Monobloc and Facial Bipartition Osteotomies

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Monobloc and facial bipartition osteotomies Ramon L. Ruiz, DMD, MD a,b,c,d, * , Timothy A. Turvey, DDS a,c , Paul S. Tiwana, DDS, MD a a Department of Oral and Maxillofacial Surgery, University of North Carolina at Chapel Hill, Brauer Hall, CB# 7450, Chapel Hill, NC 27599-7450, USA b Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA c Children’s Hospital of North Carolina, Chapel Hill, NC 27599, USA d University of North Carolina Craniofacial Center, Chapel Hill, NC 27599, USA Maxillofacial surgery underwent a dramatic evolution as a direct result of the experience gained by surgeons who managed the facial injuries seen during the trench warfare of World War I [1]. The surgical techniques pioneered for the repair of injuries that involved the maxil- lofacial structures often were applied to the craniofacial skeleton and subsequently provided the foundation for newer procedures used in the reconstruction of congenital deformities. In the strictest sense, craniofacial surgical procedures are defined as those in which a transcranial approach is used for access to the upper facial skeleton. Despite this distinction, however, most craniofacial procedures represent an extension of the original scientific principles and traditional techniques of maxillofacial surgery. Tessier was the first to describe an approach for the correction of the craniofacial anomalies associated with Crouzon and Apert syndromes using a Le Fort III osteotomy, which included a combined extracranial/transcranial approach, access via a coronal scalp flap, interpositional bone grafts for stabilization at the osteotomy sites, and an external fixation device [2–4]. Sub- sequent modifications [5–7] resulted in the development of the monobloc and facial bipartition procedures. More recently, the work of Posnick provides the most comprehensive description of the specific surgical techniques, additional technical refinements, and clinical examples of ideal functional and esthetic results in the correction of total midface deficiency associated with con- genital deformities [8–13]. In North America, Posnick’s numerous publications have established the role of the monobloc and facial bipartition procedures as viable reconstructive maneuvers in the craniofacial surgeon’s armamentarium. The purpose of this article is to provide the surgeon with an overview of the monobloc and facial bipartition procedures. The operative steps are described, with attention given to the in- dications for surgery and specific intraoperative, technical considerations. Indications The craniofacial dysostosis syndromes (Crouzon, Apert, Pfeiffer, Saethre-Chotzen, and Car- penter) are inherited forms of craniosynostosis in which there is also extensive involvement of the sutures of the midfacial skeleton. In addition to the cranial vault dysmorphology that results from craniosynostosis (usually bilateral coronal), affected patients exhibit a characteristic total midface deficiency that involves the orbits and maxilla. The surgical correction of the craniofacial anomalies of the craniofacial dysostosis syndromes requires at least three carefully sequenced stages of reconstruction [14,15]. Initially, release of the bilateral coronal synostosis with reshaping of the cranial vault is undertaken. The surgical Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131–148 * Corresponding author. E-mail address: [email protected] (R.L. Ruiz). 1061-3315/02/$ - see front matter Ó 2002, Elsevier Science (USA). All rights reserved. PII: S 1 0 6 1 - 3 3 1 5 ( 0 1 ) 0 0 0 0 8 - 7

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  • Monobloc and facial bipartition osteotomies

    Ramon L. Ruiz, DMD, MDa,b,c,d,*, Timothy A. Turvey, DDSa,c,Paul S. Tiwana, DDS, MDa

    aDepartment of Oral and Maxillofacial Surgery, University of North Carolina at Chapel Hill, Brauer Hall,

    CB# 7450, Chapel Hill, NC 27599-7450, USAbDepartment of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA

    cChildrens Hospital of North Carolina, Chapel Hill, NC 27599, USAdUniversity of North Carolina Craniofacial Center, Chapel Hill, NC 27599, USA

    Maxillofacial surgery underwent a dramatic evolution as a direct result of the experience

    gained by surgeons who managed the facial injuries seen during the trench warfare of World

    War I [1]. The surgical techniques pioneered for the repair of injuries that involved the maxil-

    lofacial structures often were applied to the craniofacial skeleton and subsequently providedthe foundation for newer procedures used in the reconstruction of congenital deformities. In

    the strictest sense, craniofacial surgical procedures are dened as those in which a transcranial

    approach is used for access to the upper facial skeleton. Despite this distinction, however, most

    craniofacial procedures represent an extension of the original scientic principles and traditional

    techniques of maxillofacial surgery.

    Tessier was the rst to describe an approach for the correction of the craniofacial anomalies

    associated with Crouzon and Apert syndromes using a Le Fort III osteotomy, which included a

    combined extracranial/transcranial approach, access via a coronal scalp ap, interpositionalbone grafts for stabilization at the osteotomy sites, and an external xation device [24]. Sub-

    sequent modications [57] resulted in the development of the monobloc and facial bipartition

    procedures. More recently, the work of Posnick provides the most comprehensive description of

    the specic surgical techniques, additional technical renements, and clinical examples of ideal

    functional and esthetic results in the correction of total midface deciency associated with con-

    genital deformities [813]. In North America, Posnicks numerous publications have established

    the role of the monobloc and facial bipartition procedures as viable reconstructive maneuvers in

    the craniofacial surgeons armamentarium.The purpose of this article is to provide the surgeon with an overview of the monobloc and

    facial bipartition procedures. The operative steps are described, with attention given to the in-

    dications for surgery and specic intraoperative, technical considerations.

    Indications

    The craniofacial dysostosis syndromes (Crouzon, Apert, Pfeier, Saethre-Chotzen, and Car-penter) are inherited forms of craniosynostosis in which there is also extensive involvement of

    the sutures of the midfacial skeleton. In addition to the cranial vault dysmorphology that results

    from craniosynostosis (usually bilateral coronal), aected patients exhibit a characteristic total

    midface deciency that involves the orbits and maxilla.

    The surgical correction of the craniofacial anomalies of the craniofacial dysostosis syndromes

    requires at least three carefully sequenced stages of reconstruction [14,15]. Initially, release of

    the bilateral coronal synostosis with reshaping of the cranial vault is undertaken. The surgical

    Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

    * Corresponding author.

    E-mail address: [email protected] (R.L. Ruiz).

    1061-3315/02/$ - see front matter 2002, Elsevier Science (USA). All rights reserved.PII: S 1 0 6 1 - 3 3 1 5 ( 0 1 ) 0 0 0 0 8 - 7

  • technique used is similar to that for patients with nonsyndromic bilateral coronal synostosis.

    Bifrontal craniotomy is combined with frontoorbital advancement and cranial vault reshaping.

    In the second stage of reconstruction, correction of the total midface deciency is under-

    taken. The goal of this operative procedure is to improve cranial vault morphology further, nor-malize intracranial volume, and address further the problem of inadequate orbital depth. The

    authors prefer to carry out this stage of the reconstructive sequence at approximately age 5

    to 7, because the brain and cranioorbital structures have reached 80% to 90% of their adult size

    [16]. The operation can nalize the position of the orbits and shape of the forehead. Waiting

    until the permanent maxillary rst molars have erupted also decreases the likelihood of damag-

    ing these teeth and the developing second molars during the total midfacial osteotomy. It is at

    this stage in the reconstructive sequence of the craniofacial dysostosis syndromes that the mono-

    bloc and facial bipartition procedures may be applied. The exact timing of this operation alsodepends on the patients medical condition, functional neurologic concerns, and ophthalmologic

    situation. Patients with a marked degree of exorbitism are at risk for corneal injury, exposure

    keratitis, and disorders of ocular motility.

    Later in life, denitive orthognathic procedures are required to nalize the occlusion. The

    goal of second-stage reconstruction is to improve the contour and position of the orbits and

    forehead. Although the maxilla may be advanced into an ideal anteroposterior relationship with

    the mandible at the time of the monobloc osteotomy, it is not always possible to nalize the

    occlusion with this operation. It is predictable that in patients with craniofacial dysostosis therewill be continued normal mandibular growth combined with decient maxillary development,

    which results in a signicant class III malocclusion. These patients require denitive orthognathic

    surgery to nalize the position of the lower face and occlusion. The surgical-orthodontic treat-

    ment is usually planned once growth of the maxilla andmandible is complete (1418 years of age).

    The most common application for the monobloc facial advancement procedure is in the nal

    reconstruction of the cranioorbital deformities associated with Crouzon syndrome. The mono-

    bloc osteotomy allows for advancement of the orbits, nasal complex, and maxilla as one unit.

    This procedure allows nal repositioning of the orbits while addressing the total midface de-ciency present in these patients. In cases in which the amount of forward movement required

    is dierent for the orbits than it is for the maxilla, the procedure allows for dierential move-

    ments, which is accomplished by further osteotomizing and recontouring the frontoorbital ban-

    deau after the midface has been advanced. In cases in which the position and contour of the

    forehead and superior orbital rims are acceptable, a subcranial Le Fort III osteotomy may be

    used instead of the monobloc procedure. The decision regarding what type of osteotomy is car-

    ried out must be based on the specic skeletal dysmorphology and the anteroposterior position

    and contour of the frontoorbital region.Although there are similarities, the facial abnormalities associated with Apert syndrome

    generally are more pronounced and have less variation than those associated with Crouzon syn-

    drome. Patients with Apert syndrome also demonstrate downslanting palpebral ssures and

    an increased facial width with orbital hypertelorism. In patients with Apert syndrome, second-

    stage reconstruction is carried out using a facial bipartition procedure combined with repeat

    cranial vault reshaping during childhood. Facial bipartition allows the surgeon to nalize the

    orbital contours and position, correct the orbital hypertelorism, and advance the middle face.

    The midline split and excision of a central fragment of bone permits forward rotation of the lat-eral orbits and the elimination of the at face appearance characteristic of Apert syndrome

    [8]. In these patients there may be an abnormally large frontal sinus, which must be managed

    along with the extradural dead space at the time of surgery. The standard approach involves

    cranialization, meticulous removal of the mucosal lining, and obliteration with autogenous

    material (pericranial ap, free fat graft, bone graft).

    The facial bipartition procedure also has found application in the reconstruction of the facial

    deformity associatedwith craniofrontonasal dysplasia andatypicalmidline cleft anomalies. In cra-

    niofrontonasal and frontonasal dysplasia, the typical skeletal dysmorphology is characterizedby widening of the upper craniofacial segment and orbital hypertelorism (see Fig. 1). In general,

    the disproportionate skeletal growth is nonprogressive, and reconstruction of the midfacial

    skeleton should be delayed until the cranioorbital units are near skeletal maturity (57 years

    of age).

    132 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • Fig. 1. (A) Preoperative view of a 6-year-old child with craniofrontonasal dysplasia. She underwent primary

    cranioorbtial decompression and release of bilateral coronal synostosis during infancy and returned for second-stage

    midfacial surgery. Surgical reconstruction consisted of a facial bipartition procedure with additional reshaping of the

    anterior cranial vault. (B) Severe orbital hypertelorism and widening of the upper craniofacial skeleton are noted.

    (C) Stereolithographic model of the same patient with proposed osteotomy sites. (D) Intraoperative view after exposure

    through a coronal ap, osteotomies, and disimpaction with complete mobilization of the midface. The area of midline

    ostectomy has been measured and marked. (E) Fragment of frontonasal bone excised measuring 27 mm.

    (F) Repositioned facial halves with initial xation. The interface is then recontoured using a surgical handpiece.

    (G) Intraoperative view after xation of repositioned frontal bones and the use of calcium phosphate cement for anterior

    cranial vault reshaping. (H) Postoperative frontal view 1 year after surgery.

    133R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • Technique

    Coronal ap

    The coronal scalp incision is a versatile and cosmetically acceptable approach for accessto the cranial vault, cranial base, forehead, nose, upper middle face, and orbits. With the use

    of this approach, inferior eyelid or transconjunctival access to the orbit in most cases is not

    necessary.

    Fig. 1 (continued )

    134 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • The incision is placed from one supraauricular area to the other, and the degree of skeletalexposure required for a given procedure dictates the inferior extent of the incisions. When access

    to the zygoma and infraorbital rims is necessary, the incisions must be extended further infer-

    iorly. The hairline of the patient is a consideration in the placement of the incision. Although

    anterior extension at the midportion of the coronal ap may enhance ap retraction and access

    to the midface, the resulting scar subsequently may become obvious with male pattern baldness.

    The authors preference is to place the incision across the top of the head rather than carry it

    toward the forehead. The use of a postauricular coronal incision eliminates visible scars in

    Fig. 1 (continued )

    135R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • the preauricular area and decreases the risk to the frontal branch of the facial nerve in reoper-ated patients. Placement of this incision further posteriorly in the scalp is also benecial in

    children, in whom migration of the coronal scar may occur with growth. When secondary op-

    erations are performed, it is preferable to reincise through the original scar. Although it may be

    tempting to place the incision in a dierent location, consideration must be given to the eect of

    the previous scar on ap perfusion and wound healing. Use of a curved or sinusoidal (stealth)

    incision avoids a straight line scar and is particularly useful in patients with short hair.

    Initially, the proposed incision is injected with a diluted solution of 1% lidocaine with

    1:200,000 epinephrine. This solution reduces bleeding and helps dissection along the subapo-neurotic plane. Sterile saline may be injected freely into the subgaleal plane from the incision

    line to the forehead with the use of a spinal needle. The scalp has a rich vascular supply, so

    the incision is carried out in segments with the application of hemoclips. The authors preference

    is to begin with the bilateral supraauricular portions of the incision. Once the initial incision has

    been carried through the skin, two double-prong skin hooks are used to retract the wound edges

    outward. Blunt dissection with a surgical sponge or nger is then used through the loose sub-

    cutaneous connective tissue over each temporal extension to reach the temporalis fascia. Once

    the proper layer has been established, the superior portion of the coronal ap incision (superiortemporal ridge to superior temporal ridge) is made. Bipolar electrocautery is used to obtain

    hemostasis, which has a minimal eect on the adjacent peripheral hair follicles.

    Once the pericranium is identied, a plane of dissection is established above it. Dissection

    proceeds rapidly and bloodlessly to the forehead in this supraperiosteal plane.

    Fig. 1 (continued )

    136 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • Once the anterior cranial vault is reached, the dissection is converted to the subperiosteal

    plane. An incision is carried through periosteum approximately 2 to 4 cm posterior to the super-

    ior orbital rims. It is critical to remain within the subperiosteal plane during dissection over the

    facial skeleton to avoid injury to the facial nerve. Bleeding from vessels that perforate the cra-

    nium can be controlled with bone wax.When monobloc facial advancement is undertaken, the authors prefer a modication in this

    technique that allows for the elevation of a large pericranial ap. A standard postauricular skin

    incision is made and dissection is started forward in the supragaleal plane. The posterior edge of

    the skin ap is undermined and the monopolar electrocautery is used to incise through the peri-

    osteum 1 to 2 cm behind the incision line. The pericranium is raised as an intact ap. The right

    and left margins of the ap are created along the superior temporal ridges and its anterior base is

    meticulously preserved to maintain an adequate blood supply. Subperiosteal dissection con-

    tinues forward to expose the frontal bone and orbitozygomatic structures. Once the aps (cor-onal and pericranial) have been raised and they remain pedicled anteriorly, the pericranium is

    wrapped with a surgical sponge soaked with antibiotic-containing solution. This solution pro-

    tects the pericranium and prevents desiccation.

    In infants and young children, care must be exercised when dissecting over open sutures,

    especially midline sutures, to avoid venous sinus hemorrhage or injury to the meninges. In older

    children who have undergone previous cranial vault surgery, full-thickness cranial defects may

    remain and make dissection and elevation of the coronal ap more complicated. Care also must

    be exercised when establishing a plane of dissection over the temporalis muscle. The naturalplane of dissection is subgaleal. Within the region over the temporalis muscle, the plane should

    be deepened to the level of the muscle fascia (supercial layer of the deep temporal fascia). The

    temporoparietal fascia, which is supercial to the fascia of the temporalis muscle and is an ex-

    tension of the supercial musculoaponeurotic system, invests the temporal branch of the facial

    nerve. Deepening the incision to the level of the temporalis muscle fascia avoids the nerve and

    leads to subperiosteal dissection of the facial skeleton. The supraorbital nerves sometimes re-

    strict ap mobility and dissection of the periorbita. Removal of the bony oor of the foramina

    using a small osteotome is often required to release the supraorbital neurovascular bundles andpermit further forward mobility of the ap.

    Closure of the incision in layers, even after facial advancement that exceeds 15 mm, is usually

    not a problem. Before the coronal ap is repositioned, care should be taken to resuspend the

    lateral canthal tendons. The authors begin by using a small single-prong skin hook to grasp

    the tendon and lateral canthal soft tissues. Lateral canthopexy is then carried out using a non-

    resorbable suture material or ne stainless steel suture ligatures placed through the tendon and

    around the zygoma. Alternatively, a drill hole is made through the lateral orbital rim and the

    suture is attached. When a pericranial ap is not used, the pericranium may be closed using4-0 chromic gut sutures. The wound must be irrigated with copious normal saline solution be-

    fore closure. Once the skin ap is repositioned, closure of the coronal scalp ap is accomplished

    in layers beginning with interrupted 3-0 vicryl sutures, which are passed through the galea and

    reapproximate the subcutaneous tissues. Cutaneous closure typically has been accomplished

    using surgical staples that are maintained for 12 to 14 days. The authors have found the

    use of absorbable suture materials (chromic gut, vicryl rapide) to be favorable in the closure

    of coronal aps. This is especially true in pediatric cases in which the use of a resorbable

    material for closure obviates the need for staple or suture removal during the postoperativeperiod.

    Oral incisions

    The use of transoral approaches to the facial skeleton also provides wide exposure while con-

    cealing scars, which is an important component of the facial bipartition procedure. Typically,

    this procedure includes a small midline incision within the maxillary vestibule to create a seg-

    mental (sagittal) osteotomy of the maxilla. Although pterygomaxillary disimpaction may be car-ried out transorally, as performed during a Le Fort I level osteotomy, this requires a larger

    vestibular incision and area of dissection. The authors preference is to use an osteotome placed

    from above through the coronal ap for separation of the pterygomaxillary junction.

    137R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • The monobloc facial advancement procedure

    As described previously, the craniofacial skeleton is exposed through a coronal scalp ap ap-

    proach. Care must be taken to expose the nasal dorsum, internal aspect of the orbits, lateralorbital rims and lateral walls, and zygomatic arch (Fig. 2). After the soft tissue dissection, bi-

    frontal craniotomy is carried out and the frontal bone ap is removed (Fig. 3). The combination

    of intracranial and subcranial (anterior) approaches allows retraction and protection of the

    brain and globes so that the procedure may be carried out safely under direct visualization.

    A reciprocating saw is used to create a small osteotomy through the zygomatic arch (Fig. 4)

    and then a series of bone cuts through the lateral orbital wall down to the level of the inferior

    orbital ssure, temporal bone (Tenon extensions), and anterior cranial base (Figs. 58), [17].

    When the osteotomy is near the temporal fossa, adequate dissection of the fossa below the sphe-noid wing aords protection to the temporal lobe during the osteotomy procedure. This is espe-

    cially important in patients with Apert syndrome, in whom the temporal lobe tip may extend

    forward into the lateral orbital rim area.

    Extension of the osteotomy cuts through the medial orbital wall and orbital oor is then ac-

    complished with the use of a small osteotome. Care must be taken to avoid the infraorbital neuro-

    vascular bundle and the nasolacrimal apparatus.

    Separation of the nasal septal complex from the base of the skull is performed using a large

    osteotome directed transcranially from the anterior skull base (in front of the cribriform) to thelevel of the maxillary crest (Fig. 9). Typically, an oral endotracheal tube is used during the initial

    portion of the operative procedure. Once the nasal septum is divided, the patient may be con-

    verted over to a nasal endotracheal tube. In cases in which nasal intubation is used, meticulous

    care must be taken to avoid damaging the endotracheal tube during this osteotomy.

    Next, a long, curved osteotome is used to separate the maxilla from the pterygoid plates. This

    is approached from above through the coronal ap and a nger is placed over the medial surface

    Fig. 2. (A, B) Once the coronal ap is elevated, care is taken to expose the entire craniofacial complex so that the

    osteotomies may be carried out under direct visualization. This includes exposure of the nasal dorsum, internal walls of the

    orbits, and zygomatic arch in the subperiosteal plane. The temporalis muscle is elevated from the squamosal portion of the

    temporal bone,which allows access to the lateral orbital walls and the creation of Tenon extensions. (From Posnick JC.

    Craniofacial dysostosis syndromes: a staged reconstructive approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors.

    Facial clefts and craniosynostosis: principles and management. Philadelphia: W.B. Saunders; 1995; with permission.)

    138 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • of the pterygomaxillary junction to conrm complete separation and appropriate placement of

    the osteotome (Fig. 10).

    Once the osteotomies are completed, the bone cuts should be tested with a thin osteotome to

    identify areas of incomplete separation and prevent unintended fractures. Attempts to mobilize

    facial bones after incomplete osteotomies may result in fracture disruption of the segments,inadequate advancement, and relapse. These problems most frequently occur during movements

    at the Le Fort III or frontofacial (monobloc) levels. Inadequate separation of the posterior max-

    illary walls and perpendicular portion of the palatine bone, which are impossible to visualize

    completely, contributes to this problem and may result in disruption of the zygomatic portion

    Fig. 3. Transcranial access is provided through bifrontal craniotomy. Initially, bur holes are placed at the margins of the

    bone ap and on either side of the sagittal sinus, which allows for separation of the dura before the craniotome is used

    and the bone ap is elevated by the neurosurgeon. The frontal/superior orbital rim unit and Tenon extensions are

    outlined with a surgical marker before bur holes are placed. (From Posnick JC. Craniofacial dysostosis syndromes: a

    staged reconstructive approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors. Facial clefts and craniosynostosis:

    principles and management. Philadelphia: W.B. Saunders; 1995; with permission.)

    Fig. 4. Osteotomy through the midportion of the zygomatic arch is completed with a reciprocating saw. (From Posnick

    JC. Craniofacial dysostosis syndromes: a staged reconstructive approach. In: Turvey TA, Vig KWL, Fonseca RJ,

    editors. Facial clefts and craniosynostosis: principles and management. Philadelphia: W.B. Saunders; 1995; with

    permission.)

    139R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • of the orbit. The use of osteotomes and specially designed bone spreaders assists in the comple-

    tion of pterygomaxillary separation and minimizes the risk of associated fractures (Figs. 8, 10,

    and 11) [13]. When fractures do occur, complete mobilization still must be accomplished. Repair

    of the involved segments by plate xation is indicated; when this is appropriately performed it

    seldom results in a problem.Mobilization of the total midfacial skeletal unit is carried out with Rowe disimpaction for-

    ceps used to apply slow, controlled, downward force (Fig. 11). The authors preferred approach

    is to use a prefabricated occlusal splint and arch bars with wire maxillomandibular xation to

    stabilize the monobloc segment initially. Once the midface has been mobilized with the desired

    advancement achieved and the patient placed into maxillomandibular xation, attention may be

    directed to the application of rigid internal xation.

    Fig. 5. Orbital bone cuts begin by dividing the lateral orbital wall and continue inferiorly to the level of the inferior

    orbital ssure. An assistant places a malleable retractor within the orbit and retracts the periorbita. The osteotomy is

    completed under direct visualization. (From Posnick JC. Craniofacial dysostosis syndromes: a staged reconstructive

    approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors. Facial clefts and craniosynostosis: principles and

    management. Philadelphia: W.B. Saunders; 1995; with permission.)

    Fig. 6. Superiorly, the lateral orbital osteotomy is extended to join the inferior line of the Tenon extension. During this

    part of the operative procedure, a retractor is placed into the temporal fossa for protection of the temporal lobe. (From

    Posnick JC. Craniofacial dysostosis syndromes: a staged reconstructive approach. In: Turvey TA, Vig KWL, Fonseca

    RJ, editors. Facial clefts and craniosynostosis: principles and management. Philadelphia: W.B. Saunders; 1995; with

    permission.)

    140 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • The large skeletal movements carried out duringmonobloc facial advancements require careful

    stabilization for successful outcomes. Inadequate stabilization contributes to relapse and infec-

    tion, and the use of rigid xation minimizes these problems. The application of bone plates and

    screws for internal xation of the osteotomized segments is done beginning at the zygomatic ar-

    ches and lateral Tenon extensions. The authors preference is to use resorbable internal xation

    Fig. 7. The frontal lobes are gently retracted for access to the anterior cranial base. Osteotomy through the orbital roofs

    is carried out from above using the reciprocating saw, which is continued in front of the cribriform plate in the midline.

    (From Posnick JC. Craniofacial dysostosis syndromes: a staged reconstructive approach. In: Turvey TA, Vig KWL,

    Fonseca RJ, editors. Facial clefts and craniosynostosis: principles and management. Philadelphia: W.B. Saunders; 1995;

    with permission.)

    Fig. 8. A small osteotome is used to complete the osteotomies, which allows the surgeon to test potential areas where

    there has been incomplete separation and prevents unintended fractures. This is especially critical at pterion where

    complete division with the saw is dicult because of visualization. (From Posnick JC. Craniofacial dysostosis syndromes:

    a staged reconstructive approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors. Facial clefts and craniosynostosis:

    principles and management. Philadelphia: W.B. Saunders; 1995; with permission.)

    141R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • wherever possible. The recent evolution in resorbable (polylactic acid polymer) rigid xation sys-

    tems hasmade this an attractive option for stabilization of the craniomaxillofacial skeleton.When

    there is any question that the resorbable xation will withstand the soft tissue relapse forces

    encountered during midfacial advancements, titanium hardware is used for internal xation.

    The use of fresh autogenous bone grafts to ll osteotomy gaps provides the most predictableresults during orbital and midfacial procedures. Bone grafts are placed into the osteotomy gaps

    Fig. 9. A larger osteotome is then placed through the cranial fossa osteotomy in front of the cribriform and driven

    inferiorly to the level of the maxillary crest. The nasal septum is separated from the skull base. (From Posnick JC.

    Craniofacial dysostosis syndromes: a staged reconstructive approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors.

    Facial clefts and craniosynostosis: principles and management. Philadelphia: W.B. Saunders; 1995; with permission.)

    Fig. 10. Division at the pterygomaxillary junction is accomplished using a longer curved osteotome placed from above

    through the coronal ap. A nger is placed over the medial aspect of the pterygomaxillary junction to conrm placement

    of the osteotome and complete separation of the maxilla. Once disimpaction has been carried out, Posnick spreaders are

    used to mobilize the maxilla adequately. (From Posnick JC. Craniofacial dysostosis syndromes: a staged reconstructive

    approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors. Facial clefts and craniosynostosis: principles and

    management. Philadelphia: W.B. Saunders; 1995; with permission.)

    142 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • at the zygomatic arch, along the posterior margin of the advanced frontal bones, and to recon-

    struct the orbital oors after a monobloc advancement. These grafts are useful in restoring ana-

    tomic contours and contribute to the stability of the advanced segments. As a general rule,

    full-thickness bony defects of the cranial vault should be grafted to ensure adequate regener-

    ation and continuity. This is especially true in children older than 2 years of age, in whomfull-thickness skull defects of more than a few millimeters do not heal predictably. The use of

    split-thickness cranial grafts is favored because of proximity to the surgical site, ease of access

    through the same coronal ap, and quantities of bone available. The consistency of the bone

    in the cranium (dense cortical) and its rich haversian network allow it to revascularize quickly

    and resorb minimally. Calcium phosphate bone cements also may be used for the repair of full-

    thickness defects and recontouring the cranial vault (Fig. 1G).

    Modications for facial bipartition

    The facial bipartition procedure begins with the same surgical steps carried out during a

    monobloc facial advancement, which are carried out up to and including the complete disimpac-tion and mobilization of the midface. Before the facial halves may be translocated medially, two

    additional surgical maneuvers must be carried out. First, midline ostectomy is carried out and

    a segment of bone from the central face (frontonasal bones) must be removed (Figs. 12 and 1).

    The specic amount of bone removed varies depending on the individual patients deformity

    and is predetermined based on presurgical anthropometric and CT-based measurements. Second,

    the maxilla is segmentalized into two segments using a midline (sagittal) osteotomy (Fig. 13).

    A nasal-septal osteotome is used to separate the cartilaginous and bony septum from the max-

    illary crest. The maxilla is then divided in the sagittal plane using a small midline osteotomycreated with a bur and then an osteotome for completion.

    In addition to midfacial advancement, the division of the facial skeleton into two halves

    permits translocation of the orbits medially for the correction of hypertelorism and forward

    movement of the lateral orbital rims to correct the arch of the facial form (Fig. 14). The extents

    to which these movements may be carried out are limited primarily by the palatal soft tissues

    (Fig. 15). As the facial halves are translocated medially, the most notable change below the level

    of the orbits is a widening of the maxillary arch form. The forward advancement of the lateral

    Fig. 11. Disimpaction of the total midfacial unit is performed using Rowe disimpaction forceps to apply controlled,

    downward, and forward traction. (From Posnick JC. Craniofacial dysostosis syndromes: a staged reconstructive

    approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors. Facial clefts and craniosynostosis: principles and

    management. Philadelphia: W.B. Saunders; 1995; with permission.)

    143R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • orbital rims produces dierential widening, which aects the posterior maxilla. In patients un-

    dergoing facial bipartition who have preexisting constriction of the maxillary arch, as is seen in

    the craniofacial dysostosis syndromes, the surgeon encounters substantial resistance during

    these skeletal movements. This is especially the case in children with a history of cleft palate

    repair, in whom palatal scarring results in even greater maxillary transverse collapse and softtissue immobility.

    Fig. 12. Removal of a fragment of midline bone (frontal and nasal) during facial bipartition. It is often necessary to trim

    away any residual portions of ethmoidal bone and cartilaginous nasal septum that may interfere with translocation of

    the facial halves. Care must be taken to minimize tearing of the nasal mucosa. (From Posnick JC. Craniofacial dysostosis

    syndromes: a staged reconstructive approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors. Facial clefts and

    craniosynostosis: principles and management. Philadelphia: W.B. Saunders; 1995; with permission.)

    Fig. 13. Sagittal osteotomy of the maxilla as used in the bipartition procedure. (A) Small midline vestibular incision with

    exposure of the piriform rim, nasal oor, and septum. (B) Nasal-septal osteotome used for separation of the septum

    along the maxillary crest. (C and D) A straight osteotome is then used to complete the segmentalization, and small bone

    spreaders conrm mobility of the two maxillary halves. (From Posnick JC. Craniofacial dysostosis syndromes: a staged

    reconstructive approach. In: Turvey TA, Vig KWL, Fonseca RJ, editors. Facial clefts and craniosynostosis: principles

    and management. Philadelphia: W.B. Saunders; 1995; with permission.)

    144 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • Once the orbital medialization is complete, rigid internal xation is applied across the mid-

    line. The central region is xated before any bone plates are applied to the lateral Tenon exten-

    sions or zygomatic arches.

    Management of dead space

    The elimination of dead space during closure of the craniomaxillofacial region is critical for

    sound surgical practice. Dead space that results from craniofacial procedures is resolved by

    meticulous closure of tissues, placement of bone grafts, and obliteration with soft tissue aps

    or free fat.

    Forward advancements of the craniofacial skeleton during monobloc and bipartition proce-

    dures result in the creation of extradural, retrofrontal dead space and communication with the

    nasal cavity [11]. Potential complications of residual dead space include delayed healing, cere-brospinal uid leaks, and infection. The management of this space in the anterior cranium after

    frontofacial advancement remains controversial. Expansion of the frontal bones and relatively

    rapid lling of the residual intracranial space has been well demonstrated in infants and young

    children. This observation supports the conservative management of dead space in younger pa-

    tients. More gradual, and less complete, lling occurs in the adult, which may be particularly

    troublesome when the space communicates directly with the nasal cavity. Sealing the nasal

    cavity from the cranial fossa is accomplished with primary repair of the nasal mucosa.

    Because this is not usually feasible, the authors prefer to use an anteriorly based pericranialap inserted for coverage of the anterior cranial base. The use of brin glue in the recon-

    Fig. 14. Skeletal movements before (A) and after (B) facial bipartition. Notice that medial translocation of the upper

    facial halves to correct orbital hypertelorism also results in some degree of lateral movement involving the maxillary

    segments.

    145R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • struction of the anterior cranial oor also provides a temporary seal between the cavities and

    allows for re-epithelialization of the nasal mucosa. When forehead procedures are performed

    and the frontal sinuses are present, management of the dead space is achieved by cranialization,

    complete removal of the mucosal lining, and obliteration of the nasofrontal ducts with bone

    grafts or free fat.

    The placement of bone grafts into bony defects is important for closure of dead space and

    facilitates rapid healing. These bone grafts should be wedged or stabilized with screws to preventmigration. Defects within the temporal fossa after facial advancements also may be covered

    nicely with advancement of the temporalis muscles. This procedure eliminates the dead space,

    and the defect is conned to the hair-bearing area of the scalp.

    A layered closure of the coronal incision is required for elimination of dead space and an op-

    timal esthetic result. The lateral canthus is stripped during the exposure of the orbital rims, and

    these structures must be resuspended. Sutures are passed through the canthus and secured to the

    lateral orbital rim or temporalis muscle fascia. When the temporalis muscle is stripped from the

    lateral temporal crest or fossa, it should be reattached to the lateral orbital wall and temporalridge to prevent bitemporal defects. Closure of the subcutaneous tissues and galea is accom-

    plished as a separate layer.

    Until the nasopharyngeal mucosa seals, communications with the nasal cavity allow air leaks

    that may result in subcutaneous emphysema or a pneumocephalus. To prevent this type of air-

    ow, postoperative endotracheal intubation may be extended or bilateral nasopharyngeal air-

    ways placed for a 3- to 5-day period. Sinus precautions and restriction of nose blowing also

    further limit reux of air and uid during the postoperative period.

    Fig. 14 (continued)

    146 R.L. Ruiz et al. / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 131148

  • References

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    [2] Tessier P. Osteotomies totales de la face. Syndrome de crouzon, syndrome dapert: oxycephalies, scaphocephalies,

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    [3] Tessier P. Traitement des dysmorphies facials propres aux dysostoses craniofaciales, maladies de crouzon et dapert.

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    Fig. 15. (A) High arched palate and narrowed maxillary arch width are common ndings in children with craniofacial

    dysostosis syndromes and craniofrontonasal dysplasia. (B) During the facial bipartition, upper facial movements toward

    the midline result in lateral expansion of the maxillary arch form. Resistance is encountered from palatal soft tissues at

    this location.

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  • [4] Tessier P. Relationship of craniostenoses to craniofacial dysostosis and to faciostenosis: a study with therapeutic

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