A New Vocabulary. Secreted Factors. Three Axes of Limb Development 11/9/15. Proteins released from a cell into surrounding area Examples

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1 Congenital Hand Update Terry R. Light, MD Tampa, FL November 7, 2015 Terminology n Difference rather than Deformity n Cleft Hand rather than Lobster Claw Embryonic period - Events Day 26 - arm bud appears Day 33 - hand paddle appears Day 41 - digital rays appear Day 47 - finger separation begins Day 54 - finger separation complete 1

2 A New Vocabulary FGF-8, FGF-4 TGF-Beta Wnt-7a Radical Fringe (r-fng) Sonic hedgehog (Shh) Hoxb-8 Hoxa-11 HoxD Secreted Factors Proteins released from a cell into surrounding area Examples n BMPs - Bone Morphogenic Proteins n Shh - Sonic Hedgehog n FGF - Fibroblast Growth Factors Three Axes of Limb Development Proximal-Distal Anterior-Posterior Dorsal-Ventral 2

3 Longitudinal Axis Upper limb events precede corresponding lower limb events Proximodistal sequence Apical Ectodermal Ridge Proximal Distal Axis 3

4 Proximal Distal Axis Proximal Distal Axis Fibroblast Growth Factor Proteins Necessary & Sufficient for Proximal-Distal Growth n FGF-2 n FGF-4 n FGF-8 Necessary for Prox-Dist Growth (mice) n FGF-10 4

5 Anterior-Posterior Axis Anterior-Posterior Axis Sonic hedgehog (Shh) Expressed by cells making up ZPA Found in inappropriate location (anteriorly) in a strain of polydactylous mice Induces FGF-4 in AER Ties together axes of differentiation 5

6 Dorsal-Ventral Axis Wnt-7 expressed by dorsal ectoderm Absence of Wnt- 7 (mice) associated with palmar duplication Hox genes 38 genes 4 clusters on 4 different chromosomes n HoxA n HoxB n HoxC n HoxD - definition of digital anlagen Programmed Cell Death Inter-digital Web Migration 6

7 GENETICS Muragaki Y, Mundlos S, Upton J, Olsen BR. Altered growth and branching patterns in synpolydactyly caused by mutations in HOXD13. Science. 1996;; 272: Hox genes regulate patterning during limb development. synpolydactyly, an inherited human abnormality of the hands and feet, is caused by expansions of a polyalanine stretch in the amino-terminal region of HOXD13. The homozygous phenotype includes the transformation of metacarpal and metatarsal bones to short carpal- and tarsallike bones. The mutations identify the polyalanine stretch outside of the DNA binding domain of HOXD13 as a region necessary for proper protein function. GENETICS The remarkable correlation between phenotype and expansion size suggests that expansion of the tract leads to a specific gain of function in the mutant HOXD13 protein, and has interesting implications for the role of polyalanine tracts in the control of transcription. CLASSIFICATION Basis n Anatomic n Presumed mechanism Reclassification Schemes n Lumpers n Splitters n Shufflers 7

8 ASSH / IFSSH Classification 1. Failure of formation of parts 2. Failure of differentiation of parts 3. Duplication 4. Overgrowth 5. Undergrowth 6. Congenital constriction bands 7. Generalized skeletal abnormalities OMT Classification Malformations n Failure of Formation entire limb w Radial Dysplasia n Failure of formation hand plate w Symbrachydactyly Deformation n EARS n Trigger Digit Dysplasia n Hypertrophy n Tumorous Conditions Syndromes n Apert Treatment of Congenital Hand Differences Balance n Aesthetic considerations n Functional Considerations Contribute to psychological well being and growth of the child 8

9 Most Common Malformations Syndactyly Polydactyly Radial Deficiency Ulnar 2 bones in L forearm Radius 9

10 hand thumb Radial deviation Anatomy - BONE Classification - based upon degree of osseous radial dysplasia or aplasia Ulnar Length - 50 to 65 % of normal n 18 cm. vs 28 cm. at skeletal maturity Ulnar curvature - postnatal Type III Radial Dysplasia Absent proximal or distal phyis 10

11 Type IV 11

12 Anatomy - NEURAL Combined median and radial nerve n runs along radial aspect of the wrist Anatomy - MUSCULOTENDINOUS Fusion of ECRB / ECRL / BR Tight FCR / PL / FDS / FDP Classification does not grade SOFT TISSUE Treatment Goal Stable wrist Improve alignment of hand and forearm to reverse ulnar prehension pattern Useful arc of wrist motion 12

13 Ideal Single Stage Surgery without excessive soft tissue tension without excessive compression of physis Ideal Single Stage Surgery without excessive soft tissue tension without excessive compression of physis 13

14 Bilateral Centralization & Pollicization K-wires out at 8 weeks Application of Fixator Comprehensively release soft tissues palmarly at time of frame application 14

15 Simple uniplanar frame Fixator Removed Ulnar Incision Excises Pin Sites 3 Months Post Centralization 15

16 RADIAL DEFICIENCY Results of Centralization remain inconsistent and often disappointing n Recurrence is frequent Soft tissue release without osseous repositioning advocated by Ezaki and Oishi Microvascular Toe Transfer advocated by Vilkki INDEX POLLICIZATION A rewarding procedure Technically interesting Indications n Thumb Absence n Thumb Hypoplasia without basilar joint stability Index Pollicization Skin incision Neurovascular dissection Skeletal reorganization Musculotendinous revision 16

17 Skin Incision Expose anatomic structures Create flap to surface first web space Neurovascular Dissection Skeletal Reorganization 17

18 Metacarpal Shortening Musculotendinous Revision 18

19 Shorten Extrinsic Extensors Allow Extrinsic Flexors to shorten over time Transferred digit rests in extension Pre-Operative Prehension Pattern Predicts Post Operative Function Large object grasp improved by pollicization 19

20 Syndactyly Classification Simple / Complex Complete / Incomplete Acrosyndactyly Simple Incomplete Simple Complete Complex Complete Syndactyly - Principle Create a Web Space Floor of true anatomic dimensions with dorsal and/or palmar flap tissue 20

21 Syndactyly Principle Use dorsal and/or palmar flap tissue to create a web space floor of true anatomic dimensions Full thickness skin grafts 21

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23 Syndactyly - Principle Full Thickness Skin Grafts Source = Antecubital Fossa No longer use Groin Crease Are Skin Grafts really needed? 23

24 Poland Association Symbrachydactyly? Part of a teratogenic sequence in which the prototype has short, webbed fingers More severely involved limbs n May lack syndactyly n May lack fingers Differential Diagnosis Early Amniotic Rupture Sequence (Congenital Constriction Bands) 24

25 Differential Diagnosis Early Amniotic Rupture Sequence (Congenital Constriction Bands) Differential Diagnosis Cleft Hand (Typical Cleft Hand) Entire Limb is Affected Humeral Segment 95% of normal Forearm Segment 90% of normal Hand Segment substantially smaller 25

26 SYMBRACHYDACTYLY Syndactyly Release Requires Proximal Stability First Web Space is often narrow 26

27 SYMBRACHYDACTYLY Should nubbins be removed? SYMBRACHYDACTYLY 27

28 Non-vascularized Toe Phalanx Transfer SYMBRACHYDACTYLY Digital Distraction Lengthening 28

29 Consolidation Enhanced 2 digit prehension Microvascular Toe Transfer 29

30 SYMBRACHYDACTYLY Paul Manske Classification of Cleft Hand Based upon First Web Space I: Normal First Web Space IIA: Mildly Narrowed First Web Space IIB: Moderately Narrowed First Web Space III: Syndactylized First Web Space IV: Merged with cleft Functional Abnormalities Thumb Metacarpophalangeal Joint Instability Narrow First Web Space Central Cleft Syndactyly PIP Flexion Contractures ulnar fingers Digital Absence Polydactyly 30

31 Effective Treatment Requirements Release soft tissue between thumb and index Remove bony blocks (transverse bone) Reposition index metacarpal skeleton Surface expanded first web space 31

32 Snow-Littler Skin Flap Miura Incisions 32

33 First Web Space Release Often ignored in enthusiasm to close the cleft Failure to address narrow first web at the time of cleft closure will narrow hand and limit ability to grasp larger objects First Web Space Release Skin Dorsal Fascia over 1st Dorsal Interosseous Thumb MC origin of 1st DI Fascia over Adductor Pollicis Abnormal Adductor Pollicis origin on Index Abnormal Intrinsic Muscles Sheet-like merged thumb-index extensor Middle-ization 33

34 Resect Portion of Transverse Phalanx Splaying Metacarpals Apart 34

35 Cross Bone Transverse Phalanx Goal = Expand T-I Distance 35

36 Reality = Unchanged T-I Distance Reality = Unchanged T-I Distance Insert K-wire in Index Metacarpal Helpful in controlling rotation 36

37 Opening wedge osteotomy of index metacarpal brings metacarpal parallel to ring metacarpal K-wire advanced into ring metacarpal secures rotation A-1 Pulley Reconstruction of Transverse Inter-metacarpal Ligament MULTIPLE HEREDITARY EXOSTOSES 37

38 MACRODACTYLY Timing of Surgery Not critical but ideally as soon as the operation may be safely and correctly planned and carried out Typically age 1 Perhaps age 3 38

39 Which Ray to Delete? 39

40 Acceptance enhanced by role models DEPARTMENT OF ORTHOPAEDIC SURGERY AND REHABILITATION Loyola University Chicago Stritch School of Medicine 40

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