Endoscopic Treatment of Allergic Fungal Maxillary Sinusitis

Surgical removal of a Chalazion from the eye lid

A video showing Cystocele Repair

A dermatologist explains how this skin condition is recognised and treated and the challenging effects it can have on an individual.

The complex circuitry interconnecting different areas in the brain, known collectively as white matter, is composed of millions of axons organized into fascicles and bundles. Upon macroscopic examination of sections of the brain, it is difficult to discern the orientation of the fibers. The same is true for conventional imaging modalities. However, recent advancements in magnetic resonance imaging (MRI) make such task possible in a live subject. By sensitizing an otherwise typical MRI sequence to the diffusion of water molecules it is possible to measure their diffusion coefficient in a given direction1. Normally, the axonal membrane and myelin sheaths pose barriers to the movement of water molecules and, thus, they diffuse preferentially along the axon2. Therefore, the direction of white matter bundles can be elucidated by determining the principal diffusivity of water. The three-dimensional representation of the diffusion coefficient can be given by a tensor and its mathematical decomposition provides the direction of the tracts3; this MRI technique is known as diffusion tensor imaging (DTI). By connecting the information acquired with DTI, three-dimensional depictions of white matter fascicles are obtained4. The virtual dissection of white matter bundles is rapidly becoming a valuable tool in clinical research.

Our journey begins with a transverse section of tightly packed axons as seen through light microscopy. Although represented as a two-dimensional "slice", we see that these axons in fact resemble tubes. A simulation of water molecules diffusing randomly inside the axons demonstrates how the membranes and myelin hinder their movement across them and shows the preferred diffusion direction --along the axons. The tracts depicted through DTI slowly blend in and we ride along with them. As we zoom out even more, we realize that it is a portion of the corpus callosum connecting the two sides of the brain we were traveling on and the great difference in relative scale of the individual axons becomes evident. The surface of the brain is then shown, as well as the rest of the white matter bundles--a big, apparently chaotic tangle of wires. Finally, the skin covers the brain.

With the exception of the simulated water molecules, all the data presented in the animation is obtained through microscopy and MRI. Computer algorithms for the extraction of the cerebral structures and a custom-built graphics engine make our journey through the brain's anatomy possible in a living person.

Micrograph courtesy of Dr. Christian Beaulieu, University of Alberta.
Music by Mario Mattioli.

References:
1. Stejskal, E.O., et al., J. Chem. Phys., 1965. 42:
2. Beaulieu, C., NMR Biomed., 2002. 15:435-55.
3. Basser, P.J., et al., J. Magn. Reson. B, 1994. 103:247-54.
4. Mori, S., et al., NMR Biomed., 2002. 15:468-80.

Examination of the knee from Loyola medical school, Chicago

Deep Tie

Laparoscopic repair of hernia with mesh

Busadagur í fss 2008

Laparoscopic Sleeve Gastrectomy Operation

Surgical technique: A 3cm skin incision under spinal or general anesthesia, depending on the patients’ preference, starts half way the line between the superior anterior iliac spine towards the midline in a 30° angle to the pubic tubercle. Scarpa’s fascia is opened as well as the external obliq...ue aponeurosis. By using this skin line incision the internal ring will be immediately visualized. Although it is important to look for both direct and indirect hernias evaluating the groin, we do not taper the cord and directly evaluate the ring for indirect hernias. In case of an indirect hernia the sac is reduced or resected according to the preference of the surgeon and the preperitoneal space is entered bluntly through the dilated internal ring. In case of a direct hernia the approach slightly differs. One could prefer to open the transversalis fascia through the internal ring over a few centimeters or you can open the fascia more medially, at the site of the direct hernia. As primary point of concern the epigastric vessels should be identified and retracted softly upwards. Then a gauze can be introduced into the preperitoneal space and by doing so most of the space needed medially will be created. Then one can already palpate Cooper’s ligament and the pubic bone. Laterally to the internal ring more digital dissection is needed to create just the appropriate space for the mesh. By placing the mesh it is important not to introduce the mesh too medially. Laterally of the internal ring an adequate overlap of the mesh is necessary, especially in indirect hernias. No splitting of the mesh seems necessary. The patient will be asked to strain and push on the ring to control its place and to check adequate spreading of the mesh to cover the whole myopectineum of Fruchaud. One single stitch of vicryl 3/0 is placed taking both the fascia transversalis and the mesh.

Total laparoscopic hysterectomy using staples to secure major blood vessels. Vaginal colpotomy and mobilization of bladder performed initally with suture line at junction of vagina and cervix visualized laparoscopically.

This task requires cutting a circle from a rubber glove streched over 16 nails in a wooden board. Penalties are calculated when the cutting deviated from the drawn line. Score = time (seconds) + surface of glove in mgs deviated from circle. Performance standard: Score = 189 sec

Robotic Prostatectomy: Cornell Athermal Robotic Technique

Rhumatic fever has almost been eraicated in the developed world, however it remains prevelent in many under developed countries and causes devastating damage to heart valves. Up till recently valve replacement was the treatment of choice. The long term results and sequelae of valve replacement are...

common knowledge. Mitral and tricuspid valve replacement results are on the whole far worse than for example Aortic valve. Mitral valve replacement should be the last resort and patients with very severe valvular and sub valvular mitral disease can nowadays be helped by mitral valve repair. NO MITRAL OR TRICUSPID VALVE SHOULD BE REPLACED IF IT CAN BE REPAIRED

Modern technique of thyroidectomy for tumors

A LASAG Yag laser is in thermal mode, 1.5 Joules/pulse to treat the trabecular meshwork between the cornea and iris for glaucoma. The view is of the inside anterior eyeball.

Intussuseption and Appendectomy

Endoscopic finding in a patient with a typical rectal cancer (adenocarcinoma)

Most corneal transplants performed in the U.S. involve replacing the entire thickness of the diseased cornea with a healthy donor cornea (called penetrating keratoplasty or PK). In partial-thickness corneal transplants (LK), only the anterior (surface) layers of the cornea are removed. The donor cornea is then attached to the host corneal bed, containing only posterior (deeper) layers. LK is less risky, but tends to result in somewhat inferior vision vs. PK and cannot be performed if the disease process (e.g. scar) involves the deeper layers of the cornea.