Minimally Invasive Intraoperative Stiffness Measurement of Lumbar Spinal Motion Segments

Abstract

In the moderately degenerated spine, stiffness decreases significantly after microdiscectomy. Control for muscle relaxation is essential when measuring in vivo spinal stiffness. The new spinal spreader was found to provide reliable data. This spreader could be used in further studies for objective decision-making about additional stabilization systems after microdiscectomy.

A structured review of spinal stiffness as a kinesiological outcome of manipulation: Its measurement and utility in diagnosis, prognosis and treatment decision-making

“…The measurement methods were diverse and thus were categorised for comparison by separating them into those that measured stiffness via practitioner palpation and judgment (n = 13, Table 1) and those that used instrumentation (n = 62), and further subdividing instrumented measurement methods into three types. The instrumented studies were categorised into those that measured accessory movement at a particular spinal level (n = 42, Table 2), those that measured physiological movement of the spine with or without measurement of muscle activity (n = 13) (Brown et al, 2006;Brown and McGill, 2008Cholewicki et al, 1999Cholewicki et al, , 2000Drake et al, 2008;Essendrop et al, 2002;Gombatto et al, 2008a,b;Green et al, 2002;Hodges et al, 2009;Lee et al, 2006), and those that measured stiffness intraoperatively (n = 7) (Ambrosetti-Giudici et al, 2009;Brown et al, 2002a;Ebara et al, 1992;Hasegawa et al, 2008;Krenn et al, 2008;Nathan and Keller, 1994;Takano et al, 2006). Thirty-seven of these studies addressed factors that affect the instrumented measurement of spinal stiffness (Table 3), with 9 including participants with spinal pain and 28 including asymptomatic participants.…”

Intraoperative determination of the load–displacement behavior of scoliotic spinal motion segments: preliminary clinical results

“…1a). These modifications were developed jointly with the University of Applied Sciences in Biel, Switzerland and have been published by Krenn et al [15]. Both the distractor and the two vertebrae of a motion segment were tracked with an optoelectronic camera (Optotrack 3020, Northern Digital Inc., Waterloo, Canada).…”

Combining 3D tracking and surgical instrumentation to determine the stiffness of spinal motion segments: A validation study

“…The strain gauges were calibrated to measure the force applied at the tips and the hall sensor was calibrated to measure the opening of the tips. These modifications were developed in collaboration with the University of Applied Sciences in Biel, Switzerland, and have been previously described in detail by Krenn et al [9]. This configuration was modified to include two cruciform marker shields, each with four infrared light emitting diodes (LEDs), to guarantee sufficient camera visibility.…”

“…Brown et al [6,7] and Hasegewa et al [8] developed motorized systems where distractor arms exhibit a translation along a rail. Krenn et al [9] recently modified a spinal spreader to measure force and displacement between the spinous processes, which was later further developed by Ambrosetti-Giudici et al [10]. All of the above mentioned setups performed a distraction between the spinous processes in the sagittal plane to induce a flexion and assumed a planar loading and motion.…”