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Condylar Prostheses in Head and Neck Cancer Reconstruction
Alpen Patel, MD;
Robert Maisel, MD
Arch Otolaryngol Head Neck Surg. 2001;127:842-846.
ABSTRACT
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Objective To discuss the use of condylar prostheses after mandibular resection
for tumor.
Design Case series and literature review.
Setting Tertiary referral center.
Patients Four patients underwent condylar reconstruction with metallic condylar
prostheses after hemimandibulectomy for either squamous cell cancer or Ewing
sarcoma.
Main Outcome Measure Complications related to the condylar prostheses.
Results Clinical and radiological follow-up in these patients revealed several
complications, including exposure or extrusion of the prosthesis and migration
of the prosthesis into the epitympanum, resulting in profound sensorineural
hearing loss owing to bony destruction of the cochlea. Two of our patients
required removal of the mandibular hardware because of the seriousness of
the complications, and 1 of the 2 underwent reconstruction of the condyle
with a fibular free flap.
Conclusions Metallic condylar prostheses in the setting of tumor resection and reconstruction
involve significant risks. Autogenous materials, such as vascularized bone
grafts, should be used whenever possible.
INTRODUCTION
CONDYLAR replacements have been used for many years in cases of ankylosis,
severe degenerative diseases, tumors involving the condyle, osteomyelitis,
dysplasia, congenital malformation, and trauma. Reconstruction of the condyle
is performed to restore the joint as closely as possible to its normal position
and function.
Use of alloplastic materials to replace the condyle was first reported
by Gordon in 1955.1 Gordon's rationale for
using an alloplastic implant was to maintain functional mandibular ramus height,
to avoid malocclusion, and to prevent mandibular hypomobility. The general
opinion during the following years was consistent with Gordon's concept that
condylectomy without replacement would result in facial deformity, pain, and
limitation of movement.1 A variety of alloplastic
and autogenous materials were therefore advocated to replace the condyle.
These included silicone rubber (Silastic), Proplast, and polytef (Teflon).
Use of various metallic implants has also been reported, including the Christensen
implant and the titanium-coated hollow-screw reconstruction plate, or THORP,
system. Autogenous materials used for condylar replacement have included temporalis
muscle/fascia flaps, osteochondral rib grafts, and vascularized bone grafts.
Some of these materials have worked very well, especially in treatment of
temporomandibular joint (TMJ) disorders, but others have caused devastating
problems for patients. Reconstruction of the condyle after an ablative procedure
for cancer remains a surgical challenge.
The purpose of this article is to describe our experiences with metallic
condylar prostheses for reconstruction after tumor resection.
REPORT OF CASES
During the period of September 1989 to April 1995, metallic condylar
prostheses were placed in 4 male patients (mean age, 49 years). Three of the
4 patients underwent condylectomy and composite resection for retromolar trigone
squamous cell carcinoma. These patients also underwent a neck dissection and
pectoralis major myocutaneous flap to reconstruct the soft tissues in the
oral cavity/oropharynx. Also, they received preoperative (n = 1) or postoperative
radiotherapy (n = 2). The other patient underwent a hemimandibulectomy, including
resection of the condyle, for Ewing sarcoma. All 4 patients underwent immediate
condylar reconstruction with either a 2.7-mm hemimandibular reconstruction
plate (SYNTHES; AO/ASIF Foundation, Paoli, Pa) (n = 1) or a titanium reconstruction
bar with condylar attachment (Stryker Leibinger, Freiburg, Germany) (n = 3)
(Figure 1, Figure 2, and Figure 3).
Postoperatively and during follow-up, attention was given to any complications
resulting from surgery. The mean follow-up time was 23.3 months.
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Figure 1. A 2.7-mm titanium reconstruction
bar with condylar attachment. This prosthesis was used in reconstruction of
the condyle in 3 patients.
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Figure 2. Intraoperative view of a metallic
condylar prosthesis transferred to the mandibular defect.
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Figure 3. Posteroanterior radiograph of
a condylar prosthesis. The prosthesis is in the correct position in the glenoid
fossa.
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Our patients were diagnosed as having several complications from 5 to
37 months after surgery, including cross-bite deformity and malocclusion (n
= 1), infection (n = 2), and transient facial nerve paresis secondary to a
dislodged prosthesis (n = 1). One patient experienced migration of the prosthesis
into the epitympanum, resulting in otorrhea and profound sensorineural hearing
loss due to bony destruction of the cochlea (n = 1) (Figure 4). During removal of his prosthesis, histopathologic evaluation
of a middle ear mass revealed a granuloma reaction. The 3 patients who received
radiation therapy had exposure or extrusion of the prosthesis Figure 5). Despite conservative management with observation and
local wound care for 1 year, 1 patient required removal of the exposed mandibular
hardware and had successful reconstruction of the condyle with a fibular free
flap.
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Figure 4. An axial computed tomogram of
the temporal bones shows extension of a prosthesis into the epitympanum, abutting
the ossicular chain. Also, bony destruction exists medially from the epitympanum
to the cochlea.
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Figure 5. Patient with exposed bar 5 months
after placement.
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COMMENT
A wide range of condylar prostheses are commercially available. The
Christensen prosthesis, which has been in use for more than 25 years, comprises
a metal fossa and a metal condyle with an articulating dome of polymethylmethacrylate.
It has been shown to be effective in treating patients with severe TMJ disorders,
resulting in significantly reduced pain and improved function in 85% to 90%
of patients.2 However, the use of polymethylmethacrylate
can result in more fibrosis, sometimes with reactive cartilage, neo-ossification,
or heterotopic and reactive bone formation.3
Recently approved by the Food and Drug Administration, a custom-made
total joint prosthesis (TMJ Concepts [formerly Techmedica], Camarillo, Calif)
can be manufactured according to the patient's specific anatomical and morphological
characteristics. The device has worked very well for TMJ reconstruction in
56 patients, with significant improvement relative to pain, occlusal stability,
and function.3 However, to our knowledge, no
studies to date have investigated the usefulness of this device in patients
with tumors.
Using the THORP system, Raveh et al4
reported successful condylar reconstruction in 2 patients: one underwent a
hemimandibulectomy and irradiation for treatment of osteosarcoma 10 years
previously; the other had an untreated fracture 5 years previously that resulted
in ankylosis. Follow-up examination showed unimpaired occlusion, correct function
and guidance of the joint, and no lateral deviation during opening.4 The major advantages of the THORP system are the stable
anchorage of the carrier plate to the mandible by hollow screws and the 3-dimensional
adaptability of the condylar prosthesis after fixation of the plate to the
mandible. These features allow the condyle to articulate with the glenoid
fossa and to reproduce the normal rotational and translational movements of
the condyle.5 With the THORP system, the advent
of osteointegrating screws that lock to the reconstruction plate appears to
have significantly reduced the risk of loosening hardware.6
The THORP system led to the development of the locking reconstruction plate/screw
system. This system simplifies the locking mechanism between the plate and
screw, eliminating the need for expansion screws.
Development of new alloplastic implants (eg, the THORP system) that
provide long-term rigid fixation by the process of osseointegration has led
to a renewed interest in the application of mandibular plates for the rehabilitation
of patients with head and neck tumors. Kim and Donoff7
used AO plates to reconstruct the mandibular condyle and ramus after malignant
tumor ablative surgery (n = 13). Only 1 patient required revision or plate
removal because of infection. Other experiences with attempted condylar reconstruction
using metallic implants have been disappointing. In 1 series (n = 5), the
use of titanium mandibular reconstruction plates after excision of advanced
malignant tumors resulted in a moderately high failure rate. As in our study,
the majority of plate losses occurred in patients who had undergone irradiation.8 In another series, 2 plates were removed totally or
partially owing to extrusion in 4 patients who underwent hemimandibulectomy
with disarticulation of the TMJ and immediate reconstruction with titanium
AO plates.9 Lindqvist et al10
performed 23 TMJ arthroplasties using metallic condylar prostheses, including
9 for segmental mandibular resections in tumor surgery. A clinical and radiological
follow-up study showed heterotopic bone formation in 52% of cases and glenoid
fossa resorption in 43%. In 1 patient, the condyle eroded through the skull
base 10 months after surgery. Thirty percent of prostheses were removed and/or
replaced during the average 27.6-month follow-up.10
Other authors have also reported glenoid fossa resorption with displacement
of the prosthesis in the middle cranial fossa.11
Alloplastic condylar prostheses may fragment or mechanically break down,
resulting in production of implant debris in the joint. A foreign body response
directed against this debris contributes to heterotopic bone formation and
progressive bony degeneration. Proplast, polytef, and Silastic implants are
known to cause a severe foreign body giant cell reaction, bone and soft tissue
destruction, reactive bone, and migration of microparticulate debris to other
body areas, initiating or exacerbating connective tissue and autoimmune disease
problems.3 These processes can produce symptoms
of pain, alteration in occlusion, and mandibular hypomobility. Magnetic resonance
imaging is useful in detection and evaluation of destructive complications
that may accompany failed Proplast and polytef implants.12
Because these implants are associated with unfavorable outcomes, they are
no longer indicated for condylar reconstruction.
In summary, possible complications of condylar reconstructive surgery
using alloplastic implants include the following: temporary or permanent facial
nerve weakness; middle ear infections; temporary or permanent hearing loss;
tinnitus; dysequilibrium; malocclusion; infection; exposure or extrusion of
the prosthesis; development of adhesions or ankylosis within the joint space,
causing trismus; displacement, fragmentation, and/or loosening of prosthetic
components; heterotopic bone formation; bony erosion of the skull base, with
herniation of the implant into the middle cranial fossa; foreign body reaction;
and rejection of the implant.13
In agreement with our results, plate exposure is the most common cause
of reconstructive failure in patients who undergo placement of condylar prostheses
after mandibular resection for tumor. An increased incidence of plate exposure
has been noted to occur in those patients who require extensive soft tissue
resection or radiation therapy. While the pectoralis myocutaneous flap has
been the most widely used method of soft tissue reconstruction in this setting,
the long-term effect of gravity on the flap pedicle, combined with the opposing
action of jaw motion, may increase the risk for wound dehiscence and plate
exposure. External plate exposure in lateral mandibulectomy defects may also
result from wound contracture that results from the dead space that is normally
occupied by bone medial to the reconstruction plate. The process results in
medialization of the overlying skin and eventual pressure necrosis. This concept
is supported by the observation that external plate exposure is not usually
seen in patients in whom mandibular reconstruction plates are used for rigid
fixation of vascularized bone grafts.6
Radiation therapy may play an important role in plate exposure. However,
most patients who undergo treatment of advanced carcinomas that require hemimandibulectomy
will require combined therapy that includes radiotherapy.6
There is a higher incidence of wound dehiscence and revision of plates in
patients who have undergone irradiation than in those who have not undergone
irradiation.9 Some authors have expressed concern
about using postoperative radiation therapy in patients with titanium plates,
as the plates might create hot spots that could contribute to breakdown of
the overlying skin and eventual exposure of the prosthesis.14
Use of any alloplastic material to replace the condyle may be inadvisable
given our experiences and those of others. Several biologic reasons speak
for autogenous transplant, and there seem to be few reasons for abolishing
this concept.10 Removal of implant, joint debridement,
and placement of pedicled temporalis muscle/fascia flap to line the glenoid
fossa have been shown to be effective in controlling pain and improving jaw
motion in patients with failed alloplastic TMJ implants.1
The temporalis muscle flap can also be brought down to provide a soft tissue
bed in which the delicate cartilaginous cap of a osteochondral rib graft can
function. The nonvascularized osteochondral graft has proved to be a significant
advance in reconstruction of the condyle in children, particularly in those
with acquired deformities.15
Autologous grafts, especially free bone grafts, such as the osteochondral
rib graft, are often susceptible to unpredictable resorption. For this reason,
vascularized bone grafts are being used more widely for mandibular reconstruction.
Vascularized bone is also resistant to infection and extrusion, and it can
survive in a poor recipient bed resulting from prior irradiation. Various
types of such grafts are described in the literature, but the most satisfactory
results, both aesthetic and functional, have been achieved with the use of
the iliac crest and fibular free flaps.15-16
Rivas et al16 used iliac crest or fibula vascularized
bone grafts in 7 patients to reconstruct condylar defects due to resection
for oral neoplasm. They reported minimal donor site morbidity and good functional
results. According to Urken et al,17 the internal
oblique–iliac crest osseomyocutaneous free flap is most ideal for mandibular
reconstruction, especially as its natural shape simulates that of the patient's
mandible, thereby reducing the contouring of the neomandible. Criticism of
free flap reconstruction of the mandible has focused on the additional operative
time required to perform microvascular tissue transfer, as well as on the
donor site morbidity that results from harvest of bone-containing flaps. However,
the use of the vascularized bone graft for condylar reconstruction after jaw
resection for malignant disease has been reliable, with minimal long-term
morbidity thus far.15, 17 Nevertheless,
the role of the vascularized bone graft needs to be better established in
the treatment of condylar defects after ablative tumor surgery.
Many surgeons delay bony reconstruction of the mandible until overlying
soft tissue satisfactorily heals and the patient is free of recurrent disease.
However, wound contraction, fibrosis, and oftentimes radiation distort tissues
and make delayed reconstruction difficult.14
Facial nerve injury is also more likely.6 Furthermore,
because many patients with advanced tumors of the head and neck have a poor
prognosis, it is important to achieve immediate reconstruction, allowing patients
a rapid functional and aesthetic recovery. Immediate mandibular reconstruction
at the time of ablative surgery also provides patients with less change in
appearance and self-esteem, which in turn improves the likelihood of the resumption
of normal social activities.14 One study showed
no significant difference in the failure rate between immediate reconstruction
and delayed reconstruction of the condyle using AO plates.7
Further research is essential in determining any benefit from delayed
reconstruction of the condyle after tumor resection and in seeking alternative
prosthetic replacements, especially in patients who are medically or surgically
unsuitable for vascularized bone reconstruction.
CONCLUSIONS
Metallic condylar prostheses in the setting of tumor resection and reconstruction
involve significant risks and potential complications, and they do not give
a satisfactory result. Autogenous materials, such as the vascularized bone
graft, should be used whenever possible.
AUTHOR INFORMATION
Accepted for publication April 5, 2001.
Presented as a poster at the annual meeting of the American Head and
Neck Society, Fifth International Conference on Head and Neck Cancer, San
Francisco, Calif, July 29-August 2, 2000.
Corresponding author: Robert Maisel, MD, Department of Otolaryngology,
University of Minnesota, Box 396, Mayo Bldg, 420 Delaware St SE, Minneapolis,
MN 55455.
From the Department of Otolaryngology, University of Minnesota, Minneapolis.
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