Nomogram for predicting venous thromboembolism after spinal surgery.

PURPOSE: This study aimed to establish a nomogram to predict the risk of venous thromboembolism (VTE), identifying potential risk factors, and providing theoretical basis for prevention of VTE after spinal surgery. METHODS: A retrospective analysis was conducted on 2754 patients who underwent spinal surgery. The general characteristics of the training group were initially screened using univariate logistic analysis, and the LASSO method was used for optimal prediction. Subsequently, multivariate logistic regression analysis was performed to identify independent risk factors for postoperative VTE in the training group, and a nomogram for predict risk of VTE was established. The discrimination, calibration, and clinical usefulness of the nomogram were separately evaluated using the C-index, receiver operating characteristic curve, calibration plot and clinical decision curve, and was validated using data from the validation group finally. RESULTS: Multivariate logistic regression analysis identified 10 independent risk factors for VTE after spinal surgery. A nomogram was established based on these independent risk factors. The C-index for the training and validation groups indicating high accuracy and stability of the model. The area under the receiver operating characteristic curve indicating excellent discrimination ability; the calibration curves showed outstanding calibration for both the training and validation groups. Decision curve analysis showed the clinical net benefit of using the nomogram could be maximized in the probability threshold range of 0.01-1. CONCLUSION: Patients undergoing spinal surgery with elevated D-dimer levels, prolonger surgical, and cervical surgery have higher risk of VTE. The nomogram can provide a theoretical basis for clinicians to prevent VTE.

Retropharyngeal Reduction Plate for Atlantoaxial Dislocation: A Cadaveric Test and Morphometric Trajectory Analysis.

OBJECTIVE: To evaluate the placement feasibility and safety of the newly designed retropharyngeal reduction plate by cadaveric test and to perform morphometric trajectory analysis. METHODS: The five cadaveric specimens with intact atlantoaxial joint were enrolled in this study. They were used for simulating the placement process and evaluating the placement feasibility of the retropharyngeal reduction plate. The atlantoaxial dislocation (AAD) of five cadaveric specimens were obtained by proper external force after dissecting ligaments. The retropharyngeal reduction plate was placed on atlantoaxial joint of cadaveric specimens. The X-ray and three-dimensional (3D) spiral CT were used for evaluating the placement safety of retropharyngeal reduction plate. The DICOM data was obtained after 3D spiral CT scanning for the morphometric trajectory analysis. RESULTS: The reduction plates were successfully placed on the atlantoaxial joint of five cadaveric specimens through the retropharyngeal approach, respectively. The X-ray and 3D spiral CT showed the accurate screw implantation and satisfying plate placement. The length of the left/right atlas screw trajectory (L/RAT) was, respectively, 1.73 ± 0.01 cm (LAT) and 1.71 ± 0.02 cm (RAT). The length of odontoid screw trajectory (OST) was 1.38 ± 0.02 cm. The length of the left/right axis screw trajectory (L/RAXT) was, respectively, 1.67 ± 0.02 cm (LAXT) and 1.67 ± 0.01 cm (RAXT). There was no statistical significance between left side and right side in terms of AT and AXT (P > 0.05). The angles of atlas screw trajectory angle (ASTA), axis screw trajectory angle (AXSTA), and odontoid screw trajectory angle (OSTA) were 38.04° ± 2.03°, 56.92° ± 2.66°, and 34.78° ± 2.87°, respectively. CONCLUSION: The cadaveric test showed that the retropharyngeal reduction plate is feasible to place on the atlantoaxial joint, which is also a safe treatment choice for atlantoaxial dislocation. The meticulous preoperative planning of screw trajectory based on individual differences was also vital to using this technique.

Morphometric Trajectory Analysis for Occipital Condyle Screws.

OBJECTIVES: Occipitocervical fusion (OCF) is an effective treatment for instability of occipitocervical junction (OCJ). The occipital condyle screw serves as a novel surgical technique for occipitocervical fixation. However, the intraoperative procedures for the occipital condyle screw technique have relied on surgeons' experience, so the pool of surgeons who are able to perform this surgery safely is limited. The present study aims to evaluate the feasibility and safety of the occipital condyle screw technique using human cadavers and to provide image anatomy for clinical application basis. METHODS: The scientific study comprised 10 fresh-frozen cadaveric specimens from the anatomy department of Qingdao University. Placement of the occipital condyle screws (3.5 mm diameter and 20.0 mm length) was performed in the 10 fresh-frozen cadaveric specimens with intact occipitocervical junctions, respectively. Occipitocervical CT was performed for all specimens and the DICOM data was obtained. Occipitocervical CT three-dimensional (3D) reconstruction was performed for the cadavers. Morphometric analysis was performed on the bilateral occipitocervical junction of 10 cadaveric specimens based on the 3D reconstruction CT images. Detailed morphometric measurements of the 20 occipital condyles screws were conducted including the average length of the screw trajectory, inside and upper tilting angles of screws, distance to the hypoglossal canal, and to the medial wall of occipital condyle. RESULTS: Placement of the occipital condyle screws into the 20 occipital condyles of the 10 cadaveric specimens was performed successfully and the trajectory of implantation was satisfactory according to 3D CT reconstruction images, respectively. There was no obvious injury to the spinal cord, nerve root, and vertebral artery. The length of the bilateral screw trajectory was, respectively, 20.96 ± 0.91 mm (left) and 20.59 ± 0.77 mm (right) (t = 1.306, P > 0.05). The upper tilting angle of bilateral screws was, respectively, 11.24° ± 0.74° (left) and 11.11° ± 0.64° (right) (t = 0.681, P > 0.05). The inside tilting angle of bilateral screws was, respectively, 31.00° ± 1.32° (left) and 30.85° ± 1.27° (right) (t = 0.307, P > 0.05). The screw's distance to the bilateral hypoglossal canal was, respectively, 4.84 ± 0.54 mm (left) and 4.70 ± 0.54 mm (right) (t = 0.685, P > 0.05). The screw's distance to the medial wall of the bilateral occipital condyle was, respectively, 5.13 ± 0.77 mm (left) and 5.04 ± 0.71 mm (right) (t = 0.384, P > 0.05). CONCLUSION: The occipital condyle screw technique can serve as a feasible and safe treatment for instability of the occipitocervical junction with meticulous preoperative planning of the screw entry point and direction based on individual differences. Morphometric trajectory analysis is also an effective way to evaluate the surgical procedure.

Effects of AAV2-mediated co-transfection of CTGF and TIMP1 genes on degenerative lumbar intervertebral discs in rhesus monkeys in vivo.

OBJECTIVE: This study aims to investigate the effects of co-transfection of the genes for connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinase-1 (TIMP1) mediated by adeno-associated virus 2 (AAV2) on degenerative lumbar intervertebral discs in a primate model. METHODS: Twelve 4-7 year-old rhesus monkeys weighing 4.5-7.0 kg were utilized. CTGF and TIMP1 genes carried by AAV2 were injected into the degenerative lumbar intervertebral discs. Cytokine expression and biological effects were determined using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and 35S-sulfate incorporation assays. A rhesus monkey model of intervertebral disc degeneration was successfully established. RESULTS: At post-transfection, CTGF mRNA expression was higher in the transfection group than in the control group (P < 0.05). Furthermore, TIMP1 mRNA expression in the transfection group was several times the levels observed in the control group (P < 0.05). Moreover, type-II collagen mRNA expression was higher in the transfection group than in the control group (P < 0.05). In addition, higher aggrecan mRNA expression and synthesis were observed in the transfection group, compared to that in the control group (P < 0.05). CONCLUSION: The stable expression of CTGF and TIMP1 genes in vivo promoted the synthesis of aggrecan and type II collagen in the nucleus pulposus in the rhesus monkey model of intervertebral disc degeneration, which has a potential for intervertebral disc regeneration.

Sagittal Atlantoaxial Joint Inclination and Reduction Index Values for Diagnosis and Treatment of Irreducible Atlantoaxial Dislocation.

BACKGROUND: Irreducible atlantoaxial dislocation (IAAD) is a disorder of atlantoaxial joint instability with various causes. The diagnostic criteria for IAAD are variable. The diagnosis of IAAD is mainly based on preoperative and intraoperative traction results, as well as the physician's experience, with no relatively uniform guidelines for the selection of treatment. This study evaluates sagittal atlantoaxial joint inclination (SAAJI) and reduction index (RI) values for diagnosis and treatment of IAAD. MATERIALS AND METHODS: 24 IAAD patients treated in our hospital from January 2008 to July 2014 were retrospectively analysed. Patients included were 13 males and 11 females, with a mean age of 43 years. The various causes for IAAD were atlantoaxial transverse ligament rupture (n=3), old dens fracture (n=15), occipitalization of the atlas (n=6). The patients were divided into two groups. group A underwent anterior release with posterior reduction and fixation; Group B underwent posterior reduction and fixation; 12 healthy individuals served as controls. SAAJI and atlas-dens interval (ADI) values before and after traction were measured, and RI was calculated. Imaging data were analyzed. RESULTS: The mean SAAJI values were as follows: left, 5.6 ± 1.9° and right, 5.1 ± 2.1° in the control group; right, 39.5 ± 6.0° and left, 38.8 ± 5.8° in Group A; and right, 23.1 ± 7.0° and left, 23.9 ± 6.1° in Group B. There was no significant difference in the SAAJI values of the three groups (P < 0.05). The mean RIs in Groups A and B were 17.6 ± 9.3% and 34.4 ± 5.2%, respectively, and the difference was statistically significant (P < 0.05). There were obvious negative correlations between the SAAJI and RI values in Groups A and B. CONCLUSIONS: SAAJI and RI can be used as important imaging indicators to determine the reversibility of IAAD. If the RI value is >27.9% and SAAJI value is <32.5°, reduction and fixation can be achieved by the posterior approach alone; otherwise, a combination of anterior and posterior approaches would be necessary.

MiR-125a Rs12976445 Polymorphism is Associated with the Apoptosis Status of Nucleus Pulposus Cells and the Risk of Intervertebral Disc Degeneration.

BACKGROUND: Spinal degenerative diseases are a major health problem and social burden worldwide. Intervertebral disc degeneration (IDD) is the pathological basis of spinal degenerative diseases and is characterized by loss of nucleus pulposus cells due to excessive apoptosis caused by various factors. MicroRNAs (miRNAs) have been reported to be functionally involved in the control of apoptosis. METHODS: computational analysis and luciferase assay were used to identify the target of miR-125a, and cell culture, transfection were used to confirm such relationship. Sequencing was used to determine the genotype of each participant. RESULTS: We confirmed the previous report that the presence of the minor allele (T) of rs12976445 polymorphism significantly downregulated the expression level of miR-125a in nucleus pulposus cells, leading to less efficient inhibition of its target gene. We also validated TP53INP1 as a target of miR-125a in nucleus pulposus cells using a dual luciferase reporter system, and the transfection of miR-125a significantly reduced the expression of TP53INP1. The expression level of TP53INP1 was significantly lower in nucleus pulposus cells genotyped as CT or TT than in those genotyped as CC, and the apoptosis rate was consistently lower in the CC group than in the nucleus pulposus cells collected from individuals carrying at least one minor allele of rs12976445 polymorphism. To study the association between rs12976445 polymorphism and the risk of IDD, we enrolled 242 patients diagnosed with IDD and 278 normal controls, and significant differences were noted regarding the genotype distribution of rs12976445 between the IDD and the control groups (OR = 2.69, 95% C.I. = 1.88-3.83, p < 0.0001). In summary, rs12976445 polymorphism is significantly associated with the risk of IDD in the Chinese population. CONCLUSION: The present study indicated that miR-125a is a promising potential target for patients with IDD in clinical practice.

Thoracic intervertebral disc calcification and herniation in adults: a report of two cases.

PURPOSE: Acute paraplegia due to thoracic intervertebral disc protrusion and calcification is rare. The purpose of this study was to report two cases with acute paraplegia due to a calcified thoracic disc prolapse, and discuss its clinical diagnosis and surgical treatment with literature reviews. METHODS: These two cases were verified by patient history, physical examination, laboratory examination, CT and MRI studies, and pathological findings. RESULTS: CT scan revealed disc calcification and protrusion at the T11-12 level in case 1 and at the T10-11 level in case 2, respectively. MRI images revealed severe spinal cord compression with a hyperintense central core and surrounding hypointense area in two cases, which were directly connected to the calcified intervertebral nucleus pulposus. Pathological examination revealed calcium deposition. Patients underwent discectomy followed by interbody fusion, and satisfactory therapeutic outcomes were obtained. CONCLUSIONS: We suggest that decompression surgery should be carried out as early as possible for patients with early spinal myelopathy or paraplegia caused by a calcified protruded disc.

One stage laminoplasty and posterior herniotomy for the treatment of myelopathy caused by cervical stenosis with cervical disc herniation.

The aim of the study was to introduce a method of one stage laminoplasty and posterior herniotomy for myelopathy caused by cervical stenosis with cervical disc herniation and to evaluate the clinical efficacy of this surgery. From 1999 to 2008, 18 patients with myelopathy caused by cervical stenosis with cervical disc herniation who underwent this procedure were included. The average age was 63 years (range 48-74 years), and the average follow-up period was 46 months (range 3-108 months). Neurologic status was evaluated using the JOA scoring system. Neurological symptoms improvement was seen in all patients after surgery. The average JOA score was 14.22±1.86 by final follow-up, which was higher than preoperative values (P<0.01), and the average improvement in neurological function was 76.63%. Neurologic examination showed that excellent results had been obtained by 10 patients, good results by 8 patients, with no fair or poor results. 2 patients developed cerebrospinal fluid leakage after surgery and recovered during the follow-up period. One patient with cervical disc herniation developed postoperative C5 palsy on the axle side on the third day after surgery. She completely recovered by 1 month after surgery. No other patients experienced postoperative neurologic complications. Complete anterior and posterior decompression of the spinal cord was achieved after surgery. We concluded that one stage laminoplasty and posterior herniotomy is an effective, reliable, and safe procedure for the treatment of myelopathy caused by cervical stenosis with cervical disc herniation.

Single-stage combined anterior retropharyngeal and posterior approach for the resection and reconstruction of C2 metastatic tumors: A case report.

This study reports the case of a 44-year-old male who had experienced severe neck pain for one month and was diagnosed with a metastatic tumor of the left C2 vertebral body and the left transverse process. The tumor was distributed to layers A-D and sectors 3-7 according to the Weinstein-Boriani-Biagini classification, and was in Category IV according to the Harrington classification system. A conventional posterior cervical approach was used to resect the left transverse process and part of the tumor in a piecemeal fashion, and spinal instrumentation was also performed. Gelfoam and absorbable hemostatic gauze were placed ventrally to the left vertebral artery and the left C3 nerve root over the tumor bed to prevent their accidental injury in the subsequent anterior approach. A high anterior retropharyngeal approach was then used to resect the tumorous C2 vertebral body by corpectomy and to perform anterior reconstruction. Six months after the surgery, the patient remained pain free. Therefore, C2 metastatic tumor resection and spinal reconstruction can be fulfilled by a single-stage combined high anterior retropharyngeal and posterior approach.

Correction of post-traumatic thoracolumbar kyphosis using pedicle subtraction osteotomy.

The aim of this study was to retrospectively analyze and evaluate the effect of treatment employing pedicle subtraction osteotomy for chronic, posttraumatic thoracolumbar kyphosis. This study included 19 patients, 11 males and 8 females, with chronic, posttraumatic thoracolumbar kyphosis. Pre-operative kyphosis ranged from 31° to 63°. The history of trauma ranged from 8 to 63 months. All patients were treated with pedicle subtraction osteotomy. A mean 40.2° improvement in sagittal alignment was achieved with a mean correction rate of 85.8 %. Perioperative complications were encountered in two patients, one with cerebrospinal fluid leakage followed by encephalitic infection and one with a wound infection. Both were treated conservatively with antibiotics and local wound care. There were no other severe complications. The average follow-up period was 15 months (range 6-41 months). At the last follow-up, clinical symptoms and neurological function were significantly improved. Of 14 patients presenting with intractable back pain, VAS scores improved from a preoperative mean of 6.7 (range 5.0-8.0) to an average 2.0 (range 0-3.0) at final follow-up. No significant loss of correction was observed (loss of 1.7°), and solid fusion was achieved in all 19 patients. A single-stage posterior pedicle subtraction osteotomy is a safe and effective procedure for correction of posttraumatic thoracolumbar kyphosis. Using this technique, it is possible to safely obtain no greater than 55° of correction at a single level.

[Outcomes of posterior C(1-2) fusion for atlantoaxial instability or dislocation using pedicle screws of atlas and axis].

OBJECTIVE: To retrospectively analyze and evaluate the results of treatment for atlantoaxial instability or dislocation employing pedicle screws of atlas and axis. METHODS: Thirty-one patients (23 male and 8 female) with atlantoaxial instability or dislocation were stabilized using pedicle screws of atlas and axis between May 2005 to January 2008. The patients ranged in age from 17 to 67 years (mean 43.5 years). Patients consisted of chronic odontoid fracture in 17, Os odontoideum in 8, fresh odontoid fracture in 4, transverse ligament rupture in 1, rheumatoid arthritis in 1. Clinical features included neck pain in 31; restricted neck movement in 28, varying degrees of spastic quadriparesis in 19. All patients underwent posterior C(1) to C(2) pedicle screw fixation. Operative time, intraoperative blood loss, complications were recorded, neurological and radiographic studies were carried. RESULTS: Mean follow-up time was 13 months. Operative time averaged 2.5 h. Mean intraoperative blood loss was 300 ml. A patient had postoperative wound infection and was treated conservatively with antibiotics and local wound care. A patient developed pulmonary artery embolism and got well with anticoagulation. Satisfactory stability was achieved in all cases with no vascular and C(2) neuralgia. Average JOA score in 19 cases increased at final follow-up (P < 0.01). Solid fusion was achieved in 29 cases, fusion rate was 93.6%. CONCLUSIONS: Stabilization of atlantoaxial complex via pedicle screws of atlas and axis has advantages of intraoperative restoration, easier placement of screw, solid fixation. It is a safe and effective treatment modality for posterior C(1-2) fusion.

[Accuracy and related affecting factors of somatosensory evoked potential monitoring in cervical and thoracic surgery].

OBJECTIVE: To evaluate the accuracy and related affecting factors of the intra-operative somatosensory evoked potential monitoring in cervical and thoracic surgery. METHODS: Cortical somatosensory evoked potential (CSEP) monitoring and sub cortical somatosensory evoked potential (Sub-CSEP) monitoring were performed in cervical and thoracic surgery. Somatosensory evoked potential (SEP) changes were recorded during anaesthesia and operation and postoperative, which could be used to evaluate accuracy of SEP. RESULTS: Bilateral CSEP wave abnormalities were related to anaesthesia, decreasing wave amplitudes did not reach the alarming standard. Intra-operative manipulation to affect spinal cord would influence iso-lateral wave abnormality of CSEP and sub-CSEP, decreasing amplitudes reached the alarming standard. Local hypothermia such as cold water irrigating spinal cord would be to prolong the latent period. Low mean arterial pressure (MAP) mostly influenced amplitudes. Changes of SEP in local hypothermia and MAP did not reach the alarming standard. CONCLUSIONS: CSEP and Sub CSEP can reflex physiopathological condition of spinal cord, it is useful in evaluating spinal cord function and providing the safety for cervical and thoracic surgery.

Gene expression of collagen types IX and X in the lumbar disc.

OBJECTIVE: To study gene expression of collagen types IX and X in human lumbar intervertebral discs during aging and degeneration and to explore the role of collagen types IX and X in disc degeneration. METHODS: Fetal, adult and pathologic specimens were subjected to in situ hybridization with cDNA probes to investigate mRNA-expressions of types IX and X collagen gene. RESULTS: In fetal intervertebral discs, positive mRNA hybridization signals of type IX collagen were concentrated in the nucleus pulposus and the inner layer of anulus fibrosus. Interstitial matrix of the nucleus pulposus also showed positive type X collagen staining. Positive mRNA hybridization signals of types IX and X were not detected in the middle and outer layers of anulus fibrosus. In adult specimens, expression of type IX collagen mRNA was markedly decreased. No hybridization signals of type X collagen was observed. As for pathological specimens, there was no gene expression of type IX collagen. In severe degenerated discs from adults, there were focal positive expressions of type X collagen. CONCLUSIONS: Obvious changes of collagen gene expression occur with aging. Expression of type IX collagen decreases in adult and pathological discs. Results of type X collagen expression suggest that type X collagen is expressed only in older adult and senile discs (i.e., when disc degeneration has already reached a terminal stage), indicating the terminal stage of degeneration.