&gt;  don&#x27;t see how this is suppose to work when we can not fix quadriplegic people.<p>folks with spinal cord injuries are often that way not due to injury caused by trauma itself, but due to their bodies reaction after that trauma. Swelling and inflammation near the damage leads to contusion of nervous tissue and the formation of scar-tissue like plaques that reduce the effectiveness of myelin as an electrical material. We can&#x27;t repair that form of damage yet, only hope to limit it through quick response after trauma.<p>The HEAVEN paper goes through the steps they are going to take to make sure that the body is not allowed to react in such a way. A very sharp blade is used and a chemical, PEG, is used to refuse the nervous tissue within a small very small time-frame, along with chilling the patient and other protocols.<p>tl;dr : a spinal cord injury is tricky because the overall amount of bandwidth between the brain and the nervous system is reduced (so-far) irreversibly.<p>This surgery is tricky (amongst a zillion other reasons) because rather than dealing with a reduction in bandwidth, it&#x27;s hoped that the brain is plastic enough to be able to deal with the different spatial characteristics of the patients nervous tissue and matching body.<p><i>even shorter tl;dr</i> : it&#x27;s easier to manage an injury you made than one you were handed.<p>(p.s. tetra&#x2F;quad&#x2F;para-plegia are symptoms, not diseases. the causes are numerous and plentiful. i&#x27;m only using spinal cord injury as an example because I am more familiar with it than other diseases that cause paralysis)