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Fingertip injuries
(i) Fingertip Injuries
D.
_I_.-
M. S. Kay
Introduction The human fingertip is the leading edge of tactile exploration, and has a disproportionately high representation on the sensory cortex. It is also the leading edge of that versatile tool, the human hand, and these two roles ensure that it is the most commonly injured part of our anatomy. The commonplace nature of fingertip injuries has failed to produce a consensus on how they might best be managed, and there are several reasons for this continuing uncertainty. Firstly, when treatment methods are compared, it is too often the case that like is not compared with like, either in the nature of the injury, the finger involved, the nature of the patient, or even in the nature of the surgeon. Secondly, the goals and priorities of treatment must be defined, and in this important organ the goals may vary from cosmesis, to rapid healing, to ensuring a pain-free stump, to the preservation of length at all cost. Finally, reports comparing treatments are often not randomised, and fail to address such consequences as nail deformity and cold intolerance. In this review we shall first address the nature of the injury and its inevitable sequelae, before addressing the possible treatment options, and their indications.
The injury Fingertip injuries are best divided into those with and without tissue loss. The varying contribution of crushing to the injury should be recognised. For our purposes a fingertip injury is one occurring distal to the insertion of the extensor and the profundus tendons, and Allen has classified the level of tip loss as shown in Figure 1, adding ‘c’ for crush injuries, or ‘a’ for clean amputations.* This review does not discuss injuries that are predominantly of the nail or extensor structures.
The twatment
Anatomy The fingertip is a beautifully adapted organ of sensation and prehension. The pulp is formed of glabrous skin bearing ridges which, with the aid of sweat excretion, provide tactile adhesion. The septated compartments of the pulp provide efficient shock absorption whilst resisting sheer, and allowing tremendous force transduction. The sensory innervation is David Martin Simon Kay FRCS, Department of Plastic Surgery, James’ University Hospital, Leeds LS.9 7TF. IJK
dense, whilst the vascular supply shunts through the pulp allowing high volume flow to nourish these most peripheral sensory organs. The pulp typically projects beyond the hyponychium (or pulp-nail-bed interface). The nail is adherent to the sterile matrix distally, which in turn is closely applied to underlying bone. The sterile matrix gives way to germinal matrix at the level of the lunula, and the nail fold extends proximal to overlie the distal aspect of the extensor insertion.
St
no tissue loss
Simple lacerations may be sutured, whilst burst lacerations are usually best left open, or loosely sutured with a 7/O absorbable suture (avoiding suture removal). Debridement should be conservative, although clear11 dead tissue must be excised. Nail bed lacerations should be carefully repaired under magnification using the same suture, and any mobilisation of the nail bed should be achieved in the subperiosteal plane. When the repair extends proximal to the lunula, the nail fold should be repaired in layers
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CURRENT
ORTHOPAEDICS-MINI-SYMPOSIUM:
Type
Allen’s
Classification
of Fingertip
Injuries
Fig. l-The Allen Classification of finger tip injuries. Adding a ‘c’ for crush injuries and an ‘a’ for clean amputations helps distinguish these two groups of injuries.
and in order to prevent the formation of synechiae it should be splinted using either the original nail, or one of the new commercial substitutes. Post-operatively the fingertip is dressed and elevated and a bupivacaine ring-block administered. We usually leave the wound undisturbed for fourteen days to minimise discomfort, although in some contaminated or untidy wounds earlier inspection may be wise. The treatment: tissue loss Conservative versus reconstructive treatment: the controversy. When tissue is lost from the digit tip a decision must be made as to whether it be replaced or not. In deciding on any operative course one must know the natural history of the condition treated, and this has been amply documented for fingertip injuries. Conservative treatment In children, there is little doubt that wound contracture and epithelialisation will provide satisfactory resolution of the wound in almost all cases. Das et al, in a prospective trial, compared sixty consecutive cases of tip injuries in children up to the age of twelve.* All levels of injury were included and the comparison was between local flap (this included trimming the bone back and primary closure), split skin graft and conservative treatment with tulle gras and tubigauze changed at weekly intervals. In the conservative group no anaesthetic was needed, there were no admissions to hospital and no days lost from school. Conservative treatment was ranked best for use, sensation, pinch, general appearance, and contour. The nail deformities that resulted were the least pronounced of the three groups. Two point discrimination was 3.5 mm compared to 4.5 mm for local flap and 7.5 mm for skin graft. Healing times were 5 weeks for conservative, 2.5 for skin graft and 3.5 for flaps. Other studies support conservative management as the management of choice in children.
THE HAND
Where the distal phalanx is degloved and stands proud of the wound, then it may be shortened to lie flush with the wound, and a dressing applied that need not be disturbed for 2 weeks. The majority of such wounds heal within 4 weeks, and differential contraction between the more mobile pulp and the fixed dorsal structures draws padded tissue over the bone end. Clearly there is a limit to the extent of loss that can be so treated, but it remains rare for children to need operative treatment of these injuries, In adults the indications have become muddied by two tenets of faith for some surgeons : namely that healing is not so exuberant as for children, and that return to work may be hastened by surgery. Both of these beliefs have now been challenged. Allen conducted an uncontrolled prospective assessment of conservative treatment of 60 consecutive tip injuries. l Exposed bone was nibbled back to allow soft tissue cover. Time lost from work was related to severity of injury using his own classification and for the most severely injured group averaged 28 days. Two point discrimination results were impressive, and tenderness and disability were moderate or severe in 14%. Cold sensitivity of a moderate or severe nature occurred in 16% and was mild in 30%. The majority of patients had a satisfactory pulp and there were no fissures or pigmentation in the group. Nail growth was abnormal in 49% and severely so in 18% and nail growth was particularly affected in injuries at the level of the lunule. Chow in a prospective study of 90 patients treated conservatively found sensory changes in 17x, tenderness in loA,joint stiffness in 2% and nail deformities in 27xe3 Nail deformities were particularly marked in injuries in the region of the lunula. Similarly good results have been reported by other authors49 5 and in most cases return to work times have been between 4 and 8 weeks, with no joint stiffness and sensory results comparable to or better than reconstructed cases. Most authors acknowledge problems with residual nail deformity. These results may seem surprising to many, but our conclusion is that the natural history of such injuries, particularly when transverse or nearly transverse, is relatively benign, so that surgical intervention must be reserved for those in whom conservative treatment will be inadequate, and must carry no significant additional morbidity. Many of the surgical methods advocated have been inadequately taught or have been used by surgeons without the required facilities or abilities in the belief that they are simple options and must be preferable to conservative treatment. Surgical treatment Surgery may be simply the shortening and closure of the stump, or the importation of new tissues to repair that which is lost, either by skin graft or by local or regional flap cover. Shortening and primary closure is a simple option that should be used with caution.
FINGERTIP
INJURIES
225
Sturman in his retrospective review of surgical intervention found 38% avoided use of the digit because of shortening.6 In his study of 45 similarly treated patients Bojsen-Mraller found 73% of patients complained of inconvenience due to shortening and that this was reflected in objective tests, being more prominent than for other treatment methods.s Both these studies identify significant levels of other symptoms including cold intolerance and tenderness and dysesthesia, although the latter was more pronounced in the conservatively managed group. Shortening proximal to the extensor tendon insertions is rarely needed, but where significant length is sacrificed it is wise to excise the germinal nail matrix. Time lost from work for these patients will still be in the region of 4 weeks, although this figure is often heavily influenced in western society by compensation related issues. Skin grafting
Reinnervation after nerve injury occurs at least in part to existing sensory end organs, and this has been cited to justify replacing missing skin with skin that contains higher densities of these organs. In fact studies that compare the results of skin grafting with other treatments do not identify convincing sensory benefits and many studies identify a problem prevalent following skin grafting, namely fissuring of the graft.7 We reserve grafting for those wounds in which skin is lost without volume loss, and these wounds are typically tangential slicing or abrasion injuries. Our preferred graft donor sites are the thenar crease, for full thickness grafts, or the border of the proximal phalanx for split skin grafts. The use of the volar forearm as a donor site for full thickness grafts to the fingertips (or to resurface a cross finger flap donor site) is contraindicated because of visible adverse scarring. The hypothenar donor site suffers the disadvantage of scar sensitivity and hypertrophy. Localflap cover
Resurfacing the digital tip by advancement of skin from within the same digit is far from simple, and is so frequently misleadingly described that the available techniques are described here in some detail. An important principle is that skin is advanced from a part of the digit that can spare it to resurface a part that is deficient, and when judging flap design the surgeon should always identify whence the spare skin is coming and whether it is truly spare. V-Y advancements The lateral advancement flaps (Kutler flaps) are well known and when Kutler tist proposed the technique it was a true innovation.8 This technique advances short wide lateral flaps on subcutaneous pedicles (Fig. 2A) and advocates shortening the bone if these flaps
Fig. 2-Three lateral advancement flaps are illustrated. (A) shows the traditional Kutler flap. This is based on a subcutaneous pedicle. (B) shows an extended V-Y flap which incorporates the neurovascular bundle by elevating it at the level of the periosteum. The inset cross sectional view shows how the volar edge of the flap is not divided completely, instead the flap is teased free to preserve all neurovascular elements. It provides a sensate flap to cover the tip. (C) shows the Step advancement flap which is very wide at its tip and is completely freed except for the neurovascular bundle. In this manner ample sensate tissue is provided for tip cover and the donor is closed in a manner that prevents a longitudinal volar scar. Note the proximal closure of the donor site as the flap is advanced.
do not come together without tension9 Such flap design based on an ill-defined and variable subcutaneous pedicle does not allow great advancement without the risk of flap necrosis, and many surgeons now believe that lateral V-Y advancement neurovascular island flaps are more satisfactory.‘O In these flaps the pedicle includes the axial neurovascular bundle of the digit, ensuring flap viability and immediate sensibility, and allowing extensive advancement with confidence. Shepard has highlighted important aspects of the technique in these cases . l OThe flaps may be long, and extend proximal to the distal interphalangeal crease provided that, when advanced, the stem of the Y will lie in the midaxial line (Fig. 2B). The dorsal incision is made down to the periosteum, and the flap raised off the phalanx in the surgical plane so freeing the septal attachments to bone. The volar incision is completed through dermis and then the subcutaneous tissues spread to identify and divide fibrous bands but preserve neurovascular structures as far as possible,
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ORTHOPAEDICS-MINI-SYMPOSIUM:
THE HAND
Fig. 3-The lateral V-Y flap is shown dissected enough to allow good advancement. Note the volar attachment of the flap. The results a few months later are also shown.
increasing sensibility and reducing microneuroma formation. It follows that magnification and toumiquet are mandatory for the adequate execution of the flap. Properly designed, the flap includes the digital neurovascular bundle and when completely raised may be advanced as much as 15 mm with ease (Fig. 3). We commonly advance the flaps from either side of the digit so that there is an apparent excess of tissue distally, before closure with 7/O absorbable sutures. The proximal limb is only closed loosely. A dressing is applied and left undisturbed for 14 days. The volar V-Y advancement flap similarly requires skilful surgery. Here the pulp septa are first freed from periosteum before the limbs of the V are gently spread to divide fibrous bands and preserve nerves and
vessels. Again these flaps may be taken as far proximal as the DIPJ flexion crease and advanced a considerable distance when fully freed (Fig. 4). Reports on the results of the lateral V-Y advancement flaps have to be interpreted carefully, since many of the earlier reports highlight deficiencies in Kutlers original technique, and identify problems such as tenderness, and sensitivity with altered sensation. These results are in our experience all too often the result of tight closure, lack of advancement or failure to close the donor defect satisfactorily so that it contracts and pulls the flap tight over the tip of the finger. Shepard has reported more encouraging results with his important modification of the lateral advancement
Fig. 4-Operative views of the volar V-Y. Note the freeing of the flap from the periosteum in the first photograph. The V of the flap is proximal to the DIPJ and good advancement is achieved.
FINGERTIP
flaps, and this has been more in keeping with our own findings. lo Typically the wounds are well healed at 2 weeks and protected return to work is feasible. The two point discrimination is less than 5 mm at 2 weeks, and a well padded and comfortable stump is achieved. Good projection of the pulp beyond the hyponychium adds to the aesthetic quality of the repair. To these two flap techniques many others have been added that redistribute tissue within the same finger. The report of Evans and Martin takes the neurovascular island principle one further logical step forward and allows skin to be advanced the length of the finger closing the donor defect primarily in the lateral aspect of the proximal phalanx where skin area is most redundant (Fig. 2C). l l The flap is dissected until it is attached only by the neurovascular bundle which should be left with a cuff of loose fatty and areolar tissue around it (Fig. 5). The authors emphasise the need for mobilisation to start at 5 days. Keim credits Moberg for the description of a flap that allows advancement of the whole volar skin on both neurovascular bundles, with or without grafting proximally. l2 We dislike this flap for finger injuries since occasional cases of dorsal sloughing have been reported, whilst in the thumb there is a risk of producing a flexion contracture in attempting to ‘make the thumb fit the flap’.
INJURIES
227
Regionalflap cover
There are a number of techniques for the importation of flap skin from sites outside the digit. In general the indications for these are extensive skin loss with preservation of skeleton and inability to adequately cover the wound from within the digit. The most commonly performed flap in this respect is the cross finger flap, which has been modified in a myriad of ways from its original form. The cross finger flap is raised from an adjacent digit and may be orientated transversely or oblique. It is dissected off the paratenon with great care taken not to disturb that structure and so prejudice skin graft survival on this donor site. This is especially important if the flap donor site crosses the proximal interphalangeal joint, as it may. If Clelands ligament over the dorsum of the neurovascular bundle is divided extra length for the flap may be achieved. The exact design, inset and subsequent division of the flap depend upon the individual circumstances but typically the flap is left pedicled for 2 weeks. The donor site is grafted, and a review of 35 such donor sites to assess the results of grafting showed that full thickness grafts gave consistently better aesthetic results than partial thickness grafts, although the latter gave many surprisingly good results.’ 3 Many studies have examined the results of cross
Fig. 5-h-1 the Step advancement flap note that the flap is retained only by the Neurovascular bundle and that the distal end of the flap is large enough to provide good bulk for cover of the tip. In the second photograph taken at the time of suture removal, the flap has good sensation with a short 2PD interval and the nonlinear volar scar avoids the risk of longitudinal contracture. The final result in the last photograph is cosmetically good.
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ORTHOPAEDICS-MINI-SYMPOSIUM:
finger flaps to finger tips, and like all such reports vary in their findings. Kleinert found that results were linked closely with age at surgery,14 whilst Porter reported good sensory return using these flaps.15 Sturman found sensory disturbance in 25%.6 Several authors have modified the flap by including a dorsal sensory nerve in the dissection, and repairing it to the digital nerve proper in an attempt to enhance sensory recovery. The thenarflap
Again, this flap has suffered from a bad press because of difficulties with its concept and execution. The flap is suitable for extended volar finger-tip loss and provides glabrous palmar skin with compartmentalised sub-cutaneous fat. It should not be confused with palmar flaps whose poor reputation is the result of the very flexed posture required of the recipient finger, and of the adverse donor scarring in the palm. Dellon has identified a number of important technical points in the use of this flap to minimise its morbidity.16 The flap is raised from the base of the thumb just proximal to the metacarpophalangeal joint and may be proximally or distally based. The donor defect is triangulated for direct closure, and the flap inset to the fingertip. We recommend division between 8 and 14 days in contrast to Dellon who cited 3 weeks. Earlier division has not so far resulted in the loss of a flap, and considerably minimises joint contracture at the proximal interphalangeal joint. When the flap is divided, it is often wise to leave tissue proud of the fingertip, and to perform nil, or minimal, closure of the tip. This wound will rapidly epithelialise and contract, and form a well rounded distal pulp, without any risk of strangulating its precarious new blood supply * Many of the reviews of this flap in the literature have concentrated on its use for small defects of the fingertip (more appropriately dealt with by other means) or have confused it with the palmar flaps mentioned above. When used for significant volar defects of fingertip, and harvested from the base of the thumb, this is a reliable and useful flap with little donor morbidity. Sensory ingrowth is slow but does occur and some authors have reported significant return of sensation comparable to other techniques. We have found sensory return rarely to offer better than a two point discrimination of 10 mm, but this is comparable with other methods when dealing with defects occupying most of the pulp. Microsurgery
In comparison to the large numbers of fingertip injuries seen, the opportunity to microsurgically reattach the amputated part is rare, since so often crushing or mutilation negate the effort. Nonetheless, this opportunity should be recognised when it occurs and the prospect discussed with the patient. When the
THE HAND
replantation is successful (and success rates are related to training, experience, the nature of the injury and patient factors such as smoking) it offers the best cosmetic and functional reconstruction, although the presence of a fracture in the distal phalanx may slow recovery somewhat. It has the disadvantage of cost and resource consumption, and so should be reserved for specialised cases in which the amputate is not badly traumatised, and the cosmetic or functional gain is worth the extra investment of resource.17 Free tissue transfer now offers the opportunity for reconstruction of the nail, pulp or entire fingertip using donor material from the foot, but is rarely indicated in the acute phase. The only exception to this is the acute reconstruction of avulsion of the pulp or integument of the thumb by a wrap around free flap from the great toe, in order to preserve spared skeleton. l*, l 9
Conclusion Fingertip injuries carry an inherent morbidity that appears to be unavoidable, including cold intolerance and sensitivity. Conservative treatment and its results show us the normally benign course of the simple transverse injury, especially in children, and for many will be hard to improve upon. Where bone stands proud of the soft tissues then simple trimming to render the injury transverse may be a required prelude to conservative treatment. Several surgical techniques have fallen into disrepute because of misunderstandings about their indications or execution. Skin grafting has little to recommend it in comparison with conservative treatment for transverse injuries, and should be reserved for simple skin loss without extensive pulp loss. Local flaps may be either true subcutaneous island flaps or neurovascular island flaps (Shepard lateral VY or Evans and Martin step advancement flap). We believe the latter type of flap to be most useful and now rarely find indication for the former. Neurovascular island flaps are reserved for patients in whom high quality pulp cover is required and length can be preserved without serious penalty. Properly indicated and executed these flaps do not prolong rehabilitation, and have very little morbidity, whilst providing immediate sensibility. Regional flaps are reserved for extensive soft tissue loss and allow preservation of length. They have the disadvantage of requiring at least two stages, and imply a donor site with its potential morbidity. We find the cross finger flap simple and reliable, but the donor defect is resented by many patients, especially females. For this reason we favour the thenar flap for the extensive volar skin and pulp loss in which dorsal structures are preserved. The donor morbidity is slight and attention to technique avoids recipient finger joint contractures. Extensive soft tissue loss carries its own penalties in terms of sensory return which few techniques can modify. Innervated flaps are rare and only used in our practice for pulp loss on the thumb,
FINGERTIP
when neurovascular free tissue transfer from the foot is the procedure of choice in the suitable patient. The plethora of conflicting reports on this subject is a result of the inherent morbidity of the injury, the large variety of available techniques and their applications, and the difficulty of assessing subjective results objectively. Surgeons treating these injuries should be aware of their natural history, and have a thorough understanding of the reconstructive methods available and of the exacting nature of their execution, without which satisfactory results will elude them. References 1. Allen M J. Conservative 2. 3. 4.
5. 6.
treatment of fingertip injuries in adults. Hand 1980; 12: 257 Das SK, Brown H G. Management of lost finger tips in children. The Hand 1978; 10 No 1: 1627 Chow S P, Ho E. Open treatment of fingertip injuries in adults. J Hand Surg 1982; 7: 47&476 Holm A, Zachariae L. Fingertip lesions: An evaluation of conservative treatment versus free skin graft. Acta Orthop Scandl974;45:382-392 Bojsen-Moller J, Pers M, Schmidt A. Finger-tip injuries: Late results. Acta Chir Stand 1961; 122: 177-183 Sturman M J, Duran R J. Late results of finger-tip injuries. J Bone Joint Surg 1963; 45(A) : 289-298
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229
7. Moynilan F J. Long term results of split skin grafting in finger tip injuries. Brit Med J 1961; 2: 802-805 8. Kutier W. A new method for fingertip amputations. JAMA 1947; 133: 29 9. Freiberg A, Manketelow R. The Kutler repair for fingertip amputations. Plast Reconstr Surg 1972; 50 No4: 371-374 10. Shepard G H. The use of lateral V-Y advancement flaps for fingertip reconstruction. J Hand Surg 1983; 8: 254 11. Evans D M, Martin D L. Step-advancement island flap for fingertip reconstruction. Brit J Plast Surg 1988; 41: 105-l 11 12. Keim H A, Grantham S A. Volar flap advancement for thumb and fingertip injuries. Clin Orthop 1969; 66: 109-l 12 13. Kay S P, Whitby D. St James’s University Hospital, Leeds. Unpublished data 14. Kleinert H B, McAlister C G, MacDonald C J, Kutz J E. A critical evaluation of cross finger flaps. J Trauma 1974; 14 No 9: 756764 15. Porter R W. Functional assessment of transplanted skin in volar defects of the digits. A comparison between free grafts and flaps. J Bone Joint Surg 1968; 50A: 955-963 16. Dellon A L. The proximal inset thenar flap for fingertip reconstruction. Plastic and Reconstructive Surgery 1982; 72 No 5 : 698-704 17. Urbaniak .I R, Roth J H, Nunley J A, Goldner R D, Koman L A. The results of replanatation after amputation of a single finger. J Bone Joint Surg 1985; 67A: 611-619 18. Morrison WA, O’Brien B McC, MacLeod AM. Thumb reconstruction with a free neurovascular wrap-around flap from the big toe. Hand Surg 1980; 5A: 575-583 19. Kay S. Microsurgical reconstruction of the thumb. Curr Orthop 1990; 4: 27-32
D.
_I_.-
M. S. Kay
Introduction The human fingertip is the leading edge of tactile exploration, and has a disproportionately high representation on the sensory cortex. It is also the leading edge of that versatile tool, the human hand, and these two roles ensure that it is the most commonly injured part of our anatomy. The commonplace nature of fingertip injuries has failed to produce a consensus on how they might best be managed, and there are several reasons for this continuing uncertainty. Firstly, when treatment methods are compared, it is too often the case that like is not compared with like, either in the nature of the injury, the finger involved, the nature of the patient, or even in the nature of the surgeon. Secondly, the goals and priorities of treatment must be defined, and in this important organ the goals may vary from cosmesis, to rapid healing, to ensuring a pain-free stump, to the preservation of length at all cost. Finally, reports comparing treatments are often not randomised, and fail to address such consequences as nail deformity and cold intolerance. In this review we shall first address the nature of the injury and its inevitable sequelae, before addressing the possible treatment options, and their indications.
The injury Fingertip injuries are best divided into those with and without tissue loss. The varying contribution of crushing to the injury should be recognised. For our purposes a fingertip injury is one occurring distal to the insertion of the extensor and the profundus tendons, and Allen has classified the level of tip loss as shown in Figure 1, adding ‘c’ for crush injuries, or ‘a’ for clean amputations.* This review does not discuss injuries that are predominantly of the nail or extensor structures.
The twatment
Anatomy The fingertip is a beautifully adapted organ of sensation and prehension. The pulp is formed of glabrous skin bearing ridges which, with the aid of sweat excretion, provide tactile adhesion. The septated compartments of the pulp provide efficient shock absorption whilst resisting sheer, and allowing tremendous force transduction. The sensory innervation is David Martin Simon Kay FRCS, Department of Plastic Surgery, James’ University Hospital, Leeds LS.9 7TF. IJK
dense, whilst the vascular supply shunts through the pulp allowing high volume flow to nourish these most peripheral sensory organs. The pulp typically projects beyond the hyponychium (or pulp-nail-bed interface). The nail is adherent to the sterile matrix distally, which in turn is closely applied to underlying bone. The sterile matrix gives way to germinal matrix at the level of the lunula, and the nail fold extends proximal to overlie the distal aspect of the extensor insertion.
St
no tissue loss
Simple lacerations may be sutured, whilst burst lacerations are usually best left open, or loosely sutured with a 7/O absorbable suture (avoiding suture removal). Debridement should be conservative, although clear11 dead tissue must be excised. Nail bed lacerations should be carefully repaired under magnification using the same suture, and any mobilisation of the nail bed should be achieved in the subperiosteal plane. When the repair extends proximal to the lunula, the nail fold should be repaired in layers
224
CURRENT
ORTHOPAEDICS-MINI-SYMPOSIUM:
Type
Allen’s
Classification
of Fingertip
Injuries
Fig. l-The Allen Classification of finger tip injuries. Adding a ‘c’ for crush injuries and an ‘a’ for clean amputations helps distinguish these two groups of injuries.
and in order to prevent the formation of synechiae it should be splinted using either the original nail, or one of the new commercial substitutes. Post-operatively the fingertip is dressed and elevated and a bupivacaine ring-block administered. We usually leave the wound undisturbed for fourteen days to minimise discomfort, although in some contaminated or untidy wounds earlier inspection may be wise. The treatment: tissue loss Conservative versus reconstructive treatment: the controversy. When tissue is lost from the digit tip a decision must be made as to whether it be replaced or not. In deciding on any operative course one must know the natural history of the condition treated, and this has been amply documented for fingertip injuries. Conservative treatment In children, there is little doubt that wound contracture and epithelialisation will provide satisfactory resolution of the wound in almost all cases. Das et al, in a prospective trial, compared sixty consecutive cases of tip injuries in children up to the age of twelve.* All levels of injury were included and the comparison was between local flap (this included trimming the bone back and primary closure), split skin graft and conservative treatment with tulle gras and tubigauze changed at weekly intervals. In the conservative group no anaesthetic was needed, there were no admissions to hospital and no days lost from school. Conservative treatment was ranked best for use, sensation, pinch, general appearance, and contour. The nail deformities that resulted were the least pronounced of the three groups. Two point discrimination was 3.5 mm compared to 4.5 mm for local flap and 7.5 mm for skin graft. Healing times were 5 weeks for conservative, 2.5 for skin graft and 3.5 for flaps. Other studies support conservative management as the management of choice in children.
THE HAND
Where the distal phalanx is degloved and stands proud of the wound, then it may be shortened to lie flush with the wound, and a dressing applied that need not be disturbed for 2 weeks. The majority of such wounds heal within 4 weeks, and differential contraction between the more mobile pulp and the fixed dorsal structures draws padded tissue over the bone end. Clearly there is a limit to the extent of loss that can be so treated, but it remains rare for children to need operative treatment of these injuries, In adults the indications have become muddied by two tenets of faith for some surgeons : namely that healing is not so exuberant as for children, and that return to work may be hastened by surgery. Both of these beliefs have now been challenged. Allen conducted an uncontrolled prospective assessment of conservative treatment of 60 consecutive tip injuries. l Exposed bone was nibbled back to allow soft tissue cover. Time lost from work was related to severity of injury using his own classification and for the most severely injured group averaged 28 days. Two point discrimination results were impressive, and tenderness and disability were moderate or severe in 14%. Cold sensitivity of a moderate or severe nature occurred in 16% and was mild in 30%. The majority of patients had a satisfactory pulp and there were no fissures or pigmentation in the group. Nail growth was abnormal in 49% and severely so in 18% and nail growth was particularly affected in injuries at the level of the lunule. Chow in a prospective study of 90 patients treated conservatively found sensory changes in 17x, tenderness in loA,joint stiffness in 2% and nail deformities in 27xe3 Nail deformities were particularly marked in injuries in the region of the lunula. Similarly good results have been reported by other authors49 5 and in most cases return to work times have been between 4 and 8 weeks, with no joint stiffness and sensory results comparable to or better than reconstructed cases. Most authors acknowledge problems with residual nail deformity. These results may seem surprising to many, but our conclusion is that the natural history of such injuries, particularly when transverse or nearly transverse, is relatively benign, so that surgical intervention must be reserved for those in whom conservative treatment will be inadequate, and must carry no significant additional morbidity. Many of the surgical methods advocated have been inadequately taught or have been used by surgeons without the required facilities or abilities in the belief that they are simple options and must be preferable to conservative treatment. Surgical treatment Surgery may be simply the shortening and closure of the stump, or the importation of new tissues to repair that which is lost, either by skin graft or by local or regional flap cover. Shortening and primary closure is a simple option that should be used with caution.
FINGERTIP
INJURIES
225
Sturman in his retrospective review of surgical intervention found 38% avoided use of the digit because of shortening.6 In his study of 45 similarly treated patients Bojsen-Mraller found 73% of patients complained of inconvenience due to shortening and that this was reflected in objective tests, being more prominent than for other treatment methods.s Both these studies identify significant levels of other symptoms including cold intolerance and tenderness and dysesthesia, although the latter was more pronounced in the conservatively managed group. Shortening proximal to the extensor tendon insertions is rarely needed, but where significant length is sacrificed it is wise to excise the germinal nail matrix. Time lost from work for these patients will still be in the region of 4 weeks, although this figure is often heavily influenced in western society by compensation related issues. Skin grafting
Reinnervation after nerve injury occurs at least in part to existing sensory end organs, and this has been cited to justify replacing missing skin with skin that contains higher densities of these organs. In fact studies that compare the results of skin grafting with other treatments do not identify convincing sensory benefits and many studies identify a problem prevalent following skin grafting, namely fissuring of the graft.7 We reserve grafting for those wounds in which skin is lost without volume loss, and these wounds are typically tangential slicing or abrasion injuries. Our preferred graft donor sites are the thenar crease, for full thickness grafts, or the border of the proximal phalanx for split skin grafts. The use of the volar forearm as a donor site for full thickness grafts to the fingertips (or to resurface a cross finger flap donor site) is contraindicated because of visible adverse scarring. The hypothenar donor site suffers the disadvantage of scar sensitivity and hypertrophy. Localflap cover
Resurfacing the digital tip by advancement of skin from within the same digit is far from simple, and is so frequently misleadingly described that the available techniques are described here in some detail. An important principle is that skin is advanced from a part of the digit that can spare it to resurface a part that is deficient, and when judging flap design the surgeon should always identify whence the spare skin is coming and whether it is truly spare. V-Y advancements The lateral advancement flaps (Kutler flaps) are well known and when Kutler tist proposed the technique it was a true innovation.8 This technique advances short wide lateral flaps on subcutaneous pedicles (Fig. 2A) and advocates shortening the bone if these flaps
Fig. 2-Three lateral advancement flaps are illustrated. (A) shows the traditional Kutler flap. This is based on a subcutaneous pedicle. (B) shows an extended V-Y flap which incorporates the neurovascular bundle by elevating it at the level of the periosteum. The inset cross sectional view shows how the volar edge of the flap is not divided completely, instead the flap is teased free to preserve all neurovascular elements. It provides a sensate flap to cover the tip. (C) shows the Step advancement flap which is very wide at its tip and is completely freed except for the neurovascular bundle. In this manner ample sensate tissue is provided for tip cover and the donor is closed in a manner that prevents a longitudinal volar scar. Note the proximal closure of the donor site as the flap is advanced.
do not come together without tension9 Such flap design based on an ill-defined and variable subcutaneous pedicle does not allow great advancement without the risk of flap necrosis, and many surgeons now believe that lateral V-Y advancement neurovascular island flaps are more satisfactory.‘O In these flaps the pedicle includes the axial neurovascular bundle of the digit, ensuring flap viability and immediate sensibility, and allowing extensive advancement with confidence. Shepard has highlighted important aspects of the technique in these cases . l OThe flaps may be long, and extend proximal to the distal interphalangeal crease provided that, when advanced, the stem of the Y will lie in the midaxial line (Fig. 2B). The dorsal incision is made down to the periosteum, and the flap raised off the phalanx in the surgical plane so freeing the septal attachments to bone. The volar incision is completed through dermis and then the subcutaneous tissues spread to identify and divide fibrous bands but preserve neurovascular structures as far as possible,
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Fig. 3-The lateral V-Y flap is shown dissected enough to allow good advancement. Note the volar attachment of the flap. The results a few months later are also shown.
increasing sensibility and reducing microneuroma formation. It follows that magnification and toumiquet are mandatory for the adequate execution of the flap. Properly designed, the flap includes the digital neurovascular bundle and when completely raised may be advanced as much as 15 mm with ease (Fig. 3). We commonly advance the flaps from either side of the digit so that there is an apparent excess of tissue distally, before closure with 7/O absorbable sutures. The proximal limb is only closed loosely. A dressing is applied and left undisturbed for 14 days. The volar V-Y advancement flap similarly requires skilful surgery. Here the pulp septa are first freed from periosteum before the limbs of the V are gently spread to divide fibrous bands and preserve nerves and
vessels. Again these flaps may be taken as far proximal as the DIPJ flexion crease and advanced a considerable distance when fully freed (Fig. 4). Reports on the results of the lateral V-Y advancement flaps have to be interpreted carefully, since many of the earlier reports highlight deficiencies in Kutlers original technique, and identify problems such as tenderness, and sensitivity with altered sensation. These results are in our experience all too often the result of tight closure, lack of advancement or failure to close the donor defect satisfactorily so that it contracts and pulls the flap tight over the tip of the finger. Shepard has reported more encouraging results with his important modification of the lateral advancement
Fig. 4-Operative views of the volar V-Y. Note the freeing of the flap from the periosteum in the first photograph. The V of the flap is proximal to the DIPJ and good advancement is achieved.
FINGERTIP
flaps, and this has been more in keeping with our own findings. lo Typically the wounds are well healed at 2 weeks and protected return to work is feasible. The two point discrimination is less than 5 mm at 2 weeks, and a well padded and comfortable stump is achieved. Good projection of the pulp beyond the hyponychium adds to the aesthetic quality of the repair. To these two flap techniques many others have been added that redistribute tissue within the same finger. The report of Evans and Martin takes the neurovascular island principle one further logical step forward and allows skin to be advanced the length of the finger closing the donor defect primarily in the lateral aspect of the proximal phalanx where skin area is most redundant (Fig. 2C). l l The flap is dissected until it is attached only by the neurovascular bundle which should be left with a cuff of loose fatty and areolar tissue around it (Fig. 5). The authors emphasise the need for mobilisation to start at 5 days. Keim credits Moberg for the description of a flap that allows advancement of the whole volar skin on both neurovascular bundles, with or without grafting proximally. l2 We dislike this flap for finger injuries since occasional cases of dorsal sloughing have been reported, whilst in the thumb there is a risk of producing a flexion contracture in attempting to ‘make the thumb fit the flap’.
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Regionalflap cover
There are a number of techniques for the importation of flap skin from sites outside the digit. In general the indications for these are extensive skin loss with preservation of skeleton and inability to adequately cover the wound from within the digit. The most commonly performed flap in this respect is the cross finger flap, which has been modified in a myriad of ways from its original form. The cross finger flap is raised from an adjacent digit and may be orientated transversely or oblique. It is dissected off the paratenon with great care taken not to disturb that structure and so prejudice skin graft survival on this donor site. This is especially important if the flap donor site crosses the proximal interphalangeal joint, as it may. If Clelands ligament over the dorsum of the neurovascular bundle is divided extra length for the flap may be achieved. The exact design, inset and subsequent division of the flap depend upon the individual circumstances but typically the flap is left pedicled for 2 weeks. The donor site is grafted, and a review of 35 such donor sites to assess the results of grafting showed that full thickness grafts gave consistently better aesthetic results than partial thickness grafts, although the latter gave many surprisingly good results.’ 3 Many studies have examined the results of cross
Fig. 5-h-1 the Step advancement flap note that the flap is retained only by the Neurovascular bundle and that the distal end of the flap is large enough to provide good bulk for cover of the tip. In the second photograph taken at the time of suture removal, the flap has good sensation with a short 2PD interval and the nonlinear volar scar avoids the risk of longitudinal contracture. The final result in the last photograph is cosmetically good.
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finger flaps to finger tips, and like all such reports vary in their findings. Kleinert found that results were linked closely with age at surgery,14 whilst Porter reported good sensory return using these flaps.15 Sturman found sensory disturbance in 25%.6 Several authors have modified the flap by including a dorsal sensory nerve in the dissection, and repairing it to the digital nerve proper in an attempt to enhance sensory recovery. The thenarflap
Again, this flap has suffered from a bad press because of difficulties with its concept and execution. The flap is suitable for extended volar finger-tip loss and provides glabrous palmar skin with compartmentalised sub-cutaneous fat. It should not be confused with palmar flaps whose poor reputation is the result of the very flexed posture required of the recipient finger, and of the adverse donor scarring in the palm. Dellon has identified a number of important technical points in the use of this flap to minimise its morbidity.16 The flap is raised from the base of the thumb just proximal to the metacarpophalangeal joint and may be proximally or distally based. The donor defect is triangulated for direct closure, and the flap inset to the fingertip. We recommend division between 8 and 14 days in contrast to Dellon who cited 3 weeks. Earlier division has not so far resulted in the loss of a flap, and considerably minimises joint contracture at the proximal interphalangeal joint. When the flap is divided, it is often wise to leave tissue proud of the fingertip, and to perform nil, or minimal, closure of the tip. This wound will rapidly epithelialise and contract, and form a well rounded distal pulp, without any risk of strangulating its precarious new blood supply * Many of the reviews of this flap in the literature have concentrated on its use for small defects of the fingertip (more appropriately dealt with by other means) or have confused it with the palmar flaps mentioned above. When used for significant volar defects of fingertip, and harvested from the base of the thumb, this is a reliable and useful flap with little donor morbidity. Sensory ingrowth is slow but does occur and some authors have reported significant return of sensation comparable to other techniques. We have found sensory return rarely to offer better than a two point discrimination of 10 mm, but this is comparable with other methods when dealing with defects occupying most of the pulp. Microsurgery
In comparison to the large numbers of fingertip injuries seen, the opportunity to microsurgically reattach the amputated part is rare, since so often crushing or mutilation negate the effort. Nonetheless, this opportunity should be recognised when it occurs and the prospect discussed with the patient. When the
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replantation is successful (and success rates are related to training, experience, the nature of the injury and patient factors such as smoking) it offers the best cosmetic and functional reconstruction, although the presence of a fracture in the distal phalanx may slow recovery somewhat. It has the disadvantage of cost and resource consumption, and so should be reserved for specialised cases in which the amputate is not badly traumatised, and the cosmetic or functional gain is worth the extra investment of resource.17 Free tissue transfer now offers the opportunity for reconstruction of the nail, pulp or entire fingertip using donor material from the foot, but is rarely indicated in the acute phase. The only exception to this is the acute reconstruction of avulsion of the pulp or integument of the thumb by a wrap around free flap from the great toe, in order to preserve spared skeleton. l*, l 9
Conclusion Fingertip injuries carry an inherent morbidity that appears to be unavoidable, including cold intolerance and sensitivity. Conservative treatment and its results show us the normally benign course of the simple transverse injury, especially in children, and for many will be hard to improve upon. Where bone stands proud of the soft tissues then simple trimming to render the injury transverse may be a required prelude to conservative treatment. Several surgical techniques have fallen into disrepute because of misunderstandings about their indications or execution. Skin grafting has little to recommend it in comparison with conservative treatment for transverse injuries, and should be reserved for simple skin loss without extensive pulp loss. Local flaps may be either true subcutaneous island flaps or neurovascular island flaps (Shepard lateral VY or Evans and Martin step advancement flap). We believe the latter type of flap to be most useful and now rarely find indication for the former. Neurovascular island flaps are reserved for patients in whom high quality pulp cover is required and length can be preserved without serious penalty. Properly indicated and executed these flaps do not prolong rehabilitation, and have very little morbidity, whilst providing immediate sensibility. Regional flaps are reserved for extensive soft tissue loss and allow preservation of length. They have the disadvantage of requiring at least two stages, and imply a donor site with its potential morbidity. We find the cross finger flap simple and reliable, but the donor defect is resented by many patients, especially females. For this reason we favour the thenar flap for the extensive volar skin and pulp loss in which dorsal structures are preserved. The donor morbidity is slight and attention to technique avoids recipient finger joint contractures. Extensive soft tissue loss carries its own penalties in terms of sensory return which few techniques can modify. Innervated flaps are rare and only used in our practice for pulp loss on the thumb,
FINGERTIP
when neurovascular free tissue transfer from the foot is the procedure of choice in the suitable patient. The plethora of conflicting reports on this subject is a result of the inherent morbidity of the injury, the large variety of available techniques and their applications, and the difficulty of assessing subjective results objectively. Surgeons treating these injuries should be aware of their natural history, and have a thorough understanding of the reconstructive methods available and of the exacting nature of their execution, without which satisfactory results will elude them. References 1. Allen M J. Conservative 2. 3. 4.
5. 6.
treatment of fingertip injuries in adults. Hand 1980; 12: 257 Das SK, Brown H G. Management of lost finger tips in children. The Hand 1978; 10 No 1: 1627 Chow S P, Ho E. Open treatment of fingertip injuries in adults. J Hand Surg 1982; 7: 47&476 Holm A, Zachariae L. Fingertip lesions: An evaluation of conservative treatment versus free skin graft. Acta Orthop Scandl974;45:382-392 Bojsen-Moller J, Pers M, Schmidt A. Finger-tip injuries: Late results. Acta Chir Stand 1961; 122: 177-183 Sturman M J, Duran R J. Late results of finger-tip injuries. J Bone Joint Surg 1963; 45(A) : 289-298
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7. Moynilan F J. Long term results of split skin grafting in finger tip injuries. Brit Med J 1961; 2: 802-805 8. Kutier W. A new method for fingertip amputations. JAMA 1947; 133: 29 9. Freiberg A, Manketelow R. The Kutler repair for fingertip amputations. Plast Reconstr Surg 1972; 50 No4: 371-374 10. Shepard G H. The use of lateral V-Y advancement flaps for fingertip reconstruction. J Hand Surg 1983; 8: 254 11. Evans D M, Martin D L. Step-advancement island flap for fingertip reconstruction. Brit J Plast Surg 1988; 41: 105-l 11 12. Keim H A, Grantham S A. Volar flap advancement for thumb and fingertip injuries. Clin Orthop 1969; 66: 109-l 12 13. Kay S P, Whitby D. St James’s University Hospital, Leeds. Unpublished data 14. Kleinert H B, McAlister C G, MacDonald C J, Kutz J E. A critical evaluation of cross finger flaps. J Trauma 1974; 14 No 9: 756764 15. Porter R W. Functional assessment of transplanted skin in volar defects of the digits. A comparison between free grafts and flaps. J Bone Joint Surg 1968; 50A: 955-963 16. Dellon A L. The proximal inset thenar flap for fingertip reconstruction. Plastic and Reconstructive Surgery 1982; 72 No 5 : 698-704 17. Urbaniak .I R, Roth J H, Nunley J A, Goldner R D, Koman L A. The results of replanatation after amputation of a single finger. J Bone Joint Surg 1985; 67A: 611-619 18. Morrison WA, O’Brien B McC, MacLeod AM. Thumb reconstruction with a free neurovascular wrap-around flap from the big toe. Hand Surg 1980; 5A: 575-583 19. Kay S. Microsurgical reconstruction of the thumb. Curr Orthop 1990; 4: 27-32