Clinical Comparison of Unilateral Biportal Endoscopic Laminectomy versus Microendoscopic Laminectomy for Single-Level Laminectomy: A Single-Center, Retrospective Analysis.

BACKGROUND: The purpose of this study was to compare clinical results of microendoscopic laminectomy (MEL) with those of unilateral biportal endoscopic laminectomy (UBEL) in patients with single-level lumbar spinal canal stenosis. METHODS: The subjects consisted of 181 patients who underwent MEL (139 cases) and UBEL (42 cases) who were followed up for at least 6 months. All patients had lumber canal stenosis for 1 level. Outcomes of the patients were assessed with the duration of surgery, the bone resection area in 3-dimensional computed tomography, the facet preservation rates in computed tomography axial imagery, Visual Analog Scale (VAS) for low back pain, the Oswestry Disability Index, and the EuroQol 5-Dimensions questionnaire. RESULTS: The bone resection area in 3-dimensional computed tomography was 1.5 for MEL versus 1.0 cm2 for UBEL (P < 0.05). The facet preservation rates on the advancing side and the opposite side were 78% versus 86% (advancing side: MEL vs. UBEL) and 85% versus 94% (opposite side) (P < 0.05). The VAS (low back pain) score, VAS (leg pain), Oswestry Disability Index, and EuroQol 5-Dimension questionnaire significantly dropped in both groups at the final period (P < 0.05), however, exhibiting no difference between the 2 groups at each period. MEL resulted in greater numbers of complications, including 5 cases of hematoma paralysis, 8 cases of dura injury, 2 cases of reoperation, as opposed to zero cases of hematoma paralysis and only 2 cases of dura injury resulting from UBEL. CONCLUSIONS: The UBEL method is a more useful technique than the MEL method as it requires a smaller bone resection area and produces fewer complications.

Step-by-Step Sublaminar Approach With a Newly-Designed Spinal Endoscope for Unilateral-Approach Bilateral Decompression in Spinal Stenosis.

OBJECTIVE: Spinal stenosis is increasingly common due to population aging. In elderly patients with lumbar central canal stenosis (LCCS), minimizing muscle damage and bone resection is particularly important. We performed a step-by-step operation with a newly designed spinal endoscope to obtain adequate decompression in patients with spinal stenosis. METHODS: From April 2015 to August 2016, 78 patients (48 males, 30 females) with LCCS (91 segments) underwent endoscopic decompression using a newly designed endoscope system. The inclusion criteria were: (1) neurogenic intermittent claudication with or without radiculopathy, (2) LCCS, and (3) having exhausted conservative treatment (>3 months). The exclusion criteria were: (1) >10° of instability, (2) spondylolisthesis grade II or greater according to the Meyerding criteria, (3) foraminal stenosis, (4) vascular intermittent claudication, (5) infection, and (6) stenosis combined with malignancy. We performed a step-by-step procedure using a newly designed endoscope system for unilateral-approach bilateral decompression. We used the same incision for 2-3 segments, only moving the skin. RESULTS: The mean follow-up was 2.3±1.3 years. Excellent or good results were found according to the MacNab criteria in 85.9% of cases (67 of 78). The visual analogue scale, Japanese Orthopedic Association score, and Oswestry Disability Index showed significant decreases at 1 month, persisting until the 2-year follow-up. Dural tear occurred in 4 cases (5.1%), and patch repair was performed under endoscopy. No patients experienced aggravated instability requiring surgery. CONCLUSION: We obtained good results with endoscopic decompression surgery using a newly designed instrument that minimized muscle and bone damage in elderly patients with spinal stenosis.

Reliability of an Intraoperative Radiographic Anteroposterior View of the Spinal Midline for Detection of Pedicle Screws Breaching the Medial Pedicle Wall in the Thoracic, Lumbar, and Sacral Spine.

OBJECTIVE: The purpose of this study was to determine the sensitivity and specificity of using the spinal midline (M line) on a radiographic anteroposterior (AP) view for detecting pedicle screws (PSs) breaching the medial pedicle wall. METHODS: We retrospectively reviewed 145 patients who underwent fusion surgery using PSs between January 2006 and May 2017. We defined the M line as a line that connected the upper and lower spinous processes through the fixed vertebrae. The M line was positive if the tip of the PS crossed the M line. The reference standard was a computed tomography scan. The reliability of the M line was examined. RESULTS: The subjects included 145 patients (70 men and 75 women; mean age, 63.4 years). A total of 599 PSs were examined. Most cases were because of spondylolisthesis (66.9%). Most screws were inserted at a lower lumber level (77.6%). Analysis of the diagnostic accuracy of the M line yielded a sensitivity of 74.1% and a specificity of 95.3%. In addition, the positive predictive value of the M line was 42.6%, and the negative predictive value of the M line was 98.7%. CONCLUSIONS: Assessment of the M line via an intraoperative radiographic AP view is a simple, readily available, complementary method for detecting PSs that have breached the medial pedicle wall in the thoracic, lumbar, and sacral spine. In particular, the M line has a strong negative predictive value, which is much more meaningful.

Expression of Autophagy Signaling Molecules in the Outer Membranes of Chronic Subdural Hematomas.

Chronic subdural hematoma (CSDH) is fundamentally treatable, although it sometimes recurs. We observed, however, several cases of spontaneous resolution of CSDH outer membranes, even in a trabecular type of CSDH, after a trepanation surgical procedure. In this study, we examined the expression of molecules of the autophagy signaling pathway in CSDH outer membranes. Eight patients whose outer membranes were obtained successfully during trepanation were included in this study. By Western blot analysis, we examined the expression of mammalian target of rapamycin (mTOR); GßL; UNC-51-like kinase-1 (ULK1); Beclin-1; autophagy-related genes (Atg) 3, 5, 7, 12, 13, and 16L1ß,α; the autophagy marker Light Chain3A/B (LC3A/B); and ß-actin, which constitute the autophagy signaling pathway. The expression levels of Beclin-1, Atg12, and LC3A/B were also examined by immunohistochemistry. Almost all of these molecules could be detected in all samples. Beclin-1, Atg12, and LC3A/B were found to be localized in the endothelial cells of vessels and fibroblasts in CSDH. We detected molecules of the autophagy signaling pathway in CSDH outer membranes. Autophagy contributes to the tissue homeostatic process, maintaining cellular integrity by clearing debris. Our data suggest that autophagy might play an important role in the spontaneous resolution of CSDH. Therefore, these molecules may be novel therapeutic targets for the treatment of those with CSDH.

A double-blind randomized controlled trial of the local application of vancomycin versus ampicillin powder into the operative field for thoracic and/or lumbar fusions.

OBJECTIVERetrospective studies have reported that the local application of vancomycin (VCM) powder into the operative field decreases the incidence of surgical site infection (SSI) in thoracic and/or lumbar fusion. Authors of the present study prospectively evaluated the effects of VCM in patients undergoing thoracic and/or lumbar fusion.METHODSIn this randomized double-blind trial, 230 patients undergoing thoracic and/or lumbar fusion were randomly assigned to the local administration of VCM (interventional group, 1 g) or ampicillin (AMP; control group, 1 g) into the surgical field. The primary outcome was SSI results within 1 year of surgery.RESULTSThe trial was prematurely stopped according to predetermined rules. The results showed one superficial infection (0.9%, Staphylococcus aureus) and one deep infection (0.9%, S. aureus) in the VCM group and two superficial infections (1.8%, Staphylococcus epidermidis and culture negative) and one deep infection (0.9%, methicillin-resistant S. aureus) in the AMP group. No significant differences in infection rates were observed between the groups (p = 0.8).CONCLUSIONSThis double-blind randomized controlled trial demonstrated that the local application of VCM or AMP powder into the operative field in short thoracic and/or lumbar fusion procedures resulted in a similar incidence of SSI.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: randomized controlled trial; evidence: class III.Clinical trial registration no.: UMIN000009377 (umin.ac.jp/ctr).

Simple presurgical method of predicting C5 palsy after cervical laminoplasty using C5 nerve root ultrasonography.

OBJECTIVE: The incidence of C5 palsy after cervical laminoplasty is approximately 5%. Because C5 palsy is related to cervical foraminal stenosis at the C4-5 level, the authors hypothesized that cervical foraminal stenosis can be diagnosed by examining the C5 nerve root (NR) using ultrasonography. The purpose of this study was to investigate whether postoperative C5 palsy could be predicted using ultrasonography. METHODS: This study used a prospective diagnosis design. In total, 140 patients undergoing cervical laminoplasty were examined with ultrasound. The cross-sectional area (CSA) of the C5 NR was measured on both sides before surgery, and the incidence of postoperative C5 palsy was examined. The difference between the CSA of the patients with and without C5 palsy and the lateral differences in the C5 palsy group were determined. RESULTS: The incidence of C5 palsy was 5% (7 cases). Symptoms manifested at a median of 5 days after surgery (range 1-29 days). The CSA of the C5 NR on the affected side was significantly enlarged in the C5 palsy group compared with that in the no-C5 palsy group (p = 0.001). In addition, in the patients who had C5 palsy, the CSA of the C5 NR was significantly enlarged on the affected side compared with that on the unaffected side (p = 0.02). Receiver operating characteristic analysis indicated that the best threshold value for the CSA of the C5 NR was 10.4 mm2, which provided 91% sensitivity and 71% specificity. CONCLUSIONS: C5 palsy may be predicted preoperatively using ultrasound. The authors recommend the ultrasonographic measurement of the CSA of the C5 NR prior to cervical laminoplasty.

Effect of an intensive conservative therapy with daily teriparatide administration and rehabilitation for osteoporotic delayed vertebral collapse and paralysis.

Although patients with osteoporotic delayed vertebral collapse (ODVC) have frequently been treated surgically, the efficacy and limitation of conservative treatment for it have not yet been reported. The purpose of this study was to investigate the effectiveness and limitation of further intensive conservative treatment for patients with ODVC.Patients treated for ODVC from 2011 to 2014 with a follow-up period of more than 1 year were eligible. The fundamental treatment strategy consisted of surgical treatment following intensive conservative treatment with daily teriparatide and rehabilitation for 3 months. We conducted a surgical treatment for patients who could not keep standing position by themselves because of prolonged leg paralysis or intolerable back pain. We performed a logistic regression model in which surgical treatment was set as an objective variable, and other related factors including sex, age, the level of affected vertebrae, the quality of paralysis, changing rate (δ) of spinal canal encroachment, local kyphotic angle, mobility of collapsed vertebrae, EuroQol questionnaires (EQ5D), numerical rating scale (NRS), and Frankel grade as explanatory variables. We also plotted receiver operating curves (ROCs) to investigate the cutoff values of parameters at the baseline.Thirty patients (6 males and 24 females, mean age 76.7 years) were enrolled. Eventually 12 out of 30 patients avoided surgical treatment because their symptoms were improved. Logistic regression showed that δ of local kyphotic angle (odds ratio: 1.072), P = .01), mobility of collapsed vertebrae (1.063, 0.01), EQ5D (0.98, 0.04), and NRS (1.113, 0.01) were significantly correlated with the need for surgical treatments. Among the factors at baseline, only the mobility of collapsed vertebrae showed a significant value of area under a curve (AUC = 0.727, P = .008).The results that 40% of patients with ODVC did not need further surgical treatment after the intensive conservative treatment was of great significance. Patients with greater mobility of collapsed vertebrae might be treated surgically as quickly as possible.

Expression of Caspase Signaling Components in the Outer Membranes of Chronic Subdural Hematomas.

Chronic subdural hematoma (CSDH) is fundamentally treatable through surgery, although CSDH recurs in some cases. We have observed several cases of spontaneous resolution of CSDH outer membranes, including in trabecular CSDH, after trepanation surgery. In this study, we examined the expression of molecules involved in caspase signaling in CSDH outer membranes. Eight patients whose outer membranes were obtained successfully during trepanation surgery were included in this study. The expression of Fas; Fas-associated death domain (FADD); tumor necrosis factor receptor type 1-associated death domain (TRADD); receptor-interacting protein (RIP); caspases 3, 7, 8, and 9; poly-(ADP-ribose) polymerase (PARP); DNA fragmentation factor 45 (DFF45) and ß-actin was examined by Western blot analysis. The expression levels of PARP, caspase-3, and cleaved caspase-3 were also examined by immunohistochemistry. Fas; FADD; TRADD; RIP; caspases 3, 7, 8, and 9; PARP, and DFF45 were detected in nearly all samples. Caspase-3 and PARP were localized in the endothelial cells of vessels and in fibroblasts in CSDH outer membranes. In addition, cleaved caspase-3 was detected in fibroblasts. We detected molecules of the caspase signaling pathway in CSDH outer membranes. In particular, cleaved caspase-3 was detected, which suggests that apoptosis may occur within these membranes. Thus, during the growth of CSDH outer membranes, the caspase signaling pathway may be restrained. Once the pathway is activated, gradual resolution of CSDH outer membranes may occur. Therefore, these molecules may be novel therapeutic targets for intractable CSDH.

Contusional Cerebellar Hemorrhage Related to Placement in the Protrusion Position After Atlantoaxial Fusion.

BACKGROUND: Various complications after C1 lateral mass and C2 pedicle screw fusion surgery (C1LM-C2PSFS) have been reported. However, to our knowledge, this is the first report of contusional cerebellar hemorrhage caused by placement in the protrusion (chin-out) position after C1LM-2PSFS. CASE DESCRIPTION: An 81-year-old woman complaining of gait disturbance and clumsiness of both hands was diagnosed with cervical myelopathy with atlantoaxial subluxation. After we performed C1LM-C2PSFS, her neurologic deficits gradually improved, and there was no radiologic evidence of construct failure. One month after surgery, she had severe headache and vomiting immediately after taking some medications while in the protrusion position. Head computerized tomography scan showed left cerebellar hemorrhage, and titanium rods penetrated the occipital bone on both sides. Flexion/extension radiography showed no loosening of any screws or rods. However, protrusion radiography showed that the tip of the left titanium rod intruded into the intracranial region. We considered that the penetration of the occipital bone by the left titanium rod caused the contusional left cerebellar hemorrhage. We immediately performed revision surgery to replace the titanium rods on each side with shorter rods, and no cerebrospinal fluid leakage was observed. The headache disappeared after the revision surgery. CONCLUSIONS: We report a case of contusional cerebellar hemorrhage caused by the intrusion of a rod into the occipital bone when the patient was placed in the protrusion position. The rod length on the cranial side must be as short as possible, with careful consideration of placing the head in the protrusion position after C1LM-2PSFS surgery.

Activation of Nuclear Factor-kappa B in Endothelial Cells of Chronic Subdural Hematoma Outer Membranes.

BACKGROUND: Chronic subdural hematoma (CSDH) is considered an angiogenic and inflammatory disease. Nuclear factor-kappa B (NF-κB) induces the production of inflammatory cytokines and adhesion molecules, which play an essential role in angiogenesis and inflammation. Recently, the double-stranded RNA-activated protein kinase (PKR) was shown to directly interact with NF-κB subunits to influence its transcriptional activity. OBJECTIVE: To examine the expression of NF-κB signaling pathway components and PKR in CSDH outer membranes. METHODS: Eight patients whose outer membranes were successfully obtained during trepanation surgery were included in this study. The IκBα, IKKß, IKKγ, NF-κB, phosphorylated ( p )-NF-κB, and PKR expression levels were examined using western blotting analysis. NF-κB expression was also examined using immunohistochemistry. We investigated whether CSDH fluid could activate NF-κB in cultured endothelial cells in Vitro. RESULTS: The IκBα, IKKß, IKKγ, and NF-κB levels were approximately the same. Additionally, p -NF-κB and PKR were detected at similar levels. Immunostaining showed that NF-κB was expressed in the vascular endothelium. p -NF-κB expression in endothelial cells was significantly induced immediately after treatment with CSDH fluid. Furthermore, NF-κB activation was significantly inhibited by treatment with antibodies directed against vascular endothelial growth factor. CONCLUSION: PKR might activate NF-κB through vascular endothelial growth factor in endothelial cells, which might be associated with endothelial cell proliferation in the CSDH outer membrane. Thus, the NF-κB signaling pathway could play a critical role in CSDH growth.

Ultrasonography has a diagnostic value in the assessment of cervical radiculopathy: A prospective pilot study.

OBJECTIVE: This study investigated the diagnostic accuracy of the difference in the cross-sectional areas (CSAs) of affected cervical nerve roots (NRs) for diagnosing cervical radiculopathy (CR). METHODS: In total, 102 CR patients and 219 healthy volunteers were examined with ultrasound. The CSA of the cervical NR at each level was measured on the affected side and the contralateral side in CR patients by blinded ultrasonographic technicians. The difference between the CSAs of CR patients and normal volunteers and the difference in the laterality of CSA at the same affected level (ΔCSA) were calculated for each cervical level. RESULTS: The CSAs of the affected NRs in CR patients were significantly larger than those of the unaffected NRs in CR patients and those of the control group at the C5, C6 and C7 levels (P<0.005). ΔCSA was also significantly larger in the CR group at all levels (P<0.001). A receiver operating characteristic analysis demonstrated that the threshold values were 9.6 mm2 (CSA) for C5NR and 15 mm2 for both C6NR and C7NR. CONCLUSIONS: This study revealed that the CSAs of affected NRs were enlarged and that the laterality of the CSA (ΔCSA) was greater in CR patients than in control patients. KEY POINTS: • Cervical radiculopathy is diagnosed through ultrasonographic measurement of the CSAs. • The CSAs of affected nerve roots were significantly enlarged. • The ΔCSA in the CR group was significantly higher than in the control group. • Diagnostic CSA and ΔCSA thresholds were identified.

Inhibitory Mechanism of the Outer Membrane Growth of Chronic Subdural Hematomas.

We previously demonstrated that the inflammatory cytokine interleukin-6 (IL-6) activates the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway in fibroblasts within the outer membranes of chronic subdural hematomas (CSDHs), and the activation of this pathway may induce CSDH outer membrane growth. The inhibitory system for this signal transduction pathway is unknown. CSDH fluids were obtained from 10 patients during trepanation surgery as the case group, and cerebrospinal fluid (CSF) samples were obtained from seven patients suffering from subarachnoid hemorrhage (SAH) on Day 1 as the control group. The concentrations of IL-6, soluble IL-6 receptor (sIL-6R), and soluble gp130 (sgp130) in CSDH fluid and CSF were measured using enzyme immunoassay kits. The co-localization of IL-6 and sgp130 in CSDH fluid was examined by immunoprecipitation. The expression levels of STAT3, JAK2, suppressor of cytokine signaling 3 (SOCS3), and protein inhibitor of activated Stat3 (PIAS3) in the outer membranes of CSDHs were examined by immunostaining. Soluble IL-6R and sgp130 concentrations in CSDH fluid were significantly higher than those in CSF after SAH. Sgp130 and IL-6 were co-immunoprecipitated from CSDH fluid. Immunostaining revealed STAT3, JAK2, SOCS3, and PIAS3 expression in fibroblasts located in the outer membranes of CSDHs. Soluble gp130 binds to IL-6/sIL-6R and acts as an antagonist of the JAK/STAT signaling pathway. SOCS3 also binds to JAK and inhibits its signaling pathway. In addition, PIAS3 regulates STAT3 activation. These factors might down-regulate the IL-6/JAK/STAT signaling pathway in fibroblasts within CSDH outer membranes. Therefore, these molecules may be novel therapeutic targets for the inhibition of CSDH growth.

Surgical Intervention for Instability of the Craniovertebral Junction.

Surgical approaches for stabilizing the craniovertebral junction (CVJ) are classified as either anterior or posterior approaches. Among the anterior approaches, the established method is anterior odontoid screw fixation. Posterior approaches are classified as either atlanto-axial fixation or occipito-cervical (O-C) fixation. Spinal instrumentation using anchor screws and rods has become a popular method for posterior cervical fixation. Because this method achieves greater stability and higher success rates for fusion without the risk of sublaminar wiring, it has become a substitute for previous methods that used bone grafting and wiring. Several types of anchor screws are available, including C1/2 transarticular, C1 lateral mass, C2 pedicle, and translaminar screws. Appropriate anchor screws should be selected according to characteristics such as technical feasibility, safety, and strength. With these stronger anchor screws, shorter fixation has become possible. The present review discusses the current status of surgical interventions for stabilizing the CVJ.

Effect of Denosumab Administration on Lumbar Vertebral Strength of Patients with Vertebral Bony Metastases: Preliminary Study.

The purpose of this study was to examine the usefulness of administration of denosumab (antibody against tumor necrosis factor superfamily member 11) as a preventative therapy for skeletal-related events (SREs), such as fracture or paralysis, by computed-tomography (CT)-based on the finite element method (FEM). Patients who had undergone treatment for vertebral metastases with denosumab administration from December 2013 to August 2015 at our Institution were reviewed. We investigated patient data at the time before denosumab administration and at 1, 3 and 6 months using CT. A total of six patients were eligible; four males and two females, with ages ranging from 35 to 73 years, with a mean age of 56 years. Repeated measures analysis of variance showed a significant increase (p=0.0055, F=10.67). To our knowledge, this is the first article to substantiate the effects of the SRE-preventative drug denosumab.

The prevalence of diffuse idiopathic skeletal hyperostosis in Japan - the first report of measurement by CT and review of the literature.

BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) is prone to be accompanied by a spinal column fracture which is resistant to conservative therapy. This major characteristic of DISH is not recognized adequately by physicians, because the disease's detailed pathological condition has not yet been investigated. Therefore, the purposes of this study were to investigate the prevalence of DISH using computed tomography (CT), and to validate the reliability of CT interpretation. METHODS: Subjects were 558 patients (300 male and 258 female) who underwent both CT of chest to pelvis and x-ray of chest and abdomen from August 2011 to July 2012 at any department other than orthopedic surgery in our institution. The definition of DISH based on x-ray as well as CT was the presence of consecutive fused vertebral bodies according to Resnick's criteria. The prevalence of DISH based on both modalities was calculated in all subjects. For 107 subjects extracted at random, intra- (Cohen kappa) and inter-observer error (Fleiss kappa) were calculated and the levels of fused segments were investigated. RESULTS: Ninety-eight of 558 subjects (17.6%) were diagnosed as DISH by x-ray, and 152 (27.2%) by CT. Among males, 70 of 300 subjects (23.3%) were diagnosed by x-ray, and 116 (38.7%) by CT. Among females, 28 of 258 subjects (10.9%) were diagnosed by x-ray and 36 (14.0%) by CT. The levels of fused segments were presented from thoracic spine to lumbar spine, especially the middle and lower thoracic spine. Cohen kappa of x-ray was 0.587, and that of CT was 0.825. Fleiss kappa of x-ray was 0.552, and that of CT was 0.643. CONCLUSIONS: The prevalence of DISH based on CT was 27.1%, which was higher than that of x-ray. In addition, intra- and inter-observer error by review of CT was less than that of x-ray. CT evaluation would be a better method for precise understanding of the state of DISH.

Prevalence of C7 level anomalies at the C7 level: an important landmark for cervical nerve ultrasonography.

BACKGROUND: Recently, various examination and intervention techniques using cervical nerve ultrasonography have been developed. The specific shapes of the C7 transverse process and vertebral artery in front of the C7 transverse process have become landmarks. PURPOSE: To determine the prevalence of anomalies and anomalous vertebral artery entrances at the C7 transverse process. MATERIAL AND METHODS: The records of patients who underwent plain or contrast-enhanced neck or cervical spine computed tomography (CT) were reviewed. The examinations were scored for the anomalous presence of anterior tubercles or cervical ribs as well as vertebral artery entrances in the C7 transverse process. The prevalence of anomalies was compared based on patient sex and age. RESULTS: Evaluating the examinations from 2067 patients (1046 men; 1021 women), 1% of patients exhibited an anomalous presence of anterior tubercles, and 0.3% of patients displayed cervical ribs at the C7 transverse process. The prevalence of anomalies process was significantly higher in men aged less than 40 years than in older men (P < 0.001), whereas the prevalence was not higher in women aged less than 40 years than in older women. The prevalence of vertebral artery entry into the C7 transverse foramen was 0.6%. CONCLUSION: Although an anomalous vertebral artery entry into the C7 transverse foramen was rare, the prevalence of an anomaly at the C7 transverse process was higher in men aged less than 40 years. Therefore, we recommend performing CT in younger men before cervical nerve ultrasonographic intervention to avoid misinterpretations at the cervical level.

Risks for Vascular Injury During Anterior Cervical Spine Surgery: Prevalence of a Medial Loop of Vertebral Artery and Internal Carotid Artery.

STUDY DESIGN: Observational study using a retrospective single-institute database. OBJECTIVE: To investigate the prevalence of a medial loop (ML) of the vertebral artery (VA) and internal carotid artery (ICA), which might be an anatomical risk factor for arterial injury in anterior cervical surgeries. SUMMARY OF BACKGROUND DATA: Anterior cervical spine surgeries are generally considered to be safe and effective. VA injury is one of the most serious complications during anterior procedures. Several articles have reported this complication, which might be because of the anomalous course of VA at V2 segment. The prevalence and anatomical features of those high-risk cases were, however, not investigated. METHODS: Consecutive Japanese subjects, who underwent contrast-enhanced computed tomography (CT) or computed tomographic angiography (CTA) for reasons other than evaluation of cervical artery disease from November 2011 to October 2012 in our institution, were reviewed. Exclusion criteria included poor images, past surgery, and endovascular intervention of cervical spine and its vessels. The definition of ML was set as the course of VA and ICA extended medially inside the uncovertebral joint. We also investigated whether those anomalous courses were detectable by plain CT. RESULTS: A total of 1251 subjects with age ranging from 14 to 93 years with a mean of 56.1 years were surveyed. Among them, 1054 subjects were eligible and the others were excluded. A total of 421 subjects were male, and 633 were female. There were 10 cases (1%) with an ML of the VA, and 2 (0.2%) cases with a medial loop of internal carotid artery. Five of the 10 cases with a medial loop of vertebral artery were aberrant into the vertebral body, which were detectable by plain CT. Importantly, the other five cases could not be seen on the CT. CONCLUSION: One percent of all subjects showed higher anatomical risk for VA and ICA injury during anterior surgery, half of which were undetectable by plain CT. Preoperative evaluation for vascular anatomy may be necessary for safer surgical treatment. LEVEL OF EVIDENCE: 4.

A Compaction Bone Grafting Technique Leads to Early Bone Fusion in Cases of Posterior Lumbar Interbody Fusion.

BACKGROUND: The impaction bone grafting technique is a popular approach for achieving complete bone fusion during hip surgery or total knee arthroplasty. We hypothesized that compaction bone grafting (CBG), a modified version of impaction bone grafting, could be applied to lumbar fusion surgery. OBJECTIVE: To compare the bone fusion rates and durations achieved using the CBG technique and a conventional loose bone grafting technique. METHODS: We retrospectively reviewed 89 patients who underwent single-level posterior lumbar interbody fusion at the university hospital; 35 other posterior lumbar interbody fusion recipients were excluded due to undergoing multilevel fusion, prior lumbar surgery, trauma, infection, or inadequate computed tomographic data. Computed tomographic-based bone fusion assessments were obtained using the Brantigan, Steffee, and Fraser criteria at 1 and 2 years after surgery. RESULTS: The baseline characteristics of the CBG (n = 42) and loose bone grafting (n = 47) groups did not significantly differ. Fusion assessments indicated that significantly superior bone fusion rates were achieved at 1 year after surgery in the CBG group than in the loose bone grafting group (P = .04, χ2 test). However, the bone fusion rates of the 2 groups at 2 years after surgery did not significantly differ (P = .3). A nonsymptomatic surgical complication occurred in the CBG group when a spacer was inserted into the intervertebral space; specifically, the spacer slipped out of the right psoas muscle because a large quantity of compaction bone grafts disrupted the cage's pathway. CONCLUSION: In posterior lumbar interbody fusion surgeries, bone fusion was achieved more quickly with the CBG technique than with the conventional technique.

Pitfalls in the Management of Atlanto-Occipital Dislocation.

Atlanto-occipital dislocation (AOD) is rarely seen in clinic because it is characteristically immediately fatal. With recent progress in the pre-hospital care, an increasing number of AOD survivors have been reported. However, because the pathophysiology of AOD is not clearly understood yet, the appropriate strategy for the initial management remains still unclear. We report a case of successful AOD treatment and describe important points in the management of this condition. It is important to note that abducens nerve palsy is a warning sign of AOD and that AOD can result in a life-threatening distortion of the arteries and the brain stem. We recommend the application of a halo vest to protect the patient's neural and vascular competence as the immediate initial step in the treatment of AOD. Horn's grading system is useful in assessing indications for surgery. Finally, when performing posterior fixation, C2 should be included because of the anatomy of the ligamentous architecture.