19 Epiduroscopic Procedure Using the 1,414-nm Nd:YAG Laser (Lutronic Laser) Laser spine surgery has been in use for the treatment of spinal diseases since the 1980s. Laser therapy in spinal diseases is mostly carried out using the percutaneous and endoscopic approach. In this method, skin incision, as well as damage to the muscles, blood vessels, and nerves around the spine, is minimized. It is also advantageous as operations are done under local anesthesia and the satisfaction of patients is high owing to the short operation time. In February 1986, Choy et al1 implemented percutaneous laser disk decompression (PLDD) on a lumbar herniated disk. Since then, the development of laser therapy for spinal diseases has focused on lumbar disk disease, and PLDD became an active treatment following U.S. Food and Drug Administration (FDA) approval in 1991.2 Also, its application range has been expanding in recent times to include treatment of lumbar spinal stenosis and endoscopic treatment of ruptured cervical disk.3,4 Lasers have been used in medicine since the early 1960s. There are several types of lasers in use for the lumbar spine, with the most common being the holmium:yttrium-aluminum-garnet (Ho:YAG) and neodymium:YAG (Nd:YAG) lasers.5 The Ho:YAG laser (2,090 nm), owing to its close approximation to the intense 2-μm absorption band of water, appears to be a viable candidate for clinical trials of laser diskectomy.6 Also, the Ho: YAG laser is a pulsed laser, in contrast to the continuous-wave near-infrared lasers, and therefore has the advantage of producing minimal amounts of heat in adjacent tissues. From the standpoint of spinal surgery, Choy et al,1 in 1987, reported the first results of the Nd:YAG in laser-assisted disk decompression, yielding initial resolution of sciatica in 9 out of 12 patients. It is postulated that due to vaporization of water, internal disk pressure decreases, which, in turn, results in disc decompression as well as decompression of neighboring neural elements. Ongoing investigations of laser systems in the midinfrared range have led to more refined and appropriate optical wavelengths for use in the medical arena. Specific wavelengths applicable for use in the human intervertebral disk and currently approved by the FDA include potassium titanyl phosphate at 532 nm, Nd:YAG at 1,064 and 1,440 nm, CO2 at 10,600 nm, and Ho:YAG at 2,100 nm wavelength. With the exception of the CO2 laser, each of these laser systems can be delivered via flexible fiberoptics, making them suitable for use in the intervertebral disk. Currently, Ho:YAG is the most commonly used laser for ablation therapy. The Ho:YAG laser has been accepted as the safest laser because of low tissue penetration. The Nd:YAG laser, which was introduced before the Ho:YAG laser, was not used for deep tissue penetration. However, the Nd:YAG laser can also provide shallow tissue penetration by adjusting its wavelength to that of the Ho:YAG laser.7 The advantages of the Nd:YAG include easier laser control, a smaller manufacturing fee, and equivocal effectiveness.8,9 Moon et al10 reported that the 1,414-nm Nd:YAG laser is effective and safe for decompressing herniated intervertebral disks under the guidance of a spinal epiduroscope in vivo porcine models and in human cadaveric models. Lee and Kang11 introduced the percutaneous endoscopic laser annuloplasty (PELA) procedure, which cauterizes the granulation tissue related to the damaged annulus fibrosus. The main advantage of the PELA procedure is to preserve a healthy nucleus pulposus by minimizing damage to the center and front of the disk. They reported significant improvement of lumbago and statistically significant improvements in line with Macnab’s criteria following the PELA treatment. However, according to Carragee et al,12 only approximately 30% showed improvement. The frequency of specific complications or infection was not high. It is likely that damage to other parts was minimized by the short treatment time and use of the endoscope. Epiduroscopic laser neural decompression (ELND) is conducted using an extradural endoscope. For most patients, a nerve root block or palliative surgery is conducted. However, if these measures fail and there is no improvement after surgery, ELND is considered. It allows communication between a doctor and a patient under local anesthesia and exfoliation of adhesion in the epidural area. ELND also removes damaged tissue and inflammation and a protruded disk to lessen pressure on the nerves. Additionally, steroids and a topical anesthetic can be injected directly around a lesion. Hence, ELND can be a good therapy method for patients with various lesions. Jo et al13 implemented ELND using Ho:YAG lasers. In their procedure, a 2,100-nm wavelength was selected for the tissue to be removed. The laser was then inserted at a depth of 0.3 to 0.5 mm and the tissue was cauterized, thus minimizing damage to the surrounding tissue. However, since there are cases where the nerve roots are damaged or diskitis occurs, caution is required for this procedure. Transforaminal epiduroscopic laser annuloplasty (TELA) has been recently introduced and considered as a new method for the treatment of not only herniated lumbar disk, spinal stenosis, and postlumbar surgery syndrome but also chronic refractory low back pain, which is not well responded by other interventional treatments. It is a minimal invasive procedure for spine pain using epiduroscope and laser. For laser irradiation, an Nd: YAG laser (Lutronic) with a wavelength of 1,414 nm operating in the 200 to 600 mJ range was used (
19.1 Introduction
19.2 The Types of Laser and Their Respective Advantages
19.3 Percutaneous Endoscopic Laser Annuloplasty
19.4 Epiduroscopic Laser Neural Decompression
19.5 Transforaminal Epiduroscopic Laser Annuloplasty
Fig. 19.1).
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