Lumbar spinal disc trocar placement device

#A common problem among sufferers of back pain is a prolapsed lumbar intervertebral disc, wherein a portion of the disc between two vertebrae in the lower back prolapses outward and causes pressure on a nerve. One method of treatment is by major surgery. Because of the substantial trauma caused by such surgery, it is common for the patient to experience a recovery period of ten to twelve weeks.

#Recently a new technique has been developed wherein nucleus material of the prolapsed disc is excised by percutaneous aspiration. The disc nucleus is soft and jelly-like in consistency, and can be resected and aspirated by use of a specially designed cannula. The aspiration cannula is inserted into the nucleus of the prolapsed disc with the aid of a trocar probe, prior to connection of the cannula to an aspirating machine. A major concern is precise placement of the probe to avoid nerve damage.

#Since herniation of a disc most frequently occurs between the fourth and fifth lumbar vertebrae, or between the fifth lumbar and sacral vertebrae, the insertion of the probe is very difficult. Particularly in the latter case, the probe must be inserted not only at an angle to the vertical, but also at an angle relative to the sagittal axis, in order to avoid the protective iliac crest of the sacrum. Preferably the probe is inserted at about eight centimeters away from the midline, on the coronal plane of the prolapsed disc level, at an angle of about 45 degrees. In the past, the probe has been inserted by trial and error, while monitoring its placement by fluoroscopic examination.

#FIG. 1 is a view of a patient in a prone position on a fluoroscopic examination table with a present invention stereotactic device positioned for placement of a medical probe.

#FIG. 2 is an isometric view of a trocar which is utilized as a medical probe in combination with a present invention stereotactic device.

#FIG. 3 is a top plan view of the FIG. 1 device.

#A present invention stereotactic device has dimensions which are practical for easy manipulation and placement on the skin surface of a patient, such as over the spinal area of a patient lying prone on a fluoroscopic examination table.

#A typical invention device has a base plate which has dimensions of about 20-25 centimeters in length, 2-4 centimeters in width, and 0.2-0.6 centimeter in thickness.

#A radiopaque reference line extends along the plate longitudinal axis. The radiopaque reference line can be a metal wire which is embedded in the surface of a radio-transparent base plate.