Principles of Reconstructions of Pediatric Hand

1. Principles of
Reconstruction
Dr. Mohammad Taqi Ehsani
PGY1 of Orthopedics, FMIC

2. Contents:
• Architecture and Hand Physiology
• Nerve Function: Sensibility and Power
• Architecture of the Hand
• Planning Reconstruction
• Evaluation of the Child for Reconstruction

3. Architecture and Hand Physiology
• Successful reconstruction of a child’s hand relies on the well
established principles of hand surgery developed for adults, with
some special considerations for children
• reconstruction is based on understanding the architecture and
physiology of the hand as an organ of motion, strength, and
sensibility
• A short discussion of mechanics and function of this unique element
of the musculoskeletal system is appropriate
• any surgeon’s reconstructive plan must, as much as possible,
restore sensibility, motion, and strength

4. Nerve Function: Sensibility and Power
• The primary consideration in any hand
reconstructive procedure is the ability of the hand
to feel
• Wilder Penfield’s homunculus illustrates the great
importance given to the hand by the sensory
cortex of the brain
• operations designed to improve the appearance of a
crippled upper limb are an important part of
reconstruction, the child’s ability to feel with and
protect the hand is essential for improving hand
use

5. Nerve Function: Sensibility
and Power
• the child’s ability to feel with and protect the hand is the
fundamental reason for failure of long-term use of upper limb
prostheses
• the results of all peripheral nerve reconstructions are considerably
better in children than in adults, due to:
• central reintegration of the defective signal from the periphery
• less to faster or better growth of axons
• the shorten distances of axonal growth needed in a child’s
shorter limb
• the nerve injury must be recognized, repaired, and held in contact
long enough for the child to realize these advantages
• the aftermath of nerve injury is not always more favorable in
children than in adults
• in very young and rapidly growing children, nerve injuries can affect
the length of growing bones, as well as the shape of joints

6. Architecture of the Hand
• Reconstruction of the complex function of the
hand can be facilitated by dividing its mechanics
into two components, a fixed portion
surrounded by a collection of mobile units
• The fixed component is made up of the index
and long finger metacarpals and the distal
row of carpal bones. These six rigid bones
form two arches at right angles to one another

7. Architecture of the Hand
• The transverse arch formed by the distal
carpal row is a semicircular arch.
• The fixed unit of the hand is the foundation
of all hand motion and power for practical
purposes, no movement occurs between
these bony elements
• The stability and alignment of this combined
“foundation” are controlled in space by the
strong flexor and extensor muscles of the
wrist

8. Architecture of the Hand
• The mobile components include three groups
of movable parts
• The first part is the highly mobile thumb ray
radiating off the radial volar side of the fixed unit.
Its complex conical motion and great strength
are the result of a collection of the three joints
empowered by the intrinsic and extrinsic
muscles of the thumb
• The second mobile component consists of the
two minimally mobile ulnar metacarpals,
which in conjunction with the thumb, allow
flattening and cupping of the palm
• The third and highly mobile component is
made up of the 12 bones of the four fingers

9. Architecture of the Hand
• The interaxial lengths of these bones make it possible
for the sensate fingertip to move in a motion
commonly found in nature—the equiangular spiral
• This spiral motion of the fingers accounts for the
adaptability of the hand to objects of any size and is a
consequence of the fact that the distance between the
axes of the joints of the bones of the finger precisely
follows the Fibonacci sequence.
(A) It is the consequence of an arrangement of the distances between the joint axes in a
sequence described by the Italian mathematician Fibonacci: 0, 1, 1, 2, 3, 5, and so
forth
(B) Because the equiangular spiral is a circle with a continuously increasing radius, it
provides an infinite variability in the size (radius) of objects that the digit can surround

11. Planning Reconstruction
• First: address restoration of the fixed unit’s stability in reconstruction of
any complex hand injury or anomaly
• Fusions and osteotomies are used to restore the two arches and their
stability
• Wrist fusion: When adequate power in the wrist motors is absent and
transfers are not available, wrist fusion is required to allow the fingers and
digits to experience the motion provided by the muscles originating above
the wrist
• In general, operations to restore the fixed unit or other elements of the
skeleton require prolonged immobilization.
• As soon as skin coverage is achieved, bone reconstruction takes priority.
• Bone reconstruction must not be combined with operations that require
early movement such as tenolysis, tendon repair, or tendon transfer.

12. Planning Reconstruction
• Reconstruction of the mobile portion of the hand requires
wrist stability, flexible digital joints, gliding tendons, and
the combined power of the extrinsic and intrinsic muscles.
• Without the balanced function of these four components,
the long cantilever of the wrist and multiarticulated finger
falls into the familiar claw deformity
• Although children maintain joint mobility and tendon
gliding better than adults do, the surgeon must be certain
that passive motion of joints has developed before adding
active muscle power.
• If the surgeon cannot move the child’s joints easily with
his or her own hands, it is not possible that the child’s
diminutive muscle that the surgeon transfers to the area
can move them.

13. Planning Reconstruction
• Synergy of wrist and finger motion:
• Active finger extension cannot be restored
without wrist flexion power that is at least equal
to the power of the extrinsic finger extensor
muscles. Conversely, finger flexion requires
active, strong, simultaneous contraction of the
wrist extensor
• The inability of a patient with radial nerve palsy
to make a fist is convincing evidence of this
critical synergism
• When the synergistic wrist motor is not
available, wrist arthrodesis is required.

14. Evaluation of the Child for Reconstruction
• Guidelines from adult surgery are important, but some additional factors
need to be considered before embarking on reconstruction in children.
• Such factors:
• the child’s variable and often limited ability to cooperate in the postoperative period
• the risk associated with anesthesia in early life
• the size of the structures
• absence of critical parts
• the need for growth
• occasionally the reduced life span of some patients with particular congenital
syndromes.
• The goal is to get the best result with the least insult to the limb. This is
important because the healing capacity of the tissues is compromised
by repeated operations.

15. Evaluation of the Child for Reconstruction
• Useful guidelines for decision making in complex reconstruction problems:
1. What is the patient’s problem? This question must be answered after
the diagnosis has been made. Sometimes it can be difficult to get
children or parents to verbalize how their problem really affects their
daily lives. The surgeon must observe and listen carefully to both the
parent and child to discover the child’s exact needs.
2. Goals of treatment, short and long term.
• Treatment of the patient’s short-term goal requires the surgeon to remain focused
on the patient’s problem, as noted previously, and to detect losses that are critical to
the patient’s daily life. Reduced to its basic elements, the hand needs the power of
pinch and grasp with durable, sensate coverage.
• The long-term goal of treatment is to make the patient as independent as possible.

16. Evaluation of the Child for Reconstruction
3. Reasonable methods to achieve these goals. The key here is
reasonableness. Surgeons must carefully consider the probable
responses of the child, the parent, and the tissues of the child’s hand to
the planned operation. In addition, surgeons must realistically evaluate
what they can actually deliver in the operating room and postoperative
period.
4. Reasonable time schedule. Both the surgeon and the family find comfort
when a realistic time schedule is agreed on at the beginning. This
schedule may need revision later, but the child’s exit from the medical
environment should not be delayed more than necessary. Although
follow-up to the treatment is important, the final goal of all surgery is
maximal independent life for the patient. When a treatment plan is open
ended, the child and parent tend to delay taking responsibility for this
ultimate goal.

17. Evaluation of the Child for Reconstruction
5. Outcome evaluation method. All too often, failure to take
preoperative photographs, to measure and record joint angles and
grip strength, and to perform functional tests before treatment
renders an honest, accurate assessment of the result at the end of
treatment impossible. This is as important as establishing the type
of treatment.

18. Thank you
(Reference)