Sarcon, Aida K.

ABSTRACT Extracellular vesicles (EVs) are non‐replicating, lipid membrane‐bound nanoparticles released by most eukaryotic cells into the extracellular space. When derived from platelets, a subset of EVs can exhibit remarkable anti‐inflammatory and antioxidant properties, making them attractive candidates to attenuate sterile inflammatory states such as limb skeletal muscle ischaemia‐reperfusion injury (IRI). Peripheral extremity IRI complicating acute limb revascularisation procedures, replantation of major traumatic amputations and limb allotransplants can trigger a life‐threatening reperfusion syndrome that leads to multi‐organ system failure and death. In this study, we used a platelet‐derived EVs‐enriched preparation as a therapeutic strategy for extremity IRI. To allow for a clinically translatable drug delivery strategy, we established and validated a catheter‐directed regional intra‐arterial limb infusion (RLI) delivery approach that permitted selective and effective targeting of pEVs to limb skeletal muscles and soft tissues in the vascularly isolated rodent extremity simulating pre‐reperfusion preservation and revascularisation conditions of the ischaemic or amputated extremity. In addition to being safe and feasible, we demonstrated robust retention of EVs by skeletal muscles of the operative limb during the early critical phase of reperfusion injury following RLI. We also show that pretreatment of ischaemic skeletal muscles using an pEVs‐enriched formulation just before reestablishing extremity blood flow alleviated metabolic derangements and suppressed the systemic and localised proinflammatory cytokine response associated with skeletal muscle reperfusion and reduced histologic markers of myofibre injury without adverse effects on serum chemistries. This work opens a new perspective to investigate novel approaches for regional delivery of therapeutic pEVs to skeletal muscle to mitigate limb IRI in vivo, and to achieve both in situ and ex vivo targeted delivery of nanocarriers to the isolated limb tissue for other therapeutic applications.

Abstract The purpose of this study was to evaluate the incidence and outcomes of traumatic lunate fractures in a Level I trauma center over a 20-year period. Traumatic lunate fractures are rare, making it difficult to determine their frequency, outcomes, and patterns in clinical practice. A retrospective evaluation of 57 patients was conducted at a single institution from 2000 to 2022. Imaging studies, including radiographs, computed tomography, and magnetic resonance imaging, were reviewed to confirm traumatic etiology and fracture pattern. Fifty-seven lunate fractures met inclusion criteria: 11 were isolated and 46 had associated carpal fractures. Treatment included immobilization in 31 patients and surgery in 26. At a mean follow-up of 20.5 months (range, 2–186), average wrist flexion–extension range of motion was 90 degrees (range, 45–160), and grip strength averaged 26 kg (range, 6–48). Patient-reported outcomes were collected at a mean of 105 months (range, 12–226), with mean scores of 27 for the Disabilities of the Arm, Shoulder, and Hand, 19 for the Patient-Rated Wrist Evaluation, and 77 for the Mayo Wrist Score. Complications included 25 cases of posttraumatic arthritis, 2 cases each of avascular necrosis (AVN), nonunion, and complex regional pain syndrome, and 1 hardware infection. Posttraumatic arthritis was more frequently observed in patients with dorsal intercalated segment instability (DISI), age over 50 years, and displaced fractures. Lunate fractures occur in conjunction with greater arc injuries. Volar pole fractures were the most common fracture type observed. Predictors of long-term osteoarthritis included age over 50 years, DISI deformity, and displaced fractures at the time of diagnosis. Surgical fixation methods resulted in comparable outcomes. Two lunates progressed to AVN, both of which occurred following open operative fixation. Prognostic, Level IV

Summary: Umbilical piercings are popular among young individuals for aesthetic body enhancement. However, umbilical piercings can lead to complications such as infections, hypertrophic scarring, and epithelialized tracts that require surgical intervention. This case report presents a novel, minimally invasive technique using a lacrimal probe and iris scissors under local anesthesia to excise the epithelialized piercing tracts. A 23-year-old patient underwent the procedure, resulting in minimal scarring and high satisfaction at an 11-month follow-up. Compared with the existing methods, this approach ensures complete tract removal while preserving the natural umbilical contour. Given the limited literature, this technique offers an effective solution with excellent cosmetic outcomes.

Abstract To present our clinical experience with a volar scapholunate (SL) ligament reconstruction using a strip of the long radiolunate ligament. This was a single-institution observational study (2004–2022) of SL ligament injuries with evidence of a torn volar component on arthroscopy that received volar capsulodesis with/without a dorsal repair. The postoperative range of motion (ROM), grip strength, complications, and secondary surgery (e.g., four-corner fusion or total wrist fusion), and radiographic changes were reported. Disabilities of arm, shoulder, and hand/patient-rated wrist evaluation (DASH/PRWE) scores were prospectively collected. Patients were stratified by static versus dynamic/predynamic SL diastasis and by isolated volar versus volar and dorsal ligament injury. Twenty-eight patients (15 females and 13 males) with a mean age of 35.1 years (± 15.7) met the inclusion criteria. The follow-up was 86.3 months (± 53.4; minimum 11 months). Most (26/28) patients were right-handed. The majority (20/28) of the patients presented ≥ 6 weeks postinjury. Few (4/28) used tobacco. Most (20/28) patients had dynamic/predynamic injuries. Postoperatively, the mean pronation/supination was 83 degrees/83 degrees, flexion/extension was 56 degrees/61 degrees, ulnar deviation was 30 degrees, and radial deviation (RD) was 19 degrees (n = 13). The mean grip strength was 78.8% (± 30.4) of the contralateral normal side (n = 14). Except for increased RD in patients with dynamic/predynamic injuries (p = 0.02), there were no other ROM differences. SL widening (>3 mm) postoperatively was observed in 33.3% (2/6) of static versus none of the dynamic/predynamic injuries (p = 0.165). There were only two postoperative complications, both surgical site infections. Two patients had persistent pain and required secondary surgery at a median of 48 months. At 86.9 months, patients reported a mean DASH of 16.4 (± 17.8) and a PRWE of 24.6 (± 23.6), and 78.9% (15/19) returned to prior work. We report long-term functional outcomes after a volar capsulodesis for volar SL injuries. This appears to be a safe procedure with an acceptable complication rate and low disability after 7 years. Most (approximately 79%) patients returned to their previous employment. A larger comparative study will be required to prove superiority to other types of repairs. Level IV, Case series.

Background: The authors present a novel microsurgical model to investigate ischemia-reperfusion (I/R) injury in composite tissue (muscle/skin) using a musculocutaneous flap. I/R was induced in a rodent biceps femoris musculocutaneous flap through collateral ligation and arteriovenous clamping. The authors hypothesized that I/R flaps would show greater tissue damage compared with sham. Methods: Male rats were randomized into I/R ( n = 10) and sham ( n = 9) groups. The I/R group underwent flap elevation, collateral ligation, 3 hours of arteriovenous clamping, followed by reperfusion. The sham group had flap elevation only. Perfusion was monitored using laser-speckle imaging, and flap discoloration was assessed with blinded skin ischemia necrosis scores. Serum and the composite tissue (skin/muscle) were analyzed for injury on postoperative days (PODs) 1 or 3. Results: Clamping reduced perfusion ( P = 0.00), whereas unclamping increased perfusion ( P <0.00). Over time, flaps exposed to I/R were more ischemic (estimate, 0.39; P = 0.02). At POD1, the injury group had higher serum creatine kinase ( P = 0.04) and potassium ( P = 0.00) than the sham group. The injury group had more muscle apoptosis (34.7% versus 5.2%; P = 0.03), myonecrosis (30.3% versus 14.1%; P = 0.04), and inflammation (13.7% versus 4.9%; P = 0.02) than the sham group; myonecrosis and inflammation persisted into POD3. Skin apoptosis and inflammation were similar. Conclusions: This model reliably reproduces I/R injury with a 3-hour ischemic period followed by early reperfusion. Animals subjected to the authors’ technique showed greater tissue damage than the sham group, with muscle being more vulnerable than skin. Serum showed peak muscle injury at 24 hours, and histologic analysis showed myonecrosis and inflammation through 72 hours. This suggests that less than 24 hours’ reperfusion (eg, critical window) may serve as the optimal time for possible intervention. Clinical Relevance Statement: I/R injury is a complex phenomenon affecting vascular composite tissues. The mitochondrial superoxide dismutase may be more specific for I/R injury. There may be a critical window within which to mitigate injury (<24 hours after reperfusion). The authors’ model helps investigate muscle/skin I/R injury.

Chronic proximal interphalangeal (PIP) joint instability is a rare and difficult problem to treat, with the main options including collateral ligament reconstruction and joint arthrodesis. To date, there are minimal described techniques for collateral ligament reconstruction. We describe a novel technique utilizing a slip of the flexor digitorum superficialis (FDS), harvested through a single minimal incision. This technique can be used for collateral ligament reconstruction with multiple applications, including chronic recurrent PIP joint dislocations and instability during PIP joint arthroplasty.

ABSTRACT Long segment losses exceeding 10 cm in the sciatic nerve are challenging in both the reconstructive techniques and optimizing sensory and motor function recovery. This case report and literature review describes our experience of using a pedicled vascularized common peroneal nerve graft to repair a 14‐cm sciatic nerve defect, involving L4 , L5 , and S1 nerve roots. Additionally, we conducted a literature review of various types of nerve autografts for large sciatic nerve defects, summarizing their characteristics and outcomes to aid clinicians in decision‐making and expected results in different scenarios. The patient, a 23‐year‐old female diagnosed with neurofibromatosis type I, underwent R0 tumor resection of the proximal left sciatic nerve due to a malignant peripheral nerve sheath tumor. She received an ipsilateral pedicled vascularized common peroneal nerve graft. The reconstruction included the L4 , L5 , and S1 nerve roots beyond the greater sciatic foramen into the inner pelvis. The patient's postoperative course was uneventful. At the 26‐month follow‐up, she showed MRC grade 4/5 strength in hamstrings with 90°knee flexion and a steady gait pattern. At the 32‐month follow‐up, she could ambulate very well with an ankle‐foot orthosis. The outcomes support the use of a pedicled vascularized common peroneal nerve graft in a single‐staged surgery to restore motor function for large sciatic nerve defects. Our literature review revealed that in cases where sural nerves are insufficient or injured for sciatic nerve reconstruction, the common peroneal nerve is a viable alternative to help patients regain functional independence.

Abstract Rhabdomyolysis following revascularization of the ischemic upper extremity can lead to life- & limb- threatening sequelae. In the context of replantations and vascularized composite allografting, a reconstructive procedure usually reserved for upper limb amputees, prolonged tissue ischemia is detrimental to extremity functional recovery. Currently, validated survival small animal models of extremity reperfusion injury that permit longitudinal assessment of limb function are lacking. To date, studies that evaluated reperfusion injury-induced neuromuscular impairment rely on terminal ex vivo procedures and do not provide clinically translatable measurements. Furthermore, it is unclear if upper extremity musculature exhibits a different ischemic threshold compared to the lower limb given the relatively rare incidence of upper limb ischemia. Here, we present a reliable rat model of extremity post-reperfusion syndrome (PRS) that comprehensively recapitulates the biochemical hallmarks of rhabdomyolysis secondary to upper extremity reperfusion injury and allows for monitoring in vivo upper limb function using clinically relevant electrodiagnostic and kinematic metrics. In addition to inducing severe metabolic derangements, our forelimb PRS provided insights on gross motor and electrophysiological alterations upper extremity reperfusion injury. We identify gait coordination parameters such as stride frequency and forelimb-hindlimb coordination index and electrophysiological metrics including compound muscle action potential amplitude as objective, non-invasive outcome measures for limb function assessment in small animal models of extremity PRS. This comprehensive, validated functional model can serve as an invaluable tool to evaluate therapeutics or preconditioning regimens to attenuate PRS and mitigate resulting neuromuscular dysfunction.

ABSTRACT Introduction Acute Compartment Syndrome (ACS) is a severe trauma caused by elevated intra-muscle-compartment pressure (ICP). The current standard method for diagnosis is to insert a needle into the muscle sterilely under anesthesia. However, to secure the environment is sometimes not easy and leads to delays in diagnosis. Recently, we have focused on shear wave ultrasound elastography (SWE) as an alternative, which can be done concisely in unclean environment and without anesthesia. We would like to report the usefulness of SWE for ACS diagnosis using 2-pedal walking turkey model recently developed in our lab. Materials and Methods A total of 32 1-year-old Bourbon turkeys were used. 5% solution of chicken albumin was infused continuously into the tibialis cranialis (TC) muscle using IV pump. The ICP was increased stepwise from 0 to 50 mmHg. During the rising of ICP, the correlation between values of SWE (kPa) and ICP (mmHg) was measured. After the ICP reached 50 mmHg, half of the turkeys were maintained at this pressure for 2 hours and the rest for 6 hours. After infusion, a fasciotomy was performed on the half turkey. Half of the turkeys were euthanized after 2 weeks and the rest after 6 weeks. SWE of TC muscle and walking gait data on turkeys using a portable walkway system were measured weekly until euthanasia. At euthanasia, isometric tetanic muscle force (ITF) tests to TC muscle and histological evaluations were performed. Results SWE value (kPa) was highly significantly correlated to the actual ICP (mmHg) (R2 = 0.91). Stance of ACS side leg were significantly extended, and swing of the control side shortened from the second to the third week after ACS in the 6 hours infusion-no-fasciotomy group (P &lt; 0.05*). ITF was significantly reduced mainly in the 6 hours infusion group (P &lt; 0.05*). Histological evaluation revealed that in the 6 hours infusion and 6 weeks survival group, both the muscle fiber and intercellular distances were significantly expanded (P &lt; 0.05). Conclusion SWE seems to be a substitute measure of ICP in diagnosing ACS. With regard to our in vivo ACS model using turkey, survival at 50 mmHg ICP for 6 hours and 6 weeks post ACS would be an appropriate situation.