Question
Here is my story:

Back on November of '06, I was lifting a Christmas tree in my home and felt sudden, sharp, debilitating pain in my lower back.  It was so painful I had difficulty straightening up.  I took three days off of work for complete bedrest, lots of advil, and by the fourth day I seemed better.  I never saw an MD.

The pain never really completely went away from that injury, but it was manageable.  

Around 4 months later, I still hadn't gotten 100% better, I went to see my primary care physician, and told him that I suffered from "moderate pain in the lower back, mostly on the left side, worse while sitting, better while standing or laying down.  I also have tingling and numbness in my left leg while sitting (sciatica)"

My PCP recommended an MRI.  I got the MRI of my lumbar region and it showed a large (8mm) extruded disk at the L4-L5 level.  My PCP referred me to an Osteopathic surgeon.  I had a consult with the osteopath at the beginning of march of 07.

The osteopath said we could try surgery or physical therapy.  Since the pain was not debilitating anymore, and really didn't interfere with my life, I opted for physical therapy.

The physical therapy was fine for several weeks; I thought I was experiencing minor improvements, when on march 27th of this year I had a sudden onset of a very troubling and traumatic symptom:  Out of nowhere I suddenly had nearly continuous urinary frequency.  The strong, persistant urge to urinate (even with an empty bladder) plagued me during every minute of every waking hour.  I couldn't eat. I couldn't concentrate.  It was torture.  It just came on one day and didn't stop.

I saw a urologist and he tested my urine and said it was clean: no infections.  He gave me some Detrol LA which did not help at all.  My urologist suspected that this urinary frequency was relating to my back injury.  Since I didn't have any pain or noctural frequency problems, he ruled out Interstitial Cystitus.

I consulted with my Osteopath and he too agreed this could be relating to some sort of pinched or pressed nerve that leads to the bladder.  We scheduled disk surgery ASAP.  On April 2nd, I had the disk surgery...I can't remember the procedure but the surgeon said he basically "removed the part of the disk that had become extruded" but he did not touch the disk.  He also noted that my L4-L5 disk appeared to be degenerating.  He said I am suffering from "degenerative disk disease" there and that led to the extruded disk.

The good news is that the back pain and leg tingling vanished...but the bad news is that the urinary frequency did NOT.  Since then, I have seen four urologists, none of them can explain why I have urinary frequency. All of them think this is related to my back.  My osteopath DIDN'T think it was related to my back because he said after he removed the pressure from the extrusion everything looked fine.  

My post-surgery physical therapist thinks it could be Pelvic Floor Dysfunction brought on my the back injury.  My acupuncturist thinks it's a pinched nerve in my back at the L4-L5 level.

Any ideas on what this could be?  Could an L4-L5 injury affect nerves to the bladder?  If so, how does one treat that (especially if I've already had surgery to fix the extruded disk problem)?  Should I see a neurologist?  I have read that sciatica can affect the detrusor muscle in the bladder and cause urinary frequency.  Vesicare did not help me at all, and Elmiron (that I'm taking in case it IS interstitial cystitis) does not really help either.

Answer
Dear Mark,

In my opinion, the bladder urgency is most likely related to the previous disk injury.  Even though the extruded portion of the disk has been removed, a focal injury to the nerve supply that innervates the smooth muscle of the bladder wall can cause urgency and frequency symptoms.   There is actually a name for conditions such as this:  Cauda Equina Syndrome (CES)!

CES is caused by significant narrowing of the spinal canal that compresses the nerve roots below the level of the spinal cord. Numerous causes of cauda equina syndrome have been reported, including traumatic injury, disk herniation, spinal stenosis, spinal tumors, inflammatory conditions, infectious conditions, and accidental causes by medical intervention.

Concerning disk herniations here are a few statistics I was able to research:  CES results from a herniated lumbar disk in 1-15% of cases. Of lumbar disk herniations, 90% occur either at the vertebral levels L4-L5 or L5-S1.  Seventy percent of cases of herniated disks leading to cauda equina syndrome occur in people with a history of chronic low back pain, and 30% develop cauda equina syndrome as the first symptom of lumbar disk herniation. Males in their 30s and 40s are most prone to cauda equina syndrome caused by disk herniation.

Most cases of cauda equina syndrome caused by disk herniation involve large particles of disk material that have completely separated from the normal disk and compress the nerves (extruded disk herniations). In most cases, the disk material takes up at least one-third of the canal diameter, and if left in the canal for an extended period of time can permanently damage the nerves.  This is a possibility in your case.

Treatment for this is exactly what you have been through:  initial conservative care such as physical therapy, chiropractic care, or spinal decompression, and if those options do not work, then surgery.  In your case, I think there may be continued pressure, inflammation or scar tissue around the nerve roots which is the continual source of the problem, and I agree with the urologists that there is most likely not any organic bladder problem causing your symptoms.  

I think the best diagnostic testing would be to get another MRI to specifically look at the nerve roots, spinal cord and peripheral nerves to the bladder.   I would consult with a radiologist to see if there is a special technique to visualize those structures rather than a normal T1 or T2 weighted MRI sequence.  There is a study called a FLAR study which works real well to see inflammation/scaring in the ligaments of the spine, and that may be an option as well to look at the nerve tissue more closely.  Again the radiologist is the expert to ask.  I don't think a neurologist is going to be of any additional value in the further exploration of this problem, but then again if all else fails, another opinion can't hurt.

Good luck Mark...keep in touch as I am interested in the outcome of this.  If you have any additional follow-up questions, please feel free to write back.

Respectfully,
Dr. J. Shawn Leatherman
www.suncoasthealthcare.net