Friday, May 30, 2014

Rare Syndromes: Duane Syndrome with Radial Ray Anomaly

Duane Syndrome is an rare birth anomaly of the eyes in which the patient can't move the eye outward. It has been know to exist for more than 100 years.  But more recently it has been linked to a defect of the SALL4 gene and related to miswiring of the eye muscles or a missing cranial nerve to the eye muscles.

Now, by now, you are wondering why a hand surgeon is writing about a rare eye disorder.  Well, the answer to that reasonable question is that there is super rare link between Duane Syndrome and Radial Ray Disorders (that is radial longitudinal deficiency).  I have previously blogged plenty about radial longitudinal deficiency (link to previous posts) but I found this patient to be very interesting.  His arm has not been treated and, as a teenager, it is rare that we come across such a patient.  He does well functionally but obviously has his limits.  He is limited due to the short forearm on the right, the lack of a good thumb on the right side, and some limited motion and function on the left.  Importantly, the reasonable function on the left makes his overall function ok.  However, we ask whether we can make his function better with therapy or surgery.  While we do not believe straightening the right forearm makes sense, providing a good thumb will help his function.  The pollicization procedure is being planned.

Note short right arm with radial longitudinal deficiency.

Left hand.  There are some forearm anomalies which limit rotation but the hand appears satisfactory.

Severe radial deficiency with a circular ulna- highly uncommon.  There are 4 reasonable fingers and no thumb.

Monday, May 26, 2014

Congenital Radial Head Dislocations: Elbow or forearm problem?

I have previously blogged about congenital radial head dislocation at least several times Previous posts .

However, like most upper extremity anomalies, not all patients with a congenital radial head dislocation present alike.  Consider first that most of these dislocate so that the radial head moves in the posterior and lateral (outside) direction.  A smaller number dislocate in the anterior direction.  And anterior dislocations are most likely to block elbow flexion.  These dislocations may be accompanied but limited forearm rotation (i.e., palm up and palm down) and, less commonly, pain.   But, each child presents differently.

In the recent Oberg Manske Tonkin classification scheme for upper extremity anomalies, congenital radial head dislocation is categorized as a malformation (i.e., problem with limb formation while the baby is in the womb) involving the entire limb but in the radial- ulnar (inside, outside) direction (technically a I.A.2.v).  And while our future understanding of these anomalies will undoubtably grow, I believe this grouping is the right place for this condition.  I believe the following child shows why.

Congenital radial head dislocation with a lack of elbow straightening.

Congenital radial head dislocation with good but not perfect elbow bending.

Congenital radial head dislocation with a very limited ability to supinate (turn palms up).

Congenital radial head dislocation with near perfect pronation (turning palm down).
Congenital radial head dislocation x-rays.  Both the right and left side look the same.  Notice that the radial head is dislocated in the anterior direction.

Congenital radial head dislocation x-ray showing the whole forearm.  This problem is not confined to the elbow but really involves the entire relationship between the radius and the ulna.  The ulna is too long compared to the radius (i.e., at the wrist).

Congenital radial head dislocation is often thought of as an isolated problem to the elbow.  But it is more likely to involve a bigger segment of the limb- the relationship between the radius and the ulna.  This case shows that well and, I believe, a new research project we are working on will confirm that theory.  We have previously looked at a wrist problem Madelungs study a found that a large number of these children actually have a problem in the whole forearm.  Additionally, we have previously shown that surgery at the elbow (i.e., removal of the dislocated radial head) can, in a small % of patients, lead to problems at the wrist.  Which, if you believe that Congenital radial head dislocation involves the whole forearm in some patients, makes complete sense.  Surgery Outcome Results

Charles A. Goldfarb, MD
My Bio at Washington University

Monday, May 19, 2014

Bone/ cartilage tumors/ MHE (multiple hereditary exostoses)

Multiple hereditary exostoses (MHE) is a genetic condition in which a patient has many bone/ cartilage tumors.  It is also know as multiple hereditary osteochondromatosis.  These are "tumors"- unregulated growths- but these are not malignant tumors (since they don't go anywhere- they don't metastasize). This condition differs from a condition I have previously posted: isolated osteochondroma.  The tumor is the same (osteochondroma) but these conditions differ based on how many osteochondromas exist.  In multiple hereditary exostoses, there can be any number of tumors and they can be located just about anywhere in the body: long bones, short bones, scapula, ribs, spinal column, etc.  We most commonly see them involving the radius and ulna in the upper extremity but osteochondromas of the humerus and scapula are also common.

The growths in multiple hereditary exostoses are not present at birth but almost all patients develop them before puberty.  Once skeletal growth is done (mid- teenage years, several years after puberty), new osteochondromas usually do not appear.   There have been two genes associated with multiple hereditary exostoses,  EXT1 and EXT2. Almost all patients develop multiple hereditary exostoses because they inherited it through one of these genes.  The genes are autosomal dominant so there is a 50% chance a child will inherit this disorder if one parent has it.

The exostoses (or osteochondromas) can often be ignored but surgery is considered in a few situations. The first reason to think about surgery is pain.  If painful, most commonly it hurts when the osteochondroma is hit but also if it simply grows large enough to irritate nearby anatomical structures such as nerves.  The second reason to consider surgery is if the growth of the mass is affecting other structures nearby.  Again, this can be nerves or vessels but most commonly it is another bone.  If an osteochondroma grows on the undersurface of the scapula, it can rub against the ribs and be irritating.  Body segments with two bones (radius and ulna in the arm and tibia and fibula in the leg) are at risk for problems with multiple osteochondromatosis as the osteochondroma can affect the growth of one of the bones.  If the radius and ulna (the forearm bones) are not nearly the same length, movement will be affected (rotation of the forearm).  Osteochondromas can slow down the growth of one bone or cause one bone to grow in an angled fashion.  In either case, the balanced forearm can be thrown off kilter and problems can develop.  Classically, the ulna near the wrist may be affected by an osteochondroma, its growth slowed, and the radius continues to grow normally.  Eventually, problems developed due to the mismatched length.

Here is one example.  Both forearms have osteochondromas affecting the distal ulna (near wrist) and the ulna has not grown as it should.  The radius is therefore too long.  On the left side, the radial head has dislocated at the elbow.  On the right side, the radial head is in place but at risk.

Left arm from the back.  Not the prominence of the dislocated radial head.

Right arm from the back.  The radial head is in place.

Both elbows from the back.  The left one is abnormal with a dislocation radial head.

Left forearm.  The radial head is out of position.  See the osteochondroma on the distal ulna.

In this arm, the patient has an osteochondroma on the distal ulna but the radial head at the elbow is still in place.

We treated this patient to attempt to prevent the radial head on the right arm from dislocating.  We sought to do this with an external fixator to lengthen the ulna bone.
External fixator to lengthen ulna to better balance the forearm.  Slow growth of the ulna eventually achieves the appropriate length.
Charles A. Goldfarb, MD
My Bio at Washington University

Wednesday, May 7, 2014

Macrodactyly- Big fingers

Large digits are also called macrodactyly.  This uncommon condition can be quite dramatic in appearance.  I have previously blogged on the topic of macrodactyly- here is the previous Post.  I want to share a few pictures from a single case as a way to demonstrate a typical progression.

This child presented to us a 8 months of age.  He was otherwise healthy and there was no family history of any kind of of bone or joint problem.  The family was obviously concerned.

Macrodactyly on left hand.  Note the very large long finger.
Macrodactyly appearance.  The long finger is obviously too big.  The other digits are not notably different.

Macrodactyly x-ray.

One of the difficulties of this diagnosis is that the decision to the "right" surgery is a hard one.  We can be tempted to debulk or decrease the size of the finger.  The problem with this procedure is that it has to be done over and over again, subjecting the child to many surgeries.  In my opinion (and indeed in the opinion of most of us who see this kind of problem), the best surgery is an amputation of the finger or fingers that are affected.  

Macrodactyly after surgery
Macrodactyly after excision of large digit.
The hand looks much better although there is swelling in the hand.  Motion is very good and the patient is happy and the family is happy.  Over time, the index finger slowly increased in size but not to the degree that the long finger was enlarged.  We did several debulking procedures to help the finger avoid dramatic growth.

Macrodactyly after excision.  This is 7+ years later.  The index finger has slowly grown larger.

The bottom line is the macrodactyly and other overgrowth conditions are challenging for the family and for the treating physician.  There are usually no easy solutions.  We try to minimize the number of interventions while providing the best hand for long term function and appearance.  The good news is that researchers are making progress.  We believe all of these disorders like macrodactyly are related to a signaling mechanism which has malfunctioned.  A cell receptor turns on, growth increases and macrodactyly (or hemihypertrophy, or tumors) result.  Identification of the problem is the first step in fixing it.

Charles A. Goldfarb, MD
My Bio at Washington University



I previously blogged about Robohand 2.0  Previous Robohand Post

The group has now fitted one great patient with an unfortunate injury.  She now has a powered prosthetic and she loves it!  Check out this news story and video.  Fox-2 News Story

Here is another link with more information on the story from Washington University News

Hopefully the group is moving forward with another fitting and additional refinements.  Hats off to Washington University students Henry, Kranti, and Kendall as well as Shriners Hospital therapist Valerie Calhoun!  Collaboration has helped to move medicine forward in so many different ways and this is one small example of how that can work.

The Brain
Another cool story showing how science makes progress.  UK News Story

This one is a little confusing but here is the summary.  A woman was born without a thumb and index finger.  Then she lost her whole hand as a teenager in an accident.  She developed phantom pain which is the phenomenon of pain in a part of a limb that is no longer present (it happens sometimes in amputation patients).  The interesting part is that her phantom pain was for all 5 fingers even though she was only born with 3.  And addition testing showed that her brain perceived that all 5 digits were there. So, despite the fact that she was born with 3 digits, her brain still was mapped for 5.  Very interesting to our understanding of how the brain works.

Charles A. Goldfarb
My Bio at Washington University