Found this interesting paper written about Anterior Web Formation (glottoplasty?) written by a well known speech therapist in Sweden. They do not recommend it.
http://www.agnodice.ch/IMG/pdf/img025.pdf (http://www.agnodice.ch/IMG/pdf/img025.pdf)
Though it should be taken into consideration that the study is over 7 years old..-
Interesting but very short paper without too much background sadly. No details on the surgery was given and no data on the voice quality. One key part I think is the one about if people are not able to control their voices to a higher pitch pre op, they may not get that ability post op, thus not profiting from surgery either. I think this has a lot to do with prosody as well (speech melody). If it lacks pitch variation it sounds more male. Also as a conclusion of that I would say that the Glottoplasty may be for people who can control their voices and who actually are able to reach a female pitch in therapy or training, but are sick of the effort and strain it takes. Conversely the surgery would have to be applied with words of caution to people who simply cannot get their voices up in pitch or melody - thos who typically are more desparate to get something changed surgically :\
Here is the one from Dr Gross in 1999 - it is a bit more positive in terms of the pitch gain, but shows a bit the issues about reduced volumen and pitch range.
http://www.jvoice.org/article/S0892-1997%2899%2980028-9/abstract
(On Wiki: http://wikisend.com/download/562950/charite-1999-vfs.pdf)