The purpose of this study is to evaluate incidence of complete epithelialization in stage 3 & 4 pressure ulcers using ACell products.

A three arm, parallel-design, randomized study comparing 2 experimental arms to a single control arm. The primary comparison will be Group 1 (MicroMatrix® and ACell Cytal™ Wound Matrix 2-Layer vs. Group 3 (NPWT) to determine if Group 1 is superior to Group 3. NPWT is the standard of care (SOC) for patients with Stage 3 or 4 pressure ulcers and is the active control arm for the study.

A secondary comparison will be conducted comparing Group 2 (MicroMatrix® and ACell Cytal™ Wound Matrix 2-Layer plus NPWT) vs. Group 3 (NPWT) to determine if Group 2 is superior to Group 3.

Inclusion Criteria:

1. Provision of signed and dated informed consent form by subject or legally authorized representative.

2. Stated willingness to comply with all study procedures and availability for the duration of the study.

3. Male or female patients that are ≥ 21 years of age.

4. Body Mass Index (BMI) <45.

5. At least one Stage 3 or 4 pressure injury (NPUAP Staging Guidelines) present at the Screening and/or Treatment Visit located in any of the following regions:

   1. Occipital
   2. Back
   3. Flank
   4. Upper Extremity

   i. Arm ii. Elbow iii. Wrist iv. Hand e. Sacral f. Hip g. Gluteal h. Ischial i. Lower Extremity i. Leg ii. Knee iii. Ankle iv. Heel v. Foot

6. Surface dimensions of pressure injury must be between 9 to 64 cm2 inclusive (as measured prior to treatment using a cm-scale ruler). The longest dimension must not exceed 10 cm; depth must not exceed 5 cm.

7. Wound must be >5 cm from the anus if colostomy not performed.

8. For lower extremity ulcers: Adequate arterial blood flow and perfusion near the site of the injury (the foot is warm to the touch and has palpable pulses), per Investigator judgement.

9. Confirmed pressure injury versus moisture-associated skin damage or friction injury.

10. Ability to maintain an intact occlusive dressing for 4-7 days with reinforcement without contamination of urine or stool.

11. Confirmed fecal (Colostomy) and/or urine incontinence (Foley) maintenance/management, if necessary.

12. Consent to off-loading (turns) from pressure sites a minimum of every 2 hours (if possible).

13. Consent to sharp debridement of necrotic tissue in the wound bed unless the wound has already undergone debridement within 5 days prior to the Treatment Visit.

14. For females of reproductive potential (defined as females ≤ 55 years of age): Negative pregnancy test required prior to surgical debridement per hospital procedures.

Exclusion Criteria:

1. Surgical treatment of pressure injury 30 days prior to the Treatment Visit and/or pressure injury in previously irradiated areas.
2. Inability to manage fecal and/or urine incontinence or patient refusal of its maintenance/management (as determined medically necessary). Patient may be rescreened and enrolled if urinary and/or fecal continence status or management change after failure to comply with requirement.
3. Allergy or hypersensitivity to materials in porcine-based study products (per subject report) or personal preference.
4. Currently treated for an active malignant disease.
5. Prior diagnosis of active malignant disease, and is less than 1 year disease-free.
6. History of malignancy within the wound.
7. Presence of any conditions that are contraindicated with NPWT.
8. Any condition associated with a wound healing abnormality (e.g.: connective tissue disorder or immune disorder).
9. Dermatologic comorbid disease (e.g., cutis laxa or collagen vascular disease).
10. Bleeding diathesis.
11. Patients with primary treatment ulcers from burns (from exposure to high heat) or venous leg ulcers. A patient may have concomitant non-pressure ulcers present in non-pressure ulcer treatment regions.
12. Received biological-based therapy in any pressure wound within 3 months of the Treatment Visit.
13. Severe or significant hypoalbuminemia (albumin <2.5 g/dL, and/or pre-albumin <5 mg/dL), or hypoproteinemia (protein <6 g/dL).
14. Moderate to severe anemia (Hgb <7 g/dL).
15. Severely uncontrolled diabetes mellitus (defined as HA1C >12%).
16. Subject report of concurrent participation in another clinical trial that involves an investigational drug or device that would interfere with this study.
17. Subject report of previous participation in other interventional wound healing clinical investigation within 60 days prior to the Screening Visit.
18. The subject has any physical or psychiatric condition that in the Investigator's opinion would warrant exclusion from the study or prevent the subject from completing the study

There is no plan to share individual participant data