Severe nerve pain behind my knee and calf despite pregabalin

Hello everyone, I am a 46-year-old woman, and I am writing because I have been struggling with an extremely painful and unusual condition since 2019. Despite consulting several neurologists, neurosurgeons, and other specialists, and undergoing extensive testing, I still do not have a definitive diagnosis.
I am hoping someone here might recognize my symptoms or have experienced something similar.
My symptoms: My pain started in 2019 in a very small, precise area behind my right knee, approximately 1 cm in size.
The attacks are sudden and excruciating. The best way I can describe the sensation is as if someone were pressing a burning cigarette into my nerve while simultaneously stabbing it with a knife.
Each episode typically lasts between 10 and 30 seconds, occasionally up to 40 seconds.
The pain often builds progressively over several seconds, reaches an unbearable peak, and then disappears abruptly.
During the most severe attacks, I have collapsed to the floor because the pain is so intense.
The strangest aspect is that between attacks, I can be completely pain-free. I do not have constant pain, tingling, or burning sensations.
The attacks can occur while sitting, standing, walking, or lying down. Sometimes they seem to be triggered by twisting my lower back, prolonged sitting, certain movements, stress, or manipulation of the affected area. Other times, they occur without any obvious trigger.
Over the years, I have experienced periods of relative improvement followed by devastating relapses.
Medical investigations: I have undergone extensive investigations in different countries, including the Netherlands and Spain.
Lumbar spine MRIs: Multiple examinations have shown only minor findings, including mild degenerative changes and a small left-sided L5–S1 disc protrusion. These findings do not seem to explain my right-sided symptoms.
Right knee MRIs: No significant abnormalities.
EMG and nerve conduction studies: Repeated several times, most recently in September 2026. All have been normal.
Vascular ultrasound examinations: Normal.
Brain MRI: No relevant abnormalities.
High-resolution and dynamic ultrasound examinations: These included evaluation of the peripheral nerves, particularly the sciatic and peroneal nerves. No definite nerve entrapment was identified.
In September 2026, a specialist performed clinical tests that were positive for piriformis syndrome (deep gluteal syndrome).
In October 2026, an MR neurography examination identified a fibrous band near the sciatic nerve at the greater sciatic notch, deep in the gluteal region. This finding was considered potentially compatible with dynamic sciatic nerve entrapment. However, no specialist has been able to establish whether this fibrous band is actually responsible for my symptoms.

One particularly confusing aspect is that I do not typically experience buttock pain or pain radiating down the entire back of my thigh, which I understand are more common symptoms of deep gluteal syndrome.
Instead, my pain has been extraordinarily localized behind my knee and has now moved farther down into my calf.

Treatment:
In August 2026, after a particularly severe relapse with repeated attacks, I started taking pregabalin (Lyrica). My usual dose has been:
- 150 mg in the morning.
- 150 mg in the evening.
- Total: 300 mg daily.

Initially, pregabalin helped tremendously. For almost two months, the severe attacks became much less frequent, and I finally began to feel that my life was returning to normal. Unfortunately, the medication has also caused significant side effects:
- Memory difficulties.
- Cognitive impairment and brain fog.
- A disturbing sensation of being disconnected from reality.
- Difficulty concentrating.

These effects have been particularly difficult because I work in academia, have substantial professional responsibilities, and have a four-year-old daughter. I desperately want to find a treatment that allows me to function normally without feeling mentally disconnected.
During previous crises, I have also been treated with high-dose corticosteroids and medications for acute pain. I have tried osteopathic treatment and stretching exercises, sometimes with temporary improvement.
My recent relapse: Over the past few days, I have experienced another major relapse, despite continuing to take pregabalin.
During one particularly difficult day, I experienced approximately 11 attacks, some separated by only 10 minutes.
The pain was so intense that I had to interrupt a professional trip to Madrid and return home to Barcelona. My neurosurgeon advised additional pregabalin during the crisis and subsequently prescribed 5 mg of diazepam. What frightens me most is that the attacks have returned despite taking a medication that initially seemed so effective.
I am also increasingly concerned about the fact that the pain has now shifted from behind my knee into my calf. I do not know whether this means the nerve irritation is changing, whether a different nerve is involved, or whether the fibrous band found near my sciatic nerve could somehow explain this progression.
After seven years, I still have no clear explanation for what is happening.
My questions:
Has anyone experienced extremely intense, short-lasting nerve pain attacks (10–30 seconds), with absolutely no pain between episodes?
Has anyone experienced pain that started behind the knee and later moved into the calf?
Has anyone been diagnosed with sciatic nerve entrapment, deep gluteal syndrome, or piriformis syndrome caused by a fibrous band, but without significant buttock or thigh pain?
Can intermittent nerve compression cause such severe attacks even when EMG, nerve conduction studies, and dynamic ultrasound examinations are normal?
Has anyone initially responded very well to pregabalin, only to experience a major relapse despite continuing the medication?
Has anyone found a specialist, diagnostic approach, or treatment that finally helped identify and address the underlying cause?

I understand that nobody here can diagnose me, and I am not asking for medical advice to replace professional care. I am simply hoping to connect with people who might recognize this unusual pattern of symptoms. The pain is so intense that it has profoundly affected my life. What makes it especially difficult is its unpredictability: I can feel completely normal one moment and be overwhelmed by unbearable pain seconds later. I am frightened of the attacks, frustrated by the lack of a diagnosis, and exhausted by the uncertainty.

I would be deeply grateful for any experiences, suggestions, or insights.

Thank you very much for reading my story.