₁S), spinal canal sagittal diameter, K-line angle, dural sac sagittal diameter were measured and compared before and after operation. Pearson correlation was used to analyze correlation between cervical sagittal imaging parameters and disc herniation changes before and after operation. RESULTS: All patients obtained grade A wound healing, and 14 of them were followed up for 3(1.00, 5.25) months. There were no immediate or long-term postoperative complications. Totally 101 herniated intervertebral discs were measured, of which 79 regression numbers were obtained by area measurement. The number of intervertebral disc regressions by distance measurement was 77. There was no statistically significant difference in Cobb angle, intervertebral angle, T₁S and K-line angle of C₃-C₇ (P>0.05), however, there were statistically significant differences in sagittal diameter of spinal canal, sagittal diameter of dural sac, and JOA score before and after operation(P<0.05). The regression ratio of disc herniation ranged from 5% to 50%, and regression ratio of disc herniation was greater than 25% in 45.57%(36/79). Disc herniation in C_4,5 was positively correlated with sagittal plane diameter in C₅(r=0.423, P=0.028). There was a negative correlation between changes of C_3,4 and C_3,4 intervertebral angle (r=-0.450, P=0.041). The improvement rate of cervical JOA score immediately after operation was (59.54±15.07) %, and postoperative follow-up improved to (76.57±14.66) %. CONCLUSION Herniated disc regression immediately after EODL is a common occurrence, and EODL should be selected as far as possible under the premise of satisfying surgical indications. The regression of disc herniation is positively correlated with spinal canal sagittal diameter, and spinal canal should be enlarged as far as possible in the appropriate scope during EODL, so as to create more opportunities and conditions for disc regression and achieve better clinical results.
Humans ; Female ; Male ; Intervertebral Disc Displacement/diagnostic imaging* ; Spinal Stenosis/diagnostic imaging* ; Laminoplasty/methods* ; Middle Aged ; Aged ; Cervical Vertebrae/diagnostic imaging* ; Adult ; Aged, 80 and over ; Intervertebral Disc/surgery*

OBJECTIVE: To investigate the clinical value of MRI modified water-lipid separation technique (mDIXON-Quant) in terms of T2* values and fat fraction (FF) values for evaluating the degree of cervical intervertebral disc degeneration. METHODS: A total of 118 patients who underwent routine MRI of the cervical vertebra and the mDIXON-Quant examination in Fuyang People's Hospital from March 2019 to January 2024 were collected. The T2* values of C2/3 to C6/7 intervertebral discs and FF values of the upper and lower vertebral bodies were measured. Cervical intervertebral disc degeneration was graded according to the Pfirrmann criteria. The T2* values and FF values of different patients were compared with the Pfirrmann grades, and the correlation between T2* values, FF values, and Pfirrmann grades was analyzed by Spearman correlation. RESULTS: The T2* values of cervical intervertebral discs in grades I, II, III, IV, and V all showed a decreasing trend ( P＜0.05). The decreasing order of FF values in the upper cervical vertebra was IV, V, III, II, and I ( F=93.28, P＜0.05), and the decreasing order of FF values in the lower cervical vertebra was IV, III, V, II, and I ( F=112.037, P＜0.05). Spearman correlation analysis showed that the T2* values of cervical intervertebral discs were negatively correlated with the Pfirrmann grades ( P＜0.05), and the FF values of the upper and lower vertebrae were positively correlated with the Pfirrmann grades ( P＜0.05). CONCLUSION The mDIXON-Quant technique can be used to quantify the T2* values and FF values of cervical intervertebral disc degeneration and plays an important role in accurate clinical diagnosis and evaluation of treatment effects.
Humans ; Intervertebral Disc Degeneration/diagnostic imaging* ; Cervical Vertebrae/diagnostic imaging* ; Magnetic Resonance Imaging/methods* ; Male ; Female ; Middle Aged ; Adult ; Intervertebral Disc/diagnostic imaging* ; Lipids

OBJECTIVE: To explore clinical symptoms and X-ray imaging features of cervical instability in young adult represented by postgraduates with a master's degree in medicine. METHODS: Totally 91 postgraduates with a master's degree in medicine were investigated from September to December 2021, including 45 males and 46 females;aged from 22 to 30 years old with an average of (25.30±2.18) years old. The cervical spondylosis-related discomfort symptoms of the subjects were collected and examined by the examiner for neck and shoulder tenderness point examination and cervical vertebra positive and lateral and functional X-ray radiography. According to the results of X-ray examination, the subjects were divided into stable cervical group and unstable cervical group. RESULTS: Among 91 subjects, there were 50 patients with cervical instability, accounting for 54.90% of total number of subjects. The cervical curvature was abnormal in 78 patients, accounting for 85.70% of total number of subjects. Among 50 patients with cervical instability, 50 patients were diagnosed as cervical instability on the basis of angular displaxement(AD)≥ 11 °, including 13 cases of C_3,4 instability, 30 cases of C_4,5 instability and 7 cases of C_5,6 instability;and 5 cases were diagnosed as cervical instability based on horizontal displacement(HD)≥ 3.5 mm, including 1 case of C_3,4 instability and 4 cases of C_4,5 instability. Compared with stable cervical group, the number of discomfort symptoms of neck pain, headache and shoulder pain in instability group was significantly higher than that of in stable cervical group(P<0.05);and the number of tenderness in spinous process space of C_4,5 and C_5,6, 2 cm adjacent to the spinous process of C₂-C₅ and the superior angle of the scapula (the stop point of levator scapulae) in the instability group was significantly higher than that in the stable cervical group (P<0.05);and the cervical curvature in the instability group was significantly lower than that in stable cervical group(P<0.05). CONCLUSION The incidence of cervical instability in young adult represented by postgraduates with a master's degree in medicine is high, they are mainly diagnosed as cervical instability on the basis of vertebral angular displacement ≥ 11°, and the instability segments are concentrated on C_3,4, C_4,5 and C_5,6 segments, the occurrence of cervical instability is often accompanied by abnormalities of cervical curvature. Most of clinical manifestations are head, neck and shoulder pain, especially neck pain in unstable segment.
Male ; Female ; Humans ; Young Adult ; Adult ; Neck Pain/etiology* ; Shoulder Pain ; Spinal Diseases ; Radiography ; Spondylosis/diagnostic imaging* ; Joint Instability/diagnostic imaging* ; Cervical Vertebrae/diagnostic imaging*

OBJECTIVE: To explore the normal distribution of cervical sagittal alignment and the relationship between cervical alignment and global spine balance in asymptomatic young adults. METHODS: A cohort of 272 asymptomatic Chinese adults (including 161 males and 111 females, with an average age of (23.2±4.4) years, ranging from 18 to 45 years) were prospectively recruited from November 2011 to December 2014. The C₀-C₂ angle, disk angles from C₂-C₃ to C₆-C₇, vertebral angles from C₃ to C₇, T₁ slope, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), C₂-C₇ sagittal vertical axis (C₂-C₇SVA), center of gravity of head to C₇SVA (CGH-C₇SVA), C₇-S₁SVA were measured and statistically analyzed. All the subjects were categorized with the Roussouly classification and the cervical morphologies were evaluated as lordotic, straight, sigmoid or kyphotic. Spinal sagittal alignment parameters were compared between different sexes and Roussouly classifications with independent student t test, analysis of variance (ANOVA) or Chi-square test. Correlations between cervical sagittal alignment and global spine sagittal alignment were calculated using the Pearson and Spearman correlation coefficient. Linear regression analysis was performed. RESULTS: Sixty-seven males and 59 females aged from 18 to 30 years old were included in the study. The mean value of C₀-C₇ was 26.0°±12.8°, composed of 15.2°±6.7° for C₀-C₂, 9.1°±12.1° for sum of disk angles from C₂-C₃ to C₆-C₇, and 1.4°±10.2° for sum of vertebral angles from C₃ to C₇. C₂-C₇SVA [(18.6±7.9) mm] and CGH-C₇SVA [(22.9±12.3) mm]were offset ideally by C₇-S₁SVA [(-21.6±31.0) mm]. Males had a larger T₁ slope (P < 0.05) and accordingly, a larger cervical lordosis C₂-C₇ (P < 0.01) and C₀-C₇ angle (P < 0.01) than females. Males had a smaller C₇-S₁SVA (P < 0.01) and accordingly, a smaller CGH-C₇SVA (P=0.165) than females. Significant difference was found between cervical alignment of different Roussouly types (P < 0.01). In general, a larger LL was consistent with a set of larger TK, C₂-C₇angle, C₀-C₇ angle, and vice versa. There was no significant correlation between cervical morphology and the Roussouly classification (Chi-square=10.548, P=0.308). There was significant correlation between cervical alignment and T₁ slope (P < 0.01), TK (P < 0.01). There was significant correlation between adjacent segmental angles from T₁ slope up to C₀-C₂ angle (P < 0.05). CONCLUSION Normative values of each vertebral angle and disk angle were established. The cervical lordosis occurred mainly at C₀-C₂ and disk levels, which was influenced by parameters of other parts of the spine, such as T₁ slope, TK and the Roussouly classification. There was significant correlation between adjacent disk angles.
Adolescent ; Adult ; Cervical Vertebrae/diagnostic imaging* ; China ; Female ; Humans ; Kyphosis ; Lordosis/diagnostic imaging* ; Male ; Thoracic Vertebrae ; Young Adult