Since the 1890s, several materials have been used as dural substitutes. At this point, the most commonly used substitutes are autologous grafts, e.g. fascia lata and galea-pericranium, or synthetic meshes. The synthetic meshes can be either absorbable or non-absorbable.
The standard methods of dura mater repair consist of the application of sealants and the use of dura mater replacement materials (duraplasty) to expand or replace the resected dura mater during a neurosurgical procedure.
Dural substitutes are used as patches to prevent CSF leakage and infection and foster regrowth of dura-like tissue across the defect. Native autologous tissue grafts, such as the fascia lata, temporal fascia, and pericranium, can perform well as dural substitutes because they do not provoke severe inflammatory or immunological reactions, but potential drawbacks, such as difficulty in achieving a watertight closure, formation of scar tissue, insufficiently accessible graft materials to close large dural defects, and additional incisions for harvesting the graft, remain problematic.
Off-the-shelf dural substitutes have been developed as alternatives to autologous transplantation and various xenografts have been studied, including bovine and ovine pericardium, porcine small intestinal submucosa, and processed collagen matrices. However, these xenografts are often associated with adverse effects, such as graft dissolution, encapsulation, foreign body reaction, scarring, and adhesion formation. Permanent and bioresorbable synthetic polymer membranes have also been tested as dural substitutes.
Although many efforts have been made, the challenge to develop a suitable dural substitute has been met with limited success.
Several types of dural substitute materials have recently been discarded or modified owing to poor biocompatibility or mechanical properties and adverse reactions.
Numerous natural and synthetic substitutes have been proposed for dural grafting. Autografts, allografts, xenografts and nonabsorbable or absorbable polymer sheets have been used in experimental models and clinical practice 1).
Bovine tissues are now routinely used for dural closure in cranial and spinal surgery.
GORE® PRECLUDE® PDX
Dural substitutes are used in decompressive craniectomy (DC) in order to prevent adhesions during subsequent cranioplasty. Current literature attributes them to the reduced blood loss and reduction in operative time of cranioplasty. The use of double layer substitute has rarely been documented. We decided to study the use of double layer G-patch as a dural substitute in DC and evaluate its outcome during subsequent cranioplasty with special focus on flap elevation time and blood loss during cranioplasty.
MATERIALS AND METHODS: We performed emergency frontotemporoparietal (FTP) decompressive craniectomy using double layer of G-patch as dural substitute. Subsequent cranioplasty was done in these 35 patients. The development of adhesion formation between the tissue layers, amount of blood loss and flap elevation time was recorded.
RESULTS: During the cranioplasty, clear and smooth plane of dissection was found between the two layers of G-patch in all the cases. Average flap elevation time was 21.8 minutes and average time taken for cranioplasty was 124.12 minutes. Average blood loss was 83 ml. None of the patients required re-exploration for infection of bone flap or postoperative bleed.
CONCLUSION: While evaluating the use of dural substitute during DC as an adhesion preventive material for subsequent cranioplasty, flap elevation time and blood loss should be taken into account rather than the operative time. Double layer G-patch during DC facilitates subsequent cranioplasty by preventing adhesions between the layers resulting in easier dissection and reduced blood loss 2).
Raghavan A, Wright JM, Wright C, Sajatovic M, Miller J. Response to Letter to the Editor: Dural Substitutes and presstitutes - the FINAL word. World Neurosurg. 2019 Apr 5. pii: S1878-8750(19)30973-8. doi: 10.1016/j.wneu.2019.03.292. [Epub ahead of print] PubMed PMID: 30959257.