The Science and Clinical Applications of Placental Tissues in Spine Surgery

The current alternative for ocular surface and anophthalmic socket reconstruction, cryopreserved umbilical amniotic membrane (cUAM)

PURPOSE

This report presents the results of using cryopreserved umbilical amniotic membrane (cUAM) as an alternative mucosal graft for ocular surface reconstruction in cases of anophthalmic socket contracture (ASC), cicatricial entropion (CE), and conjunctival-scleral defects.

METHODS

The study included patients who underwent non-commercial implantation of cUAM grafts (prepared by corneal banking methods) for ASC, CE, conjunctival defect, and scleral melting. The main success criteria for this study were the comfortable fitting of the ocular prosthesis in ASC patients, the natural eyelid position in CE patients, and the degree of conjunctivalisation in melting patients.

RESULTS

cUAM transplantation was performed in 2 patients who could not use a prosthetic eye due to conjunctival contracture, 2 patients with CE, and 1 patient with conjunctival defect and 1 patient with conjunctival-scleral melting. The primary outcome was achieved in 83.3% (5/6) of patients. In one patient with CE, partial healing was achieved due to the persistence of CE in the medial upper eyelid.

CONCLUSIONS

cUAM is a viable alternative to mucosal grafting for reconstructing the bulbar and palpebral conjunctival surface, fornix, and orbit, with reduced donor morbidity and shorter surgical time. Its regenerative ability allows for tissue defect healing and improves cosmetic appearance through epithelialization within weeks.

The Effect of Amniotic Tissue on Spinal Interventions: A Systematic Review

BACKGROUND

Amniotic membrane tissue has been thought to potentiate healing in many soft tissue conditions. Specifically, recent studies have shown its therapeutic potential for treatment in the setting of spinal pathologies. The purpose of this study is to thoroughly review the existing scientific literature and evidence concerning the clinical use of amniotic membrane-derived biologic agents on postoperative outcomes following spinal surgery.

METHODS

A systematic review was conducted following preferred reporting items for systematic reviews and meta-analyses guidelines using PubMed, Embase, and Cochrane databases up to December 2020 to identify animal and clinical studies examining the therapeutic potential for amniotic membrane tissue in the setting of spinal pathologies (including disc herniation, prevention of epidural fibrosis, and spinal fusion). Studies were broken down into 2 categories: experimental model type and the type of amnion product being analyzed.

RESULTS

A total of 12 studies (4 clinical studies and 8 studies utilizing animal models) met inclusion criteria. Additionally, the major types of amnion product were divided into cryopreserved/freeze-dried amniotic membrane, human amniotic fluid, human amniotic membrane, cross-linked amniotic membrane, and amnion-derived epithelial cells. While heterogeneity of study design precludes definitive specific results reporting, most studies showed positive benefits on healing/outcomes with amniotic augmentation. Specifically, amnion products have shown promising effects in reducing epidural adhesions and scar tissue after spine surgery, improving spinal fusion rate and postoperative pain scores, and promoting better functional outcomes after spine surgery.

CONCLUSIONS

A review of the limited number of reported studies revealed a wide variety of amniotic membrane preparations, treatment regimens, and indications, which limit definitive conclusions. To date, while there is no definitive clinical proof that amniotic tissues enhance tissue repair or regeneration, the aggregate results demonstrate promising basic science and outcomes potential in spinal surgery. Further study is warranted to determine whether this application is appropriate in the clinical setting.

CLINICAL RELEVANCE

This systematic review provides a summary of the existing literature regarding the use of amniotic membrane preparations, treatment regimens, and indications within spinal surgery. With the growing popularity and utilization of biologic agents such as amniotic membrane-derived products in orthopedic and neurologic surgery, this systematic review gives physicians a concise summary on the outcomes and indications associated with amniotic membrane products.

LEVEL OF EVIDENCE: 4

Placental-based allograft use for tissue regeneration and scar prevention for neurosurgical wounds

Tweetable abstract Proper wound healing, including internal and surface tissue regeneration with the minimization of scar formation, is one of the most significant topics in surgical discussions and EpiFix^® dehydrated human amnion/chorion membrane allograft promotes healthy healing.

Raman spectroscopy of healthy, injured and amniotic membrane treated rat spinal cords

Spinal cord injury is a significant public health issue with high psychological and financial costs to both the family and the society. Effective treatment strategies are hence of immense value. Several reports have suggested application of amniotic membrane for treating injuries, and there is evidence that it may be used to treat spinal injuries. In this animal model study, we explore biochemical changes in amniotic membrane treated injured spinal cord with respect to untreated injured and uninjured spinal cord using Raman spectroscopy. Multivariate statistical analysis is able to classify control, untreated, and treated with 92%, 87%, and 80% efficiency, respectively; suggesting unique biochemical changes in each group. Such studies may lead to development of minimally invasive methodologies for spinal cord injury treatment monitoring.

Elucidating the Pivotal Neuroimmunomodulation of Stem Cells in Spinal Cord Injury Repair

Spinal cord injury (SCI) is a distressing incident with abrupt onset of the motor as well as sensory dysfunction, and most often, the injury occurs as result of high-energy or velocity accidents as well as contact sports and falls in the elderly. The key challenges associated with nerve repair are the lack of self-repair as well as neurotrophic factors and primary and secondary neuronal apoptosis, as well as factors that prevent the regeneration of axons locally. Neurons that survive the initial traumatic damage may be lost due to pathogenic activities like neuroinflammation and apoptosis. Implanted stem cells are capable of differentiating into neural cells that replace injured cells as well as offer local neurotrophic factors that aid neuroprotection, immunomodulation, axonal sprouting, axonal regeneration, and remyelination. At the microenvironment of SCI, stem cells are capable of producing growth factors like brain-derived neurotrophic factor and nerve growth factor which triggers neuronal survival as well as axonal regrowth. Although stem cells have proven to be of therapeutic value in SCI, the major disadvantage of some of the cell types is the risk for tumorigenicity due to the contamination of undifferentiated cells prior to transplantation. Local administration of stem cells via either direct cellular injection into the spinal cord parenchyma or intrathecal administration into the subarachnoid space is currently the best transplantation modality for stem cells during SCI.

Repeated Freezing Procedures Preserve Structural and Functional Properties of Amniotic Membrane for Application in Ophthalmology

For decades, the unique regenerative properties of the human amniotic membrane (hAM) have been successfully utilized in ophthalmology. As a directly applied biomaterial, the hAM should be available in a ready to use manner in clinical settings. However, an extended period of time is obligatory for performing quality and safety tests. Hence, the low temperature storage of the hAM is a virtually inevitable step in the chain from donor retrieval to patient application. At the same time, the impact of subzero temperatures carries an increased risk of irreversible alterations of the structure and composition of biological objects. In the present study, we performed a comprehensive analysis of the hAM as a medicinal product; this is intended for a novel strategy of application in ophthalmology requiring a GMP production protocol including double freezing–thawing cycles. We compared clinically relevant parameters, such as levels of growth factors and extracellular matrix proteins content, morphology, ultrastructure and mechanical properties, before and after one and two freezing cycles. It was found that epidermal growth factor (EGF), transforming growth factor beta 1 (TGF-β1), hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF), hyaluronic acid, and laminin could be detected in all studied conditions without significant differences. Additionally, histological and ultrastructure analysis, as well as transparency and mechanical tests, demonstrated that properties of the hAM required to support therapeutic efficacy in ophthalmology are not impaired by dual freezing.

Progesterone Prolongs Viability and Anti-inflammatory Functions of Explanted Preterm Ovine Amniotic Membrane

Amniotic membrane (AM) is considered an important medical device with many applications in regenerative medicine. The therapeutic properties of AM are due to its resistant extracellular matrix and to the large number of bioactive molecules released by its cells. An important goal that still remains to be achieved is the identification of cultural and preservation protocols able to maintain in time the membrane morphology and the biological properties of its cells. Recently, our research group demonstrated that progesterone (P₄) is crucial in preventing the loss of the epithelial phenotype of amniotic epithelial cells in vitro. Followed by this premise, it has been evaluated whether P₄ may also affect AM properties in a short-term culture. Results confirm that P₄ preserves AM integrity and architecture with respect to untreated AM, which showed alterations in morphology. Transmission electron microscopy (TEM) analyses demonstrate that P₄ also maintains unaltered cell-cell junctions, nuclear status, and intracellular organelles. On the contrary, an untreated AM experienced an extensive cell death and a strong reduction of immunomodulatory properties, measured in terms of anti-inflammatory cytokine expression and secretion. Overall, these results could open to new strategies to ameliorate the protocols for cryopreservation and tissue culture, which represent preliminary stages of AM application in regenerative medicine.

Novel Use of Cryopreserved Ultra-thick Human Amniotic Membrane for Management of Anophthalmic Socket Contracture

PURPOSE

To describe the use of cryopreserved ultra-thick human amniotic membrane for management of anophthalmic socket contracture.

METHODS

A chart review was performed to identify patients undergoing fornix reconstruction with cryopreserved ultra-thick human amniotic membrane for management of anophthalmic socket contracture. Patient demographics, disease etiology, and data regarding postoperative prosthesis fit and complications were collected.

RESULTS

The technique is described in 3 female patients with anophthalmic socket contracture who underwent fornix reconstruction using cryopreserved ultra-thick human amniotic membrane. All patients had excellent prosthesis fit at final follow up (range, 10-14 months). There were no clinically significant complications and no reoperations were performed. One pyogenic granuloma developed and was excised without affecting ocular prosthesis fit.

CONCLUSIONS

Cryopreserved ultra-thick human amniotic membrane is easy to use, well tolerated, and produces good outcomes for management of anophthalmic socket contracture.

The Use of Umbilical Amnion for Conjunctival Socket, Fornix, and Eyelid Margin Reconstruction

PURPOSE

To describe outcomes using umbilical amnion for conjunctival fornix, socket, and eyelid margin reconstruction.

METHODS

A medical record review was performed to identify patients who had received umbilical amnion over a 2-year period in their department. Patient demographics, disease etiology, and data regarding surgical outcomes were collected. The primary outcome was the success rate of the surgical intervention.

RESULTS

Twenty-one patients received umbilical amnion for anophthalmic socket contracture (n = 16), orbital implant exposure (n = 3), ocular surface burn (n = 1), and cicatricial entropion repair (n = 1). The primary outcome was met in 76% of patients overall. In anophthalmic socket contracture, the primary outcome was met in 86% and 0% of patients with acquired and congenital anophthalmia, respectively. The primary outcome was met in all cases of orbital implant exposure and cicatricial entropion. The primary outcome was not met in a Roper-Hall grade IV ocular surface burn.

CONCLUSIONS

Umbilical amnion is an ideal substrate graft for reconstruction of the conjunctival fornix, socket, and eyelid margin. Umbilical amnion appears to be efficacious for the management of socket contracture in acquired anophthalmia, orbital implant exposure, and cicatricial entropion. Further experience is needed to determine the efficacy of umbilical amnion in ocular surface burns.