The past, present and future of minimally invasive spine surgery: a review and speculative outlook.

In the last 25 years of spinal surgery, tremendous improvements have been made. The development of smart technologies with the overall aim of reducing surgical trauma has resulted in the concept of minimally invasive surgical techniques. Enhancements in microsurgery, endoscopy and various percutaneous techniques, as well as improvement of implant materials, have proven to be milestones. The advancement of training of spine surgeons and the integration of image guidance with precise intraoperative imaging, computer- and robot-assisted treatment modalities constitute the era of reducing treatment morbidity in spinal surgery. This progress has led to the present era of preserving spinal function. The promise of the continuing evolution of spinal surgery, the era of restoring spinal function, already appears on the horizon. The current state of minimally invasive spine surgery is the result of a long-lasting and consecutive development of smart technologies, along with stringent surgical training practices and the improvement of instruments and techniques. However, much effort in research and development is still mandatory to establish, maintain and evolve minimally invasive spine surgery. The education and training of the next generation of highly specialized spine surgeons is another key point. This paper will give an overview of surgical techniques and methods of the past 25 years, examine what is in place today, and suggest a projection for spine surgery in the coming 25 years by drawing a connection from the past to the future.

A spectroscopic approach to monitor the cut processing in pulsed laser osteotomy.

During laser osteotomy surgery, plasma arises at the place of ablation. It was the aim of this study to explore whether a spectroscopic analysis of this plasma would allow identification of the type of tissue that was affected by the laser. In an experimental setup (Rofin SCx10, CO(2) Slab Laser, wavelength 10.6 µm, pulse duration 80 µs, pulse repetition rate 200 Hz, max. output in cw-mode 100 W), the plasma spectra evoked by a pulsed laser, cutting 1-day postmortem pig and cow bones, were recorded. Spectra were compared to the reference spectrum of bone via correlation analysis. Our measurements show a clear differentiation between the plasma spectra when cutting either a bone or a soft tissue. The spectral changes could be detected from one to the next spectrum within 200 ms. Continuous surveillance of plasma spectra allows us to differentiate whether bone or soft tissue is hit by the last laser pulse. With this information, it may be possible to stop the laser when cutting undesired soft tissue and to design an automatic control of the ablation process.