Letters to the Editor 391

saphenous flaps show these flaps have a delicate circulation, which is inadequate in most cases where the main pedicle vessels are skeletonised. Similar flaps in rabbits are equally delicate: if their distally based vein is divided (thereby also dividing the fine vessels around it) and then anastomosed to a local vein. most of the flaps necrose.g The plexus of fine veins is clearly important to ensure adequate venous drain- age.

The retrograde phlebography showed the main venae comitantes of the experimental flap pedicles were patent and had incompetent valves. It is fascinating that the valves of the venae comitantes distal to the pedicle pivot points were also incompetent. How? These veins had a high (56 cm of water) venous pressure, they had blood entering from the foot, and although the adjacent tibia1 nerve was intact, the vasomotor sympathetic nerves to the distal veins had been divided proximally when the flap was elevated. Dare I suggest that the combination of the three factors of the second hypothesis was in place?! Wee proposed the veins should be dissected distal to the pedicle pivot point to denervate them; the canine experiments show this is prob- ably not necessary.

In 1955, Rodbard reported that increasing outlet re- sistance can maintain or “paradoxically” increase fluid flow through collapsible rubber tubes for a given input press- ure.l.l” Del Pinal and Taylor’s experiments on isolated valved veins nicely add to this work.

The high blood flow, the raised venous pressure, the canine phlebograms and the clinical appearance of the veins in the pedicles of reverse radial forearm flaps all suggest the main venous return is down the venae comitantes in reverse flow flaps: the macrovenous cross connections and the fine venous plexus make this possible in most cases. Overall, de1 Pinal and Taylor’s findings support the framework of Wee’s refined hypothesis and the conclusions of Torii et al. Their results also explain the unreliability of experimental and clinical reverse flow free flaps, although in some modified cases these have been successful.”

A key factor is the smooth muscle, known to be in the walls and valve bases of veins,l” including deep veins.’ Sympathetic nerves, circulating hormones and local factors influence the smooth muscle tone.13 Del Pinal and Taylor are right; denervation is not the only cause of vein di!atation. Cold blood in deep venae comitantes makes them dilate (in contrast to the superficial veins which constrict),13 phlebot- omists daily confirm that superficial veins dilate (tempor- arily) in response to simple tapping,14 and others have shown that insertion of a needle alongside a vein, or local infiltration of lignocaine or saline can result in reversed venous flow.15 Nevertheless, smooth muscle dilatation by denervation still seems relevant to the original question of reverse flow in the pedicles of distally based radial forearm flaps.

In the 1990s we should now consider the vascular endothelium.‘“, Ii This has many regulatory functions, in- cluding the release of vasodilators such as endothelium- derived relaxing factor (EDRF) and vasoconstrictors such as endothelin-1 (see Figure); these may be the final pathway for some of the vascular changes in reverse flow flaps. Skin flap ischaemia raises plasma endothelin-1 levels.18 There is now an orally active endothelin receptor antagonist.lg Under- standing and controlling the vascular endothelium could open one of the doors to the next stage of vascular engineering for reconstructive surgery. Yours faithfully.

M. J. Timmons, MA, MChir, FRCS, Consultant Plastic Surgeon, St. Luke’s Hospital. Bradford BD5 ONA

References

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

II.

12.

13.

14.

15.

16.

17.

18.

19.

rimmons MJ. The vascular basis of the radial forearm flap. Plast Reconstr Surg 1986; 77: 80-92.

Lin S-D. Chung-Sheng L. Chiu C-C. Venous drainage in the reverse forearm flau. Plast Reconstr Surg 1984: 74: 508-12.

Emerson DJM. Sprigg A. Page RE. Some observations on the radial artery island flap. Br J Plast Surg 1985; 38 : 107-12.

Timmons MJ. William Harvey revisited: reverse flow through the valves of forearm veins. Lancet 1984: ii: 3945.

Wee JTK. Reconstruction of the lower leg and foot with the reverse-pedicled anterior tibia1 flap: preliminary report of a new fasciocutaneous Ran. Br J Plast Sure 1986; 39: 327-37.

Wee JTK. Venous flow in’the distally pedt%ed radial forearm flap: anatomical, physiological and surgical considerations. In: Gilbert A, Masquelet AC, Hentz VR. eds. Pedicle flaps of the upper limb. London: Martin Dunitz, 1992: 101-9.

Torii S. Namiki Y. Mori R. Reverse-flow island flaps: clinical report and venous drainage. Plast Reconstr Surg 1987: 79: 600-9.

Del Pinal F. Taylor GI. The deep venous system and reverse flow flaps. Br J Plast Surg 1993; 46: 652.--64.

Stewart DH. Puckett CL. Is reversed venous flow safe in free flap transfer? A dilemma with the radial forearm flap. Plast Reconstr Surg 1992; 89: 23742.

Rodbard S. Flow through collapsible tubes: augmented flow produced by resistance at the outlet. Circulation 1955: 11: 280-7.

Partecke B-D, Buck-Gramcko D. Free forearm flap for re- construction of soft tissue defects concurrent with improved peripheral circulation. J Reconstr Microsurg 1984: I : l-6.

Kampmeier OF, La Fleur Birch C. The origin and development of the venous valves, with particular reference to the saphenous district. Am J Anat 1927; 38: 45 I-99.

Vanhoutte PM, Janssens WJ. Local control of venous function. Microvasc Res 1978: 16: 196-214.

Franklin KJ. McLachlin AD. Dilatation of veins in response to tapping in man and other mammals. J Physiol (Land) 1936; 88 : 257-60.

Sassoon E. McGrouther DA. The superficial venous system: when is a valve not a valve? Winter Meeting of the British Association of Plastic Surgeons. London; December, 1992.

Shah AM. Vascular endothelium. Br J Hosp Med 1992; 48: 540-9.

Davies MC, Hagen P-O. The vascular endothelium: a new horizon. Ann Surg 1993; 218: 593-609.

Matsuzaki K. EfTect of skin flap ischemia on plasma endo- thelin-1 levels. Ann Plast Surg 1993 ; 3 I : 499-503.

Webb DJ, Haynes WC. Endothelins come of age. Lancet 1993; 342: 1439-40.

Letter received 15 February 1994

Flaps based on posterior tibia1 vessels

Sir, We have read with great interest the paper “The anatomic basis and clinical applications of flaps based on the posterior tibia1 vessels” by W. C. Wu et al.’

This publication has the merit of reviewing the use of flaps based on the posterior tibia1 vessels.

Since 1986, we have studied this vascular axis and published the distally based fasciocutaneous flap.”

This first report of a fasciocutaneous flap based on the distal direct fasciocutaneous branches has not been mentioned in the article by Wu et al. and we hope it may be kept in mind for future publications about this interesting subject.

Recently, as we have presented in a communication, we have used this fasciocutaneous flap in 38 clinical cases,” in seven of them to reconstruct the heel, in three to reconstruct the lateral malleolus and in two to reconstruct the medial malleolus.

292 British Journal of Plastic Surgery

Whenever possible we prefer to use this flap rather than the reversed pedicle posterior tibia1 flap4 as it is not necessary to sacrifice the posterior tibia1 artery.

When using reversed pedicle posterior tibia1 flaps, con- trary to the published cases in Wu et al., we prefer to include the most proximal septocutaneous perforator vessels to obtain a long vascular pedicle, which can reach to cover distal foot defect? and preserve the communicating branch between the posterior tibia1 and the peroneal vessels.

Although we have never seen it mentioned, it is important to preserve this constant branch to assure the arterial supply of the foot, as the plantar branches, following posterior tibia1 artery ligation, are revascularised via the peroneal artery. Yours faithfully,

Jo& Amarante, Professor and Chief of Plastic and Reconstructive Surgery, Jorge Reis, Consultant in Plastic and Reconstructive Surgery, Rua do Lidador 780, 4100 Porto, Portugal

References

I Wu WC, Chang YP, So YC, Yip SF, Lam YL. The anatomic basis and clinical applications of flaps based on the posterior tibia1 vessels. Br J Plast Surg 1993: 46: 47&9.

2. Amarante J, Costa M, Reis J,ISoares R. A new distally based fasciocutaneous flap of the leg. Br J Plast Surg 1986; 39: 33841.

3. Reis J, Amarante J, Martins A. Costa M, Soares R. Septocutaneous reverse-flow flaps: clinical applications in distal limb reconstruction. In: Hinderer UT, editor. Proc 10th Congr Int Conf Plast Ret Surg. Amsterdam: Elsevier Science Publishers, 1992: 25.

4. Hong G, Steffens K, Wang FB. Reconstruction of the lower leg and foot with the reverse pedicled posterior tibia1 fascio- cutaneous flap. Br J Plast Surg 1989; 42: 512-6.

The anatomic basis and clinical applications of flaps based on the posterior tibia1 vessels-reply

We appreciate very much the comments and remarks raised by Dr J. Amarante. We are certainly aware of the article by Dr Amarante and colleagues published in the British Journal of Plastic Surgery in 1986,’ however, it would be difficult to include all references in our paper. Indeed Dr L. K. Hung reminded me recently that the posterior tibia1 flap was first employed by Zhang and colleagues in the People’s Republic of China in 1983.2,3 The flap was initially named as the ‘medial leg flap’.

When using the reverse-flow posterior tibia1 fascio- cutaneous flap, the length of the vascular pedicle should be about 120 % the distance between the pivot point of the vascular pedicle to the proximal edge of the wound. This would avoid kinking of the vascular pedicle at the pivot point. The length of the vascular pedicle is important as it determines which zone the flap should come from and which direct cutaneous branch (DCB) is vital for flap survival.

Dr Amarante mentioned that they would like to include the most proximal direct cutaneous branch with the flap for resurfacing distal foot defects. We also share the same experience. I suppose those branches correspond to the DCBs in Zone III of the leg as described in our article. I would like to emphasise the importance of the surgical anatomy at this part of the leg as for the unwary they may

damage the DCBs. As one moves proximally from the ankle, the medial border of the soleus muscle gradually runs anteriorly from the back and finally adheres firmly to the periosteum of the tibia at Zone III. The posteromedial border of the tibia is in effect the merging point of the deep fascia of the leg (covering the soleus and gastrocnemius muscles), the deep transverse fascia of the leg, the anterior border of the flexor digitorum longus muscle and the tibia1 origin of the soleus muscle. DCBs in Zone III would pierce the fascia at this point and reach the skin. When these perforators are important and need to be included for flap survival, the deep fascia of the leg, the soleus origin and the deep transverse fascia of the leg must be dissected carefully away from the periosteum of the tibia and reflected posteriorly, the DCBs will follow the soleus muscle mass and be preserved. Since the deep transverse fascia of the leg at this level is thin, we would advise including the aponeurotic sheet on the deep surface of the soleus muscle with the flap to protect the DCBs during dissection.

Though it would be nice to preserve the communicating branch between the posterior tibia1 and peroneal arteries, we encountered no problem when this branch was ligated.

As had been discussed in the paper, the sacrifice of one main arterial supply to the foot has been a major worry in the use of this flap. We expect further studies on the use of tissues based on this vascular system would centre on 1) the long term follow-up results and the effect on the donor foot, 2) more elaborate use of the posterior tibia1 perforator- based flap, 3) the size of skin flap supplied by an individual perforator and 4) reliable and non-invasive means to locate the position of the direct cutaneous branches. Yours faithfully,

Dr Wing-Cheung Wu, FRCSEJ, FRACS, Department of Orthopaedics & Traumatology, Pamela Youde Nethersole Eastern Hospital, 3 Lok Man Road, Chai Wan, Hong Kong.

References

1. Amarante J. Costa H. Reis J. Soares R. A new distally based fasciocutaneous flap of the leg. Br J Plast Surg 1986; 39: 33840.

2. Hung LK, Chen SZ. Leung PC. Resurfacing difficult wounds: selective use of the posterior tibia1 flap. J Reconstr Micosurg 1990; 1: 13-9.

3. Zhang S. Li J, Song K, et al. Clinical applications of the free media1 leg flap. Chin Surg 1983; 21: 743-S.

Frontonasal flap procedure

Sir, I wish to inform you that the frontonasal flap described by S. de Fontaine et al.’ was described by Gillies as a ‘Bishop’s mitre’ based on a single or a double pedicle, for which credit has not been given to the originator of this very useful procedure which I have used on many occasions.

I cannot locate the exact reference to this Gillies pro- cedure, but find a short mention in Gillies and Millard’s The Principles and Art of Plastic Surgery.’ Yours faithfully,

N. H. Antia, FRCS, FACS(Hon), Ben Nevis. B. Desai Road, Bombay 400 036, India.