**5. Plastic and reconstructive surgery**

Bovine amnion function as biological dressing holds great potential in reconstructive surgery. There has been several clinical studies including bovine amnion membrane for burn patients [62–64]. Rao published a study in 1981 regarding the use of bovine amnion on burn and pressure ulcer patients. The study revealed biostatic ability to control infection and faster granulation process [6]. Another study by Zhu et al. showed significant difference of burn wound treated with bovine amnion compared with vaseline gauze dressing as control. The different results studied were healing time, infection ratio and residual burn wound [62]. Bovine amnion as burn biological dressing was also proven having similar efficacy as human amnion. A study by Park et al. displayed similar histological grading, epithelization rate and infection rate [22].

Ablative laser used for removing superficial skin has notable adverse effect even though its efficacy is better than non-ablative laser. Adverse effect such as postoperative erythema is caused by complete elimination of epidermis and upper dermal layer [65]. Bovine amnion membrane was found clinically effective in reducing erythema due to its anti-inflammatory mechanism [26].

## **6. Head and neck surgery**

Amnion is also applied in head and neck surgery. Although, some of them used human amnion. One of such use was documented as the use of amniotic membrane compared with collagen membrane, in a study conducted by Munoyath consisted of twenty patients with facial soft tissue injury with whom all patients had either single or multiple soft tissue loss all over the face. The size of the wounds ranged from 7 mm × 10 mm to 80 mm × 150 mm and depth of the wound ranged from 2 to 5 mm. the results showed pain score of greater than 3 was observed in 50% of the patients in Amnion group and in 80% of the patients in Collagen group. The average time for appearance of healthy granulation tissue over the wounds that were treated with Amnion dressing was 5 to 9 days and for Collagen group was 7 to 12 days. Though vascularity was not compromised in both the groups, the height of the wound at 3-month follow up showed a clinically significant difference (100% patients in AM group had flat wound whereas only 80% showed normal wound height); though statistically not significant [66].

In recent years, research of amniotic membrane in head and neck surgery, especially bovine amniotic membrane, has increased. The use mostly relates to wound dressing. Further research could evaluate the use of bovine amniotic membrane

in head and neck surgery in the years to come. The amniotic membrane compared with collagen membrane, with both materials combined with deproteinized bovine bone mineral was compared in clinical trials by Kim for the treatment of periodontal inflammations. Both the use of amniotic membrane and collagen membrane combined with deproteinized bovine bone mineral improves the condition of periodontium. The amnion did not cause a significant gum recession. Another use of amniotic membrane for oral cavity problem was studied for temporomandibular joint ankylosis, which is a serious condition, mainly due to injuries responsible for the reduction of mandible functionality [67, 68].

A bovine amniotic membrane study for facial abrasions was done in a Korea, comparing the use Amnisite BAtm with foam and gel dressings. The study demonstrated all patients were well healed completely after appliance of dried bovine amniotic membrane or foam dressing without any complication. However healing time for patients treated with dried bovine amniotic membrane was significantly shorter and no significant difference between the two groups regarding treatment costs, scar formation, skin elasticity or moisture content was noted. This study demonstrate the potential practical clinical use of bovine amniotic membrane as a facial soft tissue trauma as one of potential dressing [69].

### **7. Neurosurgery**

In the field of neurosurgery, autologously harvested amniotic membrane has been used to repair duramater defects in myelomeningocele. Although the human cranial neurosurgery applications of amniotic membrane have not been thoroughly investigated, an in vivo rat cranial surgery model demonstrated that human xenograft amniotic membrane was efficacious and had an adequate safety profile. Eichberg put forward their retrospective pilot study about the use of allograft amniotic membrane for the augmentation of dural repair in craniotomies. The reported rates of postoperative CSF leaks differ among studies and craniotomy locations; leaks may prevailed as many as 4–17% craniotomy for posterior fossa lesions. In 122 craniotomies, including 18 craniotomies for posterior fossa lesions, none were complicated by postoperative CSF leaks. These results suggest that amniotic does not contribute to the increased risk of CSF leaks. Further, the interpretation of the data is complicated by the fact that the patients in the study received a sheet of bovine collagen dural substitute layered on top of the dehydrated amnion membrane; thus, the outcomes may be due to both materials. While this retrospective pilot study does not prove the superiority of dehydrated amnion over other dural adjuncts, or the efficacy of use, they demonstrate that it has an adequate safety profile with no complications directly related to its use in closures for craniotomies. They also report very low CSF leak rates and infection rates, particularly in craniotomies for infratentorial lesions [70–72].
