Учебники / Color atlas of temporomandibular joint surgery Quinn
.PDF
2 0 4 |
Color Atlas of Temporomandibular Joint Surgery |
FIG. 7 . 4 4
A
A, Christensen all-metal condylar prosthesis articulating with Christensen fossa. Both components ore made of Vitallium. B, A panorex x-ray film showing all-metal Christensen prosthesis in position. C, Posterior-anterior skull film of an all-metal Christensen condyle articulating with Vitallium Christensen glenoid fossa.
B
c
Chapter Seven Autogenous and Alloplastic Reconstruction of the Temporomandibular Joint |
2 0 5 |
FIG. 7 . 45
A B
A, A 31-year-old woman who underwent bilateral total joint replacement with all-metal Christensen prostheses after several unsuccessful arthroplasties. The inlerincisional opening is 32 mm, with a marked reduction of presurgical pain level B, Anterior-posterior skull view of all-metal Christensen prosthesis.
FIGS . 7 . 4 6, 7 . 47
Custom-made Christensen condylar and fossa prostheses. These prostheses are fabricated from a Cad-Cam plastic model produced from CT data. This provides an excellent way to create a stable joint prosthesis in patients who have distorted anatomy and who have undergone multiple operations.
Custom Techmedica prosthesis positioned on Cad-Cam model generated from CT data.
2 0 6
A
FIG. 7 . 4 8
B
c
Postoperative x-ray images of Techmedica total joints. A, Lateral view. B, Frontal view. C, Panorex.
With any total joint alloplastic system the patient is capable of only rotational motion because no lateral pterygoid insertion exists to provide protrusive movement. Between 32 and 35 mm of intraincisal opening is a reasonable expectation for range of motion with a total joint prosthesis. Unilateral replacement causes deviation to the side of the prosthesis on terminal opening. Pain reduction for patients who have undergone multiple operations is also a reasonable expectation; a direct correlation exists between the number of previous surgical procedures and the likelihood that presurgical symptoms will be reduced. At this point, no longterm data have been compiled on the subject of currently available alloplastic implant systems. Orthopedic experience suggests that these implants systems may have a useful life span of approximately 7 to 10 years. With advances in both biomaterials and clinical understanding of necessary design modifications, this figure should increase. Complications that are specific to alloplastic joints include the following: prosthesis displacement or fracture, foreign-body reaction to polymeric or metallic debris, heterotopic bone formation (which causes ankylosis of the prosthesis), and damage to the inferior alveolar nerve by screw placement. The facial nerve can be damaged during placement of the prosthesis, but this risk is inherent in all joint procedures. This author is currently involved in a clinical trial
Chapter Seven |
Autogenous and Alloplastic Reconstruction of the Temporomandibular joint |
2 0 7 |
Endotec joint —condyle and fossa.
FIG. 7 . 49
Endotec condyle component showing the "antimicromovement" locking screw. Two screws are in place, and the third screw is off to the side, with the locking screw above the regular screw. The locking screw inserts in the large hole in the prosthesis.
FIG. 7 . 50
of a prosthesis developed by Biomer-I.orenz. The prosthesis is composed of a high- molecular-weight polyethylene fossa that is secured to the zygomatic arch by four self-tapping 2.0-mm screws. The fossa prosthesis is a stock prosthesis, and the articular eminence surface is flattened before fitting begins. A clear Lucite template is used to achieve a tripod effect, imparting stability to the fossa prosthesis. Once the prosthesis is stable, a small amount of methacrylate cement is used to fill the voids between the fossa prosthesis and the glenoid fossa. The cement should never
2 0 8 |
Color Atlas of Temporomandibular joint Surgery |
be used as a load-bearing surface. It is mechanically locked to the fossa with a small dowel projecting from the inner surface of the fossa. The methyl methacrylate is cured outside the body to avoid any excessive heat against the glenoid fossa. Once the fossa is fitted, the patient is placed in intermaxillary fixation and the chrome-cobalt condylar prosthesis is fitted. The components are designed to optimize contact between the condyle and the fossa. The point of rotation is moved inferiorly, and the deep concavity in the glenoid fossa is designed to allow for pseudotranslation of the condylar prosthesis during opening. This design modification has improved the maximum intraincisal opening by approximately 15% to 1 8 % . Early results are very encouraging but far from conclusive at this stage.
Experienced surgeons can achieve satisfactory results with autogenous reconstruction or alloplastic reconstruction of the temporomandibular joint. Costochondral grafting is clearly the procedure of choice in growing patients, but a predictably successful, safe, and effective alloplastic prosthesis offers great advantages for reconstruction of the severely altered joint in adult patients. When sound data confirm the effectiveness of an available model or one that is yet to be developed, surgeons will have a choice between equally effective autogenous and alloplastic techniques. The ultimate decision will be based on the particular needs of the patient.
FIG. 7 . 5 1
Biomet-Lorenz temporomandibular joint prosthesis. The fossa is high-molecular-weight polyethylene that is secured to the zygomatic arch with 2.0-mm screws. The Vitallium condylar prosthesis is designed to optimize the noting between the condylar and fossa components.
Chapter Seven |
Autogenous and Alloplastic Reconstruction of the Temporomandibular joint |
2 0 9 |
FIG. 7 . 52
A B
A, Biomet-Lorenz prosthesis placed in a cadaver to show the shielding effect of the polyethylene fossa, which protects against ankylosis from heterotopic bone formation. Also, note that since the polyethylene can be no thinner than 4 mm, the point of rotation (condylion) is moved inferiorly. B, Note the thickness of the polyethylene fossa and the presence of o dowel on the fossa surface. The polyethylene fossa is fit initially so that it has a tripod stability on bone with the polyethylene alone. Orthopedic methyl melhacrylote cement, used as nonloading filler, has been dyed brown in this example to show the demarcation between the components.
A
A, B, Biomet-Lorenz prosthesis in a cadaver depicting passive translation of condyle in the glenoid fossa prosthesis. Note that the condyle tends to glide anteriorly within the fossa during translation, which tends to increase the range of motion approximately 15% to 18%.
FIG. 7 . 53
B
2 1 0 |
Color Atlas of Temporomandibular Joint Surgery |
FIG. 7 . 5 4
A B
A, Biomet-Lorenz prosthesis in position. B, Fossa prosthesis with the dowel of methyl methacrylate cement, which is cured outside the body and trimmed with a #15 blade before conplete setting. This ensures that the load-bearing contact against bone is with polyethylene and not with the cement, which is simply used to fill the voids.
FIG. 7 . 5 5
A panorex x-ray film showing a Biomet-Lorenz prosthesis in position. Care is taken to note the position of the inferior alveolar artery and nerve during placement of the screws for the condylar prosthesis. When placing the anterior row of screws, the surgeon should drill through the buccal cortex only initially. This precaution allows the surgeon to abandon that site if brisk bleeding occurs.
Chapter Seven |
Autogenous and Alloplastic Reconstruction of the Temporomandibular Joint |
2 1 1 |
FIG. 7 . 56
A B
A, Excellent view of the condylar prosthesis through a modified posterior mandibular incision. Five or six self-tapping 2.7-mm screws are used to secure the prosthesis to the lateral ramus. B, A panorex film shows the angulation of the condylar neck and the convex surface of the condylar head.
A
FIG. 7.57
B
A, A 22-yeor-old woman who underwent multiple joint surgeries before joint reconstruction with custommade titanium Biomet-Lorenz prostheses. These were selected because of a documented sensitivity to nickel. B, Postoperative anterior-posterior skull view of same patient.
P A T H O L O G Y O F C H A P T E R E I G H T
T H E T E M P O R O M A N D I B U L A R
J O I N T
Benign and malignant tumors can affect the structures of the temporomandibular joint. Although tumors are rare compared with disorders of internal derangement and osteoarthritis, the surgeon must always be on the alert for signs of neoplasia. Space-occupying lesions of the joint may present with preauricular swelling, pain, trismus, limitation of opening, and malocclusion. If clinical and radiographic examinations suggest the presence of a tumor, arthroscopic biopsy or open arthrotomy is most helpful. All the various tissues of the temporomandibular joint can serve as a nidus for tumor formation. Tumors and lesions affecting the
temporomandibular joint include the following:
BENIGN TUMORS AND LESIONS |
MALIGNANT TUMORS |
Osteoma |
Osteogenic sarcoma |
Osteochondroma |
Chondrosarcoma |
Chondroma |
Synovial cell sarcoma |
Chondroblastoma |
Synovial fibrosarcoma |
Giant cell granuloma |
Multiple myeloma |
Giant cell tumor |
Lymphoma |
Neurofibroma |
Aggressive fibromatosis |
Hemangioma |
|
Arteriovenous malformation |
|
Synovial chondromatosis |
|
Osteochondrosis dissecans |
|
Villonodular synovitis |
|
Ganglion cyst |
|
If the initial biopsy shows the joint lesion is benign, it may be approached with a standard arthroplasty. For example, central giant cell granulomas have been known to affect the head of the condyle. They typically appear as solitary, radiolucent lesions of the mandible or maxilla. These lesions tend to involve the jaws anterior to the molar teeth, but they occasionally involve the mandibular ramus and condyle. They usually produce a painless expansion; however, when a spaceoccupying lesion affects the mandibular condyle, it causes a malocclusion and sometimes a preauricular swelling. Biopsy reveals a stroma of spindle-shaped fibroblasts in the presence of multinucleated giant cells. In the body of the mandible or maxilla, curettage followed by peripheral ostectomy is an acceptable initial approach. When the lesion completely destroys the condylar head, a standard condylectomy can be performed before immediate reconstruction with either
autogenous tissues (costochondral graft) or an alloplastic prosthesis.
Text continued on p. 218
213
2 1 4 |
Color Alias of Temporomandibular Joint Surgery |
FIG. 8 . 1
A B
c |
D |
E
A, Giant cell tumor of left temporomandibular joint on axial and coronal CT scans. Note almost complete destruction of condylar head to a level approximately 1 cm below the sigmoid notch. B, Axial CT depicting giant cell granuloma of left condylar head. C, Extended modified Risdon incision for wide access to ramus-condyle complex. D, Surgical specimen showing excision of condylar head and portion of coronoid notch for removal of giant cell granuloma. E, Lateral skull film depicting Christensen prosthesis in position.