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Biomedical subjects

G B Stark

Publications and source records attributed to G B Stark.

At least 55 records · Page 3Linked to original sources

Comparison of the effect of a collagen dressing and a polyurethane dressing on the healing of split thickness skin graft (STSG) donor sites.

Recent advances in the resurfacing of burn wounds with dermal equivalents and collagen preparations have shown the efficacy of collagen. To investigate the benefits (if any), standardised split skin donor areas were chosen to compare the influence of collagen on re-epithelialisation. A bovine collagen preparation consisting of type-I collagen was prospectively compared with polyurethane film dressing in a study of 20 split thickness skin graft donor sites. The rates of epithelialisation, the discomfort experienced by the patients and the convenience of the dressings were assessed. The median time from operation to the observation of complete healing was 7.5 (+/- 2.5) days for the donor sites dressed with the collagen membrane and 12.5 (+/- 3.4) days for the the donor areas dressed with a polyurethane film (p < 0.001). The discomfort experienced by the two groups of patients was significantly less after wound coverage with collagen (p < 0.005). Haematomas or seromas that required repeated aspiration was seen under the polyurethane film dressing. The collagen dressing was more expensive than the polyurethane film, but improved wound healing compared with the polyurethane dressings.

Collagen↗

Preexpansion of the tensor fasciae latae for free-flap transfer.

Preexpansion has become an established technique to prefabricate elective free flap transfers. We report the use of the tensor fasciae latae flap as a donor site in two cases for reconstruction of a burn scar neck contracture and an unstable contralateral below-knee amputation stump, of which other donor sites were ruled out either by the patients' condition or by choice. Implantation and transfer were straightforward and the donor sites of very large flaps were minimized by preexpansion. The preexpanded muscle fasciocutaneous flaps were transplanted with microsurgical anastomoses of the vessels. Apart from a small area of necrosis at the distal tip of the flap developing on the sixth postoperative day, which we excised in a second operation, there were no major complications. The advantages of the combination of preexpansion and free flap transfer as well as the unique anatomical and functional qualities of this musculocutaneous unit are emphasized.

Adult↗

[Biological wound tissue glue systems in wound healing].

Tissue engineering relies on in vitro cell culture, biocompatible matrix materials and genetic engineering with growth and differentiation factors for guided tissue regeneration. Biogenic or semisynthetic biomaterials are an alternative as cell carriers: To circumvent the disadvantages of conventional keratinocyte sheet grafts, a keratinocyte fibrin glue suspension KFGS (H. W. Kaiser et al., Burns 20: 23, 1994), which mainly consists of epidermal stem cells, has been tested experimentally in nude mice and clinically in extensive burns and chronic wounds. In the "in vivo culture" on the wound, the non-confluent keratinocytes form a differentiated epithelium within days. Current research aims at guided dermal regeneration by a combination with allodermis or biomaterials (collagen sponges like TissueFaszie, Microspheres etc.). Fibrin glue (Tissuecol) has also been tested successfully as matrix for other cells like chondrocytes and fibroblasts transfected with growth factor genes (EGF/KGF).

Animals↗

[Surgically-induced angiogenesis as basic principle in treatment ov hypovascularized wounds--the nutritive flap].

Chronic wounds of the lower extremity as a result of diabetes, arteriosclerosis and microangiopathy are of significant clinical relevance, as they result in immobilization, extended hospitalization and cost-intensive treatment. Via transfer of well-vascularized tissue onto chronic wounds as a free transplanted muscle flap, if necessary connected to a venous bypass, angiogenesis is induced and wound healing improved. This concept leads to nonamputational therapy.

Arteriosclerosis↗

MR imaging of the carpal tunnel.

OBJECTIVE: Investigations were conducted regarding changes of carpal tunnel shape during wrist motion and the variations of space for the median nerve as well as the preoperative signs of carpal tunnel syndrome (CTS) and the postoperative restitution. METHODS: Axial MR images (1.0 T) were performed at the level of the distal radioulnar joint, pisiforme bone and hook of hamate level of 20 wrists of patients with clinical symptoms of CTS and further 20 wrists of volunteers. This was conducted with the wrist in neutral position, 45 degrees extension and 45 degrees flexion. T2-weighted signal intensity of the median nerve were measured in 18 patients pre- and postoperatively. RESULTS: The increase of the cross-sectional area of the median nerve at the pisiform level and the flattening of the median nerve at the hook of hamate level as well as the volar bowing of the flexor retinaculum at the pisiform and hook of hamate level were significantly greater in patients with CTS than in those with normal wrists (P < 0.05-0.001). In postoperative follow-up studies the distal flattening of the median nerve recovered in 94%. The signal intensity of the median nerve on T2-weighted images decreased in 67%. CONCLUSIONS: Flexion at the pisiform and hamate level as well as extension at the pisiform level narrows the space available for the median nerve potential leading to compression of the median nerve. MR imaging is accurate and reliable for diagnosis and postoperative follow-up of CTS.

Adult↗

[The value of sonography for the discovery of complications after the implantation of silicone gel prostheses for breast augmentation or reconstruction].

PURPOSE: To determine sensitivity and specificity of real-time ultrasonography in detecting breast implant complications. MATERIAL AND METHODS: The results of preoperative ultrasonography of 121 silicone implants in 65 patients were compared with the results after operative implant removal. RESULTS: With a sensitivity of 89.25% and a specificity of 92.1%, complications such as gel bleeding (n = 43), rupture with leakage (n = 63), and implant dissolution (n = 4) become manifest. Capsule formation, fibrosis, siliconoma and calcifications were often underestimated in their extent. Negative ultrasonography findings were found in 10.7% (n = 13) with positive clinical findings. CONCLUSIONS: The combination of clinical and ultrasonography findings leads to the detection of implant complications.

Adult↗

Median nerve compression can be detected by magnetic resonance imaging of the carpal tunnel.

OBJECTIVE: Clinically symptomatic carpal tunnel syndrome is not necessarily accompanied by impaired nerve conduction values. Surgical decompression, however, may immediately lead to complete and lasting relief of symptoms in these patients. Because minimally invasive techniques have reduced perioperative morbidity and vocational impairment related to operative decompression, the decision to decompress symptomatic patients (despite still unimpaired nerve conduction values) might be subject to discussion in the future. New diagnostic tools may be helpful in deciding which therapeutical options to choose. When the wrist is held either in flexion or in extension, the carpal tunnel pressure increases. To investigate the dynamic changes of the carpal tunnel shape during wrist motion, as well as the variations of space for the median nerve and its signal intensity in T2-weighting, magnetic resonance imaging (MRI) was performed on patients and healthy volunteers alike. Restitution and the persistence of pathological findings were assessed pre- and postoperatively. METHODS: MRI (1.0 T) was performed on 20 wrists of patients with clinical symptoms of carpal tunnel syndrome (CTS) and pathological nerve conduction values. Healthy volunteers (20 wrists) were matched according to sex and age. MRI was performed in neutral, 45-degree extension, and 45-degree wrist flexion positions. T2-weighted signal intensity of the median nerve was measured in 18 patients pre- and postoperatively. RESULTS: The cross-sectional area of the carpal tunnel in patients with CTS tends to be smaller than that found in nonsymptomatic volunteers. The cross-sectional area of the carpal tunnel decreases during wrist flexion at the pisiform and hamate level. During wrist extension, the cross-sectional area of the carpal tunnel decreases at the level of the pisiform. During extension, it increases at the level of the hamate. The cross-sectional area of the median nerve showed an increase at the pisiform level (P < 0.05), a flattening of the median nerve at the hamate hook level (P < 0.05), and palmar deviation of the flexor retinaculum at the pisiform and hamate hook level (P < 0.001). This was significantly greater in CTS patients than in individuals with normal wrists. Postoperatively, the distal flattening of the median nerve recovered in 94% of the cases reviewed. Although the signal intensity of the median nerve on T2-weighted images decreased by 67%, the motor latency recovered in only 39% of the cases. CONCLUSION: The carpal tunnel was smaller in CTS patients than in healthy volunteers. During flexion and extension, the space available for the median nerve narrows. This may lead to potential median nerve compression. MRI is accurate and reliable for diagnosis and postoperative follow-up of carpal tunnel syndrome. In cases with obvious clinical symptoms and yet not measurably impaired median nerve conduction values, it may be helpful in making a decision for surgical decompression.

Adult↗

[Morphology of the carpal tunnel. Movement studies in patients with constriction symptoms and healthy probands using MR tomography].

The morphological correlation of the phenomenon of increased pressure in the carpal tunnel during wrist flexion and extension--as has been proved though measurements using wick-catheters--was studied in healthy subjects (n = 15) and symptomatic patients with carpal tunnel syndrome (n = 15). Our own measurements using magnetic resonance imaging (MRI) showed that there is a significant reproducible decrease in carpal tunnel diameter when the wrist is held in position of either flexion or extension. During flexion the diameter is decreased at the pisiformes and hamate level as well as it is lowered during extension at the pisiformes level. This might explain the rise in carpal tunnel pressure and thus the consecutive negative influence on the median nerve. Proximal swelling, distal flattening and increased signal intensity of the median nerve as well as the palmar bulging of the flexor retinaculum at the level of the hook of the hamate and at the level of the pisiformes were significantly higher in patients with carpal tunnel syndrome than in normal volunteers (from p < 0.05 to p < 0.001). In post-operative follow-up examinations of 13 patients with no clinic symptoms the distal flattening of the median nerve normalized in 94% within 3 months. The increased signal of the median nerve on T2-weighted images decreased postoperatively in 2/3 of the patients, whereas the motor latency of the median nerve recovered only in 39% of our patients who had 100% partial or complete clinical benefit. These findings imply that postoperative imaging may be helpful for evaluating the success or failure of surgical treatment.

Adult↗

Alcohol and drug abuse in burn injuries.

Two studies are described in this paper. In the first study 225 acutely, severely burned patients were retrospectively investigated as to admission blood alcohol level and history of chronic alcohol abuse. The influence of further risk factors, circumstances and therapeutic data was studied, in particular the influence of gender, full-thickness burns, smoke inhalation injury, smoking, length of total and ICU stay, and suicide attempt. The 70 patients with positive blood alcohol levels on admission had a significantly higher fatality rate (31.5 per cent) in comparison with the 18.1 per cent fatality rate of patients with a negative blood alcohol level. Both groups had nearly identical mean TBSA and mean age. Chronic alcohol abuse was noted in 59 patients. These patients were found to have a higher fatality rate (31.4 per cent, 22/70) compared with that of patients without a history of chronic alcohol abuse who had an overall fatality rate of 18.1 per cent (28/155). No significant difference was found between non-intoxicated and acutely intoxicated alcoholics (31.4 vs 29.3 per cent). Our conclusion is that intake of alcohol before burn injury represents an independent risk factor. The second study was a prospective study of 16 consecutively admitted burn patients, who were evaluated for both drug and alcohol intake. Five patients had positive drug levels and five had positive alcohol levels. Five patients had a history of chronic drug and/or alcohol abuse. This incidence of alcohol and drug abuse supports the findings of our retrospective study.

Adolescent↗

Hand injuries secondary to subcutaneous illicit drug injections.

We present a retrospective analysis of 32 patients admitted over a 5-year period to a metropolitan regional trauma center with recently induced subcutaneous ("skin pop") illicit drug injectional injuries involving the hand. Cocaine derivatives were the most frequently reported illicit drug used (75%). All patients had local disease manifested by subcutaneous abscess formation, and several had regional disease (cellulitis, lymphangitis, or lymphadenopathy), but only one patient had systemic illness. Microbiological analysis revealed endogenous integumentary and oral flora sensitive to oral preparations of several antibiotic medications including cephalosporins. Primary therapy included intravenous administration of antibiotic medications in all instances and simple incision and drainage under local anesthesia in 26 patients (81%). Six patients (19%) required more radical operative therapy. All patients were hospitalized and recovered without sequelae, with preservation of hand function after follow-up evaluation, which ranged from weeks to months, except for 1 patient who required digital amputation because of necrosis. Although the issue of compliance in terms of wound and general medical care for this patient population is problematic, analysis of the data suggested that patients with illicit drug injectional injuries of the hand confined to subcutaneous regions could be effectively and safely managed in outpatient settings by simple wound care and orally administered cephalosporin medications.

Abscess↗

[Costs and long-term results of plastic surgery treatment of decubitus ulcers in paraplegic patients].

Costs and long-term results of plastic surgical procedures were evaluated in 17 paraplegics with a mean age of 39 years and Campbell-Grade 5 pressure sores. Seven sacral, nine ischial and one trochanteric ulcers were treated by myocutaneous or fasciocutaneous flaps. The mean hospitalization period was 82 days: up to 44 days in the plastic surgical department, 29 days in referring hospitals. During the follow-up period, averaging 18 (6 to 33) months, four patients suffered recurrences, all of them ischial sores. Evaluated regarding occupational resumption or duration of wheelchair mobility, eleven patients achieved full and two patients partial rehabilitation. The success rate justifies the operative procedures. Cost reduction by shortened hospitalization could be achieved through earlier transfer of patients to specialized units since preoperative preparation requires rarely more than one week and surgical relief can usually be achieved within a confined period of time. Orthopaedic deformities contributed to the majority of sores and to all recurrences.

Adult↗

[Abductor pollicis brevis muscle-plasty for therapy of radial collateral ligament rupture of the thumb base joint].

Untreated radial collateral ligament rupture of the thumb metacarpophalangeal joint may lead to an impairment of thumb function. The treatment is basically similar to ulnar ligament trauma management. Due to the rarity of this lesion, consistent guidelines for therapy have not yet been described. In contrast to fresh injuries a re-fixation of the disrupted ligament usually is not possible when chronic instability has already occurred. Following functional-anatomic considerations a dynamic joint stabilization method has been developed by transposition and thus reestablishing the functional direction of the abductor pollicis brevis muscle. Thus the physiological radial ligament vector is replaced and a functional ligament replacement is achieved through a technically simple procedure.

Collateral Ligaments↗

[Treatment of keloids and hypertrophic scars. Pilot study with intralesional Lipotalon injections].

A pilot study was conducted to establish whether intralesional injection of a microsomal corticoid, Lipotalon, would reduce the development of keloids and hypertrophic scars. Thirteen patients with 17 scars and keloids were admitted to the study. In all the patients investigated, injection of Lipotalon into the lesion led to a moderate to appreciable improvement in the hypertrophic scars and keloids. Injections of 0.5 to 4 mg Lipotalon were given, for the most part, at intervals of 4 to 6 weeks, and were oriented to the respective findings. No side effects were observed. Some of the patients received topical application of Lipotalon as adjuvant treatment to surgical scar resection. Here, too, a trend towards positive results was observed, although in one case, disordered wound healing was seen.

Adolescent↗

Cologne Burn Centre experiences with glycerol-preserved allogeneic skin: Part I: Clinical experiences and histological findings (overgraft and sandwich technique).

In an effort to improve the take of finely meshed autografts a modification of the sandwich technique, as first published by Alexander et al. (1981), was developed. In contrast to the techniques described by other authors, the wound bed is sealed with fibrin glue spray after excision of the burns. Widely meshed autografts are then covered with non-meshed (only scarcely sliced) glycerolized allograft sheets, being fixed with staples. Patients are placed on fluidized beds and are exposed without dressings from the fifth day onwards. Histologically and clinically, it can be assumed that part of the glycerolized allodermis is incorporated. During the weeks after transplantation, a creeping substitution of the allodermis by autologous tissue takes place. This would suggest a co-existence between glycerol-preserved hypo-allergenic allografts and auto-epidermis. Research on the definitive fate of allodermis in cases of sandwich grafting is continuing.

Adult↗

Cologne Burn Centre experience with glycerol-preserved allogeneic skin: Part II: Combination with autologous cultured keratinocytes.

Autologous keratinocytes cultured in vitro from skin biopsies of patients with deep partial and full skin thickness burns were grafted onto nine necrectomized wound surfaces between 17 and 25 days after injury. The cells were applied as nonconfluent single cells suspended in fibrin glue. In four wounds, this cell-fibrin suspension was used to attach an additional glycerolized allogeneic split thickness skin graft (STSG). Re-epithelialization was very rapid as demonstrated clinically and histologically. Keratinocyte grafted areas without cadaver skin overgraft showed less mechanical stability than when the keratinocyte-fibrin glue suspension was combined with allogeneic STSG. There is clinical and histological evidence that the allodermis may be partially integrated into the new skin.

Adult↗

Cultured autologous keratinocytes in fibrin glue suspension, exclusively and combined with STS-allograft (preliminary clinical and histological report of a new technique).

The use of cultured epidermal cell sheets has become a recognized method for the coverage of extensive burns. The disadvantages are a long time-lag until the cells are available, the fragility and difficult handling of the grafts, an unpredictable 'take' and extremely high costs. In three patients with deep partial and full skin thickness burns we have applied cultured autologous keratinocytes suspended in fibrin glue. In two of these patients the keratinocyte culture in the fibrin matrix (KFGS) was overgrafted with allogeneic, glycerine-preserved split thickness cadaver skin. The area thus covered ranged from 3 to 15 per cent TBSA. Cultured grafts were available between 2.5 and 3 weeks. The non-confluent cells developed a continuous epithelial layer within the 4 days until the first dressing change. Histological examination showed a stratified neoepidermis. Clinically the new skin had satisfactory stability and mechanical quality. The epidermis of the allogeneic overgrafts desquamated within a few days without signs of inflammation, but there are indications that the STS-allograft dermis is at least partly integrated into the new skin and may serve as a scaffold for the grafted cell culture. The fibrin glue matrix seems to give sufficient adherence stability to keratinocytes that are grafted in an actively proliferating state. Further advantages are the easy repetition and application, as well as a reduction in operating time and costs in these severely injured patients.

Adult↗