Sperm Quality
Unfortunately, semen quality is also noted to decline after SCI (Deforge et al. 2005). Semen obtained by EEP in the first 2-3 days after injury was scant, but had normal quality by 6-10 days post-injury (Mallidis et al. 1994). After approximately 2 weeks semen quality deteriorates to levels approaching those observed in males with chronic SCI. After 6 months to 1 year, there is no relationship between duration of injury and sperm quality (Sarkarati et al. 1987). Semen quality in men with chronic SCI is reported to have decreased motility and viability, although total numbers of sperm tend to remain high (Brackett et al. 1997b; Ibrahim et al. 2009). Sperm DNA damage, which is another method of assessing semen quality, has also been shown to be higher among men with SCI when compared to able-bodied controls (Brackett et al. 2008). The following studies investigate the effects of various factors on sperm quality, including: repeated ejaculations, different methods of bladder management, antegrade versus retrograde ejaculation, vibratory stimulation versus electroejaculation, surgical extraction, heat and alterations to seminal plasma. In their chapter on fertility after SCI in the book Spinal Cord Injury Rehabilitation, Brackett and Ibrahim (2009) also provide a review of other areas related to sperm quality.
Author Year; Country Score Research Design Total Sample Size |
Methods | Outcome |
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Hamid et al. 2006; UK PEDro=6 RCT Level 1 N=32 |
Population: Men with SCI; Age: mean 40.3-37.1 yrs, range 23-48; Level of injury: above T10; Time since injury: mean 4.8-7.0 yrs, range 0.7-19. Treatment: Weekly penile vibratory ejaculation (PVE) for 3 months vs PVE at baseline and at 3 months. Outcome Measures: Sperm morphology, forward progression, and motility. |
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Brackett et al. 2002; USA PEDro=5 RCT Level 2 N=12 |
Population: Mean age=36.2 yrs, > 2 yrs post-injury, C4-T11. Treatment: Electroejaculation was performed with the Seager Model 14 electroejaculation unit. A total of 99 electroejaculation trials were administered 4-8 weeks apart according to a random schedule. Each trial consisted of continuous or interrupted current delivery. Outcome Measures: Semen quality. |
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Giulini et al. 2004; Italy PEDro=5 RCT Level 2 N=34 |
Population: 34 couples (males with SCI), 21-37 yrs (females), 28-46 yrs (males), paraplegia, tetraplegia, C6-L1. Treatment: The male partner was randomly assigned to single transrectal electroejaculation or multiple (baseline, 1- month, 3- month) transrectal electroejaculation before intracytoplasmic sperm injection (ICSI). Outcome Measures: Sperm concentration, morphology, and motility. |
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Kathiresan et al. 2012; USA Case series Level 4 N SCI=444 N controls=61 |
Population: 444 men with SCI with no known causes of infertility other than SCI; level of injury: 176 cervical, 193 T1-T10, 70 T11-caudal; 115 complete, 126 incomplete. Controls: 61 able-bodied (AB) men, healthy with no history of infertility. Treatment: Retrospective chart review of Male Fertility Research Program participants from 1991 to 2011. Sperm retrieval methods included masturbation, penile vibratory stimulation (PVS), and electroejaculation (EEJ). Outcome measures: sperm retrieval method (masturbation, PVS, EEJ), semen volume, sperm concentration, sperm motility, total sperm count. |
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Qiu et al. 2012; China Pre-post Level 4 N SCI=26 N controls=16 |
Population: 26 infertile men with SCI (primary infertility present in 9), mean(SD) age 33.8(2.9) yrs, mean(SD) DOI 8.6(3.0) yrs (range 1-11 yrs), level of injury: C5-C6 (n=4), T2-T12 (n=22), mean(SD) yrs of infertility 6.8(4.2) yrs; Controls: 16 non-SCI fertile donors (all had previously fathered at least one child), mean(SD) age 32.9(2.1) yrs. Treatment: Collection of semen samples in SCI men using penile vibratory stimulation (PVS) (n=14), percutaneous vasal sperm aspiration (PVSA) (n=12); collection of semen samples in non-SCI donors all by masturbation (n=16). Outcome measures: sperm vitality and DNA integrity, sperm chromosomal aneuploidy. |
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Caremel et al. 2011; Canada Case series Level 4 N=11 |
Population: 11 men with SCI; mean age 29 yrs (range 21-40); 11 complete C5-T6; mean DOI 74 mos, (range 18-163 mos). Treatment: cystoscopic intradetrusor botulinum neurotoxin A injections were performed with 300 units of Botox (n=10) or 1000 units of Dysport (n=3) for overactive bladder. Two patients received two BT injections at 7 months interval using different dosages, were therefore treated as independent tests. Ejaculation tests were done pre- and post-BT injections using penile vibrator stimulation or electroejaculation combined as needed with oral midodrine and/or intracavernous injection or phosphodiesterase inhibitors. Outcome Measures: Ejaculation type and volume, sperm count, mobility, vitality. |
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McGuire et al. 2011; Ireland Case series Level 4 N=31 |
Population: 31 men, 29 with acquired spinal cord injury (complete lesion (n=18), incomplete lesion (n=11). Injury levels: C3-C7; T1-T5; T11-L3), 2 with congenital spinal abnormality. Treatment: Electroejaculatory stimulation (EES) done with Seager model rectal probe; n= 27 (87%) underwent EES once, n=4 (13%) underwent EES several times. Outcome measures: The Mann-Whitney U test, semen analysis (volume, density, motility, normal morphology and live sperm); pregnancy rate. |
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Ibrahim et al. 2009; USA Prospective controlled trial Level 2 N=24 |
Population: 12 men with traumatic SCI and 12 able-bodied men as controls. Treatment: Sperm sample from each subject was divided into 4 groups: Group 1: no treatment; Group 2: added phosphate buffered saline (PBS); Group 3: monoclonal antibodies (MAB) against target cytokines IL6, IL-1β, and TNF-α; Group 4: receptor interference agents (RI) against the same cytokines. Outcome Measures: Sperm concentration; sperm motility; sperm viability; Sperm DNA damage (DFI). |
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Hibi et al. 2008; Japan Post-test Level 4 N=8 |
Population: 8 participants with cervical SCI and neurogenic anejaculation (age 26 – 46, mean 35.6). Treatment: Retrograde vasal sperm aspiration (ReVSA). Outcome Measures: Presence of motile sperm. |
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Kanto et al. 2008; Japan Case control Level 3 N=56 |
Population: 22 men with SCI (age 21-41); data on 34 men with obstructive azoospermia was obtained retrospectively for control. Treatment: Testicular sperm extraction (TESE); if unsuccessful, microdissection TESE was performed, followed by intracytoplasmic injection (ICSI) Outcome Measures: Fertilization; pregnancy. |
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Brackett et al. 2007; USA Pre-post Level 4 N SCI=11 N controls=5 |
Population: 11 men with SCI and 5 ablebodied men; Age: mean(SD) range 31.9(2.3)-30.7(3.6) yrs; Level of injury: C4 to T11; mean(SD) time since injury 9(2.0) yrs. Treatment: Agents added to sperm to neutralize cytokines (IL-1beta, IL-6, and TNF-alpha) at the receptor level. Outcome Measures: Percentage sperm motility. |
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Das et al. 2006; UK Case series Level 4 N=16 |
Population: 16 men with SCI; Age: median 37 yrs, range 24-46; Level of injury: C4-L1; Impairment: complete (n=9), incomplete (n=7); Time since injury: median 12.5 yrs, range 5-43. Treatment: Repeated electro-ejaculation (3 successive EE at 2-4 week intervals). Outcome measures: Semen volume, sperm concentration, sperm motility, sperm variability, and total motile sperm concentration. |
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Salsabili et al. 2006; Iran Case series Level 4 N SCI=89 N controls=49 |
Population: 89 men with SCI and 49 ablebodied men; mean(SD) age: (SCI) 34(3.7) yrs, (AB controls) 36(4.76) yrs; Injury levels C4-L2, all complete; Time since injury range 11-18 yrs. Treatment: 1) Semen collection by electroejaculation (EE), masturbation penile vibratory stimulation (PVS) or percutaneous epididymal sperm aspiration (PESA); 2) Intracytoplasmic sperm injection (ICSI). Outcome measures: Quality and quantity of sperm, including sperm count, volume, PH, density, motility, viscosity, and white blood cells. |
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Cohen et al. 2004; USA Pre-Post Level 4 N = 17 |
Population: 17 men with SCI, mean age 35.2 yrs. Treatment: Antegrade semen specimens from all participants split into 8 groups. Group 1: no treatment. Group 2 to 8: semen treated with different combinations of monoclonal antibodies to IL1-β, IL6, and TNF-α. Outcome Measures: mean sperm motility. |
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Monga et al. 2001; USA Prospective controlled trial Level 2 N=12 |
Population: 7 participants with SCI, 5 fertile age matched donors, age range=27-54 yrs, 5 to 31 yrs post-injury, C4-C7, 5 incomplete, 2 complete. Treatment: Electrovibratory stimulation. Outcome Measures: semen quality. |
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Brackett et al. 2000; USA Prospective controlled trial Level 2 N=26 |
Population: 12 men with SCI, 14 ablebodied controls; Age (men with SCI): range 29-40 yrs; Injury level: C4-L1; Mean time since injury: 14.6 yrs; Able-bodied controls all had vasectomy and biological children. Treatment: 1) sperm retrieved by electrical stimulator or vibratory stimulation for participants with SCI, 2) sperm retrieval before exposure to the seminal and prostatic fluids during vasectomy surgery in controls and vas aspiration surgery in participants with SCI. Outcome Measures: Sperm quality. |
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Mallidis et al. 2000; Australia Post-test Level 4 N=9 |
Population: 9 men; Age: mean 28 yrs, range 22-36 yrs. Treatment: Electroejaculation using CGS Electroejaculator with progressively increasing sine wave current at 20 Hz over 4 consecutive days. Outcome Measures: Semen quality. |
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Chen et al. 1999; USA Post-test Level 4 N=14 |
Population: 14 men; Age: range 25-41 yrs, Injury level: 8 cervical, 6 thoracic; Impairment grade: Frankel A (n=8), B (n=4), and C (n=2); Hip flexion reflex in 13 (93%) and spasticity in 12 (86%). Treatment: Antegrade sample obtained using Ling vibrator. Bladder catheterized for collection of any retrograde ejaculate. Vibratory stimulation at clinic every 2-4 wks. Outcome Measures: Sperm quality. |
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Brackett et al. 1997a; USA Prospective controlled trial Level 2 N=77 |
Population: 77 males, 45% cervical, 51% thoracic, 4% lumbar. Treatment: 1) vibration (n=23), 2) electroejaculation (n=44) or 3) underwent both procedures (n=10). Outcome Measures: Sperm quality. |
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Brackett et al. 1997b; USA Prospective controlled trial Level 2 N=19 |
Population: 10 men with SCI, 9 agematched men without SCI; Age: mean 33.1 yrs; Injury level: C4-C5 (n=5), T5-T6 (n=4), T12 (n=1); Time since injury 11.4 yrs. Treatment: Electroejaculator (Seager model 14, 1-10 Volts) or laboratory stimulation. Specimens stored at room temperature (23°C) or body temperature (37°C). Outcome Measures: Semen quality, fertility rates. |
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Ohl et al. 1997; USA Prospective controlled trial Level 2 N=11 |
Population: All males. Treatment: n=5 FertiCare Clinic Vibrator (2.5 mm, 100Hz, for 3 min) or electroejaculation (Seager model 11). Outcome Measures: Sperm quality. |
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Brackett et al. 1996; USA Prospective controlled trial Level 2 N=26 |
Population: 12 men with SCI; Age: range 18-42 yrs; Injury level: thoracic; Time since injury: range 3-28 yrs; Age matched controls (n=14). Treatment: Vibratory stimulation (SCI) or masturbation (controls). Effect of SCI seminal plasma was tested on control sperm and vice versa. Outcomes Measures: Seminal parameters. |
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Matthews et al. 1996; USA Case-control Level 3 N=40 |
Population: 18 men with SCI and 22 men without SCI; Injury level: 2 cervical, 15 thoracic, 1 lumbar, 33 of 40 men were in a relationship with a female. Treatment: Retrospective review of electrical stimulator with rectal stimulation followed by intrauterine insemination (126 cycles in n=33) or in vitro fertilization (n=7 total 14 cycles). Outcome Measures: Fertility rates, seminal parameters, ejaculatory rates, cycle function, pregnancy rates. |
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Rutkowski et al. 1995; Australia Case series Level 4 N=70 |
Population: 70 men with SCI, Age: mean 30 yrs, range 19-59 yrs; Injury level: C1-C8 (n=36), T1-T9 (n=19), T1-T9 (n=15), T10-L2 (n=15); Mean time since injury: 6 yrs. Treatment: Vibroejaculation at 10-50Hz, 3 cycles for 45seconds (n=36) or electroejaculation (n=34). Outcome Measures: Seminal parameters, type of catheterization, method of ejaculation. |
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Padron et al. 1994; USA Pre-post Level 4 N SCI=9 N controls=10 |
Population: 9 men with SCI and 10 ablebodied men; Age: (SCI) mean 30.2 yrs, SEM=1.2, (controls) mean 24.3 yrs, SEM=3.6; Injury level: cervical 33%, thoracic 55%, lumbar 11%; Time since injury >1yr. Treatment: Cryopreservation of sperm by liquid nitrogen vapor only (V) vs vapor for 12 minutes followed by submersion into liquid nitrogen (V+N2) vs direct submersion into liquid nitrogen (N2). Outcome measures: Mean percent motility in fresh sperm samples, post-thaw percent and grade of motility. |
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Wang et al. 1992; Taiwan Post-test Level 4 N=25 |
Population: 32 men; Age: range 18-40 yrs; Injury level: C4-L1, 23 tetraplegia, 9 paraplegia, 5 incomplete, 27 complete Treatment: Vibrator stimulation (29/32 participants with hip flexion reflex) or electrostimulation (3 participants), 4-6 months of ‘at-home’ treatment, 1x/week stimulation. Outcome Measures: Semen quality. |
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Chapelle et al. 1988; France Prospective controlled trial Level 2 N=148 |
Population: 135 men with SCI and 13 age matched controls; Age (men with SCI): range 18-47 yrs; Impairment grade: complete. Treatment: 0.2mg physostigmine. Outcome Measures: Ejaculation rates and procreation, level of injured metamers, testicular volume. |
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Halstead et al. 1987; USA Post-test Level 4 N=12 |
Population: 12 men with SCI; Age: range 23-38 yrs; Injury level: C5-C6 (n=4), T3-T12 (n=7), L1 (n=1), paraplegia (n=8), tetraplegia (n=4); Impairment grade: AIS A (n=7), B (n=1), C (n=3), D (n=1); Time since injury: range 0.5-18 yrs. Treatment: Rectal probe electroejaculation on 38 occasions. Outcome Measures: Ejaculation response and sperm quality. |
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Sarkarati et al. 1987; USA Post-test Level 4 N=34 |
Population: 34 men with SCI; Age: range 16-36 yrs; Injury level: 14 cervical (3 complete, 11 incomplete), 13 thoracic T1-T9 (all complete), 7 T10-L3 (3 complete, 4 incomplete). Treatment: Vibratory stimulation and/or electrostimulation. Outcome Measures: Ejaculation response, semen quality. |
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da Silva et al. 2016; Brazil Case Control Level 3 N=23 |
Population: 23 individuals; 12 SCI patients (mean age=38±10 years) and 11 controls; level of injury ranged from C4 –T6. Treatment: Antegrade semen specimens were collected using penile vibratory stimulation (PVS). Controls collected semen by masturbation in specific sterile containers after at least 3 days, but not longer than 7 days, of ejaculatory abstinence. Outcome Measures: Sperm concentration (millions of sperm/ml ejaculate), total sperm count, sperm motility (% with forward progression), seminal white blood cell (WBC) concentration (millions of WBC/ml ejaculate). |
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Krebs et al. 2015; Switzerland Cross-Sectional Level 5 N=16 |
Population: 16 men with SCI and suffering from anejaculation. 28 semen samples underwent long term cryopreservation of more than 3 years and total sperm motility of >5% or viability of >10%. Treatment: None. Semen quality analysis both prior to and after a median of 11 years of cryopreservation. Outcome Measures: Semen quality, motility, and viability. |
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Ibrahim et al. 2014; USA Prospective Controlled Trial Level 2 N=32 |
Population: Semen samples from 32 men with SCI (mean age=38 years; level of injury C3 to L1; mean time post-injury=14 years) were collected. All participants were past the period of spinal shock (≥ 12 months) and were in general good health with no active urinary tract infections. Treatment: Semen was obtained using the standard methods of penile vibratory stimulation (PVS) or electroejaculation (EEJ), where each subject served as their own control. Each sample was divided and treated with a vehicle control, normal goat IgG-control, or with a polyclonal antibody against ASC. Outcome Measures: Sperm concentration, total motile sperm count (TMSC), and four grades of sperm motility using the World Health Organization (WHO) method. |
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Ibrahim et al. 2015; USA Prospective Controlled Trial Level 2 N=45 |
Population: 30 men with spinal cord injury and 15 age-matched control participants. Treatment: None. Outcome Measures: the present study measured serum concentrations of inhibin B and anti-Mullerian hormone (AMH). |
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Ibrahim et al. 2015; USA Pre-Post Level 4 N=18 |
Population: 18 men with SCI who ejaculated regularly by penile vibratory stimulation (PVS) or ejaculation. Treatment: Probenecid was administered in phases. Phase 1 had participants receive 250 mg orally twice a day for 1 week. Phase 2 had participants who completed phase 1 with no complications were given 500 mg orally twice a day for 3 weeks. Semen was analyzed at three time points: Pre-treatment (Pre-Rx), 1-2 days before Phase 1; Posttreatment (Post-Rx), 1-2 days after completion of Phase 2; Follow-up (F/U), 4 weeks after completion of Phase 2. Outcome Measures: sperm motility |
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Ibrahim et al. 2017; USA Pre-post Level 4 N=20 |
Population: 20 men with SCI who ejaculated regularly by penile vibratory stimulation (PVS) or ejaculation. Treatment: Probenecid was administered for 4 weeks (250 mg twice a day for 1 week, followed by 500 mg twice a day for 3 weeks). Semen quality was assessed at three time points: pre-treatment, post-treatment (immediately after the 4-week treatment), and follow-up (4 weeks after the last pill was ingested). Outcome Measures: Sperm motility |
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Discussion
Results from studies vary, however, in general they show similar reductions in sperm parameters in antegrade and retrograde samples, except for decreased motility in non-alkalinized retrograde samples and one study which showed antegrade samples were better in motility and viability than retrograde samples (Ohl et al. 1997). There is also some evidence to suggest that vibratory stimulus seems to produce more viable samples than electroejaculation in terms of motility (Ohl et al. 1997; Le Chapelain et al. 1998). Semen quality appeared to improve with repeated ejaculations in some series (Matthews et al. 1996; Giulini et al. 2004; Hamid et al. 2006), and not in others (Sarkarati et al. 1987; Das et al. 2006). It has been suggested that parameters improve with consecutive days of electroejaculation (Mallidis et al. 2000). Once-weekly vibrator stimulation resulted in an increase of semen volume and of fructose and acid phosphatase levels in the seminal plasma (suggesting improved function of the seminal vesicles and prostate) (Siösteen et al. 1990), whereas other investigators reported that too frequent ejaculation caused semen quality to deteriorate (Wang et al. 1992). The possibility of improvement in semen parameters appears to be related to consistency of ejaculations over a regulated time period. One study found improved sperm motility after 3 months of weekly PVS performed by patients at home (Beretta et al. 1989). The majority of studies, however, found no statistically significant improvement in sperm motility after regular ejaculation by PVS or EEJ (Siosteen et al. 1990; Sonksen et al. 1999; Das et al. 2006; Hamid et al. 2006).
Poor sperm motility may be due in part to the seminal plasma secondary to disturbed nervous systems and anejaculation (Brackett et al. 2000, 2007a), and there may also be alterations in testicular function or morphological anomalies in the sperm (Chapelle et al. 1988; Elliott et al. 2000; Monga et al. 2001). Sperm aspirated from the vas prior to exposure to seminal fluid in men with SCI had significantly better motility (54% vs 14%) and greater viability (74% vs 26%) in comparison to sperm retrieved from same group by VS or EE (Brackett et al. 2000). These researchers had previously demonstrated an inhibitory effect of SCI seminal plasma on normal sperm motility, as well as improvement of SCI sperm motility when prepared with normal seminal plasma (Brackett et al. 1996). In addition, the same group (Brackett et al. 2007a; Cohen et al. 2004) have recently shown that cytokines in the semen of men with SCI may play a key role in inhibiting sperm motility, with inactivation of the relevant receptors leading to improved sperm motility. Both studies (Cohen et al. 2004; Brackett et al. 2007a) examined the effect of treating semen with different combinations of antibodies on motility and both found that sperm motility significantly increased with the combination of antibodies that acted against all 3 relevant cytokines. In a prospective controlled trial, Ibrahim et al. (2008) found no damage to sperm treated with cytokine inhibitors and suggested that further studies investigating cytokine inhibitors as a therapy for low sperm mobility are warranted. Probenecid has shown promising results to improve sperm motility (Ibrahim et al. 2017).
Once ejaculated, sperm motility in men with SCI declines rapidly, and storing at body temperature (in a 37°C incubator) may exacerbate this (Brackett et al. 1997b). Bladder management also seems to affect sperm quality, with low pressure emptying by clean intermittent catheterization improving semen quality over indwelling catheterization, reflex voiding or straining (Ohl et al. 1989; Rutkowski et al. 1995). Ibrahim et al. (2014, 2015) found that slight improvement in sperm motility were achieved after treatment with anti-ASC polyclonal antibody (mean sperm motility increased from 11.5% to 18.3%) and after probenecid treatment (sperm motility increased from 18% to 25%).
Padron et al. (1994) showed a similar reduction in sperm motility (65%) in men with SCI to normal with thawing after cryopreservation, preferring the vapor only method. Krebs et al. (2015) found that complete tetraplegia has a negative effect on pre-cryopreservation sperm viability and post-cryopreservation motility, and that there were no differences between the semen parameters of samples collected early (up to 3 weeks) after SCI, those collected later, or those collected using assisted ejaculation techniques. Given this and reported reliability of retrieval methods, there seems no point in cryopreserving semen for later insemination unless collected acutely within the first 1-2 week window while sperm quality is still normal (Mallidis et al. 1994).
Botox treatment for detreusor dyssynergia has beneficial and detrimental effects on ejaculation function (Caremel et al. 2011). The detrimental effects involve retrograde ejaculation and reduced semen volume, which result from reduce contraction of the smooth muscle sexual accessory due to the toxin. A beneficial effect is improved semen quality due to the reduced contamination of the semen by urinary infection.
Conclusion
There is level 2 evidence (Brackett et al. 1997a; Ohl et al. 1997) that using a penile vibratory stimulus produces samples with better sperm motility than from electrostimulation.
There is level 2 evidence (from 1 weak RCT: Brackett et al. 2002) that sperm obtained by antegrade samples has better motility than retrograde samples and that interrupted current produces higher sperm motility than continuous current.
There is level 4 evidence (Rutkowski et al. 1995) that bladder management by clean intermittent catheterization (with low pressure filling and emptying) may improve semen quality over indwelling catheterization, reflex voiding or straining.
There is level 4 evidence (Caremel et al. 2011) that botox injections to the overactive bladder may reduce semen volume, but increase semen quality.
There is level 4 evidence (Hibi et al. 2008) that retrograde vasal sperm aspiration can retrieve sperm of sufficient motility to afford pregnancy.
There is level 2 evidence that SCI sperm quality can be improved by placing sperm from SCI in able-bodied seminal plasma (Brackett et al. 1996), and that aspirated sperm from the vas deferens has better motility than that ejaculated (Brackett et al. 2000), demonstrating the etiology of poor semen quality may lie within the seminal plasma in men with SCI. These techniques have not been studied clinically with respect to pregnancy rates.
There is level 4 evidence (Cohen et al. 2004; Brackett et al. 2007a) that interference with receptors to all 3 cytokines in semen can improve sperm motility.
There is level 2 evidence (Ibrahim et al. 2009) that monoclonal antibodies and receptor interference agents do not change the degree of DNA fragmentation in sperm from subjects with SCI.
There is level 3 evidence (Kanto et al. 2008) that testicular sperm extraction followed by intracytoplasmic injection is an effective way to induce pregnancy, with fresh sperm giving better results than frozen-thawed sperm.
There is Level 2 evidence (Ibrahim et al. 2014, 2015) that found slight improvements in sperm motility were achieved after treatment with anti-ASC polyclonal antibody (mean sperm motility increased from 11.5% to 18.3%) and after Probenecid treatment (sperm motility increased from 18% to 25%).
There is Level 5 evidence (Krebs et al. 2015) that found complete tetraplegia has a negative effect on pre-cryopreservation sperm viability and post-cryopreservation motility, and that there were no differences between the semen parameters of samples collected early (up to 3 weeks) after SCI, those collected later, or those collected using assisted ejaculation techniques.