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Biomedical subjects

D P Hanel

Publications and source records attributed to D P Hanel.

At least 37 records · Page 2Linked to original sources
PubMed1993

Index transposition after resection of the long finger ray.

Ten patients underwent index-to-long-finger ray transposition for repair after resection of the long finger ray. Care was taken to preserve the second web space and prevent painful neuromas. Rigid internal fixation was achieved with a T plate, and mobilization was started immediately. There were no nonunions. Postoperative motion was equal to preoperative motion in acute cases and equal or better in chronic cases. Mean grip strength was 0.65, and pinch strength was 0.78 compared with the uninjured hand. There were no painful neuromas, hypersensitive scars, or deterioration of monofilament or two-point sensibility. The breadth and appearance of the first and second web spaces were equal bilaterally. Digit alignment and rotation were normal. The six patients receiving worker's compensation returned to work in between 3 and 24 weeks, and the other patients returned in between 11 days and 12 weeks.

Acute Disease↗
PubMed1993

Knee arthrodesis using combined intramedullary rod and plate fixation.

Intramedullary arthrodesis of the knee is a satisfactory method for treating difficult salvage cases of infected arthroplasty, bone loss, and severe osteoporosis. In eight cases, a medial compression plate was routinely used for complete fixation. Union occurred in all cases, including two proximal tibial segmental allografts. Five previously infected cases were healed at follow-up examination (average, six to 44 months). Complications included proximal rod prominence, partial peroneal nerve palsy, recurrent sepsis in one case, and tibial shaft perforation on nail insertion. Seven of the eight patients used some form of walking aid for extended ambulation. Leg length was generally 1.5-2.5 cm shorter than the opposite limb.

Adult↗
PubMed1992

The de-endothelialized rat carotid arterial graft: a versatile experimental model for the investigation of arterial thrombosis.

A novel model of arterial thrombosis was developed. A mechanical endothelium-denuding injury was created (using a scalpel blade) on harvested, freezer-stored rat carotid arteries. Vessel length of 5 mm. were grafted into the femoral arteries of recipient Sprague-Dawley rats using microvascular anastomotic technique. Patency rates in untreated animals were compared with those in animals receiving systemic aspirin or heparin. The control group patency after 2 hours of flow was 15%, while grafts in aspirin- and heparin-treated animals achieved 35% and 95% patency rates, respectively. Uninjured non-frozen carotid grafts in untreated animals yielded a 95% patency rate, while frozen grafts achieved an 80% patency. Therapeutic levels of aspirin, heparin, and urokinase were confirmed through tail bleeding and whole blood clotting tests, as well as platelet aggregation studies and scanning electron microscopy of the graft lumenal surfaces. A long-term series using syngeneic grafts placed in recipients (Lewis-to-Lewis) and employing systemic heparinization demonstrated maintenance of patency for 4 weeks. Scanning electron microscopy revealed good re-endothelialization, well advanced by one week. Histology confirmed the regrowth of endothelial cells, but showed sparse cellular repopulation of medial and adventitial layers. The mechanical injury model was compared to enzymatic de-endothelialization (using trypsin or collagenase), for which patency rates were similar (10% and 0%, respectively). Trypsin de-endothelialized vessels were tested in vitro for the amount of active trypsin remaining bound to the lumenal surface; no detectable activity was found when trypsin inhibitor was applied following trypsin treatment. The versatility of allowing both in vitro evaluation and in vivo patency assessment demonstrates the uniqueness and value of this new model, offering an avenue toward more direct investigations of surface-mediated thrombotic processes.

Anastomosis, Surgical↗
PubMed1992

Comparison of the influence of intralumenal irrigation solutions on free flap survival.

Heparin is commonly included in the irrigation solution used during microvascular surgery. Evidence has accumulated to indicate a beneficial effect of heparin on anastomotic patency, implying that its topical use is critical to success even in routine microvascular repairs. This investigation compared heparin and urokinase as additives to the irrigation solution (Ringer's lactate) used during rat groin free flap replantation. A newly trained microsurgeon performed all surgical procedures to lower the possible success rate through microsurgical inexperience and, thus, to create a stronger challenge for the topical irrigant. Solutions were administered on a blinded, randomized basis. Vessel patency and flap survival were followed for 7 days. No statistically significant differences were found between any of the treatment groups: patency and survival rates of 67% for heparin, 57% for urokinase, and 73% for controls (vehicle only). The flap failures that occurred may have been attributable to undetected technical errors due to the microsurgical inexperience of the surgeon. In a separate series, an experienced microsurgeon achieved 93% success using vehicle without additives for irrigation. These results suggest that topical heparin or urokinase is not essential for achieving high levels of success during microvascular surgery.

Administration, Topical↗
PubMed1992

Predictive value of psychological screening in acute hand injuries.

Difficulties in adjustment frequently accompany severe hand injuries. The purpose of this study was to determine whether presurgical screening could predict long-term adjustment problems. One hundred thirteen patients with severe hand injuries completed a presurgical questionnaire evaluating flashbacks, avoidance, and causal factors pertaining to the injury. Patients were evaluated by a psychologist within 5 days after surgery and again 6 months later. Flashbacks initially occurred with equal frequency in occupationally and nonoccupationally injured groups. At 6-month follow-up 50% of the occupationally injured patients and 25% of the nonoccupationally injured patients had flashbacks. Avoidance of the activity at which patients were injured was also assessed. Among occupationally injured patients, 52% initially reported no avoidance compared with 17% at follow-up. Patients with nonoccupational injuries showed more initial avoidance (68%), with slightly less at follow-up (61%). Of the occupationally injured patients, 46% initially reported personal error or fatigue as the cause of their injury, but only 6% reported this as the cause at follow-up; it is interesting that at 6-month follow-up 81% of this group reported machine failure or lack of safeguards. Among nonoccupationally injured patients, 71% reported personal error as the cause of injury presurgically and 66% at 6-month follow-up. Presurgical screening appears to be a valid means of identifying persons at risk of ongoing adjustment problems after hand injury. A screening interview can easily be conducted in less than 5 minutes.

Accidents, Occupational↗
PubMed1992

Antithrombotic benefit of subendothelium-bound urokinase: an experimental study.

To improve the outcome of extremity replantation, microsurgeons have administered systemic antithrombotic agents (e.g., heparin, aspirin, dextran). To obviate the risks associated with systemic anticoagulation, we have investigated the use of topically applied urokinase for its binding capacity to arterial subendothelium and for its ability to prevent subsequent thrombosis. An arterial model of thrombosis associated with intimal deendothelialization was developed. Donor rat carotid arteries were everted and mechanically deendothelialized with a scalpel blade. The vessels were next subjected to one of several treatments, which included 30-minute incubation with urokinase, heparin, or vehicle (lactated Ringer's solution). The vessels were then washed, reinverted to normal orientation, sectioned into 5 mm lengths, and grafted into the femoral arteries of recipient rats. Two-hour patency rates were 25% for controls (n = 20), 10% for heparin-treated vessels (n = 10), and 55% for urokinase-treated vessels (n = 20); this last was significantly greater than the other two groups. In vitro investigations revealed that urokinase has a high capacity for binding to subendothelium, with a release half-life of approximately 20 minutes. Surface-bound urokinase was found to have proteolytic activity similar to that of urokinase in solution. These results indicate that urokinase may be a more beneficial irrigating solution additive than heparin for repair of traumatized vessels.

Administration, Topical↗
PubMed1992

The osteocutaneous fibula flap: an anatomic study.

Recent studies related to the fibula flap have disagreed regarding the anatomy of the cutaneous branches of the peroneal artery. To clarify this issue, various dissections of 35 injected fresh cadaver legs were done. Identifiable skin branches were found in 23 of 25 dissections. Skin branches from the proximal third of the peroneal artery always travelled an intramuscular course. Skin branches from the distal two-thirds of the peroneal artery were usually affixed to the posterior crural septum. Legs with peroneal artery skin branches had from three to seven branches (average: 4.7); each branch contributed to the fibular periosteal blood supply. The most reliably found skin branch was located within 2 cm of the fibula midpoint. These findings reinforce the fact that a large skin island supplied by branches of the peroneal artery can be harvested with the fibula flap, and that the most reliable cutaneous vessels are found in the lower two-thirds of the leg, run posterior to the fibula in the posterior crural septum, and are always associated with muscular side branches.

Fibula↗
PubMed1992

The influence of diabetes on free flap transfer: I. Flap survival and microvascular healing.

Although recent clinical case presentations suggest that diabetes does not predispose free tissue transfers to increased risk of failure, this remains an open question. The present study used a syngeneic rat strain (Lewis) for free groin flap transplantations between normal rats and streptozotocin-induced diabetic rats (2 months' duration of symptoms), to investigate the influence of diabetes on flap transfer. Flap survival at 1 week, vascular patency, flap histology and ultrastructure, and scanning electron microscopy of anastomotic sites and of corrosion casts of flap vasculature were used as bases for comparison. No differences were found in comparisons of flap survival between any groups of transfer combinations (normal flap onto normal recipient, diabetic flap onto normal recipient, normal flap onto diabetic recipient, and diabetic flap onto diabetic recipient); 100% success was achieved in each group. No differences were found in histology or corrosion casts. Transmission electron microscopy revealed a thickening of the capillary basement membrane in rat diabetic skin after only 8 weeks of symptoms. This ultrastructural finding is consistent with similar capillary basement membrane thickening seen in many other tissues of short- and long-term diabetic animals and humans. Re-endothelialization across the arterial anastomosis at 2 weeks postoperatively was significantly faster in normal versus diabetic animals (p less than 0.05). The predominantly negative findings of this study support the application of free flap transfers in diabetic patients. It is concluded that reconstructive efforts involving free tissue transfer may not be contraindicated in diabetic patients.

Animals↗
PubMed1992

The influence of diabetes on free flap transfer: II. The effect of ischemia on flap survival.

Insulin-dependent diabetes mellitus causes microangiopathic changes in many tissues, including skin and muscle. It is not known if such changes are detrimental to free flap transfer, particularly after extended ischemia. To address this issue, we used an experimental design by using a syngeneic rat strain (Lewis) for free groin flap and muscle flap transplantations from streptozotocin-induced diabetic rats (2 month's duration of symptoms) to normal rats. Flaps from age-matched normal donors were transplanted to normal recipients for control comparisons. Groin flaps were stored ischemically for 12 or 18 hours at room temperature, or for 48 hours in the cold (4 degrees C) before transplantation. Flap survival and vascular patency were assessed at 7 days. Cutaneous maximus muscle flaps were transplanted to the groins of recipients after 6 hours of room temperature ischemia. Vascular patency, muscle viability, flap weight change (edema), and dehydrogenase activity were assessed after 2 days of reperfusion. Seventy percent, 67%, and 73% of diabetic groin flaps survived after 12, 18, or 48 (cold) hours of ischemia, respectively, in comparison with 90%, 73%, and 87% of normal flaps undergoing the same respective ischemia periods. The differences were not significant, even when the data were pooled (p greater than 0.1). Muscle flaps also showed no significant differences for the parameters studied. These results support the use of microvascular reconstructive surgery in diabetic patients, suggesting that moderate ischemic challenges do not compromise free flap transfer or extremity replantation.

Animals↗
PubMed1992

High-resolution bone scintigraphy of the adult wrist.

Bony anatomic landmarks of the wrist (e.g., pisiform, hook of hamate, radioulnar joint, and styloid processes of the radius and ulna) were routinely identified in 28 adult patients examined for wrist pain. With the wrists prone and immobilized, bone scintigrams were obtained for 500,000 counts with an asymmetric (133 to 161 keV) Tc-99m energy window and either a converging (best choice) or straight-bore, high-resolution collimator. High-resolution scintigraphy precisely localized degenerative joint disease (nine patients), scaphoid fractures (five), pisiform fracture (one), lunate avascular necrosis (one), radioulnar arthritis (one), septic or inflammatory arthritis (six), ulnocarpal impingement (two), and reflex sympathetic dystrophy syndrome (two). Images obtained palm down with the wrist in ulnar deviation helped identify increased uptake within the scaphoid. Fracture and significant bone or joint disease were excluded in one patient.

Adult↗
PubMed1992

Management of acute and chronic vascular injuries to the arm and forearm. Indications and technique.

Acute arterial injuries of the upper extremity account for half of civilian arterial injuries in the United States. The great majority of these injuries are due to penetrating trauma, with stab wounds and gunshot wounds being the most common cause. The history of the injury and a careful physical examination will identify most injuries. Arteriography should be performed when a vascular injury is suspected but not confirmed by physical examination. Reconstruction of critical vascular lesions is essential for restoration of flow distally. Noncritical lesions may be repaired in most cases, with long-term patency rates averaging 50% to 68%. Although amputation is uncommon after upper-extremity vascular injury, long-term disability can be significant in those patients with concomitant nerve injury. Chronic upper-extremity ischemia may be secondary to atherosclerotic occlusive disease, aneurysms, or arteriovenous fistulas. Angiography will delineate the diseased or occluded arterial segment, allowing bypass to be successful in more than 90% of cases. With careful attention to proper diagnosis and treatment, good to excellent long-term relief of symptoms can be obtained.

Acute Disease↗
PubMed1991

Experimental study of the influence of arterial trauma on dependent distal tissue survival.

An experimental model was developed combining arterial trauma with island flap creation using the rat groin flap system. Flap arteries were subjected to crush/avulsion injuries with subsequent microvascular repair. A second series involved resection 4 hr after thrombosis of injured flap arteries and interpositional vein grafting to reestablish circulation. A single bolus of systemic heparin was administered to half of the animals from each series on a blinded, randomized basis. Arterial patency at 7 days correlated with flap survival. There was no case of partial flap loss. Patencies improved in the first series from 31% to 71% with heparin administration (P less than 0.05) and from 58% to 90% in the second (not significantly different). A third series involving immediate resection of traumatized vessel and vein graft replacement achieved a patency of 92% (without heparinization). These results support the value of replacement of all traumatized arterial tissue with vein grafts and indicate the efficacy of systemic heparin (in single bolus) for enhancing the likelihood of maintaining patency. Furthermore, it is suggested that the occurrence of a thrombogenic site in the arterial inflow to a region of dependent tissue does not lead to partial tissue loss, and thus thromboembolic events may not be responsible for this clinical phenomenon.

Anastomosis, Surgical↗
PubMed1991

Free tissue transfer for reconstruction of traumatic limb injuries in children.

Free tissue transfer was used for the reconstruction of soft tissue defects in 94 children. Of the 127 procedures performed, the latissimus dorsi, scapular skin, lateral arm skin, rectus abdominis, and gracilis were used with the greatest frequency. The microsurgical success rate was 96%. Microsurgical failures were repeated, successfully, and in all cases the limbs were salvaged. Other than having to deal with decreased vessel size and avoiding continuous suture lines, there appears to be little difference in technique or outcome of free tissue transfer when compared to adults.

Adolescent↗
PubMed1990

Vascularized fibular osteocutaneous graft: surgical technique and clinical study.

This paper presents a detailed description of the dissection of the vascularized fibular osteocutaneous graft. The fibular graft is vascularized by the peroneal artery. A cutaneous vessel takes origin from the peroneal artery within 2 cm of the fibular midpoint in more than 90% of legs. The reliability of this vessel allows a skin island to be transferred with bone, to act as a monitor of vascularity and provide for skin loss. Ten clinical cases confirmed the reliability of the surgical dissection when centred at the midpoint of the fibula.

Adolescent↗