LS III-3
Percutaneous Techniques for Treating Disc Disease
Marco Leonardi, M.D.
Servizio di Neuroradiologia, Ospedale Bellaria, Bologna, Italy.
Introduction
The percutaneous approach to disc diseases was proposed many years ago and several different
techniques have been applied. Some are more “surgical”, like the Caspar technique based on the
insertion of thick tubes, even bilaterally, to allow mechanical rupture and removal of nucleus
fragments. Other methods may be considered more “mildly-invasive” and “radiological”, such as
chemonucleolysis with chymopapain or mechanical fragmentation by means of thin probes and
suction of nuclear fragments, such as the Onik procedures. More recently, technological advances
have led to the use of an oxygen-ozone mixture to obtain chemical lysis of the nucleus or
mechanical fragmentation with thinner probes. This presentation describes the different uses of
these modalities which are based on the percutaneous approach to the disc and the basic diagnostic
information supplied by discography. In fact, discography underlies all of these techniques given
the need to check the exact position of the needle and the exact size and position of the herniated
nucleus: percutaneous techniques are effective when the herniated part is connected with the centre
of the nucleus which is the sole possible percutaneous target. The percutaneous techniques have no
possibility of reaching the herniated part, their effect is on the nucleus and will be effective on the
herniations if there is a continuity which will “transfer” the therapeutic effects to the herniated
fragment.
Chemonucleolysis
Chemonucleolysis exploits the enzymatic activity of papain, which acts on the proteoglycans,
breaking up their protein “core” with a consequent reduction of the water content of the nucleus
pulposus.
Chymopapain may give rise to allergic and anaphylactic reactions as well as a toxic enzymatic
action on the arachnoid capillaries (if injected intrathecally). For this reason, chemonucleolysis
must be performed under discographic guidance.
Chemonucleolysis with papain is widely used in France. In Italy we have performed more than two
thousand procedures with good results in 83% of cases. One patient presented a vertebral body
discitis which resolved in three months with drug management.
Onik’s Automated Discectomy
This method is based on the use of a probe under vacuum which automatically aspirates and
fragments disc material which is collected in a bottle together with the flushing saline solution. Like
chemonucleolysis, it is performed under discographic guidance.
Automated discectomy is indicated in smaller herniations than those treated by chemonucleolysis.
In our experience, treating about 400 patients, it was successful in 75% of cases.
Oxygen-Ozone Therapy
This technique is described in more detail, because it is the newest procedure with few literature
reports available. At disc level, the mechanism of oxygen-ozone action is the oxidation of
proteoglycans with rupture of the sulphydryl bonds and a reduction of hydrophilic capacity, similar
to that of chymopapain, but more attenuated with a significant decrease in pain after treatment. At
root level, the mechanism of action is generically described as anti-inflammatory.
From December 1997 to August 2000 we treated 444 patients, 240 men and 204 women,
administering 723 treatments at disc levels L4-L5 and L5-S1 in 85% of cases. Two levels were
treated in 160 patients and three levels in eight. Repeat treatments involved the same level in 100
patients and a different level in 25. We describe 191 patients who underwent treatment at a single
sitting with a follow-up visit six months later. All patients had a four to six month history of
intractable back and leg pain despite conservative measures without neurological deficit. All
patients underwent CT and/or MR scan with a diagnosis of disc herniation at one or more levels.
Patients with neurological deficit or neurological features suggesting migrated herniated fragment
were excluded.
Treatment consisted in intervertebral disc puncture in fluoroscopy (G22 needle) followed by
discography to confirm correct needle placement and ascertain the morphology of the herniation (to
rule out herniated fragments) and the degree of disc degeneration. A 27 mcmg/ml ozone mixture
was injected 4ml into the disc and 8ml into the perivertebral and periradicular soft parts. Patients
were then assessed after 7-10 days, one month and six months. Treatment was successful in 126
cases, with no change in symptoms in 56 and a worsening of symptoms in nine. One of the latter
presented mild spondilo-discitis treated conservatively with success; the other eight probably
deteriorated because of disease progression.
As a whole, excellent-good results were achieved in 66% of cases, a lower percentage than that of
enzymatic chemonucleolysis. This is an important parameter since comparison with
chemonucleolysis is best suited to ascertain the advantages of ozone therapy given the similar
degree of invasiveness. However, ozone treatment is even less invasive than chemonucleolysis: a
narrower gauge needle is used and the period of discomfort following treatment and bed rest is
reduced to two or three days instead of one to two weeks; no hospital stay is necessary thereby
making the cost of ozone therapy ten times lower. Repeat treatments will enhance results and are
usually suggested by patients satisfied with the previous outcome and keen to repeat the treatment
for a recurrence or to enhance results giving a significant but incomplete improvement of
symptoms.
Manual Percutaneous Discectomy
Based on the use of probes, similar to Onik’s introductory system, and special mini-forceps for the
mechanical removal of the nucleus pulposus this technique has been implemented in few cases and
no conclusions can yet be drawn on its effectiveness.
Treatment of Failures
Most patients who fail to benefit from percutaneous treatments are referred for surgery without any
negative effects. Our series included two patients who underwent surgery soon after oxygen-ozone
therapy. They presented severe disc degeneration, probably the result of nucleolysis with ozone
which will be the topic of a separate report.
Conclusions
Papain and Onik were widely used about ten years ago, results were satisfactory in selected cases,
but several problems arose. In fact, papain (chymodiactin) obtained FDA authorisation in 1982, but
never received EU approval, which is a major drawback in Europe, especially nowadays with the
increasingly high risk of litigation in the case of failure or complication. In our experience, the Onik
procedure is indicated for small herniations, and the ratio between cost-invasiveness and pathology
definitely favours a more conservative approach or a less invasive procedure.
Intradiscal ozone therapy is successful in a slightly lower percentage of patients than those treated
by chemonucleolysis, but it is well tolerated even in elderly patients. The burning sensation
experienced on paraspinal and periradicular injection of the ozone is temporary. The slight
reduction in the percentage of positive results compared with chemonucleolysis becomes negligible
in the context of a wider cost-benefit assessment.
The percutaneous approach allows the treatment of disc herniation with a satisfactory level of good
results, average 70%, in selected cases, with small or medium size herniations with continuity
between the central nucleus and the herniated fragment.
Note
More and more frequently we find disc pathology associated with vertebral spine instability,
especially in elderly people or in post surgical cases. The diagnosis of vertebral instability is crucial
and will radically affect the therapeutic approach (cage stabilisation, etc.). From August 1999 to
date, our neuroradiology unit has investigated vertebral instability by loaded lumbosacral spine CT
scans (AL-CT) using a custom-made axial compressor. CT study aims to disclose vertebral
instability and/or significant changes to disc morphology by simulating the movement from sitting
to standing by applying a load equal to 65% of the patient’s body weight.
The examination includes two CT acquisitions of the lumbosacral spine from L3 to S1 at rest and
after application of the axial load followed by multiplanar and 4D-Angio reconstructions and a cine
comparison of the reformatted images with and without axial-loading (Kodak PACS Workstation).
This type of CT examination is essential in doubtful cases to avoid inappropriate treatment of
simple disc herniations.
Acknowledgements: I wish to express my gratitute to my coworkers, Giuliano Fabris,
Antonino Lavaroni, Carlotta Barbara, Luigi Simonetti and Silvia Giatti, whose help has
proved invaluable.
Prof. Marco Leonardi
Servizio di Neuroradiologia
Ospedale Bellaria
Via Altura 3
40139 Bologna, Italy
Tel.: +39.051.6225520
Fax: +39.051.6225785
E mail: marco.leonardi@ausl.bologna.it
References
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Captions
Figure 1 AP and lateral view: the correct positioning of the needle at the centre of the disc is very
important.
Figure 2 Discography L4-L5: good position of the needle. Diffuse degeneration of the nucleus with
posterior herniation.
Figure 3 CT-Discography L4-L5, after oxygen-ozone injection: lateral right hernia. Little gas
bubbles are recognisable around the nerve root and on the lateral margin of the herniated disc.
Figure 4 CT-Discography L4-L5, after oxygen-ozone injection: large median disc herniation. Gas
bubbles are recognisable in the hernia, around the nerve roots and in the paraspinal muscles.
Figure 5 CT-Discography L5-S1, after oxygen-ozone injection: large discal hernia, paramedian,
left. Gas bubble in the herniated disc.