Fingertip injuries Flashcards
1
Q
Describe the anatomy of the finger tip
A
- defined as distal to the insertion of the FDP and terminal tendon
- volar skin is thicker, glaborous skin, with thicker stratum corneum
- pulp is fibro-fatty padding on volar aspect of finger tips for grip, pinch - maintained to distal phalanx by fibrous septae
- dorsal skin is thinner, non glaborous skin wiht minimal subucutaneous tissue
- dorsally there is the nail structure: perionychium, nail plate, germinal matrix, sterile matrix, hyponychium
- arterial supply trifurcates at DIPJ and sends a dorsal branch to nail fold, branch to tip, and to pulp
- there are glomus bodies which are AV shunts that are regulated sympathetically for temperature control
- veins are small, dorsal venules are extremely small until level of DIPJ
- nerves travel volar to arteries, both together below grayson ligament and above cleland ligament
- in mid-proximal phalanx, the nerve sends a dorsal branch to the dorsal middle and distal phalanx/digit
- at DIPJ the nerve also trifurcates, sending branches to nail fold, tip and pulp
- the pulp is richly innervated for sensory perception
2
Q
what is the lanula?
A
- lanula is the hypopigmented convex crescent seen at the proximal extent of the nail plate
- it indicuates persistent giant nuclei of cells of germinal matrix
- distal to lanula underlying nail bed is sterile matrix, generally not responsible for nail growth/production
3
Q
DESCRIBE NAIL GROWTH
A
- at the germinal matrix, onychocytes (nail producing cells) undergo proliferation, enlarge, the nucleus disintegrates, cells collapse and flatten; major role to contribution of keratin content
- at the dorsal roof of the nail fold, the same process occurs as in germinal matrix, but cells lose their nuclei more quickly, also adds shine
- along the sterile matrix there is some contribution to growth (< 10%), whereby further squamous cells are added to add strength, thickness; contributes only minor keratin and contributes to nail adhereence to bed
4
Q
describe classification of fingertip injuries
A
- many described / eponymous classification system
- useful classification system will outline involved/injuried structures as follows:
- geometry of injury
- transverse
- volar/dorsal/lateral oblique
- Soft tissue/skin/pulp injured
- Nail plate injured/involved; proximal or distal to lanula (defines involvement of germinal matrix)
- Bone exposed in wound
- Tendon exposed/injured
- Joint involved
5
Q
describe treatment goals for fingertip injury
A
- provide durable soft tissue coverage
- preserve sensation
- preserve length
- preserve nail appearance and function, prevent hook nail
- expedite return to work/leisure
- minimize discomfort during healing
6
Q
List the options available to reconstruction of fingertip injuries
A
- secondary intention
- 1’ closurewith suture approximation
- skin graft
- composite graft
- homodigital flap
- heterodigital flap
- regional flap
- microsurgical transfer or replantation
7
Q
discuss the use of healing by secondary intention w fingertip injries: indications, advantages, disadvantages, expected outcomes
A
- for defects < 1.5cm^2 (some say w no exposed volar bone)
- advantages: better sensation, glaborous skin, no donor morbidity, inexpensive, no secdonary joint stiffness or contracture from positioning while healing
- disadvantages: time to complete healing and return to work, hypersensitivity or dysesthesia, unstable scar (particularly if insufficient bony padding)
- expected outcomes: most healed within 3-6 wks; most back to full manual labour by 6-8 wks, aesthetic outcome acceptable (superior)
8
Q
discuss the use of skin grafts for coverage of fingertip injuries: indications, advantages, disadvantages, expected outcomes
A
- for injuries not amenable to 2’ intention and patient unable/unwilling to tolerate local/regional flap
- often taken from hypothenar eminence so glabour skins - FT graft (reinnervation possible)
- adv: easy, relatively fast, minimal donor morbidity, no contracture d/t position while healing
- disadv: often does not achieve protective sensation, may not expedite healing vs. 2’ intention
9
Q
discuss the use of composite grafts for fingertip reconstruction: indications, adv, disadv, expected outcomes
A
- children < 6-8years (best in < 2 years)
- adv: glaborous skin, optimize appearance, no donor morbidity, no contracture w position during healing, preserve length /avoid revision amputation
- disadv: unreliable healing/take with increased age, potential for stiff/flat/tough, painful, minimially sensate tip depending on extent of revascularization, risk of total failure
10
Q
what are factors to consider with fingertip injuries of soft tissue and exposed bone, when comparing use of flaps vs revision amputation
A
- significant exposed bone precludes use of 2’ intention, skin grafting, +/- composite graft
- options become loco-regional flap vs. revision amputation
- revision amputation
- adv: early return to work, functional outcomes often similar, avoid contracture w/ positioning during healing, no donor site morbidity
- disadv: loss of length, worst cosmetic result, patient psychosocial impact of amputation and stump
- ideal for digits where length is less criticial (D2, 4, 5) or for patients that wish to return to work asap
- locoreginal flap
- adv: optimal to preserve length, may preserve/restore sensation depending on flap, improved cosmesis vs. rev-amp, patient psychosocial outcome to avoid shortening or amputated appearance
- disadv: donor site morbidity, may require sub-optimal position during healing and subsequent stiffness/contracture, protective sensation may or may not be achieved, cortical re-learning in adults rarely achieved
- ideal to preserve length of thumb or long finger
11
Q
Define the perionychium
A
Composed of
- nail bed
- nail fold
- nail plate
12
Q
What structures make up the nail fold, plate and bed
A
Nail bed:
- Sterile matrix
- germinal matrix
- dorsal roof
- Lunula
Nail fold (Eponychium)
- dorsal roof
- ventral floor
- proximal mail plate
13
Q
WHat is the hyponichium
A
At junction of distal nail and epidermis of tip
= large mass of WBC and keratin
Fx: mechanical and immunological barrier
14
Q
What is the function of the nail plate
A
- protection
- tactile sensation
- thermoregulation
- cosmesis
15
Q
What are options for local/regional flap for fingertip injuries (>1cm2 with bone exposure)
A
- V-Y advancement (atasoy)
- lateral V-Y advancement (kutler)
- Dorsal reverse adipofascial flap
- cross finger
- reverse cross finger
- Thenar flap
- Homodigital neurovascular island flap
- homodigital reverse FDMA flap
- Heterodigital neurovascular island flap
