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Biomedical subjects

K P Schellhas

Publications and source records attributed to K P Schellhas.

At least 37 records · Page 2Linked to original sources
PubMed1991

Magnetic resonance imaging of the temporomandibular joint: preliminary evaluation of partial flip angle three-dimensional volume acquisitions against conventional single and multiecho pulse sequences.

The authors imaged 20 temporomandibular joints (TMJs) in 20 patients with high field surface coil magnetic resonance imaging, to compare the accuracy and the clinical utility of thin section partial flip angle (PFA) three dimensional (3D) volume acquisitions with T1-weighted images (T1WI), spin echo, multiecho, long TR/short and long TE images, PFA gradient recalled acquisition in the steady state (GRASS) images in the diagnosis of internal derangement of the TMJ. Pathological conditions demonstrated on imaging studies included disk derangement, joint effusion, and osteocartilaginous lesions, such as degenerative arthritis, osteoporosis, osteochondritis dissecans and early avascular necrosis of the mandibular condyle.

Humans↗
PubMed1990

Facial skeleton remodeling due to temporomandibular joint degeneration: an imaging study of 100 patients.

One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.

Adolescent↗
PubMed1990

Facial skeleton remodeling due to temporomandibular joint degeneration: an imaging study of 100 patients.

One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.

Adolescent↗
PubMed1989

Facial pain, headache, and temporomandibular joint inflammation.

We studied one hundred patients with suspected temporomandibular joint (TMJ) arthropathy in whom 64 also complained of headache and/or facial pain, using high field surface coil magnetic resonance (MR) imaging, and found that headache and facial pain are commonly observed in association with inflammatory arthropathy of the TMJ. Each patient complained of pain and/or tenderness localized to the immediate vicinity of at least one TMJ. Pathologic joint effusion was demonstrated by MR in 88 of the painful joints studied. Significant meniscus displacement, with or without meniscus deformity and alteration of intrinsic signal intensity was present in 94 of the 100 painful joints examined. Fascial inflammation and atrophy of the ipsilateral muscles of mastication were observed occasionally with painful joints. There were no mechanical TMJ symptoms, such as joint clicking, crepitus or locking in 14 internally deranged and painful joints, 12 of which exhibited joint effusion and local inflammation. At least 80 patients described occlusal changes within 12 months of imaging. 28 of the pathologic joints in the series underwent subsequent meniscectomy, including routine histologic evaluation of surgical material. We conclude that internal derangement and inflammation of the TMJ should be considered in patients with unexplained headache and/or facial pain, even if mechanical TMJ symptoms are absent.

Adolescent↗
PubMed1989

Temporomandibular joint injuries.

The clinical and radiologic findings in 30 patients who sustained injuries to the temporomandibular joint (TMJ) were retrospectively analyzed. Imaging consisted of variable combinations of radiography, tomography, two-compartment arthrography, computed tomography, and magnetic resonance imaging and was performed 2 days to 24 months after injury. Indications for imaging included acquired and/or unstable occlusal disturbances, cephalalgia, facial pain, otalgia, TMJ pain, tinnitus, dizziness, hearing disturbance, masticatory dysfunction, and muscle atrophy. Radiologic findings included internal derangement of the TMJ meniscus, swelling of retrodiskal tissues, joint effusion, mandibular condyle and condylar neck fractures, osteochondritis dissecans, avascular necrosis, degenerative condylar remodeling, osteoarthritis, musculotendinous injuries, and atrophy of masticatory muscles. After imaging studies, seven patients underwent surgery, at which time imaging findings were confirmed; one patient underwent successful aspiration of a painful hemarthrosis. TMJ injuries may result in joint derangement, radiologically demonstrable joint degeneration, masticatory muscle dysfunction, pain, and progressive clinical disability.

Adolescent↗
PubMed1989

Clinical vs. arthrographic diagnosis of TMJ internal derangement.

Internal derangements of the temporomandibular joint (TMJ) have gained increased recognition as a potential source of pain and dysfunction of the masticatory system. The objective of this study was to evaluate the reliability of clinicians in predicting an arthrographic diagnosis of articular disc position in a typical patient population presenting for TMJ arthrographic evaluation. Two clinicians utilized a brief history, clinical examination (including evaluation of mandibular movement and TMJ auscultation), and tomographic TMJ imaging in evaluating 60 patients. The radiologist subsequently performed the arthrographic procedures on 102 TMJs (18 unilateral and 42 bilateral). Diagnostic agreement was determined for all possible diagnostic categories including: normal disc position, TMJ internal derangement with reduction, TMJ internal derangement without reduction/acute, TMJ internal derangement without reduction/chronic, and osteoarthrosis. The significance of the diagnostic agreement between the clinicians and arthrography was evaluated with a Kappa Statistical Test, which showed good reliability. For epidemiological studies, it was concluded that clinical and tomographic evaluation would provide sufficient reliability for determination of the presence and stage of TMJ internal derangement. However, in a specific clinical situation, a difficult diagnostic problem may require the use of arthrography, depending on the impact of the diagnosis on subsequent treatment decisions.

Adolescent↗
PubMed1989

MR of osteochondritis dissecans and avascular necrosis of the mandibular condyle.

We studied 40 patients exhibiting radiologic changes of either osteochondritis dissecans (OCD) or avascular necrosis (AVN) involving the mandibular condyle to evaluate the structural changes associated with these lesions when using high-field-strength MR imaging. Various clinical indications for imaging each patient with routine radiography, tomography, and surface-coil MR included headache, temporomandibular joint (TMJ) and/or ilsilateral facial pain, joint crepitus, clicking, locking, and either recently acquired or changing (unstable) occlusal disorder. Radiologic findings included alterations in condyle morphology and MR signal characteristics compatible with either OCD or AVN or, in some cases, both. Previous nonsurgical mandibular trauma was temporally related to the onset of symptoms in eight patients. Five patients exhibiting either unilateral or bilateral AVN involving the condyles and condylar necks had undergone previous orthognathic surgery, including sagittal split mandibular osteotomies followed by intermaxillary fixation. One patient exhibiting condylar AVN with articular surface collapse and osseous destruction had undergone previous TMJ meniscectomy followed by insertion of a permanent Proplast implant. Thirty-one of 34 patients with no prior surgery and MR changes of condylar OCD/AVN had associated internal derangement of the TMJ meniscus. There was surgical confirmation of findings in 10 joints. We assert that OCD and AVN are relatively common, clinically significant lesions of the mandibular condyle often associated with preexisting internal derangement of the temporomandibular joint.

Adolescent↗
PubMed1989

Temporomandibular joint inflammation: comparison of MR fast scanning with T1- and T2-weighted imaging techniques.

One hundred painful temporomandibular joints in 100 patients were studied with high-field, surface-coil MR imaging. Partial flip angle or GRASS (gradient-recalled acquisition in steady state) and either T1-weighted or spin-echo long TR/short-long TE imaging techniques were used to assess the relative sensitivity and accuracy of these techniques in detecting joint fluid. Intraarticular fluid, interpreted to represent joint effusion, was observed in 88 of the 100 painful joints scanned. GRASS scans were obtained with the mouth closed, partially opened, and fully opened; T1-weighted and spin-echo images were obtained only with the mouth closed. Long TR/long TE spin-echo images were the most sensitive to fluid detection within the joint spaces. GRASS images were highly sensitive to intraarticular fluid, although the thicker scan section and local artifacts associated with these techniques resulted in lower accuracy compared with the spin-echo long TR/long TE images. Joint fluid was directly observed in many of the 28 joints operated on from the series, and two of two joints were successfully aspirated. Osteochondritis dissecans and avascular necrosis are best demonstrated and staged with a combination of short TR/short TE and long TR/long TE weighted images, although a spin-echo long TR/short and long TE pulse sequence is more practical for this purpose. We recommend long TR/short and long TE spin-echo closed-mouth sagittal images combined with GRASS closed- and open-mouth views whenever inflammatory temporomandibular joint disease is suspected.

Adolescent↗
PubMed1989

MR imaging of muscles of mastication.

High-field MR imaging was used to study structural and physiologic alterations involving the muscles of mastication in 46 patients. Muscular abnormalities were often detected incidentally in conjunction with lesions of the CNS, cranial nerves, facial bones, and/or temporomandibular joint (TMJ). Specific pathologic alterations observed included anomalies of musculoskeletal development, muscle hypertrophy, atrophy (disuse and denervation), inflammatory disorders, injuries (including contusions, tears, and muscle rupture), posttraumatic musculoskeletal deformities, and reflex sympathetic dystrophy. Atrophy, fatty replacement, fibrosis, and contracture of selected muscles of mastication may accompany internal derangement of the TMJ in the absence of traumatic deformity. We conclude that MR is a highly accurate imaging method for detecting masticatory muscle disease. Nontraumatic anatomic and physiologic abnormalities of the muscles of mastication are uncommon disorders. Demonstrable muscle alterations frequently accompany fracture dislocations of the mandibular condyle neck and related facial bones onto which masticatory muscles attach.

Adolescent↗
PubMed1988

Three-dimensional computed tomography in maxillofacial surgical planning.

Fifty-four maxillofacial three-dimensional computed tomographic examinations were performed during a 12-month period for the purpose of surgical planning. Pathologic entities in the series included trauma, neoplasia, cleft palate, and other developmental anomalies. Computer-assisted mandibular disarticulation was performed routinely after each study to permit direct viewing of the mandible or maxilla in isolation. Three-dimensional computed tomography is a useful technique for maxillofacial surgical planning.

Adolescent↗
PubMed1988

Temporomandibular joint: MR imaging of internal derangements and postoperative changes.

Nineteen abnormal temporomandibular joints (TMJs) imaged with high-field-strength surface-coil MR are presented to illustrate specific changes associated with disk derangement, trauma, and previous surgery. Cases were selected from a series of 248 TMJ MR studies in 144 patients (9-68 year old, 130 females and 14 males) performed during a 5-month period. Surgical findings were available for correlation in 44 of the 248 joints studied. Increased signal caused by myxoid degeneration within the degenerating meniscus was seen, as were pathologic changes including atrophy, fibrosis, and contracture of masticatory muscles occurring with internal derangements. Advantages and limitations of MR are discussed with reference to arthrography and videofluoroscopy. High-resolution and partial-flip-angle images of a normal joint are provided for comparison. In most clinical circumstances, MR is the procedure of choice when examining the TMJ, because it provides contrast resolution of soft-tissue structures superior to that of conventional imaging techniques.

Female↗
PubMed1988

The diagnosis of temporomandibular joint disease: two-compartment arthrography and MR.

The reliability and accuracy of two-compartment temporomandibular joint (TMJ) arthrography was compared with MR imaging on the basis of an analysis of surgical findings obtained from joints that had been studied preoperatively with arthrography or MR or, in some cases, both procedures. Seven hundred forty-three consecutive TMJ arthrograms were successfully obtained in a total of 443 patients by using a single 27-gauge needle and a two-compartment technique in each joint. There was a 100% correlation with surgical findings in 218 radiologically abnormal joints operated on within 90 days of arthrography with respect to the presence or degree of meniscus displacement and normal or abnormal disk morphology and function. In 604 patients 1052 TMJs were studied with high-field-strength surface-coil MR. Surgical findings were available for correlation in 170 of the joints studied. Forty-three joints were studied with both two-compartment arthrography and MR. Eight operated joints had been imaged successfully with both two-compartment arthrography and MR. Both methods of evaluation provided highly reliable and accurate information regarding meniscus position and shape. Arthrography was superior to MR in detecting capsular adhesions and the presence or absence of perforation of the disk or meniscus attachments. Simple meniscectomy (with or without insertion of a temporary Silastic TMJ implant) was the most frequently performed surgical procedure in the series, followed by meniscus repositioning procedures. Joint effusions, failed TMJ implants, and avascular necrosis were demonstrated best with MR. Soft-tissue lesions, including intrinsic degeneration of the meniscus, anomalous muscle development, muscle atrophy, tendinitis, and injuries such as contusions and hematomas, were demonstrated only with MR. Partial-flip-angle GRASS (gradient-recalled acquisition in the steady state) techniques permit both fast scanning and study of functional joint dynamic. Joint fluid may appear as high signal intensity on GRASS images because of T2*-weighting. We recommend MR as the procedure of choice for diagnosis of uncomplicated internal derangements of the TMJ. Two-compartment arthrography with videofluoroscopy is an important ancillary procedure that should be performed whenever capsular adhesions or perforations are suspected and not demonstrated with MR and whenever MR is inconclusive.

Arthrography↗
PubMed1988

Permanent Proplast temporomandibular joint implants: MR imaging of destructive complications.

We studied the radiologic and pathologic changes in 30 patients (34 joints) in which there were locally destructive bone and soft-tissue complications associated with previously inserted permanent temporomandibular joint (TMJ) Proplast-Teflon implants. The cases were selected as representative examples of patients with failed Proplast interpositional arthroplasty, in whom images of the TMJ were obtained with conventional radiography, tomography, and MR, and in whom both surgical and histologic findings were available. Clinical indications for imaging included joint pain, restricted joint motion, crepitus, preauricular swelling, regional lymphadenopathy, malocclusion either acquired or changed since implant surgery, and facial deformity. Surgery was then performed for the purposes of implant retrieval and joint debridement because of destructive soft-tissue and osseous changes observed from the imaging analysis in conjunction with significant clinical signs and symptoms. The pathologic changes, observed 4-54 months after implant surgery, included a destructive foreign-body-type granuloma and avascular necrosis of the mandibular condyle and condylar neck. Our findings suggest that MR is useful in the detection and evaluation of destructive complications that may accompany failed Proplast-Teflon implants in the TMJ. MR is superior to conventional radiography and tomography in detecting soft-tissue lesions and avascular necrosis of bone. Tomography more accurately delineates soft-tissue calcifications and cortical margins of osseous structures.

Adult↗