C1-C2 Facet Joint Research Articles

C1-C2 Facet Joint Penetration by C2 Pedicle Screws: Influence of Local Anatomy, Bone Mineral Density, and Screw Length.

A challenge of C2 pedicle screw placement is to avoid penetration into the C1-C2 facet joint, as this may alter normal biomechanics and accelerate joint degeneration. Our objective was to clarify how local anatomy and surgical technique may relate to C2 pedicle screw penetration into the C1-C2 facet joint. C2 pedicle screws were inserted using a fluoroscopically assisted freehand technique. Independent fellowship-trained spine surgeons blindly reviewed intraoperative fluoroscopic and postoperative computed tomography (CT) images for evidence of facet joint penetration (FJP). C2 pedicle morphometry, the sagittal angle of the facet joint, axial and sagittal pedicle screw angles, and screw length were measured on the relevant CT images. A total of 34 patients fulfilled the study criteria, and a total of 68 C2 pedicle screws were placed. Eight screws (16%) penetrated the C1-C2 facet joint. The mean sagittal angle of the C1-C2 facet joint was significantly lower in the FJP group compared with the non-FJP group. The mean sagittal angle of the screws was significantly higher in the FJP group compared with the non-FJP group. The mean screw length was significantly greater for screws causing FJP compared with the non-FJP group. The mean axial screw angle was significantly lower in the FJP group compared with the non-FJP group. Pedicle width, length, height, and transverse angle were not significantly associated with FJP. Independent reviewers were able to identify FJP on intraoperative fluoroscopic imaging in 2 out of 8 cases. Lower sagittal angle of the facet joint, higher sagittal angle of the pedicle screw, and screw length >24 mm are associated with higher risk of C1-C2 FJP. When placing C2 pedicle screws under these conditions, caution should be taken to avoid FJP. Several anatomical and technical factors may increase the risk of C1-C2 FJP during placement of C2 pedicle screws using a fluoroscopically assisted freehand technique, underscoring the importance of preoperative planning and limiting screw length.

Indirect Ventral Brainstem Decompression by Posterior C1-C2 Distraction and Fixation for Basilar Invagination

Basilar invagination usually shows a decrease of clivus axis angle (CAA), which could give rise to progressive neural compression. Exploring a safe and effective fixation technique to achieve atlantoaxial stability and neural decompression remains necessary. In this study, we introduce a modified posterior C1-C2 distraction and fixation technique by which we obtained indirect ventral neural decompression and atlantoaxial stability in a series of patients with decreased CAA. Thirty patients of basilar invagination were enrolled in our series. All patients underwent thin-slice computed tomography (CT) scan, magnetic resonance imaging, and dynamic plain radiography examinations before surgery, at discharge and during the follow-ups. Posterior C1-C2 facet joint release and intraoperative reduction by fastening rods were performed in all patients. The CAA was measured on midsagittal CT scans. Patients' neurologic status was evaluated by the Japanese Orthopaedic Association score. No neurovascular injury and serious postoperative complication occurred in all patients. Complete ventral brainstem decompression was achieved in 20 patients and partial in 10 patients. The mean postoperative CAA significantly improved to 132.6 degrees compared with the preoperative 123.6 degrees (P < 0.01). The bone fusion was confirmed in all patients on the basis of the last follow-up spine CT scans. Indirect ventral brainstem decompression by posterior C1-C2 distraction and fixation is a safe and effective technique for treatment of basilar invagination.

Outcome of Surgery for Congenital Craniovertebral Junction Anomalies with Atlantoaxial Dislocation/Basilar Invagination: A Retrospective Study of 94 Patients

To evaluate the results of surgery for congenital craniovertebral junction (CVJ) anomalies with atlantoaxial dislocation (AAD)/basilar invagination (BI) and compare the results of transoral odontoidectomy and posterior fusion (TOO+PF) with only posterior fusion (PF) in patients with irreducible AAD/BI. All 94 patients with congenital CVJ anomalies with AAD/BI operated on during the 3-year study period (June 2013-May 2016) were included. Of these patients, 55 had irreducible AAD/BI and the remaining 39 had reducible AAD/BI. TOO+PF was restricted to patients (34/94; 36.2%) with irreducible AAD/BI when reduction and realignment by intraoperative C1-C2 facet joint manipulation were considered technically difficult and risky. The remaining patients with irreducible AAD/BI and all the patients with reducible AAD/BI (60/94; 63.8%) were managed with only posterior fusion. Poor preoperative Nurick grade, preoperative dyspnea/lower cranial nerve deficits, and syringomyelia were associated with significantly higher incidence of postoperative pulmonary complications. Follow-up ≥3 months (final follow-up) was available for 87 patients. Good outcome (Nurick grade 0-3) at final follow-up was noted in 90% (45/50) of the patients with irreducible AAD/BI and 91.9% (34/37) of the patients with reducible AAD/BI. Preoperative poor Nurick grade (4-5) was the only factor associated with poor outcome. No significant difference in perioperative complications, outcome, and fusion was noted between patients who underwent TOO+PF or only PF for irreducible AAD/BI. Many of the patients with congenital AAD/BI showed remarkable recovery after surgery. Preoperative poor Nurick grade (4-5) is associated with poor outcome. TOO+PF is a safe alternative treatment option for irreducible AAD/BI when only PF techniques are technically difficult/risky.

Endoscopic single stage trans-oral decompression and anterior C1 lateral mass and C2 pedicle stabilization for atlanto-axial dislocation.

Although most of the cases of atlanto-axial dislocation (AAD) and basilar invasion can be managed by posterior approaches in the recent times, anterior decompression with stabilization is required in selected patients who persist with irreducible AAD even after manipulation of the C1-C2 facet joint under general anesthesia. A single stage endoscopic trans-oral decompression and stabilization can be used in such patients. It has not been described so far to the best of authors' knowledge. This is indicated in irreducible AAD with the mandibular angle lying below the C2-C3 disc space. It is not a proper choice when the mandibular angle is above the C2-C3 disc space, there is involvement of the facet joint by trauma or any other pathologies, and if a posterior compression at the cervicomedullary junction persists. All patients should undergo pre-operative radiographs, computed tomography (CT) scan and magnetic resonance imaging with angiogram of the cranio-vertebral region. Utilizing this technique, an intra-operative satisfactory reduction of the dislocation with C1-C2 stabilization could be achieved in 3 patients, and 7 required an additional odontoid excision. Post- operative plain radiographs should be performed to assess for C1- C2 alignment and fusion at 3 and 12 months after surgery. All 10 patients of our series had an irreducible AAD and two had an additional basilar invasion. All patients improved from the pre-operative Ranawat grade 3A (n = 8) and 3B (n = 2) to post-operative grade 1 (n = 9) and 2 (n = 1) at a 3-12- month follow-up assessment. The average duration of the procedure and blood loss was 145 minutes and 75 ml, respectively. Endoscopic trans-oral single stage decompression and stabilization seems to be an effective and safe alternative in selected patients with AAD and basilar invasion.

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 &amp; 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 &amp; 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 &amp; 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.

Distraction Arthrodesis of the Atlantoaxial Facet Joint with Preservation of the C2 Root for the Management of Intractable Occipital Neuralgia Caused by C2 Root Compression

Introduction Vertical collapse of the C1-C2 facet joint may cause narrowing of the C2 root foramen with root compression, resulting in severe occipital neuralgia. The purpose of this study was to evaluate the prospectively collected outcomes data of a distraction arthrodesis surgical group (Study group) in comparison to a Control group in a non-randomized design. Material and Methods The Study group underwent intraoperative skeletal traction, preservation of the C2 nerve roots, facet joint distraction and insertion of a bone block and cancellous bone into the joint along with posterior fusion, and segmental screw fixation using posterior C1 arch screws instead of lateral mass screws. The Control group had C2 root transection with C1-C2 segmental screw fixation and arthrodesis. Inclusion criteria for both groups were (1) occipital neuralgia caused by C2 root compression confirmed by clinical manifestation and imaging studies including radiographs, CT scan, and MRI, (2) intractable pain (VAS≥7) unresponsive to nonoperative treatment, and (3) follow-up period ≥12 months. We compared the preoperative and postoperative 10-point VAS scores for occipital neuralgia and neck pain; NDI; and JOA scores and recovery rates. Results There were 15 patients in the Study group and 8 in the Control group. All had facet joint destruction and/or collapse caused by underlying disorders including rheumatoid arthritis (Study group: 5 ; Control group: 3), rheumatoid arthritis with odontoid nonunion (2, 0), odontoid nonunion (3, 1), unifacet spondylosis (3, 2), os odontoideum (2, 1), and cerebral palsy (0, 1). There was no significant difference in age (61 ± 6, 62 ± 9), gender (4 and 3 men, respectively), and the number of cases with accompanying myelopathy (5, 2) between the 2 groups. The follow-up period averaged 21 ± 12 versus 33 ± 25 months, respectively. There was no significant difference in the VAS score for the preoperative occipital neuralgia (8.2 ± 0.9, 7.9 ± 0.6, p = 0.39). However, it was significantly lower in the Study group at 1, 3, 6, and 12 months postoperatively (p = &lt;0.01, respectively). At 12 months, the VAS was 0.4 ± 0.6 versus 2.5 ± 2.6 ( p = 0.01). In the Study group, all patients had little or no pain (VAS ≤2) while 2 patients (25%) in the Control group were still on medication (Gabapentin) with moderate to severe pain (VAS 4 and 8 respectively). There was no significant difference in preoperative and postoperative VAS scores for neck pain, NDI, and JOA scores and recovery rate, since these values are minimally influenced by occipital neuralgia. Conclusion Our results suggest that our novel technique of distraction arthrodesis can be an effective option for the management of intractable occipital neuralgia caused by C2 root compression. Prospective randomized studies are required for better evaluation.

Neck-Tongue Syndrome.

Neck-tongue syndrome (NTS) is a headache disorder often initiated by rapid axial rotation of the neck resulting in unilateral neck and/or occipital pain and transient ipsilateral tongue sensory disturbance. In this review, we examine reported cases of NTS since its initial description in 1980 to highlight the significance of this condition in the differential diagnosis of headache in patients presenting with neck pain and altered tongue sensation. The anatomical basis of NTS centers on the C1-C2 facet joint, C2 ventral ramus, and inferior oblique muscle in the atlanto-axial space. NTS may be categorized as complicated (secondary to another disease process) or uncomplicated (hereditary, related to trauma, or idiopathic). Diagnosis is based on clinical suspicion after a thorough history and physical without a pathognomonic radiologic finding. It is typically treated conservatively with medications, local injections, immobilization with cervical collars, or physical therapy; rarely is surgical intervention pursued.

Modified technique of transoral release in one-stage anterior release and posterior reduction for irreducible atlantoaxial dislocation

BackgroundOne-stage anterior release and posterior reduction is one of the most effective methods for irreducible atlantoaxial dislocation. However, the criteria of appropriate tissue release for successful posterior reduction is yet to be confirmed. Hence, an assistant technique using the transoral approach to verify satisfactory release is required. To evaluate the efficacy of the modified technique of transoral release for irreducible atlantoaxial dislocation (IAAD) with patients underwent one-stage anterior release and posterior reduction. MethodsBetween January 2009 and June 2014, 23 consecutive patients diagnosed with IAAD free from bony union between the C1–C2 facet joints on reconstructive computed tomography scan underwent one-stage anterior release and posterior reduction after no response to 2 weeks of skull traction. During transoral release, an elevator was used as a lever repeatedly to confirm a 3–5 mm bilateral joint space between the lateral masses of the atlas and axis. The release was accomplished since a 3–5 mm joint space was achieved. After anterior release, posterior reduction and instrumented fusion were subsequently performed. ResultsAll patients were observed for an average of 18 (range 6–50) months. Nineteen of 23 patients achieved complete reduction while four had an incomplete reduction. Significant differences in pre- and postoperative JOA scores and cervicomedullary angle (CMA) were found. Twenty-one patients presenting with myelopathy had a JOA score of 12.9 at final follow-up, improved from 7.8 before surgery. The mean CMA improved to 143.5° postoperatively from 101.8° preoperatively. Bony fusion was confirmed in all cases under radiologic assessment during follow-up; there were no instrument failures. ConclusionThe modified technique of transoral release provides appropriate criteria for anterior release, to achieve good posterior reduction without excessive tissue release or intraspinal manipulation, proving its value as an assistant technique in one-stage anterior release and posterior reduction for IAAD.

Distraction Arthrodesis of the C1-C2 Facet Joint with Preservation of the C2 Root for the Management of Intractable Occipital Neuralgia Caused by C2 Root Compression.

Prospective observational cohort study. To compare the outcomes of our new technique, distraction arthrodesis of C1-C2 facet joint with C2 root preservation (Study group), to those of conventional C1-C2 fusion with C2 root transection (Control group) for the management of intractable occipital neuralgia caused by C2 root compression. We are not aware of any report concerning C2 root decompression during C1-C2 fusion. Inclusion criteria were visual analogue scale (VAS) score for occipital neuralgia 7 or more; C2 root compression at the collapsed C1-C2 neural foramen; and follow-up 12 months or more. The Study group underwent surgery with our new technique including (1) C1-C2 facet joint distraction and bone block insertion while preserving the C2 root; and (2) use of C1 posterior arch screws instead of conventional lateral mass screws during C1-C2 segmental screw fixation. The Control group underwent C2 root transection with C1-C2 segmental screw fixation and fusion. We compared the prospectively collected outcomes data. There were 15 patients in the Study group and 8 in the Control group. Although there was no significant difference in the VAS score for the occipital neuralgia between the 2 groups preoperatively (8.2 ± 0.9 vs. 7.9 ± 0.6, P = 0.39), it was significantly lower in the Study group at 1, 3, and 6 months postoperatively (P < 0.01, respectively). At 12 months, it was 0.4 ± 0.6 versus 2.5 ± 2.6 (P = 0.01). There was no significant difference in improvement in the VAS score for neck pain and neck disability index and Japanese Orthopedic Association recovery rate, which are minimally influenced by occipital neuralgia. Our novel technique of distraction arthrodesis with C2 root preservation can be an effective option for the management of intractable occipital neuralgia caused by C2 root compression.

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.

Atlantoaxial instability in acute odontoid fractures is associated with nonunion and mortality

Background contextOdontoid fractures are the most common geriatric cervical spine fractures. Nonunion rates have been reported to be up to 40% and mortality up to 35%, and poor functional outcomes are common. Atlantoaxial instability (AAI) is a plausible prognostic factor, but its role has not been previously examined. PurposeTo determine the effect of severe AAI on the outcomes of nonunion and mortality in patients with acute odontoid fractures. Study designRetrospective cohort/single institution. Patient sampleOne hundred twenty-four consecutive patients with acute odontoid fractures. Outcome measuresRates of nonunion and mortality. MethodsTwo independent blinded reviewers measured AAI using postinjury computed tomography scans. Patients were classified as having “severe” or “minimal” AAI on the basis of greater versus less than or equal to 50% mean subluxation across each C1–C2 facet joint. Rates of nonunion and mortality were compared using independent samples t tests and adjusted for age, displacement, and subtype using binary logistic regression. ResultsOne hundred seven patients had minimal AAI and 17 had severe AAI. Mean follow-up was 4.4 months (standard deviation=4.6). Patients with severe AAI were more likely to experience nonunion (29% vs. 10%, respectively; p=.03) and mortality (35% vs. 14%, respectively; p=.03) regardless of treatment modality. Fracture displacement correlated with AAI (r2=0.65). When adjusted for patient age, the odds ratio of nonunion with severe AAI approached significance at 3.3 (95% confidence interval [CI]: 0.9–11.7). Mortality prediction with AAI approached a twofold increased risk (odds ratio=2.1; 95% CI: 0.6–6.8). In patients with Type-II fractures, the odds of mortality with severe AAI approached a threefold higher risk (odds ratio=3.3; 95% CI: 0.9–12.3). ConclusionsPatients with acute odontoid fractures and severe AAI may be more likely to experience nonunion and mortality, suggesting the possibility that aggressive management could be warranted. Further investigation with a large prospective study including patient-important functional outcomes is justified.

Minimally Invasive Revision of a C2 Isthmus Screw

We present a novel technique for minimally invasive revision of a cervical isthmic screw via two 18-mm transmuscular tubular accesses. A 55 year old male with combined anterior and posterior instrumentation after corpectomy of C3 to C4 complained of persistent neck pain and reduced head mobility in the follow-up examination. Isthmic screws had been placed in C2 and pedicle screws in C5. The system used is a versatile modular screw-rod system for the fixation of the occipito-cervico-thoracic spine. The patient's complaints were attributed to an inappropriately placed C2 isthmus screw. The screw was approximately 3 mm too long and perforated the C1-C2 facet joint on the left side. We replaced the screw by a shorter one through a minimally invasive transmuscular tubular approach. The transmuscular tubular access offered an adequate exposure of the screw head. The special features of the versatile modular fixation device allowed for screw easing, removal, replacement, and tightening through the tube. The symptoms of the patient resolved completely. Intraoperative blood loss and postoperative approach-associated pain were negligible. We conclude that in case of dorsal cervical fixation with a versatile modular screw-rod system, a minimally invasive transmuscular approach for revision of an isthmic screw may be a good alternative to open surgery.

The Effect of Soft-Tissue Restraints After Type II Odontoid Fractures in the Elderly

A biomechanical analysis of soft-tissue restraints to passive motion in odontoid fractures. To quantify the role of the C1-C2 facet joint capsules and anterior longitudinal ligaments (ALLs) in the setting of a type II odontoid fracture in the elderly. The odontoid process itself is the primary stabilizer at the C1-C2 level; however, little is known about the role of the soft-tissue structures that remain intact in the setting of an odontoid fracture after a low-energy mechanism. Ten cadaveric C0-C2 spinal segments were studied. Specimens were tested under simulated axial rotation with an applied moment of ±1 Nm and with an application of a 10 N anteriorly directed force to the body of C2 to induce sagittal translation. Optical motion data were initially collected for the intact state and after a simulated dens fracture. The specimens were then divided into 2 groups, where 1 group underwent unilateral and then bilateral C1-C2 facet capsular injuries followed by an ALL injury. The second group underwent the ALL injury before the same capsular injuries. Changes in axial range of motion and C1-C2 translation were analyzed using 2-way repeated measures analyses of variance and post hoc Student-Newman-Keuls tests (α = 0.05). In axial rotation, there was an increase in range of motion by approximately 13%, with the fracture of the dens compared with the intact state (P < 0.05). An increase was also present for each subsequent soft-tissue injury state compared with the previous (P < 0.05); however, there was no difference found between the 2 sectioning protocols. For sagittal translation testing, it was found that the odontoid fracture alone showed an increase of 3 mm of C1-C2 translation compared with intact (P < 0.05). Further soft-tissue injuries did not show an increase until the complete injury state. This study identifies that type II odontoid fractures without associated soft-tissue injury may be stable under certain loading modes.

A fourth atlantoaxial joint: an initial description

Background contextThe presence of a supernumerary posterior atlantoaxial facet joint has not been reported in the literature. PurposeTo describe a patient who presented with a unilateral anomalous posterior facet joint and discuss its possible embryological origin. Study design/settingCase report. MethodsA 35-year-old woman presented with severe neck pain, headaches, and tingling radiating down her left arm. Radiological studies showed an anomalous right C1–C2 facet joint causing dorsal compression of the spinal cord and cord compression secondary to a C5–C6 herniated disc. The patient underwent resection of the abnormal facet via a posterior approach followed by anterior cervical discectomy and fusion at C5–C6. ResultsThe patient reported marked improvement in her neck pain and partial improvement in her left upper extremity numbness and tingling. Postoperative radiographs showed no abnormal motion at C1–C2. ConclusionsThe authors hypothesize that, in this patient, the C1 and C2 sclerotomes may have fused abnormally posteriorly, followed by the initiation of events at this site that eventually led to the formation of a morphologically normal synovial joint in an abnormal location.

It Is Time to Abandon Atlanto-Axial Joint Injections: Do No Harm!

It Is Time to Abandon Atlanto-Axial Joint Injections: Do No Harm!

Posterior Circulation Stroke after C1–C2 Intraarticular Facet Steroid Injection: Evidence for Diffuse Microvascular Injury

Posterior Circulation Stroke after C1–C2 Intraarticular Facet Steroid Injection: Evidence for Diffuse Microvascular Injury

Poster 268: The Role of Cervical C1/2, C2/3 Spinal Injections in the Diagnosis of Cervicogenic Headache

Objective: The diagnosis and treatment of cervicogenic headache (CEH) is challenging. This study was to determine the role of C1-C2 and C2-C3 facet joint and dorsal ramus injections in diagnosis of CEH. Design: Retrospective study. Setting: Academic pain center. Participants: 30 patients with clinical diagnosis of CEH, 13 men and 17 women; mean age of 42 years (range, 18–65y). All patients had failed multiple pharmacologic and other treatments prior to the study. Average disease duration was 6.9 (0.5–20) years.

MR morphology of alar ligaments and occipitoatlantoaxial joints: study in 50 asymptomatic subjects.

To assess the magnetic resonance (MR) imaging appearance of the alar ligaments and joints in the upper cervical spine to determine the prevalence of structural alterations in asymptomatic individuals. Fifty healthy individuals (31 men, 19 women) with a mean age of 30 years (range, 19-47 years) underwent coronal T1- and T2-weighted and transverse T1-weighted MR imaging. MR findings were analyzed independently by two musculoskeletal radiologists, with disagreements resolved in conference. Alar ligaments were detected in 42 (84%) (left side) and 38 (76%) (right side) of 50 individuals. The majority of ligaments (88%) and joints (58%) of the craniocervical junction (CCJ) were asymmetric. Asymmetry of the joint between C1 and C2 was less frequent (46%). Small amounts of fluid were detected in 8% of CCJ joints and 56% of C1-C2 joints in asymptomatic individuals. Asymmetry of alar ligaments, CCJ and C1-C2 facet joints, and joint effusions are common in asymptomatic individuals. The clinical relevance of these MR findings is therefore limited in the identification of the source of neck pain in symptomatic patients.

Sensory innervation of the cervical facet joints in rats.

With a retrograde neurotracing method with Fluoro-Gold (FG; Fluorochrome, Denver, CO), the level of dorsal root ganglions (DRGs) innervating the C1-C2, C3-C4, and C5-C6 facet joints and their pathways were investigated in rats. To clarify the levels of DRGs and parasympathetic nodose ganglions innervating the cervical facet joints and to determine the pathways from the facet joint to DRGs. Patients with cervical facet lesions and whiplash sometimes experience diffuse neck pain, headache, arm, and shoulder pain, but the pattern of sensory innervation of the facet joint is still unclear. Sixty male Sprague-Dawley rats were used. Fluoro-gold crystals (FG) were applied into the C1-C2 (C1-C2 group), C3-C4 (C3-C4 group) and C5-C6 (C5-C6 group) facet joints, and numbers of the labeled neurons in DRGs from C1 to T5 and nodose ganglions were determined. To determine the sensory pathway, bilateral sympathectomy was performed. Neurons labeled with FG were present in the DRGs from C1 through C8 in the C1-C2 group, from C1 to T2 in the C3-C4 group, and from C3 to T3 in the C5-C6 group without sympathectomy. In the nodose ganglions, 17 FG-labeled neurons were present. The number of the labeled neurons after sympathectomy was not significantly different in the C1, C2, and C3 DRGs in the C1-C2 group, in the C3 and C4 DRGs in the C3-C4 group, and in the C5 and C6 DRGs in the C5-C6 group from that in the groups without sympathectomy. In contrast, the number of labeled neurons in the DRGs was significantly less at the other levels than that in the groups without sympathectomy (P < 0.01). Sensory nerve fibers of the cervical facet joint were derived from the C1-T3 DRGs. Some sensory nerves from the cervical facet joint entered the paravertebral sympathetic trunks and reached the DRGs at multisegmental levels. The present findings regarding the multisegmental innervation to the facet joint may be of importance in the treatment of facet joint syndrome.