Floor plan - 2013 Annual Meeting - American Association for Hand ...

The Use of Ultrasound to Identify the Position of the Digital Nerves of the Thumb
Institution where the work prepared: Henry Ford Hospital, Detroit, MI, USA
Kanye Willis, MD; Henry Ford Hospital; Donald Ditmars; Henry Ford Hospital
Purpose:
Trigger finger, also known as stenosing tenosynovitis, occurs when a digital flexor tendon sheath becomes constricted at the A-1 pulley.
The constriction is usually due to scar tissue or a nodule of the tendon sheath and results in pain, clicking of the finger with movement
and a digit that becomes locked in the flexed position. Surgical treatment consisting of dividing the A-1 pulley has a significantly
lower recurrence rate than medical treatment. Surgical treatment consists of a traditional open technique and a percutaneous
approach. The percutaneous approach employs the use of an 18 gauge needle guided anatomic landmarks to divide the A-1 pulley.
Several authors have discouraged performing percutaneous trigger finger release in the thumb due to the increased risk of injuring the
digital nerves. Our study uses ultrasound to identify the in vivo position of the digital nerves of the thumb in both flexed and extended
positions. We hypothesized that extending the thumb causes the digital nerves to move more laterally decreasing the risk of injuring
them during percutaneous trigger finger release.
Methods:
The study included 15 healthy subjects (7 male, 8 female) with a mean age of 29.5 years. An 8-megahertz frequency ultrasound probe
was used to identify the digital nerves of the right thumb. The distance between the digital nerves was measured with the thumb in
both flexed and extended positions. A single operator performed all ultrasound examinations using the same ultrasound equipment.
A comparison of the distance between the digital nerves with the thumb in flexion and extension was made.
Results:
On average there was a 1.4mm increase in the distance between the digital nerves when the thumb was placed in extension. This represents
a 12.6% increase in overall distance and reached statistical significance with a p-value of 0.01 using a T-test. Two subjects had a
decrease in the distance between the digital nerves when the thumb was extended, however the nerves appeared to be located more
inferiorly.
Conclusions:
Placing the thumb in extension results in lateral movement of the digital nerves in most patients, which may protect them during percutaneous
trigger finger release. Because individual variability exists, ultrasound may be a useful guide in identifying and protecting the
digital nerves when performing trigger finger release percutaneously. Future investigations may include using ultrasound to identify the
position of the digital nerve in multiple dimensions and in patients with comorbidities such as connective tissue disorders.
Peroneal Nerve Regeneration after End-to-Side Repair in Rat
Institution where the work was prepared: Poznan University of Medical Sciences, Poznaƒ, Poland
Piotr Czarnecki, MD; Aleksandr Astapov; Leszek Romanowski; Hand Surgery, Poznan University of Medical Sciences
Background:
En-to-side neuroraphy can be a solution for injuries with nerve gap when en-to-end or grafting techniques are not applicable. Current
experiences leave a lot of questions to this method of treatment.
Aim:
The aim of research is to evaluate: - effectiveness of end-to-side nerve repair, - the need of epineural window, - possible donor nerve damage.
Material and Method:
45 Wistar rats were divided into 3 equal groups: • end-to-side repair without epineural window, • end-to-side repair with epineural window,
• nerve graft reconstruction Right peroneal nerve were cut and then repaired according to the group investigated. Follow-up period
was 24 weeks and the regeneration was checked by: • footprint analysis after 1, 2, 4, 6, 8, 10, 12, 24 weeks, • electroneurography
after 24 weeks months using direct sciatic stimulation, magnetic field stimulation and both tibial and peroneal direct probing. Both
sides: operated and nonoperated were tested, • microscopic evaluation of tibial and peroneal nerve specimens after 24 weeks.
Results:
Footprint analysis Calculated factors prove on regeneration in every group investigated: SFI (A – -18,37, B – -15,15, C – -14,75); PFI (A -
-20,95, B - -21,17, C - -20,8); TSI (A – 0,08, B – 0,06, C – 0,06) after 3 months, values has decreased after 6 months. The highest values
were in graft repair group, the lowest in the group without epineural window. Electroneurography In both direct and magnetic stimulation
amplitude, latency and conduction velocity were in normal range in every group investigated. Amplitude and latency of peroneal
nerve were higher on operated side.
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