Current Concepts in the Treatment of Giant Cell Tumor of Bone: An Update

Curettage is recommended for the treatment of Campanacci stages 1-2 giant cell tumor of bone (GCTB) in the extremities, pelvis, sacrum, and spine, without preoperative denosumab treatment. In the distal femur, bone chips and plate fixation are utilized to reduce damage to the subchondral bone and prevent pathological fracture, respectively. For local recurrence, re-curettage may be utilized when feasible. En bloc resection is an option for very aggressive Campanacci stage 3 GCTB in the extremities, pelvis, sacrum, and spine, combined with 1-3 doses of preoperative denosumab treatment. Denosumab monotherapy once every 3 months is currently the standard strategy for inoperable patients and those with metastatic GCTB. However, in case of tumor growth, a possible malignant transformation should be considered. Zoledronic acid appears to be as effective as denosumab; nevertheless, it is a more cost-effective option. Therefore, zoledronic acid may be an alternative treatment option, particularly in developing countries. Surgery is the mainstay treatment for malignant GCTB.

Mean S1 inlet and outlet view angles are not safe for all individuals according to three-dimensional tomographic measurements

Although there are many studies evaluating optimal inlet and outlet angles required for the correct placement of S1 iliosacral screws, there is no study evaluating reliability and feasibility of these angles for all individuals on three-dimensional (3D) anatomical models. A total of 100 women and 100 men were selected randomly. A vertical line was created according to long axis of the tomography device on which patient was lying in supine position. The automatized best-fit planes were created on superior and inferior endplates, anterior cortex including notch region and posterior cortex of first sacral vertebrae using 3D imaging software to measure mean inlet and outlet angles. We observed no statistically significant difference between gender groups in terms of inlet and outlet angles. Mean inlet view is obtained for anterior cortex of S1 in 22.5 ± 9.5° and for posterior cortex in 46.5 ± 9.3°. Mean fluoroscopic view angle of S1 for superior outlet is 40.3 ± 7.6 and for inferior outlet is 46.9 ± 8.8. Mean anterior and posterior S1 inlet view angles do not accurately visualize anterior cortex of 74 (37%) and posterior cortex of 66 (33%) individuals. Mean superior and inferior S1 outlet view angles do not accurately visualize superior endplate of 74 (37%) and inferior endplate of 56 (28%) individuals. Due to individual alterations of spatial position of sacrum, mean inlet and outlet view angles of S1 are not sufficient to visualize the iliosacral screws under fluoroscopy in many individuals.

Long-Term Follow-Up after Iliosacral Screw Fixation of Unstable Pelvic Ring Fractures

(1) Background: High-energy injuries of the pelvic ring are rare. The wide application of iliosacral screw fixation of the posterior pelvic ring is relatively new. The aim of the present study was to evaluate the long-term quality of life. (2) Methods: All patients treated with an iliosacral screw for a posterior pelvic ring stabilization after high-energy trauma at a level 1 trauma center between 2005 and 2015 were included. Pelvic ring injuries were classified according to the Tile classification adapted by AO/ASIF. The clinical evaluation included the patient-oriented questionnaires surveys of the Majeed Score, Iowa Pelvic Score (IPS), Work Ability Index (WAI), SF-36, EQ5D-5L. (3) Results: A total of 84 patients were included with a median follow-up of 130.1 months (IQR 95.0-162.0 months). The median ISS was 22.5 (IQR 16.0-29.0), mean Majeed Score 83.32 (SD ± 19.26), IPS 77.88 (SD ± 13.96), WAI 32.71 (SD ± 11.31), SF-36 PF 71.25 (SD ± 29.61) and EQ5D-5L 0.83 (SD ± 0.21). There was a notably difference between uni- and bilateral pelvic fractures (p = 0.033) as well as a correlation with the ISS (p = 0.043) with inferior functional outcome measured by IPS. (4) Conclusions: Long-term follow-up of iliosacral screw fixation of unstable pelvic ring fractures showed a good quality of life and functional outcome with equal EQ5D-5L results and inferior SF-36 physical functioning compared to the German population.

Forced Straightening of the Back Does Not Improve Body Shape

BACKGROUND

Sitting for a long time causes various postural problems, such as slump sitting. It has been reported that employing a corrected sitting position while lifting the sternum is effective in improving this form of posture. We investigated how a corrected sitting posture with the lifting of the sternum is different from a forced position that is applied through the command and passive positions.

MATERIALS AND METHODS

The postural angle of 270 subjects aged 19-23 years was measured in the passive, forced, and corrected positions using a Saunders inclinometer and a Formetric 4D system.

RESULTS

As a result, the corrected position had a small range (min-max) at all angles, but the forced position and passive position had a large range (min-max). The lumbar lordosis angle in the corrected position showed positive values throughout its range (min-max), while the other groups showed negative values, which indicates the kyphotic position of the lumbar section. In addition, the percentage error in the corrected position was small, but it presented high values in the other groups. When comparing the average angles between the groups, there were substantial changes observed between the corrected position and the other groups. It was found that the corrected position with the sternum lifted, which is applied to improve slump sitting in the clinical environment, exhibited an angle that differed from that of the forced position and the passive position.

CONCLUSIONS

Our results suggest that a forced position on the command "scapular retraction" does not meet the clinical assumptions of posture correction, in contrast to the corrected position with the lifting of the sternum for the improvement of slump sitting. The accurate correction of the position of the sternum and sacrum improves the position of the spine in the sagittal plane, enabling physiological values for the kyphosis and lordosis angle parameters to be obtained. This approach combines the ease of execution and precision of the effect. The fact that this method does not require complex tools to accurately correct the body encourages the implementation of this solution in clinical practice.

A Case of Symptomatic Multiple Tarlov Cysts Treated with Microsurgical Wrapping Technique -Efficacy and Limitation of Surgical Procedure

Tarlov cysts (TCs) rarely cause clinical symptoms, such as leg pain, buttock pain, and bladder/bowel dysfunction. Surgery is considered when these symptoms persist despite medical treatments. Among several surgical procedures, microsurgical wrapping (MSW) is a relatively novel, simple technique with few complications, including cerebrospinal fluid leakage. Herein, we report a case of multiple TCs treated with MSW and present the mechanism of symptoms generated by TC and the procedure's limitations. A 58-year-old man complained of severe right leg and buttock pain for 3 months and was admitted to our hospital. His symptoms aggravated with sitting and standing and improved with the prone position. Spinal magnetic resonance imaging (MRI) demonstrated multiple sacral cysts containing intense cerebrospinal fluid. The cysts connect to the right S3 and S4 nerve roots. He was treated conservatively with medications; however, his symptoms were not improved. Therefore, MSW was performed for TCs connected to the S3 and S4 roots. The postoperative course was uneventful, and cerebrospinal fluid leakage did not occur. MRI performed 1 year after the operation demonstrated no recurrence of the TCs, and his leg pain was completely relieved; however, the buttock pain remained. MSW for TCs is effective for symptoms of adjacent nerve root compression; however, repairing the damaged nerve root in TCs is sometimes difficult. This may be a limitation of present surgical interventions because these symptoms may be difficult to treat even with other interventions.

Outcomes of Lumbosacral Fixation in Patients with Suicidal Jumper's Fractures: A Retrospective Study from a Single Center in Turkey

BACKGROUND Suicide attempts that involve jumping from a great height may not be fatal but can result in lumbosacral facture-dislocations. This retrospective study aimed to present the experience from a single center in Turkey of 21 patients with lumbosacral facture-dislocations, or suicidal jumper fractures, treated with lumbosacral fixation between 2015 and 2022. MATERIAL AND METHODS The study included 21 patients. The diagnosis was established through X-ray and computed tomography (CT) examinations. Neurological damage was assessed using the Gibbons score. Among the patients, 2 were classified as Roy-Camille type 1, 12 as Roy-Camille type 2, and 7 as Roy-Camille type 3. Morphologically, 8 patients had H-type fractures, 7 had T-type fractures, and 6 had U-type fractures. Bilateral spinopelvic fixation was performed. Functional outcomes were evaluated using the Majeed score. RESULTS The average Injury Severity Score (ISS) was 31.6±12.2. The mean duration of surgery was 123.6±44.9 minutes. According to the Majeed score, excellent results were observed in 8 individuals (40%), good results in 5 individuals (25%), fair results in 5 individuals (25%), and poor results in 2 individuals (10%). Out of 18 patients with neurological deficits, 14 showed improvement after surgery, while 4 continued to experience deficits. CONCLUSIONS The findings from this study highlight the importance of obtaining a clear history of the cause of lumbosacral facture-dislocation, as attempted suicide by jumping from a height can cause specific types of injury to the lumbar spine and sacrum that require rapid diagnosis and management to reduce the incidence of permanent paraplegia.

Effects of vibration-based biofeedback on multifidus muscle activity and pelvic tilt angle in subjects with hip flexion limitation

BACKGROUND

Sedentary work may lead to low back pain. In particular, a slumped sitting position may exacerbate low back pain because of tissue damage caused by excessive lumbar flexion and posterior pelvic tilting. Subjects with low back pain may have excessive changes in the lumbopelvic posture and back muscle activity in the sitting position.

OBJECTIVE

The purpose of this study was to compare the effects of vibration-based biofeedback using a motion sensor belt and no biofeedback on multifidus (MF) muscle activity and pelvic tilt angle during typing.

METHODS

Thirty subjects with low back pain accompanied by hip flexion limitation (15 each in the biofeedback and non-biofeedback groups) were enrolled. Electromyography was used to investigate MF muscle activity before and after typing for 30 min. Pelvic tilt was measured after typing in a sitting position for 30 min. Independent t-tests were used to compare MF muscle activity, and pelvic and second sacrum tilt angles, between the biofeedback and non-biofeedback groups.

RESULTS

After typing for 30 min, changes in MF muscle activity (11.45% and -7.19% for the biofeedback and nonbiofeedback groups, respectively) and pelvic and second sacrum tilt angles (3.15∘ and 4.12∘ for the biofeedback group and -11.05∘ and -18.16∘ for the non-biofeedback group, respectively) were significantly smaller in the biofeedback than non-biofeedback group (p< 0.05).

CONCLUSION

Vibration-based biofeedback minimizes the reduction in MF muscle activity and changes in pelvic and second sacrum tilt angles during typing in individuals with low back pain accompanied by hip flexion limitation.

Techniques for restoring optimal spinal biomechanics to alleviate symptoms in Bertolotti syndrome: illustrative case

BACKGROUND

Lumbosacral transitional vertebrae (LSTVs) are congenital anomalies that occur in the spinal segments of L5-S1. These vertebrae result from sacralization of the lowermost lumbar segment or lumbarization of the uppermost sacral segment. When the lowest lumbar vertebra fuses or forms a false joint with the sacrum (pseudoarticulation), it can cause pain and manifest clinically as Bertolotti syndrome.

OBSERVATIONS

A 36-year-old female presented with severe right-sided low-back pain. Computed tomography was unremarkable except for a right-sided Castellvi type IIA LSTV. The pain proved refractory to physical therapy and lumbar epidural spinal injections, but targeted steroid and bupivacaine injection of the pseudoarticulation led to 2 weeks of complete pain relief. She subsequently underwent minimally invasive resection of the pseudoarticulation, with immediate improvement in her low-back pain. The patient continued to be pain free at the 3-year follow-up.

LESSONS

LSTVs alter the biomechanics of the lumbosacral spine, which can lead to medically refractory mechanical pain requiring surgical intervention. Select patients with Bertolotti syndrome can benefit from operative management, including resection, fusion, or decompression of the pathologic joint.

Operative Treatment of Tarlov Cysts - Outcomes and Predictors of Improvement after Surgery: A Series of 97 Consecutive Patients and a Systematic Review of Literature

STUDY DESIGN

A register-based retrospective series and a systematic review of literature.

OBJECTIVES

Tarlov cysts are meningeal cysts typically found in the sacral region. They have a dualistic nature ranging from an incidental finding to a symptomatic pathology. There are no established treatment protocols and predictors of operative outcome. Therefore, we aimed to study the outcome of surgical treatment for Tarlov cysts and to characterize patient-, and treatment-related factors predicting outcomes.

METHODS

A systematic review of previous literature was performed and a retrospective cohort of all patients operated on for Tarlov cysts at BLINDED between 1995 and 2020 was collected. Patient records were evaluated along with radiological images.

RESULTS

Ninety-seven consecutive patients were identified with follow-up data available for 96. Improvement of symptoms after surgery was observed in 76.0% of patients (excellent or good patient-reported outcome) and the complication rate was 17.5%. Sacral or lower back pain as a preoperative symptom was associated with improvement after surgery (P = .007), whereas previous lower back surgery was more common in patients who did not benefit from surgery (P = .034). No independent predictors of outcome were identified in a regression analysis.

CONCLUSIONS

This is the second-largest study on the treatment of Tarlov cysts ever published. Operative treatment in a selected patient population will likely produce improvement in the symptoms when balanced with the complication rate and profile of surgery. Preoperative lower back or sacral pain is a potential indicator for improvement after surgery.

Unobstructed orthopaedic surgical robot assisted percutaneous iliosacral screw fixation of sacral brittle fractures

Pelvic fractures mostly result from high-energy injuries in life; the longitudinal fracture of the sacrum is the most common type of sacrum fracture. This study was designed to evaluate the accuracy, safety, and efficacy of percutaneous sacroiliac joint screw placement in the treatment of longitudinal sacrum fractures with the assistance of unobstructed orthopaedic surgery robots. According to different surgical methods, 32 patients were divided into robot group and free hand group, with 16 patients in each group. The operation time, intra-operative blood loss, intra-operative fluoroscopy times, screw placement angle deviation were collected. There were statistically significant differences in terms of angle deviation of screw placement (1.96 ± 0.75° vs. 2.87 ± 1.03°; p = 0.0145), deviation of the guide needle (1.92 ± 0.93 mm vs. 2.91 ± 1.22 mm; p = 0.0209), intra-operative fluoroscopy time (7.25 ± 1.72 s vs. 20.93 ± 5.64 s; p = 0.0000), insertion time of each sacroiliac joint screw (14.72 ± 2.66 min vs. 29.21 ± 5.18 min; p = 0.0000). There was no statistically significant difference in terms of blood loss (100.21 ± 7.37 mL vs. 102.52 ± 8.15 mL; p = 0.4136). These results suggest that orthopaedic surgery robot for the treatment of longitudinal sacrum fracture is safer and provides less irradiation than the traditional freehand methods.

Non-invasive assessment of sacroiliac joint and lumbar spine positioning in different unilateral sitting postures

BACKGROUND

Sacroiliac joint (SIJ) motion has been documented using invasive and noninvasive kinematic techniques. No study has explored SIJ angular positions in functional postures using noninvasive techniques. The purpose of this study was to quantify SIJ positioning among different seated postures in a healthy population.

METHODS

Twelve female and 11 male healthy young participants participated. Left and right anterior and posterior superior iliac spines were manually digitized during standing, neutral sitting and four different seated postures. Rigid bodies recorded the kinematics of the lumbar spine. Angles calculated included transverse sacroiliac angle, innominate sagittal angle, sacral tilt, lumbar flexion-extension, lumbar lateral bend and lumbar axial twist.

FINDINGS

The observed range of angular positions was approximately 3 to 4 degrees across the SIJ-related angles. The main effect of seated posture was observed for all angles measured. The main effect of sex was observed for all angles except lumbar lateral bending. Females consistently experienced more posterior sacral tilt than males. Interaction effects between sex and posture were only observed at the right-transverse sacroiliac angle and sacral tilt. Previous sitting posture affected the subsequent neutral sitting posture for the right-transverse sacroiliac angle and lumbar spine angle.

INTERPRETATION

SIJ angular position differences among the seated postures were similar in magnitude to motions previously reported in participants undergoing prone passive hip abduction and external rotation. Sex differences, including greater sacral posterior tilt observed in females, likely reflect underlying morphological and physiological differences. Future studies should explore SIJ positioning during functional tasks in pathological populations to help elucidate the underlying causes of SIJ pain and inform treatment strategies.

External Fixation for Fracture Stabilization of the Sacrum in 15 Dogs

This study aimed to evaluate the feasibility, complications, and outcomes of external fixation (EF) for the treatment of sacral fractures in dogs, either as a primary fixation system or as a complementary technique. A total of 15 dogs with sacral fractures were surgically treated using different EF configurations, either as primary or secondary stabilization. The results were evaluated for the extent of fracture reduction, stability during treatment, complications, and bone healing. In most cases, the outcomes were excellent in terms of bone healing, neurological conditions, and pain assessment. The mean bone healing time was 9.45 ± 5.66 weeks. One (6.66%) patient presented a complication due to the technique. In conclusion, the use of EF should be considered for the stabilization of sacral fractures because of its minimal invasiveness, stability, and ease of application.

The Influence of Regional Differences on the Reliability of the AO Spine Sacral Injury Classification System

STUDY DESIGN

Global cross-sectional survey.

OBJECTIVE

To explore the influence of geographic region on the AO Spine Sacral Classification System.

METHODS

A total of 158 AO Spine and AO Trauma members from 6 AO world regions (Africa, Asia, Europe, Latin and South America, Middle East, and North America) participated in a live webinar to assess the reliability, reproducibility, and accuracy of classifying sacral fractures using the AO Spine Sacral Classification System. This evaluation was performed with 26 cases presented in randomized order on 2 occasions 3 weeks apart.

RESULTS

A total of 8320 case assessments were performed. All regions demonstrated excellent intraobserver reproducibility for fracture morphology. Respondents from Europe (k = .80) and North America (k = .86) achieved excellent reproducibility for fracture subtype while respondents from all other regions displayed substantial reproducibility. All regions demonstrated at minimum substantial interobserver reliability for fracture morphology and subtype. Each region demonstrated >90% accuracy in classifying fracture morphology and >80% accuracy in fracture subtype compared to the gold standard. Type C morphology (p2 = .0000) and A3 (p1 = .0280), B2 (p1 = .0015), C0 (p1 = .0085), and C2 (p1 =.0016, p2 =.0000) subtypes showed significant regional disparity in classification accuracy (p1 = Assessment 1, p2 = Assessment 2). Respondents from Asia (except in A3) and the combined group of North, Latin, and South America had accuracy percentages below the combined mean, whereas respondents from Europe consistently scored above the mean.

CONCLUSIONS

In a global validation study of the AO Spine Sacral Classification System, substantial reliability of both fracture morphology and subtype classification was found across all geographic regions.

Sacral Tarlov cysts: Neurophysiology abnormalities and correlation with pelvic sensory and visceral symptoms

BACKGROUND AND PURPOSE

Recent studies suggest a possible association between Tarlov cysts (TCs), usually considered as incidental radiological findings, and neurological symptoms such as pain, numbness and urogenital complaints. The aim was to explore the relationship between TCs and sacral nerve root functions using pelvic neurophysiology tests, and to correlate changes with clinical symptoms and magnetic resonance imaging (MRI) findings.

METHODS

Consecutive patients with sacral TCs, referred for pelvic neurophysiology testing and presenting with at least one symptom related to the pelvic area, participated in a cross-sectional review of symptoms using validated questionnaires. Findings of pelvic neurophysiology (pudendal sensory evoked potentials, sacral dermatomal sensory evoked potentials, external anal sphincter electromyography) and urodynamics testing were collected retrospectively. The relationship between neurophysiology, MRI findings and patients' symptoms was assessed using Fisher and ANOVA tests.

RESULTS

Sixty-five females were included (mean age 51.2 ± 12.1 years). The commonest symptom was pain (92%). Urinary (91%), bowel (71%) and sexual (80%) symptoms were also frequently reported. Thirty-seven patients (57%) had abnormal neurophysiology findings reflecting sacral root dysfunction. No association was seen between MRI findings (size, location of the cysts, severity of compression) and neurophysiology. A negative association was observed between neurophysiology abnormalities and occurrence of urgency urinary incontinence (p = 0.03), detrusor overactivity (p < 0.01) and stress urinary incontinence (p = 0.04); however, there was no association with voiding difficulties.

CONCLUSIONS

Contrary to current understanding, TCs are associated with injury to the sacral somatic innervation in the majority of patients with presumed symptomatic cysts. However, urinary incontinence is unlikely to be related to TC-induced nerve damage.

The Impact of Virtual Interactive Three-Dimensional Model in the Conceptualization of the Anatomy of the Sacrum: A Randomized Controlled Trial

Introduction Virtual interactive three-dimensional model (VI3DM) is an emerging technology with promising futures in medical education. It allows learners to view and interact with the three-dimensional (3D) object in an isolated virtual environment, as well as on screen-based platforms. This technology seems more helpful in understanding the learning objectives that demand high cognitive and visuospatial skills. The sacrum, part of the posterior wall of the bony pelvis, is a structure of interest to medical professionals and forensic experts. Understanding the anatomy and relations of the sacrum demands good spatial understanding. Hypothetically, virtual 3D models should help in learning the anatomy of the sacrum along with its relations and attachments. This study was conducted to find out the effect of low-cost digital 3D models on the anatomical knowledge of the study. Aims and objectives The goal of the work was to identify the role of virtual 3D models in the conceptualization of the anatomy of the sacrum. The study's objectives were to identify the impact of virtual 3D models on students' knowledge of the external features, relations, attachments, and joints formed by the sacrum. Material and methods Two hundred first-year medical students (168 males and 32 females) who participated in the study after providing informed consent were divided into two equal groups, a control group (n=100) and an experimental group (n=100), after matching the age, gender, and anatomical knowledge of the sacrum. We used two-dimensional (2D) images and virtual interactive 3D models of the sacrum as control and intervention, respectively, in this randomized controlled study. We conducted a post-test quiz after the 30-minute session of self-directed learning. Results The mean difference between the post-test score and the pre-test score of the experimental group (4.1±1.6 ) was significantly higher than the difference between the post-test and pre-test scores of the control group (2.5±1.2). The virtual interactive 3D model of the sacrum was significantly effective in the conceptualization of the sacrum anatomy. Conclusion A virtual interactive 3D model is an effective tool to conceptualize the anatomy of the sacrum and can be explored for its use in further complex anatomical structures. Digital 3D models can become a platform for the application of various virtual realities (VR) and artificial intelligences in medical education.

Conservative Management of Symptomatic Sacral Tarlov Cyst - A Rare Case Report

Introduction

Tarlov cysts are rare perineural cysts noted as an incidental finding in approximately 1% of lumbar magnetic resonance imaging (MRI) arising from extradural components near the dorsal root ganglion. Due to its localization, it may cause sensory symptoms in some cases. However, most of these cysts are asymptomatic.

Case Report

We present the case of a 55-year-old woman with complaints of severe pain localized to the inner aspect of the thigh and gluteal region for the past 6 months, which has not been relieved by conservative management. On examination, there was a loss of sensation around the S2 and S3 dermatome with preserved motor functions. MRI showed a cystic lesion occupying the spinal canal with a size of about 1.3 × 0.7 cm with remodeling changes around the S2 vertebra. The cyst appears hypointense on T1 and hyperintense T2-weighted images. The diagnosis of the symptomatic Tarlov cyst was made and was managed with an epidural steroid injection. The patient was relieved of symptoms and remained asymptomatic till the latest follow-up at 1 year.

Conclusion

Symptomatic presentation of Tarlov cyst though rare should be considered and managed appropriately if identified as the source of symptoms. Conservative management with epidural steroids is a successful method in the management of smaller cysts without motor symptoms.

Multifocal hydatidosis with extensive involvement of the sacrum and the femoral head

Key Clinical Message

Hydatidosis is a parasitic infection caused by the larval form of "Echinococcus granulosis." Bone localization is rare even in endemic areas. We report an unusual case of an extensive hydatidosis of the right sacrum and femur with muscle involvement.

Abstract

We report the case of a man, with a history of visceral hydatidosis, who developed after 14 years an extensive hydatidosis of the sacrum and femur with muscle involvement. The treatment of visceral hydatidosis was chemotherapy with albendazole for a long term. Conservative surgical treatment is considered for bone locations.

Minimally invasive management of pathologic fractures of the pelvis and sacrum: Tumor ablation and fracture stabilization

BACKGROUND

Pathologic fractures of the pelvis/sacrum due to metastatic bone disease (MBD) cause pain and dysfunction due to mechanical instability of the pelvic ring. This study presents our multi-institutional experience with percutaneous stabilization of pathologic fractures and osteolytic lesions from MBD throughout the pelvic ring.

METHODS

The records of patients undergoing this procedure from 2018 to 2022 were reviewed retrospectively from two institutions. Surgical data and functional outcomes were recorded.

RESULTS

Fifty-six patients underwent percutaneous stabilization, with a median operative duration of 119 min (interquartile range [IQR]: 92.8, 167) and median estimated blood loss of 50 mL (IQR: 20, 100). The median length of stay was 3 days (IQR: 1, 6), and 69.6% (n = 39) of patients were discharged home. Early complications included one partial lumbosacral plexus injury, three acute kidney injuries, and one case of intra-articular cement extravasation. Late complications included two infections and one revision stabilization procedure for hardware failure. Mean Eastern Cooperative Oncology Group (ECOG) scores improved from 3.02 (SD 0.8) preoperatively to 1.86 (SD 1.1) postoperatively (p < 0.001). Ambulatory status also improved (p < 0.001).

CONCLUSIONS

Percutaneous stabilization of pathologic fractures and osteolytic defects of the pelvis and sacrum is a procedure that improves patient function, ambulatory status and is associated with a limited complication profile.

Auricular surface morphology and surface area does not influence subchondral bone density distribution in the dysfunctional sacroiliac joint

The subchondral lamella of the sacroiliac auricular surface is morphologically inconsistent. Its morpho-mechanical relationship with dysfunction (SIJD) remains unstudied. Here, the iliac and sacral subchondral bone mineralization is compared between morphological subtypes and in large and small surfaces, in SIJD joints and controls. CT datasets from 29 patients with bilateral or unilateral SIJD were subjected to CT-osteoabsorptiometry. Surface areas and posterior angles were calculated and surfaces were classified by size: small (<15 cm³ ) and large (≥15 cm³ ), and morphological types: 1 (>160°), 2 (130°-160°), and 3 (<130°). Mineralization patterns were identified: two marginal (M1 and M2) and two non-marginal (N1 and N2). Each sacral and iliac surface was subsequently classified. Dysfunctional cohort area averaged 15.0 ± 2.4 cm² (males 16.2 ± 2.5 cm² , females 13.7 ± 1.6 cm² ). No age correlations with surface area were found nor mean Hounsfield Unit differences when comparing sizes, sexes or morphology-type. Controls and dysfunctional cohort comparison revealed differences in female sacra (p = 0.02) and small sacra (p = 0.03). There was low-conformity in marginal and non-marginal patterns, 26% for contralateral non-dysfunctional joints, and 46% for dysfunctional joints. The majority of painful joints was of type 2 morphology (59%), equally distributed between small (49%) and large joints (51%). Larger joints had the highest frequency of dysfunctional joints (72%). Auricular surface morphology seems to have little impact on pain-related subchondral lamella adaptation in SIJD. Larger joints may be predisposed to the onset of pain due to the weakening of the extracapsular structures. Dysfunctional joints reflect common conformity patterns of sacral-apex mineralization with corresponding superior corner iliac mineralization.

Feasibility of intrathecal therapeutic injections in spinal muscular atrophy patients via a percutaneous transsacral hiatus route: An initial neuroimaging morphometric study

INTRODUCTION/AIMS

Standard fluoroscopic lumbar puncture (LP) can be impossible in patients with severe spinal deformities from spinal muscular atrophy (SMA) who require intrathecal nusinersen therapy. There usually exists a straight trajectory in the lower sacral canal (SC) that could allow image-guided percutaneous transsacral hiatus puncture of the lumbosacral dural sac. In this study we determine whether sacra are comparatively straighter in SMA patients (SMAps) vs healthy controls (HCs), which may facilitate unhindered transsacral hiatus spinal needle insertion for intrathecal nusinersen therapy.

METHODS

We retrospectively analyzed lumbosacral spine computed tomograms (CTs) or CT-myelogram images of 38 SMAps and age- and sex-matched HCs. We digitally measured ventrodorsal sacral curvatures, SC surface areas, dural sac termination levels, and distances from sacral hiatus to the most caudad aspects of dural sacs ("needle distance").

RESULTS

Mean ages of HCs and SMAps were 32.7 and 31.7 years, respectively, with dural sacs terminating at similar levels. Mean values for morphometrics were: (a) midsagittal SC surface area for HCs = 701.2 mm² , and for SMAps = 601.5 mm² (not statistically significant [ns]); (b) using a "line method," sacral curvature for HCs = 61.9°, and SMAp = 35.7° (P = .0009), and was similar when using an "angle summation method"; (c) width of sacral hiatus for HCs = 14.9 mm, and SMAps = 15.0 mm (ns); and (d) "needle distance" for HCs = 54.7 mm, and SMAps = 49.9 mm (ns).

DISCUSSION

SMAps have significantly straighter sacra compared with HCs, which theoretically renders them more amenable to percutaneous transsacral hiatus puncture of the dural sac.

RunScribe Sacral Gait Lab™ Validation for Measuring Pelvic Kinematics during Human Locomotion at Different Speeds

Optoelectronic motion capture systems are considered the gold standard for measuring walking and running kinematics parameters. However, these systems prerequisites are not feasible for practitioners as they entail a laboratory environment and time to process and calculate the data. Therefore, this study aims to evaluate the validity of the three-sensor RunScribe Sacral Gait Lab™ inertial measurement unit (IMU) in measuring pelvic kinematics in terms of vertical oscillation, tilt, obliquity, rotational range of motion, and the maximum angular rates during walking and running on a treadmill. Pelvic kinematic parameters were measured simultaneously using an eight-camera motion analysis system (Qualisys Medical AB, GÖTEBORG, Sweden) and the three-sensor RunScribe Sacral Gait Lab™ (Scribe Lab. Inc. San Francisco, CA, USA) in a sample of 16 healthy young adults. An acceptable level of agreement was considered if the following criteria were met: low bias and SEE (<0.2 times the between-subject differences SD), almost perfect (r > 0.90), and good reliability (ICC > 0.81). The results obtained reveal that the three-sensor RunScribe Sacral Gait Lab™ IMU did not reach the validity criteria established for any of the variables and velocities tested. The results obtained therefore show significant differences between the systems for the pelvic kinematic parameters measured during both walking and running.

Patterns of Failure After Stereotactic Body Radiotherapy to Sacral Metastases

AIMS

Stereotactic body radiotherapy (SBRT) is increasingly used to treat sacral metastases. We analysed our centre's local relapse rates and patterns of failure after sacral SBRT and assessed whether using the consensus contouring recommendation (CCR) may have prevented local relapse.

MATERIALS AND METHODS

We conducted a single-centre retrospective review of patients treated with sacral SBRT between February 2012 and December 2021. The cumulative incidence of local relapse, patterns of failure and overall survival were determined. Two investigators reviewed planning computed tomography scans and imaging at relapse to determine if local relapse was potentially preventable with a larger CCR-derived radiotherapy field.

RESULTS

In total, 34 patients received sacral SBRT, with doses ranging from 24 to 40 Gy over three to five fractions. The most frequently used schedule was 30 Gy in three fractions. Common primaries treated included prostate (n = 16), breast (n = 6), lung (n = 3) and renal (n = 3) cancers. The median follow-up was 20 months (interquartile range 13-55 months). The cumulative incidence of local relapse (4/34) was 2.9% (95% confidence interval 0.2-13.2), 6.3% (95% confidence interval 1.1-18.5) and 16.8% (95% confidence interval 4.7-35.4) at 6 months, 1 year and 2 years, respectively. The patterns of failure were local-only (1/34), local and distant (3/34) and distant relapse (10/34). The overall survival was 96.7% (95% confidence interval 90.5-100) and 90.6% (95% confidence interval 78.6-100) at 1 and 2 years, respectively. For prostate/breast primaries, the cumulative incidence of local relapse was 4.5% (95% confidence interval 0.3-19.4), 4.5% (95% confidence interval 0.3-19.4) and 12.5% (95% confidence interval 1.7-34.8) at 6 months, 1 and 2 years, respectively. Twenty-nine cases (85.3%) deviated from the CCR. Sacral relapse was potentially preventable if the CCR was used in one patient (2.9% of the whole cohort and 25% of the relapsed cohort).

DISCUSSION

We have shown excellent local control rates with sacral SBRT, which was largely planned with a margin expansion approach.

Living with a C2-Sacrum Spinal Fusion: Surgical Outcomes and Quality of Life in Patients Fused from C2 to the Sacrum

STUDY DESIGN

Single center, retrospective cohort study.

OBJECTIVES

Little is known about the surgical outcomes and quality of life in patients with C2-sacrum posterior spinal fusion (PSF). Though it is thought to be a "final" construct, it remains unknown how patients fare postoperatively. We sought to evaluate the surgical outcomes and quality of life of patients after C2-sacrum PSF.

METHODS

Consecutive patients undergoing C2-Sacrum PSF from 2015-2020 by 4 surgeons at a single institution were included. The study time period for each patient began after their index operation that led to the C2-sacrum fusion. Dates of surgery, complications, reoperations, patient reported outcomes (PROs) including EuroQol 5 Dimensions (EQ-5D), Oswestry Disability Index (ODI), Scoliosis Research Society (SRS) questionnaires, and activities of daily living (ADL) questions were collected and analyzed. Descriptive statistics, paired t-tests, student t-tests, and linear regression were used.

RESULTS

Of the 23 patients who underwent C2-sacrum PSF, 6 patients (26%) required a total of 10 reoperations after a mean of 1.5 years (range 0-4 years) after C2-sacrum PSF. Five reoperations were for mechanical failure; 3 for wound complications/infection; and 2 for instrumentation and spinous process prominence. PROs were collected on 18 patients with mean follow-up of 2.4 years (range .5-4.5) after their C2-sacrum PSF. At 6-months, both SRS-22 and ODI scores improved significantly after C2-sacrum PSF (SRS: 57.5 to 76.3, P = .0014; ODI: 47.0 to 31.7, P = .013). Similarly, at a mean 2.4 years postoperatively, mean ODI improved significantly (47.0 to 30.4, P = .0032). Six patients (33%) had minimal symptoms (ODI <20). The median postoperative EQ-5D score was .74 (range .19 to 1.0), which compares favorably to patients with hip/knee osteoarthritis (EQ-5D .63) and diabetes mellitus (DM) (EQ-5D .69) and hypertension (HTN). In terms of activities of daily living (ADL), 10 patients (56%) exercised regularly-a mean 4.5 days/week. 11 (61%) could do light aerobic activity (e.g. stationary bike). 10 (55%) were able to play with children/grandchildren as desired. Eight patients (44%) hiked, and 2 (11%) drove independently. 11 (61%) could tolerate short air-travel comfortably. Of the 17 patients who could toilet and perform basic hygiene preoperatively, 16 (94%) were able to do so postoperatively.

CONCLUSION

Though C2-sacrum PSF is thought to be a "final" construct, approximately 1 in 4 patients require subsequent operations. However, C2-sacrum PSF patients had a significant improvement in SRS and ODI scores by 6 months postop. Over 60% of patients were regularly performing light aerobic activity 2 years after their C2-sacrum PSF. EQ-5D suggests that this population fares better than those with degenerative hip/knee arthritis and similarly to those with common chronic conditions like DM and HTN.

Sacral Giant Cell Tumor Presenting as Low Back Pain in the Chiropractic Office: A Case Report

Sacral giant cell tumors are a rare cause of low back pain and may be challenging to identify via routine clinical examination and radiography. A 47-year-old woman presented to a chiropractor with a one-month history of worsening low back pain with radiation to the posterior thighs, worsened with ambulation, and used a cane to walk. She previously saw an orthopedic surgeon and was diagnosed with lumbar spondylosis, having tried anti-inflammatory medications, exercises, and acupuncture without success. The chiropractor ordered lumbar magnetic resonance imaging which revealed an aggressive sacral lesion and referred the patient to an oncologist. The oncologist performed positron emission tomography/computed tomography and biopsy, confirming a sacral giant cell tumor. A surgical team recommended tumor resection, lumbosacral fusion, radiotherapy, and zoledronic acid infusion. Sacral giant cell tumors are rare and may be challenging to identify via routine radiography. These tumors are an important differential to consider for patients with unexplained lumbosacral symptoms unresponsive to care.

Effect of IMU location on estimation of vertical ground reaction force during jumping

Introduction: Several investigations have examined utilizing inertial measurement units (IMU) to estimate ground reaction force (GRF) during exercise. The purpose of this investigation was to determine the effect of inertial measurement units location on the estimation of ground reaction force during vertical jumping. Methods: Eight male subjects completed a series of ten countermovement jumps on a force plate (FP). The subjects had an inertial measurement units attached to the sacrum, back and chest. Ground reaction force was estimated from data from the individual inertial measurement units and by using a two-segment model and combined sensor approach. Results: The peak ground reaction force values for the sacrum, back, chest and combined inertial measurement units were 1,792 ± 278 N, 1,850 ± 341 N, 2,054 ± 346 N and 1,812 ± 323 N, respectively. The sacral inertial measurement units achieved the smallest differences for ground reaction force estimates providing a root mean square error (RMSE) between 88 N and 360 N. The inertial measurement units on the sacrum also showed significant correlations in peak ground reaction force (p < 0.001) and average ground reaction force (p < 0.001) using the Bland-Altman 95% Limits of Agreement (LOA) when in comparison to the force plate. Discussion: Based on assessment of bias, Limits of Agreement, and RMSE, the inertial measurement units located on the sacrum appears to be the best placement to estimate both peak and average ground reaction force during jumping.

Assessment of regional sacral bone quality: A step towards patient-specific fracture fixation

Characterizing changes in sacral bone density could help us to inform instrumentation choices for procedures involving the sacrum. The aim of this study is to provide detailed maps of changes in sacral bone density across a series of patients using opportunistic quantitative computed tomography (QCT). We hypothesized that there would be significant differences in local cortical and trabecular bone density associated with age and sex. Fifty-four three-dimensional sacral models were segmented from routine clinical computed tomography scans, and detailed bone density estimates were derived for each bone using a calibrated opportunistic QCT approach. The effects of age and sex on cortical and trabecular bone density were determined across the sample. Overall cortical bone loss averaged 2.1 and 0.9 mg/cc per year, and trabecular bone loss was 1.6 and 0.7 mg/cc for female and males, respectively. Several regions had loss rates several times greater. Areas that were significantly affected by age included the vertebral bodies, bilateral ala, apex, and areas adjacent to both the anterior and posterior sacral foramina. Areas that were significantly affected by sex were the anterior sacral promontory, aspects of the ala. Bone density distribution across the sacrum changes nonuniformly due to factors including sex and age. Despite these overall trends, there remains significant variability between individuals. Clinical significance: This study provides detailed bone density information for both cortical and trabecular bone that could assist orthopaedic surgeons in planning surgical approaches to sacral fracture fixation.

Myxopapillary Ependymoma of the Sacrum

Teaching Point: Myxopapillary ependymoma presenting as a highly destructive lesion in the sacrum is rare but should be included in the differential diagnosis.

Morphometric Examination of the Sacroiliac Region and Variable Positions of the Sacral Auricular Surface: Anatomical Classification and Importance

OBJECTIVES

Anatomical variations of the sacrum involve alterations in the number of sacral segments, auricular surface area, and neural arch dimensions and are associated with biomechanical, surgical, and obstetric implications. Due to the complex functional structure of the sacroiliac (SI) joints, it was aimed to evaluate their morphometric structure, classify the sacrum, and group different locations of the auricular surface in the sacrums.

METHODS

Sex determination was made in 91 dry human sacra. Determination of the alpha angle on the sagittal axis of the auricular surface of the sacrum and classification of the auricular surface of the sacrum was performed. The sacra were studied to determine the position and extent of their auricular surfaces in relation to the sacral segments. Specimens were grouped as "normal," "high-up," and "low-down" auricular surface-bearing sacra. The sacral surface areas were measured, and SI joints were classified into three types morphologically (types I, II, and III). The depth and anterior-posterior length of the cranial, middle, and caudal impressions observed in the posterior sacrum and anterior-posterior lengths were measured.

RESULTS

The measurements made for sex determination showed that 46 of the sacra were from females and 45 were from males. The alpha angle on the sagittal axis of the sacral auricular surface was found to be greatest at the level of the first posterior sacral foramina. While the most common sacrum type was Type III, the least common type was Type I. The surface area of facies auricularis was found to be larger in males than in females. With regard to facies auricularis in all sacrum groups, although it covered approximately 2.5 sacral vertebrae, there was a difference in the location of facies auricularis in the sacral vertebrae. A statistically significant difference was found between right and left in the depth values of the impressions in the dorsal surface of the sacrum (p <0.05).

CONCLUSION

The position of the auricular surface in the sacrum differed among individuals. These differences are associated with variable load-bearing in the SI joints. The biomechanical classification of the sacrum and localization of the auricular surface can provide information about the anatomic source of low back pain or help predict the location of low back pain. Changes in the synovial surface morphology of the SI joints may elicit sacroiliac joint pain. This study was conducted because it is considered that the location of the auricular surface can significantly affect load-bearing patterns of the sacrum.

Alignment of the Sternum and Sacrum as a Marker of Sitting Body Posture in Children

An analysis of literature on the methods of assuming a sitting position and the results of our own research indicated the need to search for biomechanical parameters and existing relationships that would enable a description of sitting body posture. The purpose of this paper is to analyze the relationship between the alignment of the body of sternum and sacrum and the changes in the thoracic and lumbar spine curvatures in children. The study involved 113 subjects aged 9-13 years. A planned simultaneous measurement of the angle parameters of the alignment of the body of sternum and sacrum relative to the body's sagittal axis and the angle parameters of the thoracic and lumbar spine curvatures was performed during a single examination session. The proposed markers of alignment in the corrected sitting body posture are characterized by homogeneous results. A high measurement repeatability was observed when determining the corrected body posture in the study setting. It was noted that changes in the alignment of the body of sternum and sacrum resulted in changes in the thoracic kyphosis and lumbar lordosis angle values, which may be an important component of clinical observations of sitting body posture in children. Implementing the body of sternum alignment angle of about 64° relative to the body's sagittal axis in clinical practice as one of the objectives of postural education may be the target solution for sitting body posture correction in children.

Parasacral ischial plane block for lower limb wound debridement surgeries - A case series

Parasacral ischial plane block is a novel fascial plane approach to sacral plexus. Parasacral ischial plane block is technically less challenging and obviates the need for direct visualisation of sacral plexus. It can reliably be performed in limb-amputated patients where neuromuscular stimulation is less useful. Ten patients of the American Society of Anesthesiologists physical status II-IV, aged between 18 and 70 years, posted for elective lower limb debridement surgeries were enroled in this prospective case series. The time taken to perform the block was ≤4 minutes in all cases. Time taken for full sensory loss was 9 minutes to 15 minutes. None of the patients developed a complete motor blockade till 30 minutes after our observation. None of the patients required intraoperative supplemental analgesia. This block is technically easy, less time-consuming, and provided adequate sensory analgesia in below-knee surgeries.

Is "Trigonum sacrale" a real equilateral triangle? Anatomic consideration of sacral hiatus in adult: A three-dimensional CT study for reliable caudal access

This study is the first attempt to examine anatomical characteristics using three-dimensional computed tomography (3DCT) bone images with some parameters, in order to achieve correct and uncomplicated accesses. In addition, the study addresses a long-standing problem in the field and evaluates whether the trigonum sacrale forms an equilateral triangle or not. A detailed anatomic study of the sacral region was carried out on 91 patient 3DCT images. The CT data, in DICOM format, was read into VINCENT software from Fuji Film, with a slice thickness of 0.5 mm. The average length of sacral hiatus was 28.6 ± 8.4 (range 13.8-45.2 mm). The average width of sacral hiatus at the level of sacral cornua was 10.9 ± 2.7 (range 3.8-16.5 mm). The ratio between the length of the oblique and base line formed by the sacral triangle was 0.81 ± 0.12 (range 0.54-1.00). Using 3DCT images translated by the volume rendering technique, we can remove soft tissue from bones virtually. A slice thickness of 0.5 mm makes it a fine image, and permits meticulous measurement, which is different from previous cadaveric studies. Interestingly, our data showed that the ratio between oblique and base line on sacral triangle was <1.0, average 0.81. Findings demonstrated that the trigonum sacrale is not an equilateral triangle. This is useful information for the identification of the sacral hiatus when the landmark-based technique is employed.

What Radiographic and Clinical Factors Ultimately Necessitate a C2-Sacrum Instrumented Posterior Spinal Fusion?

OBJECTIVE

/Hypothesis: Patients undergoing C2-sacrum PSF have unique medical histories and multiple prior operations over an extended period.

DESIGN

Single center, retrospective cohort.

METHODS

Consecutive C2-sacrum PSF patients operated on by 4 surgeons at a single-center from 2015-2020 were reviewed. Demographics, comorbidities, indications, surgical history, and radiographic parameters were collected.

RESULTS

23 patients underwent C2-sacrum PSF. 13 (57%) were male, and 21 (91.3%) were adults. Mean age at time of first spine surgery was 44 years (range 5-71) and 53 years (range 14-72) at the time of C2-sacrum PSF. Six patients (26%) had osteoporosis, and 6 patients (26%) had neurologic comorbidities-including Parkinson's disease (4), cerebral palsy (1), and Brown Sequard syndrome (1). Four (17%) had connective tissue disease. Two patients underwent C2-sacrum PSF as an index procedure: (1) 67M with myelomatous fractures and 124° of cervicothoracic kyphosis; (2) 28F with severe Marfan syndrome with 140° thoracic scoliosis and 130° thoracic kyphosis. The remaining 21 (91%) underwent C2-sacrum PSF as a revision following prior spinal surgeries on average, 4 previous surgeries (range 1-13) over 10.5 years (range .3-37.4). Indications for the remaining 21 C2-sacrum PSF revision procedures included 17 (81%) for kyphosis (5 of whom also had significant coronal deformity), 1 (5%) for only coronal malalignment, 2 (10%) for instrumentation failure, and 1 (5%) for myelopathy.

CONCLUSIONS

91% (21/23) of patients requiring C2-sacrum PSF were treated as revisions of prior fusions, with a mean of 4 prior surgeries over 10 years. Over 80% of these patients underwent C2-sacrum PSF to address kyphosis. 26% had neurologic conditions, and 26% had osteoporosis.

Assessment of the acetabular version in relation to sagittal sacropelvic parameters

The relationship between acetabular orientation and the sacropelvic parameters is of interest to both hip and spine surgeons as it is increasingly clear disease in one area can affect the other, including the outcome of surgical procedures. The aim of this study was to further clarify the relationship between measures of acetabular orientation and sacropelvic parameters. This study utilized a trauma CT database. A total of 100 scans on adult patients without overt hip or spinal disease were included. Measures of acetabular orientation included the acetabular sagittal angle (ASA) which uses the anterior pelvic plane as a reference and sacroacetabular angle which uses the sacral endplate as a reference (SA); spinopelvic parameters include the pelvic incidence (PI), sacral anatomic orientation (SAO) and pelvic thickness (PTH). Mean age 48.2 years (SD 18.0), 62% male. Mean values were: PI 50.5, SAO 50.7, PTH 106.4 mm, ASA-right 62.1, ASA-left 64.0, SA-right 67.2, and SA-left 65.4. There was substantial correlation between PI and SA (r = 0.628-0.630) and also between SAO and SA (-0.657 to -0.692). Liner regression determined SA was best predicted by the model: SA = 81 × SAO + 0.36 × PI. When using the anterior pelvic plane as a reference to define acetabular orientation, there does not appear to be any significant relationship between the sagittal orientation of the acetabulum and sacropelvic parameters. Using the sacrum as a common point of reference allows some further understanding of the interplay between pelvic parameters and the orientation of the acetabulum.

A Case Report of a Vertical Zone III Sacral Fracture Due to Acute Lower Extremity Hyperabduction While Windsurfing

Typically associated with motor vehicle accidents and falls, sacral fractures result from sudden compression of the iliac wings, placing bidirectional traction forces on the anterior and/or posterior aspects of the sacrum. Here we describe a vertical Zone III sacral fracture caused by sudden, forceful hyperabduction of the lower extremities. To the authors' knowledge this is the first report of a Zone III sacral fracture caused by this mechanism which occurred when the patient encountered a large wave while windsurfing. Imaging revealed a longitudinal fracture to the anterior sacrum, with a concomitant Zone II fracture and pubic symphysis diastasis. The patient was treated using anterior fixation plating and posterior percutaneous pinning. The purpose of this study is to increase provider awareness of an often underdiagnosed fracture, alert water sports enthusiasts of the risks associated with windsurfing, describe signs and symptoms of this often overlooked fracture, and discuss treatment modalities based on radiographic and clinical assessments of fracture stability.

A Rare Case of Epithelioid Hemangioma Presenting as an Isolated Sacral Mass

Epithelioid hemangioma (EH) is an uncommon benign vascular tumor of mesenchymal origin. It mainly presents as expanding nodules around the ear, the forehead, and long bones. Only a handful of cases have been found in cervical, thoracic, lumbar, and sacral vertebrae as lytic lesions with pain and neurological impairment. We present the case of a 36-year-old female with an incidental finding of a sacral mass along with inguinal lymphadenopathy on imaging. Initially, there were no symptoms. The mass gradually progressed and later showed an extraosseous extension with involvement of sacral neural foramina and nerve roots causing severe low back pain and weakness of the left lower extremity. Differential diagnoses initially included secondary metastases and chordoma. However, the biopsy of the mass revealed findings consistent with an EH. To our knowledge, this is the first case of EH presenting as an isolated mass in the sacrum and the third case of EH involving the sacrum in continuation with other vertebrae. EH should be in our differential diagnoses when there is a sacral mass.

Morphological and morphometric features of sacral hiatus and its clinical significance in caudal epidural anaesthesia

BACKGROUND

Caudal epidural block (CEB) failure or complications are not unheard even among experienced anaesthesiologists and are usually due to sacral hiatus (SH) anatomy variations. The aim of the present study is to observe, record and analyse important anatomical features of SH and correlate them with potential CEB limitations.

MATERIALS AND METHODS

The SH of 155 complete and undamaged Greek adult dry sacra of known sex were included in the study. Three non-metric (shape of SH and location of hiatal apex and base in relation to level of sacral/coccygeal vertebra) and five metric parameters (height of the SH, transverse width of the SH at the base, anteroposterior diameter of the SH at the level of its apex and the distance from the sacral apex and base to the upper border of S2 foramina) were evaluated.

RESULTS

Inverted U (34.83%) and inverted V (26.45%) were the commonest shapes. Hiatal apex and base were most commonly related to the level of S4 (78.70%) and S5 vertebra (89.03%), respectively. Mean height, depth and intercornual distance were 19.05 ± 8.65 mm, 5.39 ± 1.84 mm and 12.41 ± 3.16 mm, respectively, whereas mean distance between the upper border of S2 foramen and the apex and base of the SH were 46.34 mm and 63.48 mm, respectively. Anatomical variations of SH that might be responsible for CEB failure, such as elongated SH, absence of SH, complete dorsal wall agenesis of sacral canal and narrowing (< 3 mm) at the apex of SH were found in 17.43% of sacra (male 10.94% and female 25.22%).

CONCLUSIONS

This study suggests a potential risk of failure of CEB in Greek patients, especially in females, which should be kept in mind while giving caudal epidural anaesthesia.

Comprehensive treatment outcomes of giant cell tumor of the spine: A retrospective study

There is no consensus on a treatment strategy for spinal giant cell tumor of bone (GCTB) because of the difficulty in their treatment. Treatment options often include the use of the controversial denosumab, an antibody therapy aimed at tumor shrinkage, different curettage techniques, resection, or a combination of these therapies. The current study aimed to identify treatment methods associated with favorable outcomes in patients with spinal GCTB. We retrospectively reviewed 5 patients with spinal GCTB, including patients with tumors of the sacrum, treated at our hospital between September 2011 and November 2020. Two men and 3 women were included in the study. The median follow-up period was 74 months (range: 14-108 months). We surveyed the tumor site, treatment method, denosumab use, and outcomes. The median age was 17 years (range: 17-42 years). There were 2 cases of sacral GCTB and 1 case each of lumbar, cervical, and thoracic vertebral GCTB. The comorbidities observed included hepatitis, malignant lymphoma, atopic dermatitis, and asthma. The treatment method included zoledronic acid after embolization and denosumab, denosumab only, curettage and posterior fusion, and curettage resection after embolization and anterior and posterior fusion. Denosumab was used in all cases. Three patients were continuously disease-free, 1 patient with no evidence of disease, and 1 patient alive with disease. Aggressive treatment, especially surgical treatment, may lead to good results in spinal GCTB.

Iatrogenic L5 Nerve Injury Following Decortication of the Sacral Ala in Posterolateral Lumbosacral Fusion Surgery

STUDY DESIGN

Cadaver study.

OBJECTIVES

To investigate the risk of the L5 nerve injury following sacral ala decortication performed during lumbosacral posterolateral fusion surgery.

METHODS

Fourteen fresh cadaver pelvises were dissected through an anterior approach and the L5 nerves on both sides were explored and macroscopically examined by direct observation. Then, the corticotomy of the sacral ala was performed at 0°, 20°, and 30° angles to the sagittal plane through the posterior approach. The site of sacral ala decortication was checked on each side and its distance to the L5 nerve root was measured.

RESULTS

The tip of the osteotome was in the danger zone (5 mm medial to 5 mm lateral to the L5 nerve) in all cases (100%) where the osteotome had 0° angle to the sagittal plane. For those with a 20° angle, the osteotome tip laid in the danger zone in 83% and intermediate zone (between 6 to 15 mm lateral to the nerve) in 17% of cases. For those with a 30° angle, the tip was in the safe zone (>15 mm lateral to the nerve) in all cases (100%).

CONCLUSION

Osteotomy of the sacral ala with <30° angle to the sagittal plane risks injury to the L5 nerve; whereas osteotomy angle >30° would not cause any injury to the nerve. It should be considered as a possible cause of iatrogenic L5 nerve injury in patients undergoing posterolateral lumbosacral fusion.

Impact of local treatment modality on overall- and disease-specific survival for nonmetastatic pelvic and sacral Ewing sarcoma

PURPOSE

The ideal local treatment modality for pelvic and sacral Ewing sarcoma (EWS) is controversial.

METHODS

We present the data from the American College of Surgeon's National Cancer Database (NCDB) and the National Cancer Institute's Surveillance, Epidemiology and End Result (SEER) database to investigate the impact of local treatment modalities on survival for nonmetastatic pelvic and sacral Ewing sarcoma. Local treatment includes "surgery," "radiation," and a combination of "surgery and radiation."

RESULTS

A total of 235 cases from SEER and 285 cases from NCDB were analyzed. Patients with "localized" stage (intraosseous) in the SEER database did not show any statistically significant difference in the disease-specific survival (DSS) for any of the local treatment modalities. Similar findings were observed for overall survival among patients with American Joint Committee on Cancer (AJCC) stage II and III in the NCDB database. However, patients with nonmetastatic disease, particularly regional disease (extraosseous), showed improved DSS with surgery only, in the SEER.

CONCLUSION

We found similar levels of efficacy for different treatment modalities for patients with intraosseous and AJCC II and III pelvic and sacral EWS. "Radiotherapy" is the most common local treatment modality employed in the United States. A prospective, randomized controlled trial with a direct head-to-head comparison is needed for a definitive conclusion.

Sacro-pelvic Anthropometry in the Portuguese Population and Its Implication for Screw Placement in Spinal Surgery: A Single Centre Retrospective Analysis

Objective  The aim of this study was to assess the sacropelvic anthropometry in the Portuguese population, through the study of pelvic computed tomography (CT) scans. Methods  Pelvic CT scans of 40 individuals were analyzed, and the length and angle measurements were performed according to predefined screw trajectories of S1 anterior (S1A), anterolateral (S1AL) and anteromedial (S1AM), S2 anterolateral (S2AL) and anteromedial (S2AM), S2 alar iliac (S2AI), iliac, and sacroiliac (SI) screws. Comparisons between genders were also performed. Results  The S1A screw trajectory mean length was 30.80 mm. The S1AL mean length and lateral angle were 36.48 mm and 33.13°, respectively, and the S1AM's were 46.23 mm and 33.21°. The S2AL mean length was 28.66 mm and lateral angle was 26.52°, and the S2AM length and angle were 29.99 mm and 33.61°, respectively. The S2 alar-iliac screw trajectory mean length, lateral, and caudal angles were 125.84 mm, 36.78°, and 28.66°, respectively. The iliac screw trajectory mean length, lateral, and caudal angles were 136.73 mm, 23,86° and 24.01°, respectively. The sacroiliac screw trajectory length was 75.50 mm. The length of the screws was longer in men than in women, except for the S1A and SI screws, for which no difference was found between genders. Conclusion  This study describes sacropelvic anatomical specifications. These defined morphometric details should be taken into consideration during surgical procedures.

Challenges and Complications in Freehand S2-Alar-Iliac Spinopelvic Fixation and the Potential for Robotics to Enhance Patient Safety

STUDY DESIGN

Narrative Summary Review for Navigation & Robotics Focus Issue.

OBJECTIVE

To discuss the challenges and complications of S2-Alar-Iliac (S2AI) spinopelvic fixation using freehand techniques, and to introduce the utility of navigation & robotics to enhance patient safety.

METHODS

This study involved search of literature using the PubMed database, including retrospective clinical studies, anatomic reports, and surgical reports. The intention was to find literature that discussed complications regarding screw malfunction from manual S2AI placement, anatomical complexity of the sacroiliac joint, and outcomes of S2AI procedures conducted with robotic guidance systems.

RESULTS

The sacroiliac joint presents numerous complexities that can lead to challenges in free-hand placement of the S2-alar-iliac screw. Anatomic considerations of the S2AI screw involve close proximity to vital neurovascular structures, including: superior gluteal vessels, external iliac vessels, pudendal vessels, superior gluteal nerves, sciatic nerve, sympathetic chain ganglia, and pudendal nerves. The complications associated with manual S2AI screw installation include screw misplacement, breach of cortical bone, and injury to neurovascular structures. Robotic techniques for establishing S2AI screws involve greater accuracy of screw placement and reduced complications.

CONCLUSIONS

Accurate placement of S2AI screws is compromised by variation in pelvic anatomy and by a pathway that traverses dense cortical bone of the sacroiliac joint. Accurate placement of S2AI screws is important for patient safety regarding neurovascular structures, and for effective, stable fixation across the SI joint. Robotic navigation of S2AI fixation offers significant utility in improving the accuracy of screw placement and patient safety.

Observations of different types of sacra in Greyhounds based on the occurrence of sacrocaudal fusion

Little attention has been paid to the normal fusion of the vertebrae of greyhounds despite the common occurrence of sacrocaudal fusion. The current study aimed to investigate and provide data on the morphology of different types of fused sacra (B, C and D) in greyhounds and also to determine the potential association between the sex, body mass and morphology of fused sacra (S. Weight, S. Length and S. Width) in greyhounds. The sacra were collected from 171 greyhounds from Melbourne, Australia. After classifying the sacra based on the occurrence and types of the sacrocaudal fusion, they were measured for weight of the sacrum, length of sacrum and the width of sacrum. Multiple linear regression analyses were used to quantify the association between weight of the sacrum (as the outcome variable) type of sacrum (A, B, C and D), body mass and sex (as explanatory variables). The results proved that there are measurable differences between each type of fused sacra (B, C and D) and the standard sacra (A). In addition, this study showed that sex or body mass do not influence the occurrence of different types of fusion. The results of this study showed that the occurrence of sacrocaudal fusions was independent of body size in this population of greyhounds. Sacrocaudal fusion might affect the biomechanics in greyhounds independently of effects of body size.

Frequency of and risk factors for intensive care unit-acquired sacrum pressure injuries in critically ill patients: A multicenter cross-sectional study in China

RATIONALE AIMS AND OBJECTIVES

Hospital-acquired pressure injuries (HAPI) prolong hospital stays and are an important health problem worldwide. The aim of this study was to assess the frequency of and risk factors for intensive care unit (ICU)-acquired pressure injuries (IAPI) on the sacrum in critically ill patients in China.

METHODS

We performed a multicenter, cross-sectional survey of IAPI on the sacrum in 23 adult ICUs in 19 hospitals in China. Data for 421 critically ill patients were collected on December 13, 2019, and January 13, 2020, including patient characteristics, physiological, and clinical information. Logistic regression was used to analyze the risk factors for IAPI on the sacrum in the ICU.

RESULTS

Forty-one patients presented sacrum pressure injuries in the ICU, with a frequency of 9.74%. Risk factors that significantly increased the risk of IAPI on the sacrum were lower body mass index (BMI, odds ratio [OR] = 1.115, confidence interval [CI]: 1.011-1.229, P = .029), chronic obstructive pulmonary disease (COPD, OR = 3.183, CI: 1.261-8.037, P = .014), multiple organ dysfunction syndrome (MODS, OR = 2.670, CI: 1.031-6.903, P = .043), and a lower Braden risk score (OR = 1.409, CI: 1.197-1.659, P < .001).

CONCLUSION

Lower BMI, COPD, MODS, and lower Braden risk score are independent risk factors for sacrum IAPI in China.

Novel Multimodal Treatment Regimen for the Management of Primary Sacrococcygeal Cystic Echinococcosis

INTRODUCTION

Osseous hydatidosis is a rare condition most commonly involving the spine. Among spinal segments, sacrococcygeal involvement is even rarer. Moreover, the lesion is more prone to recurrence owing to the infiltrative nature of microvesicular lesions involving the spine. In this case report, we describe an effective multimodal management approach toward the management of primary sacrococcygeal cystic echinococcosis.

CASE REPORT

A 56-year-old female presented with complaints of severe back pain and urinary incontinence for 3 months. She presented with a slow-onset cauda equina syndrome with radiating pain to both lower limbs. Radiographic evaluation showed an expansile lytic lesion affecting the right iliac wing with near-complete cortical bone destruction of the sacrum. Magnetic resonance imaging revealed neural involvement with sacral destruction by a multiloculated cystic mass, extending to the spinal canal. No coexisting lesions were noted anywhere. Echinococcosis was diagnosed with serum enzyme-linked immunosorbent assay. She underwent neoadjuvant therapy with albendazole and praziquantel, followed by ultrasound-guided percutaneous aspiration injection and reaspiration (PAIR) with hypertonic saline followed by sclerosant (95% ethyl alcohol) into the residual cyst cavity. Later, she open excision of the residual multiloculated cystic mass was performed. Adjuvant medical therapy was continued for 3 months post-surgery. The patient regained her neurological functions by 6 months without any residual sequelae or symptomatic recurrence until 4 years of follow-up.

CONCLUSION

Multimodal treatment regimen comprising of oral medical therapy by albendazole and praziquantel along with PAIR and surgical in toto excision of the cyst followed by post-operative oral medical therapy for 3 months has given excellent results in sacrococcygeal cystic echinococcosis.

Minimally Invasive Resection of an S3 Osteoid Osteoma Using an Intraoperative O-Arm: A Technical Note

Osteoid osteomas are benign primary bone tumors that typically arise in posterior vertebrae of the spine. For patients with severe pain or those poorly controlled with non-steroidal anti-inflammatory drugs, surgical management is the mainstay of treatment. The recommended surgical treatment option is complete open excision, although minimally invasive CT-guided percutaneous excision and CT-guided radiofrequency ablation have been reported. Open resection can result in prolonged hospital stays, activity restrictions, and possible spinal destabilization. We sought to utilize a lateral minimally invasive approach. We highlight the importance of aggressive surgical resection and the utility of using fluoroscopy and O-arm guidance to optimize the extent of resection. We report a pediatric case of a 12-year-old male who presented with an S3 osteoid osteoma. The patient underwent a minimally invasive resection with complete resection and confirmation of the histopathologic diagnosis. Postoperative imaging showed complete resection of the tumor. The patient went home five hours after surgery with return to daily activities; his symptoms resolved completely. However, the patient had symptomatic recurrence and underwent a second more aggressive minimally invasive resection using O-arm guidance. At the current three-month follow-up, the patient is symptom- and tumor-free. The minimally invasive resection of a pediatric sacral osteoid osteoma is a valid alternative to standard open resection and is associated with a decreased blood loss, decreased length of stay in the hospital, and decreased time to full functional recovery. The pitfalls are learning curve and risk of incomplete resection that can be counterbalanced with an intraoperative O-arm to guide resection and confirm complete excision.

Novel wrapping surgery for symptomatic sacral perineural cysts

OBJECTIVE

Perineural cysts, also called Tarlov cysts, are dilatations of the nerve root sleeves commonly found in the sacrum. The majority of the cysts are asymptomatic and found incidentally on routine spine imaging. Symptomatic sacral perineural cysts (SPCs) that induce intractable low-back pain, radicular symptoms, and bladder/bowel dysfunction require surgery. However, the surgical strategy for symptomatic SPCs remains controversial. The authors hypothesized that the symptoms were caused by an irritation of the adjacent nerve roots caused by SPCs, and developed a wrapping surgery to treat these cysts.

METHODS

Seven patients with severe unilateral medial thigh pain and ipsilateral SPCs were included. Preoperative MRI showed that the cysts were severely compressing the adjacent nerve roots in all patients. After a partial laminectomy of the sacrum, the SPCs were punctured and CSF was aspirated to reduce their size, followed by dissection of the adjacent nerve roots from the SPCs. The SPCs were then wrapped with a Gore-Tex membrane to avoid reexpansion.

RESULTS

All 7 patients experienced substantial relief of their symptoms. The average numeric rating scale pain score was reduced from an average preoperative value of 7.9 to 0.6 postoperatively. Postoperative MRI showed that all cysts were reduced in size and the adjacent nerve roots were decompressed. Regrowth of the treated cysts or recurrence of the symptoms did not occur during the entire follow-up period, which ranged from 39 to 90 months. No complications were noted.

CONCLUSIONS

The authors' new wrapping technique was effective in relieving radicular symptoms for patients with symptomatic SPCs. The results suggested that the symptoms stemmed from compression of the adjacent nerve roots caused by the SPCs, and not from the nerve roots in the cysts.

Significance of Lumbar MRI in Diagnosis of Sacral Insufficiency Fracture

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

The aim of the present study was to evaluate the role of lumbar magnetic resonance imaging (MRI) in the diagnostic algorithm of sacral insufficiency fractures (SIF). The primary objective was to compare the sensitivity in fracture detection and correct fracture classification according to MRI and computed tomography (CT). The secondary objective was to identify differences of additional pathologies found in MRI of the lumbar spine and the pelvis and their rates.

METHODS

A total of 943 patients (from 2010 to 2017) with fracture of the pelvic ring were screened. All patients without high-energy trauma and radiologic diagnostics consisting of X-ray, CT, and MRI of the pelvis or the lumbar spine including the sacrum were included. Differences in fracture detection and description in the various radiologic procedures were evaluated. Detection rates of additional pathologies in MRI of the pelvis and lumbar spine were recorded.

RESULTS

A total of 77 subjects were included. The sensitivities for SIF were 14% in X-ray and 88% in CT, and all fractures were detected in MRI. MRI showed a more complex fracture pattern compared with CT in 65% of the cases. Additional pathologies were seen in MRI of the lumbar spine (51%) and that of the pelvis (18%).

CONCLUSIONS

We suggest performing MRI of the lumbar spine including the sacrum with coronal STIR (short tau inversion recovery) sequence for elderly patients with suddenly increasing low back pain at an early stage. This procedure might improve fracture detection, classification, and recognition of concomitant pathologies.

Cytological detection of metastatic chordoma cells in pleural effusions: A case report

Cytological detection of chordoma cells in the serosal cavity is challenging because of its rare presentation. Herein, we report a case of chordoma showing malignant pleural effusion accompanied by pleuropulmonary metastases in a 68-year-old woman. Cytological analysis was performed using pleural fluid obtained following thoracentesis. Conventional cytological staining demonstrated few clusters of large, atypical cells characterized by epithelial cell-like connectivity and rich cytoplasm with foamy and/or multivacuolar changes. The nuclei of these atypical cells were large and either round or oval with no conspicuous irregularities in the nuclear membrane. Periodic acid-Schiff staining of these atypical cells revealed fine granules in the cytoplasm. Giemsa staining showed foamy and/or multivacuolar cytoplasm in these cells, with metachromatic mucoid stroma in the surroundings. Immunocytochemistry analysis using cellblock showed these cells to be positive for broad cytokeratins, epithelial membrane antigen, S100 protein, vimentin, and Brachyury. To the best of our knowledge, this is the first case report in which chordoma cells were cytologically detected in pleural effusions. Our findings also suggest that conventional cytology combined with cellblock immunocytochemistry can increase the accuracy of chordoma cell detection in the serosal cavity.

Preliminary experience using S1-alar iliac fixation with navigation: technical note

Traditional iliac screws and S2-alar iliac (S2-AI) screws are common methods used for pelvic fixation, and many surgeons advocate pelvic fixation for long-segment fixation to the sacrum. However, in patients without severe deformities and only degenerative conditions, many surgeons may choose S1 screws only. Moreover, even with S2-AI screws, there is more muscular dissection than with using S1 screws, and the rod connection can be cumbersome in both S2-AI fixation and placing iliac screws. Using a surgical video, artist's illustration, and intraoperative photographs, the authors describe the S1-AI screw fixation technique that allows for single-screw sacral and iliac fixation, requires less distal dissection of the sacrum, allows for easier rod connection, and may be an option in degenerative conditions needing pelvic fixation. However, this is a preliminary feasibility study, and in long fusion constructs, this type of fixation has only been used in conjunction with L5-S1 anterior lumbar interbody fusion (ALIF), and there are no long-term data on the use of this screw fixation technique without ALIF. In short-segment revision fusions, this technique may be considered for salvage in cases of large halos in the sacrum from loosened S1 screw fixation.

Retrospective lumbosacral CT analysis and prospective observational study of the ipsilateral tunnel view technique for fluoroscopy-guided selective S1 transforaminal epidural injection

BACKGROUND

The purpose of this study was to retrospectively observe the anatomic relationship between dorsal S1 foramen (DS1F) and ventral S1 foramen (VS1F) through computed tomography (CT) analysis and to prospectively determine the optimal angle of ipsilateral tunnel view technique for performing S1 transforaminal epidural steroid injection (S1-TFESI).

METHODS

The axial lumbosacral CTs taken between in 208 consecutive patients and the following measurements were obtained on both sides: (1) the α-angle was defined as an angle between a sagittal line passing through the center of the sacrum and an imaginary line passing through the center of DS1F, (2) the largest diameter of DS1F and VS1F. The fluoroscopy was adjusted to show the largest L5/S1 intervertebral disc space, which was defined as the cephalad angle, and tilted to the ipsilateral oblique side until the entrance of DS1F had a well-defined, round shape, which defined as the β-angle in 40 humans.

RESULTS

CT measurements showed that the α-angle was 26.3 ± 3.3 degrees (15-38 degrees) and the diameter of DS1F was 7.1 ± 0.7 mm (4-10.9 mm), which was significantly smaller than the diameter of VS1F, 10.1 ± 1.0 mm (7.2-13.8 mm). The β-angle was 24 ± 4.6 degrees, which was not much different from the α-angle and the cephalad angle was 23 ± 4.6 degrees. The success rate of S1-TFESI was 100% and there were no procedure-related complications.

CONCLUSIONS

The entrance of DS1F is easily identified with an ipsilateral 25 degrees-tunnel view technique while performing S1-TFESI, and it is a clinically applicable approach.