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Yasuhiro Chiba and Kenji Yuda

✓ A simple method is presented for detecting the patency of ventriculoperitoneal shunts with a pair of small disc thermistors. In an experimental model, the equipment detected definite temperature changes along the shunt tube. The extent of the temperature difference was proportional to the flow velocities, ranging from 5 to 60 ml/hr (120 to 1440 ml/24 hrs). A clinical study consisted of 26 trials in 23 hydrocephalic children and 10 trials in nine adult patients with normal-pressure hydrocephalus. Three of the 26 trials in the children were unsuccessful because of patient irritability and lack of cooperation. All trials for adult patients were successful. In all 25 patients, whose clinical pictures suggested functioning shunt, accurate confirmation of shunt patency was obtained. In six patients whose clinical pictures suggested questionable shunt function, this method revealed that all shunts were patent, and computerized tomography and follow-up clinical data supported this finding. In two patients whose clinical pictures suggested shunt malfunction, there was no indicator deflection, and shunt obstruction was proved at operation. This method is effective in checking shunt function, is simple, and may be repeated at frequent intervals.

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Yasuhiro Chiba, Yusuke Ishiwata, Noriyuki Suzuki, Masato Muramoto and Yumiko Kunimi

✓ A simple method is described for checking the patency of ventriculoperitoneal shunts by using a pair of small disc thermistors. With this technique, shunt patency is shown by a downward deflection of the recording trace, blockage of the ventricular catheter is indicated by a flat-line recording, and obstruction of the distal end of the abdominal catheter is demonstrated by an upward deflection. These observations were confirmed in a study of 32 hydrocephalic patients with obstructed shunts who subsequently underwent shuntography and operation. An experimental model was also devised to study the mechanism of the recording changes.

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Yasuhiro Chiba, Hiroshi Takagi, Fumoto Nakajima, Satoshi Fujii, Takao Kitahara, Saburo Yagishita and Yoji Itoh

✓ Three cases are presented in which a rare complication occurred after a shunt operation for hydrocephalus. On postoperative computerized tomography (CT) scans, extensive low-density areas appeared in the white matter along the ventricular catheter. After shunt revision, gradual resolution or disappearance of the low-density area was clearly demonstrated on CT. In one patient, a collection of cerebrospinal fluid (CSF) was confirmed at operation and appeared to lie in the extracellular spaces of the white matter. The phenomenon is considered to be localized CSF edema, different from porencephaly.

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Yusuke Ishiwata, Yasuhiro Chiba, Toshinori Yamashita, Gakuji Gondo, Kaoru Ide and Takeo Kuwabara

✓ Surface cooling and thermistor recording over shunt tubing was used in 23 studies of cerebrospinal fluid shunt patency in 19 patients with lumboperitoneal shunts and normal-pressure hydrocephalus. Shunt patency was shown by downward reflection of the recording trace similar to that obtained for ventriculoperitoneal shunts. Obstruction was demonstrated by a flat-line recording or an upward deflection.

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Hiroshi Kanno, Yasuhiro Chiba, Yoshikazu Kyuma, Akimune Hayashi, Hiroyuki Abe, Hiroto Takada, Ilu Kim and Isao Yamamoto

✓ Epidermal growth factor (EGF) content in urine from patients with glial tumors was examined by radioimmunoassay techniques with labeled human EGF and its rabbit EGF polyclonal antibody. There was no cross-reaction with transforming growth factor-α, which has a common receptor with EGF. Forty glial tumors were divided into three groups according to the clinical stage: Samples from Group A patients were obtained before therapy and/or after biopsy; in these patients a large volume of tumor was apparent on computerized tomography (CT). Group B samples were obtained after gross total removal of the tumor and/or chemo- and radiation therapy; these patients showed a small volume of residual tumor on CT. Samples from Group C patients were obtained after gross tumor total removal and/or chemo- and radiation therapy; no tumor was detected on CT scans in these patients. Urinary EGF levels in Group A samples were statistically significantly higher than in samples from healthy individuals (p < 0.001), Group B patients (p < 0.10), and Group C patients (p < 0.02). In addition, high-grade glial tumors in Group A cases showed a significantly higher level of urinary EGF than low-grade tumors in Group A patients (p < 0.05), or patients with meningioma (p < 0.02), metastatic brain tumor (p < 0.05), and cerebral infarction (p < 0.001). Longitudinal changes of urinary EGF levels in glioma patients mostly synchronized with the clinical course and therapeutic interventions. Therefore, urinary EGF, as a glial tumor marker, may be of practical value for diagnosing a malignant glioma and evaluating for the efficacy of chemo- and radiation therapy.

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Kyongsong Kim, Toyohiko Isu, Yasuhiro Chiba, Daijiro Morimoto, Seiji Ohtsubo, Mitsuo Kusano, Shiro Kobayashi and Akio Morita

Superior cluneal nerve (SCN) entrapment neuropathy is a known cause of low back pain. Although surgical release at the entrapment point of the osteofibrous orifice is effective, intraoperative identification of the thin SCN in thick fat tissue and confirmation of sufficient decompression are difficult. Intraoperative indocyanine green video angiography (ICG-VA) is simple, clearly demonstrates the vascular flow dynamics, and provides real-time information on vascular patency and flow. The peripheral nerve is supplied from epineurial vessels around the nerve (vasa nervorum), and the authors now present the first ICG-VA documentation of the technique and usefulness of peripheral nerve neurolysis surgery to treat SCN entrapment neuropathy in 16 locally anesthetized patients. Clinical outcomes were assessed with the Roland-Morris Disability Questionnaire before surgery and at the latest follow-up after surgery.

Indocyanine green video angiography was useful for identifying the SCN in fat tissue. It showed that the SCN penetrated and was entrapped by the thoracolumbar fascia through the orifice just before crossing over the iliac crest in all patients. The SCN was decompressed by dissection of the fascia from the orifice. Indocyanine green video angiography visualized the SCN and its termination at the entrapment point. After sufficient decompression, the SCN was clearly visualized on ICG-VA images. Low back pain improved significantly, from a preoperative Roland-Morris Questionnaire score of 13.8 to a postoperative score of 1.3 at the last follow-up visit (p < 0.05). The authors suggest that ICG-VA is useful for the inspection of peripheral nerves such as the SCN and helps to identify the SCN and to confirm sufficient decompression at surgery for SCN entrapment.

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Yasuhiro Chiba, Toyohiko Isu, Kyongsong Kim, Naotaka Iwamoto, Daijiro Morimoto, Kazuyoshi Yamazaki, Masaaki Hokari, Masanori Isobe and Mitsuo Kusano

OBJECT

Superior cluneal nerve (SCN) entrapment neuropathy (SCNEN) is a cause of low-back pain (LBP) that can be misdiagnosed as a lumbar spine disorder. The clinical features and etiology of LBP remain poorly understood. In this study, 5 patients with intermittent LBP due to SCNEN who had previously received conservative treatment underwent surgery. The findings are reported and the etiology of LBP is discussed to determine whether it is attributable to SCNEN.

METHODS

Intermittent LBP is defined as a clinical condition in which pain is induced by standing or walking but is absent at rest. Between April 2012 and March 2013, 5 patients in this study who had intermittent LBP due to SCNEN underwent surgery. The patients included 3 men and 2 women, with a mean age of 66 years. The affected side was unilateral in 2 patients and bilateral in 3 (total sites, 8). The interval from symptom onset to treatment averaged 51.4 months; the mean postoperative follow-up period was 17.6 months. The clinical outcomes were assessed using the numerical rating scale (NRS) for LBP, the Japanese Orthopaedic Association (JOA) scale, and the Roland-Morris Disability Questionnaire (RDQ) preoperatively and at the last follow-up; these data were analyzed statistically.

RESULTS

None of the 5 patients reported LBP at rest. Intermittent LBP involving the iliac crest and buttocks was induced by standing or walking an average of 136 m. In 2 patients with unilateral involvement, LBP was improved only by SCN block. Surgeries were performed on 6 sites in 5 patients because the SCN block was only transiently effective. Patients’ SCNs penetrated the orifice of the thoracolumbar fascia. SCN kinking at the orifice was exacerbated at the lumbar-extension provocation posture, and radiating pain increased upon manual intraoperative compression of the SCN in this posture. After releasing the SCN surgically, disappearance of the pain was intraoperatively confirmed by manual compression of the SCN with the patients in the lumbar-extension posture. Surgery was effective in all 5 patients, and all clinical outcome scores indicated significant improvement (p < 0.05).

CONCLUSIONS

To the authors’ knowledge, this is the first report of patients with intermittent LBP due to SCNEN. Clinical and surgical evidence presented suggests that their LBP was exacerbated by lumbar extension and that symptom relief was obtained by SCN block or surgical release of the SCN entrapment. These results suggest that SCNEN should be considered as a causal factor in patients for whom walking elicits LBP.