Proposal of New Radiological Classification and Treatment Strategy for Transverse Fractures of the C2 Axis Body.

OBJECTIVE: To investigate the characteristics of transverse fractures of the C2 axis body diagnosed on sagittal computed tomography (CT) and to propose new classification and appropriate treatment strategies. METHODS: A retrospective study was performed by enrolling 49 patients (26 men and 23 women) with transverse fractures of the C2 axis body who were treated at four national trauma centers of tertiary university hospitals from January 2000 to December 2017. The mean age of the patients was 60.8 years (ranging from 21 to 90 years). We classified 49 transverse fractures of the C2 body into three types based on fracture trajectories involving superior articular facet (SAF) and lateral cortex (LC) of the C2 body on coronal CT as follows: Type 1, involvement of C2 SAF on both sides; Type 2, unilateral involvement of C2 SAF on one side and LC on the other side; Type 3, involvement of LC on both sides. The characteristics, treatment methods, and results of 49 transverse fractures of the C2 body were analyzed. Mean follow-up was 12.6 months (ranging from 12 to 26 months). RESULTS: Twenty-six (53.1%) patients were Type 1, 21 (42.9%) were Type 2, and 2 (4.0%) were Type 3. Correlation coefficients for intra-observer and inter-observer reliabilities of classification were 0.723 and 0.598 (both, P < 0.001), respectively. About 40.8% (7 Type 1 and 13 Type 2) of the patients had fracture displacement >3 mm; Incidence of fracture displacement >3 mm was higher in Type 2 than Type 1 (61.9% vs 26.9%, P < 0.05). About 79.6% (20 Type 1, 17 Type 2 and 2 Type 3) of the patients were treated conservatively, and 20.4% (6 Type 1 and 4 Type 2) underwent surgery. At last follow-up, 47 out of 49 patients achieved fusion; overall fusion rate was 95.9%. All conservatively treated Type 1 and Type 3 patients achieved fusion. Out of 17 conservatively treated Type 2 patients, 15 achieved fusion but two developed nonunion; however, two nonunion patients opted not to undergo surgery. Subgroup analysis showed that Philadelphia brace caused nonunion significantly in fracture displacement >3 mm compared to Minerva brace/Halovest (100% vs 0%, P < 0.05). All surgically treated Type 1 and 2 patients achieved fusion. In terms of clinical outcomes, neck pain visual analog scale and neck disability index were significantly improved (both, P < 0.01). According to Odom's criteria, 93.9% (46/49) of the patients achieved satisfactory outcomes. No major complications occurred. CONCLUSIONS: The majority of transverse fractures of C2 body can be treated conservatively. However, surgery or rigid Minerva brace/Halovest should be considered for Type 2 transverse fractures of the C2 body with fracture displacement >3 mm.

Biologic Agents Preserve the C-2 Pedicle in Patients with Rheumatoid Arthritis: A Comparative Imaging Study Using Three-Dimensional Computed Tomography.

OBJECTIVE: To investigate whether biologic agents (BAs) reduce a narrow C-2 pedicle screw trajectory, which is often a key stabilizer in surgical treatment, in patients with rheumatoid arthritis (RA). METHODS: A total of 100 patients with RA treated with and without BAs (BA [+] group [n = 50] and BA [-] group [n = 50]), respectively, were included in the present study. Computed tomography (CT) images of their cervical spine, including C-2, were analyzed. The maximum screw diameter at C-2 that could be inserted without breaching the cortex, measured on 3-dimensional images using a CT-based navigation system, was compared between the groups with and without BA administration. Furthermore, the destruction of the atlantoaxial joint was examined using CT images. The risk factors for a narrow C-2 pedicle were elucidated among the patients treated with BAs. RESULTS: The pedicle in the BA (+) group had a significantly larger C-2 maximum screw diameter than the BA (-) group (6.00 mm vs. 5.13 mm, P < 0.001), with less destruction of the atlantoaxial joint. Among the BA (+) group, a longer period until the initial administration of BAs and RA disease duration were associated with a narrow C-2 pedicle. CONCLUSIONS: This study suggests that BAs can maintain the trajectory for C-2 pedicle screws, which acts as a key stabilizer in surgical management for the rheumatoid cervical spine, by halting the destruction of the atlantoaxial joint. Early introduction of BAs can be especially important to prevent the narrowing of the C-2 pedicle.

Chondrosarcoma in the body of the C2 vertebral axis.

Chondrosarcoma, a malignant bone tumor, is rarely encountered in the cervical spine. This article describes a patient whose neck pain and dysphagia were caused by an expansive, destructive lesion with calcification that was located in the body of the axis (C2 vertebra), the first time a chondrosarcoma has been reported in this location.

Os Odontoideum: Analysis of 190 Surgically Treated Cases.

OBJECTIVE: The aim of this study was to report an experience with 190 cases of os odontoideum over 20 years. The management outcome following atlantoaxial fixation was analyzed. METHODS: From January 2000 to September 2018, 190 patients with os odontoideum were surgically treated. There were 113 male patients and 77 female patients; average age was 24 years (range, 2-68 years).The patients were divided into 3 groups depending on the nature of atlantoaxial dislocation (group 1, mobile and partially or completely reducible atlantoaxial dislocation; group 2, fixed or irreducible atlantoaxial dislocation; group 3, presence of basilar invagination). There were 65 pediatric patients (<18 years old). All patients underwent atlantoaxial joint manipulation and lateral mass plate and screw fixation. The goal of surgery was segmental atlantoaxial arthrodesis. No transoral or posterior foramen magnum bone decompression was done. Occipital bone was not included in the fixation construct. RESULTS: On direct bone handling and observation, atlantoaxial joint pathologic hyperactivity related instability was identified in all patients. Atlantoaxial segmental stabilization resulted in clinical symptomatic and neurologic improvement in 100% of patients. CONCLUSIONS: Os odontoideum signifies chronic or long-standing atlantoaxial instability. Segmental atlantoaxial fixation is a reliable form of surgical treatment. Bone decompression is not necessary. Inclusion of occipital bone and subaxial vertebrae in the fixation construct is not necessary.

The Rare Anomaly That Can Be Confused With Fracture: Os Odontoideum.

Os odontoideum is a rare anomaly of the second cervical vertebra. The odontoid process is separated by a wide gap from the vertebral body in this anomaly. It can be associated with atlantoaxial instability.

Surgical Fixation Using Screw-Rod Construct Instrumentation for Upper Cervical Instability in Pediatric Down Syndrome Patients.

STUDY DESIGN: Retrospective case series. OBJECTIVES: To describe the indications and outcomes of cervical fixation using modern instrumentation in a case series of pediatric Down syndrome (DS) patients. SUMMARY OF BACKGROUND DATA: Cervical instability is the major cervical spine concern in children with DS. Although fixation techniques have advanced over the past quarter-century, the outcome of fixation with modern instrumentation for upper cervical instability in DS patients has not been thoroughly investigated. METHODS: We searched the orthopedic database at our institution for patients with a diagnosis of DS who had undergone a cervical spine fusion between 2006 and 2017. Patient demographics, diagnoses, surgical indications, surgical details, and complications were recorded. Preoperative imaging was reviewed to determine atlanto-dens intervals and spinal cord signal changes. Postoperative radiographs or CT scans were reviewed to determine union. RESULTS: Twelve DS patients met our inclusion criteria. The mean age at surgery was 9.3 years (range 3.8-18.8 years). Patients with secondary causes of instability included 7 patients with os odontoideum and 1 patient with a pars fracture. Three patients (25%) were identified on asymptomatic screening, with none of these having cord signal changes on magnetic resonance imaging (MRI). Modern implants (screws, plates, cages) were used in every patient in our series. The mean number of levels fused was 1.9 (range 1-5). The overall complication rate was 41.7% (5/12). Four patients required repeat surgery for nonunion. All patients with adequate radiographic follow-up demonstrated union (11/11, 100%). One patient was lost to follow-up. CONCLUSIONS: Fixation for cervical instability is a critical component of the management of DS. A minority of patients receiving surgery were identified through asymptomatic screening. There was a high complication risk associated with surgery in our study; however, the addition of rigid fixation has lessened the complication rate compared with previous studies. LEVEL OF EVIDENCE: Level IV.

Atlanto-axial Pannus in Patients with and without Rheumatoid Arthritis.

OBJECTIVE: Pannus formation in the atlanto-axial joint is a well-recognized complication of rheumatoid arthritis (RA). Occasionally, atlanto-axial pannus is reported when patients without a history of RA undergo magnetic resonance imaging (MRI) of the cervical spine. We sought to further characterize these patients. METHODS: The Partners HealthCare Research Patient Data Registry was free-text searched for "atlanto-axial" AND "pannus" in cervical spine MRI reports from 2001 to 2015. Cases with MRI reports describing pannus were reviewed. Clinical data were extracted by chart review in cases with confirmed atlanto-axial pannus (n = 105). RESULTS: Twenty-nine patients (27.6%) had RA, all of whom except one carried this diagnosis at the time of the MRI scan. Only 1 of 77 patients without a history of RA was subsequently diagnosed with RA (1.3%, 95% CI 0.1-7.0%, median followup 3.6 yrs). Non-RA patients were significantly older (median age 79 vs 63 yrs, p < 0.0001), less frequently female (55% vs 86%, p = 0.0032), and more likely to have undergone prior cervical spine surgery (18% vs 0%, p = 0.016) compared with RA patients. Thirty-four non-RA patients (44.7%) either had a clinical diagnosis of calcium pyrophosphate dihydrate disease (CPPD) or imaging evidence for tissue calcification. There were no significant differences in age or sex between the CPPD subgroup and other non-RA patients. Twenty-eight patients (26.7%) underwent cervical spine surgery. CONCLUSION: Patients without RA diagnosis and incidental atlanto-axial pannus on cervical spine MRI are unlikely to have previously unrecognized RA. Degenerative disease and tissue calcification may contribute to pannus formation in these patients.

Auxiliary Wings of the Axis.

Bony anomaly of axis (C2) vertebra is well known. However, expansion of the posterior element is less documented. We describe a case of additional bony ring attached to the posterior spinous process in a 10-year-old male who presented with the complaint of progressive swelling at the upper cervical region. On physical examination a firm swelling approximately 8 × 5 cm was present at the back of the neck just below the hair line. There was no focal neurologic deficit. Computed tomography scan of the cervical spine showed an additional bony arch attached to the spinous process of the C2 vertebra. Magnetic resonance imaging revealed a soft tissue mass within the additional bony ring without involvement of neural structures. Complete surgical excision of the mass was done. Anomalous expansion of the spinous process of the C2 vertebra may remain silent. Surgery may be necessary for cosmetic purposes.

Insights into the Past and Future of Atlantoaxial Stabilization Techniques.

Over the past century, atlantoaxial stabilization techniques have improved considerably. To our knowledge there has been a scarcity of articles published that focus specifically on the history of atlantoaxial stabilization. Examining the history of instrumentation allows us to evaluate the impact of early influences on current modern stabilization techniques. It also provides inspiration to further develop the techniques and prevents repetition of mistakes. This paper reviews the evolution of C1-C2 instrumentation techniques over time and provides insights into the future of these practices.We did an extensive literature search in PubMed, Embase and Google Scholar, using the following search terms: 'medical history', 'atlantoaxial', 'C1/C2', 'stabilization', 'instrumentation', 'fusion', 'arthrodesis', 'grafting', 'neuroimaging', 'biomechanical testing', 'anatomical considerations' and 'future'.Many different entry zones have been tested, as well as different constructs, from initial attempts with use of silk threads to use of hooks and rod-wire techniques, and handling of bone grafts, which eventually led to the development of the advanced screw-rod constructs that are currently in use. Much of this evolution is attributable to advancements in neuroimaging, a wide range of new materials available and an improvement in biomechanical understanding in relation to anatomical structures.

Efficacy and Safety of Ixekizumab in the Treatment of Radiographic Axial Spondyloarthritis: Sixteen-Week Results From a Phase III Randomized, Double-Blind, Placebo-Controlled Trial in Patients With Prior Inadequate Response to or Intolerance of Tumor Necrosis Factor Inhibitors.

OBJECTIVE: To investigate the efficacy and safety of ixekizumab in patients with active radiographic axial spondyloarthritis (SpA) and prior inadequate response to or intolerance of 1 or 2 tumor necrosis factor inhibitors (TNFi). METHODS: In this phase III randomized, double-blind, placebo-controlled trial, adult patients with an inadequate response to or intolerance of 1 or 2 TNFi and an established diagnosis of axial SpA (according to the Assessment of SpondyloArthritis international Society [ASAS] criteria for radiographic axial SpA, with radiographic sacroiliitis defined according to the modified New York criteria and ≥1 feature of SpA) were recruited and randomized 1:1:1 to receive placebo or 80-mg subcutaneous ixekizumab every 2 weeks (IXEQ2W) or 4 weeks (IXEQ4W), with an 80-mg or 160-mg starting dose. The primary end point was 40% improvement in disease activity according to the ASAS criteria (ASAS40) at week 16. Secondary outcomes and safety were also assessed. RESULTS: A total of 316 patients were randomized to receive placebo (n = 104), IXEQ2W (n = 98), or IXEQ4W (n = 114). At week 16, significantly higher proportions of IXEQ2W patients (n = 30 [30.6%]; P = 0.003) or IXEQ4W patients (n = 29 [25.4%]; P = 0.017) had achieved an ASAS40 response versus the placebo group (n = 13 [12.5%]), with statistically significant differences reported as early as week 1 with ixekizumab treatment. Statistically significant improvements in disease activity, function, quality of life, and spinal magnetic resonance imaging-evident inflammation were observed after 16 weeks of ixekizumab treatment versus placebo. Treatment-emergent adverse events (AEs) with ixekizumab treatment were more frequent than with placebo. Serious AEs were similar across treatment arms. One death was reported (IXEQ2W group). CONCLUSION: Ixekizumab treatment for 16 weeks in patients with active radiographic axial SpA and previous inadequate response to or intolerance of 1 or 2 TNFi yields rapid and significant improvements in the signs and symptoms of radiographic axial SpA versus placebo.

Delayed Recurrent Laryngeal Nerve Palsy Following Anterior Cervical Discectomy and Fusion.

BACKGROUND: Vocal cord dysfunction resulting from recurrent laryngeal nerve palsy (RLNP) is a known complication following anterior cervical discectomy and fusion. RLNP occurs typically secondary to neurapraxia caused by intraoperative compression or traction on the nerve and less commonly from direct nerve injury intraoperatively in the setting of anterior cervical spine surgery. Patients with RLNP typically present with hoarseness immediately after surgery owing to unilateral vocal cord paralysis. In rare cases, there is late-onset, progressive development of RLNP that may potentially lead to permanent vocal cord paralysis or respiratory failure. CASE DESCRIPTION: A 75-year-old woman presented with myeloradiculopathy and chronic urinary incontinence. Imaging showed severe foraminal and central stenosis with T2 cord signal change. A C4-7 anterior cervical discectomy and fusion was successfully performed without immediate complications following surgery. The patient had a normal voice and was tolerating a regular diet well. On postoperative day 3, the patient developed new hoarseness and dysphagia. An otolaryngologist was consulted, and flexible nasolaryngoscopy showed left vocal cord paralysis consistent with left RLNP. The patient was treated with a course of steroids, and her hoarseness and dysphagia had resolved at the 6-month follow-up visit. CONCLUSIONS: To our knowledge, this is the first report of delayed RLNP in patients undergoing anterior cervical discectomy and fusion. This rare complication should be discussed during preoperative patient counseling. Previous literature indicates the underlying pathophysiology for delayed onset of RLNP may be small vessel ischemia, vasospasm, or viral resurgence that leads to recurrent laryngeal nerve dysfunction.

Clinical Outcomes of Atlantoaxial Dislocation Combined with High-Riding Vertebral Artery Using C2 Translaminar Screws.

OBJECTIVE: Atlantoaxial stabilization procedures in high-riding vertebral artery (HRVA) cases are challenging. C2 translaminar screws are rigid and pose no risk to the vertebral artery. The aim of this study was to present clinical outcomes of atlantoaxial dislocation combined with HRVA using C2 translaminar screws. METHODS: Cases of atlantoaxial dislocation combined with HRVA surgically treated in our institution from 2007 to 2015 were retrospectively reviewed. Atlantodental interval and clivus-axial angle were measured. The Japanese Orthopaedic Association scale was used to evaluate neurologic status. RESULTS: There were 58 patients enrolled: 15 with instability and 43 with dislocation, 13 of which were irreducible. Incidence of bilateral HRVA was 5.2%. C1-C2 fixation was performed in 26 cases; atlantodental interval decreased from 9.9 ± 3.7 mm to 1.0 ± 1.7 mm (P < 0.05). C0-C2 fixation was performed in 32 cases; clivus-axial angle increased from 125° ± 13° to 150°± 15° (P < 0.05). Preoperative and postoperative Japanese Orthopaedic Association scores of 56 patients with myelopathy were 11.9 ± 2.8 and 14.6 ± 2.4, respectively (P < 0.05). Fusion rate was 93.1% (54/58) and at 4-month follow-up was 81% (47/58). In 14 cases of redislocation, final fusion was achieved; 3 of 14 required odontoidectomy. Four cases lacking bony fusion also required revision surgery. Redislocation rate was 31% (18/58), and reoperation rate was 12.1% (7/58). CONCLUSIONS: Surgical results of C2 translaminar screws are unsatisfactory, with high redislocation and reoperation rates in atlantoaxial dislocation cases. New treatment methods should be investigated to facilitate clinical outcomes. Extending fixed segments should be considered.

Posterior temporary C1-2 fixation for 3-part fractures of the axis (odontoid dens and Hangman fractures).

Case series study.To report the clinical outcomes of posterior temporary C1-2 fixation for 3-part fracture of the axis (Type II odontoid fracture according to Grauer classification combined with Hangman fracture).The 3-part fracture of the axis is rare and the treatment is controversy.A total of 8 patients with 3-part fracture of the axis were included in this study. X-rays, CT, and MRI prior to surgery were used to evaluate the cervical spine injury. Grauer classification, fracture angulation, and fracture translation were used to evaluate the fracture of dens. The neck disability index (NDI) and range of neck rotary motion were used to assess the neck function.The preoperative fracture angulation and fracture translation were 4.6 ±â€Š1.3° and 2.4 ±â€Š0.6 mm, respectively. The average operation time and blood loss were 109 ±â€Š27 minutes and 49 ±â€Š15 mL. No infection, vascular injuries or neural structure injuries was observed. All patients acquired bone healing at 5.9 ±â€Š2.0 months. The temporary instrumentation was removed at 10.8 ±â€Š1.3 months. The average NDI before and 2 days after removal of instrumentation were 10.1 ±â€Š4.0 and 7.1 ±â€Š3.0, respectively. At 1-year follow-up after instrumentation removal, the NDI was 1.8 ±â€Š0.7, which was much better than immediate NDI after instrumentation removal. The neck rotary motion (left rotation + right rotation) before and 2-day after instrumentation removal were 70.4 ±â€Š6.3° and 119.6 ±â€Š13.1°, respectively. At 1-year follow-up, the average neck rotary motion was 153.1 ±â€Š9.1°, which had significant different with rotary motion 2-day after the removal of temporary instrumentation.With regard to the high fracture fusion rates, low complications, and excellent predictable outcomes in patients treated with posterior temporary C1-2 pedicle screw fixation, the technique may be a suitable choice for 3-part fracture of the axis.

Low bone mineral density predicts the formation of new syndesmophytes in patients with axial spondyloarthritis.

BACKGROUND: This study aimed to investigate whether the presence of low bone mineral density (BMD) in patients with axial spondyloarthritis (axSpA) predicts formation of new syndesmophytes over 2 years. METHODS: One hundred and nineteen patients fulfilling the imaging arm of the Assessment of SpondyloArthritis International Society axSpA criteria were enrolled. All patients were under 50 years of age. The modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) was assessed by two trained readers blinded to the patients' data. BMD (lumbar spine, femoral neck or total hip) at baseline was assessed using dual-energy absorptiometry. Low BMD was defined as Z score ≤ - 2.0. Spinal radiographic progression was defined as worsening of the mSASSS by ≥ 2 points over 2 years. Logistic regression analyses were performed to identify predictors associated with development of new syndesmophytes and spinal radiographic progression. RESULTS: At baseline, 19 (16%) patients had low BMD. New syndesmophytes had developed in 22 (21%) patients at 2-year follow-up. New syndesmophyte formation after 2 years occurred more in patients with low BMD than in those with normal BMD (p = 0.047). In the multivariable analysis, current smoking, existing syndesmophytes and low BMD at baseline were associated with spinal radiographic progression (OR (95% CI) 3.0 (1.1, 7.7), 4.6 (1.8, 11.8) and 3.6 (1.2, 11.2), respectively). The presence of syndesmophytes at baseline and low BMD were predictors of new syndesmophytes over the following 2 years (OR (95% CI) 5.5 (2.0, 15.2) and 3.6 (1.1, 11.8), respectively). CONCLUSIONS: Low BMD and existing syndesmophytes at baseline were independently associated with the development of new syndesmophytes in young axSpA patients.

Anatomical variations of vertebral artery and C2 isthmus in atlanto-axial fusion: Consecutive surgical 100 cases.

VA anomalies in extra- and intraosseous regions of the craniovertebral junction (CVJ) is considered very carefully during the posterior screw fixation for the atlantoaxial instability (AAI). This study aims to compare the incidence and variations of VA anomalies, isthmus and pedicle size of C2 in 100 patients with AAI due to congenital skeletal anomaly (CSA) and acquired disease by using three-dimensional CT angiograms (3D CTA) before surgery. The CSA group contained 48 patients and the acquired disease group consisted of 52. In the CSA group, Os odontoideum was the major cause with 43 patients. The causes of acquired disease were RA in 16 patients and OA in 36 patients. Five patients had the anomalous VA in only CSA group; fenestration 2 patients and persistent first intersegmental (PFIS) artery 3 patients. Between CSA and acquired disease groups, no significant differences were found in the isthmus height, internal height, and pedicle width of C2 except the right internal height that is bigger in CSA group. The high-riding VA (isthmus height <4 mm or internal height <2 mm) had no significant difference between CSA group (27.1%) and acquired disease group (34.6%). However, in acquired disease group, patients with rheumatoid arthritis had smaller left internal height (4.21 ±â€¯1.63 vs. 5.51 ±â€¯1.83 mm) and pedicle width (4.11 ±â€¯1.05 vs. 5.05 ±â€¯1.66 mm) of C2 than those of patients with degenerative osteoarthritis. Therefore, in the case of atlantoaxial fusion, we should contemplate VA anomaly and the high-riding VA, especially in patients with CSA and RA.

Nonoperative management of C-2 dens fractures: Single center experience and review of the literature.

OBJECTIVE: The demographic change in the population leads to a rising number of patients presenting with fractures of the cervical spine, especially C-2, due to falls. With an increase of co-morbidities in these elder patients, the risk for intra- and postoperative complications is increased likewise. Thus, an alternative strategy instead of operative management of these fractures should be taken into account whenever possible. Conservative management of dens fractures in the elderly is still a subject of great controversy despite numerous studies on this topic. The aim of this study was to analyze the rate of successful osseous consolidation of C-2 fractures with conservative treatment by wearing a semi-rigid collar or halo thoracic vest without further surgical intervention. PATIENTS AND METHODS: We analyzed the medical records and CT-scan of the cervical spine of 254 patients with C-2 fractures retrospectively, who were admitted to our department between January 1990 and September 2015. Fractures were diagnosed by CT-scan of the cervical spine and classified according to the Anderson - D`Alonzo classification. 183 patients were submitted to surgery as treatment of choice. In 71 patients a conservative management with external immobilization was chosen. The latter group was subjected to study analysis. RESULTS: 71 patients (mean age 74.08 years ±â€¯16.06 years) were diagnosed with C-2 fractures (Typ I: 4; Typ II 36; Typ III: 31) and treated conservatively using a Philadelphia collar (n = 57), or a halo-thoracic vest (n = 14), respectively. 12 patients were lost to follow up and excluded from further analysis. Conservative treatment of the fractures was deemed successful when a bony consolidation of the fracture in follow-up CT scans was seen (45 of 59 patients; 76.3%). 20 patients with a Type II fracture (20/28, 71.4%) showed a successful ossification. In 14 patients (overall 23.7%; Typ I: 1 (7.14%), Typ II: 8 (57.14%), Typ III: 5 (35.71%)) external immobilization failed to achieve primary stability. These patients were submitted to consecutive surgery. CONCLUSION: From our data it can be concluded that elderly patients, presenting with non-dislocated Type II fractures of the axis without accompaining neurological deficits, will have a more than 70% chance for a bony consolidation by conservative management. Consolidation rates may be estimated even higher in Type I and III fractures. Therefore, we suggest that external immobilization might be a valuable option to treat elderly patients with these fractures under certain circumstances.

C2 Translaminar Screw Fixation in Children.

BACKGROUND: Axis (C2) screw fixation has been shown to be effective in treating disorders that necessitate cervical stabilization. Although translaminar C2 screws have demonstrated clinical efficacy in adults, this technique has not yet been thoroughly investigated in children. This study describes the indications, technique, and results of translaminar C2 screw fixation in a case series of pediatric cervical spine disorders. METHODS: We searched the orthopaedic database at our institution for patients who had undergone a cervical spinal fusion that encompassed C2 between 2007 and 2017. Operative records were reviewed to determine if C2 screw fixation was performed and, if so, the type of C2 screw fixation. Clinical data with regard to patient age at surgery, diagnosis, procedure details, intraoperative complications, and postoperative complications were recorded. Preoperative and postoperative computer tomographic scans were reviewed to determine laminar measurements and containment, respectively. RESULTS: In total, 39 C2 translaminar screws were placed in 23 patients that met our inclusion criteria. The mean age was 12.6 years (range, 5.2 to 17.8 y) with a mean of 2 levels fused (range, 1 to 6). Diagnoses included 7 patients with instability related to skeletal dysplasia, 6 os odontoideum, 4 congenital deformities, 3 basilar invaginations, 2 cervical spine tumors, and 1 fracture. Indications for C2 translaminar screws included 14 cases with distorted anatomy favoring C2 translaminar screws, 6 cases without explicit reasoning for translaminar screw usage in the patient records, and 3 cases with intraoperative vertebral artery injury (1 sacrificed secondary to tumor load and 2 others injured during exposure because of anomalous anatomy). The vertebral artery injuries were not due to placement of any instrumentation. There were no screw-related intraoperative or postoperative complications and no neurological injuries. All patients demonstrated clinical union or healing on follow-up with no episodes of nonunion. CONCLUSIONS: Translaminar C2 screw fixation can be reliably used in the pediatric population. Our series contained no screw-related complications, no neurological injuries, and all patients demonstrated clinical union or healing. LEVEL OF EVIDENCE: Level IV-Case series.

Extraspinal-Interdural Surgical Approach for C2 Neurinomas-Report of an Experience with 50 Cases.

OBJECTIVE: We report our experience with surgery in 50 patients with C2 neurinomas. The anatomic subtleties of these discrete forms of tumors and their surgical implications are analyzed. METHODS: During the period 2006-2016, we operated on 50 patients with 55 C2 neurinomas. Type A tumors were located within the spinal canal, type B tumors were located in the lateral gutter, and type C tumors had a paraspinal extension. By working within the dural confines of the tumor and appropriately angulating the microscope, the entire tumor bulk extending into 1 or all 3 compartments was resected. Follow-up duration ranged from 3 months to 10 years (mean 68 months). RESULTS: This series included 36 male and 14 female patients. Age range of patients was 14-70 years (mean age 36 years). Progressive symptoms of myelopathy were present in 41 patients. There were 16 type A + B tumors, 27 type B tumors, 10 type B + C tumors, and 2 type A + B + C tumors. All patients experienced symptom improvement after surgery and were able to resume their normal lifestyle. CONCLUSIONS: C2 neurinomas arise in the region of the C2 ganglion, and despite the fact that some achieve a large size, they remain confined within the dura. Radical tumor resection can be achieved by working within the layers of the dural cover. Bone removal and opening of spinal dura for tumor exposure and resection can be avoided.