Odontoid Screw Research Articles

Anterior cervical spine surgery-associated complications in a retrospective case-control study.

Anterior cervical spine procedures have been associated with satisfactory outcomes. However, the occurrence of troublesome complications, although uncommon, needs to be taken into consideration. The purpose of our study was to assess the actual incidence of anterior cervical spine procedure-associated complications and identify any predisposing factors. A total of 114 patients undergoing anterior cervical procedures over a 6-year period were included in our retrospective, case-control study. The diagnosis was cervical radiculopathy, and/or myelopathy due to degenerative disc disease, cervical spondylosis, or traumatic cervical spine injury. All our participants underwent surgical treatment, and complications were recorded. The most commonly performed procedure (79%) was anterior cervical discectomy and fusion (ACDF). Fourteen patients (12.3%) underwent anterior cervical corpectomy and interbody fusion, seven (6.1%) ACDF with plating, two (1.7%) odontoid screw fixation, and one anterior removal of osteophytes for severe Forestier's disease. Mean follow-up time was 42.5 months (range, 6-78 months). The overall complication rate was 13.2%. Specifically, we encountered adjacent intervertebral disc degeneration in 2.7% of our cases, dysphagia in 1.7%, postoperative soft tissue swelling and hematoma in 1.7%, and dural penetration in 1.7%. Additionally, esophageal perforation was observed in 0.9%, aggravation of preexisting myelopathy in 0.9%, symptomatic recurrent laryngeal nerve palsy in 0.9%, mechanical failure in 0.9%, and superficial wound infection in 0.9%. In the vast majority anterior cervical spine surgery-associated complications are minor, requiring no further intervention. Awareness, early recognition, and appropriate management, are of paramount importance for improving the patients' overall functional outcome.

Biomechanical Comparison of Inter-fragmentary Compression Pressures: Lag Screw versus Herbert Screw for Anterior Odontoid Screw Fixation.

ObjectiveThe purpose of the present study was to compare inter-fragmentary compression pressures after fixation of a simulated type II odontoid fracture with the headless compression Herbert screw and a half threaded cannulated lag screw.MethodsWe compared inter-fragmentary compression pressures between 40- and 45-mm long 4.5-mm Herbert screws (n=8 and n=9, respectively) and 40- and 45-mm long 4.0-mm cannulated lag screws (n=7 and n=10, respectively) after insertion into rigid polyurethane foam test blocks (Sawbones, Vashon, WA, USA). A washer load cell was placed between the two segments of test blocks to measure the compression force. Because the total length of each foam block was 42 mm, the 40-mm screws were embedded in the cancellous foam, while the 45-mm screws penetrated the denser cortical foam at the bottom. This enabled us to compare inter-fragmentary compression pressures as they are affected by the penetration of the apical dens tip by the screws.ResultsThe mean compression pressures of the 40- and 45-mm long cannulated lag screws were 50.48±1.20 N and 53.88±1.02 N, respectively, which was not statistically significant (p=0.0551). The mean compression pressures of the 40-mm long Herbert screw was 52.82±2.17 N, and was not statistically significant compared with the 40-mm long cannulated lag screw (p=0.3679). However, 45-mm Herbert screw had significantly higher mean compression pressure (60.68±2.03 N) than both the 45-mm cannulated lag screw and the 40-mm Herbert screw (p=0.0049 and p=0.0246, respectively).ConclusionOur results showed that inter-fragmentary compression pressures of the Herbert screw were significantly increased when the screw tip penetrated the opposite dens cortical foam. This can support the generally recommended surgical technique that, in order to facilitate maximal reduction of the fracture gap using anterior odontoid screws, it is essential to penetrate the apical dens tip with the screw.

The Corona Dentis: Description of an Anatomic Variant with Technical Implications for Anterior Odontoid Screw Placement.

Type 2 odontoid fractures are the most common cervical fractures among the elderly. Neurologic deficit is usually caused by myelopathy as a result of posterior dens migration. Direct anterior screw placement provides stabilization and can preserve C1-C2 movement. The presence of a bony excrescence on the anterior superior tip of the dens may lead to placement of a screw of incorrect length. Twenty C2 dry specimens were examined for the presence of a corona dentis, which is a bony excrescence in the coronal plane near the apex of the dens. When identified, measurements of the corona dentis were performed using calipers and a ruler. In addition, anteroposterior (AP) and lateral fluoroscopy was performed on all specimens found to have a corona dentis. A corona dentis was found on 20% of our C2 specimens and had an average width of 9 mm and an average height of 4.5 mm. The average width of the dens did not vary as the normal tip of the dens transitioned into the coronae. In no specimen did the corona dentis seem to be composed of trabecular bone and it was seen as a superior projection of cortical bone on fluoroscopy. On fluoroscopy, the corona dentis could be identified on a true AP projection. In angulated AP views, fluoroscopic images overestimated the length of the corona dentis. We describe a new entity termed the corona dentis because of its crownlike feature. It is a superior cortical bone protrusion and should be noted as a variant of the dens during anterior odontoid screw placement. Its propensity to increase the height of the dens markedly can lead to higher rates of neurologic deficits during type 2 odontoid fractures if not appreciated. A true AP view is critical for correct screw size placement.

Anterior retropharyngeal plate screw fixation with bilateral anterior transarticular screws for odontoid fractures ... a new comprehensive technique

Introduction: A certain group of odontoid fractures (Anderson and D’ Alonzo Type-2) are usually offered surgical treatment. Common surgical option is an anterior odontoid screw. Some of the fractures are not suitable for anterior odontoid screw (anterior oblique, displaced distal fragments and those with atlantoaxial instability) and these are usually offered posterior transarticular screws (Magerl’s) or posterior atlantoaxial screw rod/plate fixation (Goel-Harms technique). Posterior surgery involves atlantoaxial fixation with an indirect attempt to reduce and fuse the fracture . Posterior surgery has a risk of injury to the vertebral arteries, hemorrhage from the paravertebral venous plexus and the C2 root ganglion.Methods: A direct anterior submandibular retropharyangeal approach with open reduction and fixation (ORIF) using a customized variable screw placement (VSP) plate was used to realign and fix the fracture fragments in compression mode under direct vision. Twenty patients of type-II odontoid fractures (unsuitable for anterior odontoid screw) underwent an anterior retropharyngeal approach with anterior variable screw position (VSP) plate and screw fixation and eight amongst them, who had associated atlantoaxial instability underwent additional bilateral anterior transarticular screws.Results: All patients treated by this technique had 100% fracture site bone union without any implant failure. Longest follow-up has been for 3 years.Conclusion: Anterior retropharyangeal approach allows direct fracture fragment realignment under vision with an opportunity to fix in compression mode using the VSP plate, which ensures early fusion across the type-II odontoid fracture. Any associated instability can be treated by additional bilateral anterior transarticular screws. The approach is simple and safe without any risk to the vertebral arteries and biomechanically appealing.

Anterior single odontoid screw placement for type II odontoid fractures: our modified surgical technique and initial results in a cohort study of 15 patients

Objective: Anterior odontoid screw fixation for type II odontoid fracture is the ideal management option. However in the context of unavailability of an O-arm or neuro-navigation and poor images from the available C-arm may be an obstacle to ideal trajectory and placement of the odontoid screw. We herein detail our surgical technique so as to ensure a correct trajectory and subsequent good fusion in Type II odontoid fractures. This may be advantageous in clinical set ups lacking state of the art facilities. Methods and Results: In this cohort study we included 15 consecutive patients who underwent anterior odontoid screw placement. We routinely dissect the longus colli to completely visualize the entire width of C3 body. We then perform a median C2-C3 disectomy followed by creating a gutter in the superior end of C3 body. We then guide the Kirchsner (K) wire purchasing adequate anterior cortex of C2. Rest of the procedure follows the similar steps as described for odontoid screw placement. We achieved 100% correct trajectory and screw placement in our study. There were no instances of screw break out, pull out or nonunion. There was one patient mortality following myocardial infarction in our study. Conclusion: Preoperative imaging details, proper patient positioning, meticulous dissection, thorough anatomical knowledge and few added surgical nuances are the cornerstones in ideal odontoid screw placement. This may be pivotal in managing patients in developing nations having rudimentary neurosurgical set up.

Management of Type II Odontoid Fractures: Experience from Latin American Spine Centers

To analyze characteristics of type II odontoid fracture (TII-OF), including clinical and radiographic factors, that influence surgical planning in 8 Latin American centers. Retrospective chart review was performed of 88 patients with TII-OF between 2004 and 2015 from 8 Latin American centers. Parameters studied included 1) demographic data and causes of TII-OF, 2) clinical and neurologic presentation, 3) characteristics of fracture (degree of odontoid displacement, displacement of odontoid relative to C2 body, anatomy of fracture line, distance between fragments, presence of comminution, contact area between odontoid and C2 body), 4) type of treatment, and 5) clinical and radiographic outcome. Bone fusion was assessed using computed tomography. Mean patient age was 45.33 years ± 23.54; 78.4% of patients were male. Surgery was the primary treatment in 65 patients (73.8%), with an anterior approach in 64.6%. Surgery was usually preferred in patients with posterior or horizontal oblique fracture lines, local pain, and a smaller bone contact surface between the odontoid and the body of C2. A posterior approach was chosen when distance between the fractured bone fragments was >2 mm or after failed conservative or anterior odontoid screw treatment in a symptomatic patient. The treatment of choice for TII-OF in 8 Latin American trauma centers was surgery through an anterior approach using screw fixation. Posterior segmental C1-C2 fixation was indicated when distance between bone fragments was >2 mm and in symptomatic patients with nonunion.

Re-alignment of operated anterior odontoid screw displaced Odontoid type 3 without resurgery: an unusual case report with a brief review of literature

Abstract Odontoid fractures are particularly dangerous variety of cervical injury, due primarily to spinal cord trauma. In this article, we describe the re alignment of displaced operated type 3 odontoid # with anterior screw fixation with cervical traction.

Navigated odontoid screw placement using the O-arm: technical note and case series.

OBJECTIVE As odontoid process fractures become increasingly common in the aging population, a technical understanding of treatment approaches is critical. 3D image guidance can improve the safety of posterior cervical hardware placement, but few studies have explored its utility in anterior approaches. The authors present in a stepwise fashion the technique of odontoid screw placement using the Medtronic O-arm navigation system and describe their initial institutional experience with this surgical approach. METHODS The authors retrospectively reviewed all cases of anterior odontoid screw fixation for Type II fractures at an academic medical center between 2006 and 2015. Patients were identified from a prospectively collected institutional database of patients who had suffered spine trauma. A standardized protocol for navigated odontoid screw placement was generated from the collective experience at the authors' institution. Secondarily, the authors compared collected variables, including presenting symptoms, injury mechanism, surgical complications, blood loss, operative time, radiographically demonstrated nonunion rate, and clinical outcome at most recent follow-up, between navigated and nonnavigated cases. RESULTS Ten patients (three female; mean age 61) underwent odontoid screw placement. Most patients presented with neck pain without a neurological deficit after a fall. O-arm navigation was used in 8 patients. An acute neck hematoma and screw retraction, each requiring surgery, occurred in 2 patients in whom navigation was used. Partial vocal cord paralysis occurred after surgery in one patient in whom no navigation was used. There was no difference in blood loss or operative time with or without navigation. One patient from each group had radiographic nonunion. No patient reported a worsening of symptoms at follow-up (mean duration 9 months). CONCLUSIONS The authors provide a detailed step-by-step guide to the navigated placement of an odontoid screw. Their surgical experience suggests that O-arm-assisted odontoid screw fixation is a viable approach. Future studies will be needed to rigorously compare the accuracy and efficiency of navigated versus nonnavigated odontoid screw placement.

Anterior single odontoid screw placement for type II odontoid fractures: our modified surgical technique and initial results in a cohort study of 15 patients.

Objective: Anterior odontoid screw fixation for type II odontoid fracture is the ideal management option. However in the context of unavailability of an O-arm or neuro-navigation and poor images from the available C-arm may be an obstacle to ideal trajectory and placement of the odontoid screw. We herein detail our surgical technique so as to ensure a correct trajectory and subsequent good fusion in Type II odontoid fractures. This may be advantageous in clinical set ups lacking state of the art facilities. Methods and Results: In this cohort study we included 15 consecutive patients who underwent anterior odontoid screw placement. We routinely dissect the longus colli to completely visualize the entire width of C3 body. We then perform a median C2-C3 disectomy followed by creating a gutter in the superior end of C3 body. We then guide the Kirchsner (K) wire purchasing adequate anterior cortex of C2. Rest of the procedure follows the similar steps as described for odontoid screw placement. We achieved 100% correct trajectory and screw placement in our study. There were no instances of screw break out, pull out or nonunion. There was one patient mortality following myocardial infarction in our study. Conclusion: Preoperative imaging details, proper patient positioning, meticulous dissection, thorough anatomical knowledge and few added surgical nuances are the cornerstones in ideal odontoid screw placement. This may be pivotal in managing patients in developing nations having rudimentary neurosurgical set up.

Advantages of Direct Insertion of a Straight Probe Without a Guide Tube During Anterior Odontoid Screw Fixation of Odontoid Fractures.

A retrospective cohort study. The aim of this study was to compare the anterior odontoid screw fixation (AOSF) with a guide tube or with a straight probe. AOSF associates with several complications, including malpositioning, fixation loss, and screw breakage. Screw pull-out from the C2 body is the most common complication. All consecutive patients with type II or rostral shallow type III odontoid fractures who underwent AOSFs during the study period were enrolled retrospectively. The guide-tube AOSF method followed the standard published method except C3 body and C2-3 disc annulus rimming was omitted to prevent disc injury; instead, the guide tube was anchored at the anterior inferior C2 vertebra corner. After 2 screw pull-outs, the guide-tube cohort was analyzed to identify the cause of instrument failure. Thereafter, the straight-probe method was developed. A guide tube was not used. A small pilot hole was made on the most anterior side of the inferior endplate, followed by insertion of a 2.5 mm straight probe through the C2 body. Non-union and instrument failure rates and screw-direction angles of the guide-tube and straight-probe groups were recorded. The guide-tube group (n = 13) had 2 screw pull-outs and 1 non-union. The straight-probe group (n = 8) had no complications and significantly larger screw-direction angles than the guide-tube group (60.5 ± 4.63 vs. 54.8 ± 3.82 degrees; P = 0.047). Straight-probe AOSF yielded larger direction angles without injuring bone and disc. Complications were absent. The procedure was easier than guide-tube AOSF and assured sufficient engagement, even in horizontal fracture orientation cases. 3.

Treatment Options for Odontoid Fractures. A Comparasion between Anterior and Posterior Approaches

Introduction Odontoid fractures account for 9% to 15% of adult, cervical spine fractures, and are the most common fractures in the geriatric cervical spine. The mechanism of injury generally results from hyperflexion or hyperextension of the cervical spine during low-energy impacts in the elderly or high-energy impacts in the young and middle aged. No consensus exists on the optimal treatment (surgical or conservative) and the most relevant outcome parameter (osseous union, fracture stability or clinical outcome). Neurologic injuries associated with these fractures are rare. Material and Methods This study was a retrospective chart review of 13 patients who were treated for odontoid process fractures between November 2010 and May 2015. Inclusion criteria: Patients with odontoid fractures submitted to surgical treatment. Data were obtained from medical charts and spinal column imaging reports. Medical charts, imaging studies and the patient's outcomes were submitted to descriptive analysis in the pre-operative and post-operative period. The data submitted to descriptive analysis were: Fracture gaps; the direction and degree of odontoid process displacement; the odontoid fracture line anatomy; the degrees of the atlantoaxial instability; and the contact between the fractured odontoid and the axis vertebrae. We used conventional radiographs, three-dimensional computed tomographic (3D-CT) scans, and magnetic resonance images. We used the Grauer Algorithm for defining the surgical treatment modality. We identified the solid bone union through the presence of bony bridges and the definite continuity of cortical bone. Results A total of 13 patients who underwent surgical treatment for odontoid fracture were identified. The patients were 76.9% men, the mean age = 32.92 years. Traffic accidents (69,2%) were the most common cause of trauma. The main symptom was pain (84.6%) in the posterior cervical region. The elapsed median time from accident to surgery was 30 days. Mean follow-up was 20 months. Odontoid screw technics (38,4%) and Harms posterior technic (38,4%) were the most common surgical treatment adopted as primary surgical treatment. The most common Grauer's line fracture type was type B on 8 cases. 2 patients referred chronic cervical pain after surgery, 1(20%) were submitted to anterior technic and 1 (12,5%) posterior technic. We had 2 cases with complications, all submitted to posterior technic, 1 with CSF leak and 1 with vertebral artery lesion. No mortality was observed. Conclusion There was no difference between anterior or posterior approach when analyzing the cervical chronic pain and mortality. However, there were more complications in cases covered by the posterior approach. A well-designed prospective study with a larger number of cases is needed to better elucidate optimal treatment algorithms from both an outcomes and cost-effectiveness perspective.

Computational Anatomy of C2 Based on Quantitative Computed Tomography and its Implications for Screw Positioning

Introduction Surgical fixation of the axis (C2) includes screw positioning through bony corridors close to vital structures. However, human bones exhibit large variations in size and shape across individuals and populations. A 3D statistical model of C2 using Quantitative Computed Tomography (QCT) was created to analyze the anatomical variations and to understand their implications for screw positioning. Material and Methods 106 standard clinical QCTs from 46 adult female and 60 male European patients, aged 52.0 years ± 19.9 years, with intact C2s have been included in this study. The mean image resolution was 0.5mm × 0.5mm in the axial plane and 0.6mm in craniocaudally direction. After anonymization 3D statistical modeling of C2 was performed. This included the computation of averaged 3D surface and volumetric bone mineral density (vBMD) models and principal component analysis (PCA). Transpedicular and odontoid screw templates were virtually implanted and their corridors were analyzed. Results PCA revealed a highly variable anatomy of C2 in which size was the predominant variation in the 1st principal component (PC), whereas shape changes were primarily described by the remaining PCs. The largest shape variation was observed at the spinous and transverse processes and the transverse foramina. Comparison of the averaged 3D surface models of C2 for men and women separately revealed mainly a difference in size: The model for males was ~7% larger in the axial plane (anterior-posterior and left-right directions) and ~9% in craniocaudal direction. 3.5mm odontoid screw templates could be virtually implanted in all C2. The average corridor length was 39.2mm ± 2.8mm and the median screw length 38mm. The average corridor length difference between the genders was ~8%. The corridor exhibited the lowest average vBMD value (199.0 mgCaHA/ml) underneath the basis of the odontoid process and a maximum value (911.2 mgCaHA/ml) at its upper part near the cortical shell. Virtual implantation of a 3.5mm C2 pedicle screw with 1mm safety zone was not possible in 31.1% due to interference with the vertebral artery. In 26.4% a 3.5mm screw and in 42.5% a 4.5mm screw could be positioned. The median screw length was 32mm. The average pedicle corridor length was 28.7mm ± 1.9mm with an average convergence of 21.0° ± 3.6° to the sagittal plane and an average ascent of 18.7° ± 3.5° in cranial direction. The lowest average vBMD value for the corridor was located in the trabecular bone of the vertebral body (314.8 mgCaHA/ml) whereas the maximum value (689.2 mgCaHA/ml) was measured near the anterior cortical shell of the vertebral body. The average entry point was ~5mm lateral from the medial border of the inferior articular process and ~10mm cranial from its caudal border. Conclusion We established a 3D statistical model of C2 using QCTs. It revealed largely variable surfaces, bone quality and corridor dimensions and allowed the efficient 3D assessment of parameters relevant for screw positioning. There are anatomical conditions that allowed/not allowed for screw positioning. Surgical decision making must rely on both, a thorough anatomical understanding and the given individual situation. Acknowledgments This work was supported by AOSpine TK of the TK System of the AO Foundation, Davos, Switzerland. D. Gehweiler received a research fellowship grant from the AO Research Institute Davos, Davos, Switzerland.

A biomechanical evaluation of odontoid screw plate fixation system

To evaluate the biomechanical stability of anterior odontoid screw plate (AOSP). Eight fresh-frozen cadaveric cervical spine specimens were subjected to stepwise destabilization of the C1-C3 complex, simulating a type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C2-3 disc injury. Intact specimens, fractured specimens, and fractured specimens with posterior, anterior fixation techniques were divided into six groups: control group (intact), injury group of type Ⅱ odontoid fracture and type Ⅰ Hangman fracture combined with C2-3 disk injury, after anterior cervical plate+ odontoid screw+ cage (ACP+ OS+ cage) group, after anterior odontoid screw plate (AOSP) fixation system group, after affixing rods from pedicle screws in C2 to lateral mass screws in C3+ odontoid screw (C2PS+ C3LMS+ OS) group, after affixing rods from pedicle screws in C1 to pedicle screws in C2 and lateral mass screws in C3 (C1PS+ C2PS+ C3LMS) group. The range of motion (ROM) and neutral zone of C1-C2 and C2-C3 segment was tested. There was statistically significant difference between the C1PS+ C2PS+ C3LMS fixation group and the AOSP fixation group of ROMC1-C2(P<0.05). During all loading modes, AOSP+ Bone graft fixation significantly outperformed the ACP+ OS+ cage fixation in limiting ROMC2-C3. During flexion and extension, AOSP fixation significantly outperformed the C1PS+ C2PS+ C3LMS fixation and C2PS+ C3LMS+ OS fixation in limiting ROMC2-C3. The AOSP fixation system has excellent biomechanical performance when dealing with type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C2-3 disc injury, and appear to be a safe and effective technique for dealing with the combined injury.

Surgical Intervention for Instability of the Craniovertebral Junction.

Surgical approaches for stabilizing the craniovertebral junction (CVJ) are classified as either anterior or posterior approaches. Among the anterior approaches, the established method is anterior odontoid screw fixation. Posterior approaches are classified as either atlanto-axial fixation or occipito-cervical (O-C) fixation. Spinal instrumentation using anchor screws and rods has become a popular method for posterior cervical fixation. Because this method achieves greater stability and higher success rates for fusion without the risk of sublaminar wiring, it has become a substitute for previous methods that used bone grafting and wiring. Several types of anchor screws are available, including C1/2 transarticular, C1 lateral mass, C2 pedicle, and translaminar screws. Appropriate anchor screws should be selected according to characteristics such as technical feasibility, safety, and strength. With these stronger anchor screws, shorter fixation has become possible. The present review discusses the current status of surgical interventions for stabilizing the CVJ.

Progressive quadriparesis caused by anterior odontoid screw upward migration in rheumatoid arthritis

A 70-year-old male known for seropositive rheumatoid arthritis underwent placement of an anterior odontoid screw in 2005 at an outside hospital for a posttraumatic type 2 odontoid fracture (Fig. 1). At the time of the accident, he did not have documented rheumatoid changes in the cervical spine. A postoperative lateral radiograph showed the screw going beyond the distal cortex of the dens (Fig. 2). The patient initially did well and was subsequently lost to follow-up. Fig. 2Sagittal computed tomography (CT) scan reconstruction performed after anterior odontoid screw fixation with satisfactory reduction of odontoid fragment. Despite a screw going 3 mm beyond odontoid tip, it remains extracranial, below the McRae line (dotted line). View Large Image Figure Viewer Download Hi-res image

Surgical management of combined fracture of atlas associated with fracture of axis vertebrae (CAAF): Case Series

Abstract Combined fracture involving atlas together associated with axis (CAAF) accounts for approximately 3 % of traumatic cervical spine injury, CAAF are rarely reported, so modalities of management and outcome are not well understood, due to paucity of literature and only few reports reported in the form of isolated case report. CAFF management possess challenge as it is associated with high incidence non-union with previously conservative method. However, missed diagnosis and subsequent delay may be associated with catastrophic worsening in neurological deficit. So early diagnosis and management remains the key for successful neurological outcome. Such fractures are rare. Authors report five such cases of CAFF, all required surgical management with good outcome with no mortality. Current study, all cases were males (n=5), commonest mode of injury was fall (n=3), time interval since injury was within 24 hours in (n=4), however rest one presented after a gap of eight months. Commonest clinical feature was neck pain (n=3), neurological deficit (n=2), neck tenderness and swelling tenderness (n=3) Neuroimaging including X-ray, CT scan and MRI were carried out for all cases revealed fracture of arches of atlas (n=5), one case had multiple site fracture of both arches, odontoid fracture (n=2), lateral mass of atlas fracture in 1 cases. Astonishingly two cases had disruption of transverse ligament. Surgical procedures performed considering economic consideration included occipito-cervcial fusion (n=3), transarticular C1-C2 fusion and anterior odontoid screw fixation in one cases each. Management options in CAFF and review of literature discussed in present study.

The Anterior "Triple-/Quadruple" Technique for C1/C2 Trauma in the Elderly: First Experience with 16 Patients

In geriatric patients the management of odontoid type II fractures is complicated by osteoporosis and atlantoaxial arthritis (spondylarthritis C1/C2) with an increased lever arm. Furthermore, a few of the odontoid fractures are accompanied by an atlas fracture resulting in the "atlantoaxial unhappy triad". Posterior C1/C2 spondylodesis with bilateral Magerl screws and C1 hooks is a strong biomechanical construct, however, the posterior approach is associated with several drawbacks such as increased risk of infection and increased blood loss. In contrast, the anterior bilateral C1/C2 transarticular screw fixation with additional odontoid screw fixation is also a known technique. Advantages of the anterior approach are shorter surgery time, lower intraoperative blood loss and lower risk of infection. In this retrospective study, all geriatric patients with an atlantoaxial arthritis and odontoid or combined atlantoaxial fracture treated at our institution between 01/2012 and 12/2014 with an anterior screw fixation were included. Following closed reduction, the surgical management was performed over a standard right anterior approach. At the end of surgery, operation time and blood loss were documented. During the hospital stay radiological follow-up of the upper cervical spine were performed to analyse the screw position. We also report the length of stay on intensive care unit, the hospital course and demographic data of the patients. Follow-up was planned after 6 weeks, 6, 12 and 18 months. During follow-up COMI evaluation and X-rays of the cervical spine were made. This study included 16 patients who underwent surgery for C1-C2 lesions. There were 9 females and 7 males. Median age at the time of operation was 76 years. At the time of surgery, fractures were classified as follows: 8 patients showed an "atlantoaxial unhappy triad", 8 patients had a type II odontoid fracture complicated by osteoporosis and atlantoaxial arthritis (spondylarthritis C1/C2). Average time for operative treatment was 100 ± 36.35 minutes with a median intraoperative fluoroscopy time of 161 seconds. The intraoperative blood loss was minimal (45 ± 22.80 ml). Length of stay was documented with 10 (± 4.60) days whereby the patients spent on average 0.8 days in the intensive care unit postoperatively. No serious morbidities, such as esophageal perforation, carotid artery laceration, neurological deterioration, and airway obstruction were reported. All cases of transient dysphagia resolved gradually and spontaneously without therapy. In 4 cases (25 %) we detected a penetration of the atlantooccipital joint without functional impairment. In one case we have seen an implant failure. The technique of anterior screw fixation of odontoid and bilateral transarticular C1-C2 anterior screw fixation provides a fast surgery without higher morbidity. Based on our findings, this technique and its feasibility is an alternative to known posterior C1/C2 spondylodesis in the elderly.

Cement-augmented anterior odontoid screw fixation for osteoporotic type II odontoid fractures in elderly patients: prospective evaluation of 11 patients.

Osteoporosis is considered to be a relative contraindication for anterior screw fixation of odontoid fractures because of reduced screw purchase. In the presence of osteoporosis, the most frequent mode of implant failure is via cut-out through the anterior wall of C2. Under in vitro conditions, cement-augmented odontoid screws show significant biomechanical advantages as compared to non-augmented screws. Against this background, we present our prospectively collected data on cement-augmented anterior screw fixation of osteoporotic odontoid fractures in elderly patients. 11 patients (8 female, 3 male, median age 83 years, range 73-89 years) with an isolated, osteoporotic type II odontoid fracture were treated. After closed reduction and standard anterior approach to the C2/3 level, a self-tapping, short-threaded 3.5-mm lag screw was placed. High-viscosity polymethylmethacrylate cement was injected via a cannulated Jamshidi needle into the base of the C2 vertebral body around the screw shaft and the screw was further tightened. Thin slice CT reconstructions for follow-up evaluation were done consistently postop and 12 months after surgery. Anatomic fracture reposition was achieved in all patients. Cement application was uneventful and well controllable. Cement leakage towards the fracture gap was not detectable. There were no major perioperative complications and no early revision surgeries. After 1 year, thin slice CT with three-dimensional reconstruction demonstrated solid osseous healing of the odontoid fracture in 8 out of 10 patients. Additional cement augmentation for anterior odontoid fracture repair is technically easy and safe. In elderly people with osteoporotic odontoid fractures, the procedure seems to be a useful supplementary option.

Trends in Epidemiology and Management of Traumatic Type II Odontoid Fracture: Experience in Latin America

Introduction Odontoid fractures (OF) are frequent in the trauma population, and there is no universally accepted single method of management. The objective of this study was to evaluate the epidemiology and management of type II OF in Latin America treated either with rigid cervical orthosis or surgery. Patients and Methods A total of 83 patients treated conservatively or by surgery were enrolled in this retrospective study. Medical charts, imaging studies, and outcomes of patients were analyzed in the pretreatment period and at the last medical evaluation. The fractures were assessed using conventional radiographs, three-dimensional computed tomographic (3D-CT) scans, and magnetic resonance images. Fracture gaps, the direction and the degree of displacement of the odontoid process, the fracture line anatomy, the degrees of atlantoaxial instability, the comminuted fracture, and the surface contact area were analyzed. The decision for operative or nonoperative treatment was based on anesthesia risk, and patient's choice of the nonoperative treatment. The nonoperative management generally consisted of a rigid cervical orthosis for 3 months. The type of surgery to be performed was chosen by the surgeon. The solid bony union was defined as the presence of bony bridges and the definite continuity of cortical bone. Fibrous union was considered present when no degree of motion was evident in dynamic radiographs despite persistent cortical bone discontinuity within a fracture gap on 3D CT scans. Nonunion was defined as a definite fracture gap with abnormal motion of the fractured dens on dynamic radiographs and on a 3D CT scan. Results A total of 83 patients were included in this study. The patients were 78.3% men, the mean age = 44.98 ( ± 23.20 years) years. Traffic accidents (66.3%) were the most common cause of trauma. The main symptom was pain (85.5%) in the posterior cervical region. The median time elapsed from accident to surgery was 7 days (P25: 2/P75: 27.5). Median follow-up was 23.66 ( ± 25.43 months) months. Conservative treatment with cervical orthosis, for example, Miami J collar or halo-vest was used in 20.5% of the cases. Odontoid screw technics (57.6%) were the most common surgical treatment adopted as primary surgical treatment. Symptomatic nonunion was observed in two cases with conservative treatment and three cases after odontoid screw fixation. All the patients were referred to posterior C1–C2 fixation. The posterior fixation tended to be used after conservative failed therapy, after nonunion anterior screw surgery, and in fractures with greater displacement. The most common radiological feature was no displacement of the odontoid process in relation to the body of C2, horizontal fracture line, gap fracture &lt; 2 mm, no subluxation across each C1–C2 facet joint and no comminuted fracture. Conclusion The patients treated nonoperatively with a rigid collar may have an overall favorable outcome compared with surgical treatment. A well-designed prospective study is needed to better elucidate optimal treatment algorithms from both an outcomes and cost-effectiveness perspective.

Surgical treatment of Type II odontoid fractures: anterior odontoid screw fixation or posterior cervical instrumented fusion?

Odontoid fractures comprise as many as 20% of all cervical spine fractures. Fractures at the dens base, classified by the Anderson and D'Alonzo system as Type II injuries, are the most common pattern of all odontoid fractures and are also the most common cervical injuries in patients older than 70 years of age. Surgical treatment is recommended for patients older than 50 years with Type II odontoid fractures, as well as in patients at a high risk for nonunion. Anterior odontoid screw fixation (AOSF) and posterior cervical instrumented fusion (PCIF) are both well-accepted techniques for surgical treatment but with unique indications and contraindications as well as varied reported outcomes. In this paper, the authors review the literature about specific patients and fracture characteristics that may guide treatment toward one technique over the other. AOSF can preserve atlantoaxial motion, but requires a reduced odontoid, an intact transverse ligament, and a favorable fracture line to achieve adequate fracture compression. Additionally, older patients may have a higher rate of pseudarthrosis using this technique, as well as postoperative dysphagia. PCIF has a higher rate of fusion and is indicated in patients with severe atlantoaxial misalignment and with poor bone quality. PCIF allows direct open reduction of displaced fragments and can reduce any atlantoaxial subluxation. It is also used as a salvage procedure after failed AOSF. However, this technique results in loss of atlantoaxial motion, requires prone positioning, and demands a longer operative duration than AOSF, factors that can be a challenge in patients with severe medical conditions. Although both anterior and posterior approaches are acceptable, many clinical and radiological factors should be taken into account when choosing the best surgical approach. Surgeons must be prepared to perform both procedures to adequately treat these injuries.