Chronic Postsurgical Pain

Change in Brief Pain Inventory (BPI) score from 1 week preoperative to 1, 3, 6, and 12 months postoperative

The BPI assesses pain location, pain intensity at worst, least, average, and right now as well as the degree to which pain interferes with activities of daily living (e.g., sleep, relationships, and mobility). Items are scored on an 11-point scale (0 = does not interfere, 10 = completely interferes) creating a total interference score ranging from 0-120 (higher scores mean more pain interference). The BPI has been adapted for and tested with individuals with severe CP, resulting in excellent internal consistency (Cronbach's alpha = 0.89) and validity evidence \[1, 29, 30\]. The BPI will take parents/children 1-2 minutes to complete.

Dalhousie Pain Interview (DPI)

The DPI uses a 10-item survey to quantify pain intensity (Primary outcome variable; scored 0-10 with higher scores indicating more pain), duration (minutes/seconds in pain), and pain frequency (number of pain episodes) for each type of pain reported in the last week. The type and dose of pain-related medications is also collected. The DPI was developed to assess acute and chronic pain in children with developmental disabilities. The investigative team has considerable experience with the DPI and pain parameters have shown sensitivity to change after treatment \[30, 31\]. The DPI will take parents/children 5-15 minutes to complete.

Numeric Rating Scale (NRS)

The NRS of pain is considered the 'gold standard' and has been widely used to quantify pain intensity (0-10 scale; 0=no pain, 10=worst possible pain). We will use the NRS specific to head, shoulders, upper arm, elbow, forearm, wrist/hand, back, hip, upper leg, knee, lower leg, ankle, and foot pain. The NRS will complement the DPI since it is joint-specific, which is a critical element to capture when assessing orthopedic outcomes. The NRS will take parents/children 3 minutes to complete.

SNAKE (Schlaffragebogen für Kinder mit Neurologischen und Anderen Komplexen Erkrankungen)Sleep Questionnaire

We will also collect the SNAKE Sleep Questionnaire via parent-report, a 43-item tool that measures the sleep environment, sleep patterns, and sleep behaviors (scores ranging from 23-92 with higher scores indicating more sleep difficulties). This tool was designed specifically for individuals with severe disabilities, and individuals with CP were included in the validation sample. The SNAKE will take parents 2-5 minutes to complete.

Gait Outcomes Assessment List (GOAL)

The GOAL had initial data published on it in 2011 \[33\]. It was developed for individuals with ambulatory CP and their parents as a comprehensive assessment of gait-related function. It is an outcome tool that incorporates all domains of the International Classification of Functioning, Disability and Health, including the influence of environment and personal factors \[34\].It contains 7 different domains and scores for each domain and for the total survey are standardized and range from 0 (worst) to 100 (best). A novel component of the GOAL is that it also incorporates the family's priorities for treatment.