Extraoral drilling for zygoma implants

Extraoral drilling for zygoma implant presentation of two cases Luc@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

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

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

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 Orbital floor

Instrument protecting dorsal surface of zygomatic bone

Drilling with zygoma twist drill

Protecting the skin surface

Measuring gauge

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

Note the very cranial position of the newly placed implant

Postoperative radiography

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