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Biomedical subjects

R F Morgan

Publications and source records attributed to R F Morgan.

At least 73 records · Page 4Linked to original sources
PubMed1989

Lidocaine permeability in silicone tissue expanders: an in vitro analysis.

Tissue expansion has achieved a prominent role in soft-tissue reconstruction. Expansion-induced pain is often a limiting factor in this process and can affect patients for as long as 24 to 48 hours following each expansion session. Although lidocaine is known to be an effective analgesic, only anecdotal reports of its usefulness when placed within a tissue expander currently exist. This two-part study was designed first to determine if in fact silicone is readily permeable to lidocaine, and second to determine if the potential diffusion dynamics can be defined. In part 1 of the study, the silicone polymer was indeed found to be readily permeable to lidocaine as measured with fluorescence immunoassay technique. In part 2, two groups of Surgitek and Dow Corning expanders were filled with saline and lidocaine and placed in saline baths. At several intervals over a 48-hour period, aliquots of the surrounding saline were sampled and the lidocaine levels subsequently determined. A rather predictable and consistent diffusion curve was demonstrated. The significant difference in diffusion characteristics between the two expander types was apparently due to wall thickness differences inherent in the manufacturing. In this in vitro study, filler-valve leakage did not significantly contribute to lidocaine migration from within these tissue expanders. This basic in vitro work will now set the stage for further in vivo and clinical investigations to more precisely define the role of lidocaine in the tissue-expansion process.

Lidocaine↗
PubMed1989

Nerve compression syndromes of the lower extremity.

Nerve compression syndromes of the lower extremity present a challenge in differential diagnosis. Compression of the common peroneal nerve occurs relatively frequently; compression of the sciatic nerve occurs infrequently. The pattern of weakness helps distinguish lumbar root entrapment from peripheral compression syndromes. Compression syndromes must also be differentiated from diabetic, alcoholic or vasculitic neuropathy. Recovery correlates with the degree and duration of nerve injury. Thus, early diagnosis and treatment are important.

Diagnosis, Differential↗
PubMed1988

In defense of the concept of biological aging measurement--current status.

Biological age is the objective assessment of a person's health status. Theoretically, a 'normal' person's biological age--in terms of appearance, performance, and functional capacity--should be the same as his chronological age. Many scientists have attempted to develop systems to accurately determine individuals' biological age. Typically, the approach is to select a battery of test parameters comprised of tests which correlate closely with chronological age. This approach assumes that those traits which vary most closely with age are the best indicators of the aging process. The goal has been to compare an individual to his chronological age peers to determine his relative aging status. Two papers (Costa and McCrae, 1980 and 1985) that criticize this concept and approach have heretofore gone unanswered. Lack of published dissent has caused many gerontologists to assume that Costa and McCrae are correct in their assertions that biological age cannot be measured and is not a valid concept. Consequently, some scientists have been reluctant to pursue research in this area. The purposes of this paper are: to critically evaluate the questions raised by Costa and McCrae; to reaffirm the validity of the concept of biological age; and to urge continued research in this most important subject.

Aged↗
PubMed1988

Seroma prevention using fibrin glue during modified radical neck dissection in a rat model.

Seroma is a frequent sequelae of neck dissection involving cervical lymphadenectomy. The incidence is correlated with flap elevation, lymphovascular interruption, and tissue removal. Current methods of resolving seroma, such as vacuum drainage, are not risk free. A novel approach to this problem was the use of intraoperative topical fibrin glue. A model producing seromas was developed by modified radical neck dissection on Sprague-Dawley rats. Forty rats underwent this procedure. Twenty rats were treated with saline solution (control group) and 20 were treated with fibrin glue. At necropsy on day 5, a significant reduction in the frequency of seroma was noted in the fibrin glue group. Seventeen of 20 control rats had seroma whereas only 2 of 20 experimental animals had serous collection. The Fisher exact statistical correlation revealed p less than 0.000002; therefore, the use of fibrin glue in this role merits further evaluation.

Animals↗
PubMed1988

Principles of emergency wound management.

Every traumatic wound treated in the emergency department is a result of a finite energy source that caused tissue disruption. The dynamics of this exchange of energy will determine the magnitude of injury. Disruption of the body covering leaves the once-sterile underlying integument exposed to contamination. The contaminants are derived from either the victim (endogenous) or the exogenous energy source. The presence of a contaminant such as bacteria makes the care of the wound an exercise in microbiology. Other contaminants, such as dirt, also may reside in the recesses of the wound. Emergency physicians must understand the consequences of tissue trauma. A study of the mechanism of injury will provide a reliable indication of damages. Whether the tissue injury will be limited to the initial wounding depends on the outcome of the interaction between the contaminants and the wound. In the event that the contaminants are very reactive, a relatively insignificant wound may become a catastrophe. This circumstance can be averted by the implementation of a well-devised plan based on the biology of wound healing and infection.

Anti-Bacterial Agents↗
PubMed1988

Reconstruction of full thickness chest wall defects.

Over the last 5 years, 14 patients were treated by wide en bloc resection of chest wall tumors with primary reconstruction. There were nine females and five male patients with an age range of 31-77 years. All patients had a skeletal resection of the chest wall. An average of 3.9 ribs were resected in the patients treated. In three patients a partial sternectomy was carried out in conjunction with the rib resections. Chest wall skeletal defects were reconstructed with Prolene mesh, which was placed under tension. Soft tissue reconstruction utilized selected portions of the latissimus dorsi musculocutaneous territory with fasciocutaneous extensions beyond the muscle itself. Primary healing was obtained in all patients and secondary procedures were not required. The average hospitalization was 23 days. All patients survived the resection and reconstruction and were alive 30 days after operation. In selected patients the preservation of a portion of the innervated muscle in situ or the transfer of the muscle with the preservation of its resting length has maintained the majority of the muscle function.

Adult↗
PubMed1988

Automatic wire twister.

This automatic wire twister used in surgery consists of a 6-inch needle holder attached to a twisting mechanism. The major advantage of this device is that it twists wires significantly more rapidly than the conventional manual techniques. Testing has found that the ultimate force required to disrupt the wires twisted by either the automatic wire twister or manual techniques did not differ significantly and was directly related to the number of twists. The automatic wire twister reduces the time needed for wire twisting without altering the security of the twisted wire.

Bone Wires↗
PubMed1988

Recurrent skin infections: a diagnostic enigma.

Our 25 years of experience with treating patients with recurrent skin infections has resulted in a rational plan that usually solves this diagnostic enigma. Our evaluation consists of a comprehensive examination of the infected tissue, as well as a search for systemic factors and diseases that interfere with host defenses and/or the biology of wound repair. Patient assessment begins with a detailed history, a search for foreign bodies in the wound, as well as histologic and microbiologic examinations of the infected tissue. Clinical recognition and laboratory evaluation for metabolic and endocrinologic dysfunction, a deficiency of the immune system, protein-calorie malnutrition, or a specific defect in collagen synthesis are other integral components of our diagnostic plan for patients with recurrent skin infections.

Antibody Formation↗
PubMed1988

Large disposable trephines for circular excision biopsy of the skin.

Large disposable circular trephines have been developed specially for circular excision biopsy of the skin. This technique is a simple and practical alternative to the traditional method of excision. It has the advantages of aligning the incision in the direction of the maximum skin tensions and reducing the length of the final wound closure.

Biopsy↗
PubMed1987

Effects of lidocaine concentration on distal capillary blood flow in a rabbit ear model.

The laser pulse doppler provides a noninvasive, reproducible method to measure the flux in distal capillary blood flow in a rabbit ear model. The distal capillary blood flow responds proportionally to changes in periarterial lidocaine concentration. The response is biphasic. Flow initially decreased from the baseline in all lidocaine concentrations between 0.5% and 10.0%. Proportional increases in distal blood flow above baseline are noted as the buffered lidocaine concentrations increase from 1.0% to 10.0%. Lidocaine concentration of 0.5% dose not increase distal blood flow above baseline.

Animals↗
PubMed1987

Performance of disposable needle syringe systems for local anesthesia.

The performance of different disposable needle syringe systems was determined by measuring needle-puncture pain, needle-bending forces, and the fluid dynamics of the systems. Thirty-gauge needles cause less needle-puncture pain than any other needle. The force required to bend the 30-gauge needle irreversibly was lower than that for the other needles. Studies of the fluid dynamics of different needle syringe assemblies demonstrated that the flow rate can be limited by using large-size syringes (30 mL) and needles with the smallest internal diameter. On the basis of the results of this study, 30-gauge needles attached to 10-mL syringes are recommended for infiltration anesthesia, and 25-gauge needles with 10-mL syringes are advocated for regional nerve blocks. In infiltration anesthesia, the local anesthetic agent should be injected slowly into the subdermal tissue over a 10-second period. When performing regional nerve blocks, it is also advisable to inject the local anesthetic agent over a 10-second time interval.

Anesthesia, Local↗
PubMed1987

Late rupture of the flexor tendons as a complication of replacement arthroplasty.

A case of attritional rupture of the flexor tendons secondary to metacarpophalangeal (MP) replacement arthroplasty for treatment of rheumatoid arthritis is reported. This complication is thought to be the result of resection of the palmar plate during the arthroplasty that was performed 5 1/4 years previously. Although not previously reported, it could be an expected late result if the palmar plate is excised during arthroplasty.

Adult↗
PubMed1987

Recognizing the temporomandibular joint ganglion.

A case report of a cystic preauricular mass that changed in size and position with jaw movement is presented. This tumor proved to be a ganglion of the temporomandibular joint (TM) cyst, which is relatively rare. When a preauricular mass retrudes into the masseter muscle in jaw opening, pathological conditions associated with the TMJ should be considered. Ganglion cysts of the TMJ are a benign pathological entity which can mimic parotid tumors. Temporomandibular joint radiography and perhaps ultrasonography of the region are useful in the preoperative evaluation of preauricular masses. The TMJ ganglion cyst can be successfully treated by direct excision and repair of the joint capsule. This approach avoids the potential morbidity of a superficial parotidectomy.

Female↗
PubMed1987

Pelvic recurrence of rectal cancer. Options for curative resection.

Pelvic recurrence is an ominous event after curative resection of rectal cancer and is rarely amenable to re-resection by conventional methods. A method to permit a composite resection of these using the abdominal sacral approach has been described previously. This report updates that experience with resection of pelvic recurrence of rectal cancer in 28 patients. Of these, 24 were done with curative intent, and four were done for palliation (mainly for infected or fungating tumor). All patients had extensive preoperative evaluation by clinical and radiologic tests, and most patients had a long free interval period of approximately 18 months, after their primary resection. Although 47 patients had exploratory surgery, only 29 had local disease amenable to resection and four had palliative resections. About half the patients had had an abdominoperineal resection, half had had an anterior resection, and one third had had previous efforts to resect the recurrence. All but one patient had been irradiated with 3000-11,000 cGy. All but two patients (of the 24 curative efforts) required a formal abdominosacral resection (through S1-2 in 12, S2-3 in 9, and S4-5 in 1). Over half the patients also required a bladder resection. There were three operative deaths (12%); one patient had a cardiac death immediately after operation and two were septic deaths at 35 and 60 days. The survivors generally had relief of sacral root pain and good motor function; most of those previously employed could return to work. The actuarial 5-year survival rate is 25% and median survival is 36 months. Long-term survival over 48 months was recorded in five of 21 surgical survivors (23.8%). Survival in a historic comparative group of 30 patients treated for local recurrence only (mainly by radiation) was 15 months median, and at 5 years the survival rate was 3% (p less than 0.001). In conclusion, selected patients with pelvic recurrence of rectal cancer may be retrieved by and returned to functional life with the composite abdominosacral resection.

Abdomen↗
PubMed1987

The omentum as an untapped reservoir for microvascular conduits.

The use of the omentum as a source for vessel grafts is recommended when long or multiple vessel conduits are needed and when a combination of vessel grafts and soft tissue are needed. It is particularly suitable in reconstructing the superficial palmar arch but may also provide an immense graft reserve for the imaginative and careful surgeon.

Blood Vessel Prosthesis↗
PubMed1987

Pediatric burns.

Burns are the second most common cause of death in childhood. More than half of pediatric burns are partial-thickness scald burns; the majority occur in the kitchen. Generally, minor burns may be treated on an outpatient basis, while moderate burns are treated in a community hospital. Children with major burns should be transferred to a regional burn unit as soon as possible after stabilization, provision of fluids and, if necessary, intubation.

Age Factors↗