Well, I went back to him today, this time armed with my three MRI results. After examining me, he told me I no longer have a weak butt. But, based on the MRIs and his examination, he thinks I have piriformis syndrome, which is where the piriformis muscle impinges on the sciatic nerve in the leg. I thought this was what I had in OCTOBER--but the various doctors had me convinced that, instead, I had (in chronological order): a weak butt, a herniated disk, a tear in the hip labrum, and a tear in the hamstring by the ischial tuberosity. I don't believe it's taken eight months of doctor examinations, MRIs, X-rays and physical therapy to to get me to what I thought I had before I even started seeing anyone. This is beyond frustrating.
Dr. Metzl had some good news, though:
1. It can be treated. Dr. Metzl scheduled me for an ultrasound-guided steroid injection into the sciatic notch at HSS for July 2nd. From some online research I've done (here and here), it seems that this injection is used to both diagnose and treat the piriformis syndrome. If the pain goes away, then it'll confirm that an inflamed piriformis muscle was impinging on the nerve. In some cases, the shot itself is all that is needed for the pain to go away permanently. In other cases, however, the pain goes away and comes back, which may mean surgery is required to release the piriformis and decompress the nerve. Hopefully that's not what I'll need.
2. I can still run! Dr. Metzl noted that in eight months, the pain hasn't really gotten any worse. Because of that, he told me to "keep doing what you're doing"--which to me means I can still run, although I will stay away from speed and hill workouts, and not go crazy on the races. I do still plan to do as much swimming and biking as I can, since those don't cause as much pain as running does. But it's good to know that I now have a doctor's OK to keep running. I think I may be able salvage a decent summer and fall running season after all. :-)