Lumbar Microdiskectomy

Bradley Moatz, MD

P. Justin Tortolani, MD

Dr. Moatz or an immediate family member has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research-related funding (such as paid travel) from Globus Medical and Vertebral Technologies. Dr. Tortolani or an immediate family member has received royalties from Globus Medical; is a member of a speakers’ bureau or has made paid presentations on behalf of Globus Medical; serves as a paid consultant to or is an employee of Globus Medical and Integra LifeSciences; and has received research or institutional support from Globus Medical.

PATIENT SELECTION

Indications

Lumbar microdiskectomy is indicated in patients with a symptomatic lumbar intervertebral disk herniation (IDH) that is refractory to a reasonable trial of nonsurgical treatment.¹^,² Well-suited patients present with leg pain, or “sciatica,” that follows a clear-cut radicular pattern. A thorough history and physical examination can predict the level of the IDH before confirmatory imaging studies are obtained. Oral corticosteroids, nonsteroidal anti-inflammatory drugs, physical therapy, and lumbar epidural steroid injection at the level of the IDH or affected nerve root are nonsurgical measures that are commonly used to manage pain and loss of function.¹ Progressive loss of motor function (eg, footdrop) that interferes with the patient’s quality of life represents the strongest indication for surgery. Intractable pain despite nonsurgical treatment is the most common indication for microdiskectomy.

Contraindications

Lumbar microdiskectomy is contraindicated for patients in whom no evidence of an IDH is present on imaging studies. Particular attention should be paid to patients who present with a painless footdrop because the differential diagnosis for this entity is extensive: peroneal nerve palsy, tertiary syphilis, diabetic mononeuropathy, facioscapulohumeral dystrophy, stroke, multiple sclerosis, and amyotrophic lateral sclerosis. These entities should be considered when evaluating patients with a paucity of findings present on MRI. Greater trochanteric pain syndrome is a common cause of radiating leg pain that can mimic an L5 radiculopathy based on the location of pain in the gluteus and lateral thigh.³ Importantly, greater trochanteric pain syndrome is not characterized by radiation of pain below the proximal calf, and other neurologic symptoms (eg, numbness, tingling, motor weakness) and signs (loss of reflexes) are absent.

PREOPERATIVE IMAGING

Closed MRI represents the benchmark for identification of the location and size of a suspected herniated nucleus pulposus (HNP).⁴ Sagittal T2-weighted sequences (Figure 1, A) provide accurate identification of the level of the disk herniation as well as the degree of foraminal encroachment. In certain cases, it is possible to determine whether the disk herniation is subligamentous and whether it has migrated cephalad or caudad within the spinal canal. Axial T2-weighted sequences (Figure 1, B) allow the surgeon to determine whether the HNP is central, paramedian, subarticular, or far lateral. In the case of a far-lateral HNP, the axial T1-weighted images may demonstrate the HNP in better clarity because the fat outside the canal (high signal intensity) contrasts well with the low signal intensity disk material. Plain radiographs should be obtained before surgery to evaluate for deformity (scoliosis or spondylolisthesis) or a spina bifida occulta, which may not be evident on MRI obtained in the supine position.

VIDEO 104.1 Lumbar Microdiskectomy. Bradley Moatz, MD; P. Justin Tortolani, MD (30 min)

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Video 104.1

PROCEDURE

Room Setup/Patient Positioning

The patient is placed prone on a Jackson table (Figure 2, A), and all bony prominences are padded well. The face and head are suspended in a padded holder, which allows clear visualization of the eyes, nose, and endotracheal tube. The knees are flexed, and the legs are padded with memory foam pillows. Once the patient is positioned, the table is brought into the jackknife position (Figure 2, B). This reduces the lumbar lordosis and facilitates exposure of the disk by increasing the interlaminar distance. The C-arm is then brought into the lateral position (Figure 2, C) and is draped out of the

sterile field once the skin is prepared. Figure 3 shows the placement of the operating room equipment and personnel.

FIGURE 1 T2-weighted MRIs of a 21-year-old athlete who presented with left S1 radiculopathy. A, Sagittal image demonstrates an L5/S1 disk herniation. B, Axial image demonstrates the left paramedian location (arrow).

FIGURE 2 Photographs demonstrate patient positioning and setup for lumbar microdiskectomy. A, The patient is positioned prone on the Jackson table, with all bony prominences well padded. B, The patient is positioned prone, with the Jackson table in the jackknife position to increase interlaminar distance. C, The C-arm in position for lateral imaging of the lumbar spine.

Special Instruments/Equipment/Implants

The tools needed to successfully perform a lumbar diskectomy include a C-arm fluoroscope, an operating microscope, and an adjustable Jackson table.

Surgical Technique for Lumbar Microdiskectomy

Preparation

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