Добавил:
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Учебники / Craniomaxillofacial.Reconstructive.and.Corrective.Bone.Surgery.3HAXAP.pdf
Скачиваний:
650
Добавлен:
07.06.2016
Размер:
46.49 Mб
Скачать

36

Marginal Mandibulectomy

Sanford Dubner and Keith S. Heller

Segmental mandibulectomy has traditionally been the mainstay of surgical therapy for oral squamous cell carcinoma adjacent to or invading the mandible and is the “gold standard” against which all other operations must be compared. Its advantages include adequate margins of resection, excellent exposure, and ease of closure, often without the need for soft tissue flaps. However, the functional and cosmetic consequences of this procedure are devastating to the patient.

Because a tumor does not invade the mandible through periosteal lymphatics,1,2 surgeons have gradually changed the way in which they manage intraoral cancers. More conservative procedures have been devised to avoid the cosmetic and functional problems arising from segmental mandibulectomy. Mandibulotomy is used to provide access to oral and oropharyngeal malignancies when there is intervening grossly normal tissue between the tumor and bone. Marginal mandibulectomy can be employed to remove a tumor that involves only periosteum or cortical bone. Both techniques, when used appropriately, provide an adequate margin of resection without significantly disrupting mandibular form or function.

The indications for marginal mandibulectomy vary among authors. Gilbert et al.3 recommended segmental mandibulectomy for alveolar lesions, tumors clinically adherent to the mandible, or for radiographic evidence of bone involvement. Bone involvement did not correlate with tumor location, stage, grade, or extent of metastatic nodal disease. Randall recommended marginal mandibulectomy only when there was no radiographic evidence of bone erosion and less than 50% of the mandibular circumference was involved by tumor.4 Shaha et al.5 used marginal mandibulectomy for the treatment of smaller floor of mouth malignancies and segmental mandibulectomy for larger tumors. This resulted in a 21% recurrence rate at the primary site following marginal mandibulectomy. Barttelbort et al.6 reported a 25% local recurrence rate following marginal mandibulectomy, and a 36% local recurrence rate following segmental mandibulectomy. The local failures all occurred in soft tissue and not in bone.

We reported a 19% local recurrence rate in all patients who underwent marginal mandibulectomy, and a 6% local recurrence rate following segmental mandibulectomy.7 Our series was a retrospective review of 130 consecutive patients who underwent marginal or segmental mandibulectomy for squamous cell carcinoma of the oral cavity or oropharynx. Seventy-nine patients underwent marginal mandibulectomy and 51 segmental mandibulectomy. The distribution of tumors by site is indicated in Table 36.1. Fifteen of the 79 patients who underwent marginal mandibulectomy had local recurrence of disease, which was independent of the size of the tumor. Two thirds of the patients with locally recurrent disease following marginal mandibulectomy were rendered disease free at the primary site with further surgery, for an ultimate local control rate of 94%. These data suggest that even when marginal mandibulectomy is performed in the presence of superficial bone erosion and invasion, the eventual local control rate is no worse than that following segmental mandibulectomy.

Local recurrence is also independent of nodal status. Our series refutes the concept that tumors that are more likely to metastasize are more likely to recur locally. The lack of correlation of recurrence with degree of bone invasion supports the concept proposed by Pogrel that cortical bone involvement is not a contraindication to preserving mandibular continuity.8

Tumor size alone is not a contraindication to marginal mandibulectomy. The local recurrence rate following marginal mandibulectomy in our series is independent of the size of the primary tumor. Other nononcologic factors must be considered when deciding whether marginal mandibulectomy is feasible. Such factors include the patient’s dentition and the mandibular height. A postoperative mandibular strut that is inadequate to support a denture or osseointegrated implants, which is almost certain to fracture with mastication, should dissuade one from proceeding with marginal mandibulectomy. In this situation, segmental mandibulectomy with immediate mandibular reconstruction will undoubtedly better serve the patient in the long run.

411

412

S. Dubner and K.S. Heller

TABLE 36.1 Distribution by tumor site.

 

Type of mandibulectomy

Site

Marginal

Segmental

 

 

 

Floor of mouth

40

10

Gingiva

24

19

Retromolar trigone

8

9

Buccal

4

3

Base of tongue

3

7

Tonsil

0

3

 

 

 

The accurate preoperative assessment of the extent of bone invasion is a difficult problem. An assortment of techniques have been employed, including clinical evaluation, panoramic radiographs, bone scans, computerized tomography (CT), dental scans, and magnetic resonance imaging (MRI). In a study by Shaha,9 clinical evaluation was the most accurate, both to determine bone invasion and to decide the type of mandibular resection necessary. The various radiographic techniques are of little help in making the critical decision of the feasibility of marginal mandibulectomy. This is particularly important because cortical invasion may not preclude marginal mandibulectomy. Certainly if CT or dental scan shows deep invasion, a marginal mandibulectomy should not be performed.

The technique of marginal mandibulectomy has been described and modified in several papers.4,8,10 Sagittal inner table mandibulectomy is ideal for those carcinomas that do not affect the alveolus, but rather the lingual gingiva. This technique preserves the buccal cortex and the buccal edges of the superior and inferior edges of the mandible. The usual marginal mandibulectomy resects the alveolar ridge in conjunction with the lingual cortex, preserving the buccal and inferior cortices. This resection must extend below the mylohyoid line, because preservation of this musculature may result in tumor recurrence within the deep musculature of the floor of the mouth.

FIGURE 36.2 Bilateral nasolabial flap reconstruction of marginal mandibular defect.

Reconstruction of the resulting defect is determined by multiple factors, including the extent of the defect, its location (anterior or lateral), remaining dentition, the need for prosthetic dental rehabilitation, and any history of prior irradiation. Most surgeons agree that the best time to correct any deformity is at the time of the extirpation. Although primary closure of a defect or leaving an open defect and allowing it to granulate and heal secondarily will achieve a stable wound, this often results in a functionally unacceptable postoperative closure. The tongue will frequently be tethered to the labial mucosa, preventing the patient from adequately maintaining any dental prosthesis. A secondary skin graft vestibuloplasty may be required to restore function and esthetics (Figure 36.1). If postoperative radiation therapy has been employed, skin grafting has a much higher failure rate and may result in osteoradionecrosis of the remaining mandible. Therefore, a skin graft or a mucosal pedicle flap is optimal for resurfacing the anterior floor of mouth defect at the time of the ex-

FIGURE 36.1 Split-thickness skin graft reconstruction of marginal

FIGURE 36.3 Pectoralis major myocutaneous flap reconstruction of

mandibular defect.

marginal mandibular defect.

36. Marginal Mandibulectomy

413

FIGURE 36.4 Radial forearm microvascular flap reconstruction of marginal mandibular defect.

tirpation, obviating any of the serious complications of a secondary reconstructive procedure. Larger defects may require more extensive reconstructions, including pedicled flaps or microvascular tissue transfer.

In the patient who has recurrent tumor or a new primary following irradiation of a prior tumor, a different approach must be used. A skin graft may not heal over a previously irradiated mandible. In this situation, vascularized tissue flaps are preferred (Figure 36.2). Nasolabial flaps, either unilateral or bilateral, can be used to resurface an anterior floor of mouth defect. They have the advantage of bringing vascularized tissue with a defined arterial supply to resurface the exposed mandible. Although these flaps can often be elevated and inset in one procedure, it is occasionally necessary for a secondary procedure to divide the flap pedicles several weeks postoperatively. Platysmal myocutaneous flaps have also been used to reconstruct lateral floor of mouth defects. They can be easily elevated and are fairly reliable, even if performed in conjunction with a radical neck dissection.

More extensive defects, particularly those that include a significant portion of tongue, must be reconstructed with vascularized tissue, either locoregionally or from a distant location (Figure 36.3). The pectoralis major myocutaneous flap has been used frequently in head and neck reconstruction, with varying complication rates. It has the advantage of using nonirradiated tissue to reconstruct a defect, providing

muscle to cover and protect the carotid artery in a patient who has undergone a resection in conjunction with a radical neck dissection. We have found the complication rate to be as high as 75% when a pectoralis flap is used to reconstruct anterior floor of mouth defects. In these situations, we prefer to use a microvascular tissue transfer, such as a radial forearm fasciocutaneous flap to reconstruct the tongue and floor of mouth, as well as to resurface the cut edge of the mandible (Figure 36.4). This flap has the advantage of providing supple tissue which can adapt to the contour irregularities of the defect, permit postoperative dental rehabilitation, withstand postoperative radiation therapy without contraction or dehiscience, and even provide a sensate area to assist in nutritional support.11

References

1.Marchetta FC, Sako K, Murphy JB. The periosteum of the mandible and intraoral carcinoma. Am J Surg. 1971;122: 711–713.

2.McGregor AD, MacDonald DG. Routes of entry of squamous cell carcinoma to the mandible. Head Neck Surg. 1988;10:294– 301.

3.Gilbert S, Tzadik A, Leonard G. Mandibular involvement by oral squamous cell carcinoma. Laryngoscope 1986;96:96–101.

4.Randall CJ, Eyre J, Davies D, Walsh-Waring GP. Marginal mandibulectomy for malignant disease: indications, rationale, and results. J Laryngol Otol. 1987;101:676–684.

5.Shaha AR, Spiro RH, Shah JP, Strong EW. Squamous carcinoma of the floor of the mouth. Am J Surg. 1984;148:455–459.

6.Barttelbort SW, Bahn SL, Ariyan SA. Rim mandibulectomy for cancer of the oral cavity. Am J Surg. 1987;154:423–428.

7.Dubner S, Heller KS. Local control of squamous cell carcinoma following marginal and segmental mandibulectomy. Head Neck. 1993;15:29–32.

8.Pogrel MA. The marginal mandibulectomy for the treatment of mandibular tumors. Br J Oral Maxillofac Surg. 1987;27:132– 138.

9.Shaha AR. Preoperative evaluation of the mandible in patients with carcinoma of the floor of mouth. Head Neck. 1991;13(5): 398–402.

10.Collins SL, Saunders VW. Excision of selected intraoral cancers by use of sagittal inner table mandibulectomy. Otol Head Neck Surg. 1987;97(6):558–566.

11.Dubner S, Heller KS. Reinnervated radial forearm free flaps in head and neck reconstruction. J Reconstr Microsurg. 1992;8(6): 467–468.

37

Reconstruction of Extensive Anterior Defects of the Mandible

Joachim Prein and Beat Hammer

It is well known that reconstruction of lateral mandibular defects is much easier to perform than in the symphyseal area. Although lateral defects of the mandible can be left without reconstruction, symphyseal defects must be reconstructed primarily, whenever possible. Most patients with unreconstructed lateral defects can still function well, although they have a cosmetic disadvantage. This is in sharp contrast to the failure to reconstruct anterior mandibular defects, which results in an oral cripple characterized by disorders of speech, swallowing, and the cosmetic disability known as an Andy Gump deformity (Figure 37.1).

The method of choice for the reconstruction of anterior mandibular defects, even for patients with locally advanced disease, can be considered although it may be palliative, is the free microvascular tissue transfer (usually of composite osteocutaneous flaps). The various publications of the recent years by Schusterman et al., Urken, and others1–11 show clearly that the introduction of microvascular tissue transfer, especially in the head and neck area has helped considerably to diminish the postoperative morbidity of our patients.

Our experience is that reconstruction with plates alone in the lateral aspect of the mandible for a certain time may be satisfactory, but the rate of complications in the symphysis with this method is considerably higher. Often after reconstruction with plates alone of anterior defects, many plate exposures occur no matter how thick the muscle or skin flap coverage.

We began the reconstruction of major defects in the facial area with microvascular flaps as a routine method in 1989. In the beginning, we preferred to use the iliac crest as a donor site. However, in recent years, and with more experience we now prefer either the fibula or the scapula as a donor site. The advantage of the fibula over the iliac crest is because the fibula can be shaped easier, is longer and the vessels, although shorter, have a larger diameter. The iliac crest on the other hand is larger and meets in a more natural manner the angular shape of the mandible in this region. However, donor site

morbidity in the iliac crest is greater than in the lower leg or shoulder area.

Our choice depends on the type of defect (bone only, or bone and soft tissues), the location of the defects (symphysis or lateral aspect), the prognosis for the patient (type of tumor), and the general condition of the patient. In those instances where we use the fibula as a microvascular graft an angiography is performed in all of the patients. Most of our cancer patients are heavy smokers and, owing to severe arteriosclerosis, it may not be possible to harvest the fibula because of the risk of limb loss. As far as the osseous quality, size, and characteristics are concerned, the fibula is superior to the bone that can be harvested from the lateral aspect of the scapula. On the other hand, combined with the bone of the scapula, two soft tissue flaps for an intraoral and extraoral defect closure are available. The scapular myocutaneous flaps are safer than the soft tissue flaps that can be lifted together with the fibula bone.1,2 Fixation of vascularized bone grafts can either be done with reconstruction plates or with smaller microvascular or mini plates3 (see chapter 27, Boyd and Mulholland, 1993).

In contrast, it must be emphasized that fixation of nonvital bone grafts must under all circumstances be performed with reconstruction plates. Cosmetically and functionally the results are much better if the reconstruction can be performed primarily. Although the time of surgery may be longer, the overall morbidity of the patients can be lowered considerably when early definitive reconstruction and subsequent rehabilitation with dental implants is performed (Figures 37.2–37.5). Especially in patients who have to undergo combined therapy of surgery and preor postoperative radiotherapy, reconstruction with microvascular flaps is mandatory. Depending on the economic system in a country primary microvascular reconstruction that shortens the time of rehabilitation may have a great impact on cost-effectiveness as well. The patients need less time of hospitalization, fewer surgical procedures, and are rehabilitated sooner.

414

37. Reconstruction of Extensive Anterior Defects of the Mandible

FIGURE 37.1 Typical Andy Gump deformity with a consequent crippling of the patient. In this case primary reconstruction was not performed because of the poor general condition of the patient. Postoperatively it must be said that this was a misjudgment since the general condition of this patient as a consequence of this severe morbidity deteriorated more rapidly.

415

FIGURE 37.3 Orthopantomogram of this patient postoperatively showing reconstruction of the symphyseal area with a microvascular graft taken from the iliac crest. Dental implants in this case were implanted simultaneously. It is no longer performed this way in our institution, since the primary placement of dental implants is often a disadvantage for the prosthodontist. Fixation was obtained with short reconstruction plates. The one necessary osteotomy of the graft itself was fixed with a 2.0 mini-adaption plate.

FIGURE 37.2 Squamous cell carcinoma of the floor of the mouth and the alveolar crest in the symphyseal area. The tumor had infiltrated the bone. TNM formula: T4 NO MO.

FIGURE 37.4 The patient was provided with new dentures and had an excellent functional result.

416

FIGURE 37.5 The patient remained with his original physiognomy including excellent shaping of his chin area. The patient is now 6 years free of disease.

We have had the opportunity to observe and manage extensive anterior defects of the mandible with a special patient group that we have treated in Basel during the past 25 years. During this period we have seen 33 patients with gunshot wounds of the face. Most of these injuries happened as a consequence of suicidal attempts and mainly caused the loss of the anterior lower and middle facial regions. An example of the considerable progress achieved in facial reconstructive surgery, especially through microvascular techniques and the technique of adequate stable internal fixation with plates and screws, we show two patients from different time periods.

The first patient was treated between 1973 and 1980. This patient had more than 20 operations during 17 hospital stays. Today his hospital bills would amount to 800,000 Swiss francs. Although the cost of treatment in the hospital was much higher than it would be today, the result is absolutely unsatisfactory (Figure 37.6). There is no bony continuity in

J. Prein and B. Hammer

FIGURE 37.6 Frontal view of patient with severe shotgun wound treated between 1973 and 1976. The chin area is inadequately reconstructed with tubular flaps from the shoulder and abdomen. The patient is unable to control his saliva and can not wear dentures, with an Andy Gump deformity.

his symphyseal area, and therefore function of the lips and tongue is insufficient. The patient has considerable problems with eating and was never able to use dentures. In those days, microvascular techniques were not used as a routine and reconstruction plates were still under development. As a result, this patient’s facial skeleton was not reconstructed correctly. The soft tissue defects were closed with tubular flaps from the shoulder and abdomen. The patient remained an invalid and received a disability pension, which is a high burden to the state economy. On top of this, his hospital bill was very high. Cost-effectiveness in this case is unacceptable according to today’s standards.

In contrast to this, we show a patient of 1997 with a comparable injury that resulted from a self-inflicted shotgun wound. This patient was operated on and underwent complete primary reconstruction 6 days after the accident. His reconstruction included extensive fixation of all facial bones with

37. Reconstruction of Extensive Anterior Defects of the Mandible

FIGURE 37.7 Severe self-inflicted shotgun wound with extensive panfacial fractures and soft tissue loss.

AO titanium plates and screws together with a microvascular forearm flap for the reconstruction of his chin area. It also included extensive reconstruction with free bone grafts since the soft tissue coverage of the bones was adequate. Surgery lasted 23 hours (surgeon: Dr. Beat Hammer) (Figures 37.7–37.9). The hospital bill of this patient was 80,000 Swiss francs, one tenth of the bill for the patient treated in 1973 with a similar shotgun wound. In Switzerland, the hospital fee per day is always the same, regardless of the treatment performed, and as a result the hospital incurs a severe financial loss with these types

417

FIGURE 37.8 Extensive reconstruction of the patient’s panfacial fractures with good facial projection as a result. No Andy Gump deformity.

of highly expensive, lengthy, and complicated operations. As a result of primary reconstruction with microvascular tissue transfer, rehabilitation time for this patient is short, and he will not remain a permanent invalid, as did our first patient. The postoperative social costs for this patient are therefore much lower. The ratio of cost-effectiveness is very good, although the surgical costs including the implants are very high.

Our complete results with 43 patients with shotgun lacerations during the last 25 years has been published in a separate paper.12

418 J. Prein and B. Hammer

References

1.

Schusterman MA, Reece GP, Kroll StS, Weldon ME. Use of

 

 

 

 

 

the AO-plate for immediate mandibular reconstruction in can-

 

 

 

 

 

cer patients. Plast Reconstr Surg. 1991;88:588–593.

2.

Schusterman MA, Reece GP, Miller MJ, Harris S. The osteo-

 

 

 

 

 

cutaneous free fibula flap: is the skin paddle reliable? Plast Re-

 

 

 

 

 

constr Surg. 1992;90:787–793.

3.

Boyd JB, Mulholland RS. Fixation of the vascularized bone graft

 

 

 

 

 

in mandibular reconstruction. Plast Reconstr Surg. 91:274–282

 

 

 

 

 

(1993).

4.

Buchbinder D, Urken ML, Vickery C, Weinberg H, Biller HF.

 

 

 

 

 

Bone contouring and fixation in functional, primary microvas-

 

 

 

 

 

cular mandibular reconstruction. Head Neck. 13:191 (1991).

 

 

 

 

 

 

 

5.

Fu-Chan W, Hung-Chi CH, Chwei-Chin CH, Noordhoff MS.

 

 

 

 

 

 

Fibular osteoseptocutaneous flap: anatomic study and clinical

 

 

 

 

 

application. Plast Reconstr Surg. 78:191–199 (1986).

6.

Hammer B, Prein J, Ettlin D. Fixation of microvascular grafts

 

 

 

 

 

for mandibular reconstruction: mini-plate versus reconstruction-

 

 

 

 

 

plate. J Craniomaxillofac Surg. Vol 24 (Suppl. 1):51 (1996).

7.

Hidalgo DA. Fibula free flap: a new method of mandible re-

 

 

 

 

 

construction. Plast Reconstr Surg. 84:71–79 (1989).

8.

Riediger D. Restoration of masticatory function by microsurgi-

 

 

 

 

 

cally revascularized iliac crest bone grafts using enosseous im-

 

 

 

 

 

plants. Plast Reconstr Surg. 6:861–876 (1988).

9.

Swartz WM, Banesi JC, Newton ED, Ramasastry SS, Joes NF,

 

 

 

 

 

Acland R. The osteocutaneous scapular flap for mandibular and

 

 

 

 

 

maxillary reconstruction. Plast Reconstr Surg. 1986;77:530–545.

10.

Taylor G, Townsend P, Coriett R. Superiority of the deep cir-

FIGURE 37.9 Patient’s view approximately 10 days after surgery. Re-

cumflex iliac vessels as the supply for free groin flaps. Plast Re-

constr Surg. 1979;64:595.

construction of the soft tissue defect in the chin area with a mi- 11.

Urken ML. Composite free flaps in oromandibular reconstruc-

crovascular forearm flap.

tion. Review of the literature. Arch Otolaryngol Head Neck

 

 

 

 

 

Surg. 1991;117:724.

12.

Prein J, Schwenzer N, Hammer B, Ehrenfeld M: Gunshot in-

 

 

 

 

 

juries of the mandible. Fortschr Kiefer Gesichtschir. 1996;41:

 

 

 

 

 

160–165.