This electronic dissection is based on the surgical posterior approach to the kidney
|History and Physical and Labs
(Translation of shorthand is in italics)
CC: Blood in urine.
HPI: 56 year old woman came to the ED after she discovered blood in her urine this morning. She denies any prior urinary tract infections. Reports no pain on urination, nor increased frequency. No fever or chills. No recent weight loss, but reports she fatigues more easily. She reports no other health concerns and cannot recall when she was last examined by a physician.
PMH: no past medical or surgical history
FH: HL’s grandparents moved to the US from Sweden. Her paternal grandfather died of renal cancer.
SH: Married with two grown children. Lives with her husband. She smokes 2 packs of cigarettes/day.
Physical Exam: high blood pressure (hypertension), and gross hematuria.
WN (well nourished) WD (well developed) moderately obese female
VS: T=101 HR=72 RR=12 BP=160/92
Neck: No JVD, no lymphadenopathy, strong carotid pulses, no bruits
Lungs: CTA (clear to auscultation) bilaterally
Heart: RRR, S1/S2 normal, no murmurs, rubs, or gallops
Abdomen: Soft, nontender, nondistended, no flank tenderness, no masses, (+) left renal bruit, no hepatosplenomegaly
Extremities: warm, well-perfused
Neuro: A&Ox3, CNII=XII grossly intact. Reflexes normal and symmetric. Strength, sensation normal.
Notable for abnormal kidney function and mild anemia.
Which organ systems do the chief complaint and history of the present illness
lead you to consider?
Blood in the urine (hematuria) can result from kidney infections, cancer, or stones. It can also result from infections of the urinary bladder, especially in women (or prostate disease if HL were a man). (Some metabolic diseases can also cause blood in the urine.)
Which findings of the social history and family history are consistent with your answer to the previous question?
Renal cancer is suggested, because there is a genetic component to it. Her father's disease and Swedish heritage put her at greater risk. Her smoking also increases her risk.
Which findings of the history and physical and lab results support or contradict your impressions thus far?
Hypertension (the kidney regulates blood pressure; Left renal bruit - a tumor could partially occlude the artery); abnormal kidney lab tests; Although no mass is palpated, this is not uncommon for renal cancer, especially in early stages.
Why would stenosis of the renal artery result in systemic hypertension?
The stenosis would lower blood pressure within the kidney. The kidney would react to the low blood pressure by secreting a hormone (renin) that would increase systemic blood pressure.
Examine the CT reconstruction of the kidneys from a normal patient. Determine the relative length of the left and right renal arteries and veins. Now examine the CT of the patient for this case.
For an overview of kidney function, you might like to do this pyleogram webactivity. (Ignore the error messages and scroll down the page to begin the exercise.)
Click this link to set up your session. Some structures have already been highlighted: Kidney, purple; Skeleton, white; Aorta, red; Inferior Vena Cava (IVC), Blue. Please dissect the left and right sides (a bilateral nephrectomy!)
1. Review the musculature of the back by selecting the highlight tool (under the 3D window) and rolling your mouse over the various structures. Labels will appear at the top of the window.
2. Find the iliac crests and infer the position of L4 vertebral spine. Count vertebra to find T12. Zoom the image and re-center the image on this region.
When rolling over the inferred position of the L4 spine, the label "thoracolumbar fascia" appears, whereas "T12" appears when you roll over that spine. What is the anatomical explanation?
Find out by grabbing the image in the transverse window (click the move icon below the window to get the hand tool) and move the posterior vertebral spine into the cross hairs. Inspect the sagittal window. Notice the curvature of the vertebral column and how the thoracic vertebrae come close to the skin, but the lumbar vertebra are covered by muscle. Look at the coronal window. Notice how you see the thoracic spinal cord, but the erector spinae muscles in the lumbar region.
How then, would you do a lumbar puncture between L3 and L4?
The lumbar spines are more readily palpable by asking the patient to lay on the side in a fetal postion. This position flexes the vertebral column, and brings the spines closer to the skin. The main reason for flexing the column is to increase the distance between the laminar arches so that you can insert a needle into the vertebral canal.
Note: If your screen is small you can get a larger image by finding the “Views” button in the top-left corner. Select the 3D view from the pulldown menu. (You can always return the the full view towards when the instructions reference the sectional windows.)
3. Select the dissect tool under the 3D window. Dissect the latissimus dorsi and the thoracolumbar fascia (the aponeurosis of the latissimus dorsi).
What is the function of this muscle?
This extrinsic back muscle adducts and extends the arm.
4. Dissect the erector spinae muscles (iliocostalis, longissimus, and spinalis).
What is the function of these muscles?
These are intrinsic back muscles that can extend and laterally flex the vertebral column.
5. Identify and dissect the quadratus lumborum muscle, which is a body wall muscle that acts on the ilium, 12th rib and vertebral column.
What is the function of this muscle?
This bodywall muscle acts on the ilium, 12th rib and vertebral column. It stabilizes the 12th rib on deep breathing, elevates the hip, and can extend or laterally flex the vertebral column.
6. Scan with your mouse to identify retro-peritoneal fat and dissect it.
7. Identify rib 12 and highlight the subcostal nerve just inferior to it.
8. Go to the index tab and search "ilio". Note: To get back to the lesson, choose the lesson tab from this same row of tabs (not the uppermost row!). Select, add and highlight the iliohypogastric and ilioinguinal nerves. Trace these nerves medial until they fuse to form T12/L1. Although a fusion of a T12 branch and L1 can be observed, the iliohypogastric and ilioinguinal nerves are primarily L1 nerve fibers.
9. To appreciate the view in 3-D use the following method to rotate the image. Use the Ctrl or Command key together with the left or right arrow to slowly rotate the image back and forth in 5 degree increments.
10. Return to the posterior view. Dissect the psoas muscle.
What is the function of this muscle?
This bodywall muscle flexes the hip joint.
The kidney is surrounded by two layers of fat. The pararenal fat lies outside the renal fascia of Gerota, while the perirenal fat and the kidney lie within it. To minimize the risk of spreading the cancer, the surgeon would like to avoid cutting the renal fascia and remove the kidney, perirenal fat, and renal fascia as one unit.
11. Mouse around to identify and dissect the pararenal fat; now identify and dissect the perirenal fat. The purple structure that is revealed is the kidney.
12. Note that the left kidney is more superior than the right.
13. Rotate the image incrementally to appreciate the 3-dimensionality of the image.
14. Note how the kidney is partially protected by rib 12. Dissect Rib 12 and the intercostal muscles (and levatores costarum) superior to it.
15. Identify and dissect the remaining muscles that obscure the kidney. Of these, only the phrenic diaphragm is of clinical importance.
16. Identify and highlight the suprarenal (adrenal) glands.
17. To see structures related to the kidney hilum, open the systems tab. Open muscles, muscles of the back and select “muscles of the back proper” and click “dissect”. These muscles rotate, flex and extend the vertebrae.
18. On the left, work from superior to inferior to highlight the: renal artery, vein, pelvis, and renal accessory artery (an embryonic vestige that is seen on occasion).
19. Dissect vertebrae L1-L3. (The surgeon would not do this!)
20. To clarify this image, you will need to dissect the contents of the vertebral canal and various vertebral ligaments and veins. From the index, search "ligament". For ease, select them all and click remove. From the Systems Tab, open Nervous System/central nervous system, and select "Meninges" and Click remove. Select "Spinal cord" and click "add and highlight".
Identify the vertebral level of the spinal cord's most inferior extent by mousing down the midline. What did you find and what is this terminal region of the cord called?
L2; Conus medularis
Nerve rootlets obscure the spinal cord, making it hard to observe its most inferior extent.
What is the collective name for these rootlets below L2?
From the index, search nerve. Select and remove lumbar nerve L1-L5. Select and remove sacral nerve S1-5.
Now, dissect the spinal cord.
21. Dissect the intervertebral discs and basivertebral veins, lumbar veins, and lymph nodes that obscure your view of the aorta and IVC. Note the unusual left renal vein that travels posterior to the IVC.
22. Now you can identify the ureter, extending from the renal pelvis and traveling with the testicular artery and vein. Note that the artery stems from the aorta and the vein drains into the renal vein. To find all of these structures, you may have to rotate the image one or two clicks to the left or the right. .
23. Repeat steps 20-22 on the right. This would be a good time to rotate the image incrementally, back and forth to appreciate the structures in 3 dimensions
24. If you have been using the 3D view, find the “Views” button in the top-left corner and select the Full view from the pulldown menu.
25. In the 3D window, open an axial plane (outlined in blue), grab it with the mouse, and move it to the kidney (you may have to zoom out to find the plane). The lower left window will show you this plane.
26. Manipulate the sectional windows to explore and trace the structures that you highlighted in the posterior view of the 3D window. Take time to incrementally rotate the window. In the transverse window, trace the left renal vein from kidney to IVC. Click the "key" icon under the transverse window. Hold the command or ctrl key as you click the up or down arrows. You will need to click through a number of slices. What anomaly do you find?
27. Dissect the kidney. The vasculature of the kidney will remain. Manipulate the various cross-sectional windows to reveal the cortex, medulla, and (with imagination) the major and minor calyxes.
To remove the kidney, you will need to clamp the renal artery(ies) and vein. Which should you clamp first and why?
Arteries are clamped first. If veins were clamped first. blood pressure would increase in the kidney.
28. Dissect the transversalis fascia and interperitoneal fat. (This will also remove the thin peritoneum, the lining of the peritoneal cavity.) Now for the first time you can see the various segments of the gastrointestinal tract.
The beauty of this procedure is that the surgeon avoids entering the peritoneal cavity. Why is this an advantage?
The postoperative complication of a peritoneal infection (peritonitis) is avoided.
29. Mouse around the various windows and take note of the relationships of the kidney.
The surgeon would want to avoid all the back muscles that you just removed. He or she would enter the retroperitoneal space just lateral to the quadratus lumborum and approach the kidney posteriolaterally. Needle biopsies would follow the same path.
When performing this procedure the surgeon should be aware of the following important anatomy: