Sunday, March 31, 2013

Trisomy 8

There are number of different varieties of chromosomal disorders in which there is an extra chromosome, leading to a total of 47 chromosomes instead of the typical 46 (23 pairs).  The most notable trisomy is Downs Syndrome, Trisomy 21.  The more common other trisomies include Trisomy 18 (Edwards syndrome) and Trisomy 13 (Patau syndrome).  Finally, the sex chromosomes can be affected as well- XXX and XXY (Klinefelter syndrome).

Trisomy 8 can be complete (which is usually fatal causing a miscarriage) or can be mosaicism which is less severe and may cause some development delay, decreased IQ, and other physical abnormalities.  This can include short or tall stature, limited facial expressions with wide spaced eyes, a large forehead, and a broad upturned nose.  Another name for Trisomy 8 is Warkany syndrome 2.  It is caused by a random error in the egg or sperm is without a family history.

For the hand surgeon, the most notable musculoskeletal difference is camptodactyly.  This syndromic associated camptodactyly is different than others we have discussed in that it can be more severe and less responsive to stretching.  See previous post:

Nonetheless, the first step in treatment remains stretching and splinting as possible.  If the bent position of the fingers is limiting function and nonoperative intervention is not helping, surgery can be considered.  This child is being treated with therapy alone.  Mom (who was kind enough to allow us to post this picture) is stretching the camptodactyly and there is a forearm based hand splint to extend the fingers at the PIP joints.

Appearance of Trisomy 8, mosaicism. Note his facial characteristics and also the cast on his right foot after clubfoot treatment.
Resting appearance of right hand.  Not index finger camptodactyly especially.

Isolated camptodactyly of index finger.  The finger is in approximately 90 of flexion.

X- ray appearance .  See especially the index and small fingers with camptodactyly.

Friday, March 15, 2013

Great Update

Here is a nice update on our patient- Erickson- born with 3- arms.  Amazing story, more amazing kid.  Also, very interesting blog.

L1 Syndrome and the Thumb

L1 Syndrome is a rare condition that primarily affects the nervous system including the brain but also the nerves to the arms and legs.  The name L1 syndrome comes from the name of the altered L1CAM gene.  Alterations in this gene affect the L1 protein which then affects nervous system development.  L1 Syndrome is passed to children through the X chromosome (X- linked recessive transmission).  Because boys only have 1 X chromosome- if they get this particular X chromosome, they will have L1 Syndrome and so it is more likely in boys.  A girl has 2 X chromosomes and so would need both X chromosomes (one from each parent) to be altered- much less likely.  and .  

Most of the abnormalities of L1 Syndrome are not related to my field of hand and upper extremity surgery.  Each child is unique but there are a series of differences that are commonly seen.  These include hydrocephalus (too much fluid around the brain), mental retardation, delayed speech, and spasticity.  The spastic paraplegia may require a wheelchair but also presents with a shuffling walk.  Like most syndromes, the severity of any one of these problems is different for each child.

The most common hand issue in L1 Syndrome is the adducted thumb- it is the reason for referral to the hand surgeon.  Adduction of the thumb is a position in which the thumb is pulled towards the index (pointer) finger.  The thumb can also be flexed (bent).  This position of the thumb is a problem for 2 reasons.  First, the thumb can be in the way of finger motion (preventing finger flexion). Second, the thumb position simply prevents the thumb from acting like a thumb (i.e., grabbing large objects).   

In the patient below, another issue is the position of the fingers- they are deviated away from the thumb, a so- called wind- swept or wind- blown hand.  This is an uncommon problem also; I most commonly see this in patients with .  This combination of thumb adduction and finger position can also be a type of arthrogryposis (Distal).    

Other conditions can be associated with a flexed/ adducted thumb posture including cerebral palsy (CP) and congenital clasped thumb.  These conditions are each quite different.  CP may respond to splinting and stretching but often surgery to let the thenar (thumb) muscles slide with an EPL tendon reroutement (moving the tendon makes the tendon a abductor of the thumb rather than an adductor) will help.  Congenital clasped thumb (present at birth) may get better with age and splinting but also occasionally requires surgery also.

L1 syndrome patient, left hand.  Note the position of the thumb (somewhat hidden) and fingers around the wheelchair wheel.

The thumb in L1 syndrome. The right hand is more mildly affected here but cannot be straightened or positioned differently.

L1 syndrome.  Left hand x-rays.  The thumb is close to the fingers but the most impressive finding is the position of the fingers.  They are deviated away from the thumb, a "windswept" hand.

Patient with L1 syndrome.  Note his hand position.

In this patient, we will plan to address the thumb with surgery (he has been splinted and in therapy for years).  Hopefully, repositioning the thumb will allow improved overall function.

Tuesday, March 5, 2013

The 5- Finger Hand

The 5- finger hand is a rare anomaly in which there is no thumb, but rather 5 digits in the same plane (i.e., in a row) without a thumb.  That means each digit has three bones (whereas the thumb normally has two bones).  This is important because the normal thumb function is not present because there is no digit where the thumb normally rests.  This means that manipulation of small objects is difficult because the fingers must manipulate the objects, on the side of each digit (scissoring).  Without a thumb the fleshy pulp cannot manipulate the objects.  Also, it is difficult to grasp larger objects because the biggest object is grasped between the fingers (which does have as much space as the thumb/ fingers).  Some children have a "thumb in the plane of the fingers" anomaly which is similar.  However, the difference is that these kids usually have less than 5 digits and have an associated medical problem.  We have shared our experience with this anomaly in the medical literature.

We consider surgical reconstruction of the 5- finger hand to improve function (and also appearance).  The digit on the thumb side of the hand is shortened and rotated to create the function of a thumb.  Sometime an entire bone can be removed or other times the metacarpal bone in the hand is simply shortened.  Here is an example of a 5- finger hand.

5- finger hand

Another view of 5- finger hand prior to reconstruction

Final view of 5- finger hand

There are a few reports of treatment of the 5- finger hand, most recommending pollicization.  and

While the considerations are complex, pollicization is one good option for this anomaly.  Here is our pollicization for this patient.  

Pollicization in 5- finger hand

Another view of pollicization in 5- finger hand.  Note, the new thumb is slightly long (based on discussion with family and possible additional surgery later).

Toe syndactyly, more thoughts

I have previously posted on toe syndactyly with an example of a surgical case.

While this was a fascinating case with a very satisfying outcome, it is unusual.  Most cases of toe syndactyly involve the lesser toes (toes 2-5) and have little functional or appearance issues.  This type of toe syndactyly involving the lesser toes does not affect shoewear, balance, or walking.  Flip- flops can be worn without difficulty.  Many "normal" feet have a partial syndactyly between the second and third toes, an anomaly which is rarely even noticed.  Below is an example of a recent clinic visit for a child sent in with toe syndactyly on both feet.  We elected to watch this and avoid surgery.  Importantly, the hands should be examined also and this child had a partial syndactyly between the long and ring fingers on both sides.

Partial toe syndactyly between the 2nd and 3rd toes

The other foot with toe syndactyly as well.

When we examined the hands, we found bilateral partial cutaneous syndactyly between the ring and long fingers.  We are watching this for now but reconstruction may be helpful in the future.