Intended for healthcare professionals

Endgames Picture Quiz

Management of soft tissue defects of the foot

BMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h1184 (Published 11 March 2015) Cite this as: BMJ 2015;350:h1184
  1. Alexander E J Trevatt, foundation year 2 doctor1,
  2. Richard O Igwe, foundation year 2 doctor2,
  3. Umraz Khan, consultant plastic surgeon3
  1. 1Royal Free London NHS Foundation Trust, Barnet Hospital, Barnet EN5 3DJ, UK,
  2. 2Homerton University Hospital NHS Foundation Trust, London, UK
  3. 3Frenchay Hospital, Frenchay Park Road, Bristol, UK
  1. Correspondence to: alextrevatt{at}gmail.com

A 57 year old man presented to his general practitioner with a pigmented lesion on the heel of his left foot. He had not previously sought medical advice about the lesion but had recently become worried that it was growing in size. He was fit and well with no medical history of note.

Excision biopsy confirmed that the lesion was a malignant melanoma and he was referred urgently for wide local excision according to melanoma guidelines. The histological margins were clear with no residual disease seen. Staging examinations were negative. The tumour was less than 1 mm thick and there was no evidence of locoregional or distant metastasis. The resultant excision defect measured 4×4 cm and was not amenable to primary closure.

Initially a split skin graft was used to reconstruct the wound. However, this was not durable enough and failed, so a plastic surgeon who specialised in lower limb reconstruction was consulted (fig 1).

Figure1

Fig 1 Reconstruction of a post-excisional wound on the patient’s left foot

Questions

  • 1. Why is wound reconstruction in the foot challenging?

  • 2. What type of reconstruction was used to close the post-excisional wound?

  • 3. What frameworks exist for soft tissue reconstruction and how can they be applied in daily practice?

  • 4. What types of defect can be adequately reconstructed with a split skin graft and when is a flap more appropriate?

Answers

1. Why is wound reconstruction in the foot challenging?

Short answer

The foot is subject to weight bearing stresses and requires sensate tissue reconstruction that can withstand the shearing forces present during ambulation. Reconstruction options are limited by the paucity of available adjacent soft tissue.

Long answer

The plantar skin of the foot is perfectly adapted to weight bearing. It is thicker than skin found elsewhere in the body and more heavily keratinised. Deep to the plantar skin is the strong plantar fascia, which provides extra support. Vertical compartmentalised fibrous septa extend from the plantar fascia into the dermis, providing resistance against the sheering forces that occur during ambulation.1

Soft tissue reconstruction in the foot must be durable and able to withstand the forces that occur during ambulation. It must also permit a normal range of movement and ideally allow patients to wear their usual footwear. Management of smaller more superficial wounds is less problematic, with simple wound closure techniques sufficing. However larger wounds, which are not manageable by primary sutures or adhesive strips, may require management in specialist centres.

A fundamental concept in plastic surgery is to replace like with like. This can be challenging in the foot because tissue taken from other parts of the body does not have the unique weight bearing properties seen in plantar skin. Sensation in the foot is also paramount to prevent damage secondary to mechanical trauma.2 Without sensation even the smallest stone in a patient’s shoe can cause serious injury if unknowingly gouged into the skin while walking. This adds another level of complexity to the management of wounds in the foot because any reconstruction ideally requires a viable nerve supply.

2. What type of reconstruction was used to close the post-excisional wound?

Short answer

A pedicled medial plantar flap based on the medial plantar artery, with inclusion of a branch of the medial plantar nerve and closure of the donor site by use of a split thickness skin graft (fig 2).

Figure2

Fig 2 Reconstruction of a post-excisional wound on the patient’s left foot. (A) A flap has been used to reconstruct the defect resulting from excision of the melanoma. (B) The flap donor site where non-weight bearing tissue was taken from to repair the original defect. The donor site has been reconstructed with a split skin graft. The picture was taken immediately after surgery

Long answer

The medial plantar flap is highly versatile and well suited for use in foot and ankle reconstruction. On standing, body weight is supported by the heels, the metatarsals, and the distal sole.2 The medial plantar region (over the arch of the foot) is generally non-weight bearing but retains its unique weight bearing characteristics. It can therefore be used to repair defects in this region with minimal functional consequences. Donor site morbidity must always be considered when planning complex tissue reconstruction. Although use of the medial plantar flap has some effect on intrinsic muscle function in the foot, this does not seem to affect ambulation.3 Because the area of the donor site provides a viable well vascularised wound bed it can be closed using a split skin graft. The medial plantar artery is derived from the posterior tibial artery and runs along the medial side of the foot, supplying nearby muscles and the plantar aspect of the big toe. The medial plantar nerve follows a similar course to that of the medial plantar artery and is derived from the tibial nerve. Motor branches of the medial plantar nerve supply the flexor digitorum brevis, abductor hallucis, and flexor hallucis brevis. It provides sensation to the medial sole and to the plantar regions of the big, second, third, and medial half of the forth toe. Distally it divides into the common plantar digital nerves.

A medial plantar flap can be raised based on the medial plantar artery. By incorporating a branch of the medial plantar nerve into the flap it is possible for sensation to return over time.4

3. What frameworks exist for soft tissue reconstruction and how can they be applied in daily practice?

Short answer

The soft tissue “reconstructive ladder” is a traditional metaphor designed to guide wound management, where interventions are attempted in order of complexity. More recent concepts such as the “reconstructive clockwork” emphasise adopting the most suitable reconstructive technique instead.

Long answer

Several techniques are available for reconstruction of soft tissue defects. Traditional management involved the use of the reconstructive ladder (fig 3A), where the simplest technique was attempted first. This was eventually superseded by the “surgical elevator” approach, where surgeons would move directly up to the reconstructive option of choice, bypassing less suitable techniques. However, in modern day surgical practice, where conventional methods alone may not be appropriate, surgeons tend towards a “reconstructive clockwork” approach (fig 3B).5 This allows for conventional reconstructive techniques to be used simultaneously with novel techniques from other fields to manage both the defect and any deformity or loss of function.

Figure3

Fig 3 Tissue reconstruction. (A) The reconstructive ladder. Treatments are attempted in order of complexity. (B) The reconstructive clockwork where conventional reconstructive techniques are used simultaneously to cover all aspects of wound management. Novel techniques from other fields such as robotics also play a role if appropriate.

The soft tissue reconstructive ladder remains a useful tool for junior doctors who are initially assessing a wound because it lists the different reconstructive options available and illustrates their varying complexity. It can provide a structured approach to deciding whether a wound can be managed locally or whether more specialist input is needed.

Once the appropriate referral has been made, the most suitable reconstructive option can then be decided upon using the reconstructive clockwork approach. This decision will be based on several factors, including the specific aspects of the defect and donor site, the surgeon’s ability, the facilities available, and the patient’s preferences.

In minor wounds where specialist input is not needed, healing by secondary intention or primary closure can be considered. Healing by secondary intention is a conservative form of management where no direct closure is attempted. Dressings are applied and the wound heals through the formation of granulation tissue. The advantage of this form of treatment is that surgical intervention is not needed and it leaves no donor defect; however, healing time is prolonged and regular dressings are required. It is generally used in smaller, superficial wounds where the wound edges cannot be easily apposed or in cases where primary closure may result in the formation of a cavity.

In primary closure, the tissue is re-approximated using sutures, staples, tape, or glue. It is most appropriate in clean wounds with wound edges that are easily apposed but should be avoided if infection is a possibility. Senior opinion should be sought if the wound is contaminated with irremovable foreign debris or there is dead space under the skin closure. When used appropriately, healing is quicker and cosmetic outcome is better for primary closure than for secondary closure.

4. What types of defect can be adequately reconstructed with a skin graft and when is a flap more appropriate?

Short answer

Skin grafts are nourished by the graft bed and thus require well vascularised wounds. Flaps carry their own blood supply and can be used in poorly vascularised wounds in which skin grafting would not be appropriate.

Long answer

A skin graft is a unit of skin taken from one part of the body and used to repair a defect elsewhere. Grafts include the entire epidermis and part of the dermis of variable thickness. Skin grafts that incorporate all the dermis are referred to as full thickness skin grafts. Where only a portion of the dermis is included, the term split skin graft is used. Skin grafts lack their own blood supply and rely entirely on the blood supply of the recipient bed. They are thus limited by the vascularity of the surgical bed they are resurfacing. Split skin grafts have fewer metabolic requirements than full thickness skin grafts and can therefore be used to resurface wounds with less ideal conditions. However, they are more fragile than full thickness skin grafts and can produce a worse aesthetic outcome.

Flaps, in contrast to skin grafts, are units of tissue that are harvested with their own blood supply and intrinsic circulation. They can therefore be used to repair defects where the vascularity of the surgical bed cannot be relied upon.

Split skin grafts are useful when a large surface area needs to be covered. Because split skin graft donor sites can heal spontaneously they can be re-harvested. This is opposed to flaps and full thickness skin grafts, which have a limited supply, particularly if multiple types of tissue are needed (for example, flaps bearing bone, periosteum, fasciocutaneous, and muscle components).

Patient outcome

The initial split thickness skin graft used in this patient probably failed because it was not durable enough to withstand the forces to which it was subjected in that region. A medial plantar flap was used to create a durable and sensate reconstruction of the post-excisional wound, in keeping with the principle of replacing like with like. This new skin graft is likely to last because it is not directly weight bearing and so will not be subject to the same forces as weight bearing areas. The patient recovered well from the procedure. He was soon able to ambulate and wear normal footwear. Sensation within the flap returned to near normal over the course of six months. The wide local excision performed to treat his melanoma was achieved with adequate disease clearance and he returned to normal life.

Notes

Cite this as: BMJ 2015;350:h1184

Footnotes

  • Competing interests: We have read and understood BMJ policy on declaration of interests and declare the following interests: none.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Patient consent obtained.

References

View Abstract

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