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Biomedical subjects

R K Daniel

Publications and source records attributed to R K Daniel.

At least 55 records · Page 3Linked to original sources
PubMed1984

The efficacy of free tissue transfer in the treatment of osteomyelitis.

We evaluated the efficacy of free tissue transfer in the treatment of osteomyelitis in thirty-three patients who were followed for an average of 41.4 months (range, twenty-four to fifty-nine months). The bone lesions were classified in two ways: first, according to whether there had been drainage for less or more than six months and second, according to whether the lesion was Type I, II, or III. The thirty-three patients underwent a total of thirty-seven free tissue transfers, and thirty (79 per cent) of the transfers survived. Major complications were encountered after 41 per cent of the surgical procedures, consisting of failure of the free tissue transfer in seven patients (21 per cent) and recurrent sepsis in six (20 per cent) at follow-up. Four of the seven patients in whom the free tissue transfer failed underwent an amputation. Six of the patients with a failed transfer and nine of the ten with recurrent sepsis had a Type-III lesion. Previously published reports have suggested that free tissue transfer is an extremely successful and reliable procedure for the treatment of osteomyelitis. In our series limited success was achieved in patients with a Type-I or II lesion, but six of the patients with a Type-III lesion had recurrence of infection despite a successful transfer.

Adolescent↗
PubMed1983

Depressed scars and soft tissues.

The authors describe a technique that brings great improvement to the treatment of depressed scars. It is simple and safe as long as enough superficial tissue is available. Unequal peripheral undermining allows closure under minimal tension, is less extensive than in previously described techniques, and separates the deep scar from the superficial one.

Abdomen↗
PubMed1983

Monitoring acute skin-flap failure.

Reliable and repeatable means for the objective postoperative monitoring of skin flaps is a necessity. If a failing free flap can be recognized early, it can be salvaged by revision of the appropriate anastomoses. For the threatened distal portion of a conventional flap, external factors, such as kinking or hematoma, may be corrected or drug therapy instituted. We have analyzed blood from stab wounds in experimental pig flaps for pO2, pCO2, pH, and hematocrit. The results were compared with fluorescein penetration and flap surface temperature. The most significant finding was hematocrit readings of threatened flaps (54 percent) elevated above those of control flaps (35 percent). pH readings in the jeopardized flaps were 0.4 units below control. These two measures proved to be more reliable than intermittent temperature readings. In contrast to the fluorescein test, which can be used only once, stab wound analysis is repeatable at any time in the postoperative period. It can be effectively used to follow dynamic changes within a skin flap.

Animals↗
PubMed1983

Breast reconstruction following mastectomy.

Breast reconstruction now is an integral and valuable part of the management of patients with breast cancer. It offers hope and restitution for the patient while lessening the ablation and psychologic trauma of mastectomy. Continued close cooperation between the general surgeon and the plastic surgeon will assist the patient in her return as a functioning member of society and not mere survival as a mastectomy cripple.

Adult↗
PubMed1983

Vascularized bone autografts. Experience with 41 cases.

Forty-one autogenous vascularized bone grafts have been performed by the authors since 1976. Twenty-two free vascularized fibular grafts were performed in a lower extremity and ten in an upper extremity. Ten of these patients were treated for locally aggressive, benign, or low-grade malignant bone tumors, while the remainder of the patients were treated for massive trauma-derived, segmental bone defects. The average length of the bone defect was 14.9 cm for tumor cases and 16.2 cm for trauma cases. In four patients (12.5%), the operation was unsuccessful, resulting in amputation. Nine patients were treated by osteocutaneous groin flaps, with one failure, resulting in amputation. Vascularized autogenous bone grafts transferred by microvascular anastomoses have been found an effective method of treatment for massive segmental bone defects.

Adult↗
PubMed1983

Use of free vascularized bone grafts in the treatment of bone tumors.

A five-year experience with ten cases of primary resection of aggressive bone lesions treated by immediate reconstruction with autologous fibula demonstrates the advantages of vascularized, compared with free bone, graft. The procedure was performed for locally aggressive bone tumors in seven cases, and for Type III congenital pseudarthroses of the tibia in three cases. In large intercalary bone grafts, the vascularized fibula actively participates in the healing process, rather than serving merely as a framework for inductive creeping substitution, as is the case in conventional bone grafts. With the exception of one case, the grafts united and progressively hypertrophied, and there was no tumor recurrence. For defects less than 6 cm in diameter, conventional bone grafts usually prove successful. However, for defects greater than 6 cm or in a poorly vascularized bed, the vascularized fibular graft can prevent such complications as fatigue fracture, failure of incorporation, and nonunion that are frequently seen with nonvascularized cortical and cancellous bone grafts.

Adolescent↗
PubMed1982

Free tissue transfers for upper extremity reconstruction.

This study is a functional analysis of 18 free tissue transfers with a 1-to 4-year follow-up including: Six free skin flaps, two neurovascular free flaps, four free fibula, one free muscle, and three toe-to-thumb transfers. All tranfers survived except for one partial slough. Free skin-flaps allow single-stage skin coverage, a permanent blood supply, earlier secondary surgery, and potential sensory reinnervation. Free fibula transfer for long bone defects offer more rapid healing and incorporation in unfavorable recipient beds than do conventional grafts. Toe-to-thumb transfers have proven extremely valuable for thumb reconstruction, especially following multiple digit loss.

Adolescent↗
PubMed1982

Muscle coverage of pressure points--the role of myocutaneous flaps.

Although myocutaneous flaps have evolved into a primary method for managing pressure sores, their value in reducing the recurrence rate by padding the pressure point is open to question. The use of muscle to cover a pressure point violates the normal soft-tissue coverage of a bony prominence and introduces a tissue that is exquisitely sensitive to ischemia. Clinical follow-up of patients who have had myocutaneous flaps for closure of pressure sores demonstrates almost total muscle atrophy. Although skin coverage is stable, the muscle bulk of a myocutaneous flap is not retained beyond one to two years. The long-term value of myocutaneous flaps in reducing the recurrence rate of pressure sores requires careful follow-up in major series of cases.

Adult↗
PubMed1982

The omnipotential pig buttock flap.

An experimental pig flap model is presented with detailed operative technique. Studies employing this model are reported showing that difference in survival patterns depends on vascular configuration. Innervated island flaps were found to survive to the same length as denervated free flaps, and the onset of the benefits of the delay procedure occurred by the fourth postoperative day. The advantages of the pig and the pig buttock flap are discussed in detail.

Animals↗
PubMed1982

Pharmacologic treatment of the failing skin flap.

Pigs with random skin flaps were treated with phenoxybenzamine, isoxsuprine, or reserpine. No significant increase in flap survival was detected. In selected animals, cutaneous blood flow was measured using the microsphere technique. Of the drugs tested, reserpine was the only one to cause a significant increase in cutaneous blood flow. Previous clinical and experimental studies on the treatment of failing skin flaps are reviewed. The important criteria for designing future pharmacologic studies are discussed.

Animals↗
PubMed1981

Management of severe forearm injuries.

A review of principles and an operative guideline for repair of severely mutilating injuries to the forearm have been set forth. These concepts and their application have been illustrated in a series of clinical cases. The following key concepts have developed from these clinical experiences: 1. The surgeon must evaluate each case based upon the potential for return of sensation and function. One cannot justify the statement that a replanted arm is always superior to a prosthesis, even if its only purpose is cosmetic. 2. Care must be taken in the emergency room to evaluate the entire patient, and not to ignore other injuries while concentrating on a mangled extremity. 3. The crush-avulsion nature of injuries seen in a large referral center necessitates aggressive debridement of damaged soft tissue and bone. Wounds that have avulsion of skin, muscle, and nerve throughout the length of the arm do not lend themselves to repair. Destruction of an elbow joint generally precludes repair. 4. A well stabilized skeleton is essential before definitive soft tissue repairs can be performed. 5. Vascular repairs are meticulously performed using magnification. All vessels are reconstructed in an effort to recreate the original anatomy. 6. Wide destruction of muscle and tendon is frequent necessitating ingenuity in connecting proximal motor units to distal tendon. After repair, early active motion of the extremity is emphasized. 7. Perhaps the strongest contraindication to reconstruction of a severely damaged upper limb is avulsion of the nerves throughout the length of the forearm. Sharply divided nerves can be repaired by group fascicular suture. Crushed, divided nerves do well with accurate epineural approximation. Crushed nerves with epineural continuity ar best treated by observation and secondary grafting as required. 8. Primary coverage of areas denuded of skin is by split graft of local transposition flaps. More sophisticated techniques may be used at a later time (myocutaneous flaps or free flaps) if further reconstruction is contemplated. 9. Dressing must be carefully applied without constricting the extremity. A protective plaster is applied beginning from above the elbow and ending in a bonnet over the hand; this allows the recovery room nurse to monitor the vascular status of the repair. 10. The physiotherapist and occupational therapist are integrated into the perioperative care. Active range of motion exercises are begun as soon as the third day after the operation. Lightweight static and dynamic splints help to restore mobility.

Adolescent↗
PubMed1981

Evaluation of clinical microvascular anastomoses--reasons for failure.

Thrombosis in clinical microvascular anastomoses is attributed to suture errors and utilization of severely damaged recipient arteries. Histopathological specimens from 24 microvascular anastomoses and 77 vessel biopsies from free tissue transfers and replantation cases were analyzed. Suture errors of any note were rare and occurred primarily in replantation cases in which team experience varied and fatigue was common. Recipient artery damage ranged from minimal to severe; clinical analysis confirmed the devastating effect of refractory spasm associated with intramural scarring from previous trauma. Additional studies by microvascular groups are needed to clarify the causes of thrombosis and the healing mechanism of microvascular anastomosis.

Animals↗
PubMed1981

The normal healing process of microvascular anastomoses.

The vessel wall regeneration and the inflammatory response in the rabbit femoral artery and vein the first three months after microvascular end-to-end suture anastomosis was assessed histologically. The initial damage consisted of endothelial loss and partial necrosis of media and adventitia. The luminal surface was reendothelialized and the adventitial layer restored by 20 days, but the necrotized part of the media did not regenerate. Instead, the vessel wall diameter was maintained by an intimal hyperplastic response. At the anastomotic site a characteristic slight dilatation was persistent. Consequently, the vessel wall architecture was not restored to the preoperative state after microvascular anastomosis.

Animals↗
PubMed1981

Etiologic factors in pressure sores: an experimental model.

The primary etiologic factor in the production of pressure sores is considered to be pressure-induced ischemia with the threshold being 35mmHg for 2 hours. However, clinical evidence indicates that skin can withstand normothermic ischemia of 8 to 12 hours without necrosis. A detailed review of the literature indicates that previous experimental models are few in number and limited in clinical relevance. Therefore, a continuously monitored computer-controlled electromechanical pressure applicator was designed to produce pressure sores over the greater femoral trochanter of normal and paraplegic swine. Examination of the pressure site at 1 week revealed 3 groups of lesions: 1) muscle damage only, 2) muscle and deep dermis damage, and 3) full-thickness damage extending from bone to skin. A critical pressure-duration curve for the production of pressure sores is presented for normal swine. Muscle damage occurred at high pressure-short duration (500mmHg, 4 hours), whereas skin destruction required high pressure-long duration (800mmHg, 8 hours). On analysis, muscle is more sensitive than skin to the effects of pressure, and the initial pathologic changes occur in muscle. Skin breakdown did not occur with a pressure of 200mmHg for 15 hours, thus contradicting previous statements that pressure exceeding 35mmHg for 2 hours would cause ischemia with subsequent tissue necrosis resulting in a pressure sore. We hypothesis that normal tissue is far more resistant to pressure-induced ischemia that previously considered, and that the pressure-duration threshold for the production of pressure sores is lowered dramatically following changes in the soft tissue coverage due to paraplegia, infection, or repeated trauma.

Animals↗