Dr Birkholtz, thank you for your providing further advice to the forum, it is invaluable and we all appreciate it. I have been reading some research as of late and am confident certain complementary therapies will be approved for orthopedic use to benefit soft tissue adaptation in the near future or be adopted/recommended in the field. Unfortunately, there appears to be much research on the actual distraction and surgical procedure but very little soft tissue tolerance and adaption, long term consequence, statistics and issues apart from invasive and questionable soft tissue release - do you find this to be true? I have great interest in preventing or managing soft tissue damage as the actual distraction seems 'relatively' straightforward for satisfactory results with a competent surgeon and opinions remain relatively in line with one another, opinions on managing soft tissue vary greatly.
Anyway, I have several questions I wish to ask your opinion on;
A) Rate of Lengthening?I have read some interesting studies on the effects of lengthening rate and the impact on muscular structure and soft tissue damage. As you had said, it would be unwise to extrapolate animal studies to humans but many complications and bad outcomes appear to be at the very least, impacted by excessive lengthening. For some reason, lengthening rate appears to have increased from the recommended 0.5/6mm daily, I have seen examples of up to 2mm daily and I do not believe that soft tissues can adapt to such a rate causing further damage.
Besides the inconvenience and excess time taken, from a purely theoretical point, would the optimal rate of lengthening not be the absolute lowest possible (<0.5mm) split into smaller amounts (5x daily - people have reported less pain with lengthening split - opinion?) throughout the day without risking pre-consolidation and other issues? This of course would be made more difficult with excessive lengthening but with conservative amounts of ~4cm would it not be beneficial? I genuinely believe rate of lengthening plays a massive part to recovery and potential damage. Could it theoretically also be beneficial to split the process into 2 procedures on a single segment with a year recuperation in between for adaptation, for example with the goal of an inch for each process resulting in 2 inches?
What I find very interesting is something that you have mentioned previously, that cell division actually occurs, myogenesis happens to some degree as a reaction to lengthening. As I understand this, this is true adaptation to the new length, at least some of the muscle cells are actually created to compensate for the length of bone rather than stretching - could there be an optimal rate in which myogenesis occurs and damage is prevented? Could this be the key at this moment in time to achieving the best recovery?
We used an experimental rabbit model of leg lengthening to study the morphology and function of muscle after different distraction rates. Lengthening was in twice-daily increments from 0.4 to 4 mm per day. New contractile tissue formed during lengthening, but some damage to the muscle fibres was seen even at rates of less than 1 mm per day; abnormalities increased with larger rates of lengthening. There was proliferation of fibrous tissue between the muscle fibres at distraction rates of over 1 mm per day.
Active muscle function showed adaptation when the rate was 1.0 mm per day or less, but muscle compliance was normal only after rates of 0.4 mm per day. Muscle responded more favourably at rates of distraction slower than those shown to lead to the most prolific bone formation. At present the rate of distraction in clinical practice is determined mainly by factors which enhance osteogenesis. Our study suggeststhat it may be advisable to use a slower rate of elongation in patients with poor muscle compliance associated with the underlying pathology; this will allow better accommodation by the contractile and connective tissues of the muscles.
B) Strong Muscles or Weak Muscles?Most doctors advise that a prospective patient be physically fit (as is advised for all surgeries). Many then seem to concentrate on femur/hamstring/calf hypertrophy and strengthening. Are excessively strong and hypertrophied muscles detrimental to lengthening as stiff muscular structures are or is there no appreciable difference as long as a good level of flexibility is maintained? Would a prospective patient be better spending time on extra flexibility and cardiovascular health in an attempt to minimize hypertrophy? I ask this as I read a PubMed study on the application of Botulinum Toxin A being used during distraction to limit damage to tendons and soft tissues through the weakening of the muscular structures, it seemed to have a notable beneficial effect - what is your opinion on this? This also leads on to...
C) Physical Therapy?It seems to me physical therapy is important for 3 main reasons; 1) To encourage blood flow and healthy bone regrowth 2) To maintain flexibility as supple muscles lengthen much easier than stiff ones minimizing complications such as equinus 3) To prevent major atrophy leading a poor physical condition upon consolidation which will take substantial time and effort to solve but is fully reversible.
This makes me wonder if the excessive physical therapy - hours of hard pedaling on a stationary bike could be detrimental to lengthening and further damage recently stretched tissues prior to an adaptation by exercising them excessively, making the muscles stiff and misplacing the body's much needed reserves for healing and adaptation. It would seem better to attempt to retain some muscular strength and improve blood flow through limited steady, slow pace stationary bike but to focus mostly on flexibility, relaxing the muscles rather than excessive contractions and and use and weight bearing when possible leading.
D) Massage and Timing of Lengthening?Another study I read was on the benefits of massage and hyperbaric oxygen therapy, though I'll not ask about the latter! Carrying on from the previous two questions, what is your opinion on the benefits of massage therapy to aid in ensuring the muscles are supple and reducing stiffness while increasing blood flow during lengthening? I see very little people mention it and I believe it could be highly beneficial. To follow on from this, does the timing of lengthening matter or is it negligible in the grand scheme of the process? - For example, massage and warming up for blood flow and suppleness prior to using the Precice device rather than lengthening a 'cold' and stiff muscle?
E) Soft Tissue Damage - Linear or Exponential?Soft tissue has its elastic limits before plastic deformation and major damage occur. From what you have witnessed, where does this occur? Beyond 10% of initial length or is it once again individual? Is this why the 5cm rule exists as it appears to be the upper limit before major soft tissue damage and complication? Now to the main question, would I be correct in think that damage is not linear and is exponential in nature? For example, lengthening to to the elastic limit is generally safer than lengthening beyond that limit at which damage occurs, that lengthening from 5cm (hypothetically the elastic limit) is less damaging than from 5cm to 6cm and beyond that, the damage compounds which each centimeter lengthened.
F) The True Physical Potential After Lengthening As I understand it, the nature of lengthening and the soft tissue damage is different than most other injuries as they don't change the length of the soft tissue permanently, are there any injuries similar to that of limb lengthening? Many athletes suffer from permanent and debilitating injuries from bad breaks, completely torn cuffs and muscles, snapped tendons that need reattaching etc. many of these injuries can be worked around even if they are never quite as good as before, unfortunately some end sporting careers as they can no longer compete in the top 1 or 2% but by normal standards still remain incredibly fit and athletic, much more than the general population. In your opinion, is there anyway this could be possible with limb lengthening? That through physical therapy and rehabilitation the injury could be almost imperceptible or is the damage to soft tissue just too big of a hit to be able to function to anywhere near the initial level even with perfect conditions and minor lengthening? As much I am an optimist, I fear it may be the latter as I realize that with most injuries, the tissue isn't permanently stretched and in a weakened state, the muscle unable to truly contract to the same degree due to the change of distance between insertion points - almost to the point of your new 'normal' length being similar to standing on your tip toes or beyond prior to lengthening, would this be accurate?
G) The Future With improvements being made in every aspect, from distraction technology such as that of Precise and its upcoming iteration, studies into stem cell therapy and cartilage regrowth to studies into complementary therapies and the usage of things such as botox to prevent the damage initially, do you believe the success and ease of orthopedics and by extension limb lengthening will improve substantially within the next few decades?
H) Ultrasound Bone Healing Do you have experience or an opinion on 'at home' ultrasound devices for consolidation such as the Exogen device?
Author
Topic: Dr Franz Birkholtz (Pretoria, South Africa) (Read 298911 times)