C2 Synchondrosal Injuries: A Case Report and Anatomic Review.

Developmental succession in the pediatric patient requires special consideration in post-traumatic assessment. An understanding of the sequential development of this region and common patterns of injury can provide an accurate initial assessment before proceeding to further management and prognostic evaluation. Primarily, this article focuses on the synchondrosal development of C2 and its role in the craniocervical junction, as well as its common patterns of injury. This article presents two sample cases and offers a review of treatment options with added prognostic factors.

Can Anterior Osteophyte Fractures Be Distinguished From Fracture Mimics in the Subaxial Cervical Spine? A Retrospective Analysis Evaluating Reported Fractures With Clinical Management Correlation.

OBJECTIVE: This study aimed to retrospectively distinguish true- from false-positive fractures of anterior subaxial cervical osteophytes, which were reported on noncontrast computed tomography reports, and to correlate the imaging findings with patient symptoms and analyze the downstream impact on management of both true and false positive fractures. METHODS: A total of 127 patients had computed tomography reports of anterior osteophyte fractures. Radiology reports and imaging studies were evaluated to distinguish true fractures from fracture mimics. We analyzed imaging features including rigid spine (RS), prevertebral soft tissue swelling (PVSTS), and instability. We categorized symptoms and examination findings into 3 groups (0, asymptomatic; 1, neck pain; 2, neurological symptoms). Management was categorized into 3 groups (0, no treatment; 1, external bracing; 2, surgery). Associations between imaging features, fracture classification, clinical symptoms, magnetic resonance imaging utilization, and management were calculated using χ2 with Cramer V test to determine effect size. RESULTS: Eighty patients had false-positive fractures, and 47 were true positive. There were significant associations between magnetic resonance imaging utilization and fracture classification (P ≤ 0.001), PVSTS (P ≤ 0.005), patient symptoms (P ≤ 0.001), and patient management (P ≤ 0.001). There were significant associations between patient management and fracture classification (P ≤ 0.001), patient symptoms (P ≤ 0.001), PVSTS (P ≤ 0.001), imaging findings of instability (P ≤ 0.001), and RS (P ≤ 0.021). There were significant associations between fracture classification and patient symptoms (P ≤ 0.045), and RS (P ≤ 0.006). CONCLUSIONS: Subaxial isolated anterior osteophyte fractures fell into 3 major categories. By our methodology, if a suspected fracture was determined to be a fracture mimic in an asymptomatic patient, it was unlikely to be clinically significant. Isolated anterior osteophyte fractures without neurological symptoms or more concerning imaging findings can be treated conservatively. Finally, fractures that demonstrate indirect signs of instability or are associated with RS are more associated with surgical management.

Cervical MRI assessment of traumatic anterior atlanto-occipital membrane complex injuries with evaluation of ancillary findings.

BACKGROUND AND PURPOSE: The purpose of this study was to identify and classify the different types of anterior atlanto-occipital membrane complex injuries on MRI and evaluate for the presence, size, and location of a prevertebral effusion on the preceding CT exams. MATERIALS AND METHODS: Patients who suffered an anterior atlanto-occipital membrane complex injury were identified retrospectively utilizing Nuance mPower software. An anatomic-based description of the location of the anterior atlanto-occipital membrane complex injury was recorded along with any additional osteoligamentous trauma of the craniocervical junction. The preceding cervical CT exams for these patients were reviewed for the presence and location of a prevertebral effusion. RESULTS: Fifty patients were identified with an acute, post-traumatic anterior atlanto-occipital membrane complex injury. Three distinct patterns of anterior atlanto-occipital membrane complex injury were observed. Nineteen patients demonstrated increased STIR signal with disruption of the anterior atlanto-occipital membrane, ten patients demonstrated increased STIR signal with disruption of the anterior atlanto-axial membrane, and twenty-one patients demonstrated increased STIR signal with disruption of both the anterior atlanto-occipital membrane and anterior atlanto-axial membrane. An effusion at the C1-C2 level was present in greater than 90% of patients with anterior atlanto-occipital membrane complex injury. CONCLUSIONS: The presence of a craniocervical prevertebral effusion on CT in trauma patients may raise suspicion for an injury to the anterior atlanto-occipital membrane complex and potentially trigger additional investigation with cervical MRI.

Long-term outcomes of fractionated proton beam therapy for benign or radiographic intracranial meningioma.

PURPOSE: Benign intracranial meningioma is one of the most common primary brain neoplasms. Proton therapy has been increasingly utilized for nonoperative management of this neoplasm, yet few long-term outcomes studies exist. METHODS: The medical records of a total of 59 patients with 64 lesions were reviewed under a prospective outcomes tracking protocol for histologically proven or radiographically benign meningioma. The patients were treated with proton therapy at the University of Florida Proton Therapy Institute between 2007 and 2019 and given a median dose of 50.4 GyRBE at 1.8 GyRBE (relative biological effectiveness) (range 48.6-61.2 GyRBE) in once-daily treatments. RESULTS: With a median clinical and imaging follow-up of 6.3 and 4.7 years, the rates of 5-year actuarial local progression and cumulative incidence of grade 3 or greater toxicity were 6% (95% confidence interval [CI] 1%-14%), and 2% (95% CI < 1%-15%), respectively. Two patients experienced local progression after 5 years. The 5-year actuarial overall survival rate was 87% (95% CI 74-94%). CONCLUSION: Fractionated PBT up to 50.4 GyRBE is a safe and highly effective therapy for treating benign intracranial meningioma.

Incisional Wound Vacuum-Evaluation of Wound Outcomes in Comparison With Standard Dressings for Posterior Spinal Fusions in Traumatic Patients.

BACKGROUND: Postoperative incisional negative pressure wound vacuum-assisted closure (VAC) dressings are being used as a primary dressing to optimize wound healing and help avoid complications of infection and dehiscence. Few studies have investigated whether application of VAC dressings on postoperative posterior spinal wounds can reduce the incidence of surgical site infections. OBJECTIVE: To describe our single-surgeon experience of using primary VAC after posterior spinal fusion (PSF) in a large sample of trauma patients. METHODS: This was an Institutional Review Board-approved retrospective comparative study and included all trauma patients presenting to our level 1 safety-net trauma center who required PSF and were operated on by the senior surgeon between 2016 and 2021. Primary outcomes were complications (surgical site infection, readmission for infection, and wound-related return to operating room [OR]) within 90 days after surgery. χ2 testing and Student t testing were used to assess differences between treatment groups while bivariate and multivariate regression was performed for outcome assessment. RESULTS: Two hundred sixty-four patients met criteria and were included. One hundred fifty-seven (59%) were treated with standard dressing and 107 (41%) with VAC. Patients treated with VAC were more likely to be older (P = .015), have diabetes (P = .041), have an elevated body mass index (P = .020), and had more levels of fusion (P = .002). Despite this, presence of VAC was independently associated with decreased 90-day infection (hazard ratio = 0.397, P = .023) and decreased 90-day return to OR for wound-related reasons (hazard ratio = 0.099, P = .031). CONCLUSION: Compared with the use of standard dressing, VAC was found to decrease surgical site infection and return to OR risk in trauma patients undergoing PSF.

Is Contrast-Enhanced Computed Tomography Redundant for Suspected Intracranial Infection in the Emergency Setting?

OBJECTIVE: There are currently no guidelines for when to use intravenous contrast with head computed tomography (CT) when there is suspected acute intracranial infection. The purpose of our study was to determine the proportion of cases with enhancing findings on CT that also have conspicuous correlating associated findings on noncontrast CT, which would have on their own merited further evaluation with magnetic resonance imaging, the criterion standard for evaluating central nervous system pathology. METHODS: A retrospective keyword search of the history and clinical information fields in radiology reports for CT examinations of the head without and with contrast from the period January 1, 2004, to October 31, 2021 was performed. Patients with prior head surgery or a history of cancer were excluded. For remaining patients, the noncontrast CT was reviewed for vasogenic edema or mass effect as markers of a possible acute infection, and the presence of background hypodense white matter changes was noted and graded as either absent, mild/scattered, or confluent. Subsequently, the companion contrast-enhanced CT was reviewed for an enhancing abnormality. Chart review was performed to confirm that an infectious process was the ultimate clinical diagnosis in patients with enhancing abnormalities. RESULTS: Of 343 patients meeting study inclusion/exclusion criteria, 39 had acute infections with an enhancing abnormality on CT (prevalence 11.3%). Thirty-two of these 39 patients also had correlative findings on the noncontrast CT. Noncontrast CT had a positive predictive value of 100%, negative predictive value of 97.7%, sensitivity of 82.1%, specificity of 100%, and accuracy of 98.0% for detecting markers (vasogenic edema and/or mass effect) associated with an enhancing abnormality. Vasogenic edema was the most common noncontrast CT finding in patients who had an infectious enhancing lesion (32 of 39), followed by mass effect (22 of 39). The 7 cases where the acute infection was occult on noncontrast CT were due to leptomeningitis (n = 3), confluent background white matter changes masking the vasogenic edema surrounding intra-axial lesions (n = 3), and a small 0.5 cm extra-axial abscess. CONCLUSIONS: Most acute intracranial infections with an enhancing CT finding also have a correlative conspicuous noncontrast finding that on its own would merit further evaluation with magnetic resonance imaging, the criterion standard for investigating central nervous system disease, and therefore, in the setting of suspected intracranial infection, contrast-enhanced CT is redundant in most cases. Contrast-enhanced CT primarily provides diagnostic benefit in patients with confluent background white matter changes that may mask vasogenic edema on noncontrast CT.

Utility of Anterior Atlantodens Interval Widening on Cervical Spine CT for Assessing Transverse Atlantal Ligament Injury.

STUDY DESIGN: Retrospective, cross-sectional. OBJECTIVES: To identify trauma patients with confirmed tears of the transverse atlantal ligament on cervical MRI and measure several parameters of atlanto-axial alignment on cervical CT, including the anterior atlantodens interval, to determine which method is most sensitive in predicting transverse atlantal ligament injury. METHODS: Adult trauma patients who suffered a transverse atlantal ligament tear on cervical MRI were identified retrospectively. The cervical CT and MRI exams for these patients were reviewed for the following: anterior and lateral atlantodens interval widening, lateral C1 mass offset, C1-C2 rotatory subluxation, and transverse atlantal ligament injuries on cervical MRI. RESULTS: Twenty-six patients were identified with a tear of the transverse atlantal ligament on cervical MRI. Twelve percent of these patients demonstrated an anterior dens interval measuring greater than 2 mm, 26% of patients demonstrated lateral mass offset of C1 on C2 (average offset of 2.4 mm), 18% of patients demonstrated an asymmetry greater than 1 mm between the left and right lateral atlantodens interval, and one patient demonstrated atlanto-axial rotation measuring greater than 20%. Ten patients had an accompanying C1 burst fracture and eight patients had a C2 fracture. One patient demonstrated widening of the atlanto-occipital joint space greater than 2 mm indicative of craniocervical dissociation injury. CONCLUSIONS: An anterior atlantodens interval measuring greater than 2 mm is an unreliable methodology to screen trauma patients for transverse altantal ligament injuries and atlanto-axial instability. Moreover, C1 lateral mass offset, lateral atlantodens asymmetry, and atlanto-axial rotation were all poor predictors of transverse atlantal ligament tears.

Imaging Review of the Endoscopic Operative Corridor for Clivus Lesions.

Traditional transcranial approaches for lesions involving the clivus, in particular skull base chordoma have several disadvantages for midline skull base lesions as compared to the endoscopic endonasal approach (EEA), such as higher morbidity and lesser extent of resection. These disadvantages led to the development of endoscopic skull-base approaches to access pathology that involves the anterior cranial fossa, central skull base, and lower skull base lesions. In particular, lesions of the clivus are well suited for EEA. Surgical access of the clivus falls into 2 stages: the endonasal approach for access, and the endonasal resection of tumor. The objective of this article is to review the anatomy along the operative corridor for the purpose of image interpretation in preoperative planning in the context of EEA. We provide an imaging review of the sinonasal anatomy used for access by otolaryngologists and the anatomy of the clivus used by neurosurgeons for preoperative planning and resection.

Interrelationship Between Craniocervical Dissociation Spectrum Injuries and Atlantoaxial Instability on Trauma Cervical MRI Examinations.

Background and purpose Craniocervical dissociation injuries encompass a spectrum of osteoligamentous injuries between the skull base and C1-C2 that may be treated via prolonged external immobilization versus occipital cervical fusion depending on the risk of persistent craniocervical instability. However, the presence of atlantoaxial instability (AAI) at C1-C2, as determined by transverse atlantal ligament (TAL) integrity with or without a C1 fracture, may guide the neurosurgical management of craniocervical dissociation spectrum injuries (CDSI) since it implies an overall greater degree of instability at the craniocervical junction (CCJ). Materials and methods Adult trauma patients who suffered a transverse atlantal ligament injury on cervical magnetic resonance imaging (MRI) were identified retrospectively. The cervical computed tomography (CT) and magnetic resonance imaging examinations for these patients were reviewed for additional traumatic findings. Demographic information, treatment, and outcome information were recorded. Results Twenty-nine trauma patients presented to the emergency department (ED) with an acute, midsubstance transverse atlantal ligament tear on cervical magnetic resonance imaging. Thirty-one percent of patients demonstrated a tear in at least one major craniocervical ligament (atlanto-occipital capsular ligaments, alar ligaments, and tectorial membrane {TM}) with 14% demonstrating a tear in two major craniocervical ligaments and no patients demonstrating a tear in all three major craniocervical ligaments. Minor craniocervical ligament injuries (anterior atlanto-occipital membrane complex {AAOMc} and posterior atlanto-occipital membrane complex {PAOMc}) were common and observed in 76% of patients. Conclusions Our study suggests that multiple major craniocervical junction ligamentous injuries on cervical magnetic resonance imaging are relatively uncommon in the setting of transverse atlantal ligament injury.

Appropriateness of Cervical Magnetic Resonance Imaging in the Evaluation and Management of C1 Jefferson Fractures.

BACKGROUND: Traditionally, C1 fractures have been designated as stable or unstable based on the inherent integrity of the transverse altantal ligament. The purpose of our study was to identify adult trauma patients with C1 fractures on cervical computed tomography and evaluate whether C1-C2 alignment differed in patients with and without an associated transverse atlantal ligament injury on follow-up cervical magnetic resonance imaging. METHODS: Adult trauma patients who suffered a C1 fracture were identified retrospectively. The cervical computed tomography examinations for these patients were reviewed for the following: C1 fracture classification, anterior atlantodens interval (ADI) widening, asymmetry in the lateral atlantodens interval, C1 lateral mass offset, and atlantoaxial rotation. RESULTS: Acute C1 fractures were grouped into those with an unequivocal transverse atlantal ligament injury (n = 12), and patients with an unequivocally intact transverse atlantal ligament (n = 20). Three patients were classified as indeterminate for transverse atlantal ligament injury. Statistically significant increases in lateral ADI asymmetry and combined C1 lateral mass offset were identified in patients with transverse atlantal ligament tears. CONCLUSIONS: Lateral ADI asymmetry (using a cutoff of >3 mm), combined C1 lateral mass offset, and anterior ADI demonstrate robust specificity to "rule in" transverse atlantal ligament injury. Atlantoaxial alignment was overall relatively insensitive as a screening test although sensitivity can be improved using a cutoff of >2 mm for lateral ADI asymmetry. Our findings reinforce the role of cervical magnetic resonance imaging in the diagnostic workup and clinical management of trauma patients with an acute burst fracture of the C1 vertebra.

Meningiomas Can Present as Intracranial Hemorrhage in Rare Cases: A Case Report of a Patient With a History of Minor Trauma and Massive Intracranial Hemorrhage.

Meningiomas are relatively common intracranial tumors. While typically discovered incidentally or related to symptoms from regional mass effect, on rare occasions, they can present as acute intracranial hemorrhage. We report a case of a 62-year-old male who presented with significant acute intracranial hemorrhage with a history of minor trauma. Imaging workup demonstrated a hemorrhagic mass to be the likely cause of the hemorrhage. Upon resection of the mass, pathology demonstrated meningioma. It is important to thoroughly investigate intracranial hemorrhage, particularly when it appears out of proportion to any known causative event, in order to accurately diagnose, manage, and treat these patients.

Disease Control after Radiotherapy for Adult Craniopharyngioma: Clinical Outcomes from a Large Single-Institution Series.

PURPOSE: To report disease control and treatment-related side effects among adult patients with craniopharyngioma treated with radiotherapy. METHODS: We performed a single-institution review of adult patients (> 21 years old) with craniopharyngioma treated with radiotherapy either definitively or postoperatively for gross residual disease. We report disease control, survival, and radiotherapy-related side effects. RESULTS: A total of 49 adult patients with craniopharyngioma were included, 27 of whom were treated at initial presentation and 22 for recurrent disease following initial surgery and observation. Overall, 77% received radiotherapy postoperatively (either after primary surgery or surgery for recurrence). With a median clinical and radiographic follow-up of 4.2 (range, 0.4-21.6) years and 3.0 (range, 0-21.5) years, the 5- and 10-year local control rates were 100 and 94%, respectively. The 5- and 10-year overall survival rates were 80 and 66%, respectively. Eleven percent of patients experienced grade 2 vision deterioration and 18% suffered grade 2 endocrinopathies following radiotherapy. CONCLUSIONS: Radiotherapy provides excellent disease control with acceptable toxicity among adult patients with craniopharyngioma. These data support the use of fractionated radiotherapy in adult patients with recurrent or gross residual disease after surgery. For inoperable patients or those with moderate or high surgical risk to neurologic and/or vascular structures, we advocate for limited surgical resection and postoperative radiotherapy to balance optimal tumor control with tumor- and treatment-related morbidity.

Current Advances in the Management of Adult Craniopharyngiomas.

Craniopharyngiomas (CPs) are slow growing, histologically benign intracranial tumors located in the sellar-suprasellar region. Although known to have low mortality, their location and relationship to the adjacent neural structures results in patients having significant neurologic, endocrine, and visual comorbidities. The invasive nature of this tumor makes complete resection a challenge and contributes to its recurrence. Additionally, these tumors are bimodally distributed, being treated with surgery, and are followed by other adjuncts, such as focused radiation therapy, e.g., Gamma knife. Advances in surgical techniques, imaging tools, and instrumentations have resulted in the evolution of surgery using endoscopic techniques, with residual components being treated by radiotherapy to target the residual tumor. Advances in molecular biology have elucidated the main pathways involved in tumor development and recurrence, but presently, no other treatments are offered to patients, besides surgery, radiation, and endocrine management, as the disease and tumor evolve. We review the contemporary management of these tumors, from the evolution of surgical treatments, utilizing standard open microscopic approaches to the more recent endoscopic surgery, and discuss the current recommendations for care of these patients. We discuss the developments in radiation therapy, such as radiosurgery, being used as treatment strategies for craniopharyngioma, highlighting their beneficial effects on tumor resections while decreasing the rates of adverse outcomes. We also outline the recent chemotherapy modalities, which help control tumor growth, and the immune landscape on craniopharyngiomas that allow the development of novel immunotherapies.

Occult craniocervical dissociation on cervical CT: an under-appreciated presentation of craniocervical trauma requiring occipital cervical fusion.

BACKGROUND AND PURPOSE: Craniocervical dissociation is a rare and life-threatening injury that results from a significant hyperflexion-hyperextension force. Occult craniocervical dissociation is defined as an unstable craniocervical injury in the absence of atlanto-occipital joint space widening or other skull base line abnormality. The early and accurate diagnosis of craniocervical dissociation is crucial since the early diagnosis and subsequent stabilization with occipital-cervical fusion has been shown to reduce neurologic morbidity and mortality. Several normative skull base lines have been developed to predict craniocervical dissociation. The purpose of our study was to measure the atlanto-occipital joint space and four other common skull base lines in patients who underwent occipital-cervical fusion for post-traumatic craniocervical instability. MATERIALS AND METHODS: Patients who underwent occipital-cervical fusion for craniocervical injury were identified retrospectively using a keyword search of radiology reports using Nuance mPower software. The cervical CT and MRI exams for these patients were reviewed and the atlanto-occipital joint space, Powers ratio, Wackenheim line, posterior axial line, and basion dens interval were measured. Detailed descriptions of craniocervical ligament injuries on MRI were recorded along with patient demographic information, clinical history, management, and outcome. RESULTS: Nine adult patients who underwent occipital-cervical fusion for an acute craniocervical injury were identified. Six patients demonstrated an atlanto-occipital joint space measuring 2 mm or less on cervical spine CT with no additional abnormality in the Powers ratio, Wackenheim line, posterior axial line, or basion-dens interval. Three patients demonstrated widening of the atlanto-occipital joint space with two patients demonstrating an abnormality in at least two additional skull base lines. Clinical outcomes were variable with nearly half of the patients demonstrating persistent neurologic deficits, including one quadriplegic patient. CONCLUSIONS: A normal atlanto-occipital joint space and skull base line measurements on cervical CT demonstrated a low predictive value for detecting unstable craniocervical injuries. Occult craniocervical dissociation was present in two-thirds of patients who underwent occipital cervical fusion for acute, craniocervical trauma. A high clinical and radiologic index of suspicion for craniocervical trauma with subsequent follow-up cervical MRI to directly evaluate ligamentous integrity is necessary to accurately diagnose and triage patients with high velocity trauma.

Imaging of dental infections.

Dental infections are a common presentation in the emergency department (ED). To help guide clinical management for these infections, the radiologist must be familiar with the anatomy of the oral cavity and neighboring structures, the range of appearance of dental infections, and the routes along which they may spread. Computed tomography (CT) is often performed when severe dental infections are suspected. This pictorial essay reviews the anatomy pertinent to the imaging evaluation of dental infections and depicts a spectrum of pathology that may be encountered, ranging from simple dentoalveolar infections to complex multispatial infections.

Radiologic utility of the Gehweiler and AO spine classification systems for C1 Trauma: A retrospective review from a Level I trauma center.

Objective: The purpose of our study was to identify adult trauma patients with an acute C1 burst fracture, evaluate for concomitant transverse atlantal ligament (TAL) injury, and apply the modified Gehweiler and AO spine classification systems to determine the utility of these classification systems in accurately defining C1 trauma. Materials and Methods: Adult trauma patients with an acute C1 fracture were identified retrospectively using Nuance mPower software. The C1 fracture was described based on whether the fracture involved the anterior arch, posterior arch, lateral mass, medial tubercle, and/or transverse process. If follow-up cervical magnetic resonance imaging (MRI) was performed, the presence and location of an associated TAL injury was recorded. The anatomic location of the C1 burst fracture and TAL injury, if present, were compared with the descriptive classification systems outlined by Gehweiler/Dickman (modified) and the AO Spine society. Any additional osseous trauma of the skull base and C1-C2 was also recorded along with relevant clinical history and management. Results: Thirty-nine patients were identified with an acute C1 burst fracture on cervical computed tomography (CT) with seventy-seven percent of patients undergoing follow-up cervical MRI. Observed fracture patterns were divided into five distinct types based on CT findings and further subdivided based on the integrity of the transverse altantal ligament on MRI. TAL tears were observed exclusively in type 3 fractures (anterior and posterior arch fractures) and type 4 fractures (anterior arch, posterior arch, and lateral mass fractures). The modified Gehweiler classification system failed to accurately describe the anatomic location of the C1 fracture in forty-four percent of patients, whereas the AO spine was too broad and failed to accurately describe fracture location in our cohort. Conclusions: The Gehweiler and AO spine classifications demonstrated significant shortcomings in the accurate description of patients with C1 trauma. Whereas the Gehweiler system did not accurately describe the anatomic location of the various C1 fractures, the AO spine system was too broad and failed to radiologically classify fracture location. Moreover, there was a high number of patients with AO spine type B injuries without atlantoaxial translation that nevertheless required C1-C2 fusion for atlantoaxial instability. We suggest the need for an updated classification system that takes into account both the CT (fracture location) and MRI (TAL integrity) appearance of C1 trauma. An updated classification strategy will offer a radiologic standardization of C1 trauma that will aid in future research studies and help optimize patient management.

A Rare Case of Life-Threatening Multicompartmental Spontaneous Intracranial Hemorrhage From a Grade 1 Convexity Meningioma.

Meningiomas are slowly growing benign tumors. The incidence of hemorrhage associated with intracranial meningiomas is in the 0.5%-2.4% range. However, intracranial meningiomas with hemorrhagic presentation are associated with higher rates of overall major morbidity (36%) and mortality (21.1%). We report a case of a convexity meningioma presenting with intraparenchymal hematoma and bilateral acute subdural hematomas (SDH) in a comatose patient (Glasgow Coma Scale (GCS) score: 7) who had a history of recurrent episodes of headaches over the past few months. Hemorrhagic presentation of a meningioma is a rare but potentially devastating event. Early recognition of the potential underlying meningioma as a cause of bleeding followed by rapid appropriate additional imaging is crucial to direct treatment plans to achieve the best outcome.

C1-C2 Dorsal Epidural Hematoma on Cervical Spine CT: A Novel Imaging Sign of Posterior Atlanto-Occipital Membrane Stripping Injury.

BACKGROUND AND PURPOSE:  Identify patients with a dorsal epidural hematoma at C1-C2 and examine the major craniocervical junction ligaments for injury on follow-up magnetic resonance imaging. MATERIALS AND METHODS:  Adult and pediatric trauma patients who suffered a dorsal epidural hematoma at C1-C2 were identified using Nuance mPower software (Nuance Communications, United States). The cervical computed tomography and magnetic resonance imaging exams for these patients were reviewed for craniocervical junction osteoligamentous injuries. An age-matched control group was obtained. RESULTS:  Eight trauma patients were identified with a dorsal epidural fluid collection at C1-C2. All patients with a dorsal epidural hematoma, who underwent follow-up cervical magnetic resonance imaging demonstrated a stripping injury of the posterior atlanto-occipital membrane from the C1 posterior arch with increased short tau inversion recovery signal in the posterior atlanto-occipital membrane complex. Disruption of additional major craniocervcial ligaments on magnetic resonance imaging was relatively common with the most frequently associated ligamentous injuries involving the tectorial membrane (five patients) followed by the alar ligaments and anterior altanto-occiptial membrane (four patients each).  Conclusions: A C1-C2 dorsal epidural hematoma is a rare injury that may be identified on cervical spine computed tomography but may be easily overlooked by the radiologist. We propose that a C1-C2 dorsal epidural hematoma is a direct result of a significant hyperflexion-hyperextension force with subsequent stripping of the posterior atlanto-occipital membrane from the posterior C1 arch. Trauma patients with a C1-C2 dorsal epidural hematoma on cervical spine computed tomography should undergo a cervical magnetic resonance imaging examination to evaluate the integrity of the posterior atlanto-occipital membrane complex and remaining craniocervical junction ligaments for injury.

Midbrain Ischemic Strokes Presenting as Isolated Internuclear Opthalmoplegia.

Stroke can present with unique neurologic symptoms, which can be used to help determine the location of the stroke. Internuclear ophthalmoparesis (INO), also known as internuclearophthalmoplegia, is a distinct gaze abnormality with impaired horizontal eye movements with compromised adduction of the affected eye, and abduction nystagmus of the contralateral eye. Infarcts involving the medial longitudinal fasciculus in either the pons or midbrain can result in INO. We present two cases of midbrain ischemic stroke, which presented as isolated INO. The midbrain has a unique and intricate vascular supply including branches from the basilar, superior cerebellar, posterior cerebral, posterior communicating, anterior choroidal, and posterior choroidal arteries, which is reviewed. Infarcts involving the paramedian midbrain, which is supplied by short circumferential arteries and penetrating branches arising from the posterior cerebral artery and superior cerebellar artery, can result in INO.

Bilateral Hypertrophic Olivary Degeneration Following Brainstem Insult: A Retrospective Review and Examination of Causative Pathology.

Hypertrophic olivary degeneration is a rare condition caused by a lesion in the Guillain-Mollaret triangle which leads to trans-synaptic degeneration resulting in the degenerative hypertrophy of the inferior olivary nucleus. This condition presents clinically with palatal tremor but can also produce ocular myoclonus or cerebellar signs. While any lesion that occurs within the Guillian-Mollaret triangle and results in the deafferentation of the inferior olive can lead to hypertrophic olivary degeneration, the most common etiologies include ischemic and hemorrhagic stroke, vascular malformation, neoplasm, and iatrogenic injury related to surgery. We report a series of 7 patients who presented with this condition bilaterally on MRI imaging, including 1 case which represents the first report of toxoplasmosis leading to the development of bilateral hypertrophic olivary degeneration and only the third reported case, unilateral or bilateral, related to an infectious etiology.