Hong Hj

Postoperative changes in paraspinal muscle volume: comparison between paramedian interfascial and midline approaches for lumbar fusion.

In this study, we compared the paramedian interfascial approach (PIA) and the traditional midline approach (MA) for lumbar fusion to determine which approach resulted in the least amount of postoperative back muscle atrophy. We performed unilateral transforaminal posterior lumbar interbody fusion via MA on the symptomatic side and pedicle screw fixation via PIA on the other side in the same patient. We evaluated the damage to the paraspinal muscle after MA and PIA by measuring the preoperative and postoperative paraspinal muscle volume in 26 patients. The preoperative and postoperative cross-sectional area, thickness, and width of the multifidus muscle were measured by computed tomography. The degree of postoperative paraspinal muscle atrophy was significantly greater on the MA side than on the contralateral PIA side (-20.7% and -4.8%, respectively, p<0.01). In conclusion, the PIA for lumbar fusion yielded successful outcomes for the preservation of paraspinal muscle in these 26 patients. We suggest that the success of PIA is due to less manipulation and retraction of the paraspinal muscle and further studies on this technique may help confirm whether less muscle injury has positive effects on the long-term clinical outcome.

Neuroprotective effect of ginseng total saponins in experimental traumatic brain injury.

In the present study, we investigated whether ginseng total saponins (GTSs) protect hippocampal neurons after experimental traumatic brain injury (TBI) in rats. A moderate-grade TBI was made with the aid of a controlled cortical impact (CCI) device set at a velocity of 3.0 m/sec, a deformation of 3.0 mm, and a compression time of 0.2 sec at the right parietal area for adult male Sprague-Dawley rats. Sham-operated rats that underwent craniectomy without impact served as controls. GTSs (100 and 200 mg/kg) or saline was injected intraperitoneally into the rats immediately post-injury. Twenty-four hours after the injury, the rats underwent neurological evaluation. Contusion volume and the number of hippocampal neurons were calculated with apoptosis evaluated by TUNEL staining. 24 hr post-injury, saline-injected rats showed a significant loss of neuronal cells in the CA2 region of the right hippocampus (53.4%, p<0.05) and CA3 (34.6%, p<0.05) compared with contralateral hippocampal region, a significant increase in contusion volume (34±8 µL), and significant increase in neurologic deficits compared with the GTSs groups. Treating rats with GTSs seemed to protect the CCI-induced neuronal loss in the hippocampus, decrease cortical contusion volume, and improve neurological deficits.

Neurochemical Characterization of the TRPV1-Positive Nociceptive Primary Afferents Innervating Skeletal Muscles in the Rats.

OBJECTIVE Transient receptor potential vanilloid subfamily type 1 (TRPV1), a most specific marker of the nociceptive primary afferent, is expressed in peptidergic and non-pepetidergic primary afferents innervating skin and viscera. However, its expression in sensory fibers to skeletal muscle is not well known. In this study, we studied the neurochemical characteristics of TRPV1-positive primary afferents to skeletal muscles. METHODS Sprague-Dawley rats were injected with total 20 microl of 1% fast blue (FB) into the gastrocnemius and erector spinae muscle and animals were perfused 4 days after injection. FB-positive cells were traced in the L4-L5 (for gastrocnemius muscle) and L2-L4 (for erector spinae muscle) dorsal root ganglia. The neurochemical characteristics of the muscle afferents were studied with multiple immunofluorescence with TRPV1, calcitonin gene-related peptide (CGRP) and P2X(3). To identify spinal neurons responding to noxious stimulus to the skeletal muscle, 10% acetic acids were injected into the gastrocnemius and erector spinae muscles and expression of phospho extracellular signal-regulated kinase (pERK) in spinal cords were identified with immunohistochemical method. RESULTS TRPV1 was expressed in about 49% of muscle afferents traced from gastrocnemius and 40% of erector spinae. Sixty-five to 60% of TRPV1-positive muscles afferents also expressed CGRP. In contrast, expression of P2X(3) immnoreaction in TRPV1-positive muscle afferents were about 20%. TRPV1-positive primary afferents were contacted with spinal neurons expressing pERK after injection of acetic acid into the muscles. CONCLUSION It is consequently suggested that nociception from skeletal muscles are mediated by TRPV1-positive primary afferents and majority of them are also peptidergic.