What To Do When Carpal Tunnel Symptoms Don't Go Away After Surgery
Imagine this patient scenario: a 50-year-old woman had surgery for carpal tunnel syndrome (CTS) but didn't get better. She now goes to a different surgeon for help. What should the surgeon do? Is another surgery needed? This is a report of a case just like this at the Mayo Clinic in Rochester, Minnesota. Knowing that this happens from time to time, and there have been no studies to guide surgeons, Dr. Peter Amadio wrote up the case. He presented the various factors to consider and his final decision about the best way to treat this particular patient for other surgeons to consider when faced with similar situations.

Carpal tunnel syndrome is a common problem affecting the hand and wrist. Symptoms begin when the median nerve gets squeezed inside the carpal tunnel of the wrist. This is a medical condition known as nerve entrapment or compressive neuropathy. Any condition that decreases the size of the carpal tunnel or enlarges the tissues inside the tunnel can produce the symptoms of CTS.

The patient in question had symptoms very typical of CTS. There was numbness in the thumb, index finger, and middle finger. The symptoms came on with activities like holding a book or driving the car. They were especially bothersome at night, waking her up and keeping her awake. Over time, the symptoms got worse and worse until she finally had surgery to release the retinaculum. The transverse carpal ligament (also known as the flexor retinaculum) is a strong band of connective tissue normally present across the palmar side of the wrist. Cutting through the retinaculum takes pressure off the nerve underneath it. This procedure is called nerve decompression.

At first, there was improvement in her symptoms after surgery. But it didn't last and six months later, she went to the Mayo Clinic for help. The surgeon evaluated her and then asked himself several questions. First, did she really have carpal tunnel syndrome or was something else going on? Second, if the diagnosis was correct, why wasn't the surgery successful? When considering this second question, there are several possibilities to consider.

Even though her first surgery was performed as an open procedure with a half inch long incision, it's possible the retinaculum was not cut completely through. This is referred to as an incomplete release. It's also possible that scar tissue called fibrosis formed around the nerve as a result of the tissues being disrupted by the surgery. New symptoms or symptoms that are worse after surgery might suggest a third potential source of symptoms: injury to the nerve as a result of surgery.

One place to look for some answers is with the results of electrodiagnostic tests done before surgery. These tests show how well the nerve is firing and give an indication of how much the nerve's function has been affected by the compressive forces on the nerve. Repeating the tests after surgery and getting a before and after picture of nerve function can help diagnose intraoperative nerve injuries. But, in this case, the woman did not have any preoperative electrodiagnostic tests performed, so there was no way to make this comparison.

Another way to look at this case is to review the timing of the recurrent symptoms. She reported some relief after the first surgery, but it wasn't 100%. Her same symptoms came and went, and then got worse. That type of clinical picture suggests to the surgeon that the symptoms are more likely persistent rather than recurrent. In other words, the problem wasn't fully corrected with the surgery and the symptoms present were still from the original carpal tunnel syndrome.

There's really no way to know if fibrosis is an issue without opening up the wrist and taking a second look inside. If a second release is done, the surgeon can confirm or rule out scar tissue as a potential cause at that time. It's also possible to check to see if the nerve was indeed injured and treat that problem as well when the revision operation is performed.

There is one more thing surgeons must take into consideration in cases like this. And that's the mental health status of the patient. Patients who are not happy with the results of their first CTS surgery are often those who have another diagnosis: mood disorders. Depression is the most common mood disorder and seems to be linked with a lack of improvement or even increased symptoms after surgery for CTS. If depression is present, a second surgery may not be in the patient's best interests.

So, what happened with this patient? Well, Dr. Amadio went ahead and ordered electrodiagnostic tests. Even though there was no before test to compare with this new after test, he could tell by the results that nerve function was not affected. Combining the results of the patient interview (history) with current signs and symptoms, a simple repeated nerve decompressive procedure was advised. The surgeon approaches such a procedure knowing that careful observation of the structures during the operation would also guide further treatment (e.g., if there was a nerve injury or further need to protect the exposed nerve).

This case from the Mayo Clinic points out the need to define once and for all what to do in cases where carpal tunnel syndrome is not helped by surgical release. Since it doesn't happen very often (less than five per cent of all cases), large studies to help figure out what treatment works best have not been possible. Surgeons are forced to rely on case studies like this one with expert opinion to guide them when making the treatment decision(s) on a case-by-case basis.
Peter C. Amadio, MD. Interventions for Recurrent/Persistent Carpal Tunnel Syndrome After Carpal Tunnel Release. In The Journal of Hand Surgery. September 2009. Vol. 34. No. 7. Pp. 1320-1323.