Maxillectomy defect classifications cordeiro

upto date classification and options

1. MAXILLECTOMY DEFECT CLASSIFICATIONS
Type I defects (limited maxillectomy) include resection of one or two walls of the maxilla, excluding
the palate
Type II defects (subtotal maxillectomy) include resection of the maxillary arch, palate, anterior and
lateral walls (lower five walls), with preservation of the orbital floor
Type III defects (total maxillectomy) include resection of all six walls of the maxilla. This type of defect is
subdivided into type IIIa, where the orbital contents are preserved (Fig. 3), and type IIIb where the
orbital contents are exenterated
Type IV defects (orbitomaxillectomy) include resection of the orbital contents and the upper five
walls of the maxilla, with preservation of the palate
The concept of the maxilla as a six-sided box or hexahedrium has been described by several authors,
usually with regard to tumor ablation. The roof of the box is the floor of the orbit, and the base is the
palate . From the surgical oncologist’s standpoint, the soft tissues and skin margins are determined after
the extent of bony resection has been established. Our approach to reconstruction of these defects
essentially mirrors that of the ablationist: the algorithm is initiated once we have established which
specific walls of the maxilla are to be resected. The anterior (cheek), superior (orbital floor), and inferior
(palatal) walls most commonly need to be reconstructed for the following reasons. Bone replacement is
essential in the floor of the orbit to maintain position of the ocular globe. It is also useful in the maxillary
arch to provide anterior projection of the midface and bone stock for osseointegrated implants.Bone
grafts can be effectively used in conjunction with soft-tissue flaps (free or pedicled) for reconstruction of
the orbital floor, because this area requires minimal supportive strength. Vascularized bone is indicated
in the maxillary arch if osseointegration is required. Free flaps generally are indicated when skin islands
are necessary for intraoral cheek, palatal, nasal lining, or external resurfacing. The space between the
restored anterior, superior, and inferior walls of the maxilla can usually be filled with soft tissue
(muscle/fat), and nasal lining may or may not be necessarily restored. One of the most challenging
aspects of freeflap reconstruction of the midface is the long distance from midface to neck that needs to
be spanned for reliable donor vessels, particularly when the lower jaw is intact. The ideal free flap must
therefore have a 10- to 13-cm pedicle to reach the neck without vein grafting.In addition to long vessels,
the flap must provide critical ratios of bone, palatal lining/nasal lining, skin, and soft tissue and, most
importantly, must fit into the complicated three-dimensional shape of the defect. The two free flaps
most commonly used in this series (radial forearm and rectus abdominis) have large-diameter vessels
and their own distinctive characteristics with regard to the relative ratio of skin to soft-tissue bulk . The
radial forearm flap provides a large surface area of pliable skin with minimal soft tissue and can be
combined with a vascularized bone segment.The rectus flap, on the other hand, provides reliable skin
with much a larger volume of soft-tissue fill. Both flaps provide multiple skin islands that can be oriented
in different three-dimensional positions.Thus, the choice of flap is dictated by the volume of the defect
and skin surface area requirements.

2. Type I (limited maxillectomy)These resections usually include portions of the anterior/medial walls of
the maxilla and occasionally the orbital rim in combination with soft tissues and skin of the cheek . The
palate is never included .
These defects have small volume and large surface area requirementS
Options:
 critical segments of bone missing, such as the orbital rim or the anterior floor of the orbit,
nonvascularized bone grafts provide the needed support
 The radial forearm flap provides good external skin coverage and minimal bulk with multiple
skin islands that can be deepithelialized to improve contour, wrap around bone grafts, or supply
nasal lining

Type II Defects: Subtotal Maxillectomy
Type II: Subtotal Maxillectomy Defects
These defects include resection of the lower five walls of the maxilla, which include the palate
and dentoalveolar arch but leave the orbital floor intact.
Type IIA defects include less than 50% of the arch of the maxilla and do not extend past the
midline . Type IIB defects involve greater than 50% of the maxillary arch and extend past the
midline. Many of these defects can include bilateral maxillae and involve the entire arch

3. Type II A TYPE IIB

These reconstructions have medium volume and large surface-area requirements.
OPTIONS: The forearm flap when folded over provides ample skin to reline the palatal mucosal surface
as well as the nasal floor.
osteocutaneous sandwich flap: bone graft could be sandwiched separately between these two skin
surfaces.
Anterior (bilateral) subtotal maxillectomies(TYPE IIB)
total loss of support of the upper lip.
Option :sandwich flap
TYPE III: Total Maxillectomy Defects
These defects include resection of all six walls of the maxilla, including the floor of the orbit and
palate/alveolar arch, and may or may not include resection of the orbital contents.
Type IIIA defects involve resection of all six walls of the maxilla, including the floor of the orbit but
sparing the orbital contents Type IIIB defects involve resection of all six walls of the maxilla, including
exenteration of the orbital contents(The roof of the maxilla is the floor of the orbit. The floor of the
maxilla is the hard palate(base) The anterior, posterior, medial, and lateral walls are the vertical
buttresses, and the maxillary antrum is contained within the six walls of the bone) The vertical
buttresses consist of the paired nasomaxillary (NM), zygomaticomaxillary (ZM) and
pterygomaxillary (PM) midfacial buttresses .

4. IIIA IIIB
IIIA: These are medium-large volume and mediumlarge surface-area defects. The two functional
requirements that need to be addressed are support of the orbital contents (orbital floor
reconstruction) and reconstruction of the palate.
OPTIONS: ORBITAL FLOOR RECONSTRUCTION WITH NON VASCULARISED BONE GRAFTS
The bone graft must be sandwiched between a healthy flap (either rectus abdominis or temporalis)
below and the orbital contents above.
IIIB: These patients undergo resection of the entire maxilla in addition to exenteration of the orbit (also
known as the extended maxillectomy). These defects are extensive and have a large volume and large
surface-area requirement
AREAS NEEDING CLOSURE: The palate needs to be closed, the nasal lining (medial wall of maxilla) often
needs to be restored to maintain adequate airway, and the external defect is often extensive, involving
eyelids, cheek, and occasionally the lip. In addition, the anterior cranial base in the area of the sphenoid
is often exposed, and coverage of the brain becomes essential.
Options: If the external skin of the cheek is intact, a rectus free flap with a skin island used to close the
palate is a simple, straightforward solution. If the flap is not too bulky, a second skin island to restore the
lateral nasal wall can be used. A third skin island can be used to provide closure of the external skin
deficit if necessary
Type IV Defects: Orbitomaxillectomy These orbitomaxillectomy defects include the upper five walls of
the maxilla and the orbital contents. They are generally large volume/large surface-area defects (Fig. 4,
below). Because the palate is intact, reconstructive objectives consist primarily of soft-tissue fill and
external skin resurfacing if needed . The rectus abdominis flap effectively provides all these features.
These are conceptually simple reconstructive procedures, but the principal challenge is technical; one
needs to anastomose the flap to a donor vessel site in the neck, as temporal and facial vessels are
usually resected and unreliable