Coccygodynia is a painful clinical picture of the sacrococcygeal region.Pain in coccygodynia may be somatic, neuropathic or mixed. There are many studies that emphasize the relationship between vitamin D deficiency and pain.In this study, it is aimed to investigate the severity and type of pain, as well as the effect of vitamin D level on pain in patients with coccygodynia

There are different types of pain in coccygodynia. Patients may suffer from e somatic, neuropathic or mixed pain.Vitamin D plays an important role in the pathophysiology of pain. Vitamin D inhibits NO synthase (iNOS) in microglia and astrocytes. The importance of this is that nitric oxide (NO) is an important molecule in the development of neuropathic pain. NO production contributes to the maintenance of pain hypersensitivity. NO causes central sensitization and mechanical allodynia by increasing spinal cord posterior horn N-methyl-D-aspartate (NMDA) receptors.In the literature, it has been reported that low vitamin D level is associated with the severity of neuropathic pain in postherpetic neuralgia, diabetic neuropathy, rheumatoid arthritis and carpal tunnel syndrome, which cause neuropathic pain development.

Based on the above-mentioned data, in this study, I aimed to investigate the severity and type of pain, as well as the effect of vitamin D level on pain in patients with coccygodynia. Within the scope of the study, 51 patients with a diagnosis of coccygodynia will be recruited. Patients' age, gender, body mass index, duration of symptoms, etiology of coccycodynia, pain severity, pain type and blood vitamin D level will be recorded. Pain assessment (for discrimination between nociceptive, mixed and neuropathic pain) will be done with the painDETECT questionairre. Pain severity will be evaluated with Visual Analog Scale (VAS). Those with vitamin D levels < 20 ng/mL, 20-30 ng/mL, and ˃30 ng/mL will be grouped as deficiency, insufficiency and normal, respectively.The data will be entered into the SPSS (version: 22.0) IBM SPSS statistical package program. Arithmetic mean, standard deviation, min-max, median values will be given in the data obtained by measurement. Percentage and frequency distribution will be given in the data obtained by counting. In statistical evaluations, parametric tests will be used for normally distributed data, and non-parametric tests will be used for data not normally distributed. Relationships will be compared according to the Pearson or Spearman correlation coefficient. Chi-square test will be applied to categorical data. P<0.05 will be considered significant.

Inclusion Criteria:

• Diagnosed with coccygodynia
• 18-70 years old
• Having a vitamin D level determined
• Agreement to take part in the study.

Exclusion Criteria:

• Presence of known polyneuropathy,
• Presence of diabetes mellitus, renal failure, thyroid diseases
• Taking vitamin D replacement therapy,
• Using any of the medications used in the treatment of neuropathic pain such as duloxetine, pregabalin, gabapentin and tramadol, Having undergone an interventional procedure for coccygodynia within 3 months before the evaluation

Patients who applied to Sivas Cumhuriyet University Faculty of Medicine Physical Therapy and Rehabilitation clinic between 01/08/2021 and 28/02/2022 and were diagnosed with coccygodynia and had their vitamin D levels checked will be included in the study.