Laurance Johnston, Ph.D.

Peripheral-nerve rerouting is an exciting surgical procedure that has considerable potential for restoring significant function after spinal cord injury (SCI). Basically, with this procedure, peripheral nerves (i.e., those outside of the spinal cord and brain) emanating from the cord above the injury site are surgically rerouted and connected to those below the injury site. This reestablishes a functional neuronal connection from the brain to previously dormant muscle or sensory systems.

A key force behind developing this procedure into a real-world SCI therapy has been Dr. Shaocheng Zhang,  of Changhai Hospital, Shanghai, China. Because he has treated over a 100 people with SCI, he has made routine a seemingly challenging neurosurgical procedure. In addition to Zhang’s work, Dr. Giorgio Brunelli, University of Brescia, Italy has greatly contributed to developing the procedure.

After I met Zhang at a World Health Organization (WHO) SCI conference, he invited me to Shanghai last December to become the first American to observe firsthand his peripheral-nerve-rerouting surgery. Because his hospital, Shanghai’s largest, is military affiliated, this invitation to a Paralyzed Veterans of America (PVA) representative clearly was a bridge-building, goodwill gesture. It would certainly be a promising sign for the future if military-affiliated organizations from two countries that have had historically some animosity could work together to find solutions for a problem that bows to no flag or political system

East Meets West:

An impressively modern city with 16-million residents, Shanghai is located near the juncture of the Yangtze River and the East China Sea. As China enters the World Trade Organization, Shanghai seems destined to reclaim its historical role as the country’s most international city.  Its downtown skyline - with the world’s third tallest skyscraper and an even-taller, space-needle-like tower - rivals that of virtually any city.

Although few residents spoke English, its presence was everywhere. For example, many road, building, and billboard signs were in English; police cars were prominently labeled with the word “police”; airplane and train schedules were announced in English; Christmas carols were piped-in at the ubiquitous, familiar fast-food restaurants; and rock, rap, and jazz music was played on the radio.

Considerable hospitality and friendship were extended to me, including much sympathy for the World Trade Center terrorist attack. Overall, there seemed to be a sincere desire to move into the twenty-first century as friends of America, not adversaries, and to work together for mutually beneficial economic growth. 

Procedure:

Unlike spinal cord nerves, peripheral nerves have considerable regenerative potential and the ability to establish new neuronal connections.  Building upon these capabilities, Zhang surgically reroutes and connects a peripheral nerve that emanates from the spinal cord above the point of injury to nerves or nerve roots below the injury. Hence, a viable neuronal connection from the brain to the previously paralysis-affected body area is created, restoring some function.

The nature of the restored function depends upon the specific functions that the target nerves serve (e.g., leg muscle function, bladder and bowel control, sensation, etc). For example, the rerouted nerve could be connected to a nerve that controls urination, or it could be reconnected to nerve that controls upper leg muscles.

Alternatively, if the rerouted nerve is connected to a general nerve root system, function in the overall physical area controlled by this system will be restored. One surgical rerouting designed to restore a specific function does not preclude a future rerouting to restore a different function. (Because this article extensively refers to different spinal cord and dermatome sensation levels, readers are encouraged to consult the illustrations for reference).

Many possible rerouting arrangements exist. Zhang commonly reroutes one of the intercostal nerves that lead from the spinal cord around each rib to the sternum. If the intercostal nerve is not long enough to reach the target nerve site below the injury level, a segment of the sural nerve (isolated from the calf) is attached to the intercostal nerve.

If the injury site is above the thoracic area where the intercostal nerves originate, other peripheral nerves can be selected. For example, in several cases, Zhang has rerouted the ulnar nerve, which leads down to the wrist originating from the C8-T1 spinal cord region, a procedure Italy’s Brunelli has also used.

In addition to the intercostal and ulnar nerves, peripheral-nerve-rerouting options can restore function for virtually any level of injury. For example, in high-level injuries, functional peripheral nerves above the injury site (e.g., cervical plexus nerve branches originating from the higher cervical regions) can be connected to nearby dysfunctional nerves below the injury site (e.g., brachial plexus nerves originating from the lower cervical regions), potentially restoring respiratory ability to a previously ventilator-dependent quadriplegic.

Zhang’s patients have lost little function in the original area served by the donor nerve because of nerve redundancy, the availability of multiple nerve branches, or the creation of alternative connections. For example, rerouting one of the many rib-associated, intercostal nerves will result in little functional loss. In the case of ulnar nerve rerouting, alternative nerve connections can be created to the hand and wrist.

Although improvement in some cases is quickly apparent, restored function will gradually accrue over 12-18 months depending upon the specific surgical complexity.

While the procedure isn’t precluded for older patients, younger patients with greater inherent regenerative potential often benefit more from peripheral nerve rerouting.  In addition, as more time passes after injury, the surgery may become less feasible, especially for lower-level injuries.

In spite of intimidating neuroanatomical terminology, peripheral-nerve rerouting is conceptually relatively easy to understand. For example, visualize a house in which the power to the back bedroom is lost (i.e., area below the injury) due to a burned-out master electrical cable (i.e. the spinal cord injury). Instead of fixing the master cable, you disconnect the wire that powers the living-room television (i.e., a nerve to the rib or wrist region), tunnel it through the walls, and splice it directly to the bedroom wiring, circumventing the damaged section of master cable.

If the redirected wire isn’t long enough to reach the bedroom, you splice an intervening piece of wire (i.e., the sural nerve) cut out from a part of the basement you rarely use. In order not to lose television function, you simply insert the TV plug into another living room outlet (i.e., establish alternate connections). Although this procedure may not be as desirable as replacing the master cable, you, nevertheless, now have power in the back bedroom.

Case Studies:

I observed Zhang carry out peripheral nerve-rerouting operations in three individuals with SCI. In addition, I have interacted with two former patients.

Case #1:  Last year, 31-year old Yang acquired a T9-10 injury after falling at work.  The surgery’s primary goal was to restore some of Yang’s lower extremity function, especially bladder control. Yang’s 3-4-hour surgery was the most involved of the three operations I observed. 

Initially, Zhang detached for later use a sural nerve segment from Yang’s calf.  He then proceeded to isolate an intercostal nerve from Yang’s rib region, maintaining the nerve’s connection to the spinal cord. Next, Zhang exposed Yang’s sacral nerve roots that control urogenital muscles. After he sutured the detached sural nerve segment to the intercostal nerve to make it long enough to reach this sacral region, the combined intercostal-sural nerve was connected to the sacral nerve roots.  Yang demonstrated some restored sensation in body areas controlled by the recipient sacral nerves (see dermatome chart) hours after surgery (This quick initial recovery is due to decompression).

Case 2:  Although 31-year old Wang had retained some hip function after his lumbar injury, he had lost bladder control. In this case, a nerve that led to Wang’s functional hip was connected to a nearby dysfunctional nerve that served the urinary system. Specifically, the gluteus inferior nerve (originating from the L-5, S-1,2 spinal-cord level) that innervates the gluteus maximus muscle was connected to the injury-affected pudendal nerve (originating from the S-2,3,4 spinal-cord level) that serves the urogenital muscles. Because of the nerves’ physical proximity, no intervening graft was needed. Overall, this was a much less complicated operation, requiring only an hour to complete.

Case 3: Although involving a peripheral nerve SCI treatment, the third surgery represented a fundamentally different procedure, which Zhang has performed in more than 12 patients, and is included because of its radical nature.

This case involved 36-year old Chu, who had recently become a C-4 quadriplegic due to a construction accident. In Chu’s operation, detached, sural nerve segments were inserted directly into his injured spinal cord. These segments were initially scraped to expose nerve fibers and, after scar tissue was removed from and incisions made in the remaining cord, inserted lengthwise without suturing. The next day, Chu, who had previously possessed only residual bicep function, was able to move his hands.

Follow-Up Case 1:  Huocheng acquired a T11-12 injury in a 1997 motorcycle accident when he was 25. The following year, Zhang rerouted an intercostal nerve from one side of Huocheng’s body to the lumbar nerve roots and, in turn, an intercostal nerve from the opposite side of his body to the sacral nerve roots. These two nerve reroutings together restored much of Huocheng’s lower extremity function. For example, he now has considerable upper-leg muscle control  and sensation down to his feet. Huocheng can now walk with crutches without leg braces and has greatly improved bowel and bladder control.

Follow-Up Case 2: In 1989, Bido became injured in the lumbar region at age 17 after a car accident in Iceland. After rehabilitation, she was able to walk using hip muscles in conjunction with stiff braces that extended to her waist. Bido is the daughter of Audur Gudjonsdottir, who was recently honored as Iceland’s “Woman of the Year” for ongoing SCI advocacy efforts, including spearheading the aforementioned WHO conference.

After a facilitating request from Iceland’s President Vigdis Finnbogadottir, Zhang traveled to Iceland in 1995 to surgically repair and remove scar tissue from Bido’s spinal area. Audur, a nurse, indicated that so much scar tissue was removed that “both of my hands were full of it.” That operation alone restored some function. Audur believes that “each individual who sustains SCI should have an operation like that some time after the accident.” She adds: “as expected, the body attempts to heal itself with scar tissue, which is a band aid. When the band aid is removed and the pressure alleviated from the spinal cord or the nerve roots, things begin to work again.”

In 1996, Zhang returned to Iceland to reroute Bido’s intercostal nerve to her lumbar nerve roots. As a result of these surgeries, Bido’s ambulatory ability has greatly improved even though the surgeries occurred many years after injury. According to Audur, “Bido has motor function in both legs down to the ankles. As such, she is now able to walk using braces that end below the knees. She bends both knees during walking, and her balance is much better.”

Conclusion:

Increasingly, it seems that the most exciting SCI therapeutic breakthroughs are originating in numerous places other than America. Although American neuroscience is unrivaled, for a variety of reasons - the pros and cons of which can be debated extensively - it has been difficult to translate this scientific excellence into real-world SCI therapies. Even when the initial scientific breakthrough happens in America, the bench-to-bedside transfer of knowledge that transforms this breakthrough into useful therapies often seems to occur elsewhere.  

One potential reason has been implied by Christopher Reeve, the well-known actor with SCI whose foundation greatly contributes to and influences the nature of SCI research in this country. Commenting on a peripheral nerve-routing operation carried by Italy’s Brunelli, Reeve has stated “I think it is pretty immoral because you have to follow a sequence. You’ve got to go from rats, a lot of rats. Then you have to go to bigger animals, pigs hopefully, not monkeys. You’ve got to demonstrate safety and efficacy.” (see http://care cureatinfopop.com).

Reeve’s opinion reflects the prevailing conservative approach of the American SCI research community, which believes that serving its needs for scientific rigor is the best way to serve the needs of people with SCI for new therapeutic options. However, as someone who was extensively involved in setting SCI research priorities in this community, I believe that the cows will come home a long, long time before the pigs tell us anything truly useful.

Dr. Zhang’s peripheral-nerve-rerouting approaches appear extraordinarily promising for restoring significant function after SCI.  In the spirit of cooperation, we need to open-mindedly develop synergistic, mutually beneficial collaborations that can evaluate innovative procedures such as his and, more importantly, facilitate new understandings. One of Zhang’s foremost desires is to see a professional exchange in which his colleagues and their American counterparts would be able to visit and learn from each other’s experience.

Society’s continued evolution into a “global village” has allowed us to share technology so we can order a comparable McDonalds Big Mac hamburger regardless of whether we are in China or America. Given that we can share such culinary technology, it would be an absurd sense of priorities not to be able to somehow share SCI therapeutic knowledge that would benefit so many.

If we can bring together all the exciting SCI developments throughout the world, restoration of function would no longer be some distant pie-in-the-sky dream but a real-world expectation now. It’s time to pull it all together. No more excuses. Let’s roll.

Acknowledgements & Resources: Special thanks are extended to Dr. Shaocheng Zhang, his colleagues, and superiors for extensive hospitality. Dr. Zhang can be reached by mail at 32-43-301, Zhongyuan Rd., Shanghai 200433, China or by fax at 001-86(country code)-21(city code)- 65346003.

For more-technical summaries of Dr. Zhang’s peripheral nerve rerouting procedures, click here.

For those who are potentially interested in this peripheral nerve rerouting surgery, Zhang is willing to consider foreign patients, who would stay in a modern foreign-guest clinic or is willing to travel to America to carry out the surgery if an appropriate collaborative relationship can be established with an U.S. hospital.

Adapted from article appearing in Paraplegia News, April, 2002 (For subscriptions, contact www.pn-magazine.com).