Endoscopic-Assisted Fluorescein-Guided Repair of CSF Rhinorrhea in a Case of Spontaneous CSF Leak

Abstract

Background

Cerebrospinal fluid (CSF) leaks in the form of rhinorrheas and otorrheas are known entities in case of traumatic brain injuries. However, spontaneous CSF leaks are rare in incidence. It happens due to a bony defect at the skull base with an associated breach in the dura and arachnoid layer along with a sinonasal disruption.

Material and Methods

We, at this moment, present the case of a 44-year-old woman with a spontaneous onset CSF rhinorrhea for 1 month.

Observation

She was evaluated with imaging CT cisternography. However, as the defect was small, it was difficult to identify the site of CSF rhinorrhea. Therefore, intrathecal fluorescein dye was administered, and the dye could be visualized with the naked eye under endoscopic white light as a green color after 20 to 30 minutes. The location was identified and was plugged with a Hadad flap and fat plug.

Conclusion

The location of the CSF leak needs to be identified with modalities like CT or MR cisternography, but it becomes challenging if the leak site is small. Hence, the use of intraoperative modalities to determine the location of a leak needs to be done meticulously for a successful outcome.

Keywords

CSF rhinorrhea - fluorescein dye - cisternography - intrathecal dye

Introduction

Cerebrospinal fluid (CSF) leak happens most commonly in patients with traumatic brain injury. It can present in the form of CSF leak from the nose, which is called rhinorrhea, and from the ear as well, which is called otorrhea.[1] Most of the leaks happen due to a communication that occurs between the skull base and the breach in the dura and arachnoid layer resulting in the CSF flowing from a high-pressure zone to outside.[2] The communication can happen from a traumatic injury (70–80%) followed by conditions like intracranial tumors, iatrogenic causes, or spontaneous events. The spontaneous ones are the rare ones where no definite cause was found.[3] [4] Most CSF leaks are resolved on their own with conservative methods. However, there are a few leaks that do not heal or stop on their own. This group of patients will need further evaluation regarding the location, cause of leaks, and management plan. The leaks will cause a persistent hypotension inside the brain cavity, which can lead to symptoms related to it along with risks of retrograde infection of the brain and meninges. Management of such a condition becomes mandatory.[5] [6]

Case Report

We present the case of a 44-year-old woman with a spontaneous onset persistent watery discharge from her right nostril for the past 1 month. Initially, it occurred three to four times a day, worsening on bending forward. Later, the episodes increased to seven to eight times per day with the profuse increase in the quantity and persistence throughout the day. The complaint was affecting her quality of life with avoidance of social gatherings with constant wetting of multiple handkerchiefs. The patient had a few interspersed episodes of nasal blockage on the right side associated with occasional fever, which was low grade and associated with headache. So, suspecting an upper respiratory tract infection, she was started on antibiotics and antihistamines. But the symptoms persisted. Thereafter, she was suspected of a central cause and referred to our institute. She was then investigated with CT cisternography ([Fig. 1]), which revealed “leakage of positive contrast from the right anterior inferior basifrontal region through the cribriform plate.” The exact location and size of the defect, however, could not be appreciated.

Fig. 1 CT cisternography revealing leakage of contrast from the right anteroinferior basifrontal region through the cribriform plate.

The patient was given a trial of conservative management for 3 weeks in the form of bed rest, avoidance of straining, coughing, sneezing, and blowing of balloons with antihistamines, stool softeners, and acetazolamide. However, the symptoms did not resolve.

She was then scheduled for surgery. Expecting difficulty in identifying the location of the defect, we decided to use intrathecal fluorescein to identify the defect intraoperatively. The patient was induced under general anesthesia and placed in the left lateral position. With a spinal needle, a lumbar puncture was done at the level of L3–L4 and 10 mL of CSF was drawn. The spinal needle was left in situ. The CSF was then mixed with 0.2 mL of fluorescein dye (available in the formulation of 500 mg per 5 mL), accounting for a cumulative dose of about 20 mg of fluorescein. This mixture was pushed back into the thecal sac via the existing spinal access, slowly over 10 to 15 minutes. Before the administration of dye, prophylactic antihistamines, and antibiotic injectables were given. Postadministration of dye, the lumbar needle was removed, and the patient was made to lie in the supine position for 30 minutes. The head was then slightly extended and turned 15 degrees toward the surgeon. Cotton swabs imbibed with 4% lidocaine and oxymetazoline were placed in both nostrils for 3 to 5 minutes to anaesthetize and absorb excess secretions. Once clean, a 0-degree white light endoscope was introduced into both nasal cavities and nasopharynx, after 30 minutes of intrathecal administration of dye. The middle turbinate was retracted laterally, maintaining sterile sites. The opening was not visualized in the initial assessment of the nasal cavity. However, with the dye, the opening was identified as a site from where dye was leaking from the skull base near the sphenoethmoidal recess ([Fig. 2]). Even the cotton swabs used to clean were checked for signs of fluorescein. Then, a Hadad flap was taken along with an abdominal fat. Both were used to plug the defect ([Fig. 3]). Then, methyl-acrylate glue was used to fix the flap, and the site was reexamined for any leaking dye. The post-op period of the patient was uneventful. She was then shifted to the recovery room and all her vitals were checked. As she regained consciousness, swabs were tested, and were nil of any dye leakage. She was observed for 3 to 4 days and discharged. She was kept on bed rest with a strict head elevation to about 30 to 45 degrees for the next 2 to 3 weeks with antibiotics, antihistamines, acetazolamide, and stool softeners. She was told not to strain for the next 2 to 3 weeks. She was followed up regularly for 4 months and was investigated via CT imaging for any leaks from the site because re-leakage was the most expected complication. But there was never any evidence of leakage recurrence. Hence, the intrathecal fluorescein-guided endoscopic CSF rhinorrhea repair was deemed successful.

Fig. 2 The dye can be seen leaking from the skull base near the sphenoethmoidal recess.

Fig. 3 The Hadad flap with abdominal fat used to plug the defect.

Discussion

CSF leak is a condition associated usually with traumatic head injuries. Other less common conditions associated with CSF leaks are congenital, intraoperative injuries, intracranial tumors, and, less commonly, spontaneous leaks without any cause. Idiopathic intracranial hypertension, obesity, and hydrocephalus are a few primary causes of spontaneous CSF leaks. Previous history of spinal taps, spinal catheters, or spinal punctures are other important causes. Spontaneous CSF leak is known to have an occurrence of 5 per 100,000 per year, with a female predominance.[7] Spontaneous healing occurs in 70 to 80% of patients within 1 week and in 20 to 30% of patients within a few months.[8] [9] However, in 3 to 4% of cases where they do not resolve, the leaks need to be surgically managed. If left untreated, CSF leak can cause meningitis, low-pressure headaches, pneumocephalus, seizures, and auditory loss.[10] [11] Hence, before surgical intervention, imaging is needed to identify the location and size of the defect, in the form of either CT cisternography or MR cisternography (more sensitive and specific than CT). Other ways to identify the site of the leak include radionucleotide study or fluorescence imaging.[12] Hegazy et al[13] suggested that endoscopic endonasal surgery provided easier access to the anterior and middle skull base without traversing any major neurovascular structures (which was responsible for significant morbidity and mortality).

Real-time intraoperative navigation systems are a new technology that process preoperatively acquired CT and MR images. Fluorescence molecular endoscopy or fluorescence imaging is known for its high sensitivity, specificity, and resolution. It is based on the molecular absorption of light, when electrons go from an excited state to the ground state with the emission vibration loss shifting to longer wavelengths than the excitation spectrum, known as the “Stokes shift.” This downshift wavelength is the one that is recorded. This imaging gives a broad idea of the site and size of the defect so that there are fewer complications and a more precise approach.[14] [15] This can be used to further plan the modality of treatment. Smaller defects at the cribriform, sphenoid, paraseptal, and ethmoidal plate can be managed endoscopically; however, larger ones (>5 cm) or multiple defects in the skull base should be preferably managed by the open method.[16] Identification of the defect in the intraoperative period is important. The use of different modalities like high-resolution CT provides great bony detail, but there is a difficulty in differentiating paranasal secretions from CSF leaks. MRI is an excellent modality for localizing the site of the leak but has poor bony and spatial resolution. Fluorescein imaging is a newer and easier way to identify the location.[17] [18]

When the fracture is less than 1 cm in length, linear, and not associated with intracranial complications, conservative management is followed. If spontaneous fibrosis does not occur, then surgery is required. Surgical intervention methods can be categorized into three different approaches (open intracranial, extracranial non–endoscopic-endonasal, and endoscopic extracranial) depending on the size, location, recurrence, meningocele or meningoencephalocele, and overall condition of the patient. Intrathecal fluorescein helps for improved visualization and localization of CSF leaks intraoperatively and also subsequent assessment of recurrent leaks following repair.[7] [19] Fluorescein is not yet approved by the FDA due to the risks involved like meningitis and seizures. However, the incidence is quite low. It is cheap and easily available. The dye can be seen with white light endoscopy after 30 minutes. In large defects, the dye can be seen as a green color leaking from the site of the defect. In small ones, the defect will be difficult to identify. A blue filter can be used to identify the location. The defects can be closed with free flaps, fat plugs, Hadad flaps, etc.[20] [21] The chance of recurrence of leaks can occur with the size of the defect. The larger the defect, the higher the chance of recurrence. The identification of the site is a must for the successful outcome of the surgery. The endoscopic approach was started in the late 1980s and is slowly gaining popularity. The use of dye is a helpful modality in identifying the exact location of the defect. This decreases the rate of recurrence in such patients if done meticulously.[22] Fluorescein-guided endoscopic endonasal surgery is showcasing a promising role in the future. With further integration of artificial intelligence and augmented reality, it is expected to further improve the accuracy and safety of surgeries. There are many ongoing research studies for validating the new fluorescence agents and their safety.[7] [19] [Table 1] shows a list of a few endonasal CSF leak repairs of a total of 141 patients, with/without fluorescein dye usage, which shows a female preponderance with almost zero CSF recurrence leakage on fluorescein dye usage.

Table 1 List of few endonasal cerebrospinal fluid (CSF) leak repairs with/without fluorescein dye usage

Sl. no.	Study references	No. of patients	Male:female ratio	Fluorescein dye used	Post-op CSF leak (%)
1	Basu et al 2006	8	Unknown	No	12.5
2	Fyrmpas et al 2014	11	8:3	No	9.1
3	Sannareddy et al 2014	11	9:2	No	18.2
4	Lieberman et al 2015	44	35:9	Yes	0
5	Martínez-Capoccioni et al 2015	25	20:5	No	4
6	Emanuelli et al 2015	10	9:1	Yes	0
7	Ziade et al 2016	10	8:2	Yes	0
8	Nix et al 2016	7	Unknown	Yes	0
9	Sarkar et al 2016	5	3:2	Yes	0
10	Kljajic et al 2016	10	7:3	Yes	0

Conclusion

The spontaneous type of CSF rhinorrhea is the least common type of CSF leak. In our case, the defect was not properly identifiable in CT cisternography, and intrathecal fluorescein was used intraoperatively to identify the exact location of the defect. The location of the CSF leak needs to be identified with modalities like CT or MR cisternography, but it becomes challenging if the leak site is minimal. Hence, the use of intraoperative modalities to identify the location of a leak needs to be done meticulously for a successful outcome. This is a procedure that can be streamlined for more CSF leak procedures and can become the gold standard for an endoscopic repair of CSF rhinorrhea in the long run.

Conflict of Interest

None declared.

Acknowledgment

We thank the SOA University for the unconditional support.

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Publication History

Article published online:
02 April 2025