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Biomedical subjects

J A Bertelli

Publications and source records attributed to J A Bertelli.

At least 37 records · Page 2Linked to original sources
PubMed1996

Is axonal sprouting able to traverse the conjunctival layers of the peripheral nerve? A behavioral, motor, and sensory study of end-to-side nerve anastomosis.

The repair of large peripheral nerve defects is not always possible, especially when the proximal stump is not available. In these cases, end-to-side nerve anastomosis has been proposed. In the present experiment, using the terminal branches of the rat brachial plexus, the authors studied behavioral responses after end-to-side nerve anastomoses using fibrin glue, 3 and 6 months after surgery. Rats were evaluated by results of a grasping test, a capsaicin test and a hot-plate test. The collected data demonstrated that there was no functional motor or sensory reinnervation after the end-to-side nerve anastomoses. The conjunctive layers of the peripheral nerve thus represented an effective barrier to reinnervation.

Anastomosis, Surgical↗
PubMed1995

The rat brachial plexus and its terminal branches: an experimental model for the study of peripheral nerve regeneration.

Despite the introduction of microsurgical techniques into clinical practice, the results of surgical procedures involving the brachial plexus and peripheral nerves are still far from spectacular. We therefore studied the rat brachial plexus and its terminal branches in 203 rats. Detailed anatomic and morphologic analyses of the biceps brachii and musculocutaneous nerve, finger flexors, flexor carpi radialis, and the median nerve were performed. Various sources of conventional and vascularized nerve grafts were explored. After musculocutaneous nerve section or median nerve section, there were no articular contractures or automutilations, which constitutes an advantage for these experimental models over the sciatic nerve model. The brachial plexus and its terminal branches provide a good experimental model which can be used to assess the development and normal control of muscle function, examine the mechanisms underlying functional recovery, and test the effects of treatments to enhance recovery.

Animals↗
PubMed1995

The grasping test: a simple behavioral method for objective quantitative assessment of peripheral nerve regeneration in the rat.

Behavioral recovery is the major goal of neuroscience research on the peripheral nervous system. However, behavioral methods of assessing peripheral nerve regeneration are still lacking. In the present work we used the median nerve and finger flexors as the experimental model. After resection or crush injury of the median nerve, rats were submitted daily to the grasping test. For this, they were gently lifted by the tail and allowed to grasp a grid connected to an ordinary electronic balance. While grasping the animal continued to be lifted by the tail with increasing firmness until it lost its grip. At this precise moment the value shown by the balance was recorded. In the crushed median nerve, recovery of function was clearly demonstrated by the grasping test. The test also indicated the exact day on which recovery began and its improvement with time. This very simple objective behavioral method provides a sensitive quantitative technique for assessing recovery. The experimental model using the median nerve seems to be better than the sciatic nerve model, as no articular contractures or autotomies were noted in the present experimental animals.

Animals↗
PubMed1995

Retrograde-flow neurocutaneous island flaps in the forearm: anatomic basis and clinical results.

The neurocutaneous island flap is an axial flap whose arterial vascularization is provided by the vascular plexus around and inside the cutaneous nerve. In previous studies we successfully harvested neurocutaneous island flaps in the hand and in the forearm. Here we report on reverse-flow neurocutaneous island flaps for reconstructions in the distal third of the forearm. The vascularization of the cutaneous nerve of the forearm was studied in 15 fresh human upper limbs injected with polyester resin. The vascularization of the cutaneous nerve was found to be very closely connected with the vascularization of the skin. A vascular arcade followed the cutaneous nerve of the forearm. These paraneural vessels linked the neurocutaneous perforators and together with the cutaneous nerve overlay a major vascular axis. A close relationship between the cutaneous nerve and the neurocutaneous perforators was clearly identified. The cutaneous nerve crossed in every instance the point at which the neurocutaneous perforators reached the skin. Anastomosis between the paraneural vessels and the intraneural circulation was consistently found. On the basis of these anatomic findings, reverse-flow neurocutaneous island flaps were raised on the forearm of three patients and are reported on.

Adult↗
PubMed1994

Median nerve neurotization by peripheral nerve grafts directly implanted into the spinal cord: anatomical, behavioural and electrophysiological evidences of sensorimotor recovery.

Over the years, peripheral nerve grafts, a favorable environment to support axonal elongation, have given rise to increasing interest as a possible solution for promoting spinal cord repair. In the experiments described here, following an avulsion injury of the rat brachial plexus, the median nerve was repaired by a peripheral nerve graft (PN) inserted directly into the dorsal side of the spinal cord. Eight months later the animals were submitted to behavioral tests, electrophysiological and histological studies. Regrowth of axons from both motoneurons and ganglionic neurons was demonstrated following a single superficial dorsal implantation of a PN. Sensorimotor peripheral reinnervation allowed most of the studied animals to recover enough flexor activity for grasping. Reinnervation was achieved even without prior root avulsion suggesting that the presence of a PN is sufficient to induce sprouting in the spinal cord from axotomized and non-axotomized neurons.

Animals↗
PubMed1994

Direct and reversed flow proximal phalangeal island flaps.

The vascularization of the skin over the proximal phalanx was studied in 64 digital microdissections from eight fresh upper limbs injected via the brachial artery with latex neoprene. Two branches of the proper digital artery reached the dorsal aspect of the proximal phalanx to supply the skin. The proximal branch diameter was 0.2 mm in average, and the distal branch diameter was 0.4 mm in average. A vascular arcade overlying the extensor tendon border linked these branches. Based on the anatomic findings, two cutaneous axial island flaps are presented: the direct and reversal flow proximal phalangeal island flaps. Five direct proximal phalangeal island flaps were harvested from the hands of five patients. The clinical results were satisfactory; all the flaps survived well. These flaps are useful to repair skin losses over the proximal and middle phalanges.

Child↗
PubMed1994

The inframammary island flap: anatomical basis.

The contribution of the thoracic internal artery to the breast's blood supply was studied in 24 fresh breasts. The second perforating artery was the largest in 20 breasts (86.3%). This artery supplies the upper portion of the breast, the nipple-areolar complex, and the subjacent anteromedial region. On the basis of these anatomical findings, we propose a new cutaneous island flap raised from the redundant skin that is normally discarded in reduction mammoplasty. The use of this flap is indicated in breast and thoracic wall reconstruction. A clinical case of such reconstruction is reported.

Adult↗
PubMed1994

Vascular freezing--a new method for immediate and permanent vasospasm relief: an experimental study in the rat.

Although much work has been done on the etiology and prevention of vasospasm, a spasmolytic agent capable of firmly protecting against or reversing vasospasm has not yet been found. In this paper, we describe a new physical method of treating vasospasm. It consists of directly freezing the arterial walls. Experiments were performed on the epigastric artery of 40 female Sprague-Dawley rats. A vasospasm was created by mechanical vessel manipulation. The vasospasm was treated by freezing the vessel walls with a dermatologic hand-held liquid nitrogen spray. Vascular spasm and patency controls were made immediately after thawing and 30 minutes and 3, 10, and 120 days after freezing. Epigastric island flaps were harvested based on the frozen artery at 3, 10, and 120 days after the freezing procedure. Histologic studies also were effectuated 3, 10, and 120 days after the freezing procedure. Relief from vasospasm was instantaneous and permanent. After freezing, almost all the cells in the media and endothelium died and the adrenergic fibers degenerated. This was followed by a phagocytic debridement, complete regeneration of the endothelium, and a limited regeneration of the muscle fibers in the media. The adrenergic innervation was recovered, and no alterations in the adrenergic fibers distal to the lesion were noted at any time. None of the arteries examined underwent thrombosis, and all the flaps harvested survived very well, indicating that the vascular bed distal to the site of the freezing was normal. This vascular freezing technique may well have clinical applications for microsurgical transfers and for the prophylactic treatment of vasospasm disease. However, its indications still require clarification.

Animals↗
PubMed1994

Brachial plexus repair by peripheral nerve grafts directly into the spinal cord in rats. Behavioral and anatomical evidence of functional recovery.

Over the years, peripheral nerve grafts, a favorable environment for the support of axonal elongation, have attracted interest as a possible means of promoting spinal cord repair. In the experiments described here, rats underwent an avulsion injury of the brachial plexus, and the musculocutaneous nerve was repaired by direct insertion of peripheral nerve grafts into the spinal cord. After varying postoperative periods, the rats were submitted to a series of behavioral tests to evaluate forelimb and hindlimb function. They also underwent retrograde double-labeling studies. Nerve grafts were harvested and processed for electronic microscopy. The biceps muscle was removed and weighed and its histology studied. After surgery, central axons effectively regenerated about 65 mm along the peripheral nerve grafts, restoring normal active elbow flexion. Forelimb movements were well coordinated in both voluntary and automatic activities. Clinical investigations showed that there were no side effects in the ipsilateral forepaw, contralateral forelimb, or either hindlimb. Regenerating axons stemmed from original motoneurons, foreign motoneurons, and even antagonist motoneurons, but this did not impair function. Ganglionic neurons from adjacent roots also sent processes to the peripheral nerve grafts.

Animals↗
PubMed1993

Nerve repair using freezing and fibrin glue: immediate histologic improvement of axonal coaptation.

Despite the fine microsurgical techniques available, injuries to peripheral nerves are still a surgical problem. Sutures placed in the epineurium or perineurium cause compression, brushing, and misdirection of endoneural tissue. A technique of nerve repair using freezing to trim the nerve and fibrin glue to coat it before thawing is described. The entire surgical repair procedure is carried out with the nerve stumps frozen. The observed axonal alignment with this technique was much better than that obtained by microsuture alone.

Anastomosis, Surgical↗
PubMed1993

Neurocutaneous axial island flaps in the forearm: anatomical, experimental and preliminary clinical results.

The neurocutaneous island flap is an axial flap composed of one vein and one nerve, the arterial vascularisation of which is provided by the vascular plexus around and inside the nerve. The vascularisation of the lateral and medial cutaneous nerve of the forearm was studied in twenty fresh human upper limbs. In ten rats the vascularisation of these nerves was studied using latex injection and in twenty other animals neurocutaneous island flaps were raised based on the lateral forelimb cutaneous nerve and the medial cutaneous nerves of the forelimb. There was always a consistent arterial longitudinal plexus along the human and animal nerves, which linked the cutaneous perforating arteries. All the experimental flaps harvested survived well. On the basis of these anatomical and experimental findings neurocutaneous island flaps were raised on the forearms of three patients and are reported on.

Animals↗
PubMed1993

Behavioral evaluating methods in the objective clinical assessment of motor function after experimental brachial plexus reconstruction in the rat.

Unfortunately, the results of brachial plexus surgery have not fulfilled expectations. Although the components of the rat brachial plexus are similar to those of the human plexus, experimental work in this field is limited. No functional test to assess experimental brachial plexus reconstruction has so far been published. We worked out a method of evaluating brachial plexus impairment in rats in the laboratory. It consists of a simple test in which a bowl of water is projected over the animal's head, eliciting grooming movements of the forepaws towards the head. This test is therefore called the 'grooming test'. A system of scoring the animals' performance is suggested. Rats were also submitted to walking tracks analysis, but this was of limited value in assessing brachial plexus impairment.

Animals↗
PubMed1993

[Longitudinal excursion of the sciatic nerve: an experimental study in the adult rat].

Every nerve must have the capacity to adapt to different positions by passive movement relative to the surrounding tissue. This capacity is called longitudinal excursion (LE). The LE of the sciatic nerve has been studied in 40 Wistar rats. The LE was measured, the nerve was cut, sutured, a metallic body was put into the anastomotic site for later radiographic controls (at the 8th week) and then the anastomosis was protected with different kinds of tissue. After 16 weeks the sciatic nerve was exposed, the LE was measured again and the nerve was dissected out for light microscopy. The LE is produced by two mechanisms: 1) rectification of the undulating course of the nerve and 2) elasticity of the neural connective tissue sheaths. The paraneurim provides a gliding tissue. During flexion movements, it acts as an external support and keeps the nerve under a longitudinal compression force. The normal LE is the release of this compression. These properties enable the nerve to glide without changing its diameter. The gag after nerve section is approximately 75% of LE. After repairing the nerve the new LE is 55% of the original value. In peripheral nerve surgery, to create a new nerve-bed or to protect the anastomoses, a muscle flap should be avoided. On the other hand, no difference could be found between other tissue flaps. When transposing a nerve, the submuscular position is preferable to the intramuscular position.

Adipose Tissue↗