As far I can tell, this hasn't been discussed in any WB forums yet.
About 6 weeks ago I awoke with shooting pain down my right hip, thigh, and leg. After bearing it for 2 days, I checked into the emergency room, received shots and steroids, subsequently visited the ortho, got x-rays and an MRI. Bottom line: it's official - I've got a herniated disk in my lower back. Per the doc, the cause isn't a sudden event like bending the wrong way or even backpacking several hundred miles. Over time, disks can deteriorate. I suppose if I sat with better posture and hadn't jogged (which I don't do anymore) this may not have happened but who knows?
Surgery is a last resort. For now, I'm taking strong prescription-level Vitamin I. If this fails to reduce the inflamation, the next step is a shot. As the doc explained, the problem isn't the bulging disk itself but its impingement on the nerve. There's no pain now - the only sensation is numbness in my right little toe and the adjacent areas of the foot. I've done one 3-day backpack (50 miles in VT & NH about 2 weeks ago) and continue to work out on the stair climber and elliptical.
Surely I'm not the only WBer out there with this problem. I'd appreciate any insight, advice, experience from WBers on this, especially how it affected your hiking.