Bone temperature elevation by drilling friction and neurological outcome in the cervical spino-laminoplasty

Background

Drill-induced heat has been suspected as a cause of tissue injury, and there are ample experimental data to substantiate the implication. However, no clinical results have been presented with measurement of temperature in the vicinity of neural structures during the actual spinal procedures.

Methods

Using a thermocouple, temperature in the gutters drilled in the midline and the lateral margins of the lamina was monitored closely in 61 patients, who underwent the French-door style of cervical spino-laminoplasty. The drilling was performed intermittently for a duration of 5 or 10 seconds, using 3- or 5-mm diamond burrs with sufficient continuous cooling irrigation. The correlations between bone temperature elevation and postoperative sensorimotor symptoms were then analyzed.

Results

In the lateral gutters at the most cephalad level (typically C3), where the drilling was performed underneath an overlying bundle of muscle attached to C2's spinous process, the temperature rose significantly. This occurred even with 5-second drilling sessions. The average peak temperature was 44 °C at this level. At all other sites, the temperature was maintained below 40 °C. In three patients, transient neurological deficit developed postoperatively, which did not correlate with the incidence of bone temperature elevation.

Conclusions

Intermittent drilling with sufficient irrigation can prevent thermal neuronal damage generated by high-speed drills. Drilling with small diamond burrs in deep and narrow spaces covered by overlying muscles predisposes to inadequate irrigation and thermal elevation. Continuous, protracted drilling without frequent irrigation may result in excessive heat generation and nerve injury.     

Incisional Intercostal Hernia With Prolapse of the Colon After Right Partial Nephrectomy

A 75-year-old woman with a history of myocardial infarction, gallstones, and right renal cancer was referred to our department because of right flank pain. She had a surgical scar on the right abdomen between the 10th and 11th ribs; computed tomography demonstrated intercostal herniation of the colon. Recognizing the possibility of adhesions of the hernia and colon, we used a median skin incision and patched a polyester mesh coated with absorbent collagen. The patient had an uneventful postoperative course, with no pain for 6 months postoperatively. Transdiaphragmatic intercostal hernias with abdominal contents commonly develop after trauma or thoracic surgery. Incisional intercostal hernias seldom develop after nephrectomy; the present case is only the fourth report. We conjecture that a costochondral incision can induce subluxation of the costotransverse joint, intercostal nerve injury, and atrophy of the intercostal and abdominal oblique muscles. Surgeons must therefore recognize the potential, albeit rare, for intercostal hernia after nephrectomy.     

Enhancement of Hemocompatibility of the MERA Monopivot Centrifugal Pump: Toward Medium‐Term Use

The MERA monopivot centrifugal pump has been developed for use in open‐heart surgery, circulatory support, and bridge‐to‐decision for up to 4 weeks. The pump has a closed‐type, 50‐mm diameter impeller with four straight paths. The impeller is supported by a monopivot bearing and is driven by a radial‐flux magnet‐coupling motor. Because flow visualization experiments have clarified sufficient pivot wash and stagnation at the sharp corner of the pivot support was suggested, sharp corners were removed in the design stage. The index of hemolysis of the pump operating at more than 200 mm Hg was found to be lower than that of a commercial pump. Four‐week animal tests were then conducted two times; improvement of thrombus formation was seen in the female pivot through modification of female pivot geometry. Overall antithrombogenicity was also recorded. Finally, to assure mid‐term use, an additional 4‐week durability test revealed that the rate of the axial pivot wear was as small as 1.1 µm/day. The present in vitro and in vivo studies revealed that the MERA monopivot centrifugal pump has sufficient hemocompatibility and durability for up to 4 weeks.     

Desirable training and roles of Japanese endoscopists towards the further penetration of endoscopic submucosal dissection in Asia

Endoscopic submucosal dissection (ESD) was invented in Japan and is now permeating into the rest of the world. Therefore, it is necessary to elucidate the desirable ESD training by knowing the current status of ESD training in Japan. After this, we mainly discussed the following three topics: (i) requirements for preceptees to start ESD training; (ii) requirements for competent endoscopists in ESD; and (iii) requirements for preceptors in the first half of the upper gastrointestinal tract session at the Endoscopic Forum Japan 2011. Additionally, we discussed what Japanese endoscopists can do for further permeation of ESD outside Japan, especially in Asia in the second half. The session was wrapped up by the conclusions that it was absolutely necessary to establish official training courses authorized by the Japan Gastroenterological Endoscopy Society with certification for trainees and trainers and our Japanese endoscopists had a responsibility to spread ESD safely and reliably by collaborating with enthusiastic endoscopists in each country which have different backgrounds in terms of incidences and screening systems of target diseases, accessibility to endoscopy, medical economics, national characters, and so on.     

Benidipine reduces ischemia reperfusion-induced systemic oxidative stress through suppression of aldosterone production in mice

Aldosterone is implicated in the pathogenesis of several cardiovascular diseases, including ischemia reperfusion (I/R) and myocardial infarction, and also causes oxidative stress and inflammation in cardiovascular systems. Benidipine, a long-acting T- and L-type calcium channel blocker, reduces infarct size following myocardial I/R in rabbits. Benidipine also inhibits the production of aldosterone in vitro. However, the precise mechanism of this phenomenon in vivo remains unknown. We therefore evaluated whether benedipine has a beneficial role through the regulation of oxidative stress in myocardial I/R. C57BL/6J mice were subjected to 30?min of left ascending coronary I/R. Benidipine was administered orally at 3?mg?kg(-1) daily for 3 weeks without any changes in hemodynamic variables. Benidipine significantly reduced infarction size (13.4±2.5%) compared with controls (25.5±3.6%). Urinary 8-hydroxy-2' deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, increased significantly after I/R. I/R induced increases in 8-OHdG were significantly lower with benidipine. Local myocardial 8-OHdG was also elevated in I/R, but this augmentation was significantly suppressed with benidipine. The plasma aldosterone concentration (PAC) significantly increased 2 days after I/R and remained elevated at least 7 days after I/R. Treatment with benidipine significantly decreased I/R-induced elevation of the PAC. I/R-induced markers of fibrosis in hearts also reduced in benidipine. These results suggest that the administration of benidipine reduces myocardial infarct size as well as systemic oxidative stress after I/R. These phenomena are partially linked to reduced plasma aldosterone levels.