Keywords
Cervical spine - pseudomeningocele - retropharyngeal
Introduction
A pseudomeningocele develops as a result from a tear of the dura, leading to the accumulation
and extravasation of cerebrospinal fluid (CSF). These lesions are typically iatrogenic,
a complication from spinal surgery.[1]
[2] A retropharyngeal pseudomeningocele after cervical vertebral dislocation is an extremely
rare complication and often appears associated with hydrocephalus.[1] It usually appears in delayed fashion some weeks after initial trauma and usually
presents as respiratory difficulty or dysphagia, although sometimes it can be an incidental
finding in a radiological study.[3] We reported a relatively rare case of posttraumatic anterior cervical prevertebral
retropharyngeal pseudomeningocele with no associated hydrocephalus, which was found
incidentally in radiological study.
Case Report
A 45-year old female patient presented to neurosurgery emergency department with an
alleged history of road traffic accident and cervical trauma. On neurological examination,
she had Glasgow Coma Scale (GCS) score of 15 and complete spinal cord injury below
C5 level (American Spinal Injury Association [ASIA] grade A) with abdominothoracic
breathing pattern. Imaging (X-ray, CT) showed C6-C7 bilateral facet dislocation with
fracture of posterior elements of C5 and C6 and chip fracture of anterosuperior part
of C7 body ([Fig. 1]). MRI demonstrated complete cord transection at the level of C6-C7, with cord contusion
extending from C4 to C7, and CSF collection in prevertebral retropharyngeal space
extending from C7 to T2 ([Fig. 2]). Close manual reduction was done under general anesthesia, and patient underwent
C6-C7 anterior cervical discectomy and fusion (ACDF) ([Fig. 3]). Intraoperatively, on removing the chip fracture segment of C7 body, gush of CSF
came out; then, C6-C7 discectomy was done and no dural tear was seen. However, on
doing Valsalva maneuver, CSF was found coming from left lateral aspect of dura at
C6-C7 level. Fibrin glue with fat graft was applied; after which, no CSF leak was
observed. Postoperative period was uneventful; drain was removed on postoperative
day 7, and no CSF leak was found through sutured wound. Unfortunately, patient went
into respiratory failure and expired after 2 weeks postoperatively.
Fig. 1 CT cervical spine suggestive of anterolisthesis of C6 over C7 with spinous process
fracture of C5-C6.
Fig. 2 MRI cervical spine. (A) Sagittal imaging showing cord contusion and prevertebral retropharyngeal pseudomeningocele.
(B) Axial imaging showing avulsed left C6 nerve roots with prevertebral cerebrospinal
fluid (CSF) collection.
Fig. 3 Postoperative X-ray showing plate and screw in situ with reduction of subluxation.
Discussion
Pseudomeningocele is an extradural collection of CSF which diverts through a dural
tear, and the most common etiology is iatrogenic, especially as a consequence of lumbar
spine surgery, cervical spine surgery, posterior fossa surgery, or lumbar puncture.[4]
[5]
[6] Less frequently are traumatic and congenital causes. Posttraumatic pseudomeningoceles,
usually in the posterior spinal region, are rare complications of root avulsions,
fractures and dislocations of vertebrae, and minor traumas, often located in the lumbar
spine.[4]
[6]
[7] While posttraumatic pseudomeningocele is rare, a prevertebral retropharyngeal pseudomeningocele
is believed to be extremely rare, the incidence of which is not clear due to its rarity,
and is usually associated with cervical trauma. To the best of our knowledge, we found
only 10 reported cases of retropharyngeal pseudomeningocele, seven of them as a sequalae
of atlanto-occipital dislocation (AOD), two of them as case of atlantoaxial dislocation,
and one of them as a case of C5-C6 subluxation ([Table 1]).[1]
[3]
[8]
[9]
[10]
[11]
[12]
[13]
[14] To our knowledge, this is the second reported occurrence of a prevertebral retropharyngeal
pseudomeningocele, following dislocation of the lower cervical spine.
Table 1
Reported cases of posttraumatic retropharyngeal pseudomeningocele
|
S. no.
|
Authors
|
Age/sex
|
Etiology
|
Symptoms
|
Hydrocephalus
|
Treatment
|
Outcomes
|
|
1.
|
Williams et al[12]
|
3.5/M
|
AOD
|
Respiratory + dysphagia
|
Yes
|
Cervical fusion + VP shunt
|
Resolution
|
|
2.
|
Naso et al[11]
|
26/M
|
AOD
|
Respiratory + dysphagia
|
Yes
|
VP shunt
|
Resolution
|
|
|
11/M
|
AOD
|
Respiratory
|
Yes
|
−
|
Died
|
|
3.
|
Natale et al[7]
|
33/M
|
Transient C1-C2 dislocation
|
Respiratory + dysphagia
|
Yes
|
LP shunt
|
Resolution
|
|
4.
|
Reed et al[9]
|
9/M
|
AOD
|
Incidental
|
No
|
fixation
|
died
|
|
5.
|
Cognetti et al[10]
|
19/M
|
AOD
|
Dysphagia
|
No
|
LP shunt
|
Resolution
|
|
6.
|
Achawal et al[13]
|
38/M
|
C1-C2 dislocation
|
Quadriplegia
|
No
|
Halo traction
|
Died
|
|
7.
|
Gutiérrez et al[3]
|
29/F
|
AOD
|
Respiratory
|
No
|
−
|
Died
|
|
8.
|
Louati et al[1]
|
64/M
|
C5-C6 bilateral facet dislocation
|
Incidental
|
No
|
Halo traction
|
Died
|
|
9.
|
Alotaibi et al[14]
|
21/M
|
AOD
|
Dysphagia
|
Yes
|
Dural defect repaired + EVD
|
Resolution
|
|
10.
|
Present case
|
45/F
|
C6-C7 bilateral facet dislocation
|
Incidental
|
No
|
ACDF
|
Died
|
Abbreviations: ACDF, anterior cervical discectomy and fusion; AOD, atlanto-occipital
dislocation; EVD, external ventricular drainage; LP, lumboperitoneal; VP, ventriculoperitoneal.
Trauma can cause a nerve root avulsion, a joint dislocation, or a vertebral fracture
that, at the same time, originates from a dural tear, which offers low resistance
and helps CSF outflow to surrounding soft tissues, leading to pseudomeningocele formation.[4]
[6] If hydrocephalus is present, as observed in four of the seven cases previously reported
of retropharyngeal pseudomeningocele secondary to AOD, increased CSF pressure may
force its diversion through dural tear and leads to pseudomeningocele formation.[9]
[11]
[12] In our case, dural tear was not found, but CSF came out from right lateral aspect
of dura at C6-C7 level on applying Valsalva maneuver.
Retropharyngeal pseudomeningocele usually appears in delayed fashion, days to weeks
after the initial trauma. Symptoms often derive from the mass effect when the cyst
reaches significant size. The most common initial symptoms are respiratory failure
and dysphagia, although sometimes the cyst is an incidental finding in a radiological
study performed for a different purpose.[3] In our case, patient is having abdominothoracic breathing pattern, and considering
the radiological findings, it seems reasonable to consider cord contusion as the cause
of the respiratory difficulty, and the prevertebral retropharyngeal pseudomeningocele
in our case can be considered as an incidental finding in the radiological study conducted
prior to the surgery.
MRI is superior to CT in terms of diagnosing spinal cord and soft-tissue injuries;
therefore, it is considered the main diagnostic procedure to confirm the presence
of retropharyngeal pseudomeningocele. Pseudomeningocele is characteristically identified
as a cystic collection with signal intensity consistent with CSF on all sequences.
Other studies such as CSF flow imaging or CT myelography can be helpful to identify
the communication between the cyst and subarachnoid space in those cases where conventional
MRI yields negative.[4]
[6] Once the diagnosis is confirmed, performing a cranial neuroimaging study is recommended
to assess for the presence of hydrocephalus, as these two pathologies often appear
associated.[3] However, CT of the brain ruled out the presence of concomitant hydrocephalus in
our case.
Retropharyngeal pseudomeningocele can be managed either conservatively or surgically.
Conservative management such as bed rest, head of bed elevation, and acetazolamide
and/or osmotic diuretics may be initially attempted. Nevertheless, this therapeutic
option failed in those cases reported by Natale et al. and Cognetti et al.[7]
[10] Surgical alternatives include ventriculoperitoneal shunt in the presence of hydrocephalus,
lumboperitoneal shunt in the absence of hydrocephalus, removal of collection, and
direct repair of defect.[3] However, surgical repair of retropharyngeal pseudomeningocele was challenging for
some cases, because of the following: difficulty in approaching the site of the defect,
increased risk of developing meningitis, or severe morbidity such as poor neurological
function.[14] Alatoibi et al reported the first case of direct repair of defect using muscle graft
and TISSEL fibrin sealant.[14] In the present case, there were no direct visual evidence of dural tear, and CSF
was seen only on Valsalva maneuver; therefore, the repair was done using fat graft
and TISSEL fibrin sealant at C6-C7 level after discectomy followed by C6-C7 fusion.
Conclusion
Posttraumatic lower cervical prevertebral retropharyngeal pseudomeningocele is a rare
complication. The prognosis and outcome of such an entity depends upon the severity
of initial trauma. However, early recognition and management can avoid delayed complications
like enlargement of cyst, which may lead to respiratory distress and dysphagia.
