Microvascular anastomosis using loupes and smartphone magnification: Experimental study for application to limited-resource environments

Finger revascularization has been performed without a microscope in limited-resource environments only when absolutely necessary. This experimental study sought to assess the feasibility of microvascular anastomosis in rats performed using loupes or smartphone magnification. Thirty rats were divided into three groups of 10 individuals according to the magnification method used: operating microscope (control group M), surgical loupes (group L) and smartphone (group S). The infrarenal aorta was dissected under a microscope, then anastomosed by interrupted sutures using the group-specific magnifying device. The main analytical criteria were vessel diameter, anastomosis duration, immediate flow patency (T0), patency after one hour (T1) and anastomosis quality. Anastomosis duration was comparable between groups M and L, but was twice as long in group S. The number of leaks at clamp removal was higher in group S. Patency rates at T0 and T1 were 100% in groups M and L, but were significantly lower in group S. The anastomosis quality was low in group L and poor in group S. Anastomosis of digital arteries using loupes is possible, but the resulting quality is lower than with a microscope. Current smartphones are not adequate for performslt ing microvascular repairs in a living model.

Anastomose trachéale : fil monofilament résorbable versus non résorbable

OBJECTIVES

When tracheal stenosis is symptomatic, the treatment may consist of surgical resection and anastomosis. A multifilament absorbable suture is usually used. The aim of this experimental work on rats was to study the benefits of using a monofilament absorbable suture with high initial resistance.

MATERIAL AND METHODS

We compared Ethilon, a nylon monofilament non-absorbable suture (MNA), with Monocryl, a polyglecaprone 25 (P25) monofilament absorbable suture (MA). The sutures were used for tracheal anastomosis on 16 rats. P25 has a high initial strength but its intra-tissular disappearance is fast. Animals were killed at 1, 2 and 3 months. Anastomoses were studied by optical microscopy and histological analysis.

RESULTS

At 3 months no disunity or stenosis was seen with the MA. With the MNA, a modification of the tracheal transverse section and a stenosis were observed. The histological examination showed an initial important inflammatory cell reaction with the MA and at 3 months, a surgery-free like tracheal aspect. At 3 months the rats with MNA had a persistent foreign body cell reaction.

CONCLUSION

Good results obtained by using P25 could be due to high initial resistance of the suture protecting the anastomosis. The semi-fast absorption of the suture avoided persistent inflammatory cell reaction. Confirmation of these results by working on larger animals and tracheal anastomosis under tension could allow the use of this suture on human beings, in this instance.

[Vascular microsurgery and progress of free flap surgery]

In 1960 Jacobson and Suarez realized and described the first vascular microanastomosis. They introduced microsurgical operating technique, improved instrumentation and operating microscope. Many improvements were tried: vascular intubation, laser, biological glue, microvascular anastomotic system, non transfixing microstaples. After expert's report, these techniques have shown many drawbacks and have not supplanted the manual anastomosis. The failure rate was 6.6% in a review of 9,503 cases from the literature. The rate of vascular thrombosis decreased when subcutaneous heparin was administered in the post-operative period. Microvascular surgery has become an important method for reconstructing complex surgical defects by using free vascularized transplants. The majority of free flaps were applied to the reconstruction of defects resulting from tumor ablation or trauma. The recipient sites were mainly distributed to the head and neck and to the limbs. Reconstruction of an irradiated recipient site is a significant predictor of failure. The vascular microsurgery using thread and needle requires a strict training with an important invested time.

Protective effects of Celsior in lung transplantation

BACKGROUND

Celsior is a new preservation solution for heart transplants that recently has been shown also to improve protection of pulmonary grafts. As these data were obtained in isolated lung preparations, we sought to perform further tests with an in vivo model of allogeneic lung transplantation.

METHODS

The left lungs of 41 rats were either transplanted immediately after harvest (controls) or flushed with and cold stored in Celsior or the blood-based Wallwork solution for 5 or 12 hours. Lungs were then reperfused for 30 minutes, after which ligation of the contralateral pulmonary artery and bronchus made the recipient rat exclusively dependent on the transplanted lung. Assessment of preservation was made on functional (blood gases, pulmonary hemodynamics) and structural (dry-to-weight ratio, light microscopy, myeloperoxidase [MPO] content) end points.

RESULTS

The protective effects of Celsior were primarily manifest, once the contralateral lung had been functionally excluded, as a better preservation of oxygen tensions in the 5-hour storage experiments (416 +/- 52 mm Hg vs 406 +/- 59 mm Hg in controls [p = NS] and vs 239 +/- 34 mm Hg in Wallwork [p < 0.05 vs the 2 other groups]) and a smaller increase in pulmonary vascular resistance in the 12-hour storage experiments (10.2 +/- 4.1 mm Hg/mL/minute vs 3.2 +/- 1.1 mm Hg/mL/minute in controls [p = NS] and vs 23.1 +/- 4.3 mm Hg/mL/minute in Wallwork [p < 0.02 vs Celsior, p < 0.002 vs controls]). Survival was also longer in the 12-hour preserved Celsior group. Other end points were not significantly different between the two preservative solutions.

CONCLUSION

These data support the efficacy of Celsior as a flush-out and storage solution for pulmonary grafts. Given its previously documented ability to adequately preserve heart transplants, Celsior might provide a unified "solution" to thoracic organ preservation.

Effect of converting enzyme inhibition on allograft-induced arterial wall injury and response

Converting enzyme inhibition (CEI) can prevent myointimal proliferation after arterial wall balloon injury. Because intimal proliferation is the main long-term complication of chronic vascular rejection, we tested the effect of CEI (perindopril, 1 mg/kg twice a day) on arterial rejection-induced intimal proliferation, using a model of aortic allograft in normotensive Wistar-Kyoto and spontaneously hypertensive rats. Eight-week-old rats were grafted and studied 2 months later. The structural parameters of the transplanted aortic wall were measured by morphometric analysis of specifically stained, formol-fixed sections. CEI did not prevent adventitial inflammatory infiltration but significantly increased the number of living cells and prevented the partial destruction of elastic laminae in the media, thereby increasing medial thickness to close to that of sham-operated controls. CEI significantly decreased intimal thickness and intimal collagen density, without changing the absolute number of intimal smooth muscle cells. The intimal thickness and the intimal collagen density were significantly correlated with the effect of CEI on blood pressure. CEI partially prevented the consequences of immune injury to the media within the arterial wall, probably by suppressing the proinflammatory activity of angiotensin II. It also decreased the recipient arterial wall response by acting more on the trophicity of intimal cells and on their ability to produce collagen rather than by directly inhibiting smooth muscle cell proliferation in our model of arterial allograft.

Portable stimulator for direct electrical stimulation of denervated muscles in laboratory animals

A portable lightweight stimulator for small animals is described. It delivers pulse trains of high intensity and is convenient for denervated muscle studies. It does not cause discomfort and does not restrict activity.

Prostaglandin E2-induced changes in the distribution of glycosaminoglycans in the isolated rat uterine cervix

In order to study the hormonal control mechanisms of cervical ripening, we investigated the prostaglandin E2 (PGE2)-induced changes in the distribution of glycosaminoglycans (GAG) using hysterectomized and ovariectomized rats, leaving the vascularized uterine cervix in situ, as an animal model. In the first series of experiments, the GAG were measured in a control (n = 22 Wistar rats) and in a PGE2-treated group (n = 20 Wistar rats) without steroid supplementation. In the second series of experiments, the GAG were measured in a control (n = 19) and in a PGE2-treated group (n = 18) receiving estradiol and progesterone supplements. After PGE2 treatment in the two series of experiments, and despite being surgically isolated from the uterine corpus, the cervix was still able to undergo some of the structural changes associated with normal ripening (increased hydration and hyaluronic acid concentration). This suggests that PGE2, acting directly on the cervix, could be, at least in part, a modulator of biochemical events which underlie normal cervical maturation. The animal model described here seems to be suitable for studying the hormonal mechanisms of cervical ripening and the regulatory relationship between cervical maturation and myometrial contractility, which are probably subject to concordant endocrine regulation.