Table 2

Kaplan-Meier estimates of the probabilities of vasectomy success (N = 389). Probabilities of success by follow up week and age (< 35 or ≥ 35 years) for success defined as oligozoospermia and azoospermia.


Probability of success defined as oligozoospermia1 (95% CI)
Probability of success defined as azoospermia2 (95% CI)

Follow-up week
All participants
Age < 35 years
Age ≥ 35 years
All participants
Age < 35 years
Age ≥ 35 years

2
44.9% (39.9, 49.8)
48.7% (40.8, 56.6)
42.3% (36.0,48.7)
25.8% (21.4, 30.1)
22.7% (16.1, 29.3)
27.8% (22.0, 33.5)
5
74.5% (70.1, 78.9)
77.9% (71.4, 84.5)
72.2% (66.5, 78.0)
58.2% (53.3, 63.1)
61.0% (53.3, 68.7)
56.3% (49.9, 62.7)
8
87.7% (84.3, 91.0)
90.0% (85.1, 95.0)
86.1% (81.7, 90.6)
73.6% (69.2, 78.1)
77.6% (70.8, 84.3)
71.0% (65.1, 76.9)
12
94.9% (92.7, 97.1)
97.2% (94.7, 99.6)
93.5% (90.3, 96.7)
85.3% (81.8, 88.9)
91.8% (87.4, 96.3)
81.1% (76.0, 86.2)
16
97.1% (95.3, 98.8)
97.9% (95.5, 100.0)
96.5% (94.2, 98.9)
90.2% (87.2, 93.3)
93.9% (90.0, 97.8)
87.9% (83.6, 96.3)
20
98.4% (97.0, 99.8)
99.3% (97.9, 100.0)
97.8% (95.7, 99.9)
94.0% (91.6, 96.5)
95.9% (92.7, 99.1)
92.8% (89.3, 96.3)
24
98.4% (95.3, 100.0)
99.3% (97.9, 100.0)
97.8% (93.6, 100.0)
98.0% (95.3, 100.0)
98.2% (94.7, 100.0)
98.1% (94.5, 100.0)

1less than 100,000 sperm/mL in two consecutive specimens at least two weeks apart with all subsequent samples showing only rare sperm. 2two consecutive specimens with no sperm at least two weeks apart with all subsequent samples showing only rare sperm

Barone et al. BMC Urology 2004 4:10   doi:10.1186/1471-2490-4-10