Surgical Management of Oral Pathologic Lesions

Indications

Enucleation is the treatment of choice for removal of cysts of the jaws and should be used with any cyst of the jaw that can be safely removed without unduly sacrificing adjacent structures.

Advantages

The main advantage to enucleation is that pathologic examination of the entire cyst can be undertaken. Another advantage is that the initial excisional biopsy (i.e., enucleation) has also appropriately treated the lesion. The patient does not have to care for a marsupial cavity with constant irrigations. Once the mucoperiosteal access flap has healed, the patient is no longer bothered by the cystic cavity.

Disadvantages

If any of the conditions outlined under the section on indications for marsupialization exist, enucleation may be disadvantageous. For example, normal tissue may be jeopardized, fracture of the jaw could occur, devitalization of teeth could result, or associated impacted teeth that the clinician may wish to save could be removed. Thus each cyst must be addressed individually, and the clinician must weigh the pros and cons of enucleation versus marsupialization (with or without enucleation; see “ Enucleation After Marsupialization ”).

Technique

The technique for enucleation of cysts was described in Chapter 21 ; however, the clinician must address special considerations. The use of antibiotics is unnecessary unless the cyst is large or the patient's health condition warrants it (see Chapters 1 and 2 ).

The periapical (i.e., radicular) cyst is the most common of all cystic lesions of the jaws and results from inflammation or necrosis of the dental pulp. Because it is impossible to determine whether a periapical radiolucency is a cyst or a granuloma, removal at the time of the tooth extraction is recommended. If, however, the tooth is restorable, endodontic treatment followed by periodic radiographic follow-up allows assessment of the amount of bone fill. If none occurs or the lesion expands, the lesion probably represents a cyst and should be removed by periapical surgery. When extracting teeth with periapical radiolucencies, enucleation via the tooth socket can be readily accomplished by using curettes when the cyst is small ( Fig. 23.4 ). Caution is used in teeth with apices that are close to important anatomic structures such as the inferior alveolar neurovascular bundle or the maxillary sinus because the bone apical to the lesion may be very thin or nonexistent. With large cysts, a mucoperiosteal flap may be reflected and access to the cyst obtained through the labial plate of bone, which leaves the alveolar crest intact to ensure adequate bone height after healing ( Fig. 23.5 ).

Once access to a cyst has been achieved through the use of an osseous window, the dentist should begin to enucleate the cyst. A thin-bladed curette is a suitable instrument for cleaving the connective tissue layer of the cystic wall from the bony cavity. The largest curette that can be accommodated by the size of the cyst and of the access should be used. The concave surface should always be kept facing the bony cavity; the edge of the convex surface performs the stripping of the cyst. Care must be exercised to avoid tearing the cyst and allowing the cystic contents to escape because margins of the cyst are easier to define if the cystic wall is intact. Furthermore, the cyst separates more readily from the bony cavity when the intracystic pressure is maintained.

In large cysts or cysts proximal to neurovascular structures, nerves and vessels are usually found pushed to one side of the cavity by the slowly expanding cyst and should be avoided or handled as atraumatically and as little as possible. Once the cyst has been removed, the bony cavity should be inspected for remnants of tissue. Irrigating and drying the cavity with gauze aids in visualizing the entire bony cavity. Residual tissue is removed with curettes. The bony edges of the defect should be smoothed with a file before closure.

Cysts that surround tooth roots or are in inaccessible areas of the jaws require aggressive curettage, which is necessary to remove fragments of cystic lining that could not be removed with the bulk of the cystic wall. Should obvious devitalization of teeth occur during a cystectomy, endodontic treatment of the teeth may be necessary in the near future, which may help prevent odontogenic infection of the cystic cavity from the necrotic dental pulp.

After enucleation, a watertight primary closure should be obtained with appropriately positioned sutures. The bony cavity fills with a blood clot, which then organizes over time. Radiographic evidence of bone fill will take 6 to 12 months. Jaws that have been expanded by cysts slowly remodel themselves to a more normal contour.

If the primary closure should break down and the wound open, the bony cavity should then be packed open to heal by secondary intention. The wound should be irrigated with sterile saline, and an appropriate length of strip gauze lightly impregnated with an antibiotic ointment should be gently packed into the cavity. This procedure is repeated every 2 to 3 days, gradually reducing the amount of packing until no more is necessary. Granulation tissue is seen on the bony walls in 3 to 4 days and slowly obliterates the cavity and obviates the need for packing. The oral epithelium then closes over the top of the opening, and osseous healing progresses.

Indications

The following factors should be considered before deciding whether a cyst should be removed by marsupialization:

• 1

  Amount of tissue injury. Proximity of a cyst to vital structures can mean unnecessary sacrifice of tissue if enucleation is used. For example, if enucleation of a cyst would create oronasal or oroantral fistulae or cause injury to major neurovascular structures (e.g., the inferior alveolar nerve) or devitalization of healthy teeth, marsupialization should be considered.

• 2

  Surgical access. If access to all portions of the cyst is difficult, portions of the cystic wall may be left behind, which could result in recurrence. Marsupialization should therefore be considered.

• 3

  Assistance in eruption of teeth. If an unerupted tooth that is needed in the dental arch is involved with the cyst (i.e., a dentigerous cyst), marsupialization may allow its continued eruption into the oral cavity ( Fig. 23.7 ).

  

• 4

  Extent of surgery. In a patient with ill health or any debilitation, marsupialization is a reasonable alternative to enucleation because it is simple and may be less stressful for the patient.

• 5

  Size of cyst. In very large cysts, a risk of jaw fracture during enucleation is possible. It may be better to perform marsupialization of the cyst and defer enucleation until after considerable bone fill has occurred.

Advantages

The main advantage of marsupialization is that it is a simple procedure to perform. Marsupialization may also spare vital structures from damage should immediate enucleation be attempted.

Disadvantages

The major disadvantage of marsupialization is that pathologic tissue is left in situ, without thorough histologic examination. Although the tissue taken in the window can be submitted for pathologic examination, a more aggressive lesion may be present in the residual tissue. Another disadvantage is that the patient is inconvenienced in several respects. The cystic cavity must be kept clean to prevent infection because the cavity frequently traps food debris. In most instances, this means that the patient must irrigate the cavity several times every day with a syringe. This may continue for several months, depending on the size of the cystic cavity and the rate of bone fill.

Technique

Prophylactic administration of systemic antibiotics is not usually indicated in marsupialization, although antibiotics should be used if the patient's health condition warrants it (see Chapters 1 and 2 ). After anesthetization of the area, the cyst is aspirated as discussed in Chapter 21 . If the aspirate confirms the presumptive diagnosis of a cyst, the marsupialization procedure may proceed ( Fig. 23.8 ). The initial incision is usually circular or elliptical and creates a large (1 cm or larger) window into the cystic cavity. If the bone has been expanded and thinned by the cyst, the initial incision may extend through bone into the cystic cavity. If this is the case, the tissue contents of the window are submitted for pathologic examination. If overlying bone is thick, an osseous window is removed carefully with burrs and rongeurs. The cyst is then incised to remove a window of the lining, which is submitted for pathologic examination. The contents of the cyst are evacuated, and if possible, visual examination of the residual lining of the cyst is undertaken. Irrigation of the cyst removes any residual fragments of debris. Areas of ulceration or thickening of the cystic wall should alert the clinician to the possibility of dysplastic or neoplastic changes in the wall of the cyst. In this instance, enucleation of the entire cyst or incisional biopsy of the suspicious area or areas should be undertaken. If the cystic lining is thick enough and if access permits, the perimeter of the cystic wall around the window can be sutured to the oral mucosa.

Otherwise the cavity should be packed with strip gauze impregnated with tincture of benzoin or an antibiotic ointment. This packing must be left in place for 10 to 14 days to prevent the oral mucosa from healing over the cystic window. By 2 weeks, the lining of the cyst should be healed to the oral mucosa around the periphery of the window. Careful instructions to the patient regarding cleansing of the cavity are necessary.

With marsupialization of cysts of the maxilla, the clinician has two choices of where the cyst will be brought to the exterior: (1) The cyst may be surgically opened into the oral cavity, as just described, or (2) it may be opened into the maxillary sinus or nasal cavity. In the case of a cyst that has destroyed a large portion of the maxilla and has encroached on the antrum or nasal cavity, the cyst may be approached from the facial aspect of the alveolus, as just described. Once a window into the cyst has been made, a second unroofing can be widely performed into the adjacent maxillary antrum or nasal cavity. (If access permits, the entire cyst can be enucleated at this point, which allows the cystic cavity to become lined with respiratory epithelium that migrates from the adjoining maxillary sinus or nasal cavity.) The oral opening is then closed and allowed to heal. The cystic lining is thereby continuous with the lining of the antrum or nasal cavity.

Marsupialization is rarely used as the sole form of treatment for cysts. In most instances, enucleation is done after marsupialization. In the case of a dentigerous cyst, however, no residual cyst may exist to be removed once the tooth has erupted into the dental arch. In addition, if further surgery is contraindicated because of concomitant medical problems, marsupialization may be performed without future enucleation. The cavity may or may not obliterate totally with time. If it is kept clean, the cavity should not become a problem.