Endoscopic ultrasound (EUS)

Today, three videos I’ve made of diagnosis and treatment of esophageal cancer were published on www.oncolex.no.

The voice overs are in Norwegian, but reading this post before watching the videos should make them understandable to non-Norwegians as well.

Endoscopic ultrasound (EUS)
This is a diagnostic procedure used, amongst other things, to screen for esophageal cancer. A special gastroscope, containing both a camera and an ultrasound probe is inserted into the esophagus. The gastroenterologist uses the camera to place the ultrasound probe in the desired location and then visualizes the surrounding tissues using ultrasound.

The purpose of the specific procedure in my video is to biopsy some abnormal lymph nodes using fine needle aspiration. With the probe in the right place and the lymph nodes visual on the screen, the doctor inserts a special biopsy needle into a canal in the gastroscope. The needle is then brought into the nodes and moved back and forth to gather cells. The aspirate is stained and viewed in a microscope immediately after the procedure.

Transhiatal esophagectomy (THE)
This is a video of a surgical resection of the distal part of the esophagus and the cardia, using the transhiatial approach. The top of the stomach is mobilized and the esophagus is dissected from the abdomen through the hiatus and mediastinum without opening the thorax. When this is done, the abdominal aorta and pleurae is visible in the video.

The stomach is modified to replace the resected part of the esophagus

The stomach is modified to replace the resected part of the esophagus. The stomach is cut below the cardia, and the greater curvature of the stomach is made into a tube using a surgical stapler.

The surgeon then moves to the neck. Making an incision on the left side he dissects down to the esophagus. It is dissected and cut. A ribbon is tied to the part that isresected. When the distal esophagus is pulled down into the abdomen, this ribbon is used to pull the tube shaped stomach up into the neck. The stomach and esophagus is joined by anastomosis, and a a stomach probe is placed in the stomach.

Esophageal stenting
For patients with inoperable esophageal cancer, stenting is an important treatment to make it possible for them to eat. If the esophagus is blocked (due to stenosis) a self-expanding stent can be placed in the esopaghus to ensure an open passage from the mouth to the stomach.

A gastrocope is used to guide the placing of the stent.

The stent is placed using a gastroscope. The esophagus and stomach is first examined visually. The upper and lower parts of the tumor are marked with small led balls using live x-ray. A guidewire is the placed in the esophagus and the stent is placed over this and put in the right location using live x-ray. Finally the placing is examined visually using the gastroscope.

The app is made by John Skidgel, and you can download it for free from his website. Read this post on how to use it. It’s an AIR app, so you’ll need to download Adobe AIR (also free) to make it work.

The last three years I’ve been working on a large project to document cancer diagnostics and treatment. With only one year left of the project I wanted to make a list of all the procedures I’ve filmed so far.

Probably not interesting to anyone but myself, but it’s my blog and I’ll list if I want to.

I’m currently working on sarcomas, skin cancer and melanoma, so those lists are still short. I’m starting on tumors of the liver, pancreas and other endocrine organs later this year. I have filmed a laparoscopic adrenalectomy, though.

Listed alphabetically by body location/system.

Breast cancer

• Axillary lymph node dissection
• Expander implants
• Lumpectomy
• Mastectomy
• Mastopexy
• Pleural effusion aspiration
• Prophylactic bilateral mastectomy
• Sentinel node biopsy
• Silicone implants
• Stereotactic core needle biopsy
• Ultrasound guided core needle biopsy
• Ultrasound guided FNA biopsy
• Wire localization

CNS tumors

• Awake craniotomy
• Craniotomy
• Craniotomy with neuranavigation
• Midfacial degloving
• Resection of spinal tumor
• Stereotactic biopsy
• Transphenoidal resection of pituitary gland tumor

Endocrine tumors

• Adrenalectomy (laparoscopic)

Gastrointestinal tumors

• Abdominoperineal resection
• Esophageal resection
• Hemicolectomy
• Hyperthermic intraperitoneal chemotherapy (HIPEC)
• Lower anterior resection with total mesorectal excision
• Peritonectomy
• Preoperative stoma placement
• Total gastrectomy

Gynecologic tumors

• Cervical conization
• Hysterectomy and bilateral salpingo-oophorectomy (open and robot assisted laparoscopic)
• Omentectomy (open and robot assisted laparoscopic)
• Radical hysterectomy (open and robot assisted laparoscopic)
• Paraortic lymph node dissection (robot assisted laparoscopic)
• Pelvic exenteration
• Pelvic lymph node dissection (open and robot assisted laparoscopic)
• Vulvectomy

Head and neck tumors

• Hemiglossectomy
• Laryngectomy
• Laryngopharyngectomy with jejunum graft reconstruction
• Mandibulectomy with fibular graft reconstruction
• Neck lymph node dissection
• Parotidectomy
• Partial horisontal mandibular resection
• Total thyroidectomy
• Ultrasound guided needle core thyroid biopsy
• Voice prosthesis placement

Leukemia and lymphoma

• Bone marrow aspiration and biopsy
• Lumbar puncture
• Neck lymph node FNA biopsy

Lung cancer

• CT guided FNA biopsy
• Endoscopic ultrasound (EUS)
• Endobronchial ultrasound (EBUS)
• Lobectomy

Sarcoma

• Extirpation of liposarcoma of the vastus medialis femoris
• Extirpation of synovial sarcoma of the elbow
• Radical hysterectomy for uterine sarcoma

Skin cancer and melanoma

• Inguinal lymph node dissection
• Photodynamic therapy (PDT)

Urologic tumors

• Bilateral orchiectomy (prostate cancer)
• Cystectomy with Bricker-type urinary diversion
• Cystectomy with Studer’s ileal neobladder
• Cystoscopy with PDD
• Nephroureterectomy (Wilm’s tumor)
• Orchiectomy (testicular cancer)
• Partial nephrectomy (laparoscopic)
• Partial penectomy
• Pelvic lymph node dissection (laparoscopic)
• Radical prostatectomy (open and robot assisted laparoscopic)
• Retroperitoneal lymph node dissection
• Sentinel node biopsy
• Transurethral resection of the prostate (TURP)
• Transurethral resection of the bladder (TURB)

A while back I wrote this post about the problems video cameras have with reproducing the insides of our bodies. The blood running through our bodies cause most tissues to be some shade of red.

This week I got an excellent opportunity to visualize this. I am currently filming a lot of operations for sarcomas of the upper and lower extremities. Depending on the situation of the tumor and other factors, the surgeons sometimes prefer to empty the blood from the surgical site before operating. An arm or leg can typically stay bloodless for about 2 hours before opening the tourniquet and letting the blood back in.

This technique allows the surgeons to work faster and more precisely as the separations of the different tissues and anatomical structures becomes more visible. The same applies to the camera. Without blood the highly saturated reds are gone, and you get colors that are easier to reproduce.

The video stills in this post are both from the same operation, an excision of a synovial sarcoma of the elbow. MRI indicated that the tumor infiltrated both major blood vessels and the median nerve. If this was the case, the arm could have to be amputated above the elbow. But the surgeons wanted to try to the excise the tumor first. Luckily there was hardly any infiltration at all and they were able to remove the tumor without damaging the surrounding structures.

The still above was taken just after the removal of the tumor. The median nerve can be seen going behind the scissors. The arm is still empty of blood at this stage and the blood vessels, nerves, muscles and fat are easily separated.

The still below was taken a few minutes after opening of the tourniquet. As you can see, all tissues now have a reddish color, making it harder to distinguish between them.

And yet, surgeons don’t perform open operations shrouded in darkness, do they?

The OR is of course also fully lit. To the people present in the room, the operating field will only seem slightly brighter than the rest of the room. The darkness visible on the video is due to the video camera’s relatively low contrast range compared to the human eye. This post is going to be a bit technical, but hopefully understandable (even for surgeons ;) ).

Where our eyes can handle a contrast range of between 1000:1 and 2000:1, the best professional video cameras can handle at the most 128:1 (7 stops). Smaller cameras like the Panasonic AG-HVX200 and the Sony HVR-Z1 can only handle a range of 64:1 (6 stops).

Decent exposure
Standard office lighting can range from 400 to 1000 lux. A surgical light however, can have a luminous emittance of up to 100,000 lux. In an OR the contrast between the brightest part illuminated by the surgical light and the brightest parts of the rest of the room will be about 100:1. This alone is more than most cameras can handle. Taking into consideration the less brightly lit areas of the room, the total range can be over 2000:1. Our eyes can handle this, but not the camera.

When a scene’s lighting contrast exceeds the camera’s range, detail and tonal gradation will be lost. The lightest areas will appear as solid white and the darkest areas will appear as solid black (see figure). Adjusting the exposure will not widen the camera’s range, only move it up or down the scale.

The surgical wound is the subject of the surgical video. The exposure will consequently have to be adjusted so the tones of the surgical field are reproduced correctly. By doing this most of the area outside the surgical light beam will appear as very dark or black, as in the video still above.

You get, to misquote Bruce Springsteen, “darkness on the edge of wound”.

Neutral density
Most lenses provide the best picture quality around the middle of the aperture range, typically f/4 to f/5.6. Working in a television studio or other locations where you can control the light, it is desirable to first set the aperture to e.g. f/4 and adjust the lighting to fit this. In the OR this is not possible, so other measures has to be taken to avoid working in the largest or smallest apertures.

To do this we use neutral density (ND) filters. These are filters which reduce the light of all wavelengths equally, providing lower exposure without altering the colors. ND-filters come in different densities. A ND8-filter reduces the aperture by 3 stops. Using this you can reduce your working f-stop from f/11 to f/4, allowing you more room to adjust the exposure and provide the best picture quality.

A blessing and a curse
When shooting the surgical field or parts of it, the surrounding darkness helps to guide the eyes of the viewers and exclude unimportant picture information.

When shooting wider pictures of the OR, e.g. cutaway pictures of the surgeons at work, it can be problematic. These pictures must be exposed to reproduce properly the part of the room which is not illuminated by the surgical light. To avoid clipping, the much brighter surgical field must be left off-screen, restricting the freedom of composition.

So these exposure challenges are both negative and positive. It’s important to know them to get the best possible footage from the OR.