What is the surgical repair for a Central Nervous System (CNS) leak after an endoscopic endonasal transsphenoidal surgery called?

Surgical Repair for CNS Leak After Endoscopic Endonasal Transsphenoidal Surgery

The surgical repair for a cerebrospinal fluid (CSF) leak following endoscopic endonasal transsphenoidal surgery is called a multilayer skull base reconstruction or sellar floor reconstruction. 1, 2

Diagnosis and Localization of CSF Leak

• CSF leak after transsphenoidal surgery is confirmed by β2-transferrin or β2-trace analysis of the fluid 1
• High-resolution CT (HRCT) is the first-line imaging study for localizing the skull base defect, with a reported sensitivity of 88-95% 1
• MRI with heavily T2-weighted sequences (MR cisternography) may be used in conjunction with HRCT for improved localization, with a combined sensitivity of 90-96% 1
• CT cisternography is primarily used when multiple osseous defects are identified on HRCT to determine the specific leak site 1

Surgical Repair Techniques

Multilayer Closure Methods

• Primary closure of the dural defect is the most desirable solution for intraoperatively encountered CSF leaks 3
• Multilayer closure using acellular dermis is an effective method for surgical repair of the fistula site 2
• For higher-grade CSF leaks, a combination of techniques is typically employed:
  • Grade 1 (small) leaks: Buttress placement significantly decreases postoperative leakage 4
  • Grade 2-3 (larger) leaks: Both fat grafting and buttress placement are required to significantly reduce postoperative CSF leakage 4

Specific Reconstruction Materials and Techniques

• Autologous fat grafts harvested from the abdomen are commonly used to fill the dead space of the sellar resection cavity 5, 4
• Synthetic dural substitutes may be used as an alternative to autologous tissue 4
• Non-penetrating titanium clips (AnastoClip Vessel Closure System) can be used for primary closure of the fistula 3
• Vascularized nasoseptal flaps significantly decrease the rate of postoperative CSF leaks 6
• Buttress materials (such as bone, cartilage, or synthetic materials) are wedged into the sellar defect site to provide support for the repair 4

Risk Factors and Prevention

• Intraoperative CSF leak is a significant predictor of postoperative CSF leak (OR 4.56) 6
• Resection of tumors causing Cushing's disease is associated with increased risk of postoperative CSF leak (OR 5.79) 6
• Increasing surgical experience is strongly associated with decreased risk of postoperative CSF leak (OR 0.14) 6
• Preventive sellar floor reconstruction in cases with extensive arachnoid herniation, even without visible CSF leak, can be beneficial 5

Clinical Considerations

• Persistent CSF leaks require surgical treatment due to the risk of serious complications including meningitis, brain abscess, and pneumocephalus 1, 2
• The size, number, and cause of the CSF fistula generally do not affect surgical outcomes, but the presence of hydrocephalus is a significant negative variable 2
• Metal artifacts from titanium clips on postoperative imaging are generally tolerable and do not significantly interfere with follow-up 3

Accurate identification of intraoperative CSF leaks and appropriate multilayer reconstruction techniques are essential for preventing this common complication of transsphenoidal surgery 5, 4.