Journal of Hand Surgery - June 2022 - S274

S274
Journal of Hand Surgery (Eur) 47(Supplement 1)
Conclusions: Hypoallergenic methods demonstrated
the lowest contact force on skin and may be a lower
risk option with skin contract of 0.8mmHg measured
at 500 grams of longitudinal traction.
A-1420 Arthroscopic Management of
Scapho-trapezio-trapezoidal Joint Arthritis: A
12-years Review of Local Case Series and cadaveric
study of a new STT dorso-radial portal
Jeanette Wen Ching Ting1,2, Henry Pang1, Wing Lim Tse1,
Pak Cheong Ho1, Chu Kay Michael Mak1 and
Wai Ping Fiona Yu3
1Department of Orthopaedics and Traumatology, Prince of
Wales Hospital, Hong Kong SAR, China
2Department of Surgery, Prince of Wales Hospital, Hong
Kong SAR, China
3Department of Orthopaedics and Traumatology, The
Chinese University of Hong Kong, Hong Kong SAR, China
Introduction and Objectives: Surgical management
of isolated scapho-trapezio-trapezoidal joint (STTJ)
arthritis via open approaches is widely described in
the literature. However, arthroscopic management of
symptomatic STTJ arthritis is less well known. We
present here our 12-years clinical experience of
STTJ arthroscopic debridement and pyrocarbon
implant insertion. We also performed a cadaveric
study of a new STT dorso-radial portal which
allows for increased working space and easier
instrumentation compared to the traditional STT-R
and STT-U portals.
Methods: We describe a clinical case series from
2008 to 2020 in patients with isolated STTJ arthritis.
Pre- and Post-op X rays and/or MRI were reviewed
for presence of STTJ arthritis, CMCJ arthritis and
DISI deformity. Clinical profile including demographic
data, pain scores and functional scores were
retrieved from electronic records. For the cadaveric
study, we dissected and measured the dorso-radial,
STT-U and STT-R portal distance from important
neurovascular structure including radial artery and
superficial radial nerve.
Results: A total of 13 STTJ arthroscopies were performed
from 2008-2020 in 10 patients (mean age: 67
years old, range: 57-84 years old, Male: 20%). All of
them had predominant STTJ arthritis with relatively
sparing CMCJ. 60% STTJ arthritis was predominant
in the right side, 30% left side, and 10% bilaterally.
7 arthroscopic debridement were performed, and
6 arthroscopic pyrocarbon implants were inserted.
All patients had improvement in pain and functional
scores on follow-up. Our cadaveric studied showed
that the STT dorso-radial port was 3.63mm away
from the superficial radial nerve whilst the mean
distance from the nerve to STT-U port was much
closer at 2.50 mm. The STT dorso-radial port was
2.61mm away from the radial artery whilst the
STT-R was further away at 6.25 mm.
Conclusion: Out of the 7 patients received debridement
as the first operation, 70% had satisfactory pain
improvement without further treatment required,
whereas the rest of 30% patients required pyrocarbon
implantation. There was no complication in all
cases of STTJ arthroscopy with or without pyrocarbon
implants. This study shows that not only arthroscopic
management is a feasible and safe approach
for patients with STTJ arthritis, the use of the
STT-dorsoradial port can be used for safely and
effectively.
A-1425 Development of long term multisite
optogenetic stimulation device and precise
rehabilitation after cC7 transfer in TBI: an in vivo
mice study
Su Jiang1, Mingjie Zhou1, Xiaomin Wang1, Yuanting Xie2,
Jiayi Zhang2 and Wendong Xu1
1the department of hand surgery, Huashan Hospital,
Shanghai, China
2State Key Laboratory of Medical Neurobiology and MOE
Frontier Center for Brain Science, Institutes of Brain
Science, Fudan University
Background: Cerebral hemisphere injury can lead to
unilateral upper limb spastic paralysis, long-term
disability and pain, accompanied by dyskinesia,
muscle atrophy and other problems. And the clinical
effect of the commonly used clinical treatment methods
is limited. Previously, our team presented the
contralateral seventh cervical nerve (cC7) transfer
operation, which has greatly improved the function
of the affected limb. However, the precise control
ability of patients after cC7 transfer operation still
needs to be further improved. For this purpose, we
developed an implantable multisite optogenetic
stimulation device (MOSD), which can provide multisite
optogenetic stimulation at different stages after
cC7 transfer and promote axon regeneration.
Methods: Firstly, we choose atmega328p-mu microcontroller
chip as the main module of MOSD, which
is used to control 8 mini-LEDs. And we finally use
M31CL with PDMS to package the wireless MOSD,
which can still work normally 3 months after implantation
in mice. Secondly, we designed a multisite
optogenetic stimulation driver and the corresponding
FPC adapter board. And we tested the time accuracy
of the driver to control the mini-LED and the working
temperature of MOSD. Next, immunohistochemical
staining was used to test the regeneration of the
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