Can a bioactive interbody device reduce the cost burden of achieving lateral lumbar fusion?

OBJECTIVE: Intervertebral devices are increasingly utilized for fusion in the lumbar spine, along with a variety of bone graft materials. These various grafting materials often have substantial cost burdens for the surgical procedure, although they are necessary to overcome the limitations in healing capacity for many traditional interbody devices. The use of bioactive interbody fusion devices, which have demonstrable stimulatory capacity for the surrounding osteoblasts and osteoprogenitor cells and allow for osseointegration, may reduce this heavy reliance on osteobiologics for achieving interbody fusion. The objective of this study was to evaluate the rate of successful interbody fusion with a bioactive lateral lumbar interbody titanium implant with limited volume and low-cost graft material. METHODS: The authors conducted a retrospective study (May 2017 to October 2018) of consecutively performed lateral lumbar interbody fusions with a bioactive 3D-printed porous titanium interbody device. Each interbody device was filled with 2-3 cm3/cage of a commercially available ceramic bone extender (ß-tricalcium phosphate-hydroxyapatite) and combined with posterior pedicle screw fixation. No other biological agents or grafts were utilized. Demographic, clinical, and radiographic variables were captured. Fusion success was the primary endpoint of the study, with graft subsidence, fixation failure, and patient-reported outcomes (Oswestry Disability Index [ODI] and visual analog scale [VAS]-back and -leg pain scores) collected as secondary endpoints. The authors utilized a CT-based fusion classification system that accounted for both intervertebral through-growth (bone bridging) and ingrowth (integration of bone at the endplate-implant interface). RESULTS: In total, 136 lumbar levels were treated in 90 patients. The mean age was 69 years, and 63% of the included patients were female. Half (50.0%) had undergone previous spinal surgery, and a third (33.7%) had undergone prior lumbar fusion. A third (33.7%) were treated at multiple levels (mean levels per patient 1.51). One year after surgery, the mean improvements in patient-reported outcomes (vs preoperative scores) were -17.8 for ODI (p < 0.0001), -3.1 for VAS-back pain (p < 0.0001), and -2.9 for VAS-leg pain (p < 0.0001). Bone bridging and/or appositional integrity was achieved in 99.3% of patients, including 97.8% who had complete bone bridging. No fixation loosening or implant failure was observed at any segment. Low-grade graft subsidence (Marchi grade ≤ I) occurred in 3 levels (2.2%), and intraoperative endplate violation occurred twice (1.5%). High-grade subsidence was not found. No implant failure or revision surgery for pseudarthrosis/subsidence was necessary. CONCLUSIONS: The use of bioactive titanium interbody devices with a large surface footprint appears to result in a very high rate of effective fusion, despite the use of a small volume of low-cost biological material. This potential change in the osteobiologics required to achieve high fusion rates may have a substantially beneficial impact on the economic burden inherent to spinal fusion.

Flexible Nail Treatment of Pediatric Both-Bone Forearm Fractures.

SUMMARY: Although most pediatric both-bone forearm fractures are treated nonoperatively, some do require surgical fixation. This article and accompanying step-by-step technique video demonstrate intramedullary fixation of a both-bone forearm fractures in a 7-year-old boy.

Are Orthopaedic Surgery Residency Applicants Making an Impact? A Bibliometric Evaluation of Applicants.

Orthopaedic surgery is one of the most competitive surgical specialties in the United States. No investigation has focused on the impact of research productivity and reputation on matching in this applicant pool. A retrospective investigation evaluating publications was conducted on residency applicants to the department of orthopaedic surgery of a single institution in 2019. Predictors of successful matching in orthopaedic surgery were analyzed. Of 519 candidates, 314 (60.5%) reported publications on their applications at the time of submission. The mean impact factor of reported publications was 3.6 (95% CI 0-11.8) and did not differ between candidates who did (3.4 [95% confidence interval [CI] 0-12.2]) and did not (3.4 [95%CI 0-8.0]) match, (p = 0.90). An applicant's participation in research, number of publications, publications in higher impact journals, or misrepresentation of their publications had no effect on successful orthopaedic residency match. (Journal of Surgical Orthopaedic Advances 30(3):150-155, 2021).

Postoperative Hemiplegic Migraine After a Laparoscopic Cholecystectomy: A Case Report.

We report the case of a 35-year-old woman who developed severe right-sided hemiplegia and hemisensory loss shortly after emergence from general anesthesia for a laparoscopic cholecystectomy. Her medical history was significant for migraine with aura and a family history of transient hemiparesis thought to be a result of a transient ischemic attack. The patient's deficits slowly resolved, and she was ultimately diagnosed with familial hemiplegic migraine after a negative workup for cerebrovascular accidents.

Luminescence spectroscopy of matrix-isolated atomic manganese: site size and orbital occupancy dependence of crystal field splitting.

Narrow linewidth emission features observed in the near-UV following y (6)P state excitation of atomic manganese isolated in the solid rare gases are assigned to b (4)D and a (4)P states. These states arise from the 3d(5)4s(2) electronic configuration, identical to that of the (6)S ground state, and the origin of the narrow linewidths. Two thermally stable sites, labeled blue and red on the basis of their position in absorption spectra, are occupied by atomic Mn in Ar and Kr while a single site is present in Xe. The red site produces a single, narrow line emission for the b (4)D state at 329 nm. In contrast, a lineshape analysis of the complex blue site b (4)D state emission between 331 and 332 nm reveals the occurrence of three zero phonon lines (ZPLs). Millisecond emission decay curves recorded for these features are found to be complex, requiring double and triple exponential fit functions. The origins of the complex decays and multiple ZPLs are shown to arise from weak crystal field splitting (CFS) of the J=7/2 spin-orbit level of the b (4)D state of atomic Mn isolated in the blue site of the solid rare gases. Fields of cubic symmetry are capable of inducing splitting for J>3/2 so atoms isolated in both single vacancy and tetravacancy sites in the fcc lattices of the solid rare gases are prone to this effect. b (4)D state emission is also produced following y (6)P excitation for Mn atoms occupying the red sites in Ar and Kr. However, Mn atoms isolated in the larger tetravacancy sites have small matrix shifts and do not exhibit any CFS. The magnitudes of the weak CF splittings are shown to depend on both the excited state electronic configurations 3d(5)4s(2) b (4)D and 3d(6)4s(1) a (4)D states and the size of the matrix site occupied by atomic Mn.

Investigations of the optical spectroscopy of atomic sodium isolated in solid argon and krypton: experiments and simulations.

The absorption spectra of thin film samples, formed by the codeposition of sodium vapor with the rare gases have long been known to consist of complex structures in the region of the atomic sodium "yellow-doublet" lines. The photophysical characteristics of the associated luminescence (excitation/emission) spectra, indicate strong interaction between the excited P state Na atom and the rare gases (Ar, Kr, and Xe) used as host solids. This system is reinvestigated with new experimental spectroscopic results and molecular dynamics (MD) calculations. The so-called "violet" site in Ar and Kr has been produced by laser excitation of thermally deposited samples. The simulation of the "spray-on" deposition of thin films enables identification of tetravacancy (tv) sites of isolation for ground-state atomic sodium in Ar while in Kr this site is found in addition to single vacancy (sv) occupancy. Various cubic symmetry sites were taken into account to simulate absorption and emission spectra using accurate interaction potentials for the Na.RG diatomics. The well-known 3-fold splitting in absorption, attributed to the Jahn-Teller effect, was very well reproduced but the simulated spectra for all the sites considered are located in the low energy region of the experimental bands. The evolution of the excited state Na atom is followed revealing the nature and symmetry of the sites that are transiently occupied. Consistent with the large Stokes shift observed experimentally, there is an extensive rearrangement of the lattice in the excited state with respect to the ground state. Combining all the experimental and theoretical information, an assignment of experimental violet, blue, and red absorption features is established involving single vacancy, tetravacancy, and hexavacancy sites, respectively, in Ar and Kr.

New insights on the photodissociation of N-methylpyrrole: the role of stereoelectronic effects.

We investigated the reaction dynamics of N-methylpyrrole (NMP) along the N-CH3 coordinate, upon excitation energies below 6.4 eV. Ours and previous experiments show clearly the existence of different reaction channels leading to slow and fast fragment production whose relative efficiency fluctuates with the changes in the excitation energy. Thanks to our modeling based on the differences of the NMP molecular orbitals (MOs) with respect to those of pyrrole we are able to show the existence of two low lying dissociative pi sigma(N-CH3)* states. Those states originate from the degeneracy removal in the pi MOs owing to their interaction with the sigma(CH) MO of the methyl group. This evidence and the calculated potential energy surfaces for dissociation along the N-CH3 coordinate provide the correct framework for the interpretation of the details in the NMP photodissociation dynamics.

Luminescence spectroscopy of matrix-isolated atomic manganese: excitation of the "forbidden" a6D(J)<-->a6S transitions.

Laser-induced excitation spectra recorded for the electric-quadrupole 3d(6)4s a6D(J)<--3d(5)4s2a6S(5/2) transitions of atomic Mn, allow assignment of the red emission features, previously observed in Mn/RG (RG=Ar, Kr and Xe) matrices with resonance 3d(5)4s4pz6P(5/2)<--3d(5)4s2 a6S(5/2) excitation, to the metastable a6D(9/2) state. Narrow excitation bands recorded for the red site in the Mn/Kr system allow identification of all five spin-orbit levels (J=1/2, 3/2, 5/2, 7/2 and 9/2) in the a6D state. The coincidence of the lowest energy excitation band and the observed 585.75 nm (17,072 cm(-1)) emission band of atomic Mn in Kr matrices, yielded a definitive assignment of this emission to a transition from the J=9/2 spin-orbit level. Temperature dependent emission scans lead to the identification of the zero phonon line for the a6D(9/2)-->a6S(5/2) transition at 585.75 nm. The identified matrix-shift of +20 cm(-1) allows an assessment of the extent of the ground state stabilization in the red (secondary) site of atomic Mn isolation in solid Kr. Emission produced with direct a6D state excitation yielded both the 585.75 and 626 nm features. The former band arises for Mn atoms occupying the red site--the latter from blue site occupancy in solid Kr. The excitation linewidths recorded for these two sites differ greatly, with the blue site yielding a broad featureless profile, in contrast to the narrow, structured features of the red site. The corresponding red site a6D(J)<-->a6S(5/2) transitions in Ar and Xe matrices are broader than in Kr--a difference considered to originate from the site sizes available in these hosts and the interatomic Mn x RG potentials. The millisecond decay times recorded for the red emission bands in the Mn/RG systems are all much shorter than the 3 s value predicted for the gas phase a6D(9/2)-->a6S(5/2) transition. This enhancement allows optical pumping of the forbidden a6D(J)<-->a6S transitions with low laser powers when atomic manganese is isolated in the solid state. However all the emission decays are complex, exhibiting triple exponential decays. This behavior may be related to the dependence of the excitation linewidths on the J value, indicating removal of the J degeneracy due to weak matrix-induced, crystal field splitting.

Luminescence spectroscopy of matrix-isolated z 6P state atomic manganese.

The relaxation of electronically excited atomic manganese isolated in solid rare gas matrices is observed from recorded emission spectra, to be strongly site specific. z 6P state excitation of Mn atoms isolated in the red absorption site in Ar and Kr produces narrow a 4D and a 6D state emissions while blue-site excitation produces z 6P state fluorescence and broadened a 4D and a 6D emissions. MnXe exhibits only a single thermally stable site whose emission at 620 nm is similar to the broad a 6D bands produced with blue-site excitation in Ar and Kr. Thus in Ar(Kr), excitation of the red site at 393 (400) nm produces narrow line emissions at 427.5 (427.8) and 590 (585.7) nm. From their spectral positions, linewidths, and long decay times, these emission bands are assigned to the a 4D72 and a 6D92 states, respectively. Excitation of the blue site at 380 (385.5) nm produces broad emission at 413 (416) nm which, because of its nanosecond radiative lifetime, is assigned to resonance z 6P --> a 6S fluorescence. Emission bands at 438 (440) and 625 (626.8) nm, also produced with blue-site excitation, are broader than their red-site equivalents at 427.5 and 590 nm (427.8 and 585.7 nm in Kr) but from their millisecond and microsecond decay times are assigned to the a 4D and a 6D states. The line features observed in high resolution scans of the red-site emission at 427.5 and 427.8 nm in MnAr and MnKr, respectively, have been analyzed with the W(p) optical line shape function and identified as resolved phonon structure originating from very weak (S=0.4) electron-phonon coupling. The presence of considerable hot-phonon emission (even in 12 K spectra) and the existence of crystal field splittings of 35 and 45 cm(-1) on the excited a 4D72 level in Ar and Kr matrices have been identified in W(p) line shape fits. The measured matrix lifetimes for the narrow red-site a 6D state emissions (0.29 and 0.65 ms) in Ar and Kr are much shorter than the calculated (3 s) gas phase value. With the lifetime of the metastable a 6D92 state shortened by four orders of magnitude in the solid rare gases, it is clear that the probability of the "forbidden" a 6D --> a 6S atomic transition is greatly enhanced in the solid state. A novel feature identified in the present work is the large width and shifted 4D and 6D emissions produced for Mn atoms isolated in the blue sites of Ar and Kr. In contrast, these states produce narrow, unshifted (gas-phase-like) 4D and 6D state emissions from the red site.

The absorption and excitation spectroscopy of matrix-isolated atomic manganese: sites of isolation in the solid rare gases.

This study collects information from absorption and luminescence excitation spectra recorded for Mn atoms isolated in the solid rare gases Ar, Kr, and Xe and presents an analysis of the site occupancy, based on the polarizabilities of the rare gases and the observed spectral shifts. Two thermally stable sites of isolation exist for atomic Mn in solid Ar and Kr, while a single thermally stable site is present in Mn/Xe. Site occupancy assignments are based on the application of a polarizability model to the z (6)P(5/2)<--a (6)S(5/2); z (8)P(5/2)<--a (6)S(5/2), and y (6)P(5/2)<--a (6)S(5/2) electronic transitions of atomic Mn. From an analysis of the observed RG matrix-to-gas phase energy shifts for P<--S type transitions, this model allows the association of certain site types occupied by metal atoms in the rare gas solids. The required condition being a linear dependence of the matrix shifts with rare gas polarizability for those metal atoms "trapped" in a particular site type. Application of the polarizability model in conjunction with trends observed in site dominance, established a connection between the blue sites in Ar and Kr and the single site in Xe. Use of the known MgRG ground state bond lengths facilitated an identification of the sites of Mn atom isolation assuming the transference of the known MgRG bond lengths to the MnRG systems. Substitutional site occupancy of atomic Mn is assigned to the blue sites in Ar and Kr and the single site in Xe, while tetra-vacancy site occupancy is assigned to the red sites in Ar and Kr. Consistent with these assignments, Mn atoms in solid Ar show a preference for trapping in tetra-vacancy sites whereas in solid Kr, single substitutional sites are preferred and in Xe, this is the only site observed.