The use of dehydrated amniotic membrane allograft for augmentation of dural closure in craniotomies and endoscopic endonasal transphenoidal surgeries

Human Amniotic Membrane for Dural Repair and Duraplasty: A Systematic Review of Safety and Efficacy

The use of human amniotic membrane (HAM) has recently gained attention as a promising alternative option for duraplasty due to its superior tensile strength, elasticity, and anti-inflammatory and anti-fibrotic properties, offering greater durability and reliability compared to autologous grafts like the muscle fascia and pericranium. This systematic review aimed to evaluate the complications associated with duraplasty using HAM. We comprehensively searched the PubMed, Scopus, and Web of Science databases for studies on duraplasty with HAM. The eligibility criteria included studies on patients who underwent dural repair with duraplasty using HAM, with or without a control group. Duraplasty involves opening the dura mater, the protective covering of the brain and spinal cord, and using a graft to enlarge the space around the cerebellum. Dual repair, on the other hand, involves repairing the dura mater without opening it and then using a patch to enlarge the space around the cerebellum. Randomized controlled trials, observational studies, case series, and case reports were included, and quality assessment was conducted. Our search yielded 191 articles. Ten studies were included, with a total of 560 participants. The overall incidence of cerebrospinal fluid (CSF) leakage was three (0.63%) out of 478 in the HAM group and three (4.76%) out of 63 in the other methods group (pericranium, temporalis fascia, and biological dural substitutes). Regarding the incidence of postoperative complications, the overall incidence was eight (1.92%) out of 417 in the HAM group and two (8%) out of 25 in the other methods group. The overall incidence of meningitis was one (0.67%) out of 150 in the HAM group and three (10%) out of 30 in the other methods group. In conclusion, duraplasty using HAM may be a safe and effective alternative to traditional methods, with a low incidence of CSF leakage and postoperative complications.

A pilot study of the use of human amniotic membrane as subcutaneous implants in a mouse model: a potential for temporary substitutes in two-stage breast reconstructions

INTRODUCTION

Breast reconstruction by prosthesis is frequently performed in breast cancer treatments, and a temporary substitute is used in the first step of two-stage operations.

AIM

Due to the advantageous biological features of the human amniotic membrane, we aimed to evaluate its use for temporary implants.

METHOD

We prepared small spherical implants from human amniotic membranes and inserted them into BALB/c mice's subcutaneous flanks. Then, we compared the bulging they produced, the durability, and the host reaction with implants made from the chorionic membrane, folded membrane patches, and sterile plastic beads.

RESULTS

All amionitic cases were healthy throughout the study and only mild inflammation occurred in them. Furthermore, the bulging of the implants was acceptable and faded gradually. However, moderate inflammation was observed in chorionic implant mice, and the bulging disappeared very soon. Finally, the control group had severe inflammation and the beads implant was rejected.

CONCLUSION

Our study showed that the human amniotic membrane could represent a safe and valid tool for breast reconstruction, however, further studies on larger animals and more implants are suggested.

Application of amniotic membranes in reconstructive surgery of internal organs-A systematic review and meta-analysis

Amniotic membrane (AM) has great potential as a scaffold for tissue regeneration in reconstructive surgery. To date, no systematic review of the literature has been performed for the applications of AM in wound closure of internal organs. Therefore, in this systematic review and meta-analysis, we summarize the literature on the safety and efficacy of AM for the closure of internal organs. A systematic search was performed in MEDLINE-PubMed database and OVID Embase to retrieve human and controlled animal studies on wound closure of internal organs. The Cochrane Risk of Bias tool for randomized clinical trials and the SYRCLE risk of bias tool for animal studies were used. Meta-analyses (MAs) were conducted for controlled animal studies to assess efficacy of closure, mortality and complications in subjects who underwent surgical wound closure in internal organs with the application of AM. Sixty references containing 26 human experiments and 36 animal experiments were included. The MAs of the controlled animal studies showed comparable results with regard to closure, mortality and complications, and suggested improved mechanical strength and lower inflammation scores after AM application when compared to standard surgical closure techniques. This systematic review and MAs demonstrate that the application of AM to promote wound healing of internal organs appears to be safe, efficacious, and feasible.

Human amniotic membrane as a dural substitute in neurosurgery: A systematic review

Background:

Several studies have highlighted the use of human amniotic membrane (HAM) in neurosurgical procedures as an effective dural substitute. HAM has inherent antifibrotic and anti-inflammatory properties and exhibits immunomodulatory effect that makes it an ideal dural substitute. Other advantages including easy availability, low cost of procurement, and storage also render it a promising dural substitute especially in low- and middle-income countries.

Methods:

A systematic literature search was performed using PubMed, Scopus, and Google Scholar databases, using the search terms “human amniotic membrane,” “dural repair,” and “neurosurgery.” To be eligible for inclusion in our review, papers had to report primary data, be published in English language and report dural repair on humans with human amniotic membrane. Eligibility assessment was conducted by two independent reviewers with qualitative analysis on the basis of surgical utility, postoperative complications, and histological analysis.

Results:

Eight articles met the predefined inclusion criteria, including three randomized control trials and five cohort studies. We evaluated the use of HAM grafts in dural repair for elective cranial surgery (four studies), trauma surgery (three studies), and elective spine surgery (one study). Cases with postoperative cerebrospinal fluid (CSF) leak were reported by two studies. Other postoperative complications including meningitis, hydrocephalus, pseudomeningocele, CSF collection in subdural space, and subacute subdural hematoma were reported by one study each. Postsurgical histological analysis was reported by three studies highlighting the antiadhesive and integrative properties of HAM.

Conclusion:

The current review of evidence suggests that in terms of postsurgical outcomes, HAM is comparable with commercially available dural substitutes.

Conservative Management of Post-Operative Cerebrospinal Fluid Leak following Skull Base Surgery: A Pilot Study

Background/aims: Iatrogenic CSF leaks after endoscopic endonasal transsphenoidal surgery remain a challenging entity to manage, typically treated with CSF diversion via lumbar drainage. Objective: To assess the safety and efficacy of high-volume lumbar puncture (LP) and acetazolamide therapy to manage iatrogenic CSF leaks. Methods: We performed a prospective pilot study of four patients who developed iatrogenic postoperative CSF leaks after transsphenoidal surgery and analyzed their response to treatment with concomitant high-volume lumbar puncture followed by acetazolamide therapy for 10 days. Data collected included demographics, intra-operative findings, including methodology of skull base repair and type of CSF leak, time to presentation with CSF leak, complications associated with high-volume LP and acetazolamide treatment, and length of follow-up. Results: Mean patient age was 44.28 years, with an average BMI of 27.4. Mean time from surgery to onset of CSF leak was 7.71 days. All four patients had resolution of their CSF leak at two- and four-week follow-up. Mean overall follow-up time was 179 days, with a 100% CSF leak cure rate at the last clinic visit. No patient suffered perioperative complications or complications secondary to treatment. Conclusion: Although our pilot case series is small, we demonstrate that a high-volume LP, followed by acetazolamide therapy for 10 days, can be considered in the management of post-operative CSF leaks.

The Effect of Adding Modified Chitosan on the Strength Properties of Bacterial Cellulose for Clinical Applications

Currently, several materials for the closure of the dura mater (DM) defects are known. However, the long-term results of their usage reveal a number of disadvantages. The use of antibiotics and chitosan is one of the major trends in solving the problems associated with infectious after-operational complications. This work compares the mechanical properties of samples of bacterial nanocellulose (BNC) impregnated with Novochizol™ and vancomycin with native BNC and preserved and native human DM. An assessment of the possibility of controling the mechanical properties of these materials by changing their thickness has been performed by statistical analysis methods. A total of 80 specimens of comparable samples were investigated. During the analysis, the results obtained, the factor of Novochizol™ addition has provided a statistically significant impact on the strength properties (Fisher Criteria p-value 0.00509 for stress and 0.00112 for deformation). Moreover, a stronger relationship between the thickness of the samples and their ultimate load was shown: R2=0.236 for BNC + Novochizol™ + vancomycin, compared to R2=0.0405 for native BNC. Using factor analysis, it was possible to show a significant effect of modified chitosan (Novochizol™) on the ultimate stress (p-value = 0.005).

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.

Transethmoidal encephalocele endoscopically treated in a newborn: a case report

Congenital encephalocele is a very rare entity, with herniation of normal brain or gliotic tissue through a defect in the skull. The objective is to present a newborn child diagnosed with transethmoidal encephaloceles at birth. She developed respiratory problems, feeding difficulties, and failure to thrive since the first days of life and so required early surgery at her 33th day of life, through an endoscopic nasal approach. Technical difficulties encountered, complications, and management are discussed. To the best of our knowledge, this is the first report of endoscopic treatment of transethmoidal encephalocele in a newborn. Further studies are needed to understand the best way to repair the dural defect in this rare condition.

Applications of materials for dural reconstruction in pre-clinical and clinical studies: Advantages and drawbacks, efficacy, and selections

The dura mater provides a barrier to protect the tissue underneath and cerebrospinal fluid. However, dural defects normally cause cerebrospinal fluid leakage and other complications, such as wound infections, meningitis, etc. Therefore, the reconstruction of dura mater has important clinical significance. Current dural reconstruction materials include: homologous, acellular, natural, synthetic, and composite materials. This review comprehensively summarizes the characteristics and efficacy of these dural substitutes, especially in clinical applications, including the advantages and drawbacks of those from different sources, the host tissue response in pre-clinical studies and clinical practice, and the comparison of these materials across different surgical procedures. Furthermore, the selections of materials for different surgical procedures are highlighted. Finally, the challenges and future perspectives in the development of ideal dural repair materials are discussed.

A Sponge-Like Double-Layer Wound Dressing with Chitosan and Decellularized Bovine Amniotic Membrane for Promoting Diabetic Wound Healing

The diabetic wounds do not heal easily in part because they are susceptible to infection due to environmental influences. Wound dressing is crucial to wound healing, as it can basically protect the wound from external damages and provide a suitable microenvironment for tissue regeneration. In this study, a double-layer membrane that consists of chitosan sponge and decellularized bovine amniotic membrane (dBAM) has been developed by freeze-casting method. The results showed that the porous structure of the sponge layer improved the performances of blood coagulation and swelling. The dense dBAM can optimize the mechanical property of wound dressing. In vitro studies revealed that the bilayer membrane had favorable biocompatible, especially for human foreskin fibroblast cells (HFF-1) cell adhesion and proliferation. Moreover, the full-thickness skin defects of diabetic model mice that treated with bilayer membrane showed over 80% closure in 8 days. Our findings imply that the double-layer dressing has great potentials to be used in diabetic patients.