Does inflating an AMS 700 inflatable penile prosthesis compress the dorsal penile nerve, resulting in reduced penile sensation and inability to achieve orgasm?

Dorsal Penile Nerve Compression During AMS 700 Inflation: Addressing Sensation and Orgasm Concerns

The concern that inflating the AMS 700 compresses the dorsal penile nerve causing reduced sensation and inability to orgasm is not supported by objective electrophysiological evidence, though subjective sensory changes are reported by some patients and significantly impact sexual satisfaction when they occur.

Evidence on Penile Sensation After Inflatable Penile Prosthesis

Objective Neurophysiological Data

The most direct evidence comes from electrophysiological testing of penile nerve function. A prospective study using penile electromyography (EMG) in 27 patients (including 3 with AMS 700 CXR devices) found no significant loss of nerve conduction velocity at 3 or 6 months post-implantation 1. Mean nerve conduction values were 29.85 m/s preoperatively, 27.64 m/s at 3 months, and 24.80 m/s at 6 months, with no statistically significant differences (p=0.607 and p=0.276 respectively). This objective data contradicts the hypothesis of mechanical nerve compression from device inflation.

Patient-Reported Sensory Changes

However, subjective sensory perception tells a different story. A 2026 study of 159 IPP patients found that patient-reported penile sensory loss was the single strongest independent predictor of lower sexual satisfaction scores (β = -17.72; P < .001) 2. Importantly, this sensory perception was not associated with surgical approach, device type, complications, or malfunction—suggesting the mechanism is more complex than simple mechanical compression during inflation.

Clinical Implications and Management

Pre-Operative Counseling

The AUA guidelines mandate that patients considering prosthesis implantation be informed of "differences from the normal flaccid and erect penis, including penile shortening" 3. While the guidelines don't specifically mention sensory changes, this should be incorporated into informed consent discussions given the impact on satisfaction.

Common Causes of Dissatisfaction

Historical data on AMS 700 devices identifies the actual drivers of patient dissatisfaction 4:

• Pain (most common complaint)
• Penile appearance concerns
• Need for multiple procedures
• Perceived penile shortening and reduced girth 5

Notably, 83% of patients and 70% of partners reported satisfaction with the AMS 700 in long-term follow-up 4, with more recent data showing median IIEF-5 scores of 21.46 and EDITS scores of 73.11, indicating high satisfaction levels 6.

Addressing Orgasmic Function

Orgasmic dysfunction after IPP is not attributed to nerve compression from inflation. The device provides mechanical rigidity for penetration but does not directly interfere with the neurovascular pathways responsible for orgasm, which involve different anatomical structures than those affected by cylinder inflation. If orgasmic difficulties occur, evaluate:

• Pre-existing orgasmic dysfunction (often present before surgery)
• Psychological adjustment to the prosthesis
• Partner dynamics and expectations
• Concurrent medications affecting sexual function
• Hormonal status (testosterone levels)

Practical Recommendations

If a patient reports reduced sensation or orgasmic difficulty after AMS 700 implantation:

1. Verify proper device function - ensure complete inflation/deflation cycling
2. Assess for surgical complications - infection, erosion, or malposition can cause discomfort that patients may describe as "numbness"
3. Evaluate psychological factors - adjustment to the prosthesis takes time; consider referral for psychosexual counseling 7
4. Check testosterone levels - hypogonadism affects both sensation and orgasmic function
5. Review expectations - the prosthesis provides rigidity, not restoration of natural erectile physiology

Important Caveats

The discrepancy between objective nerve testing (showing no damage) and subjective patient reports (indicating sensory changes) suggests that perceived sensory loss may reflect altered proprioception, psychological adjustment, or changes in penile biomechanics rather than actual nerve compression 2, 1. The inflated cylinders do increase penile girth and alter tissue dynamics, which could change sensory feedback without damaging nerves.

Device inflation does not mechanically compress the dorsal neurovascular bundle in a way that causes permanent nerve damage, as the cylinders are positioned within the corpora cavernosa, not dorsally where the nerves run 8. The dorsal nerves remain superficial to Buck's fascia and are not in the path of cylinder expansion.