A critical evaluation of the concomitant use of the implantable Doppler probe and the Vacuum Assisted Closure system in free tissue transfer

Negative Pressure Wound Therapy in Free Muscle Flaps-Risk or Benefit?

BACKGROUND

 Application of negative pressure wound therapy (NPWT) on free flaps not only reduces edema but also increases the pressure from outside. The impact of these opposite effects on flap perfusion remains elusive. This study evaluates the NPWT system's influence on macro- and microcirculation of free flaps and edema reduction to better assess the clinical value of this therapy in microsurgical reconstructions.

METHODS

 In this open-label, prospective cohort study, a total of 26 patients with free gracilis muscle flaps for distal lower extremity reconstruction were included. Flaps were covered with an NPWT (13 patients) or a conventional, fatty gauze dressing (13 patients) for 5 postoperative days (PODs). Changes in flap perfusion were analyzed by laser Doppler flowmetry, remission spectroscopy, and an implanted Doppler probe. Flap volume as a surrogate parameter for flap edema was evaluated by three-dimensional (3D) scans.

RESULTS

 No flap showed clinical evidence of circulatory disturbances. The groups showed significant differences in the dynamic of macrocirculatory blood flow velocity with an increase in the NPWT group and a decelerated flow in the control group from PODs 0 to 3 and PODs 3 to 5. No significant differences in microcirculation parameters were observed. 3D scans for estimation of edema development demonstrated significant differences in volume dynamics between the groups. Flap volume of the controls increased, while the volume in the NPWT group decreased during the first 5 PODs. The volume of NPWT-treated flaps decreased even further after NPWT removal from PODs 5 to 14 and significantly more than the flap volume in the control group.

CONCLUSION

 NPWT is a safe form of dressing for free muscle flaps that enhances blood flow and results in a sustainable edema reduction. The use of NPWT dressings for free flaps should therefore be considered not only as a pure wound covering but also as a supportive therapy for free tissue transfer.

Canadian Postoperative Dependency Protocols Following Lower Limb Microvascular Reconstruction: A National Survey and Literature Review

Introduction

Microsurgical free tissue transfer for lower limb reconstruction presents unique challenges in the postoperative period where dependency promotes interstitial fluid diffusion and reduced tissue perfusion. Management of flap edema, venous congestion, and ischaemic conditioning is critical for flap survival. Little evidence exists to guide postoperative protocols in the initiation and progression of lower extremity dangle, monitoring, and anticoagulation. We aim to describe current trends for postoperative dependency protocols by surveying Canadian microsurgeons.

Methods

Plastic surgeons performing lower limb microvascular reconstruction at Fellow of The Royal College of Surgeons of Canada approved teaching institutions were administered a 17-question anonymous electronic survey. A literature review was conducted to identify protocols and consensus opinions in other jurisdictions.

Results

All respondents (n = 16) monitored flaps clinically, with conventional Doppler used by 13 respondents. Anticoagulation was employed by 15 of 16 respondents, and 9 of 16 used 2 or more agents. The most common agents were aspirin, followed by low-molecular-weight heparin. Significant variability existed in dangling protocols. Dependency was initiated at postoperative day (POD) 3 to 10 (mean POD: 6 ± 1.64 standard deviation), with intervals ranging from 5 to 20 minutes and frequencies ranging from 1 to 6 times per day. Nearly half allowed both increasing duration and frequency of dependency. Flap success rates were above 90%, and the median length of stay was 10 to 12 days.

Conclusion

While flap success rates across the country are similar, no consensus exists for postoperative dependency protocols amongst Canadian microsurgeons. Prospective randomised controlled trials are warranted to evaluate early aggressive dependency protocols to reduce length of stay and cost.

Retrospective evaluation of diagnostic accuracy of free flap monitoring with the Cook-Swartz-Doppler probe in head and neck reconstruction

The Cook-Swartz-Doppler probe is an easy to handle and reliable tool for free flap monitoring. In the head and neck region different confounders can affect the read out. We therefore analyzed the use of the Doppler probe regarding these potential difficulties and to compare the diagnostic accuracy in arterial or venous monitoring of free flaps in the head and neck region. A retrospective study was performed in which all patients were included who underwent free flap surgery in the head and neck region in the Department of Plastic Surgery and the Department of Maxillofacial Surgery of our institution between 2010 and 2018 and were monitored with an implanted Doppler probe. 147 free tissue transfers were included. No significance was found for arterial and venous placement of the Doppler probe for sensitivity (artery 83.3%; vein 84.6%; p = 0.87), specificity (artery 89.2%; vein 96.1%; p = 0.17) and negative predictive value (artery 96.7%; vein 94.2%; p = 0.55). A better positive predictive value for placing the Doppler probe around the artery (82.7%) than the vein (61.1%) was found in our study (p = 0.056). The better positive predictive value in arterial monitoring suggests that this is the more reliable measuring method to assess flap perfusion in the head and neck region.

Microsurgical reconstruction of oncological scalp defects in the elderly

The incidence of scalp tumors requiring radical excision increases with age. Free flap surgery is the standard reconstructive option for large defects; however, there is an ongoing uncertainty about its safety in the elderly. We conducted a review of data and report on 19 patients aged ≥75 years and 13 < 75 years. Data regarding patient demographics, types of tumors, surgery, size of defect, flaps used, and prevalence of complications were analyzed. The patients in the elderly group had more accompanying medical conditions and a higher ASA score. Squamous cell carcinoma was the predominant tumor in the elderly and sarcoma in the younger patients. The defect size was similar in both groups. The latissimus dorsi (LD) and the anterolateral thigh (ALT) flaps were flaps of first choice, with temporal vessels most commonly used for anastomosis. Surgery lasted longer in the younger patients. There was no difference in the duration of hospital stay. No significant correlation was found between age and the flap-related or medical complications. Revision surgery was more often required in the younger patients. We conclude that free flap surgery is safe and reliable in the elderly population. The LD and the ALT are the most commonly used flaps. Advanced age should not be considered a risk factor for free flap surgery in these patients.

Salvage procedures after failed facial reanimation surgery using the masseteric nerve as the motor nerve for free functional gracilis muscle transfer

IMPORTANCE

Free muscle transfer innervated by a cross-facial nerve graft represents the criterion standard for smile reconstruction in facial paralysis. If primary reconstruction fails, a second muscle transfer is usually needed. Herein, we investigated the possibility of avoiding a second free muscle transfer by in situ coaptation of the gracilis muscle to the masseteric nerve.

OBSERVATIONS

We report a series of 3 failed free muscle transfers for facial reanimation among 21 free flap transfers performed for facial reanimation between March 2008 and August 2013. To salvage the muscle, we performed coaptation of the neural pedicle from the cross-facial nerve graft to the masseteric nerve. This method allows for leaving the fixation sutures of the muscle at the oral commissure in place. All patients showed muscle contraction after 3 months and a smile with open mouth after 6 months. No significant difference in the range of commissure excursion was observed between the healthy and operated sides.

CONCLUSIONS AND RELEVANCE

Recoaptation of the neural pedicle from the cross-facial nerve graft to the masseteric nerve, leaving the muscle transplant in place, is a suitable salvage procedure after unsuccessful reconstruction with a cross-facial nerve graft, avoiding a second free muscle transfer.

LEVEL OF EVIDENCE

4.

Single-stage dynamic reanimation of the smile in irreversible facial paralysis by free functional muscle transfer

Unilateral facial paralysis is a common disease that is associated with significant functional, aesthetic and psychological issues. Though idiopathic facial paralysis (Bell's palsy) is the most common diagnosis, patients can also present with a history of physical trauma, infectious disease, tumor, or iatrogenic facial paralysis. Early repair within one year of injury can be achieved by direct nerve repair, cross-face nerve grafting or regional nerve transfer. It is due to muscle atrophy that in long lasting facial paralysis complex reconstructive methods have to be applied. Instead of one single procedure, different surgical approaches have to be considered to alleviate the various components of the paralysis. The reconstruction of a spontaneous dynamic smile with a symmetric resting tone is a crucial factor to overcome the functional deficits and the social handicap that are associated with facial paralysis. Although numerous surgical techniques have been described, a two-stage approach with an initial cross-facial nerve grafting followed by a free functional muscle transfer is most frequently applied. In selected patients however, a single-stage reconstruction using the motor nerve to the masseter as donor nerve is superior to a two-stage repair. The gracilis muscle is most commonly used for reconstruction, as it presents with a constant anatomy, a simple dissection and minimal donor site morbidity. Here we demonstrate the pre-operative work-up, the post-operative management, and precisely describe the surgical procedure of single-stage microsurgical reconstruction of the smile by free functional gracilis muscle transfer in a step by step protocol. We further illustrate common pitfalls and provide useful tips which should enable the reader to truly comprehend the procedure. We further discuss indications and limitations of the technique and demonstrate representative results.

Open fractures of the hand with soft tissue loss

The evaluation, initial treatment, and definitive reconstruction of open fractures of the hand with associated soft tissue loss are reviewed. Specific attention is given to the literature on open fracture antibiotic prophylaxis in the hand; the timing of bone and soft tissue reconstruction; and options for soft tissue coverage, including local, regional, and distant tissue transfer. Factors that have shown association with outcomes in these injuries are also discussed, and the authors' preferred management is summarized.

Negative pressure wound therapy reduces the ischaemia/reperfusion-associated inflammatory response in free muscle flaps

BACKGROUND

We recently established negative pressure wound therapy (NPWT) as a safe postoperative care concept for free muscle flaps; however, the molecular effects of NPWT on free muscle flaps remain elusive. Here we investigated the effects of NPWT on pathological changes associated with ischaemia/reperfusion injury in free flap tissue.

METHODS

From July 2008 to September 2010, 30 patients receiving skin-grafted free muscle transfer for defect coverage were randomly assigned to two treatment groups: In one group the skin-grafted free flap was covered by a vacuum dressing (NPWT); in the second group, flaps were covered by conventional petroleum gauze dressings (conv). Biopsies were taken intra-operatively prior to clipping of the pedicle and on postoperative day 5. Samples were analysed by immunohistochemistry for infiltration of inflammatory cells, real-time polymerase chain reaction (RT-PCR) for the analysis of expression levels of interleukin-1β (IL-1β) and tumour necrosis factor (TNF)-alpha as markers of inflammation. Histological samples were also examined for interstitial oedema formation, and apoptosis was detected by a terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay.

RESULTS

NPWT leads to a significantly reduced tissue infiltration of CD68 + macrophages and reduced expression of the inflammatory cytokines IL-1β and TNFα. None of these parameters was significantly elevated in the pre-ischaemic biopsies. Furthermore, NPWT reduced the interstitial oedema formation and the number of apoptotic cells in free flap tissue.

CONCLUSION

NPWT of skin-grafted free muscle flaps leads to a reduced inflammatory response following ischaemia/reperfusion, resulting in reduced oedema formation improving the microcirculation and ultimately reduced tissue damage. We thereby deliver new insight into the effects of NPWT.

Repair of severe composite tissue defects in the lower leg using two different cross-leg free composite tissue flaps

This article reports 2 cross-leg free composite tissue flaps for repairing the severe composite tissue defects in lower leg without suitable adjacent recipient vasculature for microvascular anastomosis. The osseous myocutaneous flap of ilium and tensor fascia lata pedicled with ascending branch of lateral femoral circumflex vessels and the osseous muscle flap of scapula and latissimus dorsi pedicled with subscapular vessels were performed, respectively, to reconstruct the bone and soft-tissue defects in the lower leg of 2 patients. Both donor vessels were the posterior tibial artery and great saphenous vein from the contralateral lower leg. The legs and the bone flaps were immobilized by an external fixator. The periods of pedicle division were 43 and 67 days, respectively, after transplantation. Both flaps survived after pedicle division and the patients regained the ability to walk. There were no such complications as joint stiffness or donor site morbidity except for a linear scar. The 2 cross-leg free composite tissue flaps were optional methods for salvaging limbs that were otherwise nonreconstructable. But the indication for cross-leg free-tissue flap should be limited strictly.

Evidence-based recommendations for the use of Negative Pressure Wound Therapy in traumatic wounds and reconstructive surgery: steps towards an international consensus

Negative pressure wound therapy (NPWT) has become widely adopted over the last 15 years and over 1000 peer reviewed publications are available describing its use. Despite this, there remains uncertainty regarding several aspects of usage. In order to respond to this gap a global expert panel was convened to develop evidence-based recommendations describing the use of NPWT. In this paper the results of the study of evidence in traumatic wounds (including soft tissue defects, open fractures and burns) and reconstructive procedures (including flaps and grafts) are reported. Evidence-based recommendations were obtained by a systematic review of the literature, grading of evidence, drafting of the recommendations by a global expert panel, followed by a formal consultative consensus development program in which 422 independent healthcare professionals were able to agree or disagree with the recommendations. The criteria for agreement were set at 80% approval. Evidence and recommendations were graded according to the SIGN (Scottish Intercollegiate Guidelines Network) classification system. Twelve recommendations were developed in total; 4 for soft tissue trauma and open fracture injuries, 1 for burn injuries, 3 for flaps and 4 for skin grafts. The present evidence base is strongest for the use of NPWT on skin grafts and weakest as a primary treatment for burns. In the consultative process, 11/12 of the proposed recommendations reached the 80% agreement threshold. The development of evidence-based recommendations for NPWT with direct validation from a large group of practicing clinicians offers a broader basis for consensus than work by an expert panel alone.

An overview of negative pressure wound therapy for the lower extremity

Since its introduction into the market, negative pressure wound therapy (NPWT), also known as topical negative pressure, has become an important adjuvant therapy for the treatment of many types of wounds. Surgeons and physicians of all subspecialties have adopted NPWT into their practices. NPWT has become a mainstay in the management of lower extremity soft tissue pathology, especially in patients with traumatic, diabetic, postsurgical, and peripheral vascular disease-associated wounds. This article reviews the background, currently understood mechanisms of action, applications, contraindications, reported complications, advantages, criticisms, and techniques in the lower extremity.