BY :DR. NIKIL JAIN KIIT UNIVERSITY

Maxillary Osteotomy Procedures

Introduction

Dentofacial deformities affect 20%of the population.Orthognathic surgery is a team work.

This team must Correctly diagnose existing deformities Establish an appropriate treatment plan Execute recommended treatment.

Basic theraputic goals Function Aesthetics Stability Minimizing the treatment time.

History

In 1859 by Von Langenbeck -- for the removal of nasopharyngeal polyps.

The first American report -- Cheever in 1867 -- for the treatment of complete nasal obstruction secondary to recurrent epistaxis for which a right hemimaxillary downfracture was used.

In 1927 Wassmund -- LeFort I osteotomy for the correction of the midfacial deformities and used orthopedic force postsurgically

In 1934 Axhausen described total mobilization of the maxilla with immediate repositioning for an open bite case

In 1942 Schuchardt first advocated the pterygomaxillary dysjunction.

In 1949 Moore and Ward -- horizontal transaction of the pterygoid plates for advancement

In 1965 Obwegeser -- complete mobilization of the maxilla so that repositioning could be accomplished without tension.

Bone grafting to enhance stabilization for LeFort and anterior osteotomies -- by Cupar, Gilles and Rowe and Obwegeser.

Early description of the rigid fixation of maxillary osteotomies were published by Michelet and colleagues in 1973, Horster in 1980, Drommer and Luhr in 1981, and Luyk and Ward-Booth in 1985.

SEQUENCE OF TREATMENT PLANNING

1} Dental and periodontal treatment

2} Extractions

3} Presurgical orthodontics Position teeth over their respective basal bone Align and level the teeth Adjust for tooth size discrepancies Connect related teeth Divergence of roots adjacent to surgical sites.

4} Orthognathic surgery

5} Post-surgical orthodontics Final tooth alignment and root parallelism Maximal interdigitation Ideal over bite and overjet Centric occlusion - centric relation

Various Maxillary Osteotomies Segmental maxillary surgeriesi. Single tooth dento-osseous osteotomies.ii. Corticotomyiii. Anterior segmental maxillary osteotomy iv.Posterior segmental maxillary osteotomy v.Horse shoe osteotomy.

Total maxillary osteotomies:I) Le Fort I osteotomiesII) Le Fort II osteotomiesIII) Le Fort III osteotomies

Surgicaly assisted maxillary expansion

Quadraangular lefort I and lefort II osteotomy

High level midface osteotomy

Surgical anatomy of maxilla

Osseous structuresMaxillary sinusInfraorbital rimAnterior nasal spinePalateMaxillary tuberosityPyramidal process of

palatine bonePterygomaxillary

junction

Vascularization

Pathway of the Ascending palatine,Ascending pharyngeal, and Descendingpalatine arteries as they continue into the greater palatine arteries.

Reference Marks, and IntraoperativePositioning

At surgery, slots are madein the piriform rim and holes in the buttress to simulate points A and P bilaterally. The gingival cuffs of the canines and first molars represent points B and C.

Following mobilization of the maxilla it is placed so that the differences between lines A–B and A–B' are the same as they were on the models.

Biological basis of maxillary osteotomy

Revascularization studies of bell and fonseca indicates that’ the maxilla may be mobilized and repositioned and survival continue as long as mobilized maxilla attached to a broad soft tissue pedicle’ .

Healing occur even if maxilla segmented into several pieces .

Necrosis occurs only when vascular pedicles are damaged

Mucoperiosteal arterial system –cortical bone- supply maxilla Vascular connections- arteries and veins

The multiple sources of blood supply to maxilla and the abundant vascular communications between the hard and soft tissues constitute the biologic foundations for maintaining dento-osseous viability despite transcetion of medullary blood supply after osteotomies

The soft tissue of the palate ,lateral pharyngeal walls and buccal mucosa provide the vascular network that permits the healing.

The rich ,freely anastomosing vasculature of the face is responsible for this healing

Loss of bony segments due to vascular ischemia is result of poor surgical technique or violation of basic biological principles.

Poor incision design ,extensive detachment of palatal mucoperiosteum, excessive pressure by splint, excessive and continue manipulation of surgical site, traumatic manipulation of maxilla during down fracture also associated with post operative complications.

Blood flow in gingival tissue after osteotomy

Soft palatal, ascending pharyngeal, and ascending palatal vessels anastomose with the greater palatine artery. Major vessels have beensectioned and tied. The arrows signify direction of blood flow.

Bell et.al (1970s) – early osseous union and minimal osteonecrosis

You et.al (1991) -- no histologic evidence of osteonecrosis

Siebert et.al (1997) – ascending palatine and pharyngeal artery major contribution to palatal blood supply

In segmental maxillary osteotomy the blood supply is via the buccal and palatal mucoperiosteum and the intraalveolar vessels

Technique to preserve the vascular supply

Horizontal incision ,through buccolabial mucoperiosteum above the level of keratinized gingiva or attached gingiva margin at the level of maxillary teeth apices,extending from first molar one side to first molar contralateral side

The superior tissues are reflected subperiosteally, first at the piriform aperture margins . Progressively more superior exposure lateral to the nasal aperture will expose the infraorbital nerve exiting from its foramen.

Posterior reflection proceeding from the delineated infraorbital foramen reveals the zygomaticomaxillary suture, zygomatic buttress, and the most anterior aspect of the zygomatic arch.

Inferiorly, with subperiosteal tunneling, the lateral aspect of the maxillary tuberosity and its junction with palatine bone and pterygoid plates of the sphenoid bone are identified

The nasal mucosa is elevated beginning on the superolateral surface of the piriform rim.

Curved Freer elevator used for this dissection,angles inward and downward,keeping in mind that nasal cavity is greater in volume interiorly than at the piriform apprature

Dissection carried out up to 15 to 20 mm The mucoperiosteum is reflected from the nasal floor,

lateral nasal wall, and nasal crest of the maxilla.

The dissection should continue superiorly for a centimeter up the vertical nasal walls to prevent tearing during osteotomy or down-fracture of the maxilla, particularly at the superior reflections of the nasal floor medially and laterally

Osteotomy

Obtaining appropriate access to maxillary segment ,apices of root identified by the bony protuberance or by using peria apical or panoramic radiographs

Osteotomy kept 5-6 mm apical to apical to roots of maxillary teeth, it means 30- 35 mm from the tip of the crown

During osteotomy lateral nasal wall,great attension to protect nasal mucosa medially, so osteotomy terminated after 20 mmto avoid injury to descending palatine artery.

1. Pterygomaxillary dysjunction- Obwegeser osteotome to separate the maxillary tuberosity and pterygoid plates, as previously described by ROBINSON & HENDY

The osteotome was positioned parallel

to the occlusal plane

Relationship between maxillary artery & maxillary osteotomies

• Turvey & Fonseca (J.Oral Surg. 1980; 38: 92-95)

16 cadavers/32 sidesMeasured distance from inf. pterygomax.

junc. to max. artery Mean distance25mm (range 23-28mm) Mean height of pterygomax junc. 14.6mm

(range 11-18mm) Width of pterygoid chisel 10-15mm

Curved pterygomaxillary osteotome was used except that the pterygomaxillary dysjunction was achieved through the maxillary tuberosity itself, rather than between the maxillary tuberosity and the pterygoid plates, by the technique advocated by TRIMBLE,STOELINGA JOMS VOL 41 ISSUE 8 1983,544-546

No incision was made and the osteotome was placed on the tuberosity, distal to the second molar, and approximately 0.5-1.0 cm above the crest of the tuberosity. Better visibility and easier access were achieved by this approach than by attempting to position the osteotome through the tunnel created under the posterior buccal soft-tissue pedicle

Care must be taken to angulate the osteotome properly, so that it does not penetrate too far anteriorly; this could cause a separation at the junction of the horizontal process of the palatine bones and the palatal process of the maxilla, or create a fracture through the greater palatine foramen which could damage the descending palatine artery.

Surgically Assisted Maxillary Expansion

Assists to correct deformities in transverse dimension.

First described by Angell in 1860

This procedure is in essence combination of distraction osteogenisis and controlled soft tissue expansion.

Diagnosis and clinical evaluation: paranasal hallowing narrowed alar base deepening of nasolabial folds zygomatic difficiancy

Treatment options: Based on skeletal maturity

Slow dentoalveolar expansion Orthopedic rapid maxillary expansion SAME Segmental maxillary osteotomy

Advantages of SAME improved stability non extraction alignment of

dentition elimination of negative space improved periodontal health and

nasal respiration

Indications: skeletal discrepancy greater than 5mm

assossiated with wide mandible failed orthodontic expansion extremely thin, delicate gingival tissue significant nasal stenosis.

Technique: First the mandibular dentition should be

decompensated Expansion appliance should be placed

preoperatively

Steps:Bilateral osteotomy from pyriform rim to

pterygomaxillary fissure Release of nasal septum Midline palatal osteotomy Osteotomy of the anterior 1.5mm lateral

nasal wallBilateral release of pterygoid platesActivation of appliance by 1 to 1.5mmSoft tissue closure

S A M E-PROCEDURE

APPLIANCE IN PLACE

Maxilla should remain stationary for 5 days postoperatively.

Pt should feel discomfort while activation.Expansion at a rate of 0.5 mm/dayOver correction is not recommended.Retention: 6 to 12 months after expansion

Modified SAME

Unilateral or asymmetric deformities

Osteotomy done on one side

Non operated site buccal bone bending and dental tipping

Relapse occure non operated site

Six month for midpalatal healing

Complications:a)Those due to inadequate surgery:

pain dental tipping

periodontal breakdown post orthodontic relapseb)Those due to expansion lack of appliance expansion deformation of the appliance due to

processing errors stripping or loosening of midpalatal

screw

Segmental Osteotomies

Single tooth osteotomy:

Indicated in tooth mal position.

Dental ankylosis.

closure of diastema.

Two vertical cuts,1-2mm either side of proposed bony cut.

Mucoperiosteum not elevated over the tooth.

Labial bone scored. Horizontal cut is made

3mm above the apex.( when nasal floor is

relatively low, cuts may be extended into it )

Advantages: Reduction in the treatment time. Lower incidance of relapse.

Disadvantages: Injury to teeth Periodontal compromise Devitalization of teeth

Corticotomy

Cortical bone remove both labialy and palatally

Supra apical region , 5mm above the apices of teeth

palatal bone is removed in radial fashion, taking out the cortex in wide strips between each tooth

Repositioning of teeth with in arch obtained in 6-12 weeks

Anterior maxillary osteotomy

Cohn Stock 1921- first report

Indications: Bimaxillary protrusion Protruded maxillary teeth with normal

inclination to alveolar bone. Anterior open bite. When orthodontic teeth movement not

possible. To reduce the prominence of the upper lip.

Wassmund technique(1935)

Preserves both buccal and palatal pedicle.

Buccal as well as anterior verticle incision

Tunneling between anterior and buccal incisions

Trans palatal osteotomy through buccal vertical osteotomy.

Occasional mid palatal sagittal incision.

Wunderer method(1963)

Relies on intact buccal pedicle.

Transpalatal incision combined with buccal verticle incision.

Modification: Midline vertical

incision combined with buccal vertical incision.

Cupar method Buccal vestibular

incision

Nasal septum is first released

Horizontal osteotomy followed by vertical buccal osteotomy.

Trans palatal osteotomy under direct vision.

Advantages: Direct access to the nasal structures and

superior maxilla Preservation of the palatal pedicle Ease of placement of rigid fixation Ability to remove bone from palate.

Complications of the AMO:Loss of teeth vitality.Persistant periodontal defectsCommunication with nasal cavity or antrumOcclusal steps formation.

Posterior maxillary osteotomy

Schuchardt 1959 first report

Indications: Posterior maxillary hyperplasia. Distal repositioning of the posterior

segment. Posterior open bite. Transverse excess or deficiancy Spacing in the dentition.

Surgical technique: Buccal vestibular incision below the

buttress. Platal osteotomy through the buccal

osteotomy site. Occasional palatal incision. Principles are same as for the total

maxillary osteotomies.

Complications: Same as that for other osteotomies. Blind procedure. Technically challenging

POSTERIOR SEGMENTAL OSTEOTOMY

PTERYGO MAXILLARY DISJUNCTION

Summary: Segmental osteotomies are indicated for

isolated dento facial deformities when there is good dento skeletal relationships in the non affected areas.

Decreased morbidity when compared to total maxillary osteotomies.

For isolated dentofacial deformities and prosthetic problems, the segmental osteotomies should be in the armamentarium of the surgeon.

Lefort I Line

Line runs horizontally above the floor of nasal cavity, involves the lower third of septum ,palate ,alveolar proces sof maxilla and lower third of pterygoid plates of sphenoid

Le-Fort 1 osteotomy

Work horse of the orthognathic surgical procedures.

Broad application to resolve many functional and aesthetic problems.

Biologic basis: Rich anastamosing vasculature of the face. Maxilla is clothed by wide soft tissue. Osteotomised segment should remain

attached to soft tissue pedicle.

Indications

Vertical maxillary excess in bimax protrusion.

Superior re positioning of the maxilla to correct open bites.

To advance maxilla in cleft palate and post traumatic patients.

To correct open bites when combined with mandibular procedures.

Correction of cants.Advancement of the maxilla in class III

patients.

Surgical technique

Patient position: head end elevation by 10degree.

Reference pins should be placed when vertical changes are planned.

Incision: Maxillary vestibular incision high in the muco buccal fold.

Incision traverses the mucosa, muscles and the periosteum.

LE FORT I OSTEOTOMY

Sub periosteal dissection.

Infra orbital nerve identified and preserved

Nasal mucosa dissected from nasal wall and floor.

Dissection in buttress region kept inferiorly.

Vertical reference points placed in pyriform aperture and buttress.

VESTIBULAR INCISION

OSTEOTOMY MARKINGS

Osteotomy should be kept below the pyriform aperture region.

Initial cuts in the buttress region progressing towards the nose.

Next the posterior cuts in the pterygo maxillary region kept inferiorly.

Minimum of 5mm above the root apices.The next cut in the sinus from inside out.Same procedure for the opposite side.

POSTERIOR CUTS

SINUS CUTS USING RECIPROCATING SAW

SEPTAL OSTEOTOMY

LATERAL NASAL OSTEOTOMY

SEPTAL CLEARANCE

Septal cartilage and the septum freed from the maxilla.

Lateral nasal cut is then performed all the way till perpendicular plate of palatine bone.

Final step is seperation of maxilla from pterygoid plate.

Care should be taken to preserve the descending palatine vessels.

PTERYGO MAXILLARY DISJUNCTION

In case of superior repositioning of the maxilla sufficient bone and cartilage should be removed from the septum.

Mobilization of the maxilla is done.Occlusal splint b/n maxilla and mandible is

then fixed.Maxillo mandibular complex is rotated

supporting the condyles in the fossa.

CONDYLAR REPOSITIONING

Correct vertical re positioning is ensured using reference pins.

Stabilization: Small bone plates (1.5mm) or intra osseous

wiring applied at pyriform aperture and buttress region.

WIRE FIXATION

PLATE FIXATION

Segmenting the maxilla:Indications: Transverse discrepancies between the dental

arches Vertical steps in the maxillary occlusal plane Space remaining in the maxillary arch.

Two para median osteotomies and one transverse osteotomy are used.

Midline sectioning of the palate is avoided.Osteotomised segments should never be

stripped off the nourishing mucosa.

SEGMENTING THE MAXILLA

Bone grafts: Indicated when large defects in the walls of

maxilla are present. Critical in buttress and lateral walls.Advantages: Greater stabilization promote healing and Consolidation of the osteotomy sites.

Autogenous bone grafts preferred Cranial bone, iliac crest and sometimes

mandibular buccal cortex.

BONE GRAFTING

Wound closure: Done in layers Periosteum and muscle layer closed first in

buttress and nasal base. Mucosa of the lip closed with a horizontal

mattress suture in v-y pattern. This helps to maintain the height of the

exposed vermilion and lip length.

V-Y CLOSURE

Alar sinch Suture

MODIFIED LE FORT I OSTEOTOMIES

Quadrangular osteotomy - (Kufner 1971)

This technical note should be kept in mind whenever an anterior and downward movement is planned and vertical stability might be compromised.

LE FORT II OSTEOTOMY (HENDERSON AND JACKSON, 1973

Indications Naso-maxillary hypoplasia, such as Binder syndrome

Retruded naso-maxillary complex resulting from mal or non treated Le Fort II fracture

Cleft lip and palate deformity

INCISIONS

Nasal root and medial orbital wall approached by a coronal incision or paranasal incision or medial brow incision

Coronal incision runs from upper anterior attachment of helix over the cranial vault passing behind the hair line

Dissection carried forward in loose connective tissue plane deep to galea Incision to pericranium 3 cm posterior to supraorbital rim to expose

supraorbital rim and orbit Conjunctival or subciliary incision is required to gain access to

infraorbital rim and orbital floor Subperiosteal dissection through subciliary incision should join the

dissection above to enable bone cut under direct vision Access to canine fossa and posterior maxilla by routine buccal vestibular

incision

OSTEOTOMIES

Horizontal cut over nasal bridge passing below the anterior ethmoidal foramen

Vertical cut is continued by a cut in the orbital floor medial to the exit of infraorbital nerve

Bony nasal septum is split at nasal bridge by a forked septum chisel Posterior separation by pterygomaxillary dysjunction

Bone cut around zygomatic buttress downward and posteriorly

A Sagittal cut by thin fissure bur passing behind the lacrimal sac to the orbital floor

Repositioning of maxillaFixation

MODIFIED LE FORT II OSTEOTOMY

Psillakis, Lapa and Spina (1973) designed modified Le fort II, which leaves tooth bearing area behind

LE FORT III OSTEOTOMY(GILLIES, 1940)

INDICATIONS Naso-maxillary hypoplasia along with

underdevelopment of malar bone A retruded midface due to trauma Pseudo-exophthalmos as a result of shallow

orbit Mild hypertelorism and telecanthus

Incision

Orbit and nasal root is approached by coronal incision

Subperiosteal dissection from FZ suture to expose lateral orbital wall

Periosteum is split vertically at nasal root and malar area to accommodate

anticipated advancement

Orbital floor is approached by separate conjunctival or subciliary incision

Buccal vestibular incision to complete osteotomy in posterior maxillary

area

Osteotomy

Ostoetomy starts at lateral orbital wall by reciprocal saw extending to the

inferior orbital fissure

Cut extended through orbital floor crossing the pathway of infraorbital

nerve

Bone cut at nasal bridge links up with osteotomy in the floor behind

lacrimal duct

Osteotomy in lateral orbital wall carried downward tangentially through

zygomatic bone passing below the buttress

Posterior separation by pterygomaxillary dysjunction

Complications

1} Relapse:

most commonly with advancements and downgrafts patients with parafunctional habits prevention – rigid fixation grafting control of parafunctional habits

2} Settling:

differs from relapse movement regardless of original position seen with # grafts and wire osteosynthesis prevention – rigid fixation control of parafunctional habits

3} Transverse relapse:

-- common with segmental osteotomies and transverse expansion -- lack of soft tissue mobilization at the time of expansion -- inadequate grafting and stabilization along the palatal midline -- poorly adapted bone plates -- unstable presurgical orthodontic movements -- hyperfunctional buccinator muscle activity

Prevention

-- a bone plate placed across the nasal floor -- a heavy guage circumferential arch wire in the molar head gear bracket tubes -- a transpalatal arch bar to maintain the palatal width -- an occlusal coverage splint -- a palatal splint without occlusal coverage

4} Condylar distraction:

-- occurs when there are interferences in the tuberosity or pterygoid plate area Prevention

-- elimination of bony interferences

5} Bleeding:

-- common areas include – descending palatine vessels and

anterior or posterior palatine vessels; PSA vessels; pterygoid

plexus; incisive canal vessels; internal maxillary artery; vessels

associated with the nasal septum and turbinates.

6} Avascular necrosis: -- initially – gingiva – dusky appearance -- no refill after tissue blanching -- sloughing within 12 to 24 hrs -- exposure of bone/ roots without infection Prevention and management

-- careful flap design and surgery -- HBO therapy – 20 to 30 dives -- conservative debridement and good oral hygiene -- reconstructive procedures if needed

7} Periodontal defects:

-- trauma to adjacent soft tissues and bone -- avascular necrosis -- tearing of interdental soft tissue through the papilla -- removal of the bony collar around the neck of the teeth -- vertical incisions at interdental areas

8} Nerve injury

9} Infection

10} Non-union

Epiphora

Illustration of lateral wall, showing the distance from the anterior attachment of the inferior turbinate to the nasolacrimal canal orifice OLD- ostium of nasolacrimal duct OL- high lefort 1 osteotomy line IT- inferior turbinate MT- medial turbinate

The meatal portion of the nasolacrimal duct can be protected by detaching the mucosa from the lateral nasal wall and placing and elevator between the mucosa and the lateral nasal wall as the osteotomy is accomplished. IT- inferior turbinate MT- medial turbinate

SOFT TISSUE CHANGES

Several investigators have suggested that the etiology of

these soft tissue changes is attributable to three factors

Elevation of the periosteum and muscle attachments

adjacent to nose without adequate replacement

Postsurgical edema

Increased bony support in advancement cases

TECHNIQUES TO CONTROL THE SOFT TISSUES

V-Y CLOSURE

ALAR CINCH

CONTOURING THE ANS

DOUBLE V-Y CLOSURE

Conclusion

Orthognathic surgery has made it possible to reposition of either or both jaws in all possible directions. This has provided solution for the patients with severe dentofacial problems and malocclusion. Thorough evaluation and assessment of the defect and efficient execution of the surgery is needed for effective result.

Repeated assessment and rectification of the technique are required to improve the outcome of these aesthetic surgical procedures.

References

Fonseca – Oral and Maxillofacial Surgery – Vol. 2

Dentofacial Deformities – Bruce N Epker John P Stella, Leward C Fish

Orthognathic Surgery – Varghese ManiPrinciples of oral and maxillofacial surgery –

Peterson Surgery of mouth and jaw – MooreText book of otrhognathic surgery - Reyenke

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