9. Reconstruction

Question 1

Define:
osteoconduction
osteoinduction
osteogenesis

Answer 1

Osteoconduction: graft material acts as a scaffold for vascular tissue and mesenchymal cells

Osteoinduction: stimulation of osteoprogenitor cells to differentiate into new bone forming cells (osteoblasts)

Osteogenesis: transfer of vital osteoblasts to contribute to the growth of new bone

Question 2

Define:
Allograft
Autograft
Xenograft
Alloplastic graft

Answer 2

Allograft: derived from same species. Can provide osteoconduction and osteoinduction

Autograft: graft obtained from the same individual. Provides osteoconduction, osteoinduction, and osteogenesis.

Xenograft: graft from a species that is non-human. Provides osteoconduction

Alloplastic graft: graft from synthetic materials

Question 3

What is creeping substitution?

Answer 3

Process by which osteoclastic activity creates new vascular channels with osteoblastic bone formation resulting in new haversian systems and osteogenesis from the graft.

Question 4

How much bone is available from a tibial bone graft?

What are its indications?

Answer 4

25mL of cancellous bone, 1x2cm cortical block

alveolar cleft grafting, sinus elevation, and socket grafting

Question 5

Approach to the tibial bone graft

Answer 5

There is a medial approach and a lateral approach. Lateral is most common:

• Knee partially flexed, prepared in sterile fashion.
• Local anesthetic
• 2cm incision over palpable ridge of Gerdy’s tubercle through skin and subcutaneous tissue down to periosteum.
• Incise periosteum and a small portion of anterior tibialis muscle inferiorly and fascia lata superiorly will be stripped to allow access to cortex
• Fissure bur under copious irrigation to make 1.5-2cm circular corticotomy, remove with osteotome
• Curette cancellous bone (insert transversely across tibia in downward direction (avoid perforating subchondral bone at superior edge of tibia and violating the knee joint).
• Graft compacted in 10mL syringe (higher amount of fat compared to iliac cancellous grafts).
• Bovine microfibrillar collagen (Avitene) or absorbable gelatin sponge (Gelfoam) can be placed into harvest site.
• Wound closed in layers with dry sterile dressing.

Question 6

Calvarial bone graft indications

Answer 6

No cancellous bone. Use as cortical onlay or bone mill for particulate. Good for ridge augmentation but also orbital and craniofacial reconstruction.

Rapid revascularization and limited resorption that allows for resistance to remodeling and soft tissue displacement.

Limited morbidity and donor site deformity as well as donor site proximity to the recipient site.

Question 7

Location for calvarial bone graft

Answer 7

Several regions available, most common is parietal region. Skull is thickest here (6.3mm) and does not overlay dural sinuses or arteries.

No major nerves in the area. Parietal scalp is hair bearing for scar camouflage.

Superior sagittal sinus runs 5mm parasagittal to the midline (stay 2cm away from midline and 2cm away from thin squamous portion of temporal bone inferiorly.

Question 8

Surgical technique for calvarial bone graft

Answer 8

Parietal bone is accessed by either coronal incision with wide elevation of the scalp or through linear incision directly over the donor site.

• Local
• Incision through Skin, subCutaneous tissue, Aponeurosis, Loose areolar connective tissue, Pericranium.
• Raney clips
• Periosteal elevator in sub pericranial plane
• Fissure bur with copious irrigation to outline desired graft through the outer table. Bevel margin to facilitate curved osteotome placement
• Separate graft from donor bed with osteotomes
• Bone wax for bleeding control. Fill defect with hydroxyapatite or titanium mesh to avoid post harvest deformity (not always required).
• Close wound in layers (approximate galea aponeurosis as this will decrease scar width.

Question 9

How much bone can be harvested from the anterior iliac crest?

Answer 9

Maximum of 50cc of uncompressed cancellous bone (up to 5cm defect). Corticocancellous block also available.

Question 10

Most common nerve encountered during anterior iliac crest harvest?

Other nerves in consideration?

Answer 10

Most common: lateral cutaneous branch of the iliohypogastric nerve (L1, L2), which courses over the tubercle of the ilium. Damage causes sensory disturbance over lateral anterior third of the ilium.

Lateral cutaneous branch of the subcostal nerve (T12, L1) courses over ASIS passing just inferior to iliohypogastric nerve

Lateral femoral cutaneous nerve (L2-3) is most inferior and courses medially between psoas major and iliacus, deep to the inguinal ligament and perforates TFL to innervate lateral skin of thigh. In 2.5% of people, this nerve courses within 1cm of ASIS placing it at risk during inferior dissection. Damage to this nerve can result in meralgia paresthetica (dysesthesia and anesthesial of the lateral thigh).

Question 11

Most common source of bleeding during anterior iliac crest harvest

Answer 11

Superior gluteal artery (internal iliac system).

Question 12

Surgical technique for anterior iliac crest graft

Answer 12

Supine, elevate hip, retract skin medially (so resulting scar ends up lateral to crest)

Mark incision 4-6 cm in length 1-2cm anterior to tubercle of ilium and 1cm posterior to ASIS. Infiltrate with local w/ epi.

Incision oblique along ant iliac crest (avoid iliohypogastric and subcostal nerves which are superior and lateral femoral cutaneous which is inferior-medial.

Incision through skin, subq, Scarpa’s fascia, and muscular aponeurosis.

Plane is between TFL (laterally) and external oblique/transverse abdominus (medially) to iliac crest periosteum (sharply transect).

Iliacus sharply dissected from medial surface for medial approach 5cm deep.

Graft harvest can be clamshell, trapdoor, Tschopp, Tessier, or Trephine technique.

Bone wax or microfibrillar bovine collagen can be used to aid in hemostasis. Low suction drain may be placed to prevent hematoma. Close in layers.

Question 13

How much bone can be harvested from a posterior iliac crest?

Answer 13

Up to 100cc of uncompressed bone available (up to 10cm defect).

Question 14

Regional anatomy posterior iliac crest harvest

Answer 14

Superior cluneal nerve (L1-3) pierces lumbodorsal fascia, travels superior to posterior iliac crest and provides sensation to posterior medial buttocks.

Middle cluneal nerve (S1-3) traverses through sacral foramina and innervates the medial buttocks

Sciatic nerve (L4-5, S1-3) is 6-8 cm below the posterior iliac crest and should not be encountered

Blood supply is perforators from the subgluteal artery.

Question 15

Surgical technique for posterior iliac crest harvest

Answer 15

Prone position, 210 degree reverse hip flexion.

6-10cm curvilinear incision following posterior iliac crest. End 3cm lateral to gluteal crease.

Incision skin, subcutaneous tissue, lumbodorsal fascia (separates abdominal and gluteal musculature), and periosteum over posterior iliac crest.

Gluteus maximus muscle is stripped from tubercle using blade or electrocautery against cortical bone.

5x5cm posterior iliac crest osteotomy of lateral cortical plate to access cancellous bone. Limit harvest at least 4cm from PSIS to avoid violation of sacroiliac joint.

Bone wax or microfibrillar bovine collagen for hemostasis. Close in layers. Drain placed.

Question 16

Anterolateral Thigh Flap
- Vascular supply
- Regional anatomy
- Use

Answer 16

ALT is a fsciocutaneous perforator flap based on descending branch of the lateral circumflex femoral artery.
- Runs in the intermuscular septum between rectus femoris and vastus lateralis
- Long vascular pedicle length 8-16cm
- Fairly thick flap
- can be raised with only fascia without skin (thinner)
- Versatile
- Donor site can be closed primarily (minimal donor site morbidity)

Question 17

Surgical technique for anterolateral thigh flap (ALT)

Answer 17

Draw line from anterior-superior iliac crest to lateral aspect of patella (corresponds to intermuscular septum between rectus femoris and vastus lateralis)
- At midpoint of line, 5cm circle. Within this circle is where the perforating vessels can be identified. Flap designed over the perforator.
-Skin incision along medial margin of flap (skin, subq, fascia over rectus femoris muscle)
- In subfascial plane, gentle blunt dissection laterally until perforating vessels are identified
- Once perforator is identified, intermuscular septum between vastus lateralis and rectus femoris is dissected and flap pedicle can be identified
- Pedicle traced back to takeoff from lateral circumflex femoral artery.

Question 18

ALT components, pedicle length/caliber, and indications

Answer 18

ALT

Skin, muscle (vastus lateralis), fascia. Large flap up to 10 x 25 cm can be harvested.

Pedicle 5-7cm in length with 1.5-3mm vessel (descending branch of the lateral femoral circumflex artery).

For large facial or intraoral defects, scalp defects, orbitocraniofacial resections, gunshot wounds. May be too thick in obese patients.

Question 19

Radial forearm free flap
- Vascular supply
- Regional anatomy
- Use

Answer 19

RFFF is a fasciocutaneous flap based off the radial artery.
- Venous outflow is by the venae comitantes or cephalic vein
- FOM, tongue, lip, and buccal mucosa reconstruction. (Defects requiring more bulky tissue such as subtotal glossectomy and large skull base tumors are better suited with bulkier flap such as ALT).
- Long vascular pedicle, large caliber vessels allow for easy anastomosis.

Question 20

Preoperative considerations for RFFF

Answer 20

“No stick” order for patients presenting for reconstruction

Use non-dominant hand

Pre-operative Allen test to make sure there is adequate ulnar collateralization. Compress ulnar and radial arteries, release ulnar artery.

Question 21

RFFF harvest technique

Answer 21

RFFF

Palpate radial artery and mark, mark cephalic vein. Draw appropriate sized flap over radial and volar surface of the forearm.

Tourniquet 250mmHg

Flap elevation - 15 blade at distal aspect of segment - skin, subq, fascia. Dissect cephalic vein and radial artery and radial artery venae comitantes.

Elevate flap in subfascial plane. Ligate and divide radial artery and two venae comitantes as well as cephalic vein.

Closure with primary closure of releasing incision and skin graft over flap donor defect (split thickness skin graft from thigh), perforated with bolster.

Question 22

Radial forearm free flap components, pedicle length/caliber, and indications

Answer 22

RFFF

Skin and fascia. Tendon (pulmaris longus) if suspension is needed. Bone (radius) if small bone is required).

Long pedicle if taken at take-off from bracheal artery. Large caliber 2-4mm with two venae comitantes or cephalic vein for drainage.

Thin flap great for intraoral soft tissue defects or tongue reconstruction or lip reconstruction if tendon is included.

Question 23

Fibula free flap vascular supply, regional anatomy, and use

Answer 23

Fibula free flap
Excellent option for reconstruction of mandible defects (from neoplasm, osteonecrosis, and trauma). For composite osseous defects that require reconstruction of adjacent oral lining or external skin.

Peroneal artery (PA) and its venous comitantes provide vascular supply.

Bone height 9-15mm with total length of 35cm (typically up to 25cm can be harvested)

Question 24

Fascial compartments of the lower leg

Answer 24

Compartments are dictated by the tibia and fibula bones as well as fascial planes.

Tibia and fibula with their interosseous septum separate anterior and posterior compartments. Anterior lower leg is further subdivided into anterior and lateral compartments by the anterior intermuscular septum. Posterior lower leg is subdivided into deep and superfical compartments by the transverse intermuscular septum.

The lateral and posterior compartments are separated by the posterior intermuscular septum which carries the skin perforator vessels essential to skin paddle harvest.

Question 25

Imaging in pre-operative workup for fibula free flap

Answer 25

1. Magnetic Resonance Angiography
2. Computed Tomographic Angiography
3. Conventional Angiogram
4. Color-Flow Doppler Imaging (may also play a role in localizing perforators).

Question 26

Variation in Arterial Supply of lower leg

Answer 26

Surgically significant anomolies occur in 10% of population, 5.2% of any given limb.

Infra-popliteal arterial branching classification (Kim-Lippert’s)
I: normal level of branching
II: high-division of PA (at or above the knee)
III: (10.37% overall) Hypoplastic/aplastic branching with altered distal supply
IIIA: 2-vessel runoff, deficient vessel PT (63%)
IIIB: 2-vessel runoff, deficient vessel AT (29%)
IIIC: single vessel runoff (peronia arteria magna), deficient vessel both tibial arteries (8%)
IV: PA vessel caliber variation
IV-A: hypoplastic (not recommended, but may not fully preclude FFF harvest given anastomoses of vessels as small as 1mm possible)
IV-B: aplastic (absolute contraindication)

Question 27

Fibula Free Flap components, pedicle length/caliber, indications

Answer 27

FFF

Bone, muscle (flexor hallucis longus cuff or adjacent soleus muscle), and skin

Pedicle length depends on the length of bone needed but can be 5+ cm, 2-4mm diameter vessel, peroneal artery, and venae comitantes

Used for maxillary or mandibular reconstruction, can use closing osteotomies to establish arch form

Question 28

Scapula free flap components, pedicle length/caliber, and indications

Answer 28

Scapula free flap

Skin and bone (lateral border of scapula). Pedicle up to 7cm length, 2-4mm vessel diameter, subscapular artery.

Used for mandibular ramus reconstruction and maxillary reconstruction.

Question 29

Deep Circumflex Iliac Artery (DCIA) free flap components, pedicle length/caliber, and indications

Answer 29

DCIA

Vascularized iliac crest bone, iliacus muscle, with or without skin.

Pedicle 4-8cm length, 1.5-3mm diameter vessels, deep circumflex iliac artery and venae comitantes.

Used in maxillary or mandibulr reconstruction, may require vein grafts if inadequate pedicle length.

Question 30

Fibula free flap technique

Answer 30

Exsanguinate leg with compressive bandage, apply thigh tourniquet 250-350 mmHg.

Long anterior curvilinear incision to transverse intermuscular septum.

Locate perforators to the skin. Dissect along length of anterior aspect of fibula via elevation of peroneus longus, peroneus brevis, and extensor hallucis longus. Continue dissection along bone to medial aspect reveals interosseous membrane.

Proximal and distal fibular bone cuts (at least 6-8cm preserved on both ends to preserve knee and ankle stability. Retract fibula laterally to expose interosseous membrane, which is transected to separate fibula from tibia and expose peroneal pedicle below membrane.

Distal peroneal artery and veins are identified after distraction of fibula. Ligate and transect distal pedicle.

Question 31

Recipient vessels for microsurgery in the upper face and scalp

Answer 31

Superficial temporal artery and vein

Question 32

Recipient vessels for oral cavity and lower facial reconstruction

Answer 32

Facial artery and vein or external jugular vein

Question 33

Which recipient arteries can be used if the facial artery is not acceptable?

Answer 33

Lingual and superior thyroid artery

Transverse cervical artery at base of neck if no other superior options are available

Question 34

Most common cause of vascular failure of a flap

Answer 34

Venous congestion vs. arterial thrombus (4:1)

Question 35

After ___ hours of ischemia, free flap salvage is not possible.

Answer 35

12 hours.

Hourly checks for first 24 hours
2 hour checks for next 48 hours

Question 36

How does aspirin work to reduce thrombotic complications?

Answer 36

Aspirin blocks thromboxane A2 production that has vasoconstrictor activity and aids in platelet binding.

Started immediately after surgery and commonly continues 30-90 days

Question 37

How does heparin work to reduce thrombotic complications

Answer 37

Heparin binds to antithrombin III which causes increased activity, preventing activation of factor IIa, XIIa, IXa, and Xa.

Not typically utilized after free flap due to risk for bleeding and hematoma formation which can have devastating effect.

Heparin irrigation is commonly used as vessel irrigant.

Question 38

Earliest signs of flap vascular congestion

Answer 38

Increased turgor or faint bruise within flap.

Progresses to diffuse and dark ecchymosis.

Doppler signal will remain normal or near normal until late stages of congestion.

Flap color and character of bleeding on pin prick are perhaps the most important tools in diagnosis of vascular compromise in the postoperative period.

Question 39

Methods of flap evaluation

Answer 39

Clinical: pinprick, surface temp (difference 3C associated with arterial insufficiency and 1-2C with venous insufficiency), capillary refill, turgor of tissue, serial photography.

Doppler: internal, external, and laser

Pulse oximetry: commonly quoted, best to monitor digit

Question 40

How is the pinprick test used to monitor flaps?

Answer 40

Medium gauge needle used to pierce flap

Arterial occlusion = minimal to no bleeding. Turgor of tissue is decreased due to lack of inflow of blood.

Venous occlusion will cause rapid bleed of dark blood. Turgor of tissue is increased due to inability to clear venous blood.

Question 41

Indications for tracheostomy

Answer 41

• Need to bypass upper airway
• Patients who require prolonged intubation (encephalopathy due to trauma or cerebrovascular disease).
• Protects laryngeal tissues and trachea from prolonged intubation, facilitates pulmonary physiotherapy and suctioning. Allows for weaning of sedation.
• Severe sleep apnea.

Question 42

Technique for tracheostomy

Answer 42

Extend patient’s neck
Identify thyroid notch, cricoid cartilage, bilateral SCMs, and sternal notch (mark these)
Transverse incision half-way between sternal notch and cricoid cartilage
LA w/ epi
Incision to subq, blunt dissection, divide SLDCF vertically taking care not to damage anterior jugular veins and branches (retract laterally or ligate)
Strap muscles encountered, divide median raphe between infrahyoid strap muscles and retract laterally
Thyroid isthmus often encountered and can be retracted cephalad or ligated and divided
Trachea visualized, pretracheal fascia divided
Anesthesia deflates cuff to avoid rupture
Transverse incision through trachea between 2nd and third tracheal rings. Heavy scissor used to transect rings inferior
Endotracheal tube is slowly withdrawn and tracheostomy tube is inserted
Confirm chest rise, EtCO2, Bilateral breath sounds
Secure tracheal tube.

Question 43

Bleeding source during tracheostomy

Answer 43

Anterior jugular vein or inadequate control of highly vascular thyroid.

Avoid excessive electrocautery (recurrent laryngeal nerve travels in area of tracheoesophageal groove).

Bipolar cautery used.

Question 44

Pectoralis Major Myocutaneous flap
- Use
- Vascular supply

Answer 44

Pectoralis Major Myocutaneous Flap
- Reconstruct soft tissue defects of oral, oropharyngeal, skull base, esophageal, partial tracheal, and pharyngeal defects.
- Cover exposed major vessels and cutaneous defects of the neck
- Pectoral branch of throacoacromial artery, lateral thoracic artery, superior thoracic artery, and intercostal artery
- Venous drainage via venae comitantes into axillary vein
- 6 x 6cm flap in men without need to skin graft. This can be doubled in females.

Question 45

Pectoralis Major Myocutaneous Flap
Technique

Answer 45

Incision through skin/subq on lateral aspect of incision
Dissection to pectoralis fascia
Curvilinear extension of flap is dissected laterally toward free margin of pec major muscle
Elevate between pec major and minor
Pectoral nerves released to aid in arc of rotation
Lateral attachment to humeral insertion is released
Tunnel created to head and neck (subplatysmal plane of dissection over clavicle
Flap inset
Chest closed in layers (skin graft if needed)

Question 46

Temporoparietal Fascia Flap
- Use
- Vascular Supply

Answer 46

Orbital, auricular, and maxillary reconstruction
Can be harvested with cutaneous tissue (skin/forehead) or cranial bone
- Superficial temporal artery and vein

Question 47

Temporoparietal fascia flap technique

Answer 47

ID superficial temporal artery
Incision through preauricular crease and extending superficially into a hemi-coronal incision
Dissect through subcutaneous fat
Anterior extension to safe length to expected course of the frontal branch of the facial nerve. Superiorly extension is carried to the vertex of the scalp.
Check arc of rotation with suture.
Release fascia with desired pedicle
Release is completed in the subgaleal areolar tissue down to zygomatic arch.
Subcutaneous tunnel formed to allow extension of flap to defect without pressure.

Question 48

Paramedian flap/median forehead flap
-Use
-Vascular supply
-Technique

Answer 48

Color of forehead makes great match for face and nose
- Can incorporate supratrochlear artery as part of flap (2cm from mid glabella, emerging from supratrochlear foramen)

The median forehead flap is designed to capture both supratrochlear arteries while the paramedian flap is aligned vertically over the supratrochlear notch to capture single side.

Flap raised in supraperiosteal plane to include skin, subq, frontalis muscle. Flap width should be 1.5cm. Forehead closed primarily. Division is done at 3 weeks.

Question 49

Melolabial Flap/nasolabial flap
- Use
- Vascular Supply
- Technique

Answer 49

Cutaneous flap harvested from skin lateral to melolabial crease; can be harvested with superior or inferior base.

Superior flaps for reconstruction of nasal, palatal, or oral sulcular defects
Inferior flaps for lip, floor of mouth, and buccal mucosa defects

Good color match for lips and nose.

Branches of facial artery (drained by facial angular artery). Facial artery runs deep to the mimetic muscles.

Incision 1-2mm lateral to melolabial fold to prevent flattened appearance. Most commonly used for cutaneous reconstruction. Rotated into place and divided 3 weeks later.

Question 50

Facial Artery Musculomucosal Flap (FAMM flap)
- Use
- Vascular Supply

Answer 50

Can be based superiorly or inferiorly based on the facial and angular arteries
- Inferiorly (anterograde flow) best for floor of mouth, tongue, gingival, alveolar, and lower lip reconstruction
- Superiorly (retrograde flow) best for palate, skull base, conjunctiva, intranasal lining of nose, nasal septum, and upper alveolar defects

Up to 2cm wide but must take into consideration Stensen’s duct
Division at 3 weeks

Question 51

Tongue flap
- Use
- Vascular supply

Answer 51

Random or axial flap
Axial flap based off the dorsal-lingual branch of lingual artery
Based anteriorly or posteriorly
- Anteriorly: best for anterior floor of mouth, lips, and hard palate
- Posteriorly: best for soft palate, posterior buccal mucosa, and retromolar region

As thin as 3mm
As thick as 10mm (up to 2/3 dorsum of tongue raised to circumvallate papillae.
Designed 20% bigger than defect.

Question 52

Submental Artery Island Flap
- Use
- Vascular Supply

Answer 52

Based off of the submental artery (branch of facial artery), and submental vein

For facial skin, oropharynx, esophageal, nasopharyngeal, floor of mouth, retromolar, soft palate, and tongue defects and maxilla

Good color and texture for cutaneous defects. Good vascularity
Risk of transfer of metastatic nodes at level I.

Question 53

Buccal Fat Pad Flap
- Use
- Vascular Supply
- Anatomy

Answer 53

Composed of three lobes (anterior, intermediate, posterior)
Posterior lobe has four extensions (buccal, pterygoid, pterygopalatine, and temporal)
Fat contains some stem cells
Grafts epithelialize in 4 weeks
Good for small and proximal defects (OAF closure, oncologic defects, cleft palate, drug induced osteonecrosis, and osteoradionecrosis.

Blood supply from buccal and deep temporal branch of the maxillary artery and the superficial temporal artery from the facial transverse branch.

Question 54

Lower lip blood supply and innervation.

Answer 54

Branches of facial artery: inferior labial a, horizontal labial a, vertical labial a.

Sensation from mental branch of inferior alveolar nerve.

Motor innervation from marginal mandibular branch of the facial nerve.

Question 55

Upper lip blood supply and innervation.

Answer 55

Superior labial artery of the facial artery.

Sensation from infraorbital branch of the maxillary division

Question 56

Loss of 50% of one lip results in a ___% decrease in total oral circumference

Answer 56

25%

Question 57

Defects 1/4 of upper lip

Answer 57

Primary closure with V, W, shield, pentagonal incisions. T-excision (bilateral advancement flap. Lose philtrum and cupid’s bow.

Question 58

Abbe Flap

Answer 58

Abbe Flap- cross lip transfer of full thickness lip tissue based on the inferior labial artery. Raise flap, transpose 180*, inset. Donor site is closed. Divide 21 days later.

Question 59

Karapandzic flap

Answer 59

Rotation neurovascular advancement flap, good for 2/3 or subtotal reconstruction of upper or lower lip. Semicircular partial thickness incisions of skin and mucosa. Preserve facial nerve branches, sensory branches of V2 and V3, and superior and inferior labial arteries. Leeds to microsomia (no additional tissue is recruited.

Question 60

McGregor flap

Answer 60

Modification of Gilles. Flap rotated around commissure and transfers tissue from melolabial region which prevents microstomia. Does not restore natural looking vermillion.

Question 61

Stein flap

Answer 61

double abbe flap with preservation of philrum but harvesting on either side of philtrum ( for large defects of lower lip)

Question 62

What flap is used to reconstruct defects of the commissure?

Answer 62

Estlander flap

Question 63

Brown Classification of Maxillary Defects

Answer 63

Class I (loss of alveolus)
Class II (loss of alveolus and malar support)
Class III (loss of maxillary alveolus, malar support, and orbital support)
Class IV (loss of maxillary alveolus, malar support, orbital support, and orbital contents)
Class V, VI
a (midline palate), b (unilateral), c (anterior), d (anterior and posterior)

Question 64

How is a ridge split (inlay bone graft) performed?

Answer 64

2 stage
I. FTMPF, crestal, apical, and two vertical osteotomies with piezo. Close.

II. 4 weeks later, blood supply re-established via periosteum, but callus still present at corticotomies. Crestal incision and osteotomes to outfracture the bone flap. Primary closure (with membrane, as closure is often difficult).

Question 65

Allen’s test
Main blood supply to the hand

Answer 65

Allen’s test is used to assess the circulatory blood flow of the hand.
- Main blood supply to the hand is via the ulnar and radial artery
- Ulnar artery supplies superficial palmer branch
- Radial artery supplies deep palmer branch
- Communication between superficial and deep systems allows perfusion of the hand if there is interruption of one of the two main arteries to the hand

Simulate complete interruption of the radial artery. Elevate hand, digitally occlude both ulnar and radial arteries. Clench fist to cause blanching. Pressure over ulnar artery is released, capillary refill is evaluated.

Question 66

Tongue reconstruction considerations based on size of defect

Answer 66

• Primary closure if it will not restrict tongue mobility
• 33-50% of tongue remaining, use thin, pliable flap (radial fasciocutaneous free flap) to maintain mobility
• <33% of original tongue, reconstruction shifts to restoration of bulk to direct secretions toward the oropharynx and provide contact of the neotongue with palate for deglutition. (Anterolateral thigh flap).

Question 67

Pectoralis flap surgical technique

Answer 67

Curvilinear incision from clavicle inferiorly into parasternal lim, then posteriorly into a horizontal inframammary limb.

Incision down to pectoralis fascia; skin flap laterally in suprafascial plane to expose pectoralis major. Separate sternocostal attachments, blunt dissection over pectoralis minor. Identify pectoral branch of thoracoacromial artery entering the deep aspect of the muscle.

Tunnel is created from chest wall dissection into neck dissection in subplatysmal plane.

Question 68

Dominant pedicle of the pectoralis major myocutaneous flap

Answer 68

Pectoral branch of the thoracoacromial artery

Other supply from internal mammary perforators (secondary segmental pedicles)

Question 69

Blood supply of fibula free flap

Anatomy of associated vessels / source

Between which muscles is this artery located?

Answer 69

Peroneal artery and vein

Peroneal artery originates from the posterior tibial artery after the popliteal artery branches into anterior and posterior tibial arteries

Peroneal artery and its two venae comitantes descend in the lower leg between the flexor hallucis longus and the tibialis posterior.

Question 70

How much bone can be harvested in the fibula free flap?

Answer 70

22-25cm of bone
Leave 6-7cm proximally and distally to maintain adequate stability of the knee and ankle joints.

Question 71

After resection of a mandibular tumor and placement of a locking reconstruction plate, how long should you wait before bone grafting the area?

Answer 71

Minimum of 3 months after ablative surgery is recommended to allow sufficient time for soft tissue healing before bone grafting.

Question 72

Length of defect and non-vascularized graft

Answer 72

Failure rate for non-vascularized grafts of 6cm or shorter is 17%.

This increased to 75% for grafts over 12cm in length.

Question 73

Vascularized vs. non-vascularized grafting of segmental mandibular defects

Answer 73

96% success with vascularized bone grafts
69% success with non-vascularized bone grafts

Failure rate for non-vascularized grafts increases in defects longer than 6cm and extreme caution should be used in using nonvascularized grafts for reconstructing segmental mandibular defects longer than 9cm.

6cm or shorter (17% failure)
12cm or longer (75% failure)

Question 74

Intraoral perforation noted during second stage bone grafting of a segmental mandibular defect

Answer 74

Immediately irrigate wound and close in a double-layer fashion, followed by copious irrigation of the bed with an antibiotic solution (to reduce bacterial load) and redosing the IV antibiotic if sufficient time has passed since the preoperative dose.

Question 75

Posterior iliac crest harvest technique

Answer 75

• Reverse flex prone position
• Palpate posterior-superior iliac spine
• 10cm curvilinear incision 3cm from midline along crest
• Dissection through superficial fat and superficial fascia. Lumbodorsal fascia sharply incised to expose posterior iliac crest and spine and its attachments (medial to lateral: gluteus maximus, latissimus dorsi, external oblique).
• Subperiosteal dissection to reflect gluteus maximus off posterior superior iliac spine and part of gludeus medius from lateral aspect of pelvis.
• Corticotomy along lateral third of iliac crest and including a portion of the posterior-superior iliac spine).

Question 76

Pros/cons of anterior vs. posterior iliac crest bone graft

Answer 76

Posterior: quantity and quality of bone. Increased operating time, inability of two teams to work simultaneously.

Anterior: simultaneously prepare recipient bed and harvest bone graft in two teams. Less bone.

Question 77

Ecchymosis of the flank after anterior iliac crest bone grafting

Answer 77

“Grey-Turner sign” can indicate retroperitoneal bleeding

Question 78

Bone grafting
1. First 3-5 days
2. Days 10-14
3. Weeks 3-4

Answer 78

Bone grafting
1. First 3-5 days: cells survive via diffusion of nutrients from recipient bed (vascularity is important). Can be optimized with hyperbaric oxygen in irradiated patients, added tissue bulk if needed, removal of scar tissue, and absence of infection. Day 3: capillary buds proliferate and begin to penetrate graft to support osteoid production.

2. Days 10-14: completion of vascularization at 2 weeks (stops when oxygen gradient is obliterated).
3. Weeks 3-4: phase I bone (woven bone) regeneration dependent on osteocompetent cellular density of the graft. Phase I bone replaced by Phase II bone (mature lamellar bone).

Question 79

rhBMP

Answer 79

Adjunct therapy - osteoinductive creating bone de novo by recruiting circulating mesencymal cells and initiating their differentiation into functional osteoblasts.

Question 80

PRP

Answer 80

Platelet rich plasma consists of concentrated blood plasma exceedingly rich in platelets.

Platelets once activated with the addition of thrombin and calcium chloride, causes degranulation from the alpha granules to release growth factors, making it ideally suited for augmenting wound healing.

Growth factors, along with cytokines coordinate cellular chemotaxis, proliferation, angiogenesis, provisional matrix formation, epithelialization, and maturation.