Surgically Assisted Rapid Palatal Expansion

Armamentarium

  • #9 Periosteal elevator

  • #15 Scalpel blade

  • Appropriate sutures

  • Army/Navy retractors

  • Bovie electrocautery

  • Cottle elevator

  • Fine straight osteotome (or spatula osteotome)

  • Hyrax expander and activation key (supplied by orthodontist if not previously cemented)

  • Local anesthetic with vasoconstrictor

  • Minnesota retractors

  • Neurosurgical patties

  • Oxymetazoline solution or 4% topical cocaine

  • Reciprocating saw blades

  • Reverse Langenbeck retractor

History of the Procedure

The procedure for transverse maxillary expansion by opening the midpalatal suture using an orthodontic appliance was first described by Angell more than a century ago. This concept initially was met with skepticism but later was repopularized through the works of several clinicians, including Issacson and Ingram and Haas, as a viable method of treating maxillary transverse deficiency. It was noted that palatal expansion may result in a forward and downward movement of the maxilla, due to resistance not entirely from the midpalatal suture, as was thought initially, but also from surrounding bony structures, such as an intact zygomatic buttress, the pterygoid plates, and the piriform aperture. The findings on the increased facial skeletal resistance to expansion at the zygomaticotemporal, zygomaticofrontal, and zygomaticomaxillary articulations have led to a better understanding of the anatomic barriers to expansion beyond the midpalatal suture ( Figure 37-1 ).

Figure 37-1
Areas of resistance in the facial skeleton.

Identification of the areas of resistance in the facial skeleton has prompted the development of various maxillary osteotomies to expand the maxilla in conjunction with the use of orthodontic expansion devices. An earlier surgical technique, a midpalatal split, was described by Brown. Steinhauser reported a maxillary expansion osteotomy without the use of distraction but with placement of iliac crest bone graft in the expansion gap. In 1999, bone-borne transpalatal distraction was introduced, suggesting that bone-borne devices may overcome some potential disadvantages of tooth-borne devices, such as undesirable movements of the abutment teeth during expansion.

Over the years, various technical modifications have been introduced, with an emphasis on procedures that can be performed on an ambulatory outpatient basis. Some surgeons advocated complete separation of all maxillary articulations and areas of resistance, whereas others advised against separation at the pterygomaxillary junction to avoid potential pterygoid plate fracture and ensuing complications.

Arguments in favor of leaving the pterygoid plates intact were based on two principles: first, that surgical separation at the pterygoid plates has not been shown to improve the expandability of the maxilla or prevent relapse in a consistent manner, and second, that surgically assisted rapid palatal expansion (SARPE) should not be done as an office procedure under intravenous sedation if a surgeon decides to perform surgical separation at the pterygoid plates or nasal septum, because these maneuvers may increase the risk of significant bleeding, without any proven benefit.

As a measure to ensure the mobility of maxillary segments and symmetric expansion, some have proposed the use of two paramedian palatal osteotomies, in addition to the midline and lateral osteotomies. The paramedian palatal osteotomy cuts are made from the posterior nasal spine to a point posterior to the incisive canal. The question of what is the minimal procedure required to produce consistent and stable maxillary expansion in adults has yet to be answered. Regardless of which surgical modification is used, based on the surgeon’s training and preference, SARPE has become an important treatment modality for management of maxillary transverse deficiency in all types of malocclusions.

History of the Procedure

The procedure for transverse maxillary expansion by opening the midpalatal suture using an orthodontic appliance was first described by Angell more than a century ago. This concept initially was met with skepticism but later was repopularized through the works of several clinicians, including Issacson and Ingram and Haas, as a viable method of treating maxillary transverse deficiency. It was noted that palatal expansion may result in a forward and downward movement of the maxilla, due to resistance not entirely from the midpalatal suture, as was thought initially, but also from surrounding bony structures, such as an intact zygomatic buttress, the pterygoid plates, and the piriform aperture. The findings on the increased facial skeletal resistance to expansion at the zygomaticotemporal, zygomaticofrontal, and zygomaticomaxillary articulations have led to a better understanding of the anatomic barriers to expansion beyond the midpalatal suture ( Figure 37-1 ).

Figure 37-1
Areas of resistance in the facial skeleton.

Identification of the areas of resistance in the facial skeleton has prompted the development of various maxillary osteotomies to expand the maxilla in conjunction with the use of orthodontic expansion devices. An earlier surgical technique, a midpalatal split, was described by Brown. Steinhauser reported a maxillary expansion osteotomy without the use of distraction but with placement of iliac crest bone graft in the expansion gap. In 1999, bone-borne transpalatal distraction was introduced, suggesting that bone-borne devices may overcome some potential disadvantages of tooth-borne devices, such as undesirable movements of the abutment teeth during expansion.

Over the years, various technical modifications have been introduced, with an emphasis on procedures that can be performed on an ambulatory outpatient basis. Some surgeons advocated complete separation of all maxillary articulations and areas of resistance, whereas others advised against separation at the pterygomaxillary junction to avoid potential pterygoid plate fracture and ensuing complications.

Arguments in favor of leaving the pterygoid plates intact were based on two principles: first, that surgical separation at the pterygoid plates has not been shown to improve the expandability of the maxilla or prevent relapse in a consistent manner, and second, that surgically assisted rapid palatal expansion (SARPE) should not be done as an office procedure under intravenous sedation if a surgeon decides to perform surgical separation at the pterygoid plates or nasal septum, because these maneuvers may increase the risk of significant bleeding, without any proven benefit.

As a measure to ensure the mobility of maxillary segments and symmetric expansion, some have proposed the use of two paramedian palatal osteotomies, in addition to the midline and lateral osteotomies. The paramedian palatal osteotomy cuts are made from the posterior nasal spine to a point posterior to the incisive canal. The question of what is the minimal procedure required to produce consistent and stable maxillary expansion in adults has yet to be answered. Regardless of which surgical modification is used, based on the surgeon’s training and preference, SARPE has become an important treatment modality for management of maxillary transverse deficiency in all types of malocclusions.

Indications for the Use of the Procedure

The general indications for SARPE are skeletal maturity, transverse maxillary deficiency, excessive display of buccal corridors when smiling, and anterior dental crowding. Any clinical situation in which orthodontic expansion has failed should be evaluated for potential sutural resistance to expansion. For many clinicians, the patient’s age and the degree of skeletal maturity are the basis for considering nonsurgical expansion rather than SARPE. It has been shown that ossification of the midpalatal suture has wide variations in various age groups. In general, SARPE is recommended for patients over 16 years of age. Nonsurgical expansion can be a reasonable consideration for patients younger than 12 years of age. However, for patients over the age of 14, surgical corticotomies are essential to address the areas of resistance to expansion. SARPE is also indicated as phase 1 surgery in the early stage of orthodontic arch alignment and in preparation for future maxillary osteotomies for other vertical and anterior-posterior (AP) discrepancies. In addition, it may help obviate the need for complex segmentalization of the maxilla and hence avoid complications associated with segmental osteotomies.

In summary, indications for SARPE include:

  • 1.

    Increasing the maxillary arch perimeter so as to correct unilateral or bilateral posterior crossbite, with or without additional surgical procedures for other discrepancies

  • 2.

    Increasing the maxillary transverse width, especially when the transverse discrepancy is greater than 5 mm

  • 3.

    Alleviating dental crowding when bicuspid extractions are not indicated

  • 4.

    Reducing excessively prominent and visible buccal corridors when smiling

  • 5.

    Overcoming resistance at the sutures and bony articulations when orthopedic maxillary expansion has failed

The determination of maxillary transverse discrepancy is based on identification of the problem as absolute or relative. An absolute transverse discrepancy is a true horizontal width deficiency in the maxilla, whereas a relative transverse discrepancy is a result of the discrepancy in the maxilla or both jaws in the AP plane. Placing diagnostic models in Class I occlusion can be helpful for differentiating between absolute and relative transverse discrepancy. It also can yield valuable information about the location and nature of a maxillary transverse constriction.

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Jun 3, 2016 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Surgically Assisted Rapid Palatal Expansion
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