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Biomedical subjects

W A Morrison

Publications and source records attributed to W A Morrison.

At least 19 recordsLinked to original sources

Biochemical analysis of the venous flap in the dog.

There has been great interest stimulated by reports on factors influencing the survival of skin flaps which possess only venous inflow and outflow, i.e., venous flaps. The present study serially (Days 1, 2, and 4 postoperatively) observed several biochemical factors which might affect flap survival. ATP levels were measured to assess endogenous energy stores, malonyldialdehyde (MDA) and xanthine oxidase (XO) to estimate free radical production, superoxide dismutase (SOD) to quantify antioxidant defenses, and edema to measure inflammatory changes. Eighteen thighs on nine dogs were assigned randomly to one of three groups: full-thickness skin grafts, flaps based solely on the saphenous artery and vein (AV flaps), or flaps based solely on the saphenous vein (venous flaps). These were regarded as being mostly ischemic, totally perfused, and partially ischemic, respectively. Control skin biopsies were obtained adjacent to surgical sites. AV flaps and control skin were similar in all respects. Venous flaps compared with skin grafts were significantly less edematous (P less than 0.01) had less MDA and XO (P less than 0.05), but no significant differences in SOD and ATP levels. However venous flaps had significantly less ATP than AV flaps (P less than 0.01). Thus venous flaps survive despite depletion of ATP levels. These results suggest that decreased free radical production and lessened edema may be important factors in promoting ultimate survival of venous flaps.

Adenosine Triphosphate

The plantaris tendon as a tendo-osseous graft. Part I. An anatomical study.

Comparative studies have shown that bone-bone union develops faster than a junction between grafted tendon and bone, and would thus allow earlier post-operative movement, limiting adhesion formation. In this context the nature of the insertion of the plantaris tendon into the calcaneus is reviewed as a possible source of composite bone-tendon grafts. It is proposed that the composite plantaris tendon with its bony block attachment is inserted through a hole in the distal phalanx of the finger creating an immediate firm distal fixation. From cadaver dissections it was found that in at least 80% of cases the insertion of the plantaris tendon was directly into the calcaneus, independent of the tendo Achilles, and was therefore suitable for use as the proposed tendon graft.

Bone Transplantation

The plantaris tendon as a tendo-osseous graft. Part II. Clinical studies.

To minimize adhesions following tendon repair, early post-operative movement is recommended. This has proved difficult with tendon grafting because of weakness of the repair sites, particularly distally, and because of slow revascularization. A potential solution is the use of a composite tendon-bone graft in which a bone block is attached to the end of the tendon. The tendon is threaded through a hole in the distal phalanx from the dorsal to the palmar side and impacted like a cork to create an immediate strong fixation. The tendon itself is then tunnelled through the pulley system and the proximal repair is carried out with a multiple weave technique which can withstand immediate active movement. The ideal tendon-bone complex is the plantaris attached to a segment of calcaneus. A preliminary report with two case studies is presented.

Adult

Thumb and fingertip reconstruction by composite microvascular tissue from the toes.

Toe-pulp web flaps have the potential to almost replicate the missing tissues resulting from defects of the thumb and fingers. The possibility of short- and long-term donor site morbidity and the technical demands of these transfers limit their use mainly to largish defects on the dominant sensory aspects of the radial digits. This limitation is especially true of the thumb, where a large volume of tissue is usually required. The toenail can be included or transferred alone. A logical extension of these pulp and nail flaps is the wrap-around procedure for total thumb amputations at or distal to the metacarpophalangeal joint. In this procedure, a sleeve of skin, pulp, and nail is wrapped around an iliac crest bone graft to create an almost exact size match of the missing thumb while preserving all of the toes. Palmar or first-web defects in the hand do not need specialized skin replacement for function, and foot flaps are rarely indicated in these sites.

Finger Injuries

Recent advances in plastic surgery.

Scarless healing and the creation of like-tissue for reconstruction have been the aims of plastic surgery since its inception. Recent advances bring us even closer to the ideal.

Cicatrix

Microvascular great toe transfer for congenital absence of the thumb.

Two cases of microvascular great toe transfer for congenital absence of the thumb in children are reported. A rationale and operative details are discussed. A long term follow up is needed, but at this stage the results are most encouraging. There has been no interference with gait.

Child, Preschool

Neurovascular free flaps from the foot for innervation of the hand.

Microneurovascular flaps from the first web space of the foot offer a solution to upgrade sensibility of the denervated hand. Based on the dorsalis pedis artery, it allows simple dissection and a large vessel for easy and safe anastomosis. Seven cases are presented in which combinations of the first web anatomy for a variety of denervation injuries were used. The technique is ideally suited in those cases where no areas of island flap tissue are available for transfer.

Adolescent

Neurovascular free foot flaps in reconstruction of the mutilated hand.

The neurovascular free flap from the first web region of the foot affords unrivalled potential for refurbishing sensibility to the denervated hand. Its greatest application is when no conventional island flap tissue remains for transfer. Its two-point discrimination is only moderate, but when used for thumb reconstruction, its sensibility is adequate because no functional substitute exists. Functionally and cosmetically it is superior to other methods of thumb reconstruction because of its pulp, size, and nail availability. There are no finger identification problems and secondary donor defects are minimal.

Adult

Clinical experiences in free flap transfer.

In this series of 62 free flap transfers, 48 (80%) have been successful. There have been a significant number of vascular complications, 39% of which the majority were arterial thrombosis. Fifty per cent of those which thrombosed were salvaged on exploration and revision of the vessels. The frequency of complications has diminished with experience but they remain significantly high. Free flap surgery demands considerable expertise in both donor site dissection and microvascular technique. Two surgeons with microvascular experience, each with adequate assistance, are preferred and ready availability of operating room is essential. Close postoperative observation and readiness to revise anastomoses are equally important. About 50% of failed free flap sites have been repaired by application of split skin grafts.

Adolescent

Digital replantation: clinical experiences.

In a series of 130 digital replantations successful revascularization has been obtained in 74% of cases. Arterial thrombosis is the most common cause (65%) of all failures. A useful digit can be obtained following replantation and the surgery is particularly indicated for amputated thumbs and in hands suffering multiple injuries. Precautionary measures against bleeding are absolutely essential. Primary tendon and nerve repairs are advocated. Vascular occlusion may be corrected by revisional surgery and secondary surgery can improve tendon nerve or joint function.

Adolescent

Microsurgery.

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Adolescent

A long-term review of digital replantation.

An analysis of the first 130 cases of digital revascularization and replantation performed at St Vincent's Hospital, Melbourne, during the period 1970-1977, confirms the long-term functional value of these procedures provided that strict indications for replantation are adhered to. Patient satisfaction has been almost universal, and objective testing shows that the most satisfying aspect of the procedure is the quality of sensory return. Flexor tendon function and the range of joint movement, however, are universally poor, and all patients complain of sensitivity to cold. The thumb has been by far the most satisfactory digit to replant, and avulsion injuries gave the poorest results, from the point of view of both survival and long-term function.

Adolescent