Morphological features of lower lumbar degenerative kyphosis.

PURPOSE: Kyphosis in the lower lumbar spine (L4-S1) significantly affects sagittal alignment. However, the characteristics of the spinopelvic parameters and compensatory mechanisms in patients with lower lumbar degenerative kyphosis (LLDK) have not been described in detail. The objective of this retrospective study was to analyze the morphological characteristics in patients with sagittal imbalance due to LLDK. METHODS: In this retrospective study, we reviewed the clinical records of consecutive patients who underwent corrective surgery for adult spinal deformity (ASD) at a single institution. We defined LLDK as (i) kyphotic deformity in lower lumbar spine (L4-S1) or (ii) inappropriate distribution of lordosis (lordosis distribution index < 40%) in the lower lumbar spine. Global spine parameters of ASD patients and MRI findings were compared between those with LLDK (LLDK group) and without LLDK (control group). RESULTS: A total of 95 patients were enrolled in this study, of which the LLDK group included 14 patients (14.7%). Compared to the control, LLDK presented significantly higher pelvic incidence (62.1° vs 52.6°) and pelvic tilt (40.0° vs 33.4°), larger lordosis at the thoracolumbar junction (12.0° vs -19.6°), and smaller thoracic kyphosis (9.3° vs 26.0°). In LLDK, there was significantly less disc degeneration at L2/3 and L3/4. CONCLUSION: LLDK patients had high pelvic incidence, large pelvic tilt, and a long compensatory curve at the thoracolumbar junction and thoracic spine region.

The impact of diabetes mellitus on spinal fracture with diffuse idiopathic skeletal hyperostosis: A multicenter retrospective study.

BACKGROUND: Patients with diffuse idiopathic skeletal hyperostosis (DISH) are susceptible to spinal column injuries with neurological deterioration. Previous studies indicated that the prevalence of diabetes mellitus (DM) in patients with DISH was higher than that in patients without DISH. This study investigates the impact of DM on surgical outcomes for spinal fractures in patients with DISH. METHODS: We retrospectively evaluated 177 spinal fractures in patients with DISH (132 men and 45 women; mean age, 75 ± 10 years) who underwent surgery from a multicenter database. The subjects were classified into two groups according to the presence of DM. Perioperative complications, neurological status by Frankel grade, mortality rate, and status of surgical site infection (SSI) were compared between the two groups. RESULTS: DM was present in 28.2% (50/177) of the patients. The proportion of men was significantly higher in the DM group (DM group: 86.0% vs. non-DM group: 70.1%) (p = 0.03). The overall complication rate was 22.0% in the DM group and 19.7% in the non-DM group (p = 0.60). Poisson regression model revealed that SSI was significantly associated with DM (DM group: 10.0% vs. non-DM group: 2.4%, Relative risk: 4.5) (p = 0.048). Change in neurological status, mortality rate, instrumentation failure, and nonunion were similar between both groups. HbA1c and fasting blood glucose level (SSI group: 7.2% ± 1.2%, 201 ± 67 mg/dL vs. non-SSI group: 6.6% ± 1.1%, 167 ± 47 mg/dL) tended to be higher in patients with SSI; however, there was no significant difference. CONCLUSIONS: In spinal fracture in patients with DISH, although DM was an associated factor for SSI with a relative risk of 4.5, DM did not negatively impact neurological recovery. Perioperative glycemic control may be useful for preventing SSI because fasting blood glucose level was high in patients with SSI.

Pelvic incidence change on the operating table.

PURPOSE: While a change in the pelvic incidence (PI) after long spine fusion surgery has been reported, no studies have examined the change in the PI on the operating table. The present study examined the PI-change on the operating table and elucidated the patients' background characteristics associated with this phenomenon. METHODS: This study included patients who underwent lumbar posterior spine surgery and had radiographs taken in a full-standing position preoperatively and a pelvic lateral radiograph in the prone position in the operative room. The patients with PI-change on the operating table (PICOT; PICOT group) and without PICOT (control group) were compared for their background characteristics and preoperative radiographic parameters. RESULTS: There were 128 eligible patients (62 males, 66 females) with a mean age (± standard deviation) of 69.9 ± 11.7 (range: 25-93) years old. Sixteen patients (12.5%) showed a decrease in the PI > 10°, which indicated placement in the PICOT group. The preoperative lumbar lordosis (LL) and PI-LL in the PICOT group were significantly worse than those in the control group (LL: 20.8 ± 16.6 vs. 30.6 ± 16.2, p = 0.0251, PI-LL: 33.9 ± 19.0 vs. 17.3 ± 14.8, p < 0.0001). The PICOT group had a higher proportion of patients who underwent fusion surgery than the control group, but the difference was not significant (62.5% vs. 44.6%, p = 0.1799). CONCLUSION: A decreased PI was observed in some patients who underwent lumbar posterior surgery on the operating table before surgery. Patients with a PI decrease on the operating table had a significantly worse preoperative global alignment than those without such a decrease. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Adverse effects of surgeon performance after a night shift on the incidence of perioperative complications in elective thoracolumbar spine surgery.

BACKGROUND: Decline in cognitive function after night shift has been well described. However, in the field of spine surgery, the effect of surgeons' sleeplessness on patient outcome is unclear. The purpose of this study was to investigate whether the risk of perioperative complications in elective thoracolumbar spine surgery could be higher if the surgeon had been on a night shift prior to the day of surgery. METHODS: We performed a retrospective review of patients who underwent elective posterior thoracolumbar spine surgery, as indicated in medical records, between March 2015 and September 2018. In total, 1189 patients were included and divided into two groups: the post-nighttime (n = 110) and control groups (n = 1079). A post-nighttime case was defined when the operating surgeon was on nighttime duty on the previous night, and other cases were defined as controls. We evaluated the incidence of perioperative complications (surgical site infection, postoperative hematoma, postoperative paralysis, nerve root injury, and dural tear) in both groups. RESULTS: Overall, we found no significant difference in the major or minor perioperative complication rates between the two groups, but according to the type of complication, the incidence rate of dural tear tended to be higher in the post-nighttime group (13.6% vs 8.2%, P = 0.074). Multivariate analysis showed that post-nighttime status was an independent risk factor of dural tear (adjusted odds ratio, 2.02; 95% confidence interval [CI], 1.10-3.70; P = 0.023). After stratification by surgical complexity, post-nighttime status was an independent risk factor of dural tear only in the surgeries of 3 levels or more (adjusted odds ratio, 2.81; 95% CI, 1.18-6.67; P = 0.019). CONCLUSIONS: Post-nighttime status was generally not a risk factor of perioperative complications in elective posterior thoracolumbar spine surgeries, but was an independent risk factor of dural tear, especially in complex cases.

Risk factors for delayed diagnosis of spinal fracture associated with diffuse idiopathic skeletal hyperostosis: A nationwide multiinstitution survey.

BACKGROUND: Patients with DISH are susceptible to spinal fractures and subsequent neurological impairment, including after minor trauma. However, DISH is often asymptomatic and fractures may have minimal symptoms, which may lead to delayed diagnosis. The purpose of this study was to identify risk factors for delayed diagnosis of spinal fractures in patients with diffuse idiopathic skeletal hyperostosis (DISH). METHODS: The subjects were 285 patients with DISH surgically treated at 18 medical centers from 2005 to 2015. Cause of injury, imaging findings, neurological status at the times of injury and first hospital examination, and the time from injury to diagnosis were recorded. A delayed diagnosis was defined as that made >24 h after injury. RESULTS: Main causes of injury were minor trauma due to a fall from a standing or sitting position (51%) and high-energy trauma due to a fall from a high place (29%) or a traffic accident (12%). Delayed diagnosis occurred in 115 patients (40%; 35 females, 80 males; mean age 76.0 ± 10.4 years), while 170 (60%; 29 females, 141 males; mean age 74.6 ± 12.8 years) had early diagnosis. Delayed group had a significantly higher rate of minor trauma (n = 73, 63% vs. n = 73, 43%), significantly more Frankel grade E (intact neurological status) cases at the time of injury (n = 79, 69% vs. n = 73, 43%), and greater deterioration of Frankel grade from injury to diagnosis (34% vs. 8%, p < 0.01). In multivariate analysis, a minor trauma fall (OR 2.08; P < 0.05) and Frankel grade E at the time of injury (OR 2.29; P < 0.01) were significantly associated with delayed diagnosis. CONCLUSION: In patients with DISH, it is important to keep in mind the possibility of spinal fracture, even in a situation in which patient sustained only minor trauma and shows no neurological deficit. This is because delayed diagnosis of spinal fracture can cause subsequent neurological deterioration.

Spinal fractures in patients with Diffuse idiopathic skeletal hyperostosis:A nationwide multi-institution survey.

BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) increases the spine's susceptibility to unstable fractures that can cause neurological deterioration. However, the detail of injury is still unclear. A nationwide multicenter retrospective study was conducted to assess the clinical characteristics and radiographic features of spinal fractures in patients with DISH. METHODS: Patients were eligible for this study if they 1) had DISH, defined as flowing ossification along the anterolateral aspect of at least four contiguous vertebral bodies, and 2) had an injury in the ankylosing spine. This study included 285 patients with DISH (221 males, 64 females; mean age 75.2 ± 9.5 years). RESULTS: The major cause of injury was falling from a standing or sitting position; this affected 146 patients (51.2%). Diagnosis of the fracture was delayed in 115 patients (40.4%). Later neurological deterioration by one or more Frankel grade was seen in 87 patients (30.5%). The following factors were significantly associated with neurological deficits: delayed diagnosis (p = 0.033), injury of the posterior column (p = 0.021), and the presence of ossification of the posterior longitudinal ligament (OPLL) (p < 0.001). The majority of patients (n = 241, 84.6%) were treated surgically, most commonly by conventional open posterior fixation (n = 199, 69.8%). Neurological improvement was seen in 20.0% of the conservatively treated patients, and in 47.0% of the patients treated surgically. CONCLUSIONS: Minor trauma could cause spinal fractures in DISH patients. Delayed diagnosis, injury of the posterior column, and the presence of OPLL were significantly associated with neurological deterioration. Patients with neurological deficits or unstable fractures should be treated by fixation surgery.

Mini-open anterior approach for cervicothoracic junction fracture: technical note.

Elderly patients with diffuse idiopathic skeletal hyperostosis are at high risk for falls, and 3-column unstable fractures present multiple challenges. Unstable fractures across the cervicothoracic junction are associated with significant morbidity and require fixation, which is commonly performed through a posterior open or percutaneous approach. The authors describe a novel, navigated, mini-open anterior approach using intraoperative cone-beam CT scanning to place lag screws followed by an anterior plate in a 97-year-old patient. This approach is less invasive and faster than an open posterior approach and can be considered as an option for management of cervicothoracic junction fractures in elderly patients with high perioperative risk profile who cannot tolerate being placed prone during surgery.

Technique and nuances of an S-2 alar iliac screw for lumbosacral fixation in patients with transitional and normal anatomy.

S-2 alar iliac (S2AI) screw fixation has recently been recognized as a useful technique for pelvic fixation. The authors demonstrate two cases where S2AI fixation was indicated: one case was a sacral insufficiency fracture following a long-segment fusion in a patient with a transitional S-1 vertebra; the other case involved pseudarthrosis following lumbosacral fixation. S2AI screws offer rigid fixation, low profile, and allow easy connection to the lumbosacral rod. The authors describe and demonstrate the surgical technique and nuances for the S2AI screw in a case with transitional S-1 anatomy and in a case with normal S-1 anatomy. The video can be found here: https://youtu.be/Sj21lk13_aw .

Does the microendoscopic technique reduce mortality and major complications in patients undergoing lumbar discectomy? A propensity score-matched analysis using a nationwide administrative database.

OBJECTIVE Although minimally invasive spinal surgery has recently gained popularity, few nationwide studies have compared the adverse events that occur during endoscopic versus open spinal surgery. The purpose of this study was to compare perioperative complications associated with microendoscopic discectomy (MED) and open discectomy for patients with lumbar disc herniation. METHODS The authors retrospectively extracted from the Diagnosis Procedure Combination database, a national inpatient database in Japan, data for patients admitted between July 2010 and March 2013. Patients who underwent lumbar discectomy without fusion surgery were included in the analysis, and those with an urgent admission were excluded. The authors examined patient age, sex, Charlson Comorbidity Index, body mass index, smoking status, blood transfusion, duration of anesthesia, type of hospital, and hospital volume (number of patients undergoing discectomy at each hospital). One-to-one propensity score matching between the MED and open discectomy groups was performed to compare the proportions of in-hospital deaths, surgical site infections (SSIs), and major complications, including stroke, acute coronary events, pulmonary embolism, respiratory complications, urinary tract infection, and sepsis. The authors also compared the hospital length of stay between the 2 groups. RESULTS A total of 26,612 patients were identified in the database. The mean age was 49.6 years (SD 17.7 years). Among all patients, 17,406 (65.4%) were male and 6422 (24.1%) underwent MED. A propensity score-matched analysis with 6040 pairs of patients showed significant decreases in the occurrence of major complications (0.8% vs 1.3%, p = 0.01) and SSI (0.1% vs 0.2%, p = 0.02) in patients treated with MED compared with those who underwent open discectomy. Overall, MED was associated with significantly lower risks of major complications (OR 0.62, 95% CI 0.43-0.89, p = 0.01) and SSI (OR 0.29, 95% CI 0.09-0.87, p = 0.03) than open discectomy. There was a significant difference in length of hospital stay (11 vs 15 days, p < 0.001) between the groups. There was no significant difference in in-hospital mortality between MED and open discectomy. CONCLUSIONS The microendoscopic technique was associated with lower risks for SSI and major complications following discectomy in patients with lumbar disc herniation.

The endoscopic transoral approach to the craniovertebral junction: an anatomical study with a clinical example.

OBJECTIVE The microscopic transoral, endoscopic transnasal, and endoscopic transoral approaches are used alone and in combination for a variety of craniovertebral junction (CVJ) pathologies. The endoscopic transoral approach provides a more direct exposure that is not restricted by the nasal cavity, pterygoid plates, and palate while sparing the potential morbidities associated with extensive soft-tissue dissection, palatal splitting, or mandibulotomy. Concerns regarding the extent of visualization afforded by the endoscopic transoral approach may be limiting its widespread adoption. METHODS A dissection of 10 cadaver heads was undertaken. CT-based imaging guidance was used to measure the working corridor of the endoscopic transoral approach. Measurements were made relative to the palatal line. The built-in linear measurement tool was used to measure the superior and inferior extents of view. The superolateral extent was measured relative to the midline, as defined by the nasal process of the maxilla. The height of the clivus, odontoid tip, and superior aspect of the C-1 arch were also measured relative to the palatal line. A correlated clinical case is presented with video. RESULTS The CVJ was accessible in all cases. The superior extent of the approach was a mean 19.08 mm above the palatal line (range 11.1-27.7 mm). The superolateral extent relative to the midline was 15.45 mm on the right side (range 9.6-23.7 mm) and 16.70 mm on the left side (range 8.1-26.7 mm). The inferior extent was a mean 34.58 mm below the palatal line (range 22.2-41.6 mm). The mean distances were as follows: palatal line relative to the odontoid tip, 0.97 mm (range -4.9 to 3.7 mm); palatal line relative to the height of the clivus, 4.88 mm (range -1.5 to 7.3 mm); and palatal line relative to the C-1 arch, -2.75 mm (range -5.8 to 0 mm). CONCLUSIONS The endoscopic transoral approach can reliably access the CVJ. This approach avoids the dissections and morbidities associated with a palate-splitting technique (velopharyngeal insufficiency) and the expanded endonasal approach (mucus crusting, sinusitis, and potential lacerum or cavernous-paraclival internal carotid artery injury). For appropriately selected lesions near the palatal line, the endoscopic transoral approach appears to be the preferred approach.

Perioperative stroke in patients undergoing elective spinal surgery: a retrospective analysis using the Japanese diagnosis procedure combination database.

BACKGROUND: Although a few studies on perioperative stroke following spinal surgery have been reported, differences in the incidence of perioperative stroke among various surgical procedures have not been determined. The purpose of this retrospective analysis was to investigate the incidence of perioperative stroke during hospitalization in patients undergoing elective spinal surgery, and to examine whether the incidence varied according to the surgical procedure. METHODS: A retrospective analysis of data from the Diagnosis Procedure Combination database, a nationwide administrative impatient database in Japan, identified 167,106 patients who underwent elective spinal surgery during 2007-2012. Patient information extracted included age, sex, preoperative comorbidity, administration of blood transfusion, length of hospitalization, and type of hospital. Clinical outcomes included perioperative stroke during hospitalization, and in-hospital death. RESULTS: The overall incidence of perioperative stroke was 0.22 % (371/167,106) during hospitalization. A logistic regression model fitted with a generalized estimating equation showed perioperative stroke was associated with advanced age, a history of cardiac disease, an academic institution, and resection of a spinal tumor. Patients who underwent resection of a spinal cord tumor (reference) had a higher risk of stroke compared with those undergoing discectomy (odds ratio (OR), 0.29; 95 % confidence interval (CI), 0.14-0.58; p = 0.001), decompression surgery (OR, 0.44; 95 % CI, 0.26-0.73; p = 0.001), or arthrodesis surgery (OR, 0.55; 95 % CI, 0.34-0.90); p = 0.02). Advanced age (≥80 years; OR, 5.66; 95 % CI, 3.10-10.34; p ≤ 0.001), history of cardiac disease (OR, 1.58; 95 % CI, 1.10-2.26; p = 0.01), diabetes (OR, 1.73; 95 % CI, 1.36-2.20; p ≤ 0.001), hypertension (OR, 1.53; 95 % CI, 1.18-1.98; p = 0.001), cervical spine surgery (OR, 1.44; 95 % CI, 1.09-1.90; p = 0.01), a teaching hospital (OR, 1.36; 95 % CI, 1.01-1.82; p = 0.04), and length of stay (OR, 1.008; 95 % CI, 1.005-1.010; p ≤ 0.001) were also risk factors for perioperative stroke. CONCLUSIONS: Perioperative stroke occurred in 0.22 % of patients undergoing spinal surgery. Resection of a spinal cord tumor was associated with increased risk of perioperative stroke as well as advanced age, comorbidities at admission, cervical spine surgery, surgery in a teaching hospital, and length of stay.

Patient satisfaction with double-door laminoplasty for cervical compression myelopathy.

BACKGROUND: Patient satisfaction with posterior laminoplasty for cervical compression myelopathy is not yet established. Moreover, postoperative patient-reported outcomes (PROs) associated with patient satisfaction remain unclear. This study aimed to investigate patient satisfaction after double-door laminoplasty for cervical compression myelopathy, and to identify the postoperative patient-reported outcomes associated with patient satisfaction. METHODS: This retrospective study included 97 patients with cervical compression myelopathy who underwent double-door laminoplasty between 2002 and 2010 in our institution [mean follow-up: 58 months (range 12-123 months)]. We assessed postoperative PROs from questionnaires administered before surgery and at the latest follow-up. These questionnaires included the Neck Disability Index, physical and mental component summary of Short Form-36, EuroQol-5 dimension, Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and a numerical rating scale of pain or numbness in the neck, arms, and scapular lesion. Satisfaction was evaluated on the basis of a seven-point scale. Patients were divided into two groups: satisfied (very satisfied, satisfied, slightly satisfied) and dissatisfied (neither satisfied nor dissatisfied, slightly dissatisfied, dissatisfied, very dissatisfied). All PROs and the effectiveness of surgical treatment assessed by JOACMEQ were compared between both groups. RESULTS: The satisfied group comprised 69 patients (71 %). Univariate analysis revealed a significant difference in scapular pain, Neck Disability Index, physical component summary of Short Form-36, postoperative mental component summary of Short Form-36, and improvement of lower extremity function postoperatively between both groups. Multivariate analysis revealed that there was a significantly higher proportion of patients with improved lower extremity function in the satisfied group than in the dissatisfied group. CONCLUSIONS: In conclusion, 71 % of the patients who underwent double-door laminoplasty for cervical compression myelopathy were satisfied. The findings of this study, which examines the association between patient satisfaction and PROs, suggest that improvement in lower extremity function following surgical intervention affects patient satisfaction in those with cervical compression myelopathy.

Cervical canal stenosis caused by progressive fusion and enlargement of cervical vertebrae with features of Proteus syndrome and Klippel-Feil syndrome.

We report the case of a female who presented with progressive fusion and an enlargement of the cervical vertebrae. Her cervical deformity gradually progressed with age, and the abnormal bony protrusion into the spinal canal caused myelopathy. We resected the affected vertebrae to decompress the spinal cord and performed combined anterior-posterior spinal fusion. The progression of the spinal deformity and enlargement of vertebrae stopped after surgery. The enlargement of vertebrae in the present case resembled that observed in Proteus syndrome; however, autonomous vertebral fusion has not been reported previously in patients with this condition. Our report may help expand the knowledge on developmental spine disorders.

Two-year results of single-level fixation with lateral mass screws for cervical degenerative spondylolisthesis: patient series.

BACKGROUND: In surgery for cervical spondylotic myelopathy (CSM) with spondylolisthesis, there is no consensus on the correction and fixation for spondylolisthesis. The authors retrospectively studied whether the correction of single-level fixation with lateral mass screws (LMSs) could be maintained. OBSERVATIONS: The records of patients with CSM with spondylolisthesis who had been treated with posterior decompression and single-level fusion with LMSs from 2017 to 2021 were retrospectively reviewed. Radiographic measurements included cervical parameters such as C2-7 lordosis, T1 slope, and the degree of spondylolisthesis (percent slippage) before surgery, immediately after surgery, and at the final observation. Ten cases (mean age 72.8 ± 7.8 years) were included in the final analysis, and four cases (40%) were on hemodialysis. The median observation period was 26.5 months (interquartile range, 12-35.75). The mean percent slippage was 16.8% ± 4.7% before surgery, 5.3% ± 4.0% immediately after surgery, and 6.5% ± 4.7% at the final observation. Spearman's rank correlation showed a moderate correlation between preoperative slippage magnitude and correction loss (r = 0.659; p = 0.038). Other parameters showed no correlation with correction loss. LESSONS: For CSM with spondylolisthesis, single-level fixation with LMSs achieved and maintained successful correction in the 2-year observation.

Association Between Paravertebral Muscle Mass and Improvement in Sagittal Imbalance After Decompression Surgery of Lumbar Spinal Stenosis.

STUDY DESIGN: Retrospective observational study. OBJECTIVE: This study examined associated factors for the improvement in spinal imbalance following decompression surgery without fusion. SUMMARY OF BACKGROUND DATA: Several reports have suggested that decompression surgery without fusion may have a beneficial effect on sagittal balance in patients with lumbar spinal stenosis (LSS) through their postoperative course. However, few reports have examined the association between an improvement in sagittal imbalance and spinal sarcopenia. METHODS: We retrospectively reviewed 92 patients with LSS and a preoperative sagittal vertical axis (SVA) more than or equal to 40 mm who underwent decompression surgery without fusion at a single institution between April 2017 and October 2018. Patients' background and radiograph parameters and the status of spinal sarcopenia, defined using the relative cross-sectional area (rCSA) of the paravertebral muscle (PVM) and psoas muscle at the L4 caudal endplate level, were assessed. We divided the patients into two groups: those with a postoperative SVA less than 40 mm (balanced group) and those with a postoperative SVA more than or equal to 40 mm (imbalanced group). We then compared the variables between the two groups. RESULTS: A total of 29 (31.5%) patients obtained an improved sagittal imbalance after decompression surgery. The rCSA-PVM in the balanced group was significantly higher than that in the imbalanced group (P = 0.042). The preoperative pelvic incidence (PI)-lumbar lordosis (LL) mismatch (P = 0.048) and the proportion with compression vertebral fracture (P = 0.028) in the balanced group were significantly lower than those in the imbalanced group. A multivariate logistic regression analysis identified PI-LL less than or equal to 10° and rCSA-PVM more than or equal to 2.5 as significant associated factor for the improvement in spinal imbalance following decompression surgery. CONCLUSION: A larger volume of paravertebral muscles and a lower PI-LL were associated with an improvement in sagittal balance in patients with LSS who underwent decompression surgery.Level of Evidence: 3.

The standing T1-L1 pelvic angle: a useful radiographic predictor of proximal junctional kyphosis in adult spinal deformity.

OBJECTIVE: Proximal junctional kyphosis (PJK), which can worsen a patient's quality of life, is a common complication following the surgical treatment of adult spinal deformity (ASD). Although various radiographic parameters have been proposed to predict the occurrence of PJK, the optimal method has not been established. The present study aimed to investigate the usefulness of the T1-L1 pelvic angle in the standing position (standing TLPA) for predicting the occurrence of PJK. METHODS: The authors retrospectively extracted data for patients with ASD who underwent minimum 5-level fusion to the pelvis with upper instrumented vertebra between T8 and L1. In the present study, PJK was defined as ≥ 10° progression of the proximal junctional angle or reoperation due to progressive kyphosis during 1 year of follow-up. The following parameters were analyzed on whole-spine standing radiographs: the T1-pelvic angle, conventional thoracic kyphosis (TK; T4-12), whole-thoracic TK (T1-12), and the standing TLPA (defined as the angle formed by lines extending from the center of T1 and L1 to the femoral head axis). A logistic regression analysis and a receiver operating characteristic curve analysis were performed. RESULTS: A total of 50 patients with ASD were enrolled (84% female; mean age 74.4 years). PJK occurred in 19 (38%) patients. Preoperatively, the PJK group showed significantly greater T1-pelvic angle (49.2° vs 34.4°), conventional TK (26.6° vs 17.6°), and standing-TLPA (30.0° vs 14.9°) values in comparison to the non-PJK group. There was no significant difference in the whole-thoracic TK between the two groups. A multivariate analysis showed that the standing TLPA and whole-thoracic TK were independent predictors of PJK. The standing TLPA had better accuracy than whole-thoracic TK (AUC 0.86 vs 0.64, p = 0.03). The optimal cutoff value of the standing TLPA was 23.0° (sensitivity 0.79, specificity 0.74). Using this cutoff value, the standing TLPA was the best predictor of PJK (OR 8.4, 95% CI 1.8-39, p = 0.007). CONCLUSIONS: The preoperative standing TLPA was more closely associated with the occurrence of PJK than other radiographic parameters. These results suggest that this easily measured parameter is useful for the prediction of PJK.

Factors Associated with Retro-Odontoid Pseudotumor in Long-Term Hemodialysis Patients.

OBJECTIVE: Hemodialysis has been reported to be associated with retro-odontoid pseudotumor (ROP), but its clinical characteristics have not been well described. The purpose of the present study was to investigate the factors associated with ROP in hemodialysis patients. METHODS: A retrospective clinical study of hemodialysis patients was conducted with the evaluation of computed tomography and magnetic resonance imaging of cervical spinal lesions at a single institution from 2012 to 2020. The patients' characteristics and radiographic findings were assessed. A case-control analysis was performed between patients with ROP (ROP group) and patients without ROP (control group). RESULTS: We analyzed 46 patients. The mean duration of hemodialysis (± standard deviation) was 21.5 ± 11.8 years. The mean retro-odontoid soft tissue thickness was 4.3 ± 0.3 mm and was correlated with the duration of hemodialysis (r = 0.46, P < 0.01). Thirty patients (65.2%) were included in the ROP group. The ROP group showed a significantly longer duration of hemodialysis (24.9 ± 11.2 years vs. 15.2 ± 10.3 years, P < 0.01) and a higher incidence of osteolytic lesions in the atlantoaxial joint compared with the control group (60.0% vs. 18.8%, P < 0.01). Logistic regression analysis revealed the atlantoaxial osteolytic lesions are associated with retro-odontoid pseudotumor in hemodialysis patients (odds ratio, 5.1; 95% confidence interval, 1.1-24.2; P = 0.04). CONCLUSIONS: The existence of ROP in hemodialysis patients was associated with osteolytic lesions in the atlantoaxial joint. The finding of atlantoaxial erosive lesions in long-term hemodialysis patients requires spine surgeons to carefully evaluate the presence of ROP.

Dynamization-Posterior Lumbar Interbody Fusion for Hemodialysis-Related Spondyloarthropathy: Evaluation of the Radiographic Outcomes and Reoperation Rate within 2 Years Postoperatively.

STUDY DESIGN: Clinical case series. PURPOSE: This study aimed to report dynamization-posterior lumbar interbody fusion (PLIF), our surgical treatment for hemodialysisrelated spondyloarthropathy (HSA), and investigate patients' postoperative course within 2 years. OVERVIEW OF LITERATURE: HSA often requires lumbar fusion surgery. Conventional PLIF for HSA may cause progressive destructive changes in the vertebral endplate, leading to progressive cage subsidence, pedicle screw loosening, and pseudoarthrosis. A dynamic stabilization system might be effective in patients with a poor bone quality. Thus, we performed "dynamization-PLIF" in hemodialysis patients with destructive vertebral endplate changes. METHODS: We retrospectively examined patients with HSA who underwent dynamization-PLIF at our hospital between April 2010 and March 2018. The radiographic measurements included lumbar lordosis and local lordosis in the fused segment. The evaluation points were before surgery, immediately after surgery, 1 year after surgery, and 2 years after surgery. The preoperative and postoperative radiographic findings were compared using a paired t-test. A p-value of less than 0.05 was considered significant. RESULTS: We included 50 patients (28 males, 22 females). Lumbar lordosis and local lordosis were significantly improved through dynamization- PLIF (lumbar lordosis, 28.4°-35.5°; local lordosis, 2.7°-12.8°; p<0.01). The mean local lordosis was maintained throughout the postoperative course at 1- and 2-year follow-up (12.9°-12.8°, p=0.89 and 12.9°-11.8°, p=0.07, respectively). Solid fusion was achieved in 59 (89%) of 66 fused segments. Solid fusion of all fixed segments was achieved in 42 cases (84%). Within 2 years postoperatively, only six cases (12%) were reoperated (two, surgical debridement for surgical site infection; two, reoperation for pedicle screw loosening; one, laminectomy for epidural hematoma; one, additional fusion for adjacent segment disease). CONCLUSIONS: Dynamization-PLIF showed local lordosis improvement, a high solid fusion rate, and a low reoperation rate within 2 years of follow-up.

Medialization of Common Carotid Artery Is Associated with Cervical Kyphosis.

INTRODUCTION: Reportedly, the medialization of the common carotid artery (MCCA) to be a vascular anomaly with a potential risk of intraoperative carotid artery injury. Nevertheless, among spine surgeons, the presence of MCCA has not been well recognized. METHODS: We retrospectively reviewed consecutive patients who underwent cervical radiographs and magnetic resonance imaging (MRI) examinations in a single spine center. Using MRI, the MCCA grade was classified into grades 1 to 3 in order of severity. Radiographic measurement included C2-C7 angles as cervical lordosis, cervical sagittal vertical axis (C-SVA), T1 slope (T1S), and T1S-cervical lordosis mismatch. We compared each patient's background and radiographic parameters between patients with each of the three MCCA grades. The continuous variables were compared using the Jonckheere-Terpstra trend test and the proportions were compared using the Cochran-Armitage trend test to investigate the trend of variables in three grades. RESULTS: The present study included data from 133 eligible patients (65 males and 68 females) with a mean age of 63.7 (±14.2) years. The details of MCCA grading were as follows: grade 1, n=101; grade 2, n=27; and grade 3, n=5. With an increasing MCCA grade, age (61.9±14.0, 68.2±13.8, and 76.4±9.4 years for grades 1, 2, and 3, respectively, p=0.005) and proportion of female (p<0.001) had an increasing trend, whereas cervical lordosis had a decreasing trend (11.7±13.5°, 7.0±14.5°, and -10.0±19.2° for grades 1, 2, and 3, respectively, p=0.011). CONCLUSIONS: Several patient backgrounds including the female gender, older age, and kyphotic alignment were determined as MCCA risk factors. Careful preoperative neck vasculature assessment would avoid a catastrophic complication during anterior cervical surgery.

Surgical treatment for cervical spine injury in nonagenarians: A report of three cases.

Among the elderly, even minor injuries can cause cervical spine fractures. With the increasing number of nonagenarians, the opportunities for treatment of cervical spine injuries in nonagenarians are getting to be more common. Conservative therapy is often chosen in nonagenarians with cervical spine injuries because of high risk associated with surgical treatment; however, we present herein the cases of three patients in nonagenarians who underwent surgical treatment for cervical spine injury. After a fall, three cases of nonagenarians who lived alone and independent were diagnosed with a Jefferson fracture and minor dislocated type II odontoid fracture, a C4 fracture with diffuse idiopathic skeletal hyperostosis, and a fracture-dislocation of C2, respectively. Their past medical history included several diseases, but we decided that spine surgery under general anesthesia was acceptable based on their pre-injury condition. We performed posterior fixation for all cases. As a result, while two patients developed postoperative minor complications, all cases showed favorable postoperative courses. They acquired independent or partially assisted walking and were transferred to the hospital for rehabilitation. If fundamental activity of daily living and general condition permit, posterior fixation seems to be a good choice even in nonagenarians.