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Genioplasty
By – Dr. Shalini Singh
PG OMFS
Contents
•Introduction
•Anatomy
•Preoperative evaluation
• Facial analysis
• Cephalometric evaluation
•History of genial p...
Introduction
• Genioplasty is the surgical procedure used to alter the size
and morphology of the bony chin with concomita...
Anatomy
Anatomy
Preoperative Evaluation
• Chin deformitiesChin deformities can manifest incan manifest in three dimensionsthree dimensions...
CEPHALOMETRIC EVALUATION
• Down's,Down's,
Steiner's,Steiner's,
andand
Tweed'sTweed's
analysesanalyses
The bony chin positi...
SOFT TISSUE EVALUATION
• Gonzales-Ulloa andGonzales-Ulloa and
StevensStevens, in which a, in which a
line is constructedli...
Merrifield's "Z" angle
• is a line from the soft tissue chin tangent to the most pro­cumbent lip,is a line from the soft t...
Ricketts aesthetic plane
• a line from the tip of the nose to the chin. He found thata line from the tip of the nose to th...
• HoldawayHoldaway suggested a line tangent to the chin andsuggested a line tangent to the chin and
upper lip. This line f...
• ZimmerZimmer proposed a line from theproposed a line from the anterior nasal spineanterior nasal spine toto
Down's "B" p...
COGS (cephalometric analysis
for orthognathic surgery)
B – Pg (ll MP): This is the
distance from point B to a
line perpend...
N – B (ll HP): This is also
measured in a plane
parallel to HP from point
B to the perpendicular
line dropped from N. This...
• SteinerSteiner also used soft tissue components to define pleasingalso used soft tissue components to define pleasing
pr...
• All cephalometric assessments should be critically weighedAll cephalometric assessments should be critically weighed
aga...
History of Genial
Procedures
• HoferHofer(1942) first described horizontal sliding osteotomy---(1942) first described hori...
CHIN CLASSIFICATION:
• Guyuron, et al. have put forth a system to convey abnormalities with the
chin. it can serve as a us...
Types of genioplasty
•Osseous genioplasty
•Alloplastic genioplasty
Incisions
•Intraoral- labial sulcus incision
•Extraoral...
• Types of osseous genioplasty
• Horizontal osteotomy with advancement
• Horizontal osteotomy with AP reduction
• Tenon te...
Horizontal Osteotomy
with Advancement
Horizontal Osteotomy with
Advancement
Double Sliding Horizontal
Osteotomy
Overlapping Genioplasty
Horizontal Osteotomy with
Anteroposterior Reduction
Tenon Technique---Michelet and
associates 1974.
• The tenon technique allows for mortising of the tenon into the mobilized...
Transverse deformities of chin
• Transverse deficiencyTransverse deficiency
• Transverse excessTransverse excess
• Asymmet...
Widening/narrowing of
chin
Correction of mandibular
asymmetry
Transverse sliding osteotomy
sliding Double lateral
osteotomy
Oblique sliding wedge
ostectomy
Vertical Reduction Genioplasty
• vertical height changes can be obtainedvertical height changes can be obtained duringduri...
Wedge vertical reduction ostectomy allows for anteroposterior
repositioning in addition to (B) vertical shortening.
Technique to increase chin height
Vertical Augmentation
IndicationIndication
to increase the lower facial height, especially when theto increase the lower f...
Alloplastic Augmentation
• The use of alloplasts affords the possibility of notThe use of alloplasts affords the possibili...
•Alloplasts are still somewhatAlloplasts are still somewhat
controversialcontroversial, in that they have been, in that th...
• Place­ment through the submental fold can be combined withPlace­ment through the submental fold can be combined with ope...
• Implants can be used to lengthen the anteriorImplants can be used to lengthen the anterior
mandibular dimension by exten...
• Augmentation using implants
• Autologous - Calvarial bone
• Metals - Corrosive & High rate of bone erosion
• Polymers – ...
• Polymers – carbon chain based molecules with
crosslinking
• Dimethylsiloxanes Silicone based Silastic○ ○
• Polyamide Sup...
Soft Tissue Closure
• Redistribution of soft tissues may cause chinRedistribution of soft tissues may cause chin
ptosis if...
Soft Tissue Changes
• Soft tissue changes associated with genioplastySoft tissue changes associated with genioplasty
are h...
• Several surgical considerations will ensure a greater and moreSeveral surgical considerations will ensure a greater and ...
Complications
• Prolonged neurosensory disturbanceProlonged neurosensory disturbance
• Avascular necrosis of mobilized seg...
References
•Fonseca vol –IIFonseca vol –II
•Johan P Reyneke – Essentials of orthognathic surgery
Genioplasty
Genioplasty
Genioplasty
Genioplasty
Genioplasty
Genioplasty
Genioplasty
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Genioplasty

  1. 1. Genioplasty By – Dr. Shalini Singh PG OMFS
  2. 2. Contents •Introduction •Anatomy •Preoperative evaluation • Facial analysis • Cephalometric evaluation •History of genial procedures •Chin classification •Various techniques to correct deformities of chin • Osseous genioplasty • Alloplastic genioplasty •Complications •Conclusion •References
  3. 3. Introduction • Genioplasty is the surgical procedure used to alter the size and morphology of the bony chin with concomitant changes in the surrounding soft tissues. It can be used as a single procedure or it can be used as an adjunctive procedure along with other major osteotomies of the jaw.
  4. 4. Anatomy
  5. 5. Anatomy
  6. 6. Preoperative Evaluation • Chin deformitiesChin deformities can manifest incan manifest in three dimensionsthree dimensions, but, but the vast majority is in the horizontal planethe vast majority is in the horizontal plane.. • Analysis --Analysis --scrutiny of the skeletal, dental, and soft tissuescrutiny of the skeletal, dental, and soft tissue structures.structures. • Vertical balanceVertical balance of the face can be judged by usingof the face can be judged by using relative size and proportions of the various structures.relative size and proportions of the various structures. • Harmony is more important than absoluteHarmony is more important than absolute proportionalityproportionality.. • These include lip position, shape and depth of theThese include lip position, shape and depth of the labiomental fold, and the soft tissue envelope coveringlabiomental fold, and the soft tissue envelope covering the mandibular symphysis.the mandibular symphysis.
  7. 7. CEPHALOMETRIC EVALUATION • Down's,Down's, Steiner's,Steiner's, andand Tweed'sTweed's analysesanalyses The bony chin position can be evaluated in the anteroposterior (AP) dimension by using Sella-Nasion (SN)-pogonion (range, 72 to 88 degrees; mean, 80 degrees), SN-B point (72 to 87 degrees; mean, 79 degrees). Other cephalometric evaluations also exist, includ­ing the Y growth axis (range, 53 to 66 de­grees; mean, 59 degrees).
  8. 8. SOFT TISSUE EVALUATION • Gonzales-Ulloa andGonzales-Ulloa and StevensStevens, in which a, in which a line is constructedline is constructed perpendicular to theperpendicular to the Frankfort horizontalFrankfort horizontal and passing throughand passing through the soft tissue nasion.the soft tissue nasion. The soft tissue chinThe soft tissue chin should be tangent toshould be tangent to this linethis line..
  9. 9. Merrifield's "Z" angle • is a line from the soft tissue chin tangent to the most pro­cumbent lip,is a line from the soft tissue chin tangent to the most pro­cumbent lip, which forms an angle with the Frankfort horizontal.which forms an angle with the Frankfort horizontal. • The upper lip should fall on the profile line, with the lower lip tangent toThe upper lip should fall on the profile line, with the lower lip tangent to or slightly behind the profile line.or slightly behind the profile line.
  10. 10. Ricketts aesthetic plane • a line from the tip of the nose to the chin. He found thata line from the tip of the nose to the chin. He found that in aesthetically pleasing profiles,in aesthetically pleasing profiles, the upper lip was 4 mmthe upper lip was 4 mm and the lower lip 2 mm behind the aesthetic planeand the lower lip 2 mm behind the aesthetic plane..
  11. 11. • HoldawayHoldaway suggested a line tangent to the chin andsuggested a line tangent to the chin and upper lip. This line forms an angle with a lineupper lip. This line forms an angle with a line between the nasion and basion and should be aboutbetween the nasion and basion and should be about 7 to 9 degrees.7 to 9 degrees.
  12. 12. • ZimmerZimmer proposed a line from theproposed a line from the anterior nasal spineanterior nasal spine toto Down's "B" pointDown's "B" point and demonstrated that the nose and lips,and demonstrated that the nose and lips, as well as the chin, were almost identical in thickness whenas well as the chin, were almost identical in thickness when compared with this plane and that the nose had ancompared with this plane and that the nose had an approximate ratio of 2:1 to any of the other soft tissueapproximate ratio of 2:1 to any of the other soft tissue structures.structures.
  13. 13. COGS (cephalometric analysis for orthognathic surgery) B – Pg (ll MP): This is the distance from point B to a line perpendicular to mandibular plane through pogonion. This short line describes the prominence of the chin related to mandibular denture base. B – Pog (ll HP) = 7.2 ± 1.9
  14. 14. N – B (ll HP): This is also measured in a plane parallel to HP from point B to the perpendicular line dropped from N. This measurement describes the horizontal position of the apical base of the mandible in relation to N. normal value = -6.9 +/- 4.3 N – Pg (ll HP): This is measured in the same manner as N-A and N-B and indicates the prominence of the chin. Normal value = -6.5 +/- 5.1
  15. 15. • SteinerSteiner also used soft tissue components to define pleasingalso used soft tissue components to define pleasing profiles. He constructed a plane from the middle of the columella,profiles. He constructed a plane from the middle of the columella, midway between the curves of the upper lip and nasal tip. The lipsmidway between the curves of the upper lip and nasal tip. The lips should fall on this line.should fall on this line.
  16. 16. • All cephalometric assessments should be critically weighedAll cephalometric assessments should be critically weighed against clinical judgment and the individual needs of theagainst clinical judgment and the individual needs of the patient.patient. • The aesthetic desires of the patient should be a priority andThe aesthetic desires of the patient should be a priority and the clinical and radiographic assessment used to achieve thatthe clinical and radiographic assessment used to achieve that endpoint.endpoint.
  17. 17. History of Genial Procedures • HoferHofer(1942) first described horizontal sliding osteotomy---(1942) first described horizontal sliding osteotomy--- extraoral incisionextraoral incision • Converse(Converse(1950), discussed the feasibility of bone grafts1950), discussed the feasibility of bone grafts introduced through intraoral approachesintroduced through intraoral approaches • Trauner and ObwegeserTrauner and Obwegeser, (1957), used the horizontal, (1957), used the horizontal osteotomy through an intraoral incision with de-gloving of theosteotomy through an intraoral incision with de-gloving of the anterior mandible.anterior mandible. • Converse and Wood-SmithConverse and Wood-Smith described various applicationsdescribed various applications and versatility of, the horizontal osteotomyand versatility of, the horizontal osteotomy • Reichenbach and colleaguesReichenbach and colleagues (1965)proposed wedge(1965)proposed wedge osteotomy and vertical shortening of the chin.osteotomy and vertical shortening of the chin. • Hinds and Kent(Hinds and Kent(1969) realize the importance of maintaining1969) realize the importance of maintaining the soft tissue attachment along the inferior segment and thethe soft tissue attachment along the inferior segment and the role of these attachments in achieving maximal soft tissuerole of these attachments in achieving maximal soft tissue changechange.
  18. 18. CHIN CLASSIFICATION: • Guyuron, et al. have put forth a system to convey abnormalities with the chin. it can serve as a useful means of documentation. • Class • I Macrogenia: horizontal, vertical, combined • II Microgenia: horizontal, vertical, combined • III Combined: horizontal macro/ vertical microgenia, horizontal microgenia/vertical macrogenia • IV Asymmetric: a) short, b) normal, c) long anterior facial height • V Witch’s Chin: soft tissue ptosis • VI Pseudomacrogenia: normal bony volume with excess soft tissue volume • VII Pseudomicrogenia: normal bone volume with retrogenia secondary to excessive maxillary growth and clockwise rotation of mandible • VIII Iatrogenic malposition   • Guyuron B, Michelow BJ and Willis L: Practical classification of chin  deformities. Aesthetic Plast Surg 19: 257, 1995.
  19. 19. Types of genioplasty •Osseous genioplasty •Alloplastic genioplasty Incisions •Intraoral- labial sulcus incision •Extraoral- submental incision
  20. 20. • Types of osseous genioplasty • Horizontal osteotomy with advancement • Horizontal osteotomy with AP reduction • Tenon technique • Double sliding horizontal osteotomy • Vertical reduction genioplasty • Vertical augmentation • Alloplastic genioplasty- different types of alloplast • Hydroxy apatite • Silastic • Hard tissue replacement
  21. 21. Horizontal Osteotomy with Advancement
  22. 22. Horizontal Osteotomy with Advancement
  23. 23. Double Sliding Horizontal Osteotomy
  24. 24. Overlapping Genioplasty
  25. 25. Horizontal Osteotomy with Anteroposterior Reduction
  26. 26. Tenon Technique---Michelet and associates 1974. • The tenon technique allows for mortising of the tenon into the mobilizedThe tenon technique allows for mortising of the tenon into the mobilized fragment when the chin is advanced. In the setback procedure, the tenonfragment when the chin is advanced. In the setback procedure, the tenon is reversed and the mobilized fragment is mortised into the mandibleis reversed and the mobilized fragment is mortised into the mandible.
  27. 27. Transverse deformities of chin • Transverse deficiencyTransverse deficiency • Transverse excessTransverse excess • Asymmetry of chinAsymmetry of chin
  28. 28. Widening/narrowing of chin
  29. 29. Correction of mandibular asymmetry Transverse sliding osteotomy
  30. 30. sliding Double lateral osteotomy
  31. 31. Oblique sliding wedge ostectomy
  32. 32. Vertical Reduction Genioplasty • vertical height changes can be obtainedvertical height changes can be obtained duringduring advancement or setbackadvancement or setback by altering the angle of theby altering the angle of the osteotomyosteotomy.. • Approximately 3 to 5 mmApproximately 3 to 5 mm • If it is desirable to greatly shorten the chin with orIf it is desirable to greatly shorten the chin with or without AP change, a wedge reduction is indicated.without AP change, a wedge reduction is indicated. • This can be accomplished using the tenon technique,This can be accomplished using the tenon technique, as well as horizontal osteotomy.as well as horizontal osteotomy.
  33. 33. Wedge vertical reduction ostectomy allows for anteroposterior repositioning in addition to (B) vertical shortening.
  34. 34. Technique to increase chin height
  35. 35. Vertical Augmentation IndicationIndication to increase the lower facial height, especially when theto increase the lower facial height, especially when the deficit is in the mandibular alveolus or symphysis.deficit is in the mandibular alveolus or symphysis. • accomplishedaccomplished by interpositional grafting or alloplasticby interpositional grafting or alloplastic implantimplant place­ment between the osteotomizedplace­ment between the osteotomized segments following horizontal osteotomy of thesegments following horizontal osteotomy of the mandible.mandible. • Autogenous bone and hydroxyapatite are the mostAutogenous bone and hydroxyapatite are the most commonly used materials. It is also possible to make APcommonly used materials. It is also possible to make AP changes, if desiredchanges, if desired
  36. 36. Alloplastic Augmentation • The use of alloplasts affords the possibility of notThe use of alloplasts affords the possibility of not only AP augmentation but also vertical and,only AP augmentation but also vertical and, more importantly, lateral augmentation.more importantly, lateral augmentation. • TheThe drawbacks of osseous genioplastydrawbacks of osseous genioplasty includeinclude the possibility of asymmetric advancement,the possibility of asymmetric advancement, inadvertent vertical changes, and narrowing ofinadvertent vertical changes, and narrowing of the anterior mandible with large advancements.the anterior mandible with large advancements. • The use of alloplasts with lateral extensions canThe use of alloplasts with lateral extensions can eliminate this problem.eliminate this problem.
  37. 37. •Alloplasts are still somewhatAlloplasts are still somewhat controversialcontroversial, in that they have been, in that they have been associated with underlying bony re­associated with underlying bony re­ sorption, postoperative infection,sorption, postoperative infection, and nonin­fectious inflammatoryand nonin­fectious inflammatory responses.responses. •A variety of surgical techniques canA variety of surgical techniques can be used for the insertion of anbe used for the insertion of an alloplastalloplast
  38. 38. • Place­ment through the submental fold can be combined withPlace­ment through the submental fold can be combined with openopen lipectomy or liposuctionlipectomy or liposuction.. IntraoralIntraoral surgical approaches include asurgical approaches include a vestibular incisionvestibular incision as previously described or a midline verticalas previously described or a midline vertical incision with a tunneling technique.incision with a tunneling technique. • Great care must be taken when using limited­access incisions toGreat care must be taken when using limited­access incisions to ensure symmetric placement of the implant, in addition toensure symmetric placement of the implant, in addition to appropriate positioning in a vertical plane.appropriate positioning in a vertical plane.
  39. 39. • Implants can be used to lengthen the anteriorImplants can be used to lengthen the anterior mandibular dimension by extending them below themandibular dimension by extending them below the anterior mandibular border, as well as to augmentanterior mandibular border, as well as to augment the parasymphyseal region to a greater extent thanthe parasymphyseal region to a greater extent than the single-piece osseous genioplasty.the single-piece osseous genioplasty. • Implants should be stabilized with transosseousImplants should be stabilized with transosseous wires or position screws to ensure immobility.wires or position screws to ensure immobility. • Bony resorption under alloplastsBony resorption under alloplasts has been seen inhas been seen in patients with hyperactive mentalis muscles and lippatients with hyperactive mentalis muscles and lip incompetence.incompetence. • Great care should be taken to diagnose theseGreat care should be taken to diagnose these problems before implant placement to avoid futureproblems before implant placement to avoid future complications.complications.
  40. 40. • Augmentation using implants • Autologous - Calvarial bone • Metals - Corrosive & High rate of bone erosion • Polymers – most commonly used
  41. 41. • Polymers – carbon chain based molecules with crosslinking • Dimethylsiloxanes Silicone based Silastic○ ○ • Polyamide Supramid○ • Polyethylene (polyester fiber) Mersilene (Polyethylene○ terephthalate) Dacron Medpor (porous polyethylene)○ ○ • Expanded polytetrafluoroethylene (PTFE) Gore-Tex Avanta○ ○ • PTFE Teflon Proplast I and II○ ○ • Polymethylmethacrylate (PMMA) Silicone chin implants • Composite polymer implants • Hard Tissue Replacement (HTR) PMMA +○ polyhydroxyethylmethacrylate and calcium hydroxide • Hydrophilic outer layer for osseointegration • Silastic implant with Dacron backing Increase interface soft○ tissue ingrowth
  42. 42. Soft Tissue Closure • Redistribution of soft tissues may cause chinRedistribution of soft tissues may cause chin ptosis if at least a two-layer closure is notptosis if at least a two-layer closure is not performed. It is essential that the mentalisperformed. It is essential that the mentalis muscle be accurately reapproximate.muscle be accurately reapproximate. • In general, the incision should be closed in twoIn general, the incision should be closed in two to three layers and a pressure dressing appliedto three layers and a pressure dressing applied to minimize hematoma formation and facilitateto minimize hematoma formation and facilitate soft tissue reattachmentsoft tissue reattachment
  43. 43. Soft Tissue Changes • Soft tissue changes associated with genioplastySoft tissue changes associated with genioplasty are highly variable.are highly variable. • Reports in the literature range from 0.6:1 to 1:1Reports in the literature range from 0.6:1 to 1:1 change in soft tissue compared with bonychange in soft tissue compared with bony advancement/setback or implant thickness.advancement/setback or implant thickness. • Vertical and horizontal reduction genioplastyVertical and horizontal reduction genioplasty appears to have the most variability in osseousappears to have the most variability in osseous to soft tissue change.to soft tissue change.
  44. 44. • Several surgical considerations will ensure a greater and moreSeveral surgical considerations will ensure a greater and more stable magnitude of bone-to-soft tissue change; the moststable magnitude of bone-to-soft tissue change; the most important appear to be limited periosteal stripping and meticulousimportant appear to be limited periosteal stripping and meticulous layered soft tissue reapposition, including reconstruction of thelayered soft tissue reapposition, including reconstruction of the mentalis muscle.mentalis muscle.
  45. 45. Complications • Prolonged neurosensory disturbanceProlonged neurosensory disturbance • Avascular necrosis of mobilized segmentsAvascular necrosis of mobilized segments • Hemorrhage causing lingual hematomaHemorrhage causing lingual hematoma • Possible airway compromisePossible airway compromise • Unaesthetic soft tissue changes such as chin ptosisUnaesthetic soft tissue changes such as chin ptosis • Excessive lower tooth displayExcessive lower tooth display • Bony resorption under alloplastsBony resorption under alloplasts • Devitalization of teethDevitalization of teeth • Mandibular fractureMandibular fracture • Creation of mucogingival problemsCreation of mucogingival problems • Asymmetry, andAsymmetry, and • An unaesthetic end resultAn unaesthetic end result
  46. 46. References •Fonseca vol –IIFonseca vol –II •Johan P Reyneke – Essentials of orthognathic surgery
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