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Percutaneous Muscle Lengthening
including anesthesia, post op needs & limitations.
History:
This procedure started out as a temporary 'make-do' for kids with congenital heart disease further complicated by cerebral palsy (children with heart defects that were in a waiting state for corrective surgery). The energy demands of impaired walking were too much for them, but so too was the anesthesia risk and surgical scope required to fix it (pending definitive cardiac reconstruction).
A specific kind of percutaneous lengthening was devised to minimize trauma, pain and lengthy anesthesia and to allow supine (not the usual prone) positioning. This alteration also reduces, further, the anesthesia complications in this high risk population.
The procedure mimics the mechanics of a "mesh skin graft" (in which a small piece of skin is stretched to cover a large area by way of many tiny holes). A field of parallel cuts is placed on the muscle fascia surface where tendon is originating in the muscle. The skin portal is usually a single almost pin sized entry. This allows muscle-tendon stretch in continuity. It requires nearly no skin incision as the supple skin moves over muscle a good distance. Most pain receptors are in the skin, whereas there are very few in the tendon. This minimizes the pain. The muscle length is judged with as close to awake muscle tone as is possible so as to avoid functional over-lengthening. With experience, it was found that contracture is often and usually confined to very narrow strips of the myofascia - further simplifying the procedure.
Another departure from the more classical procedures is that this procedure is targeted at high velocity muscle components whereas the conventional, by way of sheer bulk result involves the slower muscle components more (more of them, by far). As spastic reactivity is KNOWN - well known - to be velocity related, it makes sense to spare slow components and target high velocity components. The result is a smaller scope of surgery with effects on muscles not operated (as they react globally to the reflexes triggered by the high velocity components).
This 'make - do' procedure turned out to have better functional outcomes than the more conventional methods. It minimized, tremendously, casts and avoids patient down time. We promote immediate resumption of activities (all) including sports. We seldom request additional post op rehab or P.T. (if so, it is usually for some additional issue).
We have learned a few things along the way (nearly 30 years experience and many thousands of cases). Not all muscles that are 'tight' need lengthening. However, some muscles need demolition (better off without) by way of extreme lengthening. The reason is that, sometimes, individual muscles of low bulk but high excursion trigger spasticity of an entire cluster of muscles. This triggering causes far more indirect harm than the muscle has direct contribution. We have learned to identify these cases.
Anesthesia can be local, local plus sedation, or general anesthesia. If we have a very anxious individual, it is kinder to use a brief general anesthesia. If high risk conditions are present then we use sedation plus local anesthesia. If the patient is older and calm (and not needing too many muscles done at once) then just local alone will do. Local anesthetics do have dosage limitations.
If the Achilles - calf muscle complex is lengthened, we use a thin short leg cast (the knee is left free and the toes are also fully exposed and free to move). We do this to prevent the patient's own activities from causing post op over-stretching of the operative site. Also this is the best way to unlearn the pesky off foot postures that tend to become quite habitual and automatic. We discourage cast shoes, as they are not only overly expensive but also wide and awkward. Therefore, a sneaker or sandal is used and full activities allowed and encouraged immediately. Depending on the starting condition, we may use the cast for 4 to 8 weeks (usually 4 for the young patients).
Knees are seldom casted, but cloth (metal stays) night splints are encouraged in many to unlearn the typical fetal sleeping posture of these patients which lends to recurrence. These are generally patients who have had hamstring lengthenings performed.
We have learned that even secondary contractures (joint, ligament etc), respond to stretching once the causal factors are reduced, even in some severe cases. We, therefore, do not try to get a straight knee in one sitting. The lengthenings become permissive of correction rather than directly corrective in these cases.
Some of the more profound contractures require a brace with a hinge that can be step wise adjusted to gradually overcome the long established severe contractures following percutaneous lengthening. This situation is usually the case in the severe elderly long-standing knee contractures that make wheelchair sitting impossible. It is occasionally seen in young but totally untreated spastic cases with knee contractures of long duration.
Blood loss is close to zero. Hospital stay is just for the procedure. In a series of 800 consecutive patients so treated, only three were admitted. All three were admitted for reasons not related to the surgical procedure. Things that may lead to hospitalization (over 25 years of experience) include hemophilia management, platelet administration in patients with advanced liver disease, other types of surgery done at same time, rooming in (twin has bigger op on same day & single parent), known unstable systemic illness and observations requested for medical reasons. Occasionally a child will have marked and sustained nausea after anesthesia and require stay for IV to prevent dehydration. Toe-head blonds and red heads are the ones most likely to have anesthesia related nausea. There is a higher rate of nausea when eye surgery is.
Our current recurrence rate, including all comers, is about 5%. This includes those cases of extreme nature which were planned as staged procedures. A subgroup was followed and reported (see below).
Therapy needs vary with the underlying condition, rather than the surgery, from zero to much.
Cost containment & HMO & prepaid plans: Generally, the reluctance to allow patients to go out of system does not apply here as this technique allows a much less expensive treatment than when kept within the system.
Reasons to do it this way:
1) hospital stay is unusual,
2) seldom a need for additional therapies, and
3) a complication rate approaching zero (see below).
4) The preop customary preparation can be done within the existing plan or referring system, including H&P etc.
5) We have not found a single alternative facility that can do an equivalent treatment for overall less cost. The described treatment and protocols are unique to us.
Timely use of these smaller procedures has vastly reduced the implementation of the much more expensive and physically devastating later interventions so common in the neurologically impaired population. However, it cannot cure all maladies nor replace more conventional treatments in all cases. In some instances, we use these smaller interventions to stage the larger operations at more optimum ages and stages of physical health.
Specifics
Details of surg :
The procedure is done by FEEL through a very tiny puncture site. The part is in motion to gage the tension and range being generated.
Anesthesia :
4 year old without heart or other unstable condition, most humane and best is general anesthesia. Local plus sedation is used by many older patients when there are a small number of planned sites.
Complications :
Anything is possible. So far (last 10 years) there have been no major general complications. It is just a matter of time before there is, however. The biggest worry, numbers wise, is doing too little or too much. We have skewed the technique in favor of the modest side because we can always do more (the complication, then, is merely having not utilized our time well)
Meds, Outcomes & Redo Study : (presented @ Canadian Orthopedic Assn. May 1997 Ontario)
500 consecutive cases, patients under 13y/o excluding those having other kinds of surgery at the same time:
100% follow up
0% infection,
0% vascular or neurologic injury,
0% pain meds after 5 days, 98% pain meds less than 3 days.
In 7 yr. Period:
0% revision,
3% redo for recurrence of contracture of the muscle(s) operated. This 3% is included in:
7% return for muscle surgery at any muscle (including those not operated on - ie: ? missed opportunity ? )
Parent questionnaire : 100% no regrets