As a manual physical therapist that works in NYC, I tend to work very long hours and also use my hands anywhere from 10-13 hours a day working on my patients. One of the biggest occupational hazards related to my field is developing arthritis in the thumb joints and also carpal tunnel syndrome. Next to my mind, the health of my hands are critical for permitting me to effectively work. The average person spends close to 70 percent of time in their life in whatever vocation they choose. The problem with the computer era is workers are expected to be more productive in less time, and it usually has a domino effect in that this never slips in reverse in an employer/corporate expectation, so our bodies continue to churn out at a rate that oftentimes leads to tissue breakdown, or worse, neurological compromise. In a nutshell, we sit too much and partake in too many of the same repetitive tasks. Our bodies are designed for motion, not remaining static for long periods. One of the sneaky neurological injuries that can pervade corporate America is carpal tunnel syndrome.
Carpal tunnel syndrome (CTS) is a compressive injury to the median nerve that occurs on the front or anterior part of the wrist. This tunnel is formed anatomically by the bones of the wrist and houses the median nerve, which begins up in the neck and travels the length of the arm and courses through this cave-like structure at the wrist. The carpal tunnel not only houses the median nerve but also nine tendons of the hand that help us flex or bend our fingers -- "CTS is a common upper extermity entrapment neuropathy and is estimated to occur in 1 to 3 percent of the general population." [1] [4] The signs and symptoms associated with CTS usually include parethesia (tingling, numbness) and pain within the area of the hand the median nerve innervates, which includes the thumb, index, middle and outer half of the ring fingers. [4] [7] Nighttime pain and parethesias are also a common complaint, and it has been suggested "shaking the hand back and forth" upon waking up can help alleviate the discomfort. [4] Ultimately, if left unchecked and ignored, the median nerve compression can lead to significant weakness and disability in the hand. Once nerves are irritated they can be slow to heal, so the old adage is applicable in CTS: An ounce of prevention is worth a pound of cure.
Who is most at risk for developing CTS?
Earlier this month, the Wall Street Journal reported on a study published in the Archives of Physical Medicine and Rehabilitation that people with "short, wide hands and square-shaped wrists may be more prone to CTS, especially if they are workers who perform repetitive hand motions." According to the article, CTS affects three times as many women as men. One of the tests that can confirm CTS is an electromyogram or EMG that tests the nerve conduction velocity and determines where along the path of a nerve it may be getting injured or compressed. Other physical examination tests are also done to elicit pain consistent with CTS. Two of the more common clinical tests are the Phalen test and Tinel sign. The Wall Street Journal stated the above article also reported certain morphological characteristics that correlated with increased risk for CTS. Two of the features assessed were hand and wrist ratios:
Hand ratios were determined by dividing hand length by palm width, and was found to be significantly smaller in CTS patients than controls. Wrist ratio was defined by the depth of the wrist divided by the by the width at the base of the hand.
The findings determined significantly larger wrist ratios in CTS patients. Last, the study suggested "carpal tunnel patients were shorter and had a higher BMI (body mass index) than controls."
Prevention tips to help decrease risk of symptoms of CTS
Researchers have determined that the neutral (0 degree) position of the wrist minimizes pressure within the carpal tunnel, so it is critical to try to keep the wrist in this position for repetitive activities such as typing or using the computer mouse, as well as while sleeping if you are at risk of CTS. [2] [3]
Rempel, et al recorded lower pressures in the carpal tunnel with the forearm pronated (turned down and in) at 45 degrees and the metacarpophalangeal (knuckle) joints flexed or bent to 45 degrees. [8]
Susan Michlovitz, PT, Ph.D., certified hand therapist and professor at Temple University, advocates interventions that "alter nerve compression by altering wrist and forearm position, activity levels, avoidance of repetitive gripping and forceful pinching or finger loading while pushing down on the keyboard especially out of neutral wrist position as these have all been shown to increase pressures in the carpal tunnel." [4]
Dr. Michlovitz professes if these elements are complied with it may help alleviate the symptoms related to CTS and also can be done as a preventative measure for those who jobs place them at risk. [4] Other modifications include avoiding resting the wrist on a hard surface or edge of the table/keyboard. Using a split keyboard is advised to prevent having the forearm fully pronated (facing downward), and taking regular breaks is suggested to perform nerve and tendon gliding exercises. [5] As previously mentioned, wrist splinting is also commonly employed to relieve symptoms of numbness/tingling and pain in the finger and hand. Most over-the-counter wrist splints found in your local pharmacy typically have the wrist up in 20 degrees of extension. It is best to get a splint that keeps the wrist in neutral for best positioning. [1] [2] [4] I typically wear these splints at night to help prevent inadvertently compressing the carpal tunnel while sleeping due to the hand and wrist being positioned down in a bent or flexed manner. Shaking the hand and arm intermittently is also advised to help decrease nerve tension while at work or upon waking up in the morning. [4]
Treatment for those who develop Carpal Tunnel Syndrome
As previously mentioned, treatment intervention for CTS should focus on educating the patient on how to decrease the pressure within the carpal tunnel. Like any orthopedic disorder, the sooner one seeks proper treatment, the better the outcomes, and this is especially true when dealing with a nerve injury.
It is important to first control the inflammation and pain that the patient reports affects their function. Home exercises are instructed to the patient for mobility and strength as well as the use of ice/heat and activity modifications to help quell the local inflammation at the carpal tunnel and improve circulation to the median nerve. However, it has been suggested that if the "patient continues to work in a poorly aligned posture and does grip and strengthening activities it is possible they may exacerbate their condition." [4] [5]
Other treatment interventions include splinting, modalities such as ultrasound or laser, carpal bone mobilization (these are the bones that make up the wrist and carpal tunnel), and exercises to help stretch the wrist flexors and strengthen the wrist and finger extensors. I often find doing soft tissue mobilization also is helpful along the forearm to help decrease muscle restriction, and mobilize scar tissue, which can help improve tolerance to nerve gliding exercises to augment nerve healing. The physical therapists will also spend time educating the patient on her/his posture to avoid factors that affect alignment and make suggestions to create the most effective and ergonomic work-site.
Your physical therapist or occupational therapist will do some specific nerve gliding stretches that should be done carefully not to exacerbate the nerve pain. When done correctly, these nerve glides often will help improve the nerve conduction velocity, the speed of the nerve getting the signal to the muscles it innervates. The patient can also be instructed in self tendon gliding of the finger flexor tendons and nerve gliding of the median nerve exercises. [4]
Seradge, et al have shown that these exercises have "demonstrated via measurements of carpal tunnel pressure in vivo (in live tissue) that intermittent exercise of active wrist and finger motion for one minute can lower pressure in the carpal tunnel." [4] [6] The researchers recommended "frequent one-minute bouts of active motion throughout the day." [6] These exercises are thought to have a "positive effect on CTS, in part, by facilitating venous return and reducing swelling in the median nerve." (Please refer to video for instruction on exercises for tendon-nerve gliding, and stretching.)
It is important NOT to do repetitive grip strengthening exercises such as the use of therapy putties or hand resistance grippers as this type of exercise has been demonstrated to increase the pressure within the carpal tunnel. [4] [6] Another option to help the patient tolerate the pain and possibly hasten their conservative intervention are steroid injections. [2] [4] When used in cases of mild CTS, steroid injections have shown some efficacy in the short term. [2] In addition, "for CTS occurring in the last trimester of pregnancy, this may be a viable alternative to control symptoms until after delivery, when many of the symptoms typically resolve." [4] [9]
Remember, the key is preventing CTS from hopefully occurring in the first place, so try to use these evidenced-based exercises and suggestions for your workspace in the below video on how you work to stay out of trouble.
For more by Michael Zazzali, click here.
For more on personal health, click here.
References:
1) Ferg S, Pritchard T, Keenan J, Croft P, Silman AJ. Estimating the prevalence of delayed median nerve conduction in the general population. Br J Rheumatol. 1998; 37:630-635.
2) Gelberman RH, Aronson D, Weisman MH. Carpal Tunnel Syndrome. Results of a prospective trial of steroid injection and splinting. J Bone Joint Surg Am. 1980; 62: 1181-1184.
3) Gelberman RH, Hergenroeder PT, Hargens AR, Lundborg GN, Akeson WH. The Carpal Tunnel Syndrome. A Study of Carpal Tunnel Pressures. J Bone Joint Surg Am. 1981;63:380-383.
4) Michlovitz S. Conservative Intervention For Carpal Tunnel Syndrome. JOSPT. 2004; 39: 589- 600.
5) Wehbe MA. Tendon Gliding Exercises; Am J Occup Ther. 1987; 41: 164-167.
6) Seradge H, Jia YC, Owens W. In Vivo Measurement of Carpal Tunnel Pressure in the Functioning Hand. J Hand Surg (AM). 1995; 20: 855-859.
7) Katz JN, Losina E, Arnick BC, 3rd, Fossel AH, Bessette L, Keller RB. Predictors of outcomes of carpal tunnel release. Arthritis Rheum. 2001; 44:1184-1193.
8) Rempel D, Bach JM, Gordon L, So y. Effects of forearm pronation/supination on carpal tunnel pressure. J hand Surg [Am]. 1998;23:3-42.
9) Burke DT, Burke MM, Stewart GW, Cambre A. Splinting for carpal tunnel syndrome: in search of the optimal angle. Arch Phys Med Rehabil. 1994; 75: 1241-1244.