Arachnoid cyst of the fallopian canal and geniculate ganglion area: our experience of 9 cases

Management of Fallopian Canal Spontaneous CSF Leaks, Implications of Elevated Intracranial Pressure: Case Report and Systematic Review of the Literature

OBJECTIVES

Describe the diagnosis and management of a spontaneous cerebrospinal fluid leak (sCSF-L) through the facial nerve fallopian canal and determine the role of intracranial hypertension (IH).

STUDY DESIGN

Retrospective case study and systematic review of the literature.

METHODS

Reviewed patient characteristics, radiographic findings, and management of the facial nerve canal CSF leak and postoperative IH. Conducted systematic literature review according to the PRISMA guidelines for surgical management and rates of IH.

RESULTS

A 50-year-old female with bilateral tegmen defects and temporal encephaloceles underwent left middle cranial fossa (MCF) repair. Intraoperative CSF egressed from the temporal bone tegmen defects. Facial nerve decompression revealed CSF leak from the labyrinthine segment. A nonocclusive temporalis muscle plug was placed in the fallopian canal, and tegmen repair was completed with bone cement. A ventriculoperitoneal shunt was placed for IH. Postoperative facial nerve function and hearing were normal. A total of 20 studies met inclusion criteria with a total of 25 unique patients. Of 13 total adult cases of fallopian canal CSF leak, there is a 46% recurrence rate, and 86% of patients had documented IH when tested.

CONCLUSIONS

Fallopian canal CSF leaks are rare and challenging to manage. Assessment of intracranial hypertension and CSF diversion is recommended along with MCF skull base repair to preserve facial nerve function and conductive hearing.

Fallopian canal arachnoid cyst with acute facial nerve paralysis in children: a report of two cases and literature review

Introduction

Symptoms induced by arachnoid cysts in the fallopian canal are uncommon, and facial nerve paralysis without cerebrospinal fluid otorrhea is comparatively rarer.

Methods

Herein, we present two cases of arachnoid cysts in the fallopian canal with acute severe facial nerve paralysis and review the relevant literature.

Results

The symptoms and imaging findings of these two cases resembled those of facial nerve schwannomas. Cerebrospinal fluid otorrhea occurred upon removal of the arachnoid cyst, and the facial nerve was observed to be separated into multiple filaments or compressed and atrophied. Facial-hypoglossal nerve anastomosis and decompression were conducted after packing the dehiscence of cerebrospinal fluid otorrhea for the two cases.

Conclusion

Arachnoid cysts of the fallopian canal rarely cause facial nerve paralysis. Enhanced magnetic resonance imaging is vital for differentiating schwannomas. Different treatment strategies should be adopted for patients with different degrees of facial nerve paralysis; however, concurrent repair of cerebrospinal fluid otorrhea and facial nerves during surgery can occasionally be challenging.

Perigeniculate arachnoid cysts and CSF fistulae of the fallopian canal: Histopathologic correlates of a rare clinical entity

Cerebrospinal fluid (CSF) fistulae originating from the fallopian canal of the facial nerve is hypothesized to arise due to atypical patterns of subarachnoid space extension into the geniculate ganglion or more distal regions along the intratemporal course of the facial nerve, but its pathogenesis remains poorly understood. Although a rare etiology of CSF fistulae of the temporal bone, there are significant clinical ramifications due to the risk of recurrent meningitis, difficulty in identifying the anatomic location of the CSF leak, and technical challenges associated with surgical repair. We present three clinical cases of arachnoid cysts within the geniculate fossa with or without CSF fistulization and provide histopathologic correlates of this rare clinical phenomenon from a human temporal bone collection. The pediatric and adult patients presented suggest differential pathophysiologic mechanisms associated with CSF fistulae. Temporal bone histology reveals atypical patterns of subarachnoid space extension in the fallopian canal that may underlie arachnoid cyst formation and overt CSF leak from the geniculate region.

Radioanatomic Assessment of the Geniculate Ganglion Dehiscence and Dimension: A Cadaveric Study

OBJECTIVE

The main aim of this study placed on cadavers was to compare the data related to geniculate ganglion (GG) dehiscence and dimension obtained from computed tomography (CT) with dissection values.

METHODS

This study was conducted on 20 temporal bones obtained from 10 cadavers (4 female, 6 male) aged between 45 and 92 (71.50 ± 15.98) years. All the measurements related to GG dimension were performed with a CT scanner and microdissection.

RESULTS

The size of GG including its area, length, and width did not show statistically significant differences in terms of sex, side, and assessment method (CT and cadaveric dissections). The dehiscent GG was observed in 6 (30%) and 5 (25%) out of 20 temporal bones in CT and cadaveric dissections, respectively. The presence and absence of GG dehiscence in CT and dissection were similar in 75%.

CONCLUSIONS

Our findings based on dissection data suggest that radiologic evaluation of dehiscent GG detection might be erroneous by 25%, which highlights that surgeons should be careful when lifting the dura to prevent GG injury during middle cranial fossa surgical approaches. On the other hand, there was no statistical difference between CT and dissection measurements related to GG dimension.