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.

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.

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.

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.

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.

First-in-human implantation of a mid-field powered neurostimulator at the sacral nerve: Results from an acute study.

INTRODUCTION: Commercially approved implantable systems for sacral neuromodulation require the implantation of a multipolar lead subcutaneously connected to an implantable pulse generator (IPG). Eliminating the need for an IPG would eliminate the need for tunneling of the lead, reduce procedure time, infection risk, and the need for IPG replacement. The objective was to demonstrate the feasibility of implanting the AHLeveeS System in the S3 Foramen to stimulate the S3 sacral nerve. MATERIALS AND METHODS: A first-in-human, prospective, single center, nonrandomized, acute feasibility clinical investigation at the Maastricht University Medical Center+. Patients with refractory overactive bladder underwent acute implantation of the AHLeveeS neurostimulator before the InterStim procedure. Outcome measurements included motor responses, procedural time and a scoring of the difficulty of the implant and explant procedure. Retrospectively, qualitative responses to the stimulation protocol were assessed by video motion analyses. Only descriptive statistics were used. RESULTS: During the stimulation a motor response to stimulation was seen in four of the five subjects. In all implantations the AHLeveeS was correctly placed. The median time for complete procedure was 24 minutes. The implant and explant procedures were successfully performed and no device or procedure related adverse events occurred. CONCLUSIONS: The results from this acute first-in-human study demonstrate the feasibility of implantation and acute stimulation of the sacral nerve with this mid-field powered system. Future clinical studies will focus on safety and efficacy of a chronically implanted device.

Repeatability of tools to assist in the follow up and troubleshooting of sacral neuromodulation patients using the sensory response.

PURPOSE: Sacral neuromodulation (SNM) is an established minimally invasive therapy for functional disorders of the pelvic organs in which electrodes are stimulated in proximity of the sacral spinal nerves. Reprogramming of the electrodes is regularly required and is based on the sensory response. This study assesses the repeatability of a pelvic chart and grading system to enable a more objective assessment of the sensory response upon electrode stimulation. MATERIAL AND METHODS: In 26 SNM patients, with OAB or NOUR, assessment of the sensory response was done using the sensory threshold (ST) and a pelvic chart with 1 cm2 coordinates, each coordinate corresponding with a dermatome and location of sensation (LoS). A grading system was developed based upon the ST and LoS. Repeatability of ST was assessed using a two-way mixed effects, absolute agreement, single rater/measurement intraclass correlation coefficient (ICC), and displayed using a correlation and Bland Altman plot. Repeatability of dermatomes, LoS, and grading system was assessed using kappa correlation coefficient. RESULTS: On average, 1.55 ± 0.85 coordinates were used to point out the area where the stimulation was perceived. The mean amount of coordinates between the area pointed at during the first and second measurement was 0.47 ± 0.74. ST showed excellent repeatability (ICC 0.93, 95%CI 0.90-0.94, P < 0.001). Dermatomes, LoS and grading system showed a substantial to almost perfect agreement (κ = 0.740-0.833, P < 0.001). CONCLUSIONS: The pelvic chart and grading system, using the sensory response upon electrode stimulation, are repeatable tools and can be used to assist in follow up and troubleshooting of SNM patients.

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.

Factors influencing MR changes associated with sacral injury after high-intensity focused ultrasound ablation of uterine fibroids.

PURPOSE: We investigated the risk factors influencing MR changes associated with sacral injury from ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation for uterine fibroids. METHODS: We retrospectively analyzed a total of 346 patients with symptomatic uterine fibroids who received USgHIFU ablation. All of the patients underwent contrast-enhanced magnetic resonance imaging (CE-MRI) before and after treatment. Injury to the sacrum was set as the dependent variable, while fibroid features and the treatment parameters were set as independent variables. These variables were used to assess respectively their correlation with sacral injury by using univariate and multivariate analyses. RESULTS: The results of univariate analysis revealed that the volume, distance from the fibroid to the skin, maximal diameter, distance from the fibroid to the sacrum, fibroid types, degree of enhancement, therapeutic dosimetry (TD), energy efficiency factor (EEF) and non-perfused volume (NPV) ratio manifested significant correlations with the sacral injury (p < .05). Multivariate analysis showed that the degree of enhancement, TD and EEF were independent risk factors for sacral injury (p < .05), while the distance from fibroid to sacrum and intramural or subserosal types were protective factors (p < .05). The incidence of sacral tail pain and leg pain showed a significant positive correlation with sacral injury (p < .05). CONCLUSION: As important affecting factors, the degree of enhancement, distance from fibroid to sacrum and fibroid types all possess significant correlations with MR changes associated with sacral injury.

Spinal Fusion Is Associated With Changes in Acetabular Orientation and Reductions in Pelvic Mobility.

BACKGROUND: The importance of spinopelvic motion and its influence on THA stability are well recognized but poorly defined. With dynamic motion, compensatory changes in spine and pelvic positions are required to keep the necessary balance between the axial skeleton and lower extremity to maintain an erect posture. Although prior studies have shown spinal fusions to be an independent risk factor for hip dislocations after primary THA, the direct impact of fusion levels on spinopelvic motion remains unknown. QUESTIONS/PURPOSES: The purposes of this study were (1) to determine if acetabular orientation changes with flexion and extension of the lumbar spine; (2) to determine if the amount of change is different in patients who have undergone spinal fusion at the L5-S1 level; and (3) to identify if the amount of change in acetabular motion is increased in patients who have undergone fusion at additional or other spinal levels. METHODS: We reviewed 100 flexion-extension spine films of patients older than 18 years of age with a history of back pain who had not undergone spinal or hip surgery and compared them with 50 flexion-extension spine films of patients who had undergone lumbar fusion at various levels. These radiographs were acquired between 2012 and 2017 and stored in our institutional radiology database. Only patients with flexion and extension films able to visualize the greater trochanter of the femur were included. For each film, measurements of acetabular version, acetabular version relative to the femoral shaft, lumbar lordosis angle, and sacral slope were digitally performed by two independent observers. Intra- and interrater variability was assessed using Lin's concordance correlation (Rho_c) ranging from 0.59 to 0.91. The change in acetabular version for each patient when going from spinal flexion to extension was compared between patients with no prior spinal or hip surgery and those with prior spinal fusions using a two-tailed t-test. RESULTS: Acetabular version changed -21° as the lumbar spine changed position from flexion to extension in patients without spine surgery (95% confidence interval [CI], -24° to -18°). Acetabular version changed 15° as the lumbar spine changed position from flexion to extension in patients who had undergone prior lumbar spine fusion at all levels (95% CI, -18° to -12°). There was a difference in the change in acetabular version between these two groups of -6° (95% CI, -11° to -1°; p = 0.01). In patients with prior L5-S1 fusion, the change in acetabular version was decreased when compared with patients without prior spine surgery. The change was -10° (95% CI, -15° to -6°), which is less than the change of acetabular version of -21° that we saw in patients without prior spinal fusion (p < 0.01). The difference between these groups was -10° (95% CI, -18° to -3°). Fusion levels above L5 that did not cross the L5-S1 joint did not have a difference in change in acetabular version when compared with patients without surgery with a mean difference of -4° (95% CI, -9° to 2°). CONCLUSIONS: Spinal fusion, specifically at the L5-S1 level, reduces pelvic mobility as the spine moves from flexion to extension. This reduction in motion can reduce the distance to impingement and place patients undergoing THA at risk for dislocation. Further research utilizing three-dimensional imaging modalities and motion analysis can further help define the best hip implant position in these patients. LEVEL OF EVIDENCE: Level III, prognostic study.

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.

[Advances in the study of anatomy and biomechanics of lumbosacral transitional vertebrae].

Lumbosacral transitional vertebrae (LSTV) is a common phenomena of developmental anomaly, which is characterized by anatomic variation and biomechanical changes. LSTV is often accompanied with low back pain, lumbar disc herniation, lumbar spinal stenosis, lumbar spondylolisthesis and other spinal diseases. The diagnosis of LSTV has a great significance for proper treatment process. Early imageological studies have limitations on distinguishing different types of LSTV from the aspect of morphological changes. This review focuses on recent studies of LSTV anatomy and variation, its influence in local biomechanics and spinal alignment, and its relationship with spinal diseases.

CT-based evaluation of volumetric bone density in fragility fractures of the pelvis-a matched case-control analysis.

This matched case-control study compared the computed tomography (CT)-based regional bone density of patients with fragility fractures of the sacrum to a control without fracture. Patients with a sacral fracture demonstrated a significantly lower regional bone density of the sacrum, the sacral bone density not being correlated with the BMD by DXA of the spine. INTRODUCTION: The aim of this study is to compare the computed tomography-based regional bone density measured by Hounsfield units (HUs) in patients with and without fragility fractures of the sacrum. METHODS: Patients aged ≥ 50 years with a fragility fracture of the sacrum were compared to patients of similar age and gender who had a fall from standing height without fracture (n = 46). A matched case-control analysis was conducted by retrospective chart review and assessment of areal bone mineral density by lumbar DXA and by volumetric regional HU measurements in uncalibrated CT scans of the sacrum. RESULTS: Patients with a sacral fracture (age 74 ± 11 years) showed a lower bone density in the body of S1 (HU 85 ± 22) when compared to the matched control group without fracture (age 73 ± 10 years, HU 125 ± 37, p < 0.001). The CT-based bone density of S1 did not correlate with the DXA values of the lumbar spine (r = 0.223, p = 0.136), and lumbar spine T-scores did not differ between the groups (- 2.0 ± 1.3 vs. - 1.9 ± 1.2, p = 0.786). All measurements are based on uncalibrated scans, and absolute HU values are restricted to scans made on Siemens SOMATOM Force or SOMATOM Edge scanners. CONCLUSIONS: Patients with fragility fractures of the sacrum demonstrated a lower regional volumetric bone density of the sacrum when compared to a cohort without a fracture. Local sacral volumetric bone density as measured by CT seems to be independent from the areal BMD as measured by DXA of the lumbar spine. LEVEL OF EVIDENCE: level III.

The efficacy of botulinum toxin A and sacral neuromodulation in the management of interstitial cystitis (IC)/bladder pain syndrome (BPS), what do we know? ICI-RS 2017 think thank, Bristol.

AIMS: This manuscript aims to address the evidence availale in the literature on the efficacy of Botulinum Toxin A (BoNT-A) and sacral neuromodulation (SNM) in patients suffering from Interstitial Cystitis (IC)/BPS and propose further research to identify mechanisms of action and establish the clinical efficacy of either therapy. METHODS: At the International Consultation on Incontinence-Research Society (ICI-RS) in 2017, a panel of Functional Urologists and Urogynaecologists participated in a Think Tank (TT) discussing the management of IC/BPS by BoNT-A and SNM, using available data from both PubMed and Medicine literature searches. RESULTS: The role of BoNT-A and SNM in the treatment of IC/BPS are discussed and mechanisms of actions are proposed. Despite the available randomized trial data on the effect of intravesical BoNT-A treatment on symptoms of IC/BPS, a consistent conclusion of a positive effect cannot be drawn at the moment, as the published studies are small and heterogeneous in design. There is substantive evidence for the positive effects of SNM on symptoms of IC/BPS patients however, during patient selection, it is important to distinguish the degree and the location of pain in order to tailor the best therapy to the right patients. CONCLUSIONS: Both intravesical BoNT-A treatment and SNM have been shown to have positive effects in patients with IC/BPS. However, firm conclusions cannot yet be drawn. Patient-reported outcomes and quality of life should be assessed in addition to urinary and pain symptoms. Since current treatments mainly focus on symptomatic relief, future research should also focus on clarifying the pathogenic mechanisms involved in IC/BPS.

Lumbar to sacral root rerouting to restore bladder function in a feline spinal cord injury model: Urodynamic and retrograde nerve tracing results from a pilot study.

AIMS: Lumbar to sacral rerouting surgery can potentially allow voiding via a skin-central nervous system-bladder reflex pathway. Here, we assessed if this surgery was effective in treating neurogenic bladder dysfunction/sphincter in felines. METHODS: Eight cats underwent spinal cord transection (SCT) at thoracic level 10/11. Unilateral L7 to S1 ventral root anastomosis was performed 1 month later in six cats. Two cats served as transection-only controls. Electrical and manual stimulation of L6-S1 dermatomes, and urodynamics were performed at 3, 5, 7, and 9/10 months post transection. At 9/10 months, cats were also evaluated by direct electrophysiological testing of anastomosed roots with urodynamics, then tissue collection and examination of the root anastomosis site and lumbosacral cord ventral horns for cells retrogradely labeled from tracer dye injected 2 weeks earlier into the bladder wall. RESULTS: At 9/10 months, four of six rerouted cats exhibited increased detrusor pressure provoked by cutaneous stimulation, one cat bilaterally. Two cats presented with a voiding stream after ipsilateral cutaneous stimulation at 7 and 9 months. All six rerouted animals showed regrowth of axons from the L7 ventral horn to the bladder, although some aberrant axonal regrowth was also observed. CONCLUSION: L7 to S1 ventral root rerouting below the level of SCT showed successful axonal regrowth to the bladder from the L7 spinal cord segment in all rerouted animals, and induced increased detrusor pressure response to cutaneous stimulation in a subset. This feasibility study paves the way for future animal studies for bladder reinnervation.

Biomechanical analysis of spino-pelvic postural configurations in spondylolysis subjected to various sport-related dynamic loading conditions.

PURPOSE: To study the risks of spondylolysis due to extrinsic loading conditions related to sports activities and intrinsic spino-pelvic postural parameters [pelvic incidence (PI) and sacral slope (SS)]. METHODS: A comprehensive osseo-disco-ligamentous L4-S1 finite element model was built for three cases with spondylolysis representing three different spino-pelvic angular configurations (SS = 32°, 47°, 59° and PI = 49°, 58°, 72°, respectively). After simulating the standing posture, 16 dynamic loading conditions were computationally tested for each configuration by combining four sport-related loads (compression, sagittal and lateral bending and axial torque). For each simulation, the Von Mises stress, L5-S1 facet contact force and resultant internal loads at the sacral endplate were computed. Significant effects were determined with an ANOVA. RESULTS: The maximal stress and volume of cancellous bone in the pars with stress higher than 75% of the ultimate stress were higher with 900 N simulated compression (2.2 MPa and 145 mm3) compared to only the body weight (1.36 MPa and 20.9 mm3) (p < 0.001). Combined compression with 10 Nm of flexion and an axial torque of 6 Nm generated the highest stress conditions (up to 2.7 MPa), and L5-S1 facet contact force (up to 430 N). The maximal stress was on average 17% higher for the case with the highest SS compared to the one with lowest SS for the 16 tested conditions (p = 0.0028). CONCLUSIONS: Combined flexion and axial rotation with compression generated the highest stress conditions related to risks of spondylolysis. The stress conditions intensify in patients with higher PI and SS. These slides can be retrieved under Electronic Supplementary Material.

The importance of proximal femoral angle on sagittal balance and quality of life in children and adolescents with high-grade lumbosacral spondylolisthesis.

PURPOSE: Previous studies did not specifically assess the influence of proximal femoral angle (PFA) on sagittal balance in high-grade spondylolisthesis (HGS). In addition, the relationship between PFA and quality of life (QOL) remains unknown. This study determines if increased PFA is associated with decreased QOL and sagittal balance in lumbosacral HGS. METHODS: This retrospective case-control study was performed on a cohort of 56 normal subjects and 42 patients with HGS. Initially, PFA was measured twice by 3 raters in a random subset of 30 subjects (15 normal and 15 HGS) to determine the intrarater and interrater reliability of the measurement technique. PFA was then measured for all subjects. For the 42 patients with HGS, QOL was assessed from the SRS-22 questionnaire, in addition to the evaluation of the spino-pelvic balance. RESULTS: The intrarater and interrater intraclass correlation coefficients for the measurement of PFA were, respectively, 0.951 and 0.958, suggesting excellent reliability. PFA was significantly higher in HGS patients (8.3° ± 6.7°; range - 5° to 24°) when compared to normal subjects (3.0° ± 3.1°; range - 6° to 10°). The PFA in HGS was 5.6° ± 5.6° (range - 5° to 18°), 8.9° ± 6.7° (range - 2° to 24°), and 14.0° ± 6.0° (range 7°-23°) in type 4 (balanced pelvis), type 5 (unbalanced pelvis/balanced spine), and type 6 (unbalanced pelvis and spine) subjects, respectively. There were, respectively, 23.5% (4/17), 26.3% (5/19), and 83.3% (5/6) of HGS patients with abnormal PFA ≥ 10° in type 4, type 5, and type 6 subgroups. Increased PFA in HGS patients was related with deteriorating self-image, pain, function and total SRS-22 score, as well as with increasing pelvic tilt and decreasing sacral slope. CONCLUSION: A PFA ≥ 10° is proposed as a criterion to define abnormal PFA. PFA was increased in HGS and increased along with deteriorating sagittal balance and QOL. PFA is a clinically relevant parameter of sagittal balance, and can be useful in the evaluation and management of patients with HGS.

Is L5-S1 motion segment different from the rest? A radiographic kinematic assessment of 72 patients with chronic low back pain.

PURPOSE: The relationship between biomechanical instability and degenerative changes in the lumbar spine in chronic low back pain (CLBP) patients remains controversial. The main objective of this retrospective radiographical study was to evaluate changes in kinematics at different lumbar levels (in particular the L5-S1 level) with progressive grades of disc degeneration and facet joint osteoarthritis in CLBP patients. METHODS: Using standing neutral and dynamic flexion/extension (Fx/Ex) radiographs of the lumbar spine, in vivo segmental kinematics at L1-L2 through L5-S1 were evaluated in 72 consecutive CLBP patients. Disc degeneration was quantified using changes in signal intensity and central disc height on mid-sagittal T2-weighted magnetic resonance (MR) scans. Additionally, the presence or absence of facet joint osteoarthritis was noted on T2-weighted axial MR scans. RESULTS: Disc degeneration and facet joint osteoarthritis occurred independent of each other at the L5-S1 level (p = 0.188), but an association was observed between the two at L4-L5 (p < 0.001) and L3-L4 (p < 0.05) levels. In the absence of facet joint osteoarthritis, the L5-S1 segment showed a greater range of motion (ROM) in Ex (3.3° ± 3.6°) and a smaller ROM in Fx (0.6° ± 4.2°) compared with the upper lumbar levels (p < 0.05), but the differences diminished in the presence of it. In the absence of facet joint osteoarthritis, no change in L5-S1 kinematics was observed with progressive disc degeneration, but in its presence, restabilisation of the L5-S1 segment was observed between mild and severe disc degeneration states. CONCLUSION: The L5-S1 motion segment exhibited unique degenerative and kinematic characteristics compared with the upper lumbar motion segments. Disc degeneration and facet joint osteoarthritis occurred independent of each other at the L5-S1 level, but not at the other lumbar levels. Severe disc degeneration in the presence of facet joint osteoarthritis biomechanically restabilised the L5-S1 motion segment.

Patterns and associations of structural and functional cutaneous responses during loading at heel and sacral skin in aged females: A reanalysis of clinical study data.

AIM OF THE STUDY: The aim of this study was to explore possible interrelationships and cutaneous response patterns at the heel and sacral skin due to prolonged loading. MATERIALS AND METHODS: Skin stiffness, elasticity, roughness and transepidermal water loss, stratum corneum hydration, erythema, and temperature of n = 20 aged females (mean age 69.9 years) were measured before and after 90 and 150 min loading in supine position. Delta values were calculated and correlated using Spearman's rho. Strengths and directions of associations and similar patterns were subsequently identified for the heel and sacrum areas. RESULTS: At the sacral area decreased stiffness (Uf) was associated with increased TEWL and there was a positive relationship between mean roughness (Rz) and erythema. At the heel there was a positive association between TEWL and decreasing stiffness (Uf). CONCLUSIONS: Our results indicate a dynamic interaction between skin changes during loading and different physiological response patterns for sacral and heel skin. There seems to be close association between transepidermal water loss and stiffness changes during loading.