Posterior C1-C2 Arthrodesis Research Articles

Outcomes following anterior odontoid screw versus posterior arthrodesis for odontoid fractures: a systematic review and meta-analysis.

Odontoid fractures can be managed surgically when indicated. The most common approaches are anterior dens screw (ADS) fixation and posterior C1-C2 arthrodesis (PA). Each approach has theoretical advantages, but the optimal surgical approach remains controversial. The goal in this study was to systematically review the literature and synthesize outcomes including fusion rates, technical failures, reoperation, and 30-day mortality associated with ADS versus PA for odontoid fractures. A systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines by searching the PubMed, EMBASE, and Cochrane databases. A random-effects meta-analysis was performed and the I2 statistic was used to assess heterogeneity. In total, 22 studies comprising 963 patients (ADS 527, PA 436) were included. The average age of the patients ranged from 28 to 81.2 years across the included studies. The majority of the odontoid fractures were type II based on the Anderson-D'Alonzo classification. The ADS group was associated with statistically significantly lower odds to achieve bony fusion at last follow-up compared to the PA group (ADS 84.1%; PA 92.3%; OR 0.46; 95% CI 0.23-0.91; I2 42.6%). The ADS group was associated with statistically significantly higher odds of reoperation compared to the PA group (ADS 12.4%; PA 5.2%; OR 2.56; 95% CI 1.50-4.35; I2 0%). The rates of technical failure (ADS 2.3%; PA 1.1%; OR 1.11; 95% CI 0.52-2.37; I2 0%) and all-cause mortality (ADS 6%; PA 4.8%; OR 1.35; 95% CI 0.67-2.74; I2 0%) were similar between the two groups. In the subgroup analysis of patients > 60 years old, the ADS was associated with statistically significantly lower odds of fusion compared to the PA group (ADS 72.4%; PA 89.9%; OR 0.24; 95% CI 0.06-0.91; I2 58.7%). ADS fixation is associated with statistically significantly lower odds of fusion at last follow-up and higher odds of reoperation compared to PA. No differences were identified in the rates of technical failure and all-cause mortality. Patients receiving ADS fixation at > 60 years old had significantly higher and lower odds of reoperation and fusion, respectively, compared to the PA group. PA is preferred to ADS fixation for odontoid fractures, with a stronger effect size for patients > 60 years old.

O-Arm Assisted Anterior Odontoid Screw Fixation in Type II and Rostral Type III Odontoid Fractures: Single Center Surgical Series of 50 Patients.

Accuracy of screw placement is one of the important factors necessary for adequate union in odontoid fractures with malposition rates as high as 27.2% with standard techniques. To evaluate efficacy of intraoperative O-arm assistance in improving accuracy of anterior odontoid screw placement and clinco-radiological outcome in type II and III odontoid fractures. In this retrospective study, surgery consisted of anterior odontoid screw fixation under intraoperative O-arm assistance over 5 years. Demographical, clinical, radiological, operative details and postoperative events were retrieved from hospital database and evaluated for fusion and surgical outcome. 50 patients (Mean age 34.6 years, SD 14.10, range: 7-70 years; 44 males and 6 females) with Type II and Type III odontoid fracture underwent O-arm assisted anterior screw placement. The mean interval between injury and surgery was 12 days (range 1-65 days). Mean operating time was 132.2 min ± SD 33.56 with average blood loss of 93 ml. ±SD 61.46. With our technique, accurate screw placement was achieved in 100% patients. At the mean follow-up of 26.4 month (SD13.75), overall acceptable fusion rate was 97.8% with non-union in 2.2% patients. Morbidity occurred in two patients; one patient developed fixation failure while other patient had nonunion which was managed with posterior C1-C2 arthrodesis. We had surgical mortality in one patient due to SAH. So overall our procedure was successful in 94% patients and among patients whose follow-up was available, acceptable fusion rates of 97.8% were achieved. We conclude that use of intraoperative three-dimensional imaging using O-arm for anterior odontoid screw fixation improves accuracy and leads to improved radiological and clinical outcomes. It further enables us to extend the indications of odontoid screw fixation to selected complex Type II and rostral Type III odontoid fractures.

Upper Cervical Spine Injuries: Profile and Management of 120 Cases.

To identify the profile and management of patients with upper cervical spine injury. Retrospective cohort study of patients with upper cervical spine injuries managed at Hospital da Restauração between 2014 and 2020. It presents the profile of 145 injuries recorded by location and classification among the 120 patients, and the management performed. Men are more affected than women, almost half of the patients (42.5%) were aged 16 to 29 years. Neurological deficit was present in 18 cases (15%). Twenty cases presented injury involving the level C1. Most injuries (109 [90.8%]) occurred at the C2 level, the most frequent of which were as follows: isolated type II odontoid fracture (29.2%), miscellaneous fracture of C2 (20%), and isolated hangman's fracture (13.3%). The most used management in type II odontoid fracture was C1-C2 posterior arthrodesis (17/42) followed by odontoid osteosynthesis (12/42). Regarding isolated hangman's fracture, conservative management was performed in 37.5% (6/16), and the technical approach most performed was anterior C2-C3 discectomy and interbody fusion (5/16). Upper cervical spine injury has a higher prevalence in young men and is most often caused by traffic accidents. The main level affected is C2, and type II odontoid fracture is the most frequent subtype. C1 injury is related to conservative treatment, while C2 or combined C1-C2 injury is related to surgical approach. The management of these injuries is mainly performed with surgical treatment, with C1-C2 posterior arthrodesis and anterior odontoid osteosynthesis representing most of the approaches.

Intraoperative Doppler ultrasound as a means of preventing vertebral artery injury during Goel and Harms C1-C2 posterior arthrodesis: technical note.

Vertebral artery injury (VAI) is a potential catastrophic complication of Goel and Harms C1-C2 posterior arthrodesis. Meticulous study of preoperative spinal CT angiography together with neuronavigation plays a fundamental role in avoiding VAI. Doppler ultrasonography may be an additional intraoperative tool, providing real-time identification of the vertebral artery (VA) and thus helping its preservation.Thirty-three consecutive patients with unstable odontoid fractures underwent Goel and Harms C1-C2 posterior arthrodesis. Surgery was performed with the aid of lateral fluoroscopic control in 16 cases (control group) that was supplemented by Doppler ultrasonography in 17 cases (Doppler group). Two patients in each group had a C1 ponticulus posticus. In the Doppler group, Doppler probing was performed during lateral subperiosteal muscle dissection, stepwise drilling, and tapping. Blood flow velocity in the V3 segment of the VA was recorded before and after posterior arthrodesis. All patients had a 12-month outpatient follow-up, and outcome was assessed using the Smiley-Webster Pain Scale. Neither VAI nor postoperative neurological impairments were observed in the Doppler group. In the control group, VAIs occurred in the 2 patients with C1 ponticulus posticus. In the Doppler group, 1 patient needed intra- and postoperative blood transfusions, and no difference in terms of Doppler signal or VA blood flow velocity was detected before and after C1-C2 posterior arthrodesis. In the control group, 3 patients needed intra- and postoperative blood transfusions.Useful in supporting fluoroscopy-assisted procedures, intraoperative Doppler may play a significant role even during surgeries in which neuronavigation is used, reducing the chance of a mismatch between the view on the neuronavigation screen and the actual course of the VA in the operative field and supplying the additional data of blood flow velocity.

Functional Outcome of Elderly Patients Treated for Odontoid Fracture: A Multicenter Study.

Retrospective multicenter study. Analysis of impact of conservative and surgical treatments on functional outcome of geriatric odontoid fractures. Treatment of odontoid fractures in aged population is still debatable. One hundred fourty-seven consecutive odontoid fractures in elderly patients were classified according to Anderson-D'Alonzo and Roy-Camille classifications. Philadelphia type collar was always positioned and kept as a treatment whenever acceptable. Halo-vest, anterior screw fixation, C1-C2 posterior arthrodesis, and occipito-cervical fixation were the other treatments adopted. Conservative or surgical treatment strategy was more significantly influenced by antero-posterior displacement (< or >5 mm) and by surgeon decision. On admission ASA, modified Rankin scale (mRS-pre) and Charlson Comorbidity Index (CCI) were assessed. Modified Rankin scale (mRS-post), Neck Disability Index (NDI), and Smiley Webster Pain Scale (SWPS) were administered 12 to 15 months after treatment to estimate functional outcome in terms of general disability, neck-related disability, and ability to return to work/former activity. Risk of treatment crossover was calculated considering factors affecting outcome. Fracture healing process in terms of fusion-stability, no fusion-stability, no fusion-no stability was evaluated at 12 months through a cervical computed tomography (CT) scan. Dynamic cervical spine x-rays were obtained whether necessary. No fusion-stability was considered an adequate treatment goal in our geriatric population. Chi square/Fisher exact test and logistic regression were performed for statistical anal. Overall 67 patients were treated conservatively whereas 80 underwent surgery. Collar was adopted in 45 patients, while anterior odontoid fixation and C1-C2 posterior arthrodesis were preferred for 30 patients each. 79.8% of patients showed good outcomes according to NDI. No significant differences were observed between patients of 65 to 79 years and more than or equal to 80 years (P = 0.81). CCI greatly correlated with mRS-post, with higher indexes in 68.8% of cases characterized by good outcomes (P = 0.05). mRS-pre correlated with NDI (P < 0.000001) and mRS-post (P = 0.04). CCI, mRS-pre, and surgery were associated with worse NDI, while both C1-C2 posterior arthrodesis and occipito-cervical stabilization were associated with worse mRS-post, respectively in 40% and 30% of cases. Younger patients had a higher risk of treatment crossover. mRS-pre and CCI provided two independent predictive values respectively for functional outcome and post-treatment disability. Compared with conservative immobilizations, surgery revealed no advantages in the elderly in terms of functional outcome. 3.

Safety and Efficacy of Posterior Atlanto-Axial Stabilization Using Intraoperative Navigation System with Preoperative Computed Tomographic Scan

Surgical approaches for posterior C1-C2 arthrodesis, such as C1-C2 transarticular and C1-C2 screw stabilization, are known to be demanding because of the anatomic close proximity of cervical vertebrae to neurovascular structures. Currently, navigation by fluoroscopy or intraoperative computed tomography (ICT) is the standard practice. However, fluoroscopy has various limitations, and ICT is time consuming and not available in many centers; furthermore, both diagnostic tools lead to exposure of the operating room staff to radiation exposure. We evaluate the safety, efficacy, and facility of a navigation system using only preoperative cervical computed tomography and computed tomographic angiography (CT/CTA), to prevent the risk of neurovascular damage in atlantoaxial stabilization. The authors report a series of 21 patients who underwent posterior upper cervical spine fixation using a navigation system with intraoperative single-level vertebral registration on preoperative cervical CT/CTA (software BrainLab IPlan Spine 3.0). Intraoperative and postoperative comparative analysis was performed to verify the correspondence between the virtual anatomic position of the surgical instruments and screws represented on the neuronavigator, and the actual positions verified intraoperatively and on postoperative CT. Thirteen patients underwent C1-C2 arthrodesis with a Harms construct, 1 patient with transarticular screw fixation and 4 patients with occipitocervical stabilization. Three patients underwent C1-C2-C3 stabilization with C1 hooks, C2-C3 screws, and rod construct. On postoperative CT, the position of all screws appeared satisfactory. No neurovascular damage occurred in any patients. The use of a neuronavigation system, based on preoperative acquired cervical CT and intraoperative single-vertebra registration, may provide a valuable support for the improvement of the surgical accuracy of posterior C1-C2 screw fixation.

Fusion rates for odontoid fractures after treatment by anterior odontoid screw versus posterior C1-C2 arthrodesis: a meta-analysis.

For odontoid fractures, surgical treatment approaches including anterior odontoid screw fixation approach and the posterior C1-C2 arthrodesis approach are generally adopted in practice. However, the choice of different surgical procedures remains controversial. In addition to surgical technique, the fusion rate is an important factor contributing to the clinical efficacy. Therefore, this study was aimed to investigate the discrepancy in fusion rate between these two surgical approaches through synthesizing the currently available evidence on the topic. A computerized search of Ovid, Medline, Embase, and the Cochrane library up to December 2017 for literature on the complication rate during odontoid fracture treatment was conducted. Risk ratio (RR) with its 95% confidence interval (CI) was pooled to assess fusion rates after surgical treatments, including anterior odontoid screw fixation approach or posterior C1-2 arthrodesis procedure, for patients with odontoid fractures. Thirteen studies were enrolled in the meta-analysis. Results show that no significant difference was found in the overall fusion rate (RR = 0.96, 95% CI 0.90-1.01). There was no significant heterogeneity among the studies (p value = 0.60). As to age- and economic-level subgroups, there was no statistical evidence to suggest an association of the patient age and economy development level with the choice of surgical approach. However, it is shown that better fusion rates of patients (≥ 60years) in developed countries received a better fusion rates after posterior fixation compared with anterior group using the fixed-effect model (RR = 0.88, 95% CI 0.79-0.98). Elderly patients (≥ 60years) underwent posterior C1-2 arthrodesis fixation shows higher fusion rates in developed countries comparing with patients who underwent anterior odontoid screw fixation. Overall, there is no significant discrepancy between these two surgical approaches. However, the conclusion should be verified by further study enrolling larger sample size.

Successful Treatment of Severe Occipitocervical Pain from C1-C2 Osteoarthritis Using a Modified Harms Technique

Introduction C1-C2 fusion with instrumentation is an established treatment for C1-C2 instability due to trauma or inflammatory disease. C1-C2 fusion for debilitating occipitocervical pain secondary to C1-C2 osteoarthritis has been reported in a small number of patients. Here we report the successful treatment of three patients that underwent C1-C2 instrumented fusion using a modified Harm's technique for medically refractory occipitocervical pain. Materials and Methods Between August 2012 and July 2015, three consecutive patients with debilitating, unilateral occipitocervical pain and radiographic C1–2 osteoarthritis, underwent posterior instrumented C1-C2 arthrodesis using bilateral polyaxial C1 lateral mass and C2 pedicle screw and rod constructs (modified Harms technique). All three patients failed preoperative conservative treatment including therapy, medical management and interventional pain management including facet joint injections. In all three patients, the source of occipitocervical pain was confirmed preoperatively with direct C1-C2 joint injection using 0.5ml of a mixture of 2% lidocaine/0.5% Marcaine/10mg kenalog. All three patients had immediate but temporary relief of their occipitocervical pain from the diagnostic C1-C2 joint injection. Preoperative CT scan confirmed the presence of C1-C2 osteoarthritis on the symptomatic side. Outcome measures include pre and postoperative VAS, patient reported resolution of pain, hospital LOS, EBL and complications. Results Each of the three patients surgically treated had complete resolution (100%) of their preoperative occipitocervical pain beginning immediately after instrumented posterior fusion of C1–2. Average VAS improved from 8.3 preoperatively to 0.0 postoperative for the cohort. Average follow up is 33 months. Average age for the group at the time of surgery was 75 years old and the M:F ratio is 1:2. Hospital LOS was 1 day for each patient. EBL was 45ml on average with a range of 15ml - 75ml. There were no postoperative complications. Conclusions Instrumented posterior C1-C2 fusion, using a modified Harms technique, is a safe and effective treatment for refractory occipitocervical pain secondary to C1-C2 osteoarthritis. The source of pain should be confirmed preoperatively with both CT scan and diagnostic joint injection.

Anterior Retropharyngeal Reduction and Sequential Posterior Fusion for Atlantoaxial Rotatory Fixation With Locked C1-C2 Lateral Facet.

Retrospective case series. To introduce a new type of atlantoaxial rotatory fixation (AARF) with a locked C1-C2 lateral facet and evaluate its therapeutic strategy. AARF presenting with torticollis and limited neck motion is commonly seen in teenagers. Fielding and Hawkins' classification is generally applied to AARF. Although conservative treatment is effective for acute AARF, it is often unsuccessful for chronic AARF, which ultimately requires surgery. We introduce a new type of chronic AARF with a locked C1-C2 lateral facet that does not fit into Fielding and Hawkins' classification and describe the appropriate treatment. Eight patients who had chronic AARF with a unilaterally locked C1-C2 lateral facet were referred to our clinic. Reduction had failed after traction for 3 to 4 weeks. After open release and reduction using the anterior retropharyngeal approach, we applied posterior C1-C2 transpedicular screw fixation with an autologous iliac bone graft for stage I or II. The anterior retropharyngeal approach provided direct access to the C1-C2 locked lateral facet. The patient in an overall poor condition (stage II) underwent delayed posterior C1-C2 arthrodesis. The others (stage I) underwent immediate posterior C1-C2 arthrodesis. All patients were followed up for an average of 14.8 months (5-37 mo). Three-dimensional computed tomography revealed C1-C-2 arthrodesis bone graft fusion after an average of 3.1 months (2-4 mo). There was no recurrence of symptoms and no dislocations or internal fixation device loosening or breakage. AARF with a locked C1-C2 lateral facet is a new type of AARF that cannot be classified using Fielding and Hawkins' classification. The anterior retropharyngeal approach for the release and reduction of AARF, followed by posterior C1-C2 arthrodesis is an effective therapeutic strategy for AARF with a locked C1-C2 lateral facet. 4.

Myoarchitectonic advancement of the C2 spinous process for C1-C2 posterior fusion: A novel technique.

Study Design:Retrospective descriptive study of an innovative surgical technique.Objective:To assess the feasibility of using a large C2 spinous process as a vascularized bone graft donor with muscles attached to it in C1-C2 posterior fusion with evaluation of post operative fusion and pain in these cases.Summary of Background Data:C1-C2 posterior fusion essentially requires a bone graft and for this a separate incision is needed at the donor site with its associated morbidity. The procedure also entails detachment of muscles attached to the C2 spinous process. Due to the detachment of these muscles with important functions, postoperative nuchal pain is common in these patients. We developed a novel technique of harvesting the vascularized C2 spinous process as a bone graft to minimize the above-mentioned complications.Materials and Methods:Five patients with atlanto-axial dislocation due to various pathologies underwent C1-C2 posterior arthrodesis with the present technique. They were followed up for 6 to 18 months and were evaluated for feasibility of procedure, post operative fusion and post operative complications, especially pain.Results:The procedure was accomplished successfully in all patients without any perioperative complications. All patients were pain free 3 months after surgery—mean Visual Analogue Scale (VAS) was 0.4. Fusion (confirmed by plain radiography in three and by CT scan in two patients) was achieved in all five patients (100%).Conclusion:Myoarchitectonic advancement of C2 spinous process is a novel technique of C1-C2 posterior fusion in which a local vascularized bone graft is used avoiding donor site morbidity and at the same time preservation of dynamic function of muscles attached reduces the post operative pain.

Treatment of Dens Fractures with Posterior Transarticular Fixation.

Treatment of unstable dens fractures with posterior transarticular C1-C2 arthrodesis provides a biomechanically stable construct, even when poor bone quality is present, and a low rate of complications even in elderly patients; however, when this method of fixation is performed, cervical spine rotation is substantially reduced as compared with that associated with alternative fixation techniques. Exact positioning of the patient and use of image intensifiers are mandatory to obtain appropriate anteroposterior and lateral views of C1 and C2. Use the modified technique of Magerl and Seemann, as it allows a less extensive approach to C1 and C2, and the drill can enter through two incisions at the level of T1. Use smooth 2.0-mm Kirschner wires to prepare the canal for the screws, and subsequently replace them with 3.0-mm self-tapping screws. Perform a modified Gallie fusion, in addition to the transarticular screw fixation, to increase stability and osseous fusion between C1 and C2. Perform meticulous closure of the wound to avoid wound-healing complications. In our original study, we treated twenty-five patients with posterior transarticular fixation.IndicationsContraindicationsPitfalls & Challenges.

C1-C2 stabilization by harms arthrodesis: Indications, technique, complications and outcomes in a prospective 26-case series

IntroductionC1-C2 arthrodesis is a surgical challenge due to the proximity of neurovascular structures (vertebral arteries and spinal cord) and the wide range of motion of the joint, hampering bone fusion. A variety of techniques have been successively recommended to reduce anatomic risk and improve results in terms of biomechanical stability and fusion rates. Recently, Harms described a new technique using polyaxial screws in the C1 lateral masses and C2 pedicles. Material and methodThe present study reports our experience in a consecutive series of 26 patients operated on by C1-C2 arthrodesis using the Goel and Harms technique, and details technical aspects step by step. Routine systematic immediate postoperative CT and 6-month CT controlled screw positioning and assessed fusion. Follow-up was at least 1 year, except in 2 cases (10 months). ResultsTwenty-six patients with a mean age of 57 years were included. Indications comprised: C2 non-union (n=11), C1-C2 fracture and/or dislocation (n=11), inflammatory pathology (n=2) and tumoral pathology (n=2). The results showed the technique to be reliable (no neurovascular complications and 85% of screws with perfect positioning) and an excellent rate of fusion (100% at 6 months). ConclusionAnatomic and biomechanical considerations, combined with the present clinical and radiological outcomes, indicate that Goel and Harms fusion is to be considered the first-line attitude of choice for posterior C1-C2 arthrodesis. Level of EvidenceLevel IV prospective study.

Functional and Quality-of-Life Outcomes in Geriatric Patients with Type-II Dens Fracture

Dens fractures are relatively common in the elderly. The treatment of Type-II dens fractures remains controversial. The aim of this multicenter prospective cohort study was to compare outcomes (assessed with use of validated clinical measures) and complications of nonsurgical and surgical treatment of Type-II dens fractures in patients sixty-five years of age or older. One hundred and fifty-nine patients with a Type-II dens fracture were enrolled in a multicenter prospective study. Subjects were treated either surgically (n = 101) or nonsurgically (n = 58) as determined by the treatment preferences of the treating physicians and the patients. The subjects were followed at six and twelve months with validated outcome measures, including the Neck Disability Index (NDI) and Short Form-36v2 (SF-36v2). Treatment complications were prospectively recorded. Statistical analysis was performed to compare outcome measures before and after adjustment for confounding variables. The two groups were similar with regard to baseline characteristics. The most common surgical treatment was posterior C1-C2 arthrodesis (eighty of 101, or 79%) while the most common nonsurgical treatment was immobilization with use of a hard collar (forty-seven of fifty-eight, or 81%). The overall mortality rate was 18% over the twelve-month follow-up period. At twelve months, the NDI had increased (worsened) by 14.7 points in the nonsurgical cohort (p < 0.0001) compared with a nonsignificant increase (worsening) of 5.7 points in the surgical group (p = 0.0555). The surgical group had significantly better outcomes as measured by the NDI and SF-36v2 Bodily Pain dimension compared with the nonsurgical group, and these differences persisted after adjustment. There was no difference in the overall rate of complications, but the surgical group had a significantly lower rate of nonunion (5% versus 21% in the nonsurgical group; p = 0.0033). Mortality was higher in the nonsurgical group compared with the surgical group (annual mortality rates of 26% and 14%, respectively; p = 0.059). We demonstrated a significant benefit with surgical treatment of dens fractures as measured by the NDI, a disease-specific functional outcome measure. As a result of the nonrandomized nature of the study, the results are vulnerable to the effects of possible residual confounding. We recommend that elderly patients with a Type-II dens fracture who are healthy enough for general anesthesia be considered for surgical stabilization to improve functional outcome as well as the union and fusion rates.

Management of Chronic Atlantoaxial Rotatory Fixation

Retrospective case series of chronic atlantoaxial rotatory fixation (AARF) treated by a novel closed reduction method (remodeling therapy) and review of the literature. To describe clinical features of chronic AARF and the rationale of the remodeling therapy. Treatment strategy for chronic recurrent AARF remains controversial. Posterior C1-C2 arthrodesis has been widely used for recurrent unstable AARFs after the closed reduction, and a variety of posterior fusion techniques have been advocated. In contrast, several investigators reported a chronic AARF case treated by a simple traction or closed reduction followed by cervical immobilization. Previously, we have found that a deformity of the superior C2 facet joint (C2 facet deformity) on three dimensional computed tomography (3D CT) reconstructions is a risk factor for recurrent subluxation. In addition, the remodeling of this C2 facet deformity by careful closed manipulation followed by halo fixation (remodeling therapy) could prevent the recurrence of subluxation. Twelve children with chronic AARF who sustained torticollis for an average of 4.4 months after the onset were referred to our clinic. The mean age at the initial visit was 7.8 years. All patients underwent the remodeling therapy as reported previously. Radiographic findings and clinical courses were retrospectively reviewed. Treatment methodology, pearls, and pitfalls of the remodeling therapy were discussed with review of the literature. 3D CT images before reduction revealed persistent atlantoaxial subluxation and the C2 facet deformity in the dislocated side in all cases. Follow-up 3D CT scans demonstrated the remodeling of the C2 facet deformity at an average of 2.4 months after successful reduction of subluxation. Neither recurrence of symptoms nor subluxation was observed at a mean follow-up of 42 months in any case. The cervical range of motion was 73.9° at the dislocated and 83.5° at the contra-dislocated side from the midline. Chronic irreducible and recurrent unstable AARF should be initially managed by remodeling therapy using the facet deformity sign as a clinical index, if the C1 and C2 have not been osseously fused.

Minimally invasive anterior transarticular screw fixation and microendoscopic bone graft for atlantoaxial instability

Even though transarticular screw (TAS) fixation has been commonly used for posterior C1-C2 arthrodesis in both traumatic and non-traumatic lesions, anterior TAS fixation C1-2 is a less invasive technique as compared with posterior TAS which produces significant soft tissue injury, and there were few reports on percutaneous anterior TAS fixation and microendoscopic bone graft for atlantoaxial instability. The goals of our study were to describe and evaluate a new technique for anterior TAS fixation of the atlantoaxial joints for traumatic atlantoaxial instability by analyzing radiographic and clinical outcomes. This was a retrospective study of seven consecutive patients with C1-C2 instability due to upper cervical injury treated by a minimally invasive procedure from May 2007 to August 2009. Bilateral anterior TAS were inserted by the percutaneous approach under Iso-C3D fluoroscopic control. The atlantoaxial joint space was prepared for morselized autogenous bone graft under microendoscopy. The data for analysis included time after the injuries, operating time, intraoperative blood loss, X-ray exposure time, clinical results, and complications. Radiographic evaluation included the assessment of atlantoaxial fusion rate and placement of TAS. Bone fusion of the atlantoaxial joints was assessed by flexion extension lateral radiographs and 1-mm thin-slice computed tomography images as radiographic results. Clinical assessment was done by analyzing the recovery state of clinical presentation from the preoperative period to the last follow-up and by evaluating complications. A total of 14 screws were placed correctly. The atlantoaxial solid fusion without screw failure was confirmed by CT scan in seven cases after a mean follow-up of 27.5 months (range 18-45 months). All patients with associated clinical presentation made a recovery without neurologic sequelae. Postoperative dysphagia occurred and disappeared in two cases within 5 days after surgery. There were no other complications during the follow-up period. Percutaneous anterior TAS fixation and microendoscopic bone graft could be an option for achieving C1-C2 stabilization with several potential advantages such as less tissue trauma and better accuracy. Bilateral TAS fixation and morselized autograft affords effective fixation and solid fusion by a minimally invasive approach.

Surgical Treatment of Chronic C1–C2 Dislocation With Absence of Odontoid Process Using C1 Hooks With C2 Pedicle Screws

A case report. OBJECTIVE.: A rare case of chronic C1-C2 dislocation with absence of odontoid process that underwent posterior C1-C2 arthrodesis using C1 hooks and C2 pedicle screws. C1-C2 dislocation is a rare but fatal upper cervical injury. To date, there have been many reports about C1-C2 dislocation of traumatic origin. However, very few C1-C2 dislocation cases of congenital odontoid deformities had been presented. This was particularly the case when the odontoid process was absent. Plain radiograph of his cervical spine revealed a C1-C2 dislocation, and subsequent computed tomographic scan as well as magnetic resonance imaging (MRI) detected absence of odontoid process and cord compression. Upon admission, the patient was placed on skull traction and the weight increased from 3.5 to 5.5 kg. After 10 days of traction, reduction was achieved radiographically and the posterior C1-C2 arthrodesis by C1 hooks with C2 pedicle screws was performed. After surgery, the patient showed significant improvement in gait function despite slightly raised muscle tone in his lower extremities. Four-month postoperative radiographs indicated restoration of C1-C2 alignment and bony fusion. No residual cord compression was present. In clinical evaluation of patients who present with neck pain and limited cervical motion with or without neurologic deficits, C1-C2 dislocation should be considered. If the patient has no history of trauma or infection, congenital C1-C2 deformity, especially odontoid malformation, has to be included as a possible factor. Once the diagnosis is confirmed, posterior C1-C2 arthrodesis may become necessary for stabilizing C1-C2 and preventing it from deterioration or new development of neurologic symptoms.

Atlanto-axial Chronic Rotational Subluxation

Introduction Atlanto-axial rotational subluxation, a relatively common condition in pediatric patients, is normally secondary to traumatic inflammatory processes and is favored by the great degree of cervical mobility in children. If untreated, the condition may become chronic and result in a fixed cervical deformity whose diagnosis and treatment may pose a significant challenge. Only a few series have been published, all of them containing a small number of cases and there is an absence of definite criteria for the diagnosis and treatment of this condition. Clinical cases Three cases are presented of atlanto-axial chronic rotational subluxation treated over a 15-year period. Ages at presentation were 9.7 and 16 year. In all patients, the same protocols, both diagnostic (x-rays, CT-scan and MRi in one case) and therapeutic (gradual halo traction until reduction was confirmed by a CT-scan and halo cast immobilization) were used. In one case full reduction was not achieved and, consequently, a C1-C2 posterior arthrodesis was performed. Results All three patients had a minimum follow-up of 2 years. Patients not subjected to arthrodesis showed a satisfactory clinical situation and normal cervical motion; the remaining patient had slight torticollis with somewhat limited cervical rotation. There have been no relapses. Conclusions Atlanto-axial chronic rotational subluxation is a condition with severe and painful repercussions for the patient and whose management poses serious challenges. In our series, all cases were treated following the same protocol: progressive cranial traction and halo cast immobilization. Complete reduction was achieved, while in the remaining one the reduction achieved was only partial, which made it necessary to perform a C1-C2 posterior arthrodesis. As the literature does not provide hard-and-fast treatment criteria, we suggest possible protocols for action.

Mini-open approach combined with percutaneous transarticular screw fixation for C1?C2 fusion

This paper describes a limited exposure for posterior C1-C2 arthrodesis aided by percutaneous transarticular fixation. The purpose of this study was to report the fusion rate using the aforementioned method. Fifty-seven patients (54 females and three males) with C1-C2 instability due to rheumatoid disease constituted the material of this study. The exposure was restricted to C0-C3 levels. The drilling and insertion of the screws was done through two mini stab wounds. A special sleeve and screwdriver were developed to facilitate this step. An autogenous iliac bone graft was fixed between the decorticated posterior arch of the atlas and the lamina of the axis vertebra. The mean of the atlantodental interval decreased from 8.5 mm (SD 2.3 mm) to 2.6 mm (SD 0.6 mm) at the immediate postoperative periods and reached 2.7 mm (SD 0.7 mm) after a mean follow-up of 30.4 months (SD 5.6 months). Malposition of the screws was observed in two patients and warranted a second operation in one. Fusion was evident in 98% of the cases. Percutaneous insertion of the screws in posterior C1-C2 transarticular fixation reduces the size of the exposure and the surgical trauma to the cervical segments below the fixation.

Os Odontoideum

This case report identifies one identical twin with an os odontoideum after trauma and the other twin with a normal cervical spine and no history of trauma. To highlight the etiology of os odontoideum as posttraumatic as opposed to congenital in nature. The etiology of os odontoideum has been debated since its original description by Giacomini in 1886. Although proponents of the congenital origin are supported by association with various congenital anomalies, including Down's syndrome, Klippel-Feil syndrome, and multiple epiphyseal dysplasia, the majority of reports suggest a posttraumatic etiology. We reviewed the cervical radiographs of an identical twin with transient paresis and significant trauma to her neck as a child after a motor vehicle accident. The radiographs were compared with those of her twin sister, who had no history of trauma. Os odontoideum was identified in one identical twin with a history of trauma. She was treated with a posterior C1-C2 arthrodesis using the Magerel transarticular screw technique supplemented by a modified Gallie's wiring. At a 12-month follow-up, she was asymptomatic and had a solid fusion based on flexion and extension views. This case report of an os odontoideum occurring in one identical twin after a traumatic injury supports the possibility of a posttraumatic, as opposed to congenital, theory of origin.

Use of Halifax interlaminar clamps for posterior C1-C2 arthrodesis.

Eight patients with atlantoaxial instability secondary to trauma or rheumatoid arthritis were treated with posterior C1-C2 arthrodesis using the Halifax interlaminar clamp and autogenous bone graft or methylmethacrylate. Thus far, with an average follow-up of 6 months, satisfactory stability has been achieved with no instrument failure.