Implanted electronic devices, such as pacemakers and defibrillators, are subject to rare mechanical complications. Twiddler’s Syndrome, first described in 1968, involves the physical manipulation of the device after implantation. The condition is named after the patient’s repeated, often subconscious, act of “twiddling” or rotating the device within its surgical pocket.
Defining Twiddler’s Syndrome and Its Mechanism
Twiddler’s Syndrome results from the patient intentionally or unintentionally manipulating the implanted pulse generator. The generator houses the battery and electronic circuitry. Repetitive rotation of the generator inside its subcutaneous pocket causes the attached wire leads to twist and coil around the device itself.
This coiling action shortens the functional length of the leads, causing them to retract or migrate from their intended position. For a cardiac pacemaker, the lead tip is pulled away from the inner wall of the heart chamber where it was secured. The extent of migration varies, sometimes leading to complete dislodgement from the heart. The amount of space in the surgical pocket, or pocket size, plays a significant role; a larger pocket provides more room for the generator to rotate. This process compromises the electrical connection needed for the device to pace or sense heart activity effectively.
Affected Medical Devices and Patient Risk Factors
While Twiddler’s Syndrome was originally documented in patients with cardiac pacemakers, other implanted electronic devices are also vulnerable. Devices like implantable cardioverter-defibrillators (ICDs) and neurostimulators, such as spinal cord stimulators, can be affected. Any device with a generator and a lead system placed beneath the skin surface is potentially susceptible to mechanical manipulation.
Several patient-related and technical factors increase the probability of Twiddler’s Syndrome developing. Patients with psychological conditions, such as cognitive impairment or compulsive disorders, are at greater risk due to a higher likelihood of manipulation. Advanced age is also a factor, as the subcutaneous tissues in older patients may have increased laxity, allowing the device to rotate more easily. A primary technical risk factor is the size of the implantation pocket relative to the device. Factors like obesity or significant weight loss after implantation can also contribute to a looser pocket environment.
Recognizing the Clinical Signs of Device Malfunction
The physical consequence of lead displacement is the loss of the device’s ability to perform its function. For patients with cardiac devices, the primary issue is the loss of pacing or sensing function. This can manifest as symptoms related to a slow heart rate (bradycardia), such as dizziness, lightheadedness, or fainting (syncope).
The displaced lead can also inadvertently stimulate nearby nerves, creating unusual, rhythmic symptoms. If the lead stimulates the phrenic nerve, for example, the patient may experience hiccups or abdominal muscle twitching. Stimulation of the brachial plexus, a network of nerves in the shoulder, can cause rhythmic arm twitching. The patient may also notice visible signs, such as the pulse generator appearing rotated or upside down beneath the skin.
A diagnostic X-ray often reveals the characteristic “Twiddler’s sign,” showing the leads tightly coiled around the generator, confirming the diagnosis. For implantable cardioverter-defibrillators, lead malfunction can lead to inappropriate or painful shocks, or the inability to deliver a shock when needed.
Prevention and Corrective Strategies
Preventing Twiddler’s Syndrome begins with surgical technique during the initial implantation procedure. The surgeon must aim to create a snug, appropriately sized pocket to minimize the space available for the generator to move. A crucial preventive step is firmly securing the pulse generator to the underlying fascia or muscle using specialized non-absorbable sutures. This anchoring technique physically restricts the movement of the device, making it harder for the patient to rotate it.
Patient education is also a foundational part of prevention, particularly for high-risk individuals. Patients and their caregivers must be counselled on the importance of avoiding manipulation and recognizing early signs of malfunction. Once Twiddler’s Syndrome is diagnosed, surgical revision is the standard corrective strategy. This procedure involves reopening the surgical pocket, uncoiling the leads, and repositioning them back to their correct anatomical location. If the leads have been damaged by the twisting, they may need to be replaced entirely. After repositioning, the generator is secured with sutures to the underlying tissue to prevent recurrence.