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Biomedical subjects

K D Wolff

Publications and source records attributed to K D Wolff.

36 records · Page 2Linked to original sources
PubMed1996

Improvement of the radial forearm donor site by prefabrication of fascial-split-thickness skin grafts.

A basic disadvantage of radial forearm flaps is the removal of skin from a functionally important and cosmetically exposed region. To minimize the donor-site morbidity of the radial forearm flap, we have thus far used a two-phase procedure for intraoral defect coverage in five patients: In a first step, a split-thickness skin graft is transplanted to the forearm fascia, which "takes" there over a period of 2 weeks. In step two, the prefabricated fascial-split-thickness skin flap can be raised with complete preservation of the forearm skin and microsurgically transplanted like a conventional radial flap. Performing this procedure, we have obtained the following results: (1) All skin grafts "took" completely on the forearm fascia. (2) Prefabricated fascial-split-thickness skin flaps could be raised without any problems, like conventional radial forearm flaps. (3) All flaps were excellently suited for defect coverage in the oral cavity as very thin and moldable grafts and "took" without any complications. (4) Tension-free primary closure of all forearm donor sites was achieved with only slight cosmetic and functional impairment.

Fasciotomy↗
PubMed1995

Isotope perfusion and infrared thermography of arterialised, venous flow-through and pedicled venous flaps.

In an experimental study on the epigastric venous system of rats, we examined three types of venous flaps with regard to their perfusion and long-term results: arterialised venous flaps, flow-through venous flaps and venous island flaps. We documented afferent and efferent blood flow with radiolabelled substances and blood distribution with infrared thermography. By measuring the surviving flap surfaces after 4 months, the relative success rate for each flap type was determined. The results show that in the chosen model the entire surface of the arterialised venous flap had a survival rate of 92.7%, the flow-through venous flap 62.4%, and the venous island flap about 31%. The venous island flaps had the worst distribution of intravenously injected 125J-Fibrinogen, and it was significantly worse in all types of venous flaps than in standard epigastric flaps; moreover, the clearance of intracutaneously injected 99mTc was the lowest in venous island flaps. The infrared thermographic study showed that the blood in the arterialised venous flaps dispersed faster and over a larger area than in flow-through venous and island flaps. Given these results, we conclude that arterialised venous flaps are the safest form of venous flaps, whereas venous island flaps carry a high risk of partial or total necrosis.

Animals↗
PubMed1995

Intraoral defect coverage with muscle flaps.

PURPOSE: This study investigated whether wound healing after the use of purely muscular flaps for intraoral defect coverage is negatively influenced by insipient muscular atrophy and the absence of a covering layer. MATERIALS AND METHODS: In an experimental study, microsurgical transplantation of muscle flaps from the anterior abdominal wall was carried out in 18 Lewis rats. A nerve anastomosis for motor reinnervation was not performed. Atrophy of the muscle flaps was determined by measuring the reduction of their size and weight after 3, 8, and 20 weeks. In the clinical part of the study, free muscle transplants from different donor regions (vastus lateralis, pectoralis major, internal oblique, and temporalis muscles) were used for defect coverage in various areas of the oral cavity. To study epithelization, punch biopsy specimens from the muscle surface were taken at periods of 2 to 4 weeks up to 6 months for histologic evaluation. Final evaluation of reconstruction results with special regard to speech, tongue mobility, mouth opening, chewing, and swallowing took place after 6 months. RESULTS: In the experimental study, average weight loss of the muscle flaps was 67% after 20 weeks, and the remaining surface area was 71%. The number of myocytes was only about 30% compared with control muscles, and parts of the flap appeared as a thin fibrous membrane. Clinically, this atrophy led to restricted mobility in such areas as the floor of the mouth, the buccal plane, and the tongue. Muscle flaps covering solid structures such as bones or reconstruction plates adapted well to the transplant bed, and the atrophy of the muscle led to no constriction of the surrounding tissue. Atrophy also did not have a negative effect when muscle flaps were placed in the region of the pharyngeal wall. Epithelization started from the edges after 2 weeks and was concluded after 8 weeks in all transplants if no additional radiation was performed. The muscle tissue was sufficiently resistant so that infection, fistulization, and necrosis did not occur. CONCLUSIONS: Muscle flaps undergo considerable atrophy with a cicatricial transformation and reduction of flexibility. Despite these disadvantages they can be used in the hard palate, the alveolar crest, and in the pharyngeal wall without causing functional restriction. Because of constriction of the surrounding tissues, mobile areas such as the buccal plane, the floor of the mouth, and the tongue are not suitable as sites for muscle transplants.

Abdominal Muscles↗
PubMed1995

The osteoseptocutaneous or purely septocutaneous peroneal flap with a supramalleolar skin paddle.

There are many indications for using the peroneal flap in maxillofacial reconstructive surgery, either as a cutaneous flap or combined with a fibula segment. According to the results of our anatomic study and clinical experience with 14 patients, the supramalleolar segment is especially suitable as donor region because the highest density of septocutaneous perforating vessels exists here; hence, the preparation of a long vascular pedicle is possible. The donor site leaves an acceptable defect with appropriate patient selection.

Adult↗
PubMed1995

Three years of experience with the free vastus lateralis flap: an analysis of 30 consecutive reconstructions in maxillofacial surgery.

Free vastus lateralis flaps for maxillofacial reconstruction were used in 30 patients. On the basis of its anatomy, this flap can be inserted as a musculocutaneous or musculofascial transplant in slim or normal-weight patients if extensive defects exist. The microvascular transfer is facilitated and accelerated by the long and high-caliber vascular pedicle and flap raising, which can be performed at the same time as tumor resection. We see indications for the musculocutaneous transplant in almost all sections of the oral cavity, particularly for tongue reconstruction; the vastus lateralis flap can be inserted in a purely muscular form for defect coverage on the scalp in connection with split skin. The donor defect is minimal functionally and aesthetically, and the success rate is approximately 90% for all flap transfers.

Adult↗
PubMed1993

Nerve reconstruction with glycerol-preserved allogenic grafts in the rat.

A variety of materials have been evaluated as potential nerve grafts. To date, none has been shown to be consistently equal with regard to functional outcome when compared to standard autogenous nerve grafts. In this study, nerves stored in glycerol were evaluated for their peripheral nerve regenerative capacity. Femoral nerves were harvested from Fischer rats and stored for a minimum of 100 days in 98% glycerol at 4 degrees C. They were grafted into femoral nerve gaps of Lewis rats. After 3 months, histologic, electrophysiologic, and morphometric (axon diameter) analyses revealed less regenerative response than nerve gaps grafted with fresh, syngeneic controls. The differences disappeared by 6 months, although neither graft technique achieved recovery comparable to unoperated nerves. Immunohistochemical evaluation demonstrated a modest immune response at 3 months, which subsided by 6 months. These findings are encouraging for the development of glycerol-preserved nerve graft banking.

Action Potentials↗
PubMed1993

The supramalleolar flap based on septocutaneous perforators from the peroneal vessels for intraoral soft tissue replacement.

In cadavers the septocutaneous perforating vessels branching off the distal segment of the peroneal artery were studied. An area of skin approximately 7 x 12 cm above the ankle was noted to be perfused by these and intraoral defects in 8 patients have been repaired using the supramalleolar flap as a variation of the peroneal flap developed by Yoshimura. Owing to its thinness and the long and wide vascular pedicle, the flap is particularly suitable for reconstructing mobile parts of the oral cavity, and in selected cases may be considered as an alternative to a radial flap.

Aged↗
PubMed1993

Non-invasive neuromagnetic monitoring of nerve and muscle injury currents.

Structural damage inflicted on membranes of excitable cells may evoke quasi-DC injury currents driven by the transmembrane resting potential gradient. In contrast to the usually invasive electrophysiological approaches, superconducting quantum interference devices (SQUIDs) measure the concomitant weak biomagnetic fields non-invasively as is shown here for acutely excised rat nerves or muscles. Analysis of the field distributions showed slowly decaying equivalent current dipole moments in the nanoampmeter range as generated by microamp nerve injury currents extending intra-axonally over millimeter distances. The geometric and kinetic parameters of this experimental design may allow in vivo recordings in human patients.

Animals↗
PubMed1993

Ischemia tolerance of free-muscle flaps: an NMR-spectroscopic study in the rat.

The ischemia tolerance of free-muscle flaps was investigated in the rat by orthotopic and syngeneic transplantation of muscle flaps measuring 4 x 2.5 cm. The effects of ischemia with a maximal duration of 7 hours on the raised flaps and of anoxia caused by occlusion of the flap vessels were studied for the first time using 31P-spectroscopy. Energy metabolism was found to recover fast after 3 hours of ischemia, whereas a duration of 4 hours led to severe, only slowly reversible changes. Longer periods of ischemia resulted in a complete loss of energy reserves (PCr) and weaker ATP signal. The complete absence of ATP and a pH value under 6 indicated irreversible muscular damage.

Abdominal Muscles↗
PubMed1992

Applications of the lateral vastus muscle flap.

The lateral vastus muscle flap has the potential to become one of the most appropriate free flaps for reconstructive surgery in the oral maxillofacial area in selected cases. The flap is relatively easy to harvest and gives rise to little donor site morbidity. The quality of the large diameter vessels allows for relatively easy microsurgical anastomosis. Nerve anastomosis is possible, which makes it extremely suitable for tongue reconstruction.

Adult↗
PubMed1992

Functional aspects of free muscle transplantation: atrophy, reinnervation, and metabolism.

The atrophy, reinnervation, and metabolism of free muscle flaps were studied in a rat model, by syngeneic and orthotopic transplantation of abdominal wall muscle flaps with neurovascular anastomoses. The three parameters were examined at different time periods, using electrophysiologic and 31-P-spectroscopic measurements. Results show that a certain degree of atrophy (one-fifth of the original volume) must be expected, even when new axons grow throughout the nerve. This is explained by the early reduction of flap metabolism, leading to a loss of parenchyma until neuromuscular conduction is restored. As the maximum duration of ischemia is 2 hr, muscular damage due to reduced metabolism was not produced.

Abdominal Muscles↗
PubMed1992

The free vastus lateralis flap: an anatomic study with case reports.

The suitability of the thigh as a donor site for a new free flap was examined in 100 cadavers. It was found that the vastus lateralis muscle can be used to form a myocutaneous or fasciomuscular flap, the raising of which causes no technical problems and leads to no functional and only minor aesthetic impairments. Depending on the muscle segment from which the flap is raised, a neurovascular pedicle measuring between 8 and 20 cm with a diameter of 2 to 2.5 mm (artery) or 2.5 to 4 mm (vein) can be formed. The skin island in the myocutaneous flap measures on average 8 x 16 cm and is located above the middle portion of the muscle. The diameter of the supplying perforator vessel is between 0.7 and 1.2 mm. The flap can be raised parallel to head and neck surgery and applied as a myocutaneous flap for coverage of extensive or perforating defects or intraorally as a fasciomuscular flap.

Adult↗
PubMed1990

Vessel preservation with glycerol: an experimental study in rats.

Arterial and venous allografts (aorta and femoral vein or artery) of Sprague-Dawley rats were preserved with glycerol (98%) or by lyophilization and subsequently implanted in Wistar rats. The grafts were removed for histologic examination of vessel patency on days 1, 30, 60, and 100 postoperatively. Whereas the glycerol-preserved vessels exhibited a high patency, the results obtained with the lyophilized vessels were less favorable. Lyophilized veins could not be successfully implanted.

Animals↗
PubMed1990

[The value of 3D-CT in maxillary surgical diagnosis and therapy planning].

In 25 patients in whom oral surgery was required, we examined what additional information can be obtained via three-dimensional CT compared with conventional transverse CT scans. We showed that D-3 CT facilitated the spatial orientation by complex osseous destructions. Better therapy planning and postoperative control was therefore feasible. However, CT diagnosis continued to be based on transverse scans.

Aged↗
PubMedDate not supplied

[Reliability and risks of angiography in microsurgery].

Angiography is a reliable method for imaging the deep iliac circumflex, the inferior epigastric and the external pudendal artery. However, 10-30% of all arteriograms fail to visualize the superficial iliac circumflex, the superficial epigastric artery, and the muscular branch, whose lumina are generally 1 mm smaller at their origins. The reason for this may be associated with the cannulization of the vascular lumen for injection of the contrast medium (see below): while the cannula could be easily inserted in the larger vessels mentioned first, cannulation was occasionally complicated by calcareous deposits in the femoral artery which narrowed the lumen of the latter arteries at their origins. In smaller vessels angiography provides no conclusive information on degenerative alterations. Angiography performed immediately before microvascular anastomosing highly jeopardized the vessel's patency. Remnants of the highly viscous and sticky contrast medium that remain attached to the vascular wall complicate the technical procedure of anastomosing. In a free flap with its numerous anastomoses cut off, the medium's high viscosity may result in stasis first in the capillaries and ultimately in the trunk. According to the present results preoperative angiography is a useful method for treatment planning in microvascular surgery. However we should call for the routine application of this technique only in those cases, where the host or donor site has been changed in a previous surgical intervention. To ensure complete washout of the contrast medium, there should be an interval of at least 2 days between angiography and surgery.

Abdominal Muscles↗