Evaluation of Cranial Flap Fixation With Montage Flowable Settable Bone Paste

Inclusion Criteria: 1. Male or female \> 18 years of age 2. Undergoing a cranial procedure in supratentorial location 3. Width of craniotomy kerf line \<3mm for than 75% of the bone flap border Exclusion Criteria: 1. Subject requires a procedure involving a translabyrinthine, transsphenoidal, transoral approach, or any procedure that penetrates the air sinus or mastoid air cells. 2. Subject has clinically significant hydrocephalus or clinical evidence of altered CSF dynamics. 3. Subject has undergone a previous, open intracranial neurosurgical procedure in the same anatomical location. (Note: stereotactic biopsy was not exclusionary). 4. Subject requires a craniectomy (the bone flap is not replaced during the current surgery). 5. Subject had radiation treatment to the surgical site, or standard fractionated radiation therapy was planned post index-procedure. (Note: stereotactic radiosurgery prior to the planned index procedure was not an exclusion criterion.) 6. Subject requires a craniotomy across the sinus for which Montage Flowable is applied adjacent to or within the sinus to fixate the cranial flap. 7. Subject has a condition with anticipated survival shorter than six months. 8. Subject has undergone chemotherapy treatment, excluding hormonal therapy, within three weeks prior to the planned index procedure, or use of intracavitary chemotherapy wafer (BCNU) was planned, or chemotherapy treatment was planned within two weeks after the index procedure was performed. 9. Standard use of peri-operative steroids (i.e., corticosteroids) is permitted. Chronic steroid use (defined as daily use of corticosteroids for ≥ 8 weeks) for the purposes of reducing the side effects of chemotherapy and/or radiation therapy for cancer is not exclusionary unless the patient is deemed by the investigator to be suffering from steroid toxicity (i.e., Cushing's syndrome) manifested by symptoms and signs such as thin skin, striae, easy bruising, muscle atrophy, upper body obesity, severe fatigue, etc. Use of corticosteroids on a chronic basis (as defined previously) for purposes other than decreasing the symptoms of systemic chemotherapy is exclusionary unless those steroids were discontinued 4 weeks prior to the planned index procedure. 10. Subject receives warfarin, heparin, other anticoagulant agents on a daily basis and pre-surgical, standard of care drug wash-out did not occur. 11. Subject is pregnant, breast-feeding, or intended to become pregnant during the course of the study.