Received: 20 November 2013 Accepted: 6 June 2014 Available online 4 July 2014
Available online at
ScienceDirect www.sciencedirect.com
Technical note
Mandibular angle resection and masticatory muscle hypertrophy – A technical note and morphological optimization Re´section de l’angle mandibulaire et hypertrophie musculaire masticatoire – Note technique et optimisation morphologique A.R. Andreishcheva, R. Nicotb,*, J. Ferrib a
Department of Oral and Maxillofacial Surgery - St. Petersburg Pavlov State Medical University, Savushkina srt., 8/2, St., Petersburg, 197341, Russia b Oral and Maxillofacial Surgery Department, Lille 2 University, hoˆpital Roger-Salengro, boulevard du Professeur-Emile-Laine, 59037 Lille cedex, France
Summary Introduction. Mandibular angle resection is rarely used, but is a highly effective means of correcting facial defects. We report a mandibular angle resection technique associated with the removal of a part of hypertrophic masseter muscles and resection of buccal fat pad. Technical note. Anatomical reminders: the most important entities are the facial artery and vein, crossing the lower margin of the jaw just in front of the anterior boarder of the masseter muscle and the temporomaxillary vein, passing through the temporomaxillary fossa; preoperative aspects: the preoperative examination included a radiological assessment of the shape and size of the mandibular angle; surgical technique: an intra-oral approach was usually used. The most effective and convenient method for the osteotomy was using a reciprocating saw. This technique allowed achieving a smooth contour of masseter muscles during masticatory movements or at rest. Our experience. Eleven mandibular angle resections were performed from 2001 to 2009. The surgery was supplemented by remodeling the lower margin of the jaw for 5 other patients. No permanent facial palsy was noted. One patient presented a unilateral long-term loss of sensitivity of the lower lip and chin. Discussion. This surgical technique if simple even requires using good technical equipment, and observing a set of rules. Using these principles allows simplifying the surgical technique, and decreasing
Re´sume´ Introduction. La re´section chirurgicale de l’angle mandibulaire est une technique peu utilise´e qui est efficace dans la prise en charge des hypertrophies des muscles masse´ters. Nous rapportons la technique de re´section de l’angle mandibulaire associe´e a` l’exe´re`se partielle du muscle masse´ter hypertrophie´ et a` la re´section du corps adipeux de la joue. Note technique. Rappels anatomiques : les entite´s les plus importantes sont l’arte`re et la veine faciales qui croisent le bord infe´rieur de la mandibule en avant du muscle masse´ter et la veine re´tromandibulaire, passant dans la fosse temporo-maxillaire ; aspects pre´ope´ratoires : l’examen pre´ope´ratoire doit inclure une e´valuation radiologique de la forme et de la taille des angles mandibulaires ; la technique chirurgicale : l’abord habituel e´tait intra-oral. La me´thode utilise´e e´tait une oste´otomie a` la scie alternative pour remodeler les angles mandibulaires. Notre expe´rience. Entre 2001 et 2009, 11 re´sections des angles mandibulaires ont e´te´ effectue´s. Pour cinq autres patients, l’intervention chirurgicale a e´te´ comple´te´e par un remodelage de l’os basilaire de la mandibule. Aucune perturbation permanente des mouvements faciaux n’a e´te´ note´e. Dans un cas, il y a eu une hypoesthe´sie de la le`vre infe´rieure et du menton a` long terme. Discussion. Cette technique chirurgicale, simple sur le plan the´orique, impose ne´anmoins l’utilisation d’un mate´riel adapte´ et le respect d’un ensemble de re`gles. L’utilisation de ces principes
* Corresponding author. e-mail: [email protected] (R. Nicot). http://dx.doi.org/10.1016/j.revsto.2014.06.002 Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307 2213-6533/ß 2014 Elsevier Masson SAS. All rights reserved.
301
A.R. Andreishchev et al.
its morbidity. A part of the masseter muscles and the buccal fat pad can sometimes be resected to improve the morphological results. ß 2014 Elsevier Masson SAS. All rights reserved.
Keywords: Masseter muscle hypertrophy, Oral surgical procedures, Osteotomy
Introduction Mandibular angle resection is a seldom used surgical procedure, that significantly modify the shape of the face. As such, it is often used as a way of ‘‘refining’’ facial features, most often in young women with masseter muscle hypertrophy [1]. Mandibular angle resection is also considered for transsexual and interracial transitions [2]. Converse was the first to propose an intra-oral approach in 1951 [3] with the advantage of avoiding surgical skin scars and facial palsy. However, obtaining satisfactory esthetic results requires additional surgical procedures. We report a technique of mandibular angle resection associated with the removal of a part of hypertrophic masseter muscles and resection of buccal fat pad to optimize morphological results.
Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307
permet de simplifier l’acte chirurgical et de re´duire sa morbidite´. La re´section partielle des muscles masse´ters et de la boule de Bichat peut eˆtre pratique´e afin d’optimiser les re´sultats morphologiques. ß 2014 Elsevier Masson SAS. Tous droits re´serve´s.
Mots cle´s : Hypertrophie du muscle masse´ter, Technique de chirurgie orale, Oste´otomie
volume. We use the X-ray image and the relief of soft tissue to draw the projection of the future bone line on the skin. This line should start from the body of the mandible, where it curves before reaching the protrusion, the area of masseter muscles attachment. This line should end in the area curving into the posterior branch margin of the mandible, just above the tuberosity of the angle outer surface, corresponding to the muscle’s attachment area (fig. 1). Care should be taken to draw
Technical note Anatomy reminders The angle of the mandible is a bony protrusion; it is the attachment site for masseter and temporal muscles on its lateral side and for medial pterygoid muscle on its medial side. The degree of its development is dependent on the traction forces of the muscles attached to this area. The top of this area is limited by the mandibular canal, which contains the inferior alveolar neurovascular bundle. The most important entities, from a topographical point of view, are the facial artery and vein (a. et v. facialis), crossing through the lower boarder of the jaw, anteriorly to the masseter muscle, and the temporomaxillary vein (v. retromandibularis), passing through the temporomaxillary fossa.
Figure 1. Preoperative estimation before incision.
Preoperative aspects The preoperative examination must include radiological assessment of the shape and size of the mandibular angle. The simplest and most convenient method is a panoramic view. The primary contraindication for the operation is determined by X-ray results: a low mandibular canal excludes the possibility of resecting the bone fragment with adequate
302
Figure 2. Intra-oral approach in retromolar and at lower labio-gingival sulcus.
Mandibular angle resection and masticatory muscle hypertrophy
Figure 3. Intra-oral approach: dissected bone of lower jaw angulus and ramus.
symmetrical lines. This will ensure symmetry of the mandibular angles, after surgery.
Surgical technique The usual access for this surgical procedure was an intra-oral approach, conducted from the lower portion of the ascending ramus to the external oblique ridge, and extending to the second premolar region (fig. 2). The subperiosteal detachment extended from the level of the ramus incision up to the level of the first molar. The masseter muscle was completely detached from the mandibular angle, and the periosteum was elevated from posterior margin of the ramus and lower
Figure 4. Bone reduction with reciprocal saw.
margin of the mandible body (fig. 3). The most effective and convenient way to perform the osteotomy was using a reciprocating saw blade (fig. 4). A long saw placed through the intra-oral incision was set on the surface of the bone at an acute angle, determined by the elongation of the angle of the mouth soft tissues. Then, constantly monitoring the direction of the cut, the blade was moved toward the lower margin of mandible body. The saw blade was replaced with a shorter one to reduce the risk of bleeding associated with location of the facial artery and vein. Before removing the resulting bone fragment, the insertions of medial pterygoid muscle have to be detached. The osteotomy is described in (figs. 5 and 6).
Figure 5. Anterolateral view of the mandibular osteotomy. A. Design of the mandibular osteotomy. B. Mandible after mandibular angle resection.
303
A.R. Andreishchev et al.
Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307
Figure 6. Posterior view of the mandibular osteotomy. A. Design of the mandibular osteotomy. B. Mandible after mandibular angle resection.
The inner part of the masseter muscles was resected. This allowed obtaining a smooth contour of muscle during masticatory movements. Resection was performed as follows: anterior margin approach with scissors, separation of the lower part of the muscle on the inner and outer layers, then removal of the lower portion of the inner layer (fig. 7). Compliance with this technique allowed the surgeon to operate in a safe area where both branches of the facial nerve and Stensen’s duct pass over the top of the f. parotideomasseterica, which covered the masticatory muscles. There was also a separate category of patients who, in addition to hypertrophy of mandibular angles, presented with basal bone hypertrophy. Mandibular angle resection using the conventional technique did not solve the esthetic problem. Surgery for these patients was completed with resection of the bone in the lower margin of the mandibular body. The first step was the resection of the mandibular angle, after freeing the neurovascular bundle. This allowed the free use of the instrument in the area of the lower mandibular margin,
Figure 8. Resection of buccal fat pad.
without the risk of nerve damage. The bone excess was resected. In some cases, usually in overweight patients, surgery was completed with a resection of buccal fat pad to reduce the amount of tissue in the cheek area (fig. 8) and to emphasize the newly created contour of the lower jaw. An analogous intervention was performed on the opposite side. Incisions were sutured with interrupted sutures. Corrugated sheet drainage was set up. A tight compression bandage was applied to prevent formation of hematoma.
Results
Figure 7. Excision of lower-inner part of the masseter muscle.
304
We performed 11 mandibular angle resection procedures with the method described above from 2001 to 2009. The surgery was completed for 5 other patients, with remodeling of the lower boarder of the jaw (by filing or sawing). An important aspect of patient rehabilitation after mandibular angle resection surgery was recovery of neurological
Mandibular angle resection and masticatory muscle hypertrophy
Figure 9. Patient before surgery (a–c) and after surgery (d–f).
functions: facial muscle activity and sensitivity of the lips and chin. We did not observe any facial palsy. The lips of several patients remained asymmetrical when smiling or grinning, or even pursing (as if to whistle) in the first weeks following the operation. Two complications were observed when the bone section was performed with a short Lindermann bur instead of a reciprocal saw. In one case, there was a unilateral persistent loss of lip and chin sensitivity, which was associated with damage to the inferior alveolar neurovascular bundle. The cause of the damage was due to the difficulty to maintain a deep stable position for the short bur tip for the entire duration of the bone-burring procedure. We encountered a serious complication with profuse bleeding from the submandibular area, in another patient who required emergency care: blood transfusion and ligation of the external carotid artery. These incidents led us to stop performing burring procedures with a short Lindemann bur with the angular tip, due to poor control of the bur position and insufficient protection to the surrounding soft tissues. No case of bleeding or case requiring any additional measures were observed when osteotomies were performed with a reciprocal dental saw.
Globally, we significantly improved facial features (figs. 9–12) achieving a smooth contour of the soft tissues and bone, preserving the effectiveness of soft tissue support in adjacent areas, preventing ptosis of integumentary tissues, and decreasing the risk of damage to the inferior alveolar neurovascular bundle.
Discussion It was noted that: mandibular angle resection is highly effective for the correction of facial defects. The masseter muscles and buccal fat pads can be resected to enhance the esthetic effect; the bone should preferably be cut with a reciprocal saw; risk factors and adverse surgical prognosis include a thin subcutaneous fat layer, the patient’s age, and the need to resect a large amount of bone tissue.
Masticatory muscle hypertrophy can affect all masticatory muscles but masseters are the most commonly involved [1]. Masseter hypertrophy is a relatively uncommon condition,
305
A.R. Andreishchev et al.
Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307
Figure 11. Removed bone, muscle, and fat tissues. Two bone fragments on each side were removed by two ways. Figure 10. Panoramic X-ray before surgery (a) and after surgery (b).
usually asymptomatic. It leads to a protruding angle of the mandible, which alters facial contours. This typical aspect has been termed as ‘‘square face syndrome’’ in literature. These defects can only be corrected surgically [4]. The first masseter muscle resection was performed by Gurney [5], in 1947, via an extra-oral approach. Since then, various reports have been published for the optimization of morphological results. Adams [6] proposed, 2 years later, to associate a mandibular angle resection to the masseter myectomy. The intra-oral approach was introduced by Converse [3] in 1951 with the advantage of avoiding a face scar and minimizing the risk of injury to the marginal branch of the facial nerve. The optimization of morphological result, considering that patient complaints are mainly esthetic, has led most authors to recommend resecting any part of the masseter [1,3–7]. Bone hypertrophy is usually due to the hypertrophy of an attached muscle [4]. Therefore, resecting a hypertrophied mandibular angle requires resecting the basal inner portion of masticatory muscles. This allows obtaining a smooth contour of muscle during masticatory movements. On the other hand, some authors advocate performing only mandibular angle resection [8,9]. De Holanda Vasconcellos et al. [9] considered that removal of the muscle attachment region was sufficient to produce the necessary atrophy.
306
Figure 12. 3-D CT scan lower jaw reconstruction after surgery.
Various techniques have been used to perform the surgical contouring of the mandibular angle. We advocate, like Nishida et Iizuka [7], a full resection of the mandibular angle: resection of the almost entire length of bone of the outer compact layer creates a smooth contour; maintaining the internal compact layer without affecting the esthetic aspect keeps soft tissues in a stable position, preventing any sagging. This is especially important in elderly patients. Finally, it decreases the risk of damage to the inferior alveolar neurovascular bundle. The buccal fat pad includes a main section and 4 branches [10]. The main section lies just above Stensen’s
Mandibular angle resection and masticatory muscle hypertrophy
duct, extends along the lower ventral border of the masseter muscle, up to the ventral side of the maxillary vestibule, located opposite to the upper second molar. This anatomical location makes it important for the definition of facial shape [2,10], especially in patients with masseter muscle hypertrophy. Thus, buccal fat pad resection provides excellent esthetic results for a more harmonious and proportioned facial contour. It reduces the amount of tissue in the cheek area and underlines the newly created contour of the lower jaw.
[2] [3] [4] [5] [6]
[7]
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
[8] [9]
References [10] [1]
Roncevic´ R. Masseter muscle hypertrophy. Aetiology and therapy. J Maxillofac Surg 1986;14:344–8.
Altman K. Facial feminization surgery: current state of the art. Int J Oral Maxillofac Surg 2012;41:885–94. Converse JM. Deformities in the jaw. In: Converse JM, editor. Reconstructive . plastic surgery. Philadelphia: WB Saunders; 1977 Beckers HL. Masseteric muscle hypertrophy and its intra-oral surgical correction. J Maxillofac Surg 1977;5:28–35. Gurney CE. Chronic bilateral hypertrophy of the masseter muscles. Am J Surg 1947;73:137–9. Adams WM. Bilateral hypertrophy of the masseter muscle; an operation for the correction; case report. Br J Plast Surg 1949;2:78–81. Nishida M, Iizuka T. Intra-oral removal of the enlarged mandibular angle with masseteric hypertrophy. J Oral Maxillofac Surg 1995;53:1476–9. Wood GD. Masseteric hypertrophy and its surgical correction. Br Dent J 1982;152:416–7. de Hollanda Vasconcellos RJ, de Oliveira DM, do Egito Vasconcelos BC, Nogueira RV. Modified intra-oral approach to removal of mandibular angle for correction of masseteric hypertrophy: a technical note. J Oral Maxillofac Surg 2005;63: 1057–1060. Hasse FM, Lemperle G. Resection and augmentation of Bichat’s fat pad in facial contouring. Eur J Plast Surg 1994;17: 239–242.
307
Available online at
ScienceDirect www.sciencedirect.com
Technical note
Mandibular angle resection and masticatory muscle hypertrophy – A technical note and morphological optimization Re´section de l’angle mandibulaire et hypertrophie musculaire masticatoire – Note technique et optimisation morphologique A.R. Andreishcheva, R. Nicotb,*, J. Ferrib a
Department of Oral and Maxillofacial Surgery - St. Petersburg Pavlov State Medical University, Savushkina srt., 8/2, St., Petersburg, 197341, Russia b Oral and Maxillofacial Surgery Department, Lille 2 University, hoˆpital Roger-Salengro, boulevard du Professeur-Emile-Laine, 59037 Lille cedex, France
Summary Introduction. Mandibular angle resection is rarely used, but is a highly effective means of correcting facial defects. We report a mandibular angle resection technique associated with the removal of a part of hypertrophic masseter muscles and resection of buccal fat pad. Technical note. Anatomical reminders: the most important entities are the facial artery and vein, crossing the lower margin of the jaw just in front of the anterior boarder of the masseter muscle and the temporomaxillary vein, passing through the temporomaxillary fossa; preoperative aspects: the preoperative examination included a radiological assessment of the shape and size of the mandibular angle; surgical technique: an intra-oral approach was usually used. The most effective and convenient method for the osteotomy was using a reciprocating saw. This technique allowed achieving a smooth contour of masseter muscles during masticatory movements or at rest. Our experience. Eleven mandibular angle resections were performed from 2001 to 2009. The surgery was supplemented by remodeling the lower margin of the jaw for 5 other patients. No permanent facial palsy was noted. One patient presented a unilateral long-term loss of sensitivity of the lower lip and chin. Discussion. This surgical technique if simple even requires using good technical equipment, and observing a set of rules. Using these principles allows simplifying the surgical technique, and decreasing
Re´sume´ Introduction. La re´section chirurgicale de l’angle mandibulaire est une technique peu utilise´e qui est efficace dans la prise en charge des hypertrophies des muscles masse´ters. Nous rapportons la technique de re´section de l’angle mandibulaire associe´e a` l’exe´re`se partielle du muscle masse´ter hypertrophie´ et a` la re´section du corps adipeux de la joue. Note technique. Rappels anatomiques : les entite´s les plus importantes sont l’arte`re et la veine faciales qui croisent le bord infe´rieur de la mandibule en avant du muscle masse´ter et la veine re´tromandibulaire, passant dans la fosse temporo-maxillaire ; aspects pre´ope´ratoires : l’examen pre´ope´ratoire doit inclure une e´valuation radiologique de la forme et de la taille des angles mandibulaires ; la technique chirurgicale : l’abord habituel e´tait intra-oral. La me´thode utilise´e e´tait une oste´otomie a` la scie alternative pour remodeler les angles mandibulaires. Notre expe´rience. Entre 2001 et 2009, 11 re´sections des angles mandibulaires ont e´te´ effectue´s. Pour cinq autres patients, l’intervention chirurgicale a e´te´ comple´te´e par un remodelage de l’os basilaire de la mandibule. Aucune perturbation permanente des mouvements faciaux n’a e´te´ note´e. Dans un cas, il y a eu une hypoesthe´sie de la le`vre infe´rieure et du menton a` long terme. Discussion. Cette technique chirurgicale, simple sur le plan the´orique, impose ne´anmoins l’utilisation d’un mate´riel adapte´ et le respect d’un ensemble de re`gles. L’utilisation de ces principes
* Corresponding author. e-mail: [email protected] (R. Nicot). http://dx.doi.org/10.1016/j.revsto.2014.06.002 Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307 2213-6533/ß 2014 Elsevier Masson SAS. All rights reserved.
301
A.R. Andreishchev et al.
its morbidity. A part of the masseter muscles and the buccal fat pad can sometimes be resected to improve the morphological results. ß 2014 Elsevier Masson SAS. All rights reserved.
Keywords: Masseter muscle hypertrophy, Oral surgical procedures, Osteotomy
Introduction Mandibular angle resection is a seldom used surgical procedure, that significantly modify the shape of the face. As such, it is often used as a way of ‘‘refining’’ facial features, most often in young women with masseter muscle hypertrophy [1]. Mandibular angle resection is also considered for transsexual and interracial transitions [2]. Converse was the first to propose an intra-oral approach in 1951 [3] with the advantage of avoiding surgical skin scars and facial palsy. However, obtaining satisfactory esthetic results requires additional surgical procedures. We report a technique of mandibular angle resection associated with the removal of a part of hypertrophic masseter muscles and resection of buccal fat pad to optimize morphological results.
Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307
permet de simplifier l’acte chirurgical et de re´duire sa morbidite´. La re´section partielle des muscles masse´ters et de la boule de Bichat peut eˆtre pratique´e afin d’optimiser les re´sultats morphologiques. ß 2014 Elsevier Masson SAS. Tous droits re´serve´s.
Mots cle´s : Hypertrophie du muscle masse´ter, Technique de chirurgie orale, Oste´otomie
volume. We use the X-ray image and the relief of soft tissue to draw the projection of the future bone line on the skin. This line should start from the body of the mandible, where it curves before reaching the protrusion, the area of masseter muscles attachment. This line should end in the area curving into the posterior branch margin of the mandible, just above the tuberosity of the angle outer surface, corresponding to the muscle’s attachment area (fig. 1). Care should be taken to draw
Technical note Anatomy reminders The angle of the mandible is a bony protrusion; it is the attachment site for masseter and temporal muscles on its lateral side and for medial pterygoid muscle on its medial side. The degree of its development is dependent on the traction forces of the muscles attached to this area. The top of this area is limited by the mandibular canal, which contains the inferior alveolar neurovascular bundle. The most important entities, from a topographical point of view, are the facial artery and vein (a. et v. facialis), crossing through the lower boarder of the jaw, anteriorly to the masseter muscle, and the temporomaxillary vein (v. retromandibularis), passing through the temporomaxillary fossa.
Figure 1. Preoperative estimation before incision.
Preoperative aspects The preoperative examination must include radiological assessment of the shape and size of the mandibular angle. The simplest and most convenient method is a panoramic view. The primary contraindication for the operation is determined by X-ray results: a low mandibular canal excludes the possibility of resecting the bone fragment with adequate
302
Figure 2. Intra-oral approach in retromolar and at lower labio-gingival sulcus.
Mandibular angle resection and masticatory muscle hypertrophy
Figure 3. Intra-oral approach: dissected bone of lower jaw angulus and ramus.
symmetrical lines. This will ensure symmetry of the mandibular angles, after surgery.
Surgical technique The usual access for this surgical procedure was an intra-oral approach, conducted from the lower portion of the ascending ramus to the external oblique ridge, and extending to the second premolar region (fig. 2). The subperiosteal detachment extended from the level of the ramus incision up to the level of the first molar. The masseter muscle was completely detached from the mandibular angle, and the periosteum was elevated from posterior margin of the ramus and lower
Figure 4. Bone reduction with reciprocal saw.
margin of the mandible body (fig. 3). The most effective and convenient way to perform the osteotomy was using a reciprocating saw blade (fig. 4). A long saw placed through the intra-oral incision was set on the surface of the bone at an acute angle, determined by the elongation of the angle of the mouth soft tissues. Then, constantly monitoring the direction of the cut, the blade was moved toward the lower margin of mandible body. The saw blade was replaced with a shorter one to reduce the risk of bleeding associated with location of the facial artery and vein. Before removing the resulting bone fragment, the insertions of medial pterygoid muscle have to be detached. The osteotomy is described in (figs. 5 and 6).
Figure 5. Anterolateral view of the mandibular osteotomy. A. Design of the mandibular osteotomy. B. Mandible after mandibular angle resection.
303
A.R. Andreishchev et al.
Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307
Figure 6. Posterior view of the mandibular osteotomy. A. Design of the mandibular osteotomy. B. Mandible after mandibular angle resection.
The inner part of the masseter muscles was resected. This allowed obtaining a smooth contour of muscle during masticatory movements. Resection was performed as follows: anterior margin approach with scissors, separation of the lower part of the muscle on the inner and outer layers, then removal of the lower portion of the inner layer (fig. 7). Compliance with this technique allowed the surgeon to operate in a safe area where both branches of the facial nerve and Stensen’s duct pass over the top of the f. parotideomasseterica, which covered the masticatory muscles. There was also a separate category of patients who, in addition to hypertrophy of mandibular angles, presented with basal bone hypertrophy. Mandibular angle resection using the conventional technique did not solve the esthetic problem. Surgery for these patients was completed with resection of the bone in the lower margin of the mandibular body. The first step was the resection of the mandibular angle, after freeing the neurovascular bundle. This allowed the free use of the instrument in the area of the lower mandibular margin,
Figure 8. Resection of buccal fat pad.
without the risk of nerve damage. The bone excess was resected. In some cases, usually in overweight patients, surgery was completed with a resection of buccal fat pad to reduce the amount of tissue in the cheek area (fig. 8) and to emphasize the newly created contour of the lower jaw. An analogous intervention was performed on the opposite side. Incisions were sutured with interrupted sutures. Corrugated sheet drainage was set up. A tight compression bandage was applied to prevent formation of hematoma.
Results
Figure 7. Excision of lower-inner part of the masseter muscle.
304
We performed 11 mandibular angle resection procedures with the method described above from 2001 to 2009. The surgery was completed for 5 other patients, with remodeling of the lower boarder of the jaw (by filing or sawing). An important aspect of patient rehabilitation after mandibular angle resection surgery was recovery of neurological
Mandibular angle resection and masticatory muscle hypertrophy
Figure 9. Patient before surgery (a–c) and after surgery (d–f).
functions: facial muscle activity and sensitivity of the lips and chin. We did not observe any facial palsy. The lips of several patients remained asymmetrical when smiling or grinning, or even pursing (as if to whistle) in the first weeks following the operation. Two complications were observed when the bone section was performed with a short Lindermann bur instead of a reciprocal saw. In one case, there was a unilateral persistent loss of lip and chin sensitivity, which was associated with damage to the inferior alveolar neurovascular bundle. The cause of the damage was due to the difficulty to maintain a deep stable position for the short bur tip for the entire duration of the bone-burring procedure. We encountered a serious complication with profuse bleeding from the submandibular area, in another patient who required emergency care: blood transfusion and ligation of the external carotid artery. These incidents led us to stop performing burring procedures with a short Lindemann bur with the angular tip, due to poor control of the bur position and insufficient protection to the surrounding soft tissues. No case of bleeding or case requiring any additional measures were observed when osteotomies were performed with a reciprocal dental saw.
Globally, we significantly improved facial features (figs. 9–12) achieving a smooth contour of the soft tissues and bone, preserving the effectiveness of soft tissue support in adjacent areas, preventing ptosis of integumentary tissues, and decreasing the risk of damage to the inferior alveolar neurovascular bundle.
Discussion It was noted that: mandibular angle resection is highly effective for the correction of facial defects. The masseter muscles and buccal fat pads can be resected to enhance the esthetic effect; the bone should preferably be cut with a reciprocal saw; risk factors and adverse surgical prognosis include a thin subcutaneous fat layer, the patient’s age, and the need to resect a large amount of bone tissue.
Masticatory muscle hypertrophy can affect all masticatory muscles but masseters are the most commonly involved [1]. Masseter hypertrophy is a relatively uncommon condition,
305
A.R. Andreishchev et al.
Rev Stomatol Chir Maxillofac Chir Orale 2014;115:301-307
Figure 11. Removed bone, muscle, and fat tissues. Two bone fragments on each side were removed by two ways. Figure 10. Panoramic X-ray before surgery (a) and after surgery (b).
usually asymptomatic. It leads to a protruding angle of the mandible, which alters facial contours. This typical aspect has been termed as ‘‘square face syndrome’’ in literature. These defects can only be corrected surgically [4]. The first masseter muscle resection was performed by Gurney [5], in 1947, via an extra-oral approach. Since then, various reports have been published for the optimization of morphological results. Adams [6] proposed, 2 years later, to associate a mandibular angle resection to the masseter myectomy. The intra-oral approach was introduced by Converse [3] in 1951 with the advantage of avoiding a face scar and minimizing the risk of injury to the marginal branch of the facial nerve. The optimization of morphological result, considering that patient complaints are mainly esthetic, has led most authors to recommend resecting any part of the masseter [1,3–7]. Bone hypertrophy is usually due to the hypertrophy of an attached muscle [4]. Therefore, resecting a hypertrophied mandibular angle requires resecting the basal inner portion of masticatory muscles. This allows obtaining a smooth contour of muscle during masticatory movements. On the other hand, some authors advocate performing only mandibular angle resection [8,9]. De Holanda Vasconcellos et al. [9] considered that removal of the muscle attachment region was sufficient to produce the necessary atrophy.
306
Figure 12. 3-D CT scan lower jaw reconstruction after surgery.
Various techniques have been used to perform the surgical contouring of the mandibular angle. We advocate, like Nishida et Iizuka [7], a full resection of the mandibular angle: resection of the almost entire length of bone of the outer compact layer creates a smooth contour; maintaining the internal compact layer without affecting the esthetic aspect keeps soft tissues in a stable position, preventing any sagging. This is especially important in elderly patients. Finally, it decreases the risk of damage to the inferior alveolar neurovascular bundle. The buccal fat pad includes a main section and 4 branches [10]. The main section lies just above Stensen’s
Mandibular angle resection and masticatory muscle hypertrophy
duct, extends along the lower ventral border of the masseter muscle, up to the ventral side of the maxillary vestibule, located opposite to the upper second molar. This anatomical location makes it important for the definition of facial shape [2,10], especially in patients with masseter muscle hypertrophy. Thus, buccal fat pad resection provides excellent esthetic results for a more harmonious and proportioned facial contour. It reduces the amount of tissue in the cheek area and underlines the newly created contour of the lower jaw.
[2] [3] [4] [5] [6]
[7]
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
[8] [9]
References [10] [1]
Roncevic´ R. Masseter muscle hypertrophy. Aetiology and therapy. J Maxillofac Surg 1986;14:344–8.
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