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

Summary

In paraplegic patients after spinal cord injury voluntary urination can be simulated by implanting an electronic bladder stimulator. For proper functioning the spasticity of the detrusor muscle must be eliminated by dorsal rhizotomy of the sacral roots S ₂ to S ₄ bilaterally. Additionally, voiding can be improved if the motor rootlets innervating the sphincter muscle (S 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 interlaminary 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 control and thus may be perilous for the intrathecal structures. We suggest a “microsurgically assisted” endoscopic procedure: (a) A unilateral flavectomy at the level of the medullary cone and opening of the dura are performed under microsurgical conditions. (b) A rigid endoscope is introduced allowing a percutaneous puncture of the contralateral interlaminary space under visual control. (c) Rhizotomy is then possible interchanging both approaches as working versus optical channels.