Table 7. Characteristics of studies of vas ligation using metal clips

Authors and Year of Publication / Type of Study / Subject’s Eligibility Criteria / Sample Size* / Setting / Study Period / Interventions / Type and Number of Surgeons
Isolation Method / Occlusion
Method

Metal clips (C) compared with suture material (S)

Leader et al.
1974 [44] / Case series with historical and concurrent controls / Adequate follow-up among 3,015 vasectomies performed between 1970 and 1974 / C: 484
S: 2227 / Office,
USA / C: April 1972 to December 1972
S: June 1970 to June 1972 / Two lateral openings / C: Hemoclip (n=?) + Excision (10-20 mm)
S: Cotton + Excision (10-20 mm) / Urology 2nd year residents
Gupta et al.
1977 [30] / Randomized clinical trial / Men requesting sterilization (35 to 50 years old)
Exclusion unspecified / C: 50
S: 50 / Unspecified,
India / Unspecified / One midline opening / C: 2 tantalum Hemoclips at 5mm distance (some may had only one clip) + vas uncut
S: Silk + Excision (10 mm) + FB (distal end) / Unspecified
Bangstrup and Pederson
1977 [35] / Before-and-after prospective trial / All patients operated in two hospital departments
Exclusion unspecified / C: 200 / 229
S: 124 / 169 / Community hospital,
Denmark / C: December 1974 to March 1976
S: March 1973 to October 1975 / Unspecified / C: Hemoclips (n=4?) + Excision (10-20 mm)
S: Catgut + Excision (10-20 mm) / General surgeons
Same unspecified number per technique
Clausen et al.
1983 [31] / Quasi-randomized clinical trial / 81 consecutive males requesting bilateral vasectomy / C: 39
S: 40
2 patients excluded after assignment / Unspecified,
Denmark / Unspecified / One midline opening / C: 2 tantalum clips at 10 mm distance + vas uncut
S: Silk + FB (distal end) / 2 providers for both groups
Two clips (2C) compared with four clips (4C) per vas
Moss
1972 [27] / Case series with historical controls / Consecutive bilateral vasectomy / 2C: 169
4C: 400 / Unspecified / Before 1972 / One midline opening / 2C: 1 tantalum Hemoclip per vas segment (2 clips per vas) + vas cut (excision ?)
4C: 2 tantalum Hemoclips per vas segment (4 clips per vas) + vas cut (excision?) / One gynaecologist

* Number of subjects analysed/total number of subjects enrolled in the study

C: clip, 2C: 2 clips, 4C: 4 clips, S: suture, RCT: Randomized clinical trial, QRCT: Quasi-randomized clinical trial, FB: folding back.

Table 8. Outcome measures of studies of vas ligation using metal clips

Authors and Year of Publication / Effectiveness / Complications
Data Collection / Length of Follow-up / Post-vasectomy Semen Analysis (SA) / Data Collection / Length of Follow-up / Method of Follow-up / Main Outcome Measures
Timing of SA / Definition of Failure

Metal clips (C) compared with suture material (S)

Leader et al.
1974 [44] / Retrospective / Unspecified but variable / 6 weeks to 3 months until one azoospermic result / No number, motility, nor time specified / Retrospective / Unspecified but variable / Spontaneous medical consultations / Major: Hematoma, granuloma (tender mass occurring more than 21 days), epididymitis, orchitis, fistula, ligature abscess, hydrocele. Minor: cellulitis, vasitis, cutaneous abscess
Gupta et al.
1977 [30] / Prospective / 12 months / 1, 2, and 3 months / Presence of sperm. No number, motility, nor time specified / Prospective / 12 months / Exam day 3 and 7. Exam and questionnaire at 6 and 12 months / Pain, infection, vasitis/epididymo-orchitis, hematoma, hydrocele, granuloma (palpable nodule), dissatisfaction with the operation
Bangstrup and Pedersen
1977 [35] / Prospective / Unspecified but variable / At least 3 months / Presence of motile or non motile sperm. No number nor time specified / N/A / N/A / N/A / N/A
Clausen et al.
1983 [31] / Prospective / 6 months / Each month until 2 azoospermic results + all subjects at 6 months / No number, motility, nor time specified / Prospective / 6 months / Blinded clinical assessments else unspecified / Consumption of analgesics, wound infection, hematoma, epididymitis
Two clips (2C) compared with four clips (4C) per vas
Moss
1972 [27] / Retrospective / Unspecified but variable / 8 weeks, 4 months and 1 year / No number, motility, nor time specified / N/A / N/A / N/A / Complications available only for one group (4C): Infection, hemorrage, spermatic granulomas, pain, pain medication, time to return to work

C: clip, 2C: 2 clips, 4C: 4 clips, S: suture , SA: seman analysis, N/A: not applicable.

Table 9. Quality assessment of studies of vas ligation using metal clips

Authors and Year of Publication / Study Design* / Sample Size /

Comparability

/

Effectiveness Assessment

/

Complication Assessment

/ Global Assessment
Total / Power* / Participants / Study Period / Setting / Provider / Follow-up / Sample Size / Compliance/ Follow-up rate / Adequate Comparability* / Explicit Criteria / Blinded / Systematically Performed in All Men / At the Same Time / Adequate Assessment* / Follow-up Rate* / Explicit Criteria / Blinded / Systematically Performed in All Men / At the Same Time / Adequate Assessment* / Follow-up Rate*
C vs S / Leader et al. 1974 [44] / 3 / 2711 / 0.94 / ? / No / Yes / No / ± / No / ? / No / No / ? / Yes / No / No / ? / Yes / No / No / No / No / ? / Low
Gupta et al. 1977 [30] / 1 / 100 / 0.14 / ? / Yes / ? / ? / Yes / Yes / Yes / Yes / No / ? / Yes / Yes / No / S: 100%
C: 100% / No / No / Yes / Yes / No / S: 100%
C: 100% / Moderate
Bangstrup and Pederson 1977 [35] / 2 / 324 / 0.34 / Yes / No / Yes / Yes / ± / ± / ± / Yes / No / ? / Yes / No / No / 84% / N/A / N/A / Low
Clausen et al. 1983
[31] / 1 / 79 / 0.12 / ± / ? / ? / ? / Yes / Yes / Yes / No / No / Yes / Yes / Yes / Yes / 98% / No / Yes / Yes / ? / No / 98% / Moderate
2C vs 4C / Moss
1972 [27] / 3 / 569 / 0.48 / ? / No / ? / Yes / No / ± / ? / No / No / ? / Yes / Yes / No / ? / No / No / ? / No / No / ? / Very Low

*Criterion used for global assessment (see Table 2, Additional file 1)

C: clip, S: suture, N/A: not applicable.

Table 10. Results of studies of vas ligation using metal clips

Authors and Year of publication / Effectiveness (Failure) / Complications
Based on SA / Based on Pregnancy / Comments / Hematoma /

Infections

/ Pain / Granuloma / Epididymitis / Others / Total / Comments

Metal clips (C) compared with suture material (S)

Leader et al.
1974 [44] / C: 0 to 2 ( 0 to 0.4%)
S: 6 to 9 (0.3 to 0.4%) / N/A / Description of failure unclear. Higher or similar failure risk with sutures than with clips / C: 6 (1.2%)
S: 9 (0.4%) / C: 2 (0.4%)
S: 50 (2.2%) / C: 0%
S: 1 (0.04%) / C: 6 (1.2%)
S: 44 (2.0%) / C:
Major 2.7%;
Minor 0.6%
S:
Major 4.4%; Minor 1.9% / Overall higher risk of complications with suture. Similar risk when analyses restricted to concurrent periods: C: Major 2.7%; Minor 0.6%; S: Major 3.3%; Minor 1.0%
Gupta et al.
1977 [30] / C: 0
S: 0 / C: 0
S: 0 / Similar failure risk but very small sample size / C: 0%
S: 2% / C: 0%
S: 8% / C: 4%
S: 10% / C: 2%
S: 8% / C: 2%
S: 4% / Dissatisfac-tion
C: 2%
S: 10% / Higher risk of complications with sutures than with clips. Very small sample size
Bangstrup and Pedersen
1977 [35] / C: 1 (0.5%)
S: 8 (6.5%)
P < 0.01 / 1 pregnancy, included in SA results / Significantly higher failure risk with suture material than with clips / Complications unspecified
Clausen et al.
1983 [31] / C: 1 (2.6%)
S: 1 (2.5%) / N/A / Similar failure risk but very small sample size / C: 0%
S: 0% / C: 1 (2.6%)
S: 0% / C: 0%
S: 0% / Similar analgesics consumption / Similar risk of complications. Very small sample size
Two clips (2C) compared with four clips (4C) per vas
Moss 1972 [27] / 2C: 2 (1.2%)
4C: 0 / 2C: Unspecified
4C: 0 pregnancy / Lower failure risk with 4 clips than with 2 clips One failure in the 4C group (1-2 motile sperm per high power field after 1 year) in a patient with 2 clips per vas and vas uncut / 4C: 0% / 4C: 0% / 4C: 0% / Complications not available for 2C group

SA: Semen analysis; C: clip, 2C: 2 clips, 4C: 4 clips, S: suture, N/A: not applicable.