Posterior Occipitocervical Fixation Research Articles

C2 pedicle screw insertion assisted by mobilization of the vertebral artery in cases with high-riding vertebral artery

ObjectiveTo describe the feasibility, safety and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with the high-riding vertebral artery (HRVA). MethodsDuring the period January 2020 to September 2022, fifteen patients underwent posterior occipitocervical fixation in our department. All patients had unilateral HRVA on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 13 females aged 47 ± 11.9 years (range: 17–64 years). After the correction of the vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. A routine three-dimensional reconstructed CT examination was executed to confirm the trajectory of C2 pedicle screws post-operation, and a CT angiography examination was performed when necessary. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including anterior atlantodental interval (ADI), the distance of odontoid tip above Chamberlain line, and clivus-canal angle (CCA), were collected and compared by paired t-test. ResultsAll 15 patients had atlas assimilation, among which 12 patients had C2–C3 fusion (Klippel-Feil syndrome). Mobilization of the HRVA was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were reached in all 15 patients. All the patients achieved bone fusion 6 months after surgery. No looseness and shift of internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative JOA score and the main radiological measurements were remarkably improved and statistically significant. ConclusionsC2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.

Long-term results of treatment of a patient with basilar invagination complicated by distal kyphosis and compressive ischemic cervical myelopathy: a clinical case and a brief literature review

Objective. To present a clinical case of surgical correction of a craniovertebral anomaly complicated after 8 years by distal junctional kyphosis, stenosis, antelisthesis of the C5 vertebra and compressive ischemic cervical myelopathy in the C5–C6 segment.Material and Methods. When treating a 56-year-old patient with multiple anomalies of the craniovertebral region, differentiated surgical technologies were consistently used due to the development of late complications. The sequence and rationale for surgical decision making is described.Results. Initially, the patient underwent transoral decompression and posterior occipitocervical fixation, and after 8 years - reinstallation of the system with distal extension of the instrumentation zone to the C7 vertebra with indirect posterior decompression of the spinal cord, anterior discectomy with direct decompression and cage fixation at the C5–C6 level. Regression of myelopathic syndrome, correction of orthopedic status and significant improvement in functional status were achieved.Conclusion. A rare clinical observation demonstrates a combination of basilar invagination with assimilation of the atlas, which has provided rationale for two-stage surgical treatment in one surgical session (1st stage – transoral resection of the dens and 2/3 of the C2 vertebral body with anterior decompression of the spinal cord, and 2nd stage – occipitocervical fixation). The use of extended systems in this case caused the development of a clinically significant syndrome of the distal adjacent level, which required repeated surgical treatment after 8 years.

Anterior atlanto-occipital transarticular screw fixation: a biomechanical comparison with posterior fixation techniques.

Atlanto-occipital instability is commonly treated with posterior fixation. However, in patients with congenital or acquired factors, posterior fixation may not be possible. For these situations, a novel anterior atlanto-occipital transarticular screw (AATS) fixation technique has been introduced recently. However, biomechanical study of this technique is lacking. This study was designed to evaluate the biomechanical stability of AATS fixation for the atlanto-occipital joint and compare it with conventional posterior occipitocervical fixation (POCF). Six cadaveric specimens (occiput-C4) were tested in four conditions, including intact, injury, injury + AATS, and injury + POCF states. A pure moment of 1.5 Nm was applied to specimens in flexion, extension, lateral bending, and axial rotation. The range of motion (ROM) and neutral zone (NZ) were calculated and compared from the occiput to C1. The AATS fixation constrained ROMs to 0.4° in flexion (p < 0.001), 0.4° in extension (p < 0.001), 1.0° in lateral bending (p < 0.001), and 0.7° in axial rotation (p < 0.001) when compared with the injury state. In all directions, there was no statistically significant difference observed in ROMs and NZs between AATS fixation and POCF (p > 0.05). This study identified that the novel AATS fixation, as stand-alone anterior fixation, was equivalent to POCF in all directions. The results suggest that anterior transarticular screw fixation is a biomechanically effective salvage technique for posterior atlanto-occipital fixation, and may also serve as supplemental fixation.

Incidence and management of surgical site infection in the cervical spine following a transoral approach.

Transoral approach can accomplish ventral decompression directly. However, surgical site infection (SSI) cannot be ignored. This paper aims to review the prevalence of infection and conduct advice for the treatment of SSI in the cervical spine following the transoral approach. A retrospective analysis of patients with SSI after transoral atlantoaxial reduction plate (TARP) surgery was performed. SSI was classified into three kinds according to the modified American CDC criteria. 2.9% (17/581) patients who underwent TARP surgery, experienced SSI, of which five had superficial SSI (SI), eight had deep SSI (DI), and four had organ/space SSI (O/SI). The patients with SI underwent intravenous antibiotic treatment and were ultimately cured. Among the remaining 12 patients with DI and O/SI, 11 underwent reoperation for TARP system removal and subsequently one-stage posterior occipitocervical fixation, and one patient experienced infection twomonths post-operatively and died without receiving treatment. Among patients who underwent revision surgery, three experienced intracranial infection due to intra-operative dural tears, and continuous lumbar cerebrospinal fluid drainage and intrathecal injection of antibiotics were used as effective and appropriate treatments, with outcomes of one recovery and two deaths. All patients with SSI were begun on intravenous antibiotics with conversion to oral antibiotics. The incidence of SSI was 2.9% (17/581). Adequate peri-operative preparation, early diagnosis, and appropriate treatment of SSI require further research.

Degenerative occipitocervical dislocation – Uncommon entity at extreme of Life: A case report and review of literature

Traumatic occipitocervical dislocation (OCD) has been reported numerous times both in children and adults. Nontraumatic OCD is rare. An 85-year-male referred with 2 months history of motor and sensory complaints in all four limbs. There was no history of trauma. Neck movements were restricted. A lateral radiograph of the cervical spine was suggestive of extensive degenerative changes in the cervical spine. Computed tomography scan of the cervical spine revealed posterior OCD with degenerative changes. Magnetic resonance imaging revealed compressive myelopathy at the cervico-medullary junction. Posterior occipitocervical fixation was performed. His neurological symptoms significantly improved. The procedure resulted in an excellent immediate and long-term clinical outcome.

Safety, efficacy, surgical, and radiological outcomes of short segment occipital plate and C2 transarticular screw construct for occipito-cervical instability.

Objective:Our study aims to assess the safety, efficacy, clinicoradiological, functional, neurological outcomes, and complications of posterior occipitocervical fixation using an occipital plate and C1-2 transarticular screw (TAS) construct.Study Design:This was a retrospective analysis of prospectively collected data.Methods:Data of 27 patients who underwent occipital plate and C1-2 TAS construct at a single institute from 2010 to 2015 were collected and analyzed. Demographics, clinical parameters (Visual Analog Score, Oswestry Disability Index, and modified JOA score), radiological parameters – mean atlantodens interval, posterior occipitocervical angle, occipitocervical-2 angle, surgical parameters (operative time, blood loss, hospital stay, and fusion), and complications were evaluated.Results:The mean age of the patients was 54.074 ± 16.52 years (18–81 years), the mean operative time was 116.29 ± 12.23 min, and the mean blood loss was 196.29 ± 38.94 ml. The mean hospital stay was 5.22 ± 1.28 days. The mean ± standard deviation follow-up duration was 62.52 ± 2.27 months. There was a significant improvement in clinical parameters and radiological parameters postoperatively. One patient with implant failure, one patient with pseudoarthrosis, one with neurological deterioration, two wound complications, and two dural tears were noted.Conclusion:Posterior occipitocervical reconstruction with O-C1-2 TAS construct provided excellent clinical outcomes, radiological outcomes, optimal correction of malalignment in the occipitocervical region, and with biomechanically sound fixation. Extending the instrumentation into the subaxial spine will lead to a decrease in the range of motion, increased surgical time, blood loss, more extensive muscle damage, and also increase the costs.

Increase of the clivus-canal angle in patients with basilar invagination, without atlantoaxial displacement, treated with a simple maneuver of indirect decompression of the odontoid with the head clamp, during posterior occipitocervical arthrodesis.

Background: Basilar invagination (BI) can be defined as the insinuation of the content of the craniovertebral junction through the foramen magnum toward the posterior fossa. BI is a prevalent condition in Northeast Brazil. The present study describes the changes in the clivus-canal angle (CCA) in the postoperative period in patients with symptomatic BI operated by a posterior approach, using a simple technique of indirect reduction of the odontoid associated with occipitocervical fixation.Methods: Patients underwent radiological evaluations by magnetic resonance imaging in the pre and postoperative periods, where the height of the odontoid tip was measured in relation to the Chamberlain line and the ACC. All patients underwent posterior occipitocervical fixation with specific maneuvers of distraction and extension of the cephalic segment with the aid of a head clamp with three fixation points for anterior reduction of the odontoid.Results: Among the 8 patients evaluated in the series, all had increased ACC in the postoperative period, with a mean of 14.81 ± 1.54°, and statistically significant difference between the pre and postoperative periods (P < 0.05).Conclusion: The indirect surgical reduction of the odontoid process by a posterior approach through the manipulation (distraction-extension) of a “Mayfield” type of head clamp followed by occipitocervical fixation proved to be effective in improving the ACC, being easily reproducible.

Treatment strategy and curative effect analysis of os odontoideum complicated with atlantoaxial joint dislocation

To explore the treatment strategy and clinical efficacy for os odontoideum complicated with atlantoaxial dislocation. The clinical data of 17 patients with os odontoideum complicated with atlantoaxial dislocation surgically treated from January 2006 to January 2015 were retrospectively analyzed, including 7 males and 10 females, aged 17 to 53 (43.1±11.3) years old;course of disease was 3 to 27(10.2±6.9) months. All patients received cranial traction before operation, 12 of 14 patients with reducible dislocation were treated by posterior atlantoaxial fixation and fusion, and 2 patients with atlantooccipital deformity were treated by posterior occipitocervical fixation and fusion;3 patients with irreducible alantoaxial dislocation were treated by transoral approach decompression combined with posterior atlantoaxial fixation and fusion. The operation time, intraoperative blood loss and perioperative complications were recorded. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the change of neck pain and neurological function. Atlantoaxial joint fusion rate was evaluated by CT scan. The operation time of posterior fixation and fusion ranged from 86 to 170 (92.2±27.5) min, and the intraoperative blood loss was 200-350 (250.7±65.2) ml. No vertebral artery injury and spinal cord injury were recorded. Among the patients underwent atlantoaxial fixation and fusion, 1 patient with reducible dislocation fixed by C2 laminar screw lost reduction after primary operation, and received anterior release again and finally occipitocervical fusion. All patients were followed up for 15 to 58 (32.0±12.2) months. VAS score was decreased from preoperative 4.2±0.9 to 1.3±0.7 at final follow up and the JOA score was improved from preoperative 11.2±1.2 to 16.9±0.8 at final follow-up. CT scan confirmed that the atlantoaxial or occipitocervical fusion wasgood, and the fusion time was 5 to 9 (6.7±0.6) months. Surgical treatment of os odontoideum complicated with atlantoaxial dislocation can achieve satisfactory results, improve the patient's neurological function and improve the quality of life, however the surgical options needs to be individualized.

Usefulness of a Three-Dimensional-Printed Model in the Treatment of Irreducible Atlantoaxial Dislocation with Transoral Atlantoaxial Reduction Plate.

ObjectiveTo evaluate the usefulness of a 3D‐printed model for transoral atlantoaxial reduction plate (TARP) surgery in the treatment of irreducible atlantoaxial dislocation (IAAD).MethodsA retrospective review was conducted of 23 patients (13 men, 10 women; mean age 58.17 ± 5.27 years) with IAAD who underwent TARP from January 2015 to July 2017. Patients were divided into a 3D group (12 patients) and a non‐3D group (11 patients). A preoperative simulation process was undertaken for the patients in the 3D group, with preselection of the TARP system using a 3D‐printed 1:1 scale model, while only imaging data was used for the non‐3D group. Complications, clinical outcomes (Japanese Orthopaedic Association [JOA] and visual analogue score [VAS]), and image measurements (atlas–dens interval [ADI], cervicomedullary angle [CMA], and clivus‐canal angle [CCA]) were noted preoperatively and at the last follow up.ResultsA total of 23 patients with a follow‐up time of 16.26 ± 4.27 months were included in the present study. The surgery duration, intraoperative blood loss, and fluoroscopy times in the 3D group were found to be shorter than those in non‐3D group, with statistical significance. The surgery duration was 3.29 ± 0.45 h in the 3D group and 4.68 ± 0.90 h in the non‐3D group, and the estimated intraoperative blood loss was 131.67 ± 43.03 mL in the 3D group and 185.45 ± 42.28 mL in the non‐3D group. No patients received blood transfusions. The intraoperative fluoroscopy times were 5.67 ± 0.89 in the 3D group and 7.91 ± 1.45 in the non‐3D group. Preoperatively and at last follow up, JOA and VAS scores and ADI, CCA, and CMA were improved significantly within the two groups. However, no statistical difference was observed between the two groups. However, surgical site infection occurred in 1 patient in the 3D group, who underwent an emergency revision operation of the removal of TARP device and posterior occipitocervical fixation; the patient recovered 2 weeks after the surgery. In 2 patients in the traditional group, a mistake occurred in the placement of screws, with no neurological symptoms related to the misplacement.ConclusionPreoperative surgical simulation using a 3D‐printed real‐size model is an intuitive and effective aid for TARP surgery for treating IAAD. The 3D‐printed biomodel precisely replicated patient‐specific anatomy for use in complicated craniovertebral junction surgery. The information was more useful than that available with 3D reconstructed images.

Cervical spine instability and canal stenosis caused by rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease that impacts on weakening ligaments, synovial arthritis and cartilage damage. The effect that can occur is instability and neural compression in the upper and sub-axial cervical. The prevalence of atlantoaxial instability (AAI) is around 40-80% among rheumatoid patients, but it is interesting to examine the clinical symptoms that are not so visible despite radiological instability confirmed on the cervical spine. However, once the clinical symptoms of myelopathy occur, the mortality rate will increase sharply.&#x0D; We report a case of a 66-years old female who was admitted to our hospital with gait disturbance and weakness of her lower extremities. Radiographic evaluation of the cervical spine showed erosive destruction of the odontoid process of C2, anterior atlantoaxial subluxation, and thickened yellow ligaments from C3 to C7. Surgery was performed by removal of the posterior arch of C1 and laminectomy C3 to C7, posterior occipito-cervical screw fixation from C3 to C7, combined with atlantoaxial transpedicular screw fixation. A sterno sub-occipitomandibular immobilization (SOMI) orthosis was applied for postoperative immobilization for 12 weeks. Improvement of motoric status noted after surgery.

Classification and Surgical Treatment of Developmental Spinal Canal Stenosis at Atlas Level: A 15-Case Study.

A retrospective study. Investigate the diagnosis and surgery strategy for treatment of development spinal canal stenosis (DSSA) at atlas plane based on computerized tography (CT) image characters. The occurrence of spinal canal stenosis in the atlas plane is relatively rare compared with lower cervical. Fifteen patients diagnosed with DSSA were included from 2014 to 2018. They are divided into four subgroups based on the character of CT images: group I (small size atlas), group II (hypertrophy of posterior arch of the atlas [PAA]), group III (incurved of PAA), and group IV (hypertrophy odontoid). There are type I 7, type II 3, type III 2, and group IV 3 in the 15 cases. All the patients received different surgery procedures respectively: (1) posterior arch osteotomy were performed for group I/III//IV without atlantoaxial dislocation, (2) posterior arch resect and replantation were performed for group II, (3) occipital cervical fixation and fusion were added to the patients with associated atlantoaxial dislocation (AAD), (4) a new method of odontoid reduce and atlantoaxial fixation by transoral approach were performed for group IV with associated AAD. All cases underwent surgery successfully which included posterior occipitocervical fixation (OCF) + posterior arch resection (PAR) eight cases, PAR four cases, posterior arch remodeling and re-implantation (PARR) two cases, and Dens remodeling + trans-oral anterior reduction and plate fixation (DR+TARP) one case without severe complications. All patients show different improvement in the symptoms. Japanese orthopaedic association score improved from 9.2 to 14.7 in 1 year follow-up. DSSA could be easily diagnosed and divided into four subgroups according to the character of CT image, corresponding surgery strategy could receive a fine clinical result.Level of Evidence: 4.

Rod and Screw Fixation for Cranio-Cervical Instability

Background Data: Atlanto-occipital dislocation is a rare and fatal condition. Pain, limitation of movements, and weakness, were the main complaints of patients with upper cervical lesions. Internal fixation and fusion was indicated in all patients of Atlanto occipital dislocation with deficits. CT scan is the imaging modality of choice for evaluation. Objective: To evaluate the efficacy and safety of rod and screw fixation in cranio-cervical instability. Study Design: Retrospective study reviewed all patient treated by rod and screw fixation, they were 12 patient operated for atlanto-occipital instability from April 2013 to April 2016 in Alazher University Hospital Damietta. Pre and postoperative data collection and analysis of the outcome were completed based on the Frankel classification and grading. Patients and Methods: We operated 12 patients, 10 with traumatic and 2 with pathologically diagnosed Atlanto occipital instability. From April 2013 to April 2016. All patients presented with neck pain, limitation of neck movement, and neurological deficits. The patients were investigated by standard plain X ray to the cervical spine, CT scan and MRI of the cervical spine pre-operatively, and they operated thorough posterior Cranio-cervical fixation. These patients followed post-operatively clinically for improving neural functions and radiologically for alignment, stability, fusion and efficacy of hard ware fixation. Results: The mean age of the studied cases was 42.1 years, trauma was the cause of instability in 10 patients, and 2 patients one with rheumatoid arthritis and one with neoplastic lesion. The mean follows up period is 14.7 months. We used screw rod system in posterior craniocervical fixation with iliac bone graft without operative or post-operative complications. All our patients were improved neurologically post-operatively and no hardware failure during the follow up period. Conclusion: Craniocervical instability was rare condition, with miss diagnosis and may be fatal condition. Posterior occipitocervical fixation when indicated can be done by various techniques. The screw rod system was the most upgraded used technique with immediate rigid fixation. Surgery in this area was possible with confident results.

Os odontoideum: diagnosis and role of imaging.

To elucidate the imaging manifestations of os odontoideum, establish the diagnosis and guide surgical therapy. Clinical and imaging data, including X-ray, CT and MR of 24 patients with os odontoideum, were retrieved and reviewed retrospectively. Os odontoideum with intact cortex was divided into round, conical and blunt tooth types. Four cases of orthotopic and 20 cases of dystopic os odontoideum were included. There was anterior displacement of the base of the dens in six cases, posterior displacement in nine cases and no displacement in nine cases. A widening of anterior atlanto-axial space was shown in 14 patients with varying degrees. Thickening of the soft tissue posterior to the dens was observed in 19 patients, spinal canal stenosis in 21 patients, cervical myelopathy in 10 patients and craniocervical junction malformation in 9 patients. Posterior C1-C2 pedicle screw fixation and fusion was performed in 12 patients and 4 patients underwent posterior occipito-cervical fixation and fusion. Radiographically, os odontoideum is defined as an independent ossicle of variable size with smooth circumferential cortical margins separated from the axis. Imaging can be used to assess atlanto-axial instability, associated normal or abnormal anatomical structures and guide surgical therapy.

Injury to upper cervical spine treated by posterior internal fixation without bone graft fusion

Objective To investigate the clinical efficacy of treating injury to the upper cervical spine with posterior internal fixation without bone graft fusion. Methods Included in this retrospective study were 35 patients with upper cervical injury who had been treated at Department of Orthopedics, The Second Affiliated Hospital to Soochow University from June 2010 to August 2017. They were 21 males and 14 females with an average age of 44.1 years (from 26 to 56 years). They were all treated firstly by posterior occipitocervical internal fixation or internal fixation with atlantoaxial pedicle screws without bone graft fusion. The internal fixation was then removed after a solid bone union was confirmed by X-ray. The scores of Japanese Orthopedic Association (JOA), visual analogue scale (VAS), Neck disability index (NDI) and neck stiffness were used to evaluate the functional recovery of the upper cervical spine. We also observed the rotational range of the upper cervical spine using functional CT scan of C1-C2. Results All the pedicle screws were successfully implanted after satisfactory intraoperative reduction, leading to no injury to the vertebral artery or spinal cord. All patients were followed up for an average of 18.1 months (from 7 to 28 months). At preoperation, post-implantation and final follow-up, the JOA scores were 6.5±1.4, 7.7±1.5 and 16.1±0.8 points, the VAS scores 6.1±1.6, 2.8±0.8 and 1.1±0.9 points, and the NDI scores 37.9±2.6, 20.3±3.8 and 3.7±1.7 points, showing significant improvements after internal fixation and after removal of internal fixation (P<0.05). Serious neck stiffness was observed in none of the 35 patients, mild neck stiffness in 12 patients and freedom from neck stiffness in 23 patients. The postoperative radiological analysis revealed fine fracture reduction and bony union in all. After 6 to 12 months the rotation of upper cervical spine was obviously improved and the left-to-right range of rotation of C1-C2 was 35.4°±2.6° as revealed by functional CT scan. Conclusion For the middle aged and young patients with new injury to the upper cervical spine, the posterior occipitocervical internal fixation or internal fixation with atlantoaxial pedicle screws can be performed without bone graft fusion at the first stage and removal of internal fixation can be done at the second stage so that the atlantoaxial rotation can be preserved to ensure satisfactory clinical efficacy while bone union can be also ensured and pain reduced. Key words: Cervical spine; Wounds and injuries; Bone nails; Posterior fixation; Non-fusion

Rigid Internal Fixation for Traumatic Cranio-Cervical Dissociation in Infants and Young Children.

Retrospective review. Evaluate radiographic and clinical outcomes for infants and children, who underwent rigid occipito-cervical fixation for traumatic craniocervical dissociation (tCCD). Traumatic craniocervical dissociation is devastating. Children are at high risk but make up a large number of survivors. Non-rigid fixation has traditionally been favored over screw and rod constructs due to inherent challenges involved with instrumenting the pediatric craniocervical junction. Therefore, outcomes for rigid occipito-cervical instrumentation in infants and young children with tCCD remain uncertain. Retrospective review of children who survived tCCD between 2006 and 2016 and underwent rigid occipito-cervical fixation. Fifteen children, from 8 months to 8 years old (mean, 3.8 yr), were either a passenger (n = 11) or a pedestrian (n = 4) in a motor vehicle accident. Seven patients had weakness: five with quadriplegia, one with hemiparesis, and one with bilateral upper extremity paresis. Ten patients had concurrent C1-2 instability. At last follow-up, four patients had improved motor function: one with bilateral upper extremity paresis and one with hemiparesis regained full strength, one with quadriplegia regained function on one side while another regained function in bilateral upper extremities. All underwent rigid posterior occipito-cervical fixation, with two patients requiring additional anterior and posterior fixation at non-contiguous levels. Fourteen patients were stable on flexion-extension x-rays at a mean follow-up of 31 months (9-1 yr or longer, 7-2 yr or longer). There were no cases of deformity, growth disturbance, or subaxial instability. Children who survive tCCD may regain function after stabilization. Rigid internal rod and screw fixation in infants and young children safely provided long-term stability. We advocate using C2 translaminar screws to exploit the favorable anatomy of pediatric lamina to minimize the risks of occipitocervical (OC) instrumentation. 4.

Imaging measurement and clinical significance of occipitocervical angle in healthy people at different ages

To measure imaging data of occipitocervical angle in healthy people at different ages by X-ray. One hundred and fifty asymptomatic volunteers(75 males and 75 females) aged from 20 and 70 years old with an average of(44.83±13.88) years old were divided into 5 groups according to different ages(20 to 29 years old, 30 to 39 years old, 40 to 49 years old, 50 to 59 years old and 60 to 70 years old), and 30 people in each group. All people underwent lateral radiography of neck on neutral position. McGregor line (the lowest connection line between upper margin of hard palate and occipital scales of plating), occipitocervical angle(OCA) formed by edge of C2 vertebral body, takami's occipitocervical angle formed between connection line of posterior marginal of C2 vertebral body and parallel lines of hard palate were collected. The data were performed statistical analysis according to gender and different ages, and analyzed correlation between OCA and TOCA. OCA of 75 males at different ages were (14.71±3.09)° and(14.22±4.27)° in 75 females. TOCA of 75 males at different ages were (90.50±4.63)° and (90.57±6.67) ° in 75 females. There were no statistical difference in OCA and TOCA in people at different ages(P<0.05). There were no significant meaning among 5 groups at different ages in OCA and TOCA(P>0.05). The relation analysis results showed positive correlation between OCA and TOCA(r=0.454, P<0.01). The paper provided normal values for occipitocervical angle in population of southwestern China between 20 and 70 years old, and results may be useful for posterior occipitocervical fixation and fusion.

Posterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty for metastatic involvement of the axis

BackgroundMetastases to the upper cervical spine were rarely reported in the literature. However, metastases to this area may cause spinal instability and cord compression, which in turn can result in respiratory failure and neurological dysfunction. The present study investigated the efficacy and safety of posterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty for this disease.MethodsThis was a retrospective study that included 10 patients with metastatic involvement of the axis from March 2002 to May 2014. All cases presented with occipitocervical pain: 5 patients with compressive myelopathy and 6 patients with radiculopathy. Japanese Orthopedic Association (JOA) scores and Visual Analogue Scale (VAS) were used to evaluate the improvement of neurological function and pain intensity, respectively.ResultsAll patients underwent posterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty. The VAS scores and JOA scores both improved postoperatively, from 8.2 ± 0.4 to 2.3 ± 0.2 and from 10.1 ± 2.2 to 14.2 ± 2.9, respectively. Additionally, the improvement rate of JOA was 52.4 ± 1.8%. The mean overall survival was 12.8 months. The median survival time was 7 months. The 6-month and 12-month survival rates were 70% and 40%, respectively. The mean duration of operation was 182 min and blood loss was 450 mL. The mean volume of bone cement injected was 4.0 mL. The cement extravasation was observed in only 1 patient without clinical symptoms. One patient developed tumour recurrence and died 1 month later.ConclusionsPosterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty was a safe and valuable palliative method with relatively less invasion to treat metastatic involvement of the axis.

Pedicle Screw Combined With Lateral Mass Screw Fixation in the Treatment of Basilar Invagination and Congenital C2-C3 Fusion.

Clinical evaluation of a surgical fixation technique featuring combined use of pedicle screw and lateral mass screw (LMS). Introduction of a novel technique for the treatment of congenital C2-C3 fusion and basilar invagination (BI). Posterior occipitocervical fixation using C2 pedicle screw was widely used for BI. However, in cases where BI is concurrent with congenital C2-C3 fusion, the C2 pedicles tend to be thinner than that in normal population and hence more likely to fail. We prompted to tackle the issue by combining the pedicle screw with the additional use of LMS in attempt to strengthen the fixation. Twenty-five patients who underwent combined pedicle screw with LMS fixation were retrospectively studied. The instrument position, fusion status, and complications were analyzed. None had spinal cord or vertebral artery injury. The average follow-up time was 20 months. Solid fusion was achieved in 23 patients (92%) as detected radiologically. Two cases suffered from recurred BI and instrument failure but eventually achieved solid fusion between the occiput and C2 was after revision. Among all 25 patients, 4 suffered from complications including instruments failure, cerebrospinal fluid leakage, and intracranial infection. The clinical outcome indicates that the technique is reliable for the treatment of BI with congenital C2-C3 fusion.

Stabilization of the Craniovertebral Junction with Clivus Plate Constructs: Biomechanical Comparison with Conventional Technique

Ventral defect caused by resection of the lesions involving the upper cervical spine commonly has been reconstructed with a fabricated mesh cage. Recently, a clival screw and plate fitted to the osseous anatomy of the craniovertebral junction was developed for this pathologic status. To evaluate the stability a clivus plate system fixation (CPSF) for the craniovertebral junction and compare it with a conventional fashioned mesh cage fixation (FMCF). Seven human fresh cadaveric specimens (occiput [Oc], atlas [C1], axis [C2], third cervical vertebra [C3], fourth cervical vertebra [C4]) were tested with intact and destabilization-reconstruction conditions. FMCF and CPSF were applied randomly to the clivus to the C3 segment combined with posterior occipitocervical fixation applied from the occiput to C4 segment, respectively. Specimens were subjected to a pure moment of 1.5 Nm in flexion, extension, lateral bending, and axial rotation, respectively. The range of motion (ROM) and neutral zone (NZ) from the occiput to C3 were calculated and compared between two anterior fixations. Motions were reduced significantly in all directions following FMCF and CPSF fixations when compared with the intact. The CPSF resulted in smaller ROM in lateral bending (0.3°vs. 0.6°, P= 0.015), axial rotation (0.6° vs. 1.2°, P=0.023) and flexion (0.1° vs. 0.3°, P= 0.019), but similar ROM in extension (0.2° vs. 0.4°, P= 0.273) when compared with the FMCF. NZs with the CPSF were 0.1° in flexion-extension, 0.1° in lateral bending and 0.2° in axial rotation, respectively, and similar to NZs with the FMCF. The clivus plate system fixation is biomechanically superior to the conventional fashioned mesh cage fixation in flexion, lateral bending and axial rotation, but equavalent in extension.

Treatment of Basilar Invagination With Klippel-Feil Syndrome: Atlantoaxial Joint Distraction and Fixation With Transoral Atlantoaxial Reduction Plate.

Klippel-Feil syndrome (KFS) is characterized by congenital vertebral fusion of the cervical spine and a wide spectrum of associated anomalies. In patients with KFS with basilar invagination (BI), compression of the brainstem and upper cervical cord results in neurological deficits, and decompression and occipitocervical reconstruction are required. The highly varied anatomy of KFS makes a posterior occipitocervical fixation strategy challenging. For these patients, the transoral atlantoaxial reduction plate (TARP) operation is an optimal option to perform a direct anterior fixation to achieve stabilization. To evaluate the effectiveness of TARP internal fixation for the treatment of BI with KFS. Ten consecutive patients with BI and KFS who underwent TARP reduction and fixation from 2010 to 2012 were reviewed. Clinical assessment and image measurements were performed preoperatively and at the most recent follow-up. Nine patients (9/10) were followed for an average of 31.44 months. Symptoms were alleviated in 9 of 9 patients (100.00%). The odontoid process was ideally corrected with the TARP system. The mean clivus canal angle improved from 124° preoperatively to 152° postoperatively. The average preoperative and postoperative Japanese Orthopedic Association scores were 10.56 (n = 9) and 14.67 (n = 9), respectively, indicating 63.82% improvement. There was bony bridge catenation on the computed tomography scans and no evidence of hardware failure at 6 months. The TARP operation is effective and safe for treating patients with BI with KFS. The midterm clinical results were satisfactory.