Evaluation of different laser wavelengths on ablation lesion and residual thermal injury in intervertebral discs of the lumbar spine

Efficacy of Percutaneous Laser Disc Decompression (PLDD) Combined with an Oral Food Supplement for Lumbar Disc Herniation

Background: In recent years, minimally invasive treatment options for lumbar disc herniation, such as percutaneous laser disc decompression (PLDD), have been introduced to avoid more invasive surgical methods. Combining these minimally invasive approaches with nutraceuticals that are effective in neuroprotection and pain management may lead to better long-term outcomes. Methods: The present study evaluated the beneficial effects of a new oral food supplement composed of acetyl-L-carnitine, α-lipoic acid, quercetin, bromelain, pantothenic acid, and vitamins C, B1, B2, B6, and B12 in patients with neuropathic pain due to herniated lumbar discs treated with PLDD. Patients were divided into two groups of 26 patients each: group A underwent PLDD alone, while group B underwent PLDD followed by a dietary supplement for two months after surgery. Preoperative VAS scores for leg pain were recorded for both groups and no significant difference was observed (8.7 for Group A and 8.6 for Group B). Results: In Group A, the mean postoperative VAS score for leg pain at a 1-month follow-up was 2.5, which remained stable at 3 months. In Group B, the mean postoperative VAS score was 2.0 at 1-month and improved to 1.6 at the 3-month follow-up. According to self-reported leg pain assessments, 66.5% of the patients using the dietary supplement reported a significantly better pain condition, and 43.5% reported a somewhat better situation. In contrast, 7.7% of the patients who underwent PLDD alone reported no changes in leg pain at the final follow-up. Conclusions: The results of our study indicate that the oral food supplement could provide a safe and effective treatment in patients with painful radiculopathy, enhancing the recovery of sensory fiber function in lumbar nerve roots after surgical lumbar disc decompression.

An in vitro comparison of three nucleus pulposus removal techniques for partial intervertebral disc replacement: An ultra-high resolution MRI study

Background

Nuclectomy, also known as nucleotomy, is a percutaneous surgical procedure performed to remove nucleus material from the center of the disc. Multiple techniques have been considered to perform a nuclectomy, however, the advantages and disadvantages of each are not well understood.

Aims

This in vitro biomechanical investigation on human cadaveric specimens aimed to quantitatively compare three nuclectomy techniques performed using an automated shaver, rongeurs, and laser.

Material & Methods

Comparisons were made in terms of mass, volume and location of material removal, changes in disc height, and stiffness. Fifteen vertebra-disc-vertebra lumbar specimens were acquired from six donors (40 ± 13 years) and split into three groups. Before and after nucleotomy axial mechanical tests were performed and T2-weighted 9.4T MRIs were acquired for each specimen.

Results

When using the automated shaver and rongeurs similar volumes of disc material were removed (2.51 ± 1.10% and 2.76 ± 1.39% of the total disc volume, respectively), while considerably less material was removed using the laser (0.12 ± 0.07%). Nuclectomy using the automated shaver and rongeurs significantly reduced the toe-region stiffness (p = 0.036), while the reduction in the linear region stiffness was significant only for the rongeurs group (p = 0.011). Post-nuclectomy, 60% of the rongeurs group specimens showed changes in the endplate profile while 40% from the laser group showed subchondral marrow changes.

Discussion

From the MRIs, homogeneous cavities were seen in the center of the disc when using the automated shaver. When using rongeurs, material was removed non-homogeneously both from the nucleus and annulus regions. Laser ablation formed small and localized cavities suggesting that the technique is not suitable to remove large volumes of material unless it is developed and optimized for this application.

Conclusion

The results demonstrate that both rongeurs and automated shavers can be used to remove large volumes of NP material but the reduced risk of collateral damage to surrounding tissues suggests that the automated shaver may be more suitable.

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.

Local Effects of a 1940 nm Thulium-Doped Fiber Laser and a 1470 nm Diode Laser on the Pulmonary Parenchyma: An Experimental Study in a Pig Model

The lungs are a common site of metastases from malignant tumors. Their removal with a minimal but safe tissue margin is essential for the long-term survival of patients. The aim of this study was to evaluate the usefulness of a 1940 nm thulium-doped fiber laser (TDFL) and a 1470 nm diode laser (DL) in a pig model of lung surgery that involved the incision and excision of lung tissue. Histopathological analysis was performed on days 0 and 7 after surgery. Neither TDFL nor DL caused significant perioperative or postoperative bleeding. Histological analysis revealed the presence of carbonized necrotic tissue, mixed fibrin-cellular exudate in the superficial zone of thermal damage and bands of deeper thermal changes. The mean total width of thermal damage on day 0 was 499.46 ± 61.44 and 937.39 ± 109.65 µm for TDFL and DL, respectively. On day 7, cell activation and repair processes were visible. The total width of thermal damage was 2615.74 ± 487.17 µm for TDFL vs. 6500.34 ±1118.02 µm for DL. The superficial zone of thermal damage was narrower for TDFL on both days 0 and 7. The results confirm the effectiveness of both types of laser in cutting and providing hemostasis in the lungs. TDFL caused less thermal damage to the lung parenchyma than DL.

Comparison of A 1940 nm Thulium-Doped Fiber Laser and A 1470 nm Diode Laser for Cutting Efficacy and Hemostasis in A Pig Model of Spleen Surgery

Partial and total splenectomies are associated with a high risk of substantial blood loss. Lasers operating at wavelengths strongly absorbed by water have the potential to improve hemostasis and cut while providing a narrow zone of thermal damage. The aim of this study is to compare a thulium-doped fiber laser (TDFL) emitting a wavelength of 1940 nm and a diode laser (DL) operating at 1470 nm for spleen surgery in a pig model. A partial splenectomy and spleen incisions were made in 12 animals using the two laser devices. The hemostasis was evaluated visually during surgeries. Post-mortem and histopathological evaluations were done on days 0, 7, and 14 following surgery. Neither TDFL nor DL caused bleeding on day 0 or delayed bleeding. On day 14, pale streaks at the site of incision were slightly wider after cutting with DL than with TDFL. Histological analysis revealed a carbonized zone with exudation and a deeper zone of thermal tissue damage on day 0. The width of the thermal changes was 655.26 ± 107.70 μm for TDFL and 1413.37 ± 111.85 μm for DL. On day 7, a proliferation of fibroblasts and splenocytes was visible, as well as a formation of multinucleated giant cells adjacent to the residues of carbonization. The zone of thermal damage was broader for DL (1157.5 ± 262.77 μm) than for TDFL (682.22 ± 116.58 μm). On day 14, cutting sites were filled with connective and granulation tissues with the residues of carbonization. The zone of thermal damage was narrower for TDFL (761.65 ± 34.3 μm) than for DL (1609.82 ± 202.22 μm). Thus, both lasers are efficient in spleen surgery, providing good hemostasis. However, TDFL produces a narrower zone of thermal damage, which suggests its better efficiency for spleen surgery, especially when performing more precise procedures.

Lasers in Spine Surgery

Laser spine surgery has been a focus of intense interest in the lay press and among patients. On the Internet, a host of purported benefits to laser surgery exists. Lasers have long been used in pain management procedures such as percutaneous diskectomy. However, a few published articles are available on lasers in conventional spine surgery. From our review of the literature, the purported advantages of lasers, such as reduced inflammation and degeneration, are not been supported by preclinical research. The available clinical studies do not show a notable advantage for laser surgery. Moreover, the low enrollment, nonblinded, retrospective studies that are available are heavily subject to bias. The documented advantages of laser spine surgery described in the research studies are not consistent with the public's impression of its purported benefits. Furthermore, laser-specific complications are present about which patients should be informed. On the basis of the current research, we conclude that lasers add distinct potential complications without any corresponding clinical benefit. Because of the public interest, we feel that this is an important topic for the general orthopaedic community.

Photobiomodulation of human adipose-derived stem cells using 810nm and 980nm lasers operates via different mechanisms of action

Photobiomodulation (PBM) using red or near-infrared (NIR) light has been used to stimulate the proliferation and differentiation of adipose-derived stem cells. The use of NIR wavelengths such as 810nm is reasonably well accepted to stimulate mitochondrial activity and ATP production via absorption of photons by cytochrome c oxidase. However, the mechanism of action of 980nm is less well understood. Here we study the effects of both wavelengths (810nm and 980nm) on adipose-derived stem cells in vitro. Both wavelengths showed a biphasic dose response, but 810nm had a peak dose response at 3J/cm² for stimulation of proliferation at 24h, while the peak dose for 980nm was 10-100 times lower at 0.03 or 0.3J/cm². Moreover, 980nm (but not 810nm) increased cytosolic calcium while decreasing mitochondrial calcium. The effects of 980nm could be blocked by calcium channel blockers (capsazepine for TRPV1 and SKF96365 for TRPC channels), which had no effect on 810nm. To test the hypothesis that the chromophore for 980nm was intracellular water, which could possibly form a microscopic temperature gradient upon laser irradiation, we added cold medium (4°C) during the light exposure, or pre-incubated the cells at 42°C, both of which abrogated the effect of 980nm but not 810nm. We conclude that 980nm affects temperature-gated calcium ion channels, while 810nm largely affects mitochondrial cytochrome c oxidase.