Engineering Assisted Surgery
Precision Osteotomies

Mandibular Reconstruction



Major Craniofacial Injury



History

This patient suffered a major craniofacial injury 30 years ago. Reconstruction of the mandible was carried out using a hip graft, and the chin was reconstructed with a deltopectoral flap.

Presenting Complaint

Severe salivary incontinence prevented a satisfactory quality of life; this was related problems with the hip graft. An SLS biomodel confirmed that the hip graft was :-
  • too short
  • had been placed back to front and upside down - confirmed by :-
  • the area destined to be the chin (C) which was positioned at the back of the jaw
  • the bone graft displayed a bucket handle deformity and had rotated inferiorly around its long axis
  • this bony deformity had lowered the floor of mouth on the left side and :-
  • resulted in abnormal positioning of the facial muscles so that :-
  • lip incompetence resulted (inability to close the lips)
  • the patient wore an upper denture with an obuturator (bung) to close off a hole in the palate
  • he was unable to wear a lower denture
Salivary leakage from the mouth was so severe that a towel had to be worn over the left shoulder in an attempt to control salivary drooling during this 30 year period.

Treatment Plan




Surgery time 1 hour

A precision posterior osteotomy bone cut was planned using a customised cutting jig with a bevelled posterior flange. This permitted accurate angulated bone cuts for removal of a wedge of bone at a precise angle of 8 degrees. Combined with a straight osteotomy bone cut on the anterior flange, this permitted :-
  • mobilisation of the bucket handle deformity
  • elevation of the bucket handle deformity
  • rotation of the bucket handle fragment on its longitudinal axis
  • elevation of the bucket handle fragment and floor of the mouth by 2.5cm
  • elevation of the facial musculature to produce competent lips
  • cessation of salivary incontinence


Dental Rehabilitation

A lower overdenture was constructed at 6 months using the MDI Sendax mini dental implant system http://www.imtec.com



Outcome

This patient has an excellent outcome with transformation of the quality of life. The denture is absolutely stable and normal eating is now possible.

Discussion


This case emphasises the role of Engineering Assisted Surgery™ in the conversion of a major surgical problem into a simple surgical solution. A staged reconstruction was possible without the recourse to a major surgical intervention. This has major implications for the purchasers of healthcare. The author argues that the time has now arrived for a major multidisciplinary reappraisal of this technology.

Acknowledgements

The author wishes to acknowledge the contribution of Peter Pearson of Orthopaedic Innovations, Sheffield whose engineering brilliance made this precision osteotomy possible. The contribution of Dr Victor Sendax, inventor of the MDI Sendax mini implant system was also paramount in achieving the degree of success in this case. The dental laboratory contribution of Mr Ben Swindell of Crown Ceramics Codnor Derbyshire was also invaluable in the manufacture of a superb dental prosthesis.