"Effect of Low Level Laser Therapy on Neuropathic Pain After Neck Dissection Surgery''

Patients diagnosed with head and neck cancer are treated with surgery, radiation therapy and/or chemotherapy, with the aim of maximizing survival whilst preserving physical form and function .The surgical dissection of the neck is a typical technique for the management of head and neck malignant growths from the squamous cell carcinoma .

Neck dissection (ND) is performed for known metastatic neck disease, prophylactically in cases where there is increased risk for occult metastatic disease or as a staging procedure. Neck dissection (ND) is used to treat known metastatic neck disease, as a preventative measure against occult metastatic disease. A common surgery for treating malignant growths of the head and neck caused by SCC is surgical ND.

There are various approaches to performing the neck dissection surgery. One of these approaches is the radical neck dissection that involves the total excision of lymph nodes from one side of the neck, the muscle that helps turn the head (sternocleidomastoid muscle), a significant vein (internal jugular vein), and a nerve that is essential in the full-range of movement of the arm and shoulder (spinal accessory nerve).In contrast, the modified radical neck dissection preserves one or more of the aforementioned important structures .

Neck morbidity was common and apparent after cancer treatment; this includes limited ROM, impairment of sensations, and neck pain . In an investigation of 25 patients with permanent neck pain following neck dissection, two types of neck pain were described;neuropathic and myofascial pains.

Furthermore, shoulder and neck symptoms were reported in 37% and 33% of 220 participants who had neck dissection surgery , respectively, while myofascial and neuropathic pains were reported in 46% and 32% of the patients, respectively .

A new definition of pain has been formalized and adopted by International Association for the Study of Pain in January 2020, which states that pain is "An unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage".

Surgical resection of a tumor is associated with intractable pain of the shoulder, neck, and craniofacial areas. Correct identification of structures such as the cervical plexus and the spinal accessory nerve reduces the manifestation of chronic pain states . Parwis Agha-Mir-Salim et al. showed the essential role played by the cervical plexus in the development of chronic pain with neuropathic characteristics after several types of radical neck dissections. The cervical plexus is essential for sensory innervation of the cervical region and the skin of the shoulder. It is formed by the anterior division of the first four cervical nerves and it is a sensory anatomical substrate for this region .

Damage of the cervical rootlets during neck dissection may lead to neck sensory abnormality (anesthesia, numbness, and/or neuropathic pain), edema and limitation of neck/shoulder movement, decline in speech and eating abilities.

Neuropathic pain is usually managed with a variety of pharmacological and non-pharmacological therapies Among nonpharmacological treatments Transcranial Electrical Stimulation , acupuncture, massage therapy and Transcutaneous .Recent studies have reported the use of laser therapy in patients with peripheral somatosensory neuropathy and neuropathic pain .Specifically, clinical studies on the effects of laser therapy on injured nerve reported an increase in nerve function .