**7. Conclusion**

the first six months of life. There is a significant drop in the incidence of monophasic pattern by the age of four. The complex waveforms prevail in older children and normal adults. There are two components in the dual mode action of such functional sphincter. They are the "myogenic" (primary or immature) component and the "neurogenic" (secondary or ma‐ ture) component. We postulate that the monophasic jet pattern is the result of contraction caused by the myogenic component of the VUJ, while the complex pattern is the result of modulation of the myogenic component of the jet by the neurogenic component in response to the distal intrauretetic pressure (Fig 11). The mode of the functional sphincteric action of the VUJ and the subsequent ureteric jet waveform vary depending upon whether or not the

**Figure 11.** Diagram showing the dual mode of action of the VUJ in the normal population

rently lower velocities and intervening with zero flows.

The presence of the less frequently observed modifications of the ureteric jet pattern is also contributed to the dual mode action of VUJ. The multispike pattern appears to be a prema‐ ture relaxation of the VUJ that precedes the ureteric jet proper. It is related to the relaxation mechanism found in forced diuresis. Forced diuresis is probably caused by permanent re‐ laxation of the VUJ functional sphincter allowing free flow of urine modified by ureteric peristalsis. These modifications are under the control of neural mechanism. The breaks mod‐ ification is found under condition of maximum bladder filling hence increased intravesical pressure. This is probably a result of the pressure wave of the ureteric jet generating appa‐

Whenever the neurogenic component is switched off, only the myogenic component oper‐ ates and thus results in a reversion to the monophasic pattern of the ureteric jet. The above holds true under three physiological conditions. During pregnancy, the hormonal

neurogenic component is active.

126 Recent Advances in the Field of Urinary Tract Infections

The concept of dual mode action (myogenic and neurogenic component) of a functional ac‐ tive sphincter at human VUJ has the following implications:

**1.** Human VUJ function takes time to mature.

**2.** It is important for understanding the physiology of VUJ and the mechanism for predis‐ position to certain pathological conditions, such as VUR and UTI in children

[3] Blok, C., Van Venrooij, G. E. P. M., & Coolsaet, B. L. R. A. (1985). Dynamics of the ureterovesical junction; effectiveness of its ureteral peristalsis in high pressure pig

Functional Anatomy of the Vesicoureteric Junction: Implication on the Management of VUR/ UTI

http://dx.doi.org/10.5772/52168

129

[4] Blok, C., Van Venrooij, G. E. P. M., Mokhless, I., & Coolsaet, B. L. R. A. (1986). Dy‐ namics of the ureterovesical junction:its resistance to upper urinary tract outflow in

[5] Blomley, M. J. K., Ramsey, C. M., Cosgrove, , Patel, N., Lynch, M., Glass, D. M., & Peters, A. M. (1997). The Ureteric Jet Index: a Novel measure of Divided Renal Func‐

[6] Burge, H. J., Middleton, W. D., Mc Clennan, B. L., & Hildebolt, C. F. (1991). Ureteral Jets in Healthy Subjects and in Patients with Unilateral Ureteral Calculi: Comparison

[7] Burke, B. J., & Washowich, T. L. (1998). Ureteral Jets in Normal Second-and Third-

[8] Catalano, O., De Sena, G., & Nunziata, A. (1998). The color Doppler US evaluation of the ureteral jet in patients with urinary colic. Radiol Med (Torino)., 95, 614-7.

[9] Chiu, N. T., Wu, C. C., Yao, W. J., Tu, D. G., Lee, B. F., Tong, Y. C., & Pan, C. C. (1999). Evaluation and Validation of Ureteric Jet Index by Glomerular Filtration Rate.

[10] Cox, I. H., Erickson, S. J., Foley, W. D., & Dewire, D. M. (1992). Ureteric Jets: Evalua‐ tion of Normal Flow Dynamics with Color Doppler Sonography. AJR., 158, 1051-5. [11] Cussen, L. J. (1967). Dimensions of the normal ureter in infancy and childhood. J Ur‐

[12] Diess, J. (1902). Nierenbecken und Harnleiter. In Handbuch der Anatomie des Men‐

[13] Dixon, J. S., Canning, D. A., Gearhart, J. P., & Goslilng, J. A. (1994). An immuno- his‐ tochemical study of the innervation of the ureterovesical junction in infancy and

[14] Dixon, J. S., Goslilng, J. A., Canning, D. A., & Gearhart, J. P. (1992). An immuno- his‐ tochemical study of human postnatal paraganglia associated with the urinary blad‐

[15] Dixon, J. S., Jen, P. Y. P., & Goslilng, J. A. (1998a). Immunohistochemical characteris‐ tics of human paraganglion cells and sensory corpuscles associated with the urinary bladder. A developmental study in the male fetus, neonate and infant. J Anat., 192,

[16] Dixon, J. S., Jen, P. Y. P., Yeung, C. K., Chow, L. T. C., Mathwes, R., Gearhart, J. P., & Goslilng, J. A. (1998b). The structure and autonomic innervation of the vesico-ureter‐

ic junction in cases of primary ureteric reflux. Br J Urol., 81, 146-51.

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As a conclusion, the implication of this chapter is that it will alter the scientific basis in the understanding of VUJ and related pathological conditions.. Doppler ultrasound study of ureteric jet provides a non-invasive, physiological and ethical method to study the physiolo‐ gy and pathophysiology of VUJ. In the future, this is valuable for evaluating the therapeutic approach in different kinds of pathological conditions related to VUJ and bladder detrusor activity.
