Technique PLDD

 

Technique Percutaneous Laser Disc Decompression

SURGICAL TECHNIQUE

This procedure was performed in the prone position on a radiolucent humpbacked table under intravenous Fentanyl analgesia (Aware State Analgesia). A dose of 1.5 g. of intravenous Cefuroxime was routinely used for prophylaxis against infection. A designated nurse would record the distribution and reproduction of pain while the surgeon carried out SP & D.

The posterolateral approach was used to gain access to the intervertebral disc. A special jig was used to facilitate the selection of the entry portal (see X-ray Guidance Jig application Technique). The skin, subcutaneous tissue and paravertebral muscles were anaesthetised with 10 ml of 0.25% Lignocaine. Under two-dimensional fluoroscopy, a blunt, 2 mm probe was guided towards the posterolateral corner of the intervertebral disc. The probe was positioned in line with the posterior disc margins in the lateral projection and in the mid pedicular line on the postero anterior projection. A 22-gauge needle was then introduced into the disc. Discography was performed to evaluate disc containment, configuration of the degeneration within the disc, disc wall protrusion and the acceptance volume. Concordant symptom reproduction during SP & D was recorded and used to select the index level for intervention (SP & D Technique).

Once a degenerate, prolapsed and contained segment was identified with reproduction of the presenting symptoms, it was injected with 0.5 ml of indigo carmine used as an external chromophore to augment absorption of the KTP532 wavelength (Hijikata 1989, Jacques 1992).

Figure 19 Spinestat® Side fire Laserscope Probe

Using the discography needle as a guide, the cannula was advanced on to the disc wall. A trephine was passed down the cannula and the disc wall opened. The laser probe containing a 400μm optical fibre and suction sheath was inserted in to the disc. The position of the laser tip was confirmed in the antero posterior and lateral plane with the image intensifier. Laser energy was then delivered through the fibre and deflected laterally by 70° (Spinestat® system, Laserscope Inc, San Jose, California, USA). A standard energy dose of 1250 Joules delivered at 20 W of laser energy in pulses of 0.2 seconds for every 0.5 seconds with two Bar suction. If the patient perceived local heat, lasing was briefly discontinued and resumed once discomfort had subsided. The laser beam was directed towards the site of disc protrusion and away from the vertebral body endplates. The beam was directed particularly in to areas with a high fluid content, determined by an audible increase in vaporisation and aspiration. The beam was rotated to apply the energy in the antero-posterior axis of the disc. The probe was plied across the breadth of the disc through a traverse of 2.0 cm. Typical procedure times for a two level discography and single level KTP532 LDD was 30 - 45 minutes. The vaporisation depth was up to 4.5 mm with lateral thermal damage of 400 - 1200µm

Post-operative Regimen

Patients were discharged from hospital on same day or the morning following the procedure. All patients underwent a programme of graduated self-help muscle balancing physiotherapy 24 to 48 hours after surgery. Patients in sedentary work were allowed to return to work 5 21 days following surgery and those involved in physically demanding occupations after 6 12 weeks on a graduated guarded basis.