A biophysical explanation for Nd:YAG percutaneous laser disc decompression success

Ultrasound-Guided percutaneous laser disc decompression (PLDD) with fluoroscopic validation for the treatment of cervical disc herniation: Technical note

OBJECTIVE

Percutaneous laser disc decompression (PLDD) has been regarded as an effective alternative for the treatment of cervical soft disc herniations. Repeated X-Ray scanning is essential when performing this technique.

DESIGN

Technical note.

METHODS

We present a new method for the treatment of cervical disc herniation using ultrasound to guide the needle entry to the cervical disc, to avoid excess of radiation exposure during the surgical procedure. We evaluated the efficacy of this cervical approach.We retrospectively reviewed the clinical data of 14 cases who underwent a PLDD under ultrasound (US) guidance for the treatment of contained cervical disc herniation using a 1470 Nm diode laser. The lower cervical discs (C5-C6 and C6-C7) were the most affected sites, accounting for 78.6% of surgical discs.A significant NRS reduction between baseline and 1 month (p = 0.0002) and between baseline and 12 months (p = 0.0007) was observed.

CONCLUSIONS

Our results support the conclusion that US guided PLDD with fluoroscopic validation is a minimally invasive technique for patients affected by herniated cervical discs, but proper choice of patients is critical. This approach should not be performed except after adequate training under close supervision of surgeons experienced in this procedure and in interventional US.

Patient selection criteria for percutaneous anterior cervical laser versus endoscopic discectomy

BACKGROUND

Percutaneous anterior laser and anterior endoscopic cervical spine surgery are associated with less approach trauma than conventional open cervical spine surgery. The literature illustrating their appropriate use corroborated with objective outcome evidence is scarce. The authors were interested in comparing the clinical outcomes following percutaneous laser disc decompression (PLDD) versus percutaneous endoscopic disc decompression (PEDD). © 2021 Wiley Periodicals LLC.

MATERIALS AND METHODS

Thirty patients with soft contained symptomatic cervical disc herniations and an average age of 50.5 years (range 26 - 68 years; 16 males and 14 females) were prospectively enrolled in 2 groups of 15 patients to be either treated with PLDD or PEDD. All patients underwent PLDD or PEDD under local anesthesia and sedation. Clinical outcomes were assessed with the Macnab criteria VAS score for arm pain. Complications and reoperations were recorded.

RESULTS

There were significant reductions in the VAS score for arm pain from preoperative 8.4 ± 2.5 to 3.1 ± 1.2 in the PLDD group (P < 0.03), and from preoperative 8.6 ± 2.7 to 2.4 ± 1.1 (P < 0.01) in the PEDD group. In the PLDD group, Macnab outcomes were excellent in 21% of patients, good in 44%, fair in 21%, and poor in 14%. In the PEDD group, Macnab outcomes were excellent in 14% of patients, good in 32%, fair in 12%, and poor in the remaining 12%. There were no statistically significant differences in clinical outcomes between the PLDD and the PEDD group. There were no approach-related or surgical complications.

CONCLUSIONS

Tissue trauma is significantly reduced with laser and endoscopic surgery techniques. PLDD and PEDD are both suitable for the specific indication of soft, symptomatic contained cervical disc herniations. The authors' small prospective cohort study indicates that PLDD and PEDD are options for cervical decompression surgery when medical comorbidities or preferences by patients and surgeons dictate more minimally invasive strategies.

Intradiscal Microprobe With a Vibrational Optical Fiber for Diagnosis and Thermal Therapy of Discogenic Pain Due to an Annular Fissure

Major studies have shown that discogenic pain is the most common cause of chronic lower back pain, accounting for 40% of all the causes. Provocation discography—inducing pains by pressing nerve structures around the annular fissures—is recognized as the only method for diagnosing discogenic pain. However, the method is not available to the patient with full-thickness fissures because of a contrast media leakage through the fissure. In this paper, intradiscal microprobes (IDMPs) affecting direct mechanical stimulus on the nerve fiber are presented for diagnosis of the fissure. The plastic optical fiber (POF), located in the flexible polymer tube, can be navigated to fissure vicinities. Then, a linear or rotational motor placed inside the probe grip generates a minute axial or radial vibration of the fiber tip, which irritates the tiny pain nerve fiber around the fissure. The intensity of the pain can serve as a guideline to determine the level of discogenic disease. The frequency and amplitude of the axial (radial) vibration discography were 2.9–5.7 (4.0–7.0) Hz and 1.5–3.4 (0.06–3.25) mm, respectively. Furthermore, the optical experiments for evaluation of thermal therapy application were successfully confirmed.

A quantitative study of intervertebral disc morphologic changes following plasma-mediated percutaneous discectomy

OBJECTIVE

To quantitatively evaluate interval magnetic resonance imaging (MRI) changes in disc morphology following plasma-mediated percutaneous discectomy.

DESIGN/SETTING

A retrospective comparison of pretreatment and posttreatment MRIs at a single university spine clinic.

SUBJECTS

From a group of 60 consecutively treated patients, 15 met the study inclusion and exclusion criteria. All had either failed treatment or had other clinical reasons for a posttreatment MRI.

METHODS

Two independent physicians electronically measured disc protrusion size and disc height at the treatment discs and adjacent discs on pre- and posttreatment MRI scans. Additionally, images were compared for gross anatomic changes including disc degeneration by Pfirrman classification, new disc herniations, high intensity zone (HIZ), vertebral endplate changes, post-contrast enhancement, and changes in segmental alignment. Pearson r correlation was used to determine interobserver reliability between the two physicians' MRI measurements. Paired t-tests were calculated for comparisons of pre- and posttreatment MRI measurements, and an ANOVA was performed for comparison of pre- to posttreatment changes in disc height measurements at treatment levels relative to adjacent levels.

RESULTS

Correlation was high for measurement of disc height change (r = 0.89; P < 0.0001) and good for anteroposterior protrusion size change (r = 0.51; P = 0.0512). Disc height at treated discs demonstrated a small but statistically significant mean interval reduction of 0.48 mm (P = 0.0018). This remained significant when compared with the adjacent control discs (P < 0.0001). Pretreatment mean disc protrusion size (4.74 mm; range 3.75-6.55 mm) did not differ significantly (P = 0.1145) from posttreatment protrusion size (4.42 mm; range 2.55-7.95 mm). Gross anatomic changes at treatment levels included reduced disc protrusion size (N = 6), enlarged protrusion (N = 3), resolution of HIZ (N = 3), and improvement in endplate signal changes (N = 1). Also, 11/15 posttreatment MRIs included post-contrast images that showed epidural fibrosis (N = 1), rim enhancement (N = 2), and enhancement of the posterior annulus (N = 4).

CONCLUSIONS

Based on MRI examinations, subtle anatomic changes may occur following plasma-mediated percutaneous discectomy. Further study is required to determine the clinical relevance of these changes.

Mid-term efficacy of percutaneous laser disc decompression for treatment of cervical vertigo

OBJECTIVE

To observe and analyze the mid-term efficacy of percutaneous laser disc decompression (PLDD) for the treatment of cervical vertigo.

METHODS

Thirty-five patients with cervical vertigo were admitted from September 2002 to December 2006, including 14 males and 21 females, aged between 35 and 79 years with an average of 59.1 years. All patients were treated with PLDD by the Nd:YAG laser therapy (wavelength: 1,064 nm) and were followed up. The improvement of vertigo and associated symptoms was evaluated by numerical rating scale (NRS) assessment, while fineness rate and efficient rate were evaluated using modified MacNab assessment criteria.

RESULTS

No intraoperative and postoperative complication was reported. The patients were followed up for 24-66 months. At the end of the follow-up, the average NRS scores of the dizziness and complications are significantly smaller. The overall efficacy was evaluated based on modified MacNab criteria: excellent, 18 cases; good, 7 cases; acceptable, 5 cases; and poor, 5 cases. No statistical difference existed between age groups (P > 0.05) and also between gender groups (P > 0.05).

CONCLUSION

PLDD treatment of cervical vertigo trauma has many advantages, such as minimal trauma, high safety, and satisfactory mid-term efficacy with no significant difference in clinical efficacy between different age and gender groups.

Disc volume reduction with percutaneous nucleoplasty in an animal model

Study Design

We assessed volume following nucleoplasty disc decompression in lower lumbar spines from cadaveric pigs using 7.1Tesla magnetic resonance imaging (MRI).

Purpose

To investigate coblation-induced volume reductions as a possible mechanism underlying nucleoplasty.

Methods

We assessed volume following nucleoplastic disc decompression in pig spines using 7.1-Tesla MRI. Volumetry was performed in lumbar discs of 21 postmortem pigs. A preoperative image data set was obtained, volume was determined, and either disc decompression or placebo therapy was performed in a randomized manner. Group 1 (nucleoplasty group) was treated according to the usual nucleoplasty protocol with coblation current applied to 6 channels for 10 seconds each in an application field of 360°; in group 2 (placebo group) the same procedure was performed but without coblation current. After the procedure, a second data set was generated and volumes calculated and matched with the preoperative measurements in a blinded manner. To analyze the effectiveness of nucleoplasty, volumes between treatment and placebo groups were compared.

Results

The average preoperative nucleus volume was 0.994 ml (SD: 0.298 ml). In the nucleoplasty group (n = 21) volume was reduced by an average of 0.087 ml (SD: 0.110 ml) or 7.14%. In the placebo group (n = 21) volume was increased by an average of 0.075 ml (SD: 0.075 ml) or 8.94%. The average nucleoplasty-induced volume reduction was 0.162 ml (SD: 0.124 ml) or 16.08%. Volume reduction in lumbar discs was significant in favor of the nucleoplasty group (p<0.0001).

Conclusions

Our study demonstrates that nucleoplasty has a volume-reducing effect on the lumbar nucleus pulposus in an animal model. Furthermore, we show the volume reduction to be a coblation effect of nucleoplasty in porcine discs.

Evidence-informed management of chronic low back pain with minimally invasive nuclear decompression

The management of chronic low back pain (CLBP) has proven very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.

[Efficacy of percutaneous laser disc decompression for radiculalgia due to lumbar disc hernia (149 patients)]

OBJECTIVE

To assess the efficacy of percutaneous laser disc decompression for patients with radicular pain due to lumbar disc hernia and to identify factors that may predict outcome.

METHODS

The study included all patients treated with percutaneous laser disc decompression from May 2003 through May 2005 at Reims University Hospital and the Courlancy Clinic of Reims. Each patient had previous undergone at least six weeks of conventional medical treatment. The same technique, with either a laser diode or Nd: YAG, was used under endoscopic control and with neuroleptanalgesia. They were seen at 1, 3, 6 and 12 months. The principal evaluation criteria were the course of radicular pain, return to work, and need for surgery.

RESULTS

We reexamined 149 patients 1 month after the procedure, 135 after 3 months, 102 after 6 months and 59 a year after the procedure. At a month after surgery, radicular pain had decreased by at least half, and sometimes even completely disappeared in 63.1% of patients at 1 month, 66.6% at 3 months, 73.5% at 6 months, and 83.1% at 12 months, while 24%, 50,4%, 61.2%, and 67.3%, respectively, had returned to work. No patient had serious complications. Finally, 45 of the 149 (30.2%) patients chose to have a traditional surgical procedure after percutaneous laser disc decompression.

CONCLUSION

Percutaneous laser disc decompression is effective, noninvasive and well tolerated for patients with radicular pain due to lumbar disc hernia.

Risk evaluation of thermal injury to the cervical spine during intradiscal laser application in vitro

OBJECTIVE

We aimed to investigate temperature distribution during laser and its possible thermal damage to the neurovascular structures.

BACKGROUND DATA

Percutaneous laser disc decompression (PLDD) is now being performed as a minimally invasive intradiscal technique for the operative therapy of non-sequestered herniated cervical discs. As yet, no experimental basic research has been reported with regard to temperature rise and distribution in the cervical region during laser radiation.

MATERIALS AND METHODS

An in vitro laser procedure was performed on human cervical intervertebral discs under standardized conditions. A thermo-camera was used to monitor in real-time the zones sensitive to temperature increase.

RESULTS

Average intervertebral disc volume was 2000 mm3. With a total energy conduction of 600 Joules, a temperature increase of around 30 degrees C was shown with an initial temperature of 28 degrees C at the posterior longitudinal ligament lying immediately in front of the myelon. The defect volume was less than 1% of the total intervertebral disc volume.

CONCLUSION

If, during laser application, the total amount of conducted energy is too high, with an unfavorable position of the fibers in the intervertebral space, there is a risk of thermal damage to the spinal cord and nerve roots.

Evaluation of temperature distributions in cadaveric lumbar spine during nucleoplasty

In this study, temperature maps were obtained throughout human cadaveric disc specimens (n = 6) during a simulated Nucleoplasty treatment. The procedure was performed using the Perc-DL SpineWand (ArthroCare, Sunnyvale, CA) inserted through a 17 gage needle into the human cadaveric disc. The device uses a dual mode heating technique which employs a high voltage radio frequency (RF) plasma field to vaporize tissue (Coblation), followed by bipolar RF current heating for thermal coagulation. The device, with a distal 's-curve', is manipulated manually to create a series of six channels at a 60 degrees angular spacing within a period of 3 min. A computer-controlled, motorized translational system was used to reproducibly mimic the insertion (Coblation) and retraction (rf-coagulation) performed during clinical implementation, with rotation performed manually between each Coblation/coagulation cycle. Transient temperature data were obtained using five multi-junction thermocouple probes (5-8 junctions spaced at either 2 or 5 mm intervals, with 0.33 or 0.56 mm probe diameter) spaced throughout the desired heating volume. Transient temperature curves were obtained from 26+ points throughout the disc, and the data used to calculate accumulated thermal doses. Transient peaks of 80-90 degrees C were recorded within the discs, with temperatures greater than 60-65 degrees C measured within a radial distance of 3-4 mm from the introducer (applicator centreline). Accumulated thermal doses of t43 > 250 min were produced at radial distances of up to 6 mm from the introducer. Gross inspection of the discs revealed a narrow region of coagulation along the insertion length. Given these radial thermal penetrations and the possibility for unpredictable positioning during current clinical implementation, high temperatures and lethal thermal doses in small regions outside of the nucleus, or within the bone endplates, may be possible in clinical implementation.

Percutaneous Laser Disc Decompression: A 17-Year Experience

In this review, we analyze our effort to demonstrate the effectiveness of a new approach to the treatment of herniated disc disease using Nd:YAG laser energy introduced into a herniated disc under fluoroscopic control and local anesthesia. 2400 PLDD procedures (combined number of decompressions in cervical, thoracic, and lumbar discs were performed in the past 18(1/2) years in 1275 patients. The overall success rate according to the MacNab criteria was 89%. The complication rate (only infectious disciitis) was 0.4%; all 10 patients with complications were cured with appropriate antibiotics. The recurrence rate was 5%, and usually due to reinjury. There were no deaths, and no cases of nerve or cord damage. PLDD is a safe and effective outpatient procedure for the treatment of herniated disc disease with the advantages of relative non-invasiveness, usually immediate relief of back and sciatic pain, early return to work (generally 5-6 days), and a low complication and recurrence rate. It can also be repeated if necessary as many as five times.

Image-guided percutaneous laser disk decompression for herniated lumbar disks: a 4-year follow-up in 200 patients

OBJECTIVE

The purpose of this study was to describe the long-term effect of image-guided percutaneous laser disk decompression (PLDD).

BACKGROUND DATA

PLDD has been reported to be an alternative method to treat herniated lumbar disks. It has proved to be effective on a short-term basis. Although the procedure has been used for several years, few articles report on the long-term effect of the intervention.

MATERIALS AND METHODS

Two hundred patients, who were treated with image-guided PLDD for herniated lumbar disks, were observed over a period of 4 +/- 1.3 years. Treatments were carried out under CT/fluoroscopy guidance with local anesthesia on an outpatient basis with an Nd:YAG laser of 1064 nm.

RESULTS

At follow-up, back pain was eliminated or reduced in 73% of the patients. Regarding sensorimotor impairment, PLDD did have a positive effect on 74% of the patients. In the majority of patients, the number of sick days and consumption of pain medication was reduced. In one patient, diskitis occurred as a complication of PLDD; 74% of the patients said they were satisfied with the outcome of the therapy; and 81.5% of the patients would have required another PLDD in cases of disk herniation.

CONCLUSION

From our clinical results, we conclude that image-guided PLDD is an effective and secure method to treat contained herniated lumbar disks. Advantages of the procedure include the minimally invasive approach on an out-patient basis and the low complication rate.