Artritis reumatoide de la columna cervical: aspectos clave para el cirujano ortopédico / Rheumatoid arthritis of the cervical spine: key aspects for the orthopedic surgeon

La artritis reumatoide es una enfermedad inflamatoria autoinmune crónica que afecta con frecuencia a la columna cervical. El diagnóstico clínico de la afección cervical puede ser difícil; por lo tanto, se recomienda la evaluación radiográfica sistemática de todos los pacientes. El tratamiento oportuno de estas lesiones es importante para preservar la independencia, la función neurológica, e, incluso, la vida de los pacientes. Este artículo es una revisión actualizada de todos los aspectos de la artritis reumatoide de la columna cervical relevantes para el cirujano ortopédico.

Rheumatoid arthritis is a chronic inflammatory autoimmune disease that frequently affects the cervical spine. The clinical diagnosis can be difficult; therefore, a systematic radiographic evaluation of all patients is recommended. The timely treatment of these lesions is important to preserve the self-reliance, the neurological function, and even the lives of the patients. The present article is an update of all the aspects pertaining to cervical spine rheumatoid arthritis that are relevant to the orthopedic surgeon.

Comparison of the efficacy of different decompressions treatment combined with posterior cervical fusion and internal fixation treatment on Chiari I malformation associated with syringomyelia and atlantoaxial instability / 中国基层医药

Objective@#To compare the efficacy of different decompressions treatment combined with posterior cervical fusion and internal fixation treatment on Chiari I malformation associated with syringomyelia and atlantoaxial instability.@*Methods@#From January 2016 to October 2017, 36 cases of Chiari I malformation associated with syringomyelia and atlantoaxial instability in Linfen People's Hospital were selected in the research.The patients were divided into two groups according to random number table method, with 18 cases in each group.The observation group was given decompression of posterior fossa of small bone window + cerebellar tonsillectomy + posterior cervical fusion and internal fixation treatment.The control group was given traditional decompression of posterior fossa + posterior cervical fusion and internal fixation treatment.The efficacy, complications occurred within 1 year after operation, JOA score and spinal cord cavity size at different time points before and after operation of the two groups were compared.@*Results@#The total effective rate of the observation group [94.44%(17/18)] was slightly higher than that of the control group [88.89%(16/18)] (χ2=1.957, P>0.05). The total effective rate of the observation group at 1 year after operation was 88.89%(16/18), which was significantly higher than that of the control group [72.22%(13/18)] (χ2=3.498, P<0.05). The incidence rate of complications of the observation group at 1 year after operation was 11.11%(2/18), which was significantly lower than that of the control group [38.89%(7/18)](χ2=11.685, P<0.05). The JOA scores at discharge[(15.97±1.25)point] and 1 year after operation[(15.53±1.19)point] of the observation group were significantly higher than those of the control group[(14.21±1.18)point, (14.06±1.15)point](t=3.815, 3.706, all P<0.05). The spinal cord cavity size at discharge [(2.13±0.64)mm] and 1 year after operation[(2.28±0.69)mm] of the observation group were significantly higher than those of the control group [(3.41±0.76)mm, (3.45±0.78)mm](t=5.743, 5.511, all P<0.05).@*Conclusion@#The long-term efficacy of decompression of posterior fossa of small bone window + cerebellar tonsillectomy + posterior cervical fusion and internal fixation treatment on Chiari I malformation associated with syringomyelia and atlantoaxial instability is remarkable, the recovery of spinal cord function and syringomyelia is well and the postoperative complications incidence is relatively low, which is worthy of popularization and application.

Anatomic Considerations of Anterior Transarticular Screw Fixation for Atlantoaxial Instability

STUDY DESIGN: Cadaveric, observational study.PURPOSE: Atlantoaxial instability (AAI) is characterized by excessive movement at the C1–C2 junction between the atlas and axis. An anterior surgical approach to expose the upper cervical spine for internal fixation and bone grafting has been developed to fix AAI. Currently, no anatomic information exists on the anterior transarticular atlantoaxial screw or screw and plate fixation between C1 and C2 in the Indian population. The objective of this study is to assess the anatomic landmarks of C1–C2 vertebrae: entry point, trajectory, screw length, and safety of the procedure.OVERVIEW OF LITERATURE: Methods outlined by Magerl and Harms are the optimal approaches among the dorsal techniques. Contraindications for these techniques include aberrant location of vertebral arteries, fractures of C1–C2 posterior structures. In these cases, anterior transarticular fixation is an alternative. Several available screw insertion trajectories have been reported. Biomechanical studies have demonstrated that adequate rigidity of this fixation is comparable with posterior fusion techniques.METHODS: Direct measurements using Vernier calipers and a goniometer were recorded from 30 embalmed human cadavers. The primary parameters measured were the minimum and maximum lateral and posterior angulations of the screw in the sagittal and coronal planes, respectively, and optimum screw length, if it was placed accurately.RESULTS: The posterior and lateral angles of screw placement in the coronal and sagittal planes ranged from 16° to 30° (mean±standard deviation [SD], 23.93°±3.93°) and 8° to 17° (mean±SD, 13.3°±2.26°), respectively. The optimum screw length was 25–38 mm (mean±SD, 28.76±3.69 mm).CONCLUSIONS: If the screw was inserted without lateral angulation, the spinal canal or cord could be violated. If a longer screw was inserted with greater posterior angulation, the vertebral artery at the posterior or posterolateral aspect of the C1 superior facet could be violated. Thus, 26° and 30° of lateral and posterior angulations, respectively, are the maximum angles permissible to avoid injury of the vertebral artery and violations of the spinal canal or atlanto-occipital joint.

Comparison of the efficacy of different decompressions treatment combined with posterior cervical fusion and internal fixation treatment on Chiari Ⅰ malformation associated with syringomyelia and atlantoaxial instability / 中国基层医药

Objective To compare the efficacy of different decompressions treatment combined with posterior cervical fusion and internal fixation treatment on Chiari Ⅰ malformation associated with syringomyelia and atlantoaxial instability.Methods From January 2016 to October 2017,36 cases of Chiari Ⅰ malformation associated with syringomyelia and atlantoaxial instability in Linfen People's Hospital were selected in the research.The patients were divided into two groups according to random number table method,with 18 cases in each group.The observation group was given decompression of posterior fossa of small bone window + cerebellar tonsillectomy + posterior cervical fusion and internal fixation treatment.The control group was given traditional decompression of posterior fossa + posterior cervical fusion and internal fixation treatment.The efficacy,complications occurred within 1 year after operation,JOA score and spinal cord cavity size at different time points before and after operation of the two groups were compared.Results The total effective rate of the observation group [94.44％ (17/18)] was slightly higher than that of the control group [88.89％ (16/18)] (x2 =1.957,P ＞ 0.05).The total effective rate of the observation group at 1 year after operation was 88.89％ (16/18),which was significantly higher than that of the control group [72.22％ (13/18)] (x2 =3.498,P ＜ 0.05).The incidence rate of complications of the observation group at 1 year after operation was 11.11％ (2/18),which was significantly lower than that of the control group [38.89％ (7/18)] (x2 =11.685,P ＜ 0.05).The JOA scores at discharge[(15.97 ± 1.25) point] and 1 year after operation[(15.53 ± 1.19) point] of the observation group were significantly higher than those of the control group [(14.21 ± 1.18) point,(14.06 ±1.15) point] (t =3.815,3.706,all P ＜ 0.05).The spinal cord cavity size at discharge [(2.13 ± 0.64) mm] and 1 year after operation [(2.28 ± 0.69) mm] of the observation group were significantly higher than those of the control group [(3.41 ±0.76)mm,(3.45 ±0.78)mm] (t =5.743,5.511,all P＜0.05).Conclusion The long-term efficacy of decompression of posterior fossa of small bone window + cerebellar tonsillectomy + posterior cervical fusion and internal fixation treatment on Chiari Ⅰ malformation associated with syringomyelia and atlantoaxial instability is remarkable,the recovery of spinal cord function and syringomyelia is well and the postoperative complications incidence is relatively low,which is worthy of popularization and application.

Influence of Atlantoaxial Fusion on Sagittal Alignment of the Occipitocervical and Subaxial spines in Os Odontoideum with Atlantoaxial Instability

STUDY DESIGN: Retrospective case analysis. PURPOSE: We hypothesized that larger the C1–C2 fusion angle, greater the severity of the sagittal malalignment of C0–C1 and C2–C7. OVERVIEW OF LITERATURE: In our experience, instances of sagittal malalignment occur at C0–C1 and C2–C7 following atlantoaxial fusion in patients with Os odontoideum (OO). METHODS: We assessed 21 patients who achieved solid atlantoaxial fusion for reducible atlantoaxial instability secondary to OO. The mean patient age at the time of the operation was 42.8 years, and the mean follow-up duration was 4.9 years. Radiographic parameters were preoperatively measured and at the final follow-up. The patients were divided into two groups (A and B) depending on the C1–C2 fusion angle. In group A (n=11), the C1–C2 fusion angle was ≥22°, whereas in group B, it was <22°. The differences in the radiographic parameters of the two groups were evaluated. RESULTS: At the final follow-up, the C1–C2 angle was increased. However, this increase was not statistically significant (18° vs. 22°, p=0.924). The C0–C1 angle (10° vs. 5°, p<0.05) and C2–C7 angle (22° vs. 13°, p<0.05) significantly decreased. The final C1–C2 angle was negatively correlated with the final C0–C1 and C2–C7 angles. The final C0–C1 angle (4° vs. 6°, p<0.05) and C2–C7 angle (8° vs. 20°, p<0.05) were smaller in group A than in group B. After atlantoaxial fusion, the C0–C1 range of motion (ROM; 17° vs. 9°, p<0.05) and the C2–C7 ROM (39° vs. 31°, p<0.05) were significantly decreased. CONCLUSIONS: We found a negative association between the sagittal alignment of C0–C1 and C2–C7 after atlantoaxial fusion and the C1–C2 fusion angle along with decreased ROM. Therefore, overcorrection of C1–C2 kyphosis should be avoided to maintain good physiologic cervical sagittal alignment.

Posterior Sublaminar Wiring and/or Transarticular Screw Fixation for Reducible Atlantoaxial Instability Secondary to Symptomatic Os Odontoideum: A Neglected Technique?

STUDY DESIGN: Retrospective case analysis. PURPOSE: We retrospectively evaluated the clinical and radiological outcomes of posterior sublaminar wiring (PSLW) and/or transarticular screw fixation (TASF) for reducible atlantoaxial instability (AAI) secondary to os odontoideum. OVERVIEW OF LITERATURE: Limited information is available about the surgical outcomes of symptomatic os odontoideum with AAI. METHODS: We examined 23 patients (12 women and 11 men) with os odontoideum and reducible AAI. The average age of the patients at the time of the operation was 44.2 years. The average follow-up duration was 4.5 years. Thirteen patients with anterior AAI underwent PSLW alone, while 10 patients with combined (anterior+posterior) AAI underwent PSLW and TASF. An autogenous iliac bone graft was used for all patients. Nine patients complained of neck or suboccipital pain, and 14 complained of myelopathy. RESULTS: Angulational instability (preoperative 18.7°±8.9° vs. postoperative 2.1°±4.6°, p<0.001), translational instability (16.3±4.9 mm vs. 1.8±2.2 mm, p<0.001), and segmental angle of the C1–C2 joint (23.7°±7.2° vs. 28.4°±3.8°, p<0.05) showed significant improvement postoperatively. Neck Visual Analog Scale score (6.2±2.4 vs. 2.5±1.8, p<0.05) and the modified Japanese Orthopedic Association (9.1±3.1 vs. 13.2±2.6, p<0.05) score also improved, with a recovery rate of 51.8%. Among the three patients who developed nonunion and/or wire breakage, one underwent revision surgery with repeat PSLW and was finally able to achieve fusion. The final fusion rate was 91.3%. CONCLUSIONS: PSLW and/or TASF provided satisfactory clinical and radiological outcomes in reducible AAI secondary to os odontoideum without significant neurological complications. Our results suggest that PSLW and/or TASF can be considered a viable surgical option over segmental fixation in highly selected cases of os odontoideum with reducible AAI.

The research progress of posterior atlantoaxial internal fixation techniques / 医学研究生学报

Atlantoaxial instability or dislocation is a common upper cervical disease which can lead to serious outcomes including sensory and motor deficit or even sudden death. Therefore, active surgical intervention is often recommended. The most popular surgical procedure for atlantoaxial instability is posterior bone graft and internal fixation. Posterior stabilization techniques mainly include wiring techniques, interlaminar clamp fixation, C1-C2 transarticular screw fixation (Magerl technique), screw-plate systems, and screw-rod systems. Each technique has its advantage and shortcoming. The screw-rod systems, along with various modifications, has become the most popular internal fixation technique for posterior atlantoaxial stabilization in clinic. This article reviews the evolution, characteristics and new advancement of some prevail posterior atlantoaxial fixation techniques in purpose of giving a reference for surgeons to have a better understanding of posterior fixation techniques and make a reasonable choice in clinical practice.

Atlantoaxial reduction and fixation guided by the intraoperative CT / 北京大学学报(医学版)

Objective: To evaluate the clinical result of atlantoaxial reduction and fixation guided by the intraoperative CT.Methods: Sixteen cases were retrospectively studied, including seven males and nine females, with the mean age of 49.9 years.Twelve cases were diagnosed as chronic atlantoaxial instability or dislocation, while four cases as acute odontoid fracture and dislocation.Among the sixteen cases, fourteen underwent atlantoaxial fusion, while two underwent temporary atlantoaxial fixation without fusion.The intraoperative CT was used in the setting of: 1.Evaluating the atlantoaxial reduction before the screw insertion;2.Guiding the C1 and C2 pedicle drilling (two cases using additional three-dimensional printing drilling template);3.Evaluating the position of the screws and reduction after the atlantoaxial fixation.In addition, three-dimensional drilling template combined with intraoperative CT was used in two cases.CT scanning frequency was calculated.To evaluate the accuracy rate of screw fixation under the intraoperative CT, 19 cases without the intraoperative CT were studied as the control group.Results: Averaged CT scanning frequency was 1.4 times (Once in eleven cases, twice in four and three times in one).Among the sixteen cases, mal-positioned C1 screws were found and revised in two cases.No spinal cord injury or vertebral artery injury occurred.The follow-up ranged from three to ten months, with the mean of 6.7 months.Fourteen cases achieved solid osseous fusion, and two with temporary fixation had odontoid fracture union.Anatomic reduction was achieved in all the cases.Eleven cases with preoperative myelopathy had postoperative improvement and their mean JOA scores improved from 12.1 to 14.4.To the last follow-up, no hardware complications were found including screw broken, rod broken or fixation loosening.All the screws of intraoperative CT group had good positions.For 19 cases of the control group, there were two cases of mal-positioned screws (10.5%).Conclusion: Advantages of atlantoaxial reduction and fixation guided by the intraoperative CT included: improving the accuracy of the atlantoaxial screws, exactly evaluating the reduction of the atlantoaxial joint, immediately discovering the mal-positioned screws and avoiding the revision surgery.A good clinical result was found in the preliminary study.

Comparison of Cervical Alignment and Clinical Outcomes in Patients with Os Odontoideum versus Non-Os Odontoideum after Atlantoaxial Fixation

OBJECTIVE: The purpose of this study was to compare the effect of atlantoaxial fixation on cervical alignment and clinical outcomes in patients with os odontoideum (OO) versus non-os odontoideum (non-OO). METHODS: A total of 119 patients who underwent atlantoaxial fixation for instability were identified between January 1998 and January 2014. Inclusion criteria included age more than 21 years and diagnosis of OO and non-OO. There were 22 OO patients, and 20 non-OO patients. Measuring the Oc–C1 Cobb angle, C1–2 Cobb angle, C2–7 Cobb angle, and C2–7 sagittal vertical axis (SVA) was assessed. Clinical outcome was assessment of suboccipital pain was determined using a visual analogue scale (VAS), and Japanese Orthopedic Association (JOA) scores were obtained in all patients pre- and postoperatively. RESULTS: The preoperative C1–2 angle in the OO group (26.02°±10.53°) was significantly higher than the non-OO group (p=0.04). After C1–2 fixation, the OO group had significantly higher kyphotic change in the C1–2 angle (ΔC1–2) (3.2°±7.3° [OO] vs. −1.46°±7.21° [non-OO]) (p=0.04), and higher decrease in postoperative C2–7 SVA (ΔC2–7 SVA) (5.64±11.56 mm [OO] vs. −0.51± 6.57 mm [non-OO]) (p=0.04). Both groups showed improvements in the health related quality of life (HRQOL) after surgery based on the VAS and JOA score (p < 0.001). CONCLUSION: After fixation, kyphotic angular change in atlantoaxial joint and decrease C2–7 SVA were marked in the OO group. Both the OO and non-OO groups improved in neurological function and outcome after surgery.

Challenges of Transarticular Screw Fixation in Young Children: Report of Surgical Treatment of a 5-Year-Old Patient's Unstable Os-Odontoideum

Surgical procedures for atlantoaxial (C1–C2) fusion in young children are relatively uncommon. The purpose of this study was to report on a surgical treatment for a case of atlantoaxial instability caused by os-odontoideum in association with quadriparesis and respiratory paralysis in a 5-year-old girl. We present the patient's history, physical examination, and radiographic findings, describe the surgical treatment and a five year follow-up, and provide a literature review. The instability was treated by halo immobilization, followed by C1–C2 transarticular screw fixation using a computed tomography-based navigation system. At the five year follow-up, the patient had made a complete recovery with solid union. The authors conclude that C1–2 transarticular screw fixation is technically possible as in a case of atlantoaxial instability in a five-year-old child.

Posterior atlantoaxial transpedicle screw fixation for traumatic atlatoaxial instability / 解放军医学杂志

Objective To explore the clinical efficacy of posterior atlantoaxial pedicle screw fixation for traumatic atlantoaxial instability. MethodsFrom September 2009 to March 2013, 17 patients with atlantoaxial instability received posterior atlantoaxial pedicle screw fixation. There were 12 males and 5 females, with a mean age of 42 years old (ranged from 19 to 63 years old). Transpedicle screw fixation was employed in 8 patients with atlantoaxial fracture and dislocation, in 2 with traumatic disruption of transverse atlantal ligament, and in 7 with odontoid fracture. The Japanese Orthopaedic Asso ciation (JOA) score before operation was from 5 to 14, with a mean of 11.2. Preoperative CT, MRI and radiographs, as well as intraoperative screw placement and bone graft were administered in all the patients. ResultsIn all the patients, complete reduction was achieved without injury to the vertebral artery, spinal cord or never root, and they started to be ambulatory on the first day after the operation. The patients were followed up for 6-36 months (mean 21 months), and clinical symptoms were seen to be improved significantly. Imaging reexamination 6 months after the surgery showed satisfactory healing of implanted bone and position of all the screws without loosening of the implant. The mean JOA scores was 15.5(11.0-17.0) twelve months after the operation. Conclusion Atlantoaxial pedicle screw fixation for traumatic atlantoaxial instability is safe and reliable with a favorable clinical result.

Comparison between Bilateral C2 Pedicle Screwing and Unilateral C2 Pedicle Screwing, Combined with Contralateral C2 Laminar Screwing, for Atlantoaxial Posterior Fixation

STUDY DESIGN: A retrospective study. PURPOSE: To compare clinical and radiological outcomes between bilateral C2 pedicle screwing (C2PS) and unilateral C2PS, combined with contralateral C2 laminar screwing (LS), for posterior atlantoaxial fixation. OVERVIEW OF LITERATURE: Posterior fixation with C1 lateral mass screwing (C1LMS) and C2PS (C1LMS-C2PS method) is an accepted procedure for rigid atlantoaxial stabilization. However, conventional bilateral C2PS is not always allowed in this method due to anatomical variations of C2 pedicles and/or asymmetry of the vertebral artery. Although unilateral C2PS plus contralateral LS (C2PS+LS) is an alternative in such cases, the efficacy of this procedure has not been evaluated in controlled studies (i.e., with bilateral C2PS as a control). METHODS: Clinical and radiological records of patients who underwent the C1LMS-C2PS method, using unilateral C2PS+LS (n=9), and those treated using conventional bilateral C2PS (n=10) were compared, with a minimum two years follow-up. RESULTS: Postoperative complications related to the unilateral C2PS+LS technique included one case of spontaneous spinous process fracture of C2. A C1 anterior arch fracture occurred after a fall in one patient, who underwent bilateral C2PS and C1 laminectomy. No significant differences were seen between the groups in reduction of neck pain after surgery or improvement of neurological status, as evaluated using the Japanese Orthopaedic Association score. A delayed union occurred in one patient each of the groups, with the final fusion rate being 100% in both groups. CONCLUSIONS: Clinical and radiological outcomes of unilateral C2PS+LS were comparable with those of the bilateral C2PS fixation technique for the C1LMS-C2PS method.

Remoção da cartilagem articular associada ou não a implante homógeno ou enxerto autógeno de osso esponjoso em cães submetidos à artrodese atlantoaxial / Joint cartilage removal associated or not to homologous implant or autologous cancellous bone graft in dogs submitted to atlantoaxial arthrodesis

O objetivo deste estudo foi avaliar o grau de fusão articular e formação óssea na articulação atlantoaxial de cães submetidos à artrodese após a remoção da cartilagem articular associada ou não ao implante homógeno ou enxerto autógeno de osso esponjoso. Foram utilizados 12 cães, adultos, distribuídos aleatoriamente em três grupos iguais. Grupo I (GI): realizada apenas a remoção da cartilagem articular e imobilização articular com pinos e resina acrílica. Grupo II (GII): feita a remoção da cartilagem articular e imobilização da articulação, seguida da colocação e modelagem do implante ósseo esponjoso homógeno entre as superfícies articulares. Grupo III (GIII): foi realizado o mesmo procedimento do GII, mais o enxerto ósseo esponjoso autógeno no local determinado. Realizaram-se exames radiográficos em todos os animais aos 30, 60 e 90 dias de pós-operatório (PO). Aos 90 dias de PO foi feita a eutanásia para o emprego do teste de palpação manual, avaliação tomográfica e histopatológica. Para análise estatística da associação entre o grau de fusão articular, aplicou-se o Teste Qui-quadrado de independência. Os resultados dos testes foram avaliados pela significância exata e considerados significantes a 5% (P<0,05). Pelo teste de palpação manual e pelas imagens tomográficas, não houve diferença entre os grupos aos 90 dias de PO. A análise radiográfica da articulação atlantoaxial mostrou que o grau de fusão era semelhante entre os tratamentos entre os tempos de evolução. Com relação ao estudo histopatológico da articulação atlantoaxial dos cães, decorridos 90 dias de PO, foi verificado que a proliferação óssea no grupo I apresentou grau de intensidade proporcional, no grupo II, 75% leve e 25% acentuada e, no grupo III, 25% moderada e 75% acentuada. Não existe diferença quanto ao grau de fusão articular e formação óssea quando a técnica de artrodese atlantoaxial em cães for associada ao enxerto de osso esponjoso autógeno ou implante homógeno. A remoção da cartilagem articular isoladamente é uma alternativa eficiente e apresenta resultados semelhantes, quando associada ao enxerto autógeno ou implante homógeno.

The aim of this study was to evaluate the degree of joint fusion and bone formation in dogs undergoing atlantoaxial arthrodesis after removal of articular cartilage associated or not to implant homogenous or autogenous cancellous bone. Twelve dogs, weighing between 8 and 12kg were randomly divided into three groups. Group I (GI) performed only the removal of joint cartilage and joint immobilization with acrylic resin and pins. Group II (GII): after removel of joint cartilage and articular immobilization was performed modeling and placement of homogenous cancellous bone at the given location. The volume of homograft placed in the joint was measured using a precision balance and all animals received the same amount. Group III (GIII): this was the same procedure as GI, however, was used autogenous cancellous bone graft at the given location. Radiographic examinations were performed on all animals at 30, 60 and 90 days postoperatively. At 90 days of PO was carried out euthanasia of animals for testing of manual palpation and CT evaluation and histological. Samples were kept in solution in 10% buffered formaldehyde for fixation for a minimum of 72 hours and after, decalcified in formic acid and sodium citrate for subsequent processing and included in paraffin. Sections were stained with hematoxylin-eosin for light microscopy evaluation. Statistical analysis of the association between the degree of joint fusion assessed by manual palpation, the digitized radiographic images and CT scans and treatment groups, we applied the Chi-square test of independence. The test results were evaluated by the exact significance and considered statistically significant at 5% significance (P<0.05). By manual palpation test and by the CT images can be seen that there was no statistically significant difference between groups at 90 days postoperatively. Radiographic analysis of the atlantoaxial joint showed that the degree of fusion was similar among treatments, no statistical difference at 30, 60 and 90 days postoperatively. Regarding the histopathological study of atlantoaxial joint of dogs after 90 days postoperatively was found that bone formation in group I had 25% of each intensity (absent, mild, moderate, severe) in group II, 75% lighter and 25% sharp and in group III, 25% moderate and 75% severe. It can be concluded that the use of graft homogenous preserved in 98% glycerin in dogs undergoing atlantoaxial fusion method is a viable alternative for treatment of atlantoaxial instability. There is no difference in the degree of joint fusion and bone formation when the technique of atlantoaxial arthrodesis in dogs is associated with autogenous cancellous bone graft or implant homogenous. The removal of articular cartilage alone is an effective and shows similar results to the use of autograft or homogenous implant.

Asymptomatic moyamoya syndrome, atlantoaxial subluxation and basal ganglia calcification in a child with Down syndrome / 소아과

Down syndrome, the most common chromosomal abnormality, may be associated with various neurologic complications such as moyamoya syndrome, cervical spinal cord compression due to atlantoaxial subluxation, and basal ganglia damage, as well as epileptic seizures and stroke. Many cases of Down syndrome accompanied by isolated neurologic manifestations have been reported in children; however, Down syndrome with multiple neurologic conditions is rare. Here, we have reported a case of Down syndrome in a 10-year-old girl who presented with asymptomatic moyamoya syndrome, atlantoaxial subluxation with spinal cord compression, and basal ganglia calcification. To the best of our knowledge, this is the first report of Down syndrome, in a child, which was accompanied by these 3 neurologic complications simultaneously. As seen in this case, patients with Down syndrome may have neurologic conditions without any obvious neurologic symptoms; hence, patients with Down syndrome should be carefully examined for the presence of neurologic conditions.

Intraoperative Vertebral Artery Angiography to Guide C1-2 Transarticular Screw Fixation in a Patient with Athetoid Cerebral Palsy

We present a case of an athetoid cerebral palsy with quadriparesis caused by kyphotic deformity of the cervical spine, severe spinal stenosis at the cervicomedullary junction, and atlantoaxial instability. The patient improved after the first surgery, which included a C1 total laminectomy and C-arm guided righ side unilateral C1-2 transarticular screw fixation. C1-2 fixation was not performed on the other side because of an aberrant and dominant vertebral artery (VA). Eight months after the first operation, the patient required revision surgery for persistent neck pain and screw malposition. We used intraoperative VA angiography with simultaneous fluoroscopy for precise image guidance during bilateral C1-2 transarticular screw fixation. Intraoperative VA angiography allowed the accurate insertion of screws, and can therefore be used to avoid VA injury during C1-2 transarticular screw fixation in comorbid patients with atlantoaxial deformities.

Computer-assisted C1-C2 Transarticular Screw Fixation "Magerl Technique" for Atlantoaxial Instability

STUDY DESIGN: A retrospective study. PURPOSE: To evaluate the surgical results of computer-assisted C1-C2 transarticular screw fixation for atlantoaxial instability and the usefulness of the navigation system. OVERVIEW OF LITERATURE: We used a computed tomography (CT)-based computer navigation system in planning and screw insertion in Magerl's procedure, which provides the most rigid atlantoaxial fusion, to avoid risk of vertebral artery (VA) tear by avoiding high-riding VA during screw insertion. METHODS: Twenty patients who underwent atlantoaxial fusion under the CT-based navigation system were studied. The mean observation period was 33.5 months. The evaluated items included the existence of VA stenosis by preoperative magnetic resonance angiography, surgical time, blood loss volume, Japanese Orthopaedic Association (JOA) score and Ranawat's pain criteria before surgery and at final follow-up, postoperative screw position evaluated by CT, and bony fusion. RESULTS: The mean operation time was 205 minutes, with the mean blood loss volume of 242 ml. The mean JOA score was 11.6 points before surgery and 13.7 at final follow-up. Occipital and/or cervical pain presented before operation was remitted or resolved in all patients. Evaluation of screw insertion by CT revealed correct penetration to atlantoaxial joints, with a perforation rate of 2.6%. There was no complication, including VA tear, and all patients who were followed-up during one year or more after surgery achieved bony fusion. Some subjects who appeared inappropriate for surgery from CT images were assessed as eligible for surgery based on the evaluation results obtained using the navigation system. CONCLUSIONS: It was demonstrated that the CT-based navigation system is an effective support device for Magerl's procedure.

Mielopatia cervical por instabilidade atlanto-axial em portadora de trissomia do 21: diagnóstico neurofisiológico / Cervical myelopathy by atlantoaxial instability in a patiente with trisomy 21

Os autores apresentam o caso de uma mulher portadora da síndrome de Down com um quadro de paraparesia assimétrica de maior gravidade no lado esquerdo há sete meses, sem sintomas sensitivos ou autonômicos. Foi encaminhada para realização de investigação neurofisiológica especificamente a eletroneuromiografia. Os autores descrevem a estratégia da investigação neurofisiológica para evidenciar a mielopatia e demonstram a presença de subluxação atlanto-axial por Raio X e Tomografia computadorizada.

The authors present a clinical case of a woman with Down syndrome and an asymmetric paraparesis, more severe on the left side, for seven months, without sensory or autonomic symptoms. She was sent for neurophysiological evaluation, specifically electromyography. The authors describe a neurophysiological strategy in order to evidence the involvement of cervical medulla and conluded to be a cases of atlanto-axial subluxation by X-ray and Computed Tomography.

Targeting a Safe Entry Point for C2 Pedicle Screw Fixation in Patients with Atlantoaxial Instability

OBJECTIVE: This investigation was conducted to evaluate a new, safe entry point for the C2 pedicle screw, determined using the anatomical landmarks of the C2 lateral mass, the lamina, and the isthmus of the pars interarticularis. METHODS: Fifteen patients underwent bilateral C1 lateral mass-C2 pedicle screw fixation, combined with posterior wiring. The C2 pedicle screw was inserted at the entry point determined using the following method : 4 mm lateral to and 4 mm inferior to the transitional point (from the superior end line of the lamina to the isthmus of the pars interarticularis). After a small hole was made with a high-speed drill, the taper was inserted with a 30 degree convergence in the cephalad direction. Other surgical procedures were performed according to Harm's description. Preoperatively, careful evaluation was performed with a cervical X-ray for C1-C2 alignment, magnetic resonance imaging for spinal cord and ligamentous structures, and a contrast-enhanced 3-dimensional computed tomogram (3-D CT) for bony anatomy and the course of the vertebral artery. A 3-D CT was checked postoperatively to evaluate screw placement. RESULTS: Bone fusion was achieved in all 15 patients (100%) without screw violation into the spinal canal, vertebral artery injury, or hardware failure. Occipital neuralgia developed in one patient, but this subsided after a C2 ganglion block. CONCLUSION: C2 transpedicular screw fixation can be easily and safely performed using the entry point of the present study. However, careful preoperative radiographic evaluation, regardless of methods, is mandatory.

Vertical Reduction Using Atlantoaxial Facet Spacer in Basilar Invagination with Atlantoaxial Instability

Although posterior segmental fixation technique is becoming increasingly popular, surgical treatment of craniovertebral junctional disorders is still challenging because of its complex anatomy and surrounding critical neurovascular structures. Basilar invagination is major pathology of craniovertebral junction that has been a subject of clinical interest because of its various clinical presentations and difficulty of treatment. Most authors recommend a posterior occipitocervical fixation following transoral decompression or posterior decompression and occipitocervical fixation. However, both surgical modalities inadvertently sacrifice C0-1 and C1-2 joint motion. We report two cases of basilar invagination reduced by the vertical distraction between C1-2 facet joint. We reduced the C1-2 joint in an anatomical position and fused the joint with iliac bone graft and C1-2 segmental fixation using the polyaxial screws and rods C-1 lateral mass and the C-2 pedicle.

Successful general anesthesia for cervical spine fusion in a patient with spondyloepiphyseal dysplasia congenita: A case report

Spondyloepiphyseal dysplasia congenita (SEDC) is a kind of skeletal dysplasia, inheritable condition. The clinical features of SEDC are dwarfism, myopia with or without retinal detachment, coxa vara, thoracic dysplasia with respiratory failure and laryngotracheal stenosis. A point of particular concern to anesthetists is odontoid hypoplasia which, combined with ligamentous laxity, leads to atlantoaxial instability. We report successful general anesthesia for cervical spine fusion of a patient with SEDC.