Do multiple physiological OCT biomarkers indicate age-related decline in rod mitochondrial function in C57BL/6J mice?

Purpose: To test the hypothesis that rod photoreceptor mitochondria function progressively declines over time.

Methods: 2, 12, and 24 month-old dark- and light-adapted C57BL/6J (B6J) mice were examined by OCT. We measured (i) an index of mitochondrial configuration within photoreceptors measured from the profile shape aspect ratio (MCP/AR) of the hyperreflective band posterior to the external limiting membrane (ELM), (ii) a proxy for energy-dependent pH-triggered water removal, the thickness of the ELM-retinal pigment epithelium (ELM-RPE), and its correlate (iii) the hyporeflective band (HB) signal intensity at the photoreceptor tips.

Video-Based Assessment of Microsurgical Trainees: An Evaluation of Gender Bias.

Background:  Gender bias in graduate medical evaluations remains a challenging issue. This study evaluates implicit gender bias in video-based evaluations of microsurgical technique, which has not previously been described in the literature.

Methods:  Two videos were recorded of microsurgical anastomosis; the first was performed by a hand/microsurgery fellow and the second by an expert microsurgeon.

Transducin-Deficient Rod Photoreceptors Evaluated With Optical Coherence Tomography and Oxygen Consumption Rate Energy Biomarkers.

Purpose: To test the hypothesis that rod energy biomarkers in light and dark are similar in mice without functional rod transducin (Gnat1rd17).

Methods: Gnat1rd17 and wildtype (WT) mice were studied in canonically low energy demand (light) and high energy demand (dark) conditions. We measured rod inner segment ellipsoid zone (ISez) profile shape, external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness, and magnitude of a hyporeflective band (HB) intensity dip located between photoreceptor tips and apical RPE; antioxidants were given in a subset of mice.

Functional Changes Within the Rod Inner Segment Ellipsoid in Wildtype Mice: An Optical Coherence Tomography and Electron Microscopy Study.

Purpose: To test the hypothesis that changing energy needs alter mitochondria distribution within the rod inner segment ellipsoid.

Methods: In mice with relatively smaller (C57BL/6J [B6J]) or greater (129S6/ev [S6]) retina mitochondria maximum reserve capacity, the profile shape of the rod inner segment ellipsoid zone (ISez) was measured with optical coherence tomography (OCT) under higher (dark) or lower (light) energy demand conditions. ISez profile shape was characterized using an unbiased ellipse descriptor (minor/major aspect ratio).

Passive Manipulation for Proximal Interphalangeal Joint Extension Contractures.

Purpose: We investigated closed passive manipulation as an alternative to surgery for certain proximal interphalangeal (PIP) joint extension contractures.

Methods: We retrospectively reviewed all patients with PIP joint extension contractures treated with passive manipulation at our institution between 2015 and 2019. The included patients were a minimum of 12 weeks from their initial injury/surgery (median 179 days; interquartile range: 130-228 days), had plateaued with therapy, and underwent a 1-time passive manipulation.

Achieving Functional Outcomes after Surgical Management of Catastrophic Vasopressor-induced Limb Ischemia.

Unlabelled: Vasopressor-induced limb ischemia is an unfortunate complication that can occur in patients treated for septic shock. Current literature lacks surgical treatment recommendations for this condition, besides amputation. We describe various reconstructive surgeries and functional outcomes in patients treated surgically for vasopressor-induced limb ischemia.

Comparison of 3 Dynamic External Fixation Devices for Proximal Interphalangeal Joint Dorsal Fracture-Dislocations in a Cadaver Model.

Purpose: Several improvised dynamic external fixation devices are used for treating unstable dorsal proximal interphalangeal (PIP) joint fracture-dislocations. We compared the effectiveness of 3 constructs for simulated dorsal PIP joint fracture-dislocations in a cadaver model.

Methods: We tested 30 digits from 10 fresh-frozen, thawed cadaver hands.

The Syringe External Fixator: Short- and Medium-Term Functional Outcomes From This Inexpensive and Customizable Treatment for Comminuted Intra-Articular Fractures of the Hand.

Purpose: Comminuted intra-articular fractures and fracture dislocations of the metacarpophalangeal (MCP) and interphalangeal joints are challenging. Dynamic external fixation, permitting early joint motion while still minimizing forces across the healing joint, can result in acceptable postoperative active range of motion (AROM). However, some fractures are not initially stable enough for early dynamic motion; further, many available dynamic external fixation systems are costly and cumbersome.

Long-Term Patency and Fluid Dynamics of Recipient Artery after End-to-Side Anastomosis for Free Tissue Transfer.

Background: End-to-end microvascular anastomoses sacrifice downstream inline perfusion of the recipient vessels. End-to-side anastomoses, in theory, maintain distal inline flow of the recipient vessel. The proposed benefit of the end-to-side technique depends on patency of the distal vessels and subsequent flow parameters, but maintenance of distal perfusion has not been conclusively demonstrated.

The Impact of Dividing the Flexor Tendon Pulleys on Tendon Excursion and Work of Flexion in a Cadaveric Model.

Purpose: The A2 and A4 pulleys of the flexor tendon system have traditionally been considered critical components of efficient digital flexion. This dogma has recently been challenged. Using fresh human cadaveric hands and a model to measure force and excursion, we sought to clarify the clinical importance of releasing different pulleys.

Locoregional Options for Acute Volar Pulp Fingertip Defects.

The volar fingertip is a unique anatomic structure, delicate yet durable, that allows us to navigate the world, acquire information from our surroundings, and express ourselves. Injuries to the volar finger can cause permanent dysfunction and should be taken seriously. In treating injuries of the volar fingertip, the surgeon has an opportunity to choose from a host of reconstructive options and provide the patient with an outcome suitable to their needs.

Syringe External Fixator: An Inexpensive Static-to-Dynamic Treatment for Comminuted Intra-Articular Phalangeal Fractures.

Comminuted intra-articular phalanx fractures are complicated injuries often treated with external fixation. The ideal external fixation system should be affordable, readily available, adaptable, and easy to use. The use of dynamic external fixation has advanced the care of these injuries but can be difficult to implement.

The Modified Vilkki Procedure: Vascularized Metatarsophalangeal Joint Transfer to Reconstruct a Full-Length Radius in Type III Radial Hypoplasia.

Radial longitudinal deficiency is a spectrum of deformity ranging from thumb hypoplasia to a shortened or absent radius. Traditional treatments are hindered by recurrent deformity and disruption of future forearm growth. These deficiencies can be addressed by a Vilkki procedure in which a free second toe metatarsophalangeal joint is used to restore a radial column and provide viable physes for continued forearm growth.

Reconstruction of digit planer injuries using component transfer of double second toes: A case report.

The purpose of this report is to show that customized component second-toe transfers may improve functional and aesthetic outcomes following bone, soft tissue, and joint destruction of traumatically injured digits. A 22-year-old male sustained a planer injury resulting in loss of the distal volar soft tissues of the middle, ring, and small fingers, along with variable destruction of middle phalanges and distal interphalangeal joints. Simultaneous vascularized second-toe transfers were performed with customized joint and pulp reconstruction of middle and small fingers.

Zone I Flexor Digitorum Profundus Repair: A Surgical Technique.

We present an all-inside technique for zone I flexor tendon repair that combines suture anchor fixation with buried back-up fixation. The back-up fixation uses transosseous tunnels and a dorsal counterincision to allow a suture tied dorsal to the distal phalanx and buried. This technique is strong and permits early active range of motion.

Microvascular Toe Joint for Proximal Interphalangeal Joint Replacement: Indications, Technique, and Outcomes.

Microvascular toe interphalangeal joint transfer can serve as a means of autogenous digit proximal interphalangeal joint (PIPJ) arthroplasty. Among surgical options for treating dysfunctional, absent, or destroyed PIPJs, free toe joint transfer is the most technically challenging and carries the greatest donor site cost to patients. Despite drawbacks, free toe joint transfer is a valuable tool with considerable advantages over conventional arthroplasty in the appropriate clinical setting.

The Effect of Skin Pigmentation on Determination of Limb Ischemia.

Purpose: Timely identification of tissue ischemia is critical, both in the traumatized limb and following free tissue transfer. The purpose of this study was to determine if skin pigmentation affects the ability to detect limb ischemia.

Methods: We conducted a study of healthy controls exposed to limb ischemia.

Structural basis for selectivity and diversity in angiotensin II receptors.

The angiotensin II receptors ATR and ATR serve as key components of the renin-angiotensin-aldosterone system. ATR has a central role in the regulation of blood pressure, but the function of ATR is unclear and it has a variety of reported effects. To identify the mechanisms that underlie the differences in function and ligand selectivity between these receptors, here we report crystal structures of human ATR bound to an ATR-selective ligand and to an ATR/ATR dual ligand, capturing the receptor in an active-like conformation.

Proximalization of the Vascularized Toe Joint in Finger Proximal Interphalangeal Joint Reconstruction: A Technique to Derive Optimal Flexion From a Joint With Expected Limited Motion.

When used to reconstruct a finger proximal interphalangeal joint, a free toe interphalangeal joint, without modification, cannot meet the motion demands of the finger to allow palm touchdown. This limitation is the direct result of the toe interphalangeal joint having an intrinsic arc of motion that delivers less flexion than that of a normal functioning finger proximal interphalangeal joint. By modifying the inset of the transferred joint to an extra-anatomical more proximal position, this limitation can be overcome.

Changes in Wrist Motion After Simulated Scapholunate Arthrodesis: A Cadaveric Study.

Purpose: A high incidence of nonunion and relatively poor outcomes with prior fixation techniques has precluded scapholunate (SL) arthrodesis as a standard treatment for SL instability. Our purpose was to determine the impact on range of motion (ROM) of simulated SL arthrodesis via headless screw fixation.

Methods: We performed baseline wrist ROM for 10 cadaveric wrists using a standardized mounting-and-weights system.

Inadvertent Intra-Arterial Drug Injections in the Upper Extremity: Systematic Review.

Purpose: To review the literature pertaining to inadvertent intra-arterial drug injection in the upper extremity, explore the various treatment options and their outcomes, and identify risk factors for limb amputation following intra-arterial injection.

Methods: A systematic review of Medline, EMBASE, and Cochrane databases (inception to March 2013) was completed for patients presenting with intra-arterial drug injection of the upper extremity. Details on intervention and outcome were extracted and subjected to pooled analysis with amputation as the primary outcome.

Coccidioidomycosis causing osteomyelitis of the hand in an immunocompetent patient.

Coccidioidomycosis osteomyelitis is a rare entity considered even more rare when identified in the immunocompetent patient. In non-endemic areas, the diagnosis of a fungus-causing osteomyelitis is often delayed or overlooked. This results in delayed or inappropriate treatment.