You may find that the url looks like this format:
yoursite.com/t/{this-might-be-your-topic-title}/{topid_id}/{post_number}?xxxxxxx
In fact topic-title has no effect. So you can safely replace it with other non-empty strings. Query parameters can also be deleted safely, such as…
yoursite.com/t/-/{topid_id}/{post_number}
If your post_number is 1, then it can also be deleted…
yoursite.com/t/{topid_id}
Shortened!