102 lumbar pedicle subtraction osteotomies: one surgeon’s learning curve

Learning curve analyses in spine surgery: a systematic simulation-based critique of methodologies

BACKGROUND CONTEXT

Various statistical approaches exist to delineate learning curves in spine surgery. Techniques range from dividing cases into intervals for metric comparison, to employing regression and cumulative summation (CUSUM) analyses. However, their inherent inconsistencies and methodological flaws limit their comparability and reliability.

PURPOSE

To critically evaluate the methodologies used in existing literature for studying learning curves in spine surgery and to provide recommendations for future research.

STUDY DESIGN

Systematic literature review.

METHODS

A comprehensive literature search was conducted using PubMed, Embase, and Scopus databases, covering articles from January 2010 to September 2023. For inclusion, articles had to evaluate the change in a metric of performance during human spine surgery across time/a case series. Results had to be reported in sufficient detail to allow for evaluation of individual performance rather than group/institutional performance. Articles were excluded if they included cadaveric/nonhuman subjects, aggregated performance data or no way to infer change across a number of cases. Risk of bias was assessed using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool. Surgical data were simulated using Python 3 and then examined via multiple commonly used analytic approaches including division into consecutive intervals, regression and CUSUM techniques. Results were qualitatively assessed to determine the effectiveness and limitations of each approach in depicting a learning curve.

RESULTS

About 113 studies met inclusion criteria. The majority of the studies were retrospective and evaluated a single-surgeon's experience. Methods varied considerably, with 66 studies using a single proficiency metric and 47 using more than 1. Operating time was the most commonly used metric. Interval division was the simplest and most commonly used method yet inherent limitations prevent collective synthesis. Regression may accurately describe the learning curve but in practice is hampered by sample size and model choice. CUSUM analyses are of widely varying quality with some being fundamentally flawed and widely misinterpreted however, others provide a reliable view of the learning process.

CONCLUSION

There is considerable variation in the quality of existing studies on learning curves in spine surgery. CUSUM analyses, when correctly applied, offer the most reliable estimates. To improve the validity and comparability of future studies, adherence to methodological guidelines is crucial. Multiple or composite performance metrics are necessary for a holistic understanding of the learning process.

Lumbar pedicle subtraction osteotomy: techniques and outcomes

Pedicle subtraction osteotomy has been thoroughly described and studied over the past 2 decades, being applied mainly in the lumbar spine, followed by the thoracic spine. Our better understanding of alignment biomechanics, and the progressive refinements of the surgical technique over time made it a very efficient procedure for the management of fixed sagittal malalignment. However, a long learning curve is mandatory to mitigate the associated risks particularly neurological deficits and achieve satisfactory clinical and radiological outcomes with an acceptable rate of complications.

The Case for Operative Efficiency in Adult Spinal Deformity Surgery: Impact of Operative Time on Complications, Length of Stay, Alignment, Fusion Rates, and Patient-Reported Outcomes

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To analyze the impact of operative room (OR) time in adult spinal deformity (ASD) surgery on patient outcomes.

BACKGROUND

It is currently unknown if OR time in ASD patients matched for deformity severity and surgical invasiveness is associated with patient outcomes.

MATERIALS AND METHODS

ASD patients with baseline and two-year postoperative radiographic and patient-reported outcome measures (PROM) data, undergoing a posterior-only approach for long fusion (>L1-Ilium) were included. Patients were grouped into short OR time (<40th percentile: <359 min) and long OR time (>60th percentile: >421 min). Groups were matched by age, baseline deformity severity, and surgical invasiveness. Demographics, radiographic, PROM data, fusion rate, and complications were compared between groups at baseline and two years follow-up.

RESULTS

In total, 270 patients were included for analysis: the mean OR time was 286 minutes in the short OR group versus 510 minutes in the long OR group ( P <0.001). Age, gender, percent of revision cases, surgical invasiveness, pelvic incidence minus lumbar lordosis, sagittal vertical axis, and pelvic tilt were comparable between groups ( P >0.05). Short OR had a slightly lower body mass index than the short OR group ( P <0.001) and decompression was more prevalent in the long OR time ( P =0.042). Patients in the long group had greater hospital length of stay ( P =0.02); blood loss ( P <0.001); proportion requiring intensive care unit ( P =0.003); higher minor complication rate ( P =0.001); with no significant differences for major complications or revision procedures ( P >0.5). Both groups had comparable radiographic fusion rates ( P =0.152) and achieved improvement in sagittal alignment measures, Oswestry disability index, and Short Form-36 ( P <0.001).

CONCLUSION

Shorter OR time for ASD correction is associated with a lower minor complication rate, a lower estimated blood loss, fewer intensive care unit admissions, and a shorter hospital length of stay without sacrificing alignment correction or PROMs. Maximizing operative efficiency by minimizing OR time in ASD surgery has the potential to benefit patients, surgeons, and hospital systems.

Specialty Impact on Patient Outcomes: Paving a Way for an Integrated Approach to Spinal Disorders

Spinal surgical procedures are steadily increasing globally due to broad indications of certain techniques encompassing a wide spectrum of conditions, including degenerative spine disorders, congenital anomalies, spinal metastases, and traumatic spinal fractures. The two specialties, neurosurgery (NS) and orthopedic surgery (OS), both possess the clinical adeptness to perform these procedures. With the advancing focus on comparative effectiveness research, it is vital to compare patient outcomes in spine surgeries performed by orthopedic surgeons and neurosurgeons, given their distinct approaches and training backgrounds to guide hospital programs and physicians to consider surgeon specialty when making informed decisions. Our review of the available literature revealed no significant difference in postoperative outcomes in terms of blood loss, neurological deficit, dural injury, intraoperative complications, and postoperative wound dehiscence in procedures performed by neurosurgeons and orthopedic surgeons. An increase in blood transfusion rates among patients operated by orthopedic surgeons and a longer operative time of procedures performed by neurosurgeons was a consistent finding among several studies. Other findings include a prolonged hospital stay, higher hospital readmission rates, and lower cost of procedures in patients operated on by orthopedic surgeons. A few studies revealed lower sepsis rates unplanned intubation rates and higher incidence of urinary tract infections (UTIs) and pneumonia postoperatively among patient cohorts operated by neurosurgeons. Certain limitations were identified in the studies including the use of large databases with incomplete information related to patient and surgeon demographics. Hence, it is imperative to account for these confounding variables in future studies to alleviate any biases. Nevertheless, it is essential to embrace a multidisciplinary approach integrating the surgical expertise of the two specialties and develop standardized management guidelines and techniques for spinal disorders to mitigate complications and enhance patient outcomes.

Learning Curve and Clinical Outcomes of Ultrasonic Osteotome-based En Bloc Laminectomy for Thoracic Ossification of the Ligamentum Flavum

OBJECTIVE

Despite rapid advances in minimally invasive surgery, en bloc laminectomy remains the most common surgical approach for treating thoracic ossification of the ligamentum flavum (TOLF). However, the learning curve of this risky operation is rarely reported. Therefore, we aimed to describe and analyze the learning curve of ultrasonic osteotome-based en bloc laminectomy for TOLF.

METHODS

Among 151 consecutive patients with TOLF who underwent en bloc laminectomy performed by one surgeon between January 2012 and December 2017, we retrospectively analyzed their demographic data, surgical parameters, and neurological function. Neurological outcome was evaluated with the modified Japanese Orthopaedic Association (mJOA) scale, and the Hirabayashi method was used to calculate the neurological recovery rate. The learning curve was assessed with logarithmic curve-fitting regression analysis. Univariate analysis methods were used for statistical analysis, including t-test, rank sum test, and chi-square test.

RESULTS

A total of 50% of learning milestones could be reached in approximately 14 cases, and the asymptote in 76 cases. Therefore, 76 of the 151 enrolled patients were defined as the "early group," and the remaining 75 were delimitated as the "late group" for comparison. There was a significant intergroup difference in the corrected operative time (94.80 ± 27.77 vs 65.93 ± 15.67 min, P < 0.001) and the estimated blood loss (median 240 vs 400 mL, P < 0.001). The overall follow-up was 83.1 ± 18.5 months. The mJOA significantly increased from a median of 5 (IQR: 4-5) before the surgery to 10 (IQR: 9-10) at the last follow-up (P < 0.001). The overall complication rate was 37.1%, and no significant intergroup difference was found, except for the incidence of dural tears (31.6% vs 17.3%, p = 0.042).

CONCLUSION

Initially, mastering the en bloc laminectomy technique using ultrasonic osteotome for TOLF treatment can be challenging, but the surgeon's experience improves as the operative time and blood loss decrease. Improved surgical experience reduced the risk of dural tears but was not associated with the overall complication rate or long-term neurological function. Despite the relatively long learning curve, en bloc laminectomy is a secure and valid technique for TOLF treatment.

3D-Printed Guide Plate System-Assisted Thoracolumbar Kyphosis Osteotomy: A Technical Case Series

OBJECTIVE

This paper reports a new three-dimensional (3D)-printed osteotomy guidance system to assist thoracolumbar kyphosis osteotomy and describe the guide plate design, surgical procedure, and short-term clinical results.

METHODS

The computer-aided design software reconstructs the 3D model of the spinal deformity region using the computed tomography data of the patient and plans the correction angle according to the deformity. The guide plate design described in previous experimental studies was used and optimized before clinical application. The lamina positioning, lamina osteotomy, and vertebral osteotomy guides were designed, and three 3D guides with different functions were used to assist osteotomy.

RESULTS

Seven patients successfully underwent osteotomy under the guidance of a 3D guide plate. Kyphosis was corrected to different degrees without serious complications. At the last follow-up, the back pain and nerve function of 7 patients were improved to varying degrees and the internal fixation without displacement and fracture.

CONCLUSIONS

The preliminary clinical application of the new 3D osteotomy guidance system shows that it provides an effective connection between the guide plates and a clinically operative visual field. The use of a 3D guide plate system for positioning and guidance is helpful to complete preoperative planning of anterior and middle column vertebral body osteotomy. However, the efficacy of this method should be compared to that of the free-hand technique with long-term follow-up.

Factors influencing complications after 3-columns spinal osteotomies for fixed sagittal imbalance from multiple etiologies: a multicentric cohort study about 286 cases in 273 patients

PURPOSE

Spinal osteotomies performed to treat fixed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for fixed sagittal imbalance from multiple etiologies.

METHODS

The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicenter cohort of patients who underwent 3-columns (3C) spinal osteotomy, between January 2010 and January 2017. Clinical and radiological data were compared pre- and post-operatively. Complications and their risk factors were analyzed.

RESULTS

Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1 year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were significantly improved (p < 0.001). A total of 164 patients (59.2%) experienced at least 1 complication (277 complications). Complications-free survival rates were only 30% at 5 years. Most of those were mechanical (35.2%), followed by general (17.6%), surgical site infection (17.2%) and neurological (10.9%). Pre-operative neurological status [RR = 2.3 (1.32-4.00)], operative time (+ 19% of risk each additional hour) and combined surgery [RR = 1.76 (1.08-2.04)] were assessed as risk factors for overall complication (p < 0.05). The use of patient-specific rods appeared to be significantly associated with less overall complications [RR = 0.5 (0.29-0.89)] (p = 0.02).

CONCLUSION

Spinal 3C osteotomies were efficient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

Osteotomies for the Treatment of Adult Spinal Deformities: A Critical Analysis Review

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Spinal osteotomies are powerful deformity correction techniques that may be associated with serious complications.

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The anatomical spinal osteotomy classification system proposes 6 grades of resection corresponding to different anatomic bone, disc, facet, and ligament interventions.

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Surgeons should be aware of the nuances of 3-column osteotomies with regard to spinal level selection, construct composition, and posterior column reconstruction and closure techniques.

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There is a global tendency toward avoiding 3-column osteotomies as much as possible because of the growing evidence regarding the effectiveness of posterior column osteotomies and halo-gravity traction.

Impact of Surgeon Experience on Outcomes of Anterior Cervical Discectomy and Fusion

INTRODUCTION

The relationship between surgeon experience and cervical fusion outcomes has yet to be assessed. We investigate perioperative characteristics, patient-reported outcomes (PROMs), and minimal clinically important difference (MCID) achievement after anterior cervical diskectomy and fusion (ACDF) by the volume of cases done throughout an orthopaedic spine surgeon's career.

METHODS

ACDF procedures between 2005 and 2020 were identified. Group I included the first half of ACDF cases (#1-#321). PROMs were introduced in the second half of the ACDF cases; thus, the next 322 cases were subdivided to compare PROM and MCID between subgroups (cases #322 to #483 = group II and #484 to #645 = group III). PROMs, including VAS back/leg, Oswestry Disability Index (ODI), Short Form-12 Physical Composite Score, and PROMIS-PF, were collected preoperatively/postoperatively. Demographics, perioperative variables, mean PROMs, and MCID achievement were compared between groups and subgroups using the Student t-test and chi-square. Logistic regression evaluated MCID achievement using the established threshold values.

RESULTS

A total of 642 patients were included (320 in group I, 161 in group II, and 161 in group III). The latter cases had significantly decreased surgical time, blood loss, and postoperative length of stay in comparison of groups and subgroups (P ≤ 0.002, all). CT-confirmed 1-year arthrodesis rates were increased among the latter cases (P = 0.045). Group II had significantly higher arthrodesis rates than group III (P = 0.039). The postoperative complication rates were lower in the latter cases (P < 0.001, all), whereas subgroup analysis revealed lower incidence of urinary retention and other complications in group III (P ≤ 0.031, all). Mean PROMs were significantly inferior in group II versus group III for VAS neck at 6 months (P = 0.030), Neck Disability Index at 6 months preoperatively (P ≤ 0.022, both), Short Form-12 Physical Composite Score at 12 weeks/2 years (P ≤ 0.047, both), and PROMIS-PF at 12 weeks/6 months (P ≤ 0.036, both). The MCID attainment rates were higher among group III for VAS neck/Neck Disability Index at 2 years (P ≤ 0.005) and overall achievement across all PROMs (P ≤ 0.015, all).

DISCUSSION

Increased ACDF case volume may lead to markedly decreased surgical time, blood loss, and length of postoperative stay as well as improved clinical outcomes in pain, disability, and physical function.

Dual attending surgeon strategy learning curve in single-staged posterior spinal fusion (PSF) surgery for 415 idiopathic scoliosis (IS) cases

BACKGROUND CONTEXT

The implementation of a dual attending surgeon strategy had improved perioperative outcomes of idiopathic scoliosis (IS) patients. Nevertheless, the learning curve of a dual attending surgeon practice in single-staged posterior spinal fusion (PSF) surgery has not been established.

OBJECTIVE

To evaluate the surgical learning curve of a dual attending surgeon strategy in IS patients.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

415 IS patients (Cobb angle <90°) who underwent PSF using a dual attending surgeon strategy OUTCOME MEASURES: Primary outcomes included operative time, total blood loss, allogenic blood transfusion requirement, length of hospital stay and perioperative complication rate.

METHODS

Regression analysis using Locally Weighted Scatterplot Smoothing (LOWESS) method was applied to create the best-fit-curve between case number versus operative time and total blood loss in identifying cut-off points for the learning curve.

RESULTS

The mean Cobb angle was 60.8±10.8°. Mean operative time was 134.4±32.1 minutes and mean total blood loss was 886.0±450.6 mL. The mean length of hospital stay was 3.0±1.6 days. The learning curves of a dual attending surgeon strategy in this study were established at the 115th case (operative time) and 196th case (total blood loss) respectively (p<.001). In comparison of cases before and after the cut-off points, mean operative time reduced significantly from 147.2±36.5 minutes to 129.5±28.9 minutes and mean total blood loss reduced significantly from 1015.1±506.6 mL to 770.4±357.3 mL (p<.001). No allogenic blood transfusion was required and there were 7 perioperative complications (n=7/415, 1.7%) recorded.

CONCLUSION

The learning curve of a dual surgeon strategy in single-staged PSF surgery based on operative time and total blood loss were established at 115th case and 196th case respectively (p<.001).

Learning Curve for a Dual Attending Surgeon Strategy in Posterior Spinal Fusion (PSF): An Analysis of 105 Severe Adolescent Idiopathic Scoliosis Patients (Cobb Angle ≥90°)

STUDY DESIGN

Retrospective study.

OBJECTIVE

To assess the learning curve of a dual attending surgeon strategy in severe adolescent idiopathic scoliosis patients.

SUMMARY OF BACKGROUND DATA

The advantages of a dual attending surgeon strategy in improving the perioperative outcome in scoliosis surgery had been reported. However, the learning curve of this strategy in severe scoliosis had not been widely studied.

METHODS

A total of 105 patients with adolescent idiopathic scoliosis with Cobb angle of 90° or greater, who underwent posterior spinal fusion using a dual attending surgeon strategy were recruited. Primary outcomes were operative time, total blood loss, allogeneic blood transfusion requirement, length of hospital stay from time of operation and perioperative complications. Cases were sorted chronologically into group 1: cases 1 to 35, group 2: cases 36 to 70, and group 3: case 71 to 105. Mean operative time (≤193.3 min), total blood loss (≤1612.2 mL), combination of both and allogeneic blood transfusion were the selected criteria for receiver operating characteristic analysis of the learning curve.

RESULTS

The mean Cobb angle was 104.5° ± 12.3°. The operative time, total blood loss, and allogeneic blood transfusion requirement reduced significantly for group 1 (220.6 ± 54.8 min; 2011.3 ± 881.8 mL; 12 cases) versus group 2 (183.6 ± 36.7 min; 1481.6 ± 1035.5 mL; 3 cases) and group 1 versus group 3 (175.6 ± 38.4 min; 1343.7 ± 477.8 mL; 3 cases) (P < 0.05). There were six perioperative complications. Fifty-seven cases were required to achieve the preset criteria (mean operative time and mean total blood loss) (area under the curve 0.740; P < 0.001; sensitivity 0.675; specificity 0.662).

CONCLUSION

There was significant improvement in operative time and total blood loss when comparing group 1 versus group 2 and group 1 versus group 3. The cut-off point for the learning curve was 57 cases when the preset criteria were fulfilled (≤193.3 min operative time and ≤1612.2 mL of total blood loss).Level of Evidence: 4.

Flexing a standard hinge-powered operating table for lumbosacral three-column osteotomy (3-CO) site closure in 84 consecutive patients

Three-column osteotomy (3-CO) is a powerful technique in adult deformity surgery, and pedicle subtraction osteotomy (PSO) is the workhorse to correct severe kyphotic spinal deformities. Aging of the population, increasing cases of iatrogenic flat back deformities and understanding the importance of sagittal balance have led to a dramatic increase of this surgical technique. Surgery, however, is demanding and associated with high complication rates so that every step of the procedure requires meticulous technique. Particularly, osteotomy closure is associated with risks like secondary fracture, translation, or iatrogenic stenosis. This step is traditionally performed by compression or a cantilever maneuver with sometimes excessive forces on the screws or instrumentation. Implant loosening or abrupt subluxation resulting in construct failure and/or neurological deficits can result. The aim of this prospective registry study was to assess the efficacy and safety of our surgical PSO technique as well as the osteotomy closure by flexing a hinge-powered OR table. In a series of 84 consecutive lumbosacral 3-CO, a standardized surgical technique with special focus on closure of the osteotomy was prospectively evaluated. The surgical steps with the patients positioned prone on a soft frame are detailed. Osteotomy closure was achieved by remote controlled bending of a standard OR table without compressive or cantilever forces in all 84 cases. This technique carries a number of advantages, particularly the reversibility and the slow speed of closure with minimum force. There was not a single mechanical intraoperative complication such as vertebral body fracture, subluxation, or adjacent implant loosening during osteotomy closure, compared to external cohorts using the cantilever technique (p = 0.130). The feasibility of controlled 3-CO closure by flexing a standard OR table is demonstrated. This technique enables a safe, gentle closure of the osteotomy site with minimal risk of implant failure or accidental neurological injury.

Surgeon experience influences patient characteristics and outcomes in spine deformity surgery

PURPOSE

To characterize differences in patient demographics and outcomes by surgeon experience in a cohort of patients undergoing adult spinal deformity surgery.

METHODS

Patients undergoing degenerative spinal deformity were included. Patients whose surgeons graduated from fellowship ≤ 5 years prior to surgery versus > 5 years were compared. Multivariable linear and logistic regression, controlling for age, sex, comorbidity burden, number of segments fused, blood loss and operative time were used to evaluate differences in outcomes. Characteristics of operative invasiveness were plotted against surgeons' level of experience, and trends in these measures were assessed with univariate linear regression.

RESULTS

Three-hundred sixty-three patients were included. 147 patients' surgeons had ≤ 5 years of experience. Patient demographics were evenly matched. Patients with junior surgeons had more pre-existing medical complications, and senior surgeons were less likely to take care of patients with Medicare/Medicaid (p < 0.001). Junior surgeons were more likely to operate on non-elective patients (p < 0.001). Patients of junior surgeons received larger fusions (9.6 vs. 7.6 segments fused, p < 0.001). There were no differences in complication rates or death. Patients of junior surgeons had longer overall length of stays (p = 0.037) and higher rates of nonhome discharge (OR 2.0, p < 0.001), 30- and 90-day (p < 0.005) ED visits, and higher costs (+ $8548, 95% CI: $1596 to $15,502; p = 0.016).

CONCLUSION

Junior surgeons tend to perform more extensive deformity operations on more medically complex patients compared to senior surgeons, associated with higher costs and more resource utilization than senior surgeons.

State of the art review: Vertebral Osteotomies for the management of Spinal Deformity

Spinal deformity is a complex condition caused by various etiologies (degenerative, neuromuscular, congenital, developmental, traumatic, neoplastic, idiopathic) leading to clinical deformity, axial back pain, and neurologic deficits. Patients presenting with severe deformities require vertebral osteotomies to achieve the necessary curve correction for radiographic and clinical improvement. The three major vertebral osteotomy techniques commonly used at this time are the posterior column osteotomy (PCO), pedicle subtraction osteotomy (PSO), and vertebral column resection (VCR). The different vertebral osteotomies have unique merits and pitfalls that need to be addressed during preoperative planning to achieve maximum benefit while limiting or avoiding possible complications. The more difficult vertebral osteotomies have a steeper learning curve and requires extensive pre, intra and postoperative management of the patient. This review will aim to discuss the indications, surgical techniques, and clinical outcomes for each of these different vertebral osteotomy techniques with illustrative cases.

A new classification for coronal malalignment in adult spinal deformity: a validation and the role of lateral bending radiographs

PURPOSE

Coronal malalignment (CM) causes pain, impairment of function and cosmetic problems for adult spinal deformity (ASD) patients in addition to sagittal malalignment. Certain types of CM are at risk of insufficient re-alignment after correction. However, CM has received minimal attention in the literature compared to sagittal malalignment. The purpose was to establish reliability for our recently published classification system of CM in ASD among spine surgeons.

METHODS

Fifteen readers were assigned 28 cases for classification, who represented CM with reference to their full-length standing anteroposterior and lateral radiographs. The assignment was repeated 2 weeks later, then a third assignment was done with reference to additional side bending radiographs (SBRs). Intra-, inter-rater reliability and contribution of SBRs were determined.

RESULTS

Intra-rater reliability was calculated as 0.95, 0.86 and 0.73 for main curve types, subtypes with first modifier, and subtypes with two modifiers respectively. Inter-rater reliability averaged 0.91, 0.75 and 0.52. No differences in intra-rater reliability were shown between the four expert elaborators of the classification and other readers. SBRs helped to increase the concordance rate of second modifiers or changed to appropriate grading in cases graded type A in first modifier.

CONCLUSIONS

Adequate intra- and inter-rater reliability was shown in the Obeid-CM classification with reference to full spine anteroposterior and lateral radiographs. While side bending radiographs did not improve the classification reliability, they contributed to a better understanding in certain cases. Surgeons should consider both the sagittal and coronal planes, and this system may allow better surgical decision making for CM.

Ideal sagittal profile restoration and ideal lumbar apex positioning play an important role in postoperative mechanical complications after a lumbar PSO

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

To determine the influence of postoperative ideal lordosis distribution and ideal sagittal harmony on mechanical complications in patients undergoing one-level lumbar pedicle subtraction osteotomy (L-PSO). Many variables have been associated with mechanical complications after L-PSO. However, the impact of restoring the ideal inflexion point, lumbar apex, and sagittal shape is still underexplored.

METHODS

Analyzed risk factors were: age and patient-related variables, PSO level, interbody cages, rod material/diameter, number of rods, upper instrumented vertebra, lower instrumented vertebra, PI-LL mismatch, global tilt (GT), postoperative level of lumbar apex (LApex), postoperative level of inflexion point (InfxP), and postoperative type of Roussouly sagittal profile (R-type). These last variables were compared to ideal (based on pelvic incidence). Univariate and multivariate analyses were performed to identify risks for mechanical complications with a minimum 2-year follow-up.

RESULTS

A total of 87 patients were included. Mean follow-up was 4.5 ± 1.7 years. 40.2% of the patients suffered postoperative mechanical complications (7 PJK, 4 PJF, 18 pseudoarthrosis/rod breakage, 6 screw pullout). Mean time for complications was 584 ± 416 days from surgery. Univariate analysis showed that age (63 vs 57 years; P = 0.04), BMI (28.1 vs 25.9; P = 0.024), preoperative-GT (50.7° vs 38.7°; P < 0.001), postoperative-GT (28.9° vs 23.4°; P = 0.018), postoperative LApex location mismatched from ideal (77.8% vs 22.2%; P = 0.036), and postoperative R-type mismatched from ideal (67.6% vs 22.6%; P < 0.001) were significantly related to mechanical complications. The independent factors selected by multivariate analysis were: postoperative R-type mismatched from ideal OR 11.3 (95% CI   3.9-32.6; P < 0.001), age OR 1.05 (95% CI 1-1.1; P = 0.03), and LApex matching OR 0.5 (95% CI 0.27-0.97; P = 0.04). The further the LApex was from its ideal position, the higher the risk of mechanical complications (P = 0.036).

CONCLUSIONS

Over other multiple suspected risk factors, proper lumbar apex position and ideal sagittal shape restoration played an important role in postoperative mechanical complications after L-PSO.

LEVEL OF EVIDENCE

III.

Peking University Third Hospital score: a comprehensive system to predict intra-operative blood loss in radical nephrectomy and thrombectomy

BACKGROUND

Radical nephrectomy and thrombectomy is the standard surgical procedure for the treatment of renal cell carcinoma (RCC) with tumor thrombus (TT). But the estimation of intra-operative blood loss is only based on the surgeon's experience. Therefore, our study aimed to develop Peking University Third Hospital score (PKUTH score) for the prediction of intra-operative blood loss volume in radical nephrectomy and thrombectomy.

METHODS

The clinical data of 153 cases of renal mass with renal vein (RV) or inferior vena cava tumor thrombus admitted to Department of Urology, Peking University Third Hospital from January 2015 to May 2018 were retrospectively analyzed. The total amount of blood loss during operation is equal to the amount of blood sucked out by the aspirator plus the amount of blood in the blood-soaked gauze. Univariate linear analysis was used to analyze risk factors for intra-operative blood loss, then significant factors were included in subsequent multivariable linear regression analysis.

RESULTS

The final multivariable model included the following three factors: open operative approach (P < 0.001), Neves classification IV (P < 0.001), inferior vena cava resection (P = 0.001). The PKUTH score (0-3) was calculated according to the number of aforementioned risk factors. A significant increase of blood loss was noticed along with higher risk score. The estimated median blood loss from PKUTH score 0 to 3 was 280 mL (interquartile range [IQR] 100-600 mL), 1250 mL (IQR 575-2700 mL), 2000 mL (IQR 1250-2900 mL), and 5000 mL (IQR 4250-8000 mL), respectively. Meanwhile, the higher PKUTH score was, the more chance of post-operative complications (P = 0.004) occurred. A tendency but not significant overall survival difference was found between PKUTH risk score 0 vs. 1 to 3 (P = 0.098).

CONCLUSION

We present a structured and quantitative scoring system, PKUTH score, to predict intra-operative blood loss volume in radical nephrectomy and thrombectomy.

Ten techniques for improving navigated spinal surgery

With the identification of literature shortfalls on the techniques employed in intraoperative navigated (ION) spinal surgery, we outline a number of measures which have been synthesised into a coherent operative technique. These include positioning, dissection, management of the reference frame, the grip, the angle of attack, the drill, the template, the pedicle screw, the wire, and navigated intrathecal analgesia. Optimizing techniques to improve accuracy allow an overall reduction of the repetition of the surgical steps with its associated productivity benefits including time, cost, radiation, and safety.

Cite this article: Bone Joint J 2020;102-B(3):371–375.

The impact of surgeon experience on perioperative complications and operative measures following thoracolumbar 3-column osteotomy for adult spinal deformity: overcoming the learning curve

OBJECTIVE

Posterior-based thoracolumbar 3-column osteotomy (3CO) is a formidable surgical procedure. Surgeon experience and case volume are known factors that influence surgical complication rates, but these factors have not been studied well in cases of adult spinal deformity (ASD). This study examines how surgeon experience affects perioperative complications and operative measures following thoracolumbar 3CO in ASD.

METHODS

A retrospective study was performed of a consecutive cohort of thoracolumbar ASD patients who underwent 3CO performed by the senior authors from 2006 to 2018. Multivariate analysis was used to assess whether experience (years of experience and/or number of procedures) is associated with perioperative complications, operative duration, and blood loss.

RESULTS

A total of 362 patients underwent 66 vertebral column resections (VCRs) and 296 pedicle subtraction osteotomies (PSOs). The overall complication rate was 29.4%, and the surgical complication rate was 8.0%. The rate of postoperative neurological deficits was 6.2%. There was a trend toward lower overall complication rates with greater operative years of experience (from 44.4% to 28.0%) (p = 0.115). Years of operative experience was associated with a significantly lower rate of neurological deficits (p = 0.027); the incidence dropped from 22.2% to 4.0%. The mean operative time was 310.7 minutes overall. Both increased years of experience and higher case numbers were significantly associated with shorter operative times (p < 0.001 and p = 0.001, respectively). Only operative years of experience was independently associated with operative times (p < 0.001): 358.3 minutes from 2006 to 2008 to 275.5 minutes in 2018 (82.8 minutes shorter). Over time, there was less deviation and more consistency in operative times, despite the implementation of various interventions to promote fusion and prevent construct failure: utilization of multiple-rod constructs (standard, satellite, and nested rods), bone morphogenetic protein, vertebroplasty, and ligament augmentation. Of note, the use of tranexamic acid did not significantly lower blood loss.

CONCLUSIONS

Surgeon years of experience, rather than number of 3COs performed, was a significant factor in mitigating neurological complications and improving quality measures following thoracolumbar 3CO for ASD. The 3- to 5-year experience mark was when the senior surgeon overcame a learning curve and was able to minimize neurological complication rates. There was a continuous decrease in operative time as the surgeon's experience increased; this was in concurrence with the implementation of additional preventative surgical interventions. Ongoing practice changes should be implemented and can be done safely, but it is imperative to self-assess the risks and benefits of those practice changes.

The learning curve for performing three-column osteotomies in adult spinal deformity patients: one surgeon's experience with 197 cases

BACKGROUND CONTEXT

Three-column osteotomy (3CO) is used to correct rigid adult spinal deformity. It presents risk of complications because it involves extensive osseous resection and spinal destabilization.

PURPOSE

Our purpose was to characterize the learning curve for performing 3CO in adult spinal deformity patients.

DESIGN

Retrospective review.

PATIENT SAMPLE

A surgical registry at a tertiary care center was used to identify 238 cases of 3CO for correction of adult spinal deformity by 1 surgeon between 2005 and 2014. Patients with at least 1 year of clinical and radiographic follow-up were included (n=197; mean duration of follow-up, 43 months; range, 12-121).

OUTCOME MEASURES

We quantified associations between surgeon experience and (1) estimated blood loss per vertebral level fused (EBL/VLF), (2) incidence of new neurologic deficits, (3) incidence of reoperation for instrumentation failure, (4) operative time in minutes, and (5) magnitude of correction at the level of the osteotomy.

METHODS

The learning curve for binary outcomes was demonstrated using a LOWESS smoother plot of the probability of occurrence. Change in risk was calculated using a generalized linear model with link identity and binomial family. The learning curve for continuous variables was demonstrated using a scatter plot and a line of best fit based on linear regression analysis. Alpha=0.05.

RESULTS

EBL/VLF decreased by a mean of 19.7 mL (95% confidence interval [CI]: 11.3-28.1) with each 10 cases (decrease of 388 mL/level fused by the end of the study period). The risk of a neurologic deficit declined by 7.98% (95% CI: 7.98%, 7.99%) with every 100 cases. The risk of reoperation declined by 1.99% (95% CI: 0.83%, 3.17%) with every 10 cases until the 100th case. After that point, there was no significant change in the probability of reoperation (p>.05). The magnitude of correction and operative time did not change with increasing surgeon experience (p>.05).

CONCLUSION

Incidence of reoperation for instrumentation failure, incidence of new neurologic deficits, and estimated blood loss improved with increasing surgeon experience at performing 3CO. Most outcomes, except the risk of reoperation, improved through the last case.

Correction of adult spinal deformity with a minimally invasive fusionless bipolar construct: Preliminary results

INTRODUCTION

Fusion in adult spinal deformity has a high rate of complications. Fusionless constructs in children and percutaneous fixation in adults are now being used routinely. The aim of this study was to evaluate the preliminary results of a minimally invasive fusionless surgical technique used to correct adult spinal deformity.

MATERIALS AND METHODS

Thirty-eight patients with an average age of 45 years (15-76) with major spinal deformity requiring extensive arthrodesis from the upper thoracic region to the pelvis were operated consecutively and followed prospectively. Two hooks were implanted at the top and two iliosacral screws at the bottom. Two large rods connected by dominos to two small rods joined the upper hooks to the lower screws. The surgical data (operative time and bleeding), the radiological findings (Cobb angle, sagittal parameters, C7-plumbline AP and lateral), the complication rate and the morbidity were evaluated at the last follow-up visit.

RESULTS

The primary curvature was reduced by 40% from a mean of 58.5° (26-146) to 35.2° (3-109) (p<0.001). A clear decrease in operating time (270min) and blood loss (50cc/level) were observed. The length of hospitalization averaged 18 days (6-66), including an 8-15 day long preoperative traction period for 11 patients. We found 7 infectious complications, 11 early mechanical complications and one case of paraplegia due to severe kyphoscoliosis.

CONCLUSION

The corrections obtained are comparable to those reported in the literature for standard constructs. Most patients had an uneventful postoperative course. The early complications observed led us to very carefully select the indications. Long-term follow-up is essential.