Proximal Plantar Plate of Lesser Toe Metatarsophalangeal Joint Vascular Supply

BACKGROUND

The plantar plate is a major stabilizing structure of the metatarsophalangeal (MTP) joint with instability frequently occurring after a tear or attenuation of this structure. Commonly, a McGlamry elevator is used to strip the plantar plate from the plantar surface of the metatarsal to improve exposure of the MTP joint. The anatomy of the proximal plantar plate and vascular consequence of stripping the plantar plate from the metatarsal is not yet well understood. The purpose of this study is to describe the proximal attachment of the plantar plate anatomically and quantify the relative contribution of blood supply to the proximal plantar plate from both the metatarsal and the plantar fascia.

METHODS

For anatomic evaluation, 6 lower extremity cadaver specimens without any gross evidence of foot and ankle deformity were utilized. For imaging analysis, 16 fresh frozen human adult cadaveric lower extremity specimens were used for this study, resulting in 35 MTP joints without deformity and 11 lesser MTP joints with cockup and/or crossover deformities. The specimens were prepared as described previously by Finney et al.⁵.

RESULTS

From gross anatomic dissection, the plantar plate origin consists of a stout fibrous pedicle distinct from the surrounding synovial-type tissue that firmly anchors the plantar plate to the metatarsal. Based on nano-computed tomographic imaging, an average of 63.5% of the vascular supply to the proximal portion of the plantar plate entered from the metatarsal pedicle. The remaining 36.5% of the vascular supply entered from the plantar fascia.

CONCLUSION

The proximal attachment of the plantar plate includes a stout fibrous pedicle anchoring the proximal portion of the plantar plate to the notch between the medial and lateral plantar condyles of the metatarsal head. The vascular supply of the proximal plantar plate is supplied from both the metatarsal pedicle and plantar fascia.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Vascular Supply to the Proximal Plantar Plate of Lesser Toe Metatarsophalangeal Joint is Primarily Supplied by the Attachment to the Metatarsal: A Nano-CT Microvasculature Study

Category:

Lesser Toes

Introduction/Purpose:

Lesser toe metatarsophalangeal (MTP) instability is implicated in common forefoot pain and deformities. The plantar plate is a major stabilizing structure of the MTP joint with instability frequently occurring after a tear or attenuation of this structure. Previous studies have demonstrated that the blood supply to the proximal plantar plate comes from both the metatarsal and the plantar fascia. Commonly, a McGlamry elevator is used to strip the plantar plate from the plantar surface of the metatarsal to improve exposure of the MTP joint. The vascular consequence of stripping the plantar plate from the metatarsal is not yet well understood. The purpose of this study is to quantify the relative contribution of blood supply to the proximal plantar plate from the metatarsal and plantar fascia.

Methods:

Twelve fresh-frozen human adult cadaver lower extremity specimens were utilized for this study, resulting in 35 lesser MTP joints that were studied. All specimens were between the ages of 18 and 65 years and had no history of diabetes, peripheral vascular disease, or connective tissue disorders. Specimens with a history of trauma to the foot or ankle, prior foot or ankle surgery, or evidence of clinical deformity of less toes upon inspection were excluded. The specimens were prepared as described previously in Finney et al. The anterior and posterior tibial arteries were perfused with a barium solution and counterstained with phosphomolybdic acid. The second through fourth MTP joints of 12 feet were imaged with nano-computed tomography (nano- CT) at 14-micron resolution. Reconstructed 3D and 2D CT images were utilized for analysis of the volume of vasculature along the metatarsal pedicle and plantar fascia of the proximal plantar plate.

Results:

Based on nano-CT imaging, the plantar plate specimen demonstrated microvascular infiltration at the proximal attachments of the metatarsal neck, interosseous muscles, periosteum, and plantar fascia (Figure 1). An average of 63.5% of the vascular supply to the proximal portion of the plantar plate entered from the metatarsal pedicle in 35 lesser toe specimens analyzed. The remaining 36.5% of the vascular supply entered from the plantar fascia. The second toes, third toes, and fourth toes had an average of 64.7%, 59.0%, and 67.1% of vasculature supply from the metatarsal pedicle, respectively. The average volume of vasculature from the metatarsal pedicle to the proximal plantar plate was 0.38 mm3, while the average volume of vasculature from the plantar fascia to the proximal plantar plate was 0.19 mm3.

Conclusion:

The vascular supply of the proximal plantar plate is supplied from both the metatarsal pedicle and plantar fascia. Using the McGlamry elevator for exposure of the MTP joint disrupts the dominant tributary for proximal plantar plate perfusion.

Management of a traumatic avulsion of the right upper lobe bronchus

Tracheobronchial injuries are rare but life-threatening and require early diagnosis, appropriate airway management, and emergent surgical intervention. We report a case of a post-traumatic, isolated avulsion of the right upper lobe bronchus in a 60-year-old woman involved in a pedestrian versus motor vehicle accident. After transfer from an outside hospital with a single lumen endotracheal tube and multiple right sided chest tubes with large air leaks, the patient was taken to the OR for bronchoscopy and surgical exploration. Intraoperatively, a complete avulsion of the right upper lobe was noted. Due to the extended time period from original injury and excellent reported functional status, our patient underwent completion lobectomy of the right upper lobe, primary bronchial repair, with an azygous vein flap.

Trends in acute ischemic stroke treatments and mortality in the United States from 2012 to 2018

OBJECTIVE

The establishment of mechanical thrombectomy (MT) as a first-line treatment for select patients with acute ischemic stroke (AIS) and the expansion of stroke systems of care have been major advancements in the care of patients with AIS. In this study, the authors aimed to identify temporal trends in the usage of tissue-type plasminogen activator (tPA) and MT within the AIS population from 2012 to 2018, and the relationship to mortality.

METHODS

Using a nationwide private health insurance database, 117,834 patients who presented with a primary AIS between 2012 and 2018 in the United States were identified. The authors evaluated temporal trends in tPA and MT usage and clinical outcomes stratified by treatment and age using descriptive statistics.

RESULTS

Among patients presenting with AIS in this population, the mean age was 69.1 years (SD ± 12.3 years), and 51.7% were female. Between 2012 and 2018, the use of tPA and MT increased significantly (tPA, 6.3% to 11.8%, p < 0.0001; MT, 1.6% to 5.7%, p < 0.0001). Mortality at 90 days decreased significantly in the overall AIS population (8.7% to 6.7%, p < 0.0001). The largest reduction in 90-day mortality was seen in patients treated with MT (21.4% to 14.1%, p = 0.0414) versus tPA (11.8% to 7.0%, p < 0.0001) versus no treatment (8.3% to 6.3%, p < 0.0001). Age-standardized mortality at 90 days decreased significantly only in patients aged 71-80 years (11.4% to 7.8%, p < 0.0001) and > 81 years (17.8% to 11.6%, p < 0.0001). Mortality at 90 days stagnated in patients aged 18 to 50 years (3.0% to 2.2%, p = 0.4919), 51 to 60 years (3.8% to 3.9%, p = 0.7632), and 61 to 70 years (5.5% to 5.2%, p = 0.2448).

CONCLUSIONS

From 2012 to 2018, use of tPA and MT increased significantly, irrespective of age, while mortality decreased in the entire AIS population. The most dramatic decrease in mortality was seen in the MT-treated population. Age-standardized mortality improved only in patients older than 70 years, with no change in younger patients.

Office-Based Intralesional Steroid Injection for Treatment of Laryngeal Sarcoidosis

OBJECTIVES

To report preliminary outcomes of a case series of in-office intralesional steroid injections for treatment of laryngeal sarcoidosis.

METHODS

After diagnosis of laryngeal sarcoidosis, 3 patients were offered in-office steroid injections for primary or adjunctive treatment. Triamcinolone 40 was injected into supraglottic sarcoidosis lesions in the office using a channel laryngoscope. Response to treatment and need for further injections was determined based on patient symptoms and repeat flexible laryngoscopy.

RESULTS

In-office intralesional steroid injections provided rapid symptom relief within days that lasted for months, thus decreasing the frequency of operative interventions. For one of the patients in this series, these injections even eliminated the need for tracheostomy. No complications were observed.

CONCLUSIONS

In-office intralesional steroid injection is an emerging adjunctive treatment for laryngeal sarcoidosis. Prospective studies are required to determine efficacy and long-term risk profiles in relation to the current standard of operative management and systemic treatments.

Scalable Synthesis of Multivalent Macromonomers for ROMP

The polymerization of functional monomers provides direct access to functional polymers without need for postpolymerization modification; however, monomer synthesis can become a bottleneck of this approach. New methods that enable rapid installation of functionality into monomers for living polymerization are valuable. Here, we report the three-step convergent synthesis (two-step longest linear sequence) of a divalent exo-norbornene imide capable of efficient coupling with various nucleophiles and azides to produce diversely functionalized branched macromonomers optimized for ring-opening metathesis polymerization (ROMP). In addition, we describe an efficient iterative procedure for the synthesis of tri-and tetra-valent branched macromonomers. We demonstrate the use of these branched macromonomers for the synthesis of Janus bottlebrush block copolymers as well as for the generation of bottlebrush polymers with up to three conjugated small molecules per repeat unit. This work significantly expands the scalability and diversity of nanostructured macromolecules accessible via ROMP.

Star PolyMOCs with Diverse Structures, Dynamics, and Functions by Three-Component Assembly

We report star polymer metal-organic cage (polyMOC) materials whose structures, mechanical properties, functionalities, and dynamics can all be precisely tailored through a simple three-component assembly strategy. The star polyMOC network is composed of tetra-arm star polymers functionalized with ligands on the chain ends, small molecule ligands, and palladium ions; polyMOCs are formed via metal-ligand coordination and thermal annealing. The ratio of small molecule ligands to polymer-bound ligands determines the connectivity of the MOC junctions and the network structure. The use of large M12 L24 MOCs enables great flexibility in tuning this ratio, which provides access to a rich spectrum of material properties including tunable moduli and relaxation dynamics.

Block Co-PolyMOCs by Stepwise Self-Assembly

We report a stepwise assembly strategy for the integration of metal-organic cages (MOCs) into block copolymers (BCPs). This approach creates "block co-polyMOC" (BCPMOC) materials whose microscopic structures and mechanical properties are readily tunable by adjusting the size and geometry of the MOCs and the composition of the BCPs. In the first assembly step, BCPs functionalized with a pyridyl ligand on the chain end form star-shaped polymers triggered by metal-coordination-induced MOC assembly. The type of MOC junction employed precisely determines the number of arms for the star polymer. In the second step, microphase separation of the BCP is induced, physically cross-linking the star polymers and producing the desired BCPMOC networks in the bulk or gel state. We demonstrate that large spherical M12L24 MOCs, small paddlewheel M2L4 MOCs, or a mixture of both can be incorporated into BCPMOCs to provide materials with tailored branch functionality, phase separation, microdomain spacing, and mechanical properties. Given the synthetic and functional diversity of MOCs and BCPs, our method should enable access to BCPMOCs for a wide range of applications.

TRNA2Gln Su+2 mutants that increase amber suppression

We selected mutants of lambda pSu+2 which had an increased ability to suppress on Escherichia coli trp B9601 amber mutation on translationally stringent rpsL594 streptomycin-resistant ribosomes. tRNA2Gin Su+2 molecules produced from eight independent mutants were purified, and their ribonucleic acid sequences were determined. Two types of mutations were mapped to the tRNA2Gin Su+2(glnV) gene by this method. Both altered the pseudouridine at position 37 of the tRNA anticodon loop. Seven of the isolates were transitions (pseudouridine to cytosine), and one was a transversion (pseudouridine to adenine). These mutations resulted in Su+ transfer ribonucleic acid molecules that exhibited higher transmission coefficients than their parent Su+2 transfer ribonucleic acids. As judged by their suppressor spectra on T4 amber mutants, which were almost identical to that of Su+2, the two mutant Su+ transfer ribonucleic acids inserted glutamine at amber sites.