# Surgical Headlamp- please help



## nsurgdoc (Jun 19, 2015)

Hey everyone,

I'm a neurosurgery resident at university of virginia and I was hoping someone here with more knowledge than I could help me out. I really want/need to build a surgical headlamp. I know this has been discussed before: http://www.candlepowerforums.com/vb/showthread.php?290476-Worm-light-(SST-90-headlamp) for example, however it's been 5 years now and there's been a lot of advances in technology. 

Currently I'm using a headlamp like this one: http://www.integralife.com/index.as...tec%AE&ProductLineID=174&PA=Surgical-Lighting. The problem is, it sucks being tied down to light box thats plugged into an outlet. It gets in the way especially when operating with other people plugged into their own light boxes. Ideally I would have a battery strapped to my waist. 

For anyone thats still interested in helping out, the ideal light would be super bright (as bright as possible, >2000 lumens), with as natural a white light as possible, adjustible light diameter, last on a charge all day without dimming, not be heavy, and not get hot. I was thinking an ultra efficient LED bulb(s) connected with a lithium polymer battery of some sort would do the trick, but was hoping I could get some suggestions from everybody here. 

Thanks,

Dom


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## Amelia (Jun 19, 2015)

The main problem with your request is the Lumens spec - there are VERY few, if any, stock headlamps available with 2000+ lumens output. More realistic would be something in the 700-1000 lumens range, of which there are quite a few to choose from.

My recommendation would be the Zebralight H600w or H600Fw (or maybe the H602w, if you want pure flood with no "hot spot"), all of which fall into the 950-ish lumen range. Nice neutral white output, long runtime, and reasonable weight. The H600w will have the most "throw" and defined "hot spot" zone, which might be a problem in surgery where (I'm assuming) you would want even, smooth lighting.


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## Eagles1181 (Jun 19, 2015)

Please don't take this wrong, but have you ever worked with a 2000 lumen light? I know you need bright, but my 1000 lumen pocket light bounced off my hand at arms distance will make me see spots for a short time. 

Check out the Fenix HP30. It will give you 500 lumen for almost 4 hours. Or if you can work with 200 lumen (which is still fairly bright, but might not be bright enough) which will last for a full 12 hours. Also I don't know if changing batteries in the OR is possible (clean environment and all) but dropping in fresh batteries takes less than 1 minute.


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## nsurgdoc (Jun 19, 2015)

Amelia said:


> The main problem with your request is the Lumens spec - there are VERY few, if any, stock headlamps available with 2000+ lumens output. More realistic would be something in the 700-1000 lumens range, of which there are quite a few to choose from.
> 
> My recommendation would be the Zebralight H600w or H600Fw (or maybe the H602w, if you want pure flood with no "hot spot"), all of which fall into the 950-ish lumen range. Nice neutral white output, long runtime, and reasonable weight. The H600w will have the most "throw" and defined "hot spot" zone, which might be a problem in surgery where (I'm assuming) you would want even, smooth lighting.



Hey thanks for your input. I realize that there's few stock headlamps available, but I just know there's a way to build it. Check out this website that I found: http://www.enovaillumination.com/pages/cyclops-xlt-225. I think this is pretty much what I described but I have a feeling that there's other LED bulbs that people know about on this site to create something that is more powerful and could potentially last much longer than this one.


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## nsurgdoc (Jun 19, 2015)

Eagles1181 said:


> Please don't take this wrong, but have you ever worked with a 2000 lumen light? I know you need bright, but my 1000 lumen pocket light bounced off my hand at arms distance will make me see spots for a short time.
> 
> Check out the Fenix HP30. It will give you 500 lumen for almost 4 hours. Or if you can work with 200 lumen (which is still fairly bright, but might not be bright enough) which will last for a full 12 hours. Also I don't know if changing batteries in the OR is possible (clean environment and all) but dropping in fresh batteries takes less than 1 minute.



I'm not sure the amount of lumens the surgical headlights use, but I think it's at least 2000. They're all measured in lux, and are about 150,000. Given a one diameter circle of illumination at 2.5 feet, it's a pretty high conversion to lumen. Having said that, I'm sure there's an LED light that can generate that type of illumination. I replied to eagles earlier with a link of a surgical headlamp that uses an LED: http://www.enovaillumination.com/pages/cyclops-xlt-225. I have a feeling this product's using a bulb that is not astronomically powerful or expensive if bought on its own.


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## Lynx_Arc (Jun 20, 2015)

I'm thinking realistically you need about 20 watts of power as I'm guessing LEDs powerful enough to do what you want to are going to give you about 100 lumens/watt efficiency and if that were to be for 8 hours that would be 160 watt hours of power and the most efficient battery gets you about 10 watts for an 18650 meaning you need 16 of them in a battery pack to drive your LED light.


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## Mr Floppy (Jun 20, 2015)

The market is catered for by a number of specialist providers, usually purchased/leased by the hospital. I've never heard of a surgeon having to bring in their own gear, but if that is the way your medical system works...

Better make sure it can take the disinfectant


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## Mooreshire (Jun 22, 2015)

That headlamp your school has you using is almost assuredly autoclave compatible, in other words the head and fiber optic cable can be sterilized in a high pressure steam cleaning machine without being damaged. The box it plugs into produces a massive amount (300 high-pressure-gas-bulb Watts) of light with the most accurate color rendering properties available. If it's anything like the surgical headlamp in my collection (I collect headlamps) the lamp's optics produce a perfectly smooth beam with no light artifacts (like brightness or color variations) and it features precisely controllable zoom and position adjustments. In order to comply with these requirements high-end surgical headlamps cost a thousand dollars or more new. Absolutely no consumer grade headlamps will meet these requirements. If you've got the skills to manufacture surgical headlamps then you should consider switching careers and designing medical devices instead of repairing brains. 

If a neurosurgeon walked into an operating room with a headlamp that wasn't properly sterilizable, couldn't render colors correctly, and couldn't be focused so as to only illuminate the surgical site (with minimal glare from surrounding tissue)... I'm inclined to hope they would promptly be escorted back out of the OR. I'm usually all for DIY, but perhaps not when it comes to cranial healthcare. I'm just a headlamp nut though, so you should chat with your college's technicians for a more informed opinion - but an engineer buddy of mine who works for a company that makes surgical equipment describes the process of getting a device certified for use in an operating theater as being on par with getting a piece of gear certified to fly to the space station.


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## Dubois (Jun 22, 2015)

Excellent response.


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## nsurgdoc (Jun 22, 2015)

Mooreshire said:


> That headlamp your school has you using is almost assuredly autoclave compatible, in other words the head and fiber optic cable can be sterilized in a high pressure steam cleaning machine without being damaged. The box it plugs into produces a massive amount (300 high-pressure-gas-bulb Watts) of light with the most accurate color rendering properties available. If it's anything like the surgical headlamp in my collection (I collect headlamps) the lamp's optics produce a perfectly smooth beam with no light artifacts (like brightness or color variations) and it features precisely controllable zoom and position adjustments. In order to comply with these requirements high-end surgical headlamps cost a thousand dollars or more new. Absolutely no consumer grade headlamps will meet these requirements. If you've got the skills to manufacture surgical headlamps then you should consider switching careers and designing medical devices instead of repairing brains.
> 
> If a neurosurgeon walked into an operating room with a headlamp that wasn't properly sterilizable, couldn't render colors correctly, and couldn't be focused so as to only illuminate the surgical site (with minimal glare from surrounding tissue)... I'm inclined to hope they would promptly be escorted back out of the OR. I'm usually all for DIY, but perhaps not when it comes to cranial healthcare. I'm just a headlamp nut though, so you should chat with your college's technicians for a more informed opinion - but an engineer buddy of mine who works for a company that makes surgical equipment describes the process of getting a device certified for use in an operating theater as being on par with getting a piece of gear certified to fly to the space station.



Hey Mooreshire,

Thanks for replying. I know this is a huge undertaking, but there's a couple things that give me reason to think it can be done. First of all the headlamp does not need to be sterilizable. It's never sterile and does not need to be sterile. It never touches the patient, and never touches the sterile parts of our garb or setup. But I agree with everything else you mention. They do have to have an adjustable focus, which I think just changes the aperature. And the color in general i think is set at ~1600K or so, which is the whitest light that gives the best color rendering. The light doesn't need FDA approval to in order to be used in the OR. Just like when we wear "loupes" which are basically mini telescopes attached to glasses- do not need approval either since they do not touch the patient.


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## nsurgdoc (Jun 22, 2015)

Lynx_Arc said:


> I'm thinking realistically you need about 20 watts of power as I'm guessing LEDs powerful enough to do what you want to are going to give you about 100 lumens/watt efficiency and if that were to be for 8 hours that would be 160 watt hours of power and the most efficient battery gets you about 10 watts for an 18650 meaning you need 16 of them in a battery pack to drive your LED light.



Hey Lynx, 

This is great stuff. Do you know of an LED with that type of efficiency that is relatively small/light? That can be realistically used as a headlamp? I was thinking maybe a Nichia high-power LED? Maybe one like this one: http://www.leds.de/en/High-Power-LE...-LED-Array-BXRA-30G7000-warmwhite-6600lm.html . Not sure if this would overheat instantly or not.

Thanks for going with my craziness.


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## Mooreshire (Jun 23, 2015)

nsurgdoc said:


> Hey Mooreshire,
> 
> Thanks for replying. I know this is a huge undertaking, but there's a couple things that give me reason to think it can be done. First of all the headlamp does not need to be sterilizable. It's never sterile and does not need to be sterile. It never touches the patient, and never touches the sterile parts of our garb or setup. But I agree with everything else you mention. They do have to have an adjustable focus, which I think just changes the aperature. And the color in general i think is set at ~1600K or so, which is the whitest light that gives the best color rendering. The light doesn't need FDA approval to in order to be used in the OR. Just like when we wear "loupes" which are basically mini telescopes attached to glasses- do not need approval either since they do not touch the patient.



I'm excited about your project! I'm also glad to hear that it won't have to comply with any sort of certification process. Perhaps the lamp in my collection was intended for messier work or some such, as it is constructed out of surgical materials like titanium and ultra-high-molecular-weight polyethylene. Its zoom is the very same sort of sliding aspheric TIR optic arrangement found in many flashlights, but it's a step above any optic I've seen in a flashlight in terms of its beam's smoothness and sharp boarder with complete lack of spill. Its head is also very narrow (25mm at its widest), so that it doesn't obscure your vision when positioned between your eyes (for true coaxiality when peering into shadowy incisions) like that Cyclops XLT 225 model's fatter looking head seems it would. I have seen medical headlamps (on a dentist and their assistant, if I'm recalling correctly) which didn't look totally sterilizable but which had their heads wrapped in some sort of disposable plastic - that would be a good cleanliness solution for when you needed to reach up to adjust the angle or zoom (I know you said it never touches your garb but how do you adjust it sans hands?). Unfortunately a plastic wrap would keep a hot diode from getting the air circulation it needs to keep from overheating.

The diode you inquired about is 51mm wide on its bare board and would require a hefty hunk of heatsinking to dissipate the huge amount of heat it produces (literally an 85 watt space heater on your head) - and that heat would then be dissipated right onto your face, whereas the hot bulb in the traditional design is off in its own box leaving only the relatively lightweight lens, fiber optic cable end, and tilt mechanism on your head. A compact 1000 lumen lamp might run at that brightness for an hour off of one common li-ion battery and barely add any sweat to my brow or weariness to my neck in the process, but if you wanted to run longer at double that apparent brightness (which would require 4000+ lumens) you would of course need a significantly larger battery pack to be guaranteed to last a full surgery at that output level and a way larger heatsink which would stress your brow and neck. If you can get the size of the head down to work sitting coaxial between your eyes and keep the heat output and weight/balance to within what you think you could comfortably wear for the length of time required then you could be good to go. I'd still run everything by your school's technicians of course.

Color accuracy and color temperature are independent; a perfect color rendering source can be any temp - the star we're closest to burns at 5800K, but different atmospheric conditions filter that to a wide variety of warmer color temperatures at the planet's surface but the color rendering accuracy of sunlight is never reduced. I do wonder if it will matter whether your headlamp's light properties match the other lights being used in the room, as light sources with different CRI/temps rarely seem to mix particularly well. For example, when examining (and photographing) minerals inside caves I prefer to have only my fancy custom Nichia219-powered lights trained on my subject, and when a companion wearing a different light looks over it usually seems to screw the colors and textures up - but my eyeballs can tell that my lamp (CRI:92) is still less color-accurate than sunlight (CRI:100) or even a medical-imaging-grade Ceramic Metal-Halide bulb (CRI:96). It is easier to have all your equipment take the same model CMH bulb than it is to find perfectly matching diodes, especially if those diodes will be shone through any sort of optics which could themselves alter the light properties. (Different optics alter different properties in different ways, such as refracting or shifting the color temperature or producing beam artifacts or uneven brightness.) If you're the only person trying to shine a light into the skull in question and a mismatched overhead light isn't an issue, then I doubt <10 CRI points or a different color temperature will make any practical difference.

I work as an imaging technician at a liberal arts and environmental sciences college designing illumination solutions for projects ranging from moviemaking to microscopy and I collect headlamps for fun because of my interests in the history of mining/caving/outdoorsmanship technologies and I know _absolutely nothing_ about surgical illumination. You should inquire around and try to find someone who has worked on designing surgical lamps and I'd bet they'll be excited to talk to you about the challenges you will encounter. Companies love getting inquiries from academics; email a few and I bet some enthusiastic PR person will get you in touch with an equally enthusiastic engineer.

Good luck with your project, and please do keep us updated! (Yeesh, I sure do love parentheticals don't I? lol!) Oh, and :welcome:!


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## eh4 (Jun 23, 2015)

"The diode you inquired about is 51mm wide on its bare board and would require a hefty hunk of heatsinking to dissipate the huge amount of heat it produces (literally an 85 watt space heater on your head) - and that heat would then be dissipated right onto your face, whereas the hot bulb in the traditional design is off in its own box leaving only the relatively lightweight lens, fiber optic cable end, and tilt mechanism on your head."

-Sounds like a job for a heat pipe.


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## TinderBox (UK) (Jun 23, 2015)

Anything that is going to be used in surgery needs to be able to be sterilized, I dont think you can get an flashlight that you can autoclave or boiled, you could use an liquid sterilizer like Milton tablets/liquid or the equivalent professional version to sterilizer it.

John.


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## SemiMan (Jun 23, 2015)

nsurgdoc said:


> I'm not sure the amount of lumens the surgical headlights use, but I think it's at least 2000. They're all measured in lux, and are about 150,000. Given a one diameter circle of illumination at 2.5 feet, it's a pretty high conversion to lumen. Having said that, I'm sure there's an LED light that can generate that type of illumination. I replied to eagles earlier with a link of a surgical headlamp that uses an LED: http://www.enovaillumination.com/pages/cyclops-xlt-225. I have a feeling this product's using a bulb that is not astronomically powerful or expensive if bought on its own.



Why not just get this one? There is a lot of work that goes into a product beyond just picking an LED. That is the easy part.

Is that CCT, 6500, typical for surgery now? I would have though something in the 4000-4500 would provide better gamut/rendering of tissue? Task lighting used to be halogen (driven very hard, so 3500+ CCT), so that would imply something in the 4000-4500 for LEDs would be suitable. I have never seen anything that high in a surgical light, generally 3500-5000K but have not looked in about 3-4 years.

I "whipped" up a headlight for a friend in the medical field about 5-6 years ago for field usage and mixed 3K and 6K for better gamut. It was also much brighter than anything out at the time. It used multiple reflectors with a bit of diffusion. It worked out well.


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## recDNA (Jun 23, 2015)

Mooreshire said:


> That headlamp your school has you using is almost assuredly autoclave compatible, in other words the head and fiber optic cable can be sterilized in a high pressure steam cleaning machine without being damaged. The box it plugs into produces a massive amount (300 high-pressure-gas-bulb Watts) of light with the most accurate color rendering properties available. If it's anything like the surgical headlamp in my collection (I collect headlamps) the lamp's optics produce a perfectly smooth beam with no light artifacts (like brightness or color variations) and it features precisely controllable zoom and position adjustments. In order to comply with these requirements high-end surgical headlamps cost a thousand dollars or more new. Absolutely no consumer grade headlamps will meet these requirements. If you've got the skills to manufacture surgical headlamps then you should consider switching careers and designing medical devices instead of repairing brains.
> 
> If a neurosurgeon walked into an operating room with a headlamp that wasn't properly sterilizable, couldn't render colors correctly, and couldn't be focused so as to only illuminate the surgical site (with minimal glare from surrounding tissue)... I'm inclined to hope they would promptly be escorted back out of the OR. I'm usually all for DIY, but perhaps not when it comes to cranial healthcare. I'm just a headlamp nut though, so you should chat with your college's technicians for a more informed opinion - but an engineer buddy of mine who works for a company that makes surgical equipment describes the process of getting a device certified for use in an operating theater as being on par with getting a piece of gear certified to fly to the space station.


I'm still amazed neurosurgeons use such bright illumination. I would think the reflection of over 2000 lumens would be blinding. I guess the bright lighting in the theatre helps the eye adjust to such bright lights...and several people wearing such headware all pointed at the same spot. Wow. That's a lot of light. Fascinating.


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## SemiMan (Jun 23, 2015)

recDNA said:


> I'm still amazed neurosurgeons use such bright illumination. I would think the reflection of over 2000 lumens would be blinding. I guess the bright lighting in the theatre helps the eye adjust to such bright lights...and several people wearing such headware all pointed at the same spot. Wow. That's a lot of light. Fascinating.



High amount of light creates highest pupil dilation resulting in best depth of field and focus.

High amount of light is also going to help with contrast ratio, signal to noise ratio, as long as you are not saturated, but sunlight is 100K lux, so there is a lot of potential range.


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## recDNA (Jun 23, 2015)

SemiMan said:


> High amount of light creates highest pupil dilation resulting in best depth of field and focus.
> 
> High amount of light is also going to help with contrast ratio, signal to noise ratio, as long as you are not saturated, but sunlight is 100K lux, so there is a lot of potential range.



More light makes the pupil contract not dilate.


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## Lynx_Arc (Jun 23, 2015)

nsurgdoc said:


> Hey Lynx,
> 
> This is great stuff. Do you know of an LED with that type of efficiency that is relatively small/light? That can be realistically used as a headlamp? I was thinking maybe a Nichia high-power LED? Maybe one like this one: http://www.leds.de/en/High-Power-LE...-LED-Array-BXRA-30G7000-warmwhite-6600lm.html . Not sure if this would overheat instantly or not.
> 
> Thanks for going with my craziness.



To get the kind of efficiency and long running time without burning your skull it may require multiple LEDs as at 2000 lumens output you are driving XM-L LEDs pretty hard efficiency probably is lower than that. Whatever the highest rated output you may want to run the LED at half to 2/3 of that for efficiency sake or end up adding more batteries in the mix. You would also need a pretty good heatsink. My advice is to research 18650 headlamp offerings on the market using XM-L2 and XP-G2 and other latest generation LEDs... perhaps even XPL LEDs as these headlamps have already done most of the homework for you with the exception of an external battery pack. It is possible that there is one on the market capable of such output with an external battery pack if that were so then you could just adapt it for more batteries perhaps by paralleling them in a similar designed pack.


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## recDNA (Jun 23, 2015)

Even if there is it won't have the zoom function and aim function.


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## SemiMan (Jun 23, 2015)

recDNA said:


> More light makes the pupil contract not dilate.



That's what I meant -)

Posted by really crappy Tapatalk app that is questionable wrt respect of personal data.


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## lampeDépêche (Jun 25, 2015)

I just want to echo Moorehead's comment here:

"I'm usually all for DIY, but perhaps not when it comes to cranial healthcare."

I think your plan to fabricate your own headlamp is ill-advised and irresponsible. Use a device that has been tested and approved.

And for god sakes, take sterilization more seriously.


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## broadgage (Jun 25, 2015)

Anything used in an operating theatre needs to be very clean, but that is not the same as sterile ! 
All sorts of sophisticated electronic gear is used in a modern operating theatre and it is maintained to a high degree of cleanness , but not sterilised by boiling or other means.

A headlight is worn on the surgeons head, which is not sterile and never can be. The surgeons head is of course rendered as clean as possible, and is partly covered by a sterile cap or other covering, but it cant be either completely covered nor be sterile.

I have seen headlights for surgery that work of a battery in a belt pack, they used a miniature metal halide reflector lamp made by Welch Allyn, a special low voltage DC ballast and a battery pack for IIRC 20 AA cells.
They are used by military surgeons in field hospitals when the lighting is of a lower standard than in a regular civilian hospital.


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## nsurgdoc (Jun 27, 2015)

Mooreshire said:


> I'm excited about your project! I'm also glad to hear that it won't have to comply with any sort of certification process. Perhaps the lamp in my collection was intended for messier work or some such, as it is constructed out of surgical materials like titanium and ultra-high-molecular-weight polyethylene. Its zoom is the very same sort of sliding aspheric TIR optic arrangement found in many flashlights, but it's a step above any optic I've seen in a flashlight in terms of its beam's smoothness and sharp boarder with complete lack of spill. Its head is also very narrow (25mm at its widest), so that it doesn't obscure your vision when positioned between your eyes (for true coaxiality when peering into shadowy incisions) like that Cyclops XLT 225 model's fatter looking head seems it would. I have seen medical headlamps (on a dentist and their assistant, if I'm recalling correctly) which didn't look totally sterilizable but which had their heads wrapped in some sort of disposable plastic - that would be a good cleanliness solution for when you needed to reach up to adjust the angle or zoom (I know you said it never touches your garb but how do you adjust it sans hands?). Unfortunately a plastic wrap would keep a hot diode from getting the air circulation it needs to keep from overheating.
> 
> The diode you inquired about is 51mm wide on its bare board and would require a hefty hunk of heatsinking to dissipate the huge amount of heat it produces (literally an 85 watt space heater on your head) - and that heat would then be dissipated right onto your face, whereas the hot bulb in the traditional design is off in its own box leaving only the relatively lightweight lens, fiber optic cable end, and tilt mechanism on your head. A compact 1000 lumen lamp might run at that brightness for an hour off of one common li-ion battery and barely add any sweat to my brow or weariness to my neck in the process, but if you wanted to run longer at double that apparent brightness (which would require 4000+ lumens) you would of course need a significantly larger battery pack to be guaranteed to last a full surgery at that output level and a way larger heatsink which would stress your brow and neck. If you can get the size of the head down to work sitting coaxial between your eyes and keep the heat output and weight/balance to within what you think you could comfortably wear for the length of time required then you could be good to go. I'd still run everything by your school's technicians of course.
> 
> ...




Thanks for the warm welcome. In response to a couple questions/points you made: we never wear plastic over the headlamp so that wouldnt be an issue for the diodes heat dissipation. We have a cap over our hair, then the headlamp over. The headlamp is adjusted prior to scrubbing in. Once we put on our sterile gloves and gown we never touch it afterwards. The light usually stays exactly where it needs to be throughout the procedure. 

Secondly that would definitely be suboptimal if the diode I mentioned gets super hot and/or needs a lot of extra hardware for head dissipation (weighing down my head). My current setup has an associated light box that definitely gets hot, but I figured that with an LED there's a lot more efficiency (more light, less heat). I might just need to buy the diode and experiment with ways to keep it cool. The ideal setup would have a lot of light and minimal weight and heat. 

I agree that the light would need to be 5800K. I think thats what we all currently use, and would probably be annoying if my lamp was a different color. Thanks so much for taking the time for this brainstorming session. Getting in touch with an engineer would be a good idea.


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## nsurgdoc (Jun 27, 2015)

eh4 said:


> "The diode you inquired about is 51mm wide on its bare board and would require a hefty hunk of heatsinking to dissipate the huge amount of heat it produces (literally an 85 watt space heater on your head) - and that heat would then be dissipated right onto your face, whereas the hot bulb in the traditional design is off in its own box leaving only the relatively lightweight lens, fiber optic cable end, and tilt mechanism on your head."
> 
> -Sounds like a job for a heat pipe.



Hmmmm like with a fan diverting the heat? What type of material do you think the ideal pipe would have? Probably not metal- wouldn't want the pipe itself heating. Maybe ceramic? But I wouldnt want it to break easily


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## nsurgdoc (Jun 27, 2015)

TinderBox (UK) said:


> Anything that is going to be used in surgery needs to be able to be sterilized, I dont think you can get an flashlight that you can autoclave or boiled, you could use an liquid sterilizer like Milton tablets/liquid or the equivalent professional version to sterilizer it.
> 
> John.



Ya I'm not going to argue about this. Thank goodness it doesnt need to be sterilized. Once I put it on and adjust it, I scrub in and never touch it after. It never touches the patient or anything sterile. If for some reason it gets knocked out of position, the nurse comes over and helps adjust it for me


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## nsurgdoc (Jun 27, 2015)

SemiMan said:


> Why not just get this one? There is a lot of work that goes into a product beyond just picking an LED. That is the easy part.
> 
> Is that CCT, 6500, typical for surgery now? I would have though something in the 4000-4500 would provide better gamut/rendering of tissue? Task lighting used to be halogen (driven very hard, so 3500+ CCT), so that would imply something in the 4000-4500 for LEDs would be suitable. I have never seen anything that high in a surgical light, generally 3500-5000K but have not looked in about 3-4 years.
> 
> I "whipped" up a headlight for a friend in the medical field about 5-6 years ago for field usage and mixed 3K and 6K for better gamut. It was also much brighter than anything out at the time. It used multiple reflectors with a bit of diffusion. It worked out well.



Ya I cant remember if its 5800 or 6500. I actually think 6500 is correct. Its a super white pure light. But in terms of buying this light, its ~$3500. Would be nice to make one with the new technologies that area available to make it even brighter maybe, and obviously much cheaper. I can see mixing 3K and 6K, which might be better if operating solo, but mooreshire made a good point earlier that if I'm operating with someone else, it'll get annoying if both headlamps have conflicting colors.


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## nsurgdoc (Jun 27, 2015)

recDNA said:


> I'm still amazed neurosurgeons use such bright illumination. I would think the reflection of over 2000 lumens would be blinding. I guess the bright lighting in the theatre helps the eye adjust to such bright lights...and several people wearing such headware all pointed at the same spot. Wow. That's a lot of light. Fascinating.



Ya man brighter is better. ABAT (as bright as possible) haha


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## nsurgdoc (Jun 27, 2015)

SemiMan said:


> High amount of light creates highest pupil dilation resulting in best depth of field and focus.
> 
> High amount of light is also going to help with contrast ratio, signal to noise ratio, as long as you are not saturated, but sunlight is 100K lux, so there is a lot of potential range.



Exactly (except for the pupil dilation part)


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## nsurgdoc (Jun 27, 2015)

Lynx_Arc said:


> To get the kind of efficiency and long running time without burning your skull it may require multiple LEDs as at 2000 lumens output you are driving XM-L LEDs pretty hard efficiency probably is lower than that. Whatever the highest rated output you may want to run the LED at half to 2/3 of that for efficiency sake or end up adding more batteries in the mix. You would also need a pretty good heatsink. My advice is to research 18650 headlamp offerings on the market using XM-L2 and XP-G2 and other latest generation LEDs... perhaps even XPL LEDs as these headlamps have already done most of the homework for you with the exception of an external battery pack. It is possible that there is one on the market capable of such output with an external battery pack if that were so then you could just adapt it for more batteries perhaps by paralleling them in a similar designed pack.



Hey Lynx thanks for another great post. I agree that the better approach might be to use a bunch of LEDs running at lower output to minimize the heat. I was thinking that they are pretty small, maybe 5mm or so, so maybe i can have 4 of them running in parallel. I looked up the LEDs you mentioned and those look great. I even found a flashlight that uses the XM-L LEDs: http://lightjunction.com/nitecore-t...xQT7z9Ogt_IMPQPigRH3EytKuGAbQDLNGEaAj1g8P8HAQ
Something like this might work well for the headlamp with the batteries clipped to my waist. But would the light distribution be less smooth with multiple LEDs? 

The LEDs need to be the right color though, I think anywhere from 5800-6500K would work. I found this old thread that discusses the xm-l2 and xp-g2 and has a picture of what their color looks like: http://www.candlepowerforums.com/vb...s-in-between-Cree-XM-L2-XP-G2-5000K-and-6500K
The picture of nailbender's xp-g2 is definitely the more desirable color. The color needs to be very white, won't work if it's yellow. Reading that thread, if i understand correctly, it can be difficult to order the xm-l2 or xp-g2 diodes with a consistent tint. Maybe I'm understanding incorrectly? But looking at Cree's website it doesn't usually give the kelvin for the xm-l2. But hey thanks so much for your help.


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## nsurgdoc (Jun 27, 2015)

lampeDépêche said:


> I just want to echo Moorehead's comment here:
> 
> "I'm usually all for DIY, but perhaps not when it comes to cranial healthcare."
> 
> ...



Ok I'm gonna take a deep breath here. Making a headlamp that can potentially give me better visibility has an obvious potential to improve patient outcomes in cranial and spinal surgery. And don't come on here telling me to take sterilization more seriously. Tell me why first the headlamp needs to be sterile. Or actually read some basics about the operating room before coming here and making such an ignorant and belligerent comment to someone that spends about 8 hours a day, 4 days per week in the operating room.


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## nsurgdoc (Jun 27, 2015)

broadgage said:


> Anything used in an operating theatre needs to be very clean, but that is not the same as sterile !
> All sorts of sophisticated electronic gear is used in a modern operating theatre and it is maintained to a high degree of cleanness , but not sterilised by boiling or other means.
> 
> A headlight is worn on the surgeons head, which is not sterile and never can be. The surgeons head is of course rendered as clean as possible, and is partly covered by a sterile cap or other covering, but it cant be either completely covered nor be sterile.
> ...



+1. Thanks everyone for your responses.


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## Mr Floppy (Jun 28, 2015)

nsurgdoc said:


> Ok I'm gonna take a deep breath here. Making a headlamp that can potentially give me better visibility has an obvious potential to improve patient outcomes in cranial and spinal surgery.



Which is what the good folk at Welch Allyn do. Not only that, the safety side of things and technical aspects are all professionally manufactured and tested. Down to the material chosen and the custom machining, something that has the highest potential to bring about the best outcome.



> And don't come on here telling me to take sterilization more seriously. Tell me why first the headlamp needs to be sterile. Or actually read some basics about the operating room before coming here and making such an ignorant and belligerent comment to someone that spends about 8 hours a day, 4 days per week in the operating room.



At some point, something is going to get on your equipment. You may not know when or how but there is a procedure that is followed for equipment going in and out of the surgery. It is a regulatory requirement, in this country at least. It varies from department to department and hospital to hospital, but never is the issue of sterilisation not considered. Even if it is not cleaned every time, in the event of something getting on the light or accidental touch there is a protocol to follow. Relying on your insurance if your patient gets a fungal infection is not good enough. 

I will disclose that the only dealings I have with the hospital system is as a computer support / DBA / data entry. Came in with windows 2000, went out with windows xp.


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## SemiMan (Jun 28, 2015)

Surgical headlights are not autoclaved. They must be cleanable with typically 70% alcohol. 

If you want it to be adjustable in use, then it must have a part that is either removable for sterilization and/or a sterile cover can be put over it. I.e. a removable knob or a cover that goes over the knob.

Enova, Surgitel, Integra, etc. ...tons of LED surgical headlights on the market.


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## Lynx_Arc (Jun 28, 2015)

nsurgdoc said:


> Hey Lynx thanks for another great post. I agree that the better approach might be to use a bunch of LEDs running at lower output to minimize the heat. I was thinking that they are pretty small, maybe 5mm or so, so maybe i can have 4 of them running in parallel. I looked up the LEDs you mentioned and those look great. I even found a flashlight that uses the XM-L LEDs: http://lightjunction.com/nitecore-t...xQT7z9Ogt_IMPQPigRH3EytKuGAbQDLNGEaAj1g8P8HAQ
> Something like this might work well for the headlamp with the batteries clipped to my waist. But would the light distribution be less smooth with multiple LEDs?
> 
> The LEDs need to be the right color though, I think anywhere from 5800-6500K would work. I found this old thread that discusses the xm-l2 and xp-g2 and has a picture of what their color looks like: http://www.candlepowerforums.com/vb...s-in-between-Cree-XM-L2-XP-G2-5000K-and-6500K
> The picture of nailbender's xp-g2 is definitely the more desirable color. The color needs to be very white, won't work if it's yellow. Reading that thread, if i understand correctly, it can be difficult to order the xm-l2 or xp-g2 diodes with a consistent tint. Maybe I'm understanding incorrectly? But looking at Cree's website it doesn't usually give the kelvin for the xm-l2. But hey thanks so much for your help.


With the right reflectors or optics you can focus the light to be optimal at a distance range but outside of that range the arrangement of the LEDs comes into play and your light coverage may be more uneven and noticeable. As for the tint and LEDs I would have to differ to others here as I just do not have the expertise in that area I'm mostly talking from reading a lot of information here and some electronics background. I am sure someone can point out a thread or two in the forum that talks extensively about tints and Kelvin I've read into a few but do not have them bookmarked. I'm thinking that you may want to lean into the lower temperature colors like 4500-5500 as I think LED colors in actuality lean towards more bluish and lower temps will have more red and yellow to them which helps things render better. Also CRI can be an issue of which I'm not well versed in.


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## nsurgdoc (Jun 28, 2015)

Mr Floppy said:


> Which is what the good folk at Welch Allyn do. Not only that, the safety side of things and technical aspects are all professionally manufactured and tested. Down to the material chosen and the custom machining, something that has the highest potential to bring about the best outcome.
> 
> 
> 
> ...



We do clean the headlamps with alcohol, but this is obviously much different than sterilizing them. This is a similar procedure as with the loupes we use. Think about if a surgeon wears glasses because he is nearsighted. He uses his own glasses from home. There's no regulatory requirement regarding bringing his glasses in and out of the OR for the purpose of sterility. Surgical infections come from breaks in sterile technique in which something non-sterile comes in contact with something sterile, which then comes in contact with the patient. As another poster alluded to earlier, the surgeons head is not sterile. This includes his facemask, nose, loupes, headlamp, hair, etc. At no point during the surgery can any of these items come in contact with sterile gloves or gown, or with the patient.


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## DrTomPRS (Oct 21, 2015)

Hey, I am a surgical resident as well. I was wondering if any progress has been made regarding this. There appears to be a paucity of headlights available to me as a resident during cases, so having one of my own would be helpful. Plus, I really enjoy the process of making my own device to solve a problem (like everyone else here I'm sure).


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## snowkap (Oct 31, 2015)

check out this site, it 's the headlight we use for dog sledding. The lupine is the brightest and battery pack are quick change, and rechargeable

http://www.coldspotfeeds.com/mushing/headlamps-and-accessories/piko-x-duo-all-smartcore.html


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## Nexquietus (Nov 3, 2015)

nsurgdoc, I'm an OR nurse and we have an Ortho Spine guy that has a cordless LED based head light that is very nice and with it's battery pack lasts all day. I'll try and get you the name and such tomorrow. If nothing else, you can look at the specs and see if it's possible to mimic it.


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## bideshimd (Nov 30, 2015)

Excellent discussion--many thanks to all who have contributed. I am a North American thoracic and cardiovascular surgeon working at a rural mission hospital in Bangladesh for the past 2 decades, and am seeking the same light as nsurgdoc...but on a really tight budget (salary is roughly 5% of my counterparts in USA). I will echo everything that nsurgdoc has stated about sterility (impossible, and also unnecessary) and the extreme benefit of unbelievably bright light when operating with surgical loupe magnification.

Six years ago a generous friend supplied me with an Enova Duo (200,000 lux, 6100K, 2.5" cone @ 14"), and it has been superb. Now I have three junior partners who would all like to have an Enova Duo, or better yet, its replacement the Cyclops XLT-225 (225,000 lux, 6100K, zoomable 2"-5" cone @ 14"). Regrettably the price is about $3500, which is about 50x more than our incomes can afford. So here's what I have discovered after cruising ebay for some possible solutions:
1. zoomable Cree XM-L2 for $13 - remarkably good focus, good color temp, light weight, lasts for 2-3 hours on a charge; nowhere near the 2500lm they state, probably 1/3 to 1/2 as bright as the Enova Duo.
2. 3x Cree XM-L for $17 - good color temp, slightly brighter than the Enova Duo(!), lasts for 1.5-2.0 hrs on a charge, but unfortunately no focus so the cone is about 18" at a 14" working distance, making it unusable. The design has been out for >2 years but is intriguingly similar to the just-released Enova Cyclops XLT-225...albeit without focus.

The million dollar question--what would be the cheapest and most effective way to get the 3x Cree XM-L model to cone down to 2"-5"--either zoomable or fixed at something in the 4-5" range? I visited the local optical shop and tried holding various prescription polycarbonate lenses in front of the light and it had minimal impact.


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