Short Notes in Plastic Surgery

June 19, 2019

6A. Vacuum Assisted Closure

Filed under: Chapter 6A — ravinthatte @ 5:06 am

6A. Vacuum Assisted Closure

(Also popularly called by its short form VAC)

Introduction

When this blog was begun in 2011, Vacuum Assisted Closure or VAC as an aid in improving the quality of wounds as well as their preparation for final closure with a suitable skin cover was just about making its presence felt in Indian hospitals. In fact, there was an official presentation on the technique in the annual meeting of the association of plastic surgeons of India in Goa where that meeting was held in the year 2010. Since then VAC has come to be accepted as a routine technique for preparation of wounds prior to their closure or cover by skin grafts or flaps. In fact, the technique is also used after a skin graft is applied and has shown good results in the “take” of the grafts because the suction that the VAC machine employs increases the force with which the graft comes to oppose the recipient area and an elaborate “tie over” dressing is not required to eliminate the possibility of the graft shearing away from the recipient area. In view of this background this small chapter is being added to the section on skin grafting for which Dr. Parag Sahasrabudhe the head of the department of plastic surgery at the Sassoon General Hospital in Pune, Maharashtra, India was invited to contribute. The compiler of these “Short Notes” thanks him and his colleague Dr. Amey Bindu for their efforts. The compiler of these short notes also thanks Dr. Sitaram Prasad and Dr. Shailesh Ranade of Mumbai India for providing suitable illustrations for this chapter.  

History

That wounds improve by being sucked was known in ancient times and Ayurvedic texts of ancient Indian medicine around and before the Christian era describe an appliance called GHATI YANTRA in the form of a cup (probably an earthen ware) which was heated prior to application around the wound and later had a sucking effect on the wound as it cooled and settled down to the ambient temperature.

During the Roman empire the wounds suffered by its soldiers were routinely sucked by mouth by other men and some of them were proficient enough in this art and were called to perform the act routinely. In the story of Cleopatra who was bitten by a poisonous snake (an Asp) such a professional “sucker” was supposed to have been commissioned but the treatment did not succeed and Cleopatra succumbed to the Asp’s bite.

In the eighteenth and nineteenth century cupping to improve wounds was quite common and one such cup was called the “leech cup” in England to indicate that the cup was doing the same thing that leeches did when they sucked the periphery of the wounds to reduce oedema. In fact, the deity associated with Ayurved (Dhanwantari) has a leech in one of its many hands.

The modern history of mechanical suction of wounds begins in Afghanistan in 1985 when Bagaoutidinov, a Russian surgeon used a mechanical suction machine to treat wounds suffered by Russian soldiers injured in the Russo- Afghan war.

However, the real beginning to the formal description and use of a suction machine with the help of polyurethane non-absorbent foam and tubes must be credited to Drs. Louis Argenta and Michael Morikwas from the Wake Forest School of Medicine in North Carolina, USA in 1990.  

Nomenclature and principles

The principle of the technique is to seal the periphery of the wound with a barrier then apply a sheet of poly urethane foam of the size of the wound and then cover it with a transparent film. A drainage tube is then placed over the foam through this film and the other end of the tube is attached to a suction cannister with a negative pressure between 80 and 125 mms of mercury. This system also goes by the name ‘negative pressure wound therapy (NPWT)’ Topical negative pressure (TNP) or Vacuum sealing technique

How does VAC work? Some rational presumptions

  1. The sub atmospheric pressure around the wound produces a mechanical stress leading to an inflammatory response and angiogenesis which helps create granulation tissue. Such mechanical stress is known to produce angiogenesis in another technique called tissue expansion.
  2. The outflow of interstitial tissue both from the wound bed and the surrounding tissue helps reduce edema and allows greater blood flow and scavenging activity.
  3. The drainage of the exudate reduces harmful proteolytic enzymes a product of bacterial inflammatory activity and also reduces the bacterial load
  4. It has been postulated that the deformation of moribund cells is a stimulus for regeneration of new cells together with deposition of protein and cellular matrix.
  5. With the bacterial load decreasing this generation of new cells reduces wound size
  6. In those cases where dryness is a problem, newer models of the VAC machines also employ a separate channel for irrigation with an antibacterial fluid to maintain a moist environment in and around the wound 

Clinical applications

The VAC assisted treatment for wounds and ulcers is most frequently used with great success in the following conditions:

  1. Immediately for a highly contaminated wound after debridement in which the zones of viable and non-viable tissues are not apparent.
  2. The same kind of wound seen after an interval where contamination has led to infection the wound has become fulminant or indolent and needs to be prepared for skin cover.
  3. Dep and intermediate thickness burn wounds of a limited size which have not had the benefit of early skin cover and are being readied for skin cover.
  4. Sternal dehiscence or burst abdomens following surgery to improve the wounds prior to a final formal closure.
  5. Sizable pressure sores after an initial debridement or even in between successive debridements.
  6. Ulcers on the inferior extremity of venous diabetic or indeterminate etiology prior to their closure by skin cover.
  7. VAC has also been tried for entero-cutaneous fistulae.
  8. Necrotizing fasciitis after the lesion is reasonably controlled with parenteral antibiotics and after decompression of a compartment syndrome if it was present.
  9. The system is also extremely useful when skin grafting is performed particularly on uneven surfaces and where a tie-over dressing is difficult to maintain. The meshed graft is covered by the urethane foam and the suction helps oppose the graft to the recipient bed by taking away any exudate which might form a film preventing neo vascularization of the skin graft.

Under what circumstances the VAC system does not work or must be used with caution

  1. The VAC system does not help when the wound is covered with a thick eschar or in cases of osteomyelitis. In both conditions either a thorough debridement and/or removal of sequestra and shaving away of dead infected bone as well as the eschar must precede the application because the system is meant for improving wounds not to remove dead adherent tissue or to treat the underlying disease The VAC system also will not benefit in the treatment of fistulae surrounded by ulcers.
  2. The system must be used with great caution if the bed of the wound is occupied by an organ which is bare or major nerves or vessels are exposed in the wound and is best avoided.
  3. It is contraindicated in patients on anti-coagulant therapy for fear of bleeding  and for malignant lesions because negative pressure will stimulate cell growth and cause the spread of the lesion

Newer Modalities

VERAFLOW Technique:

VAC VERAFLOW is a newer modality of NPWT therapy marketed by KCI, in which the device has an option of irrigation of the wound by a topical solution like plain saline or topical antibiotic or antiseptic solution, with simultaneous intermittent negative suction and removal of the fluid. The “soak-time”, suction pressure and negative pressure can be modified as per requirements.

This therapy helps in cleaning the wound with topical solution, local delivery of topical antimicrobial or antiseptic solution, and maintaining a moist environment to improve the healing. The irrigation used in the VERAFLOW technique helps clean the wound and can also achieve local delivery of an antiseptic or an antibacterial solution in addition to keeping the wound moist.

Complications

There are no major complications associated with VAC therapy. Skin irritation may be noted in few patients. There may be some pain while changing VAC dressing. In some situations, the cost of the therapy also proves to be an issue that needs to be considered.

­­Clinical Examples

Following pictures contributed by Drs. Parag Sahasrabuddhe and Amey Bindu, Pune, Maharashtra, India

Following pictures contributed by Dr. Shailesh Ranade, Mumbai, Maharashtra, India

Following pictures contributed by Dr. Sitaram Prasad, Mumbai, Maharashtra, India

Avulsion Rt. Arm with Chest wall defect

Degloving Injury of Chest wall

Extravasation

Perineal Degloving

Sacral Pressure Sore

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