Biomedical subjects

S R Cannon

Publications and source records attributed to S R Cannon.

At least 19 recordsLinked to original sources

PubMed1990

Parosteal osteosarcoma. Treatment by wide resection and prosthetic replacement.

We have reviewed 20 cases of parosteal osteosarcoma treated by wide local resection and prosthetic replacement and followed up for six to 17 years. Limb function was excellent in 85%. One patient with grade III histological disease developed pulmonary metastases. Four patients had local recurrences, which were related to repeated preliminary biopsies, inappropriate siting of biopsy and vascular encroachment by the tumour. After this mode of treatment, the outcome was not related to medullary invasion by the tumour.

Adolescent↗

PubMed1988

Inadequacy of the Gorlin formula for predicting prosthetic valve area.

A total of 135 patients with normally functioning prosthetic aortic valves who were catheterized 6 months after placement of Hancock, modified Hancock or Bjork-Shiley prostheses were studied to determine the magnitude of error in Gorlin formula estimates of prosthetic aortic valve area. All patients were male, selected from 13 participating hospitals and routinely followed after valve replacement for 5 years. Hemodynamically determined Gorlin valve areas were compared with independently verified actual valve areas. Actual Hancock areas were measured from videotapes of valves exercised in a pulse duplicator flow model. Actual Bjork-Shiley areas were calculated directly from the valves' inner ring radius. Gorlin valve areas correlated poorly with actual valve areas (r = 0.39). The mean Gorlin formula error was 0.36 cm2 (standard deviation = 0.32). Gorlin areas overestimated actual areas by greater than 0.25 cm2 in 43 patients (32%) and underestimated actual areas by greater than 0.25 cm2 in 29 (21%). It was concluded that the Gorlin formula inaccurately predicts prosthetic valve area in the aortic position. Overreliance on this formula in assessing aortic stenosis could lead to errant clinical decisions.

Aortic Valve↗

PubMed1988

Pseudomembranous colitis associated with antibiotic prophylaxis in orthopaedic surgery.

We report 16 orthopaedic patients who had antibiotic-associated diarrhoea (pseudomembranous colitis) after operation. There was an association with the use of cephradine and with the prolongation of prophylaxis for more than three peri-operative doses. Five cases occurred as a cluster, suggesting that the causative agent, Clostridium difficile, may be infectious in some situations.

Adult↗

PubMed1988

Malignant fibrous histiocytoma: the most common soft-tissue sarcoma.

Although soft-tissue sarcomas account for less than 1% of all malignancies, over 55 different histological variants have been described. Consequently clinicians often find the classification both complex and confusing. A new variant, the malignant fibrous histiocytoma (MFH), is now the most common adult soft-tissue sarcoma, therefore a clear understanding of the diagnosis, its implications and the optimum treatment is desirable.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1987

The Colonna-Hey Groves arthroplasty in the late treatment of congenital dislocation of the hip. A long-term review.

Forty-four patients who had undergone 50 capsular arthroplasties for congenital dislocation of the hip were reviewed after a mean follow-up of 20 years. Their average age at operation was 5.9 years; 31 of the operations were undertaken because of late presentation, the remainder because of the failure of previous surgery. In all, 70% of the hips showed good function despite a reduced range of movement, but patients with bilateral arthroplasties fared poorly. Excellent containment within the acetabulum was found in 80%, but the femoral head was always abnormally high though not unduly lateral or medial. This configuration had remained unchanged during follow-up. The accuracy of reduction along the mediolateral axis was the only variable found to influence the outcome significantly. Functional deterioration, associated with pain, was noted to be more common after 20 years than before, and was associated with radiographic evidence of joint degeneration.

Child↗

PubMed1986

Breakdancer's back.

We report a case of a painful soft tissue swelling in the thoracolumbar region of the spine of a breakdancer, which caused serious diagnostic difficulty because of coexisting congenital absence of a transverse process of the first lumbar vertebra.

Back Pain↗

PubMed1986

A long-term study following Bennett's fracture.

Twenty-five patients with documented Bennett's Fractures were reviewed five to sixteen years following injury (Mean 9.6 years). The majority of fractures affected the dominant hand and occurred in males. Twenty-two patients were managed conservatively by plaster immobilisation. At review ten patients were asymptomatic and only two had significant symptoms. Examination revealed loss of movement in the trapeziometacarpal joint of the thumb in twenty-one cases. Five of these exhibited malrotation of the thumb. Review of the post reduction radiographs revealed separation of the fragments by 1 mm or more in sixteen patients, but symptoms at follow-up could not be correlated with accuracy of reduction. Twenty-three patients had a varus angulation of the first metacarpal base which could be correlated to the initial post-reduction displacement. There was no correlation with the restriction of movement. Although metacarpal length will only be maintained by reduction of the fracture, there was little evidence that imperfect reduction leads to significant symptomatic arthritis in the long term.

Adolescent↗

PubMed1986

Calculation of aortic valve area by Doppler echocardiography: a direct application of the continuity equation.

The continuity equation suggests that a ratio of velocities at two different cardiac valves is inversely proportional to the ratio of cross-sectional areas of the valves. To determine whether a ratio of mitral/aortic valve orifice velocities is useful in determining aortic valve area in patients with aortic stenosis, 10 control subjects and 22 patients with predominant aortic stenosis were examined by Doppler echocardiography. The ratio of (mean diastolic mitral velocity)/(mean systolic aortic velocity), (Vm)/(Va), and the ratio of (mitral diastolic velocity-time integral)/(aortic systolic velocity-time integral), (VTm)/(VTa), were determined from Doppler spectral recordings. Aortic valve area determined at catheterization by the Gorlin equation was the standard of reference. High-quality Doppler recordings were obtained in 30 of 32 subjects (94%). Catheterization documented valve areas of 0.5 to 2.6 (mean 1.1) cm2. There was good correlation between Doppler-determined (Vm)/(Va) and Gorlin valve area (r = .90, SEE = 0.23 cm2); a better correlation was noted between (VTm)/(VTa) and Gorlin valve area (r = .93, SEE = 0.18 cm2). The data demonstrate the usefulness of Doppler alone in the determination of aortic valve area in adults with absent or mild aortic or mitral regurgitation and no mitral stenosis. Although the use of mean velocity and velocity-time integral ratios requires accurate measurement of mitral and aortic velocities, it does not require squaring of these velocities or measurement of the cross-sectional area of flow.

Adult↗

PubMed1986

Massive osteolysis. A review of seven cases.

Seven cases of massive osteolysis are presented. The aetiology of this disease is as yet unknown; neither age nor sex seems to be a factor in its incidence, nor are standard bone grafts or radiotherapy successful methods of treatment. However, in this series, operation produced a satisfactory outcome for five patients at a mean follow-up of 17 years; in three of these patients a custom-built prosthesis was inserted, and in one a conventional bone graft was combined with intramedullary nailing.

Adolescent↗

PubMed1986

Recurrent dislocation of the hip with a "Bankart-type" lesion.

A patient with recurrent dislocation of the hip is described. The initial injury had been a posterior dislocation without associated fracture of the acetabular wall, and the hip had not been immobilised or protected from weight-bearing during treatment. Exploration of the hip for recurrence revealed disruption of the posterosuperior acetabular labrum with formation of a pouch between the posterior acetabular wall and the short rotator muscles. We have found no previous report of this lesion, which resembles a Bankart lesion of the shoulder. Repair using a bone block is described.

Adult↗

PubMed1985

Multiple chondrosarcomas in dyschondroplasia (Ollier's disease).

The relationship between dyschondroplasia (Ollier's Disease) and the possibility of malignant change is well known. The authors describe a patient who developed four primary chondrosarcomas over 11 years. These were treated by local wide excision and, in two sites, prosthetic replacement to preserve the limb. To the authors' knowledge, no patient with more than two primary chondrosarcomas has previously been described.

Adult↗

PubMed1985

Simple external fixation of open and complicated fractures.

Thirty patients were managed with the use of a simple means of external fixation. Ten of these patients had multiple injuries. In 18 the fractures were open. Five cases had loss of bone length and infected wounds when first seen and were treated with the aid of microvascular surgical procedures. Eight cases required skin grafting. One case required a vein graft to the popliteal artery. The method described is simple to use. It requires little previous experience and is cost effective. We recommend its use in the initial treatment of grade 2 and 3 open fractures. It may also be used on closed unstable fractures, and will maintain limb length in severe injuries with loss of bone substance while further treatment is considered or performed.

Bone Screws↗

PubMed1985

Comparison of Doppler echocardiographic peak frequency and turbulence parameters in the quantification of aortic stenosis in a pulsatile flow model.

To test the relative accuracy of Doppler echocardiographic peak frequency and turbulence parameters in assessing aortic stenosis, we constructed a pulsatile flow model that simulated human left ventricular and aortic pressures, flow, and anatomy. Continuous wave-measured peak frequencies and pulsed Doppler-measured turbulence were determined in the model ascending aorta for nine stenotic valve areas for each of five different flow rates. The mean squared systolic peak frequency (MSPF) and turbulence spectral envelope area (SEA) were regressed against the mean systolic gradient (r = .94, SEE = 5.6 mm Hg; and r = .96, SEE = 1.2 mm Hg, respectively). SEA was more accurate than MSPF at moderate-to-high degrees of stenosis and exhibited a smaller standard error. MSPF was more accurate than SEA in mild stenoses, where SEA tended to overestimate gradients. When flow data were included in a multiple regression analysis, both MSPF and SEA provided fair predictions of actual effective valve areas (r = .90 and r = .94, respectively). Use of high pulse-repetition-frequency Doppler echocardiography significantly reduced aliasing problems common to pulsed Doppler techniques.

Aortic Valve Stenosis↗

PubMed1985

Hydraulic estimation of stenotic orifice area: a correction of the Gorlin formula.

To determine the source of errors in the Gorlin formula for estimating stenotic valvular orifice area, we used a pulsatile flow model that emulated left ventricular and aortic pressures and flow and allowed control of ventricular outflow orifice area. After comparing orifice areas calculated by the Gorlin formula with actual orifice areas, the Gorlin formula constant (k) was found to be highly correlated with the square root of the mean transvalvular gradient (r = .95). A new formula was derived empirically and predicted areas more accurately and with smaller standard errors than the Gorlin formula in the model (r = .98, SEE = 0.11 and r = .87, SEE = 0.28, respectively) in a series of 19 patients with Hancock porcine xenograft valves (r = .89, SEE = 0.07 and r = .60, SEE = 0.12, respectively) and in the original series of patients reported by Gorlin and Gorlin in proposing the Gorlin formula (r = .93, SEE = 0.11 and r = .91, SEE = 0.12, respectively).

Aortic Valve Stenosis↗

PubMed1984

Back pain in athletes.

There were one hundred and ninety seven patients who presented with back pain to an Athletes Clinic over four years. Their mode of presentation, investigations, diagnoses and treatments are analysed. The majority of patients were male and below 30 years of age. The average duration of symptoms prior to presentation, despite an easy access policy, was 42 weeks. Injury was usually related to six popular sports. Radiological examination was a rewarding investigation in these patients and included an A-P view of the pelvis. The diagnostic label of prolapsed intervertebral disc appears to have been used too frequently. Physiotherapy was the most useful treatment modality regardless of age, mode of onset and duration of symptoms.

Adolescent↗

PubMed1983

Noninvasive diagnosis of aortic and mitral valve disease with pulsed-Doppler spectral analysis.

To differentiate normal from abnormal left-sided heart valves, 34 adults (6 normal and 28 abnormal) with 48 valve lesions proved at catheterization were examined using a 3 MHz duplex pulsed Doppler echocardiograph with 2-dimensional verification of sample volume position and on-line display of the Doppler audio spectrum. A uniform protocol was used to position the sample volume for each lesion and to analyze the Doppler spectral data. Intracardiac blood turbulence, manifested by an increased Doppler spectral envelope area, was the noninvasive indicator of disease. The specific lesion present was determined by documenting the intracardiac location and timing of the turbulence. Doppler spectral envelope areas in all normal valve sites were smaller than those measured at the same sites in patients with aortic stenosis, mitral stenosis, and mitral regurgitation (p less than 0.01). Except for a single patient with minimal aortic regurgitation, spectral envelope area allowed complete separation of patients with valve disease from normal subjects (p less than 0.01). High sensitivity (97%) and specificity (100%) were noted despite the presence of multiple valve lesions in 67% of the patients. The data demonstrate application of a simple, noninvasive method of acquiring and analyzing Doppler echocardiographic data which allows accurate identification or exclusion of left-sided valve disease in adults, even in the presence of multiple valve lesions.

Adult↗

PubMed1983

Traumatic separation of the proximal femoral epiphysis and fracture of the mid-shaft of the ipsilateral femur in a child. A case report and review of the literature.

A case is described of traumatic separation of the proximal femoral epiphysis associated with a fracture of the mid-shaft of the same femur in a two-year-old girl. The rarity of this injury is emphasized and its treatment outlined. No similar reports could be found, and the relevant literature is reviewed.

Child, Preschool↗

PubMed1982

Digital Fourier techniques in the diagnosis and quantification of aortic stenosis with pulsed-Doppler echocardiography.

Pulsed Doppler echocardiography and digital Fourier analysis were utilized to examine flow distal to the aortic valve and to quantify aortic stenosis. A graphic index of parameters derived from velocity spectrum patterns generated by Fourier analysis was regressed against mean systolic pressure gradients in 21 adults with clinical evidence of aortic stenosis who underwent catheterization studies and five normal adults (r = .82). Correlation improved in the absence of regurgitation (r = .92). Sensitivity for detecting gradients greater than 30 mmHg was 86%; specificity was 90%. Doppler spectral analysis shows promise in alleviating the need for many invasive studies.

Aortic Valve Stenosis↗