Percutaneous Laser Disc Decompression
Backpain
Back pain is rated to be the No.1 ailment in Europe. 90% of all Germans will complain about back pain in the course of their life. Disc protrusions and prolapses can be the cause for nerve root irritations in the cervical or lumbar spine. For the afflicted, this causes a substantial limitation to their range of motion and mobility.
Treatment of back pain
Modern treatment strategies are based on the concept of multi-modal development of back pain. This is the basis for an individual treatment with the goal of a pain free life for the patient and functional rehabilitation.
The framework of conservative treatment is physical therapy, physiotherapy and pain medication at the end of which image-guided infiltrations or minimally invasive procedures are an option. Apart from standard fluoroscopy and CT-guidance, MR-guided infiltrations of the spinal nerves, the facet joints, the sacroiliac joints and the sympathetic trunk are clinically effective and enable ionization-free and precise image guidance.
Open High-Field MRI
As of the beginning of 2007, the Charité has an open high-field MRI available (see image). The advantages of this system over the conventional tunnel system MRI are the good access to the patient and the precise image quality which is comparable to that generated in a closed configuration system.
Lasertherapy of the lumbar disc
Back pain is a major cost factor in the health system and poses a major burden on the patients way of life. More often than not, the pain can put a strain on the work and personal life of the patient (Meaning of Back Pain). Should conservative treatment (including spinal infiltration therapy) of these disc diseases fail over the course of more than 6 weeks, some patients may benefit from a minimally invasive LASER procedure, beforeopen surgery becomes inevitable.
Indications:
- Back pain caused by lumbar disc prolapse, degeneration or protrusion.
- Failiure of conservative treatment for at least 6 weeks
Advantages:
- Gentle and minimally invasive treatment method.
- Local anaesthesia. No general anaesthesia with the associated risks.
- No risk of scarring at the intervention site.
- Only short hospital stays are required.
- Repeat PLDD is possible, especially when considering that MRI is free of ionizing radiation.
- General advantages of MR-image guidance.
- Use of so-called MR-thermometry: heating effects of the LASER can be monitored online.
- This can increase patient safety and ensure a positive theapeutic outcome.
Typically PLDD (Percutaneous Laser Disc Decompression) is performed under x-ray or CT-guidance and has been established under these imaging modalities as a safe and effective treatment modality in the therapy of vertebral disc protrusions. Research and developement at the Charité have established PLDD unter open MRI guidance with the goal of using MR-guided PLDD in clinical routine.
Percutaneous Laser Disc Decompression (PLDD) in the open high field MRI
This procedure is based on the effects of a 1064nm Neodymium YAG LASER on the vertebral disc. Under local anaesthesia, a 0.2mm laser bare fiber is inserted through a thin puncture needle into center of the prolapsed disc. The exact needl position is continuously monitored by the physician with interactive MRI.
Image of a patient in lateral recub position during PLDD.
Positive Laser Effects
In the center of the prolapsed disc, the laser creates vaporisation effects (blue arrows) and causes the saught for drop in pressure within the disc.
Graphic depiction of PLDD: Left: Disc protrusion herniating a spinal nerve. Center: Laser application. Right: Retracted Disc Protrusion after PLDD and reduction of pressure on the spinal nerve. a Spinal Chord. b Disc Protrusion. c Spinal nerve. d Fibrous Annulus. e Nucleus Pulposus. f Laser Fiber. g Puncture Cannula. h Gas in the Protrusion. k Cavum created by LASER application.
Moreover, the LASER induces a shrinking process within the disc tissue: i.e.induced by heat, the collagen structure of the fibrous annulus shrinks at it’s outer regions, while the nucleus remains unharmed. This is the main difference between PLDD and other minimally invasive methods, with respect to therapeutic success. The spinal nerve is decompressed while the prolapsed tissue is retracted by the shrinking process and the pain is alleviated. What is more, pain receptors within the degenerated disc are also ablated and thus further irritation is prevented. The fibrous annulus’ tissue is further stabilized by the the Lasing process and small tears are closed. This also prevents new pain receptors from growing back into the degenerated disc. The general stability of the disc is reinforced during this procedure, while open spinal surgery decreases the disc’s stability.
The LASER enables presice coagulation and evaporization of discal tissue. MRI offers excellent differentiability and identification of the anatomic structures, such as vertebral disc, vertebral body, spinal nerves and spinal chord. This further enables the specific sparing of sensitive structures during the LASER procedure.
Case – 42year old patient with low back pain and radiation into the left leg and sole of the foot (so-called “radicular” pain) with a known disc protrusion at L5/S1. The pain was not responding to conservative therapy for more than 4 months. Immediately after PLDD, the patient reported on substantial improvement of his symptoms. Left: T1-w FSE sequence in transverse section. Right: Corresponding sagittal image. Intraoperative MRI with depiction of the PLDD needle within the disc.
With open high-field MRI (1.0 T Panorama HFO, Philips Healthcare, NL) the Charité can now offer an MRI system which allows ideal access to the patient during interventions, thanks to it’s horizontally open design. The puncture process can be monitored with fast and precise imaging sequences and needle positioning can be controlled with interactive, near real-time sequences (so-called MR-fluoroscopy). The option for multi-planar imaging allows the interventionalist to monitor anatomy, pathology and surgery from many angles throughout the procedure. With the new option of monitoring the LASER application with temperature calaculation from MRI data, PLDD can be made even more safe under MR-monitoring.
PLDD under open MRI control is defined by it’s low rate of complications. Due to it’s minimally invasive character, the procedure can be performed under local anaesthesia. And finally, PLDD only requires very short hospitalization periods (24-48h post PLDD).
Florian Streitparth
Thula Walter (Trans.)
Felix Güttler (Ed.)
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