Preoperative spinopelvic hypermobility resolves following total hip arthroplasty.

AIMS: Spinopelvic mobility plays an important role in functional acetabular component position following total hip arthroplasty (THA). The primary aim of this study was to determine if spinopelvic hypermobility persists or resolves following THA. Our second aim was to identify patient demographic or radiological factors associated with hypermobility and resolution of hypermobility after THA. METHODS: This study investigated patients with preoperative posterior hypermobility, defined as a change in sacral slope (SS) from standing to sitting (ΔSSstand-sit) ≥ 30°. Radiological spinopelvic parameters, including SS, pelvic incidence (PI), lumbar lordosis (LL), PI-LL mismatch, anterior pelvic plane tilt (APPt), and spinopelvic tilt (SPT), were measured on preoperative imaging, and at six weeks and a minimum of one year postoperatively. The severity of bilateral hip osteoarthritis (OA) was graded using Kellgren-Lawrence criteria. RESULTS: A total of 136 patients were identified as having preoperative spinopelvic hypermobility. At one year after THA, 95% (129/136) of patients were no longer categorized as hypermobile on standing and sitting radiographs (ΔSSstand-sit < 30°). Mean ΔSSstand-sit decreased from 36.4° (SD 5.1°) at baseline to 21.4° (SD 6.6°) at one year (p < 0.001). Mean SSseated increased from baseline (11.4° (SD 8.8°)) to one year after THA by 11.5° (SD 7.4°) (p < 0.001), which correlates to an 8.5° (SD 5.5°) mean decrease in seated functional cup anteversion. Contralateral hip OA was the only radiological predictor of hypermobility persisting at one year after surgery. The overall reoperation rate was 1.5%. CONCLUSION: Spinopelvic hypermobility was found to resolve in the majority (95%) of patients one year after THA. The increase in SSseated was clinically significant, suggesting that current target recommendations for the hypermobile patient (decreased anteversion and inclination) should be revisited. Cite this article: Bone Joint J 2021;103-B(12):1766-1773.

Two-year outcomes of the ARTISAN-SNM study for the treatment of urinary urgency incontinence using the Axonics rechargeable sacral neuromodulation system.

AIMS: Sacral neuromodulation (SNM) is a guideline-recommended treatment with proven therapeutic benefit for urinary urgency incontinence (UUI) patients. The Axonics® System is the first Food and Drug Administration-approved rechargeable SNM system and is designed to deliver therapy for a minimum of 15 years. The ARTISAN-SNM study was designed to evaluate UUI participants treated with the Axonics System. Two-year follow-up results are presented. METHODS: One hundred and twenty-nine UUI participants underwent implantation with the Axonics System. Therapeutic response rate, participant quality of life (QoL), and satisfaction were determined using 3-day voiding diaries, ICIQ-OABqol, and satisfaction questionnaires. Participants were considered responders if they had a 50% or greater reduction in UUI episodes post-treatment. As-treated and Completers analyses are presented. RESULTS: At 2 years, 93% of the participants (n = 121 Completers at 2 years) were therapy responders, of which 82% achieved ≥ 75% reduction in UUI episodes and 37% were dry (100% reduction). Daily UUI episodes reduced from 5.6 ± 0.3 at baseline to 1.0 ± 0.2 at 2 years. Statistically significant improvements in ICIQ-OABqol were reported. All participants were able to recharge their device and 94% of participants reported that the recharging frequency and duration were acceptable. Participant demographics nor condition severity were correlated with clinical outcomes or recharging experience. No unanticipated or serious device-related adverse events occurred. CONCLUSIONS: At 2 years, participants treated with the Axonics System demonstrated sustained safety and efficacy, high levels of satisfaction with therapy and recharging. Participant-related factors were not associated with efficacy or recharging outcomes, indicating the reported results are applicable to a diverse population.

Effects of cycle periods and pressure amplitudes of alternating pressure on sacral skin blood flow responses.

BACKGROUND: There are no guidelines on selecting alternating pressure (AP) configurations on increasing sacral skin blood flow (SBF). AIM: The specific aims were to compare different cycle periods and pressure amplitudes of AP on sacral SBF responses in healthy people to establish the efficacy and safety of the protocols. METHODS: Two studies were tested, including the cycle period study (8 2.5-min vs 4 5-min protocols) and the pressure amplitude study (75/5 vs 65/15 mmHg protocols). Sacral SBF was measured using laser Doppler flowmetry (LDF) in 20 participants. AP loads were randomly applied using an indenter through the rigid LDF probe. Each protocol included a 10-min baseline, 20-min AP and 10-min recovery periods. A 30-min washout period was provided. The SBF response was normalized to the baseline SBF of each condition of each participant. RESULTS: For the cycle period study, the 4 5-min cycle protocol partially restored more SBF than the 8 2.5-min cycle protocol at the low-pressure phase (0.87 ± 0.04 vs 0.71 ± 0.03, p < 0.05) and at the high-pressure phase (0.25 ± 0.03 vs 0.19 ± 0.03, p < 0.05). For the pressure amplitude study, the 75/5 mmHg protocol partially restored more sacral SBF than the 65/15 mmHg protocol at the low-pressure phase (0.87 ± 0.1 vs 0.25 ± 0.03, p < 0.05) but not at the high-pressure phase (0.23 ± 0.02 vs 0.21 ± 0.02, non-significant). CONCLUSION: This study demonstrated that 1) a cycle period of 5 min was better than 2.5 min and 2) a pressure amplitude of 75/5 mmHg was better than 65/15 mmHg. The finding provides insights for selecting the AP configurations for increasing SBF.

Unilateral versus bilateral sacral neuromodulation test in the treatment of refractory idiopathic overactive bladder: A randomized controlled pilot trial.

AIM: To compare treatment success rate in terms of improvement of bladder overactivity between unilateral and bilateral sacral neuromodulation testing. METHODS: A multicentric, parallel, randomized, open pilot trial (October 2012-September 2017) was conducted. Participants presented primary overactive bladder resistant to first-line treatments. Patients were excluded in case of secondary bladder, pelvic, or neurological condition. Patients were randomized between bilateral testing (n = 28) or unilateral testing (n = 27), to determine the best functional response before final implantation. The primary outcome was the rate of patients presenting at least 50% of clinical improvement at 1 month on urinary frequency, number of urge incontinence episodes or number of urinary urgency episodes. Symptom severity, implantation success rate, uroflowmetry, device tolerance, complications, and quality of life were also assessed. RESULTS: Fifty-five patients have been included. The rate of patients presenting at least one significant clinical improvement at month 1 was 62% in the bilateral group versus 84% in the unilateral group (P = .0891), RR = 0.74 (0.51; 1.07). There was no significant difference between bilateral and unilateral groups in terms of improvement of urinary frequency (0% and 17%; P = .1115), number of urge incontinence episodes (52% and 63%; P = .4929) or number of urinary urgency episodes (57% and 74%; P = .2411). More complications were reported in the bilateral group than in the unilateral group (9 [47%] vs 4 [16%], respectively; P = .0239). CONCLUSION: Systematic bilateral sacral neuromodulation testing before final implantation did not appear to increase success rate compared with unilateral stimulation in the treatment of overactive bladder.

Examination of the changes in lower extremities related to progression of adult spinal deformity: a longitudinal study of over 22 years.

This longitudinal observational study investigated the relationship between changes in spinal sagittal alignment and changes in lower extremity coronal alignment. A total of 58 female volunteers who visited our institution at least twice during the 1992 to 1997 and 2015 to 2019 periods were investigated. We reviewed whole-spine radiographs and lower extremity radiographs and measured standard spinal sagittal parameters including pelvic incidence [PI], lumbar lordosis [LL], pelvic tilt [PT], sacral slope [SS] and sagittal vertical axis [SVA], and coronal lower extremity parameters including femorotibial angle (FTA), hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA) and mechanical lateral distal tibial angle (mLDTA). Lumbar spondylosis and knee osteoarthritis were assessed using the Kellgren-Lawrence (KL) grading system at baseline and at final follow-up. We investigated the correlation between changes in spinal sagittal alignment and lower extremity alignment and changes in lumbar spondylosis. The mean age [standard deviation (SD)] was 48.3 (6.3) years at first visit and 70.2 (6.3) years at final follow-up. There was a correlation between changes in PI-LL and FTA (R = 0.449, P < 0.001) and between PI-LL and HKA (R = 0.412, P = 0.001). There was a correlation between changes in lumbar spondylosis at L3/4 (R = 0.383, P = 0.004) and L4/5 (R = 0.333, P = 0.012) and the knee joints. Changes in lumbar spondylosis at L3/4 and L4/5 were related to changes in KOA. Successful management of ASD must include evaluation of the state of lower extremity alignment, not only in the sagittal phase, but also the coronal phase.

Sacral stress fracture in an amateur golf player: a case report and literature review.

Sacral stress fractures are rare injuries among professional and amateur athletes and are considered to be an uncommon source of low back pain. These type of fractures are mainly seen in competitive, high-impact sports, most commonly in long-distance runners. Sacral stress fractures are usually overlooked in young patients presenting with low back pain without any trauma history. Diagnosis of sacral stress fractures is often delayed because the history and physical examination of these patients are not specific and conventional radiographic images are frequently inadequate. A high index of clinical suspicion and further radiologic imaging such as MRI utilization can provide the accurate diagnosis. The treatment mainly includes rest, pain control, nutritional support, and biomechanical optimization. Herein, we report the case of a woman amateur golf player with a sacral stress fracture who complained of aggravating low back pain. To the best of our knowledge, this appears to be the first report of a sacral stress fracture in a golf player and also the first case of this pathology in low-impact sports. Therefore, physicians should keep in mind that stress fractures can also be seen in low-impact sports. We recommend considering stress fractures in the differential diagnosis of non-traumatic, aggravating low back pain in golfers.

Limited correction of lumbar lordosis in the treatment of degenerative scoliosis.

BACKGROUND: Patients suffering from degenerative scoliosis (DS) were commonly associated with coronal and sagittal imbalance which made deformity correction surgery necessary. The study aimed to explore the efficacy and feasibility of the limited correction of lumbar lordosis (LL) in the treatment of patients with DS. METHODS: This was a retrospective study including 58 DS patients who underwent spinal deformity correction surgery and were followed up at least 2 years between January 2013 and January 2017. According to the difference of postoperative LL, the patients were divided into 2 groups: the limited correction group: Pelvic incidence(PI)-18°≤ LL .05). In terms of surgery, the limited group had less intra-operative blood loss and operation time (P < .05). At the last follow-up, significant differences were found in terms of LL(-38.2 ±â€Š4.7° and -46.9 ±â€Š4.7°), PT (18.8 ±â€Š5.2° and 11.1 ±â€Š3.6°), sacrum slope (33.7 ±â€Š7.0° and 41.4 ±â€Š6.1°) (P < .05), while there were no significant differences in terms of lumbar Cobb angle (10.5 ±â€Š9.3°and 8.3 ±â€Š6.7°), Oswestry Disability Index scores (25.6 ±â€Š10.2 and 26.4 ±â€Š12.1), and JOA scores (23.6 ±â€Š5.2 and 22.3 ±â€Š5.7) (P > .05). CONCLUSION: Limited correction of LL in the treatment of DS patients can achieve favorable clinical outcomes including effective Cobb angle correction with less blood loss and operative time.

Vacuum phenomenon in pelvic fractures.

BACKGROUND: Vacuum phenomenon (VP) in closed pelvic fracture is a rare disorder. This study aimed to examine the prevalence and clinical findings of VP in closed pelvic fracture. METHODS: We retrospectively reviewed 197 patients with closed pelvic fracture who presented to our institution from January 2012 to December 2018. Pelvic fractures were diagnosed by plain radiography and computed tomography (CT). First, we investigated the prevalence and clinical findings of VP in pelvic fractures. Second, we compared the clinical findings between pelvic fracture with and without VP. Finally, VP in pelvic fracture was evaluated clinically and radiologically. RESULTS: VP in pelvic fractures was detected by CT in 9 (3.6%) of the 197 patients with pelvic fractures. Patients with VP had a significantly greater proportion of fracture progression than those without VP (42.9% vs. 11.3%, P = 0.02). Patients with VP had a greater proportion of fragility fractures of the pelvis (FFP), and a lesser proportion of bone union than those without VP, although the differences were not significant. In nine pelvic fractures with VP, all sacral fractures were classified as type 1 according to the Denis classification, and all pubic fractures were classified as type 1 according to the Nakatani classification. Two (22.2%) nonunion in nine pelvic fractures with VP occurred at the pubic fracture site alone. CONCLUSIONS: Orthopedic clinicians should be aware of the potential of CT for detecting VP in pelvic fractures, especially in the course of FFP progression.

The mechanism of persistent undermining of a sacral pressure ulcer: Experimental analyses using a deformable model and examination of skin mobility over different anatomical locations.

Undermining is an important issue in the treatment and care of deep pressure ulcers. The frequency of the undermining over different bony prominences varies. In particular, deep pressure ulcers over the sacrum exhibit undermining more frequently than those occurring over the heel. Although shear force has been suggested as a critical factor in undermining, the exact mechanism remains unclear due to ethical and technical reasons in clinical practice. To clarify this issue, a deformable model was constructed to recreate the physical and morphological properties of a pressure ulcer with persistent undermining. The model was constructed using urethane to recreate the physical properties of a pressure ulcer. To examine the clinical relevance of the model, mechanical properties of the skin and the model were measured using a durometer. The model was further mounted onto a phantom that was laid on a bed. Backrest elevation of the bed induced deformities in the urethane model, suggesting a mechanism of persistent undermining of the sacral pressure ulcer. Moreover, a simple palpation examination in elderly volunteers revealed that the skin over the sacrum was more mobile than the skin over the heel. Therefore, persistent undermining is likely caused by specific external forces and the characteristic skin mobility of the sacral region. These two different factors explain the frequent undermining that occurs in sacral pressure ulcers.

Evolution of Fatigue Damage in the L5-S1 Intervertebral Disc Resulting from Walking Exposures Among Persons with Lower Limb Loss.

The risk of fatigue damage within the L5-S1 spinal disc was calculated for a sample of 52 individuals with unilateral limb loss (26 transtibial; 26 transfemoral) and 26 uninjured controls using a non-linear multi-axial fatigue model of the spine motion segments. Time to complete damage was calculated for each participant and walking pace; the influences of walking activity were determined by varying daily step counts. Assuming similar activity across groups (10,000 steps per day), times to failure were not different between persons with and without limb loss (50 [23] vs. 46 [24] years, respectively); walking faster was associated with shorter times to failure. Greater daily step counts similarly decreased time to failure in all groups. While such a similarity in fatigue damage evolution does not necessarily downplay the role of biomechanical factors, it may highlight the important influences of psychosocial factors in the development of low back pain in persons with limb loss. Nevertheless, with additional work to include activities beyond walking, computational damage models can provide a predictive platform for evaluating specific clinical interventions (e.g., behavior modification, movement retraining, prosthetic devices) that are ultimately intended to mitigate physical risk factors for low back pain following limb loss.

The association between sacral morphology and sacroiliac joint conformity demonstrated on CT-based bone models.

INTRODUCTION: Knowledge of the stress distribution on structures around the sacroiliac joint (SIJ) is required to treat or prevent SIJ disorders. The purpose of this study was to reveal the association between sacral morphology and SIJ conformity. MATERIALS AND METHODS: This cross-sectional study included 11 adult patients with unilateral SIJ pain who underwent computed tomography (CT) imaging of the pelvis. Bony coordinate systems for the sacrum and innominates were embedded using anatomical landmarks. Local coordinate systems for the auricular surfaces of the sacrum and innominate were also defined. Conformity of the SIJ was quantified by the offset of the coordinate systems between the auricular surfaces of the sacrum and innominate. Repeated measure ANOVA and multiple regression analysis were used for statistical analyses. RESULTS: There were large variations across subjects in sacral morphology and SIJ conformity. There were no differences in any of the six degrees-of-freedom positions or orientations of the bilateral sacral and innominate auricular surfaces between the symptomatic and asymptomatic sides. The SIJ downward rotation on the asymptomatic and symptomatic sides were 0.0 [-1.0, 1.1]° and 2.1 [1.2, 3.0]°, respectively. Smaller downward rotation of the sacral auricular surface based on the sacral bony coordinate system had significant association with the greater SIJ downward rotation (standard partial regression coefficient: -.44, p = .043). CONCLUSIONS: The results indicate that the morphology of the sacrum is associated with poor SIJ conformity and that separation of the superior portion of the SIJ can be a risk factor for SIJ pain.

How do global sagittal alignment and posture change after total hip arthroplasty?

BACKGROUND: Postural change after total hip arthroplasty (THA) is still a matter of discussion. Previous studies have mainly concentrated on the pelvic motions. We report the post-operative changes of the global sagittal posture using pelvic, spinal, and lower extremities parameters. METHODS: 139 patients (primary THA, without previous spinal or lower extremity surgery) were included. We measured pelvic parameters [SS, sacral slope; PI, pelvic incidence; PT, pelvic tilt; APP angle, anterior pelvic plane angle] and the global posture parameters (SVA, sagittal vertical angle; GSA, global sagittal angle; TPA, T1 pelvic angle). Patients were categorized into low PI group < 45°, 45° < medium PI < 65°, and high PI > 65°. RESULTS: Mean GSA and SVA decreased post-operatively (p = 0.005 and p = 0.004 respectively). The TPA change was not significant (p = 0.078). In the low PI group, GSA (5.4 ± 5.0 to 4.3 ± 4.0, p = 0.005) and SVA (5.4 ± 4.9 to 4.2 ± 4.1, p = 0.038) decreased with more posterior pelvic tilt. Post-operative TPA was significantly higher (8.4 ± 10.6 to 9.8 ± 10.7; p = 0.048). In the medium PI group, SVA decreased (4.2 ± 4.6 to 3.6 ± 4.5, p = 0.020) with more posterior pelvic tilt. In the high PI group, pelvic and global posture parameters did not evolve significantly. CONCLUSION: PI is the key determining factor in pelvic tilt modification after THA. Patients with low PI demonstrate significant modification in spine, pelvic, and lower extremities. Pelvic tilt is the main adaptation mechanism for medium incidence patients whereas pelvic tilt does not change in high PI patients after surgery.

New Technologies and Applications in Sacral Neuromodulation: An Update.

Recently rechargeable devices have been introduced for sacral neuromodulation (SNM) with conditional safety for full-body magnetic resonance imaging (MRI). Currently a recharge-free SNM device represents the standard implant; however, it is only approved for MRI head scans. As further new technologies with broader MRI capabilities are emerging, the advantages as well as disadvantages of both rechargeable versus recharge-free devices will be briefly discussed in this commentary from the perspective of patients, healthcare professionals, and providers.

Nerve transfer for restoration of lower motor neuron-lesioned bladder and urethra function: establishment of a canine model and interim pilot study results.

OBJECTIVE: Previous patient surveys have shown that patients with spinal cord or cauda equina injuries prioritize recovery of bladder function. The authors sought to determine if nerve transfer after long-term decentralization restores bladder and sphincter function in canines. METHODS: Twenty-four female canines were included in this study. Transection of sacral roots and hypogastric nerves (S Dec) was performed in 6 animals, and 7 animals underwent this procedure with additional transection of the L7 dorsal roots (L7d+S Dec). Twelve months later, 3 L7d+S Dec animals underwent obturator-to-pelvic nerve and sciatic-to-pudendal nerve transfers (L7d+S Dec+Reinn). Eleven animals served as controls. Squat-and-void behaviors were tracked before and after decentralization, after reinnervation, and following awake bladder-filling procedures. Bladders were cystoscopically injected with Fluoro-Gold 3 weeks before euthanasia. Immediately before euthanasia, transferred nerves were stimulated to evaluate motor function. Dorsal root ganglia were assessed for retrogradely labeled neurons. RESULTS: Transection of only sacral roots failed to reduce squat-and-void postures; L7 dorsal root transection was necessary for significant reduction. Three L7d+S Dec animals showing loss of squat-and-void postures post-decentralization were chosen for reinnervation and recovered these postures 4-6 months after reinnervation. Each showed obturator nerve stimulation-induced bladder contractions and sciatic nerve stimulation-induced anal sphincter contractions immediately prior to euthanasia. One showed sciatic nerve stimulation-induced external urethral sphincter contractions and voluntarily voided twice following nonanesthetized bladder filling. Reinnervation was confirmed by increased labeled cells in L2 and the L4-6 dorsal root ganglia (source of obturator nerve in canines) of L7d+S Dec+Reinn animals, compared with controls. CONCLUSIONS: New neuronal pathways created by nerve transfer can restore bladder sensation and motor function in lower motor neuron-lesioned canines even 12 months after decentralization.

Evaluation of clinical efficacy of silver-needle warm acupuncture in treating adults with acute low back pain due to lumbosacral disc herniation: study protocol for a randomized controlled trial.

BACKGROUND: As a common cause of low back pain, lumbosacral disc herniation (LDH) is usually dealt with using non-surgical interventions. In the face of concerns about prescription opioid abuse, alternative and complementary treatments may be promising, among which silver-needle warm acupuncture is considered as an upgrading option for its potential anti-inflammatory and strong analgesic effect for patients with chronic pain. In this proposed study, we aim to assess its clinical efficacy in comparison with conventional stainless steel filiform-needle warm acupuncture. METHODS/DESIGN: This is a randomized, two-armed, patient- and assessor-blinded trial. One hundred and sixty eligible patients recruited from December 2018 to June 2020 in three centers will be assigned for warm acupuncture treatment with either stainless steel filiform or silver needles. Nine sessions of 20-min treatment will be conducted during 3 consecutive weeks. Assessments with instruments including the Oswestry Disability Index, the visual analog scale, and the Japanese Orthopedic Association Back Pain Evaluation Questionnaire will be performed at four time points to explore the difference of clinical efficacy between two groups. DISCUSSION: If the results show that participants treated with silver-needle warm acupuncture gain a greater improvement in terms of pain intensity, physical function, and quality of life, this study is expected to offer reliable evidence to widely push this treatment for LDH in clinical practice. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800019051 . Registered on 24 October 2018.

Differential response to vibration of three forms of scoliosis during axial cyclic loading: a finite element study.

BACKGROUND: Scoliosis is a serious disease that can affect all segments of society. Few studies have investigated the response to vibration of differing sinusoidal axial cyclic loading frequencies for different forms of scoliosis in the lumbar spine. METHODS: In this study, four finite element models, comprising a healthy spine, Lenke-A, Lenke-B and Lenke-C scoliosis of the lumbar S1-L1 region were developed. Modal analysis extracted resonant frequencies of the FE models with an upper body mass of 40 kg and 400 N preload. A transient dynamic analysis was performed to obtain the response to vibration of models under a sinusoidal axial loading of ± 40N at frequencies of 3, 5, 7, 9, 11 and 13 Hz using an upper body mass of 40 kg and 400 N preload. RESULTS: The first-order resonant frequencies of healthy, Lenke-A, Lenke-B and Lenke-C spines were 9.2, 3.9, 4.6 and 5.7 Hz, respectively. A Lenke-A lumbar spine was more likely to deform at a lower vibration frequency and Lenke-C deformed more easily at a higher vibration frequency. Furthermore, the vibration amplitude in the Y-direction (left-right) was greatest and least in the Z-direction (top-bottom). The frequency of cyclic loading closest to the resonant frequency resulted in a maximum value of peak-to-peak vibrational displacement. Furthermore, the vibrational amplitudes in patients with scoliosis were larger than they were in healthy subjects. In addition, axial displacement of the vertebrae in the healthy spine changed steadily whereas fluctuations in the scoliotic vertebrae in scoliosis patients were greater than that of other vertebrae. CONCLUSIONS: Different forms of scoliosis may have different vibrational characteristics, the scoliotic vertebrae being the weak link in scoliosis under loading condition of whole body vibration. Scoliosis was more sensitive to this form of vibration. Where the frequency of axial cyclic vibrational loading of the lumbar spine was closer to its resonant frequency, the vibrational amplitude was larger. These results suggest that vibration will exacerbate the degree of scoliosis and so such patients should reduce their exposure to vibration. Clinical treatment should pay attention to the scoliotic vertebrae and reduce their vibration. These findings may assist in the clinical prevention and treatment of scoliosis.

Evaluating thoracolumbar spine response during simulated underbody blast impact using a total human body finite element model.

In a study of spine injuries in Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) from 2001-09, spinal fractures sustained by mounted soldiers accounted for 26% of all injuries, and of that, 43% were caused by explosions [1]. The thoracolumbar region is the most vulnerable area of the spine [2], and injuries are often incapacitating, making egress from vehicles difficult. Injury prediction from such events continues to remain a challenge due to the limited availability of studies specifically focused on underbody blasts (UBB) and criteria on related injuries. This study focuses on developing and validating the spine response of an updated 50th percentile male Global Human Body Models Consortium (GHBMC) Finite Element (FE) model using instrumented post-mortem human subject (PMHS) laboratory tests under two unique conditions. The model was validated against response corridors created using scaled thoracic (T12, T8, T5, T1) and sacrum (S1) spine Z-axis accelerations obtained from WSU whole-body PMHS tests. The scores for the updated spine model ranged from 0.557 - 0.756 for condition 1 (Seat- 4 m/s in 10 ms; Floor- 6 m/s in 5 ms) and 0.639-0.849 for condition 2 (Seat- 4 m/s in 55 ms; Floor- 8 m/s in 2 ms). The PMHS tests sustained spinal injuries in the thoracolumbar region. The validated model indicates high stress and strain concentrations at the same locations, providing an explanation for the fractures sustained in the PMHS tests.

Cement augmentation of sacroiliac screws in fragility fractures of the pelvic ring-A synopsis and systematic review of the current literature.

BACKGROUND: Fragility fractures of the pelvis (FFP) show a notable rise in prevalence. Minimally invasive surgical fixation of FFP is increasingly advocated for its obvious advantages with reference to early mobilization and weight bearing. Concerns regarding the holding power of osteosynthetic materials in osteoporotic bone led to the development of cementing techniques. However, the role of cement augmentation in the surgical treatment of FFP has yet to be defined. Therefore, the aim of this study was to conduct a systematic review of the current literature concerning studies that are comparing the performance of cement augmented versus non-augmented sacroiliac (SI) screws. METHODS: We conducted a systematic literature review from 01/01/2000 onwards. Inclusion criteria were randomized controlled studies, case series (n>3), biomechanical studies and reviews, comparing augmented and non-augmented SI screws. Only papers in German or English language were included. RESULTS: Out of 1247 initial hits, eleven studies met the inclusion criteria. Out of those, six were biomechanical studies and five were clinical case series. Most biomechanical studies showed cement augmented screws to have a greater mechanical stability, both regarding pull-out force and resistance to cyclic loading. The five case studies reported on a total of 98 patients with 122 screw fixations. Three cases of cement leakage into neuroforamina occurred, however, none of these patients showed clinical symptoms. CONCLUSION: In clinical case series, cement augmentation of SI screws appears to be a safe surgical technique without relevant complications and biomechanical studies demonstrate greater pull-out forces of augmented SI screws but no advantage in regard of cyclic loading. Hence, applicability of the mechanical testing results on the clinical situation are debatable. So far, there are neither retrospective nor randomized controlled studies comparing the performance of cemented and non-cemented SI screws in FFP. Therefore, the clinical benefit of SI screw cement augmentation is unclear and their use remains experimental.

Clinical efficacy of lead revisions during the test phase in sacral neuromodulation for fecal incontinence.

BACKGROUND: Success rates of up to 80% have been reported for the SNM screening period in the treatment of fecal incontinence (FI). Some patients who have an unsuccessful index implantation are successfully treated with SNM after a lead revision. There is a lack of studies comparing the outcomes of successful index implantations and successful lead revision. Therefore, the results of index implantations were compared with lead revisions in a single-center cohort. METHODS: Patients treated with SNM for FI between 2008 and 2016 were retrospectively reviewed. Patients with a successful index implantation were compared with patients who underwent lead revision after SNM screening. Primary outcome was a decrease in episodes of fecal incontinence of ≥ 50% documented by a 3-week bowel habit diary. RESULTS: Two hundred sixty-one patients (232 index group, 29 revision group) were eligible for SNM. Two hundred thirty-one patients (208 index group, 23 revision group) received permanent SNM. Follow-up was 68.8 months for the index group and 62.2 months for the revision group. The number of episodes of FI decreased from 20.6 (SD 19.3) to 3.4 (SD 4.2) in the index group and from 12.6 (SD 5.8) to 2.0 (SD 2.3) in the revision group. This effect was maintained up to 5 and 2 years in the index and revision group, respectively. Adverse events such as loss of efficacy which required surgical intervention did not differ between the two groups. CONCLUSION: Lead revision during the test phase is a valid option in patients with FI treated by SNM who suffer from loss of efficacy of the index electrode.