🧠 Cleft Lip & Palate — Embryology + Functional Anatomy

Cummings Otolaryngology, Chapter 18 (pp. 187–189)

PART 1: EMBRYOLOGY

The 5 Facial Prominences — The Foundation

Memory hook — "FNP Makes Me Laugh" = Frontonasal, Maxillary, Mandibular, Lateral nasal, medial Nasal → the 5 facial prominences.

The Lip Forms: Weeks 4–6

Bilateral maxillary prominences (MAX) fuse with the medial nasal prominence (MNP) → forms the lip and alveolus

• This occurs between weeks 4 and 6 of gestation
• The frontonasal prominence splits into MNP + LNP via a nasal pit on the ventrolateral aspect
• Failure or aberrant timing of this fusion = cleft lip

The Palate Forms in Two Phases

1. Palatine shelves grow as outgrowths from the maxillary prominences
2. They initially grow obliquely downward (tongue is in the way)
3. They then rotate to lie horizontally over the tongue
4. Fuse with the primary palate, then anterior → posterior
5. By week 12 — palate is complete

Memory hook: "Shelves go DOWN then ACROSS" — palatine shelves descend then rotate horizontal to fuse.

• PP = Primary palate (anterior, from MNP)
• LPS = Lateral palatal shelf (from maxillary process)
• S = Nasal septum (divides the two shelves from above)

Risk Factors for CL/P (Box 18.2)

• Age
• Smoking (↑ risk by up to 20%)
• Obesity (BMI >30)
• Pre-pregnancy diabetes
• First-trimester heavy alcohol use

• Anticonvulsants
• Folate antagonists
• Retinoic acid

• IRF6 gene variants → Van der Woude syndrome (Mendelian)
• TGF-b3, NAT1TBX22, MSX1, FGFR — non-syndromic associations
• 22q11 deletion → cardiac malformation + cleft palate (up to 40% prevalence)

• 1° relative with cleft → 3.5% risk for child
• Parents with one affected child → 2–5% risk for next child

PART 2: FUNCTIONAL ANATOMY

The Lip — 3 Zones + 1 Key Muscle

• Normally forms a complete sling under the mucosal covering
• In cleft lip: the muscle inserts aberrantly into:
  • Dermis and nasal ala on the cleft side
  • Columella on the non-cleft side
• This breaks the continuous sling → loss of normal lip sphincter function

• M = Myrtiform head of nasalis muscle
• O = Oblique head of orbicularis oris
• T = Transverse head of nasalis muscle
• The muscle fibers run aberrantly toward the nasal ala instead of crossing the midline

Memory hook: "MOT-or of the lip" — M, O, T are the three muscle heads shown disrupted in cleft lip.

The Nose — Secondary Deformity from Muscle Aberrancy

1. Orbicularis oris inserts into nasal alar base → outward splaying of lower lateral cartilage
2. Alar base sits more lateral and inferior than normal
3. Lower lateral cartilage shape changes:
   • Shorter medial crus
   • Longer lateral crus
   • Flattened, wider dome
4. Columella is shortened
5. Anterior cartilaginous septum deviates to non-cleft side (unopposed pull)
6. Septum bows onto cleft side posteriorly

Memory hook: "SALFD" — Splaying, Alar base descent, Lateral crus longer, Flattened dome, Deviated septum.

The Palate — Velar Muscles (Figure 18.7)

• Originates from medial Eustachian tube + petrous temporal bone
• Runs anteriorly → enters middle third of velum transversely
• Meets its partner from the opposite side → forms the levator sling

• Loses transverse orientation
• Instead runs longitudinally → inserts into bony cleft margin + posterior palatine bones
• Cannot form a levator sling → velopharyngeal port stays open → nasal escape during speech

• Thin sheet → forms anterior tonsillar pillar
• Origin: back of palatal aponeurosis + maxillary tuberosity

• Substantial muscle split into 2 heads by levator insertion
• Runs down → posterior tonsillar pillar → thyroid cartilage + pharyngeal aponeurosis
• Acts as depressor of velum

• Originates: sphenoid spine + scaphoid fossa + lateral lamina of Eustachian tube cartilage
• Forms a tendon winding round the pterygoid hamulus → spreads as fibrous aponeurosis in anterior ⅓ of soft palate
• Function: opens Eustachian tube (hence high rate of middle ear disease in cleft palate)

ENT Issues in Cleft — Key Points (Page 3)

• Micrognathia + glossoptosis → tongue falls back and blocks airway (Figure 18.8b)
• Neonates are obligate nasal breathers (infantile larynx sits high, epiglottis visible behind soft palate)
• PRS monitoring: overnight oximetry + CO₂ measurement within first 4 weeks of life
• Worsening obstruction between 4–8 weeks
• Airway options:

MEMORIZATION FRAMEWORK — Rapid Review

THE "5-FUSION-FAIL" RULE OF CLEFT LIP EMBRYOLOGY

5 prominences → 2 fusions needed → 1 window (wks 4–6) → 
Failure = cleft lip (MAX + MNP) or cleft palate (shelves, wk 6–12)

THE "MOT-OR-NOSE-PALATE" CHAIN OF FUNCTIONAL ANATOMY

Orbicularis oris fails to form sling
  ↓
LIP: No vermilion continuity, no oral sphincter
  ↓
NOSE: Alar base splays → lower lateral cartilage distorted → septum deviates
  ↓
PALATE: Levator runs longitudinally → no sling → no VP closure → nasal speech
  ↓
EAR: Tensor veli palatini dysfunction → Eustachian tube won't open → OME

SELF-QUIZ (Test Yourself)

1. What 2 structures fuse to form the lip? (MAX + MNP)
2. Between which weeks does lip formation occur? (Weeks 4–6)
3. What 3 muscles are labeled in Figure 18.6? (M = myrtiform nasalis, O = oblique orbicularis, T = transverse nasalis)
4. Why is the nose deformed in cleft lip? (Aberrant orbicularis oris insertion into alar base)
5. What is the normal function of levator veli palatini? (Primary elevator of palate via transverse levator sling)
6. In cleft palate, what changes about the levator? (Runs longitudinally, inserts into bony cleft margin — no sling)
7. What does tensor veli palatini do? (Opens the Eustachian tube)
8. What gene causes Van der Woude syndrome? (IRF6)
9. By what week is the palate normally complete? (Week 12)
10. What is the recurrence risk if one parent has an orofacial cleft? (2–5% for next child)

🏥 Cleft Lip & Palate — Complete Management

Cummings Otolaryngology, Chapter 18 (pp. 190–192)

THE BIG PICTURE FIRST

CL±P management is a lifelong, multidisciplinary undertaking — not a single operation.

1. Speech
2. Hearing
3. Appearance
4. Dental growth and hygiene
5. Psychosocial health

Memory hook: "SHADP" — Speech, Hearing, Appearance, Dental, Psychosocial

THE SURGICAL TIMELINE — Table 18.2

Memory hook — "LPSABRO": Lip → Palate+tubes → Speech → Alveolar bone → Rhinoplasty → Orthognathic

DIAGNOSIS

• 75% detected prenatally by USS at 13–16 weeks gestation
• Isolated cleft palate is harder to detect prenatally (consider fetal MRI)
• After diagnosis → refer antenatally to cleft team
• Post-birth: cleft nurse contacts within first 24 hours
• Feeding: breastfeeding may be possible with help; Haberman bottle (specialized) reduces need to create vacuum — useful as suction is impaired

HEARING LOSS & OME

The Numbers

• 97% of CL±P children have had OME by age 2
• Cause: tensor veli palatini malposition → Eustachian tube dysfunction → OME
• Long-term: Eustachian tube dysfunction persists after palatoplasty → retraction pockets → cholesteatoma risk

Threshold for Treatment (NICE 60)

• Persistent conductive hearing loss (CHL) ≥ 25–30 dBHL associated with OME, OR
• OME affecting developmental, social, or educational status

Treatment Options

• Ventilation tube insertion (grommets) ± hearing aids
• Important: Ventilation tube insertion only after careful ENT/audiology assessment in cleft patients (not routine at time of palate repair anymore — MOMENT trial ongoing)

UK Hearing Screening Schedule

Memory hook: "6M, then 1 through 5, then 10 and 15"

PRESURGICAL ORTHOPAEDICS: NAM

• Form of presurgical infant orthopaedics
• Oral plate + nasal stents attached
• Worn fulltime from as soon after birth as feasible
• Regularly adjusted to alter nasal cartilage shape and columella length
• Goal: reduce cleft severity + move alar cartilages to a more favorable position before surgery
• Evidence: inconclusive overall; some positive results in unilateral CL±P; not routine in UK

LIP REPAIR (3–6 months)

Timing

• UK standard: 3–6 months
• Some centres do neonatal lip repair — no firm evidence of aesthetic or functional benefit

Goals (same for unilateral AND bilateral):

1. Achieve primary muscle continuity (orbicularis oris sling reconstruction)
2. Reconstruct lip elements to give a symmetrical Cupid's bow
3. Minimum scarring

Techniques

• Millard repair (and its modifications) — most widely used
• Fisher repair — two most commonly practised in UK
• Bilateral cleft lip is more severe; challenges include achieving muscle continuity across the premaxilla; lip adhesion (taping lateral lip segments to premaxillary segment) may be used pre-operatively

Memory hook: "MF for lips" — Millard and Fisher are the two UK lip repair techniques.

PALATE REPAIR (9–12 months)

Two components:

Hard Palate

• Trade-off: Early closure → better speech BUT delayed closure → better facial growth
• UK practice: close hard palate with a vomerine flap at time of lip repair in complete CL±P; OR close with soft palate repair in isolated cleft palate

Soft Palate (Palatoplasty)

• Both have good speech outcomes
• No difference in audiological outcomes between the two
• Both can be offered; surgeon preference determines choice

• LP = Levator palatini
• PP = Palatopharyngeus
• TP = Tensor palatini

Memory hook: "IS FZ" — Intravelarveloplasty = Sommerlad; Furlow = Z-plasty

ALVEOLAR BONE GRAFTING (8–10 years)

Purpose

• Stabilize the alveolar arch
• Allow eruption of the lateral incisor and canine into optimal position

Timing Rule (Critical)

• Timed by development of the canine tooth (not by age alone)
• Secondary bone grafting (age 9–11): No detrimental effect on facial growth ✅
• Primary bone grafting (before 2–3 years): Associated with significant growth impairment ❌ — avoid

Memory hook: "Wait for the canine" — secondary graft only, after canine development begins.

SPEECH & VELOPHARYNGEAL INSUFFICIENCY (VPI)

What is VPI?

• Palate cannot seal against posterior pharyngeal wall → nasopharynx stays open during speech
• Results in: nasal emission + hypernasal speech
• ~20% of cleft palate children have persistent speech disorder after surgery (worst intelligibility category)

VPI incidence

• Submucous cleft: 1 in 1500 to 1 in 3000
• Stigmata of submucous cleft: bifid uvula + zona pellucida + hard palate notch
• Post-adenoidectomy VPI: resolves spontaneously in 50% of cases

Assessment of VPI

Treatment of VPI

• Midline flaps from posterior pharyngeal wall
• Medial transposition of lateral pharyngeal wall flaps
• Both improve speech; both carry OSA risk — must counsel patient/family pre-op

Memory hook: "Small gap → Palate re-repair; Big gap → Pharyngoplasty (but warn about snoring)"

NASAL SURGERY

• Primary goals: aesthetics + nasal airflow
• Cleft nose features: asymmetric nasal tip, deviated septum, asymmetric nasal bones
• Timing controversy:
  • Definitive rhinoplasty traditionally reserved until adolescence (completed facial skeletal growth)
  • Evidence shows primary rhinoplasty (at time of lip repair) can achieve stable long-term results with limited growth disturbance

KEY POINTS (from text)

• Clefts are common congenital birth anomalies
• Aetiology is multifactorial — maternal smoking, alcohol, anticonvulsants
• Prenatal screening is routinely available in many centres
• Management requires a multidisciplinary approach
• OME is a significant problem — further research required (MOMENT trial)

MASTER MEMORIZATION FRAMEWORK

The "CLEFT TIMELINE" Chant

"3 months Lip, 9 months Palate, 4 Speech, 8 Bone, 15 Nose, 16 Jaw"

The "SHADP" Domains

Speech · Hearing · Appearance · Dental · Psychosocial

The "VPI Chain"

Palate fails to close → nasal emission → assess with nasendoscopy → small gap = re-repair palate → large gap = pharyngoplasty → warn about OSA

The "OME Rule of 97/25/6months"

97% get OME → treat if CHL ≥ 25 dBHL → first hearing screen at 6 months

SELF-QUIZ — Test Yourself

1. At what age is primary lip repair done in UK? (3–6 months)
2. At what age is palate repair done? (9–12 months)
3. What is NAM and is it evidence-based in the UK? (Nasoalveolar moulding; inconclusive evidence; not routine in UK)
4. Name the two UK lip repair techniques. (Millard + Fisher)
5. What is the trade-off with hard palate repair timing? (Early closure = better speech; delayed = better facial growth)
6. Name the two palatoplasty techniques and their key differences. (Intravelarveloplasty/Sommerlad = recreates levator sling by radical dissection; Furlow = double opposing Z-plasty, posterior repositioning)
7. Why wait until 9–11 years for alveolar bone graft? (No growth impairment; timed to canine tooth development)
8. What % of cleft children get OME by age 2? (97%)
9. What is the threshold for treating OME? (CHL ≥ 25–30 dBHL or affecting development)
10. What are the 3 stigmata of submucous cleft palate? (Bifid uvula + zona pellucida + hard palate notch)
11. What is the main risk of pharyngoplasty? (Obstructive sleep apnoea)
12. What % of post-adenoidectomy VPI resolves spontaneously? (50%)
13. What feeds are used for cleft babies who cannot suckle? (Haberman bottle — reduces need for vacuum creation)
14. Name all 9 MDT members. (Cleft surgeon, ORL, paediatric dentist, specialist nurse, SALT, psychologist, audiologist, orthodontist, geneticist, paediatrician)