PROCEDURE

CLINICAL EXERCISE - Tube Thoracostomy

2. Interventions through the thoracic wall to gain access to the lung spaces are common lifesaving procedures following lung collapse. The concept of chest drainage dates back to Hippocrates himself who described a drainage procedure using metal tubes.

In this clinical exercise, you have the chance to insert a chest tube to your donor in a mock surgical intervention.

For the steps to take:
                             ------ click here ------

3. Before cutting into the skin, review the markings on your donor from the prior lab session as we will use these as part of the planned incision lines.
    (Figure242) (Rad1001)

The incision plan will use your previously marked midsternal, clavicle, axilla, and costal margin landmark lines. These incision marks demarcate a left and right anterior thorax skin flap which will be reflected in the following steps.

Successful outcome of surgical procedures is, logically, strongly correlated with the surgeon getting the initial incisions in the correct place.

4. Start at the jugular notch following your incision marking, make a deep 'to-the-bone' incision in the skin at the midline extending the full length of the anterior surface of the sternum. 
    (Figure243)

Use the traction and counter-traction method from the skin incision foundational skills video in the pre-lab section above. 

This is a safe zone for a deep incision as there are no nerves or vessels crossing from the left to right side at the midline and the sternum protects thoracic structures from the incision.

If you have not already reviewed the video on skin incisions, take a moment to review the video instruction section with this link.  ---- click here ---->

5. Make a second incision several millimeters in depth following the full length of the clavicular incision marking so that you now have a T shaped incision.
    (Figure243a)  

The traction and counter-traction method results in the incision opening slightly during cutting allowing a visualization of the depth of the cut. The cut can always be deepened later if the initial incision is too shallow.

6. Make a third incision quiet shallow in depth following just superior to the costal margin incision marking all the way to the mid-axillary line.
    (Figure243b)

Make this incision shallow and ensure that the incision is superior to the costal margin.

It is important not to cut through the anterior abdominal wall. Thus, by making the cut just superior to the costal margin the abdomen is protected against cutting too deeply.

7. Make a fourth incision several millimeters in depth following the deltopectoral groove marking on the anterior thorax.
    (Figure243c)

Avoid cutting too deeply along this line as excessive depth may transect part of the pectoralis major muscle. A shallow cut can always be deepened later.

7. Using a hemostat (locking forceps), at the superior end of the midsternal incision clamp the skin at the corner where the incision lines intersect and pull the corner of skin, so that you can make small incisions under the lifted edge to reflect the skin. 
    (Figure244)

If you have not already reviewed the video on skin reflection, take a moment to review the video instruction section with this link.  ---- click here ---->

8. Widen and deepen the cut until you reach the plane between the superficial (hypodermis) and deep fascia covering the muscles.
    (Figure103)

Fascia and any other human tissues removed from your donor should be placed into one of your Emerson basins for disposal in the marked human-tissue biohazard containers (these are by the lab central pillars). There is already a biohazard bag liner in the bin so you do not need to place tissues for disposal into a separate biohazard bag. Do not place human tissues into the regular trash or the glove disposal boxes.

At this point you can observe the depth of the cut and identify the layers of the integument (skin). From superficial to deep these layers are the epidermis, dermis, and hypodermis.

The mammary gland tissue lies in the superficial (hypodermis) fascia. (Netter188) 

Epidermis: The epidermis is only a few hundred micrometers in thickness and will exhibit different degrees of pigmentation depending on the individual.

Dermis: The dermis is a stronger layer of connective tissue (dense irregular connective tissue) up to several millimeters thick that is fused tightly to the epidermis. To the eye, the dermis typically exhibits a relatively uniform pale color.

Hypodermis: The hypodermis varies widely in thickness depending on the region of the body and body habitus of the individual. At the midline it may range from a few millimeters up to a centimeter while thickness in the lower torso can be several inches.

The hypodermis in a well nourished individual will have yellow adipose connective tissue regions interspersed with fibrous connective tissue. Within the hypodermis are numerous small blood vessels and nerves (most of these are microscopic in size).

The deep or investing fascia is not considered part of the integument organ (i.e. the skin). Deep fascia surrounds and encases muscles of the body (thus the alternate term 'investing' fascia).

On the torso, the deep fascia layer lies immediately below the hypodermis and directly on the surface of the pectoralis major muscle.

Deep fascia is a very thin layer that typically has a white smooth membranous appearance. Muscle tissue underneath the deep fascia is darker and has a distinct appearance consisting of parallel fascicles.

Each of these fascicles is formed by bundles of individual muscle cells. On the torso, where you are dissecting, these muscle fascicles belong to the pectoralis major muscle (we will examine the pectoralis major muscle in detail later in the lab).

9. Use your hemostats to apply continuous tension as you retract the skin and separate along the plane between the superficial fascia and the deep fascia.
    (Figure244a)

If you find yourself cutting into muscle tissue you are dissecting too deeply and need to move shallow back to the correct plane.

Stay along the surface of the muscle (deep fascia) so as to be able to preserve the breast tissue intact.

Hold the scalpel at an angle and use smooth slicing motions to cut with the tip of the blade. Each cut should aim to separate a few millimeters of tissue, allowing you to observe what you are cutting while making the incisions.

Sawing motions are to be avoided. Sawing has less control and can result in jagged edge cuts that, in the living, may not heal as well as smooth cuts. Commonly in surgery we would use electrosurgical cutters that simultaneously cut and cauterize.

In some regions pushing your fingers into the plane between the superficial and deep fascia will separate the tissue along the fascial plane.

It may help to have a member of the team keep tension on the skin while a second member is cutting. Once there is room to work safely, dissection can proceed simultaneously on the left and right side of the donor.

10. Reflect the skin following along the superior and inferior incision lines out to the mid-axillary line.
    (Figure244b)

As you reflect the skin take care to follow the plane between the superficial fascia (hypodermis layer) and the deep fascia covering the chest plate and the pectoralis major muscle such that you can reflect both breasts and surrounding integument.

The breast and surrounding skin area should be free of any attachments along the medial, superior and inferior regions, with the only attachment along the lateral edge at the mid-axillary line.

11. Place the breast flap back into position and on only one of the breasts make a parasagittal cut through the nipple and areola several inches in length.
    (Figure204) (Photo2072)

Recall, a parasagittal incision is one that runs superior to inferior, or if using the clock facer nomenclature of the breast from 12 o'clock to 6 o'clock.

If you had identified and marked a possible breast mass or region of concern, then change the axis of the incision such that it passes through the region of concern.

This will allow examination of the mass and potential biopsy of the tissue for pathology assessment.

12. Use a Weitlaner retractor to spread the skin incision to observe the exposed surface of the hemisected breast.
    (Photo2073)

The exposed surface of breast will have adipose tissue (yellow) and pale fibrous septa of the suspensory ligaments of the breast (also known as Cooper's ligaments).

13. With a blunt probe remove some of the adipose tissue and observe that the suspensory ligaments of the breast form a honeycomb like arrangement of fibrous sheets.
    (Figure211) (Netter188) (Photo2074)

The suspensory ligaments of the breast serve a structural support function, tethering the skin of the breast to the deep fascia and supporting both glandular and adipose tissue of the mammary gland.

In the male, suspensory ligaments of the breast are absent or rudimentary in structure.

14. Probe the connective tissue near the nipple and note the appearance of 'striations' representing the terminal elements of the breast duct system, the lactiferous ducts and sinuses.
    (Figure211) (Figure212) (Netter188) (Photo2075)

In males, ducts from the nipple are very short and rarely extend beyond the boundary of the areola.

In females, a system of ducts extends from the nipple into the surrounding stroma (body) of the breast. This system of ducts in the aged breast is less well defined than in a younger individual, as they undergo an involution process with age.

Any striation line or strand like structure from the nipple will be a remnant of the lactiferous duct system.

The female breast is divided into 15-20 irregular lobes of glandular tissue. The glandular tissue of each lobe leads to a single lactiferous duct terminating in a small swelling, a lactiferous sinus, just before openings at the nipple.

Lobes are organized in a roughly radial manner around the nipple. However, it is not possible to visualize a lobe clearly as duct branches can cross and interweave with those of an adjacent lobe.

15. When you have completed the examination of the breast of your donor you will swap tables briefly so that you can examine the breast of the opposite sex.

Remember to review the Patient chart at your swap table so that you know the name of the donor and any clinical notes entered by the other team before your examination them.

SWAP POINT: At this point, swap with your pre-identified table containing a donor of the opposite sex and go through the steps above examining the breast structure. Then return to your donor to continue steps below.
    --------> click here for (Laboratory Swap Map). 

16. When you have finished examination of the other table, return to your table and remove the Weitlaner retractor.

17. Reflect the thoracic skin flaps laterally so that you can observe the surface of the pectoralis major muscle.

18. Clean the surface of the pectoralis major muscle and observe its clavicular, sternal, and costal attachments.
    (Netter194) (Photo2001) 

The pectoralis major muscle forms up the bulk of the chest musculature with the breast positioned anterior to the muscle anchored to the pectoral fascia (deep fascia on the surface of pectoralis major).

19. Force your fingers deep to pectoralis major along its inferior border (about the 4th or 5th rib on the lateral chest wall) and mobilize the inferior edge by lifting superiorly.
    (Figure205) (Photo2076)

The inferior edge is frequently tightly bound in fascia. Thus, you may need to make a small scalpel cut to start the opening under the muscle edge.

Do not cut near the costal margin as you may damage abdominal wall musculature that we will be studying in a later lab session.

20. Sever the pectoralis major muscle costal attachment, the sternal attachment, and approximately halfway along the clavicular attachment.
    (Figure205, cut lines) (Photo2077) (Photo2078)

21. Reflect the pectoralis major muscle laterally and superiorly, using fingers to gently separate the muscle from underlying structures.
    (Figure206a) (Photo2079)

On the deep surface of the pectoralis major muscle the medial pectoral nerve enters the muscle. If you are gentle in separating and reflecting the muscle, your fingers will find a tough 'strand' or 'string' like structure which is the nerve.

Under the superior edge of pectoralis major, near the clavicle, are additional nerves and vessels entering the muscle (you saw the location of these in the introductory techniques videos). We will not dissect this area today, as that is part of another session.

22. Fully reflect the pectoralis major muscle and observe the underlying pectoralis minor muscle.
    (Figure206a) (Netter195) (Photo2080)

As you uncover pectoralis minor, if you found the medial pectoral nerve trace it proximally and observe that the nerve pierces through the pectoralis minor muscle before entering the pectoralis major muscle.

23. When you have finished the laboratory dissection for today, return the reflected pectoralis muscles to their correct position and return the reflected breast skin regions back into position covering the thorax.

DONOR CARE

Then proceed with donor care, covering the donor with the moist cloth, closing the inner plastic liner and securing with several hemostats, zipping up the white plastic outer bag, and neatly covering the donor with the blue drape.

Remember to check the drain bucket under your table and if needed follow the emptying procedures from the previous lab (first fetch an empty bucket from the shelving near the fluid disposal drums, swap out your bucket for the empty bucket, then empty your bucket into the drum and leave the now empty bucket on top of the drum for the next group).

CHECKLIST

Skeletal Structures

Sternum
    Manubrium
    Body of the sternum
    Xiphoid process
    Sternal (jugular) notch
    Sternoclavicular joint

Ribs
    Costal margin
    Sternocostal joints

Soft Structures

Breast
    Nipple
    Areola
    Suspensory (Cooper's) ligaments
    Lactiferous ducts

Pectoralis major muscle

Pectoralis minor muscle

Medial pectoral nerve