Measuring Results After Carpal Tunnel Surgery
If surgery is done for carpal tunnel syndrome, how can we tell if it worked? The more obvious answer is whether or not the patient's symptoms (usually wrist/hand pain, numbness and tingling) improve.

Standardized research can rely on just asking the patient to rate his or her pain from zero to 10 or zero to 100. Two tools currently in clinical use to measure the results of treatment for carpal tunnel syndrome. The first is the 6-item carpal tunnel symptoms scale (referred to as CTS-6). The second is the 2-item palmar pain scale.

The CTS-6 measures change in symptoms after surgery, while the 2-item text is a measure of pain caused by the surgery. A study carried out by Swedish researchers was designed to assess how effective these two tests are in measuring symptoms related to carpal tunnel syndrome (CTS) and surgery for carpal tunnel surgery.

This particular group of researchers were the ones who developed the 6-item CTS symptoms scale in the first place back in 2009. It is a more streamlined and valid test than the previously used 11-item CTS severity scale. Since then, they followed 447 patients and measured the outcomes of surgical treatment for CTS.

Everyone in the study had an open incision approach (rather than minimally invasive) surgery. Almost everyone had the surgery under local anesthetic. Prior to surgery, they had all tried using a wrist splint without success.

There was no attempt to try hand therapy before surgery and no formal rehab program after surgery. Patients were given some exercises to do after surgery and advised to slowly increase their activities until able to resume all previous functions.

As predicted by the study authors, both tools were valid and reliable. The CTS-6 score reflected greater satisfaction after surgery in the patients who had the greatest pain relief and return of function. And as you might have expected, the longer patients were away from the surgery date, the less pain they reported on the 2-item palmar pain scale.

Results of these tests were also compared with the QuickDASH, another tool available to measure before and after results of carpal tunnel syndrome. They found that the QuickDASH is a better measure of disability. So comparing the QuickDASH to either the CTS-6 or the 2-item palmar pain scale was a bit like comparing apples to oranges (both fruit but not the same thing at all).

There was some speculation as to why some patients did not improve with surgery. It was suggested that some may have been given the wrong diagnosis (and therefore the wrong treatment). Problems in other parts of the arm (shoulder, elbow) may have been the real underlying cause of symptoms.

Others may have been clouded in their judgment by their perception -- they actually had experienced measurable improvement in symptoms. But they got used to the gradual change and remained unsatisfied with any amount of pain no matter what amount of recovery had already been experienced.

In summary, the 6-item CTS symptoms scale is very responsive to change in CTS symptoms after surgery. Since the 6-item tool is faster than the previously 11-item scale, it is advised to make use of the shorter, yet still reliable tool.

Further analysis of the data collected from the 2-item palmar pain scale showed that maximum pain relief occurs between six and 13 months. There is some pain relief between three and six months post-op but the bulk of improvements comes a little later.
Isam Atroshi, MD, PhD, et al. The Six-Item CTS Symptoms Scale and Palmar Pain Scale in Carpal Tunnel Syndrome. In The Journal of Hand Surgery. May 2011. Vol. 36A. No. 5. Pp. 788-794.