LAUSR

Dear Editor and Colleagues: Thank you very much for your attention and valuable comments on our previous article entitled “Reoperation after failed microvascular decompression for glossopharyngeal neuralgia”. After reading the comments raised by our colleagues carefully, we have read through our previous article, which would be specifically mentioned as ARTICLE in the following paragraph and surveyed the latest relevant literature. Here, we will make the following response to the letter. Among the 8 cases in the ARTICLE, the latest operation was done in 2018. We have made a telephone follow-up recently, of which the longest follow-up period of 9 years and the shortest 2 years; the overall postoperative result was good. Most of the reoperations after MVD in our center were focused on patients with hemifacial spasm (HFS). The glossopharyngeal nerve root should be exposed during MVD for HFS; according to the available data, the main risk steps are (1) dissecting the adhesion between cerebellum and dura beneath the original bone window; (2) separating the blood vessels around the glossopharyngeal nerve; and (3) removing the original decompressive materials [7, 8]. For patients with recurrent HFS and glossopharyngeal neuralgia after MVD underwent reoperation in our center, no serious complications such as intracranial hematoma, infection, and cerebellar hemisphere infarction were found, and the overall risk was low. Vagoglossopharyngeal rhizotomy (VGR) has been mentioned in the fourth paragraph of discussion of the ARTICLE. All the patients underwent laryngoscope exam before the reoperation. In a recent survey of 87 patients with glossopharyngeal neuralgia in our department, we have found that although VGR resulted in lower postoperative quality of life due to a high complication rate, most of these complications were mild. The overall satisfaction rates of VGR or MVD for glossopharyngeal neuralgia were similar [3, 5]. Radiotherapy can be used as an alternative for recurrent glossopharyngeal neuralgia after MVD, with the advantages of noninvasive and repeatable [4]. Similar to radiofrequency therapy, the mechanism of radiotherapy is to sacrifice part of nerve function for pain relief, and the efficacy is dose-dependent. In addition, there is risk of delayed radiation-induced nerve injury. The long-term efficacy and complication of radiotherapy varied between different literature reports [1, 2, 6, 9], which is also mentioned in the discussion part of the ARTICLE. “The transposition method should be tried to prevent further recurrence of symptoms, especially for the offending vertebral artery with a strong rebound and pulsatile force.” We agree with this point of view; we have also done several cases of offending vessel transposition in difficult decompression situation. We believe that the difficulty and risk of transposition are higher than that of interposition. The transposition operation is generally aimed at vessels of larger diameter, and the hemodynamic changes may occur when the blood vessel is suspended far away from the original position, and there is the possibility of vessel angulation, to cause the risk of ischemia. In addition, these vessels may have small branches supplying the cerebellum and brainstem, which may be damaged during transposition. The biomedical glue sling technique may of some risk; we have made some improvements based on past experience. First, bipolar electrocoagulation was used to cauterize the dura of the skull base where the vascular loop was to be fixed, and then, the larger autologous fascia or Teflon was pasted on the dura with biomedical glue; the offending vessels were wrapped with muscle fascia; and then, the fascia was pasted onto the autologous fascia above mentioned. If the position of the offending vessel is not ideal, This article is part of the Topical Collection on Functional Neurosurgery Pain