Srdjan Mirkovic

1. Spinal stenosis

a. Failure to respond to nonoperative treatment with a predominance of lower extremity symptoms

b. Unremitting pain and marked limitations of daily activities

3. Precipitous neurologic deterioration

4. Cauda equina syndrome

1. Low back pain in the presence of multi-level degenerative disc disease

2. Lack of confirmatory imaging study

1. Medical and anesthetic clearance

2. Clear identification of the exact location of spinal stenosis

3. If possible, cessation of smoking

4. Fitness education and weight reduction

5. Radiographic imaging (MRI, CT myelogram) including sagittal foraminal reconstruction

1. Position the patient in a prone kneeling position on chest rolls with the abdomen hanging free. The kneeling position is contraindicated in the presence of knee or hip disease.

2. Use spinal or general anesthesia for short segment, decompressive laminectomy without instrumentation. Use general anesthesia for long segment decompression or instrumentation. Consider hypotensive anesthesia to diminish epidural bleeding if there are no medical contraindications.

3. Special instruments: 45-degree angled Kerrosen rongeurs ranging in size from 1 to 4 mm.

4. Luksell rongeurs are used to debulk lamina, facet joints, remove spinous processes, and decorticate.

5. Use 4-mm and 5-mm burrs to thin lamina and facet joints.

6. Penfield elevators are used to palpate nerve roots and dura, and dissect surgical planes.

7. Different sized ball-ended probes are used to evaluate foraminal decompression.

8. Microscope or loop magnification and light augmentation

9. Angled curettes are used to free-up scar tissue and develop surgical planes.

11. Bipolar coagulation

1. The interlaminar space may be completely obliterated in patients with severe spine degeneration. The superior aspect of the lamina can be difficult to identify due to severe shingling. Consider placing a laminar distractor between the spinous processes, thereby allowing distraction of the interlaminar space and delineation of the inferior border of the superior laminae, ligamentum flavum, and facet joints. This facilitates initiation of the laminectomy with kerrosens posterior to the ligamentum flavum. Once the ligamentum flavum plane is identified, the laminar spreaders can be removed and the spinous processes rongeured with a Luksell and removed with kerrosens. The laminectomy can then proceed in routine fashion.

2. The three common areas for significant nerve root compression are: the lateral recess secondary to facet joint hypertrophy; the central stenosis due to the hypertrophied ligamentum flavum; and the foraminal stenosis due to degenerative disc narrowing. Decompression of the superior aspect of the caudal lamina is facilitated by either partially or completely removing the spinous processes of the inferior vertebra. The underlying lamina is thick and should be thinned with a burr or with a rongeur.

3. In patients with one level spinal stenosis (e.g., the L4-L5 level), the inferior half of the lamina of L4 and the superior half of the lamina of L5 need to be removed.

4. Lateral recess stenosis due to dorsal compression from the overhanging hypertrophied facet is a common cause of surgical failure. Affected nerve roots need to be clearly decompressed with clear visualization of the medial aspect of the corresponding pedicle.

5. Check the foramina for impingement using ball-ended probes.

6. Consider concomitant spinal fusion in the presence of degenerative spondylolisthesis, scoliosis and/or kyphosis, greater than 50% excision of the facet bilaterally, as well as recurrent stenosis above a previous fusion.

7. If a kneeling position is used with a patient#39;s back in kyphosis, ensure that adequate foraminal decompression has been performed to avoid postoperative stenosis when the patient resumes standing in the lordotic position.

1. Avoid inadequate decompression.

2. If possible, avoid complete excision of the facet joints to minimize the incidence of postoperative instability.

3. Avoid dural tears. Minimize dural tears by carefully identifying the surgical planes (notably the plane between bone and ligamentum flavum, and between the ligamentum flavum and the epidural space). Cottonoids placed in the plane of dissection during laminectomy protect the dura and assist in hemostasis.

4. Avoid foregoing radiographs. Verify radiographi-cally that the decompression has extended the extent of the desired surgery.