Protein intake in spinal fusion surgery can prevent paraspinal muscle atrophy by maintaining muscle mass, regeneration, and growth. Also, by reducing the amount of pseudarthrosis, pain and disability can have a positive effect on recovery.

The high prevalence of this type of surgery, the instability and degeneration of adjacent surfaces of fused sections, lumbar muscle atrophy, increased muscle tissue fat, and negative impact on patient recovery, also with regard to the fact that research has so far aimed to determine The effect of protein supplementation on para-spinal muscles has not been studied in patients undergoing posterior lumbar spine fusion surgery, therefore clinical trials are necessary. In this trial patients undergoing elective posterior spine fusion surgery are divided into two groups of intervention or control.

A randomized, double blind, controlled trial will be conducted in patients undergoing elective posterior spine fusion surgery in Tehran, Iran. After a full review of the inclusion and exclusion criteria and explanation of the risks and benefits of the study, written consent form will be completed. The participants are 80 eligible posterior spine fusion surgery patients, aged ≥ 18 years. Intervention patients will be received 36 grams of protein supplement along with diet containing 1.2 g/kg/day of protein for 30 days after surgery and control patients will be received maltodextrin along with diet containing 1.2 g/kg/day of protein 30 days after surgery. Patients will be evaluated for occurrence of paraspinal muscles after 3 months surgery

Inclusion Criteria:

• Adult patients 18-65 years
• Body mass index 18.5-30
• Candidate for the elective posterior spine fusion
• Without history of severe liver disorder
• Without history of Kidney disorder
• Without history of diabetes
• Without history of trauma and fracture of the vertebral
• Without history of osteoporosis
• Without history of Gastrointestinal malabsorption
• Without history of Parathyroid gland disorders
• Without taking medications that affect the metabolism of bone, such as calcitonin, bisphosphonate, corticosteroid
• No smoking
• Without history of neuromuscular diseases such as dystrophies and neurological disorders

Exclusion Criteria:

• Allergy or intolerance to protein or maltodextrine supplement
• Unwillingness to continue cooperation