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Objective To establish the finite element model of upper cervical vertebrae C0-3 with Jefferson fracture, and to analyze the influence of posterior atlantoaxial fusion (PSF) and occipitocervical fusion (OCF) on biomechanical properties of the vertebral body and mechanical conduction of the screw-rod system. Methods Based on CT images, the C0-3 segment Jefferson fracture model of human upper cervical spine was established. PSF, OCF1 and OCF2 internal fixation were performed according to surgical plan in clinic, and 50 N concentrated force and 1.5 N·m torque were applied to bottom of the occipital bone. The stress distribution and range of motion (ROM) of the cervical vertebral body, the maximum stress of the screw-rod system and the stress distribution of the intervertebral disc for C0-3 segment during flexion, extension, bending and rotation of the upper cervical spine were studied. Results Compared with PSF, the ROM of OCF1 and OCF2 vertebral bodies increased, and the stress of the nail rod decreased. OCF had a better fixation effect. Conclusions PSF, OCF1 and OCF2 fixation method can reduce the upper cervical ROM and restore stability of the upper cervical spine, which make stress distributions of the vertebral body and intervertebral disc tend to be at normal level. The research result can provide a theoretical basis for clinical surgery plan.
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Objective To explore the differences and correlation of imaging parameters of occipital-C2 angle (OC2A) and posterior occipitocervical angle (POCA) between sex and age, so as to provide theoretical reference for fixing the position of head and neck in occipitocervical fusion. Methods The imaging data of 473 cases (339 males and 134 females) were collected and divided into 2 groups according to sex. Each group was subdivided into 6 groups according to age: ≤29 year-old, 30-39 year-old, 40-49 year-old, 50-59 year-old, 60-69 year-old and ≥70 year-old. OC2A and POCA were measured in Mimics software, and their differences with sex and age were statistically analyzed. Results There was no significant difference in OC2A and POCA between sexes (P0.05); There were significant differences in POCA between the male group of 30-39 year-old and ≤29 year-old (P<0.05), but between the group of 40-49 year-old and each group (P<0.05). In the female group, there was significant difference between the group of ≤29 year-old and all age groups (P<0.05), but there was no significant difference among the other groups (P<0.05). Pearson correlation analysis showed that there was a positive correlation between OC2A and POCA (r= 0.038, P<0.05), that is, there was no correlation between them. Conclusion There is no difference in OC2A and POCA values between sexes; there are differences in OC2A and POCA values in males among different age groups, suggesting that clinical attention should be paid to the age differences in males, while there is no difference in OC2A values in females, but POCA is different in different age groups. The changes of OC2A and POCA values in different age groups and sex provide a parameter basis for fixing the anatomical reduction angle of head and neck in occipitocervical fusion.
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BACKGROUND: For patients with basilar invagination under occipitocervical fusion, the unreasonable choice of fixed angle in the occipitocervical region will reduce the clinical efficacy and accelerate the degeneration of subaxial cervical spine OBJECTIVE: To measure the Occipito-C2 angle (OC2A) and the posterior occipitocervical angle (POCA) in healthy subjects, and to analyze the influence of OC2A and POCA selection on the clinical efficacy and the loss of cervical spinal angle (CSA) of subaxial cervical spine in the occipitocervical fusion of basilar invagination. METHODS: 150 healthy subjects (healthy group) were grouped by gender and age, with 75 males and 75 females divided into five age groups ranging from 20 to 69 years old. OC2A and POCA of each healthy subject were measured by three spine surgeons. The intraclass correlation coefficient analysis was performed on the two parameters to prove their consistency. The mean of the two parameters and 95% confidence interval (95% CI) were obtained. Clinical data from 42 patients (malformation group) with basilar invagination who underwent occipitocervical fusion from January 2012 to January 2017 were analyzed retrospectively. These patients were divided into ideal angle subgroup and non-ideal angle subgroup, according to whether their OC2A and POCA immediately after postoperative ambulation were at 95% CI of the healthy group or not. OC2A, POCA, and CSA angles were measured preoperatively, immediately after postoperative ambulation, and at the final follow-up visit. The preoperative and final follow-up visual analog scale (VAS) score, Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and the loss of CSA from immediately after postoperative ambulation to the final follow-up (dCSA) were recorded. RESULTS AND CONCLUSION: The values of OC2A and POCA were (14.5±3.7)° and (108.2±8.1)° in the healthy group, respectively, and the respective 95% CI values were 7.2° -21.8° and 92.3° -124.0° as the normal range. There was a negative correlation between OC2A and POCA (r=-0.386, P < 0.001). The preoperative value of OC2A [(5.6±4.3)°] in the malformation group was smaller than that in the healthy group (P < 0.001); however, the preoperative values of POCA [(123.9±10.4)°] and CSA [(25.7±9.5)°] in the malformation group were larger than those in the healthy group (P < 0.001). In the 42 basilar invagination patients, 26 patients (ideal angle subgroup) were fixed in the ideal angle range immediately after postoperative ambulation (95% CI of the healthy group); 16 patients (non-ideal angle subgroup) were not fixed in the 95% CI of the healthy group, of which 14 patients (87.5%) had OC=A lower than 7.2° (lower limit of 95% CI of the healthy group), and 2 patients (12.5%) had POCA higher than 124.0° (upper limit of 95% CI in healthy group). The VAS score, JOA score and NDI of patients in the two subgroups were significantly improved compared with those before operation (P < 0.05). The VAS score and NDI of the ideal angle subgroup were higher than those of the non-ideal angle subgroup, but JOA score was lower than that of the non-ideal angle subgroup (P < 0.05). At the same time, dCSA [(4.0±6.8)°] in the ideal angle subgroup was significantly higher than that in the non-ideal angle subgroup [(-1.6±3.9)°; P < 0.05]. To conclude, the biomechanical balance between the occipitocervical region and subaxial cervical spine in patients with basilar invagination is different from that of normal healthy people. Therefore, it is not recommended to force OC2A and POCA to be fixed in the normal reference range during occipitocervical fusion for basilar invagination. Fixation of OC2A and POCA in the normal reference range will reduce the clinical efficacy of patients and accelerate the dCSA.
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Introduction: There are various diseases and anomalies in humans which require occipitocervical fusion using medial orlateral occipital screw placement along with rod or plate placement.[1] There are many ongoing arguments regarding the safearea for screw placement on the occiput during fusion techniques. Morphological analysis of occipital bone thickness providesconfidence in placing screws. Here, we try mapping occipital bone using computed tomography (CT) which would benefit forsafe fusion in population of southern Tamil Nadu.Materials and Methods: We randomly selected the CT scans of 50 patients in the age group of 20–60 years, and occipitalbone thickness mapping is done and tabulated and compared with the previous studies from different demographical areas.Results: The maximum thickness of the occipital bone was at the level of the external occipital protuberance (EOP) at 16.2 mm.Areas with thicknesses >8 mm were more frequent at the EOP and up to 2 cm in all directions, as well as up to 1 cm in alldirections at a height of 1 cm inferiorly, and up to 3 cm from the EOP inferiorly in males and it’s up to 2 cm in females. Themale group tended to have a thicker occipital bone than the female group, and the differences were significant around the EOP.Based on these data, there are 10 safe points for males which include: M0, M1, M2, M3, L1, L2, R1, R2 at level 0, L1, and R2at level 1 and 9 safe points for female which include all the above except M3.Conclusion: There is variability in the thickness of occipital bone in adult people from different demographic areas andthere is also a significant difference between male and female patients. Hence, this study helps in pre-operative planning inoccipitocervical fusion in people of this region.
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Objective: To study the application of occipitocervical fusion and fixation in malformation of craniocervical junction surgery. Methods: Thirty-six consecutive patients with craniocervical junction malformation were decompressed under evoked-potential monitoring. Sixteen patients were treated with posterior occipitocervical fusion and fixation using Vertex screw-hook system, and 11 using Vertex screw-rod system, other patients using Mountaineer OCT spinal system. All patients were followed up for 2 to 12 years (mean 7 years). The recovery rate was analysed based on the scoring system of the Japanese Orthopaedic Association (JOA). Results: All the patients were followed up. A stable bony fusion according to radiological criteria was achieved in all cases. There was no implant broken and dislocation. The improvement rate according to JOA scoring system were evaluated. Twenty-four cases (66.7%) got cured; 4 cases (11.1%) had remarkable effects; 8 cases (22.2%) were effective; none was ineffective. Conclusion: Occipitocervical stabilizations hope to be restored through occipitocervical fusion and fixation. Good results can be obtained in most patients with complete radiological data, proper surgery indication, suitable surgical modality and internal fixation materials.
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Objective·To study the application of occipitocervical fusion and fixation in malformation of craniocervical junction surgery.Methods·Thirty-six consecutive patients with craniocervical junction malformation were decompressed under evoked-potential monitoring.Sixteen patients were treated with posterior occipitocervical fusion and fixation using Vertex screw-hook system,and 11 using Vertex screw-rod system,other patients using Mountaineer OCT spinal system.All patients were followed up for 2 to 12 years (mean 7 years).The recovery rate was analysed based on the scoring system of the Japanese Orthopaedic Association (JOA).Results·All the patients were followed up.A stable bony fusion according to radiological criteria was achieved in all cases.There was no implant broken and dislocation.The improvement rate according to JOA scoring system were evaluated.Twenty-four cases (66.7％) got cured;4 cases (11.1％) had remarkable effects;8 cases (22.2％) were effective;none was ineffective.Conclusion·Occipitocervical stabilizations hope to be restored through occipitocervical fusion and fixation.Good results can be obtained in most patients with complete radiological data,proper surgery indication,suitable surgical modality and internal fixation materials.
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Objective To study the application of cervical vertebral artery CT angiography(CTA) preoperatively in the screw setting of upper cervical spine.Methods The data of 170 patients who underwent upper cervical spine surgery from January 2014 to December 2015 in our hospital were retrospectively analyzed,of whom 80 cases with typeⅡodontoid fractures,90 cases with atlantoaxial dislocation;20 cases were operated with occipitocervical fusion,150 cases treated with atlantoaxial fusion.Seventy-eight cases were examinated by cervical vertebral artery CTA before sugery(observation group) but the other 92 cases(control group).The rate of the vertebral arterial lesion between the two groups were compared.Results Six cases with vertebral artery injury in control group,the incidence of arterial injury was 7％;unilateral vertebral artery was found in 3 cases,small congenital development of left cervical vertebral artery in 5 case,abnormal branch in 5 cases.The rate of dysplasia was 17％,and the rate of vertebral artery injury was 0.The rate of vertebral artery injury in control group was higher than observation group,the difference was significant(P<0.05).Conclusion Vertebral artery CTA examination preoperatively may become a routine examination,in order to make the operator carefully evaluate the relationship between the vertebral artery with atlantoaxial vertebral,choose the accurate screw-setting and avoid the vertebral artery injury in the upper cervical spine surgery.
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STUDY DESIGN: A retrospective computed tomography (CT)-based morphometric study of 82 occipital condyles in the Indian population, focusing on critical morphometric dimensions with relation to placing condylar screws. PURPOSE: This study focused on determining the feasibility of placing occipital condylar screws in an Indian population using CT anatomical morphometric data. OVERVIEW OF LITERATURE: The occipital condylar screw is a novel technique being explored as one of the options in occipitocervical stabilization. Sex and ethnic variations in anatomical structures may restrict the feasibility of this technique in some populations. To the best of our knowledge, there are no CT-based data on an Indian population that assess the feasibility of occipital condylar screws. METHODS: We measured the dimensions of 82 occipital condyles in 41 adults on coronal, sagittal, and axial reconstructed CT images. The differences were noted between the right and left sides and also between males and females. Statistical analysis was performed using the t-test, with a p-value of < 0.05 considered significant. RESULTS: Mean sagittal length and height were 17.2±1.7 mm and 9.1±1.5 mm, respectively. Mean condylar angle/screw angle was 38.0°±5.5° from midline, with mean condylar length and width of 19.6±2.6 mm and 9.5±1.0 mm, respectively. Average coronal height on the anterior and posterior hypoglossal canal was 10.8±1.4 mm and 9.0±1.4 mm, respectively. The values in females were significantly lower than those in males, except for screw angle and condylar width. Based on Lin et al.'s proposed criteria, eight of 82 condyles were not suitable for condylar screws. CONCLUSIONS: Preliminary CT morphometry data of the occipital condyle shows that condylar screws are anatomically feasible in a large portion of the Indian population. However, because a small number of population may not be suitable for this technique, meticulous study of preoperative anatomy using detailed CT data is advised.
الموضوعات
Adult , Female , Humans , Male , Retrospective Studiesالملخص
Dyspnea or dysphagia after occipitocervical fusion is well-known complications. It could be occurred when occipitocervical fusion is performed with the neck flexion position which leads to the narrowing of the airway and retropharyngeal space. However, we experienced a case of dyspnea and dysphagia after posterior C1-C2 fusion. A 68-year-old male showed no evidence of occipitocervical instability in preoperative studies. He complained of progressive dyspnea and dysphagia after C1-2 fusion and follow-up computed tomography (CT) and magnetic resonance (MRI) showed relatively narrow spinal canal at the level of C1-2 compared to preoperative studies and serial plain radiographic studies decreased occipitocervical (O-C2) angle gradually. Despite of conservative treatment, his symptom was not improved. So we did C1 posterior arch decompression and extended fusion to the occiput with neck extension position. Dyspnea and dysphagia gradually improved after the surgery and complete recovery was observed within a month. Though we did not know the causes of dyspnea and dysphagia exactly, two mechanisms were possible one was cord irritation due to anterior migration of C1 posterior arch after C1-2 fusion. The other was alar ligament disruption with microinstability between the occiput and atlas. We present the case of dyspnea and dysphagia after posterior C1-2 fusion.
الموضوعات
Aged , Humans , Male , Decompression , Deglutition Disorders , Dyspnea , Follow-Up Studies , Ligaments , Magnetic Resonance Spectroscopy , Neck , Spinal Canal , Succinatesالملخص
OBJECTIVE: Craniovertebral junction (CVJ) consists of the occipital bone that surrounds the foramen magnum, the atlas and the axis vertebrae. The mortality and morbidity is high for irreducible CVJ lesion with cervico-medullary compression. In a clinical retrospective study, the authors reviewed clinical and radiographic results of occipitocervical fusion using a various methods in 32 patients with CVJ instability. METHODS: Thirty-two CVJ lesions (18 male and 14 female) were treated in our department for 12 years. Instability resulted from trauma (14 cases), rheumatoid arthritis (8 cases), assimilation of atlas (4 cases), tumor (2 cases), basilar invagination (2 cases) and miscellaneous (2 cases). Thirty-two patients were internally fixed with 7 anterior and posterior decompression with occipitocervical fusion, 15 posterior decompression and occipitocervical fusion with wire-rod, 5 C1-2 transarticular screw fixation, and 5 C1 lateral mass-C2 transpedicular screw. Outcome (mean follow-up period, 38 months) was based on clinical and radiographic review. The clinical outcome was assessed by Japanese Orthopedic Association (JOA) score. RESULTS: Nine neurologically intact patients remained same after surgery. Among 23 patients with cervical myelopathy, clinical improvement was noted in 18 cases (78.3%). One patient died 2 months after the surgery because of pneumonia and sepsis. Fusion was achieved in 27 patients (93%) at last follow-up. No patient developed evidence of new, recurrent, or progressive instability. CONCLUSION: The authors conclude that early occipitocervical fusion to be recommended in case of reducible CVJ lesion and the appropriate decompression and occipitocervical fusion are recommended in case of irreducible craniovertebral junction lesion.
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Humans , Male , Arthritis, Rheumatoid , Asian People , Axis, Cervical Vertebra , Decompression , Follow-Up Studies , Foramen Magnum , Occipital Bone , Orthopedics , Pneumonia , Retrospective Studies , Sepsis , Spinal Cord Diseases , Spineالملخص
Occipitocervical posterior fusion itself is an uncommon cause of severe dysphagia. But occipitocervical malalignment after posterior fusion can be a cause of severe dysphagia. A 46-year-old man was referred to the department of rehabilitation medicine because of swallowing difficulty. He complained of severe dysphagia immediately after the occipitocervical posterior fusion. From the lateral view of video-fluoroscopic swallowing study (VFSS), we could conclude that the mechanical cricopharyngeal relaxation failure was a direct cause of his dysphagia and this was due to malalignment of the occipitocervical fixation. His occipitoaxial angle was fixed in hyperflexed position and this lead to the severe dysphagia and even dyspnea. After the revision operation, his dysphagia and dyspnea symptom was dramatically resolved. The occipitoaxial angle can be a useful index, which measure the anatomic relation of the occiput and the cervical vertebrae on sagittal plane, on evaluation of the swallowing function in the patient who had occipitocervical posterior fusion.
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Female , Humans , Middle Aged , Cervical Vertebrae , Deglutition , Deglutition Disorders , Dyspnea , Relaxationالملخص
STUDY DESIGN: The results of posterior occipitocervical fusions were analyzed retrospectively based on the results of post-operative radiographs. OBJECTIVES: To investigate subjective methods for the evaluation of occipitocervical stabilization by posterior fusion. SUMMARY OF LITERATURE REVIEW: Few studies have been performed that describe the methods utilized for the evaluation of the union of the instrumented segments. MATERIALS AND METHODS: Occipitocervical fusions were performed in 16 patients from 1995 to 2004. The patients underwent occipitocervical fusions with autogenous iliac bone grafting and wire fixation (5), loop and sublaminar wire fixation (3), C-D occipitocervical rod (2), and contoured reconstruction plate (6). The stability and failure of the instrumentation in the fusion sites were evaluated with flexion/extension lateral radiographs. The stability was evaluated by a change in the degrees and distances between the occiput and cervical vertebrae. RESULTS: Two of five patients who had undergone wire fixation with autogenous bone grafting were considered to have a nonunion because of persistent segmental instability: greater than 2 degrees and 2 mm three months postoperatively. In the other patients, we were unable to determine the presence of a solid fusion mass at the fusion site, because of overlapping of the instrumentation devices and graft bones. However, since there was no definite motion that indicated segmental instability and instrumentation breakage or loosening on flexion and extension radiographs, we considered these as stable fixations. CONCLUSION: It was difficult to evaluate whether or not the grafts were incorporated into the recipient sites, due to the complexity of the occipitocervical junction and the overlapping of the instrumentation. After removal of the external immobilization 3 months postoperatively, although flexion/extension radiographs taken 6 months postoperatively, demonstrated no motion at the fusion site, the occipitocervical fusions were judged to be stabilized rather than fused.
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Female , Humans , Bone Transplantation , Cervical Vertebrae , Immobilization , Retrospective Studies , Transplantsالملخص
[Objective]To evaluate the effects of transpedicular internal fixation system for occipitocervical fusion.[Method]From Jan.2004 to Jan.2007,occipitocervical fusion was performed in 21 patients(12 male,9 female,mean age 45.3 years) with transpedicular internal fixation system(Sofamor Danek Company).There were 14 with upper cervical tumor,3 with cervical congenital malformation and 4 with dens axis fracture combined with atlantoaxial dislocation.The clinical outcomes were investigated by clinical observations,radiologic studies and statistical analysis.[Result]All the patients were followed up for 6 to 40 months with an average of 21 months.The result of X-ray showed that bony fusion was successful in 16 patients at 3 months and 5 patients at 6 months of follow-ups.There was no deterioration of spinal cord injury.The JOA scores of neurofunction increased from 5-17 points(mean 12.6 points) to 8-17 points(mean 15.8 points),with the improvement of 72%.All patients were partly limited in rotation movement.Seventeen patients had a rotatain of 100?,three was 80?,and one was 50?.[Conclusion]Transpedicular internal fixation system has multiaxial screw of three-column fixation and plastic rods,which offers strong fixation and good fusion.It can also benefit the maintenance of cervical curve.It is an effective and reliable method for reconstruction of upper cervical stability.
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[Objective]To provide the mechanical evidence of self manufactured metallic-rectangular frame on the reconstruction of the stability of occipitocervical junction.[Method]Seven of the adult cervical spinal specimens which were entire wet-cadavers(from occipitale to C_6) were made to simulate the C_(0～2) fracture dislocation.These of specimens dislocated were fixed by metallic-rectangular frame and Occipito-cervical plate respectively.The three dimensional movements of C_(0～2) were recorded through photogrametry with a pure moment of 1.53 Nm.The range of motion(ROM) of each specimens in two fixation was caculated.[Result]Loaded by 1.53Nm,In metallic-rectangular frame fixation,the ROM in flexion,extension,lateral bending and axial rotation were 5.9?、7.7?、5.6?、11.2? respectively,decreased by 157.6%、68.8%、58.9%、131.3%,compared with occipitocervical plate fixation group.[Conclusion]Metallic-retangular frame fixation can reconstruct the stability of Occipitocervical junction immediatey,and is a relativity effective internal fixation for occipitocervical fusion.
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Klippel-Feil syndrome is characterized by congenital fusion of cervical vertebrae with a wide range of associated anomaly. The authors present a 50-year-old Klippel-Feil syndrome patient with a minor trauma followed progressive quadriparesis. He had typical radiologic findings of type II Klippel-Feil syndrome and presented progressive myelopathy due to cord compression at foramen magnum level with cervical instability. The patient underwent craniocervical decompression and fusion. The authors reviewed the pertinent literatures and discussed this rare syndrome.
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Female , Humans , Middle Aged , Cervical Vertebrae , Decompression , Foramen Magnum , Klippel-Feil Syndrome , Quadriplegia , Spinal Cord Diseasesالملخص
Atlantoaxial dislocation is common in patients with Down syndrome, and an increased incidence was first noted by Tishler and Martel in 1965. Laxity of the transverse atlantal ligament is thought to be responsible for atlantoaxial dislocation, and surgical stabilization has been recommended for pateints who have instability, with or without myelopathy. Various surgical techniques and hardwares have been developed for occipitcervical fusion with varying degrees of results. The authors presents a case of Down syndrome with cervical myelopathy treated by occipitocervical fusion with an anatomically contoured threaded Steinmann-pin, which was secured to the occiput via small burr holes and to the vertebrae by sublaminar wiring, and supplemental autograft. This technique has the advantage over bone grafting, in that it affords rigid stabilization, allows early mobilization and may contribute to eventual bony fusion.
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Humans , Autografts , Bone Transplantation , Joint Dislocations , Down Syndrome , Early Ambulation , Incidence , Ligaments , Spinal Cord Diseases , Spineالملخص
Authors report a case of one-stage transoral decompression and posterior fusion in rheumatoid atlanto-axial subluxation. A 63-year-old man developed a rheumatoid atlantoaxial subluxation with mild weakness of all extremities which developed relatively suddenly 3 motnths after the initial symptom of neck pain. Skeletal traction followed by transoral decompression and occipitocervical fusion was performed on the same day. Postoperative course has been uneventful and revealed favorable fusion state of occipito-atlanto-axis. The pertinent literature on rheumatoid atlanto-axial subluxation is reviewed and discussed.
الموضوعات
Humans , Middle Aged , Decompression , Extremities , Neck Pain , Tractionالملخص
Authors report a case of one-stage transoral decompression and posterior fusion in rheumatoid atlanto-axial subluxation. A 63-year-old man developed a rheumatoid atlantoaxial subluxation with mild weakness of all extremities which developed relatively suddenly 3 motnths after the initial symptom of neck pain. Skeletal traction followed by transoral decompression and occipitocervical fusion was performed on the same day. Postoperative course has been uneventful and revealed favorable fusion state of occipito-atlanto-axis. The pertinent literature on rheumatoid atlanto-axial subluxation is reviewed and discussed.
الموضوعات
Humans , Middle Aged , Decompression , Extremities , Neck Pain , Tractionالملخص
We reviewed four patients who underwent posterior C-D occipitocervical loop and autogenous bone graft. The mean postoperative follow-up period was 16 months. The indications for surgery were progressive neurological deficit, atlantoaxial instability and intractable pain. Of the four patients, one had os odontoideum, two rheumatoid arthritis and suboccipital dislocation combined fractures of C1 and C2. Bong union was confirmed in all cases at approximately 4 months postoperatively. Final outcome result was satisfactory in three patients and unsatisfactory in one patient. The cause of unsatisfactory result was recurrent neck pain secondary to swan neck deformity. The neurologic deficit were improved or remained same as preoperative status. Three patient were out of bed on average of the 14th day postoperatively. One patient could not ambulate due to tetraplegia who needed an artificial ventilator. There was no complication related to instrumentation.