Peripheral nerve repair is a procedure that reconstructs an injury that has occurred outside of the sensory nerves that connect the central nervous system, which is the brain, spinal cord down to the limbs. This injury can cause pain, weakness and a paralyzing feeling on the feet and hands. This is also known as peripheral neuropathy

Peripheral nerve injuries have a slow recovery rate as the patient’s ability to heal is weakened by the injured motor and sensory nerves. The neuronal sustentation is supported by hormones’ extracellular matrix that binds and regulates cellular functions, and cytokines that are secreted by some cells. The aim of peripheral nerve repair is to regain the nerve growth factor to be released naturally and recede the occupation of fibroblasts at the injury site.

Symptoms of Peripheral Nerve Injuries

• Acute sensitivity of touch
• Gradual numbness, tingling or prickling sensation in the hands, arms and legs
• Intense or burning pain in the hands and legs

The different types of peripheral injured nerves include:

• Laryngeal nerves which provide sensitivity to the tissues at the vocal cords
• Lingual and inferior alveoli nerves that are a branch of the mandibular nerve
• Iatrogenic spinal sensory nerve that has cervical lymph node as the cause of injury
• Brachial plexus nerve which is located between clavicle and primary rib
• Ulnar nerve injury which is near medial epicondyle of the humerus causing a tingling sensation at the little finger
• Other nerves include radial nerve, Inguinal nerve, phrenic nerve, femoral nerve

Techniques Involved in Peripheral Nerve Repair

The Hollow Tubulization Technique

The hollow tubulization technique, also known as hollow conduits, involves fabrication of hollow cylindrical tubes which are installed using various techniques such as:

• Corneal cross linking: A procedure that uses ultraviolet for preparation of collagen tubes
• Braided peripheral nerve in which different regeneration tubes are braided from poly (glycol ide-co-L-lactide) (PGLA) material which is biodegradable
• Injection molding of low pressure that is thermally induced technique which produce tubes with elongated aligned channels
• Electrospinning, which stimulates active muscles that is given out by an injured nerve as the nerve grows
• Physical film rolling
• Melting extrusion on poly(e-caprolactone) (PLC) which support the attachment and proliferation of neonatal olfactory bulb unsheathing cells (NOBEC)

The goal for hollow tubulization technique is to:

• Segregate the restoration of nerve fiber (axons) from fibrotic tissue
• Continually direct the formation of new tissues
• Protect the revitalization of nerve from the insufficient mechanical forces
• Precipitate the secretion of growth factors that are between the nerve stamps and Schwann cells
• Prevent scar formation and pinched nerve (neuroma)
• Prevent nerve fiber sprouting inefficiently and interference of fibroblast
• Enhance the growth of neurotrophic factors (biomolecules which support survival and growth of neurons)

Hydrogel Fillings for Peripheral Nerve Repair

The hydrogel filling consists of molecules such as polysaccharides, certain proteins, peptides and extracellular matrix (ECM). In hydrogel fillings, hydrogel is injected in the hollow defect of electrospinning of poly-l-lactic acid hollow (electro spun PLLA) where RADA 16-mix hydrogel generates axons and movement of Schwann cells. This recovers the functionality of stance phase of gait (when the foot first touches the ground to when the it leaves the ground). It also enhances the new structure formation of neuromuscular junction.

Intraluminal Fillers for Peripheral Nerve Repair

In this technique, many luminal fillers are used to bridge larger nerve gaps regenerating nerve fiber (axons) through tubulization. The luminal fillers consist of chitosan and collagen which are applied in passage of native nerves of the basal lamina (layer of extracellular matrix produced by epithelial cells).

Freeze-dried Isotropic Cues

Topographic cues enhance the initiation of neurite extension and to gain the isotropic three-dimensional matrix by using a controlled freeze-dried technique done with different polymers. This consist of collagen and chitosan filler which blend to protect growing fiber nerves from being compressed by forces and sufficiently providing spacing for regenerating nerves.

Autologous Nerve Graft

Autologous nerve graft option in nerve repair is used to cover long defects of critical nerve injury. A donor nerve graft is removed from sensory nerves such as medial antebrachial that are expandable, which help in regeneration of Schwann cells, neurotrophic factors, basal lamina and adhesion molecules.

Post-Op Guidelines

When the nerve is healing post the nerve repair procedure, enough rest is recommended to ensure the area has healed, followed with regular checkups at the doctor. When it’s a procedure done to treat a defected nerve, some medications are prescribed to relieve pain, or injections such as corticosteroid maybe administered.

Physiotherapy is also recommended for the essence of restoring function and preventing stiffness occurring at the injured part of the body.

Get in Touch

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