Introduction Primary trigeminal neuralgia is a common functional neurosurgical disorder, and for drug-refractory trigeminal neuralgia, microvascular decompression is currently the most effective and safe surgical approach. Traditionally, it was believed that only arterial compression in the REZ of the trigeminal nerve root could cause trigeminal neuralgia, but an increasing number of clinical studies have confirmed that arteries are not the only vessels responsible for trigeminal neuralgia, and not all compression sites occur in the REZ. This enriches the traditional theory of microvascular compression. Failure to have a clear understanding of these types of responsible vessels may result in intraoperative omission of the responsible vessels, which can seriously affect the outcome of the procedure. Common responsible vessels for primary trigeminal neuralgia The most common responsible vessels for primary trigeminal neuralgia are the superior cerebellar artery, followed by the anterior inferior cerebellar artery, mixed arteriovenous compression, simple veins, posterior inferior cerebellar artery, and vertebrobasilar artery. Types of responsible vessels The traditional view is that the responsible vessels are arteries only, and the site of compression is in the REZ zone of the trigeminal nerve root. Many reports in the current literature confirm that there are various types of responsible vessels for trigeminal neuralgia. According to the source of the responsible vessel, it can be divided into arterial type, venous type and mixed type (mixed arterial and venous compression), among which arterial type is the main type; according to the site of the responsible vessel compression, it can be divided into brain stem end compression type, brain pool segment compression type and mixed type, among which brain stem end compression is the main type; according to the number of responsible vessels, it can be divided into single branch compression type and multiple branch compression type, among which single branch compression is the main type. How to avoid intraoperative omission of the responsible vessels The correct determination and treatment of the responsible vessels is the key to ensure the efficacy of surgery. Recognizing the various types of responsible vessels mentioned above can help to correctly determine the responsible vessels. The trigeminal nerve root from the brainstem to Meckel’s capsule should be fully explored during surgery, and the suspected veins should not be missed in addition to the arteries. Key points 1. The common responsible vessels for trigeminal neuralgia are arteries, but there are also cases of mixed venous and arteriovenous compression. 2.The common site of compression of the responsible vessel is the brainstem end, but there are also brain pool segment compression and multiple compressions. 3.The whole trigeminal nerve root should be explored comprehensively during the operation to avoid missing the responsible vessels including the veins. In the case of multiple compressions, as it is difficult to determine which vessel is the responsible vessel intraoperatively, all of them should be dealt with as much as possible. Blind spots 1.Mistake that only arteries are responsible for trigeminal neuralgia and that veins do not cause trigeminal neuralgia, resulting in the omission of responsible vessels during surgery. 2.Mistakenly thinking that only the compression of the trigeminal nerve root REZ area can cause trigeminal neuralgia, and neglecting the exploration of the whole trigeminal nerve root.