Evaluation of Non-Watertight Dural Reconstruction with Collagen Matrix Onlay Graft in Posterior Fossa Surgery

OBJECTIVE: Many surgeons advocate for watertight dural reconstruction after posterior fossa surgery given the significant risk of cerebrospinal fluid (CSF) leak. Little evidence exists for posterior fossa dural reconstruction utilizing monolayer collagen matrix onlay graft in a non-watertight fashion. Our objective was to report the results of using collagen matrix in a non-watertight fashion for posterior fossa dural reconstruction. METHODS: We conducted a retrospective review of operations performed by the senior author from 2004-2011 identified collagen matrix (DuraGen) use in 84 posterior fossa operations. Wound complications such as CSF leak, infection, pseudomeningocele, and aseptic meningitis were noted. Fisher's exact test was performed to assess risk factor association with specific complications. RESULTS: Incisional CSF leak rate was 8.3% and non-incisional CSF leak rate was 3.6%. Incidence of aseptic meningitis was 7.1% and all cases resolved with steroids alone. Incidence of palpable and symptomatic pseudomeningocele in follow-up was 10.7% and 3.6% respectively. Postoperative infection rate was 4.8%. Previous surgery was associated with pseudomeningocele development (p<0.05). CONCLUSION: When primary dural closure after posterior fossa surgery is undesirable or not feasible, non-watertight dural reconstruction with collagen matrix resulted in incisional CSF leak in 8.3%. Incidence of pseudomeningocele, aseptic meningitis, and wound infection were within acceptable range. Data from this study may be used to compare alternative methods of dural reconstruction in posterior fossa surgery.

Pre -vs. Post-Anterior Clinoidectomy Measurements of the Optic Nerve, Internal Carotid Artery, and Optico-Carotid Triangle: A Cadaveric Morphometric Study

Anterior clinoid process is a small bony structure but it is very important regarding its location and relationships with neighboring neurovascular, dural, and bony structures. Removal of this process has been used in various modification of standard pterional approach. The authors have speculated how much expansion of operative window could be obtained with anterior clinoidectomy, so we measured the lengths of optic nerve, internal carotid artery, and the length and width of optico-carotid triangle(OCT) before and after extradural anterior clinoidectomy 17 times in 10 cadaveric heads. This procedure provided about two fold increase in the length of optic nerve and OCT, and over three fold expansion in the width of OCT. The results indicate that the addition of this relatively simple and easy procedure to standard approach makes the operative field more comfortable and safe than expected. We believe this procedure can be used routinely with or without combination of wide skull base exposure in cases of such lesions as belows: 1) lesions causing optic nerve or chiasmatic compression, 2) lesions encircling/covering the optic nerve and internal carotid artery, 3) lesions arising from or extending into the optic canal, orbital apex, and paraclinoid region, 4) suprasellar/parasellar lesions with limited operative windows(e.g. prefixed chiasm, infra-optic or subchiasmatic locations or adherence).