Lumbosacral Junction Research Articles

Biomechanics of a laterally placed sacroiliac joint fusion device supplemental to S2 alar-iliac fixation in a long-segment adult spinal deformity construct: a cadaveric study of stability and strain distribution.

S2 alar-iliac (S2AI) screw fixation effectively enhances stability in long-segment constructs. Although S2AI fixation provides a single transarticular sacroiliac joint fixation (SIJF) point, additional fixation points may provide greater stability and attenuate screw and rod strain. The objectives of this study were to evaluate changes in stability and pedicle screw and rod strain with extended distal S2AI fixation and with supplemental bilateral integration of two sacroiliac joint fusion devices implanted using a traditional minimally invasive surgical approach. Eight L1-pelvis human cadaveric specimens underwent pure moment (7.5 Nm) and compression (400 N) tests under 4 conditions: 1) intact (pure moment loading only); 2) L2-S1 pedicle screw and rod with L5-S1 interbody fusion; 3) added S2AI screws; and 4) added bilateral laterally placed SIJF. Range of motion (ROM), rod strain, and screw-bending moment (S1 and S2AI) were analyzed. Compared with S1 fixation, S2AI fixation significantly reduced L5-S1 ROM in right lateral bending by 50% (0.11°, p = 0.049) and in compression by 39% (0.22°, p = 0.003). Compared with fixation ending at S1, extending fixation with S2AI significantly decreased sacroiliac joint ROM by 52% (0.28°, p = 0.02) in flexion, by 65% (0.48°, p = 0.04) in extension, by 59% (0.76°, p = 0.02) in combined flexion-extension, and by 36% (0.09°, p = 0.02) in left axial rotation. The addition of S2AI screws reduced S1 screw-bending moment during flexion (0.106 Nm [43%], p = 0.046). With S2AI fixation, posterior L5-S1 primary rod strain increased by 124% (159 μE, p = 0.002) in flexion, by 149% (285 μE, p = 0.02) in left axial rotation, and by 99% (254 μE, p = 0.04) in right axial rotation. Compared with S2AI fixation, the addition of SIJF reduced L5-S1 strain during right axial rotation by 6% (28 μE, p = 0.04) and increased L5-S1 strain in extension by 6% (28 μE, p = 0.02). Long-segment constructs ending with S2AI screws created a more stable construct than those ending with S1 screws, reducing lumbosacral and sacroiliac joint motion and S1 screw-bending moment in flexion. These benefits, however, were paired with increased rod strain at the lumbosacral junction. The addition of SIJF to constructs ending at S2AI did not significantly change SI joint ROM or S1 screw bending and reduced S2AI screw bending in compression. SIJF further decreased L5-S1 rod strain in axial rotation and increased it in extension.

Safety and efficacy of stand-alone anterior lumbar interbody fusion in low-grade L5-S1 isthmic spondylolisthesis

IntroductionSurgical management of isthmic spondylolisthesis is controversial and reports on anterior approaches in the literature are scarce. Research questionTo evaluate the safety and efficacy of stand-alone anterior lumbar interbody fusion (ALIF) in patients with symptomatic low-grade L5-S1 isthmic spondylolisthesis. Material and methodsAll adult patients with isthmic spondylolisthesis of the lumbosacral junction treated in a single institution between 2008 and 2019 with stand-alone ALIF were screened. A titan cage was inserted at L5-S1 with vertebral anchoring screws. Prospectively collected surgical, clinical and radiographic data were analyzed retrospectively. Results34 patients (19 men, 15 women, mean age 52.5 ​± ​11.5 years) with a mean follow-up of 3.2 (±2.5) years were analyzed. 91.2% (n ​= ​31) of patients had a low-grade spondylolisthesis and 8.8% (n ​= ​3) grade III according to Meyerding classification. Mean COMI and ODI scores improved significantly from 6.9 (±1.5) and 35.5 (±13.0) to 2.0 (±2.5) and 10.2 (±13.0), respectively after one year, and to 1.7 (±2.5) and 8.2 (±9.6), respectively, after two years. The COMI and ODI scores improved in 86.4% and 80%, respectively, after one year and 92.9% of patients after two years by at least the minimal clinically important difference. No intraoperative complications were recorded. 8.8% (n ​= ​3) of patients needed a reoperation. Discussion and conclusionAfter stand-alone ALIF for symptomatic isthmic spondylolisthesis, the patients improved clinically important after one and two years. Stand-alone ALIF is a safe and effective surgical treatment option for low-grade isthmic spondylolisthesis.

Analysis of unfavorable postoperative outcomes in patients with lumbosacral junction anomalies

The absence of a unified diagnostic approach and heterogeneous treatment strategies in patients with lumbosacral transitional vertebra contribute to registration of contradictory data on postoperative outcomes in these patients. A retrospective analysis of postoperative outcomes in patients with degenerative lumbar spine diseases associated with lumbosacral junction anomalies and causes of unfavorable results. Lumbosacral transitional vertebra was preoperatively verified and classified according to Castellvi A.E. in 352 cases between 2007 and 2017. Full-time examination, phone and e-mail survey covered 314 (89.2%) patients throughout 5.2-year follow-up period. There were unfavorable clinical outcomes in 42 cases. We analyzed the causes of these results and relationship of surgical strategy with the type of lumbosacral junction anomaly. Lumbosacral transitional vertebra Castellvi type IIA (30.9%) and IIIA (34.9%) prevailed. Unfavorable outcomes occurred in 7 cases after percutaneous interventions, in 12 patients after decompression surgery and in 23 patients after decompression and stabilization procedures. In all cases (n=42), redo surgery was performed: rigid fixation or extension of stabilization system in 16 cases, additional intracanal decompression in 10 patients, foraminal/extraforaminal decompression in 8 patients. Seven patients underwent repeated laser denervation. Of these, 5 patients underwent dorsal decompression without discectomy due to ineffective denervation. Correlation analysis showed the relationship between unfavorable outcomes after percutaneous procedures with LV transverse process dysplasia and sacralization, decompressive interventions with additional articular joints and lumbarization, decompression/stabilization procedures with LV transverse process dysplasia and sacralization. Unfavorable outcomes occurred after percutaneous interventions for anomaly type IB and IIIB, decompressive procedures for anomaly type IIA, IIB and IV, decompression/ stabilization procedures for types IA and IIIA. It is the first report devoted to analysis of relationships between unsatisfactory postoperative outcomes, surgical technique and type of lumbosacral dysgenesis.

Unilateral Biportal Endoscopy for Decompression of Extraforaminal Stenosis at the Lumbosacral Junction: Surgical Techniques and Clinical Outcomes.

ObjectiveThe aims of this study were to describe the unilateral biportal endoscopic (UBE) technique for decompression of extraforaminal stenosis at L5–S1 and evaluate 1-year clinical outcomes. Especially, we evaluated compression factors of extraforaminal stenosis at L5–S1 and described the surgical technique for decompression in detail. MethodsThirty-five patients who underwent UBE decompression for extraforaminal stenosis at L5–S1 between March 2018 and February 2019 were enrolled. Clinical results were analyzed using the MacNab criteria, the visual analogue scale (VAS) for back and leg pain, and the Oswestry Disability Index (ODI). Compression factors evaluated pseudoarthrosis within the transverse process of L5 and ala of sacrum, disc bulging with or without osteophytes, and the thickened lumbosacral and extraforaminal ligament. ResultsThe mean back VAS was 3.7±1.8 before surgery, which dropped to 2.3±0.8 at 1-year postoperative follow-up (p<0.001). There was a significant drop in postoperative mean VAS for leg pain from 7.2±1.1 to 2.3±1.2 at 1 year (p<0.001). The ODI was 61.5 before surgery and 28.6 (p<0.001). Pseudoarthrosis between the transverse process and the ala was noted in all cases (35 of 35, 100%). Pure disc bulging was seen in 12 patients (34.3%), and disc bulging with osteophytes was demonstrated in 23 patients. The thickened lumbosacral and extraforaminal ligament were identified in 19 cases (51.4%). No complications occurred in any of the patients. ConclusionIn the current study, good surgical outcomes without complications were achieved after UBE decompression for extraforaminal stenosis at L5–S1.

A novel anatomo-physiologic high-grade spondylolisthesis model to evaluate L5 nerve stretch injury after spondylolisthesis reduction

L5 nerve palsy is a well-known complication following reduction of high-grade spondylolisthesis. While several mechanisms for its occurrence have been proposed, the hypothesis of L5 nerve root strain or displacement secondary to mechanical reduction remains poorly studied. The aim of this cadaveric study is to determine changes in morphologic parameters of the L5 nerve root during simulated intraoperative reduction of high-grade spondylolisthesis. A standard posterior approach to the lumbosacral junction was performed in eight fresh-frozen cadavers with lumbosacral or lumbopelvic screw fixation. Wide decompressions of the spinal canal and L5 nerve roots with complete facetectomies were accomplished with full exposure of the L5 nerve roots. A 100% translational slip was provoked by release of the iliolumbar ligaments and cutting the disc with the attached anterior longitudinal ligament. To evaluate the path of the L5 nerves during reduction maneuvers, metal bars were inserted bilaterally at the inferomedial aspects of the L5 pedicle at a distance of 10 mm from the midpoint of the L5 pedicle screws. There was no measurable change in length of the L5 nerve roots after 50% and 100% reduction of spondylolisthesis. Mechanical strain or displacement during reduction is an unlikely cause of L5 nerve root injury. Further anatomical or physiological studies are necessary to explore alternative mechanisms of L5 nerve palsy in the setting of high-grade spondylolisthesis correction, and surgeons should favor extensive surgical decompression of the L5 nerve roots when feasible.

The Contralateral Approach to intra- and Extraforaminal Lumbar Disk Herniations: Surgical Technique and Review of Surgical Procedures.

Surgery for intra-/extraforaminal disk herniations (IEDH) is technically demanding due to the hidden location of the compressed nerve root section. Ipsilateral approaches (medial and lateral) are accompanied by extended resection of the facet joint and inadequate visualization of the pathology, especially at the L5-S1 level. We describe a microsurgical interlaminar contralateral approach (MICA) suitable for IEDH at the lumbosacral junction that can also be used at L4-L5 and L3-L4. The MICA provides access and sufficient intraforaminal visualization for IEDH in the lumbosacral region without resection of stability-relevant structures or manipulation of the nerve root ganglion.

Comparison of Incidence of Adjacent Segment Pathology between Anterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion Treatments for Lumbosacral Junction.

This research compared the incidence of adjacent segment pathology (ASP) between anterior interbody lumbar fusion (ALIF) treatment and transforaminal lumbar interbody fusion (TLIF) treatment. Seventy patients were included in this retrospective study: 30 patients received ALIF treatment, and 40 patients received TLIF treatment at a single medical center between 2011 and 2020 with a follow-up of at least 12 months. The outcomes were radiographic adjacent segment pathology (RASP) and clinical adjacent segment pathology (CASP). The mean follow-up period was 42.10 ± 22.61 months in the ALIF group and 56.20 ± 29.91 months in the TLIF group. Following single-level lumbosacral fusion, ALIF is superior to TLIF in maintaining lumbar lordosis, whereas the risk of adjacent instability in the ALIF group is significantly higher. Regarding ASP, the incidence of overall RASP and CASP did not differ significantly between ALIF and TLIF groups.

The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine.

The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine.

Effect of osteopathic manipulation on gait asymmetry.

Movement and loading asymmetry are associated with an increased risk of musculoskeletal injury, disease progression, and suboptimal recovery. Osteopathic structural screening can be utilized to determine areas of somatic dysfunction that could contribute to movement and loading asymmetry. Osteopathic manipulation treatments (OMTs) targeting identified somatic dysfunctions can correct structural asymmetries and malalignment, restoring the ability for proper compensation of stresses throughout the body. Little is currently known about the ability for OMTs to reduce gait asymmetries, thereby reducing the risk of injury, accelerated disease progression, and suboptimal recovery. To demonstrate whether osteopathic screening and treatment could alter movement and loading asymmetry during treadmill walking. Forty-two healthy adults (20 males, 22 females) between the ages of 18 and 35 were recruited for this prospective intervention. Standardized osteopathic screening exams were completed by a single physician for each participant, and osteopathic manipulation was performed targeting somatic dysfunctions identified in the screening exam. Three-dimensional (3-D) biomechanical assessments, including the collection of motion capture and force plate data, were performed prior to and following osteopathic manipulation to quantify gait mechanics. Motion capture and loading data were processed utilizing Qualisys Track Manager and Visual 3D software, respectively. Asymmetry in the following temporal, kinetic, and kinematic measures was quantified utilizing a limb symmetry index (LSI): peak vertical ground reaction force, the impulse of the vertical ground reaction force, peak knee flexion angle, step length, stride length, and stance time. A 2-way repeated-measures analysis of variance model was utilized to evaluate the effectsof time (pre/post manipulation) and sex (male/female) on each measure of gait asymmetry. Gait asymmetry in the peak vertical ground reaction force (-0.6%, p=0.025) and the impulse of the vertical ground reaction force (-0.3%, p=0.026) was reduced in males following osteopathic manipulation. There was no difference in gait asymmetry between time points in females. Osteopathic manipulation did not impact asymmetry in peak knee flexion angle, step length, stride length, or stance time. Among the participants, 59.5% (25) followed the common compensatory pattern, whereas 40.5% (17) followed the uncommon compensatory pattern. One third (33.3%, 14) of the participants showed decompensation at the occipitoatlantal (OA) junction, whereas 26.2% (11), one third (33.3%, 14), and 26.2% (11) showed decompensation at the cervicothoracic (CT), thoracolumbar (TL), and lumbosacral (LS) junctions, respectively. Somatic dysfunction at the sacrum, L5, right innominate, and left innominate occurred in 88.1% (37), 69.0% (29), 97.6% (41), and 97.6% (41) of the participants, respectively. Correcting somatic dysfunction can influence gait asymmetry in males; the sex-specificity of the observed effects of osteopathic manipulation on gait asymmetry is worthy of further investigation. Osteopathic structural examinations and treatment of somatic dysfunctions may improve gait symmetry even in asymptomatic individuals. These findings encourage larger-scale investigations on the use of OMT to optimize gait, prevent injury and the progression of disease, and aid in recovery after surgery.

Lumbosacral Transitional Vertebrae in patients attending a Tertiary Care Hospital of Nepal

Introduction: Lumbosacral Transitional vertebrae are congenital anomalies of lumbosacral vertebral junction. It may present either as sacralization of fifth lumbar vertebrae or lumbarization of first sacral vertebrae. Various secondary pathological spinal conditions such as intervertebral disc herniation and/or degeneration, facet joint arthrosis and spinal canal or foraminal stenosis are associated with the presence of LSTV. The failure in the identification may lead to clinical consequences such as errors in diagnosis of disease and lumbosacral procedures.&#x0D; Objective: The aim of this study was to determine the prevalence and patterns of LSTV in patients presenting to Department of Radiology of Nobel Medical College Teaching Hospital, Nepal..&#x0D; Methodology: A descriptive cross-sectional study was conducted in Department of Radiology of Nobel Medical College Teaching Hospital, Nepal.Plain radiographs including Antero-posterior (AP) and Lateral views of lumbosacral spine of 343 patients referred for the scan were analyzed for the presence of lumbosacral vertebrae.&#x0D; Result: Out of 343 patients, LSTV was found in 61 (17.8%) subjects. Thirty-eight subjects (11.1%) exhibited sacralization and 23 (6.7%) showed lumbarization.Out of total LSTV subjects, type I A was present in 8 (13.1%), type I B in 21 (34.4%), type II A in 10 (16.4%), type II B in 5 (8.2%) , type III A in 6 (9.8%) , type III B in 9 (14.8%) and type IV in 2 (3.3%).&#x0D; Conclusion: The LSTV is prevalent in almostone-fifth of subjects presenting to department of radiology of Nobel Medical College and Teaching Hospital, Biratnagar for lumbosacral scan.. Sacralization occurs more frequently than lumbarization, both of which alter the morphology of anatomical structures in spine. The presence of anomaly in this region may be related to occurrence of various pathological and clinical conditions.

Multiple-Rod Constructs Do Not Reduce Pseudarthrosis and Rod Fracture After Pedicle Subtraction Osteotomy for Adult Spinal Deformity Correction but Improve Quality of Life.

ObjectiveTo compare the radiological and functional outcomes and complications of adult spinal deformity patients who underwent a pedicle subtraction osteotomy (PSO) below L2 but categorized according to their construct where either 2-rod or multiple-rod construct is applied. MethodsSixty-seven patients met the inclusion criteria, and were categorized into 3 groups: 2 rods (2R), multiple rods around the PSO (MRP), multiple rods around the PSO and lumbosacral junction (MRL). Demographic data, operative parameters, spinopelvic parameters, functional outcomes, and complications were collected. ResultsHealth-related quality of life scores showed a better outcome at 6 months and last follow-up visits in the MRP and MRL groups which were noted on different domains of Scoliosis Research Society-22 questionnaire, 36-item Short Form Health Surve, and Oswestry Disability Index scores (p<0.05). The 3 groups showed similar rates of rod-related complications with no significant difference (p=0.95). And inside each group, distribution of complications between pseudarthrosis with revision and rod fracture without revision was also similar (p=0.99). ConclusionThe use of multiple rods across the PSO did not show a better outcome when compared to single rods in terms of incidence and types of mechanical complications. However, better postoperative coronal alignment and health-related quality of life scores in the multiple rods group could be seen demonstrating an improved functional outcome.

Performing Lumbosacral Transdiscal Fixation: The Boachie Screw Technique.

Transdiscal screw fixation through the Boachie screw technique at the lumbosacral junction is a well-accepted procedure in the treatment of high-grade spondylolisthesis. This technique allows for partial reduction of the spondylolisthesis, decompression of the neural elements, and reliable posterior lumbosacral fixation. When performed properly, this procedure produces reliable results and high rates of arthrodesis with relief of preoperative neurological symptoms.

Spinal Manifestation of Malignant Primary (PLB) and Secondary Bone Lymphoma (SLB).

Manifestation of malignant lymphoma in the spine is rare; there have only been a few cases reported in the literature. Due to its rarity, there is no gold standard for the management of patients suffering from spinal lymphoma manifestations. Methods: We retrospectively reviewed the data for 37 patients (14 female, 23 male) with malignant lymphoma in the spine receiving intervention in our center from March 2006 until June 2020. Neurological impairment, pain, diagnostics, and/or surgical instability were the criteria for surgery in this patient cohort. Otherwise, only CT-guided biopsies were conducted. Analysis of the patient cohort was based on the Karnofsky performance status scale (KPSS), location of the lesion, spinal levels involved, spinal instability neoplastic score (SINS), surgical treatment, histopathological workup, adjuvant therapy, and overall survival. The following surgical procedures were performed: posterior stabilization and decompression in nine patients; decompression and/or tumor debulking in 18 patients; a two-staged procedure with dorsal stabilization and vertebral body replacement in four patients; decompression and biopsy in one patient; a two-stage procedure with kyphoplasty and posterior stabilization for one patient; posterior stabilization without decompression for one patient; a vertebroplasty and cement-augmented posterior stabilization for one patient; and a CT-guided biopsy alone for two patients. Twenty-one patients (56.78%) had ≥1 lesion in the thoracic spine, 10 patients (27.03%) had lesions in the lumbar spine, two patients had lesions in the cervicothoracic junction, two patients had lesions in the thoracolumbar junction, one patient had a lesion in the lumbosacral junction, and one patient had a lesion in the sacrum. The diagnoses of the histopathological workup were diffuse large B-cell lymphoma in 23 (62.16%) cases, indolent lymphoma in 11 (29.74%) cases, anaplastic T-cell lymphoma in one case (2.70%), T-cell lymphoma in one case (2.70%), and Burkitt lymphoma in one (2.70%) case. The median overall survival was 7.2 months (range 0.1–266.7 months). Pre- and postoperative KPSS scores were 70% (IQR 60–80%). Manifestation of malignant lymphomas in the spine is rare. Similar to the approach taken for spine metastases, a surgical intervention in cases of neurological impairment or manifest or potential instability is indicated, followed by chemoimmunotherapy and radiotherapy.

Utilization of S1 Foraminal Hooks for Augmentation of S1 Screws in Adult Spinal Deformity Surgery: Comparative Study With Iliac Screws.

ObjectiveTo compare the outcomes of S1 foraminal hooks and iliac screws regarding fusion rate at the lumbosacral junction and protective effects on S1 screws. MethodsFrom January 2017 to December 2019, consecutive patients who underwent long fusions (uppermost instrumented vertebra at or above L1) to the sacrum for adult spinal deformity were enrolled. Patients were divided into S1 foraminal hook group and iliac screw group. Radiographic parameters and the incidence of pseudarthrosis and instrument failure at the lumbosacral junction were compared between the groups. ResultsTwenty-nine patients (male:female = 1:28) with a mean age of 73.6±6.8 years were evaluated. Sixteen patients (55.2%) had S1 foraminal hook fixation and 13 patients (44.8%) had iliac screw fixation. Lumbar lordosis, sacral slope, and sagittal vertical axis did not differ between the groups preoperatively and postoperatively. The rate of L5/S1 pseudarthrosis was significantly higher in S1 foraminal hook group (5 of 16, 31.3%), compared to iliac screw group (0 of 13, 0%; p=0.048). Instrument failure at the lumbosacral junction trended toward a higher rate in S1 foraminal hook group (6 of 16, 37.5%) than in iliac screw group (1 of 13, 7.7%), without statistical significance (p=0.09). Proximal junctional kyphosis/failure occurred less often in S1 foraminal hook group (2 of 16, 12.5%) than in iliac screw group (3 of 13, 30.8%) without statistical significance (p=0.36). ConclusionTreatment with S1 foraminal hooks achieved equivalent satisfactory sagittal correction with proportioned alignment compared to that with iliac screws. However, S1 foraminal hooks did not provide enough structural support to the lumbosacral junction in long fusions to the sacrum.

Medium-Term Follow-Up Outcomes of One-Stage Posterior Lumbosacral or Lumbopelvic Fixation in the Management of Lumbosacral Junction Tuberculosis in Adults.

ObjectiveTo evaluate the medium‐term outcomes of one‐stage posterior lumbosacral or lumbopelvic fixation treatment of lumbosacral junction tuberculosis in adults.MethodsThis retrospective study enrolled a total of 38 adult patients (24 males and 14 females) with an average age of 48.0 ± 13.0 years (range, 25–75 years) during the period from February 2008 to July 2015. All patients were treated by one‐stage posterior debridement, interbody fusion, lumbosacral or lumbopelvic fixation, and postural drainage. After pedicle screw or iliac screw fixation, a hemi‐laminectomy or laminectomy was performed on the severely damaged side of the lesion segment. Intervertebral bone grafting and intertransverse bone grafting were performed after clearing the focus of tuberculosis. All cases were followed up for at least 5 years. Intraoperative blood loss, operative time, erythrocyte sedimentation rate (ESR), pain intensity was assessed by visual analog scale (VAS) score; neurological function was assessed by Japanese Orthopaedic Association (JOA) score; quality of life was assessed by Oswestry Disability Index (ODI); functional outcome, lumbosacral angle, and fusion time were gathered and analyzed. All data expressed as mean ± standard deviation.ResultsDuring the 66.2 ± 4.4 months (range, 60–78 months) follow‐up, all patients achieved clinical cure without severe complications. The intraoperative blood loss was 726.3 ± 151.9 mL (range, 400–1100 mL) and the operative time was 137.6 ± 22.5 min (range, 110–200 min). The ESR decreased to normal levels within (11.8 ± 2.6 mm/h) 3 months postoperatively. The VAS score significantly decreased from 6.8 ± 1.1 preoperatively to 0.8 ± 0.7 at the final follow‐up (P < 0.01). The mean JOA improved from preoperative 18.5 ± 2.9 to 26.9 ± 1.1 at the last visit (P < 0.01). The mean ODI was 44.3 ± 6.7 and significantly decreased to 9.3 ± 1.9 at the final observation (P < 0.01). Patient‐reported outcomes as measured by Kirkaldy‐Willis criteria were excellent in 21 cases, good in 16 cases, and fair in one case; there were no poor outcomes. Lumbosacral angle increased from the preoperative values of 21.7° ± 1.8° to the postoperative values of 26.4° ± 1.4° (P < 0.01), with an angle loss of 1.2° ± 0.7° at the last follow‐up. Bone fusion occurred on average 12.8 ± 1.9 months (range, 9–15 months) after surgery. No nonunion, pseudarthrosis, loosening or fracture of instruments occurred at the last follow‐up.ConclusionOne‐stage posterior debridement, interbody fusion, lumbosacral or lumbopelvic fixation, and postural drainage according to the severity of sacral destruction is an effective and highly safe procedure to treat lumbosacral junction tuberculosis in adults.

216. Does interbody fusion at L4-L5 and L5-S1 lead to a lower rate of revision surgery for pseudarthrosis and rod fracture at the lumbosacral junction?

<h3>BACKGROUND CONTEXT</h3> Pseudarthrosis and rod fracture at the lumbosacral junction can lead to pain and loss of deformity correction requiring complex revision surgery. Multiple rods spanning the lumbosacral junction and interbody fusion may minimize the risk for pseudarthrosis and instrumentation failure. It remains unclear if interbody fusion at the caudal levels of a long fusion reduces long-term complications. <h3>PURPOSE</h3> To evaluate rates of revision for pseudarthrosis and rod fracture with interbody fusion at L4-L5 and L5-S1, compared to PSF only in long fusion constructs for adult spinal deformity (ASD) surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected single center database. <h3>PATIENT SAMPLE</h3> This study included 367 ASD patients (age: 58 ± 16 y; mFI: .6 ± .7; levels fused: 10.1 ± 4.8) with mean follow-up 68.1 months. <h3>OUTCOME MEASURES</h3> Outcomes evaluated were the rates of revision surgery for pseudarthrosis or rod fracture at the lumbosacral junction. <h3>METHODS</h3> A total of 367 ASD patients were divided into two groups: PSF only (PSF, n=192), and ALIF or TLIF (interbody fusion [IBF], n=175). Patient and surgical characteristics were assessed. Radiographic criteria were evaluated for association with incurrence of pseudarthrosis or rod fracture. <h3>RESULTS</h3> There was no significant difference in patient comorbidities. Estimated blood loss (EBL) was significantly greater in the IBF group (2.4 L vs 1.6 L, p<0.0001). Titanium interbody devices were used in 79.2% of cases and 5.5 mm cobalt chrome rods in 86.4%. There were no differences in BMP utilization. At final follow-up there was no difference in correction of SVA (PSF, IB) (20.5 mm, 32.2 mm, p=0.13), coronal alignment (5.3 mm, 6.7 mm, p=0.65), or lumbar lordosis (6.9°, 9.9°, p=0.29) compared to preoperative baseline. There was no difference in rates of rod fracture at the lumbosacral junction (13.5%, 17.7%, p=0.27), or revision surgery for L4-L5 or L5-S1 pseudarthrosis (7.3%, 10.9%, p=0.23), sagittal malalignment (3.1%, 0.5%, p=0.07), or PJK (4.2%, 6.3%, p=0.36). There was no difference in the rate of neurologic complications between the two groups (19.8%, 28%, p=0.17), or rate of revision surgery for neurologic complications (3.1%, 4.6%, p=0.47). <h3>CONCLUSIONS</h3> At long-term follow-up in a cohort of single institution patients, there were no differences in maintenance of deformity correction, or revision rates for rod fracture, pseudarthrosis, PJK, or neurologic complications when interbody fusion was utilized. The utilization of interbody technique at the lumbosacral junction is not clearly superior to posterior fusion only. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P101. Pseudarthrosis and rod fracture at the distal levels of a long construct are associated with proximal junctional kyphosis after ASD surgery

<h3>BACKGROUND CONTEXT</h3> More distal fusion levels and overall stiffness of a long fusion construct for ASD may result in larger range of motion and stress at the proximal junctional level. Stability of distal fixation, inferred by the presence or absence of pseudarthrosis and rod fracture, may affect proximal junctional stresses and contribute to proximal junctional kyphosis (PJK) and associated revision surgery.To date, very few studies have evaluated the relationship between achieving solid fusion at the base of a long construct and rate of PJK. <h3>PURPOSE</h3> To assess the relationship between lumbosacral rod fracture and pseudarthrosis and development of proximal junctional kyphosis (PJK) after long construct ASD surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected single center database. <h3>PATIENT SAMPLE</h3> We performed a review of 942 patients who underwent ASD surgery (Age: 55 ± 23 y; mFI: .41 ± .67; Levels fused: 10.1 ± 4.2; Revision: 22.3%; 3CO: 12.3%). <h3>OUTCOME MEASURES</h3> We assessed the rate of PJK at minimum 2-year follow-up, as well as the rate of pseudarthrosis or rod fracture at the lower lumbar levels or lumbosacral junction, and the association between these complications. <h3>METHODS</h3> A total of 942 patients were divided into PJK and non-PJK groups using whole spine standing radiographs. The incidences of PJK, and lumbar or lumbosacral pseudarthrosis were defined. The relationship between these complications was assessed. <h3>RESULTS</h3> The cohort had sagittal malalignment as demonstrated by PT 23.7 ± 12.4°, TPA 22.5 ± 26.2°, and SVA 77.8 ± 70 mm. The PJK and non-PJK groups comprised 350 and 592 cases respectively. Mean follow-up time was 48.9 months. There was no significant difference in baseline SVA, T1 pelvic angle, change in sagittal alignment postoperatively, and surgical invasiveness index between the two groups. There were 11.1% of patients who developed PJK had a pseudarthrosis at the lower lumbar levels or lumbosacral junction, versus 6.4% of those who did not develop PJK (p=0.011). Patients who developed PJK had a significantly higher rate of rod fracture in the lower lumbar levels or lumbosacral junction (15.4%) versus those who did not develop PJK (7.3%) (p<0.0001). Pseudarthrosis (OR: 1.963, 95% CI: 1.14-3.38, p=0.015) and rod fracture at the lower lumbar levels or lumbosacral junction (OR: 2.27, 95% CI: 1.41-3.64, p=0.001) were predictors of PJK at final follow-up by regression analysis. <h3>CONCLUSIONS</h3> Pseudarthrosis and rod fracture at the lower lumbar levels or lumbosacral junction were predictive of development of PJK at final follow-up. This may indicate that distal stability of a long construct has a significant impact on stresses at the proximal junction. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Lumbosacral transitional vertebra in military aviation candidates: A cross-sectional study

Introduction: Lumbosacral transitional vertebra (LSTV) is a common anomaly of the lumbosacral junction with a prevalence of 4–35.9% in various studies. Plain radiography of the spine in anteroposterior and lateral projections is done for the evaluation of the spine in candidates coming for medical evaluation for flying duties in the armed forces. Material and Methods: An observational study was conducted on the whole spine series of radiographs done at a medical selection establishment. The study population included candidates reporting to the establishment for medical examination to ascertain fitness for flying duties. In a small subset of this study population having LSTV, the Ferguson’s view was done to better delineate the lumbosacral junction. Results: The analysis revealed a total 148 cases of LSTV with a prevalence of 13.9%. Ferguson’s view, undertaken among 30 doubtful cases, confirmed the presence of LSTV in 27 cases. Type IIa was observed to be the most common pattern of LSTV followed by Type IIIb. As per the existing policy, 63.8% of candidates with LSTV were considered unfit for flying duties. Conclusion: Flying duties in the armed forces require the highest standard of physical fitness. LSTV is a very common finding during the evaluation of candidates and it is appropriate that the cases of LSTV be evaluated thoroughly. In doubtful cases of LSTV, the Ferguson’s view is a useful supplementary view as it clearly delineates the lumbosacral junction.

HIGH GRADE DYSPLASTIC SPONDYLOLISTHESIS IN AN 11 YEAR OLD GIRL CHILD - A CASE REPORT

High-Dysplastic Developmental Spondylolisthesis (HDDS) is an extremely rare situation, comprising of around 5% of the total cases of spondylolisthesis. Clinical Description :- A eleven year-old girl with high-grade dysplastic L5-S1 spondylolisthesis with pain in her lower back along with radicular pain to her lower limbs (right &gt; left). Her X-rays depicted a L5 - S1 anterolisthesis leading to an abnormal kyphosis at lumbo-sacral junction, increased lumbar lordosis and reversal of thoracic kyphosis to lordosis. Management:- A was done along with a cage insertion at the L5 - S1 level. L5 - S1 posterior - spinal fixation Outcome:- Postural correction was achieved immediately post-op and the patient also had relief from the radicular symptoms.

Implant-Related Complications Using Uniaxial Implants In Pediatric Spinal Deformity Surgery.

Introduction: The successful surgical treatment of paediatric spinal deformity relies on robust anchors to achieve correction. Uniaxial pedicle screws are designed with articulation between the screw head and screw shaft, thus reducing the risk of anchor failure whilst permitting corrective manoeuvres. The purpose of this study was to describe the incidence, nature, and chronology of implant-related complications in pediatric spinal deformity treated with uniaxial pedicle screws.Methods: A retrospective radiographic analysis was carried out on paediatric patients treated for spinal deformity with more than two years of follow-up. Each was treated with posterior instrumented spinal fusion (PISF) using a uniaxial pedicle screw system by a single surgeon at a single institution. Surgical records, post-operative radiographs, and follow-up documentation were scrutinised for details of the implants used, implant failure, and revision procedures.Results: Three hundred and eighty-nine eligible patients with a mean follow-up of 3.3 years were identified. The mean anchor density was 1.7. Seven implant complications were observed. Early complications (<12 months) occurred in four cases and late (>12 months) in three cases. None of the early complications were associated with non-union. Two early and two late complications required revision surgery to manage implant failure and non-union. Patients who underwent fusion across the lumbosacral junction showed a higher than expected rate of implant-related complication (P=0.02).Conclusion: This study shows that there is a rate of implant-related failure of 1.8% after PISF with uniaxial implants in pediatric spinal deformities. There is a distinction between early and late implant-related complications, with early failure being due to loss of construct integrity, whereas late failure is due to pseudarthrosis and construct fatigue.