Work-related musculoskeletal disorders (WMSDs) are just now being considered in veterinary dentistry, general practice and veterinary specialty practices.
Even though this review emphasizes WMSDs in veterinary dentistry, it is easily applied to many other daily medical or surgical tasks in veterinary hospitals.
If you suffer from neck pain at night, back stiffness in the morning, wrist pain or numbness and tingling in your fingers, you may be a victim of WMSDs. WMSDs have been studied in human medicine and human dentistry for the past 15 years. In a recent survey of human dental hygienists, 79 percent reported having carpal tunnel syndrome (CTS).
CTS results from compression of the median nerve, which begins in the brachial plexus of the spine where the neck meets the shoulder. It then continues the length of the arm parallel to the brachial artery, through the carpal tunnel of the wrist and into the hand, where it innervates the thumb, index finger, middle finger and ring finger.
Melanie Simmer-Beck, R.D.H., M.S., of the Univeristy of Missouri-Kansas City School of Dentistry, says that “CTS hand pain can originate from hand injury [repetitive motion disorders, or RMDs] or from other aspects of poor operator posture.”
WMSDs and hand problems are avoidable by maintaining a neutral posture while sitting in the dental operatory or surgical suite.
Studies have documented that the neutral position of slightly less that 90 degrees is the best position for the head, trunk, arms and hips. There are times, howver, when this position cannot be routinely maintained in the clinical setting.
On the other hand, ignoring the ideal limitation and moving far beyond the neutral position can be dangerous in the long-term.
Make a Difference
Ergonomics is the science that deals with the interaction of humans with their working environment. Once you have identified the problems in your hospital and dental operatory, action may be taken to make the workplace ergonomically positive.
With attention to special chairs and surgical loupes, you can maintain a healthy neutral posture. Even individuals with advanced WMSD may benefit from making these changes.
Investing in a quality, ergonomically designed surgical loupe can improve the working posture.
SurgiTel Systems in Ann Arbor, Mich. offers a line of adjustable declination angle (the angle at which the eyes will be declined) surgical loupes that allow correct neck posture and visual aid. As the procedure changes, the declination angle can be adjusted to accommodate the operator. This ability to adjust the declination angle helps avoid eye, head, neck and back pain and strain.
SurgiTel’s loupes have co-axial illumination. A co-axial system, which is parallel to the operator’s line of sight, is directly clipped onto the surgical telescope to avoid misalignment of the light system on the focal spot. Co-axial illumination is available in both halogen and fiber optic light sources.
Many practitioners and staff may say that they do not need magnification because their vision is fine. But even with the best vision, bending over to see a small object within a surgical field may lead to poor neck and back posture. Studies have shown that WMSDs decrease proportionately with proper magnification and illumination. I recommend starting with a 2.5X system.
When the spine does not maintain its natural curvature, pain in the lower back, neck and shoulders occurs. Advanced, ergonomically designed doctor and assistant’s chairs can help.
Bambach Saddle Seat Co. in Australia has shown that a saddle sitting position in which the angle at the hip joints is about 45 degrees and the hips are in a position of wide abduction removes most of the spinal musculoskeletal risk factors associated with long-term sitting.
This places the pelvis in a stable upright orientation that maintains neutral spinal curvature even when leaning forward to work. The feet are then beneath the body’s center of mass providing superior support without the need for armrests freeing the hands for precise work.
The saddle seat reproduces the upright standing position when the dentist or assistant is sitting down. The molded saddle design keeps the spine in proper alignment while allowing mobility. Back pain is reduced because the person sits with the least pressure on vertebral discs.
SurgiTel also offers Ergocomfort Chairs designed to allow correct posture and decrease WMSDs.
A plethora of ergonomic computer equipment is on the market today.
RMDs can occur from the use of the keyboard or computer mouse. Pacifica, Cailf.-based Evoluent offers its Vertical Mouse, designed to place the mousing arm in a natural position and prevent repetitive stress injuries (RSI) by creating better ergonomic posture.
Ergonomic keyboards are also available from companies such as ErgoCarpal by Morti and Co. in Albuquerque. Standard computer keyboards can cause strain on the wrists leading to CTS. Ergo-innovations in keyboards are helping to reduce the stress and strain on hands. Split ergo-keyboards give a wider key angle with a natural position of the hands.
Trackball keyboards and trackball-style mice can also assist in ergonomic help for CTS operators. Other technology offered by Ergoweb.com includes adjustable supports for notebook computers that elevate the screen for better neck and head posture.
Very soon ergonomic training will become commonplace in veterinary clinics. Take a moment and review the repetitive motions involved in your daily tasks and set up an ergo-plan to attack these target zones.
The Correct Grasp
The modified pen grasp is important when using dental hand instruments or power instruments and is one of the first techniques taught in human preclinical dental education. Without utilizing this grasp correctly, sustained musculoskeletal compromise during the active working strokes in root planing may occur during routine daily prophylaxis appointments.
In the modified pen grasp, the thumb and index finger hold the instrument handle. The finger pads, not the sides, make contact with the instrument for maximum control. The fingers are opposite each other near the junction of the shank (thinner portion of a hand instrument joining the blade to the handle).
The handle should rest between the second and third knuckles. The middle finger is placed on the shank with the finger pad resting against the shank. This is the important finger utilized to guide the instrument. The ring finger is a fulcrum and used to guide the operator’s hand. It is placed in a secured position in the patient’s mouth.
Always select an ergonomically positive relaxed hold—not a rigid “death-grip”—on the instrument. If your finger tips are blanched, relax, hold the instrument lightly and restart the working stroke used in root planing.
The next time you go to your own dentist for a prophylaxis ask him to demonstrate the modified pen grasp and its application in human periodontal professional care.
Stacy A. Matsuda, RDH, BS, a clinical instructor at Oregon Health and Science University School of Dentistry states, “Ergonomically sound instrumentation applies the principles of lever dynamics to achieve effective, sound activation without undue exertion of the musculoskeletal system.
“In order to apply these principles, precise positioning must be followed, making the often-overlooked components of finger contact points and handle rest of primary importance. Fine tuning these elements of grasp can preserve musculoskeletal health and permit achievement of efficient and predictable root preparation.”
One major factor in all ergonomic solutions is cost and budget constraints. Veterinarians agree with ergonomic principle but question affordability.
Ergonomic corrections are an ongoing approach to make your hospital free of musculoskeletal compromise. The question is not “How can I afford ergonomic solutions?” but, “How can I not afford to develop a positive ergonomic operatory setting today?”