The importance of magnification, illumination and posture for veterinary dentistry and surgical applications.
Ergonomics involves the design of equipment, devices, and processes that support productive, effective, safe and comfortable use. The benefits of structuring the workplace with ergonomics in mind include the reduction of fatigue and discomfort as well as elimination of repetitive stress injuries. Ergonomics can be applied to many fields, including that of veterinary dentistry and surgery.
Work-related musculoskeletal injuries resulting from poor posture have been reported in surgeons, dentists, technicians, assistants, and nurses.1 The veterinary generalist as well as the veterinary surgical and dental specialist are likewise subject to various back and neck disorders from poor ergonomics.
This review article highlights basic positive ergonomic design principles for magnification, illumination, and posture for veterinary dentistry and surgical applications.
Magnification and illumination
Veterinary surgeons, generalists, and dentists are often very defensive about the use of magnification systems because they seem to imply vision impairment and/or a sign of aging.
This vanity can be challenged by citing the decreased practice-related incidence of musculoskeletal and neurologic disorders that have been measured in direct proportion to the use of proper magnification and illumination during procedures.2,3 Awkward and torque-producing operator positions, resisted by prolonged static muscle contractions, are significant occupational hazards to a surgeon’s or dentist’s physical well-being. However, there are steps you can take to support better health in your clinic setting.
Surgical telescopes
The three most important ergonomic factors to consider when investigating surgical telescopes are weight, frame design, and declination angle. Lighter scopes are more comfortable to wear, especially during longer procedures. Frames must be ergonomically designed and nose pads should conform to facial features. When considering clinical ergonomics, an adjustable declination angle option is the most important feature.
The declination angle is defined as the angle between the line of sight made by the neutral eye position, and the actual line of sight made by the declined eye chosen by the clinician. The declination angle of the telescope is too small if the operator has to tip his or her chin into the chest, and too large if the operator has to decline the eyes or flip the neck backward.
When purchasing a surgical telescope, ensure you can select and adjust the correct declination angle of the telescope to decrease neck fatigue. The magnification system should allow the user to avoid neck and shoulder pain, eyestrain, muscle strain and headache.
Third generation vertically adjustable front lens mounted (FLM) telescopes are the most ergonomically beneficial. The vertical adjustment unique to these telescopes is advantageous since it allows you to adjust the declination angle to accommodate varying work distances during different stages of the procedure. This will help minimize eye, head, neck, and back pain and strain.
Illumination
In order to avoid eye fatigue, operators should avoid intense illumination that exceeds the adaptation capability of the eye. A co-axial illumination system parallel to the operator’s line of sight, clipped directly on the surgical telescope, is recommended to avoid misalignment of light on the focal spot. Halogen and fiber optic lights are available for telescopes and controlled by portable battery packs.
Postural considerations
In addition to magnification and illumination systems, clinicians should give serious consideration to seating options. Pain in the lower back, neck and shoulders increases as a direct function of time while sitting in an ergonomically unsuitable position. Pain occurs when the spine cannot maintain its natural curvature.
The saddle-sitting position or posture has been described in many decades of medical literature as the most healthful posture for the spine. Saddle seating allows controlled movement of the pelvis, resulting in an ideal spinal position with maintenance of the lumbar curve. The saddle seat reproduces the upright standing position while the operator, dentist or surgeon is sitting down. The surgeon can bend forward and still be supported to maintain normal spinal conformation. The molded saddle design keeps the spine in the proper alignment, while allowing operator mobility. This results in the thighs, shoulders and arms finding a relaxed neutral position, and provides a mechanical advantage for the forearms and hands during delicate movements. Back pain is reduced because the operator on the saddle seat assumes a position that minimizes abnormal intradiscal pressure.
Conclusion
When ergonomic considerations are put into play, the career of the operator, dentist and/or surgeon can be extended and work satisfaction improved. Vertically adjusted FLM telescope magnification systems, correct illumination, and the utilization of a saddle seat will remove the negative postural considerations that cause acute and chronic pain in the lower back, neck and shoulders.
Author’s note: Dr. DeForge wishes to thank The General Scientific Corporation, manufacturer of Surgitel Ergovision Systems and Health by Design distributor of the Bambach Saddle Seat, for providing images for this article. IVC Journal and the author acknowledge that other manufacturers may provide similar products of equal efficacy.
Dr. Don DeForge is an independent clinical investigator and animal dentist — he can be contacted at DonDeForge100@gmail.com.
1Cornell University Ergonomics Web, ergo.human.cornell.edu.
2Chang BJ. “Ergonomic benefits of surgical telescopes: selection guidelines”. Special Ergonomics Issue. J California Dental Association, Feb 2002.
3Chang, BJ. “Ergonomics of Surgical Telescopes and Headlights”. General Scientific Corp., Pub No: 120100.
Further references
Chang BJ. “New advances in surgical telescope and ergonomics”. Presented at the International Intradiscal Therapy Society and International Society for Minimal Intervention in Spinal Surgery-Combined Meeting. St John’s College, Cambridge, England, August 1999; 1-5.
Gale M. “The seated spine and the Bambach Saddle Seat”. National Library of Australia, ISBN: 0646-32703-8. Chairs, Chair Design, Human Engineering, 1997; 22,26.
Gale M, Feather JS, Coster G. “A Multidisciplinary approach to the design of a work seat to preserve lumbar lordosis”. Australian Occupational Therapy Journal. 1989; 36: 45-52.
Pheasant S. Ergonomics, Work, and Health. Gaithersburg MD: Aspen Publishers, 1991.
