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Masahiko Watanabe, Daisuke Sakai, Daisuke Matsuyama, Yukihiro Yamamoto, Masato Sato and Joji Mochida

Object

The purpose of this study was to identify risk factors for surgical site infection after spine surgery, noting the amount of saline used for intraoperative irrigation to minimize wound contamination.

Methods

The authors studied 223 consecutive spine operations from January 2006 through December 2006 at our institute. For a case to meet inclusion criteria as a site infection, it needed to require surgical incision and drainage and show positive intraoperative cultures. Preoperative and intraoperative data regarding each patient were collected. Patient characteristics recorded included age, sex, and body mass index (BMI). Preoperative risk factors included preoperative hospital stay, history of smoking, presence of diabetes, and an operation for a traumatized spine. Intraoperative factors that might have been risk factors for infection were collected and analyzed; these included type of procedure, estimated blood loss, duration of operation, and mean amount of saline used for irrigation per hour. Data were subjected to univariate and multivariate logistic regression analyses.

Results

The incidence of surgical site infection in this population was 6.3%. According to the univariate analysis, there was a significant difference in the mean duration of operation and intraoperative blood loss, but not in patient age, BMI, or preoperative hospital stay. The mean amount of saline used for irrigation in the infected group was less than in the noninfected group, but was not significantly different. In the multivariate analysis, sex, advanced age (> 60 years), smoking history, and obesity (BMI > 25 kg/m2) did not show significant differences. In the analysis of patient characteristics, only diabetes (patients receiving any medications or insulin therapy at the time of surgery) was independently associated with an increased risk of surgical site infection (OR 4.88). In the comparison of trauma and elective surgery, trauma showed a significant association with surgical site infection (OR 9.42). In the analysis of surgical factors, a sufficient amount of saline for irrigation (mean > 2000 ml/hour) showed a strong association with the prevention of surgical site infection (OR 0.08), but prolonged operation time (> 3 hours), high blood loss (> 300 g), and instrumentation were not associated with surgical site infection.

Conclusions

Diabetes, trauma, and insufficient intraoperative irrigation of the surgical wound were independent and direct risk factors for surgical site infection following spine surgery. To prevent surgical site infection in spine surgery, it is important to control the perioperative serum glucose levels in patients with diabetes, avoid any delay of surgery in patients with trauma, and decrease intraoperative contamination by irrigating > 2000 ml/hour of saline in all patients.

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Masahiko Watanabe, Daisuke Sakai, Yukihiro Yamamoto, Masato Sato and Joji Mochida

Object

Extension teardrop fracture of the axis is an extremely rare cervical spinal injury. The classic clinical features, which have mainly been described by radiologists rather than spine surgeons, include its occurrence in elderly patients with osteoporosis, an association with minimal or no prevertebral soft-tissue swelling, and an absence of associated neurological deficit. However, recent case studies indicate notable exceptions to these clinical features, although few studies have investigated osteoporosis in these patients. The purpose of the present study was to clarify the clinical features of extension teardrop fracture of the axis.

Methods

The authors retrospectively reviewed data obtained in 13 patients with regard to their injury etiology, neurological deficit, treatment and outcome (residual neck pain), and imaging findings (size and displacement of the fragment, C2–3 subluxation, disc injury, and osteoporosis of the axis).

Results

Extension teardrop fracture of the axis constituted 11.6% of upper cervical spinal injuries at the authors' institute. The mean age of the patients was 49.5 years and distinct osteoporosis was identified in only 1 patient. A C2–3 subluxation was observed in 2 patients, in whom the displacement of the fragment was significant, although its size did not appear to have an effect. Magnetic resonance imaging, undertaken in 7 patients within 48 hours of injury, showed no disc injuries. Instability of the cervical spine was absent in all patient at follow-up. Only one patient underwent surgery for the presenting symptoms of dysphagia. The other patients were treated conservatively. The authors examined 9 patients directly; these patients had bony fusion and did not complain of neck pain, except for a patient with traumatic spondylolisthesis.

Conclusions

Extension teardrop fracture of the axis is generally caused by hyperextension of the cervical spine caused by a direct high-energy blow to the forehead or mandible. Based on the present case study, the authors believe that osteopenia and older age should not be considered risk factors. Most patients with an extension teardrop fracture of the axis can be treated conservatively, and surgical intervention may only be indicated for specific cases, such as those in which a patient presents with dysphagia or with other complicated fractures.

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Hidetoshi Matsukawa, Motoharu Fujii, Masaki Shinoda, Osamu Takahashi, Daisuke Yamamoto, Atsushi Murakata and Ryoichi Ishikawa

Object

It is well known that spontaneous intradural vertebral artery dissection (siVAD) is an important cause of nontraumatic subarachnoid hemorrhage (SAH). The factors that influence whether SAH develops, however, remain unclear. The aim of this study was to investigate whether clinical characteristics and imaging findings are different in patients with siVAD with SAH compared to those with siVAD without SAH.

Methods

The authors conducted a retrospective, single-institution study involving patients in whom siVAD developed with or without SAH, between July 2003 and November 2010. Univariate and multivariate analyses were performed to evaluate clinical characteristics and MR angiography findings. The vertebral-union-basilar angle (VUBA) was defined as the most acute angle between line of the basilar artery trunk and line of the vertebral angle (VA) at the vertebral union on 3D MR angiograms.

Results

Among 58 patients with siVAD, 21 developed SAH. The presence of siVAD and SAH was significantly associated with higher rates of current smoking (OR 13; 95% CI 3.6–38; p < 0.0001), dissection of the dominant VA (OR 9.2; 95% CI 2.5–19; p = 0.0004), and unruptured supratentorial nondissecting saccular aneurysms (OR 11; 95% CI 2.1–19; p = 0.0025), and the VUBA of the dominant VA was significantly larger (p < 0.0001, univariate analysis). Multivariate analysis showed that these differences were still significant (p < 0.05).

Conclusions

A larger VUBA of the dominant VA, the presence of unruptured supratentorial nondissecting saccular aneurysms, and current smoking may be factors that predict which patients with siVAD will develop SAH by dominant VAD.

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Hidetoshi Matsukawa, Masaki Shinoda, Motoharu Fujii, Osamu Takahashi, Daisuke Yamamoto, Atsushi Murakata and Ryoichi Ishikawa

Object

Previous studies have shown a relationship between a patient's stage of diffuse axonal injury (DAI) and outcome. However, few studies have assessed whether a specific lesion or type of corpus callosum injury (CCI) influences outcome in patients with DAI. The authors investigated the effect of various DAIs and CCIs on outcome in patients with traumatic brain injury (TBI).

Methods

The authors retrospectively reviewed 78 consecutive patients with DAI who were seen between May 2004 and March 2010. Outcome was evaluated using the Extended Glasgow Outcome Scale (EGOS) 1 year after TBI. Patients with single DAIs had only 1 of the 3 lesions (lobar, CC, or brainstem). Patients with dual DAIs had 2 of these lesions, and those with triple DAIs had all of these lesions. Furthermore, the authors defined single, dual, and triple CCIs by using 3 lesions (genu, body, splenium) in the same way among patients with single (CC) DAIs. Univariate and multivariate logistic regression analyses were performed to evaluate the relationships between these lesions and outcome in patients with DAI.

Results

Fifty patients had single DAIs: 34 in the lobar area, 11 in the CC, and 5 in the brainstem. Twenty had dual DAIs, and 8 had triple DAIs. Of the 11 CCIs, 9 were single and 2 were dual CCIs. Among these lesions, only those in the genu were related to disability. The authors dichotomized patients into those with and without genu lesions, regardless of other injuries. Multinomial logistic regression analysis showed that a genu lesion (OR 18, 95% CI 2.2–32; p = 0.0021) and a pupillary abnormality (OR 14, 95% CI 1.6–24; p = 0.0068) were associated with disability (EGOS ≤ 6) in patients with DAI.

Conclusions

Regardless of the number of lesions, the existence of a genu lesion suggested disability 1 year after TBI in patients with DAI.

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Hidetoshi Matsukawa, Masaki Shinoda, Motoharu Fujii, Osamu Takahashi, Atsushi Murakata, Daisuke Yamamoto, Sosuke Sumiyoshi and Ryoichi Ishikawa

Object

Intraventricular hemorrhage (IVH) is widely regarded as one element of a complex involving severe blunt traumatic brain injury (TBI); corpus callosum injury (CCI) is recently considered to be one factor associated with poor outcome in patients with TBI. Although postmortem studies have focused on the relationship between IVH and CCI, there have been few investigations of IVH evidenced on CT scans as a predictor of CCI evidenced on MRI.

Methods

The authors retrospectively reviewed prospectively collected data from 371 patients with blunt TBI, without trauma to the face, chest, abdomen, extremities, or pelvic girdle, requiring immediate therapeutic intervention. Their aim was to investigate whether IVH found on CT predicts CCI on MRI. Clinical and radiological data were collected between June 2003 and February 2011. First, the authors classified patients into groups of those with CCI and those without CCI, and they compared clinical and radiological findings between them. Then, they investigated prognostic factors that were related to the development of disability at 6 months after injury. The outcomes at 6 months after injury were evaluated using the Extended Glasgow Outcome Scale (GOS-E). Finally, the authors evaluated the correlation between the severity of the IVH on CT and the number of CCI lesions on MRI. The severity of the IVH was defined by the number of ventricles in which IVH was seen, and the number of CCI lesions was counted on the MRI study.

Results

On multivariate logistic regression analysis, Glasgow Coma Scale score less than 9 (OR 2.70 [95% CI 1.10–6.27]), traffic accident (OR 2.59 [95% CI 1.37–4.93]), and IVH on CT (OR 3.31 [95% CI 1.25–8.49]) were significantly related to CCI. Multivariate analysis also showed that older age (p = 0.0001), male sex (OR 3.26 [95% CI 1.46–8.08], p = 0.0065), Glasgow Coma Scale score less than 9 (OR 8.27 [95% CI 3.39–21.4], p < 0.0001), evidence of IVH on CT (OR 4.09 [95% CI 1.45–11.9], p = 0.0081), and evidence of CCI on MRI (OR 8.32 [95% CI 3.89–18.8], p < 0.0001) were associated with future development of disability (GOS-E score ≤6). Furthermore, simple regression analysis revealed the existence of a strong correlation between the severity of IVH and the number of CCI lesions (r = 0.0668, p = 0.0022).

Conclusions

The authors' results suggest that evidence of IVH on CT may indicate CCI, which can lead to disability in patients with isolated blunt TBI.