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CHAPTER 26
(Fig. 169), but may also develop as a result of a stone lodged in the urethra (Fig. 169).
Diverticula can be easily demonstrated by urethrography. The incidence of this com
plication varies with different authors. Comarr & Bors (1951) reported 61 (50 per cent)
diverticula amongst 122 patients. Bunts (1958) found 4-6 per cent in 1,000 patients and
Griffiths & Walsh (1961) found 19 (9-5 per cent) diverticula in routine urethrograms on
200 patients.
Treatment
With regard to treatment of urethral diverticula it was always our practice to leave
a small diverticulum untreated unless it increases in size, accumulating infected urine
and debris and thus becoming a permanent source of maintaining infection. Griffiths &
Walsh considered the inversion or invagination of the sac into the urethra, as recom
mended in the American literature, as undesirable, as this procedure results in urethral
obstruction with all its complications. Before contemplating excision of a diverticulum
of larger size the patient is instructed how to evacuate the sac by digital compression
after micturition, to prevent stagnation of urine, and this can be associated with urethral
washouts. Large, especially multiloculated urethral diverticula and those resulting in a
fistula, naturally need surgical treatment.
Bors & Comarr (1955-58) reported perineal urethral diverticula as a result of complete
ischiectomies including the pubic ramus and damage to the urogenital ramus, an operation
carried out for repair of pressure sores. We have not seen that serious complication in our
material, as we consider such radical procedure unnecessary.
(4) Stone-formation
There are two main factors causing formation and growth of stones in the upper urinary
tract following spinal cord injuries:
a Infection, especially with urea splitting organisms producing alkaline urine, which
favours precipitation of calcium phosphate, ammonium magnesium phosphate and
calcium carbonate, and
b Hypercalciuria resulting from decalcification of bones, caused by enforced bedrest
and recumbency leading to stagnation of the urine flow. The nucleus of a stone may be
formed primarily within the renal tissue or the so-called RandalPs plaque (Randall,
1937), in the basement membrane of a tubule or beneath the epithelium of the renal
papilla, and from there it finds its way into a renal calyx. On the other hand, a stone may
develop in the urinary passages as a result of precipitation of salts or as a result of infection
resulting in tiny semi-solid lumps of coagulated fluid or dead epithelium. Nordin
et al.
(1967) distinguish between two main types of renal stones according to whether, (i) in
addition to calcium phosphate, they contain either calcium oxalate, associated with
increased excretion of calcium or oxalate or both, and (2) magnesium ammonium
phosphate (MAP) which is associated with chronic infection of the urinary tract. There
is no doubt that in our material stones removed from paraplegics are of MAP type.
In the development of bladder stones, foreign bodies, in particular fragments of the
