The IMPACT Study: Personalized Physical Therapy for Better Recovery and a Stronger Core After Hernia Surgery

BACKGROUND AND RATIONALE

Ventral hernia repair (VHR) is among the most common general surgery procedures in the United States, with more than 600,000 repairs performed annually. Standard post-operative care, consisting of activity restriction and an abdominal binder, addresses tissue healing but not the neuromuscular, biomechanical, or psychosocial dimensions of abdominal core health (ACH). Persistent ACH deficits contribute to chronic pain, functional limitation, impaired quality of life, and hernia recurrence. In a national population-based cohort of 587,384 patients with ventral hernia, elective repair was associated with a reduced hazard of bowel obstruction but not with fewer functional ACH diagnoses, and only 16.3% of repaired patients received any physical therapy (PT).

Genuine clinical equipoise exists regarding structured PT after VHR. Plausible mechanisms and observational signals suggest benefit, but no randomized trial has reported results, surgeons commonly counsel activity restriction out of concern that early loading could compromise repair integrity, and structured PT imposes cost and burden during recovery. A definitive trial is warranted, but it cannot be designed responsibly until five operational uncertainties are resolved: whether post-VHR patients enrolled in an observational cohort will accept randomization; whether clinicians other than the developer can deliver an adaptive protocol with fidelity; whether participants will adhere to six in-person sessions and be retained through a blinded 12-week assessment; whether randomized enrollment can achieve parity with a substantially minoritized and publicly insured surgical population; and whether the assessment battery and passive electronic health record (EHR) follow-up are collectable in this population. This pilot randomized feasibility trial addresses those uncertainties. Consistent with NCCIH PAR-25-274, it includes no efficacy aims, no hypothesis tests of clinical outcomes, and no effect-size estimation.

OBJECTIVES

Aim 1 (recruitment, randomization, retention, and equitable enrollment): to estimate the proportion of consecutively eligible cohort participants who accept randomization, the monthly recruitment rate, retention through the 12-week assessment, and the representation of racial and ethnic minority and publicly insured participants relative to the eligible pool.

Aim 2 (acceptability, adherence, fidelity, and safety): to estimate intervention adherence, protocol fidelity and clinical override rates when delivered by treating physical therapists other than the developer, and the frequency of PT-related adverse events, with surgical events ascertained in both arms; and to characterize acceptability of randomization, the intervention, the comparator, and study burden through qualitative interviews.

Aim 3 (assessment and data collection; protocol refinement): to estimate completion of the blinded assessment battery, completion of every-session patient-reported outcome administration, and completeness of 12-month passive EHR outcome and cost ascertainment; and to integrate all findings through a structured refinement process into a revised Manual of Procedures and a complete next-stage trial design.

Each aim has pre-specified quantitative feasibility benchmarks with green (proceed as designed), amber (proceed with pre-specified modification), and red (fundamental redesign required) thresholds.

STUDY DESIGN

Three-year, single-site, two-arm, parallel-group pilot randomized feasibility trial with blinded outcome assessment, embedded within an ongoing prospective observational VHR cohort at Thomas Jefferson University Hospital, Philadelphia, Pennsylvania. The design follows the cohort multiple randomized controlled trial (cmRCT) tradition, with one deliberate modification: consent to randomization is obtained before allocation rather than after, because acceptance of the randomization offer is itself a primary feasibility outcome. Sixty participants are randomized 1:1 to a tailored multi-component mind and body PT intervention plus usual care, or to usual care alone. Randomization occurs from Month 4 through Month 20; the last 12-week assessment is completed by Month 23; passive 12-month EHR ascertainment continues to data lock at approximately Month 32. The trial is reported according to the CONSORT 2010 extension for pilot and feasibility trials, SPIRIT, and COREQ.

SETTING

Thomas Jefferson University Hospital is a high-volume abdominal wall surgery referral center that performed 10,976 VHRs from 2019 to 2025. The source population is 14.2% non-Hispanic Black, 6.8% Hispanic or Latino, and 38.9% publicly insured. Five VHR surgeons perform an estimated 4 to 8 trial-eligible cases per week. Intervention sessions are delivered by nine treating physical therapists at six Jefferson Rehabilitation outpatient clinic sites.

ELIGIBILITY

Inclusion criteria: age 18 to 75 years; enrolled in the parent prospective VHR cohort; clinically or radiographically confirmed ventral hernia 4 to 10 cm undergoing elective primary or incisional (non-recurrent) repair; independent functional status; able to attend in-person PT sessions at a Jefferson Rehabilitation clinic; willing to be randomized, documented by separate randomization consent.

Exclusion criteria: PT within 30 days before VHR; history of or planned hernia-related botulinum toxin injection or component separation; neurologic disorder that would confound neuromuscular assessment or PT delivery; pregnancy.

RECRUITMENT AND CONSENT

Patients scheduled for elective VHR are enrolled pre-operatively in the parent observational cohort, whose consent discloses that an invitation to a randomized study may follow. At the two-week post-operative visit (T1), the research coordinator identifies every cohort participant who meets trial criteria and offers trial entry consecutively, with no investigator selection, using a standardized script and IRB-approved research-framed materials in English or Spanish. Participants who agree provide separate written randomization consent. Decline reasons are logged in pre-specified categories with the decliner's demographic and insurance characteristics. If the parent cohort is not funded, the identical protocol is activated as a standalone two-step consent under the trial's own IRB approval.

RANDOMIZATION AND ALLOCATION CONCEALMENT

Randomization is 1:1, stratified by sex and hernia type (primary versus incisional), using computer-generated permuted blocks of size 8 prepared by the study biostatistician before the first randomization and implemented in the REDCap randomization module. Allocation is concealed until the research coordinator executes randomization after documented consent and completion of the T1 blinded assessment. Treating physical therapists are notified of intervention-arm participants only. Outcome assessors have no access to allocation records.

INTERVENTION ARM: TAILORED MULTI-COMPONENT MIND AND BODY PHYSICAL THERAPY

Structure and dose. Following a two-week post-operative observation period with instructions identical to usual care, participants attend six in-person sessions at post-operative weeks 2, 4, 6, 8, 10, and 12, each 45 to 60 minutes, supplemented by a pathway-specific home program with practice logs reviewed each session. Sessions are grant-funded and delivered at no cost to participants.

Core mind and body components in every session. Regardless of pathway, every session includes diaphragmatic breathing retraining coordinated with abdominal wall activation, and biofeedback-guided motor retraining using rehabilitative ultrasound imaging of the abdominal wall or surface electromyography where pelvic floor activation is targeted.

Adaptive individualization. At the start of every session, the Oswestry Disability Index (ODI), STarT Back Screening Tool (SBT), Pelvic Floor Distress Inventory-20 (PFDI-20), and numeric pain rating scale are administered on a clinic tablet within a 15-minute check-in, and a manualized decision tree assigns the treatment pathway. Pathway 1, Symptom Modulation (ODI above 30%): low-intensity aerobic conditioning, thoracic, rib-cage, and lumbar mobilization, directional-preference exercise, and active rest instruction within abdominal wall healing precautions. Pathway 2, Movement Control (ODI 20 to 30%): flexibility exercise, transversus abdominis and oblique activation, motor control progression, and lumbopelvic stability training with load management. Pathway 3, Functional Optimization (ODI below 20%, not before 4 weeks post-operative): progressive endurance and strength training within surgeon-cleared lifting limits, task-specific training of patient-identified activities, and a written self-management plan.

Additive modules. Module A, impairment-based pelvic floor rehabilitation (PFDI-20 above 15), is delivered by a pelvic-health-trained physical therapist and includes pelvic floor muscle training with or without surface EMG biofeedback, manual therapy (external in the early phase; internal only after a separate consent conversation and confirmed wound healing, with a chaperone offered), bladder and bowel behavioral strategies, and pelvic-pain-tailored pain neuroscience education. Module B, psychologically informed pain neuroscience education, is delivered to participants at medium or high psychosocial risk on the SBT.

Load management. After any new exercise prescription, participants report symptoms through the patient portal at 24 to 48 hours, and the program is regressed one level if resting pain rises by 2 or more points.

Provider training and fidelity. All treating physical therapists complete eight hours of manualized training and pass a written competency assessment at 90% or higher before treating participants. Every session follows a five-block workflow documented on a structured checklist. With consent, a random 20% of sessions are audio-recorded and rated by an independent fidelity rater who is not the intervention developer; 10% of those are double-rated for inter-rater agreement. Any therapist below 75% concordance is retrained.

COMPARATOR ARM: USUAL CARE

Usual care is surgeon-directed post-operative management: abdominal binder, safe lifting technique, and graduated activity resumption, with PT referral left entirely to the treating surgeon's discretion as in current practice. No study-directed PT is provided. Control-arm participants may obtain PT through usual clinical channels; such co-intervention is not restricted but is tracked through the EHR and self-report as control-condition integrity data.

ASSESSMENTS

Blinded assessments are conducted at T1 (2 weeks post-operative, before randomization) and T2 (12 weeks post-operative) by two licensed physical therapists who have no treating role and no access to allocation, trained to an intraclass correlation of 0.80 or higher on all physical measures. Candidate measures, collected to determine completion rates, administration time, missing-data patterns, floor and ceiling behavior, and burden, include HerQLes (planned next-stage primary outcome), NPRS, SF-MPQ-2, PROMIS Pain Interference, ODI, SBT, PFDI-20, 6-Minute Walk Test, and 30-second Sit-to-Stand. Loaded core endurance testing (plank and single-leg bridge), infrasternal angle, and abdominal circumference are performed at T2 only, because loaded testing two weeks after mesh repair would violate abdominal wall precautions. At T2, assessors record a best guess of allocation as a blinding-integrity metric. Clinical outcomes (bowel obstruction, wound complication, recurrence or reoperation, new pelvic floor and spine diagnoses, emergency department visits, and rehospitalization) and total charges and estimated costs are abstracted passively from the EHR at 3, 6, and 12 months. All instruments have validated Spanish versions.

Acceptability interviews (n = 15 to 20) are conducted after T2 by the qualitative co-investigator with a purposive sample across arm, adherence level, and equity characteristics, including participants who declined randomization and consented to be interviewed.

FEASIBILITY BENCHMARKS (GREEN / AMBER / RED)

Randomization acceptance: 65% or higher / 50 to 64% / below 50%. Recruitment rate after a 3-month ramp-up: 3.5 or more per month / 2.5 to 3.4 / below 2.5. Retention through T2: 75% or higher / 60 to 74% / below 60%. Equitable enrollment, representation ratio (proportion among randomized divided by proportion among eligible cohort pool) for non-Hispanic Black and Hispanic or Latino participants and, separately, for Medicaid, dual-eligible, or uninsured participants: 0.80 or higher / 0.60 to 0.79 / below 0.60. Intervention adherence (5 or more of 6 sessions): 70% or higher / 50 to 69% / below 50%. Protocol fidelity: 80% or higher / 65 to 79% / below 65%. Clinical override rate: 20% or lower / 21 to 35% / above 35%. Assessment completion: 80% or higher of retained participants with complete T1 and T2 batteries and 85% or higher of attended sessions with complete ODI, SBT, and PFDI-20; amber within 10 points below; red more than 10 points below. EHR 12-month ascertainment: 80% or higher / 65 to 79% / below 65%. Safety: zero PT-related CTCAE Grade 3 or higher events (green); one event (immediate DSMB review); two or more events or any signal of excess surgical events in the intervention arm (red). Acceptability: no pervasive unacceptability theme for randomization, intervention, comparator, or burden.

SAMPLE SIZE

The sample size of 60 is justified by the precision of feasibility estimates, not by power for a clinical outcome. With n = 60, an observed retention of 75% carries a 95% confidence interval half-width of approximately 10 percentage points. With approximately 93 participants offered randomization, the acceptance-rate half-width is approximately 10 points. Fidelity and session-level assessment completion, estimated over approximately 180 intervention sessions, carry half-widths under 6 points. No sample size in this study is derived from, or will be used to derive, pilot outcome effect estimates.

ANALYSIS

All analyses are descriptive. Each feasibility outcome is reported as a point estimate with a 95% Wald confidence interval and classified green, amber, or red against the pre-specified cut-points. Recruitment is tracked on a monthly accrual dashboard; decline and attrition reasons are tabulated by demographic group; fidelity is summarized by therapist to expose clustering. Candidate clinical measures are summarized by arm and timepoint (means, standard deviations, medians, completion, missingness, floor and ceiling effects, and administration time) with no between-group hypothesis testing, no p-values, and no effect-size interpretation. Missingness is characterized as a feasibility outcome rather than imputed. Qualitative interviews are analyzed by directed content analysis within a biopsychosocial framework with inductive open coding, dual independent coding in NVivo, and inter-rater reliability assessed with Gwet's AC1. A structured refinement process integrates benchmark results, the protocol modification log, fidelity data, adverse event patterns, and qualitative findings into a revised Manual of Procedures and the next-stage trial design.

SAFETY MONITORING

Adverse events are graded per CTCAE v5.0 and logged in REDCap. Grade 2 events require program modification and notification within 48 hours; Grade 3 or higher events trigger immediate intervention cessation, surgical referral, and PI notification within 24 hours. Surgical events are ascertained in both arms at T2 and through 12-month EHR review. An independent three-member Data and Safety Monitoring Board, including a medical monitor who adjudicates relatedness to PT, meets at least twice yearly, reviews data at 25% and 50% enrollment, and has authority to modify or stop the trial.

PROGRESSION TO THE NEXT-STAGE TRIAL

Green results on every benchmark, including fidelity achieved by multiple independent therapists, support proceeding directly to a definitive multi-site efficacy trial. Amber results on any single element support a multi-site feasibility trial under NCCIH PAR-25-267 with that element redesigned. Red results on randomization acceptance or safety mean neither next step proceeds in its current form. Either outcome is decision-guiding.