Biomedical subjects
Publications and source records attributed to T R Stevenson.
Injuries of the fingertip and nailbed require treatment to minimize pain, speed healing, and shorten the time of functional impairment. Alternatives for therapy include simple dressing changes, graft coverage, and flap transposition. The choice of treatment is based on the location and severity of the injury.
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Sternal osteomyelitis complicates recovery in a small number of patients following median sternotomy. Techniques for operative treatment have in common the wide debridement of devitalised tissue and administration of culture-specific antibiotics. The resultant wound can be managed by delayed primary closure or transposition of well-vascularised adjacent tissue. Omentum, pectoralis major muscle and rectus abdominis muscle are suitable for transposition either alone or in combination. Our series is composed of ten patients who underwent rectus abdominis muscle transfer for the treatment of sternal osteomyelitis. The rectus abdominis obliterates dead space in the lower third of the wound, a difficult area to reach with the pectoralis major muscle. Five patients had one rectus abdominis muscle alone transposed, avoiding the aesthetic and functional deficits of pectoralis major transposition and the risks of omental transfer. Wound healing occurred in every case with a minimum of postoperative complications.
Knee and elbow injuries are seen frequently by the primary care physician and require prompt and careful treatment in order to prevent infection, preserve joint function, and avoid scarring. A thorough history and physical examination help to rule out more significant damage to the related joint, nerves, or tendons. Immobilization of the joint may be necessary to prevent dehiscence, and the patient should be instructed to return for further examination if signs of infection develop.
Neonatal Fischer 344 rat keratinocytes were cultured on a collagen sheet to create a 'quasi-skin.' The cells were grown in either control medium or a low-calcium supplemented medium to enhance proliferation. The rate of 3H-thymidine incorporation into DNA was assessed at days 3, 7, 10, and 20 to determine the effectiveness of the medium supplements. The cells grown in supplemented medium did have an elevated rate of incorporation. On days 7 and 14 post culture, the quasi-skin was used to cover full-thickness defects on the dorsum of adult male rats. The covered defects were biopsied 45 and 60 days postoperatively. Light microscopy showed the wounds to be completely re-epithelialized. Barr bodies were present at the wound site, confirming the presence of quasi-skin keratinocytes up to 60 days postoperatively.
Through autografting experiments on 9-g rectus femoris (RFM) muscles in rabbits, we substantiated a previous observation that the maximum isometric tetanic force (Po) and specific Po (N/cm2) of neurovascular-intact grafts are not different from grafts made with neurovascular repair. We then tested the hypotheses that the specific Po of vascularized grafts is significantly less than that of control RFM muscles and the deficit in the specific Po is associated with increases in connective tissue and interstitial space. The specific Po of the grafts was 65% of the value for control RFM muscles. Connective tissue protein concentration of grafts was 3.8 times greater than the control value of 16.6 +/- 3 micrograms/mg wet mass, but this only accounted for a 5% correction in specific Po. The volume of interstitial space did not differ between grafts and control muscles. We conclude that the deficit of 35% in specific Po of vascularized grafts compared with control values is partially explained by an increase in connective tissue, but a 30% unresolved deficit remains.
Rupture of a finger flexor tendon occurs most commonly in the patient with rheumatoid arthritis. We have treated two patients who suffered rupture of the flexor tendons to the little finger due to bony irregularities in the carpal tunnel unrelated to rheumatoid disease. Each irregularity was removed and the rough surface covered with a portion of the flexor retinaculum. This resurfacing affords protection against recurrent abrasion and rupture. Tendon function was restored by suturing the ruptured profundus tendon to the adjacent intact profundus tendon of the ring finger. Satisfactory function of the little finger was achieved in both patients. Neither patient has experienced recurrent rupture.
Poland's syndrome is a well-known constellation of congenital anomalies that includes varying degrees of hypoplasia involving the thoracic cage in association with anomalies of the hand. Although the latter are most frequently described as syndactyly with short or absent middle phalanges, many forms of expression were seen in a series of 20 patients. Thirty-one other anomalies were seen in this group in addition to those usually considered as part of the syndrome. Of special interest are those involving the spine and genitourinary tract that require special studies for early detection.
The vertical trapezius musculocutaneous flap has been successfully utilized for reconstruction in 13 patients with complex posterior skull and neck defects. This flap based on its vascular pedicle, the descending branch of the transverse cervical artery, provides well-vascularized tissue for coverage of defects related to chronic osteomyelitis, tumor extirpation, osteoradionecrosis, and dehisced cervical laminectomy wounds. Emphasis on flap design, including the location of the skin island, allows adequate wound coverage, direct donor site closure, and muscle function preservation. With its large size and wide arc of rotation, the vertical trapezius musculocutaneous flap provides reliable coverage for posterior trunk, cervical, and skull defects.
Viability of a vascularized free fibula transfer can be difficult to establish. It is possible, however, to assess patency of the involved microvascular anastomoses and blood flow in the vessels of the transposed fibula. A Doppler color-flow imager can be used to evaluate blood flow and vascular patency. The imager potentially can be employed in the operating room, during the immediate postoperative period, and for long term follow-up. It is non-invasive and produces a permanent record of vascular anatomy and flow characteristics.
We present a congenital deformity of the right ear, characterized by absence of the central portion of the helix and antihelix. The deformity was reconstructed by advancing retroauricular skin and closing the resultant defect with a composite graft from the posterior aspect of the left ear. This technique was performed in a single stage and required no incisions on the anterior surface of either ear. Postoperative appearance of the right ear was satisfactory, and donor deformity was minimal.
The tube pedicle flap is useful in reconstruction of an absent ear helix. However, immediate tubing of the flap may result in vascular compromise. By elevating a bipedicle flap in the postauricular region and shielding it with a silicone sheet, it is possible to allow the flap to assume a tubular shape while preventing adherence to the underlying suture line. Once mature, the flap maintains both a cylindrical shape and a sufficiently thin external diameter to provide adequate restoration of the ear helix.
The transplantation of whole skeletal muscles is a common clinical procedure. Although atypical blood flows have been reported in small free muscle grafts, the blood flow of large neurovascular-intact (NVI) and neurovascular-anastomosed (NVA) grafts have not been measured. Because the maximum specific force (N/cm2) of NVI and NVA grafts is 65% that of control muscles, we hypothesized that total and regional blood flows (ml.min-1.100g-1) of NVI and NVA grafts at rest and during twitch contractions are significantly lower than lower flows of control muscles. In rabbits, blood flows of control rectus femoris (RFM) muscles and NVI and NVA grafts of RFM muscles were measured by the radioactive-microsphere technique. In control muscles, blood flow increased linearly from 6.8 +/- 1 ml.min-1.100 g-1 at rest to 64.4 +/- 7 ml.min-1. 100 g-1 at a stimulation frequency of 3 Hz with no further increase at 4 Hz. Total blood flows in grafts were not different from the control RFM muscle values, except for a higher resting flow in NVA grafts and a lower flow at 3 Hz in NVI grafts. Minor variations in regional flows were observed. We conclude that the operative procedures of grafting and repair of blood vessels affect the vascular bed of muscles minimally, and the deficits observed in grafts do not arise from inadequate perfusion.
An important element in successful free tissue transfer is an intact recipient artery. This vessel must be anatomically accessible, structurally suitable for anastomosis, and able to transmit an adequate blood volume. In the case presented, there was radiographic evidence of recipient artery disease, with a presumed decrease in flow. However, Doppler blood flow studies predicted near normal flow. This information was useful in making intraoperative decisions regarding the suitable vessel for anastomosis.
Transfer of a free-muscle graft with application of a split-thickness skin graft is one of many techniques available for reconstruction of the massive foot injury. The durability of such a reconstruction has been questioned. We have treated nine patients suffering from foot injuries with extensive soft-tissue loss. Each patient underwent reconstruction using a free-muscle transfer covered by a split-thickness skin graft. A mean follow-up of 33 months (range 17 to 48 months) is reported for these nine patients. Each patient is ambulatory. One patient developed an ulcer on the plantar surface, which was treated successfully by flap revision and skin grafting. We feel this technique provides a durable reconstruction for significant soft-tissue loss of the foot.
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The purpose of this study was to examine the influence of the fluid dynamics of syringe irrigation on the efficacy of wound cleansing and the infection rate of experimental wounds. The pressure experienced by a surface following wound irrigation was directly proportional to the pressure within the syringe and the size of the needle. High pressure syringe irrigation effectively removed bacteria from the surface of the wound. This reduction in the wound bacterial count resulted in a decrease in the infection rate of tissues. Low pressure irrigation with an asepto syringe did not significantly cleanse the wound of its bacterial contaminants and had no demonstrable clinical merit. On the basis of these studies, high pressure syringe irrigation is being employed routinely in our emergency department for the care of traumatic wounds.
Infection within the peritoneal cavity without an identifiable source of contamination is rare. The diagnosis is one of exclusion, and can be made with certainty only after a thorough laparotomy. The response to antibiotic therapy is usually prompt and gratifying.