Flaccid Paralysis

Flaccid paralysis causes muscles to become weak, soft, and difficult or impossible to move after damage to the nerves that normally power them. The Institute for Advanced Reconstruction provides advanced nerve, tendon, and muscle reconstruction for patients with brachial plexus injuries, peripheral nerve injuries, and tendon or muscle loss.

In flaccid paralysis, the problem lies not in the brain’s control centers but in the lower motor neurons—the peripheral nerves and nerve roots that carry signals from the spinal cord to the muscles. These nerves act like the “wiring” that connects the command center to each muscle. When the wiring is cut, stretched, compressed, or otherwise damaged, the muscle stops receiving a meaningful signal to contract.

As a result, the affected muscles become limp, weak, and often completely nonfunctional. The limb may feel heavy or unresponsive, even though the person is trying their hardest to move it. Over time, unused muscles can shrink (atrophy), and joints can become stiff if they aren’t moved regularly. Flaccid paralysis presents a very different picture from spastic paralysis—and requires a different set of treatment strategies focused on restoring or rerouting nerve signals and optimizing the mechanics of movement.

Flaccid paralysis develops when the lower motor neuron pathway is interrupted. This may occur at the level of the spinal cord roots, the brachial plexus or lumbosacral plexus, or along the course of individual peripheral nerves in the arms and legs. Common causes include:

• Brachial plexus injury – Trauma, stretching, or birth-related injury to the network of nerves that control the shoulder, arm, and hand, leading to profound weakness or paralysis.
• Peripheral nerve injury – Nerve cuts, crush injuries, compression, or traction injuries anywhere along the limb that disconnect signals from the spinal cord to specific muscles.
• Tendon or muscle injury – Tendon ruptures, lacerations, or chronic tendon imbalance that prevent otherwise healthy muscles from moving the joints they normally control, sometimes in combination with nerve damage.
• Selected spinal cord or nerve root injuries – Conditions that directly affect the lower motor neurons supplying the limbs.

Because different causes affect different parts of the nerve–muscle pathway, pinpointing the level and severity of injury is crucial for planning reconstruction.

The hallmark of flaccid paralysis is weakness rather than stiffness. Common features include:

• Soft, “floppy” muscles with little or no resistance to movement
• Loss of active movement in part or all of an arm or leg
• Difficulty lifting the shoulder, bending the elbow, extending the wrist, grasping objects, or clearing the foot while walking
• Visible muscle wasting or shrinking over time
• Joint stiffness that develops if the limb is not regularly moved through its full range of motion

If left untreated, prolonged loss of nerve signal can lead to irreversible muscle atrophy, making later reconstruction more challenging. At the same time, joints that are not moved can become stiff, limiting what even successful nerve or tendon surgery can accomplish. This is why early evaluation and therapy are so important in the management of flaccid paralysis.

At The Institute for Advanced Reconstruction, evaluation of flaccid paralysis focuses on understanding exactly where the communication breakdown is occurring and what remains salvageable. A typical evaluation includes:

• Detailed history of the injury or underlying condition
• Physical examination of muscle strength, reflexes, and joint motion
• Identification of which nerves, roots, or plexus segments are likely involved
• Assessment for muscle shortening or joint contracture that may limit reconstruction
• Review of any prior imaging, nerve conduction studies, or surgeries

When appropriate, additional diagnostic studies such as electromyography (EMG), nerve conduction testing, or advanced imaging can help clarify the level of injury and the timeline for nerve recovery. This information is essential for deciding whether to repair nerves, transfer nerves, move tendons or muscles, or focus primarily on bracing and therapy.

Surgical treatment for flaccid paralysis aims either to restore nerve signals to paralyzed muscles or reroute mechanical power from muscles that still work. Options may include:

Nerve Repair and Nerve Transfers

When a nerve has been cut or severely injured, directly repairing it or using a nerve graft can reconnect the pathway from the spinal cord to the muscle. In many cases, surgeons also perform nerve transfers, borrowing a portion of a nearby healthy nerve and connecting it to the nerve of a paralyzed muscle so that new signals can reach it. These procedures are especially common in brachial plexus and peripheral nerve injuries.

Timing is crucial: muscles that have gone too long without nerve input may not fully recover even if the nerve is later repaired. For this reason, early referral to a nerve specialist is strongly encouraged in cases of new flaccid paralysis.

Tendon and Muscle Transfers

When the original muscles are no longer capable of meaningful recovery, tendon transfers or muscle transfers can repurpose functioning muscles to restore key motions. Examples include moving a working tendon to restore wrist extension, finger flexion, or ankle dorsiflexion. In more complex cases, an entire muscle (with its blood supply and nerve) can be relocated to recreate important movements in the arm or leg.

These procedures are carefully planned to preserve overall strength and balance while maximizing practical function, such as the ability to grasp, release, stand, or walk.

Muscle/Tendon Lengthening and Joint Procedures

If flaccid paralysis has been present for a long time, secondary stiffness or joint contractures may need to be addressed. Muscle or tendon lengthening can improve range of motion, while joint release procedures can free a joint that has become structurally stiff. These operations are often combined with nerve or tendon reconstruction to give the limb the best possible alignment and mobility.

Non-surgical care supports muscle and joint health while the team evaluates nerve recovery or prepares for reconstruction. Key elements include:

• Physical and occupational therapy – Guided exercises to maintain joint range of motion, prevent stiffness, and preserve tissue flexibility, along with training in adaptive techniques for daily tasks.
• Splinting and bracing – Custom devices to position the limb for function and safety (for example, wrist-hand splints, elbow supports, or ankle-foot orthoses).
• Rehabilitation medicine and pain management – A physiatrist helps coordinate therapy, manage discomfort, and monitor for complications such as joint stiffness or imbalance.

Even when surgery is planned, keeping the “hinges” (joints) moving well is critical so that any restored power has the best chance to result in meaningful movement.

You may be a candidate for nerve or tendon surgery for flaccid paralysis if:

• You have documented weakness or paralysis from brachial plexus injury, peripheral nerve injury, or tendon/muscle injury.
• There is a clear target for repair, nerve transfer, or tendon transfer based on examination and testing.
• Your joints still have enough motion—or can regain it with therapy—to make reconstruction meaningful.
• You are medically appropriate for surgery and committed to the rehabilitation process that follows.

The team will also consider how long ago the injury occurred, which muscles are still viable, and what your personal goals are, such as returning to work, caring for yourself independently, or resuming specific activities.

The Institute for Advanced Reconstruction is a destination center for complex nerve and paralysis surgery. Working closely with the Center for Hand and Upper Extremity Surgery, our surgeons offer a full spectrum of nerve repair, nerve transfer, tendon transfer, and muscle transfer procedures for patients with flaccid paralysis.

Patients benefit from a cohesive team that includes paralysis surgeons, a dedicated physiatrist, and specialized therapists who understand the unique demands of nerve injury recovery. This comprehensive model ensures that every aspect of care—from diagnosis through surgery and rehabilitation—is aligned around your functional goals and long-term quality of life.

The Institute for Advanced Reconstruction participates in a wide range of insurance plans, including those listed below. However, each physician has their own accepted insurance and hospital affiliations. Before scheduling an appointment, please contact your insurance carrier to confirm that your provider is in-network.

If we are not an in-network provider, our friendly insurance specialists will help you find the most coverage available for your treatment.

• Horizon Blue Cross Blue Shield of New Jersey
• Medicare
• Railroad Medicare
• Aetna
• Cigna
• United Healthcare
• Oxford (Freedom, Liberty)
• MagnaCare

Recovery after surgery for flaccid paralysis is a gradual process. After nerve repair or nerve transfer, it can take months for nerves to regenerate and begin activating their new muscle targets. During this time, therapy focuses on protecting the repair, maintaining joint mobility, and later retraining the brain to use the new nerve pathways.

After tendon or muscle transfer procedures, early recovery centers on protecting the transfer, followed by specific exercises to teach the transferred muscle its new role. With time and consistent therapy, many patients experience meaningful improvements in strength, motion, and independence. Your team will discuss anticipated timelines, potential benefits, and realistic limitations based on the nature and duration of your nerve or tendon injury.