Background::Artificial intelligence (AI) technology represented by deep learning has made remarkable achievements in digital pathology, enhancing the accuracy and reliability of diagnosis and prognosis evaluation. The spatial distribution of CD3 + and CD8 + T cells within the tumor microenvironment has been demonstrated to have a significant impact on the prognosis of colorectal cancer (CRC). This study aimed to investigate CD3 CT (CD3 + T cells density in the core of the tumor [CT]) prognostic ability in patients with CRC by using AI technology. Methods::The study involved the enrollment of 492 patients from two distinct medical centers, with 358 patients assigned to the training cohort and an additional 134 patients allocated to the validation cohort. To facilitate tissue segmentation and T-cells quantification in whole-slide images (WSIs), a fully automated workflow based on deep learning was devised. Upon the completion of tissue segmentation and subsequent cell segmentation, a comprehensive analysis was conducted.Results::The evaluation of various positive T cell densities revealed comparable discriminatory ability between CD3 CT and CD3-CD8 (the combination of CD3 + and CD8 + T cells density within the CT and invasive margin) in predicting mortality (C-index in training cohort: 0.65 vs. 0.64; validation cohort: 0.69 vs. 0.69). The CD3 CT was confirmed as an independent prognostic factor, with high CD3 CT density associated with increased overall survival (OS) in the training cohort (hazard ratio [HR] = 0.22, 95% confidence interval [CI]: 0.12–0.38, P <0.001) and validation cohort (HR = 0.21, 95% CI: 0.05–0.92, P = 0.037). Conclusions::We quantify the spatial distribution of CD3 + and CD8 + T cells within tissue regions in WSIs using AI technology. The CD3 CT confirmed as a stage-independent predictor for OS in CRC patients. Moreover, CD3 CT shows promise in simplifying the CD3-CD8 system and facilitating its practical application in clinical settings.

Objective:To explore the efficacy of stage I modified posterior vertebral column resection (mPVCR) in the treatment of postoperative infection after percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fracture (OVCF).Methods:A retrospective case series study was conducted to analyze the clinical data of 11 OVCF patients with post-PVP infection who were admitted to Zhengzhou Orthopedics Hospital from January 2016 to June 2022, including 4 males and 7 females, aged 61-81 years [(70.2±6.4)years]. Injured segments included T 9 in 1 patient, T 11 in 2, T 12 in 3, L 1 in 1, L 2 in 2, T 11-T 12 in 1, and T 12-L 1 in 1. American Spinal Injury Association (ASIA) grading was grade D in 5 patients and grade E in 6. All the patients were treated with stage I mPVCR. The operation time and intraoperative bleeding volume were recorded. The values of Visual Analogue Scale (VAS), Oswestry Dysfunction Index (ODI), and Cobb angle of the lesion segments before, at 2 weeks, 3 months after surgery, and at the last follow-up were compared. The loss of Cobb angle of the lesion segments at 2 weeks after surgery and at the last follow-up were compared, and the ASIA grading at the last follow-up was recorded. The infection control, bone healing, and the incidence of complications were observed at the last follow-up. Results:All the patients were followed up for 12-44 months [(26.0±9.4)months]. The operation time and intraoperative bleeding volume were 230-330 minutes [(279.2±28.6)minutes] and 500-1 100 ml [(840.9±184.1)ml] respectively. At 2 weeks, 3 months after surgery and at the last follow-up, the VAS scores were (4.0±0.8)points, (2.7±0.9)points, and (2.4±0.7)points respectively, which were all lower than that before surgery [(8.1±1.2)points] ( P<0.01); the ODI was (45.5±5.1)%, (30.0±6.5)%, and (18.5±3.6)% respectively, which were all lower than that before surgery [(78.7±6.2)%] ( P<0.01); the Cobb angle of the lesion segments were (7.9±1.4)°, (8.5±1.4)°, and (9.2±1.5)° respectively, which were lower than that before surgery [(25.5±9.2)°] ( P<0.01). The VAS and ODI were both improved at 3 months after surgery compared with those at 2 weeks after surgery ( P<0.05), while there was no significant difference in Cobb angle of the lesion segments ( P>0.05). The ODI was further improved at the last follow-up compared with that at 3 months after surgery ( P<0.05), while there were no significant differences in VAS or Cobb angle of the lesion segments ( P>0.05). The loss of Cobb angle correction of the lesion segment at the last follow-up was 0.96 (0.69, 1.45)° compared with that at 2 weeks after surgery and the rate of loss of Cobb angle correction of the lesion segment was 4.4(2.2, 7.4)%. At the last follow-up, the ASIA grading was grade E for all the patients, who were able to walk normally independently. The infection was all cured and good bony fusion was observed in the operated area at the last follow-up. Two patients had pleural effusion and pulmonary atelectasis, 1 incision fat liquefaction, and 1 pneumonia after the surgery. None of the patients had internal fixation failure and serious complications such as worsening neurological symptoms or death. Conclusion:Stage I mPVCR for the treatment of post-PVP infection in patients with OVCF is proved to attain significant pain relief and functional improvement, good correction results, effective reconstruction of spinal stability, complete removal of infected lesions, and few serious complications.

Objective:To investigate the efficacy of one-stage posterior-anterior combined operation for the treatment of abnormal fusion after facet joint dislocation in the subaxial cervical spine.Methods:A retrospective study of case series was conducted to analyze the clinical data of 10 patients with abnormal fusion after facet joint dislocation in the subaxial cervical spine who had been admitted to Department of Spine Surgery, Zhengzhou Orthopedic Hospital from January 2015 to May 2023. There were 7 males and 3 females with an age of (41.2±3.1) years. Preoperative American Spinal Injury Association (ASIA) grading: 5 cases of grade A, 4 cases of grade B, and 1 cases of grade C. All the patients were treated with one-stage posterior-anterior combined operation. The surgical time and intraoperative bleeding volume were recorded. The ASIA grading was used to evaluate the improvements in nerve function of the spinal cord 3 months after surgery. The VAS scores, cervical intervertebral heights, and Cobb angles were compared between pre-surgery, 3 months after surgery, and the last follow-up. The fusion of intervertebral bone graft was evaluated 3 months after surgery using the Bridgell intervertebral fusion criteria. Complications were observed.Results:All patients were followed up for 15.5 (13.8, 20.5) months. The surgical time was (119.5±3.6) minutes, and the intraoperative bleeding volume (141.6±25.6) mL. Significant improvements in VAS score, cervical intervertebral height, and Cobb angle were observed at 3 months after surgery and the last follow-up compared with the pre-surgery values ( P<0.05), but there was no statistically significant difference between 3 months after surgery and the last follow-up ( P>0.05). ASIA grading 3 months after surgery: 4 cases of grade A, 4 cases of grade B, and 2 cases of grade C. By the Bridgell intervertebral fusion criteria at 3 months after surgery: 9 cases of grade Ⅰ and 1 cases of grade Ⅱ, showing good intervertebral fusion. Surgery went on well for all patients, showing no postoperative complications such as aggravation of nerve lesion or vascular injury. Conclusion:In the treatment of abnormal fusion after facet joint dislocation in the subaxial cervical spine, the efficacy of one-stage posterior-anterior combined operation is definite because it can effectively reduce pain, restore the height and physiological curvature of the cervical intervertebral space, and achieve good intervertebral fusion.

Objective:To evaluate the application of digital visualization in preoperative planning for surgical clearance of vertebral infection lesions following percutaneous vertebroplasty (PVP).Methods:A retrospective study was conducted to analyze the 13 patients with infectious spondylitis following PVP who had undergone one-stage posterior debridement and interbody bone grafting combined with instrumentation at Department of Spinal Surgery, Zhengzhou Orthopaedics Hospital from January 2016 to December 2022. They were 4 males and 9 females with an age of (71.4±6.5) years. Before surgery, the CT raw data of the patients were imported into software Mimics to reconstruct a three-dimensional model of the spine. After the distribution of bone cement in the model and its relationships with the vertebral plate, pedicle, articular process, and spinal cord were observed, a safe area for spinal canal surgery was designed. Intraoperative operations were carried out according to the preoperative planning. Surgical time, intraoperative blood loss, improvements in American Spinal Injury Association (ASIA) grading, and postoperative complications were recorded. The therapeutic efficacy was evaluated by comparisons of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), visual analogue scale (VAS), and Oswestry disability index (ODI) between preoperation, 2 weeks and 3 months postoperation, and the last follow-up.Results:Surgery went on successfully in all the 13 patients according to the preoperative planning. The surgical time was (275.9±28.3) min and the intraoperative blood loss (865.4±183.0) mL. All patients were followed up for (24.7±9.4) months. The levels of ESR, CRP, VAS, and ODI at 2 weeks, 3 months and the last follow-up were significantly lower than those before surgery ( P<0.05). At the last follow-up, X-ray and CT examinations showed good positions of internal fixation and sufficient bone graft fusion. The ASIA grading recovered from preoperative D to E in 5 patients. No incision infection, sinus formation, worsening of neurological symptoms, loosening or rupture of internal fixation, or worsening of neurological dysfunction were found. Conclusion:With the assistance of 3D visualization, the spinal cord, bone cement, and debridement area can be visualized directly to reduce nerve injury complications so that a safe and effective preoperative planning can be made for surgical clearance of vertebral infection lesions following PVP.

Objective:To investigate the efficacy of the classified reduction based on CT two-dimensional images for the surgical treatment of single segment facet joint dislocation in subaxial cervical spine.Methods:A retrospective case series study was made on 105 patients with single segment facet joint dislocation in subaxial cervical spine admitted to Zhengzhou Orthopedic Hospital from January 2015 to October 2022. There were 63 males and 42 females, with the age range of 22-78 years [(47.5±3.6)years]. Preoperative American Spinal Cord Injury Association (ASIA) classification was grade A in 23 patients, grade B in 45, grade C in 22, grade D in 15 and grade E in 0. The classification of surgical approach was based on the presence or not of continuity between anterior and posterior subaxial cervical structures and the movability of the posterior cervical facet joint on CT two-dimensional images, including anterior cervical surgery if both were presented and posterior facet joint resection plus anterior cervical surgery if there was discontinuity between anterior and posterior subaxial cervical structures or posterior facet joint fusion. Reduction procedures were applied in accordance with the type of facet joint dislocation classified based on the position of the lower upper corner of facet joint, including skull traction or manipulative reduction for the dislocation locating at the dorsal side (type A), intraoperative skull traction and leverage technique for the dislocation locating at the top (type B) and intraoperative skull traction and leverage technique with boosting for the dislocation locating at the ventral side (type C). If the dislocation of two facet joints in the same patient was different, the priority of management followed the order of type C, type B and type A. The reduction success rate, operation time and intraoperative blood loss were recorded. The cervical physiological curvature was evaluated by comparing the intervertebral space height and Cobb angle before operation, at 3 months after operation and at the last follow-up. The fusion rate of intervertebral bone grafting was evaluated by Lenke grading at 3 months after operation. The spinal cord nerve injury was assessed with ASIA classification before operation and at 3 months after operation. Japanese Orthopedic Association (JOA) score was applied to measure the degree of cervical spinal cord dysfunction before operation and at 3 months after operation, and the final follow-up score was used to calculate the rate of spinal cord functional recovery. The occurrence of complications was observed.Results:All patients were followed up for 3-9 months [(6.0±2.5)months]. The reduction success rate was 100%. The operation time was 40-95 minutes [(58.6±9.3)minutes]. The intraoperative blood loss was 40 to 120 ml [(55.7±6.8)ml]. The intervertebral space height was (4.7±0.3)mm and (4.7±0.2)mm at 3 months after operation and at the last follow-up, significantly decreased from preoperative (3.1±0.5)mm (all P<0.01), but there was no significant difference in intervertebral space height at 3 months after operation and at the last follow-up ( P>0.05). The Cobb angle was (6.5±1.3)° and (6.3±1.2)° at 3 months after operation and at the last follow-up, significantly increased from preoperative (-5.4±2.2)° (all P<0.01), but there was no significant difference in Cobb angle at 3 months after operation and at the last follow-up ( P>0.05). The fusion rate of intervertebral bone grafting evaluated by Lenke grading was 100% at 3 months after operation. The ASIA grading was grade A in 15 patients, grade B in 42, grade C in 29, grade D in 12 and grade E in 7 at 3 months after operation. The patients showed varying degrees of improvement in postoperative ASIA grade except that 15 patients with preoperative ASIA grade A had partial recovery of limb sensation but no improvement in ASIA grade. The JOA score was (13.3±0.6)points and (13.1±0.6)points at 3 months after operation and at the last follow-up, significantly improved from preoperative (6.8±1.4)points (all P<0.01), but there was no significant difference in JOA score at 3 months after operation and at the last follow-up ( P>0.05). The rate of spinal cord functional recovery was (66.3±2.5)% at the last follow-up. All patients had no complications such as increased nerve damage or vascular damage. Conclusion:The classified reduction based on CT two-dimensional images for the surgical treatment of single segment facet joint dislocation in subaxial cervical spine has advantages of reduced facet joint dislocation, recovered intervertebral space height and physiological curvature, good intervertebral fusion and improved spinal cord function.

Objective:To compare the clinical efficacies of precision targeted and traditional percutaneous vertebroplasty (PVP) in the treatment of refracture of injured vertebra after operation for Kümmell disease.Methods:A retrospective cohort study was conducted to analyze the clinical data of 23 Kümmell disease patients suffering from refracture of injured vertebra after PVP in Zhengzhou Orthopedic Hospital from October 2014 to October 2018. The patients included 7 males and 16 females, aged 53-89 years [(69.3±3.5)years]. There were 11 patients of stage I Kümmell disease and 12 patients of stage II Kümmell disease. The vertebral distribution of fracture was T 11 (3 patients), T 12 (9 patients), L 1 (8 patients) and L 2 (3 patients). Eleven patients received traditional PVP treatment (traditional PVP group) and 12 patients received precision targeted PVP treatment (targeted PVP group). The operation time, amount of bone cement injection and filling of bone cement in the fracture space were compared between the two groups. The visual analogue score (VAS) and Oswestry disability index (ODI) were also compared before operation, at 2 days, 1 month, 3 months, 6 months after operation, and at the last follow-up. The rates of bone cement leakage and re-collapse of injured vertebra were observed in the two groups. Results:The patients were followed up for 12-36 months [(24.2±2.6)months]. There were no significant differences in the operation time or amount of bone cement injection between the two groups (all P>0.05). All the fracture spaces in the targeted PVP group were fully filled with bone cement, while 4 patients in the traditional PVP group showed inadequate filling of the fracture area ( P<0.05). The VAS values in the targeted PVP group were (8.9±0.5)points, (1.6±0.2)points, (1.7±0.1)points, (1.8±0.1)points, (1.9±0.3)points, and (1.8±0.4)points before operation, at 2 days, 1 month, 3 months, 6 months after operation and at the last follow-up; and those in the traditional PVP group were (9.1±0.9)points, (1.8±0.4)points, (1.8±0.2)points, (2.0±0.4)points, (2.1±0.2)points, and (2.4±0.3)points, respectively. The VAS values of both groups were significantly decreased at 2 days, 1 month, 3 months, 6 months after operation, and at the last follow-up compared with those before operation (all P<0.05), but there was no significant difference between different time points after operation (all P>0.05). No significant differences were found in the VAS values between the two groups before operation and at 2 days, 1 month, 3 months and 6 months after operation (all P>0.05). However, the VAS value in the targeted PVP group was significantly lower than that in the traditional PVP group at the last follow-up ( P<0.05). The ODI values in the targeted PVP group were 38.5±4.3, 7.2±2.3, 7.3±2.0, 7.2±1.8, 7.3±2.4, and 7.4±2.5 before operation and at 2 days, 1 month, 3 months, 6 months after operation, and at last follow-up; and those in the traditional PVP group were 37.8±4.1, 7.5±2.5, 7.7±1.9, 7.9±2.4, 8.1±2.6, and 9.6±2.4, respectively. The ODI values of both groups were significantly decreased at 2 days, 1 month, 3 months, 6 months after operation and at the last follow-up compared with those before operation (all P<0.05), but there were no significant differences between different time points after operation (all P>0.05). The ODI values were not significantly different between the two groups before operation and at 2 days, 1 month, 3 months, 6 months after operation (all P>0.05), but the ODI value in the targeted PVP group was significantly lower than that in the traditional PVP group at the last follow-up ( P<0.05). There were no significant differences in the rates of bone cement leakage or re-collapse of injured vertebra between the two groups (all P>0.05). Conclusion:Compared with traditional PVP treatment for refracture of injured vertebra after operation for Kümmell disease, targeted PVP can make bone cement injection fully dispersed, greatly reduce pain and promote functional recovery.

Objective:To compare the efficacies of posterior long segment instrumentation combined with transpedicular impaction bone grafting or with bone cement augmentation in treating stage III Kümmell disease.Methods:A retrospective cohort study was conducted to analyze the clinical data of 38 patients with stage III Kümmell disease who were admitted to Zhengzhou Orthopedic Hospital between January 2016 and December 2020. The study included 8 male and 30 female patients, with ages ranging from 59 to 81 years [(68.9±4.9)years]. The vertebral fractures occurred at T 8 in 1 patient, T 11 in 9 patients, T 12 in 10 patients, and L 2 in 10 patients. Seventeen patients underwent posterior long segment instrumentation combined with transpedicular impaction bone grafting (impaction bone grafting group), and 21 patients underwent posterior long segment instrumentation combined with bone cement augmentation (bone cement group). The surgical duration, intraoperative blood loss, and incidences of postoperative complications were compared between the two groups. Additionally, the visual analogue score (VAS), Japanese orthopedic association (JOA) score, and Cobb angle were compared before the operation, at 1 week and 3 months post-operation, and at the final follow-up for both groups. The study also compared bone healing at the last follow-up and postoperative complication rates between the two groups. Results:All the patients were followed up for 24-35 months [(28.7±2.9)months]. The impaction bone grafting group had a surgical duration of (150.7±25.4)minutes and intraoperative blood loss of (285.3±48.6)ml, significantly different from those in the bone cement group [(132.0±21.1)minutes, (251.4±44.8)ml] (all P<0.05). Before the operation, there were no significant differences in the VAS, JOA score, or Cobb angle between the two groups (all P>0.05).The VAS was (3.2±0.8)points, (2.7±0.5)points and (2.2±0.7)points in the impaction bone grafting group and was (2.7±0.6)points, (2.6±0.7)points and (2.4±0.8)points in the bone cement group at 1 week and 3 months post-operation and at the final follow-up, respectively. The VAS in the impaction bone grafting group was significantly higher than that in the bone cement group at 1 week post-operation ( P<0.05); however, no significant differences were found at 3 months post-operation or at the last follow-up (all P>0.05). There was no significant difference in the JOA score between the two groups at 1 week or 3 months post-operation, or at the final follow-up (all P>0.05). The Cobb angle in the impaction bone grafting group was (5.1±1.3)°, (5.9±1.8)° and (6.5±2.5)° at 1 week and 3 months post-operation, and at the final follow-up, significantly lower than that in the bone cement group [(8.4±1.6)°, (12.6±2.1)°, and (14.5±3.3)°] (all P<0.01). All the patients in the impaction bone grafting group achieved bone healing at the last follow-up. One patient in the impaction bone grafting group experienced delayed incision healing, whereas two patients in the bone cement group had poor bone healing. The complication rate was 5.9% (1/17) in the impaction bone grafting group and 9.5% (2/21) in the bone cement group ( P>0.05). Conclusions:Posterior long segment instrumentation combined with transpedicular impaction bone grafting or with bone cement augmentation are both effective in alleviating pain and improving the spinal function for stage III Kümmell disease. The former procedure is associated with longer surgical duration and increased intraoperative blood loss, but it can provide superior correction and maintenance of kyphosis deformity, promoting the healing of the injured vertebrae.

Objective:To compare the clinical effect of transpedicular impaction and grafting of allogeneic bone containing enriched bone marrow combined with posterior internal fixation and posterior subtotal vertebrectomy combined with posterior internal fixation in the treatment of stage III Kümmell′s disease.Methods:A retrospective cohort study was made on clinical data of 40 patients with stage III Kümmell′s disease admitted to Zhengzhou Orthopedic Hospital from June 2015 to December 2018. There were 10 males and 30 females, at age range of 57-79 years［(67.7±6.1)years］. A total of 19 patients were treated by transpedicular impaction and grafting of allogeneic bone containing enriched bone marrow combined with posterior internal fixation (impaction bone graft group), and 21 patients by posterior subtotal vertebrectomy combined with posterior internal fixation (subtotal vertebrectomy group). Operation time and intraoperative blood loss were compared between the two groups. Degree of pain, lumbar dysfunction and degree of kyphosis were evaluated by visual analogue scale (VAS), Japanese Orthopedic Association (JOA) score and kyphotic Cobb angle before operation, at 1 week after operation and at the last follow-up. Bone healing time was compared between the two groups. The complications of the two groups were observed.Results:All patients were followed up for 25-64 months［(40.6±10.4)months］. Operation time and intraoperative blood loss were (130.0±10.1)minutes and (284.5±43.5)ml in impaction bone graft group, lower than those in subtotal vertebrectomy group［(253.8±33.2)minutes, (889.1±95.7)ml］(both P<0.01). There were no significant differences in VAS, JOA score or kyphotic Cobb angle between the two groups before operation, at 1 week after operation and at the last follow-up (all P>0.05). Both VAS and JOA score showed significant differences within each group at any time point (all P<0.01). In both groups, the kyphotic Cobb angle reduced significantly at 1 week after operation when compared with that before operation (all P<0.01), and the angle showed a slight increase at the last follow-up, but remained significantly lower than that before operation (all P<0.01). There were no relapse of pain or aggravation of kyphosis. Bone healing time in impaction bone graft group［4.4(4.0, 5.0)months］was significantly shorter than that in subtotal vertebrectomy group［6.4(5.2, 8.1)months］( P<0.01). There were 2 patients with delayed healing of surgical incision in impaction bone graft group, with the complication rate of 11%. There were 2 patients with dural tear and 3 patients with delayed healing of surgical incision in subtotal vertebrectomy group, with the complication rate of 24%. The complication rate was not statistically significant between the two groups ( P>0.05). No loosening or breakage of internal fixation was observed during the follow-up. Conclusions:Transpedicular impaction and grafting of allogeneic bone containing enriched bone marrow combined with posterior internal fixation and posterior subtotal vertebrectomy combined with posterior internal fixation are effective in the treatment of stage III Kümmell disease. However, the former can shorten the operation time, reduce the intraoperative blood loss and accelerate the healing of injured vertebral bone, suggesting a relatively minimally invasive surgical method for reconstruction and maintenance of spinal biomechanical stability.

Objective:To compare the clinical efficacy of long/short segment posterior instrumentation combined with transpedicular impaction bone grafting for stage III Kümmell's disease.Methods:A retrospective case control study was conducted to analyze the clinical data of 45 patients with stage III Kümmell's disease admitted to Zhengzhou Orthopaedics Hospital from June 2012 to June 2019, There were 8 males and 37 females, aged 58-84 years [(68.8±3.5)years]. Segment of injury was T 11 in 5 patients, T 12 in 18, L 1 in 15, and L 2 in 7. A total of 24 patients were treated with posterior long segment pedicle screw fixation combined with pedicle screw compression and bone grafting (long segment group), and 21 patients were treated with posterior short segment pedicle screw fixation combined with pedicle screw compression and bone grafting (short segment group). For patients with severe osteoporosis, pedicle screws were augmented with bone cement. The operation time and blood loss were compared between the two groups. The visual analogue scale (VAS) was used to evaluate the degree of low back pain, and the Japanese Orthopaedic Association (JOA) score was used to evaluate the lumbar function at postoperative 2 weeks and 1 year. According to X-ray film and CT examination, the bone healing of the grafted vertebral body and the changes of Cobb angle of injured vertebrae were further evaluated. The complications were observed. Results:All patients were followed up for 15-48 months[(31.2±2.3)months]. There were no significant differences between the two groups in operation time and intraoperative blood loss ( P>0.05). The bone grafts in the vertebrae healed well in both groups at 1 year after operation. The Cobb angle, VAS and JOA score in both groups improved at 2 weeks and 1 year after operation ( P<0.01). There was no significant difference in Cobb angle, VAS and JOA score between the two groups at 2 weeks after operation ( P>0.05). The Cobb angle in short segment group [(14.8±6.3)°] was significantly higher than that in long segment group [(8.5±3.3)°] at 1 year after operation ( P<0.01), but there was no significant difference in VAS and JOA scores between the two groups ( P>0.05). There was no loosening or breakage of internal fixation in both groups. Conclusions:For stage III Kümmell's disease, both long and short segment posterior instrumentation combined with transpedicular impaction bone grafting can effectively restore the vertebral height, improve kyphosis and reduce dysfunction. However, long segment can better maintain spine stability, prevent vertebral collapse and progression of local kyphosis Cobb angle when compared with short segment fixation.

Objective:To investigate the efficacy of stage I anterior cervical reduction, decompression, interbody fusion and internal fixation of single-segment lower cervical injury of AO type C subtype F4.Methods:A retrospective case series study was made on 45 patients with single-segment lower cervical injury of AO C type F4 subtype admitted to Zhengzhou Orthopedic Hospital from January 2012 to December 2019. The study included 31 males and 14 females with the age of (48.5±3.7)years (range, 23-78 years). Segment of injury was located at C 4/5 in 11 patients, at C 5/6 in 19, and at C 6/7 in 15. Under general anesthesia, all patients (16 unilateral injury and 29 bilateral injury) underwent stage I anterior cervical reduction, decompression, interbody fusion and internal fixation within 24 hours after injury. The interbody fusion methods included autogenous iliac bone in 28 patients and cervical fusion cage in 17. The operation time, blood loss, reduction time and correction rate of zygapophysial joints, postoperative complications and incision healing were analyzed. The height of cervical intervertebral space and Cobb angle were measured through X-ray of lateral cervical vertebrae before operation and3 months after operation to assess the cervical physiological curvature. The type of injury was clarified according to Lenke classification through coronal and sagittal CT scanning to determine the intervertebral bone graft fusion rate. The intraspinal spinal cord decompression was observed through MRI. The nerve function was assessed before operation and 3 months after operation using American Spinal Injury Association (ASIA) scale and Japanese Orthopedic Association (JOA) score, and the improvement rate was measured. Results:All the patients were followed up for (6.1±3.6)months (range, 3-9 months). The operation time was (55.1±8.2)minutes (range, 40-75 minutes), and intraoperative blood loss was (45.2±5.3)ml (range, 40-80 ml). The Zygapophysial joint reduction took (2.1±0.5)minutes (range, 1.5-3.0 minutes), with a success rate of 100%. Surgical procedures were performed with no postoperative complications such as aggravated spinal cord injury, large vascular injury or esophageal lesion. All the patients obtained Class I incision healing at first stage. The height of cervical intervertebral space was improved from preoperative (3.3±0.6)mm to (4.9±0.8)mm at postoperative 3 months ( P<0.05). The Cobb angle was increased from preoperative (-4.6±3.6)° to (6.5±2.1)° at postoperative 3 months ( P<0.01). According to Lenke classification, the intervertebral body fusion was good at postoperative 3 months, including Grade A in 41 patients and Grade B in 4. The rest of the patients showed varying degrees of neurological recovery according to ASIA scale, except for 6 patients with ASIA Grade A. The JOA score was improved from preoperative (7.4±2.3)points to (15.0±3.2)points at postoperative 3 months ( P<0.05), with the improvement rate of (73.3±17.6)%. Conclusion:For stage I anterior cervical reduction, decompression, interbody fusion and internal fixation of single-segment lower cervical injury of AO type C subtype F4, early surgical decompression is needed so as to reduce the perched facet or dislocated zygapophyseal joints and effectively improve the cervical spinal cord function.