Restoring the ideal Roussouly sagittal alignment in Lenke 5 adolescent idiopathic scoliosis patients: a method for decreasing the risk of proximal junctional kyphosis.

PURPOSE: Although the Roussouly classification has been widely used in surgical planning for adult scoliosis patients, little is known about whether it can be used to guide sagittal correction for adolescent idiopathic scoliosis (AIS) patients. The purpose of this study was to explore whether the Roussouly classification could be used to help surgeons restore the ideal sagittal alignment for AIS patients to avoid the development of proximal junctional kyphosis (PJK). METHODS: In this retrospective cohort study, eighty-seven patients with Lenke 5 AIS who underwent surgery from January 2010 to August 2020 were enrolled and divided into two groups: the PJK group and the non-PJK group. All patients were classified into "current types" and "ideal types" according to two versions of the Roussouly classification, and the mismatch rate was evaluated in terms of the consistency between their current type and ideal type. Student's t test, Mann‒Whitney U test, Pearson's Chi-square test, and others were used to compare the two groups regarding patient demographic characteristics (age, sex, Risser sign, etc.) and radiographic parameters (sagittal vertical axis [SVA]; thoracic kyphosis [TK]; thoracolumbar junctional kyphosis [TLK]; lumbar lordosis [LL]; pelvic incidence [PI]; pelvic tilt [PT]; sacral slope [SS]; upper instrumented vertebra [UIV]; lower instrumented vertebra [LIV]; etc.). Multivariate logistic regression with backwards stepwise selection was performed to identify the risk factors for PJK. RESULTS: PJK was observed in 16 out of 87 patients (18.4%) until the final follow-up. The incidence of PJK was significantly higher in the patients not matching their ideal type than in those who did after surgery (60.9% vs. 3.1%, p = 0.000). The patients with ideal Type 1 had the highest incidence of PJK, while the lowest incidence was observed in patients with ideal Type 2 (50.0% vs. 5.1%, p = 0.000). The PJK group had greater TK, LL, and PI-LL than the non-PJK group before and after surgery. The postoperative PJA in the PJK group was also larger than that in the non-PJK group. Multivariate logistic regression revealed that postoperative Roussouly type mismatch was significantly associated with the occurrence of PJK (OR = 64.2, CI = 9.6-407.1, p = 0.000). CONCLUSIONS: The Roussouly classification could serve as a prognostic tool for PJK in Lenke 5 AIS patients. Corrective surgery should restore sagittal alignment with respect to the patient's ideal sagittal profile (according to the Roussouly classification based on the PI) to decrease the incidence of PJK in AIS patients.

Preoperative Skull Traction, Anterior Debridement, Bone Grafting, and Internal Fixation for Cervical Tuberculosis with Severe Kyphosis.

OBJECTIVE: Cervical tuberculosis (CTB) readily causes local kyphosis, and its surgical strategy remains controversial. Although some previous studies suggested that the anterior approach could effectively treat CTB, patients in these studies only suffered mild to moderate kyphosis. Therefore, little is known about whether the anterior approach can achieve satisfactory outcomes in CTB patients with severe kyphosis. This study was performed to evaluate the safety and efficacy of preoperative skull traction combined with anterior surgery for the treatment of CTB patients with a severe kyphosis angle of more than 35°. METHODS: In this retrospective study, we enrolled 31 CTB patients with severe kyphosis who underwent preoperative skull traction combined with anterior surgery from April 2015 to January 2021. Patients were followed up for at least 2 years. Clinical data, such as operative time, blood loss, and postoperative hospital stay, were collected. The clinical outcomes included American Spinal Injury Association (ASIA) spinal cord injury grade, Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score, and related complications. The radiological outcomes included the Cobb angle of cervical kyphosis at each time point and the bony fusion state. Clinical efficacy was evaluated by paired Student's t-test, Mann-Whitney U-test, and others. RESULTS: Six patients had involvement of one vertebra, 21 had involvement of two vertebrae, and four had involvement of three vertebrae. The most common level of vertebral involvement was C4-5, whereas the most common apical vertebra of kyphosis was C4. The mean kyphosis angle was 46.1° ± 7.7° preoperatively, and the flexibility on dynamic extension-flexion X-rays and cervical MRI was 17.5% ± 7.8% and 43.6% ± 11.0%, respectively (p = 0.000). The kyphosis angle significantly decreased to 13.2° ± 3.2° after skull traction, and it further corrected to -6.1° ± 4.3° after surgery, which was well maintained at the final follow-up with a mean Cobb angle of -5.4° ± 3.9°. The VAS and JOA scores showed significant improvement after surgery. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels normalized at 3 months after surgery. All patients achieved solid bone fusion, and no complications related to the instrumentation or recurrence were observed. CONCLUSION: Preoperative skull traction combined with anterior debridement, autologous iliac bone grafting, and internal plate fixation can be an effective and safe surgical method for the treatment of cervical tuberculosis with severe kyphosis. Skull traction can improve the safety and success rate of subsequent anterior corrective surgery.

Characteristics of Sagittal Alignment in Patients with Severe and Rigid Scoliosis.

OBJECTIVE: There has been increasing concern about the importance of sagittal alignment in the evaluation and treatment of spinal scoliosis. However, recent studies have only focused on patients with mild to moderate scoliosis. To date, little is known about the sagittal alignment in patients with severe and rigid scoliosis (SRS). This study was performed to evaluate the sagittal alignment in patients with SRS, and to analyze how it was altered after corrective surgery. METHODS: In this retrospective cohort study, we included 58 patients with SRS who underwent surgery from January 2015 to April 2020. Preoperative and postoperative radiographs were reviewed, and the sagittal parameters mainly included thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacrum slope (SS), and sagittal vertical axis (SVA). The sagittal balance state was evaluated according to whether the PI minus the LL (PI-LL) was less than 9°, and the patients were divided into thoracic hyperkyphosis and normal groups based on whether the TK exceeded 40°. The Student's t test, Pearson's test, and Receiver operating characteristic (ROC) curve analysis were used to compare related parameters between the different groups. RESULTS: The mean follow-up duration was 2.8 years. Preoperatively, the mean PI was 43.6 ± 9.4°, and the mean LL was 65.2 ± 13.9°. Sixty-nine percent of patients showed sagittal imbalance, and they showed larger TK and LL values and smaller PI and SVA values than those with sagittal balance. Additionally, most patients (44/58) presented with thoracic hyperkyphosis; this group had smaller PI and SVA values than the normal patients. Patients with syringomyelia-associated scoliosis were more likely to present with thoracic hyperkyphosis. The TK and LL values were significantly decreased, and 45% of patients with preoperative sagittal imbalance recovered after surgery. These patients had a larger PI (46.4 ± 9.0° vs 38.3 ± 8.8°, P = 0.003) and a smaller TK (25.5 ± 5.2° vs 36.3 ± 8.0°, P = 0.000) at the final follow-up. CONCLUSION: Preoperative sagittal imbalance appears in the majority of SRS patients, accounting for approximately 69% of our cohort. Patients with small PI values or syringomyelia-associated scoliosis were more likely to present with thoracic hyperkyphosis. Sagittal imbalance can generally be corrected by surgery, except in patients with a PI less than 39°. To achieve good postoperative sagittal alignment, we recommend controlling the TK to within 31°.

Comparison of Long-Term Clinical and Radiographical Outcomes between the Anterior and Combined Anterior and Posterior Approaches for Treating Lumbosacral Tuberculosis.

OBJECTIVE: Both anterior and combined anterior and posterior approaches have been used to treat lumbosacral tuberculosis. However, long-term follow-up studies of each approach have not been conducted. We aimed to compare the long-term clinical and radiographical outcomes between the two approaches. METHODS: In this retrospective cohort study, we included 49 patients with a minimum 6-year follow-up between January 2008 and March 2012. Twenty-four patients underwent the anterior approach (anterior group), and 25 underwent the combined anterior and posterior approach (anterior-posterior group). Student's t test, Mann-Whitney U test, and Pearson's chi-square test were used to compare the two groups regarding clinical data, such as visual analogue scale scores, Oswestry disability index scores and neurological status, and radiographical data, such as lumbosacral angle, lumbar lordosis, and L5-S1 height. Furthermore, operative time, length of stay, and intraoperative and postoperative blood loss (IBL, PBL) were recorded. RESULTS: Both groups had satisfactory clinical and radiographical outcomes until the final follow-up. All patients achieved bony fusion, and no group differences were found in any of the clinical indices. Both groups corrected and maintained the lumbosacral angle, lumbar lordosis, and L5-S1 height. However, the operative time, length of stay, maximum Hb drop, IBL, and PBL of the anterior group (140.63 ± 24.73 min, 12.58 ± 2.45 days, 28.33 ± 9.70 g/L, 257.08 ± 110.47 ml, and 430.60 ± 158.27 ml, respectively) were significantly lower than those of the anterior-posterior group (423.60 ± 82.81 min, P < 0.001; 21.32 ± 3.40 days, P < 0.001; 38.48 ± 8.03 g/L, P < 0.001; 571.60 ± 111.04 ml, P < 0.001; and 907.01 ± 231.99 ml, P < 0.001). CONCLUSION: This retrospective study demonstrated long-term efficacy of the anterior approach with a single screw fixation, which was as effective as that of the combined anterior and posterior approach, with the advantage of less trauma.

Incidence and Risk Factors for Postoperative Ileus after Posterior Surgery in Adolescent Idiopathic Scoliosis.

OBJECTIVE: Postoperative ileus (POI) is a relatively common complication after spinal fusion surgery, which can lead to delayed recovery, prolonged length of stay and increased medical costs. However, little is known about the incidence and risk factors of POI after corrective surgery for patients with adolescent idiopathic scoliosis (AIS). This study was performed to report the incidence of POI and identify the independent risk factors for POI after postoperative corrective surgery. METHODS: In this retrospective cohort study, A total of 318 patients with AIS who underwent corrective surgery from April 2015 to February 2021 were enrolled and divided into two groups: those with POI and those without POI. The Student's t test, Mann-Whitney U test, and Pearson's chi-square test were used to compare the two groups regarding patient demographics and preoperative characteristics (age, sex and the major curve type), intraoperative and postoperative parameters (lowest instrumented vertebra [LIV], number of screws, and length of stay), radiographic parameters (T5-12 thoracic kyphosis [TK], T10-L2 thoracolumbar kyphosis and height [TLK and T10-L2 height], L1-S1 lumbar lordosis [LL], and L1-5 height). Then, a multivariate logistic regression analysis was used to identify independent risk factors for POI, and a receiver operating characteristic (ROC) curve was performed to assess the predictive values of these risk factors. RESULTS: Forty-two (13.2%) of 318 patients who developed POI following corrective surgery were identified. The group with POI had a significantly longer length of stay, more lumbar screws, higher proportions of a major lumbar curve and lumbar anterior screw breech, and a lower LIV. Among radiographic parameters, the mean lumbar Cobb angle at baseline, the changes in the lumbar Cobb angle, and T10-L2 and L1-5 height from before to after surgery were significantly larger in the group with POI than in the group without POI. Multivariate logistic regression analysis showed that large changes in T10-L2 (odds ratio [OR] =2.846, P = 0.007) and L1-5 height (OR = 31.294, p = 0.000) and lumbar anterior screw breech (OR = 5.561, P = 0.006) were independent risk factors for POI. The cutoff values for the changes in T10-L2 and L1-5 height were 1.885 cm and 1.195 cm, respectively. CONCLUSION: In this study, we identified that large changes in T10-L2 and L1-5 height and lumbar anterior screw breech were independent risk factors for POI after corrective surgery. Improving the accuracy of pedicle screw placement might reduce the incidence of POI, and greater attention should be given to patients who are likely to have large changes in T10-L2 and L1-5 height after corrective surgery.

Comparison of Long-Term Outcomes between the n-HA/PA66 Cage and the PEEK Cage Used in Transforaminal Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Matched-Pair Case Control Study.

OBJECTIVE: The nanohydroxyapatite/polyamide-66 (n-HA/PA66) cage is a novel bioactive nonmetal cage that is now used in some medical centers, while the polyetheretherketone (PEEK) cage is a typical device that has been widely used for decades with excellent clinical outcomes. This study was performed to compare the long-term radiographic and clinical outcomes of these two different cages used in transforaminal lumbar interbody fusion (TLIF). METHODS: In this retrospective and matched-pair case control study, we included 200 patients who underwent TLIF from January 2010 to December 2014 with a minimum 7-year follow-up. One hundred patients who used n-HA/PA66 cages were matched with 100 patients who used PEEK cages for age, sex, diagnosis, and fusion level. The independent student's t-test and Pearson's chi-square test were used to compare the two groups regarding radiographic (fusion status, cage subsidence rate, segmental angle [SA], and interbody space height [IH]) and clinical (Oswestry Disability Index [ODI], and Visual Analog Scale [VAS] for back and leg) parameters preoperatively, postoperatively, and at the final follow-up. RESULTS: The n-HA/PA66 and PEEK groups had similar fusion rates of bone inside and outside the cage at the final follow-up (95.3% vs 91.8%, p = 0.181, 92.4% vs 90.1%, p = 0.435). The cage union ratios exposed to the upper and lower endplates of the n-HA/PA66 group were significantly larger than those of the PEEK group (p < 0.05). The respective cage subsidence rates in the n-HA/PA66 and PEEK groups were 10.5% and 17.5% (p = 0.059). There were no significant differences between the two groups in the SA, IH, ODI scores, or VAS scores at any time point. The n-HA/PA66 group showed high fusion and low subsidence rates during long-term follow-up. CONCLUSION: Both n-HA/PA66 and PEEK cages can achieve satisfactory long-term clinical and radiographic outcomes in TLIF. However, the n-HA/PA66 group showed significantly larger cage union ratios than the PEEK group. Therefore, the results indicated that the n-HA/PA66 cage is an ideal alternative material comparable to the PEEK cage in TLIF.

Stepwise reduction of bone mineral density increases the risk of cage subsidence in oblique lumbar interbody fusion patients biomechanically: an in-silico study.

BACKGROUND: Cage subsidence causes poor prognoses in patients treated by oblique lumbar interbody fusion (OLIF). Deterioration of the biomechanical environment initially triggers cage subsidence, and patients with low bone mineral density (BMD) suffer a higher risk of cage subsidence. However, whether low BMD increases the risk of cage subsidence by deteriorating the local biomechanical environment has not been clearly identified. METHODS: OLIF without additional fixation (stand-alone, S-A) and with different additional fixation devices (AFDs), including anterolateral single rod screws (ALSRs) and bilateral pedicle screws (BPSs) fixation, was simulated in the L4-L5 segment of a well-validated finite element model. The biomechanical effects of different BMDs were investigated by adjusting the material properties of bony structures. Biomechanical indicators related to cage subsidence were computed and recorded under different directional moments. RESULTS: Overall, low BMD triggers stress concentration in surgical segment, the highest equivalent stress can be observed in osteoporosis models under most loading conditions. Compared with the flexion-extension loading condition, this variation tendency was more pronounced under bending and rotation loading conditions. In addition, AFDs obviously reduced the stress concentration on both bony endplates and the OLIF cage, and the maximum stress on ALSRs was evidently higher than that on BPSs under almost all loading conditions. CONCLUSIONS: Stepwise reduction of BMD increases the risk of a poor local biomechanical environment in OLIF patients, and regular anti-osteoporosis therapy should be considered an effective method to biomechanically optimize the prognosis of OLIF patients.

Transplantation of NEP1-40 and NT-3 Gene-Co-Transduced Neural Stem Cells Improves Function and Neurogenesis after Spinal Cord Injury in a Rat Model.

Background: Spinal cord injury (SCI) generally results in necrosis, scarring, cavitation, and a release of inhibitory molecules of the nervous system, which lead to disruption of neurotransmission and impede nerve fiber regeneration. This study was intended to evaluate the therapeutic efficacy rates of the transplantation of NEP1-40- and NT-3 gene-co-transduced neural stem cells (NSCs) in a rat model of SCI. Methods: Ninety Sprague-Dawley rats were subdivided randomly into six groups: sham-operated, SCI model, SCI + NSCs-NC, SCI + NEP1-40-NSCs, SCI + NT-3-NSCs, and SCI + NEP1-40/NT-3-NSCs. Motor function at different time points was evaluated using the Basso, Beattie, and Bresnahan locomotor activity scoring system (BBB). At 8 weeks post-transplantation, histological analysis, a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, immunofluorescent assay, immunocytochemical staining, and cholera toxin subunit B (CTB) retrograde tracing were performed. Results: BBB scores of the co-transduction group significantly surpassed those of other transplantation groups and of the SCI-model group after 2 weeks post-transplantation. The apoptotic rate of neurocytes was significantly lower in the co-transduction group than in other experimental groups. Expression of NF-200, MBP, and ChAT was significantly higher in the SCI + NEP1-40/NT-3-NSCs group than in other transplantation groups, whereas the expression of GFAP and GAD67 was the second lowest after the sham-operated group. CTB retrograde tracing showed that CTB-positive neural fibers on the caudal side of the hemisected site were more numerous in the SCI + NEP1-40/NT-3-NSCs group than in other experimental groups. Conclusion: Transplantation of NEP1-40- and NT-3-gene-co-transduced NSCs can modify the protein expression following acute SCI and promote neuron formation and axonal regeneration, thus having a neuroprotective effect. Furthermore, this effect surpasses that of transplantation of single-gene-transduced NSCs. Transplantation of NEP1-40- and NT-3-gene-co-transduced NSCs is effective at the neural recovery of the rat model of SCI and may be a novel strategy for clinical treatment of SCI.

Deterioration of the fixation segment's stress distribution and the strength reduction of screw holding position together cause screw loosening in ALSR fixed OLIF patients with poor BMD.

The vertebral body's Hounsfield unit (HU) value can credibly reflect patients' bone mineral density (BMD). Given that poor bone-screw integration initially triggers screw loosening and regional differences in BMD and strength in the vertebral body exist, HU in screw holding planes should better predict screw loosening. According to the stress shielding effect, the stress distribution changes in the fixation segment with BMD reduction should be related to screw loosening, but this has not been identified. We retrospectively collected the radiographic and demographic data of 56 patients treated by single-level oblique lumbar interbody fusion (OLIF) with anterior lateral single rod (ALSR) screw fixation. BMD was identified by measuring HU values in vertebral bodies and screw holding planes. Regression analyses identified independent risk factors for cranial and caudal screw loosening separately. Meanwhile, OLIF with ALSR fixation was numerically simulated; the elastic modulus of bony structures was adjusted to simulate different grades of BMD reduction. Stress distribution changes were judged by computing stress distribution in screws, bone-screw interfaces, and cancellous bones in the fixation segment. The results showed that HU reduction in vertebral bodies and screw holding planes were independent risk factors for screw loosening. The predictive performance of screw holding plane HU is better than the mean HU of vertebral bodies. Cranial screws suffer a higher risk of screw loosening, but HU was not significantly different between cranial and caudal sides. The poor BMD led to stress concentrations on both the screw and bone-screw interfaces. Biomechanical deterioration was more severe in the cranial screws than in the caudal screws. Additionally, lower stress can also be observed in fixation segments' cancellous bone. Therefore, a higher proportion of ALSR load transmission triggers stress concentration on the screw and bone-screw interfaces in patients with poor BMD. This, together with decreased bony strength in the screw holding position, contributes to screw loosening in osteoporotic patients biomechanically. The trajectory optimization of ALSR screws based on preoperative HU measurement and regular anti-osteoporosis therapy may effectively reduce the risk of screw loosening.

The Mismatch Between Bony Endplates and Grafted Bone Increases Screw Loosening Risk for OLIF Patients With ALSR Fixation Biomechanically.

The mismatch between bony endplates (BEPs) and grafted bone (GB) triggers several complications biomechanically. However, no published study has identified whether this factor increases the risk of screw loosening by deteriorating the local stress levels. This study aimed to illustrate the biomechanical effects of the mismatch between BEP and GB and the related risk of screw loosening. In this study, radiographic and demographic data of 56 patients treated by single segment oblique lumbar interbody fusion (OLIF) with anterior lateral single rod (ALSR) fixation were collected retrospectively, and the match sufficiency between BEP and GB was measured and presented as the grafted bony occupancy rate (GBOR). Data in patients with and without screw loosening were compared; regression analyses identified independent risk factors. OLIF with different GBORs was simulated in a previously constructed and validated lumbosacral model, and biomechanical indicators related to screw loosening were computed in surgical models. The radiographic review and numerical simulations showed that the coronal plane's GBOR was significantly lower in screw loosening patients both in the cranial and caudal vertebral bodies; the decrease in the coronal plane's GBOR has been proven to be an independent risk factor for screw loosening. In addition, numerical mechanical simulations showed that the poor match between BEP and GB will lead to stress concentration on both screws and bone-screw interfaces. Therefore, we can conclude that the mismatch between the BEP and GB will increase the risk of screw loosening by deteriorating local stress levels, and the increase in the GBOR by modifying the OLIF cage's design may be an effective method to optimize the patient's prognosis.

Sequential sagittal alignment changes in the cervical spine after occipitocervical fusion.

BACKGROUND: There are few studies regarding sequential changes in the sagittal alignment of the upper and lower cervical regions of the spine after occipitocervical fusion (OCF). In addition, no comparisons of cervical sagittal alignment (CSA) between patients with craniocervical junction disorders (CJDs) and normal populations have been reported. AIM: To compare the CSA of patients with CJDs with that of normal controls and investigate the sequential changes in the CSA of the upper and lower cervical spine after OCF. METHODS: Eighty-four patients who underwent OCF (OCF group) and 42 asymptomatic volunteers (control group) were included. Radiographic parameters, including the occipital to C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa), C2-7 angle (C2-7a), and pharyngeal inlet angle (PIA), were measured and compared pre- and postoperatively. The correlations among the parameters were analyzed using Pearson's correlation test. RESULTS: The O-C2a and PIA of the OCF group were smaller than those of the control group, while their O-EAa and C2-7a values were larger than those of the normal controls. There were no significant differences in O-C2a, C2-7a, or PIA in the OCF group at baseline, 1 mo, or the final follow-up after surgery. The Pearson's correlation results showed that there were significant correlations between the O-C2a and C2Ta, C2-7a, C2-7 sagittal vertical axis (SVA), and PIA at 1 mo after OCF surgery and between O-C2a and O-EAa, C2Ta, C2-7a, C2-7 SVA, and PIA at the final follow-up. CONCLUSION: Patients with CJDs have a more kyphotic upper CSA and a more lordotic lower CSA than normal controls. The effectiveness of OCF surgery in restoring CSA may be limited by the realignment of the craniocervical junction being neglected. The reduction in O-C2a after OCF surgery may increase C2-7a and decrease PIA.

Case report: Thoracolumbar spinal stenosis associated with alkaptonuria.

Background: Alkaptonuria is a rare autosomal genetic disorder with an incidence of about 1 in 1 million per year. Spinal involvement often manifests in the later stages of the disease. However, this is the first report of the presentation of thoracolumbar spinal stenosis. Case presentation: We report the case of a 61-year-old female patient with significant thoracolumbar stenosis symptoms. The patient had obvious kyphosis with preoperative lower extremity muscle strength grade 2/5. Symptoms and imaging signs initially suggested ankylosing spondylitis. This patient was classified into motor incomplete injury (ASIA C). However, the patient was found to have melanin deposits on the sclera and skin, and the urine was darkened at rest. CT and MRI both suggested no bone bridge connection between vertebrae, which was the key difference between ankylosing spondylitis and alkaptonuria in imaging. Most importantly, urine specimen testing and intraoperative pathology demonstrated alkaptonuria. The patient underwent spinal decompression and vertebral body fixation. Postoperative recovery was good: the patient had significantly relieved pain and could stand and walk. Conclusion: This case is the first report of thoracolumbar spinal stenosis associated with alkaptonuria involving the spine.

Clinical algorithm for preventing missed diagnoses of occult cervical spine instability after acute trauma: A case report.

BACKGROUND: Missed or delayed diagnosis of cervical spine instability after acute trauma can have catastrophic consequences for the patient, resulting in severe neurological impairment. Currently, however, there is no consensus on the optimal strategy for diagnosing occult cervical spine instability. Thus, we present a case of occult cervical spine instability and provide a clinical algorithm to aid physicians in diagnosing occult instability of the cervical spine. CASE SUMMARY: A 57-year-old man presented with cervical spine pain and inability to stand following a serious fall from a height of 2 m. No obvious vertebral fracture or dislocation was found at the time on standard lateral X-ray, computed tomography, and magnetic resonance imaging (MRI). Subsequently, the initial surgical plan was unilateral open-door laminoplasty (C3-7) with alternative levels of centerpiece mini-plate fixation (C3, 5, and 7). However, the intraoperative C-arm fluoroscopic X-rays revealed significantly increased intervertebral space at C5-6, indicating instability at this level that was previously unrecognized on preoperative imaging. We finally performed lateral mass fixation and fusion at the C5-6 level. Looking back at the preoperative images, we found that the preoperative T2 MRI showed non-obvious high signal intensity at the C5-6 intervertebral disc and posterior interspinous ligament. CONCLUSION: MRI of cervical spine trauma patients should be carefully reviewed to detect disco-ligamentous injury, which will lead to further cervical spine instability. In patients with highly suspected cervical spine instability indicated on MRI, lateral X-ray under traction or after anesthesia and muscle relaxation needs to be performed to avoid missed diagnoses of occult cervical instability.

Predictive ability of pharyngeal inlet angle for the occurrence of postoperative dysphagia after occipitocervical fusion.

BACKGROUND: PIA has been proven to be a predictor for postoperative dysphagia in patients who undergo occipitospinal fusion. However, its predictive effect for postoperative dysphagia in patients who undergo OCF is unknown. The aim of this study was to evaluate the predictive ability of the pharyngeal inlet angle (PIA) for the occurrence of postoperative dysphagia in patients who undergo occipitocervical fusion (OCF). METHODS: Between 2010 and 2018, 98 patients who had undergone OCF were enrolled and reviewed. Patients were divided into two groups according to the presence of postoperative dysphagia. Radiographic parameters, including the atlas-dens interval (ADI), O-C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa), C2 tilting angle (C2Ta), C2-7 angle (C2-7a), PIA and narrowest oropharyngeal airway space (nPAS), were measured and compared. Simple linear regression and multiple regression analysis were used to evaluate the radiographic predictors for dysphagia. In addition, we used PIA = 90° as a threshold to analyze its effect on predicting dysphagia. RESULTS: Of the 98 patients, 26 exhibited postoperative dysphagia. Preoperatively, PIA in the dysphagia group was significantly higher than that in the nondysphagia group. We detected that O-C2a, O-EAa, PIA and nPAS all decreased sharply in the dysphagia group but increased slightly in the nondysphagia group. The changes were all significant. Through regression analyses, we found that PIA had a similar predictive effect as O-EAa for postoperative dysphagia and changes in nPAS. Additionally, patients with an increasing PIA exhibited no dysphagia, and the sensitivity of PIA <90° in predicting dysphagia reached 88.5%. CONCLUSIONS: PIA could be used as a predictor for postoperative dysphagia in patients undergoing OCF. Adjusting a PIA level higher than the preoperative PIA level could avoid dysphagia. For those who inevitably had decreasing PIA, preserving intraoperative PIA over 90° would help avert postoperative dysphagia. TRIAL REGISTRATION: This trial has been registered in the Medical Ethics Committee of West China Hospital, Sichuan University. The registration number is 762 and the date of registration is Sep. 9 th, 2019.

The effect of multiple-dose oral versus intravenous tranexamic acid in reducing postoperative blood loss and transfusion rate after adolescent scoliosis surgery: a randomized controlled trial.

BACKGROUND CONTEXT: Tranexamic acid (TXA) is widely used in surgery for adolescent idiopathic scoliosis (AIS) and has been proved to be efficacious in reducing intraoperative blood loss (IBL) and the transfusion rate. However, the routine TXA regimen was intraoperative administration alone, in which the concentration of TXA could not cover the whole process of hyperfibrinolysis. And, its ability to control the massive postoperative blood loss (PBL) may be insufficient. Thus, we promoted a multiple-dose regimen of TXA for patients with AIS who underwent surgical correction. PURPOSE: The primary aims were (1) to determine whether the multiple-dose regimen of TXA could reduce PBL and the postoperative transfusion rate, and (2) to compare the efficacy of oral administration with intravenous administration. The secondary aims were (3) to evaluate whether this regimen could alleviate inflammatory response, and (4) to assess the occurrence of drug-related side effects. STUDY DESIGN: Prospective, double-blinded, randomized controlled trial. PATIENT SAMPLE: A total of 108 patients with AIS who underwent posterior scoliosis correction and spinal fusion (PSS) were enrolled in this study. OUTCOME MEASURES: The primary parameters were PBL and postoperative transfusion rate. Other parameters such as total blood loss (TBL), maximum hemoglobin (Hb) decrease, volume of drainage, inflammation markers (interleukin-6 [IL-6] and C-reactive protein [CRP]), and occurrence of complications were also collected and compared. Multiple regression analysis was used to examine the variables that affected PBL. METHODS: Patients were randomized into three groups. All patients received intravenous TXA 50 mg/kg loading dose and 10 mg/kg/h maintenance dose during surgery. Group A received 1 g oral TXA at 4 hours, 10 hours, and 16 hours postoperatively; group B received 0.5 g intravenous TXA at 6 hours, 12 hours, and 18 hours postoperatively; group C received placebo. RESULTS: The mean PBL and postoperative transfusion rate in group A (957.8±378.9 mL, 13.89%) and B (980.3±491.8 mL, 11.11%) were significantly lower than those in group C [1,495.9±449.6 mL, mean differences=538.1 mL, 95% confidence interval (CI), 290.1-786.1 mL, p<0.001; 515.6 mL, 95% CI, 267.6-763.6 mL, p<.001]; (36.11%, p=.029, p=.013). Meanwhile, the mean TBL, maximum Hb decrease, and volume of drainage were also significantly lower in group A and B than in group C. IL-6 and CRP in group A and B were significantly lower than in group C from postoperative days 1 to 3. All these differences were not significant between groups A and B. No drug-related complications were observed in any patient. Multiple regression showed that the application of postoperative TXA and number of screws were significant parameters affecting PBL. CONCLUSIONS: A multiple-dose regimen of TXA, either by oral or intravenous application, could be a safe and effective means of controlling PBL and decreasing the postoperative transfusion rate in patients with AIS who underwent scoliosis surgery. In addition, it could inhibit postoperative inflammatory response.

Loss of Correction After Removal of Spinal Implants in Congenital Scoliosis.

BACKGROUND: Previous studies have reported the progression of deformity in patients with adolescent idiopathic scoliosis after implant removal. However, for patients with congenital scoliosis, few studies have investigated the prognosis after implant removal. METHODS: We observed 24 patients with congenital scoliosis, who underwent implant removal, for at least 3 years. Radiographic parameters and demographic data were compared to evaluate whether implant removal would lead to deformity progression. RESULTS: Four of the 24 patients (16.7%) suffered correction loss and underwent revision surgery (RS). All correction losses occurred within 12 months of implant removal. The average curve of fixed segments (9.84° ± 7.22° to 16.42° ± 16.79°; P = 0.017) and kyphosis of fixed segments (10.46° ± 13.42° to 18.98° ± 25.99°; P = 0.03) increased significantly throughout the follow-up. After excluding patients who underwent RS, the changes in curve of fixed segments (9.10°-11.58°) and kyphosis of fixed segments (8.50°-9.24°) were all within the measurement error. The coronal and sagittal balance maintained during the follow-up. Through comparison, we thought that the younger age and lower Risser's grade with larger scoliosis might be risk factors for correction loss. CONCLUSIONS: Implant removal after fusion surgery for congenital scoliosis may present loss of correction and require RS, thus preserving implants is recommended. When removal of instrumentation is inevitable, parents and patients should be counseled for potential loss of correction and RS, and patients should be monitored for the progression of deformity.

Comparison of long-term clinical and radiographic outcomes between alternative-level and all-level fixation unilateral open-door laminoplasty.

BACKGROUND CONTEXT: Titanium mini-plate has been used in unilateral open-door laminoplasty to maintain the open angle of laminae. Previously, both all-level fixation (C3-C7) and alternative-level (C3, C5, C7) unilateral open-door laminoplasty have been proven to have satisfactory clinical outcomes. However, whether they could achieve similar long-term clinical and radiographic efficacy is still questionable. PURPOSE: To compare the long-term clinical and radiological outcomes between alternative-level and all-level fixation unilateral open-door laminoplasty with a mini-plate fixation system. STUDY DESIGN/SETTING: Retrospective comparative study. PATIENT SAMPLE: Ninety-one patients who underwent unilateral open-door laminoplasty. OUTCOME MEASURES: Clinical results including Japanese Orthopedic Association score, Visual Analogue Score, Neck Dysfunction Index score. Radiographic results including cervical curvature index, cervical range of motion, and the spinal canal expansive parameters, including anteroposterior diameter, Pavlov's ratio, and open angle. METHODS: Between April 2007 and June 2011, 91 patients with minimum 7-year postoperative follow-up were included. Thirty-eight underwent alternative-level fixation (group A) and 53 underwent all-level fixation (group B). Demographic data, including age, gender, operative time, blood loss, and cost, were collected and compared between the two groups. Clinical and radiographic data were obtained preoperatively, at 3 and 6 months and 1 and 3 years postoperatively, as well as at final follow-up. The difference between the two groups and between different time points within one group was compared. RESULTS: Both groups obtained satisfactory clinical outcomes till the final follow-up. No statistic difference was found in Japanese Orthopedic Association, Visual Analogue Score, and Neck Dysfunction Index between the two groups throughout the whole follow-up. Both groups maintained APD and Pavlov's ratio well till follow-up. However, statistic difference was found in the open angle between two groups at final follow-up (34.17±2.75° vs. 36.19±1.80°, p<.05). When we subdivided the cervical segments in group A, we found the mini-plate segments showed maintenance in open angle but a 4.52° decrease in suture segments. The mean cost in group B (17,669.82±1,157.65 $) was significantly higher than in group A (11,452.19±871.07 $; p<.05). CONCLUSIONS: Despite a difference in the maintenance of open angle, both fixation methods achieved satisfactory clinical outcomes. We believe alternative-level fixation is also a safe, effective, and economical fixation method.

Predictive abilities of O-C2a and O-EAa for the development of postoperative dysphagia in patients undergoing occipitocervical fusion.

BACKGROUND CONTEXT: Dysphagia is a common postoperative complication in patients undergoing occipitocervical fusion (OCF). Previous studies had proposed the use of two measures-the occipital to C2 angle (O-C2a) and the occipital and external acoustic meatus to axis angle (O-EAa)-to predict postoperative dysphagia after OCF. However, these studies had small sample sizes and the predictive abilities of both measures are still not clear. PURPOSE: To evaluate the predictive ability of O-EAa and O-C2a for dysphagia after OCF. STUDY DESIGN: A retrospective clinical study. PATIENT SAMPLE: A total of 109 consecutive patients who had undergone OCF. OUTCOME MEASURES: Presence of postoperative dysphagia, O-C2a, C2 tilting angle (C2Ta), O-EAa, and the narrowest oropharyngeal airway space (nPAS). METHODS: Between April 2010 and June 2018, 109 consecutive patients who had undergone OCF were reviewed. Patients were divided into two groups according to the presence of postoperative dysphagia. Radiographic measurements, including O-C2a, C2Ta, O-EAa, and nPAS, were evaluated at preoperative and 1 month postoperative and the findings were compared. Simple linear regression was used to measure the correlations between the parameters and the presence of dysphagia, and the correlations within the parameters. Multiple regression analysis was used to examine the variables that affected the change of nPAS (dnPAS%). Sensitivity and specificity analyses were used to evaluate the effectiveness of the previously proposed measures ("O-C2a change≤-5°" and "postoperative O-EAa<100°") for prediction of post-OCF dysphagia. RESULTS: The incidence of dysphagia after OCF was 26.6% (29/109). Preoperative values for the radiographic parameters were similar between patients with and without dysphagia. In the dysphagia group, both O-C2a and O-EAa values showed a dramatic decrease after surgery, which was accompanied by a decrease in nPAS. Postoperative O-C2a, O-EAa, and nPAS in the dysphagia group were significantly smaller than those in the nondysphagia group (p<.05). The changes in O-EAa, O-C2a, and nPAS showed a linear correlation with the presence of dysphagia (p<.05). In addition, linear correlations were found between two of the three parameters. Multiple regression showed the change of O-C2a and O-EAa were significant predictors for dnPAS% (ß=0.200, p=.022 and ß=0.549, p=.000). The sensitivity and specificity of "O-C2a change≤-5°" in predicting dysphagia were 75.9% and 80.0% respectively, and those of "postoperative O-EAa<100°" were 75.9% and 62.5%, respectively. However, the sensitivity of the combination of these two values in predicting postoperative dysphagia was as high as 96.6%. CONCLUSION: Both O-EAa and O-C2a could be critical predictors for postoperative dysphagia. During surgery, ensuring that the O-EAa exceeds 100° and simultaneously avoiding an O-C2a reduction greater than 5° could effectively avert postoperative dysphagia.

Comparison of two temporary fixation techniques for the treatment of type II odontoid fracture.

To evaluate and compare the clinical and radiographic results between temporary C1-C2 pedicle screw fixation and cable-dragged reduction and cantilever beam internal fixation. Between 2010 and 2013, temporary C1-C2 pedicle screw fixation (Group P, 28 patients) and cable-dragged reduction following cantilever beam internal fixation (Group C, 33 patients) were performed on type II odontoid fracture cases. Implants were removed after fracture union. All of the 61 surgeries were performed successfully with no iatrogenic neurological worsen. One patient in Group P detected intra-operative vertebral artery injury. All patients gained fracture union. Among the observed indexes, only blood loss in Group P (128.9 ± 73.9ml) is statistically higher than in Group C (97.3 ± 5 4.2ml). Pedicle screw fixation carries the risk of vertebral artery injury, especially in patients with high-riding vertebral artery. Cable-dragged reduction following cantilever beam internal fixation could avoid the potential risk of vertebral injury, but it prolonged the fixed segments. We thought cable-dragged reduction following cantilever beam internal fixation could be an alternative method for treating type II odontoid fracture.

Negative pressure pulmonary edema after percutaneous endoscopic interlaminar lumbar discectomy-a case report.

BACKGROUND: Negative pressure pulmonary edema (NPPE) is a rare complication that is more prevalent in young patients. NPPE usually results from acute upper airway obstruction, which is most commonly caused by laryngospasm during extubation. NPPE is characterized by the sudden onset of coughing, hemoptysis, tachycardia, tachypnea, and hypoxia, and is dramatically improved with supportive care, which prevents severe sequelae. To our knowledge, there is no report of a patient developing NPPE after percutaneous endoscopic interlaminar lumbar discectomy. CASE PRESENTATION: Herein, we report the case of a 22-year-old amateur basketball player with L5/S1 disc herniation who developed NPPE during extubation after general anesthesia for a minimally invasive spinal surgery (percutaneous endoscopic interlaminar lumbar discectomy). The NPPE was treated by maintaining the airway patency, applying positive-pressure ventilation, administering dexamethasone and antibiotics, and limiting the volume of fluid infused. The patient had an uneventful postoperative course, and was discharged to his home on postoperative day 3. CONCLUSIONS: Although NPPE is an infrequent complication, especially in patients undergoing percutaneous endoscopic interlaminar lumbar discectomy, this case report highlights the importance of early diagnosis and prompt treatment of NPPE to prevent the development of potentially fatal complications.