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78 Prospective 5 year outcome of custom made total TMJ replacement
Oral presentations / British Journal of Oral and Maxillofacial Surgery 48 (2010) S1–S24
specificity 0.45 & 1.00 and 0.42 & 0.93 respectively). TMF gave no statistically significant difference between benign and malignant tumours. Conclusions and Clinical relevance: Our analysis confirms p16 promoter hypermethylation in malignant progression of PA to CXPA. In addition methylation across several gene promoters gives weight to the development of a diagnostic biomarker for malignant progression. As genomic analysis becomes the routine, promoter methylation may offer a diagnostic biomarker for malignant progression superior to present cytological assessment. 78 Prospective 5 year outcome of custom made total TMJ replacement A. Sidebottom. Queens Medical Centre, Nottingham University NHS Trust, UK The TMJ Concepts is a custom-made prosthesis with titanium body and cobalt-chrome condylar head on high molecular weight polyethylene fossa articulating surfaces. This prosthesis has outcomes up to 17 years and is currently the favoured prosthesis in the UK. This review analyses the outcome of the authors first 5 years of cases using this prosthesis. Results: Indications: 43 patients (64 joints), 36 left, 28 right • age 27–70 (mean 47) • main diagnoses – degenerative disease 11 – rheumatoid 6 – post-trauma 9 – post multiple surgery 6 – ankylosis 6 – psoriatic 3 • revision cases 11 Pain (10 cm analogue): • pre-op 83 (45–100) • 6/52 post-op 28 (0–69) • 6/12 post-op 17 (0–70) • 1 year post-op 9 (0–60) [47 joints] All patients improved. Opening (mm): • Pre-op 24 (3–44) mm • 6/52 post-op [42 patients] 27 (15–41) mm • 6 months [35 patients] 31 (15–43) mm • 1 year post-op [31 patients] 32 (15–45) mm All patients with reduced opening showed improvement. Dietary scores (10 cm analogue liquid to solid): • Pre-op 41 (1–100) • Post-op 1 year 93 (25–100) All patients improved. Revisions: Case 1. Acute dental infection 3 days post-op. Dentist delayed treatment for 6 weeks. Biofilm infection of the prosthesis required joint removal and placement of gentamicin impregnated acrylic spacer for 3 months. Now 3 years post revision prosthesis with no ongoing problems. Case 2. 6 weeks post-op developed otitis externa with secondary cellulitis of face and secondary joint infection. Joint removed, awaiting replacement. Conclusion: TMJ replacement provides an excellent mode of reconstruction of the irreparably damaged TMJ.
S21
79 Evaluation of conformity between clinical and pathological TNM staging for oral and oropharyngeal squamous cell cancer S. Anderson, J. Zhao, J. Ubhi, V. Bhatt, K. Webster. University Hospital Birmingham, UK Background: Clinical staging of oral and oropharyngeal squamous cell cancer using the TNM staging system can be difficult to ascertain accurately with current methods, particularly nodal involvement. Imaging assisted clinical staging is perhaps more accurate and informs the clinician of locoregional and distant metastases. Conformity of clinical TNM stage (cTNM) to pathgological TNM stage (pTNM) is an indicator of accurate assessment and provides a basis for prognostication. Underestimation of staging clinically may lead to lesser treatment and overestimation conversely leads to aggressive treatment where not required. Patients and Methods: In this retrospective study we looked at the clinical and pathological TNM staging of all operated cases of oral and oropharyngeal squamous cell cancer between 1st January 2008 and 31st December 2009 from case records, online pathology reports imaging reports and documentation on the Somerset Cancer Database within our Unit. Results: The principal manifestation of the staging inconsistency was that the pTNM stage was more advanced than cTNM stage in upto 15% of cases. The principal influencing cause was that N stage was not well evaluated by cTNM. In very few cases there was downstaging of T stage on pathological examination. Conclusion: Current clinical methods of evaluating cTNM stage are not accurate. pTNM staging is generally considered more accurate where nodal status is concerned. There is room for error in the reporting of the pathological T stage. 80 Initial evaluation of a novel total TMJ replacement E.W. Abel, P. McLoughlin, F. Stewart, S. Huang. University of Dundee, UK Introduction and Aims: A new custom made total TMJ replacement has been designed in Dundee. The prosthesis is metal on metal and the design concept allows a minimalist design. The only bone removal is the diseased condylar bone. The remaining condylar head and neck provide structural support for the prosthesis, allowing a small mandibular ramus plate to be used, secured with only four screws. As part of the design and development process, the prosthesis is being subjected to an engineering analysis, in order to assess the structure for stresses under loading and to consider, if necessary, design changes to the device. Material and Methods: A computer based stress analysis using finite element analysis. The prostheses are fabricated in the Department of OMFS, Dundee, from which a 3D scan of a typical prosthesis was used for the computer model. The model was tested under simulated physiological loading conditions for strength in the main structure and at the points of screw fixation. An initial study of the contact stresses at the articulating surfaces was also undertaken. Results: The stresses were in all cases well below the failure stress of the cobalt chrome material. Even with a loss of bone-prosthesis contact at the interface between the resected condylar head and the prosthesis, the local stresses did not exceed 10% under normal loading conditions. There were similarly low levels of stress in the screw hole regions.
specificity 0.45 & 1.00 and 0.42 & 0.93 respectively). TMF gave no statistically significant difference between benign and malignant tumours. Conclusions and Clinical relevance: Our analysis confirms p16 promoter hypermethylation in malignant progression of PA to CXPA. In addition methylation across several gene promoters gives weight to the development of a diagnostic biomarker for malignant progression. As genomic analysis becomes the routine, promoter methylation may offer a diagnostic biomarker for malignant progression superior to present cytological assessment. 78 Prospective 5 year outcome of custom made total TMJ replacement A. Sidebottom. Queens Medical Centre, Nottingham University NHS Trust, UK The TMJ Concepts is a custom-made prosthesis with titanium body and cobalt-chrome condylar head on high molecular weight polyethylene fossa articulating surfaces. This prosthesis has outcomes up to 17 years and is currently the favoured prosthesis in the UK. This review analyses the outcome of the authors first 5 years of cases using this prosthesis. Results: Indications: 43 patients (64 joints), 36 left, 28 right • age 27–70 (mean 47) • main diagnoses – degenerative disease 11 – rheumatoid 6 – post-trauma 9 – post multiple surgery 6 – ankylosis 6 – psoriatic 3 • revision cases 11 Pain (10 cm analogue): • pre-op 83 (45–100) • 6/52 post-op 28 (0–69) • 6/12 post-op 17 (0–70) • 1 year post-op 9 (0–60) [47 joints] All patients improved. Opening (mm): • Pre-op 24 (3–44) mm • 6/52 post-op [42 patients] 27 (15–41) mm • 6 months [35 patients] 31 (15–43) mm • 1 year post-op [31 patients] 32 (15–45) mm All patients with reduced opening showed improvement. Dietary scores (10 cm analogue liquid to solid): • Pre-op 41 (1–100) • Post-op 1 year 93 (25–100) All patients improved. Revisions: Case 1. Acute dental infection 3 days post-op. Dentist delayed treatment for 6 weeks. Biofilm infection of the prosthesis required joint removal and placement of gentamicin impregnated acrylic spacer for 3 months. Now 3 years post revision prosthesis with no ongoing problems. Case 2. 6 weeks post-op developed otitis externa with secondary cellulitis of face and secondary joint infection. Joint removed, awaiting replacement. Conclusion: TMJ replacement provides an excellent mode of reconstruction of the irreparably damaged TMJ.
S21
79 Evaluation of conformity between clinical and pathological TNM staging for oral and oropharyngeal squamous cell cancer S. Anderson, J. Zhao, J. Ubhi, V. Bhatt, K. Webster. University Hospital Birmingham, UK Background: Clinical staging of oral and oropharyngeal squamous cell cancer using the TNM staging system can be difficult to ascertain accurately with current methods, particularly nodal involvement. Imaging assisted clinical staging is perhaps more accurate and informs the clinician of locoregional and distant metastases. Conformity of clinical TNM stage (cTNM) to pathgological TNM stage (pTNM) is an indicator of accurate assessment and provides a basis for prognostication. Underestimation of staging clinically may lead to lesser treatment and overestimation conversely leads to aggressive treatment where not required. Patients and Methods: In this retrospective study we looked at the clinical and pathological TNM staging of all operated cases of oral and oropharyngeal squamous cell cancer between 1st January 2008 and 31st December 2009 from case records, online pathology reports imaging reports and documentation on the Somerset Cancer Database within our Unit. Results: The principal manifestation of the staging inconsistency was that the pTNM stage was more advanced than cTNM stage in upto 15% of cases. The principal influencing cause was that N stage was not well evaluated by cTNM. In very few cases there was downstaging of T stage on pathological examination. Conclusion: Current clinical methods of evaluating cTNM stage are not accurate. pTNM staging is generally considered more accurate where nodal status is concerned. There is room for error in the reporting of the pathological T stage. 80 Initial evaluation of a novel total TMJ replacement E.W. Abel, P. McLoughlin, F. Stewart, S. Huang. University of Dundee, UK Introduction and Aims: A new custom made total TMJ replacement has been designed in Dundee. The prosthesis is metal on metal and the design concept allows a minimalist design. The only bone removal is the diseased condylar bone. The remaining condylar head and neck provide structural support for the prosthesis, allowing a small mandibular ramus plate to be used, secured with only four screws. As part of the design and development process, the prosthesis is being subjected to an engineering analysis, in order to assess the structure for stresses under loading and to consider, if necessary, design changes to the device. Material and Methods: A computer based stress analysis using finite element analysis. The prostheses are fabricated in the Department of OMFS, Dundee, from which a 3D scan of a typical prosthesis was used for the computer model. The model was tested under simulated physiological loading conditions for strength in the main structure and at the points of screw fixation. An initial study of the contact stresses at the articulating surfaces was also undertaken. Results: The stresses were in all cases well below the failure stress of the cobalt chrome material. Even with a loss of bone-prosthesis contact at the interface between the resected condylar head and the prosthesis, the local stresses did not exceed 10% under normal loading conditions. There were similarly low levels of stress in the screw hole regions.