USE OF THE VENOUS FLAP FOR SALVAGE OF DIFFICULTRING AVULSION INJURIES

DARRELL BROOKS, M.D.,1* RUDOLF F. BUNTIC, M.D.,1 and CHRIS TAYLOR, M.D.2

Ring avulsion can lead to soft tissue compromise resulting in eventual digit failure or restriction of motion. The authors present use of thevenous flow through flap for simultaneous soft tissue and digital vessel reconstruction in severe ring avulsion injury. A retrospective reviewof ring avulsion injuries treated with transplantation of an arterialized (A-V-A) venous flap between 1999 and 2006 was conducted. Indica-tions included digits which were debrided and required soft tissue and digital artery reconstruction. Eight venous flaps were transplantedfor 3 Urbaniak class II and 5 Urbaniak class III ring avulsions. Average size of the venous flap was 6 cm2. All flaps and digits survivedwithout partial necrosis. The soft tissue envelope was supple in all cases. Total active motion (TAM) ranged from 160 to 2108. The arterial-ized venous flow-through flap is a reliable solution for the complex ring avulsion injury which requires simultaneous soft tissue and digitalvessel reconstruction. VVC 2008 Wiley-Liss, Inc. Microsurgery 28:397–402, 2008.

Ring avulsion presents several challenges for the recon-

structive surgeon. In its more severe pattern, ring avul-

sion creates a longitudinal traction and crush injury to the

soft tissue envelope and digital vessels. Occult vascular

lesions may occur proximal and distal to the area of

injury visualized with the operating microscope.1 A phys-

ical separation of vessels from the involved soft tissue

envelope may make this tissue prone to swelling and

ischemic change.2 Vessel repair restores axial blood flow

from the point of repair distally, yet flow to and from the

proximal degloved soft tissue envelope is random and

dependent on circulation through the subdermal plexus

(Fig. 1). As a result massive swelling can be seen with

ring avulsion injury (Fig. 2). Success, in this instance, is

dependent on an adequate strategy for both vascular and

skin/subcutaneous tissue reconstruction. At worst, the

digit replant fails. At best, the digit replant survives but

subsequent motion in compromised by an atrophic, re-

strictive soft tissue envelope (Fig. 3). Multiple solutions

have been proposed to replace the injured tissue including

shortening the bone to allow primary closure of healthier

tissues,3 flap advancement or transposition from the hand

or adjacent digits,4 or vein grafting followed by split

thickness skin grafting (STSG).5 The purpose of this

study is to describe the use of an arterialized venous flap

as an alternate approach for simultaneous soft tissue and

vessel reconstruction in ring avulsion injury.

METHODS

A retrospective review of ring avulsion injuries

treated with venous flaps at our facility between 1999

and 2006 was conducted. Indications for venous flap

transplantation were limited to ring avulsion injuries

requiring replacement of soft tissue and vessels.

Hospital records and radiographs were reviewed to

define the pattern of avulsion, classify the injury using

the Urbaniak system,6 and determine the size and config-

uration of each flap. Outcome analysis included flap sur-

vival, survival of the digit, as well as average total active

range of motion (TAM) as described by Kleinert.7

The degloved soft tissue envelope was everted allow-

ing exploration and debridement of the soft tissue enve-

lope, digital arteries, and veins (see Fig. 4). Venous flaps

were harvested from the distal volar surface of the ipsi-

lateral forearm based on a template of the soft tissue and

vessel defects. They were designed slightly larger than

the defect as small flow-through flaps, so that no flap

edge was more than 1.5 cms from a flowing vessel. All

flaps were reversed. Beginning at the time of anastomosis

and for 5 days postoperatively, intravenous dextran 40

was administered. When the distal target vessel could not

be further debrided and if there were still concerns about

vessel quality, heparin was added. Skin islands were

monitored by physical exam, fluorometry,8 and surface

Doppler confirming perfusion from day 1 through day 5

postoperatively.

RESULTS

Eight venous flaps were transplanted in eight patients

for ring avulsions between 1999 and 2006. All patients

were male and had their left ring fingers injured. Age

ranged from 27 to 38. There were 3 Urbaniak class II

and 5 Urbaniak class III injuries. Flaps were designed as

an ellipse centered over flow-through vessels. Flap size

averaged 6 cm2 (range 2 3 2 cm–2 3 4 cm). Two flaps

This work was presented, in part, at the American Society of ReconstructiveMicrosurgery, Palm Springs, CA. January 17–20, 2004.

1Microsurgeon Buncke Clinic, California Pacific Medical Center, San Fran-cisco, CA2Clinical Instructor Royal Jubilee Hospital, Victoria B.C.

*Correspondence to: Darrell Brooks, M.D., California Pacific Medical Center,45 Castro Street, San Francisco, CA 94114.E-mail: dbrooks@microsurgeon.org

Received 5 November 2007; Accepted 9 April 2008

Published online 11 July 2008 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/micr.20527

VVC 2008 Wiley-Liss, Inc.

were designed with parallel noncommunicating veins so

that one could be used for arterial and one for venous

reconstruction (Fig. 5). These flaps were reversed and the

vein segment used for venous outflow was evaluated to

ensure that there was no obstructing valve. All flaps were

arterialized in an artery-vein-artery (A-V-A) fashion (Fig.

6), thereby revascularizing the flap and re-establishing ar-

terial inflow to the digit. Donor sites were closed primar-

ily in all cases.

All digits and flaps survived without necrosis. Sec-

ondary surgeries included extensor tenolysis with MCP/

PIP joint capsulotomies (6), flexor tenolysis (6), DIP

fusion (4), soft tissue reduction (2). Average TAM was

1858 (range 160–2108) even though the DIP joint was

often injured and required fusion in four cases. Average

TAM increased 408 after tenolysis and joint capsulotomy.

The soft tissue envelope was supple in all cases.

CASE REPORT

A 24-year-old right hand dominant man while stack-

ing boxes on a shelf fell from his ladder catching the

ring on his left fourth digit on the shelf. The patient sus-

tained an Urbaniak Class II avulsion injury characterized

by crush avulsion of the soft tissue envelope, avulsion of

the distal extensor complex insertion, and disarticulation

of the DIP joint. Simultaneous revascularization and soft

tissue reconstruction with an arterialized venous flow-

through flap was performed acutely. The resultant soft

tissue was supple with areas of excess tissue rather than

atrophic or restrictive tissue. Even though the DIP joint

was subsequently fused, TAM at the MCP and PIP joints

was 1858 with excellent extension and flexion (Fig. 7).

DISCUSSION

A review9 of ring avulsion injury treated at our facil-

ity between 1977 and 2000 revealed a particularly chal-

lenging pattern. Despite the presence of adequate target

vessels, some Urbaniak type II and III injuries failed

from apparent soft tissue envelope complications. In all

cases, vein grafts to target vessels at or beyond the DIP

joint crease restored blood flow. Some digits treated with

vein grafts to healthy distal targets and primary closure

of the skin envelope developed venous congestion at 3 to

4 days postoperatively. Exploration revealed swelling,

epidermolysis, and venous obstruction. Swelling of the

soft tissue envelope with compression of the outflow

veins was thought to be the initiating event. Others

treated with aggressive soft tissue debridemente followed

by vein grafts and STSGs also became congested

between postoperative days 3 and 4. Exploration revealed

hematoma formation under the STSG with loss of venous

outflow. Failure was attributed to the use of heparin and

the potential for bleeding associated with the crush-

degloving mechanism of injury.

In our experience, class II and III degloving injuries,

which do not have physical separation or delamination of

the inflow and outflow vessels from their investing soft

tissues, are not associated with digit-threatening swelling

and do well with conservative measures combined with

minor debriement. Adani10 referred to these injuries when

he noted that the injury to the soft tissue envelope was

marginal and without need of surgical intervention. When

there is delamination of the soft tissue envelope, judg-

ment is required in managing the soft tissue injuries in

ring avulsion. Which tissue will survive and which needs

to be debrided is not always immediately clear. Tissue

that would survive under typical circumstances may fail

because of complicating factors, such as severe swelling

or hematoma. If there is physical separation of the digital

vessels from the soft tissue envelope, or if restoration of

axial flow to the digit effectively bypasses an intervening

segment of tissue, a strategy to protect or replace this

vulnerable segment of tissue must be employed.

Figure 1. Replanted ring avulsion with vein grafts to arterial and ve-

nous targets at the distal interphalangeal joint (DIPJ) crease. (X)

Point at which axial blood flow to the tip and non-axial retrograde

flow to the degloved skin envelope begins. (Y) Point at which ve-

nous drainage from the tip begins and point to which blood must

migrate retrograde to drain the degloved soft tissue envelope.

Shaded area illustrates the pattern of compromise of the dorsal

skin, which is thinner, more prone to injury and eventual compro-

mise. [Color figure can be viewed in the online issue, which is avail-

able at www.interscience.wiley.com.]

Figure 2. Near critical compromise of the soft tissue envelope is

noted three days after replantation of Urbaniak Class III avulsion

with disarticulation of the DIPJ. [Color figure can be viewed in the

online issue, which is available at www.interscience.wiley.com.]

398 Brooks et al.

Microsurgery DOI 10.1002/micr

A case report by Weeks11 recommended that a mid-

lateral incision be made, filleting the digit past the DIP

joint crease to allow complete decompression and protect

the digit which will become markedly edematous during

the immediate postoperative period. The wound was

closed immediately by a STSG. Behan4 described the Ve-

nous Island Conduit (VIC) flap, a composite venous flow

through flap pedicled from an adjacent digit to provide

Figure 3. (a) Urbaniak Class III ring avulsion amputation with fracture at the base of the middle phalanx. (b) Replantation with standard

split thickness skin and vein grafting. (c) Survival of replant with critical ischemia of the proximal soft tissue envelope. Dorsal view. (d) Vo-

lar view. (e) Resultant atrophic and restrictive soft tissue envelope 4 months after replantation. (f) Volar view. [Color figure can be viewed

in the online issue, which is available at www.interscience.wiley.com.]

Venous Flap for Salvage 399

Microsurgery DOI 10.1002/micr

soft tissue and venous reconstruction. Tsai12 transplanted

volar forearm venous flaps to the dorsum of the injured

digit with venous inflow (V-V-V pattern) to provide cov-

erage and bridge the venous gap. McDonald5 recom-

mended vein grafting to bridge the vascular defects and

split thickness skin grafts to provide coverage.

This study has shown that an arterialized venous flap

harvested from the volar forearm offers advantages over

other techniques in treating severe ring avulsion injuries

which require vessel and soft tissue reconstruction. In this

study, the venous flaps harvested from the forearm were

reliable, unlike those transplanted by Tsai which had a

100% failure rate. The failures in the Tsai study may have

been due to the inflow pattern rather than the forearm do-

nor site, as he postulated. Venous flaps with arterial inflow

such as those used in this study have been found to be

more reliable than venous flaps with venous inflow.13,14

The arterialized venous flaps can simultaneously restore

circulation to the digit and provide stable coverage, with-

out the associated risk to the function or esthetic of the

adjacent digit or hand itself. Except for flap design, this

procedure requires no more expertise than vein and

skin grafting and inflicts no more donor morbidity than

combined full thickness skin and vein grafts. The parallel

vein design was used to provide simultaneous artery and

vein reconstruction and not to improve flap size or perfu-

sion in these cases. Because the veins are inherently asso-

ciated with the venous flap, they are possibly less prone to

compromise should there be associated bleeding. This is

especially true of those cases in which parallel veins were

utilized for inflow and outflow. This design could be ad-

vantageous when questionable target vessels are employed

and the surgeon anticipates use of heparin or some other

form of anticoagulation.

Although skin grafts are an option, their disadvantages

in this setting include more than a higher hematoma risk.

Skin grafts require a well-vascularized bed, heal more

slowly and are less hardy than a vascularized flap, making

them more sensitive to infection and compromise. Skin

grafts do not augment local vascular inflow, but rather are

dependent on nutrients from the injured finger. The donor

tissue is used synergistically in an arterialized venous flap

rather than independently with the separate harvest of vein

and skin grafts. Exposure of tendon or bone in ring avul-

sion injury often precludes skin grafting as an option.

Relatively small venous flaps have been used effec-

tively in cases cited in this study. This indicates that an

essential step may be augmentation rather than complete

replacement of the traumatized tissue. Although the skin

envelope may be closed with minimal or no tension,

when the finger begins to swell, critical tension may de-

velop. Adding soft tissue can allow the digit to withstand

the sometimes massive swelling associated with a ring

avulsion injury, or may remove the cause of such swel-

ling. This also avoids procedures such as midlateral inci-

sions which not only might transect critical channels of

Figure 4. (a) Type III Urbaniak ring avulsion with DIP joint disarticu-

lation. (b) Eversion of the soft tissue envelope allows visualization

of vascular and nerve targets at DIP joint level. [Color figure can be

viewed in the online issue, which is available at www.interscience.

wiley.com.]

Figure 5. A venous flap designed to provide simultaneous replace-

ment of the dorsal soft tissue envelope, as well as arterial and venous

reconstruction. (Published with permission of www.microsurgeon.

org). [Color figure can be viewed in the online issue, which is avail-

able at www.interscience.wiley.com.]

Figure 6. The venous flap has been interposed between the two

ends of a digital artery, creating an artery-vein (flap)-artery con-

struct. [Color figure can be viewed in the online issue, which is

available at www.interscience.wiley.com.]

400 Brooks et al.

Microsurgery DOI 10.1002/micr

circulation in an already injured soft tissue envelope but

would also require skin grafting and result in a less desir-

able outcome.

Previous review of ring avulsion injuries treated at

our facility revealed that in the absence of joint or ten-

don injury at any particular level, resultant function is

primarily limited by the compliance of the soft tissue

envelope and adhesions to mobile structures. Cases

treated with skin grafts or allowed to heal partially by

secondary intension had a restrictive soft tissue enve-

Figure 7. (a) Type II Urbaniak ring avulsion injury with soft tissue envelope crush and DIP joint fracture dislocation. (b) Arterialized venous

flap transplanted from the forearm to reconstruct the radial digital artery and replace damaged soft tissue. (c) Resultant supple, mildly ex-

cessive rather than restrictive soft tissue envelope. (d) Resultant function, showing symmetric PIP joint hyperextension. (e) Near normal

flexion at the MCP and PIP joints. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Venous Flap for Salvage 401

Microsurgery DOI 10.1002/micr

lope which limited eventual range of motion. In this

study, all avulsions had tendon and bone injury distal to

the PIP joint. Venous flap transplantation produced a

supple soft tissue envelope, therefore tenolysis and cap-

sulotomy restored near normal range of motion in the

MCP and PIP joints. The improved quality of the soft

tissue envelope may also improve functional outcome,

although that cannot be conclusively determined from

this study.

Sharp amputations have a small zone of injury and

survival depends largely on the technique of vessel

repair. Ring avulsion, however, can have a much greater

zone of injury, and survival depends not only on micro-

vascular technique, but also on management of compro-

mised soft tissue and vessels. If there is a question of tis-

sue adequacy, we recommend resection and reconstruc-

tion with a venous flap. The venous flap provides a

solution for the dual problems of soft tissue envelope and

digital vessel injury in severe ring avulsions.

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