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Operationsmetoder/
Surgery methodes
at Texas Childrens Hospital
Primary Surgery in Children with Brachial Plexus Injury.
The protocols at Texas Children's Hospital are based on our population of over 1300 children with obstetrical brachial plexus injuries seen in the last 12 years. Our total experience with primary surgery (surgery of the injured nerves) is over 530 patients. Generally, if there is continued significant shoulder and/ or elbow weakness by the age of 4 to 6 months of age, and certainly if there is significant weakness in the biceps muscle by 6 months of age, we believe that surgical exploration is indicated. The intraoperative nerve testing then defines the specific procedure used to improve arm function. It is very important to note that in 12 to 18 months following injury, denervated muscles will not accept a new nerve supply, and remain paralyzed or weak permanently. Because nerves only grow back at one inch per month, time is of the essence in managing these and any other nerve injuries. Bone deformity can accompany longstanding paralysis of any limb in growing children.
Specific nerve surgeries that we use are: nerve scar excision (neurolysis), nerve grafting, nerve transfer and neurotization. It is sometimes necessary to perform tendon lengthening procedures in infancy in conjunction with the nerve procedures. These procedures are complex and must be used judiciously in order not to burn bridges for future reconstructive options.
If your child has weakness of shoulder, elbow, and/ or hand by the age of 3 to 4 months, we strongly recommend consultation with a surgical specialist with extensive experience in obstetric brachial plexus injury.
We have found this series of steps to offer optimal results. The specifics of application to each child is highly individual, however, and of course other centers may have different management protocols.
EMG's are ideally done at 4 to 6 weeks of age to set a baseline for further evaluation in the future. Similarly, an MRI around that time can be done to determine whether root avulsion (tearing of the roots from the spinal cord) is present, although this test overall is less important than a good EMG examination. The EMG should then be repeated around 3 to 4 months of age to see if improvement has occurred electrically, and to correlate with the physical examination. Generally speaking, if there is not full movement of all elements of the arm (shoulder, elbow, hand) by 3 to 4 months, serious consideration for operative exploration should be initiated. If there is no elbow flexion by 6 months of age, surgery is definitely recommended.
Some modifications to these general rules are: [1] complete injury to all roots with no movement in any part of the arm by 3 months will indicate surgery at or before 3 months; [2] continuing improvement in arm function by 4 to 6 months will delay or contraindicate surgery at that time, but if improvement stops later, surgery might be indicated, as in part [3]; [3] patients who arrive at our clinic well after 9 to 12 months of age with continuing elbow weakness and other deficits will require 2-level reconstruction, at the level of the nerve roots and in the axilla with appropriate nerve transfers and releases;[4] patients who are seen after 2 years of age for the first time are best managed with nerve releases and muscle/ tendon transfers.
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Secondary Surgery in Children with Brachial Plexus Injury (Mod Quad Operation): This does not mean that the primary surgery did not work. It describes another type of surgery later in time used to correct muscle imbalances.
The situation of muscle imbalance is very common among patients with Erb's palsy and with other brachial plexus injuries. In our experience the majority of children whose injury does not resolve completely by 3 to 4 months of age will end up with a specific series of arm restrictions caused by a muscle imbalance between injured and uninjured muscles. Among the muscles injured in Erb's are the abductors of the shoulder (that lift the arm over the head), as well as the external rotators (that help to turn the upper arm outward and to open the palm of the hand).
At the same time, the internal rotators (muscles that turn the arm and palm inward) and adductors (muscles that pull the arm to the side) of the arm are not involved in the injury because they are supplied by the lower roots of the plexus. Therefore, these strong muscles overpower the weak muscles and over time the child cannot lift the arm over the head or turn the palm out, because of the muscle imbalance.
In order to use the hand effectively, the elbow becomes bent, and this eventually becomes fixed because of weakness of the triceps (the elbow straightening muscle). The elbow-bent posture contributes to the appearance of the arm being shorter, although it probably is in reality not much shorter when measured.
For this muscle imbalance, there is a very effective group of muscle releases and transfers which can put the arm in a more natural position and help to lift the arm over the head. We refer to this operation as the "quad" procedure because it has four components ([1] latissimus dorsi muscle transfer for external rotation and abduction [2] teres major muscle transfer for scapular stabilization [3] subscapularis muscle release [4] axillary nerve decompression and
neurolysis). Depending on the individual child, other nerve decompressions or muscle/ tendon transfers (such as pectoralis muscle releases) might be performed at the same time (the modified quad or "Mod Quad" procedure).
We have performed the quad procedure on over 350 children with Erb's palsy and have been very excited about the degree of movement that is gained. On average, we find a 70 degree improvement in abduction and 60 degree improvement in external rotation at 6 months after surgery; these results should improve with time. We find that the best time to do this procedure is 2 to 4 years of age, but we have been very successful with older children and adults as well.
Additionally, wrist, finger and thumb movements are often affected, leading to problems with hand grasp and finger pinch. A series of tendon/ muscle transfers can help to achieve excellent function with these injuries as well. The basic principle is that some strong muscles and tendons can be re-routed to strengthen weaker functions by sewing the transfetendons into the paralyzed ones.
Each child of course is very different in terms of type of injury, level of function, age at presentation, and many other elements which are addressed individually; it is often possible that patients require a combination of protocols for optimal recovery, in our experience.
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The Future of Brachial Plexus Surgery
This is an exciting time to be involved in the field of brachial plexus injury and rehabilitation. The last few years have brought many new advances in management as well as the promise of future breakthroughs. It is our belief that practitioners in the field of brachial plexus injury have a responsibility not only to provide the best and most advanced care to their patients but also to undertake research into clinical and basic science aspects of this complex field.
Brachial plexus injuries are probably the most difficult management problems faced by neurologists, rehabilitation specialists and reconstructive surgeons. The anatomy of the brachial plexus is extremely complicated and most injuries affect the entire plexus to some degree. Current management is primarily based on the fact that muscle which loses its nerve supply (as in brachial plexus injury) will become completely wasted after about 15 to 18 months in children and cannot be recovered after that time. Repaired nerves grow slowly, about one inch per month, so that time is of the essence in performing surgery. Therefore, it is often necessary to operate on children at the age of 4 to 6 months, simply to allow sufficient time for the repaired nerves to grow down the length of the arm to the weakened muscles. Of course, recovery of sensation is also important, but there does not appear to be any time constraint on the recovery of feeling as there is with muscle.
Excellent recovery of arm and hand function is possible if surgery is done at the appropriate time, but in many cases this is not feasible because of various circumstances. In the past, these cases would have an uncertain outcome, but with new technology currently available and on the horizon at Texas Children's Hospital, the outlook is much brighter.
Several cutting edge clinical and research programs dedicated to improving the outcome of children with obstetric brachial plexus injuries are currently in place at Texas Children's Hospital:
A. Surgical Techniques
[1] Nerve Transfers:
At Texas Children's Hospital, we have been using the technique of "nerve transfer" in children who are older or who have had exceptionally severe injuries resulting in avulsion of the nerves from the spinal cord. Nerve transfer basically involves the use of an uninjured donor nerve that is relatively unimportant to supply function to a nerve that is injured but important. For example, in the case of some shoulder muscles, part of the nerve for shrugging the shoulder or one of the arm nerves can be used as a donor. Similarly, part of one hand nerve can be used to give strength to the biceps muscle for elbow movement. Many other donors are used. Texas Children's Hospital has been a world pioneer in the use of nerve transfers in obstetric brachial plexus injuries, and has the largest number of patients who have been benefited by the technique. Because the donor nerves are very close to the recipient muscles, the time and distance of nerve growth necessary for function is much less than if repair is performed in the neck.
[2] Muscle Stimulation:
Our Brachial Plexus Clinic is one of only a few centers in the world approved by the FDA to do human research on implantable muscle stimulators, which have been shown to preserve muscle strength when its nerves have been injured. This allows a longer time before the muscle becomes atrophic and has been shown to enhance final strength after nerve repair. We currently are preparing a proposal to be sent to the FDA to approve these devices for use in children with brachial plexus injuries. We have used one such device in a child with excellent early results.
[3]Nerve Transplants:
One of the major problems in repairing brachial plexus and other nerve injuries in children is the relatively small amount of donor nerves for grafts available in children, due to
their small size. The Brachial Plexus Clinic at Texas Children's Hospital has team members with training and experience in using nerve transplants in children with severe nerve injuries. We recently have performed the world's first brachial plexus nerve transplant from a father to his child. The child will need anti-rejection medication for up to 12 months following surgery but this is discontinued after that time so that lifelong therapy is not necessary and complications of the medication are minimized.
B. Clinical Research
[1] Magnetic Resonance Spectroscopy
The technique of nerve transfer has salvaged function in otherwise hopeless brachial plexus injuries. Success of the surgery depends upon the brain reorganizing to allow nerves to perform functions they were not originally intended to do; for example, using part of a nerve to the hand for biceps movement. Or, using intercostal (rib) nerves to give biceps function. The technique of magnetic resonance spectroscopy
(MRS) will allow us to see which parts of the brain reorganize to give function to paralyzed muscles after nerve transfer.
Another area of interest for us is to carefully examine the spinal cord in the area of the brachial plexus to look for signs of injury. It is not unusual for children with brachial plexus injuries to show signs of foot and leg weakness on the same side when they grow up. This is possibly due to a traction injury of the spinal cord itself, and can be evaluated with MRS as well as routine magnetic resonance imaging
(MRI). Steroids are known to reduce the overall effects of spinal cord injury and it may be that they would be useful at the time of obstetric brachial plexus injury as well.
[2] Outcome Studies
Every child seen in the Texas Children's Hospital Brachial Plexus Clinic is entered into a comprehensive database that allows us to track outcomes of management. Educated management changes can then be instituted based on long-term follow-up of patients as they grow up. The key concept here is "long-term", as changes made without careful analysis can lead to faulty decision-making.
As an example, our clinic has been performing more muscle transfer and nerve decompression surgery in the past 3 years as a response to our analysis of the preceding several years of experience with primary surgical outcomes. After carefully analyzing our results in about 250 children followed for 5 years after primary surgery, it was obvious that shoulder function was not returning as reliably as biceps function. The success of our shoulder muscle transfers (the "Mod Quad" procedure) in increasing shoulder and arm function is an excellent example of outcome studies leading to improved functional status.
We currently are tracking outcomes of specialized procedures in tendon transfers, nerve transfers in the neck and arm, as well as a multitude of other procedures including splinting for muscle contractures and the effectiveness of external muscle stimulation
(e-stim).
[3] Physical Medicine and Rehabilitation
Innovative splinting and dynamic bracing protocols are currently being used in our Physical Therapy and Occupational Therapy Departments. These techniques assist in maintaining neutral postures and in helping active motion in recovering muscles following nerve injury and nerve surgery. We believe strongly that excessive casting and immobilization is unnecessary and detrimental to the well-being of the child. Our experience with over 1300 children and 12 years of management of these injuries has shown that carefully constructed and customized splints lead to the best outcome with the least discomfort.
The increasing use of electrical muscle stimulation is being actively investigated in our clinic in hopes of defining the optimal clinical settings for the effective use of
e-stim.
Basic Science Research
All members of the Brachial Plexus Clinic team are full-time faculty members of the Baylor College of Medicine. As such, team members are actively involved in laboratory and clinical research projects which will improve the outcomes of brachial plexus injury.[1] Nerve Regeneration
One of the most actively pursued areas of research is nerve regeneration. We currently have a full-time PhD. In the laboratory who is actively engaged in Gene Therapy studies for nerve regeneration funded by the National Institutes of Health. The hope is that regenerating nerves following brachial plexus injury can be made to grow faster and more efficiently through the use of gene therapy.
[2] Nerve Scarring
Following injury to nerves, a neuroma often forms. A neuroma is a mixture of regenerating nerves and scar tissue formed from the connective tissue forming the outside of the nerve. This scar is often dense and thick enough to prevent nerves from re-growing effectively. An active area of research in our clinic is the blocking of this scar through the use of specific DNA molecules that prevent its formation. This is another example of gene therapy which will someday improve the outcome of brachial plexus injuries.
[3] Laser Repair of Nerve Injury
The use of lasers for medical and surgical therapy is growing rapidly. We are currently evaluating several types of laser in the laboratory for use in repairing injured brachial plexus nerves in children and adults. It may be that the laser will provide a better and more accurate surgical repair than the use of microsutures.
[4] Artificial NervesWe are attempting to grow artificial nerves in the laboratory so that nerve grafting will not have to rely on harvesting of donor nerves. One way to do this is to use amniotic cord tissue with Schwann cell cultures embedded within the cord, thereby creating an artificial nerve. Laboratory studies are currently proceeding with exciting early results.
The future of brachial plexus injury management appears very hopeful. Our focus at Texas Children's Hospital Brachial Plexus Clinic is in continuing to provide state of the art management with an eye to future improvements based on innovative clinical and basic science research.
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Dr. Rita Lee, Dr. John Laurent, Dr. Saleh Shenaq, Dr. Rahul Nath and Dr. Maureen Nelson, Texas Children's Hospital Brachial Plexus Program, Houston, Texas.
For more information, contact Lisa Davis, RN, at either 1-800-364-5437 or 832-824-3290; or, send an e-mail to Dr. Rahul Nath at
rnath@bcm.tmc.edu
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