Repair of Flank and Lumbar Defects



Repair of Flank and Lumbar Defects


Sergey Y. Turin

Chad A. Purnell

Gregory A. Dumanian





ANATOMY



  • The lateral and lumbar abdominal wall is composed of three load-bearing muscular layers and their respective fascial envelopes—the external and internal oblique and the transversus abdominis. All three of these can be compromised by an incision for retroperitoneal access. Discontinuity of these layers would lead to a hernia defect. (See the chapter on “Synthetic and Biologic Mesh for Abdominal Wall Defects,” FIG 1, for example.)


  • The muscles of the abdominal wall are segmentally innervated by the 7th through 12th intercostal as well as the iliohypogastric and ilioinguinal nerves running between the transversus abdominis and the internal oblique muscles. In this plane, they are vulnerable to transection during a retroperitoneal approach for incisions that cross dermatomes. They are also susceptible to focal injuries from retractors, cautery, and abdominal wall full-thickness sutures (FIG 1).



PATHOGENESIS



  • True hernias occur when the ultimate tensile strength of the repair is less than the forces applied. Acutely, the sutures can tear through the abdominal muscles during coughs and forceful movements and lead to a dehiscence or evisceration. Chronically, tissue located within the loop of suture becomes scar. When the strength of the scar, sutures, and foreign body reaction to those sutures is less than the forces applied, an incisional hernia develops. In comparison to incisional hernias, flank bulges are due to denervation of the abdominal wall. Narrow zones of denervation with loss of just one or two intercostal nerves during the original surgery do exist, often due to resection of spinal cord roots for exposure or tumors. Alternatively, there can be a large zone of denervation from a profound spinal injury. The larger the zone of injury, such as with a spinal cord injury, the less the techniques in this chapter apply.


  • With maneuvers that are intended to stabilize the torso such as the Valsalva maneuver, the viscera instead distend the flank defect and cause a disagreeable and sometimes painful contour irregularity. Patients complain of discomfort due to an inability to raise their intra-abdominal pressure and altered torso mechanics—a loss of “core strength.”


  • See the chapter on “Abdominal Hernia Reconstruction” for a discussion of the biomechanics of the abdominal wall and the importance of evaluating abdominal wall compliance when dealing with these defects.


NATURAL HISTORY



  • These defects can often be a cause of marked pain and lead to functional impairment with diminished quality of life.5 The plastic surgeon will usually see the patient in a delayed setting, with the consultation being prompted by worsening symptoms.


PATIENT HISTORY AND PHYSICAL FINDINGS



  • Patients are encouraged to obtain all the previous operative notes, and it is important to record if a rib was resected at the original procedure. Hernias present for many years are more difficult to close than a hernia less than 1 year from the index surgery. It is of great importance to discuss the medical history and comorbid conditions, such as COPD, diabetes, cardiac disease, and any rheumatoid conditions.


  • Prior incisions are recorded, and an evaluation of skin quality and abdominal wall compliance is made. The patient is asked to stand as well as to lie in the lateral decubitus position to clarify the borders and size of the defect. Palpate the bulge with an eye toward feeling any muscle contraction or edge to the defect to gain an idea of whether the remaining muscle is innervated and continuous. Look for incisions of the midline back that denote spine pathology and possible denervation.


  • A social history is important to appreciate the stresses on the torso required to return to work or important social activities.


IMAGING



  • We routinely obtain a CT scan of the abdomen using oral and IV contrast to assess the layers of the abdominal wall, to measure the size of the defect, and to screen for any other intra-abdominal pathology (such as a recurrent cancer) as dictated by the patient’s history. Any midline hernias would be documented (though typically not addressed) at the time of the flank repair (FIG 2).






FIG 2 • CT Scan of a patient with a flank hernia.


NONOPERATIVE MANAGEMENT

Dec 6, 2019 | Posted by in Reconstructive microsurgery | Comments Off on Repair of Flank and Lumbar Defects
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