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Histological and magnetic resonance imaging alterations after irradiation of meniscus using Holmium:YAG laser
O S Atik1, D Erdogan, S Omeroglu
1Department of Orthopaedic Surgery, Gazi University Medical Faculty, Ankara, Turkey. atik@tr.net
Objective:
The authors performed an experimental and a prospective clinical study to evaluate the histological and magnetic resonance imaging (MRI) alterations after irradiation of meniscus using holmium:YAG (Ho:YAG) laser VersaPulse Select 60 watts and InfraTome Delivery Systems 30 degrees Handpiece (spot size at fiber tip 0.4 mm; Coherent Medical, Palo Alto, CA).
Background Data:
Recently, some authors reported a few cases with articular cartilage damage or paraarticular osteonecrosis following arthroscopic knee surgery in which the laser was used to assist in the treatment of meniscal pathology.
Methods:
Meniscus specimens in saline immersion were exposed to Ho:YAG laser irradiation. The laser wavelength was 2.1 microm and pulse duration was 250 microsec. Power settings were 1-1.5 joules per pulse and 10-15 Hz. Total laser energy used in these procedures was 2, 3.5, and 6 K joules. Eight patients with meniscal problems underwent arthroscopic partial meniscectomy using Ho:YAG laser. Total laser energy used for these surgeries was 1.5-2.5 K joules. MRI was performed preoperatively and at 6 months postoperatively.
Results:
At higher energy levels (more than 3 K joules), separation of the gap between the collagen fibers, and a three-dimensional dispersion in the striation were observed on electron microscopic evaluation of meniscus specimens. No patient had abnormal signals in MRI (a sign of articular cartilage damage or osteonecrosis) following arthroscopic laser surgery.
Conclusion:
When higher energy level is required, conventional instruments should be preferred in the treatment of meniscal lesions. Laser should be reserved for the posteriorly located and smaller meniscal lesions.
Insights
Holmium:YAG laser irradiation of meniscus can cause histological changes at higher energy levels. Arthroscopic laser surgery showed no MRI evidence of cartilage damage or osteonecrosis in patients.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Laser Medicine
Background:
- Concerns exist regarding articular cartilage damage and osteonecrosis after laser use in arthroscopic knee surgery for meniscal pathology.
- Previous reports highlight potential adverse effects of laser interventions.
Purpose of the Study:
- To evaluate histological and MRI alterations in meniscus following holmium:YAG (Ho:YAG) laser irradiation.
- To assess the safety and efficacy of Ho:YAG laser in arthroscopic partial meniscectomy.
Main Methods:
- Experimental study involving Ho:YAG laser irradiation of meniscus specimens in saline.
- Prospective clinical study of eight patients undergoing arthroscopic partial meniscectomy using Ho:YAG laser.
- Histological evaluation (electron microscopy) and pre- and post-operative MRI scans at 6 months.
Main Results:
- Higher Ho:YAG laser energy levels (>3 K joules) induced separation of collagen fibers and dispersion in striation on electron microscopy.
- No patients exhibited abnormal MRI signals indicative of articular cartilage damage or osteonecrosis post-surgery.
Conclusions:
- Conventional instruments may be preferable for meniscal lesions requiring higher laser energy.
- Ho:YAG laser application should be reserved for smaller, posteriorly located meniscal lesions.
