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Indian J Plast Surg 2007 Vol 40 SupplementS3

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Recent advances and controversies in head and neck reconstructive surgery

Moni Abraham Kuriakose, Mohit Sharma, Subramania IyerHead and Neck Institute / Division of Reconstructive Surgery, Amrita Institute of medical Sciences, Kochi - 682026, India

Address for correspondence: Dr. Moni Abraham Kuriakose, Professor and Chairman, Head and Neck Institute, Amrita Institute of Medical Sciences, Kochi - 682 026, India. E-mail: [email protected]

ABSTRACT

Advances in head and neck reconstruction has made signiÞ cant improvement in the quality of life and resectability of head and neck cancer. ReÞ nements in microsurgical free tissue transfer leave made restoration of form and complex functions of head and region a reality. Standardized reconstructive algorithms for common head and neck defects have been developed with predictable results. Some of the major advances in the Þ eld include- sensate free tissue transfer, osseo integrated implant and dental rehabilitation, motorized tissue transfer and vascularized growth center transfer for pediatric mandible reconstruction. However there exist several controversies in head and neck reconstructive surgery. Some are old; resolved partially in the light of recent clinical evidences and others are new, developed as a result of newly introduced reconstructive techniques. These include, primary versus secondary reconstruction, pedicled versus free ß aps, primary closure versus free tissue transfer for partial glossectomy defects, reconstruction of posterior mandible and reconstruction of orbital exenteration defects. Rapid advances in the Þ eld of tissue engineering and stem cell research is expected to make radical change in the Þ eld of reconstructive surgery. This manuscript review progress in head and neck reconstructive surgery during the last decade, current controversies and outline a road map for the future.

KEY WORDS

Free tissue transfer, head and neck, reconstruction, tissue engineering

Free full text on www.ijps.org

INTRODUCTION

Head and neck cancer is one of the leading causes of cancer-related death and disfigurement, particularly in the Indian subcontinent. Although

there has been quite significant progress in the management of head and neck cancer such as the introduction of organ-sparing strategies using concurrent chemo-radiotherapy and biological modulation of cancer with epidermal growth factor pathway interruption, none of the strategies has come close to the contribution made by reconstructive surgery.[1] It has made a profound impact not only in improving the quality of life of patients but also in improving the resectability of advanced head and neck cancers. To a large extent current reconstructive techniques can offer predictable results to restore form

and function and are fast approaching the ultimate reconstructive goal of ̀ replacing like with like’. However, there exist several controversies and limitations.

ALGORITHM-BASED SELECTION OF DONOR SITES FOR HEAD AND NECK RECONSTRUCTION

Reports of studies based on large series during the past decade have helped to establish a general consensus on the choice of reconstructive options and the development of an algorithm-based practice of head and neck reconstructive surgery.[2] The following description outlines the head and neck reconstructive algorithm practised by the authors’ team at the Amrita Institute of Medical Sciences. For the purpose of discussion, the

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common head and neck defects can be categorized as 1. Mid-face, 2. Tongue and floor of mouth, 3. Mandible and 4. Laryngo-pharynx.

MID-FACE RECONSTRUCTION

To assist in the planning and execution of the mid-face region, the defects are classified into four classes and three subgroups as described by Brown [3] in this issue. The priority for reconstruction and the technique are different in each of these groups, which are summarized in Table 1.

Class 1: maxillary alveolectomy defect without maxillary sinus involvementClass 2: maxillectomy defect involving sinus with intact orbital floorClass 3: maxillectomy defect including the orbital floor, but the orbital contents are preservedClass 4: maxillectomy with orbital exenteration Subgroup-a: defect does not cross midlineSubgroup-b: defect crosses midlineSubgroup-c: bilateral defects

An additional Class 5 needs to be incorporated into this classification to describe defects extending to the cranial cavity.

TONGUE AND FLOOR OF MOUTH

The algorithm in tongue reconstruction is shown in Figure 1. A partial glossectomy defect involving less than one-third of the tongue, especially when not involving the tip of the

tongue can be repaired by direct closure or left to heal by secondary intention, especially when the ablation is carried out using laser. Hemi or subtotal glossectomy defect needs reconstruction, which is best carried out using free tissue transfer.[4,5] The choice of flap depends on the reconstructive need. If the defect is restricted to the tongue, without involvement of the floor of the mouth a lateral arm flap suits best. However, if the floor of the mouth is involved, a pliable radial forearm free flap is the better choice of flap. In larger defects differentially thinned antero-lateral thigh flap can also be considered. There is no general consensus on the choice of flap in total glossectomy defect. A total glossectomy with laryngectomy defect can be reconstructed with pedicled pectoralis major myocutaneous flap. Choice of flap in total glossectomy defect with preserved larynx is controversial and is discussed later.

MANDIBLE RECONSTRUCTION

The algorithm in the management of mandibular defect is now well defined and is outlined in Figure 2. The reconstructive needs and choice of flap depends on the site of defect and the dentate status of the patient.[6]

A lateral defect distal to the premolar teeth, especially in edentulous patients can be reconstructed using pedicled flaps. However, lateral defects in dentate patients and anterior mandibular defects require skeletal reconstruction. The choice of flap depends on the site of the defect and the associated soft tissue requirements. Table 2 summarizes the choice of flaps in this scenario.

LARYNGO-PHARYNX RECONSTRUCTION

Primary closure, if it can be obtained, is the ideal

Table 1: Classifi cation of mid-face defects and reconstructive options

Class Sub Order of reconstructive Reconstructive group priority options1 a-c Dental rehabilitation Obturator2 a Dental rehabilitation Obturator DCIA ß ap2 b-c Nasal support Fibula osseo-cutaneous Dental rehabilitation ß ap or DCIA ß ap3 a Orbital support Fibula osseo-cutaneous Dental rehabilitation ß ap3 b-c Orbital support Fibula osseo-cutaneous Nasal support ß ap Dental rehabilitation4 a-c Base for orbital Rectus free ß ap prosthesis reconstruction Orbital prosthesis5 a-c Separation of cranial Rectus free ß ap and oral cavity reconstructionDCIA: Deep circumß ex ileac artery Figure 1: Algorithm in tongue reconstruction

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Head and neck reconstruction

reconstruction of pharyngectomy defects. This permits restoration of pharyngeal conduit and better voice rehabilitation with tracheo-oesophageal voice prosthesis. This is however not possible or desirable in certain scenarios. This includes salvage laryngo-pharyngectomy following chemo-radiotherapy and extended and total pharyngectomy. Choice of flaps in pharyngectomy defects is discussed in detail elsewhere in this issue, which is summarized in Table 3.

CONTROVERSIES IN HEAD AND NECK RECONSTRUCTION

There exist several controversies in head and neck reconstructive surgery. Some are old, resolved partially in the light of recent clinical evidences and others are new, developed as a result of newly introduced reconstructive techniques. These are discussed below:1. Primary versus secondary reconstruction2. Pedicled versus free flaps3. Primary closure versus free tissue transfer for partial

glossectomy defects4. Reconstruction of posterior mandible 5. Reconstruction of orbital exenteration defect

Primary versus secondary reconstruction in head and neck cancer surgeryThe argument for secondary reconstruction was primarily centred on the concern that reconstructed tissue can delay detection of recurrence. In addition, during the era of pedicled flaps and multi-stage reconstruction, there was concern of delay in implementing the essential postoperative radiotherapy required for optimal control of the disease. Previously the multi-stage reconstruction often extended beyond the optimal period of initiation of adjuvant radiotherapy which is six weeks after completion of surgery.

With the availability of reliable, single-stage reconstructive procedures and the often-practiced two-team approach, head and neck reconstruction can be performed expeditiously and with predictable outcome. Improved quality of life with primary reconstruction is now considered an overriding argument for primary reconstruction. Availability of high-definition anatomic and metabolic imaging studies also facilitates detection of local recurrence and counters the argument to delay reconstruction.

Secondary reconstruction has almost become obsolete with a few exceptions. In circumstances when there is lack of microvascular surgical expertise or due to inherent patient factors, it may still be necessary to employ alternative methods of reconstruction and/or delay definitive reconstruction.

Pedicled versus free fl aps in head and neck reconstructionIn reconstruction of head and neck defects after cancer resections, the traditional concept of the `reconstructive ladder’ has now been replaced with the concept of ‘reconstructive elevator’ or ‘reconstructive escalator’. In this concept, there is no need to strictly follow the

Table 3: Choice of fl ap in laryngo-pharyngeal defects

Extent of defect Reconstructive optionPartial pharyngectomy with Primary closureretained mucosa of 3 cm or more Retained pharyngeal mucosa of Pectoralis major ß ap with skinless than 3 cm width or in most paddlecases of salvage laryngectomy after chemo-radiotherapy Circumferential pharyngeal Jejunum or anterolateral thighdefect, inferior extent above free ß apthe manubriumCircumferential pharyngeal Gastric transpositiondefect, inferior extent below the manubrium

Figure 2: Algorithm in mandibular reconstruction

Mandibular Defects

Table 2: Choice of fl ap for mandibular reconstruction

Choice of fl apReconstructive Site of defectneed Anterior Lateral CombinedBone++Soft tissue -/+ Fibula DCIA FibulaBone++Soft tissue -/+ Fibula DCIA FibulaBone++Soft tissue -/+ Radial forearm Rectus pect Fibula + pect Þ bula + Radial major major forearm DCIA: Deep circumß ex ileac artery


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reconstructive ladder of considering the simpler procedures first and then escalating to complex procedures; but rather to choose the most appropriate technique as the initial procedure. Choice of reconstructive options depends on various factors such as site of the defect, type of tissue required, functional and cosmetic implications of the defect, associated co-morbidity and availability of resources. In most head and neck defects there is often an ‘ideal reconstruction’ option. This however needs to be selected based on the factors related to the anatomical and functional defect and also based on the patient factors and available expertise.

The concept of primary reconstruction of head and neck cancer surgery defects began with the advent of delto-pectoral, forehead and pectoralis major myocutaneous flaps. For years, pectoralis major myocutaneous flap has been the workhorse for reconstruction of a variety of defects in the head and neck region. Latissimus dorsi, trapezius, platysma myocutaneous flaps are the other less utilized pedicled flaps. However, all these flaps have limitations. Firstly, they have a limited reach because of which there are more chances of distal flap failure and wound gape due to tension by the downward pull of the flaps. Secondly, the type of tissue in the flap, its bulk and pliability does not always suit the defect to be reconstructed. Thirdly, it may not be possible to contour the flap to the defect in different planes than that of the pedicled flap.

All these drawbacks can be overcome by the use of free tissue transfer. Though the reliability and utility of free tissue transfer is established in head and neck reconstruction, the technique is not frequently adopted because of various reasons. Surgical expertise, the time factor and questionable benefit in advanced cases with poor prognosis were some of the arguments against the wide use of free tissue transfer. But today, with widespread practice of the technique, availability of structured training in microvascular surgery, safe anaesthesia and two-team approach these factors can readily be overcome in many tertiary care centres. Free flaps are also associated with some drawbacks like the need for vigorous monitoring and re-exploration if required. Donor site morbidity limits its use in patients with co-morbidity. Extremes of age of the patient, however, are found not to be a contraindication for free tissue transfer.

Certain locations in the head and neck region cannot be effectively reconstructed without free tissue transfer. These include anterior and antero-lateral mandibular defects and

major skull base defects. The cost-effectiveness of free flaps has also been reported as no worse than the pedicled flaps. However, for certain defects such as patch defects of the pharynx and posterior mandibular defect, pectoralis major myocutaneous flap is the preferred reconstructive option because of its reliability and ease of technique. For the reconstruction of smaller cutaneous defects, local flaps are better because of better colour and texture match.

So, today the surgeon has a variety of reconstructive options to choose from. Hence, the choice should be based on the nature of the defect, its functional implications, patient factors and availability of resources.

Primary closure versus free tissue transfer for partial glossectomy defectsThe main functions of tongue are speech and swallowing. In speech, tongue is involved in the articulation of the consonants and hence the intelligibility of speech. Tongue mobility is a key factor affecting speech intelligibility.[7] Tongue is also involved in mixing the food and chewing and pushing the food backward for swallowing. So, the aims of the reconstructive surgery should be to restore these functions. As the tissue we use for reconstruction is adynamic, functional reconstruction of such a vital and dynamic structure at present is an elusive goal. However, the reconstructive technique should attempt to take advantage of the mobility of the residual tongue as well as that of the floor of mouth, in addition to restoring the volume of the tissue lost. The most appropriate reconstructive choice depends on the size of the tongue resection and site of the defect. As more tongue is lost, normal function is less likely to be restored; and a bulkier flap is required to reconstruct the defect adequately. Defects involving the floor of mouth or tip of tongue require a thin and pliable flap. Partial glossectomy defects following resections for cancer of the anterior two-thirds of the tongue vary in size and site. These defects may extend to the floor of the mouth and partly to the base of the tongue. Defects, which are less than one-third of the oral tongue, medio-laterally and antero-posteriorly, if closed primarily or left to heal by secondary intention produce no major limitation of tongue movement or loss of significant bulk. Hence, speech and swallowing are not significantly affected.

Those defects that exceed more than two-thirds of tongue require flap reconstruction for optimal result.

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This is particularly true if the defect extends to the floor of mouth.

The issue of reconstruction is controversial in partial glossectomy defects that are between one-third and two-thirds of the tongue. Many surgeons adopt primary closure of these defects with good functional results.[8] Some studies show better results with reconstruction.[5] However, the small number of patients in these studies and the fact that all types of flaps have been included in the reconstruction do not make the results reliable. Pedicled flaps that have been utilized include nasolabial, platysma, submental or pectoralis major flaps whereas the free flaps reported to be useful include lateral arm and radial forearm flaps and of late anterolateral thigh flaps.

However, studies that compare functional results between these methods are limited. Studies with small numbers have compared results between pectoralis major and radial forearm flap and the results are reported to be better with the latter.[9,10]

Reconstruction of posterior mandibleOptions for posterior mandibular reconstruction, distal to the molar teeth segment, are no reconstruction, soft-tissue reconstruction and osseous reconstruction. Proponents for no reconstruction or reconstruction with soft-tissue flap argue that in dentate patients the teeth will guide the mandible into normal alignment and there will not be any significant functional deficit. In edentulous patients, deviation of jaw is not a concern as there is no occlusion to be maintained. Argument for osseous reconstruction is that, it maintains symmetry of mandible at rest and on opening the mouth. Moreover, over time, unopposed action of the contralateral mandible can cause significant deviation of the mandible. This is important in dentate patients where occlusal relationship is essential for optimal functional outcome. Our policy is to offer osseous reconstruction in all patients other than elderly patients with edentulous mandible and those who have preexisting restriction of mouth opening as in submucous fibrosis.

Reconstruction of orbital exenteration defectControversy regarding the reconstruction of orbital exenteration defect is whether to excise the eyelids and obliterate the cavity and offer an orbital prosthesis or to maintain the eyelids and orbital cavity and offer an

ocular prosthesis. The advantage of the former is that the result is more predictable, although the aesthetic result of orbital prosthesis is far inferior to ocular prosthesis. The advantage of the latter is better aesthetic result, however with several potential problems. For an ocular prosthesis, it is essential to have an orbital floor and a cavity lined with skin. In addition the function of the orbicularis occuli and levator muscles should be maintained. The latter reconstruction although more challenging and less predictable, offers a better aesthetic result than provided by an orbital prosthesis.

RECENT ADVANCES IN HEAD AND NECK RECONSTRUCTION

There were several notable advances in head and neck reconstruction in the recent past. Some of the developments, which have changed clinical practice or will do so in the near future, are outlined below:1. Sensate free tissue transfer2. Osseo integrated implant and dental rehabilitation3. Motorized tissue transfer4. Vascularized growth centre transfer for paediatric

mandible reconstruction

Sensate free tissue transferOral mucosal sensory feedback plays a critical role in many stomatognathic functions such as mastication, oral hygiene, phonation and swallowing and can influence the patient’s quality of life. This goal of sensory feedback can be achieved by use of sensate free tissue reconstruction. It requires transfer of a composite functional unit with its own vascular supply (angiosome)[11] and innervated by a sensory nerve (neurosome).[12] Taylor et al.,[13] in detailed cadaveric studies, demonstrated various neurovascular territories of the body. They made the observation that cutaneous nerves often run along with blood vessels in an overlapping distribution of angiosomes and neurosomes. This work suggests that many of the currently used axial or fasciocutaneous flaps can be potentially modified as neurovascular flaps. Several authors have reported successful sensate free flap transfer of oral cavity defects with successful restoration of sensation.

Radial forearm free flap with lateral antebrachial cutaneous nerve is the commonly used sensate flap in the head and neck region.[14-16] What is not convincingly reported as yet, is either improvement in function or quality of life of patients with sensate flap reconstruction.


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Vascularized growth centre transfer in paediatric mandibleMandibular reconstruction in a growing child is a challenging problem, requiring transfer of bone with growth potential to avoid progressive facial deformity. Today there are various options available to us for addressing this complex issue.[17]

Epiphysis and hemi-joint transfer for reconstruction of the temporomandibular joint and ramus-condyle unit, using the proximal epiphyseal plate and proximal one-third of the diaphyseal shaft of the fibula has been successfully performed in cases of hemifacial microsomia.[18] Pruzansky Type II and III patients have reported to have a good range of painless movement at the temporomandibular joint and growth at the neo ramus-condyle unit.

Microvascular temporomandibular joint (TMJ) and mandibular ramus reconstruction can be performed in patients with absence of the vertical mandibular ramus using metatarsophalangeal (MTP) joint transplantation. This technique appears to be a promising alternative in the treatment of children with Pruzansky Type III hemifacial microsomia. Various teams have used costochondral grafts for reconstruction of the mandibular condyle and ramus.[19] The latter technique has gained increasing popularity in the reconstruction of the temporomandibular joint and condyle in patients with hemifacial microsomia and temporomandibular joint ankylosis during the growth period. Long-term follow-up has shown some patients have excessive growth of the graft, while others have suboptimal or no growth pointing to the fact that the growth pattern of the costochondral graft is unpredictable.[20]

For oncological reconstruction, the defect will include both bone as well as associated soft tissue. In addition, the majority of these patients have to undergo postoperative radiotherapy. This precludes the use of free costochondral graft. An alternative technique would be the use of vascularied rib along with serratus anterior muscle based on the thoracodoral vascular pedicle.[21] This has the potential advantage of vascularised growth centre transfer and soft tissue for reconstruction [Figures 3 a-d].

Dynamic muscle transferIn head and neck reconstruction functional muscle transfer is an established concept for facial reanimation surgery. This concept is increasingly being used for oncological reconstruction, particularly in reconstruction of major

glossectomy defects.

The priorities to be considered while reconstructing total or near total glossectomy patients are airway protection, swallowing and articulation. The transfer of static tissue acts mainly by providing bulk for glosso-palatal contact. It also helps in swallowing and speech to some extent.[22]

The use of dynamic muscle transfer for total tongue reconstruction can actively suspend the larynx and allows for better speech and swallowing by providing coordinated tongue movements.[23,24]

This reconstructive technique has recently been refined by us using innervated gracilis along with a gastro omental flap. The logic behind choosing this combination is that the innervated gracilis muscle provides active tongue movements for coordinated swallowing and better speech and allows elevation of the larynx during swallowing which helps in preventing aspiration. The gracilis muscle closely matches the normal tongue in its cross-sectional diameter. The muscle can be trimmed to a requisite length and can be accommodated easily in the limited space provided within the mandibular arch.

It is well documented that the gastric mucosa has good radiation tolerance capacity.[25] That the stomach mucosa has inherent secretory capability in response to local stimuli is another important factor in decision-making for the use of the gastro omental flap. The stomach is used in an inside-out fashion, so that it can act as an alternative source of secretion. As virtually all patients undergoing subtotal glossectomy require adjuvant postoperative radiotherapy and have the risk of developing xerostomia, the secretion from the gastric lining is an added advantage. The omentum is sandwiched between the stomach and floor of mouth to provide the bulk needed for adequate glosso palatal contact. Moreover, with the use of this combination of tissues, the colour and appearance of the neo tongue very closely match the original tongue [Figures 4a, b].

Osseointegrated implants and dental rehabilitationThe primary function of jawbones is to provide support for teeth. Therefore reconstruction of the jawbone will not be complete without appropriate dental rehabilitation. Dental restoration with the assistance of a prosthodontist is essential for total functional reconstruction. Dental rehabilitation can be carried out either using removable prosthesis or fixed prosthesis. The surgical bed should be optimized for dental restoration. This includes:

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Figure 3c: Composite free latiismus dorsi- serratus anterior with rib incorporating costal cartilage

Figure 3d: Same child 2 years post-operatively showing symmetrical growth of the face


! Availability of occlusal space of 10 to 15 mm ! Aligning the neo-mandible to the opposing natural

teeth

! Neo-mandible lined with mucosa rather than skin, which is firmly attached to the underlying bone

! Providing adequate bone and soft-tissue support for

Figure 4b: Reconstructed tongue maintaining its volume and lubricated surface six months after radiation therapy

Figure 4a: Graphic representation of combined gastroomental and dynamic gracilis ß aps for total tongue reconstruction

Gastric mucosa

Omentum

Tongue remnantGracilis

Figure 3a: Child with recurrence of Þ brous histiocytoma affecting the mandible and infratemporal fossa

Figure 3b: CT scan of the same child


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the teeth bordering the defect

Currently available reconstructive techniques need to be modified to meet these requirements. The bone flap should be aligned to the lower border of the mandible. Care should be taken to provide optimal inter-alveolar space (10 to 15 mm), particularly at the molar teeth segment. A ̀ bite-block’ can be prepared preoperatively, to ensure occlusal space, as well as alignment with opposing teeth. Skin is a poor substitute for mucosa. Moreover, the skin over the osteo-cutaenous flaps is mobile affecting stability of the denture. This can be avoided by de epithelization of skin paddle or avoiding skin paddle altogether and have muscle or fascia as oral lining. Lack of skin facilitates contracture of the oral lining on to the bone and permits mucosilization of the flap. Care should be taken to maintain adequate bone and soft-tissue support at the time of primary mandibulectomy.

In a large number of patients conventional denture cannot be fabricated because of the morphology of the neo-mandible and lack of support from adjacent natural dentition. Dental restoration in these patients can be undertaken using osteointegrated implants.[26] This is a two-stage procedure in which titanium implants of appropriate dimension are inserted into the bone and allowed to integrate with the bone which takes about three months. After that period, the implant needs to be exposed and an abutment is attached to the implant. A fixed prosthesis can be fabricated on these abutments. The number and position of abutments needs to be carefully planned with the prosthodontist.

These implants can be placed either at the time of primary surgery or as a secondary procedure.[27] The proponents of primary implantation argue that it avoids additional surgery, expedites the rehabilitation of the patients and more importantly allows predictable osteointegration as the implants are placed prior to start of radiotherapy, which is required in most of these patients. The implant placement also is technically easier as there is wide exposure of oral cavity during the primary surgical procedure. The main disadvantage of the primary implantation is that in the event of flap failure, albeit low, there will be failure of implants too. In addition implant placement also increases the operating time of an already lengthy procedure.

The advantage of secondary placement of the implants is that the implant placement can be performed as an office procedure, after ensuring success of bone flap. Moreover,

the implants can be placed with accurate alignment with the opposing teeth using template. The main disadvantage of secondary implant placement is that the implant is inserted in an already irradiated bone with about 20% lower integration rate.[27]

Our practice is to perform implantation for those patients who undergo resection for benign diseases as primary procedure and as a secondary procedure in malignant diseases.

Future developments in head and neck recon-structionExciting developments in tissue engineering hold promise for the future, either as an `off the shelf ’ reconstruction option or by incorporating the technique into the conventional techniques to improve their efficiency or lower the donor site morbidity. This technology is likely to change the way we reconstruct tissue defects in the future.[28] Although tissue engineering is considered as experimental at present, based on Phase III clinical trials two products are currently available for clinical use. These are recombinant Bone Morphogenic Protein (rhBMP-2) for spine fusion (INFUSE, Medtronic Sofamor Danek, Memphis, Tennessee) and a cell-based therapy of autologous chondrocyte implantation for articular disc replacement (Carticel, Genzyme Biosurgery, Cambridge, MA).

Tissue engineering involves regeneration of new tissue through the use of biological mediators or scaffold. Success of tissue engineering depends on the effective participation of three components-scaffold, signalling molecules and cells. Either all or some of these components are introduced for the regeneration of tissue. The scaffolds used at present are either natural tissue such as collagen, acellular dermis or demineralized bone matrix; polymers such as polyglycolic acid or metal (Titanium). The scaffold should have mechanical properties to provide tissue morphology and have chemical properties to serve as bio-molecule carriers. Signalling molecules to be incorporated into the system will provide signalling to activate tissue regeneration. This can be either in the form of biologically active molecules (e.g., rhBMP), gene therapy to deliver genes coding for the biologically active molecule or as tissue-specific cells (e.g., chondrocyte, keratinocyte).

Tissue engineering has progressed farthest in bone regeneration. RhBMP-2 and rh-BMP-7 are in use for spine fusion and for long bone non-unions. In the head and neck

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region this is being used in alveolar regeneration and in sinus floor augmentation procedures.[29] This concept was recently applied for regeneration of a 6cm segmental bony defect of the mandible.[30,31] Bone marrow stromal cells loaded in a demineralized bone matrix scaffold have been successfully used for calvarial bone defects.

Autologous chondrocyte cultured ex vivo and loaded in polyglycolic acid scaffold has been used for regeneration of cartilage. This has been successfully used for auricular cartilage reconstruction in animals.[32]

Another area where tissue engineering is showing promise is in tracheal regeneration. Animal studies where composite chondrocyte was delivered in polyglycolic acid scaffold and later seeded with epithelial cells have shown to regenerate composite cartilage-transitional cell epithelial sub-unit of trachea.[33]

CONCLUSION

Rapid progress in head and neck reconstructive surgery has helped in developing reliable and effective strategies to restore form and function. The advent of tissue engineering is showing promise for the future to lower donor site morbidity and improve the aesthetic and functional result.

REFERENCES

1. Harari PM. Promising new advances in head and neck radiotherapy. Ann Oncol 2005;16:vi13-9.

2. Hurvitz KA. Kobayashi M. Evans GR. Current options in head and neck reconstruction. Plast Reconstruct Surg 2006;118:122e-33e.

3. Brown JS, Rogers SN, McNally DN, Boyle M. A modiÞ ed classiÞ cation for the maxillectomy defect. Head Neck 2000;22:17-26.

4. Haughey BH, Taylor M, Fuller D. Facio cutaneaous flap reconstruction of tongue and ß oor of mouth. Arch Otolarygol Head Neck Surg 2002;128:1388-95.

5. Hsiao HT, Leu YS, Kin CC. Primary closure versus radial forearm ß ap reconstruction after hemiglossectomy: Functional assessment of swallowing and speech. Ann Plast Surg 2002;49:612-6.

6. Mehta RP, Deschler DG. Mandibular reconstruction in 2004: An analysis of different techniques. Curr Opin Otolaryngol Head Neck Surg 2004;12:288-93.

7. Bressmann T, Sader R, Whitehill TL, Samman N. Consonant intelligibility and tongue motility in patients with partial glossectomy. J Oral Maxillofac Surg 2004;62:298-303.

8. Chuanjun C, Zhiyuan Z, Shaopu G, Xinquan J, Zhihong Z. Speech after partial glossectomy: A comparison between reconstruction and nonreconstruction patients. J Oral Maxillofac Surg 2002;60:404-7.

9. Su WF, Hsia YJ, Chang YC, Chen SG, Sheng H. Functional comparison after reconstruction with a radial forearm free ß ap or a pectoralis major ß ap for cancer of the tongue. Otolaryngol Head Neck Surg 2003;128:412-8.

10. Su WF, Chen SG, Shang H. Speech and Swallowing function after reconstruction with a radial forearm free ß ap or a pectoralis major ß ap for tongue cancer. J Formos Med Assoc 2002;101:472-7.

11. Taylor GI, Palmer JH. Vascular territories (angiosomes) of the body: Experimental study and clinical applications. Br J Plast Surg 1987;40:113-41.

12. Rhee JS, Weisz DJ, Hirigoyen MB, Sinha U, Alcaraz N, Urken ML. Intraoperative mapping of sensate ß aps: Electrophysiologic techniques and neurosomal boundaries. Arch Otolaryngol Head Neck Surg 1997;123:823-9.

13. Taylor GI, Gianoustsos MP, Morris SF. The neurovascular territories of the skin and muscles: anatomic study and clinical implications. Plast Reconstr Surg 1994;94:1-36.

14. Urken ML, Weinberg H, Vickery C, Biller HF. The neurofascio cutaneaous radial forearm ß aps in head and neck reconstruction: A preliminary report. Laryngoscope 1990;100:161-73.

15. Boyd B, Mulholland S, Gullane P, Irish J, Kelly L, Rotstein L, et al. Reinnervated lateral antebrachial cutaneous neurosome ß ap in oral reconstruction: Are we making sense? Plast Reconstr Surg 1994;93:1350-62.

16. Kuriakose MA, Loree TR, Spies A, Meyers S, Hiks WL Jr. Sensate radial forearm free ß aps in tongue reconstruction. Arch Otolaryngol Head Neck Surg 2001;127:1463-6.

17. Phillips JH, Rechner B, Tompson BD. Mandibular growth following reconstruction using a free Þ bula graft in the pediatric facial skeleton. Plast Reconstr Surg 2005;116:419-26.

18. Vilkki SK, Hukki J, Nietosvaara Y, Hurmerinta K, Suominen E. Microvascular temporomandibular joint and mandibular ramus reconstruction in hemifacial microsomia. J Craniofac Surg 2002;13:809-15.

19. Ko EW, Huang CS, Chen YR. Temporomandibular joint reconstruction in children using costochondral grafts. J Oral Maxillofac Surg 1999;57:789-800.

20. Guyuron B, Lasa CI Jr. Unpredictable growth pattern of costochondral graft. Plast Reconstr Surg 1992;90:880-9.

21. Richards MA, Poole MD, Godfrey AM. The serratus anterior/rib composite ß ap in mandibular reconstruction. Br J Plast Surg 1985;38:466-77.

22. Lyos AT, Evans GR, Perez D, Schusterman MA. Tongue reconstruction: outcomes with the rectus abdominis ß ap. Plast Reconstr Surg 1999;103:442-7,48-9.

23. Yousif NJ, Dzwierzynski WW, Sanger JR, Matloub HS, Campbell BH. The innervated gracilis musculocutaneous ß ap for total tongue reconstruction. Plast Reconstr Surg 1999;104:916-21.

24. Yoleri L, Mavioglu H. Total tongue reconstruction with free functional gracilis muscle transplantation: A technical note and review of the literature. Ann Plast Surg 2000;45:181-6.

25. Devineni VR, Hayden R, Fredrickson J, Sicard G. Tolerance of gastric mucosal ß ap to postoperative irradiation. Laryngoscope 1991;101:462-4.

26. Gurlek A, Miller MJ, Jacob RF, Lively JA, Schusterman MA. Functional results of dental restoration with osseointegrated implants after mandible reconstruction. Plast Reconstr Surg 1998;101:650-9.

27. Chang YM, Santamaria E, Wei FC, Chen HC, Chan CP, Shen YF, et al. Primary insertion of osseointegrated dental implants into Þ bula osteoseptocutaneaous free ß ap for mandible reconstruction. Plast Reconstr Surg 1998;102:680-8.

28. Nussenbaum B, Tecnos TN, Chepeha DB. Tissue engineering: Current status of this futuristic modality in head and neck reconstruction. Curr Opin Otolaryngol Head Neck Surg 2004;12:311-5.

29. Warnke PH, Coren AJ. First experiences with recombinant human bone morphogenetic protein 7 (osteogenic protein 1) in a human



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case in maxillofacial surgery. Plast Reconstr Surg 2003;111:2471-2.

30. Moghadam HG, Urist MR, Sandor GK, Clokie CM. Successful mandibular reconstruction using a BMP bioimplant. J Craniofac Surg 2001;12:119-28.

31. Chai G, Zhang Y, Liu W, Cui L, Cao YL. Clinical application of tissue engineered bone repair of human craniomaxillofacial bone defects. Zhonghua Yi Xue Za Zhi 2003;83:1676-81.

32. Shieh SJ, Terada S, Vacanti JP. Tissue engineering auricular

reconstruction: In vitro and in vivo studies. Biomaterials 2004;25:1545-57.

33. Kojima K, Bonassar LJ, Roy AK, Mizuno H, Cortiella J, Vacanti CA. A composite tissue-engineered trachea using sheep nasal chondrocyte and epithelial cells. FASEB J 2003;17:823-8.

Source of Support: Nil, Confl ict of Interest: None declared.

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