Endoscopic Treatment of Fluid Fistula Leak: An Analysis of 15 Cases

Abstract

Objectives

Analyze the effectiveness of the endoscopic endonasal surgical technique for the management and treatment of CSF fistulas by comparing data from literature and the authors' casuistry.

Materials and Methods

This is a retrospective study that included fistula leaks surgically treated by endoscopic approach between 2001 and 2020. In addition, a thorough clinical history, a complete otorhinolaryngological examination, clinical neurological evaluation, and endoscopic evaluation of the nasal cavity, are complemented by laboratory and image tests of the research's population.

Results

All 15 fistulas from the population were spontaneous and not associated with any other etiology, with most of the fistulas being in the fovea ethmoidalis and the cribriform plate. During the endoscopic approach, there were no major complications and blood loss was not reported. Only two presented recurrences of the nasoethmoidal fistula were reoperated, through the endoscopic approach, with no more recurrences reported. About their symptomatology, all patients presented with headache, rhinoliquorrhea, and neck stiffness.

Conclusion

Based on what was presented in this article, the endoscopic surgical repair approach proved to be satisfactory as the results were in line with the literature.

Level of evidence: III – retrospective cohort study.

 

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Resumo

Objetivos

Analisar a efetividade da técnica cirúrgica endoscópica endonasal no manejo e tratamento das fístulas liquóricas, comparando dados da literatura e da casuística dos autores.

Materiais e Métodos

Trata-se de um estudo retrospectivo que incluiu fístulas tratadas cirurgicamente por via endoscópica entre 2001 e 2020. Além disso, história clínica minuciosa, exame otorrinolaringológico completo, avaliação neurológica clínica, avaliação endoscópica da cavidade nasal, complementada por exames laboratoriais e de imagem da população da pesquisa.

Resultados

Todas as 15 fístulas da população foram espontâneas e não associadas a nenhuma outra etiologia, sendo a maioria das fístulas localizada na fóvea etmoidal e na placa cribriforme. Durante a abordagem endoscópica, não houve complicações maiores e a perda sanguínea não foi relatada. Apenas dois apresentaram recidivas da fístula nasoetmoidal e foram operados, por via endoscópica, não havendo mais recidivas relatadas. Quanto à sintomatologia, todos os pacientes apresentavam cefaleia, rinorreia e rigidez de nuca.

Conclusão

Com base no que foi apresentado neste artigo, a abordagem cirúrgica endoscópica do reparo mostrou-se satisfatória, pois os resultados foram condizentes com a literatura.

Nível de evidência: III – Estudo coorte retrospectivo

 

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Keywords

fluid fistula leak - endoscopic - surgery

Palavras-chave

fístula liquórica - endoscopia - cirurgia

Introduction

The cerebrospinal fluid (CSF) corresponds to plasma's ultrafiltrate or to lymph, which circulates throughout the subarachnoid space of the central nervous system (CNS) providing physical support and balance for the brain and spinal cord, as well as contributing to the homeostasis' maintenance of nervous tissues, removing molecules which are results from metabolism and maintaining the chemical equilibrium of CNS. It is produced in the plexus choroid of the ventricular system and drained in the arachnoid granulations (structures that have an intimate relation with the dura mater's sinus).[1]

The CSF leak is the result of defects in the dura mater that enable part of the cerebrospinal fluid to not be drained for arachnoid granulations but for the extracranial region. Such involvement becomes potentially fatal due to the great capacity that this fistulation has in taking microorganisms to the CNS and producing meningitis. It has been described that 10 to 40% of patients with cerebrospinal fluid fistula develop meningitis.[2] [3] [4]

Revisions about the basis of dura mater defects' regeneration, which were followed by experiments in the area have led to the conclusion that fibroblasts and connective tissue that regenerate this meninge result in injuries near soft tissuesfrom adjacent tissues (epidural space, fascia, muscle, and subcutaneous tissue). It was concluded, therefore, that the dura mater's regeneration is inefficient when the defect is adjacent to the bone, in contrast to dural injuries near soft tissues. This situation often occurs at the base of the skull.[5]

The aim of this paper is to analyze the effectiveness of the endoscopic endonasal surgical technique for treating cerebrospinal fluid fistulas, by comparing data from literature and the authors' casuistry.

 

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Materials and Methods

This is a retrospective study that included CSF leaks surgically treated, by endoscopic approach, between 2001 and 2020. The population is constituted of 15 patients, five males and ten females.

In addition, a thorough clinical history, a complete otorhinolaryngological examination, clinical neurological evaluation, and endoscopic evaluation of the nasal cavity, complemented by laboratory tests (glucose and beta-2 transferrin) and imaging tests such as Nuclear Magnetic Resonance (NMR) and multi-slice Computed Tomography (CT) were carried out.

In particular, the hypodense fluorescein technique was used. This solution is obtained by diluting 0.5cc of 5% fluorescein in 10ml of distilled water. The patient underwent lumbar puncture at L3-L4 or L4-L5, after which an epidural catheter was inserted about 15cm into the patient's spine and fixed to the skin for 48 hours, to maintain mild cerebrospinal fluid hypotension in the postoperative period. In addition to allowing good visualization of the fistula site, the technique described avoids positioning the patient in the Trendelenburg position, as is done in the hyperdense technique.

We used the following technique in our series:

• The patient is placed in dorsal decubitus under general anesthesia.

• ceftriaxone, 1g IV, is administered 1 hour before the procedure, as meningitis profilaxy.

• Lumbar puncture at L3-L4, with the placement of an epidural catheter, for injection of 5% fluoroscein diluted in 10 ml of double-distilled water, to obtain a hypodense solution. It is important to notify you that immediately after the procedure, the epidural catheter is removed. ([Figs. 1] and [2])

• Localization of the lesion site with 30-degree or 45-degree endoscopes, in the case of lamina crivosa or lateral lamella fistulas; an ethmoidectomy is necessary to better localize the fistulous tract. Occasionally, it may be necessary to perform a resection of the meatal aspect of the middle turbinate, which can be used to form a pedicled flap of the middle turbinate itself. In septal deviations that make it difficult to see the fistulas properly, septoplasty may be necessary.

• Scarification of the surrounding mucosa in a perimeter of 5mm around the fistula to make it easier to take the graft. Grafts of middle turbinate mucosa, septal mucosa, fascia lata, or freeze-dried dura can be used. The use of Duragen, a dural substitute, had a major role in sealing the dura-mater defects. In cases of larger ones, septal cartilage can be used as a support to reinforce the anterior skull base. The use of fibrin glue and Surgicel is important to completely seal off the flow of cerebrospinal fluid.

• Use of ceftriaxone, 1g, every 12 hours, for 5 days after surgery, for meningitis prophylaxis.

• Hospital discharge 48 hours after surgery, after reviewing the nasal cavity with an endoscope.

Figs. 1 and 2 The visualization of fluid fistula leak colored in green by the use of fluorescein in the endoscopic view.

Surgical Techniques

Underlay Approach:

The Underlay technique involves the exact location of the fistula and scarification, elevating the dura adjacent to the fistula site, which in most cases causes slight bleeding due to the detachment of the dura. It is necessary to create a free area to fit the graft, which will be positioned inside the inner edge of the hole, above the defect in the anterior skull base. In the case presented, when using this technique in ethmoidal fistulas with dural defects larger than 1cm, in addition to free flaps of inferior turbinate, septal cartilage was also used to provide more support and prevent recurrences. After positioning the flaps, fibrin glue and Surgicel were applied to completely seal the defect.

 

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Onlay Approach:

In the Onlay technique, after locating the site of the lesion, the mucosa around the fistula is scarified to a perimeter of 5mm. This increases the flow of cerebrospinal fluid but allows the formation of a raw area that facilitates the adhesion of the graft. After placing the graft, fibrin glue and Surgicel are applied to small defects. In larger defects, free grafts of septal mucosa or inferior turbinate were used. In the case of cribriform lamina fistulas, pedicled flaps of the middle turbinate were used. In large fistulas formed by the resection of skull base tumors, we used fascia lata, because as well as being resistant and malleable, it provides a more generous amount of material when compared to grafts resected from the nasal cavity.

 

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Results

A total of 15 patients formed our population. The current data was collected from the period of December 2001 to December 2020. Among those, five patients were male and ten female. The age of our population varies from 17 to 84 years (mean age 50.5 years). All the fistulas were spontaneous, with no related etiology. There were seven patients presenting fluid nasoethmoid fistula situated on the fovea ethmoidalis, six on the cribriform plate, one on the sphenoidal sinus roof, and one situated on the sphenoidal sinus and cribriform plate, simultaneously. ([Table 1]) About their symptomatology, all patients presented with headache, rhinoliquorrhea, and neck stiffness. ([Fig. 3]) Of the total, only five cases were presented with fever. Three cases were initially diagnosed as meningitis, although, with further investigations, it was possible to conclude that the spontaneous fistulas were responsible for their symptomatology.

Fig. 3 Visualization of rhinoliquorrhea in the physical examination.

Table 1 Baseline characteristics of population

Casuistry from 2001 to 2020
Total: 15 cases
Male Gender: 5	Female Gender: 10
Etiology:
Spontaneous	15
Location:
Fovea ethmoidalis	7
Cribriform plate	6
Esphenoidal Sinus Roof	1
Sphenoidal sinus and Cribriform plate	1
Recurrences: 2
Recurrent Meningitis: 2

During the endoscopic approach, there were no major complications and blood loss was not reported. The mean time of the procedure was 1 hour and 45 minutes. Nine patients proceeded with the underlay technique, and six underwent the onlay technique.

Only two patients presented post-operative complications such as meningitis. Those were properly treated. At last, only two presented recurrences of the nasoethmoidal fistula and were reoperated, through the endoscopic approach. To this date, no other recurrences have been reported.

 

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Discussion

The first description of a rhinogenic cerebrospinal fluid fistula was made by Galen in 200 BC.[6] [7] In 1826, Miller described a fistula located between the nasal cavity and the subarachnoid space in a child with hydrocephalus with a history of intermittent nasal discharge during a necropsy.[8] In 1889, Saint Clair Thompson reported a series of patients with spontaneous rhinogenic CSF leak.[6] [7]

The CSF fistulas can be classified as congenital or traumatic; however, when no apparent cause is present, the fistula is described as spontaneous. Spontaneous CSF fistulas are more common in patients with obesity and idiopathic intracranial hypertension (ICH).[9]

The traumatic etiology is the main cause of cerebrospinal fluid leakage (80-90% of cases), followed by iatrogenic (10%), spontaneous (3-4%), tumor, and inflammations.[10]

Spontaneous CSF fistulas are typically observed in the anterior and lateral regions of the skull base, with the dura mater rupturing in areas over a pneumatized space. The incidence of spontaneous CSF fistulas is higher in females (72%).[11]

Patients with spontaneous CSF leak often exhibit a thinning of the base of the skull. This condition is more prevalent in middle-aged and older women, potentially due to the fact that women have thinner bones, increasing their susceptibility to bone erosion. In women, skull thickness diminishes with age, in contrast to the observed trend in men.[12]

In addition to a comprehensive clinical history and a detailed otorhinolaryngological examination, a full clinical neurological evaluation and an endoscopic examination of the nasal cavity are essential components of the diagnostic process. Laboratory tests, such as glucose and beta-2 transferring, and imaging examinations, including magnetic resonance imaging (MRI) and multi-slice computed tomography (CT), are also crucial for complete assessment.[9]

Locating exactly the fistula is extremely important, seeing this precise identification is paramount for therapeutic efficacy. One of the alternatives to be used is multi-slice tomography that through three-dimensional reconstruction facilitates the detection of the exact place of the lesion, allowing sagittal incisions to detect faults in the roof of the sphenoid sinus.[13]

The accuracy of preoperative methods capable of locating the site of nasal congestion is essential for surgical treatment.[14] [15] Nasal congestion can develop in any of the paranasal sinuses: frontal, ethmoid, or sphenoid. There is also a particular case called paradoxical, in which the CSF exits into the middle ear through the auditory tube.[16]

Persistent rhinorrhea in patients with CSF leak is a medical condition that can lead to meningitis in 19% of cases. In many cases, the treatment of choice is endoscopic surgery for closure, which has been demonstrated to be an effective method of reducing the risk of meningitis. The prophylactic use of antibiotics may also be an effective method of reducing this risk.[10] [17]

It is well established that ICH can result in spontaneous CSF rhinorrhea, given the established link between this condition and the occurrence of ICH. Consequently, it is recommended that ICH be managed with the use of Acetazolamide (AAZ), which was the first non-mercurial diuretic to be introduced for clinical use in 1954. Subsequent studies have demonstrated the efficacy of AAZ in the treatment of idiopathic intracranial hypertension.[18] [19]

AAZ is a low nanomolar inhibitor of carbonic anhydrase isoforms that are involved in the secretion of CSF. Inhibition of the carbonic anhydrase isozymes II, IV, VA, and XII in the brain and choroid plexus results in a reduction in CSF fluid secretion and the maintenance of intracranial pressure. Despite the long-standing clinical use of numerous sulfonamide/sulfamate carbonic anhydrase inhibitors, it appears that only AAZ is currently employed in clinical practice for the treatment of ICH.[18] [19]

Spontaneous fistulas and late installation after trauma or general surgery require immediate surgery, due to the high recidivist rate.[20] [21] Nevertheless, In the absence of a standard approach to the management of spontaneous cerebrospinal fluid (CSF) leaks, the optimal course of action remains undetermined.[12]

Treatment decisions are made on a case-by-case basis, with consideration of several factors. These include obesity (body mass index [BMI] > 30), the velocity of cerebrospinal fluid (CSF) leakage, the magnitude of the skull base defect (>2 cm), a previous history of CSF leaks, and the intricacy of the surgical repair. In light of these considerations, the recommended course of action may entail lumbar drainage, cerebrospinal fluid diversion, or the administration of medications to reduce intracranial pressure.[12]

Several techniques have been described for the treatment of cerebrospinal fluid rhinorrhea. The initial technique was first described by Dandy (1926), who utilized a muscle and fascia lata graft to repair a dural lesion following a frontal fracture trauma. Subsequently, Wigand and Hosemamm (1985) devised an alternative technique utilizing solely the endoscopic approach for the closure of these fistulas, employing mucoperiosteal flaps. Levine's preferred method involves the use of pediculated flaps of the middle turbinate to close the defects in the cribriform plate, effectively preventing the escape of cerebrospinal fluid.[21]

Several types of graft are used and described in the literature for this kind of correction, using conjunctive tissue grafts, such as fascia lata, temporal fascia, and muscle. Furthermore, Herrera Caicedo addresses the use of septal cartilage, positioning it between the dura mater and the previous skull base, underneath the defect, and it has been demonstrated as a highly effective approach, especially in the more extensive defects of the previous skull base.[22] [23]

The contemporary surgical treatment for fistulas adheres to the methodology initially proposed by Dandy. Nevertheless, the efficacy of this approach remains suboptimal. Consequently, there is a need to develop a more efficacious method for the repair of dura mater defects, frequently employing dural implants and biological or synthetic sealants.[21]

In recent years, endoscopic surgery has become the technique of choice for the correction of CSF leaks. Its less invasive nature, lower morbidity and mortality, better visualization during the procedure, and higher success rate, with approximately a 90% success rate in the first procedure, make it a safer method for surgical repair.[24] Other common approaches, such as transcranial and extracranial procedures, have a 70% success rate, as well as possible significant morbidities such as permanent anosmia.[15]

The "underlay" and "onlay" techniques are the most used. These techniques are also used in combination to treat CSF leaks if there is a risk of neurological damage, with the “onlay” being performed in repairs.[25]

Regarding CSF leak complications, the literature indicates that meningeal infections are more prevalent among these patients. However, the incidence of these complications is quite variable, and the relationship between their occurrence and the underlying etiology is not particularly well-defined.[16] Another significant complication associated with this is occurrence of pneumocephalus, which presents in the anterior portion of the skull base. This phenomenon is brought about by contact between the nasal cavity and the intracranial cavity, which may result in headaches and alterations in the level of consciousness.[8]

 

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Conclusion

Based on what was presented in this article, the endoscopic surgical repair approach proved to be satisfactory, with 2 recurrences out of 15 cases analyzed (86% success rate in the first surgical intervention). This result is in line with the literature, which reports a similar rate (approximately 90%).

About the prevalence, there was a statistically significant difference between males, occurring majorly in female patients. As for the choice of techniques, it was not possible to assess a clear relationship between the success of the repair and the choice of endoscopic procedure used. The choice of Onlay or Underlay technique depends on the size of the fistula to be repaired, and both have similar results when applied properly.

 

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Conflict of Interest

The authors declare no conflict of interest or financial assistance.

Acknowledgments

All authors contributed to the study's conception and design. Material preparation, data collection, and analysis were performed by Matheus Felipe Henriques Brandão, Maurus Marques de Almeida Holanda, and Marcos Alexandre da Franca Pereira. The first draft of the manuscript was written by Matheus Felipe Henriques Brandão, Samuel Navarro Freitas, and Rodrigo Franca. The paper was reviewed by Marcos Alexandre da Franca Pereira and Maurus Marques de Almeida Holanda. Surgery was performed by Marcos Alexandre da Franca Pereira, Maurus Marques de Almeida Holanda and Rodrigo Marmo da Costa e Souza. All authors read and approved of the final manuscript.

• Referências

• 1 Prosser JD, Vender JR, Solares CA. Traumatic cerebrospinal fluid leaks. Otolaryngol Clin North Am 2011; 44 (04) 857-873 , vii
• 2 Gupta AK, Gupta AK, Verma M. Cranionasal fistula in pediatric population: is endonasal endoscopic approach effective?. Int J Pediatr Otorhinolaryngol 2007; 71 (10) 1537-1541
• 3 Tahir MZ, Khan MB, Bashir MU, Akhtar S, Bari E. Cerebrospinal fluid rhinorrhea: An institutional perspective from Pakistan. Surg Neurol Int 2011; 2 (01) 174
• 4 Das PT, Balasubramanian D. Extradural cartilage inlay graft in cerebrospinal fluid fistula repair. J Laryngol Rhinol Otol 2010; 124 (12) 1294-1297
• 5 Pilger AD, Schneider LE, Da Silva GM, Schneider KCC, Smidt R. Membranas e barreiras para regeneração óssea guiada. Rev Ciênc Méd Biol 2020; 19 (03) 441-448
• 6 Wax MK, Ramadan HH, Ortiz O, Wetmore SJ. Contemporary management of cerebrospinal fluid rhinorrhea. Otolaryngol Head Neck Surg 1997; 116 (04) 442-449
• 7 Araujo Filho BC, Butugan O, Pádua FG, Voegels RL. Endoscopic repair of CSF rhinorrhea: experience of 44 cases. Braz J Otorhinolaryngol 2005; 71 (04) 472-476
• 8 Bhalodiya NH, Joseph ST. Cerebrospinal fluid rhinorrhea: endoscopic repair based on a combined diagnostic approach. Indian J Otolaryngol Head Neck Surg 2009; 61 (02) 120-126
• 9 Kutz Jr JW, Tolisano AM. Diagnosis and management of spontaneous cerebrospinal fluid fistula and encephaloceles. Curr Opin Otolaryngol Head Neck Surg 2019; 27 (05) 369-375
• 10 Abuabara A. Cerebrospinal fluid rhinorrhoea: diagnosis and management. Med Oral Patol Oral Cir Bucal 2007; 12 (05) E397-E400
• 11 Lobo BC, Baumanis MM, Nelson RF. Surgical repair of spontaneous cerebrospinal fluid (CSF) leaks: A systematic review. Laryngoscope Investig Otolaryngol 2017; 2 (05) 215-224
• 12 Zhu Z, Cheng L, Yang J. Etiology and treatment strategy of spontaneous cerebrospinal fluid rhinorrhea. Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2020;34
• 13 Worrall DM, Pai A, Garneau JC. et al. Temporal Bone Encephaloceles: Utility of Preoperative Imaging. Otolaryngology - Head and Neck Surgery 2020; 163 (03) 577-581
• 14 Mostafa BE, Khafagi A. Combined HRCT and MRI in the detection of CSF rhinorrhea. Skull Base 2004; 14 (03) 157-162 , discussion 162
• 15 Martín-Martín C, Martínez-Capoccioni G, Serramito-García R, Espinosa-Restrepo F. Surgical challenge: endoscopic repair of cerebrospinal fluid leak. BMC Res Notes 2012; 5: 459
• 16 Giannetti AV, Paula A, Silva DM, Fernando P, Borges T. Fístula liquórica da base anterior do crânio: classificação, clínica e diagnóstico. J Bras Neurocir 2011;22(1):
• 17 Daudia A, Biswas D, Jones NS. Risk of meningitis with cerebrospinal fluid rhinorrhea. Ann Otol Rhinol Laryngol 2007; 116 (12) 902-905
• 18 Supuran CT. Acetazolamide for the treatment of idiopathic intracranial hypertension. Expert Rev Neurother 2015; 15 (08) 851-856
• 19 Wall M, McDermott MP, Kieburtz KD. et al; NORDIC Idiopathic Intracranial Hypertension Study Group Writing Committee. Effect of acetazolamide on visual function in patients with idiopathic intracranial hypertension and mild visual loss: the idiopathic intracranial hypertension treatment trial. JAMA 2014; 311 (16) 1641-1651
• 20 Elrahman HA, Malinvaud D, Bonfils NA, Daoud R, Mimoun M, Bonfils P. Endoscopic management of idiopathic spontaneous skull base fistula through the clivus. Arch Otolaryngol Head Neck Surg 2009; 135 (03) 311-315
• 21 Banks CA, Palmer JN, Chiu AG, O'Malley Jr BW, Woodworth BA, Kennedy DW. Endoscopic closure of CSF rhinorrhea: 193 cases over 21 years. Otolaryngol Head Neck Surg 2009; 140 (06) 826-833
• 22 Cassano M, Felippu A. Endoscopic treatment of cerebrospinal fluid leaks with the use of lower turbinate grafts: a retrospective review of 125 cases. Rhinology 2009; 47 (04) 362-368
• 23 Cukurova I, Cetinkaya EA, Aslan IB, Ozkul D. Endonasal endoscopic repair of ethmoid roof cerebrospinal fluid fistula by suturing the dura. Acta Neurochir (Wien) 2008; 150 (09) 897-900 , discussion 900
• 24 Daele JJM, Goffart Y, Machiels S. Traumatic, Iatrogenic, and Spontaneous Cerebrospinal Fluid (CSF) leak: Endoscopic repair. B-ENT 2011; 7 (Suppl. 17) 47-60
• 25 Majhi S, Sharma A. Outcome of Endoscopic Cerebrospinal Fluid Rhinorrhoea Repair: An Institutional Study. Indian J Otolaryngol Head Neck Surg 2019; 71 (01) 76-80

Publication History

Received: 07 May 2024

Accepted: 20 March 2025

Article published online:
16 July 2025