M.L. Manunta

Magnetic resonance imaging of the brain and skull of sheep with cerebral coenurosis

OBJECTIVE To determine MRI characteristics of the skulls and brains of sheep with chronic cerebral coenurosis (CC) caused by naturally acquired Taenia multiceps infection. ANIMALS 33 sheep with CC and 10 healthy control sheep. PROCEDURES Sheep underwent MRI of the head. Volumes of the cranial cavity and rostral and caudal fossas of the cranial cavity were determined. For CC-affected sheep, the number, location, and volume of T multiceps cysts were determined and the percentage volumes of cysts in the cranial cavity and rostral and caudal fossas of the cranial cavity were calculated. Focal and diffuse abnormalities of cranial bones in CC-affected sheep were identified. Brain edema and hemorrhage and signs of increased cranial pressure (ICP) in MRI images were determined. RESULTS Volumes of the cranial cavity and rostral and caudal fossas of the cranial cavity were significantly larger for CC-affected sheep versus healthy control sheep. Total volumes of cysts ranged from 4.40% to 46.93% in cranial cavities of sheep, 4.12% to 51.53% in rostral fossas of cranial cavities of sheep, and 15.24% to 68.30% in caudal fossas of cranial cavities of sheep. Moderate to severe diffuse cranial bone abnormalities and signs of increased ICP in MRI images were detected in 21 and 24 sheep, respectively, and were positively correlated with cyst volumes. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that cranial cavity volume and morphological abnormalities can be detected in sheep with CC. These changes may reflect abnormalities in ossification of the cranial bones secondary to chronically increased ICP caused by development of T multiceps cysts.

Subchondral bone remodeling: comparing nanofracture with microfracture. An ovine in vivo study.

PURPOSE microfracture, providing direct stimulation of chondrogenic mesenchymal stem cells (MSCs) in the subchondral bone, remains the most frequently used primary cartilage repair technique. However, the newly formed type I collagen-rich fibrocartilaginous tissue has poor biomechanical properties and a tendency to degenerate. To overcome these limitations the nanofracture technique was introduced. Our purpose was to compare subchondral bone remodeling 6 months after microfracture versus nanofracture (subchondral needling) treatment in an ovine model. METHODS full-thickness chondral lesions were created in the load-bearing area of the medial femoral condyles in four adult sheep. Each animal was then treated on one side with microfracture and on the contralateral side with nanofracture. Subchondral bone remodeling was assessed by micro-CT using a Bruker(®) SKYSCAN and CTVOX 2.7 software (Bruker Corp., Billerica, MA, USA) for image reconstruction; trabecular bone density measurements were performed through a color-representation structure thickness analysis. RESULTS at the six-month endpoint, the microfracture-treated samples showed limited perforation depth and cone-shaped channels with large diameters at the joint surface. The channel walls displayed a high degree of regularity with significant trabecular bone compaction leading to a sealing effect with limited communication with the surrounding trabecular canals. Condyles treated with nanofracture showed channels characterized by greater depth and smaller diameters and natural irregularities of the channel walls, absence of trabecular compaction around the perforation, remarkable communication with trabecular canals, and neo-trabecular remodeling inside the channels. CONCLUSIONS nanofracture is an effective and innovative repair technique allowing deeper perforation into subchondral bone with less trabecular fragmentation and compaction when compared to microfracture; it results in better restoration of the normal subchondral bone architecture at six months. CLINICAL RELEVANCE our data support the use of smaller-diameter and deeper subchondral bone perforation for MSC stimulation; this technique may prove to be an attractive alternative to standard microfracture procedures.

Lumbar interbody expanding cage. A preliminary study on an animal model.

Interbody fusion devices are used in human medicine for treating degenerative diseases of the spine. Currently, there is not a universally accepted assessment tool for determining fusion, and the definitive criteria for diagnosing a successful interbody fusion remain controversial. The aim of this study was to describe microscopic and helical computed tomography (CT) imaging in the assessment of lumbar interbody fusion using cylindrical threaded titanium expanding cage in sheep. One cylindrical threaded expanding titanium cage (Proconcept--SA, Orange, France) was inserted through a transperitoneal approach after radical discectomy and packed with cancellous bone autograft in five adult sheep. The subjects were euthanatized after three, six, 12, 18 and 24 months. CT images revealed lumbar fusion at 12 months post operation, whereas microscopic evaluations indicated the presence of lumbar fusion at 18 months. CT and histological grades were the same in 65% of the cases observed. There were not a significant difference between CT, histological and micro radiographic grades. Helical CT scanning can be considered to be a suitable method for the monitoring of lumbar fusion as it enables observation of the deposition of bony bridging within the cage.

The use of embryonic cells in the treatment of osteochondral defects of the knee: an ovine in vivo study.

PURPOSE the aim of this study was to determine whether local delivery of embryonic stem-like (ESL) cells into osteochondral defects in the femoral condyles of sheep would enhance regeneration of hyaline articular cartilage. METHODS male ESL cells embedded in fibrin glue were engrafted into osteochondral defects in the medial condyles (ESL-M) of the left femur in 22 ewes. An identical defect was created in the medial condyle of the contralateral stifle joint and left untreated as a control (empty defect, ED). The ewes were divided into 5 groups. Four sheep each were euthanized at 1, 2, 6, and 12 months from surgery, and 6 ewes were euthanized 24 months post-implantation. To study the effect of varying loads on the long-term regeneration process, an identical defect was also created and ESL cell engraftment performed in the lateral condyle (ESL-L) of the left stifle joint of the animals in the 12- and 24-month groups. The evaluation of regenerated tissue was performed by biomechanical, macroscopic, histological, immunohistochemical (collagen type II) and fluorescent in situ hybridization (FISH) assays. RESULTS no significant differences were found between treated and control sites in the biomechanical assays at any time point. ESL cell grafts showed significantly greater macroscopic evidence of regeneration as compared to controls at 24 months after surgery; significantly better histological evidence of repair in ESL-M samples versus controls was found throughout the considered period. At 24 months from surgery there was significantly improved integration of graft edges with the host tissue in the ESL-M as compared to the ESL-L samples, demonstrating that load bearing positively affects the long-term regeneration process. CONCLUSIONS ESL cells enhanced the regeneration of hyaline cartilage. FISH confirmed that the regenerative tissue originated from ESL cells. CLINICAL RELEVANCE ESL cells are able to self-renew for prolonged periods without differentiation and, most importantly, to differentiate into a large variety of tissues.

Cisternal cerebrospinal fluid analysis in 24 sheep with chronic coenurosis.

Coenurosis, a neurological parasitic infection of ruminants caused by the larval stage of Taenia multiceps, is commonly reported in Sardinia, the most representative region for ovine population in Italy. Chronic form appears as a consequence of cyst development, frequently reported in the brain and spinal cord. Diagnostic suspect of coenurosis is based on physical and neurological examination. The aim of this article is to describe physical, biochemical and cytological aspects of cisternal cerebrospinal fluid of 24 sheep with chronic coenurosis and to evaluate whether these alterations are helpful in the diagnosis of coenurosis. Cerebrospinal fluid was altered in 20 animals (83.3%). Increase of total protein was revealed in 7 animals (29.2%); an increase of total nucleated cell count was observed in 18 samples (75%). Cytological examination revealed mononuclear pleocytosis in 17 animals (70.1%). Eosinophils were observed in 16 animals in various degree (66.7%). Our results show that cerebrospinal fluid confirms signs of Central Nervous System inflammation in 20 animals out of 24 (83.3%) and in particular it was useful to identify a parasitic inflammation in 66.7% of the animals in which eosinophils were observed. Considering the results of this study, the very absence of significant neutrophilic pleocytosis could be considered useful to diagnose chronic cerebral coenurosis.

Clinical evolution of cerebral coenurosis from invasive to chronic infection in sheep and a goat

This survey describes the evolution in vivo of Coenurus cerebralis in small ruminants. At presentation, neurological signs and cerebrospinal fluid (CSF) features were suggestive of multifocal or diffuse inflammatory reaction. Magnetic resonance imaging (MRI) captured the transition between the invasive and quiescent phase of the infection, revealing the concurrent presence of meningitis and small cysts. During the quiescent phase, in all animals, neurological symptoms disappeared, and cerebrospinal fluid was unremarkable while cysts grew progressively. Subsequently, the onset of neurological symptoms coincided with MRI signs of diffuse or localized increase of intracranial pressure, as confirmed by direct intracranial pressure measuring. All the animals had an excellent post-surgical recovery. This is the first report describing the evolution of coenurosis in vivo. Sequential imaging allowed describing interesting such as the death of some coenuri and different parasite growth rate in the same host.

Substitution of thoracic oesophagus by interposition of a pedicled gastric tube, preserving LES function: clinical and histological follow-up

Assessment of clinical evolution and histological findings in a group of animals experimentally operated on to substitute the thoracic oesophagus with a gastric tube. Six piglets underwent oesophageal replacement with a gastric tube, constructed from the greater curvature of stomach and pedicled on the gastroepiploic vessels, which was interposed between the oesophageal stumps. At follow-up, all animals were found to be growing and eating normally, apart from case no 1 (stenosis of the lower oesophageal anastomosis). Ph-metry showed a neutral pH on the gastric tube. Postmortem histological analysis of the gastric tube and native oesophagus samples did not show any significant lesions, except in case no 1 (inflammation of the gastric tube and upper oesophagus due to food stasis). The technique of substitution of the oesophagus with an interposed pedicled gastric tube can be a breakthrough in existing surgical methods of oesophageal replacement.

Experimental use of labial mucosa free graft urinary conduit in the Mitrofanoff principle

PURPOSE One method of treating urinary incontinence is to create a catheterizable and continent vesicostomy by the Mitrofanoff principle, based on the use of a conduit, which in the original method is the appendix. The authors present an experimental technique in which a continent vesicostomy is created by the Mitrofanoff principle, using a conduit made of a labial mucosa free graft. METHODS Six 30-day-old pigs underwent surgery to create a continent vesicostomy by the Mitrofanoff principle. A tube, made of labial mucosa free graft from the lower lip, was used. The labial mucosal conduit was anastomosed to the bladder mucosa. The tunnel was then prepared, part of which passed through the fibers of the right rectus muscle. The conduit was taken through the tunnel and anastomosed to the skin in the right iliac fossa. RESULTS Fifty days after the operation, the vesicostomy was continent, pervious, and easily catheterizable in 5 animals. In the sixth pig, the cystostomic tube did not graft successfully because it was infected. CONCLUSIONS A number of investigators have extrapolated Mitrofanoff method using the ileum, the ureter, or others. The use of a tube made by labial mucosa free graft is an easily performed technique, and as with the Mitrofanoff method, continence and easy catheterization are successfully achieved.

Development of a Device-Assisted Nerve-Regeneration Procedure in Disruptive Lesions of the Brachial Plexus

Background We describe the development of a new surgical procedure to be used in the treatment of disruptive brachial plexus (BP) lesions. It is centered on an artificial device designed to assist nerve regeneration by providing a confined and protected environment. Nerve fibers can repair inside the device, while the adverse massive scar‐tissue formation is limited to the outside of the device. Methods Steps in the development of the procedure were (1) definition of the rationale, (2) design of the device, (3) choice of an in vivo translational model, (4)refinement of the surgical procedure, and (5) performance of an in vivo pilot study as a proof of concept. An interdisciplinary team from several laboratories was involved in this work over a period of 6 years. Results Results showed the absence of significant scar tissue in the regenerate and the presence of myelinated fibers aligned proximodistally between the stumps. This surgical approach can be seen not only as a definitive treatment but also as an early examination and stabilization before some different surgery will be later performed. It may also be used as additional protection for traditional surgery like end‐to‐end coaptation. Conclusions We conclude that the availability of a suitable device‐assisted early treatment, even if not to be considered definitive, could help in addressing the BP lesions at an earlier stage and this may improve the final outcome. Our evidence justifies further experimentation on this approach.

Magnetic resonance imaging features of progressive ethmoid hematoma in 2 horses.

Progressive ethmoid hematoma is frequently reported among the pathologies of the upper airways in horses. While several hypotheses have been proposed such as repeated trauma, inflammatory processes and/or chronic infections, congenital phenomena, complication of hemangiomas, and neoplastic processes, the aetiology of this condition is yet unknown. Clinical symptoms are non-specific and includes haemorrhagic nasal discharge, respiratory noise not related to physical exercise and, in most severe cases, phenomena of coughing. The purpose of this case report is to contribute to a correct diagnostic approach to this particular pathology of upper respiratory tract in horses. Magnetic Resonance allows for a very detailed imaging of the development of the disease and suggests appropriate therapeutic choices.