Spinal Endoscopy in Fixed Human Cadavers: Preliminary Findings with Possible Implications for Implanting Bladder Stimulators in Paraplegic Patients

Abstract

Summary In paraplegic patients after spinal cord injury voluntary urination can be simulated by im­ planting an electronic bladder stimulator. For proper functioning the spasticity of the detrusor muscle must be eliminated by dorsal rhizotomy of the sacral roots $2 to $4 bilaterally.Additional­ ly, voiding can be improved if the motor rootlets innervating the sphincter muscle ($ 2) are also dissected on both sides. The commonly used approach for these procedures at present is a laminectomy of at least two vertebral arches at the level of the medullary cone. The aim of our study is to develop a minimally invasive method applying endoscopic techniques. Using fixed human cadavers we tested a flexible and a rigid endoscope. Based on our first experience the rigid instrument was preferred. A bilateral­ biportal approach was most apt. Even interlami­ nary spaces at upper lumbar/lower thoracic levels could easily be punctured percutaneously with trocars of 5 mm in diameter. However, such a percutaneous puncture is not under visual con­ trol and thus may be perilous for the intrathecal structures. We suggest a "microsurgically assis­ ted" endoscopic procedure: (a) A unilateral flavec­ tomy at the level of the medullary cone and opening of the dura are performed under micro­ surgical conditions. (b) A rigid endoscope is intro­ duced allowing a percutaneous puncture of the contralateral interlaminary space under visual control. (c) Rhizotomy is then possible inter­ changing both approaches as working versus optical channels.