I have read with great interest the recent paper of Masuoka et al. about a novel technique for microvascular decompression published in Neurosurgical Review 2011 [6]. The author provided a sling technique to transpose the culprit by means of stitching the offending artery to the tentorium or petrous dura. Regardless that several authors have reported the analogous retraction technique [4, 8], this paper focused on the stitching point anatomically. Although it is an alternative to separate the neurovascular confliction, this technique is not good enough to be propagated for it has numerous drawbacks.

First of all, this stitched sling retraction technique complicates the operation. It is not easy to complete those procedures of passing the thread around the artery and then stitching and knotting in such a small surgical field, which evidently adds extra operative time and the chance of complications. Meanwhile it might be a question if this thread-stitched fixation of the artery could maintain permanently without escape. Moreover, this thin sling thread may knife and harm the adventitia with pulsation or even occlude the artery. On the other hand, this technique is not suitable for multiple offending vessels including veins and arterioles, which is commonly encountered during the microvascular decompression (MVD) surgery [3, 14].

Secondly, this technique has some potential risks. It is not all visible while an angled needle go through the vessels. A blind manipulation means dangerous. Despite an appropriate spot has been localized by the author, it needs special skill to stitch on. A burst might be inevitable at the moment when the needle was penetrating the tentorium or the petrous dura, which is harmful to the meticulous microsurgery. Besides, when the surgeon concentrates on knotting or clipping, those surrounding delicate structures, especially petrosal veins as well as facial and vestibulocochlear nerves, are actually in jeopardy. In addition, the spatula has been seen in each figure of the paper. Nowadays, it has been the common view that a successful MVD can be achieved without a retractor [7]. However, to finish these extra procedures, it still has to be employed in order to obtain an additional operative room. It added risk coefficient compared with the non-retractor technique.

I agree with the author that the “transposition” is better than “interposition”. Anyway, it would not cause a new compression to the nerve as long as the offending vessel is thoroughly freed before a soft wadding of teflon was placed. As a matter of fact, the offending vessel is separated from the nerve by an ample opening of the surrounding arachnoids rather than merely squeezing in the teflon between them [5, 11–13]. The teflon actually plays a role of preventing the vessel from rebounding rather than in isolation. Therefore, the teflon has not necessarily to be placed at the conflict site—it could be put anywhere which it cause minimal pressure to the nerve.

With the experience of more than 2,000 cases of MVDs in our center, we have realized that a satisfactory manipulative space could be established without spatula retraction. The suffered nerve could be successfully decompressed without retraction of the offending vessel [1–3, 5, 9–13]. Here are some knacks:

  1. 1.

    The head of the patient should be turned back slightly to the ipsilateral side in the lateral decubitus position, which allows the cerebellum to droop under its own gravity without using the spatula.

  2. 2.

    The craniectomy should be lateral enough and as close as possible to the sigmoid sinus, which offers a maximal visual angle.

  3. 3.

    The surgical field is established by sufficient opening of the arachnoids rather than solely retracting the cerebellum.

  4. 4.

    A proper approach facilitates the operation.

    1. (a)

      For glossopharyngeal cases, it should be approached infracerebellarly.

    2. (b)

      For hemifacial cases, it should be approached infrafloccularly. The dissection should be medial enough to expose the pontomedullary fissure, where is usually haunted by the neurovascular conflict.

    3. (c)

      For trigeminal cases, the laterocerebellar (Fig. 1) rather than infratentorial approach is recommended, which avoids those blocking petrosal veins [10].

      Fig. 1
      figure 1

      a This was a left trigeminal neuralgia case. Instead of the superior cerebellar approach, the lateral cerebellar approach was chosen, which avoid those petrosal veins (PV). The superior cerebellar artery (SCA) was identified as the culprit, which adhered to trigeminal nerve (V) rostrally. b. With the surrounding arachnoids being sharply opened, the offending artery (SCA) was freed thoroughly. A soft wadding of teflon (T) was placed between the pons and the artery, which withdrew the offending vessel far away from the nerve (V) and no teflon was needed at the conflict site (asterisk)

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  5. 5.

    The decompression should be completed by fully releasing the offending vessel instead of stuffing teflon.

  6. 6.

    A soft teflon wadding should be adapted, which could be placed outside the conflict site.

  7. 7.

    The intraoperative electrophysiological monitoring is helpful to identify the offending vessel for hemifacial spasm cases (Fig. 2).

    Fig. 2
    figure 2

    a This was a left hemifacial spasm case. After the dura was opened, the anterior infracerebellar artery (AICA) was found to adhere to the petrous bone tightly (asterisk), which hindered the exposure. b With arachnoid opening, the lateral segment of vestibulocochlear nerve (VIII) was revealed, which seemed to contact with the posterior infracerebellar artery (PICA) caudally. But the real time electromyography did not monitor any change in the abnormal muscle response (AMR) wave after the PICA was transposed. Actually, the facial nerve was not visualized by then. c The microscopic view was moved caudally. With the arachnoids between the PICA and the caudal cranial nerves (XI, X) being opened sharply, the cerebellum was raised furthermore and the medial segment of facial nerve (VII) was visible. The nerve was discovered to be compressed by the proximal PICA at the site (number sign) where it originated from the brainstem. As soon as the artery was dissected free from the nerve, the AMR vanished. A tortuous vertebral artery (VA) was also observed ventrally to the caudal nerves, which pushed the PICA towards the facial nerve. d To effectively decompress the facial nerve, the VA was mobilized caudolaterally before manipulation of the direct offending artery (PICA). e With the VA being removed, the interposition of soft teflon waddings (T) was started from the level of those caudal nerves and gradually extended towards the facial nerve (VII). In this way, a satisfactory decompression was achieved without pulling the offending artery by a sticked sling, which was impossible for this case since the operative space was too limited because of the attached AICA

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