Atlas of General Surgical Techniques (Courtney M. Townsend Jr., B. Mark Evers)

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STEP 2: PREOPERATIVE CONSIDERATIONS FOR FOREARM

Compartment syndrome is a surgical emergency that usually requires release of the superficial muscle compartments. In some clinical situations, it is imperative to also explore the deep muscle compartments.

Forearm compartment syndrome requires immediate evaluation and treatment. The need for operation is established by careful review of the patient’s history; the presence of physical signs and symptoms, such as pain with passive stretching, paresthesias, paresis, and palpably tense compartments; and, if needed, the measurement of elevated compartment pressures ( 30 cm H2O).

The treatment of compartment syndrome requires expedient fasciotomy when nonoperative maneuvers such as cast removal are unsuccessful. If left untreated, elevated tissue pressure within the fascial confines decreases capillary blood perfusion below a level necessary for soft tissue viability. Most patients ultimately have minimal limb dysfunction when fasciotomy has been performed promptly and to an adequate depth. Postoperative loss of function may be caused by several factors, including damage from the initial injury, ischemia caused by elevated tissue pressure before fasciotomy, inadequate fasciotomy, and iatrogenic surgical injury.

Mandatory exploration of deep muscle compartments is indicated in situations in which the deep muscles are preferentially injured, such as in cases of high-voltage electrical injury. The high electrical resistance of bone transmits a significant thermal injury to the adjacent muscles of the deep compartment. Other conditions that require exploration of the deep spaces include severe crush injuries; situations involving extended pressure, such as an unconscious patient lying on the limb; and when there is ongoing sepsis or suspicion of necrotic muscle, despite previous fasciotomy. If epimysiotomies of the deep muscles are not performed in these situations, necrosis and contracture may result.

Limited incisions to minimize collateral morbidity from fasciotomy do not offer access to all components and increase the potential for missing an ischemic or necrotic muscle group.

STEP 3: OPERATIVE STEPS FOR FOREARM

1. INCISION

A commonly used approach, begins 1 cm proximal and 2 cm lateral to the medial epicondyle. The incision is carried obliquely across the antecubital fossa and over the volar aspect of the mobile wad and is then curved medially to reach the midline of the forearm at the junction of its middle and distal thirds. The incision is continued straight distally to the proximal wrist crease ulnar to the tendon of the palmaris longus and is finally curved across to the midpalm (Figure 87-1, B).

2. DISSECTION

The subcutaneous tissues are divided to expose the deep fascia, and individual muscles are mobilized for examination (Figure 87-1, C).

If the muscles of the dorsal compartment require release after the volar fasciotomy, a straight longitudinal incision is made below the lateral epicondyle toward the midline of the wrist.

Other incisions described for the treatment of compartment syndrome criss-cross the forearm or gently sweep across it in various directions.

Incisions that cross the forearm will transect more of the venous and lymphatic return than will a straight incision, and the resolution of forearm edema could be impaired. Such incisions may also prevent the future design of a radial forearm flap, because the vascular supply and outflow of the skin pedicle would be compromised.

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3. CLOSING

Dressings

Cover the wound with saline-soaked gauze and a nonconstricting bandage.

STEP 1: SURGICAL ANATOMY FOR LEG

The lower leg has four muscular compartments with dense investing fascia that contribute to the predisposition of this region to develop neurovascular compromise following injury generally referred to as compartment syndrome.

The treatment of compartment syndrome requires incision of the investing fascia of all four compartments: anterior, lateral, superficial posterior, and deep posterior (Figure 87-2, A).

STEP 2: PREOPERATIVE CONSIDERATIONS FOR LEG

Same as previously mentioned for the forearm procedure.

STEP 3: OPERATIVE STEPS FOR LEG

1. INCISION

Medial and lateral skin incisions are carried from just proximal to the medial and lateral malleoli and carried cephalad to the level of the tibial plateau medially and the fibula head laterally, where care must be taken to avoid injury to the peroneal nerve (Figure 87-2, B).

2. DISSECTION

Both the superficial and deep posterior compartments are released through the medial incision, and the anterior and lateral compartments are released through the lateral incision

(Figure 87-2, C).

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3. CLOSING

Dressing of saline-soaked gauze and a nonconstricting bandage.

STEP 4: POSTOPERATIVE CARE

Pain control is often a significant issue following fasciotomy and is best managed with a patient-controlled analgesia device. Wound care requires attention to aseptic technique and ensures adequate material: sterile gowns, gloves, and dressing supplies are at hand before dressing changes are begun to avoid contamination and serious morbidity associated with wound infection. Elevation of the extremity will help reduce edema and hasten the recovery and closure of the wound. The use of biologic dressings, either homograft or xenograft, may also help in wound care.

STEP 5: PEARLS AND PITFALLS

Most cases of compartment syndrome are adequately treated by release of the superficial volar compartment, regardless of which surgical approach is chosen. Those clinical situations that mandate exploration of the deep volar or dorsal compartments, however, require a significant understanding of anatomy to follow a surgical approach that will minimize further injury. Clinical examples include high-voltage electrical injury, severe crush injuries, extended extrinsic forearm pressure (such as an unconscious patient lying on his or her forearm), and ongoing evidence of myonecrosis or sepsis despite previous superficial fasciotomy. In some cases, even after compartment fasciotomy, the epimysium of individual muscles must be incised to relieve persistently elevated tissue pressure. This can be achieved only with adequate visualization of the deep space.

SELECTED REFERENCES

1.Lagerstrom CF, Reed RL Jr, Rowlands BJ, Fischer RP: Early fasciotomy for acute clinically evident posttraumatic compartment syndrome. Am J Surg 1989;158:36-39.

2.Dente CJ, Feliciano DV, Rozycki GS, et al: A review of upper extremity fasciotomies in a level I trauma center. Am Surg 2004;70:1088-1093.

C H A P T E R 88

RENAL REVASCULARIZATION

Glenn C. Hunter

Approximately 5% to 10% of patients with hypertension have renal artery stenosis (RAS) as the underlying cause. Atherosclerotic occlusive disease in individuals older than 65 years and fibromuscular dysplasia (FMD) in children and young adult females (20 to 40 years of age) are the most common etiologies. Atherosclerosis of the renal arteries is usually confined to the orifice and proximal third of the involved vessel (more commonly the left) and should be considered as an extension of aortic atherosclerosis. In 20% of patients with RAS, there is severe associated aortic aneurysmal or occlusive disease, which determines the extent and type of procedure to be performed. RAS may occur in isolation (anatomic stenosis) or in association with hypertensive ischemic nephropathy. FMD may be medial (85%), perimedial (10%), or intimal (5%) and usually involves the mid-portion of the main renal arteries and their segmental branches.

STEP 1: SURGICAL ANATOMY

The renal arteries branch laterally from the aorta below the origin of the superior mesenteric artery. There is usually a single renal artery to each kidney. The right renal artery arises higher and is longer than the left renal artery. The right renal artery runs posterior to the inferior vena cava, right renal vein, head of the pancreas, and descending part of the duodenum to the renal hilum. The left renal artery passes posterior to the left renal vein, body of the pancreas, and splenic vein. Multiple renal arteries are present in up to 35% of patients and should be identified and evaluated before any surgical intervention.

STEP 2: PREOPERATIVE CONSIDERATIONS

Medical history, physical examination, and assessment of renal and cardiac function should be performed in all patients. Features suggestive of RAS as the cause of hypertension include hypertension of abrupt onset, hypertension refractory to medical therapy (more than three drugs), unexplained azotemia or azotemia induced by angiotensin-converting enzyme (ACE) inhibitors, and hypertension in children and young adults.

Screening and diagnostic studies: Duplex ultrasound is useful as a screening test for RAS and evaluation of kidney size. Interrogation of the renal arteries from their origin to the hilum can be achieved in 95% of cases. A peak systolic velocity of greater than 180 cm/sec and renal-to-aortic ratio 3.5 with distal turbulence is usually indicative of a hemodynamically significant stenosis ( 60%). Occlusion of the renal artery is usually identified by the absence of a Doppler signal.

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Computed tomography (CT) or digital angiography is used to delineate the stenosis before intervening. There is a high risk of contrast-induced nephrotoxicity, and care should be taken in performing these studies in patients with renal impairment. The administration of intravenous (IV) fluids (1.5 mL/kg/hr), limiting the dose of or diluting the contrast agent, and the administration of acetylcysteine 600 mg orally before and after the contrast procedure are among the measures used to reduce the risk of nephrotoxicity. Magnetic resonance angiography is an alternative method of assessing RAS in patients with a glomerular filtration rate 30 ml/min/1.73 m2.

Functional studies: A captopril renal scan may be helpful if there is unilateral stenosis and minimal parenchymal disease. The significance of unilateral RAS should be confirmed by plasma renin determinations. This may require admission to the hospital, withholding medications that interfere with renin release, and sodium restriction ( 2 g Na /day) for approximately 2 weeks.

Indications for the operative treatment of RAS include stenosis greater than 70% with poorly controlled hypertension, renal insufficiency, or recurrent bouts of congestive heart failure (CHF) with no attributable myocardial ischemia. Patients with branch vessel disease and FMD and selected patients with restenosis after angioplasty and stenting may be candidates for surgery.

STEP 3: OPERATIVE STEPS—AORTORENAL BYPASS

The patient is admitted the day before the procedure for IV hydration, control of blood pressure, and a mechanical bowel preparation. Antihypertensive medications should be reduced to the minimum necessary to control the blood pressure. If the diastolic blood pressure is higher than 120 mm Hg, the patient should be admitted to the intensive care unit (ICU) and the blood pressure controlled with IV sodium nitroprusside or nicardipine.

1. INCISION

A midline or transverse incision allows both access to the renal arteries and reconstruction of associated aortic disease if required. The abdomen is explored, the transverse colon and small bowel are lifted out of the abdomen, and a self-retaining retractor such as the Omni-Tract system is placed (Figure 88-1, A).

2. DISSECTION

The peritoneum over the aorta is incised in the midline, and the dissection is carried down to the left renal vein superiorly and the aortic bifurcation inferiorly (Figure 88-1, B). The left renal vein is then mobilized and retracted cephalad or caudally depending on the location of the origin of the renal vessels. Retraction of the left renal vein is facilitated by ligation and division of the gonadal, adrenal, and lumbar veins.

Both renal arteries are then dissected out 2 cm beyond the orificial stenotic lesion. An aortorenal bypass is the most common revascularization procedure performed but requires clamping of the aorta. This technique is applicable only to patients with large paired renal arteries with minimal aortic atherosclerosis or aneurysmal dilation.

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The proximal right renal artery is exposed by retracting the left renal vein superiorly

and the vena cava to the right. The distal portion of the renal artery is exposed by mobilizing the duodenum and hepatic flexure medially. If both renal arteries need to be exposed, the entire small bowel is mobilized from the ligament of Treitz to the mesentery of the cecum and along the right paracolic gutter to the foramen of Winslow. The peritoneal incision is extended along the inferior border of the pancreas, exposing the aorta above the origin of the superior mesenteric artery.

Once the renal arteries have been isolated, a segment of the infrarenal aorta below the renal arteries is mobilized. After systemic heparinization (100 U/kg) and the administration of mannitol (12.5 to 25 g), the aorta is occluded below the renal arteries and above the bifurcation, and an ellipse approximately three times the diameter of the renal artery is excised from the anterior lateral aortic wall. Saphenous vein or a prosthetic Dacron or polytetrafluoroethylene (PTFE) graft 6 or 7 mm in diameter is beveled, and the aortic anastomosis is completed with 4-0 polypropylene suture (Figure 88-2, A-C).

Left Right renal vein

renal artery

Left

renal artery

Abdominal aorta

Inferior vena cava

A

FIGURE 88–2