Atsuhiko Hirasawa

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

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, &khgr;2 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 cages pathway. CONCLUSION: In posterior lumbar interbody fusion surgeries, bone fusion was achieved more quickly with the CBG technique than with the conventional technique. ABBREVIATIONS: CBG, compaction bone grafting IBG, impaction bone grafting LBG, loose bone grafting PLIF, posterior lumbar interbody fusion

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.

Two cases of pelvic sarcoma in the acetabulum with >10-year follow-ups after carbon ion radiotherapy

There are many cases of bone and soft-tissue sarcoma in which resection is difficult. This difficulty is typically related to the lesions original location or the possibility that resection could lead to a marked decline in the patients quality of life, based on postoperative motor dysfunction or neurological damage [1]. Moreover, even in cases where resection is possible, postoperative irradiation is recommended for patients who experience incomplete resection or exhibit positive surgical margins. However, many kinds of bone and soft-tissue sarcomas are radio-resistant tumours, and it is can be difficult to control them using X-ray radiation therapy. In the field of radiation oncology, heavy-ion beams are defined as radiation that is obtained by accelerating charged nuclei that are heavier than protons. Carbon ion radiotherapy is one type of heavyion radiotherapy having potential advantages over conventional radiotherapy [2]. For example, carbon ions provide better physical dose distribution, compared to conventional radiotherapy, because of the special characteristic of charged particle beams (the Bragg