Post-operative shift in pain profile following fusion surgery for adult spinal deformity: a cluster analysis.

PURPOSE: Adult spinal deformity (ASD) is associated with a combination of back and leg pain of various intensities. The objective of the present study was to investigate the diverse reaction of pain profiles following ASD surgery as well as post-operative patient satisfaction. METHODS: Multicenter surveillance collected data for patients ≥ 19 years old who underwent primary thoracolumbar fusion surgery at > 5 spinal levels for ASD. Two-step cluster analysis was performed utilizing pre-operative numeric rating scale (NRS) for back and leg pain. Radiologic parameters and patient-reported outcome (PRO) scores were also obtained. One-year post-operative outcomes and satisfaction rates were compared among clusters, and influencing factors were analyzed. RESULTS: Based on cluster analysis, 191 ASD patients were categorized into three groups: ClusterNP, mild pain only (n = 55); ClusterBP, back pain only (n = 68); and ClusterBLP, significant back and leg pain (n = 68). ClusterBLP (mean NRSback 7.6, mean NRSleg 6.9) was the oldest 73.4 years (p < 0.001) and underwent interbody fusion (88%, p < 0.001) and sacral/pelvic fixation (69%, p = 0.001) more commonly than the other groups, for the worst pelvis incidence-lumbar lordosis mismatch (mean 43.7°, p = 0.03) and the greatest sagittal vertical axis (mean 123 mm, p = 0.002). While NRSback, NRSleg and PRO scores were all improved postoperatively in ClustersBP and BLP, ClusterBLP showed the lowest satisfaction rate (80% vs. 80% vs. 63%, p = 0.11), which correlated with post-operative NRSback (rho = -0.357). CONCLUSIONS: Cluster analysis revealed three clusters of ASD patients, and the cluster with the worst pain back and leg pain had the most advanced disease and showed the lowest satisfaction rate, affected by postoperative back pain.

Calculation of the minimal clinically important difference in operated patients with adult spine deformity: advantages of the ROC method and significance of prevalence in threshold selection.

PURPOSE: The Minimal Clinically Important Difference (MCID) is crucial to evaluate management outcomes, but different thresholds have been obtained in different works. Part of this variability is due to measurement error and influence of the database, both essential for calculating the MCID. The aim of this study was to introduce the association of the ROC method in the anchor-based MCID calculation for ODI, SRS-22r, and SF-36, to objectively set the threshold for the anchor-based MCID in an adult spine deformity (ASD) population. METHODS: Multicentric study based on a prospective database of consecutively operated ASD patients. An anchor question was used to assess patients' quality of life after surgery. Different approaches were used to calculate the MCID and then compared: SEM (Standard Error of Measurement), MDC (Minimal Detectable Change), and anchor-based MCID with ROC method. RESULTS: 516 patients were included. Those who responded with 6 and 7 to the anchor question were considered improved. The MCID ranges obtained with the ROC method exhibited the lowest variability. Prediction error rates ranged from 31% (SRS-22r) to 41% (SF-36 MCS). The MCID ranges spanned between 12 and 15 for ODI, 0.6 and 0.73 for SRS-22r, 6.62 and 7.41 for SF-36 PCS, and between 2.69 and 5.63 for SF-36 MCS. CONCLUSION: The ROC method proposes an MCID range with error rate, and can objectively determine the threshold for distinguishing improved and non-improved patients. As the MCID correlates with the utilized database and error of measurement, each study should compute its own MCID for each PROM to allow comparison among different publications. LEVEL OF EVIDENCE: II.

Long spine fusions to the sacrum-pelvis are associated with greater post-operative proximal junctional kyphosis angle in sitting position.

STUDY DESIGN: A single-centre retrospective study. BACKGROUND AND PURPOSE: Although adult patients spend most of their time in sitting positions, the assessment of spinopelvic parameters in adult deformity surgery is commonly performed in standing X-rays. Our study compares the standing and sitting sagittal alignment parameters in subjects who underwent thoracolumbar fusion. METHODS: Patients who underwent corrective surgery for adult scoliosis with at least five instrumented vertebra were stratified according to the upper instrumented vertebra (UIV) and pelvic fixation. Group A:UIV proximal to T6 with pelvis fixation. B:UIV lower than T6 and pelvic fixation. Group C: thoracolumbar fusion without pelvic fixation. Post-operative spinopelvic sagittal parameters were measured in both standing and sitting X-rays. RESULTS: A total of 51 patients were enrolled in the study (11:Males and 40:Females). The mean age was 52.3 ± 21.7y/o. The comparison of post-operative standing and sitting X-ray within the group A and B showed that a significant change was observed in terms of JA-Junctional Angle-(Group A 6.3 ± 4.3 vs. 8.1 ± 3.3, p value = 0.03) (Group B 8.5 ± 6.4 vs. 10.9 ± 6.4, p value = 0.02). Group C showed statistically significant difference in terms of PT (15.6 ± 11.2 vs. 19.3 ± 9.2, p value = 0.04), AVA-Acetabular Version Angle-(41.1 ± 5.9 vs. 48.3 ± 6.6, p value < 0.01) and LL (- 51.3 ± 16.0 vs. - 42.6 ± 10.7, p value < 0.01). CONCLUSION: In our series, the post-operative sagittal alignment showed peculiar behaviours and adaptations in sitting position, depending on the length and the site of the instrumented area. If the pelvis is included, the JA tends to significantly increase in sitting position. These findings can improve the knowledge of pathologies as proximal junctional kyphosis or specific cases of anterior hip impingement. LEVEL OF EVIDENCE: IV.

Post-operative L5 radiculopathy after L5-S1 hyperlordotic anterior lumbar interbody fusion (HL-ALIF) is related to a greater increase of lordosis and smaller post-operative posterior disc height: results from a cohort study.

STUDY DESIGN: A single-centre retrospective study. BACKGROUND AND PURPOSE: This study aims to investigate the rate of L5 radiculopathy, to identify imaging features associated with the complication and to evaluate the clinical outcomes in adult spine deformity patients undergoing L5-S1 ALIF with hyperlordotic cages. METHODS: Design: retrospective cohort study. A single-centre prospective database was queried to analyse patients undergoing hyperlordotic (HL) ALIF with posterior fusion to correct spinal deformity. Clinical status was evaluated by back and leg pain numeric rate scale and Oswestry Disability Index pre-operatively and at 3-, 6- and 12-month follow-up. Spinopelvic parameters, such as pelvic incidence, pelvic tilt, lumbar lordosis and L5-S1 lordosis, posterior disc height (PDH) and anterior disc height, were assessed pre-operatively and post-operatively on standardized full-spine standing EOS images. The sagittal foraminal area was measured pre- and post-operatively on a CT scan. RESULTS: Thirty-nine patients with a mean age of 63.2 ± 8.6 years underwent HL-ALIF from January 2016 to December 2019. Seven of them developed post-operative root pain (5) or weakness (2) (Group A), while thirty-two did not (Group B). Root impairment was associated with greater segmental correction magnitude, 26° ± 11.1 in Group A versus 15.1° ± 9.9 in Group B (p < 0.05), and to smaller post-operative PDH, 5.9 mm ± 2.7 in Group A versus 8.3 mm ± 2.6 (p < 0.05). CONCLUSIONS: Post-operative root problems were observed in 17.9% of patients undergoing HL-ALIF for adult spine deformity. L5 radiculopathy was associated with larger sagittal angular corrections and smaller post-operative posterior disc height. One patient (2.6%) needed L5 root decompression. At 12 months of follow-up, results were equivalent between groups. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Anterior Lumbar Interbody Fusion (ALIF) L5-S1 with overpowering of posterior lumbosacral instrumentation and fusion mass: a reliable solution in revision spine surgery.

BACKGROUND AND PURPOSE: In cases of spine surgical revisions of patients affected by sagittal malalignment, the restoration of the ideal lumbar lordosis (LL) is mandatory. ALIF procedures represent a powerful and effective approach to improve the LL in case of hypolordosis. This study evaluates the feasibility of ALIF to overpower posterior lumbar instrumentation and fusion mass in revision spine surgery and secondarily to estimate complications, clinical and radiological outcomes. METHODS: This is a single-center retrospective analysis of prospectively collected data on the use of ALIF overpowering in cases of lumbosacral instrumentation and/or fusion. Demographic, comorbidity, corrective strategy adopted, surgical data, clinical and radiological results, and intraoperative and postoperative complications were recorded. RESULTS: Twelve patients (3 male; 9 female) underwent overpowering ALIF L5-S1 were included in the study with a mean FU of 34.0 ± 13.4 months. In 10 cases, a posterior titanium instrumentation and fusion mass were present; in 2 patients, only a fusion mass was present. Indicators of pain and disability improved in all patients (p < 0.01). Sagittal realignment with the restoration of ideal spinopelvic parameters was obtained in all cases. One peritoneal lesion requiring intraoperative suture without sequelae, two cases of postoperative radiculopathy, and one posterior wound infection requiring surgical debridement and antibiotic therapy were reported. CONCLUSIONS: Anterior implant of lordotic and hyperlordotic cages with increasing segmental lordosis is possible in the presence of posterior instrumentation and/or solid fusion mass. The biomechanical strength of this corrective technique can overcome posterior instrumentation and bone fusion resistance, therefore allowing a single-staged surgery for sagittal realignment.

Impact of pedicle subtraction osteotomy on health-related quality of life (HRQOL) measures in patients undergoing surgery for adult spinal deformity: a systematic review and meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. BACKGROUND: Three-column osteotomies (3-CO) have gained popularity in the last decade as part of the armamentarium for the surgical correction of sagittal imbalance in patients with adult spinal deformity (ASD). Three-column osteotomies in the form of pedicle subtraction osteotomy (PSO) may be necessary to achieve adequate correction for severe and rigid spinal deformity. Studies reporting improvement in health-related quality of life (HRQOL) with validated outcome measures after PSO surgery are sparse and currently consist of small series. OBJECTIVE: Evaluate the improvement in HRQOL measures following PSO for adult spinal deformity. METHODS: Two independent reviewers conducted a systematic review of the English literature between period 1996 and 2019 for articles reporting outcome of PSO in patients with ASD according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Inclusion criteria were studies consisting of patient-reported outcome Oswestry Disability Index (ODI) and Scoliosis Research Society 22 or 24 (SRS) outcomes after PSO surgery for adult spine deformity patients (18 years or older) with a minimum follow-up of 1 year. RESULTS: Eight studies with 431 PSOs were included in the meta-analysis. The results showed a statistically significant improvement in ODI in PSO (P < 0.0001), and the mean clinically important difference was achieved with both ODI (50.46 (45.5-55.4) preoperatively to 32.78 (29.7-39) postoperatively) and SRS (2.49 (2.38-2.7) preoperatively to 3.26 (2.8-4.1) postoperatively) scores. CONCLUSION: This meta-analysis did find improvements in the health-related quality of life in patients undergoing PSO surgery for adult spinal deformity.

Changes in pelvic anatomy after long corrective fusion using iliac screws for adult spinal deformity.

PURPOSE: Long fusion to the sacrum with iliac screws can decrease pelvic incidence (PI). Considering the physiological range of movement of the sacroiliac joint, this decrease may be relatively extreme. The purpose of the study was to determine changes in pelvic morphology after orthopedic surgery using long fusion with iliac screws, and examine the relationship between changes in PI and morphology. METHODS: We included data from 80 consecutive patients who underwent corrective surgery for adult spine deformity (72 female and 8 male; mean age: 71.1 years). We examined preoperative and early postoperative full-standing X-ray images and pelvic computed tomography of the patients and compared the following: (1) pre- and postoperative pelvic measurements including PI, (2) correlations between change of PI, iliac angle, and distance between posterior superior iliac spines (DPSIS). RESULTS: After surgery, PI decreased significantly (- 3.3°, 95% confidence interval [95%CI] - 4.3° to - 2.3°, P < 0.01) and DPSIS increased significantly (+ 2.7 mm, 95%CI 1.7 to 3.8 mm, P < 0.01). By contrast, iliac angle decreased significantly (- 1.4°, 95%CI - 2.1° to - 0.7°, P < 0.01). There were significant correlations between changes of PI and iliac angle (r = 0.34, P < 0.01) and between changes of DPSIS and iliac angle (r = - 0.44, P < 0.01). CONCLUSIONS: We observed changes in pelvic morphology associated with spinal pelvic correction surgery using iliac screws and changes in pelvic incidence related to these changes in pelvic morphology. We recommend selecting pelvic anchors and surgical procedures considering potential movement of the sacroiliac joint. These slides can be retrieved under Electronic Supplementary Material.

Focal disorders of the spine with compensatory deformities: how to define them.

PURPOSE: In this paper, the authors propose classifying the epiphenomenon of spinal deformity in two different categories: structural deformity, when the main driver of the observed deformity is a fixed and stiff alteration of the spinal segments, and compensatory deformity, which includes cases where the observed deformity is due to focal abnormalities. This last category comprises, but is not limited to, spinal stenosis, spondylolisthesis, disc herniation, infection or tumor, hip disease or neurological disease (such as Parkinson's disease). METHOD: Narrative review article. RESULTS: We analyzed the focal diseases of the spine that may cause a compensatory deformity inducing adaptation in the unaffected part of the spine. CONCLUSION: The compensatory mechanisms involved in adaptive deformity represent an attempt to maintain a global alignment, to escape from pain or to control body posture. These slides can be retrieved under Electronic Supplementary material.

Hypercomplex pedicle subtraction osteotomies: definition, early clinical and radiological results and complications.

PURPOSE: To describe hypercomplex pedicle subtraction osteotomies (HyC-PSO) for adult spine deformity with sagittal imbalance in terms of preoperative, intraoperative and postoperative outcomes and complications. METHODS: From a prospective single centre database, patients undergoing PSO between January 2016 and May 2017 were reviewed. HyC-PSO were defined as those in patients with one of the following conditions: sagittal correction > 45° needed at a single level or at 1-3 consecutive vertebrae, more than 60° of total sagittal correction needed and PSO on segments of the spine with congenital deformities. RESULTS: 22 patients were included, 14 had standard PSO (group A) and 8 had HyC-PSO (group B). Significant correction of lumbar lordosis (LL) and pelvic (PT) was noted in both groups (p < 0.01). Operative time was longer in HyC-PSO, 604 min compared to standard PSO, 478 min. A trend versus greater intraoperative blood loss (3837 vs 2285 ml) and greater intraoperative blood infusion (from cell saver plus homologous, 2306 vs 1280 ml) was recorded in HyC-PSO (ns). Patients in group B received significantly more blood units intra and postoperatively (8.25 vs 4.71 units, p = 0.006). Sagittal correction at the PSO level (54.7°-30° to 85°-vs 26.8°-8° to 39°-, p = 0.000) and total sagittal correction (64.5°-50 to 95°-vs 39.8°-20° to 51°-, p = 0.000) were greater in HyC-PSO. PROMs at the last available follow-up did not show significant differences between groups for any of the outcomes analyzed. Complications were similar in both groups. CONCLUSION: This is the first report on hypercomplex pedicle subtraction osteotomies. Hypercomplex PSO describes a subset of clinical scenarios with increased surgical effort that can be measured as longer surgical time and greater blood transfusion requirements. Successful correction of misalignment can be achieved in this specific group of patients, and clinical results and complications profile could be similar to standard PSO procedures.

Complications in adult spine deformity surgery: a systematic review of the recent literature with reporting of aggregated incidences.

PURPOSE: To review the incidence of perioperative and late complications of surgery for spinal deformity (ASD). METHODS: Review of the literature. We reviewed recent literature in English to investigate the incidence of complications in ASD surgery in the perioperative (≤ 3 months post-operative) and late (> 3 months post-operative) periods. Randomized-controlled trials, non-randomized trials, cohort studies, case-control studies, and case series published in 2005 or later were included. We divided articles according to surgical technique: open procedures (OP), minimally invasive surgery (MIS), and hybrid procedures (HP). Complications were recorded, grouped by surgical technique, and then classified according to a proposed Grading of Incidence of Complications (IOC). RESULTS: Ninety-six publications reporting on 12,168 patients were included; 68 were level IV of evidence studies, 24 were level III, and 4 level II. Perioperative IOC was 26.5% in OP, 36.4% in HP, and 24.2% in MIS. Late IOC was 11.1% in OP, 15.4% in HP, and 14.0% in MIS. IOC was significantly higher for hybrid procedures compared to both open and MIS procedures. CONCLUSIONS: Reported complications of surgery for ASD in the recent literature are frequent (24-36% perioperative plus 11-15% late). Open procedures were the most extensively reported in the literature. Complication rates are similar for OP and MIS. HP presented higher IOC likely due to the combination of OP and MIS respective complications. Small number of studies and heterogeneity in reporting could result in risk of bias in these results. Large-scale registry-based studies can fill this gap in the future. These slides can be retrieved under Electronic Supplementary Material.

Long fusions to S1 with or without pelvic fixation can induce relevant acute variations in pelvic incidence: a retrospective cohort study of adult spine deformity surgery.

PURPOSE: The purpose of this study is to verify if any changes occur in pelvic incidence (PI) in adult patients undergoing long fusion to sacrum for spine deformity and to describe the effect of fixation to pelvis on these variations. METHODS: We conducted a cross sectional study. Sixty-six adults patients, 87% females (mean ± SD age: 65.1 ± 7.6 years), undergoing fusion from the thoracic spine to the sacrum for adult spine deformity were included. Patients were divided in two different groups: Group A: sacral fixation alone and Group B: sacral fixation plus pelvis fixation. Pre and postoperative standardized full-standing X-rays were analyzed with measurement of: PI, pelvic tilt (PT), lumbar lordosis (LL) and sagittal vertical axis (SVA). RESULTS: A significant effect of time interaction (preoperative to early postoperative; F = 59.93, F = 44.78 and F = 39.87, all p < 0.001) existed for PT, SS and TK in both groups (all, p < 0.001). After adjustment for patients' age (>65 vs. <65 years), a statistically significant increase of PI was observed in patients >65 years (p = 0.006) in Group A between preoperative and postoperative measurements. All patients in Group B exhibited a decrease in PI from preoperative to postoperative. CONCLUSIONS: Older patients undergoing long fusion to the sacrum without pelvic fixation had an increase in PI after surgery. Conversely, pelvic fixation with hips intraoperatively extended has decreased the value of PI from pre- to early postoperative. These changes could be related to degeneration of the sacroiliac joints causing increased rotational mobility and the magnitude of the differences is in the range of clinical relevance.

Contemporary utilization of three-column osteotomy techniques in a prospective complex spinal deformity multicenter database: implications on full-body alignment and perioperative course.

BACKGROUND: Research has focused on the increased correction from a three-column osteotomy (3CO) during adult spinal deformity (ASD) surgery. However, an in-depth analysis on the performance of a 3CO in a cohort of complex spinal deformity cases has not been described. STUDY DESIGN/SETTING: This is a retrospective study on a prospectively enrolled, complex ASD database. PURPOSE: This study aimed to determine if three-column osteotomies demonstrate superior benefit in correction of complex sagittal deformity at the cost of increased perioperative complications. METHODS: Surgical complex adult spinal deformity patients were included and grouped into thoracolumbar 3COs compared to those who did not have a 3CO (No 3CO) (remaining cohort). Rigid deformity was defined as ΔLL less than 33% from standing to supine. Severe deformity was defined as global (SVA > 70 mm) or C7-PL > 70 mm, or lumbopelvic (PI-LL > 30°). Means comparison tests assessed correction by 3CO grade/location. Multivariate analysis controlling for baseline deformity evaluated outcomes up to six weeks compared to No 3CO. RESULTS: 648 patients were included (Mean age 61 ± 14.6 years, BMI 27.55 ± 5.8 kg/m2, levels fused: 12.6 ± 3.8). 126 underwent 3CO, a 20% higher usage than historical cohorts. 3COs were older, frail, and more likely to undergo revision (OR 5.2, 95% CI [2.6-10.6]; p < .001). 3COs were more likely to present with both severe global/lumbopelvic deformity (OR 4), 62.4% being rigid. 3COs had greater use of secondary rods (OR 4st) and incurred 4 times greater risk for: massive blood loss (> 3500 mL), longer LOS, SICU admission, perioperative wound and spine-related complications, and neurologic complications when performed below L3. 3COs had similar HRQL benefit, but higher perioperative opioid use. Mean segmental correction increased by grade (G3-21; G4-24; G5-27) and was 4 × greater than low-grade osteotomies, especially below L3 (OR 12). 3COs achieved 2 × greater spinopelvic correction. Higher grades properly distributed lordosis 50% of the time except L5. Pelvic compensation and non-response were relieved more often with increasing grade, with greater correction in all lower extremity parameters (p < .01). Due to the increased rate of complications, 3COs trended toward higher perioperative cost ($42,806 vs. $40,046, p = .086). CONCLUSION: Three-column osteotomy usage in contemporary complex spinal deformities is generally limited to more disabled individuals undergoing the most severe sagittal and coronal realignment procedures. While there is an increased perioperative cost and prolongation of length of stay with usage, these techniques represent the most powerful realignment techniques available with a dramatic impact on normalization at operative levels and reciprocal changes.

The Advantages of 4-rod Construct over the 2-rod Techniques in Adult Spinal Deformity Patients who Underwent Pedicle Subtraction Osteotomy: A Multicenter Retrospective Comparative Study.

OBJECTIVE: In this retrospective study we compared clinicoradiologic outcomes and complication profiles of the traditional 2-rod construct versus the 4-rod construct in patients with adult spinal deformity (ASD) who underwent pedicle subtraction osteotomy (PSO). METHODS: We performed a retrospective review of 208 ASD patients at 2 referral centers who underwent lumbar PSO and long fusion from thoracic to the pelvis. Two different techniques, including the 4-rod construct and the traditional 2-rod technique, were used at the PSO level. Clinicoradiologic outcomes and complication profiles of the patients were documented and compared statistically between the groups. RESULTS: The 4-rod construct was associated with statistically lower rates of rod fracture (44.8% vs. 26.4%, P < 0.01), pedicular screw loosening at the PSO level (25.3% vs. 14.0%, P = 0.04), and reoperation (49.4% vs. 33.9%, P = 0.02). Radiologically, the 4-rod construct was associated with higher degree of lumbar lordosis (LL) (-37.4°vs. -26.8°; P < 0.01) and improved pelvic tilt (PT) (-17.2° vs. -9.9°; P < 0.01) and sacral vertical axis (SVA) corrections (-211.5° vs. -192.2°; P = 0.04). Overall, the 4-rod construct was associated with improved quality of life (P = 0.04) and statistically lower Oswestry Disability Index score at 12 months postoperatively (P < 0.01). CONCLUSIONS: Our results showed that the 4-rod construct was associated with statistically lower rates of rod fracture and pedicular screw loosening at the osteotomy level, higher degree of LL correction and improved PT and SVA than the 2-rod technique. The 4-rod construct was also associated with improved quality of life and Oswestry Disability Index and lower complication profiles.

Defining the Post-Operative Progression of Degenerative Scoliosis: An Analysis of Cases without Instrument Failure.

OBJECTIVE: The expected post-operative changes in radiographic alignment over time remain poorly defined in patients surgically treated for degenerative scoliosis without instrument failure. Here we aim to describe the optimal natural progression of radiographic degenerative scoliosis at multiple timepoints in patients treated with a transforaminal lumbar interbody fusion (TLIF). METHODS: We identified an initial retrospective cohort of 114 patients treated with a TLIF for degenerative scoliosis between 2018 and 2022, with 39 patients ultimately meeting the imaging inclusion criteria. Patients who completed a primary or revision procedure with no evidence of instrument failure, proximal junctional kyphosis, or proximal junctional failure at last follow-up were included. Radiographic measurements of spinopelvic alignment were manually extracted from X-Ray scoliosis films. RESULTS: Thirty-nine patients (mean age 62.6 ± 8.7, mean follow-up 2.9 years), of which 23 underwent a primary TLIF (Primary) and 16 a revision procedure (Revision), were analyzed. Patients in the Primary group experienced a durable improvement in Thoracolumbar Cobb angle (-25° ± 15°), Thoracic Kyphosis (10° ± 13°), and Pelvic Incidence/lumbar lordosis mismatch (PI/LL) (-19° ± 19°) through the first year of follow-up. In the Revision group, at one year follow-up, all measures of spinopelvic alignment except PI/LL mismatch had reverted to pre-operative levels. Thoracolumbar Cobb angle decreased to a significantly greater degree in the Primary group compared to the Revision group. CONCLUSION: Primary TLIF operations without instrument failure consistently improve radiographic outcomes in three key measures through the first year. For revision procedures, there appears to be modest radiographic benefit at follow-up.

The Effect of Anaemia on Intra-operative Neuromonitoring Following Correction of Large Scoliosis Curves: Two Case Reports.

The correction of anemia is important in reversing significant intraoperative bilateral motor-evoked potential (MEP) loss following rod placement for correction of large scoliosis curves. This article presents a retrospective review of intraoperative neuromonitoring (IONM) data, anesthesia records, and medical charts of two patients with significant bilateral MEP changes associated with posterior spinal surgery for deformity correction. A 70 kg 12-year-old and a 44 kg 16-year-old female with main thoracic curves underwent a posterior scoliosis correction with multilevel posterior column osteotomies. Following rod insertion, significant reduction in the bilateral lower extremity MEP occurred in both cases despite mean arterial pressure exceeding 70 mmHg, which was presumed to be due to the scale of the correction attempted in the setting of haemorrhage which rendered the patient acutely anaemic, thus compromising cord vasculature and oxygen delivery. The rods were removed and packed red blood cell transfusions were administered in response to acute anaemia as a result of haemorrhage in both cases. Neither was noted to be anaemic preoperatively. Once the MEP signals improved, the rods were reinserted and correction was attempted, limited by neuromonitoring signals and resistance of the bony anchors to pullout. At closure, the MEPs were near baseline in the first case and >50% of baseline in the second. There were no changes in the somatosensory evoked potential signals in either case. Post-operative neurological function was normal in both patients. Correcting the circulating haemoglobin concentration through blood product resuscitation allowed for safe correction of spinal deformity in two cases with significant bilateral MEP loss following the initial placement of rods.

Does Pedicle Morphology Affect the Safety and Accuracy of Pedicle Screw Placement Using 3D-Printed Guides? A 5-Year, Single-Center Experience With 2210 Screws Placed for Adult Spinal Deformity Reconstruction.

BACKGROUND: Adult spinal deformity (ASD) surgery often involves the placement of pedicle screws using various methods, including freehand technique, fluoroscopic guidance, and computer-assisted intraoperative navigation, each with distinct limitations. Particularly challenging is the instrumentation of pedicles with small or absent cancellous channels (Watanabe types C and D pedicles), commonly found at the apex of large curves where precise screw placement is crucial for effective deformity correction. 3D-printed pedicle screw drill guides (3DPSG) may assist in accurately placing pedicle screws while minimally disrupting the standard ASD surgery workflow. This study aims to evaluate the safety and efficacy of 3DPSG in ASD patients with Watanabe types C and D pedicles, where the safe corridor for screw placement is limited. METHODS: 3DPSG were designed using fine cut (≤1.25 mm) computed tomography scans. Preoperative screw trajectory planning and guide manufacturing were conducted using computer-aided design software (Mighty Oak Medical, Englewood, CO). Four ASD surgeons with varying experience levels placed the guides. Data on patient demographics, pedicle morphology, number of levels instrumented, and implant-related complications were collected. RESULTS: The study included 115 patients (median age 67, range 18-81 years) with 2210 screws placed from T1 to L5. The median number of levels instrumented per case was 11 (range 7-12). Diagnoses included adult degenerative scoliosis (n = 62), adult idiopathic scoliosis (n = 30), Scheuermann's kyphosis (n = 2), and other complex conditions (n = 21). The overall accuracy rate for pedicle screw placement was 99.5%, with a 0% malposition rate in type C and D pedicles. No vascular or neurological complications or reoperations related to screw placement were reported. CONCLUSION: 3DPSG facilitates safe and accurate pedicle screw placement regardless of pedicle morphology in ASD surgeries. This includes the challenging Watanabe types C and D pedicles, typically found at curve apices, enabling surgeons to achieve high implant density and optimal spinal fixation in ASD patients.

Radiographic outcomes and complications of anterior column realignment (ACR): a systematic review.

BACKGROUND: Anterior Column Realignment (ACR) was introduced to serve as a powerful segmental kyphosis correction technique in minimally invasive Adult Spinal Deformity (ASD) surgery. Releasing the Anterior Longitudinal Ligament (ALL) and annulus allows opening of the disc space to accommodate hyperlordotic cages. The overall safety and efficacy of ACR has been difficult to determine due to the heterogenicity of surgical techniques, complications reporting, and a paucity of published studies leading to preliminary and controversial conclusions. PURPOSE: To determine the efficacy and complications rates associated with ACR. STUDY DESIGN: Systematic review. METHODS: We queried the MEDLINE, Google Scholar, and EMBASE databases for all literature related to ACR procedure with a publication cutoff start date of January 1, 2010. This systematic review was performed utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. nonEnglish, nonhuman, case reports and review article publications were excluded. RESULTS: A total of 298 studies were identified. Following screening of title, abstract, and full text, 16 articles were included in the review with a total 756 patients. All the studies included in this systematic review were retrospective case series with a level of evidence IV. Ten studies reported ACR-related complications, with an average rate of 27.2%. The rate of reoperations was reported in 5 studies, for which the average reoperation rate was 9.5%. Cage Subsidence (CS) occurred in 13.7%, Proximal Junctional Kyphosis (PJK) in 12.2%, neurologic injury in 7.3%, and Proximal Junctional Failure (PJF) in 2.7%. The vascular injury rate was 0.5%, with bowel perforation and ureteric injury occurring in 0.2%. For the Patient Reported Outcome Measures (PROMs) and radiological outcome analysis we excluded studies with less than 12 months follow up leaving 8 studies eligible for the analysis. There was a significant improvement of both local Motion Segment Angle (MSA) and Intra Discal Angle (IDA) with a mean segmental correction of 20° lordosis in the 3 studies that reported these parameters. CONCLUSION: Based on the limited data available in this systematic review, the ACR technique has significant ability to restore and, when needed, correct the local segmental intervertebral angulation and thereby influencing the overall regional and global sagittal alignment. The associated risk of vascular, bowel, and nerve injury did not seem to be significantly higher in this review than other alternative lumbar interbody fusion techniques. Additional higher quality studies, including a consensus for reporting complications is required to reach definitive conclusions regarding its possible associated risks.

Antibiotic Use in Adult Spine Deformity Surgery: Results From the AO Spine Surveillance of the Management of Patients With Adult Spine Deformity.

STUDY DESIGN: Cross-sectional international survey with literature review. OBJECTIVES: To evaluate the evidence for these strategies and to understand the current trends in prophylactic antibiotic use during ASD surgery through an international survey. METHODS: An online survey was conducted among international AO Spine members regarding the peri-operative management of patients with ASD. The details of perioperative systemic and topical antibiotic use were solicited. Descriptive data were summarized for the responding surgeons who perform at least 10 long-segment fusions of >5 levels extending to the pelvis annually. RESULTS: The literature supports the use of prophylactic antibiotic effective against gram positive organisms. The use of topical vancomycin remains debated, and there is limited evidence for topical tobramycin use. A total of 116 responses were received. 74 (64%) surgeons use topical vancomycin, most usually deep to the fascia only 45 (61%). The most usual dose used is 1-2 g. 4 (3%) surgeons use topical tobramycin deep to fascia. Following surgery, 90 (78%) surgeons use prophylactic cephalosporin with 3 (3%) using cloxacillin, 5 (4%) using ciprofloxacin and 9 (8%) using vancomycin and 6 (5%) using clindamycin either in addition or alone. CONCLUSIONS: The present survey identifies a trend towards systemic and topical antibiotic prophylaxis primarily targeted at gram positive pathogens. The use of topical tobramycin, proposedly effective against gram negative infections, remains uncommon. There is a lack of consensus in the selection of perioperative antibiotic prophylaxis, thus a prospective study of the rates of infection with each strategy would be useful to inform guidelines.

The Role of Anterior Spine Surgery in Deformity Correction.

There are a range of anterior-based approaches to address flexible adult spinal deformity from the thoracic spine to the sacrum, with each approach offering access to a range of vertebral levels. It includes the transperitoneal (L5-S1), paramedian anterior retroperitoneal (L3-S1), oblique retroperitoneal (L1-2 to L5-S1), the thoracolumbar transdiaphragmatic approach (T9-10 to L4-5), and thoracotomy approach (T4-T12). The lumbar and lumbosacral spine is especially favorable for anterior-based approaches given the relative mobility of the peritoneal organs and position of the vasculature.

Postoperative coronal malalignment after adult spinal deformity surgery: incidence, risk factors, and impact on 2-year outcomes.

PURPOSE: To evaluate the incidence, risk factors, and patient-reported outcomes (PROs) of adult spinal deformity (ASD) patients with postoperative coronal malalignment. METHODS: A single-institution, retrospective cohort study of ASD patients undergoing ≥ 6 level fusions from 2015 to 2019 was undertaken. The primary outcome was postoperative coronal malalignment, defined as C7-coronal vertical axis (CVA) > 3 cm. Secondary outcomes included: complications, readmissions, reoperations, and 2-year PROs. RESULTS: A total of 243 ASD patients undergoing spinal surgery had preoperative and immediate postoperative measurements, and 174 patients (72%) had 2-year follow-up. Mean age was 49.3 ± 18.3yrs and mean instrumented levels was 13.5 ± 3.9. Mean preoperative CVA was 2.9 ± 2.7 cm, and 90 (37%) had preoperative coronal malalignment. Postoperative coronal malalignment occurred in 43 (18%) patients. Significant risk factors for postoperative coronal malalignment were: preoperative CVA (OR 1.21, p = 0.001), preoperative SVA (OR 1.05, p = 0.046), pelvic obliquity (OR 1.21; p = 0.008), Qiu B vs. A (OR 4.17; p = 0.003), Qiu C vs. A (OR 7.39; p < 0.001), lumbosacral fractional (LSF) curve (OR 2.31; p = 0.021), max Cobb angle concavity opposite the CVA (OR 2.10; p = 0.033), and operative time (OR 1.16; p = 0.045). Postoperative coronal malalignment patients were more likely to sustain a major complication (31% vs. 14%; p = 0.01), yet no differences were seen in readmissions (p = 0.72) or reoperations (p = 0.98). No significant differences were seen in 2-year PROs (p > 0.05). CONCLUSIONS: Postoperative coronal malalignment occurred in 18% of ASD patients and was most associated with preoperative CVA/SVA, pelvic obliquity, Qiu B/C curves, LSF curve concavity to the same side as the CVA, and maximum Cobb angle concavity opposite side of the CVA. Postoperative coronal malalignment was significantly associated with increased complications but not readmission, reoperation, or 2-year PROs.