Severe traumatic dislocation of the lower cervical spine with mild neurological symptoms: Case reports and literature review.

CONTEXT: Severe traumatic fractures and dislocations of the lower cervical spine are usually accompanied by irreversible spinal cord injuries. Such patients rarely have mild or no neurological symptoms. FINDINGS: We report three cases of severe lower cervical dislocation without spinal cord injury and discuss the mechanisms underlying this type of injury. All three patients had severe lower cervical dislocation, but their neurological symptoms were mild. In all cases, the fractures occurred at the bilateral junctions of the lamina and pedicle, resulting in severe cervical spondylolisthesis, whereas the posterior structure remained in place, thereby increasing the cross-sectional area of the spinal canal. After preoperative skull traction for a few days, the patients underwent anterior or combined anterior and posterior cervical surgeries. All surgeries were successfully completed and the patient's symptoms disappeared at the last follow-up. CONCLUSION: Severe traumatic dislocation of the lower cervical spine with an intact neurological status is rare in clinical practice. Pathological canal enlargement preserves neurological function, and the most commonly injured segment is C7. Preoperative traction for closed reduction remains controversial. We suggest that if no obvious anterior compression is observed, closed reduction should be pursued. Anterior or combined anterior and posterior cervical surgeries can provide rigid fixation with satisfactory results.

Case report: A complete lower cervical fracture dislocation without permanent neurological impairment.

BACKGROUND: Complete fractures and dislocations of the lower cervical spine are usually associated with severe spinal cord injury. However, a very small number of patients do not have severe spinal cord injury symptoms, patients with normal muscle strength or only partial nerve root symptoms, known as "lucky fracture dislocation". The diagnosis and treatment of such patients is very difficult. Recently, we successfully treated one such patient. CASE PRESENTATION: A 73-year-old male patient had multiple neck and body aches after trauma, but there was sensory movement in his limbs. However, preoperative cervical radiographs showed no significant abnormalities, and computed tomography (CT) and magnetic resonance imaging (MRI) confirmed complete fracture and dislocation of C7. Before operation, the halo frame was fixed traction, but the reduction was not successful. Finally, the fracture reduction and internal fixation were successfully performed by surgery. The postoperative pain of the patient was significantly relieved, and the sensory movement of the limbs was the same as before. Two years after surgery, the patient's left little finger and ulnar forearm shallow sensation recovered, and the right flexion muscle strength basically returned to normal. CONCLUSION: This case suggests that when patients with trauma are encountered in the clinic, they should be carefully examined, and the presence of cervical fracture and dislocation should not be ignored because of the absence of neurological symptoms or mild symptoms. In addition, positioning during handling and surgery should be particularly avoided to increase the risk of paralysis.

Reduction of Lower Cervical Facet Dislocation: A Review of All Techniques.

OBJECTIVE: The surgical treatment of lower cervical facet dislocation is controversial. Great advancements on reduction techniques for lower cervical facet dislocation have been made in the past decades. However, there is no article reviewing all the reduction techniques yet. The aim is to review the evolution and advancements of the reduction techniques for lower cervical facet dislocation. METHODS: The application of all reduction techniques for lower cervical facet dislocation, including closed reduction, anterior-only, posterior-only, and combined approach reduction, is reviewed and discussed. Recent advancements on the novel techniques of reduction are also described. The principles of various techniques for reduction of cervical facet dislocation are described in detail. RESULTS: All reduction techniques are useful. The anterior-only surgical approach appears to be the most popular approach. Moreover, many novel or modified reduction and fixation methods have been introduced in recent years. CONCLUSION: The selection of surgical approach depends on a combination of factors, including surgeon preference, patient factors, injury morphology, and inherent advantages and disadvantages of any given approach.

Morphometric study and anatomical variation with its incidence of foramina transversaria on the lower cervical vertebrae / Estudio morfométrico y variación anatómica con la incidencia de forámenes transversos en las vértebras cervicales inferiores

SUMMARY: Anatomical variation of the foramina transversaria (FT) is associated with vertebral neurovascular symptoms and can cause complications after lower spine surgery, especially cervical pedicle screw (CPS) insertion. FT variation has been documented and classified in various populations, as this information can help increase cervical stability in subaxial vertebral surgery. Although the morphometry of the upper cervical spine in Thai populations has been reported, there have yet been no studies examining the features of FT. The FT of dried cervical spines (C3-C7; left and right side; n = 107, male = 53 and female = 54) were examined for morphological variation, and their anteroposterior (AP) and transverse (T) diameters were measured using a digital vernier caliper. Morphometric data and variations were compared by sex and lateral side. It was that the C3-C6 FT in both sexes were round, and the C7 FT was elliptical with an oblique right side. FT diameters did not differ significantly by sex except for the AP diameters of C6-C7 and for T diameters of C4 and C7. The left AP diameters of C3-C6 were significantly longer than the right, as were the T diameters of C4 and C7 FT. Additionally, T diameter was significantly longer than that of the AP, except that of the left C6 in male spines, which did not differ from the AP. Most FT examined were round. These findings should be considered in the provisional diagnosis of vertebral neurovascular symptoms caused by FT variation as well as that of neurovascular damage after cervical pedicle screw placement.

La variación anatómica del foramen transverso (FT) se asocia con síntomas neurovasculares vertebrales y puede causar complicaciones después de la cirugía de columna cervical inferior, especialmente la inserción de tornillos pediculares cervicales (TPC). La variación del FT se ha documentado y clasificado en varias poblaciones, ya que esta información puede ayudar a aumentar la estabilidad cervical en la cirugía vertebral subaxial. Aunque se ha informado sobre la morfometría de la columna cervical superior en poblaciones tailandesas, aún no se han realizado estudios que examinen las características de FT. Se examinó la variación morfológica del FT de vértebras cervicales secas (C3-C7; lado izquierdo y derecho; n = 107, hombres = 53 y mujeres = 54), y se midieron sus diámetros anteroposterior (AP) y transverso (T) usando un pie de metro digital. Se compararon datos morfométricos y variaciones por sexo y lado. Los FT de C3-a C6 en ambos sexos eran redondos, y el FT C7 era elíptico con el lado derecho oblicuo. Los diámetros del FT no difirieron significativamente por sexo excepto para los diámetros AP de C6- C7 y para los diámetros transversos de C4 y C7. Los diámetros AP izquierdos de C3-C6 eran significativamente más largos que los del lado derecho, al igual que los diámetros transversos de C4 y C7. Además, el diámetro transverso fue significativamente mayor que el AP, excepto el C6 izquierdo en las vértebras de hombres, que no difirió del AP. La mayoría de los FT examinados eran redondos. Estos hallazgos deben ser considerados en el diagnóstico provisional de síntomas neurovasculares vertebrales causados por la variación del FT, así como en el de daño neurovascular tras la colocación de tornillos pediculares cervicales.

Biomechanical effect of C5-C6 intervertebral disc degeneration on the human lower cervical spine (C3-C7): a finite element study.

The biomechanical effects of intervertebral discs and facet joints degeneration on the cervical spine are essential to understanding the mechanisms of spinal disorders to improve pathological and clinical treatment. In this study, the biomechanical effects of a progressively degenerated C5-C6 segment on the human lower cervical spine are determined by a detailed simulation of intervertebral disc degeneration. A detailed asymmetric three-dimension intact finite element model was developed using computed tomography scan data of the human lower cervical spine (C3-C7). The intact finite element model was then modified at the C5-C6 segment to build three degenerated models, such as mild, moderate, and severe degeneration. The physiological compressive load 73.6 N, and moment 1 Nm were applied at the superior endplate of the vertebra C3, and the inferior endplate of the C7 vertebra was a constraint for all degrees of freedom. Range of motion, maximum von Mises stress in the annulus, intradiscal pressure, and facet joint force of the degenerated models were computed. With progressive degeneration in the C5-C6 segment, the range of motion of degenerated and normal segments decreases in all postures. Intradiscal pressure of the degenerated segment decreases but increases in normal segments of degenerated segment C5-C6, and facet joint forces increase at both degenerated and normal segments. This study emphasizes that the degenerated disc alters the degenerated and normal segments' motion and loading patterns. The abnormal increase in facet joint force in the degenerated models threatened to accelerate the degeneration in the normal segments.

Surgical treatment was desirable to improve neuromuscular function in patients with sustained 3 years fracture-dislocation of lower cervical spine: A case report.

To investigate the changes in neuromuscular function of anterior approach combined with subtotal vertebral body resection and titanium mesh cage (TMC) internal fixation for the old fracture-dislocated lower cervical spine. A 56-year-old female was admitted to the hospital with neck pain and numbness of the left upper extremity for 3 years due to a fall injury from a height, which worsened for 20 days. Although 3 years had passed, the patient still had significant left limb numbness and decreased muscle strength. Eventually, the patient was diagnosed with the old fracture-dislocation type injury of C6 and C7. C6 was II-degree anterior dislocation and the bilateral joint process was locked, C7 was burst fracture, and C5 was spinal cord segment injury. Then, the operation of the anterior approach combined with subtotal vertebral body resection and TMC internal fixation was performed under general anesthesia. Postoperative symptoms were significantly improved. And during five-year of follow-up, no adverse reactions and complications were reported. Although cervical fracture and dislocation combined with cervical spinal cord injury had persisted for many years, surgical treatment was necessary. The anterior approach combined with subtotal vertebral body resection and TMC internal fixation was desirable to improve neuromuscular function for the old fracture-dislocation of the lower cervical spine, which has some guiding effects on the clinical treatment.

[Finite element analysis of the effect of plate placement angle on cervical spine stability in anterior cervical fusion surgery].

OBJECTIVE: Using the method of finite element analysis, to compare the biomechanical properties between the plate deviating from the long axis of the cervical spine and the standard placement of the plate in the anterior cervical fusion surgery. METHODS: A healthy female volunteer was selected and CT scan (C1-T1) was performed. Using Mimics 19.0, Geomagic Studio 2015, Solidworks 2018, Ansys Workbench 17.2 to establish a lower cervical spine (C3-C7) model and to verify the reliability of the model. Subsequently, anterior cervical plates of different angles and lengths were placed to establish an anterior cervical discectomy fusion (ACDF) model. Applying 73.6 N axial pressure and 1 NM pure moment on C3 to make the model produce flexion, extension, lateral bending and rotation activities, observed the model stress cloud diagram and recorded the maximum stress value of the instrument and the intervertebral mobility. RESULTS: The lower cervical spine (C3-C7) finite element model was established and verified against the published literature on the range of motion (ROM) of cervical spine. Effect of steel plate offset axis on stress distribution, maximum stress value and intervertebral ROM of internal fixation apparatus was minimal, and the mechanical effect of steel plate offset was less in double section steel plate than in single section steel plate. CONCLUSION: Little effect on the mechanical stability of the cervical spine was anticipated when the anterior cervical plate was not perfectly aligned with the long axis of the cervical spine. If the tilt of the plate in clinical surgery is less than 20°, there is no need to readjust the position of the plate.

Finite element analysis of the effect of plate placement angle on cervical spine stability in anterior cervical fusion surgery / 中国骨伤

OBJECTIVE@#Using the method of finite element analysis, to compare the biomechanical properties between the plate deviating from the long axis of the cervical spine and the standard placement of the plate in the anterior cervical fusion surgery.@*METHODS@#A healthy female volunteer was selected and CT scan (C@*RESULTS@#The lower cervical spine (C@*CONCLUSION@#Little effect on the mechanical stability of the cervical spine was anticipated when the anterior cervical plate was not perfectly aligned with the long axis of the cervical spine. If the tilt of the plate in clinical surgery is less than 20°, there is no need to readjust the position of the plate.

[Clinical application of cervical pedicle screw implantation technique under regional method].

OBJECTIVE: To investigate the effectiveness of cervical pedicle screw implantation technique under regional method. METHODS: The clinical data of 85 patients who met the selection criteria between April 2010 and May 2018 were retrospectively analyzed. There were 57 males and 28 females, aged 35-68 years, with an average of 57.6 years. Among them, there were 10 cases of ossification of posterior longitudinal ligament, 68 cases of cervical spondylosis with multilevel stenosis, 3 cases of cervical tumor, 1 case of congenital malformation, and 3 cases of cervical trauma; the lower cervical spine lesions involved C 3-C 7. Preoperative Frankel spinal cord injury grading: 2 cases of grade C, 51 cases of grade D, and 32 cases of grade E. Cervical pedicle screw implantation technique under regional method was performed with a total of 618 pedicle screws. Postoperative changes in neurological symptoms were observed; cervical mouth opening anteroposterior and lateral X-ray films and cervical CT examinations were performed to evaluate the pedicle screws position. RESULTS: The operation time was 2.5-4.0 hours, with an average of 3.0 hours. The intraoperative blood loss was 180-550 mL, with an average of 345 mL. No intraoperative vascular or nerve injury occurred. The patients with neurological symptoms were relieved to varying degrees. There were 2 cases of superficial incision infection after operation, the wound healed after enhanced dressing change. The postoperative hospital stay was 5-14 days, with an average of 8.4 days. At discharge, Frankel neurological grading was grade D in 26 patients and grade E in 59 patients. All the patients were followed up 6-24 months, with an average of 13 months. At last follow-up, cervical X-ray films showed the good pedicle screw fixation without loosening. Cervical CT evaluated the position of pedicle screws: 523 pedicle screws (84.7%) in grade Ⅰ, 80 (12.9%) in grade Ⅱ, and 15 (2.4%) in grade Ⅲ; the accuracy rate of the screw position was 97.6%. CONCLUSION: Cervical pedicle screw implantation technique under regional method can significantly improve the success rate of screw implantation. It is easy to operate, does not destroy the bone cortex, and has stable fixation.

Osteochondroma Arising from the Transverse Process of the Lower Cervical Spine in an Elderly Patient.

BACKGROUND: Osteochondroma rarely occurs in the lower cervical spine in elderly patients, because it usually develops during skeletal growth and because of the limited mobility and lower stress in the lower cervical spine. CASE DESCRIPTION: A 63-year-old man complained of 3-month history of neck pain and a hard, palpable mass in the lower cervical spine. Plain radiography, computed tomography (CT) scan, and magnetic resonance imaging (MRI) revealed a bony mass arising from the left C5 transverse process with a medullary continuation and calcification and soft tissue displacement at the C4-C6 level. After the operation, the biopsy finding was consistent with osteochondroma, without malignant degeneration. We performed en bloc resection of the tumor, including the cartilaginous cap. The patient's symptoms improved after resection of the osteochondroma and demonstrated no recurrence of tumor at a 1-year follow-up. CONCLUSIONS: This patient had a rare involvement of the transverse process without neurologic symptoms. Multiple imaging modalities, including plain radiography, CT, and MRI, play important roles in the diagnosis of osteochondroma. Complete surgical excision, including the cartilaginous cap, achieved a satisfactory surgical outcome and prevented possible recurrence.

Posterior Unlocking of Facet Joints Under Endoscopy Followed by Anterior Decompression, Reduction, and Fixation of Old Subaxial Cervical Facet Dislocations: A Technical Note.

OBJECTIVE: Besides the facet joints interlocking, the fibrous tissue or bony callus around the dislocated segments make the reduction for this kind of old injury to be more challenging and different from that of acute injuries. This study is aimed to present 4 cases of old subaxial cervical facet dislocations (SCFD) that were successfully treated with posterior unlocking under endoscopy followed by anterior decompression, reduction, and fixation. METHODS: Between January 2017 and December 2017, 4 patients with old SCFD who underwent posterior unlocking of facet joints under endoscopy followed by anterior decompression, reduction, and fixation were enrolled. A cervical collar was prescribed for 4 weeks postoperatively. Postoperative follow-up evaluations were conducted at 2, 6, and 12 months, including neck visual analogue scale score and neck disability index, radiography, and computed tomography. RESULTS: The operative time averaged 145 minutes (range, 130-155 minutes). No deterioration of neural function, major vessel rupture, or iatrogenic injury to esophagus occurred. Intraoperative blood loss averaged 45 mL (range, 40-50 mL). Hospital stay for all patients was only 4 days. The neck visual analogue scale score and neck disability index were improved at the final follow-up, and interbody fusion was satisfactory without any radiologic sign of instability or internal failure. CONCLUSIONS: For patients with old SCFD, the unlocking of facet joints via the posterior approach under endoscopy followed by anterior decompression, reduction, and fixation is an alternative technique.

Biomechanical analysis on of anterior transpedicular screw-fixation after two-level cervical corpectomy using finite element method.

BACKGROUND: Anterior cervical trans-pedicle screw fixation was introduced to overcome some of the disadvantages associated with anterior cervical corpectomy and fusion. In vitro biomechanical studies on the trans-pedicle screw fixation have shown excellent pull-out strength and favorable stability. Comprehensive biomechanical performance studies on the trans-pedicle screw fixation, however, are lacking. METHODS: The control computed tomography images (C2-T2) were obtained from a 22-year-old male volunteer. A three dimensional computational model of lower cervical spine (C3-T1) was developed using computed tomography scans from a 22 year old human subject. The models of intact C3-T1 (intact group), anterior cervical trans-pedicle screw fixation (trans-pedicle group), and anterior cervical corpectomy and fusion (traditional group) were analyzed with using a finite element software. A moment of 1 N·m and a compressive load of 73.6 N were loaded on the upper surface and upper facet joint surfaces of C3. Under six conditions, four parameters such as the range of motion, titanium mesh plant stress, end-plate stress, and bone-screw stress were measured and compared on two treatment groups. FINDINGS: Compared with the intact model, the range of motions for treatment groups were decreased. Compared with cervical corpectomy and fusion, the titanium plant, C4 upper end-plate and C7 lower end-plate stresses in trans-pedicle group were reduced. No significant difference was discovered on bone-screw stress between the two groups for lateral flexion and rotation, but bone-screw stress is smaller in trans-pedicle group when compared with traditional group. With exception of individual difference, trans-pedicle group had better biomechanical results than traditional group in range of motions, titanium mesh plant stress, end-plate stress and bone-screw stress. INTERPRETATION: The trans-pedicle method has better biomechanical properties than the anterior cervical corpectomy and fusion making it a viable alternative for cervical fixations.

Treatment of Injuries to the Subaxial Cervical Spine: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

STUDY DESIGN: Expert consensus. OBJECTIVES: To establish treatment recommendations for subaxial cervical spine injuries based on current literature and the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma. METHODS: This recommendation summarizes the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma. RESULTS: Therapeutic goals are a stable, painless cervical spine and protection against secondary neurologic damage while retaining maximum possible motion and spinal profile. The AOSpine classification for subaxial cervical injuries is recommended. The Canadian C-Spine Rule is recommended to decide on the need for imaging. Computed tomography is the favoured modality. Conventional x-ray is preserved for cases lacking a "dangerous mechanism of injury." Magnetic resonance imaging is recommended in case of unexplained neurologic deficit, prior to closed reduction and to exclude disco-ligamentous injuries. Computed tomography angiography is recommended in high-grade facet joint injuries or in the presence of vertebra-basilar symptoms. A0-, A1- and A2-injuries are treated conservatively, but have to be monitored for progressive kyphosis. A3 injuries are operated in the majority of cases. A4- and B- and C-type injuries are treated surgically. Most injuries can be treated with anterior plate stabilization and interbody support; A4 fractures need vertebral body replacement. In certain cases, additive or pure posterior instrumentation is needed. Usually, lateral mass screws suffice. A navigation system is advised for pedicle screws from C3 to C6. CONCLUSIONS: These recommendations provide a framework for the treatment of subaxial cervical spine Injuries. They give advice about diagnostic measures and the therapeutic strategy.

Immediate reduction under general anesthesia and combined anterior and posterior fusion in the treatment of distraction-flexion injury in the lower cervical spine.

BACKGROUND: Distraction-flexion of the lower cervical spine is a severe traumatic lesion, frequently resulting in paralysis. The optimal surgical treatment is controversial. It has been a challenge for orthopedic surgeons to manage distraction-flexion injury in the lower cervical spine while avoiding the risk of iatrogenic damage. Thus, safer strategies need to be designed and adopted.This study aimed to evaluate the clinical efficacy of immediate reduction under general anesthesia and combined anterior and posterior fusion in the treatment of distraction-flexion injury in the lower cervical spine. METHODS: Twenty-four subjects of traumatic lower cervical spinal distraction-flexion were retrospectively analyzed from January 2010 to December 2013. Traffic accident was the primary cause of injury, with patients presenting with dislocated segments in C4-5 (n = 8), C5-6 (n = 10), and C6-7 (n = 6). Sixteen patients had unilateral facet dislocation and eight had bilateral facet dislocation. Spinal injuries were classified according to the American Spinal Injury Association (ASIA) impairment scale (2000 edition amended), with four cases of grade A, four cases of grade B, ten cases of grade C, four cases of grade D, and two cases of grade E. On admission, all patients underwent immediate reduction under general anesthesia and combined anterior and posterior fusion. The mean follow-up time was 3.5 years. RESULTS: All operations were completed successfully, with no major complications. Postoperative X-rays showed satisfactory height for the cervical intervertebral space and recovery of the vertebral sequence. Bone fusion was completed within 4 to 6 months after surgery. Surgery also significantly improved neurological function in all patients. CONCLUSION: Immediate reduction under general anesthesia and combined anterior and posterior fusion can be used to successfully treat distraction-flexion injury in the lower cervical spine, obtaining completed decompression, safe spinal re-alignment, and excellent immediate postoperative stability.

Influences of different lower cervical bone graft heights on the size of the intervertebral foramen: multiple planar dynamic measurements with laser scanning.

The aim of this study is to evaluate the influences of different bone graft heights on the size of the intervertebral foramen, which will help determine the optimal graft height in clinical practice. Six fresh adult cadavers were used, with the C5-C6 vertebral column segment defined as the functional spinal unit (FSU). After discectomy, the C5/6 intervertebral height was set as the baseline height (normal disc height). We initially used spiral computed tomography (CT) to scan and measure the middle area of the intervertebral foramen when at the baseline height. Data regarding the spatial relationship of C5-C6 were subsequently collected with a laser scanner. Grafting with four different sized grafts, namely, grafts of 100, 130, 160, and 190% of the baseline height, was implanted. Moreover, we scanned to display the FSU in the four different states using Geomagic8.0 studio software. Multiple planar dynamic measurements (MPDM) were adopted to measure the intervertebral foramen volume, middle area, and areas of internal and external opening. MPDM with a laser scanner precisely measured the middle area of the intervertebral foramen as spiral CT, and it is easy to simulate the different grafts implanted. With the increase of the bone graft height, the size of the intervertebral foramen began to decrease after it increased to a certain point, when grafts of 160% of the baseline height implanted. MPDM of the intervertebral foramens with laser scanning three-dimensional (3D) reconstitution are relatively objective and accurate. The recommended optimal graft height of cervical spondylosis is 160% of the mean height of adjacent normal intervertebral spaces.

Stability of two anterior fixations for three-column injury in the lower cervical spine: biomechanical evaluation of anterior pedicle screw-plate fixation.

Objectives This study aimed to evaluate the stability of anterior pedicle screw-plate (APSP) fixation and anterior vertebral body screw-plate (AVBSP) fixation for three-column injury in the lower cervical spine. Methods Six fresh-frozen human cadaveric specimens of the lower cervical spine were prepared. After measurement of the range of motion (ROM) in the intact state, the specimens were prepared as three-column injury models. The models were stabilized by AVBSP or APSP fixation. The ROM of the models in the two states was measured. The ROM in the two states was compared. Results The ROM of the intact state in all directions was significantly smaller than that of the AVBSP state and significantly larger than that of the APSP state. The ROM of the AVBSP state in all directions was significantly larger than that of the APSP state. Conclusions This study shows that APSP fixation can provide sufficient stability for three-column injury in the lower cervical spine. The primary stability of our models using APSP fixation is superior to that of AVBSP fixation. These results suggest that APSP can be used for three-column injury in the lower cervical spine.

New reduction technique for the treatment of unilateral locked facet joints of the lower cervical spine : A retrospective analysis of 12 cases.

BACKGROUND: Closed reduction of bilateral locked facet joints of the lower cervical spine is possible, but reduction of unilateral locked facet joints of the lower cervical spine (ULFJLCS) is challenging. We explored a new, simple, safe, and effective closed reduction method for the treatment of ULFJLCS. METHODS: A retrospective analysis was done on 12 consecutive cases with traumatic ULFJLCS that underwent closed reduction by Z­shape elevating-pulling reduction through a halo-vest. After reduction, only anterior cervical decompression and internal fixation were performed. The success of reduction and nerve function was assessed, and follow-up data analyzed. RESULTS: All patients using our new reduction technique underwent successful closed reduction; the shortest time of reduction was 40 min and the longest 110 (mean, 65) min. No aggravation of neurological damage was observed, nor were other complications. All patients were followed-up from 28 to 72 (mean, 44) months after surgery. The improvement in Frankel's score (on average) was two levels in most patients. CONCLUSION: These data demonstrate that our new reduction technique is a simple, safe, and effective treatment for ULFJLCS.

Imaging measurement of circumferential cortical thickness of anterior entrance and anterior half of lower cervical pedicles and its application analysis / 第二军医大学学报

Objective To measure the circumferential cortical thickness of anterior entrance and anterior half of lower cervical pedicles on computed tomography (CT) images, providing a reference for accurate anterior cervical pedicle screws. Methods CT scanning was performed in 10 normal lower cervical vertebrae from fresh cadavers, and the coronal and sagittal reconstructed images were obtained. The images were then opened in AutoCAD-2007 software to perform quantitative measurement (accuracy was 0. 1 mm) using the “dimaligned function” of dimension menu, and measurement parameters included the thicknesses of superior, medial, inferior and lateral cortex of anterior entrance of pedicle (SAE. MAE. IAE and LAE. respectively), and thicknesses of superior, medial, inferior and lateral cortex of anterior half of pedicle (SPA, MPA, IPA and LPA, respectively). Results Average thicknesses of SAE. MAE. IAE. LAE, SPA, MPA. IPA, and LPA at left and right side from Q to C7 were (1. 9 + 0. 6) and (1. 9 + 0. 5) mm, (1. 9 + 0. 7) and (1.9+0. 4) mm. (2.4 + 0. 6) and (2. 4 + 0. 5) mm, (0. 9 + 0. 5) and (0. 9 + 0. 6) mm, (2. 3 + 0. 9) and (2. 3 +0. 7) mm, (2. 1 + 0. 5) and (2. 1 + 0. 6) mm, (2. 2+0. 8) and (2. 2+0. 7) mm, and (1. 0 + 0. 7) and (1. 0 + 0. 6) mm, respectively. There was no significant difference in same measurement parameter between left and right sides at same cervical level (P>0. 05). Single factor random block analysis of variance found LAE and LPA were significantly thinner than the other 6 parameters of the same side of same cervical vertebra (all P0. 05). Conclusion LAE and LPA are the thinnest among the 8 measurement parameters from C3 to C7, which suggests LAE and LPA have the weakest resistance to exotic force if resistance strength to exotic force is parallel to cortex thickness. We should avoid locating close to LAE when finding anterior entrance or close to LPA when inserting anterior cervical pedicle screws.

Finite element analysis on lower cervical spine by anterior cervical corpectomy and fusion sugery / 医用生物力学

Objective To establish the three-dimensional finite element model of human lower cervical spine C3-7 motion segments after anterior cervical corpectomy and fusion (ACCF) surgery with titanium mesh and bone graft,and to analyze the stability of cervical spine and stress distribution of internal fixation devices after ACCF surgery.Methods The finite element model of cervical spine C3-7 segments after ACCF of C5 segment with titanium mesh,bone graft,plate and screw fixation was established,and C3-7 segment intact model of cervical vertebra was also constructed.The torque moment of 0.5,1.0,1.5,2.0 N · m was applied to the ACCF surgery model.The ROM,maximum stress in facet joint and stress distributions on internal fixation devices under flexion,extension,lateral bending and axial rotation movement were analyzed.Results ROM of reconstructed C5 segment increased with the torque moment increasing after ACCF surgery.In the case of 1.0 N · m tomue moment and 50 N preload,the ROM of reconstructed C5,C3-4,C6-7 and C3-7 segment was reduced by 81％,62％,58％ and 80％ compared with the intact model.The maximum stress in facet joint of reconstructed C5 segment reduced and the stress in adjacent segments significantly increased.The stress of titanium mesh was mainly distributed on the compression side of movement,and high stress was located in the roots of screws.Conclusions ACCF surgery can promote the stability of cewical spine,decrease the stress in facet joint of operation segment,and has better treatment effect on easing compression from spinal cord caused by cervical spondylotic myelopathy.The research results will provide some theoretical basis for clinical application of ACCF surgery.