Distal replantation, nail bed, and nail problems in musicians

Precise tactile localization on the human fingernail

Fingernails are specialized features of the primate hand, which are believed to contribute to manual dexterity. The sensorimotor functions of fingernails, however, remain poorly understood. This study investigates the ability of humans to precisely localize touches applied to the fingernail plate. Nine different locations on the fingernail were touched and participants judged the location by clicking a mouse cursor on a photograph of their finger. Performance in this condition was compared with stimuli applied to the skin of the fingertip. The results showed that participants are able to localize touch on the fingernails at substantially higher than chance levels. Moreover, the precision of this ability is not appreciably lower than that of the fingertips. These results show that the fingernail is a highly sensitive sensory organ, which is capable of providing rich spatial information about tactile stimuli.

Microsurgical reconstruction of the nail

Very often, post-traumatic defects involve multiple tissues. Microsurgical techniques can reconstruct them with tissues taken from a toe: from the nail complex alone to compound osteo-onychocutaneous flaps. Several techniques have been reported since the 1980s. This paper describes techniques and indications for microsurgical nail reconstruction. Technique differs according to the deficit, and first and foremost whether only the nail complex is involved or whether other components of the fingertip important for the normal growth of the nail, such as the phalanx bone or the finger pad, are also missing (toenail flaps and the custom-made osteo-onychocutaneous flaps). For most patients the absence of a fingernail is an esthetic rather than functional concern, and the outcomes of microsurgical reconstruction are far from ideal in this regard. We prefer to reserve reconstruction for symptomatic patients with functional impairment.

Fingernail injury

Fingertip injuries are the most common injury to the hand. The nail represents a unique structure in the human body providing in fine pinch, stability and protection. Management of fingertip injuries can often be a challenging experience, especially in presence of complex lesion that include soft tissue loss and distal phalanx injury. In this review we present a variety of options in caring for these injuries to help achieve and avoid the sequels. The goal of treatment is restoration of a painless, functional digit with protective sensation.

Fingertip Injuries in Athletes, Musicians, and Other Special Cases

Management of fingertip injuries in athletes is optimized by consideration of the sport, the playing position, the timing within the season, the level of competition, and the patient's goals. Mallet and jersey fingers are common injuries in athletes and may be treated in several different ways, based on the nature of the injury and the timing of presentation, as well as the athlete's demands. Management of fingertip injuries in musicians is optimized by consideration of how the musician handles his or her instrument and the specific requirements of the injured digit in the context of musical performance.

The 'Te' Technique for Restoring Fingertip Stability Post Traumatic Acro-Osteolysis - A Report and Review of Management Options

BACKGROUND

Fractures of the distal phalanx can result in bony non-union, resulting in acro-osteolysis and subsequent fingertip instability due to soft tissue dissociation from bone. Conventional methods of treating this involve osseous fixation, but do not address the laxity and lack of soft tissue stability with bone. Current techniques also do not address the management of such conditions if bony fragments are too small to reduce. We present a novel method that addresses both soft tissue and bony deformity in this condition.

METHODS

A review of current techniques in the literature is provided as well as an in depth description of our technique using a representative case.

RESULTS

Follow-up results and photographs are presented in this article. Functional assessment is also provided in the article as part of the follow-up.

CONCLUSIONS

This technique is applicable for cases where severe resorption of distal phalanx has occurred, leaving little or no purchase for bony fixation. Hence, the technique can not only be applied post traumatic acro-osteolysis, but also other conditions where secondary soft tissue lengthening occurs and fingertip instability is formed as a result.

Primary functional and aesthetic restoration of the fingernail in distal fingertip amputations with the eponychial flap

Fingertip injuries often result in fingernail defects. Reconstruction of this structure is important for adequate functional and aesthetic results. This study evaluates the eponychial flap reconstruction technique in 45 fingertip amputations with loss of more than half the fingernail. In 33 cases the procedure was performed in combination with a palmar island flap for pulp reconstruction. Average follow up was 5 months. All eponychial flaps healed uneventfully. In 44 cases, the pulp volume was restored without nail growth disturbance. Five complications (9%) were observed (pain, soft nail, and nail deformity). Only one hook nail deformity required reoperation. All patients were satisfied with the aesthetic and functional outcome. We found eponychial flap fingernail reconstruction effective even for injuries proximal to the lunula and have extended the indication for this technique to very proximal fingernail defects. Eponychial flap reconstruction is a simple, safe, and time-effective technique without donor site morbidity. Simultaneous reconstruction of dorsal and palmar injuries should both be performed primarily resulting in the restoration of a satisfying fingertip.

Distraction osteogenesis and free nail graft after distal phalanx amputation

PURPOSE

To describe the results in patients treated with distraction osteogenesis combined with free nail graft after distal phalanx amputation.

METHODS

We analyzed 14 patients with distal phalanx amputation (13 women). Mean age was 35 years. There were 9 amputations of the index finger, 3 of the middle finger, and 1 each of the thumb and ring finger. We started bone distraction 7 days after surgery, with 1 mm distraction every 3 days. After bone elongation, we inserted a free composite nail graft at the dorsal tip of the distracted finger. We evaluated distraction length, consolidation time, aesthetic result (using the Foucher and Leclère score), and complications.

RESULTS

The mean bone elongation was 17 mm and mean consolidation time was 149 days. Nail cosmetic results were satisfactory; the mean total Foucher score was 14 out of 20. Mean individual scores were patient's opinion (7.8 out of 10), adequate length (1.2 out of 2.5), adequate alignment (1 out of 1), adequate width (1.8 out of 4), and dorsal scar quality (2.2 out of 2.5). The mean total Leclère score was 14 out of 20. All patients retained sensibility in the grafted area and none had healing abnormalities. The mean opinion about the donor site was 7.5 out of 8. Nail growth less than 50% occurred in 2 patients. Mean follow-up was 62 months.

CONCLUSIONS

Distraction osteogenesis combined with free nail graft is a therapeutic option when replantation is not an option or when it fails. However, treatment takes time and requires the involvement of the patient, family, and medical team.

Acellular dermal regeneration template for soft tissue reconstruction of the digits

PURPOSE

Trauma to the digits often leaves soft tissue defects with exposed bone, joint, and/or tendon that require soft tissue replacement. The objective of this study was to evaluate the effectiveness of acellular dermal regeneration template combined with full-thickness skin grafting for soft tissue reconstruction in digital injuries with soft tissue defects.

METHODS

Acellular dermal regeneration template was used to reconstruct digital injuries with exposed bone, joint, tendon, and/or hardware not amenable to treatment with healing by secondary intention, rotation flaps, or primary skin grafts. Acellular dermal regeneration template was applied to 21 digits in 17 patients. Nineteen digits had exposed bone, 8 digits had exposed tendon, 6 digits had exposed joints, and 2 digits had exposed hardware. The acellular dermal regeneration template was sutured over the soft tissue defect. Over 3 weeks, a neodermis formed. The superficial silicone layer of the acellular dermal regeneration template was removed, and the digits received full-thickness epidermal autografting with cotton bolster.

RESULTS

The duration of postoperative follow-up extended to a minimum of 12 months. For the injury sites where acellular dermal regeneration template was applied, the total area of application ranged from 1 cm(2) to 24 cm(2), with the largest individual site measuring 12 cm(2). Twenty of 21 digits demonstrated 100% incorporation of the acellular dermal regeneration template skin substitute. One digit that had sustained multilevel trauma developed necrosis requiring revision amputation. Full-thickness epidermal autografting was performed an average of 24 days after acellular dermal regeneration template skin substitute application and demonstrated a 100% take in 16 of 20 digits and partial graft loss of 15% to 25% in 4 of 20 digits that did not require further treatment.

CONCLUSIONS

Acellular dermal regeneration template combined with secondary full-thickness skin grafting is an effective method of skin reconstruction in complex digital injuries with soft tissue defects involving exposed bone, tendon, and joint. The neodermis increases tissue bulk and facilitates epidermal autografting with digital injuries that otherwise would require flap coverage or skeletal shortening of the digit.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Slowly adapting mechanoreceptors in the borders of the human fingernail encode fingertip forces

There are clusters of slowly adapting (SA) mechanoreceptors in the skin folds bordering the nail. These "SA-IInail" afferents, which constitute nearly one fifth of the tactile afferents innervating the fingertip, possess the general discharge characteristics of slowly adapting type II (SA-II) tactile afferents located elsewhere in the glabrous skin of the human hand. Little is known about the signals in the SA-IInail afferents when the fingertips interact with objects. Here we show that SA-IInail afferents reliably respond to fingertip forces comparable to those arising in everyday manipulations. Using a flat stimulus surface, we applied forces to the finger pad while recording impulse activity in 17 SA-IInail afferents. Ramp-and-hold forces (amplitude 4 N, rate 10 N/s) were applied normal to the skin, and at 10, 20, or 30 degrees from the normal in eight radial directions with reference to the primary site of contact (25 force directions in total). All afferents responded to the force stimuli, and the responsiveness of all but one afferents was broadly tuned to a preferred direction of force. The preferred directions among afferents were distributed all around the angular space, suggesting that the population of SA-IInail afferents could encode force direction. We conclude that signals in the population of SA-IInail afferents terminating in the nail walls contain vectorial information about fingertip forces. The particular tactile features of contacted surfaces would less influence force-related signals in SA-IInail afferents than force-related signals present in afferents terminating in the volar skin areas that directly contact objects.

Partial hand amputation and work

PURPOSE

To determine whether or not subjects who had had a partial hand amputation were able to return to the same job and whether or not they used their silicone finger prosthesis for work.

METHOD

Medical records of all the patients who had undergone a traumatic partial hand amputation and who had been treated in the Upper Limb Prosthetic Clinic at the Institute for Rehabilitation in Ljubljana were reviewed. Questionnaires were sent to 112 patients. Forty-eight questionnaires which were returned and had been correctly answered were analysed.

RESULTS

The study found that less than half the patients who had had a partial hand amputation were able to do the same work as before the amputation. Less than one-third wore their silicone prosthesis at work regularly. The subjects who did not have manual jobs and who had an amputation of only one or two fingers were able to keep the same job more easily after the amputation. Only a few subjects found their silicone prosthesis useful at work.

CONCLUSION

It can be concluded that partial hand amputation may present a great problem in keeping the same job after amputation. An aesthetic (cosmetic) silicone prosthesis is helpful particularly for subjects with higher education whose work involves personal contacts and for whom aesthetics is important. They use the prosthesis for certain activities, such as typing.