Norimitsu Wakao

Vertebral artery variations and osseous anomaly at the C1-2 level diagnosed by 3D CT angiography in normal subjects.

IntroductionThe craniovertebral junction is anatomically complicated. Representative vertebral artery (VA) variations include the persistent first intersegmental artery (FIA), fenestration of the VA above and below C1 (FEN), posterior inferior cerebellar artery (PICA) from C1/2, and high-riding VA (HRVA). The ponticulus posticus (PP) is a well-known osseous anomaly at C1. Although those anomalies are frequent in patients with cervical deformity, the prevalence of these in subjects with normal cervical spines is still unknown. The aim of this study is to investigate the variations and prevalence of vascular and osseous anomalies based on three-dimensional computed tomographic (3D CT) angiography in patients without any cervical diseases, such as rheumatoid arthritis, Klippel-Feil syndrome, or Down syndrome.MethodsEligible subjects were patients who underwent 3D CT angiography by the Department of Otorhinolaryngology and Internal Medicine from January 2009 to October 2013 in our institution. The authors defined a HRVA as a C2 pedicle with a maximum diameter of 4xa0mm or less.ResultsAmong 480 subjects with a mean age of 63.1xa0years, 387 patients were eligible. One hundred and eighteen subjects were female, and 269 were male. HRVA was observed in 10.1xa0% of patients (39 out of 387 cases), FIA in 1.8xa0% (7 cases), FEN in 1.3xa0% (5 cases), and PICA in 1.3xa0% (5 cases). PP was observed in 6.2xa0% of patients (24 cases).ConclusionAccording to past reports, many VA anomalies could be attributed to congenital or acquired conditions (e.g., rheumatoid arthritis). However, VA anomalies appear to exist even in patients without any such cervical diseases.

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

BACKGROUNDnDiffuse 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 diseases 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.nnnMETHODSnSubjects 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 2012xa0at 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 Resnicks 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.nnnRESULTSnNinety-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.nnnCONCLUSIONSnThe 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.

Impact of spinal alignment and back muscle strength on shoulder range of motion in middle-aged and elderly people in a prospective cohort study.

PurposeThe relationship between spine and shoulder motion has not been well evaluated. The purpose of this study was to clarify the relationships among thoracic kyphosis and lumbar lordosis, spinal range of motion (ROM), spinal alignment and shoulder ROM.MethodsEvaluation of spinal alignment was prospectively conducted in 317 subjects (114 males and 203 females, the average age: 67xa0years) who attended a public health checkup. Shoulder ROM with an angle meter and shoulder pain were evaluated. Thoracic kyphosis angle, lumbar lordosis angle, thoracic ROM, lumbar ROM and spinal inclination angle were measured using SpinalMouse®. The relationships of these factors with grip strength, back muscle strength, physical ability, osteoporosis and body mass index were examined and multivariate logistic regression analysis was performed to identify the risk factors for limited shoulder ROM.ResultsLimited shoulder flexion was found in 35 patients (11xa0%) and limited abduction in 50 patients (16xa0%). In multivariate logistic regression analyses adjusted for age, shoulder pain and other parameters, increased thoracic kyphosis angle and increased spinal inclination angle were risk factors for limited shoulder flexion (pxa0<xa00.05). Increased thoracic kyphosis angle and weak back muscle strength were also determined as risk factors for limited shoulder abduction (pxa0<xa00.05).ConclusionsThis study provides the first evidence that increased thoracic kyphosis, increased spinal inclination and weak back muscle strength are the risk factors for limited shoulder ROM. These results suggest that maintenance of spinal alignment and back muscle strength may be important for better shoulder ROM.

Variance of cervical vertebral artery measured by CT angiography and its influence on C7 pedicle anatomy.

Study Design. Observational study using a retrospective single-institute database. Objective. To investigate the variance of the vertebral artery (VA) V2 segment and the anatomical features of the C7 pedicle with or without VA entry based on computed tomographic (CT) angiography in 919 consecutive Japanese subjects. Summary of Background Data. Generally, the level of the VA entrance into the transverse foramen is assumed to be C6. Therefore, surgeons tend to pay less attention to VA injury when inserting a C7 pedicle screw. However, anomalies at C7 surely exist and are considered to be 1 of the major risk factors for VA injury during posterior instrumentation. Methods. Subjects who underwent contrast-enhanced CT or CT angiography from November 2011 to October 2012 were eligible. The entrance into the transverse foramen was reviewed. In addition, anatomical features of C7 with or without VA entrance were measured. Results. A total of 919 subjects with a mean age of 56.1 years were surveyed. From among 1838 VA courses, VA entered the C6 transverse foramen in 95.6% of specimens (1757 of 1838 VA courses). Sixty-seven of 919 subjects (7.3%) had a unilateral anomaly and 7 (0.8%) had a bilateral anomaly. An abnormal level of entrance was observed in 8.1% of subjects (74 of 919 patients), and 4.4% of specimens (81 of 1838 VA courses), with a level of entrance into the C4, C5, or C7 transverse foramen in 0.5% (n = 10), 3.1% (n = 57), and 0.8% (n = 14) of all specimens, respectively. C7 transverse foramen with a VA entrance was wider in those without a VA entrance, and abnormal cases frequently showed an uneven transverse foramen. Therefore, the C7 pedicle diameter with abnormal VA entrance was significantly narrower in those without VA entrance (P < 0.01; t test). Conclusion. CT angiography is recommended in cases with an uneven transverse foramen for confirming vascular anomaly. Level of Evidence: 2

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

Resection of Beak-Type Thoracic Ossification of the Posterior Longitudinal Ligament from a Posterior Approach under Intraoperative Neurophysiological Monitoring for Paralysis after Posterior Decompression and Fusion Surgery

Study Design Prospective clinical study. Objective Posterior decompression and fusion surgery for beak-type thoracic ossification of the posterior longitudinal ligament (T-OPLL) generally has a favorable outcome. However, some patients require additional surgery for postoperative severe paralysis, a condition that is inadequately discussed in the literature. The objective of this study was to describe the efficacy of a procedure we refer to as “resection at an anterior site of the spinal cord from a posterior approach” (RASPA) for severely paralyzed patients after posterior decompression and fusion surgery for beak-type T-OPLL. Methods Among 58 consecutive patients who underwent posterior decompression and fusion surgery for beak-type T-OPLL since 1999, 3 with postoperative paralysis (5%) underwent RASPA in our institute. Clinical records, the Japanese Orthopaedic Association score, gait status, intraoperative neurophysiological monitoring (IONM) findings, and complications were evaluated in these cases. Results All three patients experienced a postoperative decline in Manual Muscle Test (MMT) scores of 0 to 2 after the first surgery. RASPA was performed 3 weeks after the first surgery. All patients showed gradual improvements in MMT scores for the lower extremity and in ambulatory status; all could walk with a cane at an average of 4 months following RASPA surgery. There were no postoperative complications. Conclusions RASPA surgery for beak-type T-OPLL after posterior decompression and fusion surgery resulted in good functional outcomes as a salvage surgery for patients with severe paralysis. Advantages of RASPA include a wide working space, no spinal cord retraction, and additional decompression at levels without T-OPLL resection and spinal cord shortening after additional dekyphosis and compression maneuvers. When used with IONM, this procedure may help avoid permanent postoperative paralysis.

A Simple, 10-minute Procedure for Transforaminal Injection under Ultrasonic Guidance to Effect Cervical Selective Nerve Root Block

The aim is to provide a detailed procedure of a simple and 10-minute cervical nerve root block (CNRB) under ultrasonic guidance, and to report the clinical outcomes, disorders, and complications. Records of patients who had undergone CNRB, were reviewed under ultrasonic guidance at the hospital from 2010 through 2012. The procedure is described in detail. Arm and shoulder pain was evaluated by use of the visual analogue scale (VAS). Forty-three patients agreed to undergo CNRB under ultrasonic guidance. Nerve roots from C5 to C8 were affected in 41, and these nerve roots were readily distinguished. Two of the 43 participants did not receive injections because impediments in visualizing the affected nerve root. Of the 41 who received injections, radicular pain immediately disappeared in 39, who continued to feel pain relief 1 month later. However, pain recurred in 15 patients (38%), of whom 11 underwent cervical spine surgery. The rest of 24 patients felt sustained pain relief longer than 3 months after the injection, significantly. Although one patient had recurrent radicular pain 10 months later, the pain could be controlled by medication. At the final follow-up periods, 17.2 (10–24 months), the median VAS score of the patients, 23 (0 to 71 mm), was significantly improvement (P = 0.001) in comparison to before injection 88 (range; 56–100). No complications occurred. The cervical nerve root block under ultrasonic guidance simply, safely, and efficaciously decreased radicular pain for 17.2 months in 62% patients with intolerable radicular pain.

Rapid Worsening of Symptoms and High Cell Proliferative Activity in Intra- and Extramedullary Spinal Hemangioblastoma: A Need for Earlier Surgery

Study Design A retrospective analysis of a prospective database. Objective To compare preoperative symptoms, ambulatory ability, intraoperative spinal cord monitoring, and pathologic cell proliferation activity between intramedullary only and intramedullary plus extramedullary hemangioblastomas, with the goal of determining the optimal timing for surgery. Methods The subjects were 28 patients (intramedullary only in 23 cases [group I] and intramedullary plus extramedullary in 5 cases [group IE]) who underwent surgery for spinal hemangioblastoma. Preoperative symptoms, ambulatory ability on the McCormick scale, intraoperative spinal cord monitoring, and pathologic findings using Ki67 were compared between the groups. Results In group IE, preoperative motor paralysis was significantly higher (100 versus 26%, p < 0.005), the mean period from initial symptoms to motor paralysis was significantly shorter (3.5 versus 11.9 months, p < 0.05), and intraoperative spinal cord monitoring aggravation was higher (65 versus 6%, p < 0.05). All 5 patients without total resection in group I underwent reoperation. Ki67 activity was higher in group IE (15% versus 1%, p < 0.05). Preoperative ambulatory ability was significantly poorer in group IE (p < 0.05), but all cases in this group improved after surgery, and postoperative ambulatory ability did not differ significantly between the two groups. Conclusions Intramedullary plus extramedullary spinal hemangioblastoma is characterized by rapid preoperative progression of symptoms over a short period, severe spinal cord damage including preoperative motor paralysis, and poor gait ability compared with an intramedullary tumor only. Earlier surgery with intraoperative spinal cord monitoring is recommended for total resection and good surgical outcome especially for an IE tumor compared with an intramedullary tumor.

Lumbar extraforaminal entrapment: performance characteristics of detecting the foraminal spinal angle using oblique coronal MRI. A multicenter study

BACKGROUND CONTEXTnPrevious conventional magnetic resonance imaging reports on extraforaminal entrapment (e-FE) on L5-S1 have been problematic because of their complexity or lack of sensitivity and specificity. In this study, we propose a simple diagnostic method for e-FE.nnnPURPOSEnThe purpose of this study was to determine the sensitivity and specificity of using the difference in the foraminal spinal nerve (FSN) angle of the L5 nerve, as determined by oblique coronal T2-weighted imaging (OC-T2WI), for diagnosing L5-S1 unilateral e-FE.nnnSTUDY DESIGNnThe study design involves diagnostic accuracy with retrospective case-control study.nnnPATIENT SAMPLEnSeventy consecutive patients with unilateral L5 radiculopathy who underwent unilateral L5-S1 extraspinal canal decompression for e-FE or 4/5 intraspinal canal decompression for lumbar spinal canal stenosis between 2009 and 2013 were included.nnnOUTCOME MEASURESnThe Japanese Orthopedic Association score, Visual Analog Scale score for leg pain, and OC-T2WI for the FSN angle of the L5 nerve were examined.nnnMETHODSnThe 70 patients were divided into two groups: Group A (n=21) with unilateral L5-S1 e-FE and Group B (n=49) with intraspinal canal L4-L5. Group C (n=44) comprised the control group, which included only patients with back pain without leg radiculopathy. All patients underwent OC-T2WI, and the differences in the FSN angle of the fifth lumbar spinal nerve between the symptomatic and asymptomatic sides (ΔFSN angle) were examined and compared among the groups.nnnRESULTSnThere were no significant differences in the patient characteristics among the three groups. The ΔFSN angle was 17° in Group A, 4.8° in Group B, and 6.4° in Group C, and the laterality was significantly larger in Group A than in the other two groups. A receiver-operating characteristic curve showed areas under the curve between groups A and B and between groups A and C of 0.93 and 0.97, respectively. In addition, the cutoff value of the ΔFSN angle (10°) indicated diagnostic accuracies of 94% and 91% (sensitivity and specificity) and of 93% and 95%, respectively.nnnCONCLUSIONSnDetermining differences in the FSN angle between the symptomatic andxa0asymptomatic sides of greater than 10° via OC-T2WI represented a simple, readily available, and complementary diagnostic method for lumbar e-FE.

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

ObjectiveThis 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).MethodsIn 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.ResultsThe 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 9.6xa0mm2 (CSA) for C5NR and 15xa0mm2 for both C6NR and C7NR.ConclusionsThis 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.