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Page 2 of 6 Cabrejo et al. Plast Aesthet Res 2023;10:1 https://dx.doi.org/10.20517/2347-9264.2022.30

Keywords: Carpal tunnel surgery, fat grafting, peripheral nerve

INTRODUCTION
Carpal tunnel surgery is one of the most common hand operations performed today . Within these cases,
[1]
the incidence of recurrent carpal tunnel ranges from 1% to 31%, with only about 5% of the reported cases
undergoing surgery . There are various reports in the literature regarding the best procedure for these
[2]
recurrent cases, including extensive external and internal neurolysis, various flap techniques, venous
wrapping, and prosthetic implants . Unfortunately, the literature does not include any comparative studies
[2]
that could conclude the best management of these patients. The main principles in revision surgery that
have been advocated include the addition of vascularized tissues to help nerves heal, adequate removal of
scarring around the nerve, and maintenance of adequate nerve gliding . One of the most novel methods
[3-5]
includes adding adipose derive stem cells as an adjunct to recurrent carpal tunnel release, yet the literature
includes small and contradictory reports .
[6,7]
Fat grafting is a method to deliver adipose-derived stem cells to the median nerve during carpal tunnel
release. Stem cell therapy’s effect on nerve regeneration has been studied extensively in the basic science
literature. Adipose-derived stem cells are the most practical as they can be harvested easily from patients
with a high yield of stem cells, about one million stem cells per gram of fat . The mechanisms proposed in
[8,9]
which adipose-derived stem cells aid in peripheral nerve injuries are: in situ differentiation to Schwann cells
and secretion of trophic and anti-inflammatory factors [10-15,16-20] . The studies demonstrate that the positive
effects of adipose-derived stem cells on peripheral nerve regeneration are mostly limited to animal
[21]
models .
There have been many studies using adipose-derived stem cells as a surgical treatment for nerve pain, and
[19]
the results are encouraging . Stromal vascular fraction was used to treat erectile dysfunction in 47% of
patients after radical prostatectomy . In a randomized controlled trial, patients with post-mastectomy pain
[22]
treated with fat grafting had an average pain reduction of 54.9% and also improved health-related quality of
[23]
life measurements . Among patients with neuropathic pain after burn injury, 6 out of 7 patients treated
with fat grafting had reduced pain and thus reduced consumption of pain medication .
[24]
In this study, we compare two modalities to treat recurrent carpal tunnel: (1) recurrent carpal tunnel release
only; and (2) recurrent carpal tunnel release with fat grafting. The goal is to assess subsequent improvement
in carpal tunnel syndrome using each method.

METHODS
The retrospective review of data was approved by Dartmouth Hitchcock Medical Center Institutional
Review Board, IRB# 020000917. All carpal tunnel surgeries performed by one surgeon, Dr. Joseph Rosen,
between July 2011 to October 2021 were reviewed. A recurrence of carpal tunnel syndrome was primarily
defined by clinical symptoms, the physical examination, electrical studies and willingness to undergo
surgery. Patients with nerve injury, transections, neuromas in continuity, etc., were excluded. All patients
underwent a nerve conduction study that ruled out other pathology, and about 88% of the patients in this
study had records that could be reviewed.

For all cases, patients underwent general anesthesia due to the need to harvest fat from the abdomen. The
recurrent carpal tunnel was treated with an open approach. The fat was harvested exclusively from the
abdomen using Coleman cannulas and purified with the Puregraft system and washed with lactated ringer’s