ObjectiveVertebral distraction is routinely performed during anterior cervical discectomy and fusion (ACDF). Overdistraction can injure the facet joints and may cause postoperative neck pain consequently. The purpose of this study was to investigate the clinical relevance of distraction force during ACDF.MethodsThis study included 24 consecutive patients with single level cervical disc disease undergoing single level ACDF. We measure the maximum torque just before the the arm of the Caspar retractor was suspended by the rachet mechanism by turning the lever on the movable arm using a torque meter. In order to turn the lever using the torque driver, we made a linear groove on the top of the lever. We compared the neck disability index (NDI) and visual analogue scale (VAS) scores between the high torque group (distraction force>6 kgf·cm) and the low torque group (distraction force≤6 kgf·cm) at routine postoperative intervals of 1, 3, 5 days and 1, 3, 6 months.ResultsThe VAS scores for posterior neck pain had a linear correlation with torque at postoperative 1st and 3rd days (y=0.99×-1.1, r2=0.82; y=0.77×-0.63, r2=0.73, respectively). VAS scores for posterior neck pain were lower in the low torque group than in the high torque group on both 1 and 3 days postoperatively (3.1±1.3, 2.6±1.0 compared with 6.0±0.6, 4.9±0.8, p<0.01). However, the difference in NDI scores was not statistically significant in all postoperative periods.ConclusionVertebral distraction may cause posterior neck pain in the immediate postoperative days. We recommend not to distract the intervertebral disc space excessively with a force of more than 6.0 kgf·cm.

PurposeThe anterior cingulate cortex (ACC) plays a critical role in the initiation, development, and maintenance of neuropathic pain. Recently, the effects of optical stimulation on pain have been investigated, but the therapeutic effects of optical stimulation on trigeminal neuralgia (TN) have not been clearly shown. Here, we investigated the effects of optical inhibition of the ACC on TN lesions to determine whether the alleviation of pain affects behavior performance and thalamic neuron signaling.Materials and methodsTN lesions were established in animals by generating a chronic constriction injury of the infraorbital nerve, and the animals received injections of AAV-hSyn-eNpHR3.0-EYFP or a vehicle (phosphate-buffered saline [PBS]) in the ACC. The optical fiber was fixed into the ipsilateral ACC after the injection of adeno-associated virus plasmids or vehicle. Behavioral testing, consisting of responses to an air puff and cold allodynia, was performed, and thalamic neuronal activity was monitored following optical stimulation in vivo. Optical stimulation experiments were executed in three steps: during pre-light-off, stimulation-light-on, and post-light-off states. The role of the optical modulation of the ACC in response to pain was shown using a combination of optical stimulation and electrophysiological recordings in vivo.ResultsMechanical thresholds and facial cold allodynia scores were significantly improved in the TN lesion group during optical stimulation compared to those in the control group. Thalamic neuronal activity, consisting of the firing rate (spikes/s) and burst rate (bursts/s), was also decreased during optical stimulation.ConclusionReciprocal optical inhibition of the ACC can alleviate pain-associated behavior and decrease abnormal thalamic sensory neuron activity in the trigeminal neuropathic rat model. The descending pain pathway can modulate thalamic neurons from the ACC following optical stimulation.

A sharp trigeminal-pontine angle on the affected side was found in idiopathic TN patients by FIESTA imaging. This suggests that a sharp trigeminal-pontine angle increases the chance of neurovascular compression on the medial side of the trigeminal nerve.

A 36-year-old female patient presented with shoulder pain experienced over a period of one year and progressive weakness in both legs for one month. A magnetic resonance imaging scan revealed an intradural extramedullary (IDEM) fusiform mass about 9.8 cm in length, heterogeneously enhanced at the level of C6-T4 with spinal cord compression. At the time of surgery, the surgeon found an encapsulated IDEM tumor with spinal root attachment. The tumor was completely resected and the histologic diagnosis revealed ependymoma. The patient showed a favorable outcome with no recurrence at the 6-month follow-up. This paper reports a rare case of intradural extramedullary ependymoma with spinal root attachment.

Although the hypothesis that small posterior fossa volume influences TN was feasible, we did not find any volumetric differences (including the cisternal and parenchymal volumes).However, small pontomesencephalic cistern volumes were more frequent in patients with TN.