Minimally Invasive Endoscopic Repair of Refractory Lateral Skull Base Cerebral Spinal Fluid Leaks: A Summary and Technical Synthesis

Cerebrospinal fluid (CSF) leaks occur in 10% of patients undergoing a translabyrinthine approach, 15% a retrosigmoid craniotomy, and 13% a middle fossa approach for vestibular schwannoma resection. CSF rhinorrhea also results from trauma and congenital defects. A high degree of difficulty in repair sometimes requires repetitive microsurgical revisions; 10% of cases are often cited. Not only does this cause lingering symptoms for patients but also is costly and burdensome for the health care system; a median value of $50,401.25 for standard repair approaches. In this case-based analysis, we discuss CSF leaks with traditional approaches, and describe the endoscopic endonasal techniques used to obliterate the eustachian tube: summarized in. Cost comparison estimates of endoscopic endonasal versus open approaches for repair are compared (Table 2). Based on our analysis, the endoscopic endonasal approach to obliterate the eustachian tube should be considered as a first- or second-line technique for repair of refractory CSF rhinorrhea.

We report a summary of articles in which the median cost of microsurgical techniques for repair of lateral skull base CSF leaks was performed (Table 2). We compared the median reported cost of endoscopic endonasal CSF leak repair to the median microsurgical techniques. We summarized the studies that reported endoscopic endonasal eustachian tube obliteration (EEETO), the specific technique used, and the outcomes (Table 1). Our case experience is illustrated to demonstrate the EEETO technique.

The estimated median cost differential between microsurgical repair for refractory CSF leak and endoscopic endonasal repair techniques is significant, $50,401.25 versus $11,438, respectively. The summary of EEETO articles demonstrates that this minimally invasive low morbidity procedure has shown success empirically for the treatment of refractory CSF rhinorrhea from a lateral skull base source. Our case illustration suggests that cauterization, packing with muscle, partial inferior turbinectomy, and cerclage of the eustachian tube nasopharyngeal orifice via an EEETO approach was successful at more than 8 months follow-up. The EEETO was successful when CSF diversions, wound re-exploration, revised packing of the eustachian tube from a lateral microscopic translabarynthine approach, and use of a vascularized flap failed.

In selected cases, EEETO may be the technique most likely to lead to success in treatment of refractory CSF rhinorrhea from a lateral skull base source. Endoscopic repair procedures possess a median cost of $11,438, much less than most standard microsurgical repair procedures. The potential for cost-savings is substantial. Additionally, the technique is less invasive with potential for an excellent outcome. EEETO could be readily implemented into algorithms once lumbar drains have failed for refractory CSF rhinorrhea, prior to considering open surgery. Future studies are warranted to further demonstrate the outcome and cost-saving benefits of the EEETO, as the data until now are only empiric but very hopeful. Synthesis of the EEETO articles afforded our group a basis on which to guide our ultimately successful treatment. The summaries and technical notes this article describes may serve as a resource for those skull base teams faced with similar challenging and otherwise refractory CSF leaks.