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Cabrejo et al. Plast Aesthet Res 2023;10:1 https://dx.doi.org/10.20517/2347-9264.2022.30 Page 3 of 6

solution. The fat was injected around the median nerve without damaging the nerve. Post-operatively,
patients were not splinted and were encouraged to become physically active as soon as tolerated. Patient
follow-up appointment notes were reviewed and evaluated for symptoms and discussion of treatment
options, including re-operation. The study groups were compared utilizing a t-test, setting significance at
P < 0.05.

RESULTS
In this review, the recurrent carpal tunnels treated thus far, excluding explicit nerve injury such as
transections, neuromas in continuity, etc., totaled 81 cases. Statistical comparison between demographic
variables demonstrated no statistical differences [Table 1]. About 80% of the patient had motor latencies
4.2 ms or absent at the wrist and 68% had sensory latencies 3.6 ms or absent at the wrist. The rate of
improving symptoms for performing a carpal tunnel release was only 50.0% and for performing carpal
2
tunnel release with fat grafting was 92%, the Pearson χ was 17.1, and P-value < 0.00 [Table 2]. The average
amount of grafted fat injected into the wrist was about 5.4 ± 3.8 mL. On average, patients presented with an
initial recurrence at about 6.25 ± 0.91 years after their initial surgery. Patients were followed for an average
of 1.4 ± 0.2 years after revision surgery. Improvement in symptoms was defined as improvement in clinical
symptoms and no further scheduled or performed surgery.

In terms of complications, we had one case of cellulitis and another patient presented with significant pain
in the abdomen after surgery, a computerized tomography (CT) scan showed no abnormal pathology and
the patient recovered.

DISCUSSION
Fat grafting as an adjunct to recurrent carpal tunnel surgery has been reported by various case series in 2000
and later in 2015 . The initial study demonstrated no difference in adding fat grafting and the latter
[8,9]
demonstrated a dramatic improvement. Our study is larger in scope and followed for a longer period and
fat grafting as an adjunct to treatment continued to improve outcomes for patients. Similar to previous
studies, recurrent carpal tunnel release continued to improve symptoms in about 50% of patients.

The suspected mechanism of action is the differentiation of adipocyte-derived stem cells into Schwann cells
and the release of trophic and anti-inflammatory factors [10-15] . These studies are based on work on animal
models of nerve injury, yet there is no study correlating these hypotheses to the actual improvement in
clinical studies.

One of the difficulties of these cases is the definition of recurrent carpal tunnel. Patients present with similar
symptoms as before and sometimes after a period of improvement. Test such as electrical studies does not
always correlate with symptomatology, about 25% of patient in this study demonstrated clinical symptoms
without positive electrical studies . In this study, it was general clinical symptomatology and physical exam
[25]
presentation that prompted offering the patient further treatment. There is also a heterogenous assortment
of techniques of the original carpal tunnel release, including endoscopic carpal tunnel release. The
overwhelming majority of the recurrent carpal tunnel patients came from external referrals; therefore, the
data is incomplete regarding the initial presentation of symptoms and overall evaluation. Even though these
factors make the data less “clean” in terms of making statistical conclusions, it is the reality presented in the
clinic for hand surgeons.