CH APTER FI VE Get t i n g t h e Up p er Hand on Pai n The right half of the brain controls the left half of the body. This means that only left-handed people are in their right mind. SOURCE UNKNOWN our hands are integral to your work. Because of sustained grips and prolonged awkward postures dentists and hygienists must Yemploy throughout the day, hand, wrist and arm pain are much more prevalent among these professionals than in the general public.1 Between 23 percent and 40 percent of dentists experience hand and wrist pain;2-5 however, among hygienists, the problem is even more prevalent. Nearly 75 percent of hygienists experience hand and wr i st pai n, 6 which are the most common sites of pain reported among hygi eni st s. 6-9 This frequency is nearly four times the prevalence found in the general working public. Fewer dental professionals fully recover from hand pain syndromes than they do from pain in the neck, shoulder, and elbow.7 Therefore, prevention strategies and early attention to warning signs of the pri- 75 PRACTI CE DEN TI STRY PAIN-FREE mary CTDs of the hand and arm are imperative to your health and career longevity. One would think that pain in the hand, wrist or arm would be due to a problem in the same area, but the origins of pain are often elusive. In fact, the source of the symptoms may be nowhere near where the symptoms are perceived. For example, one of the symptoms of carpal tunnel syndrome, numbness in the fingers, sometimes has nothing to do with a problem in the hand or wrist, but may be due to a problem in the cervical spine, thoracic outlet or trigger points in the forearm. There are numerous causes of hand, wrist and arm pain, including tendonitis (e.g., DeQuervain’s Tenosynovitis), arthritis (e.g., osteo- arthritis of the basilar joint), nerve compression (e.g., thoracic outlet syndrome, cervical radiculopathy, carpal tunnel syndrome, cubital tun- nel syndrome), trigger points (e.g., Radial Tunnel Syndrome), and equipment issues (non-ergonomic tools, poorly fitted gloves) which will be described later in this chapter. However, the most commonly diagnosed CTD of the hand, wrist and arm among dentists and hygien- ists is carpal tunnel syndrome. Carpal Tunnel Syndrome Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment in the arm10,11 and contributes to one of the most frequently performed surgeries on the hand in the United States.12 Caused by compression of the median nerve at the wrist, 13 CTS can lead to pain, numbness, or tingling in the thumb, index, middle, and half of the ring finger. (Fig. 1) One study found that while 71 percent of dentists experienced one or more CTS symptoms, only 7 percent were actually diagnosed with CTS. 14 This should prompt dental professionals with CTS-type symp- toms to educate themselves on all possible etiologies to avoid unnec- essary surgery or ineffective therapies. Inconsistencies abound in CTS literature regarding its cause, prop- er evaluation and course of care.15-17 Noted author and physical reha- bilitation expert Dr. Rene Calliet states, “…differentiation of median nerve wrist compression from cervical radiculitis or thoracic outlet 76 GETTI N G TH E UPPER HAND ON PAIN Fig. 1: Pain or tingling in the distribution of the median nerve (shaded) is often indicative of carpal tunnel syndrome. Numbness is usually felt in the fingertips only. Ca r p a l Tu n n e l Li gament Fl exor Tendons Fl exor Tendons Medi an Ner ve syndrome may be the most challenging in clinical practice.” 15 This is largely due to the fact that the median nerve fibers run a long and twisting course around bone and through soft tissue from the cervi- cal spine down to the fingertips. CTS symptoms may not always be indicative of a structural problem in the hand and wrist; often the problem originates more proximally in the muscles/tendons that sta- bilize the arm during repetitive work.17 Any compression or entrap- ment along the median nerve fibers can result in CTS-type symptoms in the hand.18 The Carpal Tunnel The carpal tunnel is comprised of a row of bones on the back of the wrist, and a thick ligament in the front. For the hand to function prop- erly nine flexor tendons and the median nerve must be able to glide easily within this space, Of these structures, the median nerve is the soft est and most vulner able t o pr essur e. You can see for yourself the positions that cause the most pressure in the carpal tunnel. Straighten your right wrist and place your left thumb over the transverse carpal ligament. Now bend your right wrist 77 PRACTI CE DEN TI STRY PAIN-FREE back and feel the ligament tighten over the tunnel. This is the position that compresses the tunnel most. Now make a fist. Did you feel the tunnel get even tighter? If you hold this position long enough, you may eventually feel your hands and fingers go numb. Sustained grip- ping while extending the wrist is unhealthy for your median nerve. Bring your wrist to neutral, then forward. You will feel the tightness slacken when you are in neutral, then slightly tighten again as you move downward. Now try the above exercise gripping a pencil. This “precision” grip creates more pressure in the carpal tunnel. You have just demonstrated two of the four primary risk factors for CTS in dental professionals—flexing the wrist forward while gripping a small instrument forcefully. The other two risk factors are high repeti- tion (as in manual scaling) and duration (i.e., how many heavy calculus patients you schedule back-to-back. (Fig. 2) These risk factors cause microtrauma in the carpal tun- Fig. 2: Four of the primary risk factors nel: fibrosis and edema of the contributing to CTS in dentistry lining of the tendons at the High Repetition wrist eventually cause increased Force pressure within the carpal tun- nel and decreases the blood Duration flow to the median nerve with- Flexed Wrist in the tunnel. The swelling of the lining of the tendons is • Increased pressure in often painful, and it is the pres- carpal tunnel sure on the median nerve at • Thickening/inflammation of tendon sheaths the wrist from this swelling that • Median nerve causes numbness in the fingers compression and weakness of t he muscles at the base of the thumb. CTS symptoms (pain, numb- PAIN, NUMBNESS, TINGLING IN HAND & 31/2 FINGERS ness and tingling) ar e oft en worse at night and first thing in the morning. Weakness in a precision grip may be present Carpal Tunnel Syndrome due to atrophy or weakness 78 GETTI N G TH E UPPER HAND ON PAIN 19 of the thumb abductor muscles. Over time, visibly decreased mus- culature may be noticed at the base of the thumb. Sensory impair- ment is usually experienced before motor loss, so early intervention is important. The causes of CTS are numerous and include anatomic, physiolog- ic, hereditary and traumatic factors that result in compression or irrita- tion of the median nerve at the wrist. For instance, CTS is three times more prevalent in women than in men, more common between the ages of 30 and 60, among diabetics and in obese people. However, the literature also reports an occupational cause in more than 47 percent of cases.20 In addition to any therapies you may consider, it is imperative that you address ergonomic issues known to aggravate carpal tunnel symptoms. You can use the following strategies in the operatory to minimize your risk for CTS. Keys t o Success: Preventing Carpal Tunnel Syndrome The four primary risk factors that contribute to occupational CTS in dentistry can be minimized with appropriate ergonomic interventions. Avoid sustained wrist flexion Wrist flexion increases pressure in the carpal tunnel. (Fig. 3, left) Working with your wrist bent toward the little finger—called ulnar deviation—also increases this pressure.12,13 When you perform scaling or other treatment, try to keep your wrist straight and move your entire hand, wrist and forearm as a unit. This transfers the load from smaller hand muscles t o lar ger ar m and shoulder muscles. Usi ng a fi n- ger rest position (either inter- or extra-oral) to stabilize the instrument further reduces thumb pinch force and muscle workloads in the hand.21 Extra-oral fulcrums also facilitate neutral wrist posture and allow proper positioning for precision instrumentation. 22 (Fig. 3, right) 79 PRACTI CE DEN TI STRY PAIN-FREE Fig. 3: Poor (deviated) posture of the wrist is a primary risk factor for CTS in dentistry. Try to maintain neutral posture of the wrist (right), especially when scaling Rather than twisting the wrist to access hard-to-reach areas, try moving the instrument or handpiece in your hand. To access molar regions and distal pockets, select an instrument with multiple accen- tuated angles and longer terminal shank (Fig. 4), which can reduce twisting the wrist to access these areas. It makes far more sense to use an accent uat ed angled i nst r ument rather than angling your wrist. Fig. 4: Instruments with You can retrain yourself to main- multiple exaggerated angles tain near-neutral wrist postures using and longer terminal shanks a soft wr i st wr ap, such as a Wri sTi mer, can reduce t he need t o f lex to limit wrist flexion anywhere from 0 the wrist to access hard-to-reach distal pockets degrees to 20 degrees.