Principles of Microvascular Free Tissue Transfer For Reconstruction of the Mandible, Midace, Other Prosthetics

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Principles of Microvascular Free Tissue Transfer For Reconstruction of the Mandible, Midace, Other Prosthetics

Head and Neck Surgery
Author Credentials 

Kelly Michele Malloy, MD
Associate Professor; Director, Head and Neck Surgical Oncology and Microvascular Reconstruction Fellowship
Department of Otolaryngology- Head and Neck Surgery 
University of Michigan
Ann Arbor, MI
kellymal@med.umich.edu

Module Summary

Head and neck ablative surgery imparts significant functional and cosmetic impact on patients. Osteocutaneous free flap reconstruction provides reliable replacement tissues to reconstruct these complicated defects. An understanding of the tissue characteristics and function of the resected organs is essential to proper flap selection and design. Moreover, head and neck surgical wounds can often be complicated by contamination and fistula due to their location within the aerodigestive tract. This module provides the basic anatomy, physiology, pros, cons and complications of bony free flap harvest and reconstruction from which a deeper understanding of bony head and neck reconstruction can be developed.

Module Learning Objectives 
  1. Name the most common free flaps used in bony head and neck reconstruction, including the vascular anatomy and the tissue qualities that each flap provides. 
  2. Apply the appropriate osteocutaneous flap reconstruction to common bony defects of the head and neck.
  3. Diagnose flap-related complications, including vascular compromise, donor site morbidity, and functional consequences. 

Embryology

Learning Objectives 
  1. Name the congenital anomalies that may impact osteocutaneous free flap harvest.
    • Peroneal artery anomalies
References 
  1. Golas AR, Levine JP, Ream J, Rodriguez ED. Aberrant Lower Extremity Arterial Anatomy in Microvascular Free Fibula Flap Candidates: Management Algorithm and Case Presentations. J Craniofac Surg. 2016 Nov;27(8):2134-2137. [EBM Level 5]

Anatomy

Learning Objectives 
  1. Catalogue the available bone free flap armamentarium with respect to:
    • Flap soft tissue characteristics: bulk, pliability and epithelial lining
    • Flap bone characteristics: length, height/width, capacity for implants
    • Neurovascular anatomy
    • Pedicle length
    • Donor site morbidity
    • Availability of a source for nerve grafting
    • Simultaneous two-team harvest
  2. Classify bony flaps by tissue type:
    • Osseous
    • Osteocutaneous
    • Multi-paddle osseous and fasciocutaneous
    • Multi-paddle osseous and myocutaneous
  3. Analyze common defects of the head and neck anatomy with respect to the specific tissue and functions affected:
    • Mandibular defects:
      • Anterior, lateral, angle-to-angle, composite mandubulectomies
      • Concurrent soft tissue needs: glossectomy, floor of mouth, buccal mucosa
    • Maxilla and orbit defects:
      • Infrastructure maxillectomy
      • Total maxillectomy including orbital floor, with orbit preservation
      • Total maxillectomy with orbital exenteration
References 
  1. Urken ML, Cheney ML, Blackwell KE, Harris JR, Hadlock TA, Futran N. Regional and Free Flaps for Head and Neck Reconstruction: Flap Harvest and Inseting. 2nd ed. Philadelphia: Wolters Kluwer, Lippincott Williams & Wilkins; 2012.
  2. Urken ML. Multidisciplinary Head and Neck Reconstruction: A Defect-Oriented Approach. Philadelphia: Wolters Kluwer, Lippincott Williams & Wilkins; 2009.
  3. Neligan PC and Wei FC. Microsurgical Reconstruction of the Head and Neck. New York: Thieme; 2009. 
  4. Genden EM. Reconstruction of the Head and Neck: A Defect-Oriented Approach. New York: Thieme; 2012.

Pathogenesis

Learning Objectives 
  1. Anticipate surgical defects based on pre-operative physical exam and imaging characteristics.
  2. Explain general reconstructive goals for head and neck defects, including functional restoration, durability, optimal aesthetics, limited donor site morbidity, and quality of life enhancement.
  3. Indicate how these goals are accomplished by various reconstructive approaches.
  4. Describe the reconstructive ladder for the following defects:
    • Mandibulectomy
      • Anterior mandible resection
      • Lateral mandible resection
      • Through and through resection (mandible resection with associated mucosal and skin defects)
    • Maxillectomy
      • Infrastructure maxillectomy
      • Total maxillectomy including orbital floor, with orbit preservation
      • Total maxillectomy with orbital exenteration
References 
  1. Urken ML. Multidisciplinary Head and Neck Reconstruction: A Defect-Oriented Approach. Philadelphia: Wolters Kluwer, Lippincott Williams & Wilkins; 2009.
  2. Genden EM. Reconstruction of the Head and Neck: A Defect-Oriented Approach. New York: Thieme; 2012.

Basic Science

Learning Objectives 
  1. Discuss the general principles of sound microsurgical technique
    • Specialized training
    • Microsurgical preparation of donor and recipient vessels
    • End-to-end and end-to-side anastomoses
    • Management of vessel caliber mismatch
    • Pedicle geometry
    • Indications for vein grafts
  2. Distinguish the different elements that contribute to flap vessel thrombosis.
    • Clotting factors
    • Platelets
    • Pedicle kinking or tension
    • Wound contamination from fistula/infection
  3. Explain the concept of ischemia-reperfusion injury and understand the relevance to reconstruction with microvascular free tissue transfer.
References 
  1. Esclamado RM, Carroll WR. The pathogenesis of vascular thrombosis and its impact in microvascular surgery. Head Neck.1999 Jul;21(4):355-62.
  2. Carroll WR, Esclamado RM. Ischemia/reperfusion injury in microvascular surgery. Head Neck. 2000 Oct;22(7):700-13.

Genetics

Learning Objectives 
  1. Understand how genetic clotting disorders can affect free flap management 
  • Hypercoagulable disorders:
  • Proteins C & S deficiencies
  • Factor V Leiden mutation
  • Antiphospholipid antibody syndrome
  • Anticardiolipin antibody syndrome
  • Prothrombin gene mutation
  • Hyperhomocysteinemia
  • Factor VIII elevation
  • Essential thrombocytosis
References 
  1. Wang TY, Serletti JM, Cuker A, McGrath J, Low DW, Kovach SJ, Wu LC. Free tissue transfer in the hypercoagulable patient: a review of 58 flaps. Plast Reconstr Surg. 2012 Feb;129(2):443-53 [EBM Level 4]

Patient Evaluation

Learning Objectives 
  1. Assess patient’s overall health, functional status, comorbidities
    • Tolerance of a long anesthetic event
    • Tolerance of donor site morbidity
    • Vascular health
    • Prothombotic states
    • Dental status and goals for dental rehabilitation
  2. Identify appropriate pre-operative evaluations to assess candidacy for specific free flap donor sites
    • Osteocutaneous radial forearm flap: 
      • Allen’s test
      • Ultrasound with digital pressures
    • Fibula flap:
      • Dorsalis pedis pulses
      • Lower extremity CTA or MRA for 3-vessel run off
    • Scapula:
      • Assess should function
    • Iliac crest:
      • Assess for previous surgery, hernia risk
  3. Explain the importance of nutrition and identify methods to optimize prior to advanced reconstructive surgery.
  4. Predict and prepare for wound healing issues related to previous head and neck radiation, including the impact of radiation-related hypothyroidism.
References 
  1. Benatar MJ, Dassonville O, Chamorey E, Poissonnet G, Ettaiche M, Pierre CS, Benezery K, Hechema R, Demard F, Santini J, Bozec A. Impact of preoperative radiotherapy on head and neck free flap reconstruction: a report on 429 cases. J Plast Reconstr Aesthet Surg. 2013 Apr;66(4):478-82. [EBM Level 4]
  2. Lo SL, Yen YH, Lee PJ, Liu CC, Pu CM. Factors Influencing Postoperative Complications in Reconstructive Microsurgery for Head and Neck Cancer. J Oral Maxillofac Surg. 2017 Apr;75(4):867-873.[EBM Level 4]
  3. Rosko AJ, Birkeland AC, Bellile E, Kovatch KJ, Miller AL, Jaffe CC, Shuman AG, Chinn SB, Stucken CL, Malloy KM, Moyer JS, Casper KA, Prince MEP, Bradford CR, Wolf GT, Chepeha DB, Spector ME. Hypothyroidism and Wound Healing After Salvage Laryngectomy. Ann Surg Oncol. 2017 Dec 20. Epub ahead of print. [EBM Level 4]
  4. Dort JC, Farwell DG, Findlay M, Huber GF, Kerr P, Shea-Budgell MA, Simon C, Uppington J, Zygun D, Ljungqvist O, Harris J. Optimal Perioperative Care in Major Head and Neck Cancer Surgery With Free Flap Reconstruction: A Consensus Review and Recommendations From the Enhanced Recovery After Surgery Society. JAMA Otolaryngol Head Neck Surg. 2017 Mar 1;143(3):292-303. [EBM Level 4]
     

Measurement of Functional Status

Learning Objectives 

Assess patient’s functional age and comorbidity risk using tools such as the American Society of Anesthesiologists (ASA) score, rather than simple chronologic age, when considering microvascular surgery.

References 
  1. Jubbal KT, Zavlin D, Suliman A. The effect of age on microsurgical free flap outcomes: An analysis of 5,951 cases. Microsurgery. 2017 Nov;37(8):858-864. [EBM Level 4]
  2. Ehrl D, Heidekrueger PI, Ninkovic M, Broer PN. Effect of Preoperative Medical Status on Microsurgical Free Flap Reconstructions: A Matched Cohort Analysis of 969 Cases. J Reconstr Microsurg. 2018 Mar;34(3):170-175. [EBM Level 4]

Imaging

Learning Objectives 
  1. Order and interpret appropriate preoperative imaging to assist with operative planning and flap selection:
    • Vascular studies
      • CTA/MRA/ultrasound Doppler studies for arterial assessments
    • CT neck with contrast
      • Anticipate bone flap requirements based on planned resection of primary tumor 
      • Assess vessels for microvascular anastomosis, particularly in revision surgery and/or vasculopathic patients
      • 3-dimensional modeling opportunities for planning of osteotomies
    • CT chest/CTA lower extremity
      • Obtained for metastatic work up and vascular assessment, respectively
      • Allow for evaluation of donor bone sites, scapula and fibula, respectively
      • 3-dimensional modeling opportunities for planning of osteotomies/template approach to bony flap reconstruction
References 

The scholarship in the 3D modeling for mandibular or maxillary reconstruction arena remains quite preliminary, but is expected to evolve in next few years.

  1. Chan HH, Siewerdsen JH, Vescan A, Daly MJ, Prisman E, Irish JC. 3D Rapid Prototyping for Otolaryngology-Head and Neck Surgery: Applications in Image-Guidance, Surgical Simulation and Patient-Specific Modeling. PLoS One. 2015 Sep 2;10(9). [EBM Level 5]

Treatment

Learning Objectives 
  1. Select appropriate bony flap reconstruction for various head and neck defects:
    • Mandible defects: 
      • Fibula
      • Scapula
      • Iliac crest
    • Composite oromandibular defects: 
      • Fibula
      • Iliac crest
      • Scapula
    • Maxilla +/- orbit defects:
      • Scapula
      • Osteocutaneous radial forearm
      • Fibula
References 
  1. Urken ML. Multidisciplinary Head and Neck Reconstruction: A Defect-Oriented Approach. Wolters Kluwer Health/Lippincott Williams & Wilkins; 2010.
  2. Genden EM. Reconstruction of the Head and Neck: A Defect-Oriented Approach. Thieme; 2012.
  3. Chanowski EJ, Casper KA, Eisbruch A, Heth JA, Marentette LJ, Prince ME, Moyer JS, Chepeha DB. Restoration of the orbital aesthetic subunit with the thoracodorsal artery system of flaps in patients undergoing radiation therapy. J Neurol Surg B Skull Base. 2013 Oct;74(5):279-85. doi: 10.1055/s-0033-1347366. [EBM Level 4]
  4. Moyer JS, Chepeha DB, Prince ME, Teknos TN. Microvascular reconstruction of the orbital complex. Facial Plast Surg Clin North Am. 2009 May;17(2):225-37. [EBM Level 5]
  5. Dowthwaite SA, Theurer J, Belzile M, Fung K, Franklin J, Nichols A, Yoo J. Comparison of fibular and scapular osseous free flaps for oromandibular reconstruction: a patient-centered approach to flap selection. JAMA Otolaryngol Head Neck Surg. 2013 Mar;139(3):285-92. [EBM Level 4]
  6. Eskander A, Kang SY, Teknos TN, Old MO. Advances in midface reconstruction: beyond the reconstructive ladder. Curr Opin Otolaryngol Head Neck Surg. 2017 Oct;25(5):422-430. [EBM Level 5]

Pharmacology

Learning Objectives 
  1. Determine the role of antithrombotic therapy in free tissue transplantation
    • Routine prophylaxis has no demonstrated benefit, but may be utilized as per surgeon preference
    • Use of various agents is common in cases of flap compromise
      • Aspirin
      • Heparin
      • Medicinal leeches
References 
  1. Lighthall JG, Cain R, Ghanem TA, Wax MK. Effect of postoperative aspirin on outcomes in microvascular free tissue transfer surgery. Otolaryngol Head Neck Surg. 2013 Jan;148(1):40-6. (EBM Level 4]
  2. Reiter M, Kapsreiter M, Betz CS, Harréus U. Perioperative management of antithrombotic medication in head and neck reconstruction-a retrospective analysis of 137 patients. Am J Otolaryngol. 2012 Nov-Dec;33(6):693-6. [EBM Level 4]
  3. Chepeha DB, Nussenbaum B, Bradford CR, Teknos TN. Leech therapy for patients with surgically unsalvageable venous obstruction after revascularized free tissue transfer. Arch Otolaryngol Head Neck Surg. 2002 Aug;128(8):960-5. [EBM Level 4]

Surgical Therapies

Learning Objectives 
  1. Describe the relevant anatomy, including the arterial, venous and potential nerve supply or each of the following osseus/osteocutaneous free flaps:
    • Fibula
    • Subscapular:
      • Scapula, parascapular, thoracodorsal scapular tip, serratus rib
    • Iliac crest
    • Radial forearm
  2. Compare and contrast the above flaps with respect to bone stock, available bone length, mobility of associated soft tissue paddle, pedicle length.
References 
  1. Urken ML, Cheney ML, Blackwell KE, Harris JR, Hadlock TA, Futran N. Regional and Free Flaps for Head and Neck Reconstruction: Flap Harvest and Inseting. 2nd ed. Philadelphia: Wolters Kluwer, Lippincott Williams & Wilkins; 2012.

Rehabilitation

Learning Objectives 
  1. Anticipate and diagnose pertinent rehabilitative issues in patients undergoing bony flap reconstruction
    • Operative morbidity at the head and neck reconstructive site
      • Poor articulation
        • Loss of mandibular/maxillary height
        • Scarring of native tongue to transplant
      • Dysphagia
        • Oral incompetence
        • Poor oral phase of swallow
        • Velopharyngeal insufficiency
        • Aspiration as possible consequence of above
      • Pain
    • Donor site morbidity
      • Ambulation rehabilitation for fibula and iliac crest donor sites
      • Shoulder rehabilitation for scapular and latissimus donor sites
      • Ambulation and postoperative pulmonary toilet for iliac crest donor site
      • Fracture, tendon exposure, loss of grip strength, cold intolerance for forearm donor site
      • Pain
    • Rehabilitative services
      • Speech pathology
      • Swallow therapy
      • Physical therapy
      • Occupational therapy
      • Oral surgery and prosthedontics
  2. Anesthesia/pain services

Case Studies

  1. 57-year-old man with T4N2bM0 SCCA of right lateral mandible with involvement of adjacent floor of mouth and overlying facial skin.
    • Ablation will create complex defects in all parts of the oral cavity with need for oral lining, bone replacement, and external facial coverage.
    • Options include scapular bone flap with two skin paddles, iliac crest with skin paddle and internal oblique muscle, fibula flap with skin island and flexor hallucis longus muscle or combination of two free flaps.
  2. 38-year-old woman with T4 lacrimal gland high-grade adenocarcinoma. Concerned about her cosmetic outcome in addition to her oncologic outlook.
    • Ablation involves orbital extenteration, loss of eyelids and superior and lateral orbit bone.
    • Options include
      • Osteocutaneous radial forearm flap as likely first choice.
        • Bone reconstructs lateral and superior orbit for contour and skin paddle can be designed to fill the orbit.
      • If resection involves more facial skin, or additional bone reconstruction required (such as in concurrent maxillectomy), sub-scapular system flap (classic scapula or thoracodorsal artery scapula tip) is an excellent option.
References 
  1. Chanowski EJ, Casper KA, Eisbruch A, Heth JA, Marentette LJ, Prince ME, Moyer JS, Chepeha DB. Restoration of the orbital aesthetic subunit with the thoracodorsal artery system of flaps in patients undergoing radiation therapy. J Neurol Surg B Skull Base. 2013 Oct;74(5):279-85. [EBM Level 4]
  2. Chepeha DB, Khariwala SS, Chanowski EJ, Zumsteg JW, Malloy KM, Moyer JS, Prince ME, Sacco AG, Lee JS. Thoracodorsal artery scapular tip autogenous transplant: vascularized bone with a long pedicle and flexible soft tissue. Arch Otolaryngol Head Neck Surg. 2010 Oct;136(10):958-64. [EBM Level 4]

Complications

Learning Objectives 
  1. Recognize flap compromise and intervene for salvage
  2. Manage wound complications at both the transplant and donor site
    • Flap vascular compromise
      • Arterial insufficiency from spasm or clot
        • Cool, pale skin paddle with slow or no capillary refill
        • No blood on pinprick
      • Venous compression or thrombosis
        • Blue or purple skin paddle; tense, turgid flap with flash capillary refill
        • Fast, dark blood on pinprick
      • Both situations mandate return to the OR 
    • Defect site
      • Hematoma/seroma
      • Fistula
      • Partial flap loss
      • Complete flap loss
    • Flap monitoring techniques
      • Direct tissue observation, including pinprick
      • External tissue monitoring island for buried flaps
      • Doppler signal over pedicle and/or perforator
      • Implanted Doppler probes on pedicle
    • Donor site
      • Hematoma/seroma
      • Wound dehiscence
      • Tendon exposure – radial forearm
      • Neuropraxia – radial forearm, fibula
      • Abdominal hernia - iliac crest
      • Compartment syndrome –fibula
References 
  1. Urken ML, Cheney ML, Blackwell KE, Harris JR, Hadlock TA, Futran N. Regional and Free Flaps for Head and Neck Reconstruction: Flap Harvest and Inseting. 2nd ed. Philadelphia: Wolters Kluwer, Lippincott Williams & Wilkins; 2012.
  2. Urken ML. Multidisciplinary Head and Neck Reconstruction: A Defect-Oriented Approach. Philadelphia: Wolters Kluwer, Lippincott Williams & Wilkins; 2009.
  3. Neligan PC and Wei FC. Microsurgical Reconstruction of the Head and Neck. New York: Thieme; 2009. 
  4. Genden EM. Reconstruction of the Head and Neck: A Defect-Oriented Approach. New York: Thieme; 2012.

 

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