Is lower leg pain coming from L5/S1?

[Poobah]

My history.

7 yrs ago diagnosed with a herniated L5/S1
Surgery partial discotomy (?)  Results good and no more pain for years.

Last yr.  Low back pain, legs giving out as I walk or bend over.

Then, no more back pain, but started having lower leg pain from knee down.  Hurts when walking after a very short periof of time.  Feel aching in my shin and in the back of leg behind the knee.

Today I have the same pain, but cannot bend my knee all the way, there is numbness in the bottom of my heel (the whole heel) and tingling.  Now it has gotten to the point where my lower leg aches even at night when I am "trying" to sleep.  It is a throbbing pain that goes all the way down to my foot.

My GP doesn't think this has to do with my previous back problems because he did a physical exam on me and my leg moved without pain.  But he did not move my knee.  Just the leg up and down, side-ways.  So he ordered an MRI on ONLY my knee.  I will get those results back on the 23rd.

I know what sciatic pain it like.  It goes from the buttocks down to the foot.  But mine does not start in the buttocks, but in the knee.  At the same time I get the impression that it could be my back.  When I lift something a little heavier than "I should" I can feel the tingling in my foot.  

Can you please let me know what you think this could be?  Could it be my old back problem haunting me again?  Even if my pain does not start at the buttocks?

Thanks!

[Esteban Cheng-Ching, MD]

Continued from above due to character count liminations.
Joint problems can produce lower extremity pain, and again, history and physical exam will help with determining this.
Regarding back problems, the fact that you had surgery at one spine level does not prevent you from having problems at another disc level. The symptoms could be similar to what you had experienced before, but in a different distribution. Some patients can have symptoms from the same level they had surgery before. I cannot really say with if the symptoms you have at this moment are or not related to your previous surgery. And some patients present with low back problems but their main symptoms are in the legs, and no specifically in their "buttocks".
As I said, for the diagnosis of pain in the lower extremities, most of the information to guide the work up and eventual diagnosis, comes from a good history and a physical examination. Without being able to obtain them myself I cannot tell you what the cause of your symptoms is.
I think you should discuss your symptoms with your physician, and find out what he/she thinks you have at this moment. If symptoms persist, or no cause is found, considering an evaluation by a neurologist may help.
I hope this information is useful. Good luck.

[Esteban Cheng-Ching, MD]

Thanks for using the Forum. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the possibility to obtain a detailed history and a physical exam, I cannot tell you what the cause of your symptoms is.
Pain in both legs could be from multiple causes, and these should be investigated. History and physical exam gives a clue in most cases, and studies can be ordered accordingly depending on the possible diagnosis.
A common cause of pain in the legs, specially with exertion (walking) is problems with circulation. Vascular problem leads to decrease flow to the legs, causing pain. However symptoms commonly resolve with rest. A good exam checking pulses can make the diagnosis, if there is doubt, special tests can be performed.
Neuropathy causes pain, numbness, tingling and other sensory symptoms, and frequently affects symmetrically on both sides, in a “stocking” pattern. Sometimes depending on what nerve is affected and its distribution, patients have unilateral symptoms. The pain could be burning, throbbing or like “electric shocks”. Can fluctuate throughout the day and get worse at night. There are different types of neuropathy, and different causes, being diabetes one of the most common. Neuropathy can be diagnosed with history and physical exam. If there is doubt, and to better classify it, EMG-NCV helps. Sometimes, when these are normal, other tests are needed, including skin biopsy. To look for the underlying cause, blood tests can be performed to rule out the most common causes, however many times the cause is not found.
I will continue my answer below in another section due to character count limitations.