🩹 CPT 13160 — Secondary Closure Of Surgical Wound Or Dehiscence, Extensive Or Complicated
Quick Reference
wRVU: 11.74 | Global Period: 090 | Assistant Payable: Yes | Bilateral Indicator: 0 Rule: CPT 13160 carries a 90-day global period, one of the longest in the integumentary repair series, reflecting the substantial complexity and increased complication risk associated with re-closing an extensively dehisced or contaminated surgical wound. Because this closure frequently occurs during the postoperative global period of the original surgery, modifier -58 (staged/planned) or modifier -78 (unplanned return, related) is almost always required to distinguish 13160 from services already bundled into the original procedure’s global package. The bilateral indicator of 0 reflects that this code is not defined by a paired anatomic structure and is reported once per wound regardless of body site laterality; assistant surgeon services are payable given the complexity of tissue mobilization and layered closure typically required.
📋 Clinical Description
CPT 13160 describes the secondary closure of a surgical wound that has become extensively dehisced or was intentionally left open at the time of the original operation due to contamination, infection risk, or clinical instability, and now requires definitive closure.1 Unlike the size-tiered simple, intermediate, and complex repair codes (12001-13153) that describe closure of fresh traumatic or surgical wounds based on measured length, 13160 is a single, non-tiered code that applies regardless of wound length — the code is instead defined by the complexity and extent of the reopening, debridement, and layered repair required to achieve closure.2 The procedure requires reopening or further preparation of the wound, debridement of non-viable or necrotic tissue, undermining of wound margins to mobilize tissue for tension-free approximation, and a layered closure technique addressing the subcutaneous, fascial, dermal, and epidermal planes as clinically indicated.1
This code sits distinctly apart from the anatomic-site-specific complex repair codes such as 13131, 13132, 13151, and 13152, because 13160 applies to any body region and is triggered by the clinical scenario of dehiscence or delayed primary closure rather than by anatomic location or measured wound length.2 A wound that dehisces after an abdominal laparotomy, an orthopedic incision, or a traumatic injury repair may all be candidates for 13160 provided the reclosure meets the complexity threshold of extensive or complicated secondary closure — simple re-approximation of a clean, minimally separated dehiscence without significant tissue work is more appropriately coded to the lower-intensity wound dehiscence treatment codes (12020-12021) rather than 13160.3 Documentation must clearly establish why the wound was not closed primarily (contamination, infection, tissue viability concerns, or a planned delayed closure), the extent of debridement performed, and the specific layered closure technique used, as these elements collectively distinguish 13160 from a routine wound care encounter.1
This procedure may be performed in the following clinical contexts:
- Post-laparotomy fascial dehiscence — A patient develops full-thickness dehiscence of a midline abdominal incision on postoperative day 7 following exploratory laparotomy; the surgeon returns the patient to the OR, debrides necrotic subcutaneous tissue, irrigates the wound bed, and performs layered closure with retention sutures through the fascia and skin.
- Delayed primary closure of a contaminated traumatic wound — A patient sustains a heavily contaminated open lower extremity wound from a farming accident that is initially irrigated and packed open due to infection risk; three days later, once the wound bed is clean, the surgeon performs debridement of residual non-viable tissue, undermining, and layered secondary closure.
- Infected surgical incision requiring reclosure — Following an orthopedic total joint procedure, the incision becomes superficially infected and partially dehisces; after a course of wound care and infection control, the surgeon debrides the wound edges and performs an extensive layered secondary closure once granulation tissue is adequate.
- Staged closure after damage control surgery — A trauma patient undergoes an initial damage control laparotomy with the abdomen left open; at a planned return to the OR days later, the surgeon performs debridement and definitive layered fascial and skin closure of the abdominal wound.
- Dehisced C-section or gynecologic surgical incision — A postpartum patient develops a dehisced Pfannenstiel incision with purulent drainage; after resolution of infection with wound care, the surgeon performs debridement of granulation and non-viable tissue followed by extensive layered secondary closure.
🔬 Anatomical & Procedural Considerations
| Variant | Mechanism | Key Notes |
|---|---|---|
| Fascial/Abdominal Wall Dehiscence Closure | Abdominal wall dehiscence involves separation of one or more layers — skin, subcutaneous fat, fascia, and occasionally peritoneum — often due to increased intra-abdominal pressure, poor tissue healing, or infection; closure requires debridement of the wound edges to healthy, well-vascularized tissue, followed by layered reapproximation using heavy retention sutures through the fascia to withstand tension and prevent recurrent dehiscence or evisceration. | This is among the highest-acuity applications of 13160 and is frequently performed emergently; when the dehiscence occurs within the global period of the original laparotomy and is directly related to that procedure, modifier -78 applies for an unplanned return to the OR. |
| Extremity/Traumatic Wound Secondary Closure | Extremity wounds requiring 13160 typically follow initial debridement and open wound management (e.g., after a crush injury, farm accident, or gunshot wound) where primary closure was deferred due to contamination or tissue viability concerns; secondary closure requires reassessment of tissue viability, further debridement as needed, undermining of skin edges, and layered closure once the wound bed is adequately prepared. | These cases frequently involve multiple prior debridement encounters (11042-11047) before definitive closure; NCCI bundling rules prohibit billing debridement separately for the same wound on the same date as the 13160 closure, so debridement performed at a prior, distinct encounter is billed separately from the day of definitive secondary closure. |
| Postoperative Incisional Dehiscence (Non-Abdominal) | Dehiscence of surgical incisions outside the abdominal wall — such as orthopedic, spinal, or plastic surgery incisions — follows similar principles of debridement and layered closure but is tailored to the specific tissue planes involved (e.g., periosteum and fascia for orthopedic wounds, or fascia and dermis for plastic surgery incisions); the complexity threshold is met when the closure requires more than simple re-approximation, typically involving debridement of infected or necrotic tissue and multi-layer repair. | Careful documentation distinguishing 13160 from a simple in-office wound dehiscence treatment (12020-12021) is essential — the operative note must describe debridement of non-viable tissue and a true layered closure technique, not merely replacement of a few skin sutures. |
Clinical Pearl
The defining documentation threshold for CPT 13160 is not wound length but the complexity of the closure process itself — the operative note must establish that the wound required reopening or further preparation, debridement of non-viable tissue, and a true layered closure across multiple tissue planes.1 A dehiscence that is simply re-approximated at the bedside with a few interrupted sutures and no debridement is more appropriately coded as 12020 or 12021 (treatment of superficial wound dehiscence); billing 13160 for a low-complexity re-closure is one of the most common overcoding errors identified on payer audit.3 Always document the reason the wound dehisced or was left open, the tissue viability findings, and the specific closure technique by layer to fully support this code.
✅ Procedure Includes
- Reopening or further preparation of the dehisced wound — Exploration and preparation of the wound bed to assess tissue viability and extent of separation is included in the global service for 13160.
- Debridement of non-viable tissue — Sharp or mechanical debridement of necrotic, infected, or devitalized tissue performed as part of the closure is bundled within 13160 when done for the same wound on the same date.
- Wound irrigation — Thorough irrigation to remove debris, bacteria, and residual contamination prior to closure is included and not separately billable.
- Undermining of wound margins — Mobilization of skin and subcutaneous tissue edges to reduce tension and facilitate tension-free approximation is a defining component of this code.
- Layered closure across multiple tissue planes — Closure of the subcutaneous, fascial, dermal, and epidermal layers as clinically indicated, potentially including retention sutures for high-tension closures, is included in the global service.
- Hemostasis — Intraoperative hemostasis achieved through electrocautery, ligation, or pressure is bundled within the global procedure.
- Local anesthesia administration — When performed under local or regional block by the operating surgeon, anesthesia administration is included and not separately reportable.
❌ Excludes / Do Not Report Together
| Code | Description | Relationship |
|---|---|---|
| 12020 | Treatment of superficial wound dehiscence; simple closure | Mutually exclusive based on complexity — 12020 applies to simple re-approximation of a superficial dehiscence without extensive debridement or layered closure, while 13160 requires substantially greater tissue work; the operative note determines which code accurately reflects the service performed. |
| 11042 | Debridement, subcutaneous tissue; first 20 sq cm or less | NCCI edits bundle debridement codes 11042-11047 with 13160 when performed on the same wound on the same date, as debridement is an inherent component of the secondary closure; debridement performed at a separate, prior encounter or on a distinctly different wound may be billed independently with appropriate documentation and modifier -59 or -XS. |
| 14001 | Adjacent tissue transfer or rearrangement, trunk, arms, legs; defect 10.1 sq cm to 30.0 sq cm | Per CMS NCCI Policy Manual Chapter 3, CPT codes 12001-13160 shall not be reported separately with adjacent tissue transfer codes 14000-14350 for the same lesion or injury; if tissue transfer is required for closure, that code subsumes the repair and 13160 is not separately reportable for the same wound. |
Bundling Alert
The 90-day global period for CPT 13160 bundles extensive postoperative care through day 90, including routine dressing changes, wound checks, and related E/M services; when 13160 is performed during the global period of the original surgery that led to the dehiscence, modifier -58 must be used if the return was planned or staged, and modifier -78 must be used if the return to the OR was unplanned but clinically related to the original procedure.4 Absent one of these modifiers, payers will deny the claim as bundled into the original procedure’s global surgical package. NCCI bundling further prohibits separate billing of debridement (11042-11047) or adjacent tissue transfer (14000-14350) codes for the same wound on the same date as 13160, and wound closure performed simply to gain or close surgical exposure for a deeper procedure (tendon, nerve, or vessel repair) is not separately reportable unless the closure itself required substantially greater and independently documented work.4
🌳 Code Tree — Surgery: Integumentary System — Repair (Closure)
CPT 12001-13160 Repair (Closure) — Integumentary System
│
├── 12001-12021 Simple Repair and Wound Dehiscence Treatment
│ ├── 12011 Simple repair, face/ears/eyelids/nose/lips/mucous membranes; 2.5 cm or less (Global: 010)
│ ├── 12020 Treatment of superficial wound dehiscence; simple closure (Global: 010)
│ └── 12021 Treatment of superficial wound dehiscence; with packing (Global: 010)
│
├── 13131-13133 Complex Repair — Forehead, Cheeks, Chin, Mouth, Neck, Axillae, Genitalia, Hands, Feet
│ ├── 13131 Complex repair; 1.1 cm to 2.5 cm (Global: 010)
│ └── 13132 Complex repair; 2.6 cm to 7.5 cm (Global: 010)
│
├── 13151-13153 Complex Repair — Eyelids, Nose, Ears, Lips
│ ├── 13151 Complex repair; 1.1 cm to 2.5 cm (Global: 010)
│ └── 13152 Complex repair; 2.6 cm to 7.5 cm (Global: 010)
│
└── ▶▶ 13160 ◀◀ Secondary closure of surgical wound or dehiscence, extensive or complicated ← YOU ARE HERE (Global: 090)💰 RVU & Reimbursement Profile
| Component | Value |
|---|---|
| Work RVU | 11.74 |
| Global Period | 090 |
| Bilateral Indicator | 0 |
| Assistant Surgeon | Payable |
| Co-Surgeon | Not applicable |
| Team Surgery | Not applicable |
| PC/TC Split | No (indicator 0 — procedure only) |
| Modifier -51 Exempt | No |
| Anesthesia | Local anesthesia bundled when performed by the surgeon; general or regional anesthesia separately reportable by the anesthesia provider when a formal anesthesia service is furnished |
Bilateral Billing Rules
CPT 13160 carries a bilateral indicator of 0, meaning the concept of bilateral billing does not apply in the traditional sense since the code describes closure of a specific dehisced or complicated wound rather than a paired anatomic structure.5 When a patient has multiple distinct dehisced wounds at separate sites requiring secondary closure at the same session, each wound is evaluated independently, and modifier -59 or -XS with clear documentation of the separate and distinct sites supports reporting the code more than once, subject to payer-specific policy on multiple procedure billing.
🏷️ Modifier Reference
| Modifier | Name | When to Apply |
|---|---|---|
| -RT | Right Side | Apply when the dehisced wound requiring secondary closure is located on a paired right-sided anatomic structure (e.g., right lower extremity incision); supports laterality tracking for payer claims processing. |
| -LT | Left Side | Apply for dehisced wounds on paired left-sided anatomic structures; use in conjunction with distinct-site documentation if bilateral wounds are both closed at the same session. |
| -22 | Increased Procedural Services | Append when the secondary closure requires substantially greater physician work than typically required for 13160 due to extreme wound complexity, unusual anatomic factors, or exceptionally extensive tissue involvement; documentation must quantify the additional work performed. |
| -58 | Staged or Related Procedure During Global Period | Apply when the secondary closure was planned or staged at the time of the original surgery — for example, a damage-control laparotomy with planned delayed abdominal closure; this modifier prevents denial as bundled into the original procedure’s global package. |
| -59 | Distinct Procedural Service | Use when 13160 must be unbundled from another code subject to an NCCI edit because the service was performed on a separate, distinct wound; robust documentation of the distinct anatomic site is required. |
| -78 | Return to OR — Related Procedure | Apply when the patient has an unplanned return to the operating or procedure room during the global period for a dehiscence directly related to the original surgery; this is one of the most frequently required modifiers for 13160 given how often this code follows a related prior procedure. |
| -79 | Unrelated Procedure During Global Period | Use when the secondary closure addresses a wound entirely unrelated to a different procedure’s global period, such as closure of a traumatic wound in a patient who is coincidentally within the global period of an unrelated surgery. |
| -80 | Assistant Surgeon | Apply when a qualified assistant surgeon actively participates in the secondary closure procedure; documentation must reflect the assistant’s specific role and contribution. |
| -XS | Separate Structure | Use as a more specific alternative to modifier -59 when 13160 is billed alongside another integumentary procedure performed on a clearly separate anatomic structure or organ; increasingly preferred by payers over generic modifier -59 for structural distinctness. |
🩺 Common ICD-10-CM Pairings
Primary Diagnosis Group
| ICD-10 | Description | HCC? | Notes |
|---|---|---|---|
| T81.31XA | Disruption of external operation (surgical) wound, not elsewhere classified, initial encounter | No | Primary pairing for dehiscence of a skin-level surgical incision; use the 7th character A for the encounter at which the secondary closure is performed as active treatment. |
| T81.32XA | Disruption of internal operation (surgical) wound, not elsewhere classified, initial encounter | No | Use when the dehiscence involves deeper layers such as fascia, as in abdominal wall dehiscence with fascial disruption; pairs strongly with high-complexity 13160 encounters requiring retention suture closure. |
| T81.4XXA | Infection following a procedure, initial encounter | Yes | Use as a co-diagnosis when the dehiscence is driven by or associated with a postoperative surgical site infection; this code carries HCC weight and should be documented with specificity regarding the infecting organism when identified, using an additional code from category B95-B97 if applicable. |
| L76.32 | Postprocedural dehiscence of skin and subcutaneous tissue following a procedure on the skin and subcutaneous tissue | No | Use specifically when the dehiscence follows a prior dermatologic or skin-directed procedure rather than a deeper surgical operation; distinguishes superficial postprocedural dehiscence from the broader T81.3- category. |
Secondary Group
| ICD-10 | Description | HCC? | Notes |
|---|---|---|---|
| T81.89XA | Other complications of procedures, not elsewhere classified, initial encounter | No | Use as a secondary diagnosis when a documented postoperative complication contributed to the need for secondary closure but does not fit more specific dehiscence or infection categories. |
| L76.82 | Other postprocedural complications and disorders of the skin and subcutaneous tissue | No | Use for additional postprocedural skin complications not otherwise specified that contributed to delayed or complicated wound closure. |
Etiology / Complication
| ICD-10 | Description | HCC? | Notes |
|---|---|---|---|
| E11.9 | Type 2 diabetes mellitus without complications | Yes | Frequently reported as a contributing comorbidity when diabetes impairs wound healing and contributes to dehiscence risk; carries HCC weight and should be coded with the highest level of specificity regarding diabetic complications if present. |
| Z48.815 | Encounter for surgical aftercare following surgery on the skin and subcutaneous tissue | No | May be reported as an additional code to reflect the aftercare nature of the encounter when the secondary closure is part of ongoing surgical aftercare rather than treatment of a new acute condition. |
Coding Specificity Reminder
ICD-10-CM requires precise distinction between disruption of an external (skin-level) versus internal (deeper fascial or organ-level) surgical wound, as this distinguishes T81.31XA from T81.32XA, and both require the appropriate 7th character (A for initial encounter, D for subsequent encounter, S for sequela).6 When infection is present, sequence the infection code appropriately per the documentation and consider an additional code identifying the specific infectious organism when known. Do not use parent or unspecified category codes when a more specific billable code is available; always verify the 7th character requirement for the T81 and S-category codes, as omission results in an invalid, non-billable code.
🏥 MS-DRG Considerations
CPT 13160 frequently drives MS-DRG assignment in the inpatient setting when a patient returns to the operating room during the same admission for extensive secondary wound closure following dehiscence, most commonly reflected in DRGs within MDC 9 such as 573 through 575 (Skin Graft and/or Debridement, with or without CC/MCC) depending on associated comorbidities and complications.7 When the dehiscence follows a major abdominal or orthopedic procedure during the same inpatient stay, the coder must evaluate whether the secondary closure is the primary driver of DRG assignment or a secondary OR procedure within a more complex overall admission; POA (present on admission) status is not applicable since the dehiscence, by definition, arises during the inpatient stay following the index procedure. Facility coders should also apply the appropriate complication or comorbidity (CC/MCC) designation for the underlying dehiscence and any associated infection diagnosis, as these frequently elevate DRG severity and reimbursement weight.
🔧 ICD-10-PCS Equivalents
| PCS Code | Full Description | Modality |
|---|---|---|
| 0HQ0XZZ | Repair Skin, Scalp, External Approach | Repair — Skin and Breast |
| 0HQ1XZZ | Repair Skin, Face, External Approach | Repair — Skin and Breast |
| 0HQ7XZZ | Repair Skin, Abdomen, External Approach | Repair — Skin and Breast |
| 0HQBXZZ | Repair Skin, Right Upper Arm, External Approach | Repair — Skin and Breast |
PCS Character Analysis (Example using 0HQ7XZZ — Repair Skin, Abdomen, External Approach)
| Position | Character | Value | Definition |
|---|---|---|---|
| 1 | Section | 0 | Medical and Surgical — indicates a surgical procedure performed directly on a body part. |
| 2 | Body System | H | Skin and Breast — the body system encompassing the integumentary structures targeted by secondary closure. |
| 3 | Root Operation | Q | Repair — restoring a body part to its normal anatomic structure and function to the extent possible; correct for secondary wound closure when no substitute tissue is placed and no body part is transferred. |
| 4 | Body Part | 7 | Skin, Abdomen — specifies the abdominal skin as the site of the dehisced wound requiring closure. |
| 5 | Approach | X | External — performed directly on the skin surface without incision to access a deeper structure, appropriate for external wound reclosure. |
| 6 | Device | Z | No Device — no implant, graft, or hardware remains in place following the procedure. |
| 7 | Qualifier | Z | No Qualifier — no additional qualifying descriptor applies to this procedure. |
Root Operation Comparison
- Repair (Q) is the correct root operation for CPT 13160 equivalents because the objective is to restore the wound to a closed, anatomically intact state — appropriate for debridement-and-layered-closure procedures without device placement or tissue substitution.
- Extirpation (C) may apply as an additional or separately coded procedure if extensive foreign material or necrotic debris is physically removed from the wound prior to closure and the facility’s coding policy requires separate capture of that removal.
- Replacement (R) would apply only if a biological or synthetic substitute (e.g., mesh, acellular dermal matrix) is placed to reconstruct the wound during closure — not applicable to standard secondary closure without such material, in which case the coding would shift to a device-containing PCS code rather than the no-device Repair code shown above.
📝 Coding Examples
Example 1
Clinical Scenario: A 58-year-old male develops full-thickness dehiscence of a midline abdominal incision on postoperative day 8 following an exploratory laparotomy for bowel obstruction performed by the same surgeon. The surgeon returns the patient to the OR, reopens the wound, debrides necrotic subcutaneous tissue and devitalized fascia margins, irrigates extensively, and performs layered closure of the fascia with heavy retention sutures and the skin with staples.
| Field | Code | Rationale |
|---|---|---|
| CPT | 13160--78 | Extensive secondary closure with debridement and layered fascial and skin repair; modifier -78 required because this is an unplanned return to the OR during the global period of the original laparotomy for a complication (dehiscence) directly related to that procedure. |
| PDx | T81.32XA | Disruption of internal operation (surgical) wound, not elsewhere classified, initial encounter — reflects the fascial-level dehiscence requiring deep layered repair. |
Note
Modifier -78 reimburses only the intraoperative portion of the procedure since the patient remains within the global period of the original surgery; the operative note must explicitly document that the dehiscence is related to the prior laparotomy and describe the debridement and layered closure technique in detail to support the complexity of 13160 over a lower-intensity dehiscence treatment code.4
Example 2
Clinical Scenario: A 34-year-old female with a farm-related crush injury to the left lower leg initially undergoes irrigation and debridement with the wound left open due to gross contamination. Five days later, once the wound bed demonstrates healthy granulation tissue on serial wound checks, the surgeon performs debridement of residual non-viable tissue, extensive undermining of the skin edges, and layered secondary closure at a planned, staged return to the OR that was documented at the time of the initial procedure.
| Field | Code | Rationale |
|---|---|---|
| CPT | 13160--58--LT | Extensive secondary closure of a contaminated traumatic wound with debridement, undermining, and layered closure; modifier -58 applies because the staged return was planned at the time of the initial debridement procedure, and modifier LT specifies the left lower extremity. |
| PDx | T81.31XA | Disruption of external operation (surgical) wound, not elsewhere classified, initial encounter — reflects the delayed primary closure scenario following initial wound management. |
Warning
Debridement performed at this same encounter for the same wound is not separately billable per NCCI bundling rules — only debridement performed at the earlier, distinct encounter when the wound was initially managed is separately reportable; billing debridement again on the date of definitive closure for the same wound will trigger an NCCI PTP edit denial.4
Example 3
Clinical Scenario: A 46-year-old female develops a superficial surgical site infection with partial dehiscence of a Pfannenstiel incision two weeks after a cesarean section performed at a different facility by a different surgeon. After a course of outpatient wound care and oral antibiotics, the current surgeon debrides granulation tissue and non-viable wound margins in the office and performs an extensive layered secondary closure under local anesthesia.
| Field | Code | Rationale |
|---|---|---|
| CPT | 13160 | Extensive secondary closure of a dehisced, previously infected surgical incision; no modifier 58/78 is required because the surgeon performing the closure is different from the original surgeon and this is not within that surgeon’s own global period. |
| PDx | T81.31XA | Disruption of external operation (surgical) wound, not elsewhere classified, initial encounter — primary diagnosis reflecting the dehisced incision. |
Global period reminder
When the physician performing the secondary closure is not the same physician (or same-group physician) who performed the original surgery, that new physician is not bound by the original procedure’s global period and modifiers 58/78/79 are not required; however, the new physician’s own 90-day global period for 13160 begins on the date of this closure and bundles subsequent related postoperative care.4
⚠️ Common Coding Pitfalls
- Pitfall 1 — Billing 13160 for simple dehiscence re-approximation: When a dehiscence is superficial, clean, and requires only minimal re-suturing without debridement or true layered closure, the correct code is 12020 or 12021, not 13160; billing 13160 for a low-complexity closure is a common overcoding error that will be identified on audit if the operative note does not support the required complexity elements.
- Pitfall 2 — Missing modifier -58 or -78 during the original surgeon’s global period: When the same surgeon (or same-group physician) who performed the original procedure also performs the secondary closure within that procedure’s global period, failure to append modifier -58 (planned/staged) or -78 (unplanned, related) will result in automatic denial as bundled into the original global surgical package.
- Pitfall 3 — Separately billing debridement for the same wound on the same date: NCCI edits bundle debridement codes 11042-11047 with 13160 when performed on the same wound at the same encounter; debridement is only separately billable when performed on a clearly distinct, separate wound with modifier -59 or -XS and independent documentation.
- Pitfall 4 — Billing 13160 alongside adjacent tissue transfer for the same wound: Per NCCI Chapter 3, codes 12001-13160 are not separately reportable with adjacent tissue transfer codes 14000-14350 for the same lesion or injury; if a flap or tissue rearrangement is ultimately required, that code subsumes the closure and 13160 should not be reported concurrently for the same wound.
- Pitfall 5 — Failing to document the reason for delayed or secondary closure: The operative note must state why the wound was not closed primarily (contamination, infection, tissue viability, or planned staged closure); omitting this rationale weakens the clinical justification for the complexity of 13160 and increases audit vulnerability.
- Pitfall 6 — Reporting 13160 as inherent wound closure for a deeper procedure: When wound closure is performed simply to close surgical exposure after a tendon, nerve, or vessel repair, that closure is included in the primary procedure code and is not separately reportable as 13160 unless the closure itself required substantially greater, independently documented work beyond what the primary procedure entailed.