同济医学院外科医生常士民对肖传国手术的明确质疑


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送交者: coubert 于 2009-08-14, 20:14:26:

baih 于 [教育与学术]

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因为是都是同济的医生,常大夫在严重质疑肖传国吹牛以后,客客气气地加了一句方法还要更多实践验证,其实常大夫根本不信肖的牛皮

RE: AN ARTIFICIAL SOMATIC-CENTRAL NERVOUS SYSTEMAUTONOMIC REFLEX PATHWAY FOR CONTROLLABLE MICTURITION AFTER SPINAL CORD INJURY: PRELIMINARY RESULTS IN 15 PATIENTS
C. G. Xiao, M.-X. Du, C. Dai, B. Li, V. W. Nitti and
W. C. de Groat
J Urol, 170: 1237–1241, 2003
To the Editor. Reconstruction of controlled voiding in spinal cord injury still remains a major challenge in medicine. Xiao et al perxxxxed an interesting investigation first in animals (rat1 and cat2) and then in clinical patients, by establishing the “skin-central nervous system (CNS)-bladder” artificial reflex pathway to trigger bladder contraction. Based on our understanding and clinical experience in bladder treatment of patients with spinal cord injury, we would like to comment on some points regarding the artificial “somatic-CNS-bladder” reflex pathway.

First is the relationship between naturally triggered voiding and artificially triggered voiding. In patients with suprasacral spinal cord injury one or more nature triggering points usually develops to initiate voiding, for example tapping the lower abdomen, pulling the pubis or scratching the skin below the spinal cord injury level. Does the patient who underwent the operation still retain naturally triggered voiding? Furthermore, we do not think the artificial reflex arc can “control” voiding. It may have the same role of trigger point in spastic bladders of spinal cord injury.

In addition, which root should be selected as the recipient? For the donor root in clinic it can be L3, L4, L5 or S1. Considering spine stability, L5 or S1 is preferential. For the recipient root one must consider its normal innervative frequency and efficacy to bladder detrusors. Generally speaking, S2 roots in patients seldom have innervative contribution to bladder detrusor because there is no bladder pressure increase when S2 is stimulated (20 V, 30 Hz). S3 and S4 are the dominant contributors of bladder innervation, with the right side more efficacious.3 Furthermore, the proximal lumbar somatic motor ventral roots innervating the hindlimb muscle are much larger than the distal sacral ventral roots innervating the pelvic organ and floor. Therefore, it is technically possible to anastomose 1 proximal donor root with 2 or 3 distal recipient roots. So in our opinion the recipient root for neurorhaphy should be S3 or S4, bilaterally or unilaterally.

Another point centers on how to promote axonal regeneration to pelvic nerves rather than to pudendual nerves. As we know, the ventral root of L6 in rat, S1 in cat, S2 in dog or S3 in man contains somatic motor fibers as well as parasympathetic preganglionic fibers. The xxxxer xxxxs pudendal nerve to innervate pelvic striated muscles and sphincters, and the latter xxxxs pelvic nerve to pelvic ganglion and then innervate pelvic organs. Theoretically, the proximal somatic motor fibers are more inclined to regenerate into distal somatic nerves because they can release the same neural trophic and growth factors to attract and induce axonal sprouting and regenerating. However, the aim of this operation is to get more reinnervation to bladder and less reinnervation to sphincter. What can we do to inhibit axonal regeneration to distal somatic nerves and enhance to autonomic nerves?

Another question is which is a more efficacious trigger, skin or tendon afferent? Scratching skin induces a superficial spinal reflex, while knocking tendon induces a profundal reflex. The impulse produced by tendon reflex seems more robust than that by skin. However, in animal experiments and clinical sacral anterior root stimulation (Brindley electrode) the intensity of electrical stimulus is hundreds to thousands of times higher than the biological current. Is there any difference between the “skin-CNS-bladder” and “tendon-CNS-bladder” reflex pathway? Which one can give a better result? Another issue regards whether to do deafferentation. It has been proved clinically that sacrificing 4 or even 5 sacral roots has no effect on voluntary voiding or defecation.4 Selective sacral root rhizotomy in patients with supraconal spinal cord injury, whether efferent or afferent, usually gives encouraging initial results but is disappointing in long-term followup.5 Because the plasticity of autonomic nerve and bladder smooth muscle is so strong, only complete denervation could achieve permanent spasm relief.6, 7 In our opinion the “somatic-CNS-bladder” reflex arc only sets up a new somatic trigger point to initiate voiding. It seldom affects bladder compliance and reservoir function. Thus, establishing a “somatic-CNS-bladder” reflex arc without supplementation of appropriate deafferentation will ultimately lead to a hyperreflexic and spastic bladder. What is the role of deafferentation? Does it diminish the efficacy of the somatically triggered voiding?

Finally, establishing an artificial “somatic-CNS-bladder” reflex arc to trigger voiding in patients with spinal cord injury is a new and promising approach. Congratulations to Xiao et al, who present interesting and inxxxxative research work. However, more experimental and clinical studies and long-term followup are needed before a definite conclusion is drawn.

Respectfully,
Shi-Min Chang
Department of Orthopedic Surgery
Tongji Hospital Tongji University
389 Xincun Road
Shanghai 200065
People’s Republic of China
1. Xiao, C. G. and Godec, C. J.: A possible new reflex pathway for micturition after SCI. Paraplegia, 32: 300, 1994
2. Xiao, C.-G., De Groat, W. C., Godec, C. J., Dai, C. and Xiao, Q.: “Skin-CNS-bladder” reflex pathway for micturition after spinal cord injury and its underlying mechanisms. J Urol, 162:936, 1999
3. Chang, S. M. and Hou, C. L.: The frequency and efficacy of differential sacral roots innervation to bladder detrusor in Asian people. Spinal Cord, 38: 773, 2000
4. Anson, K. M., Byrne, P. O., Robertson, I. D., Gullan, R. W. and Montgomery, A. C.: Radical excision of sacrococcygeal tumours. Br J Surg, 81: 460, 1994
5. Torrens, M. and Hald, T.: Bladder denervation procedures. Urol Clin North Am, 6: 283, 1979
6. Brindley, G. S.: The first 500 patients with sacral anterior root stimulator implants: general dexxxxion. Paraplegia, 32: 795, 1994
7. Madersbacher, H.: Denervative techniques. BJU Int, suppl., 85:1, 2000




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