Effect of wheelchair seating systems on scoliosis progression for children with neurological and neuromuscular disorders: a retrospective study of Custom-Contoured Wheelchair Seating and Modular Wheelchair Seating.

OBJECTIVES: To retrospectively evaluate the comparative effect of two wheelchair seating systems, Custom-Contoured Wheelchair Seating (CCS) and Modular Wheelchair Seating (MWS), on scoliosis progression in children with neuromuscular and neurological disorders and to determine any predictors for scoliosis progression. DESIGN: Longitudinal, retrospective cohort study SETTING: National Health Service regional posture and mobility service PARTICIPANTS: Non-ambulant paediatric wheelchair users with neuromuscular and neurological disorders (N = 75; 36 male, 39 female; mean age at seating intervention, 10.50 ± 3.97 years) issued CCS and MWS by the South Wales Posture and Mobility Service from 2012 to 2022. INTERVENTIONS: Two specialized wheelchair seating systems, CCS and MWS. MAIN OUTCOME MEASURES: A generalized least squares (GLS) model was used to estimate the effect of seat type on Cobb angle over time. RESULTS: Of the 75 participants enrolled, 51% had cerebral palsy. Fifty were issued CCS and 25 were issued MWS. Baseline Cobb angle was 32.9±18.9° for the MWS group and 48.0±31.0° for the CCS group. The GLS model demonstrated that time since seating intervention (χ2 = 122, p < .0001), seating type (χ2 = 52.5, p < .0001), and baseline scoliosis severity (χ2 = 41.6, p < .0001) were predictive of scoliosis progression. Condition was not a strong predictor (χ2 = 9.96, p = .0069), and sex (χ2 = 5.67, p = .13) and age at intervention (χ2 = 4.47, p = .35) were not predictive. Estimated contrasts of medical condition with seat type over time demonstrated smaller differences between MWS and CCS over time. Predicted scoliosis velocity was found to attenuate with use of CCS over time compared to MWS, although, scoliosis deteriorated regardless of intervention. CONCLUSIONS: Our findings showed paediatric wheelchair users with neurological and neuromuscular disorders prescribed CCS showed greater mitigation of scoliosis progression over time compared to those issued MWS.

Assessment of a New Elbow Joint Positioning Method Using Area Detector Computed Tomography.

We propose a sitting position that achieves both high image quality and a reduced radiation dose in elbow joint imaging by area detector computed tomography (ADCT), and we compared it with the 'superman' and supine positions. The volumetric CT dose index (CTDIvol) for the sitting, superman, and supine positions were 2.7, 8.0, and 20.0 mGy and the dose length products (DLPs) were 43.4, 204.7, and 584.8 mGy • cm, respectively. In the task-based transfer function (TTF), the highest value was obtained for the sitting position in both bone and soft tissue images. The noise power spectrum (NPS) of bone images showed that the superman position had the lowest value up to approx. 1.1 cycles/mm or lower, whereas the sitting position had the lowest value when the NPS was greater than approx. 1.1 cycles/mm. The overall image quality in an observer study resulted in the following median Likert scores for Readers 1 and 2: 5.0 and 5.0 for the sitting position, 4.0 and 3.5 for the superman position, and 4.0 and 2.0 for the supine position. These results indicate that our proposed sitting position with ADCT of the elbow joint can provide superior image quality and allow lower radiation doses compared to the superman and supine positions.

Comparison of induction of spinal anesthesia in sitting position with legs parallel and crossed for cesarean section: A randomized controlled trial.

Background and Aims: The position of the patient during subarachnoid block has a role in its success. Landmarks of the spine can be easily identified in sitting position. Sitting position with legs parallel (LPSP) produces a reversal of lumbar lordosis. The crossed-leg sitting position (CLSP) is an alternative position. In this study, we compared the ease of performing subarachnoid blocks in these two positions. The objectives were to compare the attempts at subarachnoid placement, patient comfort, ease of landmark palpation, level of block, hypotension, and neonatal outcomes. Material and Methods: This randomized trial was performed in 80 parturients posted for elective cesarean section. Parturients were assigned randomly to two groups. In group LPSP, the subarachnoid block was performed in sitting position with legs parallel and in group CLSP in the CLSP with knees and hips flexed. Results: The percentage of parturients with a successful subarachnoid block in the first attempt was higher in the CLSP than in LPSP group (87.5% versus 55%). The remaining 12.5% parturients in the CLSP group had successful block in the second attempt. In the LPSP group, 32.5% required two attempts and 12.5% required more than two attempts. This difference was statistically significant (P-value of 0.003). The landmark was easily palpable in 92.5 versus 67.5% of parturients in CLSP and LPSP, respectively, with a P-value of 0.014. Conclusion: CLSP is better than a sitting position with legs parallel for reducing the number of attempts and improving the ease of performing the subarachnoid block.

Comparison of neuraxial acoustic target window of the spine among rider sitting, cross leg, hamstring stretch, and classical sitting position: An observational study.

Background and Aims: To compare ultra-sonographic dimensions of acoustic target window of the spine in the participants at four different sitting positions namely cross leg sitting (CLP), hamstring stretch (HSP), classical sitting (CSP) and riders sitting position (RSP). The primary objective of this study was to measure the neuraxial acoustic target window (defined as interlaminar distance between L3-L4 lamina). The secondary objective was to compare ultra-sonographic measurements of the depth of ligamentum flavum from the skin, and to compare the diameter of intrathecal space and comfort score in the four different sitting positions. Material and Methods: This study is a prospective observational study. Eighty participants were included and positioned in four different sitting positions to perform an ultra-sonographic scan and measure various parameters of the acoustic neuraxial window. The interlaminar distance, the distance of skin from the ligamentum flavum, and the diameter of the spinal canal or intrathecal space was measured in the L3-L4 intervertebral space in different positions. Results: The mean value of interlaminar distance among four sitting positions was ranging from 1.40 cm to 1.44 cm (P value 0.725.) The distance of ligamentum flavum from skin and diameter of intrathecal space was also comparable in all the groups. The comfort score in CSP was significantly better when compared to other groups with a median score of 4 (P value < 0.001). Conclusions: There is no statistically significant difference in interlaminar distance in various sitting positions. All four positions are equally effective and can be used as an alternative to spinal/epidural intervention, but the CSP came out to be the most comfortable and more emphasis should be given to the comfort as it increases the chance of success rate of the procedure.

Benefits associated with the standing position during visual search tasks.

The literature on postural control highlights that task performance should be worse in challenging dual tasks than in a single task, because the brain has limited attentional resources. Instead, in the context of visual tasks, we assumed that (i) performance in a visual search task should be better when standing than when sitting and (ii) when standing, postural control should be better when searching than performing the control task. 32 and 16 young adults participated in studies 1 and 2, respectively. They performed three visual tasks (searching to locate targets, free-viewing and fixating a stationary cross) displayed in small images (visual angle: 22°) either when standing or when sitting. Task performance, eye, head, upper back, lower back and center of pressure displacements were recorded. In both studies, task performance in searching was as good (and clearly not worse) when standing as when sitting. Sway magnitude was smaller during the search task (vs. other tasks) when standing but not when sitting. Hence, only when standing, postural control was adapted to perform the challenging search task. When exploring images, and especially so in the search task, participants rotated their head instead of their eyes as if they used an eye-centered strategy. Remarkably in Study 2, head rotation was greater when sitting than when standing. Overall, we consider that variability in postural control was not detrimental but instead useful to facilitate visual task performance. When sitting, this variability may be lacking, thus requiring compensatory movements.

Resection of posterior fossa tumors in the semi-sitting position in children younger than 4 years of age.

PURPOSE: The semi-sitting position for resection of posterior fossa tumors is a matter of ongoing debate. Here we report about our experience with this approach in children younger than 4 years of age. METHODS: We retrospectively analyzed data of children younger than 4 years of age operated on in our institution in the semi-sitting position over a 15-year period. Patients were intraoperatively monitored for venous air embolism (VAE) by transthoracic Doppler (TTD) or transesophageal echocardiography (TEE). The severity of VAE was classified according to the Tübingen grading scale. Intraoperative incidents of VAE were recorded and the patients' course was followed postoperatively with a special focus on possible complications. RESULTS: Twenty-four children (18 boys, 6 girls) were operated on in the semi-sitting position (26 operations). Mean age was 2.2 years (± 1.0), range between 0.4 and 3.9 years. External ventricular drains were inserted in 18 children with hydrocephalus preoperatively. VAE was detected in 6 instances during surgery (6/26 (23.1%)). In 3 patients with grade 1 VAE, no additional treatment was necessary. In one patient with grade 2 VAE, intracardiac air suction via the central venous catheter was performed, and in two patients with grade 4 VAE, additional cathecholamine-infusion was administered. No major intraoperative complications occurred. Postoperative CT images showed pneumocephalus in all children. In two children, small asymptomatic impression skull fractures at the site of the Mayfield pin occurred. Revision surgery was necessary in one child with a suboccipital CSF fistula. CONCLUSION: The semi-sitting position for resection of tumors in the posterior fossa in children younger than 4 years of age can be safely performed in experienced centers taking special caution to detect and treat potential complications in an interdisciplinary setting.

The semi-sitting position in patients with indwelling CSF shunts: perioperative management and avoidance of complications.

OBJECTIVE: Posterior fossa or midline tumors are often associated with hydrocephalus and primary tumor removal with or without perioperative placement of an external ventricular drain (EVD) is commonly accepted as first-line treatment. Shunting prior to posterior fossa surgery (PFS) is mostly reserved for symptomatic cases or special circumstances. There are limited data regarding the anticipated risk for symptomatic pneumocephalus and the perioperative management using the semi-sitting position (SSP) in such a scenario. Here, we therefore assessed the safety of performing PFS in a consecutive series of patients over a period of 15 years to allow the elaboration of recommendations for perioperative management. METHODS: According to specific inclusion and exclusion criteria a total of 13 patients who underwent 17 operations was identified. Supratentorial pneumocephalus was evaluated with semiautomatic-volumetric segmentation. The volume of pneumocephalus was evaluated according to age and ventricular size. RESULTS: Ten of the 13 patients had a programmable valve (preoperative valve setting range 6-14 cmH20; mean 7.5 cmH20) while 3 patients had non programmable valves. A variable amount of supratentorial air collection was evident in all patients postoperatively (range 3.2-331 ml; mean 122.32 ml). Positive predictors for the volume of postoperative pneumocephalus were higher age and a preoperative Evans ratio > 0.3. In our series, we encountered no cases of tension pneumocephalus necessitating an air replacement procedure as well as no obstruction, disconnection, infection or hardware malfunction of the shunt system. CONCLUSIONS: Our findings indicate that a CSF shunt in situ is not a contraindication for performing PFS in the semi-sitting position and it does not increase the pre-existing risk for postoperative tension pneumocephalus. In cases of primary shunting for hydrocephalus associated with posterior fossa tumors a programmable valve set at a medium opening pressure with a gravitational device is a valid option when PFS in the semi-sitting position is opted. In patients with an indwelling shunt diversion system special caution is indicated in order to prevent and detect overdrainage especially in not adjustable valves or shunts without antisiphon devices.

Technical note: pre-positioning lower limb SSEP during semi-sitting positioning in posterior fossa surgery- does it matter?

Intra-operative monitoring has been a crucial tool in modern neurosurgery as it allows to optimize surgical outcome whilst reducing neurological deficits. Somatosensory evoked potentials are routinely monitored in most spinal and brain surgeries due to providing invaluable information regarding the functional integrity of sensory pathways. The use of this neurophysiological technique is particular useful when positioning patients in semi-sitting position during posterior fossa surgery. However, there is general agreement within the intra-operative neuromonitoring community that either upper or lower limb SSEPs monitoring typically suffice. Nonetheless, we report a case study of a patient in whom lower limb SSEPs were independently affected from upper limb SSEPs during positioning. In this respect, we suggest that both upper and lower limb SSEPs monitoring should be considered during semi-sitting positioning in patients undergoing posterior fossa surgery.

Effect of masticatory movements on head and trunk sways, and sitting and foot pressure distributions during sitting position.

BACKGROUND: The head plays an important role in the postural control. Chewing co-activates jaw and neck muscles leading to coordinated jaw and head-neck movements. Therefore, to examine effect of masticatory movements on head and trunk sways, and sitting and foot pressure distributions during mastication is helpful in the attempt to understand the interrelationship between stomatognathic function and posture control system in the sitting position. OBJECTIVES: The purpose of this study was to test the hypothesis in healthy subjects that masticatory movements affect head and trunk sways and sitting and foot pressure distributions during sitting position. METHODS: A total of 30 healthy male subjects with an average age of 25.3 years (range, 22-32 years) were evaluated. The CONFORMat™ and MatScan™ system were used to analyse changes in sitting pressure distribution center of sitting pressure (COSP) and changes in foot pressure distribution center of foot pressure (COFP), respectively, and the three-dimensional motion analysis system was used to analyse changes in head and trunk postures while subjects remained sitting position with rest position, centric occlusion and chewing. The total trajectory length of COSP/COFP, COSP/COFP area, and head and trunk sway values were compared between the three conditions to evaluate whether masticatory movement affected the stability of head and trunk sways and sitting and foot pressure distributions. RESULTS: Total trajectory length of COSP and COSP area during chewing were significantly shorter and smaller respectively than it was in rest position and centric occlusion (p ⟨ .016). Head sway value during chewing was significantly larger than it was in rest position and centric occlusion (p ⟨ .016). CONCLUSION: Masticatory movements affect sitting pressure distribution and head movements during sitting position.

The influence of sedentary behaviour on lumbar-pelvic kinematics during squatting and forward bending among physically active students.

Prolonged sitting may involve several mechanisms that make it a risk factor for low back pain. The aim of this study was to investigate lumbar-pelvic kinematics and multifidus muscle (MF) activity during squatting and forward bending in relation to the sedentary behaviour of physically active students. Sixty-three students were divided into two groups according to the time spent in a sitting position during the day: 'high' (>7 h/day); 'low' (≤7 h/day). Lumbar-pelvic ratios, ranges of motion, angular velocities, and MF flexion-relaxation phenomenon were investigated. Data were obtained using the optical motion analysis system, and surface electromyography. The results indicated that lumbar-pelvic ratios during both tasks and velocity of lumbar spine during squatting were significantly greater in the 'high' than in the 'low' sitting group. Muscle activity showed no differences between groups. Prolonged sitting can be considered a factor that slightly, but statistically significantly influences the lumbar-pelvic kinematics in physically active people.Practitioner summary: Lumbar-pelvic kinematics can be altered by prolonged sitting in physically active students. Lumbar-pelvic ratios during squatting and forward bending and lumbar spine velocity during squatting were significantly greater in the 'high' than in the 'low' sitting group. Sedentary behaviour should be considered during an assessment of movement patterns.Abbreviations: BMI: body mass index; ERR: extension-relaxation ratio; FRP: flexion-relaxation phenomenon; FRR: flexion-relaxation ratio; IPAQ: International Physical Activity Questionnaire; LBP: low back pain; METs: metabolic equivalent of tasks; MF: multifidus muscle; PA: physical activity; ROM: range of motion; sEMG: surface electromyography.

Parents' comfort and staffs' working-environment when infants are sitting skin-to-skin: a randomised controlled trial comparing a recliner and a hospital bed.

Skin-to-skin contact between parents and preterm infants is recommended because it has proven to be valuable for the infants' development and healing. However, it can be difficult to comply with this guideline and still ensure a good working environment for the staff.This randomised controlled trial compared a new recliner developed in collaboration with parents and staff with a hospital bed for use in neonatal and maternity care using parents' rating of own comfort/discomfort, self-reliance, and felt security, and the chair's/bed's functionality at two different days (Q1 and Q2) of hospitalisation. The physical work-environment was evaluated through a questionnaire to the staff.Ninety-seven parents and 53 health professionals participated. Parents had significantly lower discomfort, in the recliner at Q1 compared to the hospital bed. The staff had to twist and/or bend their back significantly less often when working at the recliner as compared to the hospital bed. Practitioner summary: Due to poor working environment, a participatory design project developed a new recliner that improved the possibility of infants having skin-to-skin contact with their parents. The recliner provided a better working-environment for the staff while focussing on improving comfort and self-reliance of the parents, as compared to a hospital bed. Abbreviations: NICU: Neonatal Intensive Care Unit; VELA: Vermund Larsen.

Examination of the correlation between the knee extension angles in the sitting and supine positions measured using ImageJ software: a prospective cross-sectional study.

[Purpose] We aimed to examine the correlation between the knee extension angles in the sitting and supine positions measured using ImageJ software. [Participants and Methods] A total of 50 legs in 25 healthy participants (17 males and 8 females) were included in our study. The knee extension angle was measured in the sitting and supine positions with the participants actively and maximally extending their knee joint on one side. The participants were photographed from the side with their knees centered in the image. Thereafter, the photographs were imported into the ImageJ image processing software to calculate the knee extension angles. [Results] The mean values of the knee extension angles in the sitting and supine positions were 131.5 ± 11.2° and 132.1 ± 12.2°, respectively, with a correlation coefficient of 0.85. No systematic errors were observed, and the minimal detectable change was 12.9°. [Conclusion] The knee extension angle in the sitting position showed a strong correlation with that in the supine position, with no systematic errors observed. Therefore, measurement of the knee extension angle in the sitting position can be an alternative to its measurement in the supine position.

Comparative effectiveness of lidocaine sprays between sitting and supine position for patients undergoing upper gastrointestinal endoscopy: a prospective randomized controlled trial.

BACKGROUND: Topical pharyngeal anesthesia has improved esophagogastroduodenoscopy (EGD) efficiency with smooth insertion, reducing pain and discomfort. Lidocaine spray is one of the safe and widely used methods. In practice, the patients walk, sit in a wheelchair, or lie on a trolley bed, and the lidocaine sprays are applied to those in sitting or supine positions for pre-endoscopic preparation. Although there is no current guidance technique, this study aims to compare the effects of lidocaine sprays between sitting (Group A; Gp A) and supine positions (Group B; Gp B) for patients undergoing unsedated EGD. METHODS: This study was a single-center prospective randomized controlled trial. Unsedated EGD patients were randomly allocated the lidocaine spray in sitting or lidocaine spray in the supine position. RESULTS: Lidocaine spray treatments were significantly different in the gag reflex (NRS; Gp A: 1.28 ± 0.67, Gp B: 1 ± 0.63, p = 0.0003), ease of esophageal instrumentation (NRS; Gp A: 7.68 ± 0.91, Gp B: 7.95 ± 0.66, p = 0.0042), and pain score (NRS; Gp A: 5.16 ± 2.08, Gp B: 4.53 ± 1.93, p = 0.0059). When considering modified Mallampati classification (MMC), MMC classes III and IV were significantly different in the same direction but MMC classes I and II were not. CONCLUSION: The technique of spraying in the supine position was associated with less gagging, less pain, and easier esophageal instrumentation, especially in patients with MMC classes III and IV.

Comparison of supine and upright face-to-face cadaver intubation.

INTRODUCTION: Optimal patient positioning during intubation improves laryngeal view and first pass success, as well as reducing incidence of hypoxia. In certain pre-hospital situations, it may be impractical or impossible for the operator to stand behind the patient. OBJECTIVE: We compared intubation in the supine and upright face-to-face positions, with regards to time to intubate and the view of the vocal cords obtained. METHODS: This was a pilot comparison study. One investigator intubated 25 cadavers with the use of a bougie in the supine and upright face-to-face positions. Each attempt was recorded on a video laryngoscope. Recordings of each attempt were reviewed by five blinded emergency physicians, who allocated both a percentage of glottic opening (POGO) score and Cormack-Lehane (CL) grade. Time to insertion of the endotracheal tube (ETT) through the vocal cords was measured from the video. RESULTS: The median intubation time was 1 s longer for upright cadavers than for supine cadavers, with greater variation in intubation times for upright cadavers compared with supine cadavers (IQR 9.0 vs 3.5 excluding the outlier case). The mean POGO score (averaged across raters) was 4.7% lower for upright intubation attempts (excluding the outlier case) with a moderate-to-good degree of inter-rater reliability, however this difference was not statistically significant. The median CL grade (averaged across raters) was 0.2 higher for upright intubation attempts (excluding the outlier case) with a poor-to-moderate degree of inter-rater reliability, and this difference was also not statistically significant. CONCLUSIONS: This pilot study suggests that upright, face-to-face intubation may be clinically similar to supine intubation in terms of time to intubation and difficulty. Further studies utilising a larger number of operators and cadaver types are indicated.

Physical activity and sitting time in occupational groups from Papua New Guinea.

PURPOSE: To assess physical activity and sitting time in workers from varied occupations in a regional urban population of Papua New Guinea (PNG), to identify priorities for worker health in a country experiencing rapid industrial development. METHODS: PNG workers from a variety of settings (office [n = 213], blue-collar [n = 131], and retail [n = 52]) completed an interviewer-administered demographic questionnaire, the International Physical Activity Questionnaire-short form (IPAQ) and the Occupational Sitting and Physical Activity Questionnaire (OSPAQ); and had height and weight measured. Comparison of activity and sitting time between occupational groups was undertaken using generalised linear equations, with models including demographic variables and sitting time/physical activity as appropriate. RESULTS: Participants reported median total physical activity (walking, moderate and vigorous PA) of 5025 MET-min/week (80% constituting walking) and over 97% of participants met physical activity guidelines (> 600 MET-min/week). Total sitting time was 7 hours/day (IPAQ) and workers sat for 50% of working hours (OSPAQ). There was no difference between groups total physical activity. Office workers reported more total sitting time and a greater proportion of their work time spent sitting than blue-collar and retail workers reported significantly less total sitting time both p < 0.001) and retail workers reported a greater proportion of their work hours standing than office workers and blue-collar workers. CONCLUSIONS: Sitting time in PNG office workers was high, similar to findings from high-income countries, but total physical activity was also high in all groups. As the PNG economy develops and office-based work becomes more prevalent, the challenge will be to minimise sitting time at work whilst maintaining high total physical activity.

Do the three-dimensional parameters of brace-wearing patients with AIS change when transitioning from standing to sitting position? A preliminary study on Lenke I.

BACKGROUND: Bracing is the most common conservative treatment for preventing the progression of adolescent idiopathic scoliosis (AIS) in patients with a curve of 25°-40°. X-ray examinations are traditionally performed in the standing position. However, school-age teenagers may take more time to sit. Thus far, little is known about three-dimensional (3D) correction in the sitting position. Hence, this study aimed to determine the effects of standing and sitting positions on 3D parameters during brace correction. METHODS: We evaluated a single-center cohort of patients receiving conservative treatment for thoracic curvature (32 patients with AIS with a Lenke I curve). The 3D parameters of their standing and sitting positions were analyzed using the EOS imaging system during their first visit and after bracing. RESULTS: At the patients' first visit, sagittal plane parameters such as thoracic kyphosis (TK), lumbar lordosis (LL), and sacral slope decreased when transitioning from the standing position to the sitting position (standing 29° ± 6°, 42° ± 8°, and 42° ± 8° vs. sitting 22° ± 5°, 27° ± 6°, and 24° ± 4°; p < 0.001), whereas pelvic tilt (PT) increased and sagittal vertical axis shifted forward (standing 9° ± 6° and 1.6 ± 2.7 cm vs. sitting 24° ± 4° and 3.8 ± 2.3 cm; p < 0.001). After bracing, TK and LL decreased slightly (from 29° ± 6° and 42° ± 8° to 23° ± 3° and 38° ± 6°; p < 0.001), whereas the thoracolumbar junction (TLJ) value increased (from 3° ± 3° to 11° ± 3°; p < 0.001). When transitioning to the sitting position, similar characteristics were observed during the first visit, except for a subtle increase in the TLJ and PT values (standing 11° ± 3° and 9° ± 4° vs. sitting 14° ± 3° and 28° ± 4°; p < 0.001). Moreover, the coronal and axial parameters at different positions measured at the same time showed no significant change. CONCLUSIONS: In brace-wearing patients with thoracic scoliosis, compensatory sagittal plane straightening may be observed with a slight increase in thoracolumbar kyphosis, particularly when transitioning from the standing position to the sitting position, due to posterior rotation of the pelvis. Our results highlight that sagittal alignment in AIS with brace treatment is not completely analyzed with only standing X-Ray. TRIAL REGISTRATION: The study protocol was registered with the Chinese Clinical Trial Registry (ChiCTR1800018310).

Pineal region tumours in the sitting position: how I do it.

BACKGROUND: Pineal region tumours remain challenging neurosurgical pathologies. METHODS: Detailed anatomical knowledge of the posterior incisural space and its variations is critical. An opaque arachnoidal membrane seals the internal cerebral and basal veins, leading to thalamic, basal ganglia, mesencephalic/pontine infarctions if injured. Medium-size tumours can be removed en-bloc with all traction/manipulation applied on the tumour side, virtually without contact of ependymal surfaces of the pulvinars or third ventricle. Sacrifice of the cerebello-mesencephalic fissure vein may be required. CONCLUSIONS: The sitting position offers superior anatomical orientation and remains safe with experienced teams. Meticulous microsurgical techniques and detailed anatomical knowledge are likely to secure safe outcomes.

Pelvic and spinal postural changes between standing-sitting positions following lumbosacral fusion: a pilot study.

PURPOSE: Prospective pre-operative and post-operative comparative analysis of radiographic spino-pelvic parameters between sitting versus standing positions of patients with LS fusion, to detect adaptation mechanisms around fused spinal segments. METHODS: Sixteen patients aged 53.9 ± 15.9 who underwent LS fusion between L3 and S1 were extracted from the database of an ongoing prospective study. Different spino-pelvic parameters were evaluated on full spine X-rays, standing, then sitting straight. Parameters were compared pre-operative versus post-operative, and on standing versus sitting X-rays. RESULTS: Preliminary results revealed a significantly greater pre-operative pelvic tilt (PT) in sitting than standing posture, (p = 0.020) but not in post-operative (p = 0.087). After surgery, PT was lower in sitting compared to pre-operative (p = 0.034) but not in standing (p = 0.245). L4-S1 lordosis was lower in sitting than standing in pre-operative (p = 0.014) and post-operative (p = 0.021). Surgery decreased segmental lordosis above the fusion (PSL, proximal sagittal lordosis) in sitting (p = 0.039) but not in standing (p = 0.193). No significant differences in thoracic kyphosis (TK) were observed. Fusions down to L5 versus S1 showed no significant differences for PT and PSL, neither in sitting versus standing, nor pre-operative versus post-operative. CONCLUSION: Before fusion, compared to standing, PT increases in sitting straight posture (pelvic retroversion), and the lumbar spine adapts by decreasing its lordosis, mainly at L4-S1. After fusion, the segments adjacent to the instrumented section, adapt in flexion at lumbosacral and thoracolumbar junctions, i.e. just below and above (PSL). This might have mechanical implications for the occurrence of adjacent segment disease.

[Sitting position in neurosurgery: realizing the risks]. / Neirokhirurgicheskie vmeshatel'stva v polozhenii sidya: real'no otsenivaya riski.

The author discusses potential intraoperative complications following neurosurgical interventions in sitting position: venous air embolism and paradoxical air embolism, postural hypotension, pneumocephalus, cervical flexion neuropathy, positional damage to peripheral nerves and others. Naturally, prevention of these complications is also considered, and the most effective approach is surgery in lying position.

Novel Equations to Estimate Resting Energy Expenditure during Sitting and Sleeping.

INTRODUCTION: Young and early middle-aged office workers spend most of the day sitting or sleeping. Few studies have used a metabolic chamber to report sitting resting energy expenditure (REE) or sleeping metabolic rate (SMR) estimation equations. This study aimed to develop novel equations for estimating sitting REE and SMR, and previously published equations for SMR were compared against measured values. METHODS: The relationships among sitting REE, SMR, and body composition measured in clinical trials were analyzed. The body composition (fat-free mass [FFM] and fat mass) and energy metabolism of 85 healthy young and early middle-aged Japanese individuals were measured using dual-energy X-ray absorptiometry and a metabolic chamber, respectively. Novel estimate equations were developed using stepwise multiple regression analysis. Estimates of SMR using a new equation and 2 published equations were compared against measured SMR. RESULTS: The sitting mREE and mSMR were highly correlated (r = 0.756, p < 0.01). The new FFM-based estimate accounted for 50.4% of the variance in measured sitting REE (mREE) and 82.3% of the variance in measured SMR (mSMR). The new body weight-based estimate accounted for 49.3% of the variance in sitting mREE and 82.2% of the variance in mSMR. Compared with mSMR, the SMR estimate using an FFM-based published equation was slightly underestimated. CONCLUSION: These novel body weight- and FFM-based equations may help estimate sitting REE and SMR in young and early middle-aged adults. Previous SMR estimated FFM-based equations were slightly underestimated against measured SMR; however, we confirmed the previous SMR estimate equations could be useful. This finding suggests that sitting REE and SMR can be easily estimated from individual characteristics and applied in clinical settings.