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📚 McCarthy Chapter 45 - Introduction to Facial Clefts

Study Notes (Pages 2437-2441)

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A. INTRODUCTION & OVERVIEW

• Rehabilitation of cleft lip & palate patients involves:
  • Understanding etiopathogenesis/pathomechanics
  • Multidisciplinary diagnosis and treatment team
  • Long-term treatment during growth ("fourth dimension")
  • Technical surgical procedures involving skeletal AND soft tissues
• Key historical reviews: Dorrance (1933), Rogers (1971), Millard (1976)

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B. HISTORY OF FACIAL CLEFTS

The Age of Empiricism

• Cleft lip/palate was considered evidence of an evil spirit in the afflicted child
• Such children were removed from the tribe and left to die

• Victor Veau = "father of modern surgery of cleft lip and palate"
• Converted Langenbeck's bipedicle flaps into single pedicle flaps based on descending palatine vessels
• Pointed out paucity of muscle fibers in the medial aspect of unilateral cleft AND prolabial segment of bilateral cleft lip
• Key teaching:
  • "The median border of the cleft lip is sterile [has no muscle]. The lateral aspect is fertile [has muscle]."
  • "The principal cause of mediocre results in bilateral cleft lip repair is the absence of muscle in the prolabial segment"
  • Surgical directive: "Demand nothing from the inner [sterile] muscles; utilize the outer [lateral] muscles to maximum; sacrifice all mucosa of the inner aspect but preserve carefully all mucosa of the lateral aspect"

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The Scientific Approach

• 19th century - scientific surgical studies blossomed in Western Europe
• Surgery began to be based on precise anatomic studies
• Pancoast (1844): Anatomic observations led him to divide insertion of palatal muscles to prevent straining suture edges (early intravelar veloplasty concept)
• Fergusson (1844-1845): Noted most palatal repairs disrupted; conducted anatomic studies → proposed dividing levator veli palatini, posterior tonsillar pillars, sometimes anterior tonsillar pillars; incisions provided relaxation to prevent lateral pull

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C. VEAU'S EMBRYOLOGICAL CONTRIBUTIONS

• Veau's greatest contribution was in embryology - he became an embryologist after age 60
• Spent many hours studying embryologic specimens
• Challenged the classical "coalescence of facial processes" theory of cleft lip causation
• Supported Fleischmann's hypothesis: Cleft lip is caused by the persistence of the subnarial epithelial membrane (NOT absence of fusion of facial processes)

Embryologic Structures (Critical for Understanding Clefts):

• Formed by the primary palate - a precocious embryonic structure
• Appears at 5mm (2nd week) when mesoderm invades epithelial wall (7mm)
• Definitively constituted when bone begins differentiating into undifferentiated mesenchyme (11mm, 5th week)

• Constituted by the secondary palate - a relatively late embryonic formation
• Definitively constituted when palatine processes achieve fusion (30mm, 12th week)

Key Embryological Concept:

• Malformation in the secondary palate = congenital cleft of palate
• Most often (6 out of 10) - malformation of PRIMARY palate (true cleft lip) is ASSOCIATED with malformation of secondary palate
• These two deformities form a teratologic entity - dissociable because of different embryologic origins but forming a clinical and surgical entity

Fleischmann's Hypothesis:

• Gist: The cleft palate is the arrest of the disappearance of the epithelial membrane which remains intact, not penetrated by adjacent mesoderm
• Veau showed this hypothesis could be applied to all clinical varieties of cleft lip malformation
• Veau studied 140 embryos from 5-25mm in size to arrive at this understanding

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D. MULTIDISCIPLINARY TEAM CONCEPT

• As treatment evolved, ancillary problems emerged:
  • Dentoalveolar arch deformities
  • Nasal abnormalities
  • Maxillary hypoplasia
  • Speech difficulties
• Modern concept: Teams of specialists formed to manage the total problem - too complex for 1-2 disciplines alone
• Especially important for complex craniofacial anomalies (McCarthy, 1976; Munro, 1981)

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E. DENTOALVEOLAR & ORTHODONTIC ISSUES

• Banding and prosthetic stabilization failed to achieve adequate upper-lower dental arch relationship
• McNeil (1954) and Burston (1958) advocated early (first year) orthodontics to establish arch relationships
  • Theory: early alignment aids normal maxillary development
• Problem: Removal of retaining appliance before puberty often caused recurrence of arch deformity → often resulted in Class III malocclusion with significant crossbite after years of treatment

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F. PRIMARY BONE GRAFTING CONTROVERSY

• Initial excitement: surgeons attempted bone grafting at the incisive foramen region to improve palatal closure statistics (Lexer 1908; Drachter 1914)
• Axhausen (1952): adequate bone continuity between premaxilla and lateral bone segments = "final problem in complete clefts"
• Results of primary bone grafting were disappointing:
  • Bone grafts could not "hold apart" arches that tended to collapse
  • Bone graft absorbed under pressure
  • Primary bone grafts did NOT grow as postulated - instead they HINDERED growth
  • Caused significant limitation of maxillary development
  • Dramatic increase in crossbite malocclusion and pseudoprognathism (Kling, 1964)
• Pruzansky (1964): Condemned unscientific use of primary bone grafting
• Current consensus: Most surgeons recommend bone grafting of dentoalveolar clefts at approximately the time of permanent canine eruption (secondary bone grafting) - see Chapter 55

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G. NASAL DEFORMITY CORRECTION

• Periodic advocates of nasal deformity correction at time of primary lip repair
• McComb (1986): Reawakening of interest in primary nasal correction
• Currently there is renewed interest in orthodontic (pin) appliances inserted into infants' mouths to:
  • Recess the protruding premaxilla
  • Expand collapsed maxillary segments

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H. OTHER SIGNIFICANT SCIENTIFIC CONTRIBUTORS (mentioned on page 2441)

• Fára (1968): Anatomy of cleft lip and palate
• Kriens (1969): Research on anatomy of cleft palate and velopharyngeal region
• Lubker (1968): Investigation of physiology of velopharyngeal mechanism
• Warren & Devereux (1966): Work on aerodynamics of velopharyngeal region
• Isshiki, Honjow & Morimoto (1968): Acoustical analysis of speech and velopharyngeal incompetence
• Avery (1962): Embryologic studies
• Stenström & Öberg (1960): Anatomic studies on cleft lip-nose deformity
• Latham (1970): Analysis of the anatomy of the columella
• Johnston: Studies of etiopathogenesis of clefting (see Chapter 48)

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QUICK MEMORY SUMMARY - High-Yield Points

1. First documented cleft lip closure - China ~390 AD
2. Yperman - first FULLY DOCUMENTED description of cleft lip + surgical repair (1295-1351)
3. Paré - "bec-de-lièvre" term + "obturateur" + gold/silver palatal plates (1564-1575)
4. Roux - dramatic voice change after soft palate closure (1819)
5. Langenbeck - subperiosteal dissection → bilateral mucoperiosteal flaps (1859-1861)
6. Veau = father of modern cleft lip & palate surgery; medial border of cleft lip is STERILE (no muscle)
7. Fleischmann's hypothesis = cleft is due to PERSISTENCE of epithelial membrane (NOT failure of coalescence)
8. Primary bone grafting = HARMFUL → hinders maxillary growth; secondary grafting at canine eruption is preferred
9. 6/10 cleft lips are associated with cleft palate
10. Furlow (1986) = double Z-plasty palate closure

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📚 McCARTHY CH. 45 - CLASSIFICATION, EPIDEMIOLOGY & GENETICS

Study Notes with Diagrams Explained

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SECTION 1: CONTEMPORARY THEORIES (p.2441)

Areas of Current Interest:

1. Primary nasal correction at time of lip repair (Blair technique, revived by McComb 1986)
   • Earlier concern: interfered with nasal development
   • Current view: properly executed, restores nasal form WITHOUT harming development
2. Orthodontic appliances in infants - to reposition dentoalveolar segments for better, tension-free lip repair
3. Crossbite & malocclusion after palate repair - combined orthodontic-orthognathic surgical programs

Important Controversy - Anterior Palatal Deformity:

• Walker et al. (1966): Extensive lateral undermining for lip repair has deleterious effects
• Suggested: Lip adhesion first → then definitive closure WITHOUT lateral periosteal undermining → reduces crossbite
• Early complete closure of primary + secondary palates can also cause dental deformities
• Schweckendiek (1962) approach: Close soft palate early → obturate hard palate → repair hard palate later
  • Problem: Cosman & Falk (1980) showed this caused significantly impaired speech

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SECTION 2: CLASSIFICATION

Various classification systems exist; only a few have wide clinical acceptance.

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📊 FIGURE 45-1 EXPLAINED - Formation of the Primary Palate

A → B → C → D → E

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Davis & Ritchie Classification (1922) - Basic Division into 3 Groups

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📊 FIGURE 45-2 EXPLAINED - Veau Classification (1931)

[1]        [2]         [3]          [4]
Soft       Soft+Hard   Complete     Complete
palate     palate      Unilateral   Bilateral
only       to inc.     cleft        cleft
           foramen

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📊 FIGURE 45-3 EXPLAINED - Kernahan & Stark Classification (1958)

• Primary palate = premaxilla + anterior septum + lip (anterior to incisive foramen)
• Secondary palate = hard + soft palate (posterior to incisive foramen)

• Incomplete = cleft of velum only
• Complete = velum + hard palate to incisive foramen
• Submucous cleft = muscle discontinuity; may be hidden unless uvula is cleft - diagnosed by velopharyngeal incompetence + posterior nasal spine notching

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📊 FIGURE 45-4 EXPLAINED - Kernahan's "Striped Y" Classification (1971)

        R          L
    [1]    [4]
    [2]    [5]
       [3][6]
          |
         [7]
         [8]
         [9]

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Harkins et al. Classification (1962) - Detailed Descriptive System

• Unilateral: right, left → Extent: 1/3, 2/3, complete
• Bilateral: right, left
• Median
• Prolabium: small, medium, large
• Congenital scar: right, left, median

• Unilateral/Bilateral → Extent: 1/3, 2/3, complete
• Submucous cleft; absent incisor tooth

• Extent (posteroanterior): 1/3, 2/3, complete
• Width (max in mm)
• Palatal shortness: none, slight, moderate, marked
• Submucous cleft

• Extent (posteroanterior): 1/3, 2/3, complete
• Width (max in mm)
• Vomer attachment: right, left, absent
• Submucous cleft

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Spina's Simplified Classification (1974)

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📊 FIGURE 45-5 EXPLAINED - Tessier Classification (1976)

• Numbers 0-7 = LOWER face (below orbit)
• Numbers 8-14 = UPPER face/cranial extension (above orbit)
• Number 30 = midline mandibular cleft

• e.g., Cleft 3 (lower) + Cleft 11 (upper) = 14
• e.g., Cleft 7 (lower) + Cleft 7 (upper) = 14

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SECTION 3: EPIDEMIOLOGY & GENETICS

Key Distinction - MUST REMEMBER:

CL/P (cleft lip ± palate) and CP (isolated cleft palate) are DIFFERENT ENTITIES with different embryologic, etiologic, and epidemiologic factors

• CL/P → induced by teratogens BEFORE primary palate completely forms
• Clefting of secondary palate (CP) in association with CL/P = likely a secondary tongue-positioning effect (NOT primary defect)

Incidence

• 25% - Cleft lip alone
• 50% - CL/P (combined)
• 25% - Isolated CP

• Left-sided : Right-sided : Bilateral = 6:3:1 (Wilson, 1972)
• Left-sided preponderance is well established
• Cleft palate more often with bilateral (86%) than unilateral (68%) lip clefts

Racial Influences on Incidence

• CL/P: Orientals > Caucasians > Blacks (descending order)
• CP: No racial variation (~0.5 per 1000 births in all races)
• Birth incidence CP: 1/1500-3000 whites; 1/2000-5000 blacks; 1/1600-4200 Asians; 1/1700 Native Americans
• Birth incidence CL/P: 1/775-1000 whites; 1/1370-5000 blacks; 1/470-850 Asians; 1/230-1000 Native Americans

Sex Ratio

• CL/P: Male excess (60-80% in whites)
  • Male preponderance more marked in: severe/complete defects; bilateral > unilateral clefts
• CP (isolated): Female excess
• Clefts extending more anteriorly toward incisive foramen = far more frequent in females

Parental Age

• Risk decreased in younger parents, increased in older parents
• Elevated paternal age (not maternal age) was considered most important factor (Fraser & Calnan, 1961)
• Significant relationship between parental age and isolated CP could NOT be demonstrated in Caucasians

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SECTION 4: GENETIC FACTORS

Important Family History Pattern:

Inheritance Pattern:

• Fogh-Andersen (1942): CL/P inheritance = "variable expressivity"
• Roberts (1964): Multifactorial etiology = multiple genes + environmental factors
• In affected females with CL/P: higher frequency of affected offspring than in affected males

Predicted Recurrence Risk Table (Ross & Johnston, 1972):

• Siblings of unaffected parents: starts at 4.4%
• After 2 affected children born: rises to approximately 9%

Counselling Warning:

Do NOT pool all cleft population data when counselling families (Bixler, 1981)

• An affected parent should NOT be told they carry a flat 5% risk if there are other affected relatives
• In that situation, risk is considerably higher (≥16%)

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SECTION 5: SYNDROMIC CLEFTING

• ~3% of clinic cleft population has identifiable syndromes or pattern of multiple anomalies (Fraser, 1970)
• These do NOT fall into "multifactorial inheritance" category
• Syndromal etiologic factors classified (Pashayan, 1983) into:

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⚡ HIGH-YIELD QUICK SUMMARY TABLE

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