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Biomedical subjects

M G Rock

Publications and source records attributed to M G Rock.

61 records · Page 4Linked to original sources
PubMed1984

Extra-abdominal desmoid tumors.

One hundred and ninety-four patients with extra-abdominal desmoid tumors, most of them in the extremities, have been treated at the Mayo Clinic. One hundred and thirty-two patients (68 per cent) experienced a recurrence at an average of 1.4 years after the first treatment. A greater tendency for recurrence was evident in female patients, in patients who were more than thirty years old, in certain anatomical locations (especially the foot and calf), and most importantly after treatment by intralesional or marginal excision. In view of the excellent prognosis for survival, we recommend wide local excision when anatomically feasible or marginal excision and postoperative radiation therapy when function of the extremity would be severely compromised if excision with wide margins were done. A recurrent lesion that does not appear to be growing should be followed until evidence of growth of the lesion precipitates a secondary wide excision.

Adolescent↗
PubMed1984

Metastases from histologically benign giant-cell tumor of bone.

Metastasis from a giant-cell tumor of bone that is histologically benign has become a recognized entity. To date, thirty-one pathologically proved cases have been reported in the world literature. To this, we add eight cases from our experience of more than 400 cases of histologically benign giant-cell tumor of bone. The lungs are the principal site of metastasis, the lesions being pathologically indistinguishable from the primary tumor. The metastatic process is unpredictable as to clinical aggressiveness, and the mortality rate is approximately 25 per cent. We advise aggressive attempts at complete extirpation of metastases.

Adolescent↗
PubMedDate not supplied

Distal upper extremity function following proximal humeral resection and reconstruction for tumors: contralateral comparison.

BACKGROUND: Most functional analyses after limb salvage operations about the shoulder have focused on proximal function with the assumption that distal function is largely unaffected. This analysis examines distal function objectively. METHODS: Objective laboratory data regarding distal upper extremity strength after reconstructive procedures for tumors near the shoulder joint was collected over a 16-year period. Thirty-two patients were able to participate fully in the data collection at an average most recent follow-up duration of > 3.5 years. RESULTS: Statistically significant reductions on the involved side compared with the uninvolved side in grip, forearm pronation, forearm supination, elbow flexion, and elbow extension strength were documented (p < 0.05). The magnitude of reduction in strength diminishes distally, with the greatest effect in this group of patients being observed in elbow extension, followed by elbow flexion, forearm supination, and forearm pronation. Grip strength consistently showed the least amount of strength reduction compared with the uninvolved side, even within resection and reconstruction groups. Subjective patient rating of dexterity was no less than 3 of 5. Ninety percent of patients rated their dexterity 4 of 5 (52%) or 5 of 5 (38%). CONCLUSIONS: Despite the insistence of "normal" function in the distal upper extremity after limb salvage procedures, complete normality is not maintained. However, the degree of maintenance of distal function appears to be high, especially for grip strength and forearm pronation strength, and patient satisfaction is acceptable.

Adolescent↗
PubMedDate not supplied

Infection after rotator cuff repair.

Sixteen patients (15 men and 1 woman) were treated for infection complicating rotator cuff repair during the period 1975 through 1994. Eight of the 16 patients had their initial procedure performed elsewhere. The remaining 8 procedures were performed at our institution with the known incidence of this complication being 0.27%. In addition to intravenous antibiotic therapy, an average of 3.5 (range 2 to 8) operative procedures were required to eradicate the infections. Micro-organisms cultured were Propionibacter in 6, coagulase negative Staphylococcus in 4, Staphylococcus aureus in 4, Peptostreptococcus magnus in 1, and both Propionibacter and coagulase-negative Staphylococcus in 1. The deltoid was restored in all patients; the rotator cuff was reparable in 11. In the 12 shoulders with greater than 1 year of follow-up (average 51 months, range 14 to 165 months), active elevation averaged 110 degrees and external rotation 50 degrees. Four patients had no pain, 4 had minimal pain, and the remaining 4 had moderate pain. Satisfactory final results, which were determined by the patients' opinion or with the use of either the University of California, Los Angeles score or the modified Neer system, were obtained in 5 (42%) of the shoulders.

Adult↗
PubMedDate not supplied

Analysis of periprosthetic tissue formation around a porous titanium endoprosthesis using CT-based spatial reconstruction.

OBJECTIVE: Reformatted CT-based image data may be of use in evaluation of new bone formation around massive bone replacement implants, but the impact of metal-induced artifacts on the accuracy of image reconstruction is unknown. This study was designed to evaluate the accuracy and precision of quantitative image reconstruction in the presence of a titanium implant. MATERIALS AND METHODS: Model porous-coated titanium implants were harvested from 23 dogs 12 weeks after surgical implantation. Contiguous 1.5 mm transverse CT scans were done first with the titanium implant in place, then repeated after replacement of the implant with an acrylic spacer. Microradiographs of sections cut at defined locations were used to establish gray level thresholds for image reconstruction and to validate the accuracy of CT-based image data. Reformatted image data were used to determine periprosthetic bone volume (mm3) and area of interfacial contact between bone and implant (mm2). RESULTS: The CT-based data derived with either implant material had an accuracy of 83-88% and a precision coefficient of variation (CV) of 2-4% for both volume and contact area variables. Presence of titanium did not seriously affect the quality of images obtained, and results were strongly correlated with those obtained with acrylic. CONCLUSION: Accurate volumetric data derived from CT-based images of periprosthetic new bone formation can be obtained in the presence of a titanium endoprosthesis. Improved demonstration of spatial relationships of bone and implant may improve postoperative evaluation.

Animals↗
PubMedDate not supplied

Unilateral facet dislocation of the cervical spine. An analysis of the results of treatment in 26 patients.

Twenty-six patients with unilateral facet dislocation of the cervical spine were analyzed to determine the best method of treatment of this injury, the incidence of late pain and instability, and the indications for surgical stabilization. This review showed that all patients with a unilateral facet dislocation of the cervical spine should be treated initially with halo traction in an attempt to obtain reduction. If reduction is obtained, then nonoperative treatment in the form of a halo thoracic apparatus may be the best method of treatment. Failure to obtain reduction with axial traction is an indication for open reduction and one-level posterior cervical fusion. Patients left in the displaced position and allowed to heal in that position usually develop late pain as a complication of this method of treatment.

Adult↗