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Toshiaki Ueno, Brandon R. Macias, William T. Yost and Alan R. Hargens

✓ Elevated intracranial pressure (ICP) is a major factor associated with incidences of morbidity and mortality in patients with neurological disorders. The use of conventional methods for ICP monitoring is currently limited to patients with severe neurological conditions because of the methods' invasive nature. The authors have developed an ultrasonic device capable of monitoring ICP waveforms noninvasively by using a pulsed phase lock loop (PPLL) technique. The PPLL device records skull movement (several meters) associated with ICP pulsations. The purpose of this study was to correlate PPLL waveforms with invasively measured ICP waveforms in patients at the University of California San Diego Medical Center (13 patients).

A linear regression analysis revealed a high correlation between PPLL waveforms and invasively measured ICP waveforms during the same time domain (r2 = 0.88). A coherence function analysis, which provides the fractional portion of the mean square value at the output that is contributed by the input at a certain frequency, showed medium to high correlations (r2 = 0.50–0.90) between PPLL waveforms and invasively measured ICP waveforms at each harmonic wave components. Furthermore, there was a significant correlation (r2 = 0.680, p < 0.01) in the harmonic distortion ratio (an index representing how much a given waveform is distorted from a pure sine wave) between PPLL waveforms and invasively measured ICP waveforms. In conclusion, PPLL technology enables the noninvasive evaluation of ICP dynamics in clinical settings.

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Narihide Shinoda, Osamu Hirai, Shinya Hori, Kazuyuki Mikami, Toshiaki Bando, Daisuke Shimo, Takahiro Kuroyama, Yoji Kuramoto, Masato Matsumoto and Yasushi Ueno

OBJECTIVE

The presence of disproportionately enlarged subarachnoid space hydrocephalus (DESH) on brain imaging is a recognized finding of idiopathic normal pressure hydrocephalus (iNPH), but the features of DESH can vary across patients. The aim of this study was to evaluate the utility of MRI-based DESH scoring for predicting prognosis after surgery.

METHODS

In this single-center, retrospective cohort study, the DESH score was determined by consensus between a group of neurosurgeons, neurologists, and a neuroradiologist based on the preoperative MRI findings of the patients with suspected iNPH. The DESH score was composed of the following 5 items, each scored from 0 to 2 (maximum score 10 points): ventriculomegaly, dilated sylvian fissures, tight high convexity, acute callosal angle, and focal sulcal dilation. The association between the DESH score and improvement of the scores on the modified Rankin Scale (mRS), iNPH Grading Scale (iNPHGS), Mini–Mental State Examination (MMSE), Trail Making Test-A (TMT-A), and Timed 3-Meter Up and Go Test (TUG-t) was examined. The primary end point was improvement in the mRS score at 1 year after surgery, and the secondary outcome measures were the iNPHGS, MMSE, TMT-A, and TUG-t scores at 1 year after surgery. Improvement was determined as improvement of 1 or more levels on mRS, ≥ 1 point on iNPHGS, ≥ 3 points on MMSE, a decrease of > 30% on TMT-A, and a decrease of > 10% on TUG-t.

RESULTS

The mean DESH score for the 50 patients (mean age 77.6 ± 5.9 years) reviewed in this study was 5.58 ± 2.01. The mean rate of change in the mRS score was −0.50 ± 0.93, indicating an inverse correlation between the DESH score and rate of change in the mRS score (r = −0.749). Patients who showed no improvement in mRS score tended to have a low DESH score as well as low preoperative MMSE and TMT-A scores. There were no differences in the areas of deep white matter hyperintensity and periventricular hyperintensity on the images between patients with and without an improved mRS score (15.6% vs 16.7%, respectively; p = 1.000). The DESH score did differ significantly between patients with and without improved scores on the iNPHGS (6.39 ± 1.76 vs 4.26 ± 1.69, respectively; p < 0.001), MMSE (6.63 ± 1.82 vs 5.09 ± 1.93; p = 0.010), TMT-A (6.32 ± 1.97 seconds vs 5.13 ± 1.93 seconds; p = 0.042), and TUG-t (6.48 ± 1.81 seconds vs 4.33 ± 1.59 seconds; p < 0.001).

CONCLUSIONS

MRI-based DESH scoring is useful for the prediction of neurological improvement and prognosis after surgery for iNPH.

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Toshiaki Bando, Yasushi Ueno, Narihide Shinoda, Yukihiro Imai, Kazuhito Ichikawa, Yoji Kuramoto, Takahiro Kuroyama, Daisuke Shimo, Kazuyuki Mikami, Shinya Hori, Masato Matsumoto and Osamu Hirai

Pineal parenchymal tumor of intermediate differentiation (PPTID) is rare. The WHO first classified PPTID in 2000 as a pineal parenchymal tumor (PPT) with an intermediate prognosis between pineocytoma (PC) and pineoblastoma (PB). It is considered an intermediate-grade tumor and divided into WHO grade II or III.

The number of available reports about PPTID is presently limited, and the appropriate management for this tumor has not yet been determined.

The authors report a rare case of PC in a 63-year-old woman who presented with lower-extremity weakness and gait disturbance. A pineal mass lesion was detected on MRI. A diagnosis of PC was established after microsurgical gross-total tumor resection, and the patient received no adjuvant therapy after surgery. Two years after surgery, a partial recurrence was recognized and Gamma Knife radiosurgery was performed. Fours years later, the patient developed diffuse leptomeningeal dissemination. She was successfully treated with craniospinal irradiation. Leptomeningeal dissemination may develop 6 years after the initial diagnosis of PC. A histopathological study of the recurrent tumor revealed a malignant change from PC to PPTID.

The present case shows the importance of long-term follow-up of patients with PPTs following resection and the efficacy of craniospinal irradiation in the treatment of leptomeningeal dissemination.

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Takamitsu Fujimaki, Jae-Hyun Son, Shigehiko Takanashi, Teruyuki Ishii, Kazuhide Furuya, Toshihiro Mochizuki, Toshiaki Ueno and Tadayoshi Nakagomi

✓The authors report on their technique for preserving the lesser occipital nerve (LON) during lateral suboccipital craniotomy. In their technique, the LON, which runs along the surface of or just beneath the sternocleidomastoid muscle, is identified and preserved. Lesser occipital nerve preservation using their technique was attempted in 25 patients who underwent microvascular decompression for hemifacial spasm. The LON was successfully preserved in 16 of these patients, was impossible to preserve in two patients, and could not be identified in seven patients. Among the patients in whom LON preservation was successful, 87.5% were free of sensory disturbance 6 months after surgery, whereas both patients in whom the LON could not be preserved complained of sensory disturbances in the occipital area and the posterior part of the auricula. Fifty-seven percent of the patients whose LON could not be identified complained of sensory disturbance. Thus, this technique for preserving the LON reduces the incidence of sensory disturbance in the occipital region after suboccipital craniotomy for microvascular decompression for hemifacial spasm.