Surgical lighting is one of the most critical factors in the operating room. Effective lighting is essential to illuminate the surgical site and provide surgeons with a clear view. This not only enhances the quality and precision of surgical procedures, but also increases patient safety, improves turnaround times, and reduces the risk of complications and malpractice claims.
The optimum lighting method depends on the type of surgery being performed and the surgical site, with the main options being overhead lights and headlamps. Overhead lights are typically used during open surgery – where the surgical site is more easily accessible – and LED light sources are increasingly being used in this application. These lights can be ceiling-mounted, wall-mounted or free standing, with mobile standalone lamps being frequently used for examination purposes. One downside of overhead lights is that they may not illuminate the surgical site precisely, creating a diffused light pattern with insufficient illumination in some areas, while flooding other areas of the cavity with too much light, leading to bleaching of colors.
Wearable headlamps are now widely used in a theatre setting, and are particularly useful for deep, lateral and narrow surgical sites, as they provide bright and targeted light spots, reducing shadowing. They can be battery-powered or plugged into an external electricity source. Unfortunately, headlamps can be uncomfortable to wear, and may cause head and neck pain after long periods of use, potentially resulting in chronic musculoskeletal conditions in the long term. In addition, external cables can limit movement and become a trip hazard in an already busy environment.
With so many surgical lighting systems out there, it is difficult to decide which would be best for your specific application. In this article, we discuss the top 10 most important factors to consider when choosing and setting up your surgical lighting, as well as how a novel in vivo lighting solution –KLARO™ – could alleviate many of the problems surgeons face on a daily basis.
1. Color Quality
Color temperature and color rendition index (CRI) are two critical considerations for surgical lighting that affect the light output quality. Color temperature refers to the relative warmth of the light tone, whereas the CRI describes how well the light allows subtle distinctions in the natural colors of an object to be visualized. Additionally, the lighting industry has developed a special measurement called the R9 to define how well a light source renders deep, saturated red, which is the most critical color for surgical procedures.
Bright white light is usually not the best type of light for surgery, as it bleaches everything, removing the subtle differences in tone and texture that surgeons rely on to distinguish tissue and tumor boundaries. You should aim choose a product with a correlated color temperature (CCT) between 3500 K and 6700 K, and a CRI of over 80, in order to provide optimal tissue color rendition. The R9 value of your lighting choice should also be above 70, making the red tones appear bolder and more vivid. Using a light with the wrong CCT, CRI or R9 values could make accurate tissue identification far more difficult, for example when delineating tumor margins, and this could potentially lead to errors and delays in surgery.
2. Adjustable Brightness
Overly bright light can introduce glare, and may reflect off polished metal instruments, tables and machinery. This impedes tissue and contrast visualization, and can result in strain, fatigue and permanent damage to the surgeon's eyes. Since tissues and organs absorb a great deal of light, and also possess poor reflective qualities, surgical lights need to provide enough illumination to allow for accurate depth perception. Choosing a product that can provide intense glare- and shadow-free light is absolutely essential. In addition, the brightness of surgical lights should be adjustable to the needs of each procedure, and to the personal preferences of individual surgeons. For instance, surgeries in deep cavities, such as in the thoracic or abdominal spaces, will typically require higher light intensities to achieve optimal visualization.
3. Shadow Management
Shadowing is inevitably caused by combination of overhead lighting and the surgical team leaning over the surgical site. It’s a key factor when considering lighting options, as it greatly affects the visualization of critical anatomy. There are two categories of shadows, namely contour shadows and contrast shadows. Contour shadows can sometimes help with depth perception in deep surgical cavities, but contrast shadows can be a significant hindrance to high precision tasks during open surgery. This can result in the need for constant readjustment of both lighting and surgical instruments, disrupting and delaying the procedure. This is especially relevant for operations taking place in small and deep cavities, such as oral, liver and gynecological surgeries. Shadows also cause eye strain and fatigue for operating staff, and minimizing unhelpful shadowing is one of the most frequently suggested improvement cited by surgeons and nurses alike.1 There is clearly a trade-off between good anatomical visualization and good depth perception, which requires a delicate balance of illumination and shadow contrast.
4. Targeted Lighting
There is an increasing preference towards smaller surgical incisions, due to the associated faster patient recovery times, but around 88 % of surgeons find it difficult to illuminate deep and narrow surgical cavities with current lighting solutions. In a study of surgeons in low-resource settings, an incredible 80 % reported that the quality of their surgical lights represented a patient safety risk, and 18 % confirmed that they had witnessed a negative impact on patient outcomes because of inadequate lighting.2 In addition to this, medical staff may experience visual discomfort when unnecessary areas inside the operating field are illuminated.
Existing surgical lighting systems have a fixed shape illumination pattern, whereas the wound and surroundings have variable shapes and characteristics. A lighting system that is able to adapt its shape and light distribution to the characteristics of the wound can improve visual performance and reduce the negative impacts for patients and staff. Look for lighting systems that are suitable for the type of surgery you perform, and consider investing in a variety of lighting types to cater for a range of surgical cavities and procedures.
With headlamps, it is often necessary for medical staff to work in uncomfortable and awkward positions for prolonged periods to direct the light to the target site. This is bad for their posture, and contributes to musculoskeletal disorders in the long term. Notably, 68 % of surgeons who frequently use headlamps experience neck pain,7 as well as fatigue, back pain and headaches. On top of this, headlamps only allow the user themselves to see effectively at any one time, and the other team members’ visibility of the surgical site will be dependent on the user's movement.
When selecting lighting, it is key to train practitioners in proper posture and equipment use. Headlamps should be comfortable and lightweight enough to be worn for long periods of time. These precautions should reduce the likelihood of musculoskeletal strain for surgical staff across multiple specialties.
6. Heat Management
All types of high-intensity surgical lighting equipment under constant use will radiate heat, with some headlamps reaching in excess of 44 °C.3 This creates a burn and fire risk, with numerous incidences of cutaneous burns and operating room fires being reported due to lighting equipment.4,5,6 Heat from lighting can also dry out and damage highly sensitive exposed tissues, as well as causing health concerns for surgical staff, who are exposed to hot lights and while wearing PPE for much of their day. When setting up lighting in the operating room, it’s important to consider the maximum temperature that your equipment can reach, and to use low-heat options where possible. It is also good practice to avoid prolonged skin exposure to high-intensity lighting during surgery, and to keep equipment that radiates heat away from the surgical cavity wherever possible.
Around 64 % of surgeries are disrupted by the need to frequently reposition the lights,5 and this causes distractions, delays and stress to the medical team. This problem is exacerbated in surgeries that take place at complicated angles, such as gynecological procedures or when it is necessary to work under a flap of tissue. Often a dedicated member of staff is needed simply for readjusting the light, adding to the medical center’s financial costs. It is vital to arrange lighting well at the beginning of the procedure to avoid the need for repositioning it throughout, and if possible, to choose equipment that is quickly and easily adjustable by the surgeon themselves, cutting down disruptions and eliminating the need for additional staff members.
8. Infection Control
Reusable instruments, including lighted retractors and light cords, require a high degree of decontamination and sterilization after use to ensure that biological materials from one patient do not come into contact with the next. However, studies indicate that decontamination processes might not be consistently adhered to, and may not be 100 % effective, resulting in significant risk of cross-contamination between patients undergoing surgery. One investigation found that 29.5 % of samples from reusable devices still tested bacteriologically positive even after sterilization,8 a concerning statistic as incomplete decontamination represents a substantial clinical risk for patients. It has been found that the introduction of disposable instruments drastically decreases the risk of pathogen growth and transfer, reducing patient infection rates by 66 % and improving postoperative outcomes.9
Lighting choices can have an impact on surgical site infection (SSI) rates and patient recovery, leading to repercussions for healthcare providers in terms of patient turnaround and surgical costs. In particular, the heat from surgical lighting can interfere with the precise laminar airflow needed in the OR to decrease bacteria circulating within the surgical field. Higher temperatures lead to a higher risk of the patient contracting an infection from these bacteria during their surgery. In addition, the larger the incision, the higher the risk of infection. Choosing a lighting solution that offers good visibility of the surgical site without requiring the incision size to be increased both improves infection control and promotes faster recovery times.
Sterilizing reusable light sources such as lighted retractors can be very time-consuming and costly, and the instruments need to be regularly maintained and stored on-site when not in use, representing significant financial outlays for already stretched healthcare providers. In addition, there can be secondary costs associated with their use, such as delayed operations due to equipment shortages, and patient complications and malpractice claims due to cross-contamination.10 Studies have shown that disposables equipment is in fact cheaper overall for hospitals,11 as well as more sanitary, so it is no wonder that single-use products are often preferred by surgical staff over reusable ones. The ease and speed of sanitization to prevent cross-contamination between patients, as well as the ancillary costs, are important factors to consider when deciding whether to purchase reusable or disposable lighting equipment.
10. Portability and Access
Surgical lighting needs to be plugged into an external power supply or light source, such as a fiber optic cable, potentially restricting movement and causing surgeons to stand in uncomfortable positions for long periods of time. Awkward positioning of lights can hinder mobility and access to the surgical site, prolonging surgery times and increasing the risk of errors. The copious wires found in operating theatres are also tripping hazards, and there is a constant need to reduce the volume of cables to enhance staff safety.
Medical personnel need to be able to move freely and safely around the operating table, both for their own comfort and to perform procedures accurately and efficiently. Ideally, lighting solutions should be portable and lightweight, independent of individual staff members, minimize obstruction to movement, cut down the number of cables in the room, and reduce the time needed to set up the room for each surgery.
Is in vivo lighting the solution?
Vivo Surgical, SingHealth and Panasonic Lighting (Europe) have teamed up to develop an innovative in vivo LED lighting device to overcome the current shortcomings of surgical lighting. KLARO™ is a sterile, single-use flexible LED light strip that illuminates surgical cavities from the inside. Offering up to four hours of use, this new tool floods small surgical sites with light, avoiding shadows from external lighting and providing wide-angle illumination exactly where it is needed. What’s more, its compact size and targeted lighting allows for smaller incisions, lowering the risk of infection and complications for the patient and, in turn, speeding up recovery and discharge times. Since it is disposable, KLARO™ does not require sterilization after use, and so reduces the workflow and financial costs for hospital staff. This has a huge benefit for both patient turnaround times and for meeting tight budgets.
Professor N Gopalakrishna Iyer, Head of the Department of Head and Neck Surgery at the National Cancer Centre Singapore and Singapore General Hospital, was a key contributor to this project and highlighted some of the advantages of this new product over other surgical lighting options: “KLARO™ offers varying light intensities, which allows the surgeon to choose the optimal light intensity based on their own preferences and the size of the space that they are illuminating. In addition, the advanced LED technology maintains a safe operating temperature of below 38 °C regardless of light intensity – making the system perfect for in vivo use.”
KLARO™ is lightweight, hands-free and wireless, increasing staff comfort, mobility and safety in the operating theatre. It does not rely on any external power source, so it is also a failsafe option for surgical procedures taking place in areas with unreliable electricity supplies and a risk of power cuts, such as developing countries, and conflict and disaster zones.
Dr Gopal explained how the versatile KLARO™ light is making high quality surgical lighting more accessible: “The system is self-contained; its four-hour battery pack can be easily attached to surgical drapes or placed next to the patient, meaning that the surgeon is free to move without having to traipse a lighting source around the theatre. This also means that surgeons can take KLARO™ into any operating suite, regardless of the resources that are already there, and know that they will be equipped with sufficient and safe illumination, bringing equality to surgical lighting everywhere.”
Conventional surgical lights have barely changed over the last 100 years, failing to keep pace with the rapid developments in medical devices and procedures over recent decades. The innovative and adaptable KLARO™ light strip finally provides a 21st century solution for 21st-century surgery. In vivo lighting enables illumination deep inside surgical cavities, and can be particularly useful where overhead lights or headlamps are not adequate or practical. This type of light source can be attached to a surgical instrument or to drapes or supports outside of the sterile field or used in combination with other light sources to increase visibility. In vivo lighting also allows for smaller incisions to be made while still providing enough light to effectively visualize the area, leading to faster recovery times and fewer complications.
Knulst, AJ et al. 2011 . Indicating shortcomings in surgical lighting systems. Minim Invasive Ther Allied Technol. 20(5):267-75. https://doi.org/10.3109/13645706.2010.534169. Epub 2010 Nov 17. PMID: 21082904.
Forrester, JA et al. 2017. Impact of Surgical Lighting on Intraoperative Safety in Low-Resource Settings: A Cross-Sectional Survey of Surgical Providers. World J Surg. 41(12):3055-3065. doi: 10.1007/s00268-017-4293-z. PMID: 29051968.
Tuggle, DE and Smith, K. 2010. Cutaneous burns from a surgical headlight beam: a case report, review of the literature, and evaluation of surface temperature at different working lengths from surgical headlights. J Oral Maxillofac Surg. 68(1):176-8. doi:10.1016/j.joms.2009.04.058. PMID: 20006173.
Bourke, DL et al. 1993. Severe burn caused by an operating room light. Anesthesiology 79(1):171-173. doi: 10.1097/00000542-199307000-00023. PMID: 8342802.
de Armendi, AJ et al. 2010. Headlight with fiber-optic xenon light source may cause harm to patients. Am J Otolaryngol. 31(1):57-8. doi: 10.1016/j.amjoto.2008.08.012. Epub 2009 Mar 6. PMID: 19944902.
Hensman, C et al. 1998. Total radiated power, infrared output, and heat generation by cold light sources at the distal end of endoscopes and fiber optic bundle of light cables. Surg Endosc.12(4):335-337. doi: 10.1007/s004649900665. PMID: 9543524.
Sahni, D et al. 2015. Is there an Increased Incidence of Cervical Degenerative Disease in Surgeons who use Loupes and a Headlight? J Spine. 4: 256. doi:10.4172/2165-7939.1000256.
Srejic E. 2016. Reusables, disposables each play a role in preventing cross-contamination. Infection control today.
Mager, R et al. 2018. Clinical outcomes and costs of reusable and single-use flexible ureterorenoscopes: a prospective cohort study. Urolithiasis. 46(06):587–593.
Curlin, J and Herman, C. K. 2020. Current State of Surgical Lighting. Surgery journal 6(2):e87–e97.
Mont, M A et al. 2013. Single-use instrumentation, cutting blocks, and trials decrease contamination during total knee arthroplasty: a prospective comparison of navigated and nonnavigated cases. J Knee Surg 26(4):285-90.