C1-C2 Joint Research Articles

Six Different Vertebral Artery Configurations, in Three Subjects Commanding Different Approaches for C1-C2 Distraction and Fixation in Cases of CVJ Anomaly: A Case Series

Introduction There are various choices to fix up Atlanto-Axial dislocation (AAD) and Basilar invagination (BI), it may be Posterior only, Anterior only or Combined. Many surgeons refrain from “posterior only” approach of C1-C2 distraction (as described by Atul Goel and Lahiri) because of the fear of Vertebral artery (VA) injury and it's poorly understood course between C1, C2, and Occipital condyles. We describe details of preoperative work and subsequently adopted, customized surgical plans, as per VA configuration to distract & fix the C1-C2 joint to achieve reduction in AAD and BI without harming the Vertebral artery. This case series covers most of the variations of VA around C1-C2 for learning purpose. After seeing this work up, many surgeons may allay their anxieties and take up this single stage corrective measure to achieve correction of deformities in cases of AAD & BI. In the due course author will also explain different variations of Vertebral artery not only in different individuals, but also in same subject on either sides. We describe the adaptive surgical methods taken based on these data to avoid injury to VA, and still achieve a firm distraction and fixation at C1-C2 with this single stage. The technique can thus be extrapolated in various other cases of AAD and BI with hardly any exception. Material and Methods Three serial patients with an established diagnosis of Atlanto-axial dislocation and Basilar invagination are described. All three were evaluated with 3-D MPR CT with vertebral artery angiography (CTA-VA), and MRI at Cervico-medullary junction (MRI-CMJ). The VA in one subject was going through pedicle on one side and in another subject, it was going around the C1-C2 facet joint, while in another case it was entirely intra-spinal. The radiological evaluation was done in both pre and post operative period to describe anomalies of CVJ, different courses of VA and vectors thus used for potential instrumentation. Postoperative scans were used to see adequacy of fixation. Results There was a clear evidence of highly variable course in VA of all three subjects. There were different courses in right and left VAs as well, commanding different choices of instrumentation on both sides in a single individual. All patients achieved reduction of AAD & BI and there was no injury to the vascular structure in question. They all improved in clinical signs and symptoms in the due course. Conclusion Authors conclude that it's mandatory to subject all patients to CT angiography in an order to view the Vertebral artery course wrt C1-C2 facets, which is not only variable in different individuals but also, on both sides in same individual, hence even in a single patient we may need different instrumentation to achieve the same goal. The authors also conclude that instrumentation at C1-C2 without CTA-VA is not only dangerous but can be fatal as well, hence instrumentation done without the above mentioned study should be considered a mandatory practice in the safest interest of patients and to achieve optimum and customized instrumentation.

New entry point for C2 screw, in posterior C1-C2 fixation (Goel-Harm’s technique) significantly reducing the possibility of vertebral artery injury

Objective: To reduce the chance of vertebral artery injury in posterior C1 lateral mass and C2 pedicle/pars screw–rod fixation (Goel–Harms technique ).Method: 49 patients, 30 males and 19 females, 12years - 82 years, underwent posterior C1–C2 fixation from February 2007 till June2013. A new entry point for the posterior C2 screw, 3mm below the midpoint of the C1–C2 joint which is directed medially and downwards into the C2 body , probably avoids the vertebral artery. As the screw now bypasses the pedicle/ pars , the chance of injuring the vertebral artery is probably reduced.Results: No case of intra-operative vertebral artery injury.Conclusion: The new technique of C2 screw fixation allows rigid immobilization of the C1–C2 joint without significant risk of vertebral artery injury.

Occult Cranial Cervical Dislocation: A Case Report and Brief Literature Review

Study Design. Retrospective case report and review. Objective. Cranial cervical dislocation (CCD) is commonly a devastating injury. Delay in diagnosis has been found to lead to worse outcomes. Our purpose is to describe a rare case of occult cranial cervical dislocation (CCD) and use it to highlight key clinical and radiographic findings to ensure expedited diagnosis and proper management avoiding delays and subsequent neurologic deterioration. Method. Case report with literature review. Results. We describe a unique case of occult cranial cervical dislocation where initial imaging of the cervical spine failed to illustrate displacement of the occipital-cervical (O-C1) articulation or C1-C2 articulation. Careful evaluation of subtle radiographic clues suggested a more severe injury than initial review. Additional imaging was obtained due to these subtle clues confirming true cranial cervical dislocation allowing subsequent treatment with no neurologic sequelae. Conclusion. A high index of suspicion of CCD may prevent injury in select patients who present without gross cord compromise. Careful consideration of associated fractures, soft tissue injuries, and mechanism of injury are essential clues to the correct diagnosis and management of injuries to the craniocervical junction (CCJ).

Nonoperative Management of Craniocervical Ligamentous Distraction Injury: Literature Review

Study Design Literature review and case report. Objective Review the existing literature and report the successful nonoperative management of a two-level craniocervical ligamentous distraction injury. Methods A PubMed and Medline review revealed only three limited reports involving the nonoperative management of patients with craniocervical distraction injury. This article reviews the existing literature and reports the case of a 27-year-old man who was involved in a motorcycle accident and sustained multiple systemic injuries and ligamentous distraction injuries to both occipitocervical joints and both C1–C2 joints. The patient's traumatic brain injury and bilateral pulmonary contusions precluded safe operative management of the two-level craniocervical distraction injury. Therefore, the patient was placed in a halo immobilization device. Results The literature remains unclear as to the specific indications for nonoperative management of ligamentous craniocervical injuries. Nonoperative management was associated with poor outcomes in the majority of reported patients. We report a patient who was managed for 6 months in a halo device. Posttreatment computed tomography and flexion–extension radiographs demonstrated stable occipitocervical and C1–C2 joints bilaterally. The patient reported minimal neck pain and had excellent functional outcome with a Neck Disability Index score of 2 points at 41 months postoperatively. He returned to preinjury level of employment without restriction. Conclusions Further study is needed to determine which craniocervical injuries may be managed successfully with nonoperative measures.

C2 Subfacetal Body Screw in Posterior Atlantoaxial Fixation (Goel–Harm Technique) to Avoid the Vertebral Artery

Introduction Axis (C2) pedicle/pars screw fixation has a definite risk of injury to the vertebral artery. An alternative trajectory 3 mm below the midpoint of the C2 facet surface, directed, downwards and medially into the C2 body, bypasses the vertebral artery altogether, and still offers adequate bone stock for rigid fixation of the C2 vertebra. Material and Methods Overall, 65 patients, 40 males and 25 females, aged 12 to 82 years, underwent posterior C1–C2 fixation from February 2007 to June 2014. Reducible atlantoaxial instability due to trauma (35), rheumatoid arthritis (20), and infection (tuberculosis) (10), magnetic resonance imaging (MRI), dynamic lateral X-rays of craniovertebral junction (CVJ), 3D CT scan of the craniovertebral region along with dynamic study and CT angiography. The entry point for the C2 screw was 2 to 3 mm below the midpoint of superior facet of the C2 which is also the midpoint C1–C2 joint and directed 10–to 15 degrees medially and downwards into the body of the axis. The same 3-mm drill bit was used incrementally till a depth of 5 mm and, 3.5 mm and 18 to 24mm length self-tapping screw with polyaxial head was used in most cases. Results No case of intraoperative vertebral artery injury. No patient required per operative blood transfusion. Follow-up visits were scheduled at 2, 6 to 8 weeks, and 3 months. Dynamic X-ray imaging was done in all patients at 6 to 8 weeks before discontinuing the collar and after 3 months since the operation. All patients followed up for 3 months. Telephonic follow-up of 30 patients was available for 24 months, 12 patients for 6 months, and remaining 7 patients have not reported and are not contactable after the 3 month visit. One postoperative mortality due to myocardial infarction on 7th day. Seven patients complained of occipital numbness and paresthesia which was not disturbing and responded to reassurance and supportive medication (pregabalin). Two patients had superficial wound infection which responded to appropriate antibiotics. There was no case of implant failure or loss of rigidity of fixation up to 3 months. Conclusion The new entry point offers rigid fixation and avoids the vertebral artery altogether nullifying the chance of arterial injury. Divergent screws (bridge vs. tension band construct) have a greater pull out strength. The new technique of C2 screw fixation allows rigid immobilization of the C1–C2 joint without any risk of vertebral artery injury.

Anterior Extrapharyngeal Fixation of the Atlanto–Axial Joints

Introduction The atlanto–axial joints can be easily exposed from a unilateral submandibular extrapharyngeal approach. Decortication and intrajoint bone grafting can be easily accomplished. Rigid anterior fixation of the joint is possible without any risk to the vertebral arteries. Materials and Methods Between April 2008 and September 2014, 95 patients, 50 male and 45 female patients, in the age group of 12 to 82 years, were offered this procedure. 55 patients had anterior transarticular screws, 40 patients had anterior screw plate fixation (AAD 63 patients, tuberculosis 20, fixed AAD with Basilar invagination 12). All patients underwent preoperative dynamic X-rays of craniovertebral junction, computerized tomography (CT scan) of C1–C2 static and dynamic study with bone window settings and 3D reconstruction, magnetic resonance imaging (MRI), and MR angiography to study the course of vertebral artery. Stevenson technique (22 patients) for exposure to reach the prevertebral space at C1–C2. Technique 1: plate and screws (C1 lateral mass and C2 body); Technique 2: anterior transarticular screws across C1–C2 joint. Results Average procedure time was 3 hours, no case required blood transfusion, reoperation occurred in seven cases; three screw malposition both ipsilateral (right sided), reoperated within 48 hours and screw repositioned correctly. One overdistraction of C1–C2 joint due to screw not piercing the C1 lateral mass and pushing the lateral mass of C1 away from C2 (because of inadequate drilling of C1 lateral mass). Reoperated on the 3rd day and lateral mass of C1 drilled correctly and the screw passed successfully. Two inadequate excisions of odontoid process had to be removed transorally after 3 weeks because of excessive backward angulation of odontoid process. One case of screw loosening that was due to incorrect plate contouring, reoperation after 3 weeks when patient had come for first postoperative follow-up. Follow-up in 75% for 24 months. Rigid fixation in 100%, mortality 0%. Conclusion Anterior extrapharyngeal approach allows for reduction of the atlanto–axial dislocation, opportunity for bone grafting of the joint, and with anterior C1 lateral mass and C2 body screw plate fixation or anterior transarticular screws, provides rigid fixation without any risk to the vertebral artery, venous plexus, or spinal cord.

The Fate of Type II Odontoid Fractures after Posterior Atlantoaxial Fusion: Where Does Healing Occur?

Anderson and D'Alonzo type II odontoid fractures often require surgical intervention. Our goal was to understand the pattern of healing in patients who had a posterior atlantoaxial fusion for a type II odontoid fracture. We conducted a retrospective study of patients who underwent posterior atlantoaxial instrumentation and fusion for a type II odontoid fracture at our institution between 1987 and 2011. Patients who had fusion evaluation by computed tomography (CT) scan ≥3 months after surgery were included. Surgical technique included placement of a posterior bone graft with transarticular screws, C1 lateral mass and C2 pars/pedicle screw construct, or a combination of screw fixation techniques. Postoperative CT scans were reviewed to determine the site where fusion occurred. Sixty-four patients underwent posterior atlantoaxial instrumentation and fusion for type II odontoid fractures, 12 of whom had fusion evaluation by CT scan. A total of 11 of 12 patients had fusion across the fracture site, 2 across the C1-C2 joint, and 11 at the posterior graft site. All 12 patients had at least one site of fusion. There is a high rate of fusion across the fracture site of a type II odontoid fracture after posterior atlantoaxial fixation. In young patients with acute type II fractures who are not candidates for anterior screw fixation, posterior atlantoaxial instrumentation without fusion may be sufficient for fracture healing, thus allowing for the possibility of implant removal and preservation of C1-C2 motion.

Anterior transoral atlantoaxial release and posterior instrumented fusion for irreducible congenital basilar invagination.

Recently, it has been demonstrated that anterior release of tight structures via a transoral approach can assist posterior distraction-reduction technique in restoring the cranio-cervical anatomy in irreducible atlantoaxial dislocations. Our aim was to evaluate the radiological and clinical outcome of anterior release and posterior instrumentation for irreducible congenital basilar invagination. A consecutive series of 15 patients (2007-2009) with irreducible congenital basilar invagination were treated with anterior release using transoral approach. A retrospective chart review was performed. All patients presented with myelopathy. Dislocation was treated as irreducible if acceptable reduction was not achieved with traction under general anesthesia and neuromuscular paralysis. The anterior release comprised of transverse sectioning the longus colli and capitis, C1-C2 joint capsular release and intra-articular adhesiolysis with or without anterior C1 arch excision. Cantilever mechanism using posterior instrumentation was used to correct any residual malalignment. Mean age was 21.4 (10-50) years. Average duration of follow-up was 28 (24-40)months. The average preoperative JOA score was 11.4 (8-16), which improved to 15.4 (10-18) after surgery. Anatomical reduction was achieved in thirteen patients. Fusion was documented in all patients. Complications included persistent nasal phonation in one, and superficial wound dehiscence in one. We believe that a significant number of irreducible dislocations can be anatomically reduced with this procedure thus avoiding odontoid excision. Encouraging results from this short series have given us a new perspective in dealing with these challenging problems.

In vitro biomechanics of the craniocervical junction—a sequential sectioning of its stabilizing structures

Background contextOccipitocervical dislocations involve translations of the craniocervical joints. The relative contributions of each ligament to overall stability and the effects of the occipitoatlantal joint capsules on the pathologic translation are unknown. Although incidences of occipitocervical dislocations are rare after blunt trauma, they are usually fatal. When patients do survive these dislocations, the proper diagnosis is difficult, which in turn may increase the fatality rate. A biomechanical model may provide a greater pathologic understanding of craniocervical subluxation. PurposeThe purpose of the study is to build an in vitro biomechanical model to determine which stabilizing ligament(s) of the craniocervical junction are most important in restraining rotation and translations during these rotations. This may guide clinical diagnosis, which could assist in treatment options. Study design/SettingThe study design includes a biomechanical cadaveric test. MethodsSeven cadaveric specimens were tested using a 6-degree-of-freedom spine simulator under the following conditions: intact, clivus/alar removal (CR), transverse ligament destruction (TLD), occipitoatlantal (OA) joint capsulotomyoccipitoatlantal (OA) joint capsulotomy (C0–C1 JC), and C1–C2 joint capsulotomy (C1–C2 JC). Flexion-extension (FE), lateral bending (LB), and axial rotation (AR) were applied (2.5 Nm) to a C0–C2 segment, whereas anterior-posterior (AP) and cranial-caudal (CC) translations were recorded. Average motions were normalized to intact (100%) for each joint. ResultsIncreases in C0–C1 angular and translational motions occurred after TLD and C0–C1 JC. At the atlantoaxial joint, there were significant (p<.05) increases from intact in FE (TLD=154%, C0–C1 JC=174%) and in AR (TLD=178%, C0–C1 JC=224%). Anterior-posterior translation during applied LB increased significantly after TLD (248% intact). Cranial-caudal translation during applied FE increased significantly after TLD (188%) and C0–C1 JC (361%). Increases in C1–C2 angular motion occurred after TLD and C1–C2 JC and in translation after CR and TLD. At the C1–C2 joint, there were significant increases from intact in FE (TLD=172%, C1–C2 JC=160%) and in LB (TLD=286%, C1–C2 JC=332%); in AR, there were no statistical differences. Anterior-posterior translation increased significantly after CR (280%). Cranial-caudal translation also increased significantly after CR (205%) and TLD (298%) during LB. ConclusionsTransverse and alar ligaments appear to be the main stabilizers of the craniocervical junction. The vertical structures attached to the clivus and OA joint capsules function as secondary stabilizers. Craniocervical dislocations seem to affect FE and lateral bending the most, whereas increased translation seems to occur primarily in the AP and CC directions. Models of craniocervical trauma should section all three restraining structures for the future studies.

Placement of C1 Pedicle Screws Using Minimal Exposure: Radiographic, Clinical, and Literature Validation.

Traditional C1-2 fixation involves placement of C1 lateral mass screws. Evolving techniques have led to the placement of C1 pedicle screws to avoid exposure of the C1-C2 joint capsule. Our minimal dissection technique utilizes anatomical landmarks with isolated exposure of C2 and the inferior posterior arch of C1. We evaluate this procedure clinically and radiographically through a technical report. Consecutive cases of cranial-vertebral junction surgery were reviewed for one fellowship trained spinal surgeon from 2008-2014. Information regarding sex, age, indication for surgery, private or public hospital, intra-operative complications, post-operative neurological deterioration, death, and failure of fusion was extracted. Measurement of pre-operative axial and sagittal CT scans were performed for C1 pedicle width and C1 posterior arch height respectively. 64 patients underwent posterior cranio-vertebral junction fixation surgery. 40 of these patients underwent occipital-cervical fusion procedures. 7/9 (77.8%) C1 instrumentation cases were from trauma with the remaining two (22.2%) from oncologic lesions. The average blood loss among isolated C1-C2 fixation was 160cc. 1/9 patients (11.1%) suffered pedicle breech requiring sub-laminar wiring at the C1 level. On radiographic measurement, the average height of the C1 posterior arch was noted at 4.3mm (range 3.8mm to 5.7mm). The average width of the C1 pedicle measured at 5.3mm (range 2.8 to 8.7mm). The patient with C1 pedicle screw failure had a pedicle width of 2.78mm on pre-operative axial CT imaging. Our study directly adds to the literature with level four evidence supporting a minimal dissection of C1 arch in the placement of C1 pedicle screws with both radiographic and clinical validation. Justification of this technique avoids C2 nerve root manipulation or sacrifice, reduces bleeding associated with the venous plexus, and leaves the third segment of the vertebral artery unexplored. Pre-operative review of imaging is critical in the placement of C1-C2 instrumentation.

Computed tomography-guided C2 pedicle screw placement for treatment of unstable hangman fractures.

Case series and description of technique. The purpose of this study was to evaluate the feasibility and accuracy of inserting pedicle screws in unstable Hangman fracture cases by using intraoperative CT (O-arm) based navigation. Hangman fracture, also known as traumatic spondylolisthesis of the C2, is defined as a fracture involving the lamina, articular facets, pedicles, or pars of the axis vertebra. Opinions vary regarding the optimal treatment of unstable Hangman fractures. Some authors have recommended the use of rigid orthosis, whereas others have recommended surgical stabilization. The peculiar anatomy of the upper cervical spine is highly variable, and the presence of surrounding neurovascular structures makes pedicle screw fixation even more technically challenging. The advent of intraoperative 3-dimensional navigation systems permits safe and accurate instrumentation of the cervical spine. Ten patients with unstable Hangman fracture, with age ranging from 17 years to 81 years, were operated under O-arm-based navigation, and screw position was confirmed with intraoperative computed tomographic scan. A total of 52 screws were inserted under O-arm guidance: 20 in C2 pedicle, 20 in C3 lateral mass, and rest in C4 lateral mass. Screw misplacement was seen in only 1 C2 pedicle screw (1 of 20, 5%). No new-onset neurological deficit developed in any of the patients. Follow-up ranged from 3 months to 21 months. Bony fusion was achieved in all. Full rotation was preserved at C1-C2 joint. All the patients (50%) with neurological deficits before surgery improved after surgery. This series demonstrates that C2 pedicle screws can be put with precision under O-arm-guided navigation, and intraoperative computed tomographic scan can confirm position of screws. Patients can be operated and mobilized early with negligible risk of screw misplacement, with preservation of motion at the C1-C2 joint. 4.

Unstable Jefferson fractures: Results of transoral osteosynthesis.

Background:Majority of C1 fractures can be effectively treated conservatively by immobilization or traction unless there is an injury to the transverse ligament. Conservative treatment usually involves a long period of immobilization in a halo-vest. Surgical intervention generally involves fusion, eliminating the motion of the upper cervical spine. We describe the treatment of unstable Jefferson fractures designed to avoid these problems of both conservative and invasive methods.Materials and Methods:A retrospective review of 12 patients with unstable Jefferson fractures treated with transoral osteosynthesis of C1 between July 2008 and December 2011 was performed. A steel plate and C1 lateral mass screw fixation were used to repair the unstable Jefferson fractures. Our study group included eight males and four females with an average age of 33 years (range 23-62 years).Results:Patients were followed up for an average of 16 months after surgery. Range of motion of the cervical spine was by and large physiologic: Average flexion 35° (range 28-40°), average extension 42° (range 30-48°). Lateral bending to the right and left averaged 30° and 28° respectively (range 12-36° and 14-32° respectively). The average postoperative rotation of the atlantoaxial joint, evaluated by functional computed tomography scan was 60° (range 35-72°). Total average lateral displacement of the lateral masses was 7.0 mm before surgery (range 5-12 mm), which improved to 3.5 mm after surgery (range 1-6.5 mm). The total average difference of the atlanto-dens interval in flexion and extension after surgery was 1.0 mm (range 1-3 mm).Conclusions:Transoral osteosynthesis of the anterior ring using C1 lateral mass screws is a viable option for treating unstable Jefferson fractures, which allows maintenance of rotation at the C1-C2 joint and restoration of congruency of the atlanto-occipital and atlantoaxial joints.

Anterior Fixation of Atlantoaxial Joints: Technique and Pitfalls

Both the atlantoaxial joints can be exposed adequately by an unilateral extrapharyngeal approach from the right side. The atlantoaxial dislocation can be reduced, joints can be decorticated and bone graft can be introduced into the joint. The odontoid process can be drilled and removed. The C1-C2 joint can be fixed either by (1) C1 lateral mass and C2 body screw plate bilaterally, or (2) bilateral anterior C2-C1 transarticular screws.

Posterior Bilateral Supernumerary Atlantoaxial Facets

Case report. To describe a symptomatic patient with bilateral posterior accessory C1-C2 joints and their differences from the true synovial joints. Accessory joints between C1-C2 are rarely described. Origin and functional importance of such joints is unknown. Moreover only gross anatomic features of such joints were discussed in the past. The emphasis here is to review the morphology of such joints and to differentiate it from normal synovial joints. A 17-year-old male presented with progressive spastic ataxia precipitated by episodic transient quadriparesis secondary to trivial trauma. Radiology revealed bilateral posterior C1-C2 accessory joints compressing the cervicomedullary junction. Both C1-C2 posterior arches were removed, excising the accessory joints. Fusion was achieved using C1-C2 lateral mass screws and is doing well at follow-up. The surfaces of these joints were smooth. Histopatholgy showed opposing osseous surfaces with articular cartilage but no synovium or articular capsule. Accessory C1-C2 joints are possibly a result of genetic aberration giving rise to abnormality in segmentation of C1 sclerotome. These joints are dysmorphic and partially formed as evidenced by the absence of synovial membrane and capsule. The function of such joints remains questionable.

Cement-augmented anterior screw fixation of Type II odontoid fractures in elderly patients with osteoporosis

Background contextClosed reduction and internal fixation by an anterior approach is an established option for operative treatment of displaced Type II odontoid fractures. In elderly patients, however, inadequate screw purchase in osteoporotic bone can result in severe procedure-related complications. PurposeTo improve the stability of odontoid fracture screw fixation in the elderly using a new technique that includes injection of polymethylmethacrylat (PMMA) cement into the C2 body. Study designRetrospective review of hospital and outpatient records as well as radiographs of elderly patients treated in a university hospital department of orthopedic surgery. Patient sampleTwenty-four elderly patients (8 males and 16 females; mean age, 81 years; range, 62–98 years) with Type II fractures of the dens. Outcome measuresComplications, cement leakage (symptomatic/asymptomatic), operation time, loss of reduction, pseudarthrosis and revision surgery, patient complaints, return to normal activities, and signs of neurologic complications were all documented. MethodsAfter closed reduction and anterior approach to the inferior border of C2, a guide wire is advanced to the tip of the odontoid under biplanar fluoroscopic control. Before the insertion of one cannulated, self-drilling, short thread screws, a 12 gauge Yamshidi cannula is inserted from anterior and 1 to 3 mL of high-viscosity PMMA cement is injected into the anteroinferior portion of the C2 body. During polymerization of the cement, the screws are further inserted using a lag-screw compression technique. The cervical spine then is immobilized with a soft collar for 8 weeks postoperatively. ResultsAnatomical reduction of the dens was achieved in all 24 patients. Mean operative time was 64 minutes (40–90 minutes). Early loss of reduction occurred in three patients, but revision surgery was indicated in only one patient 2 days after primary surgery. One patient died within the first eight postoperative weeks, one within 3 months after surgery. In five patients, asymptomatic cement leakage was observed (into the C1–C2 joint in three patients, into the fracture in two). Conventional radiologic follow-up at 2 and 6 months confirmed anatomical healing in 16 of the19 patients with complete follow-up. In two patients, the fractures healed in slight dorsal angulation; one patient developed a asymptomatic pseudarthrosis. All patients were able to resume their pretrauma level of activity. ConclusionsCement augmentation of the screw in Type II odontoid fractures in elderly patients is technically feasible in a clinical setting with a low complication rate. This technique may improve screw purchase, especially in the osteoporotic C2 body.

Reduction techniques in the management of atlantoaxial subluxation.

Background:The traditional approach to atlantoaxial subluxation which is irreducible after traction is transoral decompression and reduction or odontoid excision and posterior fixation. Transoral approach is associated with comorbidities. However using a posterior approach a combination of atlantoaxial joint space release and a variety of manipulation procedures, optimal or near optimal reduction can be achieved. We analysed our results in this study based on above procedure.Materials and Methods:66 cases treated over a 5 year period were evaluated retrospectively. Three cases treated by occipito cervical fusion were not included in the study. The remaining 63 cases were classified into three types. All except two cases were subjected to primary posterior C1-C2 joint space dissection and release followed by on table manipulation which was tailored to treat the type of atlantoaxial subluxation. Optimal or near optimal reduction was possible in all cases. An anterior transoral decompression was needed only in two cases where a bony growth (callus) between the C1 anterior arch and the odontoid precluded reduction by posterior manipulation. All cases then underwent posterior fusion and fixation procedures. Patients were neurologically and radiologically evaluated at regular followups to assess fusion and stability for a minimum period of 6 months.Results:Of the 63 cases who underwent posterior manipulation, 49 cases achieved optimum reduction and the remaining 14 cases showed near optimal reduction. Two cases expired in the postoperative period. None of the remaining cases showed neurological worsening after the procedure. Evaluation at 6 months after surgery revealed good stability and fusion in all except three cases.Conclusion:Atlantoaxial joint release and manipulation can be used to achieve reduction in most cases of atlantoaxial subluxation, obivating the need of transoral odontoid excision.

Comparative Analysis of Isocentric 3-dimensional C-arm Fluoroscopy and Biplanar Fluoroscopy for Anterior Screw Fixation in Odontoid Fractures

Retrospective clinical study. To compare long-term radiographic and clinical outcomes of patients undergoing anterior odontoid screw placement using traditional biplanar fluoroscopy or isocentric 3-dimensional C-arm (iso-C) fluoroscopy-assisted techniques. Anterior screw fixation of odontoid fractures preserves motion at the C1-C2 joint, but accurate screw positioning is essential for successful outcomes. Biplanar fluoroscopy image guidance is most often used; however, iso-C imaging improves the ease and accuracy of screw placement with less radiation exposure. Fifty-one patients underwent anterior odontoid screw fixation for type II (48 patients) and rostral type III fractures (3 patients). Procedures were guided by biplanar fluoroscopy in 25 (49%) patients, and with iso-C assistance in 26 (51%). Length of surgery, complications, and clinical outcomes based on the Smiley-Webster score were evaluated. Computed tomography confirmed adequate screw placement. Follow-up ranged from 3 to 9 months. At 3-month follow-up, screw position and fusion across the fracture were evident in 87% of the cases treated with biplanar fluoroscopy and in 100% treated by iso-C. The average outcome score in the iso-C group was superior to that of the biplanar group (1.08 vs. 1.33, respectively), although not statistically significant. At last follow-up, the rate of successful fusion was 88% in the biplanar group and 95% in the iso-C group. Length of surgery was significantly lower in the iso-C group compared with the biplanar group (P=0.05). The significantly longer preparation time in the iso-C group (P=0.04) accounted for no overall difference in total operating room occupancy time between the 2 groups. Iso-C significantly decreased surgical time. At last follow-up iso-C assistance was associated with improved rates of radiographic fusion with comparable outcome and complication profiles. This series represents the largest cohort of patients treated with intraoperative real-time navigation assistance for odontoid fractures.

Endoscopic Endonasal Removal of a Large Petrous-Apex Epidermoid Tumor With Clival Involvement and Intradural Invasion

: Introduction: Epidermoid tumors comprise 1% of intracranial tumors. Although reported, intraosseous epidermoid tumors are even more rare. Cystic lesions of the petrous apex are uncommon and surgically challenging; the most rare pathology is presumed to be epidermoid.\r\nCase Presentation: This is a case of a 61-year-old woman with a large skull-base tumor extending inferiorly from the C1-C2 articulation and superiorly to the tuberculum sella. The lesion replaced the left-sided petrous apex, and the lateral extension of the tumor reached the styloid process. The tumor displayed intradural invasion medial to the internal auditory meatus, producing an intra-axial mass at the level of the upper pons. The patient presented with a 4-month history of headache and total unilateral deafness. Under image guidance, an endoscopic endonasal approach was used to totally resect the tumor. By following the tumor’s dural defect, the intra-axial part of the tumor was safely resected, and the dural defect was successfully repaired. \r\nConclusions: Image-guided endoscopic endonasal surgery is a versatile approach that can safely and easily address a large epidermoid tumor in this challenging region, obviating the need for demanding and sophisticated transcranial surgery.

Early descriptions of Grisel's syndrome

Dear Editor: We read with great interest the comprehensive review paper of Osiro et al. presenting Grisel's syndrome [1]. Apart from the introduction of this rare syndrome, the authors discussed recent developments on the pathogenesis of the syndrome along with treatment options. In the introduction, Sir Charles Bell (1774–1842 CE) was introduced as the first to explain nontraumatic atlantoaxial subluxation due to pharyngitis which ultimately led to death of the patient from spinal cord compression [1, 2]. Grisel's syndrome was named after Pierre Grisel (1869–1959 CE), a French surgeon who described the syndrome characterized by dislocation of the C1–C2 joint mostly in patients with pharyngitis and torticollis [1, 3]. Based on the historical evidence, we believe that the syndrome was known to the Greek and Persian physicians much earlier than thought. Among the ancient Greek scholars, Aetius of Amida (fifth–sixth century of the Common Era) seems to be the first to indicate the association between inflammation of the vertebrae caused by retropharyngeal abscess and vertebral luxation in his section on diphtheria [4]. The syndrome was later described by Rhazes (865–925 CE) in his Kitab al-Hawi (Liber Continens) quoting from Hippocrates' Of The Epidemics [5]. In the tenth century of the Common Era, Akhawayni Bukhari (Fig. 1), a prominent Persian physician, compiled the oldest extant treatise on medicine in new Persian, Hidayat al-Muta`allemin fi al-Tibb (The Students' Handbook of Medicine) [6, 7]. Being relatively short and simplified, the Hidayat was dedicated to the author's son and other students of medicine [8]. The second part of the book contains a chapter on the diphtheria describing different etiologies of suffocation, with a particular emphasis on a complication associated with neck pain and anterior subluxation of the cervical vertebrae. In addition to his description of this clinical entity, Akhawayni recommends novel life-saving approaches to the disease. Briefly, he advised application of either tongs or especially designed reins for applying pressure to reduce the subluxated vertebra [9]. The disease appears in the medical writings of the following centuries such as Avicenna's The Canon of Medicine and Jorjani's The Treasure of Khwarazm Shah, none of which have discussed the disease as detailed and instructive as that of Akhawayni's [10–12]. Altogether, descriptions of Grisel's syndrome and its associated symptoms are not limited to the recent centuries and date back to the earlier periods. S. E. J. Golzari Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

Larsen Syndrome With C3–C4 Spondyloptosis and Atlantoaxial Dislocation in an Adult

This is a clinical case report with a review of relevant literature. To describe a case of Larsen syndrome with C3-C4 spondyloptosis and atlantoaxial dislocation in a middle-aged female patient and to discuss management strategies. Spondyloptosis of the cervical spine is relatively rare and is caused by trauma, destruction of the vertebral bodies by tumors, or tuberculosis. Such gross vertebral displacement is usually associated with significant neurological deficits. Larsen syndrome is characterized by multiple joint displacements and can, very rarely, be associated with nontraumatic spondyloptosis of the cervical vertebra. A single case report of C1-C2 joint laxity causing atlantoaxial dislocation in a patient with Larsen syndrome is available in literature. No reports of any patient (with Larsen syndrome or nonsyndromic) who had both cervical spondyloptosis and atlantoaxial dislocation are available in literature. A 36-year-old female presented with chronic neck pain, bilateral hand deformity, and mild spasticity involving all 4 limbs. Cervical radiograph, computed tomographic scan, and magnetic resonance image revealed C3-C4 spondyloptosis and atlantoaxial dislocation. A combined ventral decompression of subaxial spine and instrumentation from C2 to C5, followed by posterior C1-C2 distraction arthroplasty and lateral mass stabilization of the subaxial spine up to C6, was done. The cervical deformity was corrected, and the patient remains symptom free. Patients with spondyloptosis of the cervical spine can rarely present with chronic neck pain and minimal neurological deficits. An additional pathology, such as atlantoaxial dislocation, can add to the complexity. Circumferential stabilization and fusion would be required in such cases to achieve a good outcome. Larsen syndrome is a rare cause of nontraumatic cervical displacements.