NOTES, CASES, I N S T R U M E N T S NEW SURGICAL ILLUMINATOR* MIGUEL MARTINEZ,
M.D.
and DAVID PATON, M.D. Baltimore, Maryland
A new surgical illuminator, described here, offers several useful advantages : ( 1 ) It is adjustable by the surgeon; (2) it pro vides a source of intense cool light; (3) it is compact and portable; and (4) it is rela tively inexpensive. The illuminator, which weighs 3.5 pounds, is mounted on a balanced arm with a multi ple-movement joint that permits a wide range of positions so the light can be di rected toward the surgical field from almost any angle (fig. 1). The housing of the illu minating system is a truncated pyramidal body with multiple vents at the base and apex to permit air flow past the incandescent lamp by means of an induction-type, sparkfree electric motor mounted within the hous ing. The motor drives a reverse-action blade, thereby drawing air from the area of the surgical field into the housing system and di recting it away through the distal end of the lamp toward the ceiling. A door on one side of the housing permits access to the incandescent lamp for replace ment. The source of light is a standard 100watt projection lamp with a bayonet-type socket. The life span of the incandescent lamp is rated between 80 and 100 hours of continuous use. The illuminator's optical system is com posed of a parabolic mirror behind the incan descent bulb, and four condensing lenses. From The Wilmer Surgical Research Labora tory, The Wilmer Institute, The Johns Hopkins Hospital, Baltimore, Maryland 2120S. Reprint requests to David Paton, M.D., The Wil mer Institute, The Johns Hopkins Hospital, Balti more, Maryland 21205. * Manufactured by the Luxo Lamp Corporation, Port Chester, New York 10573.
Fig. 1 (Martinez and Paton). Surgical illumina tor shown here has an arm and bracket for table mounting. ( A ) Methyl methacrylate rod. ( B ) Lamp housing. (C) Spring-balance flexible arm.
The lens nearest to the lamp is made of a heat-absorbing glass; two other lenses are contained within the housing. The fourth component of the optical sys tem attaches to the illumination housing and is an eight-inch, removable methyl methacry late rod with a diameter of 1.25 inches. The rod fits into the instrument housing by means of its aluminum collar, permitting a bayonet connection on the undersurface of the metal housing. This rod, which has a 12diopter refractive power, not only completes the optical system but serves as a handle to position the illuminator in any direction the surgeon desires. The rod also helps protect the surgical field from the heat of the incan descent lamp. The lamp itself is mounted on the stan dard self-balancing arm used by the manu facturer for a variety of desk and hospital
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lamps. The arm can be mounted to a ceiling fixture, a wall bracket, a stand with wheels, or to a table in the operating room. The illuminator is turned on and off by a mercury switch contained within the lamp housing so that when the methyl methacrylate rod is directed above the horizontal the lamp is automatically turned off, and it is turned on again when the bar is brought to ward the vertical position in which it is used. The output of light at the best focal length of the light beam is in a range between 2000 and 3000 footcandles. As shown in Figure 1, the illuminator's optical system provides a strong central cone of illumination and a less intense area outside of the surgical field it self. The influence of the light beam on the surgical field is only 1°C over ambient tem perature. The plastic rod can be sterilized in any cold nonalcoholic sterilizing solution such as benzalkonium chloride (Zephiran) 1 : 5000 aqueous solution, or thimerosal (Merthiolate) 1:500 aqueous solution. Clinical evaluation of this surgical illumi nator at The Wilmer Institute has led to very satisfactory conclusions. One illumina tor alone is entirely sufficient as a light source for any ocular procedure. To mini mize adjustments of the light during sur gery, two illuminators can be used in tandem
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with only occasional adjustments by the sur geon to avoid reflections or glare or to change the angle of illumination, as for ex ample during dacryocystorhinostomy. Be cause the heat produced by this illumination system is negligible, there is no drying of the ocular itssues, in contradistinction to that caused by the traditional overhead illumina tors commonly employed in operating rooms. Also, compared to such light sources the cost of obtaining and operating this surgical illu minator is impressively low. Although this instrument has been devel oped chiefly for ophthalmic surgery, numer ous other clinical and research uses have also become apparent. SUMMARY A new surgical illuminator, with a high intensity, cool, and easily adjusted light source, is reported. Its features include a de tachable Lucite rod, which not only serves as a portion of the optical system, but also (when sterilized) can be used by the surgeon for adjusting the angle of illumination. There is a mercury switch for turning off the lamp by directing the rod above the horizontal plane, and the lamp has a flexible arm for maintaining the illuminator's position. The arm can be mounted on a wall, table, or ceil ing bracket.