Role Of Ultraviolet C in Orthopedics
Maintaining quality of life for our ageing population increasingly involves provision of surgical solutions to ease discomfort and impaired mobility associated with musculoskeletal degenerative disorders. Although rates vary considerably between nations, increasing numbers of hip and knee replacements are being undertaken in most countries. As such, management of this demand and minimizing risk of complication, including infection, are ever more pressing.
SSIs following clean orthopedic procedures, such as joint replacement and certain spinal procedures, have become increasingly rare since evidence-based practices related to skin preparation, surgical technique, and antibiotic prophylaxis have become the accepted standard of care in orthopedic surgery. However, the adverse outcome of SSIs related to a clean orthopedic surgical procedure continues to be associated with significant morbidity, cost, and even mortality. The patient’s functional status may also be adversely affected by an orthopedic SSI. Cost of revision of a total joint due to infection is 2.8 times higher than cost of revision for aseptic loosening, and 4.8 times higher than costs associated with primary total hip arthroplasty.
Contamination of the surgical wound is almost unavoidable despite the best efforts of the surgical team. The goal in surgical antisepsis is minimization of the bacterial load to the greatest degree possible. Lack of adherence to asepsis by scrubbed personnel or those in close proximity to the sterile field can be a risk factor for development of an SSI. Quantitatively, it has been shown that if a surgical site is contaminated with >105 (100,000) microorganisms per gram of tissue, the risk of SSI is markedly increased. However, the dose of contaminating microorganisms required to produce infection may be much lower when foreign material (i.e.,implants or sutures) is present at the site (i.e., 102 or 100 microorganisms per gram of tissue).
Preparation of the patient’s skin is a significant intervention taken to reduce bacterial contamination. However, since as much as 20% of the skin’s bacteria are resident (living beneath the epidermal layer of skin, in appendages such as hair follicles and sebaceous glands), any incision made through the skin has the potential of carrying some of this bacterial load directly to the operative site.
Evidence based guidelines for decreasing surgical site infection.
Preoperative shaving of the surgical site the night before an operation is associated with a significantly higher SSI risk than other methods of hair removal or no hair removal at all.
Preoperative Skin Preparation
Chlor Hexidine Gluconate is better disinfectant than iodophor based solutions. A rinse-free cloth has been introduced as an alternative to Chlor Hexidine Gluconate showers, and some data suggests ease of use and improved patient compliance as well as reduced rates of SSI. One advantage of the cloth is that CHG is allowed to remain on the skin rather than being washed off.
Preoperative screening for S. aureus and then cleansing with Chlorhexidine Gluconate and intranasal mupirocin were effective in preventing SSI.
The results of a randomized, double-blind, placebo-controlled trial published in January 2010 in the New England Journal of Medicine in clean-contaminated surgery identified Chlorhexidine Gluconate with alcohol as superior to iodoform-based compounds.
A Cochrane review found alcohol-based rubs to be as effective as aqueous solutions hand wash for preventing SSIs in patients. Other investigators reported that the use of scrub brushes during hand wash had no positive effect on asepsis and may actually increase the risk of infection as a result of skin damage.
Other Intraoperative Factors
The most common method by which bacteria can gain access into a wound is when the wound is open during the intraoperative period. The quality of air entering the OR should be carefully controlled. Operating room air may contain microbial-laden dust, lint, skin squames, or respiratory droplets. The risk of contamination can be minimized by providing consistent adequate air flow.
Laminar air flow refers to systems that produce little or no turbulence. It is not clear that these measures are essential. As an example, prospective and controlled studies demonstrated a decrease in rates of surgical site infections in total hip and knee prosthesis procedures when laminar airflow technology was used. However, the value and cost-effectiveness of laminar airflow is questionable when surgery occurs in modern facilities that have high rates of air exchange and antimicrobial prophylaxis is given.
We have all felt the power of UV after spending a summer day outdoors. The sun is a powerful source of UV energy; even the slightest overexposure gives us a sunburn. Continued overexposure to UV energy can be quite harmful, but the UV spectrum offers many beneficial characteristics as well. With the right control and application UV energy can be used for UV disinfection of water, purify air and surfaces, cure adhesives and coatings and sterilize tools, just to name a few.
Ultraviolet Germicidal UVC reduce the threat of microbiological contamination of the surgical wound during orthopedic surgeries by continuously disinfecting the wound surface, and the environment around the patient. Postsurgical infection rates, including healthcare associated infections (also known as hospital acquired infections), can be reduced significantly
Studies as far back as 1937 (Duke University, Durham, North Carolina), and as recent as 2007 (Center for Hip and Knee Surgery, St. Francis Hospital-Mooresville, Mooresville, Indiana) report the effectiveness of ultraviolet light in reducing overall post-surgical infection rates. In the Duke study, during the first five years of use, overall infection rates on clean cases showed a significant decrease from 10% to 0.24%; on the orthopedic service, a decrease from 16.5% to 0.75% was reported. For the next 26 years, the overall infection rate was reduced to 0.34%
The St. Francis study (July 1986 to July 2005) shows the infection rate in operating rooms decreased significantly, from 1.77% to 0.57%, when UVC light was used, even when laminar airflow was eliminated. Furthermore, the decrease in the infection rate for total knee replacements was also significant, from 2.2% to 0.5% (p <0.0001).
With the already extraordinary, and still increasing, cost of infections (including hospitalization, physician care, nurses’ salary, hospital insurance, loss of income from patient’s job, death benefits in case of death, and the like), it’s obvious that reducing infection rates is extremely important.
Early Studies on UV lights though reduced infection rates it was not widely accepted as the risk involved to personnel because of harmful UV A and UV B. Recently with Development of UV C specific gemicidal lights the interest has again raised also the healing ability of UV rays adds on to the benefit of patient.
The sun emits ultraviolet radiation in the UVA, UVB and UVC bands, but because of absorption in the atmosphere, 98.7% of the ultraviolet radiation that reaches the Earth’s surface is UVA. Ordinary glass is partially transparent to UVA but blocks UVB and UVC. This feature gives sunglasses and eye wear UV protection capabilities. A positive effect of human UVB exposure is that it induces the production of vitamin D in the skin.
UVC rays are the highest energy form of ultraviolet light. Since UVC rays are filtered by the Earth’s atmosphere, organisms have not developed a natural defense against UVC energy. When the DNA of a microorganism absorbs UVC energy, molecular instability occurs resulting in the disruption of the DNA sequence. This renders the cell unable to grow or reproduce. Without the ability to reproduce the cell cannot infect and it rapidly dies.
The application of UVC energy to inactivate microorganisms is known as Germicidal Irradiation or UVGI. It has been used for this purpose since the early nineteen hundreds. Artificial UVC energy is produced in germicidal ultraviolet lamps which produce UV radiation by ionizing low pressure mercury vapor. These lamps are similar to typical fluorescent household lighting fixtures but do not have the phosphorescent coating which imparts the soft white light. Ionized mercury emits a predominately discreet wavelength of 254nm – in the UVC band and, as it happens, is an ideal wavelength for disrupting the DNA of microorganisms.
Room disinfection is another growing area for UVGI technology. UV systems have been developed to effectively destroy microorganisms such as mold, viruses and bacteria and to do so relatively quickly. For example, a typical hospital patient room requires thorough manual cleaning before the next occupant is admitted. The turn around time needs to be minimal but cleaning must also be effective. UVGI units such as the Mobile Room Sanitizer can disinfect a typical patient room in under 5 minutes.
Recently UV C has been implicated in promoting wound healing.
Various commercial hand held devices have also come up for easier use.
The current guideline is exposure of surgical site and Implant to UVC for 30 sec prior to wound closure, it can significantly reduce incidence of Surgical site infection.
Also it is one of the most cost effective way for control of wound infection. It not only reduces antibiotic consumption but also prevents development of antibiotic resistance organisms in community.