Sunday, March 30, 2014

Bony Outgrowth, osteochondroma

Bone growths in children come in many different forms.  In the upper extremity, there are relatively few growths on the surface of the bones; one of these is the solitary osteochondroma.  The solitary osteochondroma is, as its name implies, a single bony and cartilage growth.  It differs from multiple hereditary exostoses, or osteochondromatosis, which is an inherited condition in which the child has many of these tumors.  Multiple hereditary osteochondromatosis (or multiple hereditary exostoses- MHE) is a topic for a later post (hopefully not too much later).  These are almost always benign growths.

The solitary osteochondroma may appear anywhere but, to focus on the upper extremity, grows from the shoulder blade (scapula), humerus, radius/ ulna, or fingers (phalanges) most commonly.  These osteochondromas typically arise from the growth plate but can also arise from cartilage of the joint.  The osteochondroma is most often painless but may also be painful, especially when pressure is applied to the lump.  There is more likely to be associated pain if it is applying pressure near a nerve or if the bump is particularly close to the skin.  One of the biggest issues is bone deformity related to the growth of the osteochondroma.  This is especially problematic in the forearm (or lower leg) as irregular growth of one bone will affect the growth of the other in the same segment.  The most common situation is when an osteochondroma of the ulna limits the growth of the ulna due to its relationship to the growth plate near the end of the ulna.  If the ulna growth does not keep up with the radius growth, the radius may deform and the radial head will, in certain situations, dislocate at the elbow joint. 

Patients with an isolated osteochondroma present to the orthopaedic surgeon for one of a couple of reasons. First, there may be a painless bump and the patient and family may be curious about it.  If so, it may be observed for growth and possible deformity- xrays are typically taken on an every 6 month or yearly basis depending on the age of the child and the period of growth.  We have to be especially careful to watch for developing deformity during periods of rapid bone growth. 

Second, painful or otherwise worrisome osteochondromas are typically removed but those decisions are to be made after discussion of the pros and cons of such surgeries.  Rarely, a previously painless osteochondroma may become painful; this is a reason to be wary as it could indicate a change in the nature of the benign growth and often warrants an MRI or surgical excision.  

Finally, the bumps may cause the above- mentioned deformity.  The most difficult part of our task is to identify those growths and deformities which are concerning and which may worsen and limit motion or cause increasing functional issues.  If so identified, surgery to excise the osteochondroma and possible cut and realign the bone is considered.

The following images are from an adolescent with a painful (with pressure) and enlarging solitary osteochondroma of the radius.  The size and discomfort led to a decision for surgical removal.  There was no bony deformity aside from the bump.  There were no other osteochondromas and no family history. 

Osteochondroma on ulna.  It is easiest to see on the right picture.

Osteochondroma on the ulna from the side view (lateral).  Not the prominence on the bone.

Osteochondroma at the time of surgery.  This bump was removed.

Charles A. Goldfarb
My Bio at Washington University

Sunday, March 16, 2014

Popular Press on Prosthetics

Prosthetics have been in the press lately.  I have found two issues particularly interesting; one is a note a caution and the other an important step forward.

The first article nicely presents a reality check towards much of the excitement regarding myoelectric prostheses.  While there is good reason to be excited about technology and prosthetics, there are still many challenges to the widespread adoption of myoelectric prosthetics and these devices are not appropriate for all patients.  PBS link

The other issue regarding prosthetics is that, up until now, prosthetics have remain limited by the simple fact that no matter how well they work, the patient cannot use the device to sense their environment. Because the limb cannot feel, the patient must see for use.  There is no sensibility.  That is why, for many kids born with limb deficiencies, prosthetics don't make sense.  Kids born with a limb deficiency learn to function from day of life 1 and many will function better without a prosthetic.  This important ARTICLE in the medical literature summarizes this issue.

A recent study from 2014 from Italy challenges this long held problem.  Raspopovic, et al  wrote about “restoring natural sensory feedback in real- time bidirectional hand prostheses,” in the journal "Science Translational Medicine".

This ARTICLE showed that stimulating the median and ulnar nerve fascicles using electrodes with artificial sensors from prosthesis allows appropriate sensory information to amputee to help control grasp.  That sensory feedback allows the patient to modulate the grasping force of the prosthesis (i.e., how hard to grab) without visual or auditory feedback.  This PIECE  further explains this important step forward.

Wrist Deviation

Radial deficiency and ulnar deficiency are, for most children, easily distinguished.  Radial deficiency, a condition about which I have blogged about on numerous occasions- see here - presents with a problem on the radial (thumb) side of the forearm and hand (mainly the thumb).  The radius bone can be absent or limited and the extensor muscles are affected also.

Ulnar deficiencycheck posts here - can be a bit more challenging as there is more variability in presentation.  In other words, it can be harder to group kids with ulnar deficiency.  The forearm is often affected and the ulna can be absent or deficient.  Sometimes, the radius will be joined, or fused, to the humerus in these kids.  The hand is also more variable as there can be absent fingers on the ulnar side (i.e., ring and small finger) or absent thumb.  

Below is a case which presents like an ulnar deficiency but this child is different than most.  The child is "typical" in the following ways.  First, there is a clear ulnar deviation posture of the wrist.  Second, the thumb is deficient and of limited function as can be seen with ulnar deficiency.  However, neither the forearm nor the thumb are typical for ulnar deficiency.  The forearm has a fusion of the radius and ulna.  The thumb is marked limited, narrow, and of limited function.  Certainly, we do think of other, really rare conditions with forearm synostosis (like Holt- Oram Syndrome or Nievergelt- Pearlman Syndrome)- but this child does exactly fit into any category.

Before presenting the case, I should clarify why it matters- that is, why it matters to make the best diagnosis.  Making the right diagnosis provides a great deal of information to the family about what to expect now and in the future. It lets us know about associated problems or conditions that might not be obvious- these conditions can involve important organ systems like the heart or kidney.  The right diagnosis can let us know about future siblings if the family is considering more kids and also the risks or expectations when the child is considering having his/ her own kids in the future.  Genetic information is becoming more and more available and the cost of obtaining genetic information is decreasing- this will help so much in our understanding of these conditions.  This particular child is also consulting a genetics team for additional thoughts.  For now, I would classify this as an ulnar deficiency but we will continue to work with the genetics team moving forward.

Ulnar deviated wrist.  Note the small thumb which is similar to a finger. The thumb is also not particularly functional and may benefit from intervention in the future.
Another view of ulnar deficiency wrist.

Ulnar deficiency before surgery.  Unusual with radioulnar synostosis.

Ulnar deficiency after surgery.
Ulnar deficiency after surgery.

Ulnar deficiency after surgery.  Pins still in place. 

Sunday, March 9, 2014

Hemangiomas and vascular malformations a brief overview

When we consider congenital abnormalities of the upper extremity, most commonly, we think of extra bones or missing digits.  However, there are many other conditions which fall under this umbrella and, therefore, the care of the congenital hand surgeon.  The OMT classification (Oberg, Manske, Tonkin) has recently replaced the Swanson classification as the official classification scheme for birth anomalies of the upper extremity by the IFSSH.  Section III is for Dysplasias or disordered growth and includes hypertrophy, see previous post on macrodactyly and tumorous conditions.  Vascular conditions including hemangiomas and malformations are thus classified.

Vascular lesions are either tumors or malformations.  Hemangiomas are the most common blood vessel tumor and they are benign (i.e, not bad).  Some consider these lesions a type of birthmark.  Hemangiomas are one of the most common tumors of early life.  These tumors are either visible at birth (congenital) or present in the first weeks or months of life (infantile).  The infantile hemangiomas grow rapidly in the first 6 months to a year of life and then involute slowly (i.e., resolve).  50% have involuted by age 5, 70% by age 7 and most of the rest by age 13.  There can be some hemangiomas that are visible thereafter.   The congenital hemangiomas behave a bit differently as they are fully developed at birth and either disappear in the first year of life or persist.

There are different types of hemangiomas including capillary, the most common in the upper extremity in my experience.  These capillary hemangiomas vary in appearance but one common type is the port- wine stain.  The appearance is affected by the depth of the lesion.  Superficial lesions look red and slightly deeper lesions maybe bluish.  Wikipedia has a good summary.  Here is one capillary hemangioma from Wikipedia.
Capillary hemangioma

Other great pictures are visible online and one good website with nice images is hemangiomaeducation

The bottom line is that most hemangiomas do not require surgical treatment as they resolve with time. However, large hemangiomas can become an appearance and social issue and family- physician discussions may be helpful.

The other type of lesion is the vascular malformations.  These are more common than tumors (approximately 2:1)  They are typically not visible at birth and they grow with the child to become visible or symptomatic later in life.    Malformations occur when the baby is in the womb but, again, continue to grow (often very slowly) after birth and grow in proportion to the growing child.  They can be venous, lymphatic, arteriovenous, capillary, etc.  Venous malformations are most common.

These children may become symptomatic anytime but typically present between ages 2-5.  However, I also see such children for the first time in the teenage years.  Typically, neither the patient nor the family knows when the malformation appeared and it becomes progressively more bothersome as it gets larger.

Here is one example with clinical pictures of a 15 year old male with pain and an enlarging mass in the finger.  It is bluish sometimes and normal colored other times.  It can increase and decrease in size.  This picture is, in my experience, a common situation in that the lesion does not look that "bad."  But, it is growing and can be  painful.  This patient and family requested surgical excision.

Venous malformation, ring finger over middle phalanx.