KEY NOTES CHAPTER 4: BREAST AND CHEST WALL - Chest Wall Reconstruction.

Question 0

What are pectus deformities?

Answer 0

• ~1 in 300 live births
• Result from rib cage overgrowth ->
∘ Pectus excavatum (concave chest).
∘ Pectus carinatum (convex or pigeon chest).

Question 1

What are the indications for chest wall reconstruction?

Answer 1

∘ Tumour resection
∘ Infection
∘ Radiation injury
∘ Trauma.

Question 2

What is pectus excavatum?

Answer 2

• Most common congenital chest wall anomaly.
• Sternum displaced posteriorly
• M:F = 3:1.
• Associated with scoliosis and Marfan’s syndrome, pulmonary or cardiac compromise (surgery may improve ejection fraction but not lung function).

• Surgery:
∘ Ribcage reconstruction.
∘ Insertion of a prosthetic moulage.

Question 3

What types of pectus excavatum reconstuction do you know of?

Answer 3

• Nuss repair (1988)
1. Small incisions in lateral chest wall.
2 A shaped convex metal bar is inserted subcutaneously up to sternum, then retrosternally (under video thoracoscopic guidance), then re-enters subcutaneous plane
3. Bar is flipped over
∘ Results in sternal elevation with subsequent remodelling of ribs and costal cartilages.
∘ Not effective in adults
• Ravitch procedure (1949)
• Sternal turnover
Custom-made prosthesis (subcut).

Question 4

.

Answer 4

2500 live births; M:F = 4:1.
∘ Non-operative management with a brace.
- Worn 14 hours a day for 2 years; provides continuous AP compression.
- Progressively remodels chest.
∘ Operative management by modifications of the Ravitch or Nuss procedure.

Question 5

What is Poland’s syndrome?

Answer 5

Alfred Poland (1841) anatomy demonstrating at Guy’s Hospital originally described:

• absent sternocostal pectoralis major (intact clavicular origin),
• absence of pectoralis minor,
• hypoplastic serratus anterior and external oblique.

Question 6

What are the clinical features?

Answer 6

Characterised by unilateral chest wall and upper limb abnormalities.
• Variable manifestation
• 1 in 30,000, usually sporadic.
• M:F 3:1
• R>L
• ? developmental anomaly of subclavian artery in 6th week.
• Associated with Möbius and Klippel-Feil syndromes.

Question 7

What are the chest wall and upper limb abnormalities?

Answer 7

Chest wall
• Absent sternocostal head of pectoralis major
• Absent / hypoplastic breast and NAC (displaced superiorly).
• Lack of subcutaneous fat and axillary hair.
• Abnormalities of pectoralis minor, infraspinatus, supraspinatus, LD, serratus anterior, external oblique and rectus abdominis.
• Abnormalities of rib cage +/- lung herniation.

Upper limb
• Short arms
• Brachysyndactyly.

Question 8

How is breast asymmetry treated?

Answer 8

• Adolescents: tissue expander/implant.

Female
• Once breast development is complete, expander can be replaced with:
1. Definitive implant covered + LD flap or ADM.
2. Autologous tissue:
- Pedicled ipsilateral LD or free contralateral LD.
- TRAM/DIEP flap.
- Lipomodelling.

Male
• LD: recreate anterior axillary fold and mask infraclavicular hollow.
∘ humeral insertion is detached and sutured more
anteriorly on bicipital groove.
• Contralateral costal grafts for absent ribs.
• Custom made subcutaneous silicone implant

Question 9

What are the risk factors for sternal wound infection?

Answer 9

1 Superficial infection: skin, subcutaneous tissue and pectoralis fascia.
∘ systemic antibiotics.

2 Deep infection = mediastinitis
1-5% of median sternotomies.
∘ aggressive surgical debridement and flap coverage.

• Risk factors:
∘ Diabetes
∘ Obesity
∘ COPD
∘ Osteoporosis
∘ Smoking
∘ Use of bilateral internal mammary arteries
∘ Revision operations
∘ Prolonged ITU

Question 10

How is sternal infection classified?

Answer 10

Pairolero

Type I
∘ ~1 week after sternotomy.
∘ Serosanguinous discharge no cellulitis, costochondritis
or osteomyelitis.
- iv antibiotics +/- single-stage operation.

• Type II
∘ 2-4wks
∘ Purulent mediastinitis, osteomyelitis ± costochondritis.
- Debridement, removal of FBs. Dead space obliteration with soft tissue flap.

• Type III
∘ months to years
∘ chronic sinus, costochondritis, osteomyelitis, retained FBs.
- Repeated debridements + flaps.

Question 11

What are the indications for definitive surgical treatment?

Answer 11

Factors predicting need for surgical intervention:
∘ Bacteraemia
∘ Wound depth >4 cm
∘ Bone exposure
∘ Sternal instability.

Question 12

What is a good adjunct to surgical debridement?

Answer 12

NPWT
∘ Increased local blood flow.
∘ Decreased bacterial count.
∘ Enhanced granulation tissue formation.
∘ Chest stabilisation and improved respiratory function.

Question 13

What is the treatment for types 2 & 3 sternal infections?

Answer 13

Surgical debridement
Remove sternal wires
Micro samples

Dead space management:

1. Pectoralis major flap.
   - Turnover: IMA perforators.
   - Rotation advancement: pectoral branches of TA axis, +/- ant rectus sheath to cover inferior sternum.
2. Rectus abdominis flap (muscle / myocutaneous).
   • Supplied by superior epigastric artery (may be compromised if IMA’s used for CABG) or 8th intercostal artery.
3. Omental flap + SSG.
   • Based on either gastro-epiploic pedicles.

Question 14

When is chest wall reconstruction indicated after tumour ablation or trauma?

Answer 14

• chest wall defects >5 cm, or
• segmental loss of four contiguous ribs

Need to consider skeletal support and soft tissue cover.

Question 15

What can be used for skeletal support?

Answer 15

Autologous tissue
• Split rib grafts
• Iliac crest
• Fibula.

1. Alloplastic materials
   ∘ Induces fibrovascular infiltration with incorporation into surrounding tissues.

Mesh and composite implants

(a) Polypropylene knitted mesh (permanent).
- Marlex®: Single-knit (expandable in one direction, rigid in another).
- Prolene®: Double-knit (expandable in both directions).
(b) Polyester: Mersilene®, Dacron®.
(c) Polyglycolic acid: Dexon®.
(d) Expanded polytetrafluoroethylene (e-PTFE): Gore-Tex®.
(e) Polydioxanone: PDS®.
(f) Polyglactin: Vicryl®.

• Composite techniques
∘ Polypropylene mesh and polymethylmethacrylate (PMMA):
- Mesh is cut generously, leaving excess to secure construct to defect.
- PMMA is added to fill defect.
- A 2nd layer of mesh added
- Protect vital structures from heat of PMMA as it sets.

2. Biologic materials: allografts or autografts.
   - Gradually revascularised and remodelled into autologous tissue.
   - More resistant to infection, better for irradiated wounds.

Allografts (human ADM)
(a) AlloDerm®: processed human dermis (not available in UK).
- Cellular components removed, extracellular
matrix and basement membrane preserved.

Xenografts

• Porcine
  (a) Permacol® - crosslinked ADM.
  (b) Strattice® - non-crosslinked ADM.
  (c) Surgisis® - small bowel submucosa.
• Bovine
  (a) Tutopatch® - pericardium.
  (b) Veritas® - pericardium.
  (c) Surgimend® - non-crosslinked ADM.

Question 16

What soft tissue cover options are there?

Answer 16

• Pectoralis major
• LD
• Rectus abdominis
• External oblique (rare)

Local FC / perforator flaps.
Omentum

Question 17

What are the indications for free tissue reconstruction of chest wall defects?

Answer 17

∘ Salvage after the failure of pedicled flaps.
∘ Large defects unreconstructible with pedicled flaps, particularly after radiotherapy.
∘ Defects inaccessible to pedicled flaps.
∘ Intrathoracic deadspace.

FLAPS
∘ TFL
∘ LD
- Including serratus anterior on the same pedicle allows coverage of large defects.
∘ TRAM, VRAM or DIEP
∘ ALT +
- fascia lata for support and vastus lateralis for bulk.
∘ Scapular and parascapular flaps
- Supplied by the circumflex scapular artery, a branch of the subscapular artery.
- Gives a transverse cutaneous scapular branch and vertical parascapular branch.

Question 18

What may cause posterior trunk defects?

Answer 18

Congenital
- Spina bifida

∘ Acquired

• Trauma
• Iatrogenic, following spinal instrumentation
• Tumour
• Pressure ulcer.

Question 19

What flap options are available?

Answer 19

Cervical
1. Trapezius flap
∘ muscle or myocutaneous.
∘ Superficial branch of transverse cervical artery, from thyrocervical trunk.
∘ Superior muscle fibres are left intact to avoid ‘drop shoulder’.

Upper thoracic
• LD flap
• Trapezius flap (posterior i.c. perforators, but LD better)
• Scapular or parascapular flap

Lower thoracic
• LD flap
• Intercostal artery perforator flaps (small)
• Omentum (rare)

Lumbar
• Lumbar artery perforator flap
∘ superseded transverse lumbosacral flap (random pattern).
• SGAP flap
• LD flap (based on segmental supply; may not reach inferior lumbar defects).
• Omentum.