Assessing the Reproducibility of the Structured Abstracts Generated by ChatGPT and Bard Compared to Human-Written Abstracts in the Field of Spine Surgery: Comparative Analysis.

BACKGROUND: Due to recent advances in artificial intelligence (AI), language model applications can generate logical text output that is difficult to distinguish from human writing. ChatGPT (OpenAI) and Bard (subsequently rebranded as "Gemini"; Google AI) were developed using distinct approaches, but little has been studied about the difference in their capability to generate the abstract. The use of AI to write scientific abstracts in the field of spine surgery is the center of much debate and controversy. OBJECTIVE: The objective of this study is to assess the reproducibility of the structured abstracts generated by ChatGPT and Bard compared to human-written abstracts in the field of spine surgery. METHODS: In total, 60 abstracts dealing with spine sections were randomly selected from 7 reputable journals and used as ChatGPT and Bard input statements to generate abstracts based on supplied paper titles. A total of 174 abstracts, divided into human-written abstracts, ChatGPT-generated abstracts, and Bard-generated abstracts, were evaluated for compliance with the structured format of journal guidelines and consistency of content. The likelihood of plagiarism and AI output was assessed using the iThenticate and ZeroGPT programs, respectively. A total of 8 reviewers in the spinal field evaluated 30 randomly extracted abstracts to determine whether they were produced by AI or human authors. RESULTS: The proportion of abstracts that met journal formatting guidelines was greater among ChatGPT abstracts (34/60, 56.6%) compared with those generated by Bard (6/54, 11.1%; P<.001). However, a higher proportion of Bard abstracts (49/54, 90.7%) had word counts that met journal guidelines compared with ChatGPT abstracts (30/60, 50%; P<.001). The similarity index was significantly lower among ChatGPT-generated abstracts (20.7%) compared with Bard-generated abstracts (32.1%; P<.001). The AI-detection program predicted that 21.7% (13/60) of the human group, 63.3% (38/60) of the ChatGPT group, and 87% (47/54) of the Bard group were possibly generated by AI, with an area under the curve value of 0.863 (P<.001). The mean detection rate by human reviewers was 53.8% (SD 11.2%), achieving a sensitivity of 56.3% and a specificity of 48.4%. A total of 56.3% (63/112) of the actual human-written abstracts and 55.9% (62/128) of AI-generated abstracts were recognized as human-written and AI-generated by human reviewers, respectively. CONCLUSIONS: Both ChatGPT and Bard can be used to help write abstracts, but most AI-generated abstracts are currently considered unethical due to high plagiarism and AI-detection rates. ChatGPT-generated abstracts appear to be superior to Bard-generated abstracts in meeting journal formatting guidelines. Because humans are unable to accurately distinguish abstracts written by humans from those produced by AI programs, it is crucial to exercise special caution and examine the ethical boundaries of using AI programs, including ChatGPT and Bard.

Comparative Analysis of Monoaxial and Polyaxial Pedicle Screws in the Surgical Correction of Adolescent Idiopathic Scoliosis.

Background: Although several biomechanical studies have been reported, few clinical studies have compared the efficacy of monoaxial and polyaxial pedicle screws in the surgical treatment of adolescent idiopathic scoliosis (AIS). This study aims to compare the radiological and clinical outcomes of mono- and polyaxial pedicle screws in the surgical treatment of AIS. Methods: A total of 46 AIS patients who underwent surgery to treat scoliosis using pedicle screw instrumentation (PSI) and rod derotation (RD) were divided into two groups according to the use of pedicle screws: the monoaxial group (n = 23) and polyaxial group (n = 23). Results: The correction rate of the main Cobb's angle was higher in the monoaxial group (70.2%) than in the polyaxial group (65.3%) (p = 0.040). No differences in the rotational correction of the apical vertebra were evident between the two groups. SRS-22 scores showed no significant differences according to the type of pedicle screws used. Conclusions: The use of polyaxial pedicle screws resulted in coronal, sagittal, and rotational correction outcomes comparable to those associated with the use of monoaxial pedicle screws for surgical treatment using PSI and RD to treat moderate cases of AIS.

Hidden Blood Loss and Its Risk Factors for Oblique Lumbar Interbody Fusion.

(1) Background: The amount of blood loss during oblique lumber interbody fusion (OLIF) surgery is often underestimated and may contribute to adverse postoperative outcomes. This study aims to evaluate hidden blood loss (HBL) in patients who underwent OLIF for degenerative lumbar spine disease and to analyze its risk factors. (2) Methods: The medical records of 179 patients who underwent OLIF surgery from 2015 to 2022 were reviewed. The HBL and total blood loss (TBL) were estimated using the Gross formula. Pearson correlation, Spearman correlation, and multivariate linear regression analyses were used to investigate risk factors for HBL. (3) Results: The mean HBL was 675.2 mL, and the mean hemoglobin loss was 1.7 g/dL during OLIF surgery. In the multivariate linear regression analysis, TBL (p < 0.001), estimated blood loss (p < 0.001), and pedicle screw fixation type (p = 0.039) were identified as independent risk factors of HBL. (4) Conclusions: The OLIF is associated with substantial perioperative HBL, for which we identified risk factors of TBL, EBL, and pedicle screw fixation type. Notably, OLIF with percutaneous pedicle screw fixation resulted in greater HBL than stand-alone OLIF or OLIF with open pedicle screw fixation.

Fusion Length Requiring Spinopelvic Fixation in Lumbosacral Fusion with Anterior Column Support at L5-S1: Assessment of Fusion Status Using Computed Tomography.

Background: The lumbosacral (LS) junction has a higher nonunion rate than other lumbar segments, especially in long-level fusion. Nonunion at L5-S1 would result in low back pain, spinal imbalance, and poor surgical outcomes. Although anterior column support at L5-S1 has been recommended to prevent nonunion in long-level LS fusion, fusion length requiring additional spinopelvic fixation (SPF) in LS fusion with anterior column support at L5-S1 has not been evaluated thoroughly. This study aimed to determine the number of fused levels requiring SPF in LS fusion with anterior column support at L5-S1 by assessing the interbody fusion status using computed tomography (CT) depending on the fusion length. Methods: Patients who underwent instrumented LS fusion with L5-S1 interbody fusion without additional augmentation and CT > 1 year postoperatively were included. The fusion rates were assessed based on the number of fused segments. Patients were divided into two groups depending on the L5-S1 interbody fusion status: those with union vs. those with nonunion. Binary logistic regression analyses were performed to identify risk factors for LS junctional nonunion. Results: Fusion rates of L5-S1 interbody fusion were 94.9%, 90.3%, 80.0%, 50.0%, 52.6%, and 43.5% for fusion of 1, 2, 3, 4, 5, and ≥ 6 levels, respectively. The number of spinal levels fused ≥ 4 (p < 0.001), low preoperative bone mineral density (BMD; adjusted odds ratio [aOR], 0.667; p = 0.035), and postoperative pelvic incidence (PI) - lumbar lordosis (LL) mismatch (aOR, 1.034; p = 0.040) were identified as significant risk factors for nonunion of L5-S1 interbody fusion according to the multivariate logistic regression analysis. Conclusions: Exhibiting ≥ 4 fused spinal levels, low preoperative BMD, and large postoperative PI-LL mismatch were identified as independent risk factors for nonunion of anterior column support at L5-S1 in LS fusion without additional fixation. Therefore, SPF should be considered in LS fusion extending to or above L2 to prevent LS junctional nonunion.

Long-term Outcomes of Posterior Multilevel Crack Osteotomy: Revisional Surgery for Scoliosis With a Fusion Mass.

OBJECTIVE: Osteotomies are required for the mobilization of spinal segments in patients with revisional scoliosis surgery with a fusion mass; however, only a few techniques have shown efficacy and safety, and their mid- and long-term outcomes remain unelucidated. This study aimed to analyze long-term outcomes of the posterior multilevel crack osteotomy (PMCO) technique for revisional surgery for scoliosis with a fusion mass. METHODS: Data from 18 patients who underwent revisional scoliosis surgery using PMCO between 2009 and 2015 and had more than 5-year follow-up were retrospectively reviewed. The Cobb angle and coronal and sagittal balance parameters were examined preoperatively, postoperatively, and during the final follow-up. Perioperative parameters and complications were also assessed. RESULTS: Preoperative and postoperative Cobb angles were 60.5° and 29.9°, respectively (p < 0.001); this improvement was maintained until the final follow-up (33.4°, p = 0.058). The difference in preoperative and postoperative coronal balance was statistically significant (15.9 mm and 9.2 mm, respectively; p < 0.001); this was maintained until the final follow-up (p = 0.071). There was no change in sagittal balance parameters over the 3 measurement periods. Only 1 patient showed PMCO-related motor weakness, but he spontaneously recovered 3 months after postsurgery. Pseudarthrosis was not observed during the follow-up period. CONCLUSION: Incomplete osteotomy using PMCO provided satisfactory deformity correction without severe complications during revisional surgery for scoliosis with a fusion mass. It may be a less invasive procedure that maintains cortical continuity, preserves soft tissues, and provides sufficient mobility for the correction of spinal segments.

Safe Optimal Tear Drop View for Spinopelvic Fixation Using a Three-Dimensional Reconstruction Model of the Pelvis.

Background: Spinopelvic fixation (SPF) has been a challenge for surgeons despite the advancements in instruments and surgical techniques. C-arm fluoroscopy-guided SPF is a widely used safe technique that utilizes the tear drop view. The tear drop view is an image of the corridor from the posterior superior iliac spine to the anterior inferior iliac spine (AIIS) of the pelvis. This study aimed to define the safe optimal tear drop view using three-dimensional reconstruction of computed tomography images. Methods: Three-dimensional reconstructions of the pelvises of 20 individuals were carried out. By rotating the reconstructed model, we simulated SPF with a cylinder representing imaginary screw. The safe optimal tear drop view was defined as the one embracing a corridor with the largest diameter with the inferior tear drop line not below the acetabular line and the lateral tear drop line medial to the AIIS. The distance between the lateral border of the tear drop and AIIS was defined as tear drop index (TDI) to estimate the degree of rotation on the plane image. Tear drop ratio (TDR), the ratio of the distance between the tear drop center and the AIIS to TDI, was also devised for more intuitive application of our simulation in a real operation. Results: All the maximum diameters and lengths were greater than 9 mm and 80 mm, respectively, which are the values of generally used screws for SPF at a TDI of 5 mm and 10 mm in both sexes. The TDRs were 3.40 ± 0.41 and 3.35 ± 0.26 in men and women, respectively, at a TDI of 5 mm. The TDRs were 2.26 ± 0.17 and 2.14 ± 0.12 in men and women, respectively, at a TDI of 10 mm. Conclusions: The safe optimal tear drop view can be obtained with a TDR of 2.5 to 3 by rounding off the measured values for intuitive application in the actual surgical field.

The Accuracy and Safety of a Pedicle Screw Using the Freehand Technique in Minimally Invasive Scoliosis Surgery.

OBJECTIVE: The safety and clinical usefulness of minimally invasive scoliosis surgery (MISS) has been reported in various studies. However, freehand pedicle screwing in MISS remains technically challenging. The purpose of this study is to evaluate the accuracy and safety of pedicle screw placement using the freehand technique in adolescent idiopathic scoliosis (AIS) patients treated with MISS compared to conventional open scoliosis surgery (COSS). METHODS: We included 76 patients who underwent deformity correction for AIS. Computed tomography scans were used to assess screw violations divided into 2 groups according to the surgical technique: MISS or COSS. Anterior violations were classified into grade 0, 1 (no contact with internal organs), and 2 (contact with internal organs). Medial and lateral violations were classified into grade 0, 1 ( < 2 mm), and 3 ( ≥ 2 mm). grade 2 were considered critical violations. RESULTS: A total of 630 and 1,174 pedicle screws were inserted in the MISS and COSS groups, respectively. The overall critical violation rates of the MISS and COSS groups were 16.8% (106 screws) and 14.0% (165 screws) (p = 0.116). Medial critical violations on the left side in the middle thoracic region frequently occurred in the MISS group compared to the COSS group (p = 0.003). There were no statistical differences in the complications. CONCLUSION: Pedicle screw placement using the freehand technique in MISS for AIS patients provided similar accuracy and safety compared to COSS. Pedicle screws inserted on the left side of the middle thoracic region, exhibited more medial critical violations in the MISS group.

Learning Curve for Minimally Invasive Scoliosis Surgery in Adolescent Idiopathic Scoliosis.

OBJECTIVE: To evaluate the learning curve of minimally invasive scoliosis surgery (MISS) in patients with adolescent idiopathic scoliosis (AIS). METHODS: A total of 76 AIS patients who underwent MISS were included from March 2015 to February 2017. The cases were divided chronologically into early period group (Group A, March 2015-February 2016, n = 31) and late period group (Group B, March 2016-February 2017, n = 45). Radiological parameters, operative parameters, and clinical outcomes were included in this study. The selected criteria for receiver operating characteristic analysis used to assess learning curve were mean operative time (≤389 minutes) and estimated blood loss (EBL) (≤948 mL). RESULTS: The mean operative time was 389 minutes, and the EBL was 948 mL. The mean operative time was significantly reduced in the late period group (360 minutes) compared to the early period group (431 minutes) (P < 0.005). The mean EBL was significantly reduced for the late period group (798 mL) compared to the early period group (1164 mL) (P < 0.001). Forty-six cases were required to achieve the preset criteria (area under the curve 0.858; P < 0.001; sensitivity 0.778; specificity 0.796). CONCLUSIONS: A mild learning curve was demonstrated in MISS for AIS with significant improvement in operative times and EBL over time. Experience of more than 46 cases of MISS was required to obtain proficient surgical skills for a trained surgeon of conventional open scoliosis surgery.

Fusion rates based on type of bone graft substitute using minimally invasive scoliosis surgery for adolescent idiopathic scoliosis.

BACKGROUND: Minimally invasive scoliosis surgery (MISS) is currently introduced on novel technique for surgical treatment of adolescent idiopathic scoliosis (AIS). This study is aimed to evaluate the efficacy of facet fusion in MISS compared to posterior fusion in conventional open scoliosis surgery (COSS) and compare facet fusion rates based on three bone graft substitutes in MISS for adolescent idiopathic scoliosis (AIS). METHODS: Eighty six AIS patients who underwent scoliosis surgery were divided into two groups: the COSS group and the MISS group. COSS was performed through posterior fusion with allograft. MISS was applied via facet fusion with three bone graft substitutes. The MISS group was further divided into three subgroups based on graft substitute: Group A (allograft), Group B (demineralized bone matrix [DBM]), and group C (demineralized cancellous bone chips). Fusion rate was measured using conventional radiographs to visualize loss of correction > 10°, presence of lysis around implants, breaks in fusion mass, and abnormal mobility of the fused segment. RESULTS: The fusion rates showed no significant difference in COSS and MISS groups (p = 0.070). In the MISS group, the fusion rates were 85, 100, and 100% in groups A, B, and C, respectively, with no significant difference (p = 0.221). There were no statistical differences between groups A, B, and C in terms of correction rate, fusion rate, and SRS-22 scores (p > 0.05). CONCLUSIONS: The facet fusion in MISS showed comparable to posterior fusion in COSS with regard to radiological and clinical outcomes. Furthermore, the type of graft substitute among allograft, DBM, and demineralized cancellous bone chips did not affect facet fusion rate or clinical outcomes in MISS. Therefore, MISS showed comparable fusion rate (with no influences on the type of graft substitute) and clinical outcomes to those of COSS in the surgical treatment of AIS.

Adult Spinal Deformity: A Comprehensive Review of Current Advances and Future Directions.

Owing to rapidly changing global demographics, adult spinal deformity (ASD) now accounts for a significant proportion of the Global Burden of Disease. Sagittal imbalance caused by age-related degenerative changes leads to back pain, neurological deficits, and deformity, which negatively affect the health-related quality of life (HRQoL) of patients. Along with the recognized regional, global, and sagittal spinopelvic parameters, poor paraspinal muscle quality has recently been acknowledged as a key determinant of the clinical outcomes of ASD. Although the Scoliosis Research Society-Schwab ASD classification system incorporates the radiological factors related to HRQoL, it cannot accurately predict the mechanical complications. With the rapid advances in surgical techniques, many surgical options for ASD have been developed, ranging from minimally invasive surgery to osteotomies. Therefore, structured patient-specific management is important in surgical decision-making, selecting the proper surgical technique, and to prevent serious complications in patients with ASD. Moreover, utilizing the latest technologies such as robotic-assisted surgery and machine learning, should help in minimizing the surgical risks and complications in the future.

Novel Surgical Technique for Adolescent Idiopathic Scoliosis: Minimally Invasive Scoliosis Surgery.

Despite advancements in instruments and surgical techniques for adolescent idiopathic scoliosis (AIS) surgery, conventional open scoliosis surgery (COSS) is usually required to achieve satisfactory deformity correction using various distinct surgical techniques, such as rod derotation, direct vertebral rotation, facetectomies, osteotomies, and decortication of the laminae. However, COSS is accompanied by significant blood loss and requires a large midline skin incision. Minimally invasive surgery (MIS) has evolved enormously in various fields of spinal surgery, including degenerative spinal diseases. MIS of the spine has some advantages over conventional surgery, such as a smaller incision, less blood loss and postoperative pain, and lower infection rates. Since the introduction of MIS for AIS in 2011, MIS has been reported to have comparable outcomes, including correction rate with some usual advantages of MIS. However, several complications, such as dislodgement of rods, wound infection, and hypertrophic scar formation, have also been reported in the initial stages of MIS for AIS. We devised a novel approach, called the coin-hole technique or minimally invasive scoliosis surgery (MISS), to minimize these complications. This article aimed to introduce a novel surgical technique for AIS and provide a preliminary analysis and up-to-date information regarding MISS.

Proximal Junctional Kyphosis in Adult Spinal Deformity: Definition, Classification, Risk Factors, and Prevention Strategies.

Proximal junctional problems are among the potential complications of surgery for adult spinal deformity (ASD) and are associated with higher morbidity and increased rates of revision surgery. The diverse manifestations of proximal junctional problems range from proximal junctional kyphosis (PJK) to proximal junctional failure (PJF). Although there is no universally accepted definition for PJK, the most common is a proximal junctional angle greater than 10° that is at least 10° greater than the preoperative measurement. PJF represents a progression from PJK and is characterized by pain, gait disturbances, and neurological deficits. The risk factors for PJK can be classified according to patient-related, radiological, and surgical factors. Based on an understanding of the modifiable factors that contribute to reducing the risk of PJK, prevention strategies are critical for patients with ASD.

Long-Term Influence of Paraspinal Muscle Quantity in Adolescent Idiopathic Scoliosis Following Deformity Correction by Posterior Approach.

Pedicle screw instrumentation (PSI) through posterior approach has been the mainstay of deformity correction for adolescent idiopathic scoliosis (AIS). However, changes in the quantity of paraspinal muscles after AIS surgery has remained largely unknown. The aim of this study was to investigate long-term follow-up changes in paraspinal muscle volume in AIS surgery via a posterior approach. Forty-two AIS patients who underwent deformity correction by posterior approach were analyzed through a longitudinal assessment of a cross-sectional area (CSA) in paraspinal muscles with a minimum five-year follow-up. The CSA were measured using axial computed tomography images at the level of the upper endplate L4 by manual tracing. The last follow-up CSA ratio of the psoas major muscle (124.5%) was significantly increased compared to the preoperative CSA ratio (122.0%) (p < 0.005). The last follow-up CSA ratio of the multifidus and erector spine muscles significantly decreased compared to the preoperative CSA ratio (all p < 0.005). The CSA ratio of the erector spine muscle was correlated with the CSA ratio of the psoas major (correlation coefficient = 0.546, p < 0.001). Therefore, minimizing the injury to the erector spine muscle is imperative to maintaining psoas major muscle development in AIS surgery by posterior approach.

Risk of reoperation and infection after percutaneous endoscopic lumbar discectomy and open lumbar discectomy : a nationwide population-based study.

AIMS: Open discectomy (OD) is the standard operation for lumbar disc herniation (LDH). Percutaneous endoscopic lumbar discectomy (PELD), however, has shown similar outcomes to OD and there is increasing interest in this procedure. However despite improved surgical techniques and instrumentation, reoperation and infection rates continue and are reported to be between 6% and 24% and 0.7% and 16%, respectively. The objective of this study was to compare the rate of reoperation and infection within six months of patients being treated for LDH either by OD or PELD. METHODS: In this retrospective, nationwide cohort study, the Korean National Health Insurance database from 1 January 2007 to 31 December 2018 was reviewed. Data were extracted for patients who underwent OD or PELD for LDH without a history of having undergone either procedure during the preceding year. Individual patients were followed for six months through their encrypted unique resident registration number. The primary endpoints were rates of reoperation and infection during the follow-up period. Other risk factors for reoperation and infection were also evalulated. RESULTS: Out of 549,531 patients, 522,640 had undergone OD (95.11%) and 26,891 patients had undergone PELD (4.89%). Reoperation rates within six months were 2.28% in the OD group, and 5.38% in the PELD group. Infection rates were 1.18% in OD group and 0.83% in PELD group. The risk of reoperation was lower for patients with OD than for patients with PELD (adjusted hazard ratio (HR) 0.38). The risk of infection was higher for patients with OD than for patients undergoing PELD (HR, 1.325). CONCLUSION: Compared with the OD group, the PELD group showed higher reoperation rates and lower infection rates. Cite this article: Bone Joint J 2021;103-B(8):1392-1399.

Minimally invasive scoliosis surgery for adolescent idiopathic scoliosis using posterior mini-open technique.

The purpose of this study aimed to analyze and evaluate the radiologic and clinical outcomes of minimally invasive scoliosis surgery (MISS) for correcting adolescent idiopathic scoliosis (AIS) using the mini-open technique. Thirty-four AIS patients who underwent MISS using the mini-open technique for deformity correction. Using two to four 3-centimeter-long skin incisions (mini-open) and tubular retractors, we performed screw fixations, rod assembly, rod derotation maneuver (RD), and bone graft. For thoracoplasty, four to six ribs were resected using the same incisions. Correction was attempted using rod translation and RD maneuvers. Radiological outcomes and clinical outcomes (SRS-22) were evaluated. Mean preoperative Cobb's angle was 61.3° and curve flexibility (major curve) was 26.1%. This angle was corrected to 21.6° with a correction rate of 65.2% (P < 0.001). The coronal balance was not changed significantly. Sagittal vertical axes were corrected from -3.5 mm to 8.6 mm (-22 to 36.3 mm) (P = 0.009). Thoracic kyphosis angles and lumbar lordosis angles were not changed significantly but the values were within normal range. Each score of self-image in the SRS-22 questionnaire as well as the total score were improved significantly (P < 0.001). In conclusion, the MISS for correcting AIS using the mini-open technique showed comparable radiologic and clinical outcomes with fewer complications in patients with non-rigid scoliosis with Cobb's angle between 50° and 80°. Long-term results of this novel MISS using the mini-open technique could further strengthen the rationale for adopting this technique for curve correction in selected cases of AIS.

Comparative Analysis of Radiologic and Clinical Outcomes Between Conventional Open and Minimally Invasive Scoliosis Surgery for Adolescent Idiopathic Scoliosis.

OBJECTIVE: To compare radiologic and clinical outcomes between conventional open scoliosis surgery (COSS) and minimally invasive scoliosis surgery (MISS) for adolescent idiopathic scoliosis (AIS). METHODS: Forty-nine AIS patients who underwent scoliosis surgery were retrospectively analyzed in 2 groups: the COSS (n = 25) and MISS (n = 24) groups. COSS procedures used monoaxial screws with a rod derotation (RD) maneuver through a long linear incision. In the MISS group, the technique was applied via 2 or 3 incisions of about 3 cm in length, and a muscle-splitting approach and correction were performed using polyaxial screws with an RD maneuver. RESULTS: In the analysis of the coronal (Cobb angle of the main curve) and sagittal planes (thoracic kyphosis and lumbar lordosis), correction was significantly superior in the COSS group (all P values >0.05). However, in the coronal balance and spinal vertical axis, which are global balance factors, there were no significant differences between the groups (P = 0.331 and P = 0.750). There were significant differences between the COSS and MISS groups in terms of mean hospital stay duration (P < 0.001), operative time (P < 0.001), estimated blood loss (P < 0.001), and scar length (P < 0.001). There was no significant difference in the various Scoliosis Research Society-22 questionnaire scores between the groups. CONCLUSIONS: Although COSS for AIS was superior for correcting the main curve, MISS was associated with shorter hospitalization, less blood loss, and superior cosmesis as well as providing adequate correction in both the coronal and sagittal planes.

Predicting postoperative complications in patients undergoing lumbar spinal fusion by using the modified five-item frailty index and nutritional status.

AIMS: As the population ages and the surgical complexity of lumbar spinal surgery increases, the preoperative stratification of risk becomes increasingly important. Understanding the risks is an important factor in decision-making and optimizing the preoperative condition of the patient. Our aim was to determine whether the modified five-item frailty index (mFI-5) and nutritional parameters could be used to predict postoperative complications in patients undergoing simple or complex lumbar spinal fusion. METHODS: We retrospectively reviewed 584 patients who had undergone lumbar spinal fusion for degenerative lumbar spinal disease. The 'simple' group (SG) consisted of patients who had undergone one- or two-level posterior lumbar fusion. The 'complex' group (CG) consisted of patients who had undergone fusion over three or more levels, or combined anterior and posterior surgery. On admission, the mFI-5 was calculated and nutritional parameters collected. RESULTS: Complications occurred in 9.3% (37/396) of patients in the SG, and 10.1% (19/167) of patients in the CG. In the SG, the important predictors of complications were age (odds ratio (OR) 1.036; p = 0.002); mFI-5 (OR 1.026 to 2.411, as score increased to 1 ≥ 2 respectively; p = 0.023); albumin (OR 11.348; p < 0.001); vitamin D (OR 2.185; p = 0.032); and total lymphocyte count (OR 1.433; p = 0.011) . In the CG, the predictors of complications were albumin (OR 9.532; p = 0.002) and vitamin D (OR 3.815; p = 0.022). CONCLUSION: The mFI-5 and nutritional status were effective predictors of postoperative complications in the SG, but only nutritional status was successful in predicting postoperative complications in the CG. The complexity of the surgery, as well as the preoperative frailty and nutritional status of patients, should be considered when determining if it is safe to proceed with lumbar spinal fusion. Cite this article: Bone Joint J 2020;102-B(12):1717-1722.

Assessing changes in cervical epidural pressure during biportal endoscopic lumbar discectomy.

OBJECTIVE: Biportal endoscopic spinal surgery has been performed for several years, and its effectiveness is well known; however, no studies on its safety, specifically intracranial pressure, have been conducted to date. The authors sought to evaluate the effect of biportal endoscopic lumbar discectomy on intracranial pressure by monitoring cervical epidural pressure (CEP) changes throughout the procedure. METHODS: Twenty patients undergoing single-level biportal endoscopic lumbar discectomy were enrolled in this study. CEPs were monitored throughout the procedure, consisting of phase 1, establishing the surgical portal and working space; phase 2, performing decompression and discectomy; and phase 3, turning off the fluid irrigation system. After discectomy was completed, the authors evaluated changes in CEP as the irrigation pressure increased serially by adding phase 4, increasing irrigation pressure with outflow open; and phase 5, increasing irrigation pressure with outflow closed. RESULTS: The mean baseline CEP was measured as 16.65 mm Hg. In phase 1, the mean CEP was 17.3 mm Hg, which was not significantly different from the baseline CEP. In phase 2, the mean CEP abruptly increased up to 35.1 mm Hg when the epidural space was first connected with the working space, followed by stabilization of the CEP at 31.65 mm Hg. In phase 4, the CEP increased as the inflow pressure increased, showing a linear correlation, but not in phase 5. No patients experienced neurological complications. CONCLUSIONS: It is important to ensure that irrigation fluid is not stagnant and is maintained continuously. More attention must be paid to keeping pressures low when opening the epidural space.

Clinical and radiological outcomes of hemivertebra resection for congenital scoliosis in children under age 10 years: More than 5-year follow-up.

The surgical treatment of congenital scoliosis under 10 years is difficult as it involves resecting vertebrae. Moreover, patient follow-up after surgery is extremely important because the patient is a child whose growth has not been completed. However, there are very few long-term follow-up studies after surgical treatment of congenital scoliosis. Therefore, this study is designed to evaluate surgical outcomes after posterior hemivertebra resection in children under 10 years and its long-term effects.Twenty-one patients with congenital scoliosis who were younger than 10 years at the time of the surgery and received posterior hemivertebra resection and fusion using pedicle screw fixation were included in this study.There were significant improvements in the main curve, coronal balance, sagittal vertical axis, thoracic kyphosis, and lumbar lordosis after surgery (P < .001, .021, .047, .043, .006, respectively). Coronal balance, sagittal vertical axis, thoracic kyphosis, and lumbar lordosis remained within the normal range during the follow-up period; however, main curve deteriorated significantly (P = .005). Trunk appearance of perception scale improved significantly after surgery (P = .031) and was maintained during the follow-up period (P = .078).In conclusion, posterior hemivertebra resection and fusion using pedicle screw fixation in patients under 10 years old with congenital scoliosis is a safe and effective procedure that can achieve rigid fixation and deformity correction. Complete resection of the hemivertebra is important for deformity correction and prevention of curve progression, and careful long-term follow-up is necessary.