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

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

Predictors for hemostatic thrombin-gelatin matrix usage in spine surgery: a multicenter observational study.

STUDY DESIGN: A prospective cohort study. OBJECTIVES: Thrombin-gelatin matrix (TGM) is a rapid and potent hemostatic agent, but it has some limitations, including the cost and its preparation time. The purpose of this study was to investigate the current trend in the use of TGM and to identify the predictors for TGM usage in order to ensure its proper use and optimized resource allocation. METHODS: A total of 5520 patients who underwent spine surgery in a multicenter study group within a year were included in the study. The demographic factors and the surgical factors including spinal levels operated, emergency surgery, reoperation, approach, durotomy, instrumented fixation, interbody fusion, osteotomy, and microendoscopy-assistance were investigated. TGM usage and whether it was routine or unplanned use for uncontrolled bleeding were also checked. A multivariate logistic regression analysis was used to identify predictors for unplanned use of TGM. RESULTS: Intraoperative TGM was used in 1934 cases (35.0%), among which 714 were unplanned (12.9%). Predictors of unplanned TGM use were female gender (adjusted odds ratio [OR]: 1.21, 95% confidence interval [CI]: 1.02-1.43, p = 0.03), ASA grade ≥ 2 (OR: 1.34, 95% CI: 1.04-1.72, p = 0.02), cervical spine (OR: 1.55, 95% CI: 1.24-1.94, p < 0.001), tumor (OR: 2.02, 95% CI: 1.34-3.03, p < 0.001), posterior approach (OR: 1.66, 95% CI: 1.26-2.18, p < 0.001), durotomy (OR: 1.65, 95% CI: 1.24-2.20, p < 0.001), instrumentation (OR: 1.30, 1.03-1.63, p = 0.02), osteotomy (OR: 5.00, 2.76-9.05, p < 0.001), and microendoscopy (OR: 2.24, 1.84-2.73, p < 0.001). CONCLUSIONS: Many of the predictors for unplanned TGM use have been previously reported as risk factors for intraoperative massive hemorrhaging and blood transfusion. However, other newly revealed factors can be predictors of bleeding that is technically challenging to control. While routine usage of TGM in these cases will require further justification, these novel findings are valuable for implementing preoperative precautions and optimizing resource allocation.

Limitations of minimally invasive posterior cervical foraminotomy-a decompression method of posteriorly shifting the nerve root-in cases of large anterior osteophytes in cervical radiculopathy: A retrospective multicenter cohort study.

BACKGROUND: Posterior cervical foraminotomy against anterior osteophyte is an indirect decompression procedure but less invasive compared to anterior cervical discectomy and fusion. Residual compression to the nerve root may lead to poor surgical outcomes. Although clinical results of posterior cervical foraminotomy for osteophytes are not considered better than those of disk herniation, osteophyte size and the association of the decompression area with poor surgical outcomes remain unclear. This study aimed to identify the limitations of minimally invasive posterior cervical foraminotomy for cervical radiculopathy and discuss the methods to improve surgical outcomes. METHODS: We analyzed 55 consecutive patients with degenerative cervical radiculopathy who underwent minimally invasive posterior cervical foraminotomy. Minimum postoperative follow-up duration was 1 year. We divided the patients into nonimproved and improved groups. The cutoff value between preoperative and postoperative Neck Disability Index scores was 30% improvement. Preoperative imaging data comprised disk height, local kyphosis, spinal cord compression, anterior osteophytes in the foramen, and anterior osteophytes of >50% of the intervertebral foramen diameter. Postoperative imaging data comprised craniocaudal length and lateral width of decompressed lamina, preserved superior facet width, and area of decompressed lamina. RESULTS: Fifty-five patients were divided into two groups: nonimproved (n = 19) and improved (n = 36). The presence of osteophytes itself was not significant; however, the presence of osteophytes of >50% of the foramen diameter increased in the nonimproved group (P = 0.004). Mean lateral width and mean area of decompressed lamina after surgery significantly increased in the improved group (P = 0.001, P = 0.03). CONCLUSION: The presence of anterior osteophytes >50% of the diameter of the foramen led to poor improvement of clinical outcomes in minimally invasive posterior cervical foraminotomy. However, the larger the lateral width and area of the decompressed lamina, the better the surgical outcome.

Postoperative outcomes after degenerative lumbar spine surgery in rheumatoid arthritis patients -a propensity score-matched analysis.

BACKGROUND: Although treatment options for rheumatoid arthritis (RA) have evolved significantly since the introduction of biologic agents, degenerative lumbar disease in RA patients remains a major challenge. Well-controlled comparisons between RA patients and their non-RA counterparts have not yet been reported. The objective of the present study was to compare postoperative outcomes of lumbar spine surgery between RA and non-RA patients by a retrospective propensity score-matched analysis. METHODS: Patients who underwent primary posterior spine surgery for degenerative lumbar disease in our prospective multicenter study group between 2017 and 2020 were enrolled. Demographic data including age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) physical status classification, diabetes mellitus, smoking, steroid usage, number of spinal levels involved, and preoperative patient-reported outcome (PRO) scores (numerical rating scale [NRS] for back pain and leg pain, Short Form-12 physical component summary [PCS], EuroQOL 5-dimension [EQ-5D], and Oswestry Disability Index [ODI]) were used to calculate a propensity score for RA diagnosis. One-to-one matching was performed and 1-year postoperative outcomes were compared between groups. RESULTS: Among the 4567 patients included, 90 had RA (2.0%). RA patients in our cohort were more likely to be female, with lower BMI, higher ASA grade and lower current smoking rate than non-RA patients. Preoperative NRS scores for leg pain, PCS, EQ-5D, and ODI were worse in RA patients. Propensity score matching generated 61 pairs of RA and non-RA patients who underwent posterior lumbar surgery. After background adjustment, RA patients reported worse postoperative PCS (28.4 vs. 37.2, p = 0.008) and EQ-5D (0.640 vs. 0.738, p = 0.03), although these differences were not significant between RA and non-RA patients not on steroids. CONCLUSIONS: RA patients showed worse postoperative quality of life outcomes after posterior surgery for degenerative lumbar disease, while steroid-independent RA cases showed equivalent outcomes to non-RA patients.

Clinical Evaluation of Microendoscopy-Assisted Oblique Lateral Interbody Fusion.

Background and objectives: Oblique Lateral Interbody Fusion (OLIF) is a widely performed, minimally invasive technique to achieve lumbar lateral interbody fusion. However, some complications can arise due to constraints posed by the limited surgical space and visual field. The purpose of this study was to assess the short-term postoperative clinical outcomes of microendoscopy-assisted OLIF (ME-OLIF) compared to conventional OLIF. Materials and Methods: We retrospectively investigated 75 consecutive patients who underwent OLIF or ME-OLIF. The age, sex, diagnosis, and number of fused levels were obtained from medical records. Operation time, estimated blood loss (EBL), and intraoperative complications were also collected. Operation time and EBL were only measured per level required for the lateral procedure, excluding the posterior fixation surgery. The primary outcome measure was assessed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The secondary outcome measure was assessed using the Oswestry Disability Index (ODI) and the European Quality of Life-5 Dimensions (EQ-5D), measured preoperatively and 1-year postoperatively. Results: This case series consisted of 14 patients in the OLIF group and 61 patients in the ME-OLIF group. There was no significant difference between the two groups in terms of the mean operative time and EBL (p = 0.90 and p = 0.50, respectively). The perioperative complication rate was 21.4% in the OLIF group and 21.3% in the ME-OLIF group (p = 0.99). In both groups, the postoperative JOABPEQ, EQ-5D, and ODI scores improved significantly (p < 0.001). Conclusions: Although there was no significant difference in clinical results between the two surgical methods, the results suggest that both are safe surgical methods and that microendoscopy-assisted OLIF could serve as a potential alternative to the conventional OLIF procedure.

Partial Resection of Spinous Process for the Elderly Patients with Thoraco-Lumbar Kyphosis: Technical Report.

Background and objectives: Global sagittal imbalance with lumbar hypo-lordosis can cause low back pain (LBP) during standing and/or walking. This condition has recently been well-known as one of the major causes of reduced health-related quality of life (HRQOL) in elderly populations. Decrease in disc space of anterior elements and an increase in the spinous process height of posterior elements may both contribute to the decrease in lordosis of the lumbar spine. To correct the sagittal imbalance, the mainstream option is still a highly invasive surgery, such as long-segment fusion with posterior wedge osteotomy. Therefore, we developed a treatment that is partial resection of several spinous processes of thoraco-lumbar spine (PRSP) and lumbar extension exercise to improve the flexibility of the spine as postoperative rehabilitation. Materials and Methods: Consecutively, seven patients with over 60 mm of sagittal vertical axis (SVA) underwent PRSP. The operation was performed with several small midline skin incisions under general anesthesia. After splitting the supraspinous ligaments, the cranial or caudal tip of the spinous process of several thoraco-lumbar spines was removed, and postoperative rehabilitation was followed to improve extension flexibility. Results: The average follow-up period was 13.0 months. The average blood loss and operation time were 11.4 mL and 47.4 min, respectively. The mean SVA improved from 119 to 93 mm but deteriorated in one case. The mean numerical rating scale of low back pain improved from 6.6 to 3.7 without any exacerbations. The mean Oswestry Disability Index score was improved from 32.4% to 19.1% in six cases, with one worsened case. Conclusions: We performed PRSP and lumbar extension exercise for the patients with LBP due to lumbar kyphosis. This minimally invasive treatment was considered to be effective in improving the symptoms of low back pain and HRQOL, especially of elderly patients with lumbar kyphosis.

Correlation and differences in cervical sagittal alignment parameters between cervical radiographs and magnetic resonance images.

PURPOSE: Although cervical alignment is better assessed using standing radiography than supine magnetic resonance imaging (MRI), few studies have investigated this. This study aimed to investigate the difference in alignment between standing radiographs and supine MRI images, and assess whether neck position affects the cervical parameters and neurological changes. METHODS: We analyzed 53 patients, measuring the O-C2 angle, C2-7 angle (the distinction between the lordotic and kyphotic groups), T1 slope, neck tilt, thoracic inlet angle, and the C2-7 sagittal vertical axis. Inter- and intra-group analyses were conducted to identify any difference between standing radiography and supine MRI. Statistical differences between the cervical parameters were compared. RESULTS: Strong correlations were noted between the equivalent parameters in the radiographs and MRI images, whereas no significant difference was observed in C2-7 angle in the kyphotic group between the radiographs and MRI images, or for neck tilt between the radiographs and MRI images. However, in the lordotic group, the C2-7 angle was significantly different between the two types of images and larger in the radiographs than in the MRI images (C2-7 angle in the radiographs: C2-7 angle in the MRI images: 4.49°, p < 0.001). CONCLUSIONS: Neck tilt was a constant parameter. The C2-7 angle in the kyphotic group was similar between the standing radiographs and the supine MRI images; however, the C2-7 angle in the lordotic group was different. Therefore, we recommend that standing cervical radiographs should be preoperatively obtained for all surgical patients. The slides can be retrieved under Electronic Supplementary Material.

Nutrient foramen location on the laminae provides a landmark for pedicle screw entry: a cadaveric study.

BACKGROUND: Nutrient foramina are often encountered around the entry point of pedicle screws. Further, while probing the pedicle for pedicle screw insertion around the nutrient foramen, bleeding from the probe insertion hole is often observed. The purpose of this study was to investigate the frequency of occurrence of nutrient foramina, the association between the nutrient foramen and pedicle, and the safety and accuracy of cervical and thoracic pedicle screw placement using the nutrient foramen as the entry point. METHODS: We identified the location of the nutrient foramina for the dorsal branches of the segmental artery and their anatomical association to the pedicles and bony landmarks in the vertebrae for C3-T12 in seven cadavers. We also determined the frequency with which the nutrient foramina were present in 119 cadaveric vertebrae. We identified the pedicle location, base of the superior articular facet, and lateral border of laminae with respect to the nutrient foramen. RESULTS: The overall presence of the nutrient foramina was 63% (150/238) in the specimens, with 60% (42/70) and 64% (108/168) identifiable in the cervical and thoracic vertebrae, respectively. In the cervical vertebrae, the nutrient foramen was located on the outer wall of the pedicle and was positioned between the cephalad and caudal walls. In the thoracic spine, 98% (106/108) nutrient foramina were located inside the pedicle walls. CONCLUSIONS: Our study findings confirm that the location of the nutrient foramen can be used for identifying the entry point for pedicle screws. In the cervical vertebrae, the nutrient foramina are located lateral to pedicle but within the cranial and caudal margins. In the thoracic vertebrae, the nutrient foramina are located in the medial and caudal regions of the pedicle. Thus, to decrease the risk of overshoot, the entry point for thoracic pedicle screws should be positioned a few millimeters cephalad and lateral to the nutrient foramen.

Comparison of surgical outcomes for cervical radiculopathy by nerve root level.

Cervical radiculopathy might affect finger movement and dexterity. Postoperative features and clinical outcomes comparing C8 radiculopathies with other radiculopathies are unknown. This prospective multicenter study analyzed 359 patients undergoing single-level surgery for pure cervical radiculopathy (C5, 48; C6, 132; C7, 149; C8, 30). Background data and pre- and 1-year postoperative neck disability index (NDI) and numerical rating scale (NRS) scores were collected. The C5-7 and C8 radiculopathy groups were compared after propensity score matching, with clinical significance determined by minimal clinically important differences (MCID). Postoperative arm numbness was significantly higher than upper back or neck numbness, and arm pain was reduced the most (3.4 points) after surgery among the C5-8 radiculopathy groups. The C8 radiculopathy group had worse postoperative NDI scores (p = 0.026), upper back pain (p = 0.042), change in arm pain NRS scores (p = 0.021), and upper back numbness (p = 0.028) than the C5-7 group. NDI achieved MCID in both groups, but neck and arm pain NRS did not achieve MCID in the C8 group. In conclusion, although arm numbness persisted, arm pain was relieved after surgery for cervical radiculopathy. Patients with C8 radiculopathy exhibited worse NDI and change in NRS arm pain score than those with C5-7 radiculopathy.

Impact of incidental dural tears on postoperative outcomes in patients undergoing cervical spine surgery: a multicenter retrospective cohort study.

BACKGROUND CONTEXT: Incidental dural tear (DT) during cervical spine surgery is a feared complication. However, its impact on patient-reported outcomes (PROs) remains unclear. PURPOSE: To determine the influence of DTs on PROs 1 year after cervical spine surgery. STUDY DESIGN: Retrospective cohort. PATIENT SAMPLE: Patients undergoing elective cervical spine surgery for cervical spondylosis, ossification of the posterior longitudinal ligament (OPLL), and cervical disc herniation. OUTCOME MEASURES: Analysis included patients' characteristics, perioperative complications, and PROs both preoperatively and at 1 year postoperatively. METHODS: This study enrolled consecutive patients who underwent elective cervical spine surgery at 13 high-volume spine centers. All patients were required to complete questionnaires both preoperatively and 1 year postoperatively, which included PROs such as numerical rating scales of pain or dysesthesia for each part of the body, Neck Disability Index NDI, and Core Outcome Measures Index. Patients were divided into 2 groups based on the presence (DT+) or absence (DT-) of dural injury. Comparisons were made regarding patient background, perioperative complications, and pre and postoperative PROs. Propensity score matching was also utilized to adjust for patient background, and further comparisons were made regarding complication rates and PROs. RESULTS: Out of 2,704 patients, dural tears were identified in 97 (3.6%) cases. The DT+ group had a significantly higher proportion of fixation surgeries, upper cervical surgeries, OPLL, and revision surgeries. Perioperative complications were significantly higher in the DT+ group, including intraoperative nerve damage, postoperative paralysis, surgical site infections (SSI), and cerebrovascular complications. Outcomes collected from 2,163 patients (79.9%) revealed significantly more severe neck and upper limb pain in the DT+ group. After propensity score matching, significant differences persisted in postoperative paralysis and SSI in the DT+ group, but no significant differences were observed in PROs. CONCLUSIONS: Patients with dural tears showed nearly equivalent postoperative outcomes at 1 year following cervical spine surgery compared to those without dural tears. However, the incidence of perioperative complications was higher, emphasizing the need for careful management.

Patient-Reported Outcomes and Patient Satisfaction Following Surgery for Thoracic Myelopathy.

Introduction: The association between postoperative patient-reported outcomes (PROs) and patient satisfaction remains poorly defined in patients undergoing surgery for thoracic myelopathy. This study aimed to investigate PROs and patient satisfaction following surgical intervention for thoracic myelopathy. Methods: A prospective cohort of 133 patients who underwent surgery for thoracic myelopathy at 13 hospitals between April 2017 and August 2021 was enrolled. Patient demographics and perioperative complications were recorded. PROs were assessed using questionnaires administered preoperatively and 1 year postoperatively, including the EuroQol-5 dimension, physical and mental component summaries of the 12-item Short-Form Health Survey, Oswestry Disability Index, and numerical rating scales for low back, lower extremity, and plantar pain. Patients were categorized into two groups: satisfied (very satisfied, satisfied, and slightly satisfied) and dissatisfied (neither satisfied nor dissatisfied, slightly dissatisfied, dissatisfied, and very dissatisfied). Results: The mean age of the patients was 66.5 years, comprising 87 men and 46 women. The most common diagnoses were ossification of the ligamentum flavum (48.8%) and thoracic spondylotic myelopathy (26.3%). Seventy-four (55.6%) and 59 (44.3%) patients underwent decompression surgery and underwent decompression with fusion, respectively. Eight patients required reoperation due to postoperative surgical site infection, hematoma, and insufficient decompression in four, three, and one patient. Ninety (67.7%) patients completed both the preoperative and postoperative PRO questionnaires, all of which demonstrated significant improvement. Among them, 58 (64.4%) and 32 (35.6%) reported satisfaction and dissatisfaction with their treatment, respectively. The satisfied group showed superior improvement in PROs than the dissatisfied group, although there were no significant differences in complication rates between the two groups. Conclusions: The 64.4% satisfaction rate observed in patients undergoing surgery for thoracic myelopathy was lower than that reported in previous studies on cervical or lumbar spine surgery. The dissatisfied group exhibited significantly poorer quality of life (QOL) and higher pain scores than the satisfied group.

Validity, reliability and responsiveness of the Japanese version of the Neck Disability Index.

BACKGROUND: The Neck Disability Index (NDI) is one of the most widely used questionnaires for neck pain. The purpose of this study was to validate the Japanese NDI. METHODS: We performed two surveys with an 8-week interval in 130 patients with neck pain, radiculopathy and myelopathy. We asked patients to answer two versions of the Japanese NDI: the original NDI, which had been completed by a forward-backward translation procedure, and the modified NDI, which has the phrase "because of neck pain" to the phase "because of neck pain or numbness in the arm." The other parameters examined were the strength of pain and numbness, the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire, the Hospital Anxiety and Depression Scale, and Short Form 36. Attending surgeons judged the symptom severity. Patients were asked to report the patient global impression of change (PGIC) at the second survey. The internal consistency, criterion-related and discriminative validity, and reliability were evaluated. RESULTS: The original NDI and the modified NDI were 26.9 ± 17.1 and 29.9 ± 15.5, respectively. The Cronbach α values of the original NDI and the modified NDI were 0.92 and 0.89, respectively. Both versions of the NDI had good to excellent correlative coefficients with the related domains. The modified NDI had a higher validity for numbness and mental health-related QOL. The symptom severity was significantly correlated with the modified NDI. The intraclass correlation coefficients of the two surveys of the modified and original NDI were comparable. The effect sizes of the modified and the original NDI were 0.64 and 0.55, respectively. Spearman's ρ between the change of the NDI and the PGIC was 0.47 in the original NDI and 0.59 in the modified NDI. CONCLUSIONS: We demonstrated the validity, reliability and responsiveness of the Japanese NDI. The modified NDI was more strongly correlated with numbness and mental health-related QOL.

A Propensity Score-matched Analysis of Clinical Outcomes Between Single-level and Multilevel Intervertebral Decompression for Cervical Radiculopathy.

STUDY DESIGN: Retrospective multicenter study with propensity score matching. OBJECTIVE: To compare the clinical outcomes of single-level and multilevel intervertebral decompression for cervical degenerative radiculopathy. SUMMARY OF BACKGROUND DATA: In patients with cervical radiculopathy, physical examination findings are sometimes inconsistent with imaging data. Multilevel decompression may be necessary for multiple foraminal stenosis. Additional decompression is more invasive yet expected to comprehensively decompress all suspected nerve root compression areas. However, the surgical outcomes of this approach compared with that of single-level decompression remain unknown. MATERIALS AND METHODS: The data of patients with spinal surgery for pure cervical radiculopathy were collected. Patients were categorized into the single-level (SLDG) or multilevel (MLDG) intervertebral decompression group at C3/C4/C5/C6/C7/T1. Demographic data and patient-reported outcome scores, including the Neck Disability Index (NDI) and Numerical Rating Scale (NRS) scores for pain and numbness in the neck, upper back, and arms, were collected. The NDI improvement rates and changes in NRS scores were analyzed one year postoperatively at patient-reported outcome evaluation. Propensity score matching was performed to compare both groups after adjusting for baseline characteristics, including the preoperative NDI and NRS scores. RESULTS: Among the 357 patients in this study, SLDG and MLDG comprised 231 and 126 patients, respectively. Two groups (n=112, each) were created by propensity score matching. Compared with the MLDG, the SLDG had a higher postoperative NDI improvement rate ( P =0.029) and lower postoperative arm numbness NRS score ( P =0.037). Other outcomes tended to be more favorable in the SLDG than in the MLDG, yet no statistical significance was detected. CONCLUSIONS: In patients with cervical radiculopathy, the surgical outcomes of the SLDG showed better improvement in clinical outcomes than those of the MLDG. Numbness remained on the distal (arms) rather than the central (neck and upper back) areas in patients receiving multilevel decompression.

Quality of Life and Postoperative Satisfaction in Patients with Benign Extramedullary Spinal Tumors: A Multicenter Study.

STUDY DESIGN: Retrospective cohort study using prospectively collected registry data. OBJECTIVE: The purpose of this study is to evaluate health-related quality of life (HRQOL) and postoperative satisfaction in patients with different histotypes of benign extramedullary spinal tumors (ESTs). BACKGROUND: Little is known about how different histotypes influence HRQOL and postoperative satisfaction in EST patients. MATERIALS AND METHODS: Patients undergoing primary benign EST surgery at 11 tertiary referral hospitals between 2017 and 2021 who completed preoperative and 1-year postoperative questionnaires were included. HRQOL assessment included the Physical Component Summary and Mental Component Summary (MCS) of Short Form-12, EuroQol 5-dimension, Oswestry/Neck Disability Index (ODI/NDI), and Numeric Rating Scales (NRS) for upper/lower extremities (UEP/LEP) and back pain (BP). Patients who answered "very satisfied," "satisfied," or "somewhat satisfied" on a seven-point Likert scale were considered to be satisfied with treatment. Student t -tests or Welch's t -test were used to compare continuous variables between two groups, and one-way analysis of variance was used to compare outcomes between the three groups of EST histotypes (schwannoma, meningioma, atypical). Categorical variables were compared using the χ 2 test or Fisher exact test. RESULTS: A total of 140 consecutive EST patients were evaluated; 100 (72%) had schwannomas, 30 (21%) had meningiomas, and 10 (7%) had other ESTs. Baseline Physical Component Summary was significantly worse in patients with meningiomas ( P =0.04), and baseline NRS-LEP was significantly worse in patients with schwannomas ( P =0.03). However, there were no significant differences in overall postoperative HRQOL or patient satisfaction between histology types. Overall, 121 (86%) patients were satisfied with surgery. In a subgroup analysis comparing intradural schwannomas and meningiomas adjusted for patient demographics and tumor location with inverse probability weighting, schwannoma patients had worse baseline MCS ( P =0.03), ODI ( P =0.03), NRS-BP ( P <.001), and NRS-LEP ( P =0.001). Schwannoma patients also had worse postoperative MCS ( P =0.03) and NRS-BP ( P =0.001), with no significant difference in the percentage of satisfied patients ( P =0.30). CONCLUSIONS: Patients who underwent primary benign EST resection had a significant improvement in HRQOL postoperatively, and ~90% of these patients reported being satisfied with their treatment outcomes one year after surgery. EST patients may exhibit a relatively lower threshold for postoperative satisfaction compared with patients undergoing surgery for degenerative spine conditions.

Impact of body mass index on outcomes after lumbar spine surgery.

The impact of body mass index (BMI) on outcomes after lumbar spine surgery is currently unknown. Previous studies have reported conflicting evidence for patients with high BMI, while little research has been conducted on outcomes for underweight patients. This study aims to examine the impact of BMI on outcomes after lumbar spine surgery. This prospective cohort study enrolled 5622 patients; of which, 194, 5027, and 401 were in the low (< 18.5 kg/m2), normal (18.5-30), and high (≥ 30) BMI groups, respectively. Pain was assessed via the numerical pain rating scale (NPRS) for the lower back, buttock, leg, and plantar area. Quality of life was assessed via the EuroQol 5 Dimension (EQ-5D) and Oswestry Disability Index (ODI). Inverse probability weighting with propensity scores was used to adjust patient demographics and clinical characteristics between the groups. After adjustment, the 1-year postoperative scores differed significantly between groups in terms of leg pain. The proportion of patients who achieved a 50% decrease in postoperative NPRS score for leg pain was also significantly different. Obese patients reported less improvement in leg pain after lumbar spine surgery. The outcomes of patients with low BMI were not inferior to those of patients with normal BMI.

Treatment of restenosis after lumbar decompression surgery: decompression versus decompression and fusion.

OBJECTIVE: The aim of this study was to compare perioperative complications and postoperative outcomes between patients with lumbar recurrent stenosis without lumbar instability and radiculopathy who underwent decompression surgery and those who underwent decompression with fusion surgery. METHODS: For this retrospective study, the authors identified 2606 consecutive patients who underwent posterior surgery for lumbar spinal canal stenosis at eight affiliated hospitals between April 2017 and June 2019. Among these patients, those with a history of prior decompression surgery and central canal restenosis with cauda equina syndrome were included in the study. Those patients with instability or radiculopathy were excluded. The patients were divided between the decompression group and decompression with fusion group. The demographic characteristics, numerical rating scale score for low-back pain, incidence rates of lower-extremity pain and lower-extremity numbness, Oswestry Disability Index score, 3-level EQ-5D score, and patient satisfaction rate were compared between the two groups using the Fisher's exact probability test for nominal variables and the Student t-test for continuous variables, with p < 0.05 as the level of statistical significance. RESULTS: Forty-six patients met the inclusion criteria (35 males and 11 females; 19 patients underwent decompression and 27 decompression and fusion; mean ± SD age 72.5 ± 8.8 years; mean ± SD follow-up 18.8 ± 6.0 months). Demographic data and perioperative complication rates were similar. The percentages of patients who achieved the minimal clinically important differences for patient-reported outcomes or satisfaction rate at 1 year were similar. CONCLUSIONS: Among patients with central canal stenosis who underwent revision, the short-term outcomes of the patients who underwent decompression were comparable to those of the patients who underwent decompression and fusion. Decompression surgery may be effective for patients without instability or radiculopathy.

The Diagnostic Value of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for the Detection of Surgical Site Infection after Spine Surgery.

STUDY DESIGN: Retrospective case series. OBJECTIVE: The purpose of this study was to assess the diagnostic yield of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) for surgical site infection (SSI) after spine surgery. SUMMARY OF BACKGROUND DATA: Diagnosis of SSI in the spine based on F-18 FDG PET/CT requires experienced nuclear medical physicians for a detailed analysis of F-18 FDG distribution pattern. It has also been reported that increases in the maximal standardized uptake values of F-18 FDG (SUVmax) closely correlated with SSI, suggesting potential of more objective and quantitative diagnosis. METHODS: We assessed the diagnostic yield of F-18 FDG PET/CT (pattern-based diagnosis by nuclear medical physicians and SUVmax-based diagnosis) for SSI in 52 subjects who underwent spine surgery. The 52 subjects included 11 nonimplant and 41 implant cases. F-18 FDG PET/CT was performed in 33 and 19 cases in early (≤12 weeks after the surgery) and late (>12 weeks) phases, respectively. The final diagnosis of SSI was based on the results of pathogen identification, plain radiography, and CT and/or magnetic resonance imaging or response to antibiotics and/or reoperation. RESULTS: SUVmax-based diagnosis was performed with a cut off value of 5.0 as determined by receiver operating characteristic analysis. Both pattern-based and SUVmax-based diagnoses demonstrated excellent diagnostic yields with high sensitivity (97% and 90%), specificity (100% and 100%), and accuracy (98% and 94%). High diagnostic yields (accuracy of ≥90%) were consistently observed irrespective of presence or absence of implantation or interval between surgery and F-18 FDG PET/CT. CONCLUSION: F-18 FDG PET/CT can be the procedure of choice for investigation of SSI in the spine when other imaging fails to provide a definitive diagnosis.Level of Evidence: 4.

C5 palsy after C5/6/7 posterior foraminal decompression: A case report.

RATIONALE: Although C5 palsy is a common complication of cervical spine surgery, its cause has not been confirmed. There are various hypotheses for its mechanism, including spinal cord impairment and nerve involvement. Therefore, prophylactic foraminotomy is one of the methods recommended for preventing C5 palsy. However, we describe a patient who experienced C5 palsy after microendoscopic foraminotomy between the left C5/6 and C6/7 levels. PATIENT CONCERNS: A 43-year-old man presented with a 14-month history of progressive numbness in the left upper limb. We performed microendoscopic left foraminal decompressions at the C5/6/7 levels to treat the left C6 and C7 radiculopathy. On the postoperative day 1, we observed weak motor strength of the left deltoid, left biceps, and left forearm pronator, while the motor strength of the other muscles was normal. DIAGNOSES: C5 palsy following C5/6/7 left foraminotomy. INTERVENTION: Follow-up rehabilitation with muscle strength training and range of motion training. OUTCOME: The patient recovered his motor strength completely within 3 months postoperatively. LESSONS: In this case, the C5 palsy could not be adequately explained by the theory of nerve root impingement or disruption in blood circulation following spinal cord decompression. We hypothesized that the patient had drill heat-induced C5 palsy. Regarding the C5 palsy without C5 nerve root decompression, we hypothesize that the C5 palsy in C5/6/7 foraminotomy could be related to variations in the formation of the brachial plexus. Prophylactic foraminotomy for cervical posterior surgery should be performed with care, limiting its use in patients who are at a risk of developing C5 palsy because the prophylactic procedure can cause C5 palsy. We must also consider that even without decompression at the C4/5 level, there is a possibility of C5 palsy occurring.

Incidence, prognosis, and risk factors for bladder and bowel dysfunction due to incidental dural tears in lumbar microendoscopic surgery.

BACKGROUND CONTEXT: Despite the common occurrence of incidental dural tears, the incidence and prognosis of bladder and bowel dysfunction (BBD) due to incidental dural tears in lumbar spinal surgery are not well known because of the lack of reported cases. PURPOSE: To analyze the incidence, prognosis, and risk factors for BBD after lumbar microendoscopic surgery with or without incidental dural tears. STUDY DESIGN/SETTING: A retrospective cohort study. PATIENT SAMPLE: We analyzed 2,421 patients who underwent lumbar microendoscopic surgery and investigated patients with BBD after an incidental durotomy during surgery. OUTCOME MEASURES: Patients were divided into three groups on the basis of dysuria and defecation disorders: severe BBD, mild BBD, and no BBD. The post void residual volumes before and after surgery were compared using an ultrasound bladder scanner or bladder catheterization after confirmation of urination. Bowel dysfunction was evaluated by subjective symptomatic deterioration and the increase in the frequency and duration of postoperative medical care. METHODS: Risk factors for BBD were analyzed using surgical video documentation to determine the dural tear site and cauda equina exposure from the dural sac. Patients with BBD were prospectively followed up for prognosis determination. The chi-square test was used to compare the incidence of BBD between patients with dural tears and those without. Propensity score-adjusted logistic regression analysis was performed to evaluate the effects of various factors on the incidence of postoperative BBD. RESULTS: The incidence of dural tears was 6.9% (168/2,421). The overall incidence of BBD was 3.0% (73/2,421), while the incidences of BBD (mild+severe BBD) and severe BBD due to incidental dural tears were 1.2% (30/2,421) and 0.8% (20/2,421), respectively. The incidence of BBD in patients with dural tears and those without tears was 17.9% [30/168] and 1.9% [43/2,253; p<.001]), respectively. BBD rates at 1 week, 1 month, 3 months, 6 months, and 1 year after surgery were 64.0%, 44.0%, 40.0%, 28.0%, and 13.6%, respectively. Logistic regression analysis revealed that the male sex (odds ratio [OR], 4.20), dural tears in the central area (OR, 10.15), and exposure of the cauda equina (OR, 51.04) were significant risk factors. CONCLUSIONS: The incidence of dural tears in lumbar microendoscopic surgeries are associated with an increased incidence of BBD. The recovery rate for BBD due to incidental dural tears is generally good; however, some patients experience long-term symptoms. Clinicians should be aware that incidental dural tears with cauda equina exposure can increase the risk of BBD.

Is Microendoscopic Discectomy Effective for Patients With Concomitant Lumbar Disc Herniation and Spondylolysis?

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: Although it is controversial whether to choose only discectomy or fusion surgery in patients with disc herniation and spondylolysis, we expected that aggravation of the spondylolysis may be prevented if posterior supporting muscles can be well-preserved without extensive exploration. The purpose of this study was to investigate the influence of L5 spondylolysis on surgical outcomes following microendoscopic discectomy (MED) in patients with concomitant lumbar disc herniation and spondylolysis. METHODS: We reviewed 811 patients who underwent MED for L4/5 or L5/S1 disc herniation. Patients with spondylolisthesis were excluded. We compared surgical outcomes of patients with and without L5 spondylolysis, whose age, sex, and surgical level were matched. RESULTS: A total of 655 patients (80.7%) with complete data were considered eligible for the study. MED was performed at L4/5 and L5/S1 in 338 and 317 patients, respectively. A total of 20 patients (3.1%) had concomitant L5 spondylolysis and disc herniation at L4/5 (9 patients) or L5S1 (11 patients). As we compared each outcome of the 20 patients having L5 spondylolysis with 40 matched patients without L5 spondylosis, there were no significant differences in preoperative or postoperative outcomes between the 2 groups, and no patient with spondylolysis had undergone additional surgery during the mean follow-up period of 24 months. CONCLUSIONS: MED demonstrated good surgical results regardless of the presence or absence of spondylolysis. In patients with sciatica with concomitant disc herniation and spondylolysis, but without spondylolisthesis, fusion surgery may not be always necessary.