Sham Treatment Works Just As Well As Neurodynamic Technique for Carpal Tunnel Syndrome
One out of every 200 adults in the United States suffers from carpal tunnel syndrome (CTS). Carpal tunnel syndrome has received a lot of attention in recent years because of suggestions that it may be linked with occupations that require repeated use of the hands, such as typing on a computer keyboard or doing assembly work. Actually, many people develop this condition regardless of the type of work they do.

Carpal tunnel syndrome (CTS) causes pain, numbness, tingling, and weakness of the hand and wrist. Symptoms begin when the median nerve gets squeezed or pinched inside the carpal tunnel of the wrist. CTS is also referred to 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 carpal tunnel is an opening through the wrist to the hand that is formed by the bones of the wrist on one side and the transverse carpal ligament on the other. The median nerve passes through the carpal tunnel into the hand. It gives sensation to the thumb, index finger, long finger, and half of the ring finger. It also sends a nerve branch to control the thenar muscles of the thumb. The thenar muscles form the thick pad at the base of the thumb and let you touch the pad of the thumb to the tips of each finger on the same hand, a motion called opposition.

Hand therapists such as specially trained physical and occupational therapists often treat patients with carpal tunnel syndrome. A wide variety of treatment techniques are used such as splinting, activity modification, and stretching of the soft tissues. Neurodynamics, a relatively new treatment method has become very popular in the last 10 years and is the focus of this study.

Neurodynamics was developed in Australia by a physical therapist by the name of David Butler. It is the study of how the nervous system slides and glides as we move. Nerves such as the median nerve involved in carpal tunnel syndrome can become pinched, obstructed, or bound down by scar tissue, swelling, or other soft tissues surrounding the nerve. The neurodynamic technique is a way of restoring the free flowing movement of nerve tissue as the joint moves.

Treating carpal tunnel syndrome with the neurodynamic approach requires the therapist to understand the anatomy of the median nerve. Before applying the technique, the therapist must conduct an examination of the median nerve including palpation and movement of the nerve. Tests are also performed to see if the nerve is involved, blocked, or obstructed in any way.

Altered nervous system movement is restored through a series of joint and limb positions and movements referred to as neurodynamic technique (NDT). In order to see if this technique really works or not, the authors designed a study to compare a very believable sham technique with the real neurodynamic approach. Patients were completely blinded as to which group they were in (receiving neurodynamic technique or receiving a very believable sham). Patients in both groups had high expectations that the treatment they received would be helpful. Expectations were measured using a specific questionnaire (the Patient-Centered Outcome Questionnaire or PCOQ) designed for that purpose.

To give an idea of what a neurodynamic technique looks like, the authors provided photographs and a written description of the physical maneuver performed on the patient (depending on which group he or she was in). All treatments were conducted with the patient lying down on his or her back.

For the neurodynamic technique, the patient bent his or her head away from the side the therapist was mobilizing. The shoulder was pressed down by the therapist. The arm was lifted up away from the side, the forearm was turned up in a movement called supination (palm up as if asking for a bowl of soup). The therapist kept the downward pressure on the shoulder while moving the arm through a specific pattern of passive elbow, wrist, and hand motion. The purpose of these specific movements is to position the upper extremity in such a way that movement of the joints stresses the targeted nerve pushing it along its intended pathway.

Patients in the sham group kept the head in the middle. The therapist did not raise the patient's arm away from the body, and did not depress the shoulder down while moving the wrist and hand. None of the movements in the sham treatment stressed or moved the nerve. In fact, the movements were carefully designed to minimize any anatomical stress across the nerve. Patients in both groups received two sessions each week for three weeks.

Patients with carpal tunnel syndrome (all women) were randomly chosen by a computer program to be in one of the two groups. Two thirds of the group had carpal tunnel syndrome in both wrists/hands. The patients had no way of knowing which group they were in and whether or not the treatment received was the neurodynamic technique or the sham until the study was over. Only the therapist performing the techniques knew which technique was being used on patients.

Results were measured by pain intensity, pressure pain, thermal pain, grip strength, and self-report measure of arm disability (loss of function in daily activities). The pain measurements were carefully taken using various measuring tools and instruments (e.g., Visual analog scale for pain intensity, pressure algometer for pressure pain, handheld neurosensory analyzer for thermal pain). Another handheld tool called a dynamometer was used to measure grip strength.

Specific tests of neurologic status of sensory function were also performed. The reserachers used standard Semmes-Weinstein monofilament testing of fingertip sensation and electrodiagnostic nerve conduction study (NCV) of the median nerve. All tests were done before treatment (baseline testing) and again three weeks later after treatment. Pain intensity, pressure pain, and thermal pain were measured right after each treatment session to assess for within-session treatment effect.

Analysis of results showed no difference in immediate or delayed outcomes between the two groups. Patients in the sham group got just as much pain relief and change in perceived pain pressure, temperature, and sensitivity. The authors suggest this shows how much pain and symptom relief depends on patient expectations. Testing showed no difference in the two groups in terms of expectations for treatment results. In other words, they all expected the treatment to work and to get better and they did. That is a true indication of how believable the sham treatment was.

The authors conclude that like many manual therapy hands on techniques, it's not the specific method used that works as much as the patient's response to being touched and their expectations of getting better as a result. The results of this study are consistent with other similar studies using a variety of different manual therapy techniques. This study shows that the success of the neurodynamic technique may not be related to movement of the nerve at all.

The authors also pointed out there are some caveats (yes, buts) in this study. First, all of the patients were women, so the results don't necessarily apply to men (similar testing must be done to observe response in men). Second, all patients in the study did use a splint on the forearm, wrist, and hand at night while sleeping and during any activities that provoked or aggravated the carpal tunnel syndrome symptoms.

Third, there were no control groups (group(s) who receive no treatment at all or group with splints but no hands on treatment). Without a control group for comparison, it is uncertain that the results are completely accurate. The patients could have gotten just as much relief from symptoms just with the passage of time. And finally, with only a three-week follow-up period of time, the results do not show whether the treatment effect is long-lasting. But this was the first study to even look at results from neurodynamic technique, so the findings are important. More studies are planned by this group to take a look at other factors and variables as suggested.
Joel E. Bialosky, PT, PhD, et al. A Randomized Sham-Controlled Trial of Neurodynamic Technique in the Treatment of Carpal Tunnel Syndrome. In Journal of Orthopaedic & Sports Physical Therapy. October 2009. Vol. 39. No. 10. Pp. 709-723.