"Skin-CNS-bladder" reflex pathway for micturition after spinal cord injury and its underlying mechanisms

MR. Lateralization of bladder function in normal female canines

This study aimed to identify potential lateralization of bladder function. Electrical stimulation of spinal roots or the pelvic nerve’s anterior vesical branch was performed bilaterally in female dogs. The percent difference between the left and right stimulation-induced increased detrusor pressure was determined. Bladders were considered left or right-sided if differences were greater or less than 25% or 10%. Based on differences of 25%, upon stimulation of spinal roots, bladders were left-sided in 17/44 (38.6%), right-sided in 12/44 (27.2%) and bilateral in 15/44 (34.2%). Using ± 10%, 48% had left side dominance (n = 21/44), 39% had right side dominance (n = 17/44), and 14% were bilateral (n = 6/44). With stimulation of the pelvic nerve’s anterior vesical branch in 19 dogs, bladders were left-sided in 8 (42.1%), right-sided in 6 (31.6%) and bilateral in 5 (26.3%) using 25% differences and left side dominance in 8 (43%), right sided in 7 (37%) and bilateral in 4 (21%) using 10% differences. These data suggest lateralization of innervation of the female dog bladder with left- and right-sided lateralization occurring at similar rates. Lateralization often varied at different spinal cord levels within the same animal.

Management of neurogenic bladder in patients with Parkinson's disease: A systematic review

AIMS

To assess the different treatment methods in management of neurogenic bladder (NGB) in patients with Parkinson's disease (PD).

METHODS

A systematic search was performed in Cochrane library, EMBASE, Proquest, Clinicaltrial.gov, WHO, Google Scholar, MEDLINE via PubMed, Ovid, ongoing trials registers, and conference proceedings in November 11, 2017. All randomized controlled trials (RCTs) or quasi-RCTs comparing any treatment method for management of NGB in patients with PD were included. The titles and abstracts of all identified studies were evaluated independently by two investigators. Once all of the potential related articles were retrieved, each author separately evaluated the full text of each article and the quality of the methodology of the selected studies using the Cochrane appraisal risk of bias checklist and then the data about the patient's outcomes was extracted. We registered the title in Joanna Briggs Institute (JBI) that is available in http://joannabriggs.org/research/registered_titles.aspx.

RESULTS

We included 41 RCTs or quasi-RCTs or three observational study with a total of 1063 patients that evaluated pharmacological, neurosurgical, botulinum toxin, electrical neuromodulation, and behavioral therapy effects on NGB. Among the included studies only solifenacin succinate double-blind, randomized, placebo-controlled study was assessed as low risk of bias, and treatment led to an improvement in urinary incontinence.

CONCLUSIONS

Although several interventions are available for treatment NGB in patients with PD, at present there is little or no evidence that treatment improves patient outcomes in this population. Additional large, well designed, randomized studies with improved methodology and reporting focused on patient-centered outcomes are needed.

Anatomical Feasibility of Extradural Transferring S2 and S3 Ventral Roots to S1 Ventral Root for Restoring Neurogenic Bladder in Spinal Cord Injury

STUDY DESIGN

Anatomic study in six formalin-fixed cadavers.

OBJECTIVE

To determine the anatomical feasibility of transferring the S2 and S3 ventral roots (VRs) to S1 VR as a method for restoring bladder dysfunction in spinal cord injury.

SUMMARY OF BACKGROUND DATA

A large quantity of researches of neuroanastomosis methods have been used for treating the bladder dysfunction in spinal cord injury. However, some limitations retard the development of those studies.

METHODS

In this study, six formalin-fixed cadavers (four males, two females) were dissected. The feasibility of exposing the S1, S2, and S3 extradural nerve roots by the limited laminectomy, isolating the VR and dorsal roots from each extradural nerve root and transferring the S2,S3 VRs to the S1 VR were assessed. The pertinent distances and the nerve cross-sectional areas in each specimen were measured. The morphology of each nerve root was observed by hematoxylin-eosin staining.

RESULTS

The limited laminectomy was performed to expose the S1 to S3 extradural nerve roots. The VRs could be isolated from each extradural nerve root at the location of the dorsal root ganglion and the hematoxylin-eosin staining showed that there were some connective tissues separating the VRs from the corresponding dorsal root ganglion. The S2 and S3 VRs have sufficient lengths to be transferred to S1 VR without grafting. The mean cross-sectional area of the S1 VR was 2.60 ± 0.17 mm, and that was 1.02 ± 0.32 mm and 0.51 ± 0.21 mm of the S2 and S3 VRs, respectively.

CONCLUSION

This study demonstrated that use of the S2 and S3 VRs for extradural transfer to S1 VR for restoring bladder dysfunction is surgically feasible.

LEVEL OF EVIDENCE

5.

Lumbar to sacral root rerouting to restore bladder function in a feline spinal cord injury model: Urodynamic and retrograde nerve tracing results from a pilot study

AIMS

Lumbar to sacral rerouting surgery can potentially allow voiding via a skin-central nervous system-bladder reflex pathway. Here, we assessed if this surgery was effective in treating neurogenic bladder dysfunction/sphincter in felines.

METHODS

Eight cats underwent spinal cord transection (SCT) at thoracic level 10/11. Unilateral L7 to S1 ventral root anastomosis was performed 1 month later in six cats. Two cats served as transection-only controls. Electrical and manual stimulation of L6-S1 dermatomes, and urodynamics were performed at 3, 5, 7, and 9/10 months post transection. At 9/10 months, cats were also evaluated by direct electrophysiological testing of anastomosed roots with urodynamics, then tissue collection and examination of the root anastomosis site and lumbosacral cord ventral horns for cells retrogradely labeled from tracer dye injected 2 weeks earlier into the bladder wall.

RESULTS

At 9/10 months, four of six rerouted cats exhibited increased detrusor pressure provoked by cutaneous stimulation, one cat bilaterally. Two cats presented with a voiding stream after ipsilateral cutaneous stimulation at 7 and 9 months. All six rerouted animals showed regrowth of axons from the L7 ventral horn to the bladder, although some aberrant axonal regrowth was also observed.

CONCLUSION

L7 to S1 ventral root rerouting below the level of SCT showed successful axonal regrowth to the bladder from the L7 spinal cord segment in all rerouted animals, and induced increased detrusor pressure response to cutaneous stimulation in a subset. This feasibility study paves the way for future animal studies for bladder reinnervation.

The feasibility study of extradural nerve anastomosis technique for canine bladder reinnervation after spinal cord injury

OBJECTIVE

Intradural nerve anastomosis for bladder innervation has been demonstrated to be useful. However, its clinical application remains limited because of the complex surgery, its complications and extensive bony destruction. The purpose of the current study was to demonstrate the feasibility of extradural spinal root anastomosis for bladder innervation in canines.

METHODS

Ten beagle dogs were used. The length of the extradural segment of the nerve root, upper nerve root outlet (the point at which it emerges from the spinal dura mater) to S2 (dS2), the S3 (dS3) nerve root outlet distance, and the diameters of the extradural spinal roots were measured. The numbers of nerve fibers from L6 to S3 ventral roots were calculated using immunohistochemical staining.

RESULTS

The extradural spinal roots could be divided into a ventral root (VR) and a dorsal root (DR) before the ganglionic enlargement of the dorsal root, and the extradural motor nerve roots situate ventrally to their corresponding sensory nerve roots. The extradural nerve root lengths of S1 and parts of L7 were longer than the corresponding dS2. The numbers of nerve and motor nerve fibers, and the diameters of extradural nerve roots, were gradually descending from L6 to S3.

CONCLUSION

The S1 VRs and parts of the L7 VRs can be extradurally anastomosed to the S2 nerves without tension. A nerve graft was needed for extradural anastomosis of L6 VRs and parts of L7 VRs to S2 VRs. This study demonstrated the feasibility of extradural spinal nerve anastomosis for treating neurogenic bladder in canines.

Experimental Electrophysiological and Pressure Responses of Urinary Bladder Detrusor to Lumbar to Sacral Nerve Rerouting - An Animal Study with Negative Results

Background/Aims/Objectives: To verify the transfer of evoked potentials through anastomosis of an experimentally created micturition reflex arc and to detect said potentials directly on the detrusor and sphincter of rabbit urinary bladder.

METHODS

During 2013-2015, 17 rabbits were operated upon and measurement followed during reoperation 3-16 months later. Suitable ventral spinal roots were electrophysiologically detected following laminectomy, and a somatic-central nervous system-autonomic micturition reflex arc was created. During reoperation, the ventral root was stimulated above and below the anastomosis, the evoked potentials on the bladder detrusor and sphincter were measured, and intravesical pressure was monitored.

RESULTS

With stimulation above the anastomosis, 9 animals (53%) displayed a urinary bladder detrusor response and 7 (41%) a sphincter response. Four rabbits (24%) had elevated intravesical pressure. During the control stimulation below the anastomosis, we detected a detrusor response in 7 animals (41%), a sphincter response in 5 (29%), and elevated pressure in 4 (24%). Neither induction of micturition nor decrease in external sphincter activity occurred.

CONCLUSIONS

Creation of a somatic-CNS-autonomic reflex arc is technically possible. However reflex activity transferring through the anastomosis is detectable on the detrusor only in some individuals, and is unable to induce a micturition reflex with or without accompanying detrusor-sphincter dyssynergia.

Lack of efficacy of an intradural somatic-to-autonomic nerve anastomosis (Xiao procedure) for bladder control in children with myelomeningocele and lipomyelomeningocele: results of a prospective, randomized, double-blind study

OBJECTIVE Xiao et al. and other investigators have studied an intradural somatic-to-autonomic (e.g., L-5 to S3-4) nerve transfer as a method to create a reflex arc to allow bladder emptying in response to cutaneous stimulation (the Xiao procedure). In previous clinical studies of patients with spinal dysraphism who underwent the Xiao procedure, high success rates (70%-85%) were reported for the establishment of a "skin-CNS-bladder" reflex arc that allows spontaneous, controlled voiding in children with neurogenic bladder dysfunction. However, many of these studies did not use blinded observers, did not have control groups, and/or featured only limited follow-up durations. METHODS A randomized, prospective, double-blind trial was initiated in March 2009, enrolling children with myelomeningocele (MM), lipomyelomeningocele (LMM), and neurogenic bladder dysfunction who were scheduled for spinal cord detethering (DT) for the usual indications. At the time of DT, patients were randomized between 2 arms of the study: half of the patients underwent a standard spinal cord DT procedure alone (DT group) and half underwent DT as well as the Xiao procedure (DT+X group). Patients, families, and study investigators, all of whom were blinded to the surgical details, analyzed the patients' strength, sensory function, mobility, voiding, and urodynamic bladder function before surgery and at regular intervals during the 3-year follow-up. RESULTS Twenty patients were enrolled in the study: 10 underwent only DT and the other 10 underwent DT+X. The addition of the Xiao procedure to spinal cord DT resulted in longer operative times (p = 0.024) and a greater chance of wound infection (p = 0.03). Patients in both treatment arms could intermittently void or dribble small amounts of urine (< 20% total bladder capacity) in response to scratching in dermatomes T-9 through S-2 using a standardized protocol, but the voiding was not reproducible and the volume voided was not clinically useful in any patient. Voiding in response to scratching was not more frequent in patients who underwent DT+X compared with those who underwent only DT. Bladder contractions in response to scratching occurred in both treatment arms at various intervals after surgery, but they were not more reproducible or more frequent in the patients who underwent the Xiao procedure than in the patients who did not. No patient in either treatment arm was continent of urine before, during, or after the study. CONCLUSIONS Patients with MM and LMM who underwent the Xiao procedure during spinal cord DT were no more likely to be able to void, to control their urination, to achieve continence, or to have a demonstrable urodynamic bladder contraction in response to cutaneous stimulation than patients who underwent only spinal cord DT. This study, in the context of disappointing results reported in other recent studies of the Xiao procedure, raises doubts about the clinical applicability of this procedure in humans until further basic science research is performed.

Neural reconstruction methods of restoring bladder function

During the past century, diverse studies have focused on the development of surgical strategies to restore function of a decentralized bladder after spinal cord or spinal root injury via repair of the original roots or by transferring new axonal sources. The techniques included end-to-end sacral root repairs, transfer of roots from other spinal segments to sacral roots, transfer of intercostal nerves to sacral roots, transfer of various somatic nerves to the pelvic or pudendal nerve, direct reinnervation of the detrusor muscle, or creation of an artificial reflex pathway between the skin and the bladder via the central nervous system. All of these surgical techniques have demonstrated specific strengths and limitations. The findings made to date already indicate appropriate patient populations for each procedure, but a comprehensive assessment of the effectiveness of each technique to restore urinary function after bladder decentralization is required to guide future research and potential clinical application.

Challenges for Restoration of Lower Urinary Tract Innervation in Patients with Spinal Cord Injury: A European Single-center Retrospective Study with Long-term Follow-up

Xiao and colleagues in China reported successful restoration of bladder control in patients with spinal cord injury (SCI) by establishing a somatic-autonomic reflex pathway through lumbar-to-sacral ventral root nerve rerouting. We evaluated long-term results in eight patients who underwent this procedure at a German university clinic between 2005 and 2007. The primary outcome was the occurrence of voiding upon stimulation of the skin, with normalization of bladder pressure when filling, as assessed with videourodynamics at each visit. Videourodynamic variables, urinary tract infections, and bladder/stool events recorded in a patient diary were stored in a prospective database and reviewed retrospectively. Intraoperative testing indicated successful nerve rerouting in all eight patients. Duration of follow-up was 71 mo (range: 56-86). No patient reached the primary goal of voluntary voiding with normalization of detrusor pressure at any point during follow-up. No improvements in videourodynamic or diary variables regarding bladder function were observed. In view of the lack of short (12-18 mo) and long-term (71 mo) success in our patients and others, the risks of any surgical procedure using general anesthesia, and potential for unmet expectations to wreak havoc on patient emotional well-being, we cannot recommend this procedure for patients with SCI.

PATIENT SUMMARY

Although the hope was to improve long-term outcomes of spinal cord injury patients, intraspinal nerve rerouting did not improve or normalize bladder function. In view of the lack of success, we cannot recommend this procedure until proven in clinical studies.

Reconstruction of atonic bladder innervation after spinal cord injury: A bladder reflex arc with afferent and efferent pathways

Background Establishing bladder reflex arcs only with the efferent pathway to induce micturition after spinal cord injury (SCI) has been successful. However, the absence of sensory function and micturition desires can lead to serious complications. Objectives To reconstruct a bladder reflex arc with both afferent and efferent pathways to achieve atonic bladder innervation after SCI. Methods A reflex arc was established by microanastomosis of the S2 dorsal root to the peripheral process of the L5 dorsal ganglion and the L5 ventral root to the S2 ventral root. The functions of the reflex arc were evaluated using electrophysiology, wheat germ agglutinin-horseradish peroxidase (WGA-HRP) tracing, and calcitonin gene-related peptide (CGRP) immunocytochemistry analysis. Hind-paw motion was evaluated by CatWalk gait. Results Compound action potentials and compound muscle action potentials were recorded at the right L5 dorsal root following electrical stimulation of right S2 dorsal root. Similar to the control side, these were not significantly different before or after the spinal cord destruction between L6 and S4. WGA-HRP tracing and CGRP immunocytochemistry showed that construction of the afferent and efferent pathways of the bladder reflex arc encouraged axonal regeneration of motor and sensory nerves, which then made contact with the anterior and posterior horns of the spinal cord, ultimately reestablishing axoplasmic transportation. Gait analysis showed that at 3 months following the operation, only the regularity index was significantly different as compared with 1 day before the operation, other parameters showing no difference. Conclusion Bladder reflex arc with the afferent and efferent pathways reconstructs the micturition function without great influence on the motion of leg.

Bladder reinnervation using a primarily motor donor nerve (femoral nerve branches) is functionally superior to using a primarily sensory donor nerve (genitofemoral nerve)

PURPOSE

We determined whether transfer of a primarily motor nerve (femoral) to the anterior vesicle branch of the pelvic nerve would allow for more effective bladder reinnervation than transfer of a primarily sensory nerve (genitofemoral).

MATERIALS AND METHODS

A total of 41 female mongrel dogs underwent bladder decentralization and then bilateral nerve transfer, or served as sham operated or unoperated controls. Decentralization was achieved by bilateral transection of all sacral roots that induced bladder contraction upon electrical stimulation. Retrograde neuronal labeling dye was injected in the bladder 3 weeks before sacrifice.

RESULTS

Increased detrusor pressure after direct stimulation of the transferred nerve, lumbar spinal cord or spinal root was observed in 12 of 17 dogs with genitofemoral nerve transfer and in 9 of 10 with femoral nerve transfer (mean ± SEM 7.6 ± 1.4 and 11.7 ± 3.1 cm H2O, respectively). Mean detrusor pressure after direct electrical stimulation of transferred femoral nerves was statistically significantly greater than after stimulation of transferred genitofemoral nerves. Retrograde labeled neurons from the bladder observed in upper lumbar cord segments after genitofemoral and femoral nerve transfer confirmed bladder reinnervation, as did labeled axons at the nerve transfer site.

CONCLUSIONS

While transfer of a mixed sensory and motor nerve (genitofemoral) or a primarily motor nerve (femoral) can reinnervate the bladder, using the primarily motor nerve provided greater return of nerve evoked detrusor contraction. This surgical approach may be useful to achieve bladder emptying in patients with lower motor spinal cord injury.

US Pilot Study of Lumbar to Sacral Nerve Rerouting to Restore Voiding and Bowel Function in Spina Bifida: 3-Year Experience

Objective. To report our experience with creating a skin-central nervous system-bladder reflex arc with intradural lumbar to sacral motor root microanastomosis to restore bladder/bowel function in spina bifida patients. Methods. Urinary/bowel changes from baseline to three years were evaluated with questionnaires, voiding diaries, urodynamics (UDS), and renal function studies. Treatment response was defined as CIC ≤ once/day with stable renal function, voiding efficiency > 50%, and no worsening of motor function. Results. Of 13 subjects (9 female, median age 8 years), 3 voided small amounts at baseline, one voided 200 cc (voiding efficiency 32%), 4/13 reported normal bowels, and 2/13 were continent of stool. Postoperatively, all had transient lower extremity weakness; one developed permanent foot drop. Over three years, renal function remained stable and mean maximum cystometric capacity (MCC) increased (P = 0.0135). In the 10 that returned at 3 years, 7 were treatment responders and 9 had discontinued antimuscarinics, but most still leaked urine. Only 2/8 with baseline neurogenic detrusor overactivity (NDO) still had NDO, all 3 with compliance <10 mL/cm H₂O had normalized, 7/10 considered their bowels normal, 5/10 were continent of stool, and 8/10 would undergo the procedure again. Conclusion. Lumbar to sacral nerve rerouting can improve elimination in spina bifida patients. This trial is registered with ClinicalTrials.gov NCT00378664.

Extradural nerve anastomosis technique for bladder reinnervation in spinal cord injury: anatomical feasibility study in human cadavers

STUDY DESIGN

An anatomic study of extradural spinal root in 9 embalmed cadavers.

OBJECTIVE

To ascertain the anatomical parameters of the extradural spinal root and to demonstrate the feasibility of spinal root anastomoses without opening the spinal dura mater.

SUMMARY OF BACKGROUND DATA

Intradural anastomosis of the spinal root has made breakthrough progress in treating neurogenic bladder in spinal cord injury. However, because of the complex surgical procedures and extensive bony destruction, its clinical use is not widely promoted.

METHODS

Nine formalin-fixed cadavers were used. The distance between the nerve root outlet and ganglion center, the neighboring nerve root-outlet distance, and the gross anatomy of the extradural spinal root were measured with a surgical microscope. The number of nerve fibers from the T7 to S4 ventral roots (VRs) was calculated by immunohistochemical staining.

RESULTS

The longest and shortest lengths of the extradural spinal root were observed at the S4 and T7 levels, with average values of 33.29 and 6.06 mm, respectively. The longest distance between the adjacent nerve root outlets was observed at L1-L2 (mean, 29.16 mm), and shortest at S3-S4 (mean, 11.79 mm). After leaving the dural sac, the spinal root descends in the spinal canal until reaching the corresponding intervertebral foramina, and the motor nerve roots still lie ventrally to the sensory nerve roots. The largest and smallest numbers of nerve fibers were observed at the L3 and S4 levels (mean, 9169 and 1356, respectively).

CONCLUSION

The dorsal roots and VRs can both be successfully harvested and identified outside the dural sac. The S1 VR can be anastomosed to the S2 VR extradurally without nerve grafts. For extradural neuroanastomosis of the thoracic VRs to the S2 VR, a nerve graft is required. In addition, there are a sufficient number of nerve fibers for functional bladder recovery at the T7-T12 and S1 levels. This study supports the feasibility of extradural spinal root anastomosis as a modified surgical method for treating neurogenic bladder.

LEVEL OF EVIDENCE

N/A.

Attempted bladder reinnervation and creation of a scratch reflex for bladder emptying through a somatic-to-autonomic intradural anastomosis

An intradural somatic-to-autonomic anastomosis, or Xiao procedure, has been described to create a "skin-CNS-bladder" reflex that improves bladder and bowel function in patients with neurogenic bladder and bowel dysfunction. The authors present their experience with a 10-year-old boy with chronic neurogenic bladder and bowel dysfunction related to spinal cord injury who underwent the Xiao procedure. After undergoing a left L-5 ventral root to left S2-3 intradural anastomosis, the patient reported that his bladder and bowel dysfunction improved between 6 and 12 months. Two years after the procedure, however, he reported that there was no change in his bladder or bowel dysfunction as compared with his condition prior to the procedure. Frequent, systematic multidisciplinary evaluations produced conflicting data. Electrophysiological and histological evaluation of the previously performed anastomosis during surgical reexploration 3 years after the Xiao procedure revealed that the anastomosis was in anatomical continuity but neuroma formation had prevented reinnervation. Nerve action potentials were not demonstrable across the anastomosis, and stimulation of the nerve above and below the anastomosis created no bladder or perineal contractions. This is the first clinical report on the outcome of the Xiao procedure in a child with spinal cord injury outside of China. It is impossible to draw broad conclusions about the efficacy of the procedure based on a single patient with no demonstrable benefit. However, future studies should carefully interpret transient improvements in bladder function, urodynamic findings, and the patient's ability to void in response to scratching after the Xiao procedure. The authors' experience with the featured patient, in whom reinnervation could not be demonstrated, suggests that such changes could be related to factors other than the establishment of a skin-CNS-bladder reflex as a result of a somatic-to-autonomic anastomosis.

Anatomical feasibility of performing a nerve transfer from the femoral branch to bilateral pelvic nerves in a cadaver: a potential method to restore bladder function following proximal spinal cord injury

OBJECT

Nerve transfers are an effective means of restoring control to paralyzed somatic muscle groups and have recently been shown to be effective in denervated detrusor muscle in a canine model. A cadaveric study was performed to examine the anatomical feasibility of transferring femoral muscular nerve branches to vesical branches of the pelvic nerve as a method of potentially restoring innervation to control the detrusor muscle in humans.

METHODS

Twenty cadavers were dissected bilaterally to expose pelvic and femoral muscular nerve branches. Ease of access and ability to transfer the nerves were assessed, as were nerve cross-sectional areas.

RESULTS

The pelvic nerve was accessed at the base of the bladder, inferior to the ureter, and accompanied by inferior vesical vessels. Muscular branches of the femoral nerve to the vastus medialis and intermedius muscles (L-3 and L-4 origins) were followed distally for 17.4 ± 0.8 cm. Two muscle branches were split from the femoral nerve trunk, and tunneled inferior to the inguinal ligament. One branch was moved medially toward the base of the bladder and linked to the ipsilateral pelvic nerve. The second branch was tunneled superior to the bladder and linked to the contralateral pelvic nerve. The cross-sectional area of the pelvic nerve vesical branch was 2.60 ± 0.169 mm(2) (mean ± SEM), and the femoral nerve branch at the suggested transection site was 4.40 ± 0.41 mm2.

CONCLUSIONS

Use of femoral nerve muscular branches from the vastus medialis and intermedius muscles for heterotopic nerve transfer of bilateral pelvic nerves is surgically feasible, based on anatomical location and cross-sectional areas.

Hypothesis of peripheral nerve regeneration induced by terminal effectors

Peripheral nerve injury (PNI) is a common trauma in clinical practice. A number of techniques to deal with PNI repair have been designed in clinics. From these methods for nerve repairing shown to be effective in clinics, as well as related experiments, we formulated a hypothesis that PNI regeneration and functional repair are induced by terminal effectors. Regeneration of peripheral nerves is the process whereby the nerve fibers regenerated by the induction of terminal effectors establish connections with effector organs and induce the spinal cord and upper centers to recognize effector organs and to re-model them for effective innervations. The hypothesis has two major components: (1) after surgical repairing of the injured nerves, the functional localization of regenerated nerves is determined by the connected effector organs and (2) the upper nervous system enables structural remodeling and functional changes according to the functions of the effector organs.

Transfer of normal S1 nerve root to reinnervate atonic bladder due to conus medullaris injury

INTRODUCTION

Neurogenic bladder dysfunction after spinal cord injury (SCI) is a major medical and social problem. In this study we assessed the effectiveness of neurogenic bladder reinnervation in patients with SCI using a normal S1 nerve root.

METHODS

Nine patients with bladder dysfunction caused by injury to the low conus medullaris (S2-S5) underwent a novel surgical procedure in which the unilateral proximal end of the S1 ventral root (VR) was anastomosed to the distal end of the S2 and S3 VRs.

RESULTS

Seven patients regained satisfactory bladder control within 8-12 months after VR microanastomosis. The average residual urine volume decreased from 186.0 ± 35.0 ml to 43.0 ± 10.0 ml, and no urinary infections occurred.

CONCLUSIONS

These results suggest the effectiveness of bladder innervation by S1 nerve transfer, which could provide a new approach for the reconstruction of atonic bladder function caused by low conus medullaris injuries.

Anatomical feasibility of performing intercostal and ilioinguinal nerve to pelvic nerve transfer: a possible technique to restore lower urinary tract innervation

OBJECT

Nerve transfers are effective for restoring control to paralyzed somatic muscle groups and, recently, even to denervated detrusor muscle in a canine model. A pilot project was performed in cadavers to examine the feasibility of transferring somatic nerves to vesical branches of the pelvic nerve as a method for potentially restoring innervation to control the detrusor muscle in humans.

METHODS

Eleven cadavers were dissected bilaterally to expose intercostal, ilioinguinal, and iliohypogastric nerves, along with vesical branches of the pelvic nerve. Ease of access and ability to transfer the former 3 nerves to the pelvic vesical nerves were assessed, as were nerve cross-sectional areas.

RESULTS

The pelvic vesical nerves were accessed at the base of the bladder, inferior to the ureter and accompanied by inferior vesical vessels. The T-11 and T-12 intercostal nerves were too short for transfer to the pelvic vesical nerves without grafting. Ilioinguinal and iliohypogastric nerves (L-1 origin) were identified retroperitoneally and, with full dissection, were easily transferred to the pelvic vesical nerves intraabdominally. The mean cross-sectional area of the dominant pelvic vesical branch was 2.60 ± 0.169 mm(2); ilioinguinal and iliohypogastric branches at the suggested transection site were 2.38 ± 0.32 mm(2) (the means are expressed ± SEM).

CONCLUSIONS

Use of the ilioinguinal or iliohypogastric nerves for heterotopic transfer to pelvic vesical nerves is surgically feasible, based on anatomical location and cross-sectional areas.

Re-innervation of the bladder through end-to-side neurorrhaphy of autonomic nerve and somatic nerve in rats

End-to-side neurorrhaphy is widely used in the peripheral nervous system for nerve repair; however, the application of this technique has been limited to somatic nerves. The feasibility of nerve regeneration through end-to-side neurorrhaphy between autonomic and somatic nerves with different characteristics in the peripheral nervous system is still undetermined. In this study, rats were divided into three groups for different treatments (n=10 per group). In the end-to-side neurorrhaphy group, left L6 and S1 were transected in the dura, and the distal stump of L6 ventral root was sutured to the lateral face of L4 ventral root through end-to-side coaptation. In the no repair group, the rats did not undergo neurorrhaphy. In the control group, the left L6 dorsal root and S1 roots were transected, respectively, but the L6 ventral root was kept intact. After 16 weeks, the origin and mechanism of nerve regeneration was evaluated by retrograde double labeling technique as well as histological examination and intravesical pressure measurement. Retrograde double labeling indicated that the reconstructed reflex pathway was successfully established and the primary regeneration mechanism involved axon collateral sprouting. Morphological examination and intravesical pressure measurement indicated prominent nerve regeneration and successful re-innervation of the bladder in the neurorrhaphy group, compared with the "no repair" group (p<0.05). No significant changes were observed in the histology of the donor nerve and the bilateral extensor digitorum longus muscles in the neurorrhaphy group. Nerve regeneration may be achievable for nerve repair through end-to-side neurorrhaphy between autonomic and somatic nerves without apparent impairment of donor somatic nerve.

The longitudinal spinal cord injury: lessons from intraspinal plexus, cauda equina and medullary conus lesions

Spinal nerve root avulsion injury interrupts the transverse segmental spinal cord nerve fibers. There is degeneration of sensory, motor, and autonomic axons, loss of synapses, deterioration of local segmental connections, nerve cell death, and reactions among non neuronal cells with central nerve system (CNS) scar formation, i.e., a cascade of events similar to those known to occur in any injury to the spinal cord. This is the longitudinal spinal cord injury (SCI). For function to be restored, nerve cells must survive and there must be regrowth of new nerve fibers along a trajectory consisting of CNS growth-inhibitory tissue in the spinal cord as well as peripheral nervous system (PNS) growth-promoting tissue in nerves. Basic science results have been translated into a successful surgical strategy to treat root avulsion injuries in man. In humans, this technique is currently the most promising treatment of any spinal cord injury, with return of useful muscle function together with pain alleviation. Experimental studies have also identified potential candidates for adjunctive therapies that, together with surgical replantation of avulsed roots after brachial plexus and cauda equina injuries, can restore not only motor but also autonomic and sensory trajectories to augment the recovery of neurological function. This is the first example of a spinal cord lesion that can be treated surgically, leading to restoration of somatic and autonomic activity and alleviation of pain.

Micturition reflex arc reconstruction including sensory and motor nerves after spinal cord injury: urodynamic and electrophysiological responses

OBJECTIVE

To evaluate artificial reflex arcs for micturition using urodynamics and electrophysiological recordings.

DESIGN

Sixteen beagles were equally and randomly divided into two groups.

METHODS

In group A, anastomosis of the proximal end of the left L7 ventral root (VR) and distal end of the left S2 VR was performed, as well as anastomosis of the L7 dorsal root (DR) and S2 DR to reconstruct the sensory and the motor function of the bladder. In group B the proximal end of the left L7 VR and the distal end of the left S2 VR were anastomosed, while the left L7 DR was kept intact to reconstruct the motor function of the bladder. Outcome measures included electrophysiological testing and the urodynamic measures. In addition, we also monitored urinary infection rates.

RESULTS

Stimulation to the left S2 DR in groups A and B both elevated the bladder pressure before and after the spinal lower motor neuron lesion. Single stimulation of the two groups both elicited evoked action potentials. Urinary infections occurred in group A (three occurrences) and in group B (eight occurrences) during the 3 months after the spinal lower motor neuron lesion.

CONCLUSION

Data showed that both reconstructive methods could induce bladder micturition and evoked action potentials. However, in group A the micturition response was better and the urinary infection rates were lower after the spinal lower motor neuron lesion. Thus, the artificial physiological reflex arc reconstruction method used in group A, with sensory input above the lesion, might provide a better alternative in clinical practice.

Feasibility of a femoral nerve motor branch for transfer to the pudendal nerve for restoring continence: a cadaveric study

OBJECT

Nerve transfers are an effective means of restoring control to paralyzed somatic muscle groups and, recently, even denervated detrusor muscle. The authors performed a cadaveric pilot project to examine the feasibility of restoring control to the urethral and anal sphincters using a femoral motor nerve branch to reinnervate the pudendal nerve through a perineal approach.

METHODS

Eleven cadavers were dissected bilaterally to expose the pudendal and femoral nerve branches. Pertinent landmarks and distances that could be used to locate these nerves were assessed and measured, as were nerve cross-sectional areas.

RESULTS

A long motor branch of the femoral nerve was followed into the distal vastus medialis muscle for a distance of 17.4 ± 0.8 cm, split off from the main femoral nerve trunk, and transferred medially and superiorly to the pudendal nerve in the Alcock canal, a distance of 13.7 ± 0.71 cm. This was performed via a perineal approach. The cross-sectional area of the pudendal nerve was 5.64 ± 0.49 mm(2), and the femoral nerve motor branch at the suggested transection site was 4.40 ± 0.41 mm(2).

CONCLUSIONS

The use of a femoral nerve motor branch to the vastus medialis muscle for heterotopic nerve transfer to the pudendal nerve is surgically feasible, based on anatomical location and cross-sectional areas.

[Bladder reinnervation with creation of a "somato-autonomic" reflex pathway in spinal cord injured or spina bifida, a new way for treatment?]

CONTEXT

The restoration of physiological micturition is a major objective for patients presenting a medullary injury, which is not possible with current treatment. Several recent studies have purposed some techniques for bladder reinnervation. Their purpose was to begin a voluntary micturition by the stimulation of an artificial reflex arc created by the anastomosis of a somatic root with a root innervating the bladder.

MATERIALS AND METHODS

We searched on Medline and Cochrane for articles in English. The keywords used were: bladder reinnervation, spinal cord injury neurogenic bladder, reflex pathway for micturition.

RESULTS

These studies reported a variable efficacy as high as 85% of the treated patients. These patients could begin micturition voluntarily, associated with a significant improvement observed in their postoperative urodynamic evaluation. In fact, an improvement of the detrusor external sphincter dyssynergia and/or bladder overactivity was reported, and the patients presented a better quality of life by the control of their micturition associated with an improvement in continence with no need for intermittent catheterisation. However, these results were variable from one study to the other, and certain results seem difficult to explain notably concerning the abolition of bladder overactivity and the improvement of the detrusor external sphincter dyssynergia.

CONCLUSION

Further experimental studies are still required, notably with animals to confirm the encouraging results of these initial studies, and to better understand the mechanism before possible routine patient use.

Innervation of parasympathetic postganglionic neurons and bladder detrusor muscle directly after sacral root transection and repair using nerve transfer

AIMS

This is a continuation of studies examining the effectiveness of root repairs and nerve transfers for bladder reinnervation. Our previous retrograde fluorogold tracing studies from the bladder to the spinal cord found regrowth of axons from the spinal cord through the nerve repair site to the bladder which was confirmed electrophysiologically [Ruggieri et al. J Neurotrauma 25:214–24, 2006]. The current study determines whether the pattern of axonal regrowth from the repaired nerves or roots to the bladder is different between the surgical reanastomosis methods.

METHODS

The canine bladder was denervated by transection of all nerve roots from the sacral spinal cord mediating bladder contraction. Reinnervation surgeries included end-on-end repair of transected sacral ventral roots, transfer of coccygeal to sacral ventral roots(CGNT),or transfer of genitofemoral to pelvic nerves(GFNT).

RESULTS

Postmortem dialkylcarbocyaninedye tracing with Neurotrace DiI from the distal pelvic nerve to the bladder wall, combined with PGP9.5 neuronal immunohistochemistry, demonstrated innervation by DiI-labeled axons of only parasympathetic postganglionic intramural ganglia in normal controls and sham operated controls, but reinnervation of both intramural ganglia and detrusor muscle directly after repair of sacral ventral roots. GF NT and CG NT also resulted in reinnervation of both intramural ganglia and detrusor muscle, although to a lesser extent than repaired roots.

CONCLUSIONS

Bladder reinnervation with either the same nerve (orthotopic reinnervation) or with either a primarily somatic nerve (coccygeal) or a primarily sensory nerve (genitofemoral) results in reinnervation of both intramural ganglia as well as direct innervation of detrusor muscle.

Reinnervation of atonic bladder after conus medullaris injury using a modified nerve crossover technique in canines

BACKGROUND

Neurogenic bladder represents a major cause of morbidity in patients with spinal cord injuries (SCI). Herein, we evaluated a novel reconstructive surgical technique designed to restore afferent and efferent nerve function in atonic bladder caused by conus medullaris injury.

MATERIALS AND METHODS

A new reflex pathway was established by extradural transfer of the left L5 ventral root (VR) to the left S2 VR root together with extradural postganglionic spinal nerve transfer of the L5 dorsal root (DR) to the S2 DR with a nerve graft in a canine model. The corresponding nerves on the right side were kept intact and served as a control. After the new reflex pathway was reestablished, the early function of the reflex arc was evaluated by electrophysiologic study, intravesical pressure, and histologic examination.

RESULTS

Action potential (AP) curves were recorded with single focal stimulation of the left S2 DR before and after the spinal cord was destroyed horizontally between the L6 and S3 levels. Bladder contraction was successfully initiated by trains of stimuli targeting the left L5-S2 DR anastomosis. Achievable bladder pressures and the amplitude of bladder smooth muscle complex action potentials were unchanged before and after induced paraplegia and were comparable to those of the control. Prominent axonal sprouting was observed in the distal region of the nerve graft.

CONCLUSION

Both afferent and efferent nerve pathways in the atonic bladder were reconstructed by suprasacral motor-to-motor and sensory-to-sensory extradural nerve transfer in canines. Taken together, these findings suggest a new potential clinical approach for restoring bladder function in individuals with paraplegia.

Outcomes of lumbar to sacral nerve rerouting for spina bifida

PURPOSE

Restoring bladder and bowel function in spina bifida by creation of a skin-central nervous system-bladder reflex arc via lumbar to sacral nerve rerouting has a reported success rate of 87% in China. We report 1-year results of the first North American trial on nerve rerouting.

MATERIALS AND METHODS

Nine subjects were enrolled in the study. Intradural lumbar to sacral nerve rerouting was performed. Subjects underwent urodynamic testing with stimulation of the cutaneous dermatome and careful neurological followup. Adverse events were closely monitored along with changes in bowel and bladder function.

RESULTS

At 1 year 7 patients (78%) had a reproducible increase in bladder pressure with stimulation of the dermatome. Two patients were able to stop catheterization and all safely stopped antimuscarinics. No patient achieved complete urinary continence. The majority of subjects reported improved bowel function. One patient was continent of stool at baseline and 4 were continent at 1 year. Of the patients 89% had variable weakness of lower extremity muscle groups at 1 month. One child had persistent foot drop and the remainder returned to baseline by 12 months.

CONCLUSIONS

At 1 year a novel reflex arc with stimulation of the appropriate dermatome was seen in the majority of subjects. Improvements in voiding and bowel function were noted. Lower extremity weakness was mostly self-limited, except in 1 subject with a persistent foot drop. More patients and longer followup are needed to assess the risk/benefit ratio of this novel procedure.

Clinical study of reconstructed bladder innervation below the level of spinal cord injury to produce urination by Achilles tendon–to-bladder reflex contractions

Object

Neurogenic bladder dysfunction following spinal cord injury (SCI) is a major medical and social problem for which there is no ideal treatment strategy. In the present study, the authors analyze the effectiveness of neurogenic bladder reinnervation in patients with SCIs by using Achilles tendon reflexes below the paraplegic level.

Methods

Spinal root anastomoses were performed in 12 paraplegic patients with hyperreflexic neurogenic bladder and detrusor external sphincter dyssynergia (DESD) caused by complete suprasacral SCI, in an attempt to reinnervate the bladder. The surgery anastomosed the unilateral proximal end of the S-1 ventral root and the distal end of the S-2 and/or S-3 ventral roots to build the Achilles tendon–to-bladder reflex, while the S-1 dorsal root was kept intact as the trigger for micturition after axonal regeneration. All patients underwent urodynamic evaluation before surgery and at follow-up.

Results

The mean follow-up duration was 3 years. Of the 12 patients, 9 (75%) regained satisfactory bladder control within 6 to 12 months after ventral root microanastomosis. In these 9 patients, urodynamic studies revealed a change from detrusor hyperreflexia with DESD and high detrusor pressure to almost normal storage and synergic voiding without DESD. The average bladder capacity increased from 258 ± 33 ml to 350 ± 49 ml, residual urine decreased from 214 ± 36 ml to 45 ± 11 ml, and urinary infections were not observed. Patients with impaired renal function experienced a full recovery. Three patients failed to show any improvement after the operation.

Conclusions

These results suggest the effectiveness of bladder innervation below the level of SCI to produce urination by Achilles tendon–to-bladder reflex contractions, and might therefore provide a new clinical approach to reconstructing spasmodic bladder urination function.

Reconstruction of reflex pathways to the atonic bladder after conus medullaris injury: preliminary clinical results

Neurogenic bladder dysfunction following spinal cord injury is a major medical and social problem for which there is no ideal treatment strategy. In this study, spinal root anastomoses were performed in 10 paraplegic patients with traumatic lesions of the conus medullaris, in an attempt to reinnervate the paralyzed bladder. For the operation, the functional T11 ventral root (VR) above the lesion was transected and anastomosed to the S2 ventral roots unilaterally through a nerve graft. The T11 dorsal root was left intact as the trigger for micturition after axonal regeneration. All patients underwent urodynamic evaluation before surgery and at follow-up. The mean follow-up duration was 2 years. Of the 10 patients, 7 (70%) regained satisfactory bladder control within 18-24 months after VR microanastomosis. In these seven patients, the average bladder capacity decreased from 508 +/- 83 (mean +/- SD) to 370 +/- 59 ml, residual urine decreased from 477 +/- 98 to 35 +/- 11 ml, and urinary infections were not observed. Patients with impaired renal function experienced a full recovery. Three patients failed to show any improvement after the operation. These results suggest that a restitutive process occurs in the bladder following reinnervation from new T11 VR connections to the bladder nerves. Spinal cord lesions that may benefit from such a nerve crossover surgery are those located at the conus, whereby a functional suprasacral nerve can be connected to the sacral roots to bypass the injury in an attempt to restore central connections to the bladder.

Morphological changes of cholinergic nerve fibers in the urinary bladder after establishment of artificial somatic-autonomic reflex arc in rats

OBJECTIVE

To establish an artificial somatic-autonomic reflex arc in rats and observe the following distributive changes of neural fibers in the bladder.

METHODS

Adult Sprague-Dawley rats were randomly divided into three groups: control group, spinal cord injury (SCI) group, and reinnervation group. DiI retrograde tracing was used to verify establishment of the model and to investigate the transport function of the regenerated efferent axons in the new reflex arc. Choline acetyltransferase (ChAT) in the DiI-labeled neurons was detected by immunohistochemistry. Distribution of neural fibers in the bladder was observed by acetylcholine esterase staining.

RESULTS

DiI-labeled neurons distributed mainly in the left ventral horn from L3 to L5, and some of them were also ChAT-positive. The neural fibers in the bladder detrusor reduced remarkably in the SCI group compared with the control (P < 0.05). After establishment of the somatic-autonomic reflex arc in the reinnervation group, the number of ipsilateral fibers in the bladder increased markedly compared with the SCI group (P < 0.05), though still much less than that in the control (P < 0.05).

CONCLUSION

The efferent branches of the somatic nerves may grow and replace the parasympathetic preganglionic axons through axonal regeneration. Acetylcholine is still the major neurotransmitter of the new reflex arc. The controllability of detrusor may be promoted when it is reinnervated by the pelvic ganglia efferent somatic motor fibers from the postganglionic axons.

Selection of the sacral nerve posterior roots to establish skin-CNS-bladder reflex pathway: an experimental study in rats

The purpose of this study was to explore the innervations of different sacral nerve posterior roots to bladder, and to provide evidence for further study of skin-CNS-bladder reflex pathway in the spinal cord injury patient. Spinal cord injury was produced in 10 rats. The bilateral spinal posterior roots of S1-S4 were electrically stimulated, and the bladder plexus action, bladder smooth muscle complex action potential, and intravesical pressure were examined and measured. The results showed that all the sacral nerve posterior roots were involved in innervations of bladder in rats. Among them, the S2 sacral nerve is the dominant nerve in innervations of bladder, followed by S1, S3, and S4 sacral nerve posterior roots. This study has provided valuable information for selection of sacral nerve posterior root for further study of the artificial bladder reflex arc for improving the micturition function in spinal cord injury patients.

Functional reinnervation of the rat lower urinary tract after cauda equina injury and repair

Conus medullaris and/or cauda equina forms of spinal cord injury commonly result in a permanent loss of bladder function. Here, we developed a cauda equina injury and repair rodent model to investigate whether surgical implantation of avulsed lumbosacral ventral roots into the spinal cord can promote functional recovery of the lower urinary tract. Adult female rats underwent sham surgery (n = 6), bilateral L5-S2 ventral root avulsion (VRA) injury (n = 5), or bilateral L5-S2 VRA followed by an acute implantation of the avulsed L6 and S1 ventral roots into the conus medullaris (n = 6). At 12 weeks after operation, the avulsed group demonstrated urinary retention, absence of bladder contractions and external urethral sphincter (EUS) electromyographic (EMG) activation during urodynamic recordings, increased bladder size, and retrograde death of autonomic and motoneurons in the spinal cord. In contrast, the implanted group showed reduced urinary retention, return of reflexive bladder voiding contractions coincident with EUS EMG activation, anatomical reinnervation of the EUS demonstrated by retrograde neuronal labeling, normalization of bladder size, and a significant neuroprotection of both autonomic and motoneurons. In addition, a positive correlation between motoneuronal survival and voiding efficiency was observed in the implanted group. Our results show that implantation of avulsed lumbosacral ventral roots into the spinal cord promotes reinnervation of the urinary tract and return of functional micturition reflexes, suggesting that this surgical repair strategy may also be of clinical interest after conus medullaris and cauda equina injuries.

Novel repair strategies to restore bladder function following cauda equina/conus medullaris injuries

Trauma to the thoracolumbar junction or lumbosacral spine may result in a conus medullaris or cauda equina syndrome. In both conditions, symptoms typically include paraparesis or paraplegia, sensory impairment, pain, as well as bladder, bowel, and sexual dysfunctions. We present in this review a series of neural repair strategies that have been developed to address the unique features and challenges of subjects with a conus medullaris or cauda equina syndrome. We address, in particular, neural repair strategies that may have a translational research potential to restore bladder function. Recent animal injury models have suggested that a progressive retrograde death of both autonomic and motor neurons may contribute to the neurological deficits in subjects with conus medullaris and cauda equina injuries. For subjects with acute injuries, we present novel strategies to promote neuroprotection, axonal regeneration, and functional reinnervation of the lower urinary tract. For subjects with chronic injuries, we discuss new approaches to replace lost autonomic and motor neurons. A brief discussion on a variety of outcome measures that may be suitable to evaluate the function of the lower urinary tract in rodent neural repair models is also provided.

Reinnervation for neurogenic bladder: historic review and introduction of a somatic-autonomic reflex pathway procedure for patients with spinal cord injury or spina bifida

Neurogenic bladder caused by SCI or spina bifida is a major problem. Research in restoring functional micturition has mainly focused on electrical stimulation for many decades with good progress, but it is still not the definitive solution for majority of the SCI patients. An alternative approach has been to investigate restoring innervation to the lower urinary tract after spinal SCI. Different animal and clinical studies were reviewed historically in this article, focused on mainly cross over nerve surgery for reinnervation of the bladder. An artificial somatic-autonomic reflex pathway procedure and its mechanisms were introduced. Clinical application and the satisfactory results of the new procedure were reviewed in details in restoring voluntary bladder control in patients with SCI or spina bifida.

Willentlich steuerbare Miktion durch intradurale Nervenanastomose

INTRODUCTION

One of the major challenges in neuro-urology is the restoration of voluntary voiding in a patient after spinal cord injury (SCI).

ANIMAL EXPERIMENTS

The earliest reports on reconstruction of urinary bladder function by bridging nerve roots from above the SCI to the below this level were published by Carlsson and Sundin 1968. In another approach, a possible reflex pathway below the SCI to reinitiate voluntary voiding was investigated. The result was a modified somatic reflex arc rostral to the sacral spinal micturition center.

FUTURE RESEARCH

Medical reports in numerous publications are still very enthusiastic about the possibility of cell or gene therapy. Such results report the successful bridging of small nerve gaps. The latest approach is the intravenous application of stem cells to aid the recovery of the SCI.

CLINICAL APPROACH

The first reports on attempts to reconstruct the nervous pathways to the bladder in patients were published 1967. In two cases, a nerve anastomosis from Th(12) (the lowest intact segment) to S(2+3), bilaterally to the SCI, allowed spontaneous micturition after 8-12 months with reported sensitivity at the base of the penis. With a modification in surgical technique, another group reported a success rate of 100% using the anastomosis of intercostal nerves Th(11+12) to sacral roots S(2+3) to establish a reflex voiding and, in 72% of patients, reappearance of the bulbocavernous and cremaster reflexes. Xiao et al. published, with a 3 year follow-up, the creation of a micturition reflex through anastomosing the ventral roots of L(5) to S(2/3) in complete SCI patients with a 67% success rate a year after surgery.

CONCLUSION

There is still a great deal of work required before cell therapy becomes a therapeutic option. Today, the published data strongly suggest that it is possible to treat first line urinary bladder dysfunctions in SCI or spina bifida patients. Before one of these techniques becomes widely used, it should be proven effective in specialized institutions, such as the Department of Urology in collaboration with the Department of Neurosurgery at the University of Tuebingen, Germany.

An artificial somatic-autonomic reflex pathway procedure for bladder control in children with spina bifida

PURPOSE

Neurogenic bladder is a major problem for children with spina bifida. Despite rigorous pharmacological and surgical treatment, incontinence, urinary tract infections and upper tract deterioration remain problematic. We have previously demonstrated the ability to establish surgically a skin-central nervous system-bladder reflex pathway in patients with spinal cord injury with restoration of bladder storage and emptying. We report our experience with this procedure in 20 children with spina bifida.

MATERIALS AND METHODS

All children with spina bifida and neurogenic bladder underwent limited laminectomy and a lumbar ventral root (VR) to S3 VR microanastomosis. The L5 dorsal root was left intact as the afferent branch of the somatic-autonomic reflex pathway after axonal regeneration. All patients underwent urodynamic evaluation before and after surgery.

RESULTS

Preoperative urodynamic studies revealed 2 types of bladder dysfunction- areflexic bladder (14 patients) and hyperreflexic bladder with detrusor external sphincter dyssynergia (6). All children were incontinent. Of the 20 patients 17 gained satisfactory bladder control and continence within 8 to 12 months after VR microanastomosis. Of the 14 patients with areflexic bladder 12 (86%) showed improvement. In these cases bladder capacity increased from 117.28 to 208.71 ml, and mean maximum detrusor pressure increased from 18.35 to 32.57 cm H2O. Five of the 6 patients with hyperreflexic bladder demonstrated improvement, with resolution of incontinence. Urodynamic studies in these cases revealed a change from detrusor hyperreflexia with detrusor external sphincter dyssynergia and high detrusor pressure to nearly normal storage and synergic voiding. In these cases mean bladder capacity increased from 94.33 to 177.83 ml, and post-void residual urine decreased from 70.17 to 23.67 ml. Overall, 3 patients failed to exhibit any improvement.

CONCLUSIONS

The artificial somatic-autonomic reflex arc procedure is an effective and safe treatment to restore bladder continence and reverse bladder dysfunction for patients with spina bifida.

Artificial autonomic reflexes: using functional electrical stimulation to mimic bladder reflexes after injury or disease

Autonomic reflexes controlling bladder storage (continence) and emptying (micturition) involve spinal and supraspinal nerve pathways, with complex mechanisms coordinating smooth muscle activity of the lower urinary tract with voluntary muscle activity of the external urethral sphincter (EUS). These reflexes can be severely disrupted by various diseases and by neurotrauma, particularly spinal cord injury (SCI). Functional electrical stimulation (FES) refers to a group of techniques that involve application of low levels of electrical current to artificially induce or modify nerve activation or muscle contraction, in order to restore function, improve health or rectify physiological dysfunction. Various types of FES have been developed specifically for improving bladder function and while successful for many urological patients, still require substantial refinement for use after spinal cord injury. Improved knowledge of the neural circuitry and physiology of human bladder reflexes, and the mechanisms by which various types of FES alter spinal outflow, is urgently required. Following spinal cord injury, physical and chemical changes occur within peripheral, spinal and supraspinal components of bladder reflex circuitry. Better understanding of this plasticity may determine the most suitable methods of FES at particular times after injury, or may lead to new FES approaches that exploit this remodeling or perhaps even influence the plasticity. Advances in studies of the neuroanatomy, neurophysiology and plasticity of lumbosacral nerve circuits will provide many further opportunities to improve FES approaches, and will provide "artificial autonomic reflexes" that much more closely resemble the original, healthy neuronal regulatory mechanisms.

An Artificial Somatic-Central Nervous System-Autonomic Reflex Pathway for Controllable Micturition After Spinal Cord Injury: Preliminary Results in 15 Patients

PURPOSE

Neurogenic bladder dysfunction after spinal cord injury (SCI) is a major medical and social problem for which there is no definitive solution. After the successful establishment in animals of a skin-central nervous system-bladder reflex pathway for micturition we performed this procedure on 15 patients with SCI who had 3 years of followup.

MATERIALS AND METHODS

A total of 15 male volunteers with hyperreflexic neurogenic bladder and detrusor external sphincter dyssynergia (DESD) caused by complete suprasacral SCI underwent limited hemilaminectomy and ventral root (VR) micro anastomosis, usually between the L5 and S2/3 VRs. The L5 dorsal root was left intact as the trigger of micturition after axonal regeneration. Mean followup was 3 years. All patients underwent urodynamic evaluation before surgery and during followup.

RESULTS

Preoperative studies in patients with complete suprasacral SCI revealed hyperreflexic neurogenic bladders and DESD with some differences in storage function during infusion cystometrograms. Of the 15 patients 10 (67%) regained satisfactory bladder control within 12 to 18 months after VR micro anastomosis. Average residual urine decreased from 332 to 31 ml and urinary infection as well as overflow incontinence disappeared. Urodynamic studies revealed a change from detrusor hyperreflexia with DESD and high detrusor pressure to almost normal storage and synergic voiding without DESD. Impaired renal function returned to normal. Two patients (13%) who required a skin stimulator to evoke voiding following the VR anastomosis had partial recovery but more than 100 ml residual urine. One patient was lost to followup and 2 had failure.

CONCLUSIONS

An artificial somatic-central nervous system-autonomic reflex arc can be established surgically to provide a novel method for controlling bladder function in patients with complete suprasacral SCI who have hyperreflexic bladder and DESD. Nerve impulses delivered from the efferent neurons of a somatic reflex arc can be transferred to initiate the response of an autonomic effector.