Place In Space Research Articles

Simulation Study on Fire Visibility of Typical Floor Planes of Modern Super High-Rise Office Buildings in China

With the development of office forms, the space form of super high-rise office buildings changed from the unitary efficient office space to a complex space that integrated office, communication, and experience, which also diversified the design of typical floors in the office zone. However, from the perspective of fire prevention, the placement of shared space changed the form of the plane in typical floors in the office zone, affecting the smoke spreading of fire and paths of personnel evacuation. Hence, the subject on the planar relationship among high-rise office buildings based on fire prevention analysis, which optimizes space design, is worthy of discussion. After collecting many cases of super high-rise office buildings in China, this study categorized them into six typical planes and adopted the software PyroSim for comparative simulation of the smoke spreading of fire. By comparing the visibility of different zones in fires, this study analyzed the effects of the area of the office zone, the location of the atrium, and the form of the plane on the fire visibility on the typical floor and put forth the key factors that influence fire visibility, thus optimizing the plane design of the typical floor of super high-rise buildings. The findings show that in the six fire scenes, the area of the office zone is between 1136m2 and 1736m2. The peak of duration for visibility decline at 1.5 m appeared in Scene 3. Its office zone is 1536m2, and the duration of visibility decline is greater than 1000 s. In other fire scenes, the duration of visibility decline is less than 300 s. By comparing the plane arrangement features of the fire scenes, the paper concludes that in a given fire scene, establishing an atrium in the office zone, expanding the length of the adjacent edge between the atrium and the office zone, and building an evacuation corridor between the atrium and the core tube can greatly extend the effective evacuation time. This can serve as reference for the plane design of super high-rise office buildings.

Element chtoniczny w bułgarskiej obrzędowości cyklu wiosennego

<p>Przedmiotem analizy w niniejszym artykule są bułgarskie wiosenne obrzędy wypędzenia insektów, gadów, drapieżników i gryzoni oraz zapewniające ochronę przed nimi zakazy i działania magiczne (symboliczne zamykanie, zaszywanie, zalepianie zwierzęcych pysków / oczu). Ujmując obrzęd w kategoriach tekstu kultury, szczególną uwagę zwrócono na relacje między jego warstwą rytualną (czynność, jej wykonawca i obiekt, użyty rekwizyt, osadzenie w czasie i przestrzeni) a werbalną (towarzyszące czynności słowa). Ekscerpowane teksty folkloru (formuły wypędzenia będące komentarzem do podejmowanych działań rytualnych) zostały omówione pod kątem ich zróżnicowania strukturalnego.</p>

Tracing the Ephemeral: Mapping Young Children’s Running Games

Young children’s play is highly multimodal, with gesture, gaze, movement and speech often combined simultaneously in collaborative meaning-making. This article argues for a multimodal social semiotic perspective on play, recognising that this requires representation of data that brings multimodal elements into careful consideration. In this article, multimodal transcription is used to examine a video recording of three and four-year-old children playing a chasing game in an English nursery school. Map-like transcripts, including an animated transcript, are used to document an instance of their play, drawing particular attention to placement in space over time. Whilst such moments of play may at first appear fleeting and chaotic, multimodal transcription reveals the communicative, creative and agentive capacities of young children in a multitude of forms. The transcripts highlight and make evident the ways in which roles and rules of play are carefully negotiated moment-by-moment in multiple modes. In this way, map-like multimodal transcripts are presented as devices to highlight meaning-making where it may not normally be looked for, seen or recognised.

What You Seek Is Who You Are: An Applied Spatial Model of Newspapers’ Ideological Slant

In recent years, the news media landscape has been characterized by two distinct patterns: a decline in newspaper circulation, and a persistent degree of ideological slant in newspapers’ position. We explore a possible nexus between these two phenomena by means of a model that extends some recent developments in the empirical spatial theory of voting to the reader’s choice with respect to newspapers. We assume that ideological proximity to a newspaper affects the choice made by a consumer to read it. Newspapers will then compete among themselves to maximize their respective readerships by finding an optimal placement in the ideological space. However, newspapers can also decide to target readers of a specific type. As we will show, this is a crucial step to take into consideration. We empirically apply our model to the Italian case. We show that Italian newspapers appear largely to behave as theoretically expected. However, the “ideological force” behind this conclusion must be sought in newspapers’ competition with respect to that subset of readers which can be identified as regular ones. This result highlights a possible mechanism driving a persistent newspaper ideological slant in time of lower newspaper circulation.

An accessibility spatial search algorithm to optimize defibrillator deployment in indoor space

ABSTRACT Indoor space, where humans spend 80% of their lives, is subject to frequent out-of-hospital cardiac arrest (OHCA). Optimizing the spatial deployment of automated external defibrillators (AEDs) has the potential to improve OHCA survival rate. Complex indoor space is typically divided by hard barriers into multiple discrete subspaces across floors. Commonly used distance measurements, such as Euclidean distance and network distance, are unsuitable for indoor AED deployment. Instead, we propose an accessibility spatial search algorithm (ASSA) to generate accessible areas of candidate facilities, i.e. AEDs, based on an indoor space model, and optimizes the facility deployment subject to three objectives: maximizing the survival rate, maximizing total spatial coverage and maximizing backup coverage. Additionally, improved artificial bee colony (ABC) algorithm is used to solve the optimization problem. We design experiments with simulated and real-world scenarios for AED placements and evaluate the ASSA results. The experiments show that the ASSA can provide helpful guidance in optimizing AED placement in indoor space.

Virtual Spacer Implantation Platform Based on Finite Element Method for Simulation and Planning Patient-Specific Spacer Placement

In recent years, due to major advances in radiotherapy (RT) delivery systems, more attention is paid to integrating RT into cancer management. Efficacy of advanced RT techniques like stereotactic body radiation therapy is shown for lung, liver, prostate and pancreas cancer. Use of RT, however, can be limited due to proximity of organs at risk (OARs). Previous studies show dosimetric benefits of spacers, namely dose escalation and increasing OAR sparing, to make separation between target and OARs for prostate and recent studies for pancreas. Yet, dosimetric benefits of placement of spacer highly depend on location and shape of spacer implanted. Accordingly, purpose of our study is to reduce geometric uncertainties of spacer placement by presenting a simulation platform that generates an optimized plan for spacer implantation. Pre- and post-spacer paired computed tomography (CT) are acquired. Gross target volume (GTV) and OARs are delineated by physician, as well as, spacer in the post-injection CT. Data is anonymized and fed into our simulation platform to create finite element model (FEM) of spacer placement process and simulate using finite element analysis (FEA). In this study, location of spacer is determined by post-injection CT for validation. To do so, pre- and post-injection CTs are registered by a rigid registration method while bones and later head of pancreas and prostate are used as landmark. To ensure the accuracy and convergence of FEA, anatomical and physical properties of organs are considered as a set of patient-specific boundary conditions. Finally, result of FEA is interpreted as deformations of 3D CT images and structures. To evaluate performance of simulation, we utilized overlap volume histogram (OVH) thresholds, L3cc and L9cc defined as overlapping tumor and OAR volume at 3mm and 9mm expansion of GTV, while introducing Distance Angular Histogram (DAH) to assess spatial performance of our method. 4 cases of hydrogel spacer are included in this study: 2 prostate and 2 pancreas cases. Applicable to any type of spacer, we used hydrogel cases for validation due to considerably higher level of biomechanical complexity. OVH thresholds (L3cc and L9cc) are similar for virtual and post injection cases, and considerably lower compared to pre-injection (table_1). Further, DAH shows that distribution of distance between tumor and OAR is more than a simple shift, and thus, closer to reality. Although spacer can improve RT outcome, its use is impeded by uncertainties associated with placement procedure. Our virtual spacer platform is aimed to help planning placement of spacer and obviate uncertainties of using it. Future studies will focus on improving performance and integration to real-time ultrasound guided procedure.Tabled 1Abstract 2678; TableOVH MetricL3mmL9mmSitesPancreasProstatePancreasProstateCasesABCDABCDPre-Injection0.0050.015000.0700.1600.0200.126Post-Injection00000.0140.0140.0050.004Virtual Spacer00000.0190.0120.0010.005 Open table in a new tab

Biological Effective Dose (EBD) in Analysis of Rectal Dose in Prostate Cancer Patients Undergoing a Combination Therapy of EBRT and LDR With Hydrogel Spacer Insertion

To evaluate rectal wall doses sparing in prostate cancer patients undergoing combination therapy of external beam radiotherapy (EBRT) and low-dose-rate (LDR) brachytherapy with hydrogel spacer insertion. Fifty-five patients were enrolled in this retrospective study, in which 25 patients were applied with injection of polyethylene-glycol hydrogel and others without the insertion as control. Patient was prescribed with EBRT in dose of 45Gy to primary tumor site and nodal regions over 25 fractions, and LDR in dose of 100Gy on prostate. Two weeks after spacer placement, patient underwent CT scan for VMAT planning. Intraoperative prostate seed (Pd-103) implant (PSI) was performed two weeks after EBRT completed. Doses to the target and rectal wall were examined in each plan. BED calculation was applied in evaluation of sum dose of the rectal wall in each patient according to AAPM TG-137. On average, 1.04cm interspace between prostate and rectum was achieved by spacer insertion. Rectal wall was defined as 0.4cm thickness inside of rectum contour, and the volume was in average of 13.9cm3 in patients with spacer and 12.6cm3 in those without spacer. Target dose coverage was not seen in significant difference in VMAT and PSI plans between two groups of the patients. In VMAT plan, rectal wall doses were in average of 44.8Gy, 43.6Gy, 42.3Gy, 40.0Gy and 28.8Gy to the volume of 0.1, 0.5, 1, 2 and 5cm3, respectively, in patients with no spacer. In patients with spacer, the doses reduced significantly in average of 42.7Gy, 39.9Gy, 37.7Gy, 34.2Gy and 24.5Gy to rectal volume of 0.1, 0.5, 1, 2 and 5cm3, respectively (p<0.01 or <0.05 in t-test). In postimplant dosimetry, in patient without spacer, rectal wall doses were in average of 129.1Gy, 84.2Gy, 64.8Gy, 43.8Gy and 15.3Gy to the volume of 0.1, 0.5, 1, 2 and 5cm3, respectively. In patient with spacer, the doses decreased to 46.3Gy, 35.3Gy, 28.8Gy, 21.1Gy and 9.3Gy to rectal wall volume of 0.1, 0.5, 1, 2 and 5cm3, respectively. Dose decrease in the volume 0.1 - 5cm3 was significant in patients with spacer, compared with those without insertion (p<0.01 or <0.05 in t-test). Calculation of BED was performed in order to evaluate sum dose of the rectal wall in combination of both VMAT and PSI plans. In patient without spacer, BEDsum was in average of 126.9Gy, 106.7Gy, 84.3Gy and 45.5Gy to rectal volume of 0.5, 1, 2 and 5cm3, respectively. In contrast, BEDsum was seen in decrease of 20% to 39% in patient with spacer, in which was 76.8Gy, 68.2Gy, 57.2Gy and 36.2Gy to the rectal volume of 0.5, 1, 2 and 5cm3, respectively. Insertion of hydrogel spacer significantly improved rectal dose sparing, about 20% to 39%, in prostate cancer patient in EBRT and LDR combination therapy.

Incidence of peripheral nerve injury in revision total shoulder arthroplasty: an intraoperative nerve monitoring study

The incidence of nerve injuries in revision total shoulder arthroplasty (TSA) is not well defined in the literature and may be higher than that in primary procedures, with 1 study reporting a complication rate of 50% for shoulder revisions. Given that continuous intraoperative nerve monitoring (IONM) can be an effective tool in diagnosing evolving neurologic dysfunction and preventing postoperative injuries, the purpose of this study was to report on IONM data and nerve injury rates in a series of revision TSAs. A retrospective cohort review of consecutive patients who underwent revision TSA was performed from January 2016 to March 2020. Indications for revision included infection (n = 7); failed total arthroplasty and hemiarthroplasty secondary to pain, dysfunction, and/or loose components (n = 36); and periprosthetic fracture (n = 1). Of the shoulders, 32 underwent revision to a reverse TSA, 6 underwent revision to an anatomic TSA, and 6 underwent spacer placement. IONM data included transcranial electrical motor evoked potentials (MEPs), somatosensory evoked potentials, and free-run electromyography. The motor alert threshold was set at ≥80% signal attenuation in any peripheral nerve. Patients were screened for neurologic deficits immediately following surgery, prior to administration of an interscalene nerve block, and during the first 2 postoperative visits. Additional data collection included surgical indication, sex, laterality, age at surgery, procedure performed, body mass index, history of tobacco use, Charlson Comorbidity Index, medical history, and preoperative range of motion. A total of 44 shoulders in 38 patients were included, with a mean age of 63.2 years (standard deviation, 13.0 years). Of the procedures, 22.4% (n = 10) had an MEP alert, with 8 isolated to a single nerve (7 axillary and 1 radial) and 1 isolated to the axillary and musculocutaneous nerves. Only 1 patient experienced a major brachial plexus alert involving axillary, musculocutaneous, radial, ulnar, and median nerve MEP alerts, as well as ulnar and median nerve somatosensory evoked potential alerts. Age, sex, body mass index, Charlson Comorbidity Index, and preoperative range of motion were not found to be significantly different between cases in which an MEP alert occurred and cases with no MEP alerts. In the postoperative period, no minor or major nerve injuries were found whereas distal peripheral neuropathy developed in 4 patients (9.1%). Among 44 surgical procedures, no patients (0%) had a major or minor nerve injury postoperatively and 4 patients (9.1%) complained of distal peripheral neuropathy postoperatively. In this study, we have shown that through the use of IONM, the rate of minor and major nerve injuries can be minimized in revision shoulder arthroplasty.

Subacromial Balloon Spacer for Massive, Irreparable Rotator Cuff Tears Is Associated With Improved Shoulder Function and High Patient Satisfaction

To investigate associations between clinical and demographic parameters and Constant-Murley (CM) scores after subacromial balloon placement for massive, irreparable rotator cuff tears and to evaluate implant survival, shoulder function, and patient satisfaction. We prospectively analyzed patients with rotator cuff tears deemed irreparable on preoperative magnetic resonance imaging for whom nonoperative therapy was unsuccessful and who underwent balloon placement from 2014 to 2017 with minimum 1-year follow-up. Shoulder function was assessed using the CM score and the 12-Item Short Form Health Survey. The study included 51 patients (22 women and 29 men) with a mean age at surgery of 63 years (range, 50-78 years). The mean follow-up period was 36 months (range, 24-56 months). The postoperative acromiohumeral interval and total preoperative CM score predicted the postoperative CM score at final follow-up. The implant survival rates were 92% at 6 and 12 months, 90% at 2 years, and 87% at 3 and 4 years. Five patients underwent reverse total shoulder arthroplasty, and 1 underwent latissimus dorsi tendon transfer. Postoperatively, mean CM scores (± standard deviation) improved for range of motion (from 11 ± 5.4 to 34 ± 6.8) and strength (from 13± 5.4 to 28 ± 12) (P < .01 for both). The total CM score improved from 27 ± 7.4 preoperatively to 77 ± 15 postoperatively (P < .01). The physical and mental component summary scores on the 12-Item Short Form Health Survey improved from 27 ± 5.0 to 51 ± 6.5 (P= .02) and from 44 ± 15 to 56 ± 8.0, respectively (P < .01). Thirty-eight patients reported excellent satisfaction, 8 were satisfied, and 5 were dissatisfied. Of the patients, 50 (98%) exceeded the minimal clinically important difference (≥10.4) and patient acceptable symptom state (≥44). At mean 3-year follow-up, subacromial balloon spacer placement for massive, irreparable rotator cuff tears was associated with a significant improvement in shoulder function, limited need for revision surgery, and high patient satisfaction. A greater postoperative acromiohumeral interval and lower preoperative CM score predicted a lower postoperative CM score at final follow-up. Level IV, retrospective cohort study and treatment study.

Augmentation of Internal Fixation With Multiplanar External Fixator in High Risk Hind Foot Fusion Patients

Category:Hindfoot; Ankle; DiabetesIntroduction/Purpose:Achieving adequate fixation is a critical component for successful fusion. Internal fixation can be compromised in the setting of poor bone quality due to open trauma, infection, osteoporosis, neuropathic arthropathy resulting in published ankle non-union rates of 38% in high risk patients. These failures may be magnified by weightbearing non-compliance.While the use of multiplanar external fixation (MEF) alone can be utilized - it can often require an extended period of time within the frame (mean 18 weeks, range 9-28 weeks) and complications such as pin site infections. We hypothesized that hybrid fixation, MEF in conjunction with internal fixation, will provide adequate stability elevating the fusion rates in complex fusion cases while allowing early weight bearing and reduces the MEF time and infection rate.Methods:Eleven patients were identified that demonstrate significant risk factors for a successful fusion (infection, charcot, neuropathy, smoking, history of non-union) that were treated with internal fixation augmented with MEF. Patients with an active infection underwent surgical irrigation and debridement, placement of an antibiotic spacer and a course of intravenous antibiotics six weeks prior to placement of internal fixation. In these cases, MEF was placed at the time of surgical irrigation and debridement to allow for stability. In those patient’s without an active fixation, both the internal fixation and MEF were placed at the same time. Internal fixation construct was based on surgeon preference. Patients were allowed to transfer weight bear at the time of surgery and could advance as tolerated after 2 weeks. CT was utilized to assess fusion. Outcomes measured were fusion rate and occurrence of internal fixation infection.Results:The mean age of patients was 55 (range 26-75), eight patients had diabetes, three were current smokers, two were former smokers, two patients had open trauma, one patient had peripheral neuropathy and one patient had a history of a non- union with known non-compliance. Six patients had an active infection and underwent irrigation and debridement, placement of antibiotic spacer and MEF during antibiotic treatment. Seven patients underwent intramedullary nail fixation, three patients underwent plate and screw constructs and one patient underwent screw only fixation. CT demonstrated fusion in all patients (100%). The mean time for external fixation was 72 days (range 41-111). There were no cases of infected internal fixation.Conclusion:The findings of the current study suggest high rates of hind foot fusion with the use of internal fixation augmented with MEF in a complex patient group with identified high non-union risk factors. Using internal fixation, patients time in the frame is much reduced than published studies evaluating MEF alone for fusion fixation. MEF did not result in any cases of infected internal fixation. Patients with hybrid fixation also benefit from early weight bearing. We emphasize the importance of good surgical technique and infection management using this technique.

Short Term Outcome of Laparoscopic Trans-Abdominal Preperitoneal (TAPP) Inguinal Hernia Repair Without Mesh Fixation, a Comparative Study

Background: Laparoscopic repair of groin hernia is gaining popularity, most surgeons follow up the consensus of mesh fixation especially by tissue penetrating methods, as mesh fixation helps prevent recurrence it also, may cause nerve injuries leading to acute and/or chronic postoperative pain, many alternatives for mesh fixation do exists as use of self-gripping mesh, use of absorbable tacks, use of fibrin glue and the mesh placement in the extra-peritoneal space without fixation as we tried to investigate in this study. Patient and method: 46 patients undergoing laparoscopic trans-abdominal preperitoneal repair of groin hernia were randomly allocated into two equal groups, A (group of mesh fixation with absorbable tacks) and B (group of mesh no fixation). Preoperative, operative, and postoperative data in both groups, namely recurrence rate, acute and chronic pain, and local complications were statistically analyzed in comparison to each other. Results: Throughout the analysis of the data there were no statistically significant differences between both groups regarding demographic data, hernia side, and hernia type. the operative time, acute pain score, and incidence of chronic pain were longer in the fixation group without statistical significance, we recorded one case of recurrence in the non-fixation group but without statistical significance. Conclusion: Mesh placement in the preperitoneal space during laparoscopic trans-abdominal pre-peritoneal repair of inguinal hernia is a safe efficient method as it is not associated with increased recurrence rate or postoperative pain.

Short Term Outcome of Laparoscopic Trans-Abdominal Preperitoneal (TAPP) Inguinal Hernia Repair Without Mesh Fixation, a Comparative Study

Background: Laparoscopic repair of groin hernia is gaining popularity, most surgeons follow up the consensus of mesh fixation especially by tissue penetrating methods, as mesh fixation helps prevent recurrence it also, may cause nerve injuries leading to acute and/or chronic postoperative pain, many alternatives for mesh fixation do exists as use of self-gripping mesh, use of absorbable tacks, use of fibrin glue and the mesh placement in the extra-peritoneal space without fixation as we tried to investigate in this study. Patient and method: 46 patients undergoing laparoscopic trans-abdominal preperitoneal repair of groin hernia were randomly allocated into two equal groups, A (group of mesh fixation with absorbable tacks) and B (group of mesh no fixation). Preoperative, operative, and postoperative data in both groups, namely recurrence rate, acute and chronic pain, and local complications were statistically analyzed in comparison to each other. Results: Throughout the analysis of the data there were no statistically significant differences between both groups regarding demographic data, hernia side, and hernia type. the operative time, acute pain score, and incidence of chronic pain were longer in the fixation group without statistical significance, we recorded one case of recurrence in the non-fixation group but without statistical significance. Conclusion: Mesh placement in the preperitoneal space during laparoscopic trans-abdominal pre-peritoneal repair of inguinal hernia is a safe efficient method as it is not associated with increased recurrence rate or postoperative pain.

Safety Profile of Artelon Use for Soft Tissue Reconstruction in Foot and Ankle Surgery

Category:Basic Sciences/Biologics; Ankle; Hindfoot; Midfoot/Forefoot; SportsIntroduction/Purpose:Artelon is a synthetic degradable polyurethaneurea graft which has been investigated and utilized for soft tissue reconstruction in a variety of orthopaedic settings. However, in the field of foot and ankle surgery, there is very limited reported clinical data on outcomes of surgery utilizing Artelon. The goal of this study was look at outcomes of foot and ankle surgery in which Artelon is used, including post-op VAS scores and complications including adverse foreign body reaction, infection, repeat surgery, and implant failure. Our hypothesis was that soft tissue reconstruction procedures utilizing artelon will have a low complication rate, similar to established complication rates for other soft tissue reconstruction procedures such as those utilizing allograft, autograft, or other synthetic tissue.Methods:The treating surgeon’s first 55 consecutive patients 18 years and older who were treated with artelon graft as part of a foot and ankle surgery are being included in this IRB-approved study. Through retrospective chart review, outcome measures including the procedure for which artelon was utilized, pre and post-op Visual Analogue Scale (VAS) scores, and complications including repeat surgery for graft failure, foreign body reaction, wound healing issues, infection, and osteolysis were assessed.Statistical analysis was done utilizing Student’s t-test for continuous variables and chi square test for categorical variables.Results:Average follow-up time was 246.5 days. The majority of patients had artelon placed for spring ligament reconstruction, brostrom procedures, or achilles tendon reconstruction. VAS scores dropped significantly from before surgery to 3 weeks post- operatively (5.6 to 3.2, p<0.05). VAS scores stabilized after 3 weeks, with final follow-up score at 2.9. There were no reports of osteolysis in the area of the graft placement, adverse foreign body reaction, or episodes of graft failure. There were two major complications involving artelon surgical sites: one patient required a free flap for wound coverage, and another required an operative debridement with hardware and artelon removal, antibiotic spacer placement, and subsequent hindfoot fusion. Other minor complications not requiring operative intervention included cellulitis (3 patients) and delayed wound healing (5).Conclusion:Artelon is a safe and effective implant that can be utilized for soft tissue reconstruction in the foot and ankle, with similar post-operative pain recovery and wound complication rates compared to established historical data for these procedures. Additional studies must be done looking at long-term patient outcomes with utilization of artelon, and direct comparative studies with other soft tissue reconstruction techniques and materials in the foot and ankle.

P136. Clinical and radiographic outcomes after lumber decompression with placement of interlaminar spacers versus decompression alone

BACKGROUND CONTEXT Lumbar decompression is a viable treatment option for spinal stenosis with neurogenic claudication that has failed conservative treatment. However, given the relatively high rates of reoperation with decompression alone (up to 23%) and the increased surgical burden associated with fusion, alternative stabilization techniques such as dynamic interlaminar spacers have been utilized with the goal of providing stabilization while also preserving motion and native biomechanics. PURPOSE The purpose of this study is to evaluate whether interlaminar spacers can effectively augment lumbar decompression in the treatment of symptomatic spinal stenosis. STUDY DESIGN/SETTING Retrospective cohort study at a single institution. PATIENT SAMPLE Ninety-seven patients were included for analysis. Forty-three of these patients underwent lumbar decompression with placement of an interlaminar spacer, and 54 underwent lumbar decompression alone. OUTCOME MEASURES Radiographic parameters: anterior disc height, posterior disc height, segmental alignment, lumbar lordosis, lumbar range of motion, and foraminal height were measured before and after surgery. Outcome measures such as complication rates, and reoperation rates were also compared between the two cohorts. METHODS This is a retrospective cohort study at a single institution between January 2013 and November 2016. Ninety-seven patients were included for analysis. Forty-three of these patients underwent lumbar decompression with placement of an interlaminar spacer, and 54 underwent lumbar decompression alone. Radiographic parameters such as anterior disc height, posterior disc height, segmental alignment, lumbar lordosis, lumbar range of motion, and foraminal height were measured before and after surgery. Outcome measures, complication rates, and reoperation rates were also compared between the two cohorts. RESULTS Patients in the interlaminar spacer cohort had a significant increase in mean posterior disc height (4.5 to 5.1, p = 0.04) and decrease in mean anterior disc height (9.2 to 8.5 mm, p = 0.02). No significant anterior or posterior disc height change occurred in the laminectomy alone cohort. Both groups had a statistically significant decrease in segmental lumbar lordosis, although there was no observed difference in this degree of change between the two groups and no change in overall lumbar lordosis from L1-S1 in either cohort. Both cohorts demonstrated significant improvement in both Visual Analog Scores (VAS) and Oswestry Disability Index (ODI) postoperatively. The two cohorts had similar rates of postoperative complications, and the interlaminar spacer group had a slightly lower rate of reoperation (11.6% vs 20.4%, p = 0.28). CONCLUSIONS These results indicate that lumbar decompression supplemented with interlaminar spacers can lead to substantial improvement in both clinical and radiographic outcomes. We also found that the interlaminar spacer cohort had similar rates of complications and a lower reoperation rate, which deviates from previously published studies that demonstrate a substantially higher complication rate with interlaminar spacers. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Rectilinear Tasks Optimization of a Modular Serial Metamorphic Manipulator

Abstract This paper proposes a method for optimizing rectilinear tasks on a 3 degrees-of-freedom (DoF) modular serial metamorphic manipulator. The overall experimental process was designed in order for theoretical assumptions and previous experimental results, regarding the characteristics of a class of reconfigurable manipulators to be verified. The optimization procedure undergoes two stages. In each stage, the tasks are initially simulated and the optimal solutions obtained are afterward evaluated in the manipulator. Optimal task placement in the configuration space of the reference anatomy is concerned in the first optimization stage. Two different kinematic manipulability measures are utilized to form the objective function of the genetic algorithm (GA) used. Determination of the optimal anatomy for each task execution is concerned in the second stage. All feasible anatomies are exhaustively evaluated, and the anatomy with minimum execution time achieved in simulation is considered as optimal. The simulated tasks are executed for the reference and the optimal anatomy extracted. Overall task execution time reduction is measured. For tasks executed, Tool Center Point (TCP) position and velocity are obtained from navigation equations using measurements from an inertial measurement unit (IMU) sensor. In order to obtain more accurate solutions from position and velocity equations, a Kalman filter (KF) algorithm is implemented. Finally, conclusions are made based on the results of each task execution. Overall the metamorphic manipulator can achieve higher kinematic performance and minimize task execution time for the optimal anatomy calculated. Optimal task placement for the reference anatomy also reduces the task execution time.

Intrathecal Access Through Suboccipital Port in Patients With Spinal Muscular Atrophy and Complex Spines: Case Series and Technical Note.

IntroductionMany patients with the spinal muscular atrophy (SMA) have complex spinal anatomy, secondary to thoraco-lumbar spinal fusions. Their fragile musculoskeletal anatomy potentiates limb and joint injury if conventional spinal fluid access modalities are utilized. This creates a challenge when attempting to deliver intrathecal medications such as nusinersen (Spinraza®). Catheter placement in the cervical subarachnoid space with a caudally directed tip is potentially beneficial. This article describes our experience with Spinraza injections into the thecal space through a suboccipital port. This allowed for simple, chronic, and reliable cerebrospinal fluid (CSF) aspiration and intrathecal injections.MethodsA total of 15 patients with SMA and complex spinal anatomy were implanted with a cervical subarachnoid catheter, connected to a suboccipital access port. We retrospectively reviewed the charts of these patients for clinical outcomes and complications. All patients then underwent serial port cannulation, aspiration of CSF, and injection of Spinraza following standard manufacturer dosage guidelines.ResultsThe age range was 3 to 49. Two had type-1 SMA, 10 had type-2 SMA, and three had type-3 SMA. We were able to successfully cannulate the port, aspirate CSF, and inject Spinraza during all access attempts. Two incidents of subcutaneous CSF leaks were resolved through reoperation and one incident of transient CSF leak was resolved without surgical repair.ConclusionPatients with SMA requiring intrathecal injections of Spinraza can be treated safely and efficiently with this novel implantation technique. The complication rates are low and the injection time is dramatically lower than with conventional injection techniques.

Characterizing Femoral and Acetabular Bone Loss in Two-Stage Revision Total Hip Arthroplasty for Infection

BackgroundThe process of infection and multiple procedure-related factors in 2-stage exchange arthroplasty may lead to severe bone loss that can complicate subsequent reimplantation. The primary purpose of this study is to quantitatively characterize the extent of bone loss on the femoral and acetabular side prior to reimplantation during 2-stage revision hip arthroplasty for infection. MethodsThis retrospective case series includes 47 patients with planned 2-stage exchange arthroplasty for treatment of infected total hip replacement. Demographic, clinical, and surgical information, and complications during the 2-stage process were collected on all patients. The radiographs of all patients were reviewed prior to first-stage explantation and post-reimplantation or latest follow-up to characterize bone loss using the Paprosky classification systems. ResultsOf the 47 patients with planned 2-stage exchange, 10 patients (21%) were not reimplanted. Following explant and spacer placement, 32 patients (68%) experienced progressive femoral bone loss, and 20 (43%) experienced progressive acetabular bone loss. Patients who experienced progression of both femoral and acetabular bone (14, 30%) had a longer time between resection and reimplantation (164 ± 128 vs 88 ± 26 days, P = .03). A reimplantation time of greater than 90 days was associated with an increased risk of combined bone loss progression (15% vs 53%, P = .01). For patients who underwent reimplantation (79%), increased bone loss led to high rates of diaphyseal femoral fixation (97%) and revision acetabular components (38%). ConclusionIncreased time to reimplantation in 2-stage exchange arthroplasty for prosthetic hip infections is associated with a high rate of acetabular and femoral bone loss, and increased complexity of reimplantation.

Subacromial Balloon Spacer Implantation.

Massive irreparable rotator cuff tears present a treatment challenge for the orthopedic surgeon. There is no gold standard among numerous treatment options including nonoperative management, partial repair, debridement, superior capsular reconstruction, and reverse shoulder arthroplasty. In recent years, yet another option, an implantable biodegradable subacromial balloon spacer has become available with promising early results. Biomechanical studies have demonstrated that the balloon spacer effectively restores the normal humeral head position and glenohumeral joint mechanics. This device has been used in Europe since 2012 with promising clinical results. Most of the studies on this implantable balloon represent single surgeon uncontrolled case series with small numbers of patients, but they report improvements in pain and function following spacer placement, with the longest term studies reporting maintenance of improvements for up to 5years. Certain studies have shown a benefit when the procedure is done in isolation as well as in combination with other arthroscopic procedures, such as partial rotator cuff repair. The balloon subacromial spacer is a promising new device that can be used in the treatment of patients with massive, irreparable rotator cuff tears. In our experience, patients without arthritis who have active forward elevation over 90 degrees and an intact subscapularis have the best chance of a good outcome. We recommend performing the procedure arthroscopically along with any other indicated procedures including debridement, partial repair, and biceps tenotomy or tenodesis. High-quality long-term studies are needed to better define the indications and outcomes of the implantable balloon spacer in the management of irreparable cuff tears.

Adding a Fibular Strut Allograft to Intramedullary Nail and Cancellous Autograft During Stage II of the Masquelet Technique for Segmental Femur Defects: A Technique Tip.

Reconstruction of segmental diaphyseal bone defects has been a major challenge in limb salvage surgery. Staged reconstruction as first described by Masquelet is a common strategy to deal with this problem in limb salvage surgery. One consequence of this technique is a time period of prolonged limited weightbearing while the segmental defect heals. The purpose of this study was to describe an adjunctive technique for stage II of the Masquelet procedure and retrospectively analyze the outcome and weight bearing progression of 3 patients who sustained femur fractures with significant bone loss and underwent this technique. A retrospective chart review was performed. The patients (2 males, 1 female with an average age of 36.6 years) all sustained segmental femur fractures which resulted in significant bone loss. Induced membrane technique with adjunct use of a fibular strut allograft was performed after initial stabilization and PMMA spacer placement. All three patients went on to union and full weight bearing after being treated by the described technique. All the patients were allowed toe-touch weight bearing immediately after surgery and all progressed to weight bearing as tolerated at an average of 3.6 months. Using a fibular strut allograft as an adjunct to the induced membrane technique serves as a biologic and mechanical scaffold and may allow earlier weightbearing.

A case of severe basilar invagination and AAD, corrected using the technique of DCER-distraction, compression, extension, reduction (with spacer + universal reducer).

The author has described his own technique of DCER (distraction, compression, extension, and reduction) to reduce and realign the deformity and relieve spinal compression (indicated in congenital anomalies with occipitalized C1 arch). In addition, he developed special C1–2 spacers and a universal reducer. Here, a 30-year-old male with severe BI (20 mm, above the clivus) with AAD underwent the technique of spacer placement (distraction) followed by cable reduction (leading to compression and extension at the occiput–C1–C2 region). Another short example is presented where an 8-year-old boy (severe BI, AAD with posterior fossa dermoid) underwent additional correction—C2 forward translation and excision of the dermoid.The video can be found here: https://youtu.be/XIMpkYjxgRk