This letter is written in response to a recently published report by Bolat et al. [1] regarding mitomycin-C, sodium hyaluronate and human amniotic fluid in preventing epidural fibrosis and adhesion using a rat laminectomy model, which published in December 2013 in the "Asian Spine Journal". In this study, the authors evaluate the effects of two treatments, mitomycin-C, sodium hyaluronate and human amniotic fluid, on preventing spinal epidural fibrosis. They concluded that implantation of mitomycin-C, sodium hyaluronate and human amniotic fluid reduces epidural fibrosis and adhesions after spinal laminectomy in rat models. Although this is a highly useful study, there are several issues that deserve further clarification by the authors.

First, we wanted to inquire how the mitomycine-C, sodium hyaluronate or human amniotic fluid was dissolved? This is an important question because different vehicles mayaffect the results.

Second, the authors should give more detailed information about the dosage or density of sodium hyaluronate and human amniotic fluid used in the study. This information would be helpful in further research efforts. Third, according to the description found in the articles "Materials and Methods" section, authors applied mitomycine-C on the operation level topically and waited for three minutes. However, the time of topical application of sodium hyaluronate and human amniotic fluid is just three minutes?

We appreciate the authors' important contribution to this field of study, including supplying us with additional information in preventing epidural fibrosis. However, many studies such as the optimal concentration of different agents, the safety of agents and so on are needed in further studies for clinical practice.