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Biomedical subjects

M Lanzetta

Publications and source records attributed to M Lanzetta.

At least 37 records · Page 2Linked to original sources
PubMed1999

Free-flap transfer with a synthetic arterial pedicle.

In this study, a unilateral epigastric free flap was raised in 12 rabbits. After the arterial portion of the flap (the superficial femoral artery) was replaced by a 1-cm-long polytetrafluoroethylene graft with an internal diameter of 1 mm, the flap was revascularized by two conventional microvascular end-to-end anastomoses (graft to artery and vein to vein). At 3 weeks, all flaps were raised again and the patency of the polytetrafluoroethylene grafts was checked. All grafts, including the proximal and distal anastomoses, were harvested and processed for light and electron microscopy. All grafts remained patient, and all flaps survived the period of 3 weeks. At reexploration, the graft was completely covered with connective tissue. Light and scanning electron microscopy evaluation showed that the internal surface of the graft was covered by a fibrin layer, and that the ingrowth of neoendothelium had just started from both anastomotic sites. The use of small-diameter polytetrafluoroethylene grafts in a rabbit free-flap model was demonstrated to be a reliable alternative for pedicle elongation.

Animals↗
PubMed1999

Sutureless microvascular anastomoses by a biodegradable laser-activated solid protein solder.

A new sutureless technique to successfully anastomose the abdominal aorta of rats (1.3 mm in diameter) by using a fully biodegradable, laser-activated protein solder is presented. A total of 90 rats were divided into two groups randomly. In group one, the anastomoses were performed by using conventional microsuturing technique, whereas in group two, the anastomoses were performed by using a new laser welding technique. In addition, each of the two groups were divided into five subgroups and evaluated at different follow-up periods (10 minutes, 1 hour, 1 day, 1 week, and 6 weeks). At these intervals, the anastomoses were evaluated for patency and tensile strength. Three anastomoses in each subgroup were processed for light and electron microscopy. All anastomoses were found to be patent. The mean clamp time of the anastomoses performed with conventional suturing was 20.6 minutes compared with 7.2 minutes for the laser-activated welded anastomoses (p < 0.001). The strain measurements showed a stronger mechanical bond of the sutured anastomoses in the initial phase. However, at 6 weeks the tensile strength of the laser-welded anastomoses was higher compared with the conventional suture technique. Histologic evaluations revealed a near complete resorption of the solder after 6 weeks. The junction site of the vessel ends cannot be determined on the luminal side of the artery. In conclusion, a resorbable protein used as a solder, activated by a diode laser, can provide a reliable, safe, and rapid arterial anastomosis, which could be performed by any microsurgeon faster than conventional suturing after a short learning curve.

Anastomosis, Surgical↗
PubMed1998

Laser welding of vas deferens in rodents: initial experience with fluid solders.

This study evaluates the use of sutureless laser welding for vasovasostomy. In 14 rodents, the left vas deferens underwent vasovasostomy using an albumin-based solder applied to the adventitia of the vas deferens. The solder contained the dye, indocyanine green, to allow selective absorption and denaturation by a fiber-coupled 800-nm diode laser. The right vas deferens served as a control, receiving conventional layered microsurgical repair. We used a removable 4/0 nylon stent and microclamps to appose the vas deferens during repair, with no need for stay sutures. The mean time to perform laser solder repair (23.5 min) and conventional repair (23.3 min) were not significantly different (P=0.91). However, examination after 8 weeks showed that granuloma formation (G) and patency (P) rates for the conventional suture technique (G, 14%; P, 93%) were significantly better than observed for the laser solder technique (G, 57%; P, 50%).

Albumins↗
PubMed1998

Intraosseous repair of the inferior alveolar nerve in rats: an experimental model.

A reliable method of exposure of the inferior alveolar nerve in Wistar rats has been developed, to allow intraosseous repair with two microsurgical techniques under halothane inhalational anaesthesia. The microsuturing technique involves anastomosis with 10-0 nylon sutures; a laser-weld technique uses an albumin-based solder containing indocyanine green, plus an infrared (810 nm wavelength) diode laser Seven animals had left inferior alveolar nerve repairs performed with the microsuture and laser-weld techniques. Controls were provided by unoperated nerves in the repaired cases. Histochemical analysis was performed utilizing neuron counts and horseradish peroxidase tracer (HRP) uptake in the mandibular division of the trigeminal ganglion, following sacrifice and staining of frozen sections with cresyl violet and diaminobenzidene. The results of this analysis showed similar mean neuron counts and mean HRP uptake by neurons for the unoperated controls and both microsuture and laser-weld groups. This new technique of intraosseous exposure of the inferior alveolar nerve in rats is described. It allows reliable and reproducible microsurgical repairs using both microsuture and laser-weld techniques.

Animals↗
PubMed1997

Resurfacing of the donor defect after wrap-around toe transfer with a free lateral forearm flap.

In thumb reconstruction, the wrap-around free flap has many advantages; however, delayed wound healing, pain, and skin ulcerations at the donor site can be a problem. In 5 patients, a free lateral forearm fasciocutaneous flap was successfully used for immediate resurfacing of the donor defect of the big toe during wrap-around procedures. This flap was selected after preliminary anatomic studies that showed that it could be safely raised if based on the anterior terminal division of the posterior radial collateral artery. The average follow-up period was 2 years. The time required for healing of the great-toe defect was less than 1 month. All patients were satisfied with the outcome of the procedure. The skin of this flap is very pliable and thin, and the subcutaneous tissue is about half the thickness of that of the lateral arm flap. This technique is especially indicated for closure of moderate to big skin defects at the great-toe level, whenever a larger than usual amount of skin is required, during wrap-around procedures for thumb reconstruction.

Adolescent↗
PubMed1997

The lateral forearm flap: an anatomic study.

The anatomy of the lateral forearm flap has been studied in 12 fresh cadaver arms with methylene blue and latex injections and arteriography. The posterior radial collateral artery was found to divide constantly into two terminal branches, an anterior and a posterior division. The anterior division is the nutrient vessel of the flap. This artery extends significantly beyond the lateral epicondyle of the elbow into the lateral aspect of the forearm (range 13 to 18 cm, average 15 cm). This allows raising a fasciocutaneous flap in the proximal forearm with a much longer vascular pedicle than the classic lateral arm flap. Other advantages include very thin skin and subcutaneous tissue and less sensory deficit at the donor site. Based on these results, this newly designed lateral forearm flap has been used in 13 clinical cases. Its main indications are whenever soft, thin, pliable skin is needed for small to moderate-sized defects.

Cadaver↗
PubMed1996

Fibroblast growth factor pretreatment of 1-mm PTFE grafts.

When using microvascular polytetrafluoroethylene (PTFE) vascular grafts, the best results in terms of patency rate and neoendothelialization are obtained with prostheses with thin walls and long fibril length (i.e., 90 microm). A complete internal neoendothelial lining is usually achieved at 12 weeks after implantation. Clinically, this period can be too long. In this study, 1-mm internal diameter PTFE prostheses with optimal physical characteristics were pretreated with basic fibroblast growth factor in fibrin glue, a potent endothelial cell mitogen, and chemoattractant. Rate, speed, extent, quality, and origin of neoendothelium were compared with two control groups, using Evans Blue dye, immunohistochemical localization of factor VIII von Willebrand factor protein, and scanning electron microscopy. Prostheses (8 mm long) were implanted in the infrarenal rat aorta and harvested after 3 weeks. In treated grafts, the amount of endothelial regeneration was greater than in untreated grafts (75% of the internal surface compared with 30%). However, patency rate in the experimental group was lower than in the control groups. This study provides new data on neoendothelial regeneration in small-diameter PTFE grafts.

Anastomosis, Surgical↗
PubMed1996

Assessment of nerve ultrastructure by fibre-optic confocal microscopy.

Fibre-optic technology combined with confocality produces a microscope capable of optical thin sectioning. In this original study, tibial nerves have been stained in a rat model with a vital dye, 4-(4-diethylaminostyryl)-N-methylpyridinium iodide, and analysed by fibre-optic confocal microscopy to produce detailed images of nerve ultrastructure. Schwann cells, nodes of Ranvier and longitudinal myelinated sheaths enclosing axons were clearly visible. Single axons appeared as brightly staining longitudinal structures. This allowed easy tracing of multiple signal axons within the nerve tissue. An accurate measurement of internodal lengths was easily accomplished. This technique is comparable to current histological techniques, but does not require biopsy, thin sectioning or tissue fixing. This study offers a standard for further in vivo microscopy, including the possibility of monitoring the progression of nerve regeneration following microsurgical neurorraphy.

Animals↗
PubMed1996

Atraumatic tendon handling during tendon repair.

Two techniques are presented for atraumatic handling of tendon ends during repair of flexor and extensor tendons. If the tendon is cleanly transected, the suture is carried out by holding the tendon in nerve holding forceps. If debridement is needed, a slice is partly cut and used to handle the tendon; the slice is then cut off and discarded.

Humans↗
PubMed1996

Spontaneous thrombosis of palmar digital veins.

Five cases of spontaneous thrombosis of a palmar digital vein are presented. The patients, all female, complained of a tender and unsightly lump over the digital palmar surface at the proximal interphalangeal joint level. Two fingers were affected in one patient. None could recall any history of trauma. In four cases a surgical excision was carried out. Histology confirmed the intraoperative findings of thrombosis of a superficial digital vein in every case. All patients are free from recurrence at a mean follow-up of 2.5 years.

Adult↗
PubMed1996

Diagnostic ultrasound of the hand and wrist.

To assess the efficacy, role, and limitations of diagnostic ultrasound in the hand and wrist, the results of 98 examinations performed for a variety of surgical conditions were retrospectively analyzed. Ultrasound was shown to be reliable in evaluating radiolucent foreign body, tendon rupture versus tendon adhesion, tendinitis, peritendinitis, and ganglion cyst (specificity, 1; positive predictive value, 1). A correct suggestion of soft tissue mass histology was offered in six of eight operated cases. Tumor size and extent was accurately assessed in all but one case. The observed limitation of ultrasound was a small false negative rate in each category, which related to a variety of factors, including operator dependence, resolution threshold in the submillimeter range, image degradation due to postoperative edema, a narrow field of view, and one instance of indiscrete tumor margination. More work is needed to determine the role (if any) of ultrasound in the evaluation of peripheral nerve, triangular fibrocartilage, dorsal carpal ligament, and bone pathology.

Adolescent↗
PubMed1996

Scanning electron microscopy evaluation of endothelial regeneration in 1-mm PTFE prostheses.

This study documents the developmental stages of neoendothelium regeneration in 1-mm polytetrafluoroethylene (PTFE) prostheses. Scanning electron microscopy was used to follow the progression of platelet deposition, fibrin layering, and endothelial cell migration along the graft. The endothelial healing process was divided into six stages: platelet aggregation (stage I); fibrin network (stage II); bridging (stage III); progression (stage IVA); transmural migration (stage IVB); intimal closure (stage V); and endothelial thromboresistance (stage VI).

Animals↗
PubMed1996

Biomechanical explanation of a simultaneous closed rupture of both flexor tendons in the same digit.

Closed ruptures of both normal flexor tendons in the same finger are extremely rare, only nine cases having been reported in the literature. The authors describe the case of a patient who sustained a closed rupture of both flexor digitorum profundus and flexor digitorum superficialis of the ring finger, following a forced hyperextension injury. The present paper highlights the importance of the mechanism of injury and explains biomechanical basis. The patient was treated by a two-stage reconstruction of the flexor digitorum profundus and regained full flexion and extension of the finger.

Adult↗
PubMed1995

Neo-endothelialisation of PTFE microvascular grafts: a five-year experience.

This paper presents the results of a 5-year experience of the implantation of 1 mm diameter polytetrafluoroethylene (PTFE) prosthesis in rodents. By evaluating the implanted grafts at different intervals, the process of neo-endothelial healing can be divided into six phases: Platelet Aggregation Phase (Stage I); Fibrin Network Phase (Stage II); Bridging Phase (Stage III); Progression Phase (Stage IV-A); Transmural Migration Phase (Stage IV-B) (only in optimal grafts, with thin wall and long fibril length); Intimal Closure Phase (Stage V); and Endothelial Thromboresistance Phase (Stage VI). Grafts with 60 or 90 microns fibril length offer enough "anchoring space" for the ingrowth of neo-endothelium and they act as a framework for the neo-endothelial invasion. Furthermore, this type of material allows intramural migration and penetration of cellular elements. In particular, a network of capillaries traversing the graft wall and opening eventually on the luminal surface can provide multiple sources of neo-endothelium, contributing to the development of the inner neo-endothelial lining. Scanning electron microscopy can favourably assist in the evaluation of different types of PTFE grafts, with regard to their fibril length, diameter, and wall thickness.

Blood Vessel Prosthesis↗