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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_731_Библиотеки_им_академика_М_И_Перельмана.pdf
1. Clinical Anatomy
C HAPT E R
9
Periumbilical Perforator
Sparing Components
Separation
George DeNoto III, MD, FACS and Ron Israeli, MD, FACS
1. Rationale for Sparing the Periumbilical Perforators
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Components separation for ventral hernia repair requires release of the external oblique
muscle lateral to the linea semilunaris and separation of the avascular plane deep to the
external oblique. This allows midline advancement of the rectus abdominis in continuity with the internal oblique and transversus abdominis muscles. As originally described,
components separation requires wide undermining of the skin and subcutaneous layer to
adequately expose the external oblique muscles for subsequent division. Consequently,
perfusion of the undermined skin flaps can be compromised, which increases the risk of
skin flap necrosis, infection, and dehiscence. In addition, extensive elevation of abdominal
skin flaps creates a large wound surface predisposing to postoperative hematomas and
seromas.
To address this major shortcoming of conventional components separation, a modified
technique of elevating partial subcutaneous flaps with preservation of the periumbilical
perforating vessels arising from the inferior epigastric vessels can be performed. The rationale for using the technique of periumbilical perforator sparing (PUPS) components separation is to maximize skin blood supply. The preservation of blood flow to the midline
abdominal wall should minimize complications, especially skin flap ischemia and infection. In addition, by avoiding wide undermining, subcutaneous dead space is minimized,
which may reduce the incidence of seromas or hematomas. Furthermore, preservation of
blood supply to the abdominal wall in ventral hernia repair allows expanded applications
for patients with obesity, diabetes mellitus, a recent smoking history, and for those with
stomas as well as those who require concomitant panniculectomy.
139
140 Section IV • Component Separation
2. Innervation and Blood Supply to the Abdominal Wall Muscles
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3. Blood Supply to the Abdominal Wall Skin
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In performing all techniques of components separation abdominal wall reconstruction, it
is important to understand the musculofascial anatomy, innervation, and blood supply of
the anterior abdominal wall. The anterior and posterior releases in components separation
allow preservation of the blood supply and innervation of the abdominal wall muscles.
The intercostal neurovascular bundles that contribute to the external oblique, internal
oblique, transversus, and rectus muscles are preserved because they run deep to the internal oblique. They are therefore preserved during all techniques of components separation.
In addition, the deep inferior epigastric vessels and the superior epigastric vessels, which
run in a longitudinal orientation deep to and within the substance of both rectus muscles,
are also preserved regardless of which components separation technique is performed.
Preservation of these vessels maintains the blood supply to the abdominal wall muscles.
On the other hand, blood supply to the overlying skin relies on branches of these ves-
sels, as well as on a number of additional vessels, which are preserved to varying degrees,
depending on the technique of components separation performed.
The blood supply to the abdominal wall skin is based on direct cutaneous vessels in addi-
tion to numerous branches of deep vessels that are known as musculocutaneous perforators. Whenever abdominal wall skin is undermined, as in components separation, defining
the source of vascularity to the remaining skin in critical.
The three Huger zones of abdominal wall vascular anatomy can help guide the surgeon
in planning a safe abdominal wall operation. Huger zone I, the central abdominal wall,
is supplied by the deep inferior epigastric and superior epigastric vessels. Zone II, the
lower abdominal wall, is supplied by the superficial inferior epigastric, superficial external
pudendal, and superficial circumflex iliac arteries. Zone III, the lateral abdominal wall,
is supplied by the intercostal, subcostal, and lumbar arteries. Skin flap elevation during
conventional components separation abdominal wall reconstruction results in complete
division of the cutaneous blood supply of Huger zone I, supplied by the deep epigastric
vessels. The PUPS components separation approach preserves the vessels of Huger zone I,
which allows improved perfusion to minimize any potential vascular related complications.
The concept of vascular territories called angiosomes further elucidates our understanding
of the blood supply to the abdominal wall skin. From a clinical perspective, preservation of
the primary angiosome to an anatomic territory of skin maximizes blood flow to that territory. The primary central anterior abdominal wall angiosome is supplied by multiple cutaneous perforator branches of the deep epigastric artery system. Microdissection analysis
of the vascular anatomy of the anterior abdominal wall skin and subcutaneous tissue has
confirmed that perforator branches of the deep inferior epigastric vessels provide the main
blood supply to this region. More specifically, the periumbilical region, mostly just inferior
and lateral to the umbilicus is the region with the highest concentration of these perforator
vessel branches (Fig. 9-1). The PUPS components separation technique focuses on maintaining this rich vascular network, thereby maximizing blood supply without compromising the degree of muscle flap advancement possible.
Chapter 9 • Periumbilical Perforator Sparing Components Separation 141
Normal
Periumbilical
perforator branches
Displaced
rectus muscles
Hernia sac and fascial defect
Hernia sac protruding
through fascial defect
Previous old scar
Periumbilical
perforator branches
Figure 9-1.
Deep inferior epigastric arteries
142 Section IV • Component Separation
2. Preoperative Considerations
1. Optimization of Comorbidities
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2. Defining the Defect and Patient Anatomy
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Preoperative Physical Examination
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The primary goal in the management of the ventral hernia patient is to repair the hernia
while minimizing the incidence of postoperative complications, including recurrence. As
with any surgical procedure, preoperative patient optimization is vital to reducing the
risk of postoperative complications. This includes smoking cessation, control of diabetes
mellitus, weight loss, maximization of nutritional status, establishing an exercise routine,
preoperative Staphylococcus aureus screening, and optimization of pulmonary and cardiac
status.
A focused preoperative physical examination is very important in planning the operative
approach in abdominal wall reconstruction and helps identify the appropriate candidate
for PUPS components separation. Components separation procedures are useful for midline and paramedian hernias in which the fascia cannot be approximated without flap
release and advancement. In general, components separation can allow fascial approximation for most midline defects smaller than 20 cm at the waistline.
The size of the defect and loss of domain can be estimated by physical examination. The
combination of a large hernia sac and a large hernia defect are the typical findings on exam
that may predict the need for a components separation. A large sac with a small defect
frequently does not require a components separation procedure to obtain fascial closure,
whereas a large defect with a small sac may. However, there is no exact size of defect that
predicts the need for a components separation procedure because abdominal wall compliance varies from patient to patient.
Preoperative surgical scars and the position of any stomas, if they are present, should be
noted. This can help in surgical planning of a PUPS procedure.
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Preoperative Abdominal CT Scan
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Preoperative imaging studies also are useful in planning the operative procedure. A preop-
erative computed tomography (CT) scan provides an accurate measurement of the size of
the ventral hernia defect and can demonstrate the size and contents of the hernia sac (Fig.
9- 2). This information can help predict the need for a components separation procedure.
A CT scan also may reveal the presence of any other hernia defects or other pathology otherwise not appreciated on physical examination. Other hernia defects potentially identified
on a CT scan can then be addressed at the time of abdominal wall reconstruction.
Chapter 9 • Periumbilical Perforator Sparing Components Separation 143
lm:56 Study date: 5/23/2008
Study time: 8:47:35 AM
MRN:
[R]
Figure 9-2.
[L]
144 Section IV • Component Separation
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3. Choosing the Type of Components Separation
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In patients who have had a prior wide subcutaneous flap procedure or other abdominal
surgery where the periumbilical perforator blood supply to the abdominal wall may have
been divided, a CT angiogram can be performed. CT angiography can identify the remaining blood supply to the central abdominal wall in order to help operative planning. The
location of intact perforators can be identified preoperatively and thereby preserved during
PUPS components separation.
The technique of PUPS can be performed in essentially any patient thought to be a candi-
date for components separation.
In all cases, the choice is made between two categories of components separation proce-
dures: those that preserve the periumbilical perforators and those that do not. While this
choice can be made preoperatively, the final selection of procedure may rely on findings at
the time of surgery.
The conventional components separation (as described in Chapter 8) requires significant
skin undermining and division of the periumbilical perforators and should be performed
only if extensive subcutaneous skin flap elevation is necessary (i.e., as done during removal
of an infected onlay synthetic mesh). Otherwise a periumbilical perforator sparing technique, performed open or laparoscopic should be attempted in all cases requiring components separation.
Procedures that preserve the periumbilical perforators include the open PUPS components
separation and the laparoscopic components separation procedures.
Chapter 9 • Periumbilical Perforator Sparing Components Separation 145
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4. Choosing the Type of Mesh
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If dissection and removal of the hernia sac results in partial subcutaneous flap creation then
one should continue that dissection around the periumbilical perforators and perform an
open PUPS components separation. If there is no skin flap creation during removal of the
hernia sac then a laparoscopic components separation can be performed (as described in
Chapter 11).
One of the limitations of the laparoscopic components separation technique is that it may
not always provide the same degree of fascial release as compared to conventional components separation. In our experience, the extent of fascial release provided by open PUPS
components separation is equivalent to the degree of release possible with the conventional open approach.
Mesh placement is strongly advised once the PUPS components separation procedure is
completed in order to minimize post operative hernia recurrence.
In the patient with multiple comorbidities, who is at higher risk for developing a postoper-
ative surgical site infection, the implantation of a biologic matrix to reinforce fascial closure
after components separation may be more appropriate than a synthetic mesh. Similarly,
if the patient has a clean-contaminated or contaminated wound, then a biologic matrix
should be implanted. A patient with minimal or no comorbidities and a clean operative
wound class can have a synthetic mesh implanted for fascial reinforcement. If the wound is
too contaminated or dirty, then mesh implantation should be avoided and a staged repair
with mesh implantation at a later date should be considered.
146 Section IV • Component Separation
3. Operative Steps
1. Hernia on Physical Exam (Fig. 9-3 and Fig. 9-4, A)
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2. Preoperative Markings (Fig. 9-4)
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The patient is examined and the hernia defects and surgical scars are noted.
Before surgery, the patient’s abdominal wall is marked. The hernia defect is outlined, and
the locations of the periumbilical perforators are marked in reference to the rectus abdominis muscles (Fig. 9-4, B). The perforators are usually located within a 6 cm radius of the
umbilicus but can be more laterally positioned in the presence of a large hernia sac.
The planned subcutaneous tunnels along each costal margin and each inguinal region are
drawn on the abdomen.
All old incision lines are identified and marked. The planned skin incisions are marked,
including any planned excisions of old scar and excess skin (Fig. 9-4 C).
The planned transection of the external oblique aponeurosis will be within the connecting
tunnels on each side. Panniculectomy incisions can be marked if planned to occur simultaneous with the PUPS components separation.
3. Patient Positioning
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Whenever possible, an epidural catheter is placed. The patient is then positioned on the
operating room table supine with the arms abducted. Following induction of anesthesia,
an orogastric tube and Foley catheter are placed.
Chapter 9 • Periumbilical Perforator Sparing Components Separation 147
Figure 9-3.
A B C
Figure 9-4.
148 Section IV • Component Separation
4. Exposure
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5. Adhesiolysis
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6. Assessment of Fascial Approximation and Tension
The old scar and subcutaneous tissue posterior to the scar is excised. This is performed
usually en bloc with the ventral hernia sac (Fig. 9-5, A). Care is taken during dissection of
the ventral hernia sac not to undermine too widely from the sac in order to avoid injury to
the periumbilical perforators. Once the dissection is completed to the edge of the fascial
defect, the hernia sac is opened and excised (Fig. 9-5, B).
Any adhesions to the hernia sac and posterior abdominal wall must be fully lysed. If the
patient has a history of adhesive small bowel obstruction, then all intraabdominal adhesions are lysed and consideration is given to placement of an antiadhesion material. Any
concommitant intraabdominal procedure is performed at this time if necessary.
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Assessment of fascial approximation is performed by placement of two or three Kocher
clamps on each medial fascial edge (Fig. 9-5, C). If the fasciae can be easily approximated with minimal or physiologic tension then a components separation is not required.
If the fascial edges do not approximate easily, then a components separation should be
performed.