gms | German Medical Science

57th Annual Meeting of the German Society of Neurosurgery
Joint Meeting with the Japanese Neurosurgical Society

German Society of Neurosurgery (DGNC)

11 - 14 May, Essen

CO2-laser irradiation of the ligamentum flavum could be an interesting tool in minimal-invasive treatment of degenerative lumbar spinal stenosis: an in vitro study on ablation rate measurements and thermal side effects

Die Ablation des Ligamentum flavum mit dem CO2-Laser könnte eine interessante Behandlungsmodalität der degenerativen, lumbalen Spinalkanalstenose sein. Eine in-vitro-Studie zur Messung der Ablationsgeschwindigkeit und zu thermischen Nebenwirkungen

Meeting Abstract

  • corresponding author F. Rommel - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf
  • J. Herdmann - Neurochirurgische Klinik, Universitätsklinikum Düsseldorf
  • M. Werner - Center of Advanced European Studies and Research Bonn
  • M. Ivanenko - Center of Advanced European Studies and Research Bonn
  • P. Hering - Center of Advanced European Studies and Research Bonn

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 57. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie. Essen, 11.-14.05.2006. Düsseldorf, Köln: German Medical Science; 2006. DocP 12.189

The electronic version of this article is the complete one and can be found online at:

Published: May 8, 2006

© 2006 Rommel et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: Laser ablation of ligamentum flavum could be an interesting alternative to the established mechanical procedures in the treatment of lumbar spinal stenosis. The object of our series of investigation was to define the nature of removal of ligamentum flavum by CO2-laser ablation in terms of three characteristics: first, the histological characteristics of tissue removal and the possible evidence of thermal damage second, the effect of additional water-spray on thermal side effects and ablation efficacy and third, the quantification of effectiveness of ablation by measuring the ablated tissue volume over time.

Methods: Experiments were performed on ligamentum flavum harvested from spinal segments L3/L4 and L4/L5 obtained from 5 fresh human cadavers. A commercial SC x 30 CO2 laser (λ=10,6 µm) from Rofin-Sinar was used for all experiments. The used pulse duration was 44 µs and 56 µs. Irradiation was performed with or without water-spray. The average power at a repetition rate of flaser=50 Hz was 3,2 and 1,8 W. Lased samples were processed for H&E staining and histological examination. Digital pictures from histological slices were obtained and analysed with a graphical software to perform computed surface measurements and calculate ablation volumes.

Results: Dry irradiation causes significant thermal side effects whereas only minimal collateral damage is observed when an additional waterspray is applied. The use of an additional water spray does not only reduce thermal side effects significantly but also increases effectiveness of the ablation process. With an average laser power of 3,2 W used in our experimental setting a volume of 1 cm3 is ablated in 60 minutes.

Conclusions: Our data show that short-pulsed CO2-laser ablation at 10,6µm with the use of an additional waterspray could be an effective tool to ablate human ligamentum flavum without significant thermal damage to the surrounding tissue layers.