Chapter 33: Hydrosurgery of Disc

INDICATIONS

Hydrodiscectomy is a form of disc decompression within the realm of minimally invasive discectomy that is an effective, predictable method of nucleus removal in disc pathology such as contained disc herniation or disc budge. Though the gold standard for surgical treatment of herniated disc disease is open micro­discectomy, minimally invasive treatments like hydrodiscectomy has gained momentum as an alternative treatment option. As with other forms of disc decompression, the primary goal is to remove herniated disc material to relieve compression of a nerve root or other neural structures. Patients requiring this procedure often have nerve impingement causing radicular pain symptoms that have not been relieved with conservative treatment over a 2 months span or epidural steroid injections. Hydrodiscectomy is an effective and predictable method of nucleus removal, removing hydrated or desiccated nucleus pulposus, and poses no risk for thermal damage. Its blunt tip design minimizes risk of end plate and annular damage. This means there is maximum safety within the disc.

The indications for hydrosurgery based on anatomical location of pain include:

• Unilateral leg pain greater than back pain

• Radicular symptoms in a dermatomal distribution correlated with MRI findings

• Positive straight leg raise test

• No improvement after 2 months of conservative treatment

• MRI evidence of contained disc protrusion/herniation

• Failed selective nerve root block ×1

• Discography positive for concordant pain

• Well-maintained disc height more than 50%

THE CONTRAINDICATIONS FOR HYDROSURGERY

As with any intervention, one must weigh the potential benefits to the potential complications. The following are contraindications for hydrosurgery.

• Radiologic evidence of severe lateral recess stenosis

• Radiologic evidence of calcified disc herniations

• Radiologic evidence of severe degenerative facet disease or osteophytic impingement on nerve roots

• Radiologic evidence of marked ligamentum flavum hypertrophy causing spinal stenosis

• Radiologic evidence of free or extruded disc fragments within the spinal canal (extending cephalad or caudad)

• Clinical evidence of significant progressive neurologic deficits or cauda equine syndrome

• Pathologies or conditions, such as fracture, tumor, pregnancy, or active infection that would put patient at risk

• Disc height less than 50%

• A disc herniation that takes up more than 50% of spinal canal

• Previous surgery with scar tissue nerve root entrapment

• Bony spinal stenosis

• Active infection

• Coagulopathy

• Grade V annular tear on discography

• Lumbosacral instability on flexion/extension studies or spondylolisthesis on MRI

• Radiologic evidence of a diffuse annular bulge extending from the entire circumference of vertebral body

• Significant end plate changes see on MRI

RELEVANT ANATOMY

The human body normally has 5 lumbar vertebrae separated by intervertebral discs. These discs act as a shock absorber to resist compressive forces generated on the vertebral segment above and below. The disc also provides height and widens the neuroforaminal space for a nerve root to exit the spinal column. Each disc is composed of a core of fibrous material in a mucoproteinaceous gel called the nucleus ...