Innovative grid positioning system (GPS) guidance for minimally invasive spinal surgery.

Symptomatic degenerated spinal discs and spinal stenosis are common problems that can often be treated conservatively, but some require decompressive spinal surgery for relief. Traditional open spinal discectomy is associated with significant tissue trauma, higher morbidity and complication rates, a longer convalescence, and even destabilization of the spine. The trend of spinal surgery is rapidly moving toward less traumatic minimally invasive spine surgery (MISS).1,2 The problem that faces the surgeon performing endoscopic MISS is that it is done with limited surgical exposure and visualization of the surgical field. The surgical field can only be viewed through an endoscope to correlate the lesion/pathology in relationship to imaging studies aided by C-arm fluoroscopy. In response, a logical and simple Grid Positioning System (GPS) was developed to provide a precise surgical trajectory/approach for the disc lesion to undergo decompression. GPS involves 3D geometric triangulation of 3 different planes guided by fluoroscopy for introduction of surgical instruments along a geometric line toward the lesion without compromising healthy anatomical structures. This system facilitates MISS, especially in the morbidly obese. In this chapter, we will describe the GPS system and its application to aid in facilitating minimally invasive decompressive spine surgery for alleviating symptoms of degenerative spinal disease, herniated disc, and spinal stenosis, while avoiding the complications and risks of conventional more traumatic spinal surgery and fusion.