Besides iTunes, you can also back up iPhone files with 3rd party tools. iTransfer is helpful on this issue. This software is used for transferring files among iOS devices, iTunes and computers, and it will help users to back up iPhone music, videos and so on to computer easily.
1. Run iTransfer and connect iPhone to computer with the USB cable. Click the name of iPhone and choose files you want to backup in the left sidebar. Then contents will show up in the right part.
2. Press "Ctrl" and click to choose certain files, then click the transfer button in the right bottom of the interface to back up the files. Or right-click the files you want to backup, and choose to "Transfer to > My Computer".
3. In the dialog of transfer settings, choose the location on the computer to put the iPhone backups. Check "Save to Folder" and click "Change" to choose the target folder. If users want to backup the files to iTunes as well, check the "Save to List" and choose "iTunes". Click "Transfer Now" to start the iPhone backup.
http://www.leawo.org/tutorial/how-to-backup-locked-iphone.html