Use of lasers in minimally invasive spine surgery

Orthopedics-Related Applications of Ultrafast Laser and Its Recent Advances

The potential of ultrafast lasers (pico- to femtosecond) in orthopedics-related procedures has been studied extensively for clinical adoption. As compared to conventional laser systems with continuous wave or longer wave pulse, ultrafast lasers provide advantages such as higher precision and minimal collateral thermal damages. Translation to surgical applications in the clinic has been restrained by limitations of material removal rate and pulse average power, whereas the use in surface texturing of implants has become more refined to greatly improve bioactivation and osteointegration within bone matrices. With recent advances, we review the advantages and limitations of ultrafast lasers, specifically in orthopedic bone ablation as well as bone implant laser texturing, and consider the difficulties encountered within orthopedic surgical applications where ultrafast lasers could provide a benefit. We conclude by proposing our perspectives on applications where ultrafast lasers could be of advantage, specifically due to the non-thermal nature of ablation and control of cutting.

A Narrative Review of Development of Full-Endoscopic Lumbar Spine Surgery

In the first phase of development of lumbar endoscopic spine surgery, the focus was on removal of soft disc material through the working corridor of Kambin’s triangle using transforaminal endoscopic lumbar discectomy. With the introduction of the interlaminar approach and increased interest from both industry and surgeons, there has been an exponential development of endoscopic surgical equipment and a corresponding expansion of endoscopic techniques. Endoscopic treatment strategies are applied to conditions ranging from contained prolapsed intervertebral discs to noncontained migrated herniated discs, hard calcified discs, spinal stenosis in the central or lateral recess and the foraminal and extraforaminal region, and other combinations of degenerative conditions requiring decompression or fusion surgery. The further expansion of endoscopic surgical management involving complicated spinal cases and the final quartet of trauma, infections, tumors, and possibly deformities could be the future stage of endoscopic spine surgery development. This article covers the full range of current treatment strategies and presents possible future developments of endoscopic spine surgery for the management of lumbar spinal conditions.

Outcomes with transforaminal endoscopic versus percutaneous laser decompression for contained lumbar herniated disc: a survival analysis of treatment benefit

BACKGROUND

Contained lumbar disc herniations frequently cause back- and leg pain. Clinical outcomes with surgical treatment may be affected by the size and location of the disc herniation. The surgical directly visualized transforaminal endoscopic decompression has gained acceptance and popularity, while the simplified percutaneous laser disc decompression has fallen out of favor in spite of its initial success as a minimally invasive intervention. In an attempt to better understand the durability of both procedures, the authors performed a comparative analysis of clinical outcomes in patients with contained lumbar disc herniations.

METHODS

The study population was comprised 248 patients consisting of 162 patients in the endoscopy group (group 1) and 86 patients in the laser group (group 2). Primary outcome measures were Macnab criteria. Herniations were classified as large or small. Additional parameters of advanced degeneration of the lumbar motion segment including posterior disc- and lateral recess height of <3 mm were recorded. IBM SPSS 25.0 was used for Kaplan-Meier survival analysis and cross-tabulation of these variables with statistical testing for significant associations.

RESULTS

The mean follow-up was 43.5 months. The serial time recorded for Kaplan-Meier analysis ranged from 1.5 to 84 months. The mean age was 53.37 years (standard deviation =14.65 years). The majority of patients had Excellent and Good Macnab outcomes (212/248; 85.5%) regardless of treatment. Fair and Poor results were achieved in another 36 patients (14.5%). There was a higher percentage of Excellent Macnab outcomes in the endoscopy group (94/162; 58.0%) than in the laser group (38/86; 44.2%) at a statistical significant level (P<0.0001). There was a statistically significantly higher percentage of Excellent and Good Macnab outcomes with endoscopic decompression of small paracentral herniations (97.1%; P<0.0001). Percutaneous laser decompression of large central disc herniations was not statistically better than endoscopic surgical decompression (P=0.125). Endoscopic bony and soft tissue decompression was also better than laser at alleviating symptoms in patients with reduced posterior disc- and lateral recess height with 96.7% in patients with reduced disc height of <3 mm and 94% in patients with reduced lateral recess height of <3 mm (P=0.001). Kaplan-Meier (K-M) Survival time showed longer median survival of the treatment benefit for patients who underwent visualized endoscopic surgical decompression (66.0 months) compared to median K-M survival time for percutaneous laser decompression of 17 months (P<0.0001).

CONCLUSIONS

Transforaminal endoscopic decompression for symptomatic herniated disc is an effective and durable surgical treatment to alleviate sciatica-type and back symptoms in the vast majority of patients with good long-term survival of pain relief for up to six years. Interventional percutaneous non-visualized laser decompression for the same condition may provide favorable outcomes in the short-term with soft protrusions. However, the treatment effect deteriorates much faster with a median survival of 17 months.

Devices for minimally-invasive microdiscectomy: current status and future prospects

Introduction: The current gold standard technique for lumbar disc herniation (LDH) is open lumbar microdiscectomy. The use of a tubular retractor system in the microdiscectomy technique can minimize tissue trauma by muscle-splitting sequential dilation during the surgical approach. This review aimed to describe the devices and surgical procedure of this minimally invasive microdiscectomy (MI-MD) and to discuss the pros and cons of the use of tubular retractors.Areas covered: Published medical literatures were extensively reviewed to summarize the practical devices and techniques related to the MI-MD for LDH. The placement of the tubular retractor by gradual muscle-splitting dilation technique may reduce muscle damage and postoperative wound pain. The use of flexible arm may easily change the tube direction and create a wide surgical field.Expert opinion: With reference to published literature, the MI-MD provides comparable clinical outcomes with less tissue trauma and early recovery. Development of devices for MI-MD is still ongoing. Extensive studies, including high-quality randomized trials, are required to establish a more practical and relevant MI-MD technique.

Laser-assisted endoscopic lumbar foraminotomy for failed back surgery syndrome in elderly patients

Elderly patients with failed back surgery syndrome (FBSS) or post-laminectomy foraminal stenosis have a higher risk of perioperative morbidity with extensive revision surgery. Thus, there is a need for safer and less invasive surgical options, such as laser-assisted endoscopic lumbar foraminotomy (ELF). A pin-point laser beam can allow precise tissue ablation and dissection in fibrotic adhesion tissues while preventing normal tissue injury. The present study aimed to describe the surgical technique of laser-assisted ELF and to evaluate the clinical outcomes of elderly patients with FBSS. Two-year follow-up data were collected from 26 consecutive patients aged 65 years or older who were treated with laser-assisted ELF for FBSS. Full-endoscopic foraminal decompression was performed using a side-firing laser and mechanical instruments. The average age of the patients was 70.2 years (range, 65-83 years). The mean visual analog pain score for leg pain improved from 8.58 at baseline to 3.35 at 6 weeks, 2.19 at 1 year, and 2.35 at 2 years after ELF (P < 0.001). The mean Oswestry disability index improved from 65.93 at baseline to 31.41 at 6 weeks, 21.77 at 1 year, and 20.64 at 2 years after ELF (P < 0.001). Based on the modified Macnab criteria, excellent or good results were obtained in 84.6% patients and symptomatic improvements were obtained in 92.3%. Extensive revision surgery in elderly patients might cause significant surgical morbidities. Laser-assisted ELF under local anesthesia could be a safe and effective surgical alternative for such patients at risk.

Effects of Ho:YAG Laser Ablation on Postoperative Low Back Pain and Functional Status After Transforaminal Endoscopic Lumbar Discectomy: Minimum of 2-Year Follow-Up

OBJECTIVE

To evaluate effects of holmium:yttrium-aluminum-garnet (Ho:YAG) laser ablation on postoperative low back pain and improving functional status in patients with lumbar disc herniation undergoing transforaminal endoscopic lumbar discectomy (TELD).

METHODS

The study enrolled 220 patients with lumbar disc herniation who underwent TELD or TELD with Ho:YAG laser from August 2015 to September 2016. Parameters including operative time, hospitalization, complications, and recurrence were recorded. Clinical outcomes were assessed according to visual analog scale for back pain and leg pain, Oswestry Disability Index for functional status, and modified MacNab criteria for patient satisfaction.

RESULTS

Minimal 2-year follow-up was completed by 186 patients: 76 patients who underwent TELD and 110 patients who underwent TELD with Ho:YAG laser. In the group undergoing TELD, clinical outcomes of back pain and functional status exhibited a V-shaped upward trend after surgery; there were no statistically significant differences in visual analog scale for back pain and Oswestry Disability Index scores at final follow-up compared with preoperatively (P > 0.05). In the group undergoing TELD with Ho:YAG laser, postoperative visual analog scale for back pain and Oswestry Disability Index scores significantly improved compared with preoperatively (P < 0.05) exhibiting relatively consistent improvement after surgery. The only laser-related complication was a burning sensation in the ipsilateral lower limb during the thermal procedure in 2 cases.

CONCLUSIONS

Performing Ho:YAG laser ablation with TELD prolonged low back pain relief and improved functional outcome during 2-year follow-up compared with TELD alone in patients with symptomatic lumbar disc herniation.