Xiao Procedure
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THE XIAO PROCEDURE FOR RESTORING BLADDER & BOWEL FUNCTION

Laurance Johnston, Ph.D.

As reviewed elsewhere, peripheral-nerve rerouting has considerable potential to restore some function after SCI. In the previously discussed procedures, peripheral nerves 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 a paralysis-affected muscle. For example, a still functional nerve to the rib cage can be rerouted and connected to a paralysis-affected nerve that controls urination or, alternatively, a leg muscle. Many rerouting permutations exist, which have restored some function at most levels of injury.

However, the procedures described here are fundamentally different in that the rewired nerves are both below the injury site. Nevertheless, through skin stimulation, this below-the-injury rewiring can trigger voluntary bladder and bowel function.

The driving force behind the development of these function-restoring procedures has been Dr. Chuan-Guo Xiao. Although originally from and currently working in China, he spent many years in the US fine-tuning his methodology at the New York University School of Medicine. In fact, his pioneering work was first funded by PVA. According to Xiao, “Without the first two grants from PVA, I don't think I could have gotten the two big grants from the National Institutes of Health, which allowed me to transfer the idea from laboratory bench to bedside.” He adds “I have been really grateful to PVA for funding an idea from a Chinese urology fellow with even worse English than now.”

Description of Procedures

Although there are a number of nerve-reconnection possibilities, Xiao frequently cuts the lumbar-level L5 ventral nerve root and connects it end-to-end to a cut sacral-level S3 (or S2) ventral nerve root, which innervates the bladder. (The ventral and dorsal roots contain nerves that leave and enter the spinal cord, respectively). After the axons within this surgically connected nerve are given the time to regenerate to the target site, the patient can initiated voiding by scratching or gently squeezing for about 10 seconds their legs or buttocks, i.e., the skin associated with the L5 dermatome.

Basically, these actions trigger a sensory signal that enters the cord via the L5-dorsal root, in turn, stimulating nerves that leave the cord through the L5-ventral roots now connected to the bladder-controlling S3-ventral nerve root. Provided this area of rerouting is undamaged, the procedure is suitable for most injury levels. Because the procedure does not restore bladder sensation, individuals must consciously initiate the triggering process to urinate.

In 2003 and 2006 articles, Xiao reported the results of treating 15 patients with ASIA-A-complete injuries with the procedure [ASIA-impairment scale classifies injuries from grade A (complete) to grade E (recovery)]. Injuries ranged from cervical C4 to thoracic T12; in other words, all were above the nerve-rerouting area. Age ranged from 25 to 55 (mean 39) years, and the time between injury and surgery averaged 6.8 years. Patients were monitored for three years.

Of the 15 patients studied, 10 recovered bladder-storage and -emptying function starting about a year after surgery, the time it takes for neuronal axons to grow the 150 millimeters (~ 6 inches) to their target site. Residual urine decreased from 332 to 31 milliliters, and urinary-tract infections became negligible. In addition to these 10, two other patients recovered partial function. These two required electrical stimulation of the skin to initiate voiding, and, although residual urine volume was less, they still retained over 100 milliliters. Of the three remaining patients, one was lost to follow-up, and two did not accrue benefits, apparently due to poor rerouting connections. Overall, there were no significant short- or long-term complications.

Before surgery, six of the 12 patients who eventually recovered some bladder control had elevated serum creatine levels, an indicator of kidney problems. A year and half after the procedure, their creatine levels returned to normal. In addition, patients who regained bladder control also regained bowel control.

In a 2010 update posted on the SCI CareCure discussion forum, Xiao indicated that since 2000 he and his colleagues have cumulatively treated 350+ patients with SCI and 1,500+ patients with spina bifida – a birth defect which results in an incompletely developed spinal cord.  Overall success rate exceeded 80%. In addition to restoration of bladder and bowel function, he noted that 20-25% of the patients regained some sexual functioning. He believes this sexual improvement is due to the overall enhancement of the patients’ physical condition after bladder and bowel function have been normalized. 

To further disseminate his function-restoring procedures, Xiao has trained numerous neurosurgeons in North America and Europe, including the following:

Michigan: As reported on the National Institutes of Health’s clinical trial registry and elsewhere, Drs. Kenneth Peters and colleagues initiated a study evaluating Xiao’s procedure in 12 subjects with either SCI (3) or spina bifida (9). Preliminary results indicate that bladder and bowel function was improved in many of the subjects. Peters emphasized, however, that careful follow-up will be needed to understand the rerouting procedure’s ultimate impact.

Louisiana: Drs. John Mata and Ravish Patwardhan used the procedures to restore bladder function in a seven-year-old girl who had been shot five years earlier.

Florida: Dr. Yves Homsy and colleagues (Florida) have initiated a three-year study of the procedures in children with spina bifida and SCI.

It should be noted that outside of China, the availability of the procedure is primarily limited to a research protocol.

Conclusion

As someone who has been involved in disability research for many years, I’m amazed by how many promising, function-restoring therapies are emerging throughout the world for SCI, a disorder once considered so hopeless its cure was called the “Holy Grail” of neurological research. Although none are an all-encompassing “cure,” the dam is slowly, but inevitably, crumbling. It may be only a small therapeutic trickle now, but it will become a flood. What is especially promising in this case is the international collaboration involved in developing and disseminating the procedures. Because SCI bows to no flag, we need more of such collaboration.

REFERENCES

Xiao C-G, Du M-X, Dai C, et al. An artificial somatic-central nervous system-autonomic reflex pathway for controllable micturition after spinal cord injury: Preliminary results in 15 patients. J Urol 2003; 171(6): 1237-1241.

Xiao C-G. Reinnervation for neurogenic bladder: historic review and introduction of a somatic-autonomic reflex pathway procedure for patients with spinal cord injury or spina bifida. Eur Urol 2006; 49(1): 22-29.

Xiao procedure discussed on CareCure Forum, http://sci.rutgers.edu/forum/showthread.php?t=132379. [Accessed June 2, 2010].

Xiao C-G. A somatic-autonomic reflex pathway procedure (Xiao Procedure) for refunctionization of bladder and bowel in SCI and spina bifida. http://webcasts.prous.com/netadmin/webcast_viewer/Preview.aspx?type=0&lid=10196&pv=2&preview=False&idcl=1 [Accessed June 19, 2010].

Lumbar to sacral ventral nerve re-routing, http://clinicaltrials.gov/ct2/show/NCT00378664 [Accessed June 17, 2010].

Adapted from article appearing in October 2010 Paraplegia News (For subscriptions, call 602-224-0500) or go to www.pn-magazine.com

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