Methylene blue soldered microvascular anastomoses in vivo.

OBJECTIVES: solders containing chromophores and proteins enhance the strength of lasered anastomoses. Methylene blue (MB) solder anastomoses in vitro are strong but no in vivo work has been reported. We used an MB solder in vivo and studied the effects of two laser powers on patency and histological appearance. DESIGN, MATERIALS AND METHODS: two groups of 15 rabbits had unilateral end-to-end carotid anastomoses (1.5-2.0 mm) formed using three stay sutures and MB solder. Group 1 anastomoses were formed at 5.7 Wcm(-1) and Group 2 at 2.8 Wcm(-1). The vessels were examined at various points by necropsy for patency and gross macroscopic appearance, with subsequent histological examination. RESULTS: group 2 showed patency of 93.3% v 0% ( p<0.001) endothelialisation of 100% v 26.6% ( p<0.001), giant cell formation 0% v 40.0% ( p<0.01), but stenosis was not significantly different (0% v 13.3% p=0.06). Group 2 showed a higher rate of intimal hyperplasia (IH) (66.6% v 20.0% p<0.05) but neither group exhibited thermal injury or aneurysm formation. CONCLUSIONS: laser soldered microvascular anastomoses were formed in vessels of 1.5-2.0 mm with a high degree of patency. A relationship appears to exist between laser power and anastomotic patency. Methylene blue fading has the potential to act as a switch against over exposure and a visual indicator of solder activation.

Methylene blue based protein solder for vascular anastomoses: an in vitro burst pressure study.

BACKGROUND AND OBJECTIVE: Attempts at sutureless anastomoses have used protein-based solders containing chromophores [Oz et al., J Vasc Surg 1990;11:718; Poppas et al., J Urol 1998150:1052] to enhance the strength of laser anastomoses. Reports have described the use of indocyanine green [Oz et al., Surg Forum 1989;316.], fuschin, and fluorescein isothiocyanate as chromophores [Chuck et al. , Lasers Surg Med 1989;9:471; Vance et al., Lasers Med Sci 1988;3:219]. Methylene blue (MB) is a chromophore with absorption peaks in the 600-700 nm region whose use has not been reported in laser-assisted vascular anastomoses. Therefore, we set out to produce and characterise a MB-containing protein solder. The absorption and burst pressure characteristics have been investigated and described as well as a brief review of the chemical and biological properties of MB. STUDY DESIGN/MATERIALS AND METHODS: The MB and porcine serum albumin (PSA)-based solder was produced and used to form end-to-end anastomoses in porcine splenic arteries. The solder was activated using a laser diode emitting at 670 nm. The burst pressures of the anastomoses were tested, and the results analysed as a function of MB concentration and absorption. In addition, the relationship between MB concentration and absorption was examined. RESULTS: A dose-response relationship was found between the measured absorption of the solder and the burst pressure of the anastomoses formed. Burst pressures exceeding physiological levels were found. Changes in MB concentration revealed a marked negative deviation from Beer's law at 670 nm, owing to the monomer-dimer-trimer equilibria. CONCLUSION: PSA with MB solder is able to form high-quality end-to-end anastomoses, with immediate burst pressure profiles similar to those previously described for sutured [Quigley et al., Microsurgery 1985;6:229], lasered [Quigley et al., Microsurgery 1985;6:229], and soldered anastomoses [Small et al., J Clin Laser Med Surg 1997;15:205]. The relationship between burst pressure strength and chromophore absorption is discussed.

Botulinum toxoid in the management of gustatory sweating (Frey's syndrome) after superficial parotidectomy.

Botulinum toxin has been successfully used to treat Frey's syndrome occurring in a 31-year-old patient following superficial parotidectomy for pleomorphic adenoma. An initial injection of 7.5 U (0.3 ml over 6 cm2 of cheek) resulted in 3 months' resolution of gustatory sweating and flushing and a second injection 12 months' symptomatic improvement. The symptoms recurred after further facial surgery.

A cost-benefit comparison of self-expanding metal stents and Atkinson tubes for the palliation of obstructing esophageal tumors.

This retrospective study was undertaken to assess the cost-benefit aspects of self expanding metal stents (SEMS), versus Atkinson Tubes (AT) in the palliation of obstructing esophageal tumors. Over a 4 year period, 50 patients received palliative endoscopic intubation for inoperable esophageal malignancy. Patients either received an AT or a newer, but more expensive, SEMS, both inserted under general anaesthetic. Both patients cohorts were assessed in terms of the severity of their dysphagia and scored according to Atkinson and Fergusons' classification both pre- and post-operatively. Other factors that were considered included length of hospital stay, number of interventions, admission to the Intensive Treatment Unit (ITU), and rates of post-operative complication. The majority of tumors were either adenocarcinoma or squamous cell carcinoma. The location of the tumors (upper, middle or lower) were similar in each group as was the mean length of tumor being 7 cms in SEMS and 5 cms in AT. There were significantly more complications in the AT group compared to the SEMS group (p < 0.05). The most common complications in the AT group were tube displacement (21%), tumor overgrowth (26%) and esophageal perforation (13%). In contrast complications of the SEMS group were tumor overgrowth (15%) and esophageal perforation (8%). Mean hospital stay was 3 (1-30) days for SEMS and 8 (2-122) days for AT (p < 0.05). The median total cost of hospital stay was 1745 pounds (1027-5424) for SEMS versus 2349 pounds (1163-24,481) for AT.