Ming-Xing Liu

Effectiveness and safety of microvascular decompression surgery for treatment of trigeminal neuralgia: a systematic review.

Abstract Microvascular decompression has been now accepted worldwide as a reasonable treatment for trigeminal neuralgia, yet, as a functional operation in the cerebellopontine angle, this process may be risky and the postoperative outcomes might not be good enough sometimes. To assess the effectiveness and safety of microvascular decompression for treatment of trigeminal neuralgia, we conducted a systematic review. Using the keywords “trigeminal neuralgia”, “microvascular decompression”, or “neurovascular conflict”, manuscripts published in English-language journals and indexed in PubMed between January 1, 2000 and June 1, 2013 on the treatment of trigeminal neuralgia (TN) with microvascular decompression were considered for this study. The success and complications were analyzed. The success in this investigation was defined as complete pain free. Continuous outcomes were summarized using means or medians, and dichotomous outcomes were presented as percentage associated with 95% confidence interval. Twenty-six papers with 6,847 patients were finally enrolled in this review. Among them, the male-to-female ratio was 1:1.4, the left-to-right ratio was 1:1.6, and the pain was located in the innervation of V3 and/or V2 in most of the cases with only 2.3% (0.1–4.7) of V1 exclusively. The average age at surgery was 60.9 years (52.5–64.1) with TN symptoms duration of 24.7 months (6.1–42.1) before microvascular decompression (MVD). Operative findings confirmed the superior cerebellar artery, anterior inferior cerebellar artery, posterior inferior cerebellar artery, and multiple vascular contacts (including veins) as the most common sources of nerve compression. The average follow-up duration was 35.8 months (26.2–56.6). The success rate was 83.5% (79.6–89.1). Complications included incisional infection in 1.3% (0.1–2.5), facial palsy 2.9% (0.5–6.2), facial numbness 9.1% (1.3–19.6), cerebrospinal fluid leak 1.6% (0.7–2.5), and hearing deficit 1.9% (0.2–3.9). The postoperative mortality was 0.1% (0.02–0.2). Accordingly, MVD is the most effective treatment for patients with trigeminal neuralgia. An immediate pain free can be achieved by an experienced neurosurgeon with good knowledge of the regional anatomy. To avoid complications, each single step of the process cannot be overemphasized.

Delayed relief of hemifacial spasm after microvascular decompression.

AbstractMicrovascular decompression (MVD) has been accepted worldwide as a reasonable treatment for hemifacial spasm (HFS); however, resolution of the HFS is often gradual. To conclude the delayed relief rate of the MVD for the treatment of HFS, we conducted a systematic review. Using the keywords delayed relief, hemifacial spasm, or microvascular decompression, articles published in English-language journals and indexed in PubMed between June 1, 1994 and June 1, 2014 on the treatment of HFS with emphasis on delayed relief were considered for this study. Twelve articles with 2727 patients with HFS were finally enrolled in this review. Among all the patients, the ratio of male versus female was 1:2.7, and left versus right was 1:1.6. The average age at surgery was 52.5 years (49.1–55.9 y), with HFS symptom duration of 68.4 months (38.4–98.4 mo) before the surgery. The average follow-up duration was 49 months (6.4–121.6 mo). After examining all the patients, we obtained a mean postoperative success rate of 85.1% (76.5%–93.5%), but the success rate after the MVD immediately is only 71.8% (59.5%–84%). The mean rate of delayed relief was 25.4% (18.8%–37.1%). Approximately 13.1% (5.9%–19.7%) of the patients with symptom recurrence resorted to repeated MVD during the follow-up period. Accordingly, MVD is the most effective treatment for patients with HFS, but some of the patients may experienced delayed relief, which could be avoided if a thorough decompression of the facial nerve root had been obtained.

Upregulation of Nav1.8 in Demyelinated Facial Nerves Might be Relevant to the Generation of Hemifacial Spasm

Abstract Our previous studies demonstrated that the abnormal muscle response could vanish when the ipsilateral superior cervical ganglion was removed and reappear when norepinephrine was dripped at the neurovascular conflict site. Evidentially, we believed that the mechanism of hemifacial spasm should involve emersion of ectopical action potential in the compressed facial nerve fibers. As the action potential is ignited by ion channel opening, we focused on Nav1.8 that has been found overexpressed in peripheral nerve while damaged. In this study, Moller model was adopted, 20 Sprague-Dawley rats underwent drip of norepinephrine, and the abnormal muscle response wave was monitored in 14 rats. Antibodies against unique epitopes of the &agr; subunit of sodium channel isoforms were used to detect the Nav1.8 neuronal isoforms, and the immunohistochemistry showed strong staining in 13 rats, which were all in the abnormal muscle response positive group (P < 0.05). Accordingly, we concluded that the substance of hemifacial spasm is an ectopic action potential that emerged on the damaged facial nerve, which might be coupled by Nav1.8.

Cholesteatoma of cerebellopontine angle presented as trigeminal neuralgia.

Abstract Cholesteatoma in the cerebellopontine angle presented as trigeminal neuralgia are not common. Between 2010 and 2013, 12 such patients were operated on in our department. Those patients included 8 females and 4 males with an average age of 47.8 years. One patient was combined with the ipsilateral hemifacial spasm. Five patients had hypesthesia in the ipsilateral side of the face. During the surgery, a pearly sheen mass with boundary was found in the cerebellopontine angle, and the trigeminal root was buried in the tumor. The tumor was removed totally in all the cases. Afterwards, the trigeminal root was observed distorted in 5 and the offending vessel was finally distinguished in 9. Postoperatively, the symptoms were relieved in all the cases and no recurrence was found up to the 36-month period of follow-up. We believed that the etiology of secondary trigeminal neuralgia caused by cholesteatoma is still the neurovascular confliction; the only difference is that the offending vessel was pushed by the tumor instead of idiopathically. Sometimes, the offending artery may not be found after the tumor resection for it may have been transposed off while the tumor is being removed.

Management of Bilateral Hemifacial Spasm with Microvascular Decompression

BACKGROUND Bilateral hemifacial spasm (HFS) is very rare. The literature contains only 32 clinical reports. Although microvascular decompression (MVD) is widely accepted as effective therapy for HFS, the etiology and surgical treatment of bilateral HFS are seldom addressed. We report our experience with MVD for patients with bilateral HFS. METHODS This retrospective report included 10 patients with bilateral HFS. All patients underwent MVD 1 or 2 times and were followed for 5-92 months. The clinical data were retrospectively analyzed. The etiology and treatment strategies were discussed. RESULTS Spasm stopped completely on the operative side in all 10 patients. Symptoms on the other side also resolved in 3 patients, improved in 1 patient, and did not improve at all in 6 patients. Of the 6 patients with no improvement, 5 underwent another MVD on the contralateral side within 1 year and experienced relief of symptoms, and 1 patient refused the surgery. The neurovascular conflict was found in all the operations. During the follow-up period, no complications of hearing loss or facial palsy and no recurrence were observed. CONCLUSIONS Vascular compression was the cause of bilateral HFS in our patients, and MVD relieved the symptoms. Thus, we recommend MVD for patients with bilateral HFS. A crowded cerebellopontine angle space and easy attrition of the neurovascular interfaces may play important roles in the occurrence of bilateral HFS. For some patients, 1 MVD can resolve bilateral symptoms.

Teflon Might Be a Factor Accounting for a Failed Microvascular Decompression in Hemifacial Spasm: A Technical Note.

Background: Although Teflon is widely adopted for microvascular decompression (MVD) surgery, it has never been addressed for failure analysis. This study analyzed the reasons for failed MVDs with emphasis on the Teflon sponge. Methods: Among the 685 hemifacial spasm cases between 2010 and 2014, 31 were reoperated on within a week because of unsatisfactory outcome, which was focused on in this study. Intraoperative findings regarding Teflon inserts of these repeat MVDs were reviewed. Results: Among the 38 without satisfactory outcomes, 31 underwent repeat MVDs, and they were all spasm free afterwards. Eventually, the final cure rate was 99.2%. It was found in the repeat MVDs that the failure was attributable to the Teflon insert in most of the cases (74.2%) directly or indirectly. It was caused by improper placement (47.8%), inappropriate size (34.8%) and unsuitable shape (17.4%) of the Teflon sponge. Conclusion: Although it is not difficult for an experienced neurosurgeon to discover a neurovascular conflict during the MVD process, the size, shape and location of the Teflon sponge should not be ignored. Basically, the Teflon insert is used to keep the offending artery away from the facial nerve root rather than to isolate it. Therefore, the ideal Teflon sponge should be just small enough to produce a neurovascular separation.

Treatment of postherpetic neuralgia using DREZotomy guided by spinal cord stimulation.

Background: Postherpetic neuralgia (PHN) is the most common complication following an episode of acute herpes zoster. The curative effect of current treatments is limited. Objectives: The purpose of this paper is to report a new treatment for PHN with a combination of dorsal root entry zone lesion (DREZotomy) and spinal cord stimulation (SCS). Methods: Microsurgical DREZotomy assisted with SCS for target localization was performed in 6 patients with PHN. A visual analog scale (VAS) was used to evaluate the pain pre- and postoperatively. Results: Except for 1 patient, in whom the test SCS was unsatisfactory, all patients finally underwent DREZotomy. These 5 patients experienced apparent symptom relief postoperatively, and the VAS score decreased from a baseline of 8.4 ± 1.14 to 2.4 ± 1.14 (p = 0.0020) and did not change significantly during the follow-up of up to 24 months. Conclusions: Microsurgical DREZotomy assisted with SCS for target localization is an effective remedy for PHN.

Bilateral hemifacial spasm might be cured by unilateral microvascular decompression.

Dear Editor, Despite hemifacial spasm and microvascular decompression (MVD) being well known today, bilateral hemifacial spasm has been seldom highlighted in the literature [2, 3, 5]. As the aetiology of bilateral hemifacial spasm remains controversial, most of the patients have been treated with prescription drugs or botulinum toxin injection [4, 6], which may relieve the symptoms in the early stage but do not cure the disease. We report the cases of nine patients with bilateral hemifacial spasm who underwent MVD in our depar tment . Interestingly, their contralateral spasm also stopped in three patients and improved in one, while the ipsilataral symptom disappeared completely after the one-side MVD. For the remaining five patients without contralateral improvement, four of them had another MVD in the other side within 1 year and the symptom relieved after the second MVD. During the follow-up period, no hearing loss, facial palsy or recurrence was observed. How could one-side MVD solve the bilateral symptoms? We assumed that the contralateral offending artery might also be transposed while the ipsilateral offending artery was removed. As the cerebellar arteries were communicated by the basilar artery, a little transposition of the basilar artery might lead to a separation of neurovascular contact. It has been reported that the abnormal muscle response (AMR) could have disappeared before the neurovascular conflict was discovered, because those procedures (e.g. suction of cerebrospinal fluid or retraction of cerebellum, etc.) may cause the offending artery to detach from contact with the facial nerve root [8, 9]. Our recent studies regarding the mechanism of hemifacial spasm demonstrated that the precondition for generating this hyperexcitability was attrition of the neurovascular interfaces due to mutual friction with pulsation, and neurotransmitters released from sympathetic ends in the adventitia of the offending vessel may trigger an ectopic action potential in these injured nerve fibres [1, 7, 10]. Therefore, even a little transposition may separate the artery from the nerve, which could stop the neurotransmitter spreading onto the nerve.

Retraction Note to: Anterior Cervical Discectomy and Fusion with a Compressive C-JAWS Staple

This chapter has been retracted at the request of the author in agreement with the editor. The article has been already accepted by a journal, and it can be searched in pubmed: Xia L, Liu MX, Zhong J. et al. Anterior cervical discectomy & fusion with a compressive staple of C-JAWS [J]. British Journal of Neurosurgery. 2016, Jun 22:1–5. Retraction Note to: Anterior Cervical Discectomy and Fusion with a Compressive C-JAWS Staple

One-Pot Aqueous Synthesization of Near-Infrared Quantum Dots for Bioimaging and Photodynamic Therapy of Gliomas

BACKGROUND As the early detection and total destruction of gliomas are essential for longer survival, we attempted to synthesize a quantum dot (QD) that is capable of recognizing glioma cells for imaging and photodynamic therapy. METHODS Using a one-pot aqueous approach, near infrared-emitting CdTe was produced. After detection of its physicochemical characteriistics, it was conjugated with RGD. The emission images were observed with confocal microscopy. To test its toxicity, CdTe-RGD at various concentrations was separately added to a human glioma cell line (U251) and a mouse embryo fibroblast cell line (3T3) (control) for incubation in dark conditions. To test its photodynamic effect, the U251 and 3T3 cells were then irradiated for 5-60 min, using a 632.8-nm laser. RESULTS This QD (Φ = 3.75 nm, photoluminescence (PL) peak wavelength = 700 nm, photoluminescence quantum yield (PLQY) = 20 %), was a spherical crystal with excellent monodispersity. Under a confocal microscope, U251 cells were visualized, but not the 3T3 cells. In dark conditions, the survival rates of both U251 and 3T3 cells were above 85 %. After laser irradiation, the survival rate of U251 cells decreased to 37 ± 1.6 % as the irradiation time and the CdTe-RGD concentration were increased. CONCLUSIONS With good physicochemical characteriistics and low toxicity, this QD-RGD has broad prospects for use in the biomedical imaging and photodynamic therapy of gliomas.