Causes

The precise cause and mechanism of Hard Flaccid Syndrome (HFS) remains largely unknown and is a topic of ongoing research and debate. Although the condition’s exact origins are not fully understood at this time, several hypotheses have been put forth to explain how and why it develops.

The Leading Hypothesis#

The leading hypothesis, as proposed by Dr. Irwin Goldstein and colleagues, suggests that HFS is caused by the pathological activation of a pelvic/pudendal-hypogastric reflex. This “pelvic/pudendal-hypogastric reflex” leads to excessive sympathetic activity, causing smooth muscle contraction of the erectile tissue which manifests as the hard, semi-rigid state of the flaccid penis synonymous with and characteristic of the condition.[1]

Goldstein et al. identify multiple anatomical sites where this reflex can be triggered: the penis itself (region 1), pelvis/perineum (region 2), cauda equina (region 3), spinal cord (region 4), and brain (region 5).[1]

Region 1 Pathology#

Region 1 pathology involves issues at the penile level, or the end organ. Traumatic events or injuries to the erect penis are thought to be what causes the excess sympathetic activity for these cases.[1] After describing how he has successfully treated HFS patients who have presented to him with region 3 pathology (cauda equina) in an interview with Dr. Stefan Buntrock, the German urologist known for his “UroChannel” YouTube channel, Dr. Goldstein states that “the usual scenario” for HFS “is injury to the penis,” suggesting that region 1 is the most common pathology for those who have acquired the condition.[2]

Potential triggers include:

• Rough or excessive masturbation
• Rough sex
• Penile enhancement/enlargement techniques such as jelqing or the use of vacuum pumps or traction devices

Region 2 Pathology#

Region 2 pathology pertains to issues occurring in the pelvic/perineal area. In these cases, the likely cause is either neuropathy of the pudendal nerve as a result from traumatic injury, hypertonicity of the pelvic floor, or both.[1]

Potential triggers include:

• Blunt force trauma to the perineum acquired from engaging in activities such as horseback and bicycle riding

Region 3 Pathology#

Region 3 pathology involves dysfunctions in the cauda equina, a bundle of spinal nerves located at the lower end of the spinal cord. This region is critical for transmitting nerve signals between the lower body and the brain. Pathological activation in this area can result from disc protrusions, tarlov cysts or annular tears in the lumbosacral region of the spine, which can compress or irritate the cauda equina nerves and bring about HFS.[1]

Though HFS patients that present with this pathology generally respond poorly to treatment, there have been patients that have significantly improved and even recovered from HFS following spine surgery.[1][2]

Potential triggers include:

• Sacral radiculopathy from annular tears, tarlov cysts, or both

Region 4 Pathology#

For HFS patients with region 4 pathology, the issue originates somewhere further up the spinal cord from the lumbosacral region.[1]

Region 5 Pathology#

For HFS patients with region 5 pathology, the issue originates in the brain.[1]

Recent Developments#

will add the nerve sprouting theory here

Other Causes#

HFS has also been theorized – albeit by anonymous members within the online community – to be caused by the following for some individuals:

**Please note that these "causes" have not been properly researched nor is there any concrete evidence aside from purely anecdotal personal accounts circulated on various internet forums to support any of the following inducing HFS, at least as of right now**

• Posture issues
• Hip issues (impingement or labral tears)
• Prior use of certain drugs, such as SSRIs and Finasteride
• Anxiety or other mental issues
• Chronic stress
• Prostate inflammation
• Deconditioning
• Autoimmune disorders
• Poor diet
• Lack of adequate sleep
• COVID or COVID vaccines
• Pudendal nerve compression
• Venous leak
• Penile fibrosis
• Anal fissure or prolapse
• Hemorrhoids
• Dysautonomia
• Gastrointestinal issues
• Torn suspensory ligament

References#

1. Goldstein, I., Komisaruk, B. R., & Yee, A. (2023, May 4). Hard Flaccid Syndrome Proposed to Be Secondary to Pathological Activation of a Pelvic/Pudendal-Hypogastric Reflex. https://auanews.net/issues/articles/2023/may-2023/hard-flaccid-syndrome-proposed-to-be-secondary-to-pathological-activation-of-a-pelvic/pudendal-hypogastric-reflex

2. “DON’T JELQ before you’ve watched THIS! | UroChannel” YouTube, uploaded by UroChannel, 22 June 2024, https://www.youtube.com/watch?v=psBFjYBKxCk