Validation of the Paris (Functional Coccydynia Effect) Pain Questionnaire for Coccydynia: A Study on Reliability and Validity in the Turkish Population

Coccydynia refers to pain localized in the coccyx and surrounding areas without radiation, significantly affecting quality of life. The condition was first described in 1588, and in 1950, Schapiro referred to it as "television disease." Rectal palpation revealing tenderness in the coccyx strongly supports the diagnosis of coccydynia. Symptoms typically worsen while sitting (especially on hard surfaces), transitioning from sitting to standing, and prolonged standing. Although its etiology remains uncertain, the most common risk factors include internal and external trauma, such as falls and childbirth. While idiopathic cases may also occur, the risk of developing coccydynia is higher in women and individuals with obesity. Coccyx morphology and hypermobility are closely associated with coccydynia, and degenerative changes in the intercoccygeal discs have been implicated as a cause in 41% of idiopathic cases and 44% of traumatic cases. Tumors such as chordoma, osteoid osteoma, and notochordal cell tumors, as well as infections, are other potential causes.

Anteroposterior (AP) and lateral radiographs are the primary imaging modalities used to rule out these conditions and investigate predisposing factors for coccydynia, such as bone spicules, retroverted coccyx, coccygeal subluxation, or scoliosis. Radiographs are also valuable for identifying fractures or dislocations resulting from trauma. Additionally, angular mobility evaluations are performed using dynamic imaging techniques.

Clinical decision-making relies on valid and reliable outcome measures. These measures assess disability levels, functional impairment, treatment effectiveness, and disease progression over time. To be clinically meaningful, an outcome measure must be easy to complete and score, valid, reliable, and responsive to changes. The Oswestry Disability Index (ODI) is a valid, reliable, and responsive assessment tool specifically designed for low back pain. Although it has been widely used in studies assessing disability in coccydynia, it does not include coccydynia-specific functional limitations, such as "pain while transitioning from sitting to standing." Furthermore, ODI includes questions that assess leg pain, which is not relevant to coccydynia.

Similarly, quality of life is commonly assessed using the Short Form-12 (SF-12) in coccydynia research. However, SF-12 is a general health-related quality-of-life measure, rather than a condition-specific tool. Additionally, the Numeric Rating Scale (NRS) has long been used for pain assessment, and despite some criticisms, its use alongside additional questions provides valuable insights.

Assessing coccydynia requires the evaluation of pain and its functional impact, along with condition-specific disability questionnaires. The Paris Pain Questionnaire (Functional Impact of Coccydynia Pain Questionnaire) was developed by Jean-Yves Maigne in 2006 as a condition-specific tool. However, its reliability and validity have not been formally established.[6] While it has not been widely used in subsequent studies, it was reintroduced in 2021 by Jean-Yves Maigne and his team in another study on coccydynia assessment. In this study, a modification was made to the original questionnaire by incorporating pain onset during sitting. Unlike other questionnaires, the Paris Pain Questionnaire assesses aspects of pain that impact daily life, including pain while sitting (beyond intensity alone, as measured by NRS), transitioning from sitting to standing (highly specific to coccydynia with radiological findings), walking, nighttime pain (which is common in severe coccydynia), and pain during travel (a key indicator of coccygeal pain sensitivity). However, a formal validation and reliability study for this questionnaire has not been conducted to date.