Mini-ID – A minimally invasive drainage strategy for complicated skin and soft tissue infection

Abstract

Rationale:

Complicated skin and soft tissue infections (cSSTIs) are severe infections that may arise from abscesses, cellulitis, fasciitis, diabetic foot infections, trauma-related infections, and surgical site infections. Conventional treatment typically requires surgical drainage combined with systemic antibiotics. However, exploratory surgical drainage may cause tissue damage and increase inflammatory responses.

Patient concerns:

A 35-year-old male with diabetic ketoacidosis presented with progressive swelling, erythema, and pain in the right upper arm despite prior antibiotic therapy.

Diagnosis:

Complicated skin and soft tissue infection with localized abscess formation.

Interventions:

After the patient was stabilized and was treated using a minimally invasive sequential management strategy termed Mini-ID, which consists of minimal drainage, infection control, inflammation control, and adequate debridement. Drainage was performed using a skin biopsy punch instrument to minimize tissue damage. Culture-guided antibiotic therapy was subsequently administered.

Outcomes:

The patient demonstrated rapid clinical improvement with a significant reduction in inflammatory markers and complete wound healing at 3 months without requiring extensive surgical intervention.

Lessons:

The Mini-ID approach emphasizes that adequate source control rather than the extent of surgical incision may be sufficient in selected cSSTI cases. This strategy may reduce tissue injury and inflammatory burden while maintaining clinical effectiveness.

1. Introduction

Skin and soft-tissue infections (SSTIs) are among the most common bacterial infections observed in clinical practice.^[1] SSTI encompasses a broad clinical spectrum, including abscesses, cellulitis, fasciitis, diabetic foot infections, trauma-related infections, and surgical site infections. These infections may involve different anatomical layers including the epidermis, dermis, subcutaneous tissue, fascia, and muscle.^[2]

Complicated skin and soft tissue infections (cSSTIs) represent the more severe end of the SSTI spectrum and frequently occur in patients with underlying comorbidities such as diabetes mellitus or immunocompromised conditions.^[2]

For cSSTI patients, the standard of care is etiological pathogen culture, systemic antibiotics, and source control with surgical drainage or debridement.^[3] Although surgical drainage is an essential component of source control, exploratory incision may cause significant tissue damage and expose critical structures such as tendons or bones. Moreover, premature closure of the drainage opening and incomplete drainage are common limitations of conventional linear incisions. These injuries may increase the risk of secondary infection and complicate subsequent wound reconstruction.

Recent understanding of inflammatory responses suggests that tissue injury can lead to the release of damage-associated molecular patterns (DAMPs), which amplify inflammatory cascades and may impair wound healing. Similarly, pathogen-associated molecular patterns (PAMPs) derived from microorganisms activate innate immune responses through pattern recognition receptors.

To address these challenges, we propose a minimally invasive management strategy termed Mini-ID, which emphasizes minimal drainage wound opening, infection control, inflammation control, and adequate debridement. This article presents a clinical case illustrating the application of the Mini-ID protocol in the management of complicated SSTI.

The study protocol was approved by the Institutional Review Board of Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, prior to study initiation. Written informed consent was obtained from the patient for participation.

2. Case report

A 35-year-old male with newly diagnosed type II diabetes mellitus presented with progressive swelling, erythema, and pain over the right upper arm for approximately 2 weeks. The patient had initially received oral antibiotic therapy at a local clinic; however, the infection continued to worsen, leading to hospital admission. Empirical broad-spectrum antibiotics were started based on clinical severity and local antimicrobial guidelines.

On physical examination, a tender, fluctuant mass was noted over the right upper arm, accompanied by localized warmth and fever, suggesting a complicated skin and soft tissue infection (Fig. 1A). At admission, laboratory data revealed a leukocyte count of 23.52 × 10³/μL with significant bandemia (34%) and a markedly elevated C-reactive protein (CRP) level exceeding 380 mg/L, consistent with a severe systemic inflammatory response.

Figure 1.

Surgical management of complicated skin and soft tissue infection of the right upper arm using a punch biopsy technique. (A) Preoperative clinical presentation showing diffuse swelling and erythema of the right upper arm, suggestive of underlying fluid accumulation and inflammation. (B) Axial computed tomography image of the right upper arm demonstrating soft tissue swelling with subcutaneous fat stranding and a suspected deep-seated fluid collection (arrow), consistent with fasciitis involving the deep fascial planes. (C) Post-procedural appearance following drainage using a punch biopsy instrument. Reduction in swelling is observed, with a small circular drainage site indicating the location of the minimally invasive intervention.

In addition, metabolic evaluation revealed severe hyperglycemia, with a random blood glucose level of 494 mg/dL and an HbA1c of 13.5%, indicating poorly controlled and likely long-standing diabetes mellitus. Urinalysis demonstrated significant glucosuria (4+) and ketonuria (3+), while serum ketone levels were elevated (4.2 mmol/L). Arterial blood gas analysis showed metabolic acidosis, with decreased bicarbonate (HCO₃⁻ 13.1 mmol/L) and base excess of − 13.1 mmol/L, consistent with diabetic ketoacidosis precipitated by severe infection.

A computed tomography (CT) scan of the right upper arm was performed. Axial images demonstrated significant soft tissue swelling, characterized by increased attenuation and prominent reticular fat stranding within the subcutaneous layer, suggestive of extensive cellulitis or soft tissue inflammation (Fig. 1B). Given the persistent infection and lack of clinical improvement despite initial antibiotic therapy, the patient underwent treatment using the Mini-ID protocol (Fig. 1C).

Under general anesthesia, the procedure was executed through a structured, sequential protocol designed to minimize surgical trauma while ensuring optimal source control:

• Identify maximal fluid collection: The localized fluid cavity was precisely mapped to determine the optimal entry point.

• Create a precise circular punch opening: A 4-mm skin biopsy punch was utilized to create a clean, non-collapsing circular opening directly over the area of maximal collection to facilitate continuous drainage.

• Remove necrotic tissue minimally when necessary: Limited debridement of nonviable tissue beneath the skin envelope was performed using a curette, effectively reducing the local bacterial burden while strictly preserving the surrounding viable tissue architecture.

• Irrigate the cavity thoroughly: The wound cavity was status-post cleared via thorough irrigation with 100 mL of hypochlorous acid solution.

• Maintain continuous drainage: The circular configuration of the punch opening was maintained patently to allow sustained, unhindered evacuation of purulent discharge without premature closure.

Immediately after minimal drainage through the punch-created opening, purulent material was obtained for microbiological culture prior to the initiation of definitive antibiotic therapy whenever feasible. Wound culture grew methicillin-sensitive Staphylococcus aureus, resistant to penicillin and susceptible to oxacillin and methicillin. Antibiotic treatment was then tailored according to culture and susceptibility results.

Following the Mini-ID procedure, the patient demonstrated gradual clinical improvement, including reduction of local inflammation, decreased purulent drainage, and progressive wound healing (Fig. 2A). Serial laboratory evaluation showed a substantial reduction in inflammatory burden. By postoperative day 12, the leukocyte count had decreased to 13.51 × 10³/μL, and CRP had declined to 68.85 mg/L, representing a reduction of more than 80% from baseline. Differential count demonstrated resolution of bandemia with a predominance of segmented neutrophils, suggesting recovery from acute infection. Additionally, a reactive increase in platelet count (from 291 to 546 × 10³/μL) was observed, consistent with the inflammatory recovery phase. Concurrently, metabolic derangements improved with glycemic control and supportive care.

Figure 2.

Postoperative clinical course following minimally invasive drainage of complicated skin and soft tissue infection of the right upper arm. (A) Clinical appearance of the right upper arm 2 weeks after the procedure, demonstrating marked reduction in swelling and inflammation with ongoing wound healing. Residual periwound inflammation with focal superficial skin sloughing was noted (arrow). (B) Complete wound healing at three-month follow-up, with no evidence of residual infection or recurrence. The resulting scar demonstrated a satisfactory aesthetic appearance.

During a three-month follow-up period, the infection resolved without the need for extensive surgical incision. No recurrence was observed during follow-up (Fig. 2B).

3. Discussion

This case suggests that effective source control can be achieved with a minimally invasive drainage strategy in carefully selected patients with localized cSSTI, avoiding the need for extensive surgical incisions. The favorable healing trajectory and cosmetic outcome observed in this patient reflect the core principle underlying the framework: that adequacy of source control, rather than extent of surgical intervention, is a key determinant of clinical success in appropriately selected cases.

Ideal candidates for this minimally invasive approach are stable patients presenting with localized abscesses and well-defined fluid collections, in the strict absence of extensive tissue necrosis or rapidly progressive necrotizing infections. Conversely, Mini-ID is not intended to replace aggressive surgical intervention when clinically indicated; patients presenting with diffuse necrosis, compartment syndrome, or necrotizing soft tissue infections must immediately undergo conventional open surgical debridement to achieve adequate source control.

Effective drainage not only removes purulent collections but also decreases the local burden of PAMPs and DAMPs, thereby reducing persistent inflammatory signaling and facilitating tissue repair. The pathophysiological basis for this approach lies in PAMPs and DAMPs. PAMPs are found on the surface of pathogens, such as bacteria, that can trigger innate and cell-mediated immune responses.^[4] DAMPs, conversely, are released from damaged or dying tissues and cells, such as nucleic acids, heat shock proteins, and intracellular enzymes.^[5] This pathophysiological framework supports a minimally invasive surgical strategy that limits tissue disruption while achieving effective source control.

The first step in the proposed Mini-ID approach for the management of cSSTI is adequate drainage through carefully selected position and controlled incisions. Instead of performing an exploratory incision for drainage of purulent material and abscess cavities, a skin biopsy punch instrument is used to create a precise circular opening. This tool allows accurate control of incision depth and produces a defined circular drainage site rather than a linear surgical incision. Because the wound edges are not tightly approximated, the risk of premature closure is minimized, allowing continuous drainage of infected material.

Punch size selection is determined according to the characteristics and depth of the infected cavity. A 2-mm punch biopsy can be used for superficial drainage, and the biopsy wound typically heals within approximately 1 week. A 4-mm punch is suitable for moderate abscess collections requiring more effective evacuation of purulent material, although the biopsy site may require a longer healing period of up to 1 month. For deeper infections, including suspected compartment or muscle abscesses, a 6-mm punch may be used to facilitate adequate drainage, and sutures may be required for wound closure.

The goal of Mini-ID is to minimize tissue injury while maintaining adequate drainage and effective source control. By minimizing unnecessary tissue disruption, this strategy may reduce the release of excessive DAMPs from injured tissues. This approach helps preserve surrounding tissue integrity and may contribute to improved wound healing outcomes.

Conventional open exploratory surgeries carry an inherently higher likelihood of extensive tissue and cell damage, which subsequently triggers the release of an excessive burden of DAMPs from the injured host tissues.^[6] These DAMPs can stimulate the immune system and trigger an inflammatory response, which can affect postoperative recovery and treatment outcomes. Some studies suggest that reducing the release of DAMPs can alleviate the postoperative inflammatory response and tissue damage and promote wound healing and recovery.^[6] By restricting the entry to a precise 4-mm punch and avoiding wide linear incisions, the Mini-ID strategy preserves the integrity of the surrounding viable tissue architecture, reduces the secondary systemic or local release of DAMPs, and lessens the overall inflammatory burden. Consequently, this mitigation of the prolonged inflammatory phase helps maintain tissue viability and directly contributes to an accelerated, improved wound healing outcome.

Effective infection control also requires appropriate antimicrobial therapy targeted toward the causative pathogen. The Infectious Diseases Society of America recommends obtaining bacterial cultures to guide antibiotic selection in patients with severe infection, nonresponsiveness to empirical therapy, or recurrent infection.^[7] Early identification of the causative organism and timely initiation of appropriate antibiotics may rapidly reduce microbial burden, decrease PAMP levels, and improve clinical outcomes. Failure to select appropriate antimicrobial therapy in cSSTI has been associated with increased treatment failure, higher mortality rates, prolonged hospitalization, and increased risk of readmission.^[8]

Inflammation control also plays an important role in wound healing. Several systemic inflammatory diseases – including rheumatoid arthritis, systemic lupus erythematosus, and neurodegenerative conditions such as Alzheimer’s disease – are associated with dysregulated inflammatory responses.^[9] Excessive or prolonged inflammation may impair tissue regeneration, whereas effective modulation of inflammatory responses has been associated with improved healing outcomes.^[10,11]

Debridement of necrotic tissue lowers the wound’s bioburden, and the concentration of PAMP subsequently decreases.^[10] Adequate debridement should be emphasized because extensive debridement may lead to tissue damage, vital structure exposure, and a surge in DAMP. This measured strategy seeks to balance the need for infection control with the potential risks of extensive debridement.

Although the Mini-ID approach aims to achieve effective source control through minimal drainage, conversion to conventional surgical drainage should be considered when clinical improvement is not observed. Escalation to a more extensive surgical intervention may be considered in the presence of persistent fever or systemic inflammatory response, progressive local infection or enlargement of the abscess cavity, development of tissue necrosis, or failure of infection control within 48–72 hours following the initial procedure. In such circumstances, conventional incision and drainage or more extensive surgical debridement should be performed to achieve adequate source control and prevent further progression of the infection, as shown in Figure 3.

Figure 3.

Mini-ID protocol for complicated skin and soft tissue infections. This flowchart illustrates a stepwise clinical decision-making algorithm integrating the Mini-ID strategy for the management of cSSTI. Initial assessment identifies surgical emergencies (e.g., necrotizing fasciitis, deep infection, instability, compartment syndrome) requiring conventional surgery. Eligible non-emergent cases undergo Mini-ID, based on localized infection, tissue necrosis, and stability. The protocol uses punch-based minimal drainage (2–6 mm) with debridement and infection control. Empirical antibiotics are started after culture and adjusted per results. Reassessment occurs at 48 to 72 h; lack of improvement prompts repeat Mini-ID or surgery. Improved cases receive ongoing wound care and follow-up at 3–5 d and 1–2 wk. This approach ensures effective source control while minimizing tissue damage and inflammation.

Post-procedural pain is generally mild and can be managed with standard oral analgesics when necessary. Wound care includes gentle irrigation of the drainage site with normal saline or hypochlorous acid solution, application of absorbent dressings to allow continuous drainage, and regular inspection of the wound to monitor for signs of infection progression.

Following the Mini-ID procedure, patients should undergo regular clinical follow-up to evaluate infection control and wound healing progression. Initial reassessment is recommended within 48–72 hours to ensure adequate drainage and clinical improvement. Subsequent follow-up at 3–5 days allows evaluation of wound condition and dressing management, while additional follow-up at 1–2 weeks is useful for assessing healing progression and detecting any signs of recurrent infection (Fig. 3). Clinical infection parameters and wound status are monitored at approximately 3-day intervals during the early treatment period. Further follow-up may be arranged according to the severity of infection and the patient’s overall clinical condition.

Contraindications to the Mini-ID approach include infections that are excessively deep and unlikely to be adequately drained using punch drainage, as well as extensive infections in patients with uncontrolled underlying diseases or severely compromised general conditions. Conditions requiring immediate surgical exploration, such as necrotizing fasciitis, compartment syndrome, or abscesses located in deep anatomical spaces (e.g., retroperitoneal abscess), should be managed with conventional surgical drainage rather than minimal drainage strategies.

Several limitations should be acknowledged in this study. As this report describes a single clinical case, future prospective studies incorporating standardized patient selection criteria, biomarker monitoring, and comparative outcome analyses against conventional surgical drainage will be necessary to further evaluate the effectiveness and reproducibility of this approach. To validate the efficacy, safety, indications, and long-term outcomes of the Mini-ID framework across different patient populations, establishing a multicenter registry of cSSTI cases managed with punch drainage represents a practical and necessary first step toward prospective validation.

4. Conclusion

In conclusion, the Mini-ID protocol provides a minimally invasive strategy for the management of complicated skin and soft tissue infections in selected patients. By combining controlled drainage, appropriate antimicrobial therapy, inflammation control, and measured debridement, this framework aims to achieve effective infection control while preserving surrounding tissue integrity. Although limited to a single case, these findings suggest that Mini-ID may be a useful adjunctive drainage strategy that warrants further clinical investigation. Further clinical studies are needed to determine its broader applicability.

Acknowledgments

The authors used ChatGPT (OpenAI) to assist with language editing and refinement of the manuscript. All content was reviewed, validated, and approved by the authors, who take full responsibility for the final manuscript and its compliance with publication ethics.

Author contributions

Data curation: Patrick Szu-Ying Yen, Hou-Yuen Tong.

Formal analysis: Patrick Szu-Ying Yen.

Writing – original draft: Patrick Szu-Ying Yen.

Writing – review & editing: Patrick Szu-Ying Yen.

Methodology: Chao-Wei Chang, Yun-Nan Lin.

Resources: Yun-Nan Lin.