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Author Topic: Surgeon with 1.Navagation System or 2. More Experience?  (Read 2781 times)

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tennis07

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Surgeon with 1.Navagation System or 2. More Experience?
« on: February 16, 2010, 06:53:52 AM »
Hi Everyone!

I have seen several surgeons that do hip resurfacing and have narrowed it down to 2 of them! I like both but am having a hard time deciding on which to go with!

Surgeon A- Uses Navigation system (that assisted in actually developing the software) that guides him with placing the stem so that he can place it exactly where he wants it, and that guides him with placement of acetabular angle within 1 degree give or take of desired angle. But, he has done only 40 Hip Resurfacings. He has had no neck fractures or any issues during or after surgery. (Uses BHR and Cormet)

Surgeon B- Has done over 300 Hip Resurfacings. (Uses BHR, Conserve Plus, Cormet.) (And i see this surgeon tommorow again so I will ask him if he has had any neck fractures or any other complications.)

I feel very comfortable with both! But I am kind of slanting towards Surgeon A due to the fact that he uses the Navigational system which takes the guess work out of placing the stem and the acetabular cup. The only thing is that he's only done 40...but the only reason why the number matters is because of having the practice to properly and accurately place the implant right? If so, shouldn't this not be an issue?

-Jacob
« Last Edit: February 17, 2010, 12:53:44 PM by Pat Walter »

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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #1 on: February 16, 2010, 01:59:39 PM »
Hello Jacob

I only want to give a little extra input about computer navigation systems for resurfacing.  The most expeirnced surgeons just don't use it.  Mr. McMinn and Dr. De Smet are amoung several that have tried it and found the placement of the acetabular cup was not as exacting as when they do it by their own expeirnce.  The navigation system is meant in most cases to be an assist for less expeirnced surgeons to better place the acetabular cups.  The problem with the computer systems is they must be set up properly and remain set.  It is diffiuclt to set them up and if they are not coordinated properly - the surgery results are not as reliable.  I attend the resurfacing courses for surgeons and last Sept. at the 3rd annual hip resurfacing course - there was quite a conversation about computer assisted surgery.  The top surgeons have tried it and do NOT use it.  It will not place components as exact as a surgeon with a lot of expeirnce.

Look at my list and choose a surgeon that has done over 1000 resurfacings.  Only a couple of these surgeons overseas will computer assisted surgery - they rest do not.  http://www.surfacehippy.info/listofdoctors.php

The retention rate of the BHR before the US doctors starting doing resurfacing in 2006 was 99.9%   THose surgeons were not using computer navigation.  Then the US doctors started doing resurfacing and the retention rate dropped to 96%  http://www.surfacehippy.info/bhrhistory.php That meant that the learning curve was steep for the new doctors and one out of four people were having revisions and problems.  So the best way to make sure you do not have post op probems is to choose the really experinced surgeons.

You will also note that the BHR has the best results in the National Registries http://www.surfacehippy.info/nationalregistries.php It is the most used hip resurfacing device world wide and I would study the results before choosing a hip resurfacing device.  Normally the surgeon will choose that for you.  The most expiernced surgeons generally use either the BHR, Wright C+ or Biomet in Dr. Gross's case.  To me that says a lot.  THis is not opinon on my part - but results from the national registries and information provided by the surgeons.  Listen to my current videos that I did in Baltimore - you will learn a lot from some of the best surgeons in the world http://www.surfacehippy.info/shvideos/videosdoctor.php
Normally, the top surgeons attend these courses to learn what is new in hip resurfacing and network with other top surgeons.  They also teach other surgeons.  The doctors that attend the courses take time out of their practices to keep up to date and teach.  That says a lot for these surgeons.  That is the type of surgeon I would want to operate on me.

Good Luck.

Pat
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toby

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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #2 on: February 16, 2010, 07:20:03 PM »
Hi There Jacob,
I'm a proud owner of a Computer Navigated resurface. Please read my recent posts following my op with Prof Cobb on 30 Jan London Uk and who incidentally has performed around 300 now is a talented surgeon without computer assistance but is aiming for 100% every time with every surgeon and has developed the Acrobot planner and surgical navigator.
Jacob, I was in a similar position to you (and have previous postings discussing the issues) but in the end you must follow the research and go with whom you trust and your instincts.
 Note by Patricia Walter - Please note that Pat is not saying the top surgeons are more accurate without computer assistance - the top surgeons themselves shared this information at the 3rd annual hip resurfacing course in Baltimore MD Sept. 2009. This is not Pat's opinon as the poster seems to think. This is the top surgeons including De Smet, McMinn, Gross and others results that they place the components better by experince than by computer assistanceSorry Pat I think you're great but I feel it's too simplistic to say top surgeons are more accurate without etc and don't like using difficult to set up etc  I have concerns about some of these viewpoints. In fact it reminds me a little of the arrogance of those orthpaedic surgeons who tell patients to stick with THR's and avoid the 'newer and less proven Resurfacings'. Note by Patricia Walter - this information is this person's opinon, the most experinced surgeons have excellent records of placing the components properly and do not continue to make mistakes.  This is opnion by this posterEven the most experienced surgeons  have made/continue to make mistakes, with navigated support these could have been avoided particularly re acetabular angle placement which yes less experienced surgeons can get right every time if trained with navigation (if fact Pat, prof Cobb lectured on this and particularly achieving perfect component positioning at the second annual conference in LA when actually even some of the top surgeons were not fully aware of !).
 Please read-The 3 research studies on this site under- 'Medical Studies' all of which conclude- greater accuracy and consisentency with navigated surgery and are consistent with other studies I read a couple of years ago. Jacob From what I've researched some surgeons in the UK who are reasonably experienced 250 plus feel that the Computer assisted/navagational approach(to both plan the surgery and during the operation) combined with their experience will deliver superbly precise component positioning and lead us to a position of even guaranteeing the success of the op and also state a bad day at the office is no longer acceptable. Pat, as I said before, those surgeons who suggest that it takes time to set up the computer system and they don't need it etc are like the rest of us who are resistent to technological change.Note by Patricia Walter - the top hip resurfacing surgeons are certainly not resistent to technological change. They are the ones that have designed the components currently being used in hip resurfacing. They continue to do research and improve hip resurfacing.In fact I can imagine older surgeons finding new technology rather challenging and wanting to keep with what they are comfortable with. I'm a teacher and have fear of new technology.Note by Patricia Walter - this poster does not realize that each of the top hip resurfacing surgons are comfortable with technology - each continues to do research, medical studies, inventing new instrumentation and new surgical techniques. None are too old to learn new techniques or develop new ideas.  Attending the hip resurfacing courses and personally interviewing most of the top surgeons in the world has taught me these are the men at the front of hip resurfacing technology, promoting resurfacing and improving hip resurfacing In addition, I also think that there is a degree of not wanting to use a system not developed by them (a point explained to me by a very eminent ENT professor/surgeon when I went through these points with him during my own research).  I could write more but my new hip is calling me away from the computer for a bit of physical activity.
Love
Toby
Prof C Hippy
« Last Edit: February 17, 2010, 03:59:45 AM by Pat Walter »
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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #3 on: February 16, 2010, 08:24:46 PM »
Hi Toby

I don't want this to become a big number of posts on this subject. I also don't want to scare off perspecitve patients from using the top surgeons that don't use computer placement of devices.  They have excellent records and in their words - don't need the use of the computer assisted placement.  

Please understand - what I say about Dr. De Smet, Mr. McMinn, Dr. Gross and a few others was what THEY SAID about computer navigation.  Not my opinon.  They have all tried it and prefer not to use it.  This was discussed at the last hip resurfacing course in Sept. 2009 in Baltimore. I was at the LA 2nd annual hip resurfacing course and listened to Prof. Cobb's presentation.  I also listed to the presentation this year in Baltimore.  Therefore I was able to not only listen to the live discussion, but also ask surgeons about computer placement. I don't believe they are ignoring the technology or are afraid of it, they have tried it and know it is not as accurate as they can place the components without using it.  That is not ignoring it, that is a choice on their part.

Dr. De Smet has done far in excess of 3000 hip resurfacings and is quite experienced.  One of the top surgeons in the world.

Please don't continue to post that this is simplisitc or any other reasoning on your part.  

THIS IS NOT ABOUT YOUR OPINON OR MY OPINION - THIS IS ABOUT HOW EACH SURGEON CHOOSES TO PERFORM HIS SURGERIES.  The top surgeons like De Smet, McMinn and others have excellent records. You can check the medical studies where McMinn's retention rate was 99.9%   I don't know how you can do any better than that.

You are a teacher - I am a mechanical engineer with a masters degree.  Lets not make this - my doctor is better than yours or I am smarter than you.

Let's leave this topic end here.  Each surgeon will choose the best methods for the best outcomes.  The most expeirnced surgeons in the world are very skilled and have excellent outcomes.  They will change their techniques when they feel there is a need.  Dr. De Smet is always designing new instruments for surgery and I also know Dr. Gross has done the same thing. Dr. Gross is responsible for the cementless Biomet design. He is on the cutting edge and does not want to use computer assisted surgery.  I have talked to him personally along with most of the other top doctors. I listened to other surgeons telling the top medical companies of their ideas at the last hip resurfacing course. These surgeons are not old surgeons who are afraid of new technology.  Dr. Gross is the only surgoen in the US using uncemented technique.  These are the surgeons working with the companies to develop hip resurfacing devices, techniques and instrumentation.  THese are the doctors responsible for the devices used today and are working on the changes of the future. These surgeons are most definitely not the people to point your finger at as those afraid of new technology.  That is your opinon and certainly not true in their cases.  Think about the doctors you are criticizing - the most experienced in the world having done thousands of resurfacings - not just hundreds.

Pat

« Last Edit: February 16, 2010, 09:01:09 PM by Pat Walter »
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obxpelican

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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #4 on: February 16, 2010, 11:08:34 PM »
Sorry Pat I think you're great but I feel it's too simplistic to say top surgeons are more accurate without etc and don't like using difficult to set up etc 

Toby,

It goes without saying the top surgeons in this country have a 1% or less failure rate of cups for instance I do not believe an expensive computer navigated setup is going to help.  Any computer setup must be setup by guess who?   

Sorry, I am not sold on computer navigation systems, when those systems set themselves up without humans (thereby removing human error) you might have something.  Personally I think the systems are nothing but a bunch of hype.


Chuck
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tennis07

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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #5 on: February 17, 2010, 12:22:38 AM »
Hi Everyone!

Thank you for the responses. I have done some research myself and ran across some studies that is kind of pushing me towards the Navigation system.
1:  http://www.ejbjs.org/cgi/content/abstract/90/Supplement_3/65  - Imageless Navigation in Hip Resurfacing: Avoiding Component Malposition During the Surgeon Learning Curve
"Conclusions: Computer-assisted navigation is a dependable and accurate method of positioning hip resurfacing components during arthroplasty, as measured by cup inclination, and a reliable technique for valgus stem placement and avoidance of notching. Furthermore, computer navigation allows for consistency of component alignment independent of procedural experience." "No femoral notching occurred throughout the series. "

2:  http://www.springerlink.com/content/h07n1526525qx0r3/    -Computer-assisted Hip Resurfacing 
"Conclusion
The computer-assisted technique in surface replacement of the hip improves the intra-operative information for the surgeon and enables a precise implantation technique. Possible reasons for complication like femoral notching and varus mal-positioning of the femoral component may be reduced. "

Also, I guessed im lucky in the sense that this surgeon i'm considering actually helped to develop the software system for the navigational system.   

I never thought that at the age of 20 I would have to be deciding things like this! :-)

If anyone else has had Navigation Asissted Hip resurfacing I would love to hear from you!

Thanks,
-Jacob



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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #6 on: February 17, 2010, 12:33:05 AM »
Jacob,

I just did some research on your case (I finally read your early posts) only to find that you have AVN.... dude, skip the fancy computer-assisted surgery and find a surgeon who has a lot of experience with AVN, I would not worry about notching and all the other issues.

If you are not careful you will end up with 2 THRs.

Personally my hats off to you for looking into your surgery as much as you have, I think all patients should be as pro-active as you are being.  I myself when I looked into HRS I did a Winter full of figuring out who to go to for my surgery and I too found out a new type of surgery that does not require the surgeon to use cement on the femoral head side (cups are always cementless).

Since I received my HR I have not looked back.

Sorry that you are so young to be having hip problems so young.



Chuck
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tennis07

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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #7 on: February 17, 2010, 01:32:56 AM »
Jacob,

I just did some research on your case (I finally read your early posts) only to find that you have AVN.... dude, skip the fancy computer-assisted surgery and find a surgeon who has a lot of experience with AVN, I would not worry about notching and all the other issues.


Hi Chuck!

I have seen Dr. Mont and Dr. Brief (who specialized is AVN from HSS), and both agree that Hip Resurfacing is the way to go, especially being so young. Dr. Brief is my main AVN guy and he doesn't do hip resurfacing so he said that I should look for someone down in Dallas (where I live) since my AVN is not super advance(stage 2) so it shouldn't be hard to do, but that if they couldn't do it in DFW then Mont would of course be more than willing to do it. I have traveled to HSS in New York for my Core decompression with Stem Cells and not im gunna lie...flying back sucked!! Horribly!
But, I am definitely sending my Xrays (which i just got them on cd today!)to De Smet, Gross, and Bose and if any of them agree to do it I will definitely be tempted to do it. (Money is another issue since I recieve extremely expensive therapys for my immune deficiency, Autoimmune disease, and Interstitial Lung disease. And since we flew to NY to get the Stem Cells therapy!)
The other reason why I'm looking into the Navigation system is for that reason exactly, I don't want to have 2 hip replacements later on. I want the best placement possible so that it can last as long as possible and [/i] Patricia Walter removed this opinion -  Adds a note - this statement is not based on any medical studies. The top hip resurfacing surgeons that do thousands of hip resurfacings have excellent placement of components. That is why Mr. McMinn had a 99.9% retention rate.  I know perfect placement is key to a long successful HRS which is why I really want to make sure that I'm arming myself with all the knowledge possible so that when I'm considering these surgeon's I can pick correctly.
Right now if it was between......De Smet/Bose/Gross vs Navigation Surgeon..I would definitely go with De Smet/Bose/Gross
But if its ...the local surgeons with 150-300 Resurfacings vs Navigation surgeon I would probably go with Navigation surgeon.

Thanks for the Props Chuck! :-) Its so reassuring to me that I'm making the right decision going with Resurfacing when I hear statments like yours! "Since I received my HR I have not looked back."

Thanks,
Jacob
« Last Edit: February 17, 2010, 02:05:09 AM by Pat Walter »

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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #8 on: February 17, 2010, 01:44:01 AM »
Jacob,

IMHO, you have the best possiblity going to a doctor who is more specialized in AVN, with cup placement you are < 1% the possility of needing a revision, Dr. Gross is < 1% and he does do a bunch of AVN cases and you won't find a better group to work with, the staff and the hospital are fantastic.  I was sold the first time I talked to Lee his assistant.

In a lot of cases even if the cup does not take you can get a re-do so even the < 1 % you sometimes get a re-do.

I would not wait too long on the AVN unless you've been told that it's NOT getting worse.

I do think it's cool that you are looking for the newest and the best but I just do not think the computer assisted surgery is going to change your chances assuming you go with a doctor with lots of experience.


Chuck
Chuck
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Re: Surgeon with 1.Navagation System or 2. More Experience?
« Reply #9 on: February 17, 2010, 01:57:17 AM »
Hi Jacob

I am glad you are consulting with some of the top resurfacing surgeons.

I just have one problem with the statement you are including in your response
even the most experienced surgeons can't guarantee 100% accurate placement since nobodys femoral necks are the same kind of scares me

Where in the world are you quoting that from?  The top surgeons will tell you the number of revisions they have done and why.  They do very, very few.  Mr. McMinn's retention rate was 99.9% and that is posted as a medical study.

Please don't assume doctors can't place their cups and femur component properly.  As I said before - quoting the top surgeons - their placement is MUCH MORE ACCURATE than when placed with a computer.  I am not making that up.  YOu can ask them yourself - which I think you should do. I might even had some of this conversation on my recorder - but would have to get permission to post it.  This was a real discussion last Sept. 09 by the top surgeons including McMinn, De Smet, Gross and a few others.

This argument over computers being better than the top surgeons in the world is not a valid argument.  Look at their revisions rates!  These surgeons have done over 1000 each, some 2000 and others over 3000 each.  

Are you a technically trained person?  If you are you will understand the problems with computers.  Someone has to set the navigation for the computers up - that is based on mapping the patients bone surface.  It is very diffuclt and time consuming to do so and as Dr. Gross mentioned - if it is not done correctly, the components are not placed properly.  Who keeps these computers up and running and calibrated.  If you were in engineering like I was - you would realize how important it is to calibrate all instruments. They are only as accurate as the people or methods used to calibrate.  How many times have you heard about computers having problems!  These computer systems are not different.  There is nothing more unreliable than a computer when there are problems of any kind.  If you worked with computers like many of us do - you would not think they are the answer to the problems of surgery.  They are good when they are working - but never as accurate as the skilled surgeon according to the surgeons.

Please - let's stop telling people that the top surgeons in the world do not place their components correctly and accurately.  These surgeons have great track records and will tell you about them. I will remove any further statements indicating such incorrect information about the top hip resurfacing surgeons in the world.  

Do you realize that at some point in the past the femur cap was positioned to center on the ball of the femur and now is center on the neck of the femur.  There are so many variables that even the best computer programer could not include all the sublties of doing a perfect placement. Do you realize that the surgeon will change the angles just to adapt to the person's body and activities.  A ballet dancer has her placement differently than a soccer player.  All of this is from the doctors experience.  The less experinced surgeons are not able to adjust for all these sublties - they are just trying to get the job done properly.  It is like the top athletes - their experince allows them to do things the less expeirnced athlete does not even think about and they do it without thinking about it.  It all comes from a lot of experience and intuition.  That's how the top surgeons perform.  

Pat
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Dr. Schmalzried Discusses Computer Assisted Navigation for Surgery
« Reply #10 on: February 17, 2010, 04:06:12 PM »
Dear Pat,

There is some data indicating that navigation can improve the accuracy of femoral component placement in hip resurfacing.  The real issue is “compared to what”?  For an inexperienced surgeon, navigation may help him avoid component positioning problems that have been associated with “the learning curve”.  However, for an experienced surgeon, who has an established mechanical alignment system with a high success rate – it is difficult to demonstrate an advantage to him with a navigation system.  Further, the registration process takes a little time – so the cost-to-benefit ratio for the experienced surgeon in a busy O.R. is questionable.  The navigation systems are not hard to learn to use, even for old guys like me!

A bigger challenge is acetabular component positioning.  This is true for total hips, and even more important for resurfacing.  There are 2 parts to the acetabular positioning problem.  The first is identifying the desired position for that patient and the second is putting the cup in that position.  Keeping the pelvis in one position and finding accurate pelvic/acetabular landmarks can be challenging.  The lateral opening angle is the easier part.  Most surgeons today agree that between 40 and 50 degrees is desirable.  Version is more complicated because the desired acetabular version is dependent on femoral version.  Acceptable version is also related to the lateral opening angle and the resultant bearing contact area.  Again, the issue is experience.

If I have any doubt about component positioning, I get an intra-operative x-ray.  Admittedly, there can be some challenges to getting a good intra-operative view.   For what it’s worth, we did an x-ray review of my first 500 resurfacings (minimum 1 year follow-up).  I have never had a femoral neck fracture and all sockets are below 50 degrees lateral opening.

Best wishes.

Thomas P. Schmalzried, M.D.
« Last Edit: February 17, 2010, 04:06:57 PM by Pat Walter »
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Dr. Brooks discusses Computer Assisted Navigation for Hip Resurfacing
« Reply #11 on: February 18, 2010, 11:59:55 PM »
Hi Pat,
 
Computerized navigation has been around for a long time, in total hips, total knees, and now hip resurfacing. A lot of surgeons, including me, have tried it out and not seen an advantage in all but very exceptional cases. Yet other surgeons use it on every case.
 
This is what I think about computerized navigation: It is a tool which can narrow the "bell-curve" of component position, but the curve still has some spread. That helps a surgeon avoid "outliers", or badly misplaced components. Navigation does not make component position the exact same every time, but it helps avoid those outliers. (If it was the exact same every time there would be no bell-curve at all.)
 
So, if a surgeon has no outliers, in other words if he is doing a good job of keeping his personal bell-curve narrow, there is no advantage to using computer navigation. Alternatively, if a surgeon thinks he might accidentally misalign a component so much that it would be considered an outlier, the computer may prevent that.
 
Like any computer, what comes out depends on what went in. Registering the anatomy (which tells the computer where everything is) at the beginning of a computer-navigated operation is not at all an exact science, but depends upon knowledge and experience. It's the same with mechanical alignment jigs. With either method, one should hope that the surgeon is ready to adjust the verdict of the computer or the jig to place the component accurately in the bones which are clearly visible.
 
Are there any downsides to using a computer? Well, there is the extra time involved, which prolongs the surgery (think infections, blood clots). There is extra expense. There is often one more person in the OR, and more traffic in the OR can lead to infection. There is the possibility of surgical complacency if the doctor believes in the infallibility of computers.
 
I have heard this discussed at resurfacing meetings, and people whom I respect more than any others in this field have tried navigation and declared it "useless", and a "waste of time". While unwilling to go quite that far, it does make me think I am fine in continuing with mechanical jigs.
 
Your question about doctors not having 100% "retention" due to component malposition requires a reply. Personally, I have not had any failures in almost 600 resurfacings due to component malposition. I have 1 femoral neck fracture due to leg presses 8 weeks after surgery, and one pelvis fracture resulting from trauma 2 years after resurfacing. That's it. But malposition is an important cause of fracture, wear-related failure, and possibly pseudotumors as well, so should be avoided.
 
Any surgeon "young" enough to learn hip resurfacing is certainly young enough to learn the much easier task of computer navigation, so people who consider someone too "old" to learn navigation are being silly.
 
Similarly, a patient who would choose his surgeon based upon their use of computer navigation is badly misguided. There are many much more important issues to consider.
 
Having said all this, I wouldn't be surprised if at some point in the future surgical navigation becomes more accurate, easier, cheaper, and quicker. Robots will substitute for doctors. Surgeons will look back on the old days and shake their heads in amazement that we used to do all this by hand.
 
Peter Brooks MD, FRCS(C)
Cleveland Clinic


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Dr. Bose Discusses Computer Navigation for Hip Resurfacing
« Reply #12 on: February 22, 2010, 03:03:13 AM »
Hi Pat,
Thanks for the mail.

Using computer navigation in  joint surgery is a double edged weapon. While potentially it can reduce the number of outliers,  it can also cause tremendous deviations and absurd placements which would never be done with conventional jigs. I have seen many examples of this done elsewhere and referred to me for revision surgery.

Generally the input to the computer is made by a technique known as bone morphing where the surgeon uses pointer probes to point out the various bony landmarks to the computer. If the surgeon makes an error in this step then it obviously carries on in all further steps leading to a faulty placement. To argue that it removes human  error is most irrational.

We have the brainlab navigation ( market leader in navigation)  in our unit since 2007 and I did a series of cases at that time ( about 80 cases) . I have to say that the femoral cap placement was inferior to my placement with traditional jigs. However I found it useful when one had distorted anatomy as in previous prox. femoral osteotomy. I still use it for such cases.
 
There are many reasons in my opinion by which the conventional jig is far superior to the navigation in hip resurfacing.
 
1. bone morphing with the pointer probes damages the neck capsule which I protect passionately during hip resurfacing surgery and which I am sure is one of the key elements for my success rate.

2. I  use navigation routinely  during my Total knee replacements as the aim of the TKR surgery is to allign the components to the hip and ankle which are not visible in the surgical wound. In contrast in hip surgery the goal is not to align hip component to the spine , pelvis or knee/ ankle. The aim is to align components to local landmarks in the surgical wound, the location of which is given to the computer by the surgeon.  Then the computer gives back the same information which the surgeon offered in the first place. ( this is unlike the TKR where the computer picks up the hip on merely moving the hip and not morphing). Arguments that the computer increases accuracy in hip surgery is frankly absurd and have to be dismissed as marketing techniques.
 
3. The concept of incorporating the  combined anterversion is now the key in operating on FAI ( Femoro- acetabular impingement) which is the pathology in over 95 % of male patients having primary osteoarthritis. This is a dynamic assessment and can be done only with a jig using a lat cortex pin and cannot be done with navigation.
 
Having said all of the above  one must make a distinction between what Prof. Cobb uses and what others use.

Prof . Cobb is the  only one to my knowledge who uses a CT based navigation. The CT gives information which the surgeon cannot access unlike imageless navigation with all other surgeons which depends on surgeon's input based on bone morphing that  defeats the whole purpose of navigation.

In conclusion I would like to say that imageless navigation has very limited role in hip arthroplasty ( eg previosely operated cases) and is an excellent tool in Knee arthroplasty.
CT based navigation for hips which is still not available commercially ( which prof. Cobb uses) may have a significant role in hip arthroplasty. This has to be balanced with the radiation dose for routine CT to be applied universally( approx 30 -50 conventional x-ray dose )
 
wishing you the very best
 
with best regards
vijay bose
chennai
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Pat Walter

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Dr. Gross Discusses Computer Navigation for Hip Resurfaing
« Reply #13 on: February 23, 2010, 03:27:46 PM »
Dear Pat, 

 Thank you for the work you do, it helps so many. Computer aided navigation is an interesting concept. However, there is no evidence that it leads to better clinical outcomes and fewer failures. On the other hand, there is ample evidence that surgeon experience has a dramatic effect on outcomes and complications. 

 One way to conceptulize this is that the experienced surgeon’s brain is a computer with much more sophisticated "software" than a navigation computer. When a computer is programmed, an algorithm must be created which has certain inherent limitations. Furthermore additional significant sources of errors are introduced by the registration of anatomic points for the navigation computer in surgery.

 My personal opinion is that navigation that is based on a pre-operative CT scan data, which is being pioneered by Justin Cobb, has tremendous promise in the future to improve the results. At this point, we are still in the early development phase. It will probably add several thousand dollars to the cost of each operation. 

 In summary, I believe the right kind of navigation surgery based on accurate 3D CT scans holds tremendous promise for the future. It will still require an extensive amount of preliminary development work before it is ready for routine use. 

 I hope this helps with this very complex issue. 

Best regards,

Thomas P. Gross, M.D.
Webmaster/Owner of Surface Hippy
3/15/06 LBHR De Smet

Pat Walter

  • Patricia Walter
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Dr. De Smet discusses computer assisted surgery for hip resurfacing
« Reply #14 on: February 24, 2010, 07:39:01 PM »
DEAR PAT

WHAT ABOUT NAVIGATION

Today navigation is still a tool that is not easy to use and that needs a certain learning curve as resurfacing itself also has.

So it is not a useful tool today for resurfacing beginners, where it should be! It would be nice if it would be a help at the start of the learning curve.

So can somebody with experience use it or should they use it?

It is like doing a certain approach and having experience with it, so it feels better and confident.

Most of the experienced surgeons do feel they do not need it. MAYBE it could help.

BUT there are some things that have to be cleared out still today:

  • there is no correlation in most of the systems between head and cup.
  • Most of the systems only look to the head, and nobody can tell us today what is now the best place to put the implant
  • It would be the best to use it for the cup because there we have the most failures!
     
 
    
BUT AGAIN the most problems will be with females, that easily have twisted pelvis on the table and smaller sizes, and it is not sure it will have a big influence here.

If it is a system with preop CT of the pelvis to do the acetabulum, the pictures are taken in SUPINE (lying down position!). The patients walk and run on their hips, they do not lie on them, and that can make a complete difference!

So we are not there yet, if something could help me to do better surgery it would be navigation, but as it is today, it is not a 100% proven project. I have today so designed instruments that I call it navigation without navigation; of course in other sites navigation really could help!

I do not know if the 7 malpositioned cups in my series of 3000 would have benefited with navigation, possibly yes, but maybe would have had others where then the placement was worse?

It is the future?, maybe, but not there yet at present for everybody. That is why not everybody is using it, not just because we would be to lazy, to old, to stubborn or whatever.

If it would be used tomorrow in all cases from the start, the worry is also there, that if the navigation fails we do not know anymore what to do. All these facts should not be used for marketing or publicity issues but left to the orthopaedic community to make it better, try it and try to succeed better, what prof.Cobb, myself and all others I think try to do.

KOEN  

koen de smet

hipsurgeon amc gent krijgslaan 181 9000 GENT BELGIUM +3292525903 www.heup.be

anca clinic roma valle giulia ROMA ITALY www.ancaclinic.it
« Last Edit: February 24, 2010, 07:39:54 PM by Pat Walter »
Webmaster/Owner of Surface Hippy
3/15/06 LBHR De Smet

 

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