Xiao Procedure

WHAT IS THE XIAO PROCEDURE?

The Xiao procedure is a treatment method for neurogenic bladder in patients with spinal cord injury (SCI) or spina bifida. It utilizes the motor axons of a somatic reflex arc to regenerate into autonomic preganglionic nerves, re-innervating the bladder parasympathetic ganglion cells and transferring somatic reflex activity to the bladder smooth muscle. This procedure aims to restore voluntary control and voiding in patients with neurogenic bladder.

In recent years, Professor Xiao and his team have focused on new research, broadening the use of the Xiao procedure in obstetrics, gynecology, gastrointestinal surgery, and bone cancer treatment. They have effectively tackled complex medical issues such as postoperative urinary and bowel problems in radical surgeries for cervical cancer, rectal cancer, and bone tumors.

The Surgical Procedure Involves:

Making a vertical incision of 3-5cm to expose the left lumbosacral nerve root.
Using nerve electrophysiology to electrically stimulate each nerve root individually and observe the muscle electromyogram to identify the anterior root of the left L5 or S1.
Separating and cutting half or a quarter of the root at the intervertebral foramen.
Sequentially locating and cutting the anterior root of the left S3 at its origin from the spinal cord.
Performing microsurgical anastomosis of the distal end of the S3 root to the proximal end of the L5 root.

This procedure establishes the “skin-spinal cord central-bladder reflex arc,” which induces urination by stimulating the corresponding skin area of the lower limbs, thereby addressing urinary dysfunction.

L5: The fifth lumbar vertebra in the spine, located in the lower back, supports the upper body and aids in movement.
S1: The first sacral vertebra, part of the sacrum, supports the lower back, hips, and legs, crucial for lower body stability and movement.
S3: The third sacral vertebra, part of the sacrum, connects the spine to the pelvis, assisting in supporting the upper body weight. S3 is primarily involved in controlling bladder and rectal functions.

Xiao Procedure Principle

Reflex is the fundamental way through which nerves control the body’s physiological functions. A reflex arc typically consists of a receptor, sensory nerve, reflex center, motor nerve, and effector. The normal voiding reflex is controlled by the higher voiding center located in the brainstem and cerebral cortex, completing the voiding reflex primary center in the sacral spinal cord. When the bladder is full, the stretch receptors in the bladder wall are stimulated and excited. The impulse travels to the higher center generating the urge to void. The central system determines the readiness to void, sending nerve impulses through the descending pathway to the primary voiding center in the spinal cord. Subsequently, parasympathetic neurons send nerve impulses causing the bladder’s detrusor muscle to contract, while the urethral sphincter relaxes, allowing urine to pass through the urethral opening. Injuries and diseases at higher spinal levels disrupt the connection between the higher and primary centers, resulting in the loss of voluntary voiding ability in the bladder.
Xiao Chuan-Guo treats voiding dysfunction caused by SCI by cutting one side of the L5 anterior roots and anastomosing them with the S2 and/or S3 anterior roots controlling the detrusor muscle. The integrity of the L5 posterior root is maintained undamaged. This is known as the “body nerve-central nerve-autonomic nerve reflex arc” or “skin-central nerve-bladder reflex pathway.” By stimulating the corresponding skin area innervated by the L5 posterior root, nerve impulses are transmitted from the L5 posterior root. Passing through the primary voiding center in the spinal cord, it triggers the anterior horn neurons at L5 to generate action potentials, transmitted via the L5 anterior root to the bladder, causing detrusor muscle contraction and achieving controlled voiding. Acetylcholine serves as the neurotransmitter for both the body and autonomic nerves. Therefore, in the reconstructed reflex arc, nerve impulses generated by stimuli sensed by receptors (skin) can smoothly transmit through the central spinal cord to the effector (bladder detrusor muscle). Hence, the Xiao procedure reflex arc is scientific and feasible.

Cao Xiao-Jian （or Cao XJ）Nanjing Medical University First Affiliated Hospital

US Pilot Study of Lumbar to Sacral Nerve Rerouting to Restore Voiding and Bowel Function in Spina Bifida

Throughout the last century, numerous studies have investigated the effects of bladder reinnervation using somatic-autonomic nerve cross union in both animals and humans. In 1967, Carlsson and Sundin detailed a case involving a four-year-old spina bifida patient who underwent motor root rerouting, leading to reflex micturition and bladder sensation after eight months of recovery. While initial interest in nerve rerouting existed, Xiao and Godec further explored this concept through animal studies confirming bladder reinnervation and reflex micturition. Subsequent reports indicated early clinical success in humans with spina bifida.

Understanding the clinical significance of demonstrating a cutaneous-to-bladder reflex on UDS is challenging. At one year, eight of thirteen subjects had a reproducible reflex. Although this reflex provided some evidence of bladder reinnervation, its presence did not always align with the clinical response. By three years, this reflex was only evident in two patients, yet most, including these two, could void efficiently using some degree of Valsalva. Comprehending the emergence and apparent suppression of this reflex over time is complex. It is possible that the bladder is no longer innervated by the somatic nerve, which seems unlikely given the clinical improvements, or the reflex becomes suppressed. Over time, there may be a reconfiguration of the micturition centers in the brain, and as the child learns to void independently, the brain suppresses this reflex, as observed in toilet training. It would be intriguing to conduct functional magnetic resonance imaging (fMRI) of the brain before and after nerve rerouting to observe the effects of stimulating this reflex compared to patients who regain sensation and can void without reflex stimulation. Additionally, it would be interesting to explore the relationships between cutaneous stimulation, rectal activity, improved bladder sensation, and the emergence/disappearance of the skin-bladder reflex.

In conclusion, this pilot trial demonstrated improvements in bladder and bowel function in spina bifida patients following lumbar to sacral nerve rerouting. Future studies should expand on these findings, ensuring patient consent and understanding of potential outcomes, including the risk of permanent foot drop. While further data are necessary to fully comprehend the procedure’s impact, nerve rerouting shows promise in revolutionizing the management of neurogenic bladder in patients.

Kenneth M. PetersOakland University William Beaumont School of Medicine

The Xiao procedure is an effective treatment method for neurogenic bladder in patients

Beaumont Hospital, Royal Oak presents and showcases the complete Xiao procedure process

Results of Bladder Re-Innervation with the Xiao Procedure in SCI Patients

Enhanced Bladder Re-Innervation Techniques: China’s Leading Innovations and Global Perspectives

Bladder Re-Innervation in China:

Significant progress has been made in bladder re-innervation procedures in China, with notable research conducted by Professor Xiao’s team and other major centers. Hou CL’s team at the Second Army Medical University has focused on somatic-autonomic re-innervation since 2008, achieving a 75% success rate in paraplegic patients within 6-12 months post-surgery. Their innovative approach, utilizing the S1 nerve root and new reflex pathways, has shown promising results, especially in cases of atonic bladder post-conus medullaris injury.

Cao XJ’s team at Nanjing Medical University has further refined the Xiao procedure, reducing operation times, enhancing post-surgery regeneration, and minimizing complication rates. Their modifications, such as incorporating Ban acetylcholinesterase antibody-based quartz crystal microbalance for root identification, offer potential advancements in surgical precision and efficiency.

Comparative Analysis with the USA:

In contrast, the USA has reported positive outcomes with the Xiao procedure for treating neurogenic bladder resulting from complete spinal cord injury. However, varying results have been observed, with successful cases in younger patients and challenges in others. A comparison of European and Chinese approaches to neurogenic bladder management has highlighted differing methods, with China’s cost-effective solutions showing promise. The conflict between anticholinergics and bladder re-innervation has led to the establishment of specific criteria for the Xiao procedure to optimize outcomes. Continuous use of anticholinergics may hinder the success of re-establishing neural control of the lower urinary tract, underscoring the importance of tailored approaches for achieving optimal results.

Bladder Re-Innervation in Spina Bifida Patients:

Varied Outcomes of Xiao Procedure in Spina Bifida Patients: Key Considerations

Research conducted by Peters and his colleagues at Beaumont Hospital in the USA focused on a pilot study of the Xiao procedure for spina bifida children with neurogenic bladder. Out of 13 subjects (nine female, median age 8 years), notable outcomes were observed: 3 subjects voided small amounts of 20 cc at baseline, 1 voided 200 cc with a voiding efficiency of 32%, 4 reported normal bowels, and 2 were continent of stool. Over 3 years, renal function remained stable, and the mean maximum cystometric capacity (MCC) increased significantly (p = 0.0135). Among the 10 subjects who returned at 3 years, 8 were treatment responders with voiding efficiency over 50%, and 9 had discontinued anti-muscarinics. The pilot study demonstrated the feasibility and effectiveness of somatic bladder re-innervation by the Xiao procedure in spina bifida patients, enhancing their elimination.

However, a conflicting study by Tuite and colleagues reported a lack of efficacy of the Xiao procedure for bladder control in spina bifida children. In their prospective, randomized, double-blind study involving 20 spina bifida children, none showed improvement in bladder function after 3 years of follow-up. This study faced criticisms regarding its design and methodology, with concerns raised about the variation in neurologic conditions, surgical history, and the discontinuation of CIC and anticholinergics postoperatively.

The inconsistent use of anticholinergic medications and clean intermittent catheterization (CIC) may stem from the reluctance of investigators and clinicians to deviate from the established standard of care in the USA and Europe, which mandates CIC and anticholinergic medications for all patients with neurogenic bladder and urinary retention. The challenges in implementing uniform postoperative care, including the cessation of anticholinergics, highlight the complexities of conducting double-blind trials in this context. Further data collection and detailed reporting on post-operative medication usage are recommended to enhance the understanding of treatment outcomes in these patients.

A few months later, the team published in the American Journal of Urology acknowledging the effectiveness of the surgery. Patients who underwent the Xiao procedure showed significant improvements in bladder capacity, bladder urodynamics tests, and overall quality of life compared to those who did not undergo the Xiao procedure.

Development of the Xiao Procedure by Chinese Doctors

In the early stages of reconstructing the reflex arc, nerve anastomosis techniques involved connecting the L5 and S2 or S3 anterior roots. While this method was safe for spinal cord injury patients, it could lead to foot drop complications in children with myelomeningocele. Professor Hou Chun-Lin‘s research revealed the possibility of using the S1 nerve root for anastomosis, avoiding foot drop issues. Currently, Professor Xiao Chuan-Guo and experts both domestically and internationally use the S1 nerve root for reflex arc reconstruction, primarily through unilateral S1 and single S2 or S3 anterior root anastomosis. Theoretically, bilateral and double nerve anastomosis could enhance urinary dynamics and reduce urinary retention resistance.

Under the guidance of Professors Xiao Chuan-Guo and Hou Chun-Lin, Professor Cao Xiao-Jian‘s team has made improvements to address clinical challenges with the Xiao Procedure. Progress includes precise and effective separation of spinal nerve roots in the dorsal root ganglia, enabling tension-free anastomosis of the S1 and S2 or S3 anterior roots within the extradural vertebral canal. This method has been successfully applied in treating neurogenic bladder, showing enhanced surgical outcomes. Additionally, a new surgical approach aims to balance urinary dynamics and resistance in treating bladder dysfunction post-spinal cord injury by combining the Xiao Procedure with the Brindley Procedure. This method has the potential to significantly improve the treatment outcomes of neurogenic bladder and has been approved for clinical implementation. Furthermore, the development of piezoelectric immunosensors by Professor Cao Xiao-Jian‘s team offers a simple, fast, and accurate method for identifying nerve properties, showing promising results for clinical applications in distinguishing nerve bundle properties.

Invitation to Join Groundbreaking Spina Bifida Surgery in China

Xiao Chuan-Guo’s team invites interested urologists and neurosurgeons to come to China, participate in 10 cases using the Xiao procedure, and follow up with as many post-operative spina bifida children as desired. The procedure is now as effective, safe, reliable, and straightforward as hernia repair in restoring bladder function and enabling voluntary voiding for the majority of spina bifida children and spinal cord injury (SCI) patients. This is provided that the crossover anastomosis is satisfactory, clean intermittent catheterization (CIC) and anticholinergic medications are discontinued from the third month after surgery, and there is no detrusor de-compensation or fibrosis in the bladder.

Apply for This Training