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.

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.

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.

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.

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.

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.

[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.

Lumbar fusion involving the sacrum increases dislocation risk in primary total hip arthroplasty.

AIMS: Concurrent hip and spine pathologies can alter the biomechanics of spinopelvic mobility in primary total hip arthroplasty (THA). This study examines how differences in pelvic orientation of patients with spine fusions can increase the risk of dislocation risk after THA. PATIENTS AND METHODS: We identified 84 patients (97 THAs) between 1998 and 2015 who had undergone spinal fusion prior to primary THA. Patients were stratified into three groups depending on the length of lumbar fusion and whether or not the sacrum was involved. Mean age was 71 years (40 to 87) and 54 patients (56%) were female. The mean body mass index (BMI) was 30 kg/m2 (19 to 45). Mean follow-up was six years (2 to 17). Patients were 1:2 matched to patients with primary THAs without spine fusion. Hazard ratios (HR) were calculated. RESULTS: Dislocation in the fusion group was 5.2% at one year versus 1.7% in controls but this did not reach statistical significance (HR 1.9; p = 0.33). Compared with controls, there was no significant difference in rate of dislocation in patients without a sacral fusion. When the sacrum was involved, the rate of dislocation was significantly higher than in controls (HR 4.5; p = 0.03), with a trend to more dislocations in longer lumbosacral fusions. Patient demographics and surgical characteristics of THA (i.e. surgical approach and femoral head diameter) did not significantly impact risk of dislocation (p > 0.05). Significant radiological differences were measured in mean anterior pelvic tilt between the one-level lumbar fusion group (22°), the multiple-level fusion group (27°), and the sacral fusion group (32°; p < 0.01). Ten-year survival was 93% in the fusion group and 95% in controls (HR 1.2; p = 0.8). CONCLUSION: Lumbosacral spinal fusions prior to THA increase the risk of dislocation within the first six months. Fusions involving the sacrum with multiple levels of lumbar involvement notably increased the risk of postoperative dislocation compared with a control group and other lumbar fusions. Surgeons should take care with component positioning and may consider higher stability implants in this high-risk cohort.

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.

S1 Pedicle Subtraction Osteotomy for Fixed Sagittal Imbalance and Lumbosacral Kyphosis.

S1 pedicle subtraction osteotomies (PSOs) are indicated in patients with fixed, high-grade L5-S1 spondylolisthesis or kyphosis secondary to a sacral fracture, who present with severe sagittal imbalance. Unlike lumbar PSOs, sacral osteotomies are rare, and there is a paucity of literature outlining techniques. Here, we present the indications, planning, technique, and outcomes for S1 PSOs.

Risk Factors for Sacral Insufficiency Fractures in Cervical Cancer After Whole Pelvic Radiation Therapy.

AIM: To evaluate the incidence and risk factors of sacral insufficiency fractures (SIFs), particularly dose-volume histogram (DVH) parameters, in patients with cervical cancer after whole pelvic radiation therapy (WPRT). PATIENTS AND METHODS: The medical records of 61 patients with cervical cancer who underwent WPRT were retrospectively reviewed. The cumulative incidence of SIF, as well as the risk factors that could affect its incidence were assessed. RESULTS: Of the 61 patients, 11 (18%) were diagnosed with SIF, as revealed by computed tomography. Multivariate analysis revealed that abnormal body mass index (BMI) (more than 25 kg/m2 or below 18 kg/m2) and administration of five or more chemotherapy cycles were independently associated with SIF. A slight difference was observed in the D50% (the administered dose covering half of the sacrum) between patients with and those without SIF (p=0.052). CONCLUSION: Thus, the D50% of the sacrum should be particularly considered in patients with abnormal BMI and five or more cycles of chemotherapy.

S-1 alar/iliac screw technique for spinopelvic fixation.

Spinopelvic fixation provides an important anchor for long fusions in spinal deformity surgery, and it is also used in the treatment of other spine pathologies. Iliac screws are known to sometimes require reoperation due to pain resulting from hardware prominence and skin injury. S-2 alar/iliac (S2AI) screws do not often require removal, but they may provide inadequate fixation in select cases. In this paper the authors describe a technique for S-1 alar/iliac screws that may be used independently or as a supplement to S2AI screws. A preliminary biomechanical analysis and 2 clinical case examples are also provided.

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.

Concomitant conus medullaris arteriovenous shunts and sacral dural arteriovenous fistulas: pathophysiological links related to the venous drainage of the lesions in a series of five cases.

BACKGROUND: Spinal cord arteriovenous shunts (scAVSs) are a group of lesions located in the spinal cord itself or in the surrounding structures. The most common scAVSs are spinal dural arteriovenous fistulas (sDAVFs), which are acquired lesions. The pathogenesis of sDAVFs involves thrombosis and venous hypertension as trigger factors. Intradural scAVSs such as spinal cord arteriovenous nidus type malformations (AVMs) and pial arteriovenous fistulas are less common than sDAVFs and are considered to have a so-called 'congenital' origin. The association between different concomitant scAVSs is very rare and the association of sDAVFs with intradural scAVSs has been described in only a few case reports. METHODS: We describe a case series of five patients presenting with a conus medullaris AVS associated with a lower lumbar or sacral DAVF. RESULTS: Three of our patients were <30 years old at presentation. In four of these five cases the intradural scAVS drained caudally, engorging the epidural plexus in the same location as the sDAVF. In only one case, who presented with thrombosis of the drainage of the main compartment of a conus medullaris pial AVF, was the location of the DAVF opposite to the location of the residual drainage. CONCLUSION: We discuss the pathophysiological link between scAVS and sDAVF on the basis of the rarity of the DAVF, the uncommon association between scAVS and sDAVF, the presence of sDAVF in young patients, and the venous hypertension created by the venous drainage towards the sacral area responsible for angiogenesis creating the dural shunt.

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.

Good functional outcome in patients suffering fragility fractures of the pelvis treated with percutaneous screw stabilisation: Assessment of complications and factors influencing failure.

BACKGROUND: Low energy pelvic ring fractures in the elderly have traditionally been treated conservatively, a treatment with potential long-term complications and loss of self-independence. Percutaneous screw stabilisation of the posterior pelvic ring is a new treatment modality that enables immediate mobilisation. The aim of this study was to assess the functional outcome after sacroiliac stabilisation in the elderly. METHODS: All elderly patients with a surgically stabilised low energy pelvic fracture between 2010 and 2015 were included. In 2016 a radiographic follow up and functional test was performed at least one year postoperative. RESULTS: The 50 operated patients had a mean age of 79 years and a one-year mortality of 10% (5/50). Only six patients lost independency after the pelvic fracture and moved to nursing home. The mean Timed Up and Go test was 16s at follow-up. The operation of the posterior pelvic ring averaged 63min with a radiation equal to a diagnostic pelvic CT. One intra-foraminally placed screw was immediately removed and 9 patients were later re-operated on due to symptomatic loosening of one or more screws. No loosening of screws was seen in 11 patients where both S1 and S2 were stabilised and out of 23 trans-sacral screws (crossing both sacroiliac joints) only two loosened. DISCUSSION: CT guided stabilisation of the posterior pelvis is safe and most patients resumed good function and independent living. The risk of a revision operation was 20%, but trans-sacral screw stabilisation in both S1 and S2 could reduce the risk of implant loosening.

Longitudinal Midline Sacral Split Fracture - A Rare Entity.

Fractures involving the central canal of the sacrum are rare injuries and can be transverse or longitudinal. Transverse fractures are by far common and associated with high incidence of neurological injuries. On the contrary, longitudinal midline split fracture is an extremely rare injury with minimal or no neurological injury. They are always associated with anterior pelvic ring fracture and are vertically stable needing only fixation of the anterior pelvic injury. Plating of the anterior pelvic ring in two planes would be beneficial than single plate to prevent gradual loss of reduction.

Evaluation of changes in lumbar neuroforaminal dimensions in symptomatic young adults using positional MRI.

PURPOSE: To investigate the changes of lumbar neural foramina size during dynamic motion using positional MRI. METHODS: Two hundred and fifty neural foramina from 50 patients were analyzed. Lumbar foraminal height, width, and area parameters from L1 to S1 were evaluated for changes in extension, neutral, and flexion positions on T2 parasagittal positional MRI images, and were correlated to lumbar angular motion. One-way analysis of variance (ANOVA) and post hoc analysis were used to examine the differences between levels and positions. RESULTS: Compared to the neutral position, almost all lumbar foraminal parameters (height, width at inferior level, and area) increased in flexion and decreased in extension at all levels, except for L5-S1 foraminal width at superior and middle levels. The foraminal height and area in all lumbar segments except L5-S1 increased as the lumbar angular motion changed from extension to flexion in <40° group. The foraminal width increased significantly at L3-4 and L4-5 among all groups. CONCLUSION: Lumbar foraminal dimensions increased in flexion compared to neutral and extension positions. Lumbar angular motion contributed to the changes of foraminal height and area at most of the segments, while it affected foraminal width only at L3-4 and L4-5. This information can be useful in the understanding of patient symptoms and the correlation with the imaging studies with dynamic foraminal stenosis. Furthermore, data from our study may help with patient positioning for foraminal injections or endoscopic surgery.

What Are the Conditional Survival and Functional Outcomes After Surgical Treatment of 115 Patients With Sacral Chordoma?

BACKGROUND: Conditional survival is a measure of prognosis for patients who have already survived for a specific period of time; however, data on conditional survival after sacrectomy in patients with sacral chordoma are lacking. In addition, because sacral tumors are rare and heterogeneous, classifying them in a way that allows physicians to predict functional outcomes after sacrectomy remains a challenge. QUESTIONS/PURPOSES: (1) What is the overall survival and disease-free survival in patients treated by sacrectomy for chordoma? (2) What is the conditional survival probability and how do prognostic factors change over time in patients undergoing surgical resection for sacral chordoma? (3) What is the local recurrence rate after surgery, how was it treated, and what factors impact on local recurrence? (4) What is the postoperative motor, sensory, bowel, and bladder function by level of resection as determined by using a newly designed scoring method? METHODS: Between 2003 and 2012, our center treated 122 patients surgically for sacral chordoma. Of those, two died and five were lost before a minimum followup of 1 year was achieved, leaving 115 patients available for analysis in this retrospective study at a mean of 4.9 years (range, 1.3-10.8 years). Basically, single posterior or combined approaches were chosen based on the most cephalad extent of the tumor and resection level was normally at half or one sacral vertebrae above the tumor. The 5-year conditional survival rate was calculated based on Kaplan-Meier survival analysis. The effect of prognostic factors on conditional survival was also explored. A newly designed score method was proposed and adopted in the current study to critically evaluate the functional outcome after resection of the sacrum. Inter- and intraobserver reliability was tested by a preliminary study using kappa statistics and Spearman rank correlation coefficients. Significant interobserver (p < 0.01) and intraobserver agreement (κ > 0.75) were found in nine items between each observer. RESULTS: The estimated 5-year overall survival rate was 81% (95% confidence interval [CI], 72%-90%) at diagnosis. The 5-year disease-free survival rate was 52% (95% CI, 43%-63%). The 5-year conditional overall survival decreased with each additional year in the first 4 years (81% at diagnosis versus 60% at the fourth year, p < 0.0001) and increased slightly in the fifth year. Patients with adequate surgical margins displayed a higher 5-year survival than those with an inadequate margin (86% [95% CI, 76%-95%] versus 67% [95% CI, 48%-85%], p = 0.01) at diagnosis. Conditional survival estimates for patients who received operations elsewhere were lower than that of newly diagnosed patients treated by us at diagnosis (64% [95% CI, 46%-83%] versus 90% [95% CI, 82%-99%], p = 0.012), but with the numbers we had, we could not detect a difference in conditional survival between those treated elsewhere first compared with those initially treated by us at 5 years. The proposed score system for function evaluation was able to distinguish different levels of resection. The overall functional results for the preservation of bilateral S1, S2, and S3 were 40 ± 8%, 60 ± 12%, and 82 ± 11%, respectively. Patients who had preservation of only one S3 nerve root had more severe incontinence (1.99 ± 0.79 versus 2.60 ± 0.63, p = 0.01) and more sensory loss (1.88 ± 0.82 versus 2.31 ± 0.59, p = 0.02) than those patients with preservation of bilateral S3 nerve roots. CONCLUSIONS: The 5-year conditional survival for sacral chordoma decreased with each additional year and began to improve after the fourth year. In addition, the effect of the surgical margin and influence of previous surgery on conditional survival were not linear over time. The level of nerve root resections corresponded with the overall function scores according to the proposed scoring method. This information and scoring system should be valuable in discussing outcomes of sacrectomy in patients with chordoma who are considering this operation and serve as the basis for further study. LEVEL OF EVIDENCE: Level III, therapeutic study.