Hello everybody,
Just got a reply from Dr Parihar for the questions that have been asked of him. I included the ones that have been posted in the thread as well as a couple of my own.
LL Forum: For cosmetic tibial lengthening it is said that you recommend a maximum 6 cm of distraction. Why is it not recommended to distract beyond this amount and what could the long-term problems be for those who lengthen beyond that? Is this limit the same for cosmetic femur lengthening via external or internal methods?
Dr Parihar: The general experience, and my own experience has been that after 5 cms, people start having trouble with more pain, difficulty to exercise their muscles, and start developing deformities such as equinus (ballerina) and flexion of the knee. Muscles can stretch to a point (like a rubber band), but beyond that point they loose their elasticity (and become like a rope). Initially muscle stretch keeps pace with the increase in length of the bone, beyond 5 cms the muscles are not stretching enough to keep pace with the bone lengthening. They then pull on whatever bone/joint they are attached to and cause deformities which are very difficult to stretch out with physio, and require surgery. One of the earliest patients that I treated (for cosmetic lengthening), was distracting at home, away from Mumbai, under the care of his local orthopaedic surgeon. He had been told very clearly that only 6 cms is appropriate. He was hell bent on 8 cm. He continued lengthening without informing me or the local surgeon (who was supposed to do the followup). He developed severe equinus, which did not resolve despite two years of physio. He finally accepted my advice and agreed for a surgical correction (percutaneous TA release). As a consequence of the equinus, he could not bear weight properly, which in turn created problems in the bone healing. He was fine ultimately, but went thru 2 years of hell, unnecessarily, in my opinion. After that experience, all patients are required to stay in Mumbai for the lengthening period.
In the case of femoral lengthening, a longer lengthening may be possible, because it's surrounded by muscle (unlike the tibia where there are less muscles and more tendons - comparatively speaking). Having said that, external lengthening on the femur tends to cause more problems with muscle scarring and consequent stiffness, compared to the tibia, precisely because the femur is surrounded by muscle. So what one gains in length, one may lose in terms of function. This is the primary reason why most surgeons would not do external femoral lengthening for CLL.
Internal vs External - I have no experience yet with purely internal lengthening, so I cannot say for sure. However, it's a reasonable deduction that internal lengthening in the tibia would not be much different. I would expect that internal lengthening of the tibia would have the same or similar problems beyond 6 cms, which is probably why most internal CLL is done in the femur as it allows for a greater latitude. Being internal, the downside of muscle scarring is avoided.
LL Forum: After lengthening of the tibiae or femurs, how does that affect building muscle strength on the lengthened limb in the long run? Does lengthening cause any degree of permanent weakening of the soft tissues in that area?
Dr Parihar: Within the limits discussed above, I don’t think that there is any permanent problem in the long term. I have not treated any high level athletes, but for people who are only interested in recreational sport, I think they should be able to get back to it in the long run. Problems would be expected if one goes beyond the currently recommended limits - excessive lengthening could cause inflammation in the muscles, which in turn could result in fibrosis, and reduction in function in the long term. One of the issues, is that there is no real data on this. Most CLL patients won’t come back for a detailed functional evaluation 2 years or longer after undergoing surgery. Often, they are reluctant to even acknowledge that they have undergone lengthening, so the problem starts there. If your forum has many members who are more than 2 years out from their CLL, they would be a good place to start asking questions about level of function.
LL Forum: How many nails have you inserted in patients with femur conditions or patients who wish to lengthen femurs for stature increase?
Dr Parihar: I don’t recommend and have done only a single case of LON in the femur for CLL. That was many moons ago, at the beginning of my experience with CLL. I have done it in unilateral cases for smaller lengthening, but even there the numbers are miniscule. Not enough to draw any conclusions.
LL Forum: Are there any differences in how a nail is inserted for a patient with a deformity or leg length discrepancy versus someone who is undergoing a procedure for stature increase?
Dr Parihar: Not really, except that in case of a deformity or LLD, it is sometimes technically more challenging as the bone is bent or narrow vs. someone undergoing a CLL where the bone is usually normal (as noted earlier, not done many nails for CLL in femur). For fractures or deformity correction, we usually use a nail that is well fitting in the medullary canal. In any lengthening, I would ream the medullary cavity to a larger size (about 1.5 or 2 mm more than the diameter of the nail) to prevent any jamming.
LL Forum: The news of Precice being available for internal lengthening in India has generated a lot of interest. In addition to the Precice nail, do you have any plans to add other internal nailing options for stature lengthening at your clinic (such as the Bliskunov, ISKD, Finnish nail being developed, etc.)?
Dr Parihar: With the Precice nail available, I don’t see myself ever using the ISKD or the Bliskunov devices. The Finnish nail - if it comes to India, probably yes, depending on its ability and safety profile. As surgeons we are not necessarily tied in to a particular device. A cheaper device would be good but only when its safety profile and results are equal - i.e. cost is important, but only when safety and efficacy are more or less equal. Anything that is safe for our patients, works reliably, is cost effective, and is technologically advanced, would be put to use (that list seems about right in order of importance).
LL Forum: What are your views on leg lengthening being done over two stages? (i.e. the right leg is lengthened first and then the left leg is lengthened in a separate operation after the first leg has healed.) Some surgeons have advocated this method as being a way to lower the risk of fat embolism with internal methods or LON. Is this practical in your opinion?
Dr Parihar: One side and then the next - if you mean one segment only, then theoretically yes - it would reduce the chances of embolism by half, but practically, it would be difficult for patients to undergo two surgeries. Mainly from the cost point of view. Also, after one side is done, the other side also HAS to be done. With a bilateral, even if the patient decides to stop midway, both sides are equal.
LL Forum: Do you prefer inserting nails into the femurs antegrade or retrograde? Is one more advantageous than the other when considering a cosmetic case?
Dr Parihar: For CLL, antegrade. There is no advantage to doing it retrograde. And retrograde carries the added risk of potential damage to the cartilage of the knee/patella and problems due to that.
LL Forum: In this article by Drs Paley and Herzenberg (
http://www.ncbi.nlm.nih.gov/pubmed/22933497), it said that for internal femoral lengthening "there is a lateral shift of the mechanical axis by approximately 1 mm for every 1 cm of lengthening". Wouldn't this mean that internal femur lengthening has a side effect of causing valgus deformity and potentially osteoarthritis of the knee for putting increased pressure on one side of the knee joint? If so, can the nail be inserted in such a way so as to reduce this lateral shift of the mechanical axis?
Dr Parihar: Lot of potential problems with that article. It's a good hypothesis, but far from being proven yet. There are other articles that have shown the opposite (that there is no real change in the mechanical axis.)
a. They did not correlate the length achieved with the amount of axis deviation. If there is a cause-effect relationship, one should be able to show a positive correlation.
b. One patient actually moved in the opposite direction (medial axis deviation).
c. They state in the article that "
Because of the potential for errors in measurement or radiological magnification, the data were analysed by considering a total shift in mechanical axis deviation of ≤ 2 mm to be inconsequential. With this assumption, further analysis of these 26 limbs showed that 15 limbs had an insignificant total lateral change in mechanical axis deviation of ≤ 2 mm”. i.e. >50% of the limbs did not have a significant change in the mechanical axis.
d. The correct comparison would be the immediate postoperative Axis, and the 6 month postoperative axis - because the surgery itself (osteotomy and insertion of the nail) may change the axis.
