Dural Repair After Craniotomy and the Use of Dural Substitutes and Dural Sealants

Delayed hypersensitivity reaction to a dural repair substitute

BACKGROUND

Modern neurosurgeons commonly rely on dural grafts to aid in obtaining watertight closures when the native dura itself cannot be approximated.

CASE PRESENTATION

We present a patient who developed a symptomatic, delayed hypersensitivity reaction to a cellulose-based synthetic dural graft, which resolved after reoperation and removal of the graft.

DISCUSSION

Dural grafts are a safe and common implant utilized in neurosurgery. Nevertheless, as with all implanted material, there is a chance for symptomatic immune reactions to occur.

CONCLUSION

This type of response is exceedingly uncommon, but recognition of this rare presentation may help other providers recognize it in the future.

Improved Swelling Property of Tissue Adhesive Hydrogels Based on α-Cyclodextrin/Decyl Group-Modified Alaska Pollock Gelatin Inclusion Complexes

Adhesives/sealants are used after suturing to prevent leakage of cerebrospinal fluid from an anastomotic site. Commercial adhesives/sealants have been used to close the cerebral dura. However, swelling of the cured adhesives/sealants induces increased intracranial pressure and decreases the strength of the seal. In the present study, tissue adhesive hydrogels with improved swelling property using inclusion complex composed of α-cyclodextrin (αCD) and decyl group (C10)-modified Alaska pollock-derived gelatin (C10-ApGltn) with a high degree of substitution (DS) (>20 mol%) are developed. Viscosity of C10-ApGltn with a high DS solution remarkably decreased by the addition of αCD. The resulting αCD/C10-ApGltn adhesive hydrogel composed of αCD/C10-ApGltn inclusion complexes and poly(ethylene glycol) (PEG)-based crosslinker showed improved swelling property after immersion in saline. Also, the resulting adhesive has a significantly higher burst strength than fibrin-based adhesives and is as strong as a PEG-based adhesive. Quantitative analysis of αCD revealed that the improved swelling property of the resulting adhesive hydrogels is induced by the release of αCD from cured adhesive, and the subsequent assembly of decyl groups in the saline. These results suggest that adhesives developed using the αCD/C10-ApGltn inclusion complex can be useful for closing the cerebral dura mater.

Ex vivo evaluation of a multilayered sealant patch for watertight dural closure: cranial and spinal models

Cerebrospinal fluid leakage is a frequent complication after cranial and spinal surgery. To prevent this complication and seal the dura watertight, we developed Liqoseal, a dural sealant patch comprising a watertight polyesterurethane layer and an adhesive layer consisting of poly(DL-lactide-co-ε-caprolactone) copolymer and multiarmed N-hydroxylsuccinimide functionalized polyethylene glycol. We compared acute burst pressure and resistance to physiological conditions for 72 h of Liqoseal, Adherus, Duraseal, Tachosil, and Tisseel using computer-assisted models and fresh porcine dura. The mean acute burst pressure of Liqoseal in the cranial model (145 ± 39 mmHg) was higher than that of Adherus (87 ± 47 mmHg), Duraseal (51 ± 42 mmHg) and Tachosil (71 ± 16 mmHg). Under physiological conditions, cranial model resistance test results showed that 2 of 3 Liqoseal sealants maintained dural attachment during 72 hours as opposed to 3 of 3 for Adherus and Duraseal and 0 of 3 for Tachosil. The mean burst pressure of Liqoseal in the spinal model (233 ± 81 mmHg) was higher than that of Tachosil (123 ± 63 mmHg) and Tisseel (23 ± 16 mmHg). Under physiological conditions, spinal model resistance test results showed that 2 of 3 Liqoseal sealants maintained dural attachment for 72 hours as opposed to 3 of 3 for Adherus and 0 of 3 for Duraseal and Tachosil. This novel study showed that Liqoseal is capable of achieving a strong watertight seal over a dural defect in ex vivo models.

Autologous Temporalis Subfascial Fat Graft for Skull Base Repair: A Novel Technique

BACKGROUND

Autologous abdominal fat grafts are occasionally used in the repair of skull base exposures. This surgical procedure typically requires an additional surgical site and may have unexpected postoperative complications.

OBJECTIVE

To describe an operative technique for harvesting subfascial fat from the temporal extension of the buccal fat pad for the repair of skull base defects.

METHODS

We review the pertinent anatomy of the temporalis subfascial fat pad and discuss the technique used to harvest the subfascial fat component in a clinical presentation.

RESULTS

A pretemporal approach was performed for clip ligation of an anterior circulation aneurysm. A standard frontotemporal incision was made with an interfascial flap to preserve the frontalis branches of the facial nerve. The subfascial fat was inspected and determined to be adequate for harvesting. Monopolar cauterization was carefully utilized to remove the fat. During closure, the graft was used to repair a pneumatized clinoid sinus and for the dural repair of the pretemporal exposure. The patient did not have any postoperative complications.

CONCLUSION

Autologous temporalis subfascial fat graft is a viable and safe technique for skull base dural and sinus repair during frontotemporal approaches in select patients. This technique avoids an additional surgical procedure and potential complications that may be associated with it.

Homologous amniotic membrane as a dural substitute in decompressive craniectomies

INTRODUCTION

A dura mater substitute in decompressive craniectomies must protect the brain while providing a dissection plane between the cortex and myocutaneous layer. The human amniotic membrane (AM) has anti-inflammatory, wound healing, and differentiation properties. We tested AM properties as a dural substitute by comparing the outcomes to biological ones.

METHODS

We prospectively collected data on 25 patients who randomly underwent decompressive craniectomy with lyophilized AM patches and 25 in which biological substitutes were utilized between 2015 and 2019. The AM was laid with the epithelial side facing the brain because of the anti-adhesive proprieties, while the chorion facing the myocutaneous flap. We collected data on demographics, neurological status, comorbidities, and surgical outcomes. Additionally, we created a score - dura mimicking score- and reviewed postoperative imaging and pathological specimens.

RESULTS

The majority (96%) of AM grafts were integrated into native dura. Thirteen patients scored as excellent and 11 good on our "dura mimicking score", showing tissue integration ability but no cerebral cortex adhesion. The histopathological analysis showed that AM had thick plates of dense fibrous tissue with small reactive vessels, reactive fibroblasts, and lymphocytes infiltrate. The AM group's first outcomes were not different from the biological substitute patients but higher integration rate to the dura and less adhesion to the myocutaneous flap in AM patients.

CONCLUSIONS

We documented the anti-adhesive, protective, and integrative properties of AM dural substitute patches in patients who underwent decompressive craniectomies, comparing the intraoperative differences and postoperative outcomes to biological dural substitutes.

Treatment of CSF leakage and infections of dural substitute in decompressive craniectomy using fascia lata implants and related anatomopathological findings

PURPOSE

Decompressive craniectomy (DC) is widely used to treat raised intracranial pressure (ICP) in cranial trauma and stroke. It is accompanied by numerous complications. The aim of our study is to assess the surgical treatment of infections related to the use of a dural substitute with concurrent CSF leakage performed at our institution.

MATERIAL AND METHODS

A retrospective analysis of a series of 72 patients who underwent DC between 2011 and 2017 was performed. Seven cases (9%) showed infection related to the use of xenograft (bovine pericardium) and coexisting CSF leakage. Epidural/subdural empyemas were observed in seven cases; three in conjunction with an intracerebral abscess. For reconstruction, free anterolateral thigh fascia lata flaps were used, based on the size of the defect.

RESULTS

After removal of the dural substitute and the implant of free fascia lata, infection and CSF leaks resolved in all. An anatomopathological examination of the implant at the later time of cranioplasty (CP) showed the tissue had become vascularized exhibiting integration with the native dura. No complications related to the harvesting of the fascia lata were observed.

CONCLUSIONS

Fascia lata is a validated source of autologous grafts; it is cost-free and would appear to be the biological material most similar to the dura mater. The implanted material appears to maintain a lasting vitality when covered over with a well-vascularized scalp, even after a period of months, achieving a successful suppression of infection. Subsequent skull reconstruction is performed safely and easily using artificial bone.

Comparison of dural closure alternatives: an experimental study

Introduction: Dural closure preference has been a topic of debate in contemporary neurosurgery. This study aims to compare different closure techniques using an in vitro model.Methods: Human cadaveric dura mater was attached to a cylindrical metal glass filled with blue dyed saline. A 1 cm dural incision was made. Dural closure was performed using three different techniques. Each group had six samples: Group I - interrupted simple 4-0 polyglactin suture (S) only, Group II - S plus on lay collagen graft, Group III - S plus fibrin sealant. In Group NS, a 1 cm × 1 cm dural window was made. An onlay collagen graft was used with no suturing for this group to serve as an overtly weak reconstruction reference. Primary and secondary leak pressures were recorded (PLP and SLP, respectively).Results: All groups (I-III) had significantly higher PLP and SLP than Group NS. PLP was significantly higher in Group III as compared to groups I and II. Groups I and II had similar PLP values. SLP was similar in all three groups.Conclusion: In this study, the use of fibrin sealant has proven to be the best option in preventing dural leak. However, no technique was superior in the case of SLP.

Safety and Efficacy of a Novel, Self-Adhering Dural Substitute in a Canine Supratentorial Durotomy Model

BACKGROUND

Cerebrospinal fluid (CSF) leaks increase postoperative risk for complication, likelihood of reoperation, and costs.

OBJECTIVE

To investigate a novel, self-adhering polyethylene glycol-coated collagen pad (PCC) as a dural substitute relative to Duragen XS (DGX; Integra LifeSciences Corporation, Plainsboro, New Jersey) and as a dural sealant relative to Tachosil (Takeda Austria GmbH, Linz, Austria), a fibrinogen and thrombin-coated collagen pad (FTC).

METHODS

A canine supratentorial durotomy surgical model was used to investigate the safety and efficacy of PCC. For safety, 4 animals were bilaterally treated with DGX or PCC and recovered for 1, 8, or 16 wk; total 24 animals. Each animal underwent physical and neurological examinations weekly and 16-wk animals underwent a magnetic resonance imaging (MRI) examination at each time point. For efficacy, 9 animals were unilaterally treated with FTC or PCC and underwent a burst pressure test intraoperatively or 14 d postoperatively; total 36 animals.

RESULTS

In the safety study, no abnormal clinical signs or changes were noted on physical and neurological examinations, or in clinical pathology, CSF analysis or histopathology of DGX or PCC-treated animals. No consistent signs of cerebral compression, CSF leak, hemorrhage, or hydrocephalus were noted on MRI. In the efficacy study, no significant difference was found between FTC and PCC at each time point or overall (13.9 vs 12.3 mm Hg, n = 18 per group, P = .46).

CONCLUSION

PCC is safe for use as a dural substitute and effective as a dural sealant. The novel, self-adhering combination of a polyethylene glycol-based sealant and a collagen pad may offer unique benefits to the advancement of duraplasty.

Skull Base Dural Repair Using Autologous Fat as a Dural Substitute: An Efficient Technique

BACKGROUND

Dural repair during skull base approaches remains challenging, especially in the presence of significant defects. The autologous fat has become an alternative to various substitute materials being used previously. We report here our experience and technique for the repair of notable skull base dural defects using autologous fat as a dural substitute.

METHODS

Over a period of 5 years, 71 consecutive patients operated on for skull base pathologies with an important intraoperative dural defect repaired using autologous fat tissue as replacement material were reviewed. The graft, withdrawn from the abdomen or thigh, was flattened and applied to the defect. The clinical findings and outcomes were assessed.

RESULTS

Main pathologies included schwannomas (45%) and meningiomas (35.21%), with no side predilection. Surgical approaches such as transcondylar fossa, suboccipital, and frontotemporal approaches were used. Dural defects were mainly located in the posterior (73.2%) and middle cranial fossae (25.4%). No harvesting site-related complication occurred. In 7 cases, transitory subcutaneous fluid collection spontaneously resorbing after 8 days to 2 months was observed. No external cerebrospinal fluid leakage, infection, or other complication was noted during the following period.

CONCLUSIONS

Dural repair can be effectively and durably achieved using autologous fat graft as a dural substitute during skull base approaches, even in cases of extended defects. The observed characteristics of the fat graft along with the achieved outcome make it an ideal dural substitute.

Natural Sources of Extracellular Matrix for Cardiac Repair

Tissue engineering and regenerative medicine have adopted the use of extracellular matrix (ECM) as a cell delivery device and bioactive regenerative agent. To this end, many ECMs have been investigated for cardiac tissue engineering and regenerative medicine applications with variable success. Many sources of natural ECMs have been tested for cardiac applications. Typically, natural ECMs have been made from decellularized organs or tissues and processed into either sheets or injectable hydrogels. This chapter will review natural sources of ECM materials that have been tested as therapeutic agents in models of heart failure.

Rationale Behind the Use of Double-Layer Polypropylene Patch (G-patch) Dural Substitute During Decompressive Craniectomy as an Adhesion Preventive Material for Subsequent Cranioplasty with Special Reference to Flap Elevation Time

OBJECTIVE

Dural substitutes are used in decompressive craniectomy (DC) to prevent adhesions during subsequent cranioplasty. Current literature attributes them to reduced blood loss and reduction in operative time of cranioplasty. The use of double-layer substitute has rarely been documented. We studied the use of double-layer G-patch as a dural substitute in DC and evaluated its outcome during subsequent cranioplasty with special focus on flap elevation time and blood loss during cranioplasty.

METHODS

We performed emergency frontotemporoparietal decompressive craniectomy using a 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 were recorded.

RESULTS

During the cranioplasty, a clear and smooth plane of dissection was found between the 2 layers of G-patch in all 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.

CONCLUSIONS

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 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.

Dural repair using autologous fat: Our experience and review of the literature

Background:

Various materials have been proposed to obliterate dead spaces and to reconstruct dural defects during a neurosurgical approach. This study describes our technique of using the abdominal autologous fat graft and evaluates the complications and characteristics related to the use of this tissue during cranial procedures.

Methods:

Autologous fat grafts were used in 296 patients with basicranial and convexity extraaxial tumors from April 2005 to January 2015. The adipose tissue was removed from the paraumbilical abdominal region and was transformed into a thin foil. When possible, a watertight suture was made between the dural or bone edge with a fat graft. We always used fibrin glue to reinforce the dural closure.

Results:

Complications occurred between 2 days and 1 year following procedure. Cerebrospinal fluid leaks were found in 11 cases. No case of mortality, pseudomeningoceles, fistula, infections, bacterial meningitides, or lipoid meningitides was reported. No patient required removal of the graft. No adhesion was observed between the brain and the autologous fat. Other fat-related complications observed were 2 cases of fat necrosis in the abdomen and 2 cases of abdominal hemorrhage.

Conclusion:

The technique of harvesting and applying fat grafts is fairly simple, although it must be performed meticulously to be effective. Our experience has led us to believe that the use of fat grafts presents low morbidity and mortality. However, a neurosurgeon should never forget the possible late or early complications related to the use of fat grafts.

Bilayer oxidized regenerated cellulose/poly ε-caprolactone knitted fabric-reinforced composite for use as an artificial dural substitute

A novel bilayer knitted fabric-reinforced composite for potentially being used as a dural substitute was developed by solution infiltration of oxidized regenerated cellulose knitted fabric (ORC) with poly ε-caprolactone (PCL) solution at various concentrations ranging 10-40 g/100 mL. It was found that the density of all formulations did not differ significantly and was lower than that of the human dura. Microstructure of the samples typically comprised a bilayer structure having a nonporous PCL layer on one side and the ORC/PCL composite layer on another side. Tensile modulus and strength of the samples initially decreased with increasing PCL solution concentration for up to 20 g/100 mL and re-increased again with further increasing PCL solution concentration. Strain at break of all formulations were not significantly different. Watertight test revealed that all composites could prevent leakage at the pressure within the normal range of intracranial pressure. In vitro degradation study revealed that the weight loss percentage and change in tensile properties of all samples displayed biphasic profile comprising an initially rapid decrease and followed by a gradual decrease with incubation times afterward. Micro and macro porous channels were observed to be in situ generated in the composite layer by ORC dissolution and PCL resorption during degradation while nonporous layer remained relatively unchanged. The degradation rate was found to decrease with increasing PCL solution concentration. In vitro biocompatibility using alamar blue assay on selected samples showed that fibroblasts could attach and proliferate well at all incubation periods.