Surgical outcome after treatment of thoracolumbar spinal stenosis in adults with achondroplasia.

PURPOSE: To describe the complications and the outcome of patients with achondroplasia undergoing thoracolumbar spinal surgery. METHODS: Retrospective analysis of prospectively collected data of all patients with achondroplasia undergoing surgery within the years 1992-2021 at the thoracic and/or lumbar spine. The outcome was measured by analyzing the surgical complications and revisions. The patient-rated outcome was assessed with the COMI score from 2005 onwards. RESULTS: A total of 15 patients were included in this study undergoing a total of 31 surgeries at 79 thoracolumbar levels. 12/31 surgeries had intraoperative complications consisting of 11 dural tears and one excessive intraoperative bleeding. 4/18 revision surgeries were conducted due to post-decompression hyperkyphosis. The COMI score decreased from 7.5 IQR 1.4 (range 7.1-9.8) preoperatively to 5.3 IQR 4.1 (2.5-7.5) after 2 years (p = 0.046). CONCLUSION: Patients with achondroplasia, the most common skeletal dysplasia condition with short-limb dwarfism, are burdened with a congenitally narrow spinal canal and are commonly in need of spinal surgery. However, surgery in these patients is often associated with complications, namely dural tears and post-decompression kyphosis. Despite these complications, patients benefit from surgical treatment at a follow-up of 2 years after surgery.

Patient-reported outcomes 1 and 2 years after transforaminal thoracic interbody fusion (TTIF).

STUDY DESIGN: Retrospective Cohort Study with prospectively collected data. PURPOSE: Transforaminal interbody fusion was initially designed for the lumbar spine. A similar approach was later introduced for the thoracic spine (TTIF). Here we report the surgical technique and the Core Outcome Measures Index (COMI) at 1-year and 2-year follow-ups, as well as the sagittal radiographic kyphosis correction of TTIF, achieved at 1 year and the latest follow-up. METHODS: All TTIF procedures from 2012 to 2020 were included. COMI scores were collected preoperatively and at 1- and 2-year follow-ups. The sagittal angle between the upper and lower endplates at the segment where TTIF was performed was measured on preoperative, 1-year postoperative, and last available radiographs. RESULTS: Seventy-nine TTIF procedures were performed for 64 patients (36% males; mean age 67.5 (SD 15.3) years). COMI score reduced from a mean value of 8.1 (SD 1.4) preoperatively to 4.7 (SD 2.7) at 1-year follow-up and 4.7 (SD 2.7) at 2-year follow-up. The mean correction of segmental kyphosis was 10.8 (SD 7.3, p < 0.0001) degrees at 1-year follow-up and 9.3 (SD 7.0, p < 0.0001) degrees at the final follow-up 3.4 (SD 1.4) years after the operation. Kaplan-Meier analysis for reoperations showed a 5-year survival of 91% (95% CI 0.795-1) for primary TTIF operations and survival of 77% (95% CI 0.651-0.899) for TTIFs performed after earlier fusion operations. CONCLUSIONS: TTIF is a feasible procedure in the thoracic spine. Kyphosis correction of approximately 10° was maintained at 1-year and final follow-up. Over 69% at 1-year and 61% at 2-year follow-up achieved MCID for COMI.

The use of the Core Yellow Flags Index for the assessment of psychosocial distress in patients undergoing surgery of the cervical spine.

BACKGROUND: Psychosocial distress (the presence of yellow flags) has been linked to poor outcomes in spine surgery. The Core Yellow Flags Index (CYFI), a short instrument assessing the 4 main yellow flags, was developed for use in patients undergoing lumbar spine surgery. This study evaluated its ability to predict outcome in patients undergoing cervical spine surgery. METHODS: Patients with degenerative spinal disorders (excluding myelopathy) operated in one centre, from 2015 to 2019, were asked to complete the CYFI at baseline and the Core Outcome Measures Index (COMI) at baseline and 3 and 12 months after surgery. The relationship between CYFI and COMI scores at baseline as well as the predictive ability of the CYFI on the COMI follow-up scores were tested using structural equation modelling. RESULTS: From 731 eligible patients, 547 (61.0 ± 12.5 years; 57.2% female) completed forms at all three timepoints. On a cross-sectional basis, preoperative CYFI and COMI scores were highly correlated (ß = 0.54, in men and 0.51 in women; each p < 0.001). CYFI added significantly and independently to the prediction of COMI at 3 months' FU in men (ß = 0.36) and 12 months' FU in men and women (both ß = 0.20) (all p < 0.001). CONCLUSION: The CYFI had a low to moderate but significant and independent association with cervical spine surgery outcomes. Implementing the CYFI in the preoperative workup of these patients could help refine outcome predictions and better manage patient expectations.

A decade of experience in over 300 surgically treated spine patients with long-term oral anticoagulation: a propensity score matched cohort study.

PURPOSE: The aim of this study was to investigate the risks and outcomes of patients with long-term oral anticoagulation (OAC) undergoing spine surgery. METHODS: All patients on long-term OAC who underwent spine surgery between 01/2005 and 06/2015 were included. Data were prospectively collected within our in-house Spine Surgery registry and retrospectively supplemented with patient chart and administrative database information. A 1:1 propensity score-matched group of patients without OAC from the same time interval served as control. Primary outcomes were post-operative bleeding, wound complications and thromboembolic events up to 90 days post-surgery. Secondary outcomes included intraoperative blood loss, length of hospital stay, death and 3-month post-operative patient-rated outcomes. RESULTS: In comparison with the control group, patients with OAC (n = 332) had a 3.4-fold (95%CI 1.3-9.0) higher risk for post-operative bleeding, whereas the risks for wound complications and thromboembolic events were comparable between groups. The higher bleeding risk was driven by a higher rate of extraspinal haematomas (3.3% vs. 0.6%; p = 0.001), while there was no difference in epidural haematomas and haematoma evacuations. Risk factors for adverse events among patients with OAC were mechanical heart valves, posterior neck surgery, blood loss > 1000 mL, age, female sex, BMI > 30 kg/m2 and post-operative PTT levels. At 3-month follow-up, most patients reported favourable outcomes with no difference between groups. CONCLUSION: Although OAC patients have a higher risk for complications after spine surgery, the risk for major events is low and patients benefit similarly from surgery.

Does loss to follow-up lead to an overestimation of treatment success? Findings from a spine surgery registry of over 15,000 patients.

PURPOSE: Patient-reported outcome measures (PROMs) are integral to the assessment of treatment success, but loss to follow-up (attrition) may lead to bias in the results reported. We sought to evaluate the extent, nature and implications of attrition in a long-established, single-centre spine registry. METHODS: The registry contained the data of 15,264 consecutive spine surgery patients. PROMs included the Core Outcome Measures Index (COMI) and a rating of the Global Treatment Outcome (GTO) and Satisfaction with Care. Baseline characteristics associated with returning a 12-month PROM (= "responder") were analysed (logistic regression). The 3-month outcomes of 12-month responders versus 12-month non-responders were compared (ANOVA and Chi-square). RESULTS: In total, 14,758/15,264 (97%) patients (60 ± 17y; 46% men) had consented to the use of their registry data for research. Preoperative, 3-month post-operative and 12-month post-operative PROMs were returned by 91, 90 and 86%, respectively. Factors associated with being a 12-month responder included: greater age, born in the country of the study, no private/semi-private insurance, better baseline status (lower COMI score), fewer previous surgeries, less comorbidity and no perioperative medical complications. 12-month non-responders had shown significantly worse outcomes in their 3-month PROMs than had 12-month responders (respectively, 66% vs 80% good GTO ("treatment helped/helped a lot"); 77% vs 88% satisfied/very satisfied; and 49% vs 63% achieved MCIC on COMI). CONCLUSION: Although attrition in this cohort was relatively low, 12-month non-responders displayed distinctive characteristics and their early outcomes were significantly worse than those of 12-month responders. If loss to follow-up is not addressed, treatment success will likely be overestimated, with erroneously optimistic results being reported.

Association between sagittal alignment and loads at the adjacent segment in the fused spine: a combined clinical and musculoskeletal modeling study of 205 patients with adult spinal deformity.

PURPOSE: Sagittal malalignment is a risk factor for mechanical complications after surgery for adult spinal deformity (ASD). Spinal loads, modulated by sagittal alignment, may explain this relationship. The aims of this study were to investigate the relationships between: (1) postoperative changes in loads at the proximal segment and realignment, and (2) absolute postoperative loads and postoperative alignment measures. METHODS: A previously validated musculoskeletal model of the whole spine was applied to study a clinical sample of 205 patients with ASD. Based on clinical and radiographic data, pre-and postoperative patient-specific alignments were simulated to predict loads at the proximal segment adjacent to the spinal fusion. RESULTS: Weak-to-moderate associations were found between pre-to-postop changes in lumbar lordosis, LL (r = - 0.23, r = - 0.43; p < 0.001), global tilt, GT (r = 0.26, r = 0.38; p < 0.001) and the Global Alignment and Proportion score, GAP (r = 0.26, r = 0.37; p < 0.001), and changes in compressive and shear forces at the proximal segment. GAP score parameters, thoracic kyphosis measurements and the slope of upper instrumented vertebra were associated with changes in shear. In patients with T10-pelvis fusion, moderate-to-strong associations were found between postoperative sagittal alignment measures and compressive and shear loads, with GT showing the strongest correlations (r = 0.75, r = 0.73, p < 0.001). CONCLUSIONS: Spinal loads were estimated for patient-specific full spinal alignment profiles in a large cohort of patients with ASD pre-and postoperatively. Loads on the proximal segments were greater in association with sagittal malalignment and malorientation of proximal vertebra. Future work should explore whether they provide a causative mechanism explaining the associated risk of proximal junction complications.

Revision surgery for incomplete resection or recurrence of cervical spine chordoma: a consecutive case series of 24 patients.

PURPOSE: Chordomas are rare tumors with an annual incidence of approximately one per million. Chordomas rarely metastasize but show a high local recurrence rate. Therefore, these patients present a major clinical challenge, and there is a paucity of the literature regarding the outcome after revision surgery of cervical spine chordomas. Available studies suggest a significantly worse outcome in revision scenarios. The purpose of this study is to analyze the survival rate, and complications of patients that underwent revision surgery for local recurrence or incomplete resection of chordoma at the craniocervical junction or at the cervical spine. METHODS: 24 consecutive patients that underwent revision surgery for cervical spine chordoma remnants or recurrence at a single center were reviewed retrospectively. We analyzed patient-specific surgical treatment strategies, complications, and outcome. Kaplan-Meier estimator was used to analyze five-year overall survival. RESULTS: Gross total resection was achieved in 17 cases. Seven patients developed dehiscence of the pharyngeal wall, being the most common long-term complication. No instability was observed. Postoperatively, four patients received proton beam radiotherapy and 12 patients had combined photon and proton beam radiotherapy. The five-year overall survival rate was 72.6%. CONCLUSION: With thorough preoperative planning, appropriate surgical techniques, and the addition of adjuvant radiotherapy, results similar to those in primary surgery can be achieved.

Association between the appropriateness of surgery, according to appropriate use criteria, and patient-rated outcomes after surgery for lumbar degenerative spondylolisthesis.

INTRODUCTION: Treatment failures in spine surgery are often attributable to poor patient selection and the application of inappropriate treatment. We used published appropriate use criteria (AUC) to evaluate the appropriateness of surgery in a large group of patients operated for lumbar degenerative spondylolisthesis (LDS) and to evaluate its association with outcome. METHODS: This was a retrospective analysis of prospectively collected outcome data from patients operated in our Spine Centre, 2005-2012. Appropriateness of surgery was judged based on the AUC. Patients had completed the multidimensional Core Outcome Measures Index (COMI) before surgery and at 3 months' and 1, 2 and 5 years' follow-up (FU). RESULTS: In total, 448 patients (69.8 ± 9.6 years; 323 (72%) women) were eligible for inclusion and the AUC could be applied in 393 (88%) of these. Surgery was considered appropriate (A) in 234 (59%) of the patients, uncertain/equivocal (U) in 90 (23%) and inappropriate (I) in 69 (18%). A/U patients had significantly (p < 0.05) greater improvements in COMI than I patients at each FU time point. The minimal clinically important change (MCIC) score for COMI was reached by 82% A, 76% U and 54% I patients at 1-year FU (p < 0.001, I vs A and U); the odds of achieving MCIC were 3-4 times greater in A/U patients than in I patients. CONCLUSIONS: The results suggest a relationship between appropriateness of surgery for LDS and the improvements in COMI score after surgery. The findings require confirmation in prospective studies that also include a control group of non-operated patients.

Validation of a surgical invasiveness index in patients with lumbar spinal disorders registered in the Spine Tango registry.

INTRODUCTION: Being able to quantify the invasiveness of a surgical procedure is important to weigh up its associated risks, since invasiveness governs the blood loss, operative time and likelihood of complications. Mirza et al. (Spine (Phila Pa 1976) 33:2651-2661, 2008) published an invasiveness index for spinal surgery. We evaluated the validity of a modified version of the Mirza invasiveness index (mMII), adapted for use with registry data. METHODS: A cross-sectional analysis was performed with data acquired from the Spine Tango registry including 21,634 patients. The mMII was calculated as the sum of six possible interventions on each vertebral level: decompression, fusion and stabilization either on anterior or posterior structures. The association between the mMII and blood loss, operative time and complications was evaluated using multiple regression, adjusting for possible confounders. RESULTS: The mean (± SD) mMII was 3.9 ± 5.0 (range 0-40). A 1-point increase in the mMII was associated with an additional blood loss of 12.8% (95% CI 12.6-13.0; p < 0.001) and an increase of operative time of 10.4 min (95% CI 10.20-10.53; p < 0.001). The R2 for the blood loss model was of 43% and for operative time, 47%. The mean mMII was significantly (p < 0.001) higher in patients with surgical complications (4.5 ± 5.6) and general medical complications (6.5 ± 7.0) compared to those without (3.8 ± 4.9). Our results were comparable to those reported in the original publication of Mirza et al. CONCLUSION: The mMII appeared to be a valid measure of surgical invasiveness in our study population. It can be used in predictor models and to adjust for surgical case-mix when comparing outcomes in different studies or different hospitals/surgeons in a registry.

Development of the "Core Yellow Flags Index" (CYFI) as a brief instrument for the assessment of key psychological factors in patients undergoing spine surgery.

BACKGROUND: Depression, anxiety, catastrophising, and fear-avoidance beliefs are key "yellow flags" (YFs) that predict a poor outcome in back patients. Most surgeons acknowledge the importance of YFs but have difficulty assessing them due to the complexity of the instruments used for their measurement and time constraints during consultations. We performed a secondary analysis of existing questionnaire data to develop a brief tool to enable the systematic evaluation of YFs and then tested it in clinical practice. METHODS: The following questionnaire datasets were available from a total of 932 secondary/tertiary care patients (61 ± 16 years; 51% female): pain catastrophising (N = 347); ZUNG depression (N = 453); Hospital Anxiety and Depression Scale (anxiety subscale) (N = 308); fear-avoidance beliefs (N = 761). The single item that best represented the full-scale score was identified, to form the 4-item "Core Yellow Flags Index" (CYFI). 2422 patients (64 ± 16 years; 54% female) completed CYFI and a Core Outcome Measures Index (COMI) before lumbar spine surgery, and a COMI 3 and 12 months later (FU). RESULTS: The item-total correlation for each item with its full-length questionnaire was: 0.77 (catastrophising), 0.67 (depression), 0.69 (anxiety), 0.68 (fear-avoidance beliefs). Cronbach's α for the CYFI was 0.79. Structural equation modelling showed CYFI uniquely explained variance (p < 0.001) in COMI at both the 3- and 12-month FUs (ß = 0.11 (women), 0.24 (men); and ß = 0.13 (women), ß = 0.14 (men), respectively). CONCLUSION: The 4-item CYFI proved to be a simple, practicable tool for routinely assessing key psychological attributes in spine surgery patients and made a relevant contribution in predicting postoperative outcome. CYFI's items were similar to those in the "STarT Back screening tool" used in primary care to triage patients into treatment pathways, further substantiating its validity. Wider use of CYFI may help improve the accuracy of predictive models derived using spine registry data.

Correction to: Surgical growth guidance with non-fused anchoring segments in early-onset scoliosis.

The preoperative X-ray presented in Figure 1 of the original publication erroneously was not the latest radiographic image taken before the index surgery at the age of 3 years.

Surgical growth guidance with non-fused anchoring segments in early-onset scoliosis.

PURPOSE: Surgical treatment of early-onset scoliosis (EOS) requires a balance between maintained curve correction and the capacity for spinal and thoracic growth. Spinal fusion creates irreversible conditions that prevent the implementation of further treatment methods. Our hypothesis was that non-fused anchors in growth guidance show a comparable outcome as the technique described in the literature, which involves spondylodesis of the anchoring segments. METHODS: This retrospective study analysed 148 surgeries in 22 EOS patients (11 female, 11 male) over a 15-year period. Patients underwent surgery with non-fused anchors and growth guidance techniques. Scoliosis, kyphosis, growth and anchoring segments were measured. For the latter, a new measuring technique was developed. Complications were recorded and classified. RESULTS: The mean Cobb angle reduced from 73.5 ± 24.4° to 28.4 ± 16.2° (60.2 ± 22.9%, p < 0.001) at the last follow-up. Spinal growth T1-S1 and T1-T12 were 41.1 ± 23.3 mm and 24.9 ± 16.6 mm (p < 0.001), respectively. Growth at the cranial and caudal anchoring segment was 1.5 mm/segment/year and 1.9 mm/segment/year, respectively. A total of 63 complications were documented in 20 patients, with 40 requiring unplanned revision surgery. Definitive spondylodesis was performed in three patients. CONCLUSION: Patients demonstrated a significant spinal growth including the anchoring segments. A comparable correction in Cobb angle and the type of complications was noted, although the rate of device-related complications was higher. No permanent impairment was reported. The rate of device-related complications is acceptable and outweighed by the significant degree of growth preservation and more flexible and individualised treatment strategy for patients with EOS. These slides can be retrieved under Electronic Supplementary Material.

Outcome of L5 radiculopathy after reduction and instrumented transforaminal lumbar interbody fusion of high-grade L5-S1 isthmic spondylolisthesis and the role of intraoperative neurophysiological monitoring.

PURPOSE: To evaluate the incidence and course of iatrogenic L5 radiculopathy after reduction and instrumented fusion of high-grade L5-S1 isthmic spondylolisthesis and the role of intraoperative neurophysiological monitoring (IONM). METHODS: Consecutive patients treated for high-grade spondylolisthesis with IONM from 2005 to 2013 were screened for eligibility. Prospectively collected clinical and surgical data as well as radiographic outcomes were analyzed retrospectively. Patients completed the multidimensional Core Outcome Measures Index (COMI) before and at 3, 12, and 24 months after surgery. RESULTS: Seventeen patients were included, with a mean age of 26.3 (±9.5) years. Mean preoperative L5-S1 slip was 72% (±21%) and was reduced to 19% (±13%) postoperatively. Mean loss of reduction at last follow-up [mean 19 months (±14, range 3-48 months)] was 3% (±4.3%). Rate of new L5 radiculopathy with motor deficit (L5MD) after surgery was 29% (five patients). Four patients fully recovered after 3 months, one patient was lost to neurologic follow-up. IONM sensitivity and specificity for postoperative L5MD was 20 and 100%, respectively. COMI, back pain and leg pain scores showed significant (p < 0.001) improvements at 3 months postoperatively, which were retained up to 24 months postoperatively. CONCLUSIONS: Transient L5 radiculopathy after reduction and instrumented fusion of high-grade spondylolisthesis is frequent. With IONM the risk of irreversible L5 radiculopathy is minimal. If IONM signal changes recover, full clinical recovery is expected within 3 months. Overall, patient-reported outcome of reduction and instrumented fusion of high-grade spondylolisthesis showed clinically important improvement.

The influence of cervical plate fixation with either autologous bone or cage insertion on radiographic and patient-rated outcomes after two-level anterior cervical discectomy and fusion.

PURPOSE: We aimed to identify technique-related factors influencing radiographic and patient-rated outcomes after two-level anterior cervical discectomy with fusion (ACDF) using either cage or autologous bone, with or without anterior plate fixation (APF). METHODS: This single center study was nested within the Eurospine Spine Tango data acquisition system. INCLUSION CRITERIA: consecutive two-level ACDF patients (2004-2012) presenting with signs of degenerative cervical radiculopathy or myelopathy. Before and 12 month postoperatively, patients completed the multidimensional Core Outcome Measures Index (COMI); at 12 months postoperatively they also rated the global treatment outcome (GTO) and their satisfaction with care. Cervical lordosis and segmental height were assessed radiographically preoperatively, immediately postoperatively, and at the last follow-up (LFU) (18.2 ± 13.3 months). RESULTS: One hundred and forty-four consecutive patients (113 with APF) were included. The use of APF versus stand-alone methods was associated with significantly increased segmental height (by 2.6 ± 2.6 versus 1.5 ± 2.4 mm, p = 0.04) and preservation of lordosis (by 2.7 ± 4.4° versus -1.7 ± 5°, p < 0.0001) at LFU, with comparable clinical outcome (COMI score reduction ≥3.1-point). Multiple regression controlling for potential confounders revealed that APF (p = 0.0004) and cage (p = 0.001) were associated with greater segmental height at LFU; APF was associated with a greater lordosis angle at LFU (p < 0.0001). Greater increase in segmental height at LFU (p = 0.02) was associated with a better GTO. CONCLUSIONS: Adding APF was associated with greater segmental height and preservation of lordosis in two-level ACDF, especially using bone autograft, but also for cage. Clinical outcome was comparable for all groups. Though the surgical technique per se did not determine clinical outcome, patients achieving a greater segmental height difference showed a significantly better GTO.

Lumbar facet joint effusion on MRI as a sign of unstable degenerative spondylolisthesis: should it influence the treatment decision?

STUDY DESIGN: Retrospective study. OBJECTIVE: To examine whether the outcomes of decompression alone (D) or decompression with fusion (D&F) differed depending on the presence or absence of the facet effusion sign in degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: There is ongoing discussion as to whether D&F is superior to D in the surgical treatment of patients with lumbar degenerative spondylolisthesis (LDS) and symptoms of spinal or radicular claudication. Previous studies have shown that a positive facet joint effusion sign on magnetic resonance imaging correlates with the spontaneous reduction of slip when comparing upright and supine postures and might represent a sign of instability, guiding treatment decisions. PATIENTS AND METHODS: One hundred sixty patients [age 69 (SD 10) y; 119 women, 41 men] with a diagnosis of LDS were identified retrospectively from our Spine Center Registry (linked to the Eurospine, Spine Society of Europe Spine Tango Registry). They were categorized based on the presence/absence of the facet effusion sign and the type of treatment received. Forty-four patients had effusion and underwent D; 76 effusion and D&F; 19 no effusion and D; and 21 no effusion and D&F. Before surgery and 3, 12, and 24 months after surgery, patients completed the multidimensional Core Outcome Measures Index questionnaire. At follow-up, they rated the global treatment outcomes (1-5 scale). Multiple regression analyses evaluated the factors influencing the outcomes. RESULTS: When age and sex was controlled for, there was no significant difference in outcomes dependent on the presence of the facet effusion sign and/or the treatment received (D vs. D&F). CONCLUSIONS: Although mindful of the limitations of this retrospective study, we conclude that the effusion sign alone does not seem to be an indication for adding fusion to decompression in the treatment of LDS. Hence, the presence of the facet effusion sign should not, in itself, deter the surgeon from performing decompression alone. However, the phenomenon should be investigated in larger samples of patients, ideally within a randomized trial.

A comparative effectiveness study of patient-rated and radiographic outcome after 2 types of decompression with fusion for spondylotic myelopathy: anterior cervical discectomy versus corpectomy.

OBJECT: Both anterior cervical discectomy with fusion (ACDF) and anterior cervical corpectomy with fusion (ACCF) are used to treat cervical spondylotic myelopathy; however, there is currently no evidence for the superiority of one over the other in terms of patient-rated outcomes. This comparative effectiveness study compared the patient-rated and radiographic outcomes of 2-level ACDF versus 1-level ACCF. METHODS: This single-center study was nested within the EuroSpine Spine Tango data acquisition system. Inclusion criteria were the following: consecutive patients presenting with signs of cervical spondylotic myelopathy who underwent 2-level ACDF or 1-level ACCF between 2004 and 2011. Before and 12 months after surgery, patients completed the multidimensional Core Outcome Measures Index (COMI) and also rated global treatment outcome and satisfaction with care on 5-point Likert scales. Cervical lordosis, segmental height, and fusion rate were assessed radiographically before and immediately after surgery and at the last follow-up (20.4 ± 13.7 months, mean ± SD). RESULTS: In total, 118 consecutive patients (80 in the ACDF group and 38 in the ACCF group) were included. Age, sex, comorbidity, baseline symptoms, baseline radiographic data, operation duration, and complication rates did not differ significantly between the 2 groups. Blood loss was significantly (p < 0.04) lower in the ACDF group. Postoperative mean segmental height was significantly (p = 0.0006) greater for ACDF (42.0 ± 4.2 mm, mean ± SD) than for ACCF (39.0 ± 4.0 mm), and global average lordosis improved to a significantly (p = 0.003) greater extent in ACDF (by 1.6° ± 4.1°) than in ACCF (by -1.0° ± 4.0°). Fusion rates for ACDF were 97.5% and for ACCF were 94.7% (p = 0.59). The 12-month patient-rated outcomes did not differ significantly between ACDF and ACCF: 82.4% and 68.6% had a good global outcome (operation helped/helped a lot) (p = 0.10), 86.5% and 82.9% were satisfied/very satisfied with care (p = 0.62), and the reduction in the multidimensional COMI was 2.8 ± 2.7 and 2.2 ± 3 points (p = 0.30), respectively. The postoperative increase in lordosis angle showed low but significant correlations with the improvement in arm pain (r = 0.25, p = 0.014), highest pain (r = 0.25, p = 0.013), and function (r = 0.24, p = 0.016). CONCLUSIONS: Both ACDF and ACCF are safe and effective in the treatment of cervical spondylotic myelopathy, indicated by similarly good patient-rated outcomes 1 year after surgery. This precludes any conclusions regarding the superiority of one technique over the other, although it should be noted that ACDF resulted in less blood loss and greater improvements in cervical lordosis and segmental height than ACCF. Patients with improved lordosis angle had a better clinical outcome.

Far Lateral Lumbar Decompression Using the Far-Lateral Approach: Patient Reported Outcome is Associated with the Involved Vertebral Level and Coronal Segmental Angle.

STUDY DESIGN: Single centre retrospective study of prospectively collected data. OBJECTIVE: Analyse factors associated with patient reported outcome after far lateral decompression surgery (FLDS) for lumbar nerve root compression using the far-lateral approach. SUMMARY OF BACKGROUND DATA: To date, no studies have investigated the influence of vertebral level, coronal segmental Cobb angle, and the nature of the compressive tissue (hard/soft) on patient reported outcome following FLDS. METHODS: Patients who had undergone FLDS between 2005 and 2020 were included. Coronal segmental angle (CSCA) was measured on preoperative, posteroanterior radiographs. Primary outcome measure was the Core Outcome Measures Index (COMI) score at 2 years' follow-up (2Y-FU). Patients who had undergone microsurgical decompression using a midline approach (MID) served as a comparator group. RESULTS: There were 148 FLDS and 463 MID patients. In both groups there was a significant improvement in COMI score from preoperative to 2Y-FU (P<0.0001), with greater improvement in patients treated at higher vertebral levels than in those treated at L5/S1 (P=0.014). Baseline COMI, ASA grade, BMI, and low back pain as the "chief complaint" all had a significant association with the 2-year COMI score. The nature of compressive tissue showed no association with COMI score at 2Y-FU. In the FLDS group, there was a statistically significant correlation between the preoperative CSCA and change in COMI score preoperatively to 2Y-FU (P<0.001). The association was retained in multiple regression analysis controlling for confounders. A one-degree increase in CSCA was associated with a 0.35-point worse COMI score at 2Y-FU (P=0.003). CONCLUSION: Treatment of far lateral nerve root compression showed overall good patient reported outcome, but with less improvement with advanced coronal segmental angulation. Modified approaches and techniques might be preferable for the level L5/S1.

Lumbar facet joint effusion in MRI: a sign of instability in degenerative spondylolisthesis?

PURPOSE: The term "segmental instability" of the lumbar spine is not clearly defined, especially as it relates to degenerative spondylolisthesis (DS) and rotational translation (RT). We investigated whether facet joint effusion on conventional supine MRI indicated increased abnormal motion in DS and RT. METHODS: 160 patients (119 female, 41 male, mean age 68.8 years, range 38.8-89.3 years) who had undergone decompression only or decompression with instrumented fusion for degenerative spondylolisthesis with different degrees of narrowing of the spinal canal were identified retrospectively from our spine surgery database. All had preoperative upright X-rays in AP and lateral views as well as supine MRI. The imaging studies were assessed for the following parameters: percent of slippage, absolute value of facet joint effusion, facet angles, degree of facet degeneration and spinal canal central narrowing, disc height, presence of facet cysts and the presence of rotational translation in the AP X-ray. RESULTS: 40/160 patients showed no facet joint effusion, and in these the difference in the values for the % slip on upright X-ray and % slip on supine MRI was ≤3%. A further 12 patients also showed a difference ≤3%, but had some fluid in the joints (0.44 ± 0.38 mm). In 108 patients, the difference in the % slip measured on X-ray and on MRI was >3% (mean 10.6%, range 4-29%) and was associated with a mean facet effusion size of 2.15 ± 0.85 mm. The extent of effusion correlated significantly with the relative slippage difference between standing and supine positions (r = 0.64, p < 0.001), and the extent of the left/right difference in effusion was associated with the presence of rotational translation (RT 1.31 ± 0.8 mm vs. no-RT 0.23 ± 0.17 mm, p < 0.0001). CONCLUSIONS: Facet joint effusion is clearly correlated with spontaneous reduction of the extent of slippage in the supine position compared to the upright position. Also, the greater the difference in right and left facet effusion, the higher the likelihood of having a RT. Future studies should assess whether analysis of facet joint effusion measured on routine MRI can help in decision-making regarding the optimal surgical treatment to be applied (decompression alone or combined with fusion).

Prospective study of the effect of pedicle screw placement on development of the immature vertebra in an in vivo porcine model.

INTRODUCTION: There is increasing awareness of the need for pedicle screw constructs in the treatment of spinal deformities in very young children. However, the long-term effects of pedicle screws on the immature spine are still unclear. We used a porcine model to analyze the morphological changes of the spinal canal and vertebral body in response to the placement of pedicle screws. METHODS: 13 newborn pigs were operated on. Each pig received a single pedicle screw at the L2 level. After a tenfold increase in body weight (7 months later), the symmetry of the spinal canal and vertebral body was measured on CT scans of the investigational (L2) and control (L3) levels in terms of the angulations of the instrumented and non-instrumented halves of the vertebral body and spinal canal. RESULTS: After 7 months, the normalised vertebral body angle had reduced on the non-screw side and increased on the screw side, indicating asymmetry in vertebral body growth in the axial plane. The difference was significant (p = 0.009). However, there was no significant difference between the screw and non-screw sides for the spinal canal angles at the L2 level at either the intraoperative or 7-month follow-up assessment (each p > 0.05). CONCLUSIONS: Pedicle screws in the immature porcine spine have a significant effect on the development of the vertebral body. However, in the present study, no corresponding alteration of the morphology of the spinal canal was observed. Our results provide further support for the existing arguments in favour of pedicle screws when weighing up the many factors to be considered in creating a treatment plan for early onset scoliosis.