Posterior Pedicle Screw Instrumentation Research Articles

What is the early fate of adjacent segmental lordosis compensation at L3-4 and L5-S1 following a lateral versus transforaminal lumbar Interbody Fusion at L4-5?

Degenerative spondylolisthesis causes translational and angular malalignment, resulting in a loss of segmental lordosis. This leads to compensatory adjustments in adjacent levels to maintain balance. Lateral lumbar interbody fusion (LLIF) and transforaminal lumbar interbody fusion (TLIF) are common techniques at L4-5. This study compares compensatory changes at adjacent L3-4 and L5-S1 levels six months post LLIF versus TLIF for grade 1 degenerative spondylolisthesis at L4-5. A retrospective study included patients undergoing L4-5 LLIF or TLIF with posterior pedicle screw instrumentation (no posterior osteotomy) for grade 1 spondylolisthesis. Pre-op and 6-month post-op radiographs measured segmental lordosis (L3-L4, L4-L5, L5-S1), lumbar lordosis (LL), and pelvic incidence (PI), along with PI-LL mismatch. Multiple regressions were used for hypothesis testing. 113 patients (61 LLIF, 52 TLIF) were studied. TLIF showed less change in L4-5 lordosis (mean = 1.04°, SD = 4.34) compared to LLIF (mean = 4.99°, SD = 5.53) (p = 0.003). L4-5 angle changes didn't correlate with L3-4 changes, and no disparity between LLIF and TLIF was found (all p > 0.16). In LLIF, greater L4-5 lordosis change predicted reduced compensatory L5-S1 lordosis (p = 0.04), while no significant relationship was observed in TLIF patients (p = 0.12). LLIF at L4-5 increases lordosis at the operated level, with compensatory decrease at L5-S1 but not L3-4. This reciprocal loss at adjacent L5-S1 may explain inconsistent improvement in lumbar lordosis (PI-LL) post L4-5 fusion.

Early Compensatory Segmental Angle Changes at L3-L4 and L4-L5 After a L5-S1 Interbody Fusion for a Grade 1 Spondylolisthesis.

The retrospective study included patients who underwent an L5-S1 anterior (ALIF) or transforaminal (TLIF) lumbar interbody fusion with posterior pedicle screw instrumentation for grade 1 spondylolisthesis from 2018 to 2022. To compare early reciprocal changes at the L3-L4 and L4-L5 adjacent levels 6 months after ALIF or TLIF at L5-S1. Degenerative and chronic isthmic spondylolistheses often result in decreased segmental lordosis (SL) at L5-S1. This can lead to lordotic overcompensation at adjacent levels to maintain spinopelvic balance. However, the fate of adjacent angles after interbody fusion is not well understood. Preoperative and 6-month postoperative measurements of SL (L3-L4, L4-L5, and L5-S1), lumbar lordosis, and pelvic incidence (PI) were obtained from sagittal standing radiographs. Preliminary t tests were performed for descriptive purposes, and multiple regression was used for hypothesis testing. Ninety-eight patients met the inclusion criteria (50 ALIF and 48 TLIF). A greater amount of lordosis achieved at L5-S1 was significantly associated with a greater reduction of SL at L4-L5 ( r = -0.65, P < 0.001) or L3-L4 ( r = -0.46, P < 0.001). A greater preoperative PI was associated with a greater reduction of SL at L4-L5 ( r = -0.42, P < 0.001) and at L3-L4 ( r = -0.44, P < 0.001). At 6 months after a lumbar interbody fusion at L5-S1, greater compensatory changes with lordosis reduction are observed at the supra-adjacent L4-L5 and L3-L4 levels in patients achieving greater L5-S1 SL. In addition, preoperative PI played a role in influencing lordotic correction.

Back Pain and Quality of Life 10 Years After Segmental Pedicle Screw Instrumentation for Adolescent Idiopathic Scoliosis.

Comparative cohort study. The aim of the present study was to evaluate pain and health-related quality of life (HRQoL) in surgically managed patients with a minimum follow-up of 10 years compared with patients with untreated adolescent idiopathic scoliosis (AIS) and a healthy control group. Posterior spinal fusion with pedicle screws is the standard treatment for AIS, although it remains unclear whether this procedure results in improved long-term HRQoL compared with untreated patients with AIS. Sixty-four consecutive patients at a minimum follow-up of 10 years, who underwent posterior pedicle screw instrumentation for AIS were prospectively enrolled. Fifty-three (83%) of these patients completed Scoliosis Research Society (SRS) 24 questionnaires, clinical examination, and standing spinal radiographs. Pain and HRQoL were compared with age and sex-matched patients with untreated AIS and healthy individuals. The mean major curve was 57° preoperatively and 15° at the 10-year follow-up. SRS-24 self-image domain score showed a significant improvement from preoperative to 2 years and remained significantly better at the 10-year follow-up ( P < 0.001). Patients fused to L3 or below had lower pain, satisfaction, and total score than patients fused to L2 or above ( P < 0.05), but self-image, function, and activity scores did not differ between groups at 10-year follow-up. Pain, self-image, general activity, and total SRS domains were significantly better at 10-year follow-up in the surgically treated patients as compared with untreated patients (all P < 0.05). Healthy controls had significantly higher total score s than those surgically treated at 10-year follow-ups ( P < 0.001). Patients undergoing segmental pedicle screw instrumentation for AIS maintain high-level HRQoL during a 10-year follow-up. Their HRQoL was significantly better than in the untreated patients with AIS, except for the function domain. However, HRQoL remained at a lower level than in healthy controls.

Acceptable Fusion Rate of Single-Level OLIF Using Pure Allograft Combined with Posterior Instrumentation through the Wiltse Approach: A 2-Year Follow-Up Study.

Autogenic bone grafts have shown successful fusion rates in the treatment of degenerative lumbar disorders, but taking too many autogenic bones may result in donor site ischemia or infection. This study aimed to evaluate the outcomes of single-level oblique lumbar interbody fusion (OLIF) using pure allograft combined with posterior pedicle screw instrumentation through the Wiltse approach. A retrospective case analysis was performed on a series of consecutive patients who received a single-level OLIF procedure combined with posterior pedicle screw instrumentation through the Wiltse approach between July 1, 2017, and December 31, 2019, in which pure allogenic bone graft was used and filled in the large window of the cage. The patients were followed up as scheduled at 1 day and 3, 6, 12, 24months after operation. Clinical outcome was assessed by multiple questionnaires, including Oswestry disability index (ODI), Japanese Orthopaedic Association (JOA) score rating system, short form-36 health survey (SF-36), and visual analog scale (VAS) for low back pain. Radiographic outcome was evaluated by measuring the parameters such as disc height, lumbar lordosis, and segmental angle on the standard standing lateral radiographs, and the space angle of the fusion level on the dynamic views of the lateral radiographs. Subsidence of the cage and intervertebral fusion status were evaluated on both the radiographic and CT scan images. A total of 34 patients were finally included in this study. At 2-year follow-up, the VAS for low back pain, ODI, JOA, and SF-36 scores all had significant improvement (p < 0.001). Substantial increase of anterior and posterior disc heights was observed (p < 0.001). Both lumbar lordosis and segmental angle became larger (p < 0.05). No visible change of the space angle of the fusion level was found on the dynamic views. The 1-year fusion rate of 73.5% on CT scans proceeded to 82.4% at 2-year follow-up. The fusion rate was as high as 91.2% according to Bridwell interbody fusion grading system on radiographic images. The clinical outcomes in patients with incomplete fusion were just as good as those with complete fusion. The six patients with cage subsidence had higher ODI (p < 0.001) and lower JOA (p < 0.001) and SF-36 PCS (p=0.011) scores than those without cage subsidence. The use of pure allograft in single-level OLIF resulted in an acceptable fusion rate and satisfactory clinical effect at 2-year follow-up. Supplementation of posterior pedicle screw through the minimally invasive Wiltse approach ensured the favorable outcomes both clinically and radiographically.

The effects of pre-stressed rods contoured by different bending techniques on posterior instrumentation of L4-L5 lumbar spine segment: A finite element study.

Posterior pedicle screw instrumentation (PPSI) is a well-known method in lumbar spine surgery. Understanding how PPSI affects the biomechanics of the lumbar spine is an important issue. In particular, during PPSI operations, surgeons bend rods according to the patients' spinal curvatures based on their own experiences. As a result, residual stresses develop on the rods due to this bending. Although many finite element-based biomechanical studies have been performed for PPSI, studies comparing the effects of residual stresses arising from rod contouring on the construct stresses are lacking. Thus, this study aimed to investigate the effects of residual stress in PPSI using rods contoured with a French bender and an in-situ bender, as well as comparing the differences in stress increment with straight and contoured rods for different physiological motions. Accordingly, a finite element (FE) model of the L4-L5 lumbar spine segment was developed for PPSI and the effects of residual stresses on rods were investigated by using different bending methods. In the simulations, it was found that rods contoured with a French bender with residual stress resulted in significantly more increased stress in PPSI compared to those contoured with an in-situ bender. The results of this study emphasize that increased stress in PPSI due to the residual stresses for different physiological motions may increase the risk of PPSI failures. Additionally, the finite element modeling approach employed here could be used as a fundamental tool for further investigations of topics such as PPSI fatigue life and failure studies.

Dual-Rod Instrumentation Via the Anterior Approach for Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis

Background: Posterior spinal fusion with pedicle screw instrumentation is currently the standard technique for spinal surgery. However, the anterior approach remains useful for thoracolumbar and lumbar (TL/L) lesions, such as in adolescent idiopathic scoliosis (AIS) 1–4 and spinal injuries 5,6 . We previously documented that long-term radiographic findings and clinical measures were satisfactory in patients with TL/L AIS treated with anterior dual-rod instrumentation 1 . Description: This surgical technique is indicated for single TL/L (Lenke 5) curves and is performed with use of extrapleural retroperitoneal approaches. The extrapleural cavity is connected to the retroperitoneal space by diaphragmatic transection. The lateral aspect of the vertebral bodies is exposed by retracting the psoas major muscle posteriorly from the intervertebral discs. Segmental vascular bundles are divided with coagulation and/or ligation. Care should be taken to reflect the psoas in its entirety and avoid an intramuscular approach to prevent bleeding injury to nerves, including the femoral, ilioinguinal, and genitofemoral nerves, as well as ureteral injury. After the intervertebral discs and cartilage plates are removed to the vertebral end plates, 2 screws are inserted in each vertebral body through a vertebral staple 1,4 . The anterior rod is then placed in the screw heads and rotated anteriorly, providing 3-dimensional correction of kyphotic deformities with lordosis production 1,4 . After the posterior rod is applied in the same manner as the anterior rod, compression forces are applied between the screws to correct scoliosis 1,4 . The compression force is first applied to the posterior rod so that kyphosis can be corrected more effectively 1,4 . Alternatives: Posterior pedicle screw instrumentation techniques are widely utilized for TL/L AIS curve correction. However, anterior techniques have frequently also been applied to the curve. Dwyer et al. 7 first reported the use of anterior spinal fusion (ASF) with a single braided cable connecting vertebral screws for the treatment of TL/L AIS, and Zielke et al. 8 modified that procedure by replacing the cable with a threaded rod. Although these instrumentation techniques and other single anterior rod techniques such as the Texas Scottish Rite Hospital System effectively correct scoliosis in the coronal plane and improve vertebral derotation 1,9 , poor sagittal and rotational plane deformity correction, implant weakness, and high incidence of pseudarthrosis remain unresolved issues 1 . Rationale: The fundamental advantages of the anterior approach in dual-rod instrumentation are the ability to achieve 3-dimensional correction with extremely low rates of pseudarthrosis and implant failure 1,10–12 . Furthermore, the fusion is expected to include fewer motion segments than with posterior systems (usually 1 level less distally and proximally). However, low skeletal maturity and a TL/L to thoracic Cobb ratio of &lt;1.25 appeared to be important factors for postoperative curve progression of the thoracic coronal deformity following ASF for the treatment of Lenke 5 curves 1,13 . In addition, subjacent disc wedging may occur when the subjacent disc is nearly parallel before surgery 1,14 . Expected Outcomes: The described technique is expected to provide 3-dimensional spinal correction. In a previous study, 30 patients with Lenke 5 AIS were followed for a mean of 17 years 1 . The mean TL/L Cobb angle correction rate and correction loss were 79.8% and 3.4°, respectively, at the time of the latest follow-up 1 . The average percent of predicted forced vital capacity and of forced expiratory volume in 1 second were 91.8% and 81.8%, respectively 1 . The average total score on the Scoliosis Research Society-30 outcome instrument was 4.21. No instrumentation failure, pseudarthrosis, or clinically relevant neurovascular complications were observed 1 . Important Tips: This technique is applicable to Lenke 5 AIS curves. However, the anterior approach can also be utilized for other TL/L lesions.The anterior procedure is accomplished via extrapleural retroperitoneal approaches with diaphragmatic transection.Care should be taken to reflect the psoas in its entirety and avoid an intramuscular approach to prevent bleeding and nerve and ureteral injuries. Acronyms &amp; Abbreviations: SRS-30 = Scoliosis Research Society-30

Does Interbody Support at L5-S1 Matter in Long Fusions to the Pelvis?: A 5-year Analysis.

Retrospective review of prospectively collected data. To determine if the addition of L5-S1 interbody support in long fusion deformity constructs is associated with superior long-term clinical and radiographic outcomes. To compare the 5-year clinical and radiographic outcomes and complications between long fusion constructs with L5-S1 interbody support versus posterolateral fusion (PLF) alone. Cadaveric biomechanical studies have suggested that an interbody fusion at L5-S1 is beneficial in long fusion constructs with sacropelvic fixation. However, there is limited data reflecting the superiority of interbody support augmentation in optimizing arthrodesis and deformity correction relative to PLF alone. Eighty-eight consecutive adults with spinal deformity who underwent at minimum T11-pelvis posterior pedicle screw instrumentation with 5-year follow-up were included. Two cohorts were compared based on technique used at the lumbosacral junction (L5-S1): (A) no interbody (PLF; n = 23), or (B) interbody support at L5-S1 (IB; n = 65). Radiographic measurements and clinical outcome measures were compared at multiple time points. Complications were recorded and compared. No differences in baseline patient characteristics between cohorts. One nonunion occurred at L5-S1 in the PLF group (P = 0.091). Initial postop sagittal alignment was better in the IB group (PLF: 6.46 cm, IB: 2.48 cm, P = 0.007); however, this was not maintained over long-term follow-up. No significant differences in proximal junctional kyphosis (PLF: 7/23, IB: 9/65, P = 0.076). Proximal junctional failure was more frequent in the PLF group (PLF: 6/23, IB: 6/65, P = 0.043). No significant differences in complications were found. Both cohorts had improvement from baseline pain and functional scores. There is no absolute long-term advantage for lumbar interbody support in adult spinal deformity patients undergoing spinal arthrodesis to the pelvis.Level of Evidence: 3.

37. Outpatient minimally invasive lumbar fusion using multimodal analgesic management in the ambulatory surgery setting

BACKGROUND CONTEXT The transition of minimally invasive (MIS) spine surgery from the inpatient to outpatient setting has been aided by advances in multimodal analgesic (MMA) protocols. This clinical case series of patients demonstrates the feasibility of ambulatory MIS transforaminal lumbar interbody fusion (TLIF) and a lateral lumbar interbody fusion (LLIF) procedures while using an enhanced MMA protocol. PURPOSE To present a clinical case series of patients who underwent either a MIS transforaminal lumbar interbody fusion (TLIF) or a lateral lumbar interbody fusion (LLIF) in the ambulatory surgery setting while using an enhanced MMA protocol. STUDY DESIGN/SETTING Retrospective. PATIENT SAMPLE A total of 50 patients who underwent MIS TLIF or LLIF with percutaneous pedicle screw fixation with direct decompression. OUTCOME MEASURES Postoperative pain, postoperative narcotics, postoperative complications. METHODS Consecutive patients who underwent outpatient MIS TLIF or LLIF procedures with percutaneous pedicle screw fixation and direct decompression in the ambulatory setting were reviewed. The procedures were performed using an MMA protocol. The senior surgeon performing the cases had extensive experience, operating in an ambulatory surgical center. Patient demographics and baseline characteristics were recorded, including age, sex, smoking status, Charlson Comorbidity Index (CCI), and body mass index (BMI). Perioperative characteristics, postoperative pain scores and narcotics administered to patients prior to discharge from the ASC were recorded including any complications. RESULTS A total of 50 consecutive patients were identified from September 2016 to July 2019, of which 41 patients (82%) underwent MIS TLIF, and 9 patients underwent MIS LLIF (18.0%). The LLIF procedures involved percutaneous posterior pedicle screw instrumentation and direct tubular posterior decompression. All patients in our study population were discharged home on the day of surgery from the surgical center. The mean length of stay was 4.5±1.6 hours and 3.8±1.6 hours for the TLIF and LLIF cohorts respectively. There was an outlier of 8.8 hours following a TLIF procedure. This patient reported a high VAS pain score of 9 immediately following surgery that needed to be adequately controlled prior to discharge. Our review of medical records revealed no postoperative complications following either the TLIF or LLIF procedures. CONCLUSIONS To our knowledge, the present study of 50 consecutive patients is the largest clinical series of patients who underwent outpatient lumbar fusion procedures in a stand-alone ambulatory surgery setting with no extended postoperative observation capability. Our study of patients who underwent outpatient MIS TLIF or LLIF procedures in the ambulatory surgery setting while using a well-developed multimodal analgesia protocol demonstrated no postoperative complications. Postoperative pain was adequately controlled and all patients were discharged from the ambulatory surgical center on the day of surgery approximately 4.5 (TLIF) and 3.8 (LLIF) hours after the procedure. The findings suggest that with proper preoperative patient selection, an enhanced MMA protocol can lead to discharge of patients from a surgical center and minimize admission to a hospital. Preventing these complications may help increase the likelihood of timely discharge facilitating the performance of lumbar fusion procedures in the ambulatory setting. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Fusions ending above the sagittal stable vertebrae in adolescent idiopathic scoliosis: does it matter?

Retrospective cohort study. To validate whether fusions that end proximal to the sagittal stable vertebrae are at risk for developing distal junctional kyphosis in adolescent idiopathic scoliosis. Posterior spinal fusion is routinely used for the treatment of patients with adolescent idiopathic scoliosis. Fusions that end in either the lower thoracic or upper lumbar spine have the advantage of preserving motion segments. However, fusions ending proximal to the sagittal stable vertebrae has been shown to be at higher risk for developing distal junctional kyphosis. A multi-center database of prospectively enrolled subjects was queried for patients with adolescent idiopathic scoliosis that had Lenke type 1, 2 and 3 curves treated with posterior pedicle screw instrumentation. PA (posterior-anterior) and lateral full-length scoliosis films were obtained on each patient. PA radiographs were viewed to determine the coronal deformity and lateral radiographs to determine the sagittal deformity. Distal junctional kyphosis was defined as a greater than 10° increase in segmental kyphosis between the LIV and the LIV + 1 vertebra. 346 patients were included with 85% being female and mean age of cohort 14.2 [Formula: see text] 2.08years. At 5years postoperatively, there was significant difference occurrence of distal junctional kyphosis dependent on whether the LIV relative to SSV with only 2.2% of fusions below the SSV developing DJK compared to 6.5% for fusions ending at the SSV and 15% for fusions with LIV above the SSV (p < 0.001). There was no statistical difference in revision rates based on the relationship of LIV to SSV. There is an increased risk for development of DJK in patients with AIS treated with posterior fusion where the LIV was chosen proximal to the SSV. Level III.

The Effect of the Lumbar Pedicle and Pediculo-Corporal Junction Histology on the Pedicle Screw Insertion Technique

Background&#x0D; Posterior lumbar pedicle screw instrumentation has gained a wide acceptance in the treatment of the various spinal lesions requiring fusion. Inserting screws into the pedicles take a great deal of skill, as the dense bony parts are not large, and a mistake could push a bone fragment into the spinal nerves, causing pain, loss of mobility and other damage.&#x0D; Aim: To investigate the histological and gross-anatomical properties of the pediculocorporal junction, which can have important clinical implications on the insertion technique of the pedicle screws.&#x0D; Study Design: This study was approved by the University Clinical Center Review Board. Human cadaveric lumbar spinal segments which were fixed with formaldehyde were used in the study.&#x0D; Methods: Twenty pedicles from 10 lumbar spinal segments (L3-L5) were prepared for histological and gross-anatomical investigation. Thin slice cuts were taken from the specimens and examined histologically and macroscopically.&#x0D; Results: There were not any differences in the histological characteristics of the pedicles and the pediculo-corporal junction. Thin compact osseous formation or web like connective tissue formation was not identifiable in the pediculo-corporal junction.&#x0D; Conclusion: All kind of pedicle screws can be attempted to be inserted just after preparation of the insertion point with an awl or just decortication of the entrance point with a rongeur. This can also reduce the pilot hole preparation technique related complications like perforation of the pedicle walls.&#x0D;

The clinical use of the enriched bone marrow obtained by selective cell retention technology in treating adolescent idiopathic scoliosis.

PurposeThis retrospective study aimed to evaluate the curative effect of allografts in combination with bone marrow enrichment realised by selective cell retention (SCR) technology in treating adolescent idiopathic scoliosis (AIS).MethodsFrom July 2014 to September 2016, 18 consecutive patients with AIS were treated by posterior fusion and pedicle screw instrumentation. Bone marrow aspirates were obtained and enriched by SCR technology to fabricate bone grafts in combination with allogeneic bones, which were implanted for spinal fusion. Postoperatively, the patients were observed for a minimum of 18 months, with a mean follow-up period of 48 months. The results were assessed both clinically and radiographically. All adverse events and complications were recorded.ResultsA total of 9 male and 9 female patients were included, with an average age of 15.6 years (range, 12–20). The average preoperative Cobb angle was 56° (range, 47°–85°). The average number of levels fused was 11 (range, 9–13). SCR could be accomplished intraoperatively, only consuming approximately 20 ​min. The enriching multiples of measured cellular elements were approximately 2.3–4.2. At final follow-up, the average Cobb angle correction was 83% (range, 61–96%). There was no obvious loss in correction with an average loss of 1.1° (2%). The visual analogue scale score and the Oswestry Disability Index score at final follow-up were significantly ameliorated than those preoperatively. The Scoliosis Research Society 30 questionnaire revealed remarkable improvement in the domains “pain”, “self-image/appearance”, and “satisfaction with management”. There was neither pseudarthrosis nor severe complication.ConclusionThe use of SCR technology could be considered as an effective method for promoting spinal fusion in treating AIS. We proposed a safe, simple, and rapid approach to obtain effective bone grafts for spinal fusion.The translational potential of this articleEnriched bone marrow obtained by selective cell retention technology has the potential to promote spinal fusion for the treatment of adolescent idiopathic scoliosis.

Minimally invasive lateral transpsoas approach for lumbar corpectomy and stabilization

Background:Here, we present our experience with the minimally invasive (MI) transpsoas approach for lumbar corpectomy and stabilization. Transpsoas approach accesses the lumbar spine and includes both the direct lateral interbody fusion and extreme lateral interbody fusion techniques. Both procedures utilize a tubular retractor system which facilitates adequate retraction and direct visualization of the target, while supposedly reducing soft tissue trauma.Case Description:We evaluated two patients, one with a traumatic L2 wedge compression fracture and the other with an L3 pathological compression fracture due to multiple myeloma. Both patients underwent MI transpsoas lumbar corpectomy, anterior column reconstruction with an expandable cage, and posterior pedicle screw instrumentation to correct a kyphotic deformity. Both patients were mobilized on the 1st postoperative day and experienced significant postoperative pain relief.Conclusion:In two cases involving L2 and L3 compression fractures, MI transpsoas lumbar corpectomy was safely performed, with reduced perioperative and postoperative morbidity. Here, the transpsoas approach also allowed for early mobilization, adequate postoperative biomechanical stability, and resulted in immediate good outcomes.

Risk factors of instrumentation failure and pseudarthrosis after stand-alone L5-S1 anterior lumbar interbody fusion: a retrospective cohort study.

L5-S1 stand-alone anterior lumbar interbody fusion (ALIF) is a reliable technique to treat symptomatic degenerative disc disease but remains controversial for treatment of isthmic spondylolisthesis. In the present study the authors aimed to identify risk factors of instrumentation failure and pseudarthrosis after stand-alone L5-S1 ALIF and to evaluate whether instrumentation failure influenced the rate of fusion. The study included 64 patients (22 [34.4%] male and 42 [65.6%] female, mean age 46.4 years [range 21-65 years]) undergoing stand-alone L5-S1 ALIF using radiolucent anterior cages with Vertebridge plating fixation in each vertebral endplate. Clinical and radiographic data were reviewed, including age, sex, pelvic parameters, segmental sagittal angle (SSA), C7/sacro-femoral distance (SFD) ratio, C7 sagittal tilt, lumbar lordosis (LL), segmental LL, percentage of L5 slippage, L5-S1 disc angle, and posterior disc height ratio. Univariate and multivariate analyses were used to identify risk factors of instrumentation failure and pseudarthrosis. At a mean follow-up of 15.9 months (range 6.6-27.4 months), fusion had occurred in 57 patients (89.1%). Instrumentation failure was found in 12 patients (18.8%) and pseudarthrosis in 7 patients (10.9%). The following parameters influenced the occurrence of instrumentation failure: presence of isthmic spondylolisthesis (p < 0.001), spondylolisthesis grade (p < 0.001), use of an iliac crest bone autograft (p = 0.04), cage height (p = 0.03), pelvic incidence (PI) (p < 0.001), sacral slope (SS) (p < 0.001), SSA (p = 0.003), and LL (p < 0.001). Instrumentation failure was statistically linked to the occurrence of L5-S1 pseudarthrosis (p < 0.001). On multivariate analysis, no risk factors were found. L5-S1 isthmic spondylolisthesis and high PI seem to be risk factors for instrumentation failure in case of stand-alone L5-S1 ALIF, findings that support the necessity of adding percutaneous posterior pedicle screw instrumentation in these cases.

Outcomes of Minimally Invasive Oblique Lumbar Interbody Fusion in Patients with Lumbar Degenerative Disease with Rheumatoid Arthritis.

Standard treatment protocols for lumbar degenerative lesions in the setting of rheumatoid arthritis (RA) are lacking. The purpose of this study was to evaluate the clinical and radiologic outcomes of minimally invasive oblique lumbar interbody fusion (MI-OLIF) in RA patients having degenerative lumbar spine lesions. This was a retrospective hospital-based case series (evidence level 4). Eight patients with degenerative lumbar disease with significant back pain and neurologic claudication underwent MI-OLIFwith polyetheretherketone cage insertion and posterior pedicle screw instrumentation. The clinical outcomes were measured by the numerical rating scale (NRS) for back and leg pain and the Oswestry Disability Index (ODI), and radiologic outcomes were studied on radiographs, computed tomography, and magnetic resonance imaging. Minimum follow-up duration was 1 year. Mean NRS results for back and leg pain preoperatively were 6.3 and 7.1 that improved to 2.6 and 2 for back and leg pain, respectively, at last follow-up. The mean ODI scores preoperatively were 58.02 that improved to 39.06 at last follow-up. All patients had good functional outcomes, good fusion rates, and were able to continue their activities of daily living without much disability at last follow-up. MI-OLIF in patients with symptomatic lumbar spine degenerative lesions with RA seems to provide good short-term clinical and radiologic outcomes.

Transforaminal Interbody Debridement and Fusion to Manage Postdiscectomy Discitis in Lumbar Spine

Traditionally, nonoperative management with long-term antibiotics and bed rest has been recommended as first-line treatment for most patients with postoperative discitis. A recent trend in treatment under a limited range of indications has been to perform surgical débridement followed by long-term administration of antibiotics. This descriptive study investigated whether transforaminal lumbar interbody débridement and fusion (TLIDF) combined with intravenous antibiotics is appropriate to manage postdiscectomy discitis. This study retrospectively analyzed demographic data, laboratory data, and radiography and magnetic resonance imaging of 10 patients with postoperative discitis who underwent surgical TLIDF followed by antibiotic treatment. Preoperative and postoperative spine sagittal alignment, visual analog scale scores, and Kirkaldy-Willis criteria for functional outcomes were evaluated. An infection clearance rate of 100% was ultimately achieved for the patients who underwent TLIDF with short posterior instrumentation. TLIDF yielded better outcomes than traditional conservative treatment in terms of spine alignment correction, functional outcomes, and quality of life. Based on previously reported data and the findings of this study, we suggest that surgical intervention should be used in certain cases, as it can achieve better outcomes than conservative treatment. We recommend a novel single posterior approach with TLIDF and posterior pedicle screw instrumentation for management of postdiscectomy discitis.

Clinical outcomes of posterior pedicle screw instrumentation without osteotomy in the management of adolescent idiopathic scoliosis.

The aim of the study was to identify the effectiveness of posterior pedicle screw instrumentation without osteotomy in the management of adolescent idiopathic scoliosis (AIS).The AIS patients underwent standing anteroposterior and lateral radiography before and after surgery. Age, sex, Lenke type, preoperative and postoperative Cobb angle, and all the related complications were recorded at final follow-up.We investigated data from 137 AIS patients who underwent posterior pedicle screw instrumentation without osteotomy from January 2012 to January 2016 with >2 years follow-up. Mean age was 14.3 ± 1.5 years at operation. The preoperative and latest postoperative coronal Cobb angle was 60 ± 12° and 9 ± 5°, respectively. Additionally, complications were noted in 6 patients. However, the prognosis of all the AIS patients was good, and the satisfaction of the Scoliosis Research Society Outcomes Instrument (SRS-22) questionnaire was 4.4 ± 0.5 at final follow-up.In the management of mild and moderate AIS, satisfactory clinical results can be obtained using posterior pedicle screw instrumentation without osteotomy.

Dual Sequential Short Anterior Correction in Double Major Adolescent Idiopathic Scoliosis

Study Designretrospective comparative study. IntroductionThe standard surgical technique for double major adolescent idiopathic scoliosis (AIS) has been the fusion of both thoracic and thoracolumbar/lumbar curves from the posterior approach. Although short anterior correction is established in AIS with single thoracic or thoracolumbar/lumbar curves, anterior correction in double major curves has not yet been described. The purpose of this study is to compare this novel technique with standard posterior pedicle screw instrumentation in double major AIS. Methods19 consecutive patients with a double major AIS were treated surgically either with pedicle screw instrumentation and posterior fusion (n = 11) or dual anterior short instrumentation and fusion (n = 8) of both curves. The mean follow-up was 5.6 ± 3 years (2–10 years). Clinical and radiologic results, results of pulmonary function, and Scoliosis Research Society (SRS) questionnaire are analyzed and compared. ResultsThe length of fusion was 7.6 ± 0.7 vertebrae with the anterior technique and 12 ± 1 vertebrae with the posterior technique (p < .001). Cobb angle correction was 78% and 53% in thoracic curves, and 80% and 59% in lumbar curves with posterior and anterior technique respectively (p < .05). The preoperative pulmonary function remained unchanged to the last follow-up in both groups. The scores of SRS-24 questionnaire were similar preoperatively and at the last follow-up in both groups. ConclusionThis novel technique of dual sequential short anterior correction is an alternative to the standard posterior long fusions in the double major AIS. A significantly less amount of mobile segments needs to be fused leaving the thoracolumbar junction mobile and saving at least one lumbar mobile segment distally. Level of EvidenceLevel III.

232 - Is the Use of Multimodal Anesthesia for Postoperative Pain Control Effective in Patients Undergoing One– or Two-Level Anterior Lumbar Interbody Fusions with Posterior Percutaneous Pedicle Screw Instrumentation?

232 - Is the Use of Multimodal Anesthesia for Postoperative Pain Control Effective in Patients Undergoing One– or Two-Level Anterior Lumbar Interbody Fusions with Posterior Percutaneous Pedicle Screw Instrumentation?

Chyluria and chylothorax after posterior selective fusion for adolescent idiopathic scoliosis.

To describe and discuss the diagnostic and treatment complexity of lymphatic system complications after scoliosis surgery. Surgery for adolescent idiopathic scoliosis is very commonly performed with posterior pedicle screw instrumentation. Complications of the anteriorly based lymphatic system are, therefore, rare. We present a case with complications related to the lymphatic system, which have not been reported before after this type of surgery. After standard Th3 to Th12 posterior spinal reduction and fusion of a moderate thoracic curve, chyluria and a chylothorax developed in an adolescent girl. This appeared to be caused by an obstruction of the thoracic duct. Thorax drainage and finally thoracoscopic intervention prevented further pulmonal impairment. The exact cause could not be identified and the persistent lymph drainage problems had to be treated with a medium chain triglyceride diet. With this report, we aim to create awareness of the lymphatic system in general and the possibility of severe complications, even after a posterior only approach of the vertebral column.

Retrospective study on the CT evaluation of accuracy of pedicle screw placement in posterior lumbosacral instrumentation

Objectives To evaluate the accuracy of posterior pedicle screw placement in a multicentric retrospective clinical study and analyze the potential reasons of pedicle breaches. Methods From January 2014 to December 2014, 293 patients with conventional posterior pedicle screw instrumentation up to inclusion and exclusion criteria were recruited from 3 different hospitals. The operative levels included L4 in 219 cases, L5 in 270 cases and S1 in 95 cases. The screw positions in the pedicles were verified by 2 professional observers independently under computed tomography reconstruction within 24 hours to 48 hours postoperatively. The locations and grades of breached pedicles were recorded in each segment and related factors were analyzed. Pedicle breach rates in 3 hospitals were stratified and analyzed as well. All patients were followed up and neurological deficits as well as other postoperative complications were registered. Results There were 280 pedicle breaches in a total of 1166 instrumented pedicles of 293 patients. The breach rates in different levels were listed as 29.0% (126/436) in L4, 24.5% (132/539) in L5 and 11.5% (22/191) in S1. There were no significant differences in pedicle breach rates between L4 and L5, while the breach rates in L4 and L5 were both significantly higher than those in S1. For severe violation from L4 to S1, 6.3% (8/126), 14.4% (19/132) and 36.4% (8/22) were confirmed respectively. The incidences of high risk pedicle breach (grade III, grade IV) of L5 and S1 were significantly higher than those of L4. Furthermore, the inferomedial breach rates quantified from L4 to S1 were 58.7% (74/126), 75% (99/132), 86.4% (19/22) respectively. The breach rates in the inferomedial wall of the L5, S1 pedicles were statistically higher than those of L4. Pedicle breach rates among 3 hospitals varied while the characteristics of the locations, the grades and the segments of breached pedicles were similar to overall results in each hospital. There were 9 cases of cerebrospinal fluid leakage and 2 cases of transient nerve root injuries. Conclusion There are no significant differences in pedicle breach rates between L4 and L5. However, pedicle breach rates in L4 and L5 are statistically higher than those in S1. The incidence of high risk pedicle breach and inferomedial wall breach of L5 and S1 are significantly higher than that of L4. In addition, the incidences of pedicle breaches and related complications occurred more in lower-level hospitals. Key words: 【Key word】Lumbar vertebrae; Sacrum; Spinal fusion; Bone Screws