Biomedical subjects

W A Morrison

Publications and source records attributed to W A Morrison.

At least 109 records · Page 6Linked to original sources

PubMed1992

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↗

PubMed1992

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↗

PubMed1992

Review of Swanson trapezium implants.

Sixteen Swanson trapezium silicone prostheses are reviewed retrospectively an average of 3 years after insertion. Fifteen were performed for osteo-arthritis and one for rheumatoid arthritis. Despite a very high patient satisfaction, 14 thumbs had residual functional compromise and caused pain when performing certain tasks. Three implants were completely dislocated and another four were significantly subluxed. One patient required implant removal. Intra-osseous cysts or significant bony erosion around the implant were present in five thumbs. It is concluded that there are early significant problems associated with this procedure which make it unsuitable for use in the osteo-arthritic thumb.

Aged↗

PubMed1992

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↗

PubMed1992

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↗

PubMed1990

Prefabrication of thin transferable axial-pattern skin flaps: an experimental study in rabbits.

The arteriovenous pedicle of all known axial-pattern skin flaps enters from the deep aspect and consequently the flap must contain fat and/or muscle and be of considerable thickness. In an attempt to fabricate a thinner axial-pattern flap the femoral artery and vein of rabbits were implanted, in various vascular configurations, directly into the subdermal layer of the skin. Implantation was found to provoke an extensive outgrowth of new vessels from the implanted artery and vein, and the progress and pattern of this neovascularisation was studied by carbon gelatine perfusion and histology. Neovascularisation begins within a few days of implantation and progresses rapidly. By 8 to 12 weeks it is possible to elevate regularly a viable, large skin flap based on the implanted pedicle.

Animals↗

PubMed1990

Microvascular nail transfer.

A composite of nail and its skin appendages can be transferred for the foot to the hand by microvascular anastomosis. For technical reasons, the most suitable donor nail is from the big toe, and this most closely approximates the thumb nail. A finite portion of hemipulp must be included with the transfer to ensure adequate vascularization. Nail size can be reduced by resection of the edges of the germinal matrix so as to match the donor defects. For finger nail reconstruction, it is usually more practical to transfer the whole of the tip of the second or third toe to replace the whole of the tip of the finger. The indications of nail reconstruction by this technique are relatively rare and are predominantly cosmetic.

Age Factors↗

PubMed1990

Results of management of facial palsy with microvascular free-muscle transfer.

This paper reports our experience in facial reanimation using free innervated muscle transfer in 69 patients with long-term facial palsy. The majority of patients were treated in two stages with cross-facial nerve graft as the first stage and microvascular muscle transfer at the second stage. The gracilis muscle was used in 62 patients. A system of grading results has been utilized in the long-term evaluation. The overall final result was excellent or good in 51 percent of 47 patients who were available for follow-up. Although the results are not completely satisfactory, they justify the use of this approach to a difficult clinical problem. The results are improving as technical modifications to the procedure have evolved. The gracilis muscle is a reliable free transfer with internal anatomy conductive to use for reanimation of the paralyzed face. This type of transfer, in our experience, has proved superior to nonmicrosurgical methods for treatment of complete and severe incomplete facial palsy. The seventh cranial nerve is used in the innervation of the transferred muscle, the ipsilateral being preferable if available. The authors believe that use of the same cranial nerve is superior to methods that involve other cranial nerves, where spontaneity is often not achieved.

Adult↗

PubMed1989

An easy and safe way to dress limb flaps in the dog.

When a flap is elevated in a human, the patient is usually managed with bed rest. The same conditions are impractical in dogs. Sometimes a flap in the dog must be protected from the dog itself by applying a special cast or a bucket on the head. An easy, safe, inexpensive, and quick method to dress the dog, by simply applying hot pepper into the dressing, is described.

Animals↗

PubMed1989

Primary repair of flexor tendons in no-man's land using the Becker repair.

Forty-three digits with severed flexor tendons in no-man's land have been repaired using a modified Becker's technique. The results are analysed according to the type of laceration and associated injuries. Using White's method, 70% obtained satisfactory, 8% fair, and 22% poor results. There were three ruptures but most poor results were due to stiffness after crushing injuries or when both vascular bundles had been divided.

Adolescent↗

PubMed1989

Comparative study of vascularized and nonvascularized tendon grafts for reconstruction of flexor tendons in zone 2: an experimental study in primates.

Vascularized tendon grafts were compared with nonvascularized tendon grafts in a primate experimental model. In four monkeys, seven vascularized extensor hallucis longus grafts were placed in the foot's digital fibroosseous canal and these were compared with eight nonvascularized tendon grafts similarly placed in the opposite extremities. The juncture techniques and postoperative protocols were identical for both tendon groups. All tendons were explored 5 months after insertion. The vascular pedicle was patent in all vascularized tendons. Three tendon ruptures occurred in nonvascularized tendons and only one rupture occurred in a vascularized tendon. The digits with vascularized tendons demonstrated a significantly better simulated total active motion (117 degrees versus 128 degrees, p less than 0.05) than digits with nonvascularized tendons. The difference was even more significant when a localized tenolysis of the proximal juncture of the tendon graft was performed (215 degrees versus 138 degrees, p less than 0.01). This study supports the concept that vascularized tendon grafts may be advantageous in scarred tendon beds.

Animals↗

PubMed1989

Comparative study of the use of prefabricated bone tendon grafts and conventional tendon grafts in flexor tendon reconstruction.

In tendon grafting the weakest area is the junction between the grafted tendon and bone. In dogs a strong union between tendon and bone can be produced by threading the flexor carpi radialis tendon through a hole drilled in the radius. In experimental repair of canine flexor tendons, 3 weeks after operation the strength of the union between a composite bone-tendon graft prepared in this way is double that of the bone-tendon junction of a conventional graft. Use of prefabricated bone-tendon grafts should permit earlier postoperative movement and limit formation of adhesions between a tendon graft and its bed.

Animals↗

PubMed1989

The effect of prior elevation of skin flaps and ischemia on blood thromboxane levels.

The physiological factors that allow for the survival of ischemic skin flaps have not been clearly elucidated. Previous work by others has shown that elevation of a flap 24 hours before an episode of complete ischemia significantly improved survival, presumably by delaying the onset of the no-reflow phenomenon. The current study, using an epigastric flap, investigated the role of thromboxane in these events by observing postischemic plasma levels of thromboxane B2, the stable metabolite of the short-lived thromboxane A2. Acutely ischemic flaps were compared with those elevated 24 hours before ischemia. After the ischemic insult, blood was drawn from the venous effluent of the flaps. Thromboxane levels after 4 hours of ischemia were significantly decreased (p less than 0.001) in the postischemic period in those flaps elevated 24 hours before ischemia compared with flaps that had undergone ischemia acutely. Moreover, acutely ischemic flaps had significantly more thromboxane than nonischemic controls (p less than 0.001). These results confirm the importance of thromboxane metabolism in the no-reflow phenomenon.

Animals↗

PubMed1989

Hydrostatic distention and pharmacological treatment of epinephrine-induced microarterial spasm.

The efficacy of using hydrodistention and vasodilatory drugs to relieve spasm in arteries was investigated. The femoral arteries of 64 rabbits (divided into five groups) were placed in spasm by the topical application of epinephrine (1 mg/ml). In group A (controls) vasospasm was induced without further treatment. In group B vasospasm was induced, and the arteries were hydrodistended with normal saline. In three additional groups vasospasm was induced and either 10% lidocaine hydrochloride (group C), verapamil hydrochloride (group D), or chlorpromazine hydrochloride (group E) was applied. Thirty minutes later the vessels were hydrodistended. All vessels were measured at set intervals, and some specimens were retained for light and electron microscopy. All methods of spasm relief were successful, although to varying degrees. Hydrodistention alone produced the widest dilation for the longest time. Lidocaine was the most successful drug treatment alone. Verapamil followed by hydrodistention was the most successful combination regimen, but did not produce better results than hydrodistention alone. Hydrodistention alone produced significant arterial wall damage, resulting in permanent structural modifications. Prior vasodilatory drug treatment reduced but did not eliminate hydrodistention damage. Although hydrodistention dilates for longer periods than vasodilatory drugs, the arterial wall damage associated with hydrodistention indicates that it should be used only when all other methods of vasodilation have failed.

Animals↗

PubMed1989

Creation of distal canine limb lymphedema.

A canine model of distal limb lymphedema was established in order to study the treatment of this condition by lymph node transfer. This model was more difficult to establish than whole-limb lymphedema. Significant edema was achieved by a combination of preoperative irradiation and circumferential removal of skin from the irradiated areas followed by removal of the contents of the popliteal fossa. Despite these measures, it was not possible to produce lymphedema in every case, possibly because of the presence of lymphaticovenous shunts and panvascular compensation mechanisms.

Animals↗

PubMed1988

The significance of resection length on the patency rate, and the histopathology, of experimentally avulsed and microsurgically repaired blood vessels.

The significance of resection length on patency rate, and the histopathology, of microsurgically repaired avulsed blood vessels was examined at 3 weeks in two groups of experimentally avulsed rabbit femoral arteries repaired by different surgeons and in a single series of avulsed and repaired veins. All veins were patent 3 weeks after avulsion and microsurgical repair. Histopathology indicated that the vast majority of lesions in veins were removed at resection. Surgeon A achieved 75% patent arteries and Surgeon B achieved 100% arterial patency (resecting 3.7 mm more on average than Surgeon A). Histopathology revealed numerous luminal circumferential lesions remained in the avulsed artery wall following resection. These lesions were sites of smooth muscle cell proliferation and neointima formation. Although similar arterial damage occurs in human avulsion, considerably lower patency rates are achieved for human arterial avulsion repair than were reported in this experimental study. Factors in addition to vessel wall damage must therefore be involved in thrombosis and occlusion of repaired avulsed arteries. Such factors might be lengthy ischaemia time and severe spasm.

Anastomosis, Surgical↗

PubMed1988

The use of long synthetic microvascular grafts to vascularise free flaps in rabbits.

A 5 cm length of 2 mm internal diameter (i.d.) synthetic, expanded polytetrafluoroethylene (PTFE, or Gore-Tex) vascular graft was used to connect 25 rabbit inferior epigastric flaps to the contralateral femoral vessels. In 15 animals an expanded PTFE graft connected the opposite femoral artery to the flap while the ipsilateral venous drainage remained intact. In the remaining 10 animals an expanded PTFE graft was used to replace the venous drainage of the flap and connected to the opposite femoral vein while the ipsilateral femoral artery supplied the flap. Flap survival and graft patency were evaluated over 3 weeks. Ten of 15 flaps with intra-arterial grafts survived at 3 weeks (67%). Only 27% (4/15) of their supplying grafts remained patent for 3 weeks, although 67% (10/15) were patent at 10 days. All 10 flaps, where expanded PTFE grafts replaced venous outflow, failed within 36 hours. At exploration these grafts were thrombosed or collapsed. In conclusion, currently available 2 mm (i.d.) expanded PTFE vascular graft cannot maintain patency in a low blood flow circulation supplying an isolated free flap.

Animals↗

PubMed1988

Long microvenous allografts in rabbit femoral arteries and veins.

In this study the patency of long microvenous allografts in rabbits with and without immunosuppressive drug therapy was investigated. Eighty-two microvenous autografts (controls) and allografts were transplanted into rabbit femoral vessels. Veno-venous autograft controls were 100% patent at 3 weeks. Rejection of non-immunosuppressed veno-venous allografts consistently produced occlusion between 15-20 days. Thrombus filled the lumen, and a leucocyte invasion destroyed the graft wall. In contrast vein allografts into arteries were 100% patent at 3 weeks; this was reduced to 50% at 4 weeks. Low (5 mg/kg/day) and high (20 mg/kg/day) doses of hydrocortisone over 21 days improved the 3 week patency in veno-venous allografts to 28.5% and 57.0% respectively. Cyclosporin A (15 mg/kg/day) over 8 or 22 days significantly increased the patency rate of veno-venous allografts to 100%. Only cyclosporin A treated rabbits maintained allografts of normal vein morphology to 3 weeks.

Animals↗