I had a discectomy done on my L5/S1 disc along with a foraminotomy to open up the passages in the vertabrae that the nerve branches off into from the spinal cord ... my disc was actually ruptured, not herniated ... the surgery was the best decision of my life ... I was in constant pain from my sciatica nerve for over 9 months ... the surgery was done right as I was getting "slapfoot" where I was starting to lose use of my leg and foot ...
I awoke from surgery at 10:30 am and was walking down the hall unassisted at noon ... it took about month for the nerve pain to subside since my nerve was soooo swollen and irritated ... after 2 months, the nerve pain would come and go, but for the most part was not there and after 3 months, I had no nerve pain at all ...
After the surgery, I was told to walk as much as possible ... I was not allowed to do anything more than that for a month. After a month, I was allowed to ride a bike on smooth terain, but not for long ... more walking ... and I started to stretch. I slowly started stiff legg bends with a super correct form ... everything since then has had to be with the absolute strictest of form ...
NO EXCEPTIONS!
You will find that if all your excercises are done with the strictest of form, that injury is highly unlikely at all ...
At the beginning of my third month, I started going back to the gym, but only did excercises that did not involve loading my lower back ... for instance, I would do flat bench, but would not do incline as that would increase the load on my disc ... this meant I could do leg extensions (light), but not shoulder presses ... you have to be inventive and extremely (if not overly) cautious during this time ... I also at this time started to add weight to my stiff leg bends (which made then stiff leg deads), and only small weight ... I actually started out with 5 lb dumbells in each hand ... and every day, I would increase the weight slightly ... eventually I moved up to the straight bar ... even though I could lift more, it was not my lower back I was trying to strengthen ... it was my core and the other muscles supporting my spine ...
About 6 months later I was lifting up some 70 lb dumbells for incline presses and heard a pop ... it was not a serious injury but very painful for about a month ... I tore some of the ligaments that wrap around the backbone ... I twisted and lifted instead of bending, lifting and turning my whole body after ... moral of this story ... "execute every movement in proper form"
My surgery was 12/5/02 ... now a year and a half later, my back is better than it has ever been ... I now deadlift 365 for 10 - 12 reps and squat 405 for 8 - 10 reps deep with no pain in my disc at all ... take your time and you will be fine ... good luck ...