Extraoral drilling for zygoma

implant

presentation of two casesLuc@Vrielinck.be

Genk, Belgium

Rationale for modification of the

zygoma implant drilling technique

• The patient presented with a combination of:

– Hemimaxillectomy situation

– Reduced bone volume in the regio of the zygomatic bone

– Limited mouth opening

• When drilling from intraorally it is very easy to miss the

remaining bone volume in the zygomatic bone

• When drilling from extraorally, the bone volume can be

evaluated under direct vision

• It appears to be easier to assure that the implant will be

in as much remaining bone as possible

Indications of the extraoral

drilling technique• Limited mouth opening

• Reduced bone volume in zygomatic bone

• When the implant needs to be anchored in

the lateral orbital rim eventually crossing

the orbital floor

Case 1

• Extraoral drilling for zygomatic implant due to :

– Limited bone volume

– Limited mouth opening

Situation

• Situation after right hemimaxillectomy and

broad irradiation of maxilla and skull base

2005

• Tumor free

• Loss of a zygoma implant right

• Severely limited mouth opening 1 cm

• Postradiotherapy fibrosis and retraction of

the upper lip and cheek

Preoperative view

Loss of right zygoma implant

On the left side: 3 long implants (2 in zygoma, one in pterygoid)

Pterygoid Zygoma

Huge unsupported cantilever !

Loss of right zygoma implant

On the left side: 3 long implants (2 in zygoma, one in pterygoid)

Pterygoid zygoma

Preoperatieve view

Preoperatieve view

Preoperatieve view

Extraoral drilling procedure for

zygoma implant • Determine the correct drilling direction by

drawing a line on the zygomatic bone surface

• Initial drilling with round drill

• Drilling with drills for standard implants

– Ø 1.5 mm, Ø 2 mm, Ø 3 mm

– Followed by zygoma twist drill 3.9 mm

– No drilling with thick zygoma drill to ensure enough

primary stability in the zygomatic bone when inserting

the zygoma implants

• Zygoma implant is inserted intraorally

Note the reduced amount of available bone in the zygomatic region

due to previous resection

Intended drilling direction

Instrument protecting dorsal

surface of zygomatic boneOrbital floor

Drilling with zygoma twist drill Measuring gauge

Protecting the skin surface

Intraoral insertion of the zygoma implant

Final position of the implant

Final view of the implant in place and wound closure

Intraoral view of the new implant in place

Postoperative radiography

Postoperative radiography

Postoperative radiography

Note the very cranial position of the newly placed implant

Case 2

• Situation after reight maxillectomy for

adenoid cystic carcinoma

• No radiotherapy

• Very limited bone volume due to resection

of large part of zygomatic bone

• Planning:

– 1 implant in zygomatic bone

– 1 implant in lateral orbital rim partially

crossing the orbital floor

The appearance of the patient is very well reconstructed using a obturator prothesis

However te the retention of the prosthesis is problematic

The appearance of the patient is very well reconstructed using a obturator prothesis

However te the retention of the prosthesis is problematic

03/09/2011: Intake

03/09/2011: Intake

3D Treatment planning

3D Implant planning

3D Implant planning

3D Implant planning

3D Implant planning

3D Implant planning

3D Implant planning

Exposed outer surface of zygomatic bone with initial drilling

Perforating tip of the zygoma

Implant is removed with round drill

Actual length needed was 25 mm, shortest available zygoma implant is 30 mm

Postoperative radiography

Postoperative radiography

Postoperative radiography

Postoperative radiography