Lumbar Microdiskectomy

Indications

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Appropriate patient selection is an essential element when planning spine surgery to optimize patient outcome. The decision to pursue surgery is based on the history, physical examination, and radiographic findings. Radiographic evidence of a disk herniation in the absence of corresponding clinical signs or symptoms is insufficient to warrant operative intervention.
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Radiculopathy that is secondary to compression of neural structures by a herniated disk and unresponsive to a trial of conservative therapy is the primary indication for performing a lumbar microdiskectomy.
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Less common but more emergent indications include acute or progressive neurologic deterioration and cauda equina syndrome.

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Asymptomatic herniated disk—lack of correlation between history, physical examination, and radiographic findings
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Improvement of symptoms with conservative therapy
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Segmental instability

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Preoperative medical clearance (including laboratory tests, chest x-ray, and electrocardiogram) should be obtained. An anesthesia evaluation may be needed if the patient has significant medical or pulmonary comorbidities. If medically appropriate, anticoagulants and antiplatelet agents should be discontinued before surgery.
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Antibiotics (gram-positive coverage) should be given at least 30 minutes before incision. Although not considered standard of care, a single dose of intravenous steroids can be administered in the presence of a neurologic deficit or sizable disk herniation.
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Following is a description of a lumbar microdiskectomy performed through a tubular retractor system.

Figure 81-1:

The patient is placed prone on the operative table using a Wilson frame or bolsters to promote lumbar flexion; this allows the abdomen to hang free to reduce intraabdominal pressure and reduce epidural bleeding. Appropriate padding is placed to prevent pressure neuropathies and avoid increases in intraorbital pressure. The arms are positioned no more than 90 degrees at the shoulder and the elbow joints. Lower extremity sequential compression devices are placed for venous thrombosis prophylaxis. In men, the genitalia are checked to avoid compression. A Foley catheter is generally not placed for single level diskectomy. Intraoperative imaging should be performed before skin incision to confirm the appropriate level.