Amniotic Membrane Grafting in the Management of Conjunctival Vascular Malformations

Comparison of the effects of preservation methods on structural, biological, and mechanical properties of the human amniotic membrane for medical applications

Amniotic membrane (AM), the innermost layer of the placenta, is an exceptionally effective biomaterial with divers applications in clinical medicine. It possesses various biological functions, including scar reduction, anti-inflammatory properties, support for epithelialization, as well as anti-microbial, anti-fibrotic and angio-modulatory effects. Furthermore, its abundant availability, cost-effectiveness, and ethical acceptability make it a compelling biomaterial in the field of medicine. Given the potential unavailability of fresh tissue when needed, the preservation of AM is crucial to ensure a readily accessible and continuous supply for clinical use. However, preserving the properties of AM presents a significant challenge. Therefore, the establishment of standardized protocols for the collection and preservation of AM is vital to ensure optimal tissue quality and enhance patient safety. Various preservation methods, such as cryopreservation, lyophilization, and air-drying, have been employed over the years. However, identifying a preservation method that effectively safeguards AM properties remains an ongoing endeavor. This article aims to review and discuss different sterilization and preservation procedures for AM, as well as their impacts on its histological, physical, and biochemical characteristics.

Two-Year Outcomes of Transcutaneous Non-Image Guided Bleomycin Sclerotherapy in Conjunctival Lymphatic Malformations: A Protocol-Based Management in 16 Eyes

OBJECTIVES

To study the efficacy and the 2-year outcomes of treating conjunctival lymphatic malformations (LM) with protocol-based bleomycin sclerotherapy.

METHODS

A retrospective interventional study of 16 eyes with conjunctival LM treated with bleomycin sclerotherapy between December 2016 and 2019. A clinical resolution was assessed as poor (less than 25% decrease in size), fair (25%-50% decrease in size), good (50%-75% decrease in size), excellent (more than 75% decrease in size), and complete resolution.

RESULTS

Mean age at presentation was 18 ± 13.09 (15 years, 3 to 59 years) years. The conjunctival component was classified based on clinical appearance as conjunctival mass (12) and microcystic LM (4). Mean clock hours of involvement were 3.32 ± 5.29 clock hours (4, 2-9 clock hours). An average per session dose of 1.8 ± 0.3 IU (median 2 IU, range 1-2 IU) and a cumulative dose of 3 ± 1.5 IU (3, 1-6 IU) of bleomycin were injected over an average of 1.6 ± 0.7 (median 2, range 1-3) treatment sessions per patient. Excellent response was observed in 11 (69%) cases. A residual lesion requiring surgical debulking was noted in 1 case. Recurrence was noted in 2 (13%) cases one of which was treated with repeat sclerotherapy resulting in complete resolution. Adverse reactions included restricted extraocular motility in extreme gaze in 2 eyes (13%). Sustained tumor resolution was observed over a mean follow-up of 29.24 + 9.45 months (24, 24-38 months).

CONCLUSIONS

Bleomycin sclerotherapy gives excellent response in conjunctival LMs and is an effective first-line therapy in these cases.

Bleomycin sclerotherapy for eyelid venous malformations as an alternative to surgery or laser therapy

PURPOSE

To evaluate the clinical outcome of patients with venous malformation (VM) involving the eyelid treated with bleomycin sclerotherapy.

METHODS

A retrospective review was performed of 18 consecutive patients with VM involving the eyelid who underwent bleomycin sclerotherapy. Patients' clinical presentation, details of sclerotherapy, and post-sclerotherapy resolution of the lesion as well as any procedure-related complications were evaluated.

RESULTS

Twelve women and six men of mean age 34.3±20.4 years underwent sclerotherapy with bleomycin. Chief complaints were cosmetic disfigurations with or without hemifacial deformity (n=2), pain in engorgement area (n=2), pain and swelling from venous thrombosis (n=2), swelling or engorgement obstructing their eyesight (n=2), or eyelid dysfunction (n=1). The lesions were only in the eyelid in three patients; otherwise they were extended out of the eyelid either superiorly (n=3), laterally (n=8), inferiorly (n=8), and/or posteriorly to the orbit (n=8) to various extents. Conjunctival involvement was present in 13 patients. 14 patients had received prior treatments including surgery, laser therapy, or non-bleomycin sclerotherapy. With an average three sessions of bleomycin sclerotherapy (average total dose 34.5 mg), more than 80% shrinkage was observed in seven patients (38.9%), 50-80% shrinkage in eight patients (44.4%), and 30-50% shrinkage in two patients (11.1%). One patient had recurrence, which was successfully treated again with bleomycin. No procedure-related complications were noted.

CONCLUSIONS

The use of bleomycin appears to be a simple, safe, and effective treatment for venous malformations involving the eyelid, avoiding more elaborate and challenging surgical or laser interventions, and is even effective in full thickness lesions.

Repair of oral mucosal defects with cryopreserved human amniotic membrane grafts: prospective clinical study

The aim of this study was to evaluate the clinical outcome of the surgical repair of oral mucosal defects using cryopreserved human amniotic membrane (HAM) as a graft material. Thirty-four patients with precancerous lesions such as leukoplakia, erythroplakia, and verrucous hyperplasia were included. Fresh amniotic membrane was obtained from women undergoing elective caesarean section; the membrane was cleaned, prepared in antibiotic solutions, and preserved at -80°C. Results suggested that HAM promotes healing and epithelialization without specific complications. Thus we conclude that the use of HAM gives promising results in the repair of post-surgical oral mucosal defects.

Ocular surface reconstruction using amniotic membrane following excision of conjunctival and limbal tumors

PURPOSE

To report the clinical results of patients treated by preserved human amniotic membrane transplantation (AMT) following the removal of conjunctival and limbal tumors.

METHODS

Retrospective noncomparative interventional case series of 9 patients (9 eyes) who underwent AMT after removal of conjunctival and limbal tumors with lesion-free margins and perilesional cryotherapy.

RESULTS

The excised tumors were histopathologically examined and included 2 squamous cell carcinomas, 2 papillomas, and 5 nevi. Bulbar conjunctiva was involved in all of the eyes, limbus and cornea in 7 and 3 eyes, respectively. The mean extent of the limbal involvement was 4 clock hours (range 2-9, SD 2.4); the average diameter of the base of the tumor was 12.8 mm (range 10-20, SD 4.4). The mean follow-up time was 38 months (range 13-60, SD 15). No surgical or early postoperative complications were observed. In all eyes, complete healing of the tissue defect occurred, resulting in a stable, wet, and noninflamed epithelium. All eyes demonstrated a smooth ocular surface except one with a clinically insignificant symblepharon after the excision of a squamous cell carcinoma. Superficial peripheral corneal vascularization and opacification as a sign of partial limbal stem cell deficiency developed in 2 eyes. In one case, a recurrence of conjunctival papilloma was diagnosed after a 3-year follow-up.

CONCLUSIONS

Amniotic membrane transplantation is an effective method of reconstruction following a conjunctival and limbal tumor excision and cryotherapy of surgical wound margins. In most cases, complete healing of an ocular surface can be achieved without any clinically significant complications.

Use of human amniotic membrane as an interpositional material in treatment of temporomandibular joint ankylosis

PURPOSE

The aim of the study was to demonstrate whether the human amniotic membrane (HAM) as an interpositional material could prevent temporomandibular joint (TMJ) reankylosis in the randomized rabbit model.

MATERIALS AND METHODS

In our experimental study, 24 New Zealand white rabbits were used and all right joints were operated. The rabbits were divided into 2 groups. The first group was specified as the demonstration group (n = 8). In this group, fibrous ankylosis formation was shown experimentally. The rabbits in the second group, the treatment group (n = 16), were divided into 2 subgroups: gap arthroplasty, performed in group A (n = 8); and HAM, used as an interpositional arthroplasty material in group B (n = 8).

RESULTS

In all rabbits, the range of jaw movements and weight decreased after induction of ankylosis. After surgical treatment of fibrous ankylosis, the vertical, right, and left movements of the jaw and weights of rabbits increased immediately. The results were evaluated clinically, macroscopically, histologically, and radiologically. There was a statistically significant difference in the jaw movements between groups A and B (P < .05). All operated joints in group A showed fibrous adhesions across the gap, and the articular surface was irregular with osteophytes and bony islands on the joint surface. In group B, no fibrous adhesions were observed.

CONCLUSION

It was concluded that interpositional arthroplasty with HAM was superior to gap arthroplasty in the rabbit model in preventing ankylosis.