Retropharyngeal pseudomeningocele after atlanto-occipital dislocation: report of two cases

Posttraumatic Retropharyngeal Pseudomeningocele—A Case Report

A retropharyngeal pseudomeningocele after cervical vertebral fracture dislocation is an extremely rare complication and often associated with hydrocephalus. It usually presents with respiratory difficulty and dysphagia, sometimes as an incidental finding in radiological study. We reported a case of 45-year-old female patient who had posttraumatic lower cervical prevertebral retropharyngeal pseudomeningocele, found as an incidental finding in a routine radiological workup. Patient underwent ACDF but expired 2 weeks postoperatively due to respiratory failure. Although the prognosis of retropharyngeal pseudomeningocele depends upon the severity of initial trauma, early recognition and management can prevent enlargement of cyst and development of respiratory difficulty and dysphagia.

Surgical management of a retropharyngeal pseudomeningocele: Case report

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Retropharyngeal pseudomeningocele is a rare condition, which is usually detected weeks after trauma.

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Early recognition and accurate diagnosis might help avoiding management delay and late intervention.

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As surgical management is considered to be the definitive management, multidisciplinary management involving a team of Otolaryngology and Neurosurgery skull base surgeons is essential to achieve optimal outcomes.

Introduction

Retropharyngeal pseudomeningocele is a very rare form of pseudomeningocele, that is known to be associated with cervical trauma. Identifying such pathology can be challenging leading to delayed management.

Case presentation

We report a case of post-traumatic retropharyngeal pseudomeningocele that was managed surgically in a 21-year-old gentleman with poly-trauma injuries due to a motor vehicle accident. After 10 weeks since the traumatic event, magnetic resonance imaging (MRI) and computerised tomography (CT) scan showed evidence of bilateral atlanto-occipital dislocation and a fluid collection of 8 × 4 × 2 cm in the retropharyngeal space. The patient was found to have dysphagia and muffled voice with difficult visualisation of the vocal cords upon examination. After a multidisciplinary team decision, the patient underwent cerebrospinal fluid (CSF) leak management, pseudomeningocele resection and dural defect repair with shunting conducted by the Neurosurgery and Otolaryngology. Postoperative assessments and patient's symptoms, at 9 months follow-up, were satisfactory and reassuring.

Discussion

It’s believed that conservative management with bed rest, elevation of bed head and acetazolamide is the initial step in management. As an alternative measure, shunting of the CSF had led to resolution of the collection. However, surgical removal of the collection and direct dural defect repair have been suggested in the literature but needed to be properly studied.

Conclusion

Early recognition of this condition is important to avoid management delay. With a multidisciplinary approach, surgical management can be safe and an acceptable option for retropharyngeal pseudomeningocele.

Delayed Post Caudal Catheter Placement Pseudomeningocele: A Case Report

We present a rare case of a 7-month-old infant who developed a pseudomeningocele 16 days after an uneventful caudal catheter placement. The patient did not exhibit neurological deficits or signs of infection, and the mass increased in size with Valsalva maneuver. Pseudomeningocele, an abnormal collection of cerebrospinal fluid around an opening in the dura mater, can be iatrogenic or traumatic. Regional anesthesia is rarely the cause. Recognizing diagnostic features such as the lack of infectious signs and mass compressibility can prevent misdiagnosis and inappropriate invasive treatment.

Traumatic Retropharyngeal Pseudomeningocele with Atlanto-Occipital Dislocation in a Neurologically Intact Patient

Traumatic retropharyngeal pseudomeningoceles occur rarely, are associated with severe trauma, and have been reported in patients with significant neurologic deficits at presentation. We report the rare occurrence of a pseudomeningocele following a high-speed motor vehicle accident. Neurological examination showed the patient to be briskly following commands, with intact cranial nerve, motor, and sensory function. CT/MR imaging showed subarachnoid hemorrhage involving the interpeduncular cistern, a clivus fracture, a right occipital condyle fracture, an atlanto-occipital subluxation, aortic arch transection (stable and contained on CT angiogram), multiple rib fractures on the right side with associated pneumothorax, hemothorax and pulmonary contusions. His cervical spine was stabilized in a halo. He was subsequently managed in the intensive care unit and remained neurologically intact. A repeat MRI showed the interval development of a 2×1.5 cm pseudomeningocele at the craniocervical junction medial to the left occipital condyle communicating with the left anterolateral aspect of the spinal canal. Traumatic pseudomeningoceles are associated with large deceleration forces at the time of injury and are usually associated with significant neurologic deficits at presentation. However, they can arise and give rise to symptoms in a delayed fashion in trauma patients who are neurologically intact at initial presentation.

Early Identification of Traumatic Durotomy Associated with Atlantooccipital Dislocation May Prevent Retropharyngeal Pseudomeningocele Development

Atlantooccipital dislocation can be complicated by a traumatic durotomy that may lead to the rare development of a retropharyngeal pseudomeningocele. To our knowledge this has been reported only five times previously. We present the case of a 60-year-old man involved in a motor vehicle accident who suffered an atlantooccipital dislocation and C5-C6 three-column injury. A unique MRI image of a defect in the ventral dura posterior to C2 was appreciated. He underwent occiput to T2 internal fixation and arthrodesis. During surgery, CSF egress was seen caudal to the right C2 nerve root. A DuraMatrix onlay patch reinforced with DuraSeal was placed to stop the CSF leak. A lumbar subarachnoid drain was also placed. The patient made a satisfactory recovery with residual mild weakness of his right upper extremity. In this report, we demonstrate that careful MRI review can reveal a ventral durotomy in a traumatic atlantooccipital dislocation and, if discovered, effective treatment including a lumbar subarachnoid drain for CSF diversion may prevent progression to a retropharyngeal pseudomeningocele. The literature on this rare presentation and associated durotomy is provided.

Surgical management of chronic traumatic pseudomeningocele of the craniocervical junction: case report

PURPOSE

Chronic traumatic pseudomeningocele (PM) is a rare complication of gunshot injuries of the craniocervical junction in pediatric patients. Impairment of the CSF dynamics may cause severe symptoms and should be treated.

METHODS

We report the case of a 6-year-old girl who was accidentally shot in the neck during tribal clashes. On being admitted, she was neurologically intact with cerebrospinal fluid (CSF) leakage through the wounds. She underwent primary closure of the wounds in a rural medical facility. After two episodes of meningitis, CSF leakage resolved spontaneously. Nine months later, the patient was presented with a disfiguring mass growing in the posterior neck, severe headaches, and constitutional symptoms such as loss of appetite and a failure to thrive.

RESULTS

Neurosurgical intervention was performed with the patient in the prone position. Occipital pericranium graft was used to repair the defect, and the cavity of the PM was obliterated with muscle layers. The patient's symptoms improved at 1 year follow-up without PM recurrence.

CONCLUSION

This is a rare presentation of gunshot injuries in an environment with limited neurosurgical resources. Restoring the normal pattern of CSF circulation should be the aim of any neurosurgical intervention.

Anterior spinal pseudomeningocele after C0-C2 traumatic injuries: role of the "dural transitional zone" in the etiopathogenesis

PURPOSE

Spinal pseudomeningoceles (SPM) are extradural collections of CSF (cerebrospinal fluid); a frequent association with upper cervical injuries (UCI) has been observed. We propose a possible etiopathogenetic mechanism supporting the formation of cervical SPM based on some considerations.

METHODS

We present four cases of SPM. All patients sustained a severe UCI. Three patients were symptomatic with delayed and progressive clinical signs.

RESULTS

One patient was misinterpreted as epidural hematoma and operated on due to progressive signs with postoperative clinical improvement. The rest of patients were treated conservatively; spontaneous reduction of CSF collection occurred. From a radiological standpoint: (1) a line of demarcation separated the intradural cervical compartment from the anterior epidural space, (2) CSF epidural collection was never evident at C0-C2 level and extended from C2 downwards, and (3) shape of collection was similar to epidural hematomas suggesting a ball-valve mechanism.

CONCLUSIONS

The dural layer at C0-C2 level is adherent to the thick ligamentous apparatus, as opposed to the segments below where it is solely covered by the posterior longitudinal ligament. A "transitional zone" of dura exists between the C0-C2 region and subaxial segment of the cervical spine. This watershed area constitutes a point of minor resistance. Lacerations of the meningeal layers, caused by severe UCI at the "transitional zone", drain CSF into the anterior epidural space and form SPM.

Occipitocervical fusion using a contoured rod and wire construct in children: a reappraisal of a vintage technique

OBJECT

Many methods to stabilize and fuse the craniocervical junction have been described. One of the early designs was a contoured (Luque) rod fixated with wires, the so-called Hartshill-Ransford loop. In this study, the authors report their 20-year experience with this surgical technique in children.

METHODS

The authors reviewed the medical records of patients 18 years of age or younger who underwent dorsal occipitocervical fusion procedures between March 1992 and March 2012 at Le Bonheur Children's Hospital using a contoured rod and wire construct. Data on basic patient characteristics, causes of instability, neurological function at presentation and at last follow-up, details of surgery, complications, and radiographic outcome were collected.

RESULTS

Twenty patients (11 male) were identified, with a mean age of 5.5 years (range 1-18 years) and a median follow-up of 43.5 months. Fourteen patients had atlantooccipital dislocation, 2 patients had atlantoaxial fracture-dissociations, 2 had Down syndrome with occipitocervical and atlantoaxial instability, 1 had an epithelioid sarcoma from the clivus to C-2, and 1 had an anomalous atlas with resultant occipitocervical instability. Surgical stabilization extended from the occiput to C-1 in 3 patients, C-2 in 6, C-3 in 8, and to C-4 in 3. Bone morphogenetic protein was used in 2 patients. Two patients were placed in a halo orthosis; the rest were kept in a hard collar for 6-8 weeks. All patients were neurologically stable after surgery. One patient with a dural tear experienced wound dehiscence with CSF leakage and required reoperation. Eighteen patients went on to achieve fusion within 6 months of surgery; 1 patient was initially lost to follow-up, but recent imaging demonstrated a solid fusion. There were no early hardware or bone failures requiring hardware removal, but radiographs obtained 8 years after surgery showed that 1 patient had an asymptomatic fractured rod. There were no instances of symptomatic junctional degeneration, and no patient was found to have increasing lordosis over the fused segments. Five (31%) of the 16 trauma patients required a shunt for hydrocephalus.

CONCLUSIONS

Despite the proliferation of screw-fixation techniques for craniocervical instability in children, the contoured rod-wire construct remains an effective, less expensive, and technically easier alternative that has been in use for almost 30 years. It confers immediate stability, and therefore most patients will not need to be placed in a halo device postoperatively. A secondary observation in our series was the high (30%) rate of hydrocephalus requiring a shunt in patients with traumatic instability.

Pediatric atlanto-occipital dissociation: radiographic findings and clinical outcome

Study design: Retrospective diagnostic feasibility study and clinical review.

Objectives: To evaluate the feasibility of making an initial atlanto-occipital dissociation (AOD) diagnosis from four radiological measurements of the craniocervical relationship on lateral cervical spine x-rays and to assess the AOD patients' clinical outcomes relative to their magnetic resonance imaging (MRI) findings.

Methods: The Powers ratio, Wackenheim line, basion-dens distance (BDD), and the C1/2:C2/3 interspinous ratio were measured in 58 pediatric controls and ten MRI-confirmed patients with AOD. The ability to identify the required anatomical landmarks and make the measurements was noted and sensitivity and specificity calculated. The correspondence between the clinical presentation and outcomes for patients with AOD and their MRI features was investigated.

Results: Clear landmarks for measuring interspinous ratio and Wackenheim line were confirmed by all x-rays. The BDD was measureable in 90% and the Powers ratio could be calculated in only possible in 59%. The interspinous ratio and BDD offered high sensitivities and specificity. Although the Wackenheim line was consistantly measured, it conferred a low sensitivity but reasonable specificity. The Powers ratio offered high specificity with low sensitivity. On MRI, all patients with AOD had apical ligament disruption, with a high rate of interspinous ligamentous injury (8/9); prevertebral swelling (7/9); retroclival hematoma (6/9); and tectorial membrane injury (4/9). The only MRI feature associated with poor outcome was that of altered cord signal. Both patients who died had cord signal changes on T1- and T2-weighted images. The third patient with cord signal change was limited to T2 changes with a normal T1. He had a C5-L3 sensory deficit that resolved. The degree of tectorial membrane injury did not appear to influence outcome.

Conclusions: The BDD and interspinous ratio offer the best measures for initial x-ray diagnosis of AOD. This will alert the surgeon to the need for MRI. These patients often have a reduced level of consciousness, thus making clinical evaluation difficult. The MRI findings, although apparently indicative of severe abnormality, did not actually correspond to outcomes except for the presence of T1 cord signal changes that matched with severe neurological impairment and subsequent death.

Occipitoatlantal dislocation

Occipitoatlantal dislocation (OAD) can be devastating. This injury may be fatal in many cases, but more survivors are reported because of improvements in diagnosis and treatment. This article describes the diagnosis and treatment of OAD. To diagnose and treat OAD appropriately, neurosurgeons must have a detailed understanding of the anatomy of the craniocervical junction. Various radiographic criteria are used to establish the diagnosis of OAD. A destabilizing injury such as OAD requires surgical fixation. Many surgical techniques are available for fixation of the craniocervical junction. Future studies will continue to refine the diagnostic criteria for OAD and to develop improved methods for craniocervical stabilization.

Retropharyngeal pseudomeningocele

A 38-year-old male was found to have a retropharyngeal pseudomeningocele along with C1 - C2 dislocation. Absence of any possible history, misleading circumstantial evidence and rarity of the entity made it impossible to diagnose the condition preoperatively. Concurrent medical problems dominated and the patient died. As a result, outcome of the pseudomeningocele could not be evaluated.

ATLANTO-OCCIPITAL DISLOCATION—PART 2

OBJECTIVE

The diagnosis of atlanto-occipital dislocation (AOD) remains problematic as a result of a lack of reliable radiodiagnostic criteria. In Part 1 of the AOD series, we showed that the normal occiput–C1 joint in children has an extremely narrow joint gap (condyle–C1 interval [CCI]) with great left-right symmetry. In Part 2, we used a CCI of 4 mm or greater measured on reformatted computed tomographic (CT) scans as the indicator for AOD and tested the diagnostic sensitivity and specificity of CCI against published criteria. The clinical manifestation, neuroimaging findings, management, and outcome of our series of patients with AOD are also reported.

METHOD

For diagnostic sensitivity, we applied the CCI criterion on 16 patients who fulfilled one or more accepted radiodiagnostic criteria of AOD and who showed clinical and imaging hallmarks of the syndrome. All 16 patients had plain cervical spine x-rays, head CT scans, axial cervical spine CT scans with reconstruction, and magnetic resonance imaging scans. The diagnostic yield and false-negative rate of CCI were compared with those of four published “standard” tests, namely Wholey's dens-basion interval, Powers' ratio, Harris' basion-axis interval, and Sun's interspinous ratio. The diagnostic value of “nonstandard” indicators such as cervicomedullary deficits, tectorial membrane and other ligamentous damage, perimedullary subarachnoid hemorrhage, and extra-axial blood at C1−C2 were also assessed. For diagnostic specificity, we applied CCI and the “standard” and “nonstandard” tests on 10 patients from five classes of non-AOD upper cervical injuries. The false-positive diagnostic rates for AOD of all respective tests were documented.

RESULTS

The CCI criterion was positive in all 16 patients with AOD with a diagnostic sensitivity of 100%. Fourteen patients had bilateral AOD with disruption and widening of both OC1 joints. Two patients had unilateral AOD with only one joint wider than 4 mm. The abnormal CCI varied from 5 to 34 mm. Eight patients showed blatant left-right joint asymmetry in either CCI or anatomic conformation. The diagnostic sensitivities for the “standard” tests are as follows: Wholey's, 50%; Powers', 37.5%; Harris', 31%; and Sun's, 25%, with false-negative rates of 50, 62.5, 69, and 75%, respectively. The sensitivities for the “nonstandard” indicators are: tectorial membrane damage, 71%; perimedullary blood, 63%; and C1−C2 extra-axial blood, 75%, with false-negative rates of 29, 37, and 25%, respectively. Fifteen patients with AOD had occiput-cervical fusion. There were one early and two delayed deaths (19% mortality); two patients (12%) had complete or severe residual high quadriplegia, but 11 children (69%) enjoyed excellent neurological recovery. CCI was normal in all 10 patients with non-AOD upper cervical injuries with a diagnostic specificity of 100%. The false-positive rates for the four “standard” tests were: Sun's, 60%; Harris', 50%; Wholey's, 30%; and Powers', 10%; for the “nonstandard” indicator, the rates were: cervicomedullary deficits, 70%; tectorial membrane damage, 40%; C1−C2 extra-axial blood, 40%; and perimedullary blood, 30%.

CONCLUSION

The CCI criterion has the highest diagnostic sensitivity and specificity for AOD among all other radiodiagnostic criteria and indicators. CCI is easily computed from reconstructed CT scans, has almost no logistical or technical distortions, can capture occiput–C1 joint dislocation in all three planes, and is unaffected by congenital anomalies or maturation changes of adjacent structures. Because CCI is the only test that directly measures the integrity of the actual joint injured in AOD and a widened CCI cannot be concealed by postinjury changes in the head and neck relationship, it surpasses others that use changeable landmarks.

Retropharyngeal pseudomeningocele formation as a traumatic atlanto-occipital dislocation complication: case report and review

Retropharyngeal pseudomeningocele after atlanto-occipital dislocation is a rare complication, with only five cases described in the literature. It develops when a traumatic dural tear occurs allowing cerebrospinal fluid outflow, and it often appears associated with hydrocephalus. We present a case of a 29-year-old female who suffered a motor vehicle accident causing severe brain trauma and spinal cord injury. At hospital arrival the patient scored three points in the Glasgow Coma Scale. Admission computed tomography of the head and neck demonstrated subarachnoid hemorrhage and atlanto-occipital dislocation. Three weeks later, when impossibility to disconnect her from mechanical ventilation was noticed, a magnetic resonance imaging of the neck showed a large retropharyngeal pseudomeningocele. No radiological evidence of hydrocephalus was documented. Given the poor neurological status of the patient, with spastic quadriplegia and disability to breathe spontaneously due to bulbar-medullar injury, no invasive measure was performed to treat the pseudomeningocele. Retropharyngeal pseudomeningocele after atlanto-occipital dislocation should be managed by means of radiological brain study in order to assess for the presence of hydrocephalus, since these two pathologies often appear associated. If allowed by neurological condition of the patient, shunting procedures such as ventriculo-peritoneal or lumbo-peritoneal shunt placement may be helpful for the treatment of the pseudomeningocele, regardless of craniocervical junction management.

Survivors of occipitoatlantal dislocation injuries: imaging and clinical correlates

OBJECT

Although rare, traumatic occipitoatlantal dislocation (OAD) injuries are associated with a high mortality rate. The authors evaluated the imaging and clinical factors that determined treatment and were predictive of outcomes, respectively, in survivors of this injury.

METHODS

The medical records and imaging studies obtained in 33 patients with OAD were reviewed retrospectively. Clinical factors that predicted outcomes, especially neurological injury at presentation and imaging findings, were evaluated. The most sensitive method for the diagnosis of OAD was the measurement of basion axial-basion dens interval on computed tomography (CT) scanning. Five patients with severe traumatic brain injuries (TBIs) were not treated and subsequently died. Of the 28 patients in whom treatment was performed, 23 underwent fusion and five were fitted with an external orthosis. Abnormal findings of the occipitoatlantal ligaments on magnetic resonance (MR) imaging, associated with no or questionable abnormalities on CT scanning, provided the rationale for nonoperative treatment. Of the 28 patients treated for their injuries, perioperative death occurred in five, three of whom had presented with severe neurological injuries. The mortality rate was highest in patients with a TBI at presentation. The mortality rate was lower in patients presenting with a spinal cord injury, but in this group there was a higher rate of persistent neurological deficits.

CONCLUSIONS

The spines in patients with CT-documented OAD are most likely unstable and need surgical fixation. In patients for whom CT findings are normal and MR imaging findings suggest marginal abnormalities, nonoperative treatment should be considered. The best predictors of outcome were severe brain or upper cervical injuries at initial presentation.

Post-traumatic pseudomeningocele presenting as a cyst of external auditory canal: Report of a case

Pseudomeningoceles are formed by extravasation of cerebrospinal fluid through a dural defect into soft tissue. They mostly form as a result of surgical trauma to the dural covering of the lumbar or cervical spine surgery, especially during laminectomy. Howerver, post-traumatic pseudomeningocele rarely occurs in the head and neck. A 32-year-old female presented with a 10-year history of right ear fullness following head trauma. A soft, non-pulsatile and cystic mass was noted in the right external auditory canal. The MRI scan demonstrated the connection between subarachnoid space and cyst of the right external auditory canal. The right ear was explored and mastoid antrum was partially filled with a cyst connected to the dural defect. The extradural portion of the mass was removed, the dural defect was repaired with a temporalis fascia-cartilage graft. Clinical manifestations, diagnosis and surgical approaches for post-traumatic pseudomeningocele arising in the head and neck region are briefly discussed.

Spinal cord compression from traumatic anterior cervical pseudomeningoceles

✓Pseudomeningoceles rarely develop after cervical trauma; in all reported cases the lesions have extended outside the spinal canal.

The authors report the first known cases of anterior cervical pseudomeningoceles contained entirely within the spinal canal and causing cord compression and neurological injury. The authors retrospectively reviewed the cases of three patients with traumatic cervical spine injuries and concomitant compressive anterior pseudomeningoceles. The lesion was recognized in the first case when the patient’s neurological status declined after he sustained a severe atlantoaxial injury; the pseudomeningocele was identified intraoperatively and decompressed. After the decompressive surgery, the patient’s severe tetraparesis partially resolved. In the other two patients diagnoses of similar pseudomeningoceles were established by magnetic resonance imaging. Both patients were treated conservatively, and their mild to moderate hemiparesis due to the pseudomeningocele-induced compression abated.

The high incidence of anterior cervical pseudomeningoceles seen at the authors’ institution within a relatively brief period suggests that this lesion is not rare. The authors believe that it is important to recognize the compressive nature of these lesions and their potential to cause devastating neurological injury.

Retropharyngeal Pseudomeningocele Presenting as Dysphagia After Atlantooccipital Dislocation

EDUCATIONAL OBJECTIVE

At the conclusion of this paper, the readers should be able to recognize a retropharyngeal pseudomeningocele as a potential complication of atlanto occipital dislocation.

OBJECTIVES

To demonstrate how a retropharyngeal pseudomeningocele may present as dysphagia in a patient who is recovering from atlanto occipital dislocation as well as to discuss the treatment options in this situation.

STUDY DESIGN

Case report and literature review.

METHODS

Analysis of a case through medical record and literature review.

RESULTS

A retropharyngeal pseudomeningocele is a very rare complication of atlanto occipital dislocation. It may develop weeks after the initial injury and can present with respiratory or swallowing difficulties. Decompression via a ventriculoperitoneal or lumboperitoneal shunt facilitates resolution of the cerebral spinal fluid collection.

CONCLUSIONS

A retropharyngeal pseudomeningocele should be considered in all patients status post-atlanto occipital dislocation who are experiencing respiratory distress or dysphagia.

Pediatric spine injuries

Pediatric spine injuries are rare, not only due to the plasticity of the pediatric spine, but also due to the difficulty of diagnosis and the usually severe, if not fatal, associated injuries. Mechanisms of injury, transportation, initial management, diagnostic exams, and management of such lesions are different from those of the adult, and an individualized approach to each case, looking for specific injury patterns, avoids misdiagnosis. The goal of this manuscripts is to summarize the specific spinal injury patterns of the pediatric population, as well as the present literature regarding their diagnosis and treatment.

Tectorial Membrane Injuries in Children

We report three cases of tectorial membrane injury in children. An increased interspinous ratio was identified on cervical spine radiographs. The tectorial membrane injuries were diagnosed by magnetic resonance imaging. The three children were restrained passengers in high-speed motor vehicle accidents, and all sustained polytrauma. Two children with partial tears of the tectorial membrane were immobilized in a halo, and one with a longitudinal tear of the tectorial membrane had an occiput-to-C2 fusion.

Atlanto-occipital dislocation with traumatic pseudomeningocele formation and post-traumatic syringomyelia

STUDY DESIGN

A case report of traumatic atlanto-occipital dislocation complicated by the development of anterior and posterolateral pseudomeningoceles and the late development of syringohydromyelia is presented.

OBJECTIVE

To describe a unique post-traumatic and postsurgical course following atlanto-occipital dislocation.

SUMMARY OF BACKGROUND DATA

Syringomyelia is a significant potential long-term complication in patients recovering from traumatic atlanto-occipital dislocation. Cord enlargement and increased T2 signal can be a marker of abnormal cerebrospinal fluid flow dynamics. This "presyrinx state" can be seen before clinical evidence of neurologic compromise. Pseudomeningocele formation after atlanto-occipital dislocation is rare, with only 3 reported cases. To our knowledge, all reported cases describe retropharyngeal pseudomeningoceles, and posterolateral pseudomeningocele as seen in this case has not previously been described.

METHODS

A single case is reported with an emphasis on the imaging findings related to the patient's subsequent neurologic deterioration.

RESULTS

Following a pedestrian-motor vehicle collision, the patient received initial evaluation and treatment at a local foreign medical facility, where his cervical spine was cleared. Several days following stabilizing treatment and surgery, the patient was transferred to a foreign-based United States military medical facility and ultimately to our institution, where magnetic resonance imaging demonstrated occipitocervical dissociation. The patient was taken to the operating room for surgical stabilization. Four months after his index operation, the patient underwent halo removal. Follow-up magnetic resonance imaging revealed thickening of the cervical spinal cord in conjunction with diffuse high cord T2 signal and a small low cervical segment of syringomyelia. The patient was observed with follow-up magnetic resonance imaging obtained after 1 month. At this time, the low cervical syrinx had enlarged slightly, a small thoracic syrinx was observed, and cine imaging of cerebrospinal fluid flow demonstrated obstruction at the level of the foramen magnum. The patient was taken to the operating room fordecompression of the foramen magnum and posterior fossa and duraplasty. One month later, the patient's clinical condition began to deteriorate, and repeat imaging showed continued enlargement of the patient's syrinx and hydrocephalus. He was admitted for an urgent shunt procedure but unfortunately sustained cardiorespiratory arrest while on the ward awaiting surgery.

CONCLUSIONS

Atlanto-occipital dislocation is rarely survivable, and delayed diagnosis can negatively affect long-term clinical outcome. This case illustrates how, despite early signs of improvement, post-traumatic syringomyelia may occur months or even years after spinal trauma and should always be considered in patients who experience late neurologic deterioration after atlanto-occipital dislocation.

Atlanto-occipital dislocation: four case reports of survival in adults and review of the literature

Traumatic atlanto-occipital dislocation (AOD) is a rare cervical spine injury and in most cases fatal. Consequently, relatively few case reports of adult patients surviving this injury appeared in the literature. We retrospectively report four patients who survived AOD injury and were treated at our institution. A young man fell from height and a woman was injured in a traffic accident. Both patients survived the injury but died later in the hospital. The third patient had a motorcycle accident and survived with incomplete paraplegia. The last patient, a man involved in a working accident, survived without neurological deficit of the upper extremities. Rigid posterior fixation and complete reduction of the dislocation were applied in last two cases using Cervifix together with a cancellous bone grafting. Previously reported cases of patients surviving AOD are reviewed, and clinical features and operative stabilisation procedures are discussed.

Spinal pseudomeningoceles and cerebrospinal fluid fistulas

Spinal pseudomeningoceles and cerebrospinal fluid (CSF) fistulas are rare extradural collections of CSF that result following a breach in the dural-arachnoid layer. They may occur due to an incidental durotomy, during intradural surgery, or from trauma or congenital abnormality. The majority are iatrogenic and occur in the posterior lumbar region following surgery. Although they are often asymptomatic, they may cause low-back pain, headaches, and even nerve root entrapment. Leakage of CSF from the wound may cause a fistulous tract, which is a conduit for infection and should be repaired immediately. Diagnosis can be confirmed on clinical examination or imaging studies including magnetic resonance imaging, computerized tomography myelography, and radionuclide myelography. Treatment must be specific to each patient because the timing, size, symptoms, and location of the dural breach all affect the choice of therapy. Nonsurgical methods may be used, but more frequently operative repair is required. In this article, the authors review the diagnosis and treatment of spinal pseudomeningoceles and CSF fistulas.

Atlantooccipital dislocation in children: presentation, diagnosis, and management

Atlantooccipital dislocation (AOD) injuries are highly unstable, and usually result in significant neurological injury and death. Recently the postinjury survival period has increased. In a review of the literature the authors found 41 cases in which survival was greater than 48 hours. This is likely due to improved on-scene resuscitation, spinal immobilization, transportation, new diagnostic techniques, and a higher index of suspicion.

Diagnosis is usually made with plain cervical radiographs, but there are shortcomings associated with this modality in the pediatric population. Diagnosis is aided by high-resolution computerized tomography and magnetic resonance imaging. Infants and toddlers may undergo orthotic immobilization alone, whereas older children usually undergo early occipital cervical fusion. Those with incomplete AOD may be managed successfully with orthotic immobilization.

Dual-strap augmentation of a halo orthosis in the treatment of atlantooccipital dislocation in infants and young children. Technical note

Two children who were 13 months and 3 years old and who had suffered traumatic atlantooccipital dislocation were each treated by being placed in a halo orthosis for 10 weeks. Because of a continued loss of reduction due to the poor fit of the halo vest, a dual-strap augmentation was developed. This strap augmentation allowed consistent reduction to be maintained. Both children were therefore successfully treated nonsurgically with a halo vest. One child remained neurologically intact and the other had improvement in motor strength. There were no complications from the use of strap augmentation for halo vest fixation.

Diagnosis and management of traumatic atlanto-occipital dislocation injuries

DIAGNOSTIC

STANDARDS

There is insufficient evidence to support diagnostic standards.

GUIDELINES

There is insufficient evidence to support diagnostic guidelines.

OPTIONS

A lateral cervical x-ray is recommended for the diagnosis of atlanto-occipital dislocation. If a radiological method for measurement is used, the basion-axial interval-basion-dental interval method is recommended. The presence of upper cervical prevertebral soft tissue swelling on an otherwise nondiagnostic plain x-ray should prompt additional imaging. If there is clinical suspicion of atlanto-occipital dislocation, and plain x-rays are nondiagnostic, computed tomography or magnetic resonance imaging is recommended, particularly for the diagnosis of non-Type II dislocations.

TREATMENT

STANDARDS

There is insufficient evidence to support treatment standards.

GUIDELINES

There is insufficient evidence to support treatment guidelines.

OPTIONS

Treatment with internal fixation and arthrodesis using one of a variety of methods is recommended. Traction may be used in the management of patients with atlanto-occipital dislocation, but it is associated with a 10% risk of neurological deterioration.

Review of spinal pseudomeningoceles and cerebrospinal fluid fistulas

Spinal pseudomeningoceles and cerebrospinal fluid (CSF) fistulas are uncommon extradural collections of CSF that may result from inadvertent tears in the dural-arachnoid layer, traumatic injury, or may be congenital in origin. Most pseudomeningoceles are iatrogenic and occur in the posterior lumbar region following surgery. The true incidence of iatrogenic pseudomeningoceles following laminectomy or discectomy is unknown; however, the authors of several published reports suggest that the incidence of lumbar pseudomeningoceles following laminectomy or discectomy is between 0.07% and 2%. Pseudomeningoceles are often asymptomatic, but patients may present with recurrence of low-back pain, radiculopathy, subcutaneous swelling, or with symptoms of intracranial hypotension. Very rarely, they present with delayed myelopathy. Although magnetic resonance imaging is the neurodiagnostic study of choice, computerized tomography myelography and radionuclide myelographic study may be helpful diagnostic tools in some cases. Analysis of suspect fluid for Beta2 transferrin may be a useful adjunctive study. Treatment options include close observation for spontaneous resolution, conservative measures such as bed rest and application of an epidural blood patch, lumbar subarachnoid drainage, and definitive surgical repair.

Spectrum of occipitoatlantoaxial injury in young children

OBJECT

Injuries of the occipitoatlantoaxial (Oc-C2) region are the predominant form of cervical injury in children younger than 10 years of age. Magnetic resonance (MR) imaging can be used to visualize directly the traumatic ligamentous and soft-tissue abnormalities of the Oc-C2 region. A retrospective review was undertaken to examine the spectrum of pediatric Oc-C2 injuries seen on MR imaging, their correlation with plain x-ray film and computerized tomography findings, and their clinical course.

METHODS

Seventy-one consecutive children younger than 10 years of age underwent cervical MR imaging for evaluation of traumatic injury. Magnetic resonance imaging was used to document abnormalities in 23 children; 20 of these injuries involved the Oc-C2 region. Abnormalities in the Oc-C2 region included disruptions of the musculature, apical ligament, atlantooccipital joint(s), tectorial membrane, and spinal cord. A spectrum of injury with progressive involvement of these structures was seen, ranging from isolated muscular injury to the multiple soft-tissue and ligamentous disruptions with craniocervical dislocation. Involvement of the tectorial membrane was the critical threshold in the transition from stable to unstable injury. Analysis of plain x-ray films revealed that a novel interspinous C1-2:C2-3 ratio criteria of greater than or equal to 2.5 was predictive of tectorial membrane abnormalities on MR imaging, with 87% sensitivity and 100% specificity. In patients with tectorial membrane abnormalities who underwent immobilization alone, interim platybasia was demonstrated on follow-up MR images. Conclusions. A progressive spectrum of distinct Oc-C2 injuries can occur in young children; the tectorial membrane is a critical stabilizing ligamentous structure in the Oc-C2 complex; and tectorial membrane abnormalities may be identified by a C1-2:C2-3 ratio of greater than or equal to 2.5.