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Biomedical subjects

L S Levin

Publications and source records attributed to L S Levin.

At least 19 recordsLinked to original sources
PubMed2006

[Literature and own strategies concerning soft-tissue reconstruction and exposed osteosynthetic hardware].

BACKGROUND: In the event of exposed hardware from reconstructive surgery, it must be decided whether to retain or remove it prior to plastic surgical soft-tissue reconstruction to ensure long-term freedom from infection and stable wound closure. MATERIAL AND METHODS: Treatment options and results in the literature are reviewed. A treatment algorithm is proposed under consideration of our personal experience. RESULTS AND CONCLUSION: Hardware used in spine surgery is commonly left in situ until bony consolidation has been achieved. The indications for hardware removal depend on length of exposure or infection, implant failure, and location. Osteosynthetic devices in the extremities may be removed and replaced by external fixators or immobilisation. Removal of prostheses requires complex second-stage reimplantation or arthrodesis. A treatment algorithm is suggested that might ease the decision whether exposed hardware can remain or requires removal before reconstruction of soft-tissue defects.

Algorithms↗
PubMed2006

[The infragluteal perforator flap].

PURPOSE: Pressure sores of the ischial tuberosities are mostly covered with fascio- or myocutaneous flaps of the posterior thigh. In doing so, vascular territories of adjacent flaps are violated, which are not available any more in case of ulcer recurrences. In consideration of the high recurrence rates of pressure sores in paraplegics, we developed an infragluteal perforator flap that spares adjacent vascular territories. PATIENTS/MATERIAL AND METHOD: Infragluteal perforator flaps were dissected in five fresh human cadavers to investigate the anatomic relations of the cutaneous branches of the inferior gluteal artery and the inferior clunial nerves and to define the anatomic landmarks for clinical application of an innervated flap. In six paraplegic patients with primary (5/6) and secondary (1/6) pressure sores of the ischial tuberosity, infragluteal perforator flaps were used for wound coverage. The donor defect was closed primarily and postoperative care and patient mobilisation followed a standardised protocol. RESULTS: In eleven infragluteal perforator flaps that were dissected in cadavers and patients, we found one or two cutaneous branches of the descending branch of the inferior gluteal artery at the lower border of the gluteus maximus muscle that supplied the infragluteal skin. Infragluteal perforator flaps could be harvested on these perforator vessels and transferred to the ischial defects without tension due to the excellent mobility of the skin island. The descending branch of the inferior gluteal artery could be spared in all cases for future flaps. In one patient with multiple recurrences of an ischial pressure sore flap necrosis occurred due to venous congestion. The other five infragluteal perforator flaps healed without complications. CONCLUSION: The infragluteal perforator flap is suitable for the closure of pressure sores of the ischial tuberosities and can be used as a sensitised flap by inclusion of the inferior clunial nerves. Compared to traditional pedicled flaps of the posterior thigh, the infragluteal perforator flap reduces donor site morbidity and spares the vascular territories of adjacent flaps for future recurrent ulcers.

Adult↗
PubMed2004

[Free fibula transfer. Analysis of 76 consecutive microsurgical procedures and review of the literature].

Since its introduction by Taylor in 1975, microvascular free fibula transfer has become the gold standard in osseous reconstructions requiring vascularized bone transfer. Various modifications of the free fibula have been described in the literature. We reviewed a series of 76 free vascularized fibula transfers during a 7-year period. Data was retrospectively analyzed with respect to type of procedure and outcome, general surgical complications, and flap-related (specific) complications. Of all 76 free fibula flaps, 47 cases healed uneventfully (62%). Interestingly, 53% of all extremity reconstruction cases had at least one of the above complications, whereas in maxillofacial cases the complication rate was only 25%. Complete osseous consolidation at the time of evaluation was confirmed in 58 patients (76%). Complete flap failure occurred in four patients (5%). The complication rates reflect the complexity of the procedures and appear strongly related to the underlying disease and predisposing medical risk factors. Time will tell if advances, e.g., in the field of tissue engineering, will eventually replace autologous vascularized bone transfer.

Adolescent↗
PubMed2004

Distraction lengthening of thumb metacarpal.

The purpose of this retrospective study was to evaluate the clinical outcome of distraction lengthening of the thumb metacarpal without bone grafting in seven patients with traumatic thumb loss. The distraction was stopped after 57 (range, 42 to 91) days, giving a median lengthening of 28 (range, 20-36)mm. It took an average of 155 (range, 118-196) days for bony consolidation to occur. The mean pinch power was 72% of that of the uninjured hand. The two-point discrimination on the pulp of the reconstructed thumb was 10 (range, 8-12)mm. There were no major complications.

Adult↗
PubMed2003

[Role of a sensory innervated plantar fillet free flap for reconstruction of sacral pressure sores in paraplegic patients. Last resort for reconstruction of sacral pressure sores in paraplegics].

Sensory denervation is the key factor for the high rate of recurrent sacral pressure sores in paraplegic patients. This paper summarizes the results after reconstruction of recurrent sacral pressure sores using a sensory innervated plantar fillet free flap. Five plantar fillet free flaps were utilized for defect reconstruction of sacral pressure sores in five male patients during a 9-year period (1989-1998). Data were analyzed retrospectively. Patients'age ranged between 32 and 51 years. The level of spinal cord injury was between T10 and L1. The average defect size was 20 x 16 cm. All flaps were microsurgical free tissue transfers. The posterior tibial nerve was coapted to two intercostal nerves from above the spinal cord injury level. All patients developed sensation within 3-6 months. A stable sensate coverage was achieved in each case. The data show that the concept of a sensory innervated plantar fillet free flap may facilitate defect reconstruction in most complex or even seemingly hopeless cases.

Adult↗
PubMed2002

[Symmetrical peripheral gangrene of unknown etiology].

We describe the case of a 19-year-old female patient who presented with acute symmetrical peripheral gangrene (SPG), including all fingers and toes. Further diagnostic work-up did not reveal any underlying condition other than a non-specific transient cryoglobulinemia. Despite immediate anticoagulopathic and anti-inflammatory treatment, all fingers and toes had to be amputated.

Adult↗
PubMed2002

[Current perspectives of orthogonal polarization spectral imaging in plastic surgery].

The technology of Orthogonal Polarization Spectral Imaging (OPSI), patented in the United States in 1999, has been heralded as an alternative to conventional intravital microscopy for several reasons, including ease of application and ability to perform continued observations. In the following examples, OPSI was applied to reconstructive plastic surgery. Two experimental and one clinical model are presented. Currently, the image quality does not allow a qualitative analysis of the microvasculature. The data analysis of images remains inconclusive. However, a technically modified version with improved image resolution and software could become a valuable experimental as well as clinical tool in the field of reconstructive plastic surgery in the future.

Animals↗
PubMed2002

[The use of fillet flaps in upper extremity and shoulder reconstruction].

Extensive soft tissue defects of the upper extremities were reconstructed with major fillet flaps in nine patients over a 5-year period at two institutions. Etiologies included trauma and tumor resection. Defect locations were the shoulder ( n=3), combined defects of the shoulder plus neck, arm or chest wall ( n=4) as well as one upper arm and one forearm defect. Seven of nine flaps required microsurgical free tissue transfer. Fillet flaps harvested from amputated parts represent the "spare part" concept, providing coverage of defects without additional donor site morbidity. Unlike the classic "spare part" fillet flap concept, the partial or complete conversion of an anatomically intact arm was performed for the coverage of large defects, especially for tumor reconstruction, in this series. Fillets flaps facilitate reconstruction in difficult and complex cases. Major fillet flaps represent a valuable option for reconstruction in the upper extremities with either pedicled or free tissue transfers involving extensive tissue defects.

Adult↗
PubMed2002

[Endoscopically controlled stabilization of humerus shaft fractures. The endoscope as an aid in minimally invasive osteosynthesis].

This study describes the anatomical basis of direct visualization of the radial nerve and of fracture reduction in humeral shaft nailing and reports first clinical results. Fourteen cadavers were random selected and dissected in order to determine the exact course of the radial nerve in relationship to anatomical landmarks. In individuals with a total humeral length between 25-33 cm the radial nerve was found to cross the humeral shaft exactly in the middle of the long axis of the humeral shaft. The average distance from the lateral epicondyle to the point were the radial nerve penetrates the lateral intermuscular septum was 11.9 +/- 1.0 cm, the distance from the posterior tip of the acromion to the crossing of the nerve with the medial border of the humeral shaft was 12.9 +/- 1.5 cm. Using these landmarks in six clinical cases fracture reduction, visualization of the radial nerve and intramedullary nailing could be achieved with endoscopic control. There were no surgical complications such as secondary radial nerve palsy, hematomas or wound healing problems. With the use of the endoscope the number of secondary radial nerve palsies associated with intramedullary humeral shaft nailing might be reduced in the future.

Adult↗
PubMed2002

Ipsilateral free fibula transfer for reconstruction of a segmental femoral-shaft defect.

We describe an ipsilateral free fibula transfer for segmental femur reconstruction with venous interpositional grafts. Preparation and use of vessels at the recipient site for microvascular anastomosis is avoided. This represents a valuable modification of previously reported techniques, and should be considered as an alternative to conventional techniques, which regularly require more dissection at the reconstructive site.

Adult↗
PubMed2002

[Fasciocutaneous radial artery perforator vessels - an anatomic study].

PURPOSE/BACKGROUND: Distal and proximal pedicled forearm flaps that are nourished by radial perforator vessels have been described. These flaps spare the radial artery during flap harvest. The question is, whether it is possible to raise individual free fasciocutaneous radial perforator flaps. METHOD AND MATERIAL: The number, external vessel diameter, and distribution of fasciocutaneous radial perforator vessels were investigated on 20 fresh cadaver arms. All specimen were then treated with the Spalteholz technique to demonstrate the arborizing of the perforator vessels. RESULTS: There was an average of 12 (range 9 to 16) fasciocutaneous perforator vessels per radial artery. The most proximal perforator vessel had an external diameter of 0.8 (range 0.5 to 1.0) mm, the others were measured smaller then 0.5 mm. There was a rich network of anastomoses at the level of the fascia up to the level of the subdermal plexus. CONCLUSIONS: The anatomic basis of the proximally and distally based radial perforator flaps was confirmed. Free flaps based exclusively on fasciocutaneous radial perforators would require supra-microsurgical skills due to the small vessel diameter. For practical reason it seems to be advisable to include parts of the radial artery into such a flap design.

Humans↗
PubMed2002

Treatment of segmental defects of the humerus with an osteoseptocutaneous fibular transplant.

BACKGROUND: There are limited reconstructive options for the treatment of segmental bone defects of the upper extremity that are >6 cm in length, especially those that are associated with soft-tissue defects. The purpose of the present review was to report on our experience with fifteen patients who received an osteoseptocutaneous fibular transplant for reconstruction of a humeral defect. METHODS: The study cohort included eight male patients and seven female patients with an average age of forty-one years. The indications for the procedure included segmental nonunion (nine patients), a gunshot wound (three), a defect at the site of a tumor resection (two), and failure of an allograft-prosthesis reconstruction (one). The fibular graft was fixed by means of intramedullary impaction in eleven patients, was used as an onlay graft in three, and was used as a strut between the intact diaphysis and the humeral head in one. RESULTS: The average length of the segmental humeral defect was 9.3 cm. The average length of the fibular graft was 16.1 cm, and the average length and width of the skin paddle were 8.1 and 4.5 cm. The average duration of follow-up was twenty-four months. Three patients had venous thrombosis and underwent a successful revision of the anastomosis. Four patients had early failure of graft fixation. Three patients had a fracture of the fibular graft within the first year postoperatively. All but one of these latter seven patients were successfully treated with open reduction, internal fixation, and additional bone-grafting. One patient with an infection at the site of a nonunion and signs of graft resorption required a second fibular transplant. CONCLUSIONS: The osteoseptocutaneous fibular transplant is an effective treatment for combined segmental osseous and soft-tissue defects of the arm. However, the application of this technique to the arm is more complex than application to the forearm and is associated with a higher rate of complications.

Adolescent↗
PubMed2001

Lower extremity microsurgical reconstruction.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the indications for the use of free-tissue transfer in lower extremity reconstruction. 2. Understand modalities to enhance the healing and care of soft tissue and bone before free-tissue transfer. 3. Understand the lower extremity reconstructive ladder and the place of free-tissue transfer on the ladder. 4. Understand the specific principles of leg, foot, and ankle reconstruction. 5. Understand the factors that influence the decision to perform an immediate versus a delayed reconstruction. Free-tissue transfer using microsurgical techniques is now routine for the salvage of traumatized lower extremities. Indications for microvascular tissue transplantation for lower extremity reconstruction include high-energy injuries, most middle and distal-third tibial wounds, radiation wounds, osteomyelitis, nonunions, and tumor reconstruction. The authors discuss the techniques and indications for lower extremity reconstruction.

Bone Neoplasms↗
PubMed2001

Long- and short-term effects of biological hydrogels on capsule microvascular density around implants in rats.

Fibrous capsule formation around implants can inhibit solute exchange between implantable devices and the circulation. Parylene-n coated polycarbonate disks surrounded with growth factor reduced Matrigel (MG) or several gelatin-based matrices were implanted intramuscularly into rats for 21 or 50 days. MG supplemented with vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) increased capsule microvascular density at 21 days (p < 0.05) when compared to bare parylene-coated polycarbonate disks (control). The increased microvascular density around VEGF- and bFGF-treated implants regressed by 50 days and was no longer significantly different from controls. The microvascular density induced by the gelatin-based matrices was not significantly different from controls at 21 days, but was increased at 50 days (p < 0.05), suggesting a slower, long-term effect. Disks treated with MG and gelatin-based matrices had thinner capsules at 21 days (p < 0.05). By 50 days, the capsule thicknesses around these implants were no longer statistically thinner than controls. The capsule thickness around implants treated with VEGF, bFGF, and essential gelatin-based matrix was thinner than controls at 50 days (p < 0.05). These results indicate that it is possible to increase functional microvascular density within fibrous capsules using angiogenic growth factors and gelatin-based matrices. However, this effect may be short-lived, requiring chronic administration of growth factors.

Animals↗
PubMed2001

Soft tissue coverage options for ankle wounds.

Soft tissue deficiencies of the ankle are caused by several mechanisms, such as trauma, tumor, and infection. Compounding the reconstructive problems is that soft tissue problems often present in patients who have underlying diseases such as peripheral vascular disease, diabetes or both. For example, a 65-year-old person with diabetes who smokes two packs of cigarettes per day sustains an ankle fracture. After undergoing open reduction and internal fixation of the fracture, there is subsequent wound behiscence over the patient's fibular plate. The wound edges cannot be reapproximated, and there is loss of soft tissue. What should treatment be for this soft tissue problem? Another example is a 45-year-old rheumatoid patient who takes 20 mg of steroids a day and undergoes posterior tibial tendon repair after rupture. One month after surgery, the surgical wound dehisces, resulting in exposure of the tendon repair. What is the approach for adequate and effective soft tissue treatment? The purpose of this article is to address such complex problems and to provide an algorithm for soft tissue reconstruction of the ankle.

Algorithms↗
PubMed2001

Laser Doppler flowmeter monitoring of free-tissue transfers: blood flow in normal and complicated cases.

In this article, laser Doppler flowmeter (LDF) monitoring of blood flow in 94 free flaps is summarized. Seventy-six patients had uneventful postoperative courses, and 18 patients developed postoperative complications, with a salvage rate of 88 percent. Except for one case, the flowmeter identified developing complications before clear clinical indices appeared, and in two cases it was the only indication of vascular compromise of the flap. On the basis of the data obtained, the ranges of absolute flow values in different types of uncomplicated flaps are reported, along with their temporal pattern of flow. Decrease inflow pattern may be an early indicator of a developing perfusion disturbance. On the basis of LDF readings, the following classifications of free-flap blood flow are suggested. (1) If the flow is within or slightly above the established range, then normal diligence in observation is justified. If the flow is well above the normal range, artifacts that could falsely elevate readings should be investigated. (2) If the flow is somewhat below the established range, then a modest increase in observation is warranted (alert level 1). (3) If the relative flow falls to 50 percent of the initial flow of that flap and remains at that level for 30 minutes or longer, then more aggressive flap observation is indicated (alert level 2). (4) If the flow is below 0.4 LDF units for 30 minutes, then aggressive clinical observation should be performed (alert level 3, or "red alert") and exploration should be strongly considered. Falsely elevated measurements can be caused by vibration, motion of the probe or tissue, or location of the probe over a macroscopic blood vessel. False low readings are quite rare but can result from partial probe detachment from the flap or coagulum accumulating on the probe. Once artifacts are ruled out, LDF readings have a high level of credibility and, in the authors' experience, significantly improve salvage rates.

Abdominal Muscles↗
PubMed2001

Primary and secondary microvascular reconstruction of the upper extremity.

Tissue defects of the upper extremity may result from trauma, tumor resection, infection, and congenital malformation. Restoration of anatomy and functional integrity may require microsurgical free flap transfer for coverage of bones, nerves, blood vessels, or tendons. Microsurgical tissue transfer also may be required prior to secondary reconstruction, such as tendon transfers or nerve or bone grafts. This article addresses indications for upper extremity reconstruction using microsurgical tissue transfer flap selection and strategies including primary and secondary reconstruction.

Amputation, Traumatic↗