20240517 Replantation - Dr Jeff

When performing a replant of an amputated finger, which of the following is the correct order of surgery?

• A. Bone, Artery, Extensor, Flexor, Nerve, Vein

• B. Artery, Bone, Vein, Extensor, Flexor, Nerve

• C. Artery, Bone, Extensor, Flexor, Vein, Nerve

• D. Bone, Extensor, Flexor, Artery, Nerve, Vein

• E. Bone, Extensor, Flexor, Artery, Vein, Nerve

Answer explanation

A useful way of remembering it is BE a FAN of V. A stable platform is needed for reconstruction. Then the deep structures must be repaired before the delicate arterial and nerve repairs

All of following are absolute indication to replantation in the hand EXCEPT?

• A. Amputation of multiple digits

• B. Thumb amputation

• C. Amputation at the level of the palm

• D. Single digit amputation distal to the flexor digitorum superficialis insertion

• E. Isolated amputation of little finger proximal to flexor digitorum superficialis in a child

Answer explanation

A single digit amputation distal to the flexor digitorum superficialis (FDS) insertion is a RELATIVE indication for replantation, NOT an absolute indication.

Absolute indications for replantation include thumb amputations, multiple digit amputations, amputations at the level of the wrist or palm and any amputation in a child. The aforementioned injuries result in significant loss of hand function and are therefore a priority for surgical repair. Although replantation of single digit amputations is rarely indicated, amputations distal to the FDS insertion have been found to have good functional results after replantation. As such, these injuries are a relative indication for replantation

All of the following factors are favorable for digit survival after replantation surgery EXCEPT?

• A. Sharply amputated digit

• B. Crushed amputated digit

• C. Warm ischemia time of 8 hours

• D. Patient age of 10 years

• E. Female gender

Answer explanation

Waikakul et al. in a study of 1018 replantations found that type of injury was the most important factor influencing immediate and late outcome. Extensively crushed injuries had the worst outcome, followed by degloving and avulsion injuries. Sharp cut injuries fared the best. Regular cigarette smoking resulted in poor immediate survival rate and prolonged ischemia had a significant influence in final functional outcome, but neither were as important as mechanism of injury. Alcohol consumption was also a negative predictor. Favorable factors for replantation survival were female gender, age under 13 years old, and nonsmokers. Regarding ischemia time, <12 hours of warm ischemia or <24 hours of cold ischemia for a digit to obtain optimal outcomes

A 34-year-old male undergoes a thumb replantation after an industrial meat slicer accident. At 4 hours postoperatively there is a drop from 33 degrees Celsius to 29 degrees Celsius and the pulse oximetry monitor on the thumb reads 87%. All of the following are treatment options for the management of his arterial inflow insufficiency EXCEPT:

• A. Administer IV heparin

• B. Administer a stellate ganglion block

• C. Placement of leeches on the thumb

• D. Inspect the dressing for any constriction

• E. Place the thumb in a dependent position

Answer explanation

Arterial thrombosis after digit replantation typically occurs within the first 12 hours postoperatively whereas venous thrombosis/congestion occurs after the first 12 hours postoperatively. Leeches excrete Hirudin, which is 100 times more potent than heparin, but are typically used for the treatment of venous thrombosis/congestion and not arterial thrombosis. Miller's review states a drop in temperature >2 C in 1 hour or temperature below 30 C indicates decreased digital perfusion. If arterial insufficiency develops: release constrictive bandages, place the extremity in a dependent position, consider heparinization, consider stellate ganglion blockade, or explore early if these maneuvers do not work.

A 34-year-old male sustains amputations of the 4th and 5th fingers at the level of the middle phalanx after cutting them with a butcher knife. Which of the following techniques would most likely increase total surgical time during replantation?

• A. Utilizing an on-call surgical team experienced at digit replantations

• B. Digit-by-digit repair method

• C. Structure-by-structure repair method

• D. Bone shortening procedures to avoid the need for vein grafts

• E. Obtaining a thorough inventory of the digit structures that are deficient and the structures that are available for reconstruction

Answer explanation

Surgical time in multiple digit replantation is increased by digit-by-digit repair techniques and decreased by structure-by-structure repair techniques. The Level 5 article by Morrison and McCombe reviews the indications and results of finger replantation. Results of replantation from the DIP to PIP joint typically have good outcomes whereas replantations at the proximal interphalangeal (PIP) joint to MCP joint have poor outcomes due to flexion contractures. The review article by Wang cites that tenolysis and tendon procedures were needed in 47.2% of the published cases of digit replantation and is the leading type of secondary operation. The classic article by Waikakul et al reviewed 1018 digital replantations in 552 patients. They had a 92% rate of successful outcome and found that type of injury was the most important factor influencing immediate and late outcome.