Posted in Dento-alveolar

Oroantral Fistula

OROANTRAL FISTULA

Introduction

A fistula ( ‘Latin’ = a pipe or tube ) is an abnormal communication between the lumen or surface of one organ and the lumen or surface of another or between vessels. Most fistulas connect epithelial lined surfaces. Fistulas may be congenital or acquired.

Oroantral fistula ( OAF ) is a relatively uncommon complication of maxillary molar extraction. Other causes of perforation into sinus include destruction of a portion of the sinus following facial bone fractures, periapical lesions, removal of large cystic cavity that encroach on sinus cavity and in cleft patients. OAF occur as a result of failure in healing of Oroantral communication ( OAC ). Although most acute OAC heal spontaneously or after minor surgical procedures, some do persist and result in an OAF following failure in primary healing.

Anatomical & Embyologic considerations

The proximity of maxillary sinus to the dentition of upper jaw makes it highly susceptible to development of Oroantral communication. The floor of the maxillary sinus (formed by the junction of the anterior and lateral sinus wall) in adults is approximately 1 to 1.25 cm below the level of the floor of the nasal cavity. It sometimes encompasses the alveolar process and the roots of molars and premolars. These projection into the antrum are sometimes not covered by bone but only by mucoperiosteum. The distance between the apices of the teeth and the floor of the maxillary antrum varies depending on the amount of intervening bone.

In children and young teenagers whose maxillary sinus has not reached the adult size, the floor of the sinus is at a considerable distance from the apices of the maxillary teeth. So creating an OAC or accidental dislodgement of root tips into the maxillary sinus is unlikely in younger individuals. In older persons, the distance between the roots of teeth and maxillary sinus is only very minimal or root projects into the sinus. The root of maxillary second molar is closest followed by first molar, third molar, second premolar, first premolar and canine.

Developmentally, maxillary sinus is the first paranasal sinus to develop at 3rd month of intrauterine life. Prenataly it has two phases, primary and secondary pneumatisation phases. In primary pneumatisation the sinus cavity lies in the nasal capsule. In secondary pneumatisation phase the sinus grows into the maxilla. At birth the sinus is 7mm Anteroposteriorly, 4mm in height and 4mm in width, with a volume of 6 to 8 ml. Postnataly the sinus grows at approximately 2mm vertically and 3mm anteroposteriorly. It has got three growth spurts birth to 2.5 yrs, 7.5 yrs to 10 yrs and 12 yrs to 14 yrs. At 15 to 20 yrs the volume of sinus is abut 15 to 20 ml.

Incidence

The incidence of residual OAF following OAC due to tooth extraction is small due to marked healing ability of alveolar bone. OAF generally occurs when there is

  1. Infection in the antrum
  2. Defect is larger than 5mm in diameter
  3. The gingival tissues are not approximated
  4. Wound dehiscence
  5. Patient does not follow post operative instructions.
  6. Large surgical defect following removal of a cyst or neoplasm that encroaches on the sinus.

There is male predominance of  2 : 1 with a peak age distribution in the third and fourth decades because the sinus tends to be larger and the alveolar bone is denser in men.

The predisposing factors for Oroantral communication are

  1. The relationship of unerupted teeth or roots to maxillary Removal of submerged premolars or molars have high chance for Oroantral communication.
  2. Abnormality in size and shape of tooth roots. Hypercementosis of roots, bulbous roots result in difficult extraction and can result in Oroantral communication.
  3. Extraction of lone long standing maxillary molars where the maxillary sinus has grown into the alveolus.
  4. Nature of supporting bone. Sclerosed bone result in difficult extraction and may result in Oroantal communication.
  5. Loss of periapical bone due to periapical granuloma or cyst.
  6. Surgical procedures for removal of large cyst or tumours that encroach upon the sinus.
  7. Iatrogenic causes include incorrect use of dental elevators.

Pathogenesis and clinical features.

An Oroantral communication/penetration will often heal spontaneously and hardly they become chronic fistulas. Factors affecting healing of Oroantral fistula are

  1. Thickness of supporting bone – it should be adequate between the sinus and the mouth, so that the socket is of sufficient depth for fibrous repair to take place in the socket.
  2. Size of the bony defect – Smaller defects heal better. Defects of more than 5mm in diameter will usually result in formation of fistula.
  3. Wound approximation – If the gingival tissues are not approximated or when there is wound dehiscence, there is increased chance for communication.
  4. Presence of infection in and around the socket.
  5. Raised air pressure in the antral or oral cavity. This disrupts the formed clot.

If the Oroantral communication is unrecognised, untreated or spontaneous closure does not occur then it results in chronic fistula. Contamination of the antrum with infected oral fluids and food debris leads inevitably to chronic sinusitis.

The signs and symptoms of are varied depending on the size of the fistulous opening and infection

In small residual defects (pin hole defects) the consequences are slight and symptoms arise only when there is upper respiratory tract infection. The mucopurulent phase is more marked on the narrow side of the fistula leading to a purulent maxillary sinusitis which persists when all other signs of illness subsides.

Fistulas of intermediate size tend to be a source of recurrent (infection) irritant / symptoms. It is usually associated with intermittent episodes of pain and local tenderness along with a chronic, foul tasting discharge. Drainage may be obstructed by an oedematous lining or by polyps which can prolapse through the fistula into the mouth. The polyps might be large and are lined by stratified squamous epithelium which might be mistaken for granuloma.

Conversely with very large defects, there is free drainage, even though there is reflux of food, drink and saliva. Occlusion of the opening with denture or plate might prevent the entry of food particles into the antrum. Retention of full denture is adversely affected due to lack of seal.

Diagnosis

The first clue to the occurrence of a fistula is likely to be recognised by the presence of antral floor attached to the extracted tooth. The presence of thin, smooth curved plate of bone is characteristic.

When patient blows with occluded nostril in case of OAC it results in bubbling of blood in the socket. Blood trickling from the nostril of the extracted side also confirms the presence of an OAC.

It is better to avoid use of suction or probing the OAC as it might dislodge the established clot and carry the risk of infection into the wound.

If a fistula is formed during the course of extraction of a root then a characteristic hollow sound is produced when suction is used due to an echo from the sinus.

Radiographic features

Periapical, oblique occlusal or rotational tomographic radiographs will demonstrate the defect in the bony floor of the antrum. These are not essential unless fractured fragments are suspected.

Occipitomental / PNS view radiograph will reveal the status of the sinus but floor of the sinus cannot be visualised. Immediately following an OAC little changes will be seen unless there is pre-existing sinusitis which is seen as opacity or a fluid level. In few instances a pre-existing cyst or neoplasm might be the cause for OAF.

In chronic OAF there is generalised mucosal thickening or opacity of sinus in PNS view.

Management

The management consist of an early treatment for acute OAC and treatment for chronic fistula with some supportive measures.

Management of acute oro antral communication

Acute Oroantral communication is managed by socket edge reduction with simple / horizontal mattress suturing, with use of supportive pack or plate along with prophylactic use of antibiotics, antihistamines and nasal decongestants for 7 to 10 days.

Socket edge reduction and suturing

The buccal mucosa is reflected and reduction of the buccal wall of socket done by use of roungers. This allows the buccal mucoperiosteum to fall medially. It is then sutured in place with palatal side by horizontal mattress suturing.

Use of supportive packs or protective plate

Supportive packs or plate result in healing by secondary intention. Use of hemostatic packs ( Surgicel, gelfoam ) are to be avoided. Supportive packs soaked in antiseptic agent like Bismuth-Iodoform-paraffin paste (BIPP) is suspended across the socket and sutured in place. They are kept for 2 weeks. Protective plate kept for a limited period prevents the food particles from being forced in through the socket.

All these procedures should be accompanied by restriction in nose blowing to avoid raise in air pressure in the antrum so as to protect the clot until healing is complete.

It is better to put these patients on antibiotics like penicillins, antihistamines and nasal decongestants for 7 to 10 days to prevent infection.

The majority of the patients treated in this manner will have uneventful healing of OAC if they do not have pre-existing sinusitis.

Management of chronic / established fistulas or Large OAC

Oroantral communication of long duration will expose the sinus to salivary secretions and food debris. This will result in chronic irritation changes in the lining, produce infection and disturb ciliary function. So early closure of these communications are vital.

There are certain contraindications to immediate surgical closure for OAC.

  1. Degree of soft tissue damage following extraction. Macerated and oedematous adjoining oral tissue prevents early closure and it is better to leave the fistula for 3 to 4 weeks. In cases of minimal trauma to the mucoperiosteum, closure can be performed after 48 hrs.
  2. Infection in antrum. A clean sinus with healthy antral mucosa is a prerequisite for successful closure of any Oroantral communication. Condition of the antrum can be assessed by Occipitomental ( PNS ) view radiographs which might show mucosal thickening or cavity obliteration. In cases of long standing history of sinusitis the closure should be accomplished with an intranasal antrostomy to establish drainage.

Fistulae that have been open for weeks will show hyperplastic polypoidal changes in the antrum and metaplastic changes to squamous epithelium. This can be treated by local removal of sinus lining at the time of attempted closure.

In case of  sinusitis, the fistula is managed conservatively and delayed closure is done. Conservative treatment consists of daily antral lavage through the socket. The socket may be enlarged for this purpose. Over 4-6 weeks the infection should subside and spontaneous closure might occur.

Surgical closure of Oroantral fistula

In cases of healthy antrum and small fistula, closure is usually spontaneous. However in large defects surgical closure is required. Many authors have described various surgical techniques, starting with Durham in 1893 who advocated vascularised soft tissue pedicle flap for closure of these defects. Other procedures carried out include sliding buccal flaps with or without bone grafts, palatal pedicle flaps and combination of buccal and palatal flaps. Allograft such as gold foil, titanium foil, gold plate, tantalum plate, Gore-tex membrane, Hydroxyapatite block and soft methyl methacrylate have been used.

Surgical procedures carried out can be classified into


Surgical closure of Oroantral fistula

  1. Local flaps
  2. Buccal flaps
  • Advancement flap (Welty, Von Rehrmann & Berger).
  • Modified advancement (Laskin & Robinson)
  • Sliding flap (Moczair)
  1. Palatal flaps
  • Straight advancement
  • Rotational advancement
  • Hinging and Island flaps
  • Palatal submucosal connective tissue flap.
  1. Bridge flap
  2. Combined local flaps
  • Double flap
  1. Distant flaps
  2. Tongue flaps
  • Anteriorly based
  • Posteriorly based
  • Laterally based
  1. Temporalis muscle flap
  2. Buccal fat pad flap
  3. Osteoperiosteal flap
  4. Grafts
  5. Autogenous bone grafts
  6. Allografts
  • Gold foil.
  • Tantulum foil
  • Gold plate
  • Poly methyl methacrylate
  • Hydroxy apatite blocks.
  • Fibrin glue.

LOCAL FLAPS

Various flap have been used  for closure of oroantral fistula. The basic requirement of flaps are

  1. The flap should not only cover the fistula but also a ledge of bone which will support the suture line.
  2. The flap should have a good blood supply and should be handled gently and not grasped or crushed with dissecting forceps.
  3. The flap should be sutured without tension.
  4. The flap is to be sutured only after achieving complete hemostasis, as haematoma creates tension, delays healing and also acts as a nidus for infection.

Failures occur when there are neglected and also for anatomic reasons.

Buccal Flaps

Many small defects can be closed by means of buccal mucoperiosteal flaps. Two types of buccal flaps have been used

  1. Advancement flap
  2. Sliding flap
Buccal advancement flap

This is the most commonly used buccal flap. It was first described by Welty (1920) and Von Rehrmann (1936) and popularised by Berger (1939).

This flap is used to close

  1. An established Oroantral fistula.
  2. A newly created Oroantral communication at the time of extraction.
  3. An Oroantral fistula in combination with exploration of maxillary sinus to remove displaced root.
Procedure

This can be performed under local anaesthesia.

The tissue that form the rim of the fistula is excised from the edge of the opening with a No:11 BP blade exposing the rim of bone which acts as a supporting shelf for the flap. The palatal margin is undermined for 2 to 3 mm to ease suturing.

From the extreme end of buccal aspect two diagonal incisions are made through buccal mucoperiosteum. The incisions are carried into upper mucobuccal fold in a curvilinear manner. The flap is raised exposing the bonny defect. On the under surface of the flap the periosteum is incised horizontally at different levels. Care is taken not to disrupt the vascularity. This aids in stretching /extending the flap over the defect. The corners are trimmed and the flap is sutured in place. Two plain sutures are given at the medial and distal angles of the flap. A horizontal mattress is given in between them to evert wound margin and ensure a broad area of apposition of tissues. The flap should be sutured without tension or ischaemic margin, which will cause necrosis and failure in healing. Sutures are placed along the buccal limits of incision.

Ideally 4-o absorbable sutures are used but in cases where non-absorbable black silk or prolene are used it should not be removed before 10 days.

If gingival margins are included, it should be wide enough to form a everted margin on the adjacent tooth. In cases where there is no adjacent teeth the mesial and distal mucosa can be removed so that flaps rests on a distinct shelf of bone.

Advantages

It has the advantage of a broad base so providing a good blood supply. There is no denuded area left behind and also no requirement for rotation. Simultaneous Caldwell – Luc procedure can be performed either directly or by extending the incision anteriorly into canine fossa.

Disadvantages

This procedure is usually associated with reduction of buccal vestibule. Von Wowern (1972) pointed that sulcus reduction gets minimised by 6 months as the buccal sulcus reshapes in 4 to 8 weeks.

Modification

Laskin and Robinson (1956) described a modification of the buccal flap that provides a surface to surface approximation and thus assures closure even if a portion of the flap devitalises. Here instead of removing the entire mucoperiosteum on the palatal side, only the epithelium is removed. The tissue lining the fistula are not removed as this enlarges the opening. By this way, a box like preparation lined with fresh connective tissue extending on to the palatal side of the alveolar process for at least 5mm beyond the edge of the opening is created and the flap is placed onto this area.

Another modification is the use of buccal fat pad advancement along with this flap. This is accomplished surgical manoeuvre with no obvious advantages.

Buccal sliding flap

This trapezoidal sliding buccal flap to close Oroantral fistula was described by Moczair in 1930. This produces minimal change in the depth of the buccal vestibule. The distal shift if the flap is fabricated by incising the periosteum at the base of the flap. This flap is suitable in edentulous condition.

The disadvantages of this flap being a raw area is left anteriorly or posterioly and large amount of gingival attachment is needed to facilitate the shift, which might result in gingival recession and periodontal disease.

Palatal Flaps

The palatal flaps used for OAF closure are

  1. Straight advancement flap.
  2. Rotation advancement flap.
  3. Hinged and island palatal flaps based on the greater palatine vessels.
  4. Palatal submucosal connective tissue flap.

The advantages of palatal flaps are its vasculature and its thickness which resembles attached gingiva on the crest of ridge.

The disadvantages are the need for rotation with attendant risk of decreasing the blood supply and the raw donor surface that has to heal secondarily.

Palatal straight advancement flap.

This flap is of limited use due to inelastic nature of the palatal tissue reduces its lateral mobilisation. Sop it is preferable to use rotation advancement flap.

Palatal rotational advancement flap

This flap is based on the greater palatine artery. This was described by Dunning (1925) and Ashey (1939).

Indications
  1. When the oroantral fistula is related to the palatal side of the ridge.
  2. When buccal procedures have failed usually because of considerable ridge resorption.

The palatal mucosal tissue is firmly adherent to the underlying periosteum from which separation is difficult. This makes palatal flap thick and inelastic so that it must be made longer than would appear unnecessary. Only limited rotation can be performed without twisting the palatine artery. It is not recommended for areas posterior to second molar as this would devitalise the flap due to twisting of the artery. This flap can be used to close contralateral oroantral fistula/ communication posterior to second molars.

Procedure

The procedure involves dissecting out fistula to expose 4mm of bone all around the defect. The palatal margin is made to coincide with lateral edge of palatal flap.

The incision for the flap is made along the midpalatal line just anterior to junction of hard and soft palate anteriorly and curved laterally back towards the affected side in the canine region. The incision is continued backwards by about 4mm behind the distal end of the fistula. The flap is lifted and detached from the palate antero-posteriorly until it can be sutured laterally over the fistula without tension.

The denuded bone anteriorly is covered with gauze soaked in antiseptic solution. Sutures are retained for a period of 10 days and pack for 3 weeks. The palatal surface regains its normal appearance in 2 months.

Kruger has suggested a ‘V’ shaped excision of tissue on the lesser curvature to minimise folding the flap. Care has to be taken to avoid damage to greater palatine vessels.

Palatal island flap.

Here an island of palatal mucosa along with greater palatine artery is dissected out and it is used to close the defect. This was first described by Brosch (1950). Millard (1962), Moore & Chong (1967) described a modification where the greater palatine neurovascular bundle is dissected till the foramen using Mc Indoe scissors. This provides some extension to the flap. Twisting is very much reduced by virtue of its length but care with manipulation of the vascular bundle should not be compromised ( Henderson, 1974 ).

James has suggested that sectioning of the island flap to be done last so that the tissue can still be used as a rotational advancement flap or returned to its original site should there be injury to the vessel during the preparation of the flap.

Gullane and Arena have described a modification of the island flap that obtains approximately 1cm of extra length by freeing the vessel at the greater palatine foramen.

Hinged flap

The mucoperiosteum on the palatal aspect of the OAF can be used as a hinged flap to close small openings. The proximity of the distal edge of the flap to the palatal vessels limits its length, therefore it cannot be used unless the opening is on the palatal side of the alveolar ridge.

Palatal submucosal connective tissue flap

This was described by Ito & Hara (1980). Here after elevation of the full thickness palatal flap, a submucosal connective tissue with artery and periosteum is used to close the fistula and return the remainder tissue to close the donor site.

Although this procedure eliminates the donor site defect, dissection of the submucosal flap is often difficult and requires great care to avoid injury to the palatal vessels that supply the flap.

Bridge Flap / Buccopalatal flap.

This is useful in cases of edentulous maxilla (Kazanjian 1949, Schuchardt 1953 ) . Here a local bridge of tissue in an area adjacent to fistula may be moved to cover it. After excision of fistulous tract incisions are placed transversely across the line of the arch. The length of the bridge of mucoperiosteum is limited on the palatal end by the palatine artery. It can be extended buccally sufficient to elevate and lift it over the fistula without tension. It is then sutured to the undisturbed edge of the mucoperiosteum on the distal edge of the defect. The bridge must be wider than the defect and broad enough to be well seated on bone. Size of the fistula must be assessed prior to incision for bridge is made. The denuded bone of the donor area will granulate and heal secondarily. There is no reduction in buccal vestibular depth.

Combined local flaps.

Closing larger defects with single local flaps have led to failures and for these situations double layered closures have been used. These include a

  1. Combination of inversion and rotational advancement flaps.
  2. Double overlapping hinge flaps.
  3. Double island flaps.
  4. Superimposed reverse palatal and buccal flaps.

All these procedures except that described by Ziemba (Superimposed reverse palatal and buccal flaps) preserve the buccal vestibule depth. The use of two donor sites results in an increased surgical time and a larger denuded area.

DISTANT FLAPS

The limited size of local flaps make it difficult to close large fistulas, therefore distant flaps have been used for this purpose. In the past flaps from the extremities and forehead have been used. All these nave been replaced by Tongue flaps, Temporalis flap and buccal fat pad flap.

Tongue flap.

The tongue is an excellent donor site for oral soft tissue reconstruction because of its abundant vascularity. In 1956 Klopp and Schurter described the use of a lateral tongue flap for repair of a soft palatal defect secondary to surgical excision of a malignancy. In 1964 Guerrrero Santos et al used tongue flaps for lip reconstruction. Golden and colleagues (1976), Siegel associates (1977) and Carlesso et al (1980) have demonstrated the safety and success of tongue flaps for reconstruction of palatal defects. Masseng et al (1970) have found no adverse effect due to the use of pedicle tongue flaps for reconstruction of lip and palatal defects on speech articulation or tongue function. Lore et al described a posteriorly based tongue flap to line hypopharynx after total laryngectomy.

Although these flaps can be taken from the dorsum or the lateral border, the lateral border flaps are ideal because of their proximity to the fistula. The tongue flaps used for OAF closure might be Antreriorly based or Posteriorly based. These procedures are usually done under General Anaesthesia.

Dorsal pedicle tongue flap.

About 2/3rd of the width of the tongue can be utilised (2 cm ).

The length of the flap is designed in such a way that 1-2 cm of additional tissue would span the posterior edge of the palatal defect. The width of the flap may be dictated by the width of the flap plus 20%. It is mucocutaneous flap and includes about 2mm of the muscle for adequate vascularity. The flap is then elevated, rotated forward and sutured to the raw edges of the defect anteriorly and laterally. The defect on the tongue may be closed primarily with vertical mattress sutures. At two weeks the flap may be divided under local anaesthesia and set into the posterior aspect of palatal defect. During the post operative period the patient is given liquid diet in the first 24 hours and advanced slowly to amore solid diet..

The anteriorly based tongue flap has the disadvantages of tethering the mobile tongue during healing, but this does not occur with a posteriorly based flap.

Advantages of tongue flap.
  1. This is a highly vascularised flap.
  2. This has a broad based pedicle.
  3. This flap is extremely pliable.
  4. This flap can be easily placed free of tension on most areas of the hard and soft palate.

Thus the pedicled tongue flap is indicated in cases where oroantral fistula cannot be closed with local buccal or palatal flaps because of size or position.

Temporalis muscle flap.

This is another distant flap, which can be used for closure of defects in orofacial region. The temporalis muscle flap has been indicated for one stage closure of large oroantral communications for

  1. The proximity of the temporalis muscle to the oral cavity.
  2. The safety of its vascular pedicle.
  3. Its pliability.
  4. The minimal functional and aesthetic sequelae.
Procedure

The muscle is approached through a hemicoronal incision, the flap is outlined and the temporalis fascia is sectioned above the arch to permit flap rotation. It is then brought into the oral cavity through a tunnel created in the infra temporal fossa. This can be facilitated by removing a section of zygomatic arch, which is replaced and fixed with miniplate after the passage of the flap. When necessary the coronoid process is sectioned to increase the arc of rotation and the length of the flap.

Advantages

This flap has the advantage over the tongue flap of causing less dysfunction during the healing period and providing the ability to close larger defects. Epithelisation occurs in 2 to 3 weeks.

Buccal fat pad

The buccal fat pad ( BFP) is a mass of specialised fatty tissue distinct from subcutaneous fat. This tissue was first recognised by Bichat in 1802. The BFP is located between the buccinator muscle and the mandibular ramus, separating the masticatory muscles from each other. It is surrounded by a fascial envelope. In the infants this prevents indrawing of the cheeks during suckling and in the adult it enhance the intermuscular motion.

The use of buccal fat pad as a pedicled graft for closure of oroantral communication was first described by Egyedi 1977 with split skin graft cover. Its use as a free graft was reported by Neder 1983. Fideman et al 1986 first described the use of uncovered BFP a s a pedicled graft in the mouth and showed that healing occurred within 2-3 weeks leaving a good mucosal surface. A large series of 56 cases of use of BFP for closure of OAF have been published by Stajcic Z. 1992.

Surgical anatomy

The buccal fat pad has a central body with four extensions. The main body lies above the parotid duct on the anterior border of the masseter muscle and extends deeply to lie on the maxilla and forward along the buccal vestibule.

The buccal extension is the most superficial and enters the cheek below the parotid duct. It descends to the mandibular retromolar region and overlies the main part of the buccinator muscle.

The pterygoid extension passes down and back to lie on the lateral surfaces of the pterygoid plates.

The temporal extension passes upward below the zygomatic arch and comprises a deep and superficial portion. The deep part lies on the temporalis muscle, tendon and It separates it from the zygomatic arch.

The blood supply of the BFP is from the buccal and deep temporal branches of the maxillary artery, the superficial temporal artery through the transverse fascial branch and small branches of the fascial artery.

The body and buccal extension (50% of total volume) are accessible through the mouth and available as a pedicled graft. It is readily accessible through an horizontal vestibular incision in the third molar region. The fat pad is then gently teased out of its bed and advanced into the defect, where it is sutured in place. It can be left as such or covered with buccal flap, split skin or lyophilised porcine dermis. Uncovered fat pad epithelises in 2 – 3 weeks.

Advantages
  1. This has got rich vascular supply.
  2. Ease of access and close proximity of the donor site to the defect.
  3. Reliable method for the reconstruction of defects up to 4cm in diameter, on the ipsilateral side of the soft palate and posterior alveolar region of the maxilla. Histology of healed tissue showed epithelialisation to 6 – 8 mm with no fat cells.

Osteoperiosteal flap

An osteoperiosteal flap with a posteriorly located pedicle may be rotated downward beneath the usual vestibular mucoperiosteal flap and the fistulae may be closed. Its use was first described by Abello, Apumoa, Boateng and Mela.

Advantages
  1. This reconstructs bone with bone and mucosa with mucosa.
  2. Reduces the failure rate of repair.
  3. Reduces the post-operative alveolar bone and vestibular atrophy.
  4. Results in osseous closure of fistula.
Disadvantages

This is a prolonged procedure.

Technique

After the vestibular mucoperiosteal flap has been raised to the tooth apices, the periosteum is cut horizontally to permit further flap elevation. The dissection proceeds superiorly to expose the lateral wall of the maxillary sinus covered with periosteum. The area is localised to make an operculum and the periosteum is incised in a U shape with the arms directed posteriorly and diverging to widen the base of the flap. With a fine bur the bony wall of the sinus is cut superiorly, anteriorly and inferiorly. The bony flap is then levered with a periosteal elevator and remaining posterior one fourth of its circumference is fractured. The periosteal pedicle is gently elevated from the maxillary surface posteriorly and the bony flap is brought down to the level of alveolar process to cover the fistula. The bone flap is shaped with rounger to the dimension of the fistula and sutured. The vestibular mucoperiosteal flap is then sutured.

GRAFTS

Various grafts autogenous and alloplasts have been tried along with local or distant flaps for closure of oroantral fistula.

Bone grafts

The use of autogenous bone grafts has been recommended by some authors as an aid in the closure of oroantral fistula. The antral surface of the graft is covered by means of gingival tissue from the adjacent site to the fistula and the oral surface is covered by means of buccal, palatal or tongue flaps. Vuillemin et al have advocated the use of buccal fat pad along with bone grafts for isolating bone grafts from the sinus and the oral mucosa in case of large defects. The use of bone grafts provides rigid contour for support to prosthesis.

Alloplastic materials

A variety of alloplastic and allogenic materialhave been used to close oroantral fistulae. The alloplastic material used include

  • Gold foil
  • Tantulum
  • Gold plate
  • Polymethacrylate
  • Hydroxyapatite blocks
  • Fibrin glue
Gold Foil technique

This has been popularised in the USA by Crolius 1956 and Meyerhoff et al 1973. It is a conservative measure.

  • It requires minimal surgical procedure.
  • It can be done under local anaesthesia.
  • It preserves the full depth of the sulcus.
Uses
  • It is primarily advocated for the management of very large fistulae.
  • In cases of failed flaps from local or other sites.
  • As an immediate simple trouble free protection of the sinus.

This procedure has to be considered only in cases of healthy maxillary sinus.

Procedure

The fistulous tract is excised or curreted to take away the epithelium lining and bringing the underlying defect into view where any diseased bone is removed. A linear incision is made on the crest of alveolar ridge which is extended 1.5cm anteriorly and posteriorly to the defect. The mucoperiosteum is raised exposing about 5mm of bone surrounding the defect.

A small oblong piece of gold foil 24carat of 35gauge is placed over the defect and surrounding bone. It should have a overlap of 3mm that can be tucked under the mucosal wound to prevent dislodgement. The incision is then closed with interrupted sutures. No attempt is made to appose the tissues but leaving an elliptical defect which will expose the gold foil through out the healing period. Granulation tissue grows from around the wound edges on the superior antral surface of the inert gold foil and crosses it to form a bridge. This is said to be complete in most patients in 3-6 months.

The sutures are removed after 10 days. As healing progresses the edges of the oral wound recedes progressively to expose the gold foil which in time can be removed with little difficulty. The oral surface then gradually epithelises.

Disadvantages

The healing above the gold foil cannot be seen and conventional repair may be needed later.

Originally Tantulum plate was used instead of gold foil, while some prefer silastic, Teflon sheet, but gold seems easy to handle.

Stajcic et al described the use of fibrin glue to close small oroantral communications that were recognised at the time of extraction. Here the material is injected into the socket from its depth.

Supportive measures

During the initial healing period, the patients must be advised to avoid movements which stretch the cheek or more blowing activities or forceful mouth rinsing which produces difference between the two sides of the wound.

These patients are put on a course of antibiotics like amoxycillin 500mg 8th hourly to prevent infection.

Patient is advised to do steam inhalation with benzoin or menthol 6th hourly for this moistens the airway and facilitates serous secretion and clears the sinus.

In cases of chronic sinusitis an intranasal antrostomy may be done along with OAF closure to provide drainage to maxillary sinus or it might be combined with a Caldwell-Luc procedure to clear the sinus lining with antrostomy. A simple method for establishing an intranasal antrostomy is to pass heavy curved artery forceps into the floor and laterally into the antrum below the inferior turbinate. A length of ½ inch ribbon gauze can be inserted into the antrum and pulled back to create a smooth margined defect in the medial antral wall. A tubular drain is placed for 24 hours.


Conclusion

Perforation of the maxillary sinus during dentoalveolar surgery is relatively common occurrence. Most of these communications close spontaneously if the sinus is healthy. However, the presence of pre-existing sinus, infection or introduction of a foreign body through the opening can lead to the formation of an Oroantral fistula. The successful management of such cases depends on elimination of infection, removal of the foreign body when present and closure of the fistula with a well vascularised flap that is not under tension and that places suture line on solid bone. There are many procedures, which fulfil these criteria and it would be better to choose simplest method that suits the clinical condition.


REFERENCES

  1. Killey & Kay – outline of oral surgery. Part I
  2. Gustav Kruger – Textbook of Oral & Maxillofacial Surgery.
  3. Moore – Surgery of the mouth and Jaws.
  4. Daniel M. Laskin – Management of Oroantral Fistula and other sinus related complications. Oral & Maxillofacial clinics of North America.1:11:Feb1999.
  5. Roberto Brusati – Use of an Osteoperiosteal flap to close oroantral fistulas. J. Oral & Maxillofacial Surgery, April 1982.
  6. Samman, H. Tidemann – the buccal fat pad in oral reconstruction. International J. Oral & Maxillofacial Surgery. 1992.
  7. Timothy S Thomas – Closure of palatal defect using dorsal pedicle tongue flap. J. Oral & Maxillofacial Surgery, Oct 1982.

 

 

 

 

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Author:

I am a practicing maxillofacial surgeon working in India.

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