Intrathecal Baclofen Pump and Sacral Root Stimulation
An intrathecal baclofen pump is a device for treatment of severe spasticity. This medical device is placed under the skin during a surgery (generally under abdominal skin) and is used to deliver baclofen directly into the intrathecal space surrounding the spinal cord. Baclofen stimulates GABA-B receptros and acts as a skeletal muscle relaxant.
For sacral anterior root stimulation (SARS) implantation, a laminectomy is performed between S2-L4 to expose the sacral nerve roots of S2-S4 and possibly S5 (Worsoe et al. 2013). Anterior and posterior nerve roots are distinguished using intraoperative stimulation (Worsoe et al. 2013; Creasey et al. 2001). Then the sleeved electrodes are placed bilaterally along the S2-4 anterior roots and sutured onto the target nerves (Creasey et al. 2001). Meanwhile, the S2-5 posterior root nerves are sacrificed through a bilateral rhizotomy. This procedure enables urinary continence during stimulation, maintenance of bladder capacity, and reduces the risk of AD by abolishing the reflex arcs mediated by these nerves (Valles et al. 2009; Creasey et al. 2000). The electrode cables are then subcutaneously tunneled between the costal margin and iliac crest and connected to a subcutaneous transmitter box in the anterior abdominal wall (Creasey et al. 2001). The transmitter box and subsequently the stimulation can be activated by the patient using a wireless receiver block.
| Author Year; Country Score Research Design Total Sample Size |
Methods | Outcome |
|---|---|---|
| Lombardi et al. 2008 (males) Italy Prospective Comparison trial Level 2 N=54 |
Population: 54 males with SCI (mean age 42.8) suffering from Lower Urinary Tract Symptoms (LUTS) and concomitant erectile impairment. Group A – 30 neurogenic patients, (mean age 41.3; range 27–69), all showing at least partial peripheral or central preservation of the upper motor neuron. 6 had incomplete SCI, 3 had myelitis, 1 had MS, 2 had disk herniation, and 2 had peripheral polyneuropathy. Group B consisted of 24 idiopathic patients (mean age 44.6; range 27–62). Treatment: To evaluate if sacral neuromodulation (SNM) using the InterStim system improves erectile function. Stimulation consisted of continuous pulses with a frequency of 20 Hz. Outcome Measures: the five-item version of the International Index of Erectile Function (IIEF-5) A score of IIEF-5 equal to or higher than 25% compared to baseline indicated remarkable clinical enhancement. Three months after permanent implantation, the IIEF-5 was completed again. Those who benefited significantly in erectile function completed the IIEF-5 semiannually. A final checkup was performed in July 2007. |
1. In the first post-SNM visit, there was a significant improvement in the median IIEF-5 score of group A (Neurogenics) (from 14.6 (range 11–18) to 18 (range 12–23) using the Wilcoxon test (P<0.02). 2. The patients’ history revealed that erectile impairment was concomitant to LUTS (Fisher test P=0.008) in 12 neurogenic subjects compared to two idiopathic subjects. 3. Overall, 22 out of 52 males (42.3%) showed erectile impairment according to the IIEF-5. More precisely, 14 out of the 29 neurogenic patients (48.2%) and 8 out of the 23 idiophatic patients (34.7%) showed erectile impairment. |
| Lombardi et al. 2008 (females) Italy Prospective Comparison trial Level 2 N=31 |
Population: 31 women, 17 of whom had neurogenic bladder dysfunction with permanent SNM implanted. Group A comprised 18 neurogenic individuals, with mean age of 37.4 years (range 23–48). All of them showed at least partial peripheral or central preservation of the upper motoneuron confirmed with appropriate neurophysiologic investigations. Group B comprised 15 idiopathic females, with mean age of 37.4 years (range 25–46). All neurological diseases were excluded in these subjects using appropriate neurophysiologic tests such as anal sphincter electromyography. Treatment: To evaluate if SNM improves sexual function in females treated with SNM for lower urinary tract dysfunction. Outcome Measures: Improvement in blood sexual function as measured by the Female Sexual Function Index (FSFI) and the Female Sexual Distress Score (FSDS). |
1. Four out of 11 participants showed clinically significant improvement in sexual health (an increase of 60% of the total score or of one FSFI domain, or 50% improvement on the FSDS). 2. Mean duration of sexual improvement was 23 months. 3. The positive effects regarding sexuality may be due either to enhancement of LUTS or to the direct stimulation of the sacral roots (S3). |
| Sievert et al. 2010 Germany Case control Level 3 N=16 |
Population: N: 16 Level: all thoracic; all complete; all AIS Score A Etiology: traumatic Experimental Group N: 10 Age: Mean 30.5 years, Range 19-38 years Control Group – N: 6 Age: Mean 36.5 years, Range 27-47 years Treatment: Sacroneuromodulation Stimulation (SNS) (Interstim- I & II) bilaterally implanted at the third sacral foramen. Control group was people with SCI given an antimuscarinic medication prescription with no stimulation. Follow-up schedule: 3 and 6 months, then every 6 months thereafter. Outcome Measures: bowel movement details (participant diaries), laxative use, and QOL questionnaire |
1. The group with Sacral Neuromodulators (experimental group) reported sufficient colon movement without oral laxatives 2. People in the Stimulation group reported higher QoL than the controls: more independent and “normal social participation”. 3. With additional Interstim- II programming, two patients experienced improved erectile function that permitted satisfying sexual intercourse. |
| Calabrò et al. 2014 Italy Pre-post Level 4 N=20 |
Population: 20 men (mean age 34.85±10.27 years) affected by severe spasticity due to SCI (10), vascular (3), degenerative (6) and congenital (1)d origins; level of lesion C4 – T10 with a mean disease duration of 6.1±4.45 years Treatment: Implantation of a Synchromed pump with port and a drug administration device (DAD) with a 20mL reservoir. Intrathecal baclofen was administered through the pump and port system (mean dose of 75±25 mg/day). Outcome Measures: All patients underwent neurological and sexological tests using the International Index of Erectile Function (IIEF) and the Diagnostic Impotence Questionnaire (DIQ) before pump implantation and approximately 2 months after implantation. All participants underwent specific clinical scales to evaluate force, muscle tone, cognition and mood, and specific sexual questionnaires, including a semi-structured interview. |
1. Decrease in the IIEF median scores before and after implantation. 2. Spasticity, spasms, and patient’s perception of their own quality of life (QoL) improved after ITB administration but with a worsening of sexual functions. 3. Found a correlation between ITB dosage and IIEF scores (ρ=-0.60; P < 0.05). 4. Before implantation, 55% of participants declared difficulties to achieve or maintain an erection, whereas after the pump implant 80% of the sample suffered from erectile dysfunction. |
| Lombardi et al. 2011 Italy Pre-post Level 4 N=75 |
Population: N: 75 men (8 completed NBS outcomes) Level: incomplete Duration: > 6 months Treatment: using sacral neuromodulation (SNM) implanted at third sacral foramen. and comparing: before (14 day baseline) vs. after implantation . Follow-ups after: 1, 3, and 6 months then every 6 months after that. Outcomes: SF-36 QoL questionnaire, frequency of incontinence, frequency of evacuations, duration of evacuations, Wexner fecal incontinence and constipation questionnaires, pad usage, anorectal manometry and International Index of Erectile Function (IIEFS; male sexual function questionnaire). |
1. Individuals (6) with neurogenic erectile dysfunction had a 37.4% improvement in IIEFS score and engaged in sexual intercourse without needing oral phosphodiesterase 5 inhibitor. |
| Jones et al. 2008; USA Pre-post Level 4 N=7 |
Population: 7 men with SCI (mean age 36.7 yrs) with positive bulbocavernous reflex and reported history of sexual activity since injury. Treatment: Implantation of intrathecal baclofen pump. Outcome Measures: Brief Sexual Function Inventory (BFSI) questionnaire; perception of spasticity questionnaire, developed by Schwartz et al.; SF-36 Health Survey. |
1. Generally unchanged rating of perceived sexual functioning, sexual relationships, and ejaculation postimplant. 2. Modest to drastic improvements in the participants’ perception of problems with sexual functioning. 3. In 3 participants, there was a relationship between baclofen dosage and perceived sexual function; as baclofen dosage increased, BFSI scores related to erections deteriorated. 4. Significant improvement in the spasticity scores from pre- to postimplant. 5. Improved health status score in all but 1 subject. |
| Denys et al. 1998 France Pre-Post Level 4 N=5 |
Population: 3 female and 14 male participants. Time between injury and operation ranged from 1 to 15 years. All had a complete lesion of the spinal cord: in 16 cases situated between T1 and T10; in one patient at C5. Treatment: Implantation of intrathecal baclofen pump (average dose of 290(68.3) μg/day). Outcome Measures: yes or no questions (ability to sustain reflexive & psychogenic erections, obtain ejaculation without electrical, vibratory, pharmacologic stimulation); visual analog scale for penile rigidity; recall of maximal duration of stable erection (minutes); modification of libido. |
1. Ability to sustain erections was not affected by treatment. 2. 3/5 participants reported decreased rigidity after treatment. 3. 4/5 participants reported decreased erection duration after treatment while 1 subject reported increased duration after treatment. 4. One subject who had the ability to obtain ejaculation without electrical, vibratory or pharmological stim before treatment was no longer able after treatment. This ability returned after baclofen withdrawal. |
| Van der Aa et al. 1995 Netherlands Post-test Level 4 N=17 |
Population: 5 men with SCI (mean age 35.8 yrs); all participants with sacral reflexes and reflexive bladder. Treatment: Implantation of the Finetech-Brindley bladder controller (Sacral anterior neuromodulator). Outcome Measures: Four days after surgery, bladder capacity, continence, and sexual function were measured. |
1. A sustained full erection can be achieved in all our male patients using continuous stimulation; in 12 patients by stimulation of the $2 anterior roots; in 2 patients by stimulating the $3 anterior roots. There is no interference with bladder emptying. |
Discussion
Implantation of a Sacral Anterior Root Stimulator (Brindley et al. 1982) for bladder control usually entails rhizotomy of posterior sacral roots to improve bladder capacity and compliance and reduce reflex incontinence and possibly sphincter spasticity, but in so doing has the disadvantage in men with SCI of abolishing reflex erection, and ejaculation when present. While not the primary indication for implantation, continuous stimulation of S2 or S3 anterior roots has been shown to achieve a sustained and full erection in all of a series of 14 men with complete SCI lesions between C5 –T10 level (van der Aa et al. 1995). Vignes et al. (2001) reported that 60 percent of men with complete SCI were able to achieve an erection by continuous stimulation of S2 roots.
We found 3 studies (Lombardi et al. 2008; Lombardi et al. 2011; Sievert et al. 2010) that used Sacroneuromodulation Stimulation (SNS) in an effort to correct lower urinary tract dysfunction and that also measured sexual function. Proportions of participants in each study recovered erectile function and/or genital arousal; though more research with larger sample sizes are needed.
Concerns have been raised about the impact of intrathecal baclofen (a drug to control spasticity) on sexual function among men with SCI. Baclofen may have an effect on sexual function presumably secondary to the inhibition of visceral afferent input to the lumbosacral spinal cord (Steers et al. 1992). Jones et al. (2008) reported that although there was minimal impact on sexual function after baclofen pump implantation, there was a possible dose response between baclofen and sexual function (i.e. higher the dose to control spasticity, poorer the erection function). Four out of seven subjects noted a decrease in perceived sexual function following an increase in baclofen dosages, although some were utilizing PDE5i as well, and one subject reported a dramatic improvement in rating of sexual function with increase and later tapering in baclofen dose. Denys et al. (1998) reported similar inconsistent findings leading the authors to conclude that the effects of baclofen on sexual function seem to be transitory and reversible with withdrawal or reduction in dose. More recently, Calabro et al. (2014) found that before implantation, 55% of participants declared difficulties to achieve or maintain an erection, whereas after the pump implant 80% of the sample suffered from erectile dysfunction.
Conclusion
There is level 2 evidence (Lombardi et al. 2008) that Sacral neuromodulator stimulation can improve erectile function while simultaneously improving lower urinary tract dysfunction.
There is level 4 evidence (Denys et al. 1998; Jones et al. 2008; Calabro et al. 2014) that implantation of intrathecal baclofen pump, while effective in managing spasticity, may cause difficulties with erection and sexual function.
There is level 4 evidence (Lombardi et al. 2008) that implanting a sacral neuromodulator can improve sexual health and ability to achieve and maintain erection in men with SCI.
