Increase of bigonial distance after BSSO

[Pendejo]

Posterior mandibular widening secondary to advancement sagittal split osteotomy: A retrospective study

Patients sometimes spontaneously report a modification of the width of their lower face after an advancement bilateral sagittal split osteotomy (ABSSO…

www.sciencedirect.com

The first goal of the study was to assess the impact of ABSSO (advancement bilateral sagittal split osteotomy) on the BGD (bigonial distance), one day and one year after surgery. The second objective was to look for a possible relation between the increase of BGD and the amount of mandibular advancement.

All consecutive patients operated between August 2011 and October 2013 in our department for a class II malocclusion by mean of an isolated ABSSO were retrospectively included in the study. Concomitant wisdom tooth extraction was allowed. Patients operated with a combination of orthognathic procedures (ABSSO and mandibular contraction, and/or genioplasty, and/or Le Fort I maxillary osteotomy) and patients with incomplete records were excluded.

The technique used in the study was the Obwegeser-Dal Pont II technique.


Measurement methods
The amount of mandibular advancement was measured by comparison between pre- and postoperative lateral teleradiographies made in centric occlusal positionand taken one day and one year postoperatively. In order to be reproducible, measures were made between the anterior face of incisors or orthodontic brackets and projected on a horizontal axis (fig. 2).

Figure 2. Example of measures on lateral teleradiographies in centric occlusal position. A. Before surgery. B. Postoperative day 1 (radiological advancementhere is 7.362.45 = 4.91 mm).

The amount of posterior mandibular widening was assessed by measuring the variations of the BGD on frontal teleradio-graphies using the same chronology. Gonions were spotted as the most lateral points located on each mandibular angle (fig. 3).

Figure 3. Example of measures on frontal teleradiographies. A. Before surgery. B. Postoperative day 1. C. Postoperative year 1 (ICD = intercanthal distance;BGD = bigonial distance).

Intrinsic reliability was evaluated by measuring the medial intercanthal distance (ICD), considered as constant, on pre-operative and one day postoperative frontal teleradiographies (fig. 3).

Results
One day after surgery, BGD increased in all patients. Statistical analysis reported a significant mean increase of 9.8 mm(P<103). One year after surgery, mean BGD increase was 4 mm and remained significant compared with preoperative value(P<103). BGD decreased at one year postoperative in 9 patients (18%) comparatively to the preoperative measure. Schematic representation of all the BGD measures made by both evaluators shoved an ‘‘increase-decrease’’ profile (fig. 5).

Figure 5. Evolution of bigonial distance (BGD) measures for all the patients (black lines: measures made by investigator A; grey lines: measures made by investigator B).

Not significant relation was found between the amount of mandibular advancement and the postoperative variation of the BGD as shown by the absence of any specific pattern in the relation between these two variables (fig. 6).

Figure 6. Bigonial distance (BGD) evolution at one year postoperative according to mandibular advancement measured on lateral teleradiographies.

Figure 9. Clinical aspect of positive effect of lower face widening on a male patient. A. Before surgery. B. One year after surgery.

Discussion
BGD increase after ABSSO can first be explained by the anatomy. Because of the V-shape of the mandible, there will be an interference inside the osteotomy line during advancement of the dental arch, responsible for lateral displacement of the lateral valve on each side (fig. 7).

Figure 7. Schematic illustration of lateral movements of the lateral valves induced by dental arch advancement; superior view of the V-shaped mandible. Left: before advancement; right: after advancement.

The osteotomy technique may be of great importance in this phenomenon. In the technique described by Epker, residual lingual cortical bone on the lateral valve may interfere with the medial valve, responsible for a lateral flaring of the mandibular angles. The use of the Obwegeser-Dalpont II technique, may reduce these bony interferences, as the osteotomy is extended down to the basilar edge. The kind of fixation must also be considered. Semi-rigid fixation, might facilitate lateral flaring of mandibular angles. It would therefore be relevant to compare semi-rigid and rigid fixation. However, temporo-mandibular joint disorders seem to be more frequent when using rigid fixation techniques because of more severe modifications in condylar position induced by these devices.

Posterior mandibular widening seems to reduce one year aftersurgery, even if it remains significant. 9 patients(18%) showed a decrease in their posterior mandibular width at the one-year control. This was significantly observed in the youngest patients.

The hypothesis proposed in the study is that mandibular bone remodeling induced modifications in muscular strains is more important in young patients than in older ones.

Modifications induced by mandibular advancement on mus-cular strains and their effect on bone remodeling process mayexplain the decrease of posterior mandibular width one yearafter surgery in young patients.


TL;DR:

• Bigonial distance mean increase was 4mm after BSSO using the Obwegeser-Dal Pont II technique
• The bigonial distance decreased in some patients, especially on the younger ones.
• There was no relation between the amount of mandibular advancement and the increase of BGD.

 

[Pendejo]

I wanted to include a pic showing the diference between the Obwegeser-Dalpont and Epker method but i only could find this:

@Dr Shekelberg (or anybody else) do you think you could find a picture that shows the differences better?

 

[Deleted member 3990]

I wanted to include a pic showing the diference between the Obwegeser-Dalpont and Epker method but i only could find this:

View attachment 232587

@Dr Shekelberg (or anybody else) do you think you could find a picture that shows the differences better?

the cut at the ramus is different

 

[MogTheMogger]

absolute peak high iq, this is so motivating and ascending as fuuuuuuuuuck bro

 

[Pendejo]

the cut at the ramus is different

Yeah i know.

I just wanted a pic showing both methods from a superior view, like the one on the thread but with the Epker method too.

 

[reptiles]

Posterior mandibular widening secondary to advancement sagittal split osteotomy: A retrospective study

Patients sometimes spontaneously report a modification of the width of their lower face after an advancement bilateral sagittal split osteotomy (ABSSO…

www.sciencedirect.com

The first goal of the study was to assess the impact of ABSSO (advancement bilateral sagittal split osteotomy) on the BGD (bigonial distance), one day and one year after surgery. The second objective was to look for a possible relation between the increase of BGD and the amount of mandibular advancement.



The technique used in the study was the Obwegeser-Dal Pont II technique.


Measurement methods
The amount of mandibular advancement was measured by comparison between pre- and postoperative lateral teleradiographies made in centric occlusal positionand taken one day and one year postoperatively. In order to be reproducible, measures were made between the anterior face of incisors or orthodontic brackets and projected on a horizontal axis (fig. 2).

View attachment 232501


The amount of posterior mandibular widening was assessed by measuring the variations of the BGD on frontal teleradio-graphies using the same chronology. Gonions were spotted as the most lateral points located on each mandibular angle (fig. 3).
View attachment 232503


Intrinsic reliability was evaluated by measuring the medial intercanthal distance (ICD), considered as constant, on pre-operative and one day postoperative frontal teleradiographies (fig. 3).

Results
One day after surgery, BGD increased in all patients. Statistical analysis reported a significant mean increase of 9.8 mm(P<103). One year after surgery, mean BGD increase was 4 mm and remained significant compared with preoperative value(P<103). BGD decreased at one year postoperative in 9 patients (18%) comparatively to the preoperative measure. Schematic representation of all the BGD measures made by both evaluators shoved an ‘‘increase-decrease’’ profile (fig. 5).

View attachment 232506


Not significant relation was found between the amount of mandibular advancement and the postoperative variation of the BGD as shown by the absence of any specific pattern in the relation between these two variables (fig. 6).

View attachment 232515



View attachment 232526



Discussion
BGD increase after ABSSO can first be explained by the anatomy. Because of the V-shape of the mandible, there will be an interference inside the osteotomy line during advancement of the dental arch, responsible for lateral displacement of the lateral valve on each side (fig. 7).

View attachment 232528



The osteotomy technique may be of great importance in this phenomenon. In the technique described by Epker, residual lingual cortical bone on the lateral valve may interfere with the medial valve, responsible for a lateral flaring of the mandibular angles. The use of the Obwegeser-Dalpont II technique, may reduce these bony interferences, as the osteotomy is extended down to the basilar edge. The kind of fixation must also be considered. Semi-rigid fixation, might facilitate lateral flaring of mandibular angles. It would therefore be relevant to compare semi-rigid and rigid fixation. However, temporo-mandibular joint disorders seem to be more frequent when using rigid fixation techniques because of more severe modifications in condylar position induced by these devices.

Posterior mandibular widening seems to reduce one year aftersurgery, even if it remains significant. 9 patients(18%) showed a decrease in their posterior mandibular width at the one-year control. This was significantly observed in the youngest patients.

The hypothesis proposed in the study is that mandibular bone remodeling induced modifications in muscular strains is more important in young patients than in older ones.

Modifications induced by mandibular advancement on mus-cular strains and their effect on bone remodeling process mayexplain the decrease of posterior mandibular width one yearafter surgery in young patients.


TL;DR:

• Bigonial distance mean increase was 4mm after BSSO using the Obwegeser-Dal Pont II technique
• The bigonial distance decreased in some patients, especially on the younger ones.
• There was no relation between the amount of mandibular advancement and the increase of BGD.

Very good fucking thread

 

[forwardgrowth]

Very good fucking thread

THIS IS FACT
what is better to fix jaw width IMDO or BSSO?
Can this method flare the gonion like this

 

[Sergio-OMS]

With IMDO the distance between the gonia gradually become shorter, although the mandible become wider just at the level of the first molars. That effect, along with the masseter muscles, widen the mandible more than with BSSO.

Hope this helps,

Sergio

 

[Pendejo]

With IMDO the distance between the gonia gradually become shorter, although the mandible become wider just at the level of the first molars.

So the bigonial distance becomes shorter compared to the rest of the mandible or IMDO actually decreases the bigonial distance?

 

[Sergio-OMS]

We haven't processed the whole data but the geometrical analysis on the computer of a single case would show a slight decrease of the distance between the gonia, as you can see here:

But, as I said, the whole effect would be as if the mandible became much wider than in BSSO. It is not all about some particular dots placed in the bones. As a matter of fact, as the mandibular intermolar distance increases, a larger amount of maxillary expansion is needed. That is normally a desired effect, isn't it?


Hope this helps,

Sergio

 

[Pendejo]

We haven't processed the whole data but the geometrical analysis on the computer of a single case would show a slight decrease of the distance between the gonia, as you can see here:

But, as I said, the whole effect would be as if the mandible became much wider than in BSSO. It is not all about some particular dots placed in the bones. As a matter of fact, as the mandibular intermolar distance increases, a larger amount of maxillary expansion is needed. That is normally a desired effect, isn't it?


Hope this helps,

Sergio

Thanks for the answer.

@chadpreetinthemaking look at this.

 

[Darkstrand]

We haven't processed the whole data but the geometrical analysis on the computer of a single case would show a slight decrease of the distance between the gonia, as you can see here:

But, as I said, the whole effect would be as if the mandible became much wider than in BSSO. It is not all about some particular dots placed in the bones. As a matter of fact, as the mandibular intermolar distance increases, a larger amount of maxillary expansion is needed. That is normally a desired effect, isn't it?


Hope this helps,

Sergio

Are you actually a maxillofacial surgeon?

 

[Sergio-OMS]

I am, indeed: https://www.linkedin.com/in/maxilofacial

 

[Ceamce]

I am, indeed: https://www.linkedin.com/in/maxilofacial

Veo que eres de españa, yo soy de Argentina y fui a una clinica oral y me dijeron que soy buen candidato a cirugía ortognatica. Puedes pasarte por mi post y ver mi foto de perfil y dejar una opinión? Habia gente que me recomendaba lefort 2 pero me parece algo exagerado.

 

[Sergio-OMS]

Veo que eres de españa, yo soy de Argentina y fui a una clinica oral y me dijeron que soy buen candidato a cirugía ortognatica. Puedes pasarte por mi post y ver mi foto de perfil y dejar una opinión? Habia gente que me recomendaba lefort 2 pero me parece algo exagerado.

No, lo siento, no puedo dar mi opinión con tan poca información. Sí que puedo decirte que hacer un Le Fort 2 me parece una locura.

 

[GetThatBread]

BSSO is the true ascension

 

[Darkstrand]

I am, indeed: https://www.linkedin.com/in/maxilofacial

What do you think of the idea of puncturing the nasal sutures up the remains of the frontal suture to achieve more harmonic expansion during MSE

 

[Sergio-OMS]

What do you think of the idea of puncturing the nasal sutures up the remains of the frontal suture to achieve more harmonic expansion during MSE

Does anybody do that?

 

[Darkstrand]

Does anybody do that?

I came up with this idea and I want to find someone that does that, I already heard from an orthodontist it theoretically should work, but I need someone to actually do this on me

 

[Sergio-OMS]

I came up with this idea and I want to find someone that does that, I already heard from an orthodontist it theoretically should work, but I need someone to actually do this on me

Well, we are almost 8 billion people, I am confident that you will.

 

[chadpreetinthemaking]

Thanks for the answer.

@chadpreetinthemaking look at this.

Bro cheers, im seriously consudering IMDO. This is a good thing right?

 

[Pendejo]

Bro cheers, im seriously consudering IMDO. This is a good thing right?

Did you see the video Sergio posted?
It would move the mandible forward and make it wider but the bigonial distance would decrease slightly.

I wonder if the decrease of the bigonial distance could be avoided by getting a BSSO + SARPE instead. @Sergio-OMS

 

[chadpreetinthemaking]

Did you see the video Sergio posted?
It would move the mandible forward and make it wider but the bigonial distance would decrease slightly.

I wonder if the decrease of the bigonial distance could be avoided by getting a BSSO + SARPE instead. @Sergio-OMS

I need SARPE the most tbh, narrow mouth/palate is such a failo, makes no sense that I would have it with a forward grown maxilla.

 

[Sergio-OMS]

Did you see the video Sergio posted?
It would move the mandible forward and make it wider but the bigonial distance would decrease slightly.

I wonder if the decrease of the bigonial distance could be avoided by getting a BSSO + SARPE instead. @Sergio-OMS

That inwards rotation of the mandibular gonia is negligible and the final effect on the size of the mandible is much larger and nicer with IMDO than with BSSO. And this is not counting on the effect of the upper maxillary expansion needed for IMDO.
Well, both BSSO and IMDO need a maxillary expansion (by means of SARPE, MSE or 2/3 piece Le Fort 1) but the expansion needed with IMDO is larger. This is good.

 

[Pendejo]

That inwards rotation of the mandibular gonia is negligible and the final effect on the size of the mandible is much larger and nicer with IMDO than with BSSO. And this is not counting on the effect of the upper maxillary expansion needed for IMDO.
Well, both BSSO and IMDO need a maxillary expansion (by means of SARPE, MSE or 2/3 piece Le Fort 1) but the expansion needed with IMDO is larger. This is good.

I understand.

Anyway what i wanted to ask on my comment was if MSDO combined with BSSO could replicate the results of IMDO without rotating the gonials inwards, i just confused MSDO with SARPE, my bad.

Do you think it would work?

 

[Sergio-OMS]

I understand.

Anyway what i wanted to ask on my comment was if MSDO combined with BSSO could replicate the results of IMDO without rotating the gonials inwards, i just confused MSDO with SARPE, my bad.

Do you think it would work?

I don't know, I have never combined BSSO + MSDO.

Using my basic knowledge on trigonometry I would say that MSDO widens the anterior mandible (including the chin and IMDO widens the posterior (maybe no the gonia, it widens at the level of the molars).

To be honest, I think this is just plain speculation. And IMDO post-op isn't easy in adults.

 

[Reoreyh]

Can I be confident of these gonial angle gains if I'm getting a BSSO or do I need to request this from my surgeon? How do I ask what technique he's using?

 

[superhans]

BSSO is the true ascension

it is most natural ascension, because you use your own bones, and not implants.

 

[GetThatBread]

it is most natural ascension, because you use your own bones, and not implants.

MSDO + MSE also, that’s basically a crazy fWHR increase + ascension

 

[Ceamce]

MSDO + MSE also, that’s basically a crazy fWHR increase + ascension

Msdo is a simple surgery?

 

[Sergio-OMS]

Msdo is a simple surgery?

It is not technically difficult. But, is it necessary? They are associated risks, something to think about.

 

[Ceamce]

It is not technically difficult. But, is it necessary? They are associated risks, something to think about.

because I am studying with an orthodontist to put on MSE. (mainly to improve breathing and widen the palate) and the upper part (which expands) should be aligned with the jaw

 

[Sergio-OMS]

because I am studying with an orthodontist to put on MSE. (mainly to improve breathing and widen the palate) and the upper part (which expands) should be aligned with the jaw

Your orthodontist will let you know if it is necessary. Normally a nice upper expansion is possible without the need of a MSDO procedure, only adjusting the inclination and position of the lower teeth.

 

[anti caking agents]

Can you do a BSSO if your occlusion is perfect in terms of molars a nd you only have a class II malocclusion due to overjet of the anterior upper incisors or would you need to combine it with a Lefort 1 in that case?

 

[kota]

Can you do a BSSO if your occlusion is perfect in terms of molars a nd you only have a class II malocclusion due to overjet of the anterior upper incisors or would you need to combine it with a Lefort 1 in that case?

You need to combine them to keep the occlusion.

 

[Sergio-OMS]

Can you do a BSSO if your occlusion is perfect in terms of molars a nd you only have a class II malocclusion due to overjet of the anterior upper incisors or would you need to combine it with a Lefort 1 in that case?

Sometimes doing just a BSSO is possible. + orthodontics, of course .

 

[Deleted member 4209]

big if true

 

[forwardgrowth]

I don't know, I have never combined BSSO + MSDO.

Using my basic knowledge on trigonometry I would say that MSDO widens the anterior mandible (including the chin and IMDO widens the posterior (maybe no the gonia, it widens at the level of the molars).

To be honest, I think this is just plain speculation. And IMDO post-op isn't easy in adults.

So the level of widening is not occurring at gonions but at the midpoint of the mandible at the second premolars..?

 

[Golden Glass]

No, lo siento, no puedo dar mi opinión con tan poca información. Sí que puedo decirte que hacer un Le Fort 2 me parece una locura.

Este foro está lleno de muchachos quien se quieren hacer las cirugías que ayuden a tener un viscerocraneo lo más atractivo posible.

Hay gente interesados en Lefort III y Orbital Box Ostoeotomy


¿Te molestaría si te mando mi radiografía por mensaje privado?

 

[Sergio-OMS]

So the level of widening is not occurring at gonions but at the midpoint of the mandible at the second premolars..?

At the level of the osteotomy, precisely.

 

[Pendejo]

Can I be confident of these gonial angle gains if I'm getting a BSSO or do I need to request this from my surgeon? How do I ask what technique he's using?

Ask him directly, the technique used in the study was the Obwegeser-Dal Pont II technique.

 

[PubertyMaxxer]

Your orthodontist will let you know if it is necessary. Normally a nice upper expansion is possible without the need of a MSDO procedure, only adjusting the inclination and position of the lower teeth.

How much mm can i expand with mse usually assuming i have perfect occlusion now without needing msdo, just using braces for teeth inclination?

 

[Sergio-OMS]

How much mm can i expand with mse usually assuming i have perfect occlusion now without needing msdo, just using braces for teeth inclination?

If you have a perfect occlusion the expansion will be limited by the torque of the lower molars, the bone around their roots and the willingness of your orthodontist to do that treatment.

maybe 10 mm tops? that’s being really optimistic about all those factors.

 

[PubertyMaxxer]

If you have a perfect occlusion the expansion will be limited by the torque of the lower molars, the bone around their roots and the willingness of your orthodontist to do that treatment.

maybe 10 mm tops? that’s being really optimistic about all those factors.

Woah thats a lot. lifefuel

 

[Sergio-OMS]

Woah thats a lot. lifefuel

Well don’t expect that result. And you need to start from a narrow palate and not so perfect occlusion (apparently perfect but not to the trained eye)

 

[PubertyMaxxer]

Well don’t expect that result. And you need to start from a narrow palate and not so perfect occlusion (apparently perfect but not to the trained eye)

If i could expand 8mm with mse and just get braces for inclination it would still hive me a mouthwidth and good cheekbone gains right?

 

[Sergio-OMS]

Effects on the cheekbones are more limited as there are more sutures to split and they are distant from the palate. Their distance would increase by 2-3 mm maybe ?

 

[Golden Glass]

Effects on the cheekbones are more limited as there are more sutures to split and they are distant from the palate. Their distance would increase by 2-3 mm maybe ?

People get implants there just to get a 3-4 mm increase so that would be good.

 

[forwardgrowth]

Effects on the cheekbones are more limited as there are more sutures to split and they are distant from the palate. Their distance would increase by 2-3 mm maybe ?

Can you perform MSE for aesthetics ?

 

[GetThatBread]

So MSDO can’t increase bigonial width and masculinize the lower jaw?

https://looksmax.org/threads/how-to-increase-bigonial-angle-mandible-width.87258/post-1507583

What about this vid? Does the lower jaw not increase laterally?