Sleep disruption and sleep position: Increased wake frequency in supine predicts lateral position preference.

Little is known about the physiological and biomechanical factors that determine individual preferences in lying posture during sleep. This study investigated relationships between position preference and position-specific arousals, awakenings, limb movements and limb movement arousals to explore the mechanisms by which biomechanical factors influence position preference. Forty-one mature-aged adults underwent 2 nights of at-home polysomnography ~2 weeks apart, on a standardised firm foam mattress, measuring nocturnal sleep architecture and position. The lateral supine ratio and restlessness indices specific to lateral and supine positions including limb movement index, limb movement arousal index, arousal index, wake index, respiratory arousal index and apnea-hypopnea index were calculated and analysed via linear mixed-effects regression. In the supine position, all restlessness indices were significantly increased compared with the lateral position, including a 379% increase in respiratory arousals (ß = 7.0, p < 0.001), 108% increase in arousal index (ß = 10.3, p < 0.001) and 107% increase in wake index (ß = 2.5, p < 0.001). Wake index in the supine position increased significantly with more lateral sleep (ß = 1.9, p = 0.0013), and significant correlation between lateral supine ratio polysomnography 1 and lateral supine ratio polysomnography 2 (ß = 0.95, p < 0.001) indicated strong consistency in sleep preference. Overall, the findings suggest that some individuals have low tolerance to supine posture, represented by a comparatively high wake index in the supine position, and that these individuals compensate by sleeping a greater proportion in the lateral position.

Accuracy of oscillometric noninvasive blood pressure at the ankle in the lateral position during general anesthesia.

BACKGROUND: This study aimed to evaluate the accuracy of ankle blood pressure measurements in relation to invasive blood pressure in the lateral position. METHODS: This prospective observational study included adult patients scheduled for elective non-cardiac surgery under general anesthesia in the lateral position. Paired radial artery invasive and ankle noninvasive blood pressure readings were recorded in the lateral position using GE Carescape B650 monitor. The primary outcome was the ability of ankle mean arterial pressure (MAP) to detect hypotension (MAP < 70 mmHg) using area under the receiver operating characteristic curve (AUC) analysis. The secondary outcomes were the ability of ankle systolic blood pressure (SBP) to detect hypertension (SBP > 140 mmHg) as well as bias (invasive measurement - noninvasive measurement), and agreement between the two methods using the Bland-Altman analysis. RESULTS: We analyzed 415 paired readings from 30 patients. The AUC (95% confidence interval [CI]) of ankle MAP for detecting hypotension was 0.88 (0.83-0.93). An ankle MAP of ≤ 86 mmHg had negative and positive predictive values (95% CI) of 99 (97-100)% and 21 (15-29)%, respectively, for detecting hypotension. The AUC (95% CI) of ankle SBP to detect hypertension was 0.83 (0.79-0.86) with negative and positive predictive values (95% CI) of 95 (92-97)% and 36 (26-46)%, respectively, at a cutoff value of > 144 mmHg. The mean bias between the two methods was - 12 ± 17, 3 ± 12, and - 1 ± 11 mmHg for the SBP, diastolic blood pressure, and MAP, respectively. CONCLUSION: In patients under general anesthesia in the lateral position, ankle blood pressure measurements are not interchangeable with the corresponding invasive measurements. However, an ankle MAP > 86 mmHg can exclude hypotension with 99% accuracy, and an ankle SBP < 144 mmHg can exclude hypertension with 95% accuracy.

Intramedullary nailing of humeral shaft fractures: percutaneous nailing in the lateral position through the Neviaser approach is a reliable technique.

BACKGROUND: Displaced humeral shaft fractures are frequently treated by osteosynthesis in the active patient. We aimed to evaluate the results of intramedullary nailing (IMN) in the lateral position with the Neviaser approach and to compare them with those from IMN nailing in the standard position and conventional approach. METHODS: In the retrospectively evaluated, single-center study, we compared 20 cases of long IMN for fractures of the proximal or middle third of the humerus shaft (Multilock; Synthes Laboratory) in the lateral position with the percutaneous Neviaser approach with 52 cases of IMN in the standard position. The mean age of patients was 62 ± 21 years. Clinical outcomes were analyzed: Constant score, subjective shoulder evaluation score and range of motion. Radiographically, entry point at the proximal part of the humerus, the healing rate and the possible association between the critical shoulder angle (CSA) and the correct positioning of the nail were assessed. RESULTS: With a mean follow-up of 26 ± 2 months, the healing rate was 89% (64/72) in the overall series, (eight patients in non-union), with no difference between the two groups. The overall mean active anterior elevation (AAE) was 125 ± 22°, mean external rotation (ER1) was 35 ± 17°, and mean internal rotation (IR) was at L3. The mean Constant score was 58 ± 23 and subjective shoulder evaluation score 73 ± 12%. ranges of motion were better in the lateral than standard position group (AAE 133 ± 17 vs. 122 ± 23, P = .03; ER1 47 ± 13 vs. 30 ± 16, P < .001; IR T12 vs. L5, P = .02). The nail was less often protruding in the lateral than standard position group (1/20 [5%] vs. 20/52 [38.5%], P = .002). The nail was better positioned from the anteroposterior view (nail centered: 16/20 [75%] vs. 26/52 [50%], P = .047) and lateral view (nail centered: 18/20 [90%] vs. 34/52 [65.4%], P = .02) in the lateral than standard position group. We found no association between nail position, type of approach and CSA. CONCLUSIONS: In the short-term follow-up, osteosynthesis of humeral shaft fractures by using long IMN in the lateral position with the Neviaser approach is a reliable technique. The positioning of the nail, in particular its entry point, and the clinical results were better with the lateral position and Neviaser approach than with the standard position and conventional approach. Further studies with a larger number of patients, assessment of the learning curve, and analysis of the impact of this technique on comorbidities (unchanged cerebral perfusion) are needed to fully validate this technique.

Fetuses with deceleration of growth improve their growth following maternal rest.

OBJECTIVE: The purpose of this study was to determine if fetuses with deceleration of growth velocity resulting in an EFW <10th percentile increase their growth above the 10th percentile following 2 weeks of maternal rest in the left lateral recumbent position. METHODS: This was a retrospective observational study of 265 fetuses with the prenatal diagnosis of an EFW <10th percentile. Fetuses were classified by four definitions of abnormal growth velocity: (1) a growth velocity less than 20 g/day, (2) 30 percentile decrease in the EFW, (3) 50 percentile decrease in the EFW, and (4) abnormal growth trajectory. Once the fetuses were identified with an EFW <10th percentile the patient was requested to begin 2 weeks of rest in the left lateral recumbent position during her waking hours following which the EFW was reassessed 2 week later to determine the effect of maternal rest on the EFW. RESULTS: Irrespective of the four types of decreased growth velocity described in the methods section, there was as significant increase (p < 0.001) in the EFW following 2 weeks of maternal rest as follows: (1) growth less than 20 g/day (75%); (2) decrease of 30 or more EFW percentiles (79%); (3) decrease of 50 or more EFW percentiles (64%); and abnormal growth trajectory (77%). CONCLUSIONS: This suggests an important role of increased maternal cardiac output as the result of resting in the left lateral recumbent position that may be associated with improved fetal growth. These observations should be the basis for future prospective randomized trials to test this hypothesis.

The role of patient positioning in surgical fixation of the calcaneus fractures using the lateral extensile approach.

INTRODUCTION: Calcaneus is the most commonly fractured tarsal bone. Open reduction and internal fixation of the displaced intra-articular fractures is considered the gold standard treatment. The lateral extensile approach is the most commonly used approach, and usually, the patients are kept in lateral decubitus position. Recent study has descried calcaneus fracture fixation utilizing the lateral extensile approach with the patient in prone position. The aim of this study was to compare the postoperative radiological outcome, reoperation rate, operative and anesthesia time, infection and the wound complications rate between the two groups. METHODS: The data of 49 adult patients with unilateral closed calcaneus fracture underwent open reduction and internal fixation using lateral extensile approach were collected. Postoperative Bohler's, Gissane angles and complications rate were compared between the two groups. RESULTS: A total of 49 patients were included. Lateral position was utilized in 26 patients (53.1%), while 23 patients (46.9%) were operated in prone position. Majority of the patients were males 87.8% (43 patients), and the mean age of the patients was 31.12 ± 7.50. The most commonly mechanism of injury was fall from height in (91.8%) of the patients. The mean preoperative Bohler's angle was 9.33 ± 13.07 and increased to 22.69 ± 9.15 postoperatively. The mean preoperative angle of Gissane was 130.45 ± 26.98 whereas it was 124.76 ± 17.20 postoperatively. The mean postoperative Bohler's angle and angle of Gissane were significantly higher among patient who underwent fixation in lateral position (25.88 ± 6.62, 137.15 ± 11.17) when compared to the prone one (19.09 ± 10.35, 110.74 ± 10.81). There was no significant difference between the two groups regarding the reoperation rate (p 0.947), infection (p 0.659, operative time (p 0.688), anesthesia time (p 0.522) and wound complications (p 0.773). CONCLUSION: Surgical restoration of the Bohler's and Gissane's angles with the patient placed in the lateral decubitus position remains superior to the prone position with no difference in the complication rate between the two groups.

Effects of Right Lateral Position on Changes of Fetal Hemodynamics in Late Pregnancy.

OBJECTIVE: We aim to evaluate the effect of right lateral position on fetal hemodynamics (including umbilical artery [UA] and middle cerebral artery (MCA) blood flow-velocity waveform). METHODS: In total, 150 low-risk singleton full-term pregnant women were included in the study from November 2021 to January 2022. Doppler flow velocity waveforms of the fetal UA and MCA tested by ultrasound were collected in gestation of 37-40 weeks. Computational analysis was performed using the one-way ANOVA test. RESULTS: Compared with the maternal left lateral position, there was a significant increase in Doppler indices of UA-RI (P = .033), UA-S/D (P = .019) and MCA-PSV (P = .021) and a significant decrease in MCA-RI (P = .030) in the supine position group. There was no statistical significance in all Doppler indices between the left and right lateral position (P > .05). Among the Doppler indices of three different maternal positions, there was no significance in both UA-PI and MCA-PI (P > .05). CONCLUSION: There were no significant differences on changes of the fetal hemodynamics between left and right lateral positions. Pregnant women could adopt to lie in the left or right lateral position alternately to relieve the discomfort in late pregnancy.

Sensitivity Enhancement of 2D Material-Based Surface Plasmon Resonance Sensor with an Al-Ni Bimetallic Structure.

In this paper, a variety of 2D materials on the surface plasmon resonance sensor based on Al-Ni bimetallic layer are compared. Simulation results indicate that lateral position shift, which is calculated according to the real and imaginary parts of the refractive index of material, can be used as an effective parameter to optimize the sensitivity. By using the parameters for optimizing the SPR structures, the results show that the multiple layer models of Al(40 nm)-Ni(22 nm)-black phosphorus (BP)(1 L) and Al(40 nm)-Ni(22 nm)-blue phosphorus (BlueP)/WS2(1 L) exhibit average angular sensitivities of 507.0 °/RIU and 466 °/RIU in the refractive index range of 1.330-1.335, and maximum sensitivity of 542 °/RIU and 489 °/RIU at the refractive index of 1.333, respectively. We expect more applications can be explored based on the highly sensitive SPR sensor in different fields of optical sensing.

Antegrade femoral nailing in the lateral decubitus position: a case series, technical tips and review of literature.

BACKGROUND: Femoral intramedullary nailing is traditionally performed with the patient supine on a fracture table. We aimed to describe a case series of femoral intramedullary nailing for fracture in the lateral position, with discussion of the operative technique. METHODS: A retrospective analysis identified 52 patients who underwent femoral intramedullary nailing performed in a lateral position without traction over a 5-year period at a single level 1 trauma center. Medical records were reviewed for demographics, blood loss including need for transfusion, operative duration, complications, length of stay, fracture union, re-operation and death. RESULTS: There were 24 subtrochanteric, 16 peri-trochanteric and 12 diaphyseal femoral fractures. Mean operative time was 136.2 ± 101.4 min with a mean estimated blood loss of 372.5 ± 349.6 ml. Seventeen patients required blood transfusion. Mean length of stay was 10.3 ± 8.1 days. There were 3 (5.8%) surgical (compartment syndrome, infection and retained drain) and 12 (23.1%) medical complications, with a 30-day mortality rate of 3.8% (2). Mean follow-up was 9.9 ± 8.7 months. The union rate was 94.2% (49) and 3.8% (2) patients required revision fixation (hardware exchange for irritation and exchange nailing for non-union). Discharge destination was home, rehabilitation center and specialized nursing facility in 21 (40.4%), 16 (30.8%) and 15 (28.8%) patients, respectively. DISCUSSION AND CONCLUSION: Femoral intramedullary nailing in the lateral decubitus position is a useful technique of managing peri-trochanteric, subtrochanteric and diaphyseal femoral fractures. We describe a known technique with technical tips, which has distinct advantages over traditional supine positioning especially in certain patient and fracture types. In addition, operative times, blood loss, length of stay, revision and outcomes were comparable to the literature.

Effect of different surgical positions on intraocular pressure: a cross-sectional study.

BACKGROUND: Intraoperative intraocular pressure (IOP) elevation is a risk factor for postoperative blindness. Surgical position is associated with intraoperative IOP elevation. In China, there are few studies on the effect of various surgical positions on intraoperative IOP. This study was conducted to explore IOP change and its related factors in four common surgical positions in China. METHODS: This was a cross-sectional observational study. A total of 325 surgical patients who had non-ocular surgery from January 2019 to December 2019 in the hospital, were enrolled in this study. During their surgeries for general anesthesia, these participants were placed in lithotomy position/lateral position/prone position/supine position according to their surgery requirement. IOP was measured by icareTA03 handheld portable tonometer at 9 different time points from admission to exiting the operation room. And general information, postural position, and surgery information were collected through a uniform questionnaire. Multivariate analysis was performed to explore the related factors of IOP change. RESULTS: IOP of both eyes on lithotomy position, lateral position, and supine position showed statistical differences by ANOVA test at each time point (p < 0.05). IOP of both eyes in the prone position before exit from the operating room was significantly higher than IOP 10-min after anesthesia (p < 0.01). IOP under different postural angles showed statistical differences (F value = 4.85, P < 0.05), and the larger the head-down angle, the higher the IOP. IOP on the compressed side in the lateral position was higher than that on the non-compressed side (p < 0.01). In the multivariate linear regression analysis adjusted by other factors, postural position and baseline IOP were associated with IOP difference between before and after surgery (p < 0.01). CONCLUSION: IOP in the four surgical positions showed different change patterns with the surgical process and position change. Nurses should assist the surgeon to reduce the head-down angle without interfering with the surgical operation and strengthen the inspection of IOP on patients with long-time surgery, to avoid intraoperative rapid IOP changes.

Effect of sigh in lateral position on postoperative atelectasis in adults assessed by lung ultrasound: a randomized, controlled trial.

BACKGROUND: Postoperative atelectasis occurs in 90% of patients receiving general anesthesia. Recruitment maneuvers (RMs) are not always effective and frequently associated with barotrauma and hemodynamic instability. It is reported that many natural physiological behaviors interrupted under general anesthesia could prevent atelectasis and restore lung aeration. This study aimed to find out whether a combined physiological recruitment maneuver (CPRM), sigh in lateral position, could reduce postoperative atelectasis using lung ultrasound (LUS). METHODS: We conducted a prospective, randomized, controlled trial in adults with open abdominal surgery under general anesthesia lasting for 2 h or longer. Subjects were randomly allocated to either control group (C-group) or CPRM-group and received volume-controlled ventilation with the same ventilator settings. Patients in CPRM group was ventilated in sequential lateral position, with the addition of periodic sighs to recruit the lung. LUS scores, dynamic compliance (Cdyn), the partial pressure of arterial oxygen (PaO2) and fraction of inspired oxygen (FiO2) ratio (PaO2/FiO2), and other explanatory variables were acquired from each patient before and after recruitment. RESULTS: Seventy patients were included in the analysis. Before recruitment, there was no significant difference in LUS scores, Cdyn and PaO2/FiO2 between CPRM-group and C-group. After recruitment, LUS scores in CPRM-group decreased significantly compared with C-group (6.00 [5.00, 7.00] vs. 8.00 [7.00, 9.00], p = 4.463e-11 < 0.05), while PaO2/FiO2 and Cdyn in CPRM-group increased significantly compared with C-group respectively (377.92 (93.73) vs. 309.19 (92.98), p = 0.008 < 0.05, and 52.00 [47.00, 60.00] vs. 47.70 [41.00, 59.50], p = 6.325e-07 < 0.05). No hemodynamic instability, detectable barotrauma or position-related complications were encountered. CONCLUSIONS: Sigh in lateral position can effectively reduce postoperative atelectasis even without causing severe side effects. Further large-scale studies are necessary to evaluate it's long-term effects on pulmonary complications and hospital length of stay. TRIAL REGISTRATION: ChiCTR1900024379 . Registered 8 July 2019,.

Cephalic version by postural management in the lateral position without the knee-chest position for primiparous breech presentation: A retrospective cohort study.

AIM: This study aimed to determine the efficacy of postural management in the lateral position for primiparous breech presentation. METHODS: A retrospective cohort study was conducted at a single institution from January 2020 through December 2020. Participants were singleton primiparous pregnant women diagnosed with breech presentation between 28 + 0 and 29 + 6 weeks of gestation. The exclusion criteria were scheduled cesarean delivery, uterine malformation, transverse position, and scheduled delivery at another hospital. A doctor instructed the women in the intervention group to lie on their right sides several times a day if the fetal back was on the left side or lie on their left sides if the fetal back was on the right side. The knee-chest position and other methods were not recommended. The control group received expectant management care. The primary endpoint was the percentage of fetuses in a cephalic presentation 2 weeks later. RESULTS: Of the 56 women included in the study, 17 women were instructed to lie in the lateral position, and 39 women received expectant management care only. After 2 weeks, women who were instructed to lie in lateral position had a higher rate of fetal cephalic version than the control group (82.4% [14/17] vs. 43.6% [17/39], p = 0.017). No study participants experienced adverse effects. CONCLUSIONS: Two weeks of postural management in the lateral position without the knee-chest position significantly reduced the rate of primiparous breech presentation in the third trimester of pregnancy.

Combined anteroposterior approaches in lateral position treatment of lumbosacral tuberculous in single-stage.

BACKGROUND: The local anatomy of the lumbosacral region of spine is complicated, with special biomechanical characteristics. For surgical management of tuberculous spondylitis reported in the literature, the methods would be two-stage anterior and posterior approaches or one-stage anterior and posterior approach with patient's intraoperative position being changed. These types of surgery approaches would result in long operative duration and more intraoperative blood loss, and most important there is no coordination between anterior and posterior procedures. METHODS: The purpose of this study was to introduce a new procedure called in the lateral position single -stage combined anteriorposterior approaches for treatment of lumbosacral tuberculous spondylitis and to evaluate its preliminary surgical outcomes. Fifteen patients with lumbosacral tuberculous spondylitis who underwent single-stage anterior and posterior radical focal debridement and reconstruction in lateral position in our hospital from April 2005 to June 2012 were included in the study. There were 6 males and 9 females with the average age of 46.8 years. The tuberculous lesions involved the following regions: L3-4 in 5cases, L4-5 in 5 cases, L5-S1 in 2 cases, L4 in one case, and L5 in 2 cases. The assessment of surgical outcomes was conducted with clinical symptoms and radiological findings,including operative time, blood loss. deformity angle, Frankel grade and Kirkaldy-Willis evaluation. RESULTS: Operation posture: The right lateral position was used for 11 patients and the left lateral position was used for the remaining 4 patients. The average duration of operation for the 15 patients was 270 min. The average intraoperative blood loss was 1720 ml. The mean follow-up period was 4.2 years. There was no recurrence. The postoperative radiological findings showed that the interbody bone grafts were fixed without any dislodgment. There was significant difference between preoperative and postoperative lumbosacral lordotic angles. Kirkaldy-Willis classification rating for the 13 cases with satisfactory results. CONCLUSION: Single-stage combined anterior and posterior surgical management of lumbosacral tuberculous spondylitis with patient in lateral position can achieve radical focal debridement, anterior and posterior procedure coordination and spinal reconstruction.

Relationship between mattress internal air pressure and interface pressure distribution in the lateral position.

Previous research shows that maximum interface pressure increases when the patient is lying in the lateral position. However, it was unclear whether it was better to increase or decrease the internal air pressure to reduce the maximum interface pressure in the lateral position; thus, this study investigated this issue. In this study, we investigated the change in pressure redistribution because of the difference in internal air pressure between the supine and lateral positions on an active air mattress for pressure ulcer prevention management. Each participant's five internal air pressure values served as the independent variables. The interface pressure on the active air mattress was measured for 20 minutes. The sacral left iliac crest and left greater trochanteric interface pressures were measured using a portable pressure-measuring device. When seven of the 10 participants switched from the supine position to the left lateral position, there was a decrease in the maximum interface pressure as the internal air pressure increased. The maximum interface pressure in the greater trochanter in the lateral position was twice that in the sacral region in the supine position. These results show that increasing the internal air pressure in the lateral position might help reduce the maximum interface pressure.

Difference in tapered wedge stem alignment between supine and lateral position in cementless total hip arthroplasty via modified Watson-Jones anterolateral approach.

BACKGROUND: Whether different body positions during surgery affect postoperative stem alignment in total hip arthroplasty (THA) remains unclear. The purpose of this study was to clarify differences in tapered wedge stem alignment between supine and lateral positions in THA under the modified Watson-Jones anterolateral approach. METHODS: We reviewed 242 consecutive, primary cementless THAs performed with ceramic-on-cross-linked polyethylene via the modified Watson-Jones approach in either supine or lateral positions between 2009 and 2015 (supine group: 113 cases; lateral group: 129 cases). No specific reasons to select supine or lateral positions for the surgery were given during the study period. Computed tomography was performed pre- and postoperatively to measure preoperative femoral anteversion and postoperative stem anteversion, respectively. Stem alignment in coronal and sagittal planes was also evaluated. RESULTS: Mean difference in stem anteversion and femoral anteversion was 8.6 ± 9.4 in the supine position and 13.0 ± 11.4 in the lateral position (p = 0.0013). Although no significant difference was seen between groups for stem alignment in the coronal plane, flexed implantation was more likely in the supine group (46/113, 40.7%) than in the lateral group (20/129, 15.5%). A significant correlation was found between femoral anteversion and stem anteversion in both the supine and lateral groups (r = 0.68, p < 0.0001 and r = 0.52, p < 0.0001, respectively). CONCLUSION: Although stem anteversion was more strongly correlated with femoral anteversion in the supine position than in the lateral position, neutral position in the sagittal plane was more likely to be found with the lateral position than with the supine position. Surgeons can achieve ideal stem positioning by considering these results in the modified Watson-Jones approach in both the supine and lateral positions.

Lateral position: a friendly surgical position for intramedullary nailing of tibial shaft fractures via infrapatellar approach.

BACKGROUND: The conventional infrapatellar approach to intramedullary nailing of tibial fractures adopts the supine high-flexion knee position. However, this has disadvantages including difficulty in obtaining the proximal tibial anteroposterior view during intraoperative fluoroscopy, prolonged duration of fluoroscopy. Accordingly, the present study investigated the utility of the lateral position in the infrapatellar approach to intramedullary nailing of tibial shaft fractures. METHODS: The present study was a retrospective analysis of 112 patients who sustained closed tibial shaft fractures and treated with intramedullary nailing via the infrapatellar approach. Patients were divided into two groups according to surgical position: lateral or supine. The demographic and clinical data were collected and analyzed. RESULTS: There were 54 patients in the lateral and 58 in the supine position groups. The duration of surgery and fluoroscopy was shorter in the lateral group than the supine group (p < 0.05). Blood loss during surgery was lower in the lateral compared with supine position group (p < 0.05). The malunion rate was lower in the lateral position group as compared with the supine position group (p < 0.05); moreover, fewer surgical assistants were needed than in the supine group (p < 0.05). There were no significant differences in fracture healing time, other complications between the two groups (p > 0.05). CONCLUSIONS: The lateral position was a more convenient choice for intramedullary nailing of tibial shaft fractures via infrapatellar approach.

Comparing the Interface pressure distribution of the full body chest-lumbar cushion made of memory cotton with the traditional chest cushion.

BACKGROUND: Pressure injuries are common complications occurred duration hospitalization, whether the interface pressure distribution in full body memory cotton chest-lumbar cushion was superior than traditional chest cushion remains unclear. PURPOSE: This study aimed to compare the effects that the full body memory cotton chest-lumbar cushion versus traditional chest cushion on interface pressure. METHODS: A total of 66 healthy individuals were recruited. The volunteers were placed in the left lateral position and left armpit and iliac spine pressure and level of comfort were measured. Group differences were assessed using the paired t-test or Wilcoxon test according to data distribution. Additionally, multivariate regression analysis was applied to determine the potential role of sex, age, and body mass index on left armpit and iliac spine pressure and overall comfort. RESULTS: Compared with the traditional chest cushion, we noted that the full body chest-lumbar cushion made of memory cotton was associated with less pressure on the left armpit (38.17 ± 10.39 mmHg vs. 67.93 ± 14.67 mmHg, respectively; P < 0.0001) and iliac spine (43.32 ± 13.70 mmHg vs. 50.77 ± 20.94 mmHg, respectively; P = 0.0004). Moreover, we noted that the overall comfort with the memory cotton chest-lumbar cushion was higher than that with the traditional chest cushion (8.48 ± 1.08 vs. 6.36 ± 1.45, respectively; P < 0.0001). Finally, the multivariate regression analyses found iliac spine pressure could affect by sex (P = 0.0377) and body mass index (P = 0.0380). CONCLUSIONS: The full body chest-lumbar cushion made of memory cotton had beneficial effects on left armpit and iliac spine pressure and on comfort. These findings should be applied to future clinical practice.

Lateral lumbar interbody fusion after reduction using the percutaneous pedicle screw system in the lateral position for Meyerding grade II spondylolisthesis: a preliminary report of a new lumbar reconstruction strategy.

BACKGROUND: Utilization of a cage with a large footprint in lateral lumbar interbody fusion (LLIF) for the treatment of spondylolisthesis leads to a high fusion rate and neurological improvement owing to the indirect decompression effect and excellent alignment correction. However, if an interbody space is too narrow for insertion of an LLIF cage for cases of spondylolisthesis of Meyerding grade II or higher, LLIF cannot be used. Therefore, we developed a novel strategy, LLIF after reduction by the percutaneous pedicle screw (PPS) insertion system in the lateral position (LIFARL), for surgeons to perform accurate and safe LLIF with PPS in patients with such pathology. This study aimed to introduce the new surgical strategy and to present preliminary clinical and radiological results of patients with spondylolisthesis of Meyerding grade II. METHODS: Six consecutive patients (four men and two women; mean age, 72.7 years-old; mean follow-up period, 15.3 months) with L4 spondylolisthesis of Meyerding grade II were included. Regarding the surgical procedure, first, PPSs were inserted into the L4 and L5 vertebrae fluoroscopically, and both rods were placed in the lateral position. The L5 set screws were fixed tightly, and the L4 side of the rod was floated. Second, the L4 vertebra was reduced by fastening the L4 set screws so that they expanded the anteroposterior width of the interbody space. At that time, the L4 set screws were not fully tightened to the rods to prevent the endplate injury. Finally, the LLIF procedure was started. After inserting the cage, a compression force was added to the PPSs, and the L4 set screws were completely fastened. RESULTS: The mean operative time was 183 min, and the mean blood loss was 90.8 mL. All cages were positioned properly. Visual analog scale score and Oswestry disability index improved postoperatively. Bone union was observed using computed tomography 12 months after surgery. CONCLUSION: For cases with difficulty in LLIF cage insertion for Meyerding grade II spondylolisthesis due to the narrow anteroposterior width of interbody space, LIFARL is an option to achieve LLIF combined with posterior PPS accurately and safely. TRIAL REGISTRATION: UMIN-Clinical Trials Registry, UMIN000040268, Registered 29 April 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000045938.

Prevalence and characteristics of positional obstructive sleep apnea (POSA) in patients with severe OSA.

PURPOSE: We assessed the prevalence of positional patients (PPs) and the main predictors of positional dependency in severe obstructive sleep apnea (OSA). A simulated effect of positional therapy (PT) vs. continuous positive airway pressure (CPAP) was also assessed. METHODS: Polysomnographic recordings of 292 consecutive patients with severe OSA (Apnea-Hypopnea Index (AHI) ≥ 30) who slept > 4 h and had ≥ 30 min sleep in both supine and lateral positions were assessed. PPs were defined to have a supine AHI/lateral AHI ratio ≥ two and non-positional patients (NPPs) a supine AHI/lateral AHI ratio < two. RESULTS: A total of 35.3% of the severe OSA patients were PPs. They were less obese and had less severe OSA (p < 0.001) compared with NPPs. The percentage of total apnea-hypopnea time from total sleep time (AHT%) was the most significant predictor for positional dependency. By sleeping in the lateral posture (i.e. after simulated PT), 78 (75.7%) PPs obtained significant improvement of their OSA severity and 9 (8.7%) of them became "non-OSA". Moreover, if CPAP was used only for 50% of total sleep time, 53 patients (18.2%) gained more benefit from avoiding the supine posture than from CPAP therapy. CONCLUSIONS: More than a third of the studied severe OSA patients were PPs. These patients could achieve a significant decrease in the number and severity of apneas and hypopneas by adopting the lateral posture, suggesting that PT may be a valuable therapy for a significant portion of these severe OSA patients who for whatever reason are not being treated by CPAP. TRIAL REGISTRY: ClinicalTrials.gov Identifier: NCT03232658.

Influence of different PEEP levels on electrical impedance tomography findings in patients under general anesthesia ventilated in the lateral decubitus position.

To determine the effect of various PEEP levels on electrical impedance tomography (EIT) measured differences in regional ventilation, hemodynamics, lung mechanics and parameters of alveolar gas exchange. Thirty three patients scheduled for elective urologic surgery in general anesthesia in lateral decubitus position were randomized into three groups-PEEP 0, 5 and 10 mbar. EIT recording, arterial blood gas analysis and hemodynamic parameters were captured at three timepoints-before induction (T0), 5 min after lateral positioning (T1) and 90 min after positioning (T2). Dynamic compliance (Cdyn) was measured at T1 and T2. Offline EIT data analysis was performed to calculate EIT derived parameters of ventilation distribution. Patients ventilated with PEEP of 10 mbar had a significantly lower A-a (alveolo arterial) gradient over measurements and symmetrical distribution of ventilation measured by EIT. There was no significant difference in Cdyn, center of ventilation indices and inhomogeneity index between groups. There was no difference of mean arterial pressure, cardiac index and heart rate between groups. Patients with 5 mbar of PEEP had higher stroke volume index compared to 0 and 10 mbar at baseline and over measurements. Nondependent/dependent TV ratio as well as global inhomogeneity index were correlated with A-a gradient. Dynamic compliance showed no correlation to A-a gradient. In our study, a PEEP level of 10 mbar improved alveolar gas exchange without compromising hemodynamic stability in patients mechanically ventilated in the lateral decubitus position. EIT measured parameters may be used to determine optimal ventilation parameters in these patients with inhomogeneous lung mechanics. Further studies are needed in patients with various lung pathologies.

Total hip arthroplasty by direct anterior approach in the lateral position for the treatment of ankylosed hips.

OBJECTIVE: To investigate the clinical efficacy of total hip arthroplasty (THA) via the direct anterior approach (DAA) for the treatment of hip ankylosis in the lateral position. METHODS: A retrospective analysis was performed on the clinical data of 24 patients (39 hips) who underwent THA via the DAA in the lateral position for the treatment of hip ankylosis between January 2016 and December 2018. We performed bilateral THA for fifteen patients and unilateral THA for nine patients. Operation time, intraoperative blood loss, length of incisions, straight leg-raising time, length of postoperative hospital stay, operation-related complication, prosthesis position, radiological outcomes, postoperative pain relief (evaluated by VAS) and functional rehabilitation [evaluated by Harris hip score and range of motion (ROM)] were analyzed to determine clinical efficacy. These clinical data were compared and statistically analyzed with the clinical data of another 23 patients (28 hips) who underwent THA via the posterolateral approach (PLA) for the treatment of hip ankylosis in the lateral position. RESULTS: Follow-up was performed at 12-15 months. The incision length in the DAA group and the PLA group was (11.12 ± 1.69 vs. 14.36 ± 3.42) cm, the intraoperative blood loss was (371.25 ± 120.55 vs. 396.80 ± 101.21) ml, the operation time was (122.47 ± 25.40 vs. 138.47 ± 24.45) min, the postoperative hospital stay was (9.59 ± 4.62 vs. 12.08 ± 3.58) days, and the straight leg elevation time was (9.20 ± 2.12 vs. 12.34 ± 3.25) days, respectively. The prosthesis of the two groups was in a good position: The average angle of cup anteversion in the DAA group and the PLA group was (10.76 ± 2.84 vs. 15.36 ± 3.42)°, and the average angle of cup abduction in the DAA group and the PLA group was (40.00 ± 3.45 vs. 41.21 ± 2.85)° (P > 0.05). The VAS score, ROM and Harris score at different follow-up time points were significantly improved in the two groups compared with those before surgery. In the first 3 months after surgery, the VAS score, ROM and Harris score of the DAA group were significantly better than those of the PLA group (P < 0.05), but with the extension of the follow-up time, there was no significant difference in the above indicators between the two groups (P > 0.05). One case of greater trochanteric fracture occurred in the DAA group. Two cases of hip posterior dislocations occurred in the PLA group, and no dislocations occurred after manual closed reduction and hip fixation in bed for 1 month to the last follow-up. No complications such as infection, deep vein thrombosis, fat embolism, prosthesis loosening, limb length inequality or joint dislocation were reported. CONCLUSION: THA via the DAA for the treatment of hip ankylosis in the lateral position was safe and effective and had the advantage of reduced trauma, quicker recovery of hip function, lower incidence of postoperative dislocation and ability to expose the acetabulum fully and fit the prosthesis properly, providing satisfactory clinical efficacy.