Inclusion Criteria:

Preoperative Inclusion Criteria:

• Subjects undergoing elective craniotomy / craniectomy for pathological processes in the posterior fossa (such as benign and malignant tumors, vascular malformations, and Chiari 1 malformations) that result in dura defects requiring dura substitution for closure and who are able and willing to comply with the procedures required by the protocol
• Signed and dated written informed consent from the subject or from his/her legal representative prior to any study-related procedures
• Age >= 3 years, either gender

Intraoperative Inclusion Criteria:

• Surgical Wound Classification Class I, RIC <= 2. Penetration of mastoid air cells during partial mastoidectomy is permitted.
• A patch of autologous fascia or pericranium or suturable collagen-based dura substitute was cut to size and then sutured into the dura defect.
• The cuff of native dura along the craniotomy edge is >= 10 mm wide, to facilitate suturing and to allow for sufficient surface area for adherence of the investigational product.

Exclusion Criteria:

Preoperative Exclusion Criteria:

• Female subjects who are breastfeeding, pregnant, or intend to become pregnant during the clinical study period
• Subjects with a dura lesion from a recent surgery that still has the potential for CSF leakage
• Chemotherapy scheduled within 7 days following surgery
• Radiation therapy to the head scheduled within 7 days following surgery
• Long-term low-dose steroid therapy to be resumed within 7 days following surgery. However, postoperative tapered high-dose steroids are permitted.
• Subjects with severely altered renal (serum creatinine > 2 mg/dL) and/or hepatic function [ALT, AST > 5 x upper limit of norm (ULN)
• Evidence of an infection indicated by any one of the following: fever > 101°F, WBC < 3500/μL or > 13000/μL, positive urine culture, positive blood culture, positive chest X-ray. Evidence of infection along the planned surgical path. A WBC count of < 20000 is permitted if the patient is being treated with steroids in the absence of all the other infection parameters.
• Conditions compromising the immune system; existence of autoimmune disease
• Known hypersensitivity to aprotinin or other components of the investigational product
• Non-compliant or insufficient treatment of diabetes mellitus [glycosylated hemoglobin (HbA1c) > 7.5%]
• Hydrocephalus, except occlusive hydrocephalus caused by posterior fossa pathology to be treated
• Existing CSF (ventricular, etc.) drains. Burr holes are permitted as long as the dura remains intact. Cushing cannulation excludes the subject.
• Female subjects of childbearing potential with a positive urine or serum pregnancy test within 24 hours prior to surgery
• Participation in another clinical trial with exposure to another investigational drug or device within 30 days prior to enrollment
• Scheduled or foreseeable surgery within the follow-up period

Intraoperative Exclusion Criteria:

• Dura injury during craniotomy / craniectomy that cannot be eliminated by widening the craniotomy/craniectomy to recreate the native dura cuff
• Failure to administer preoperative antibiotic prophylaxis
• Use of implants made of synthetic materials coming into direct contact with dura (e.g., PTFE patches, shunts, ventricular and subdural drains)
• Placement of Gliadel wafers
• Chiari 1 subjects without injury to the arachnoid
• Persistent signs of increased brain turgor
• Use of product(s) other than FS VH S/D 500 s-apr for the sealing of dura sutures, including packing with Gelfoam
• Brain surface visible between suture loops as a manifestation of increased suture tension
• Intersecting durotomy scars in the surgical path from a previous operation that cannot be completely removed by the planned dura resection
• Two or more separate dura defects
• Major intraoperative complications that require resuscitation or deviation from the planned surgical procedure