Quadruple hourglass-like constrictions of the radial nerve in neuralgic amyotrophy treated by focal resection and in-situ autograft reconstruction: a case report

The human nervous system is a vast network of cables that carry electrical signals from the brain to the muscles, telling them when to move. Sometimes, these cables can become damaged or blocked, leading to paralysis or weakness. One specific condition, known as neuralgic amyotrophy, often begins with sudden, severe pain in the shoulder or arm, followed by the muscles losing their ability to work. For decades, doctors believed that when this condition caused a nerve to look twisted or pinched in multiple places along its length, the entire section of the nerve between those pinches was dead and useless. The standard thinking was that if a nerve looked this damaged, the only solution was to cut out the whole sick section and replace it with a healthy piece of nerve taken from another part of the body.

However, a new case report challenges this long-held assumption. It tells the story of a woman whose arm was paralyzed by four distinct pinches in her main arm nerve. Instead of removing the entire damaged section, surgeons decided to cut out only the worst pinches and leave the nerve tissue in between. The result was a substantial recovery of movement, suggesting that even when a nerve looks severely injured, the internal structure that guides new growth might still be intact and waiting to be used.

The patient was a thirty-six-year-old woman who had been healthy until she woke up with a sudden, sharp pain on the outside of her left upper arm. The pain was so intense it woke her from sleep, and it was accompanied by a numb feeling in the area of the thumb and index finger. Within a week, her wrist and fingers stopped working entirely, leaving her unable to lift her hand or straighten her fingers. This rapid progression from pain to total paralysis is a classic sign of the condition known as neuralgic amyotrophy. While she had recently recovered from a flu-like illness, doctors could not say for certain if the virus caused the nerve problem. After a month of waiting and taking medication that did not help, she was referred to a specialist team at Huashan Hospital in Shanghai.

Before any surgery, the medical team used high-resolution ultrasound, a type of imaging that can see inside the nerve, to map the damage. They found something unusual: four distinct, hourglass-shaped pinches along the main radial nerve, which runs down the arm. These pinches were spaced out over a nine-centimeter stretch, with the nerve narrowing severely at four specific points. The nerve looked twisted and crushed at these spots, but the tissue connecting them appeared continuous. Electromyography, a test that measures electrical activity in muscles, confirmed that the nerve signals were completely blocked below the shoulder, and the muscles were showing signs of dying off because they were not receiving messages.

The surgical team faced a difficult choice. The traditional approach would have been to cut out the entire nine-centimeter section of the nerve containing all four pinches and replace it with a long graft from another nerve. However, the surgeons noticed that while the pinched spots were crushed, the nerve segments in between, though diseased, still held their shape and were not broken. They decided to try a different strategy. They carefully removed only the three most severe pinches near the top of the arm. Instead of discarding the nerve tissue between these cuts, they kept it. They treated these middle sections as natural bridges, sewing the healthy ends of the nerve to the preserved middle sections, and then sewing those to the next healthy section. They left the fourth, mildest pinch at the bottom of the arm alone, simply loosening the tight outer covering to relieve pressure. No nerve was taken from elsewhere in her body.

The recovery process was slow but steady. Three months after the operation, new electrical signals began to appear in the muscles closest to the shoulder, showing that the nerve fibers were starting to grow again. By eight months, these signals had traveled further down the arm, reaching the muscles that control the fingers. At fourteen months, the woman had regained near-normal use of her wrist and fingers, with active thumb extension exceeding forty-five degrees. The ultrasound scans confirmed that the nerve remained a continuous tube across the three places where it had been sewn together, and the electrical tests showed that the signals were successfully passing through the repaired sections.

This case suggests that the severe paralysis seen in this condition is often caused by the specific pinched points acting as physical barriers that stop signals from passing, rather than the entire length of the nerve being destroyed. Even though the nerve between the pinches had lost its ability to send signals, the internal scaffolding that guides new nerve growth remained intact. Once the physical blockages were removed, the nerve fibers were able to use these preserved pathways to grow back to the muscles. The fact that the woman recovered so well without needing a nerve graft from another part of her body indicates that surgeons might be able to save more of a patient's own nerve tissue in similar cases, provided they can identify which parts are truly blocked and which parts are still usable.

The success of this operation also highlights the importance of looking closely at the specific structure of a damaged nerve. In the past, a nerve that looked this damaged on a scan might have been assumed to be beyond repair without a full replacement. This report shows that a detailed look at the nerve can reveal that some parts are still viable. While the patient's sensory feeling in the skin of the thumb and index finger did not fully return, the return of muscle movement demonstrates that the motor pathways were successfully reconnected. The findings suggest that for patients with multiple pinches in a single nerve, the goal of surgery should be to remove the specific blockages while preserving the connecting tissue, rather than assuming the whole section is lost. This approach could lead to better outcomes and less invasive procedures for people suffering from this painful and debilitating condition.