In recent years, a new procedure known as the Dujiangyan-style superficial temporal artery–middle cerebral artery (STA–MCA) side-to-side anastomosis has begun to be used in the treatment of adult moyamoya disease.

Drawing on recent medical literature, this article explains the procedure's design, its potential advantages, the patients for whom it may be considered, and the questions that still require further study.

What is moyamoya disease, and why is revascularization surgery needed?

Moyamoya disease is a chronic cerebrovascular disorder in which major intracranial arteries progressively narrow and may eventually become occluded, reducing the blood supply to the brain. In response, numerous small and fragile collateral vessels develop. Their smoky appearance on angiography gave the disease its name.

As the disease progresses, patients may experience:

  • Transient ischemic attacks (TIAs)
  • Ischemic stroke
  • Intracranial hemorrhage
  • Limb weakness
  • Speech impairment
  • Cognitive decline

Revascularization surgery is an important treatment for improving cerebral perfusion and reducing stroke risk. Superficial temporal artery–middle cerebral artery (STA–MCA) bypass is one of the most widely used direct revascularization procedures.

What is the ‘Dujiangyan-style’ bypass?

Conventional STA–MCA bypass usually uses an end-to-side anastomosis, in which the end of the donor artery is connected to the side wall of a recipient cerebral artery.

The Dujiangyan-style technique described in the study uses a side-to-side anastomosis. The side walls of the donor and recipient arteries are joined while continuity of both vessels is preserved as far as possible.

The name does not refer to the location of the operation. It draws on the flow-diversion concept of China's Dujiangyan irrigation system.

Much like a system that preserves flow during dry periods and diverts excess water during high-flow periods, this design aims to let blood distribute more naturally in response to pressure changes, potentially reducing the risk created by a sudden postoperative increase in cerebral blood flow.

How is this technique intended to work?

After a conventional bypass, the newly established conduit may deliver a large amount of blood rapidly into brain tissue that has been chronically ischemic.

If the brain cannot immediately adapt to this change, cerebral hyperperfusion syndrome (CHS) may occur. Its manifestations can include:

  • Severe headache
  • Neurological deterioration
  • Seizures
  • Intracranial hemorrhage in severe cases

The Dujiangyan-style side-to-side anastomosis is designed to use hemodynamic principles to distribute blood more gradually. The study describes three main concepts:

1. Limiting an excessively rapid early increase in flow

By preserving part of the donor artery's flow-regulating pathway, the new blood supply entering the brain may increase more gradually.

2. Allowing excess blood to divert naturally

When intracranial pressure or resistance is relatively high, some blood can continue toward the distal superficial temporal artery and scalp vascular network instead of entering the brain in its entirety.

3. Reducing localized flow impact at the anastomosis

A flow path that more closely follows the natural direction of blood movement may reduce local turbulence and the potential for thrombus formation.

What potential benefits did the study report?

The study retrospectively analyzed 240 adults with moyamoya disease who underwent unilateral STA–MCA bypass. Of these, 197 received a Dujiangyan-style side-to-side anastomosis and 43 received a conventional end-to-side anastomosis. Baseline characteristics, including age, sex, and disease severity, were similar between the groups, providing a degree of comparability.

1. A significantly lower rate of postoperative cerebral hyperperfusion syndrome

This was the study's principal finding. CHS occurred in 3.6% of patients in the Dujiangyan-style group and 18.6% of those in the conventional end-to-side group, a statistically significant difference.

For patients, this suggests that the technique may lower the risk of complications associated with an abrupt postoperative increase in cerebral blood flow.

2. Neurological recovery was similar to that with the conventional technique

The investigators compared postoperative modified Rankin Scale (mRS) scores, a commonly used measure of neurological disability and functional outcome. Neurological recovery did not differ significantly between the two groups.

3. Similar bypass patency

DSA, CTA, and other examinations performed three months after surgery showed no significant between-group differences in bypass patency or Matsushima grade. The new technique therefore showed similar performance in maintaining an open bypass.

4. No significant increase in postoperative cerebral infarction or hemorrhage

The rates of postoperative cerebral infarction and intracranial hemorrhage did not differ significantly between the two groups. The available data did not indicate that the Dujiangyan-style technique increased these serious complications.

Which patients might be considered for this procedure?

The study mainly involved adults aged 18 years or older who met the Japanese diagnostic criteria for moyamoya disease and underwent STA–MCA bypass.

Whether the technique is appropriate for an individual patient also depends on:

  • The presence of cerebral ischemic symptoms
  • Cerebral perfusion study findings
  • Whether the donor and recipient vessels are suitable for anastomosis
  • The surgical team's technical experience
  • The patient's overall health

The procedure is therefore not suitable for every patient with moyamoya disease. Selection requires an individualized assessment by an experienced cerebrovascular neurosurgical team.

What does the operation generally involve?

In simplified terms, the surgeon selects the superficial temporal artery as the donor vessel and performs a precise microsurgical side-to-side anastomosis with a cortical branch of the middle cerebral artery. The distal continuity of the donor artery is preserved as far as possible. Intraoperative fluorescence angiography can be used to confirm blood flow, while postoperative CT perfusion, MRA, DSA, and related examinations assess recovery of cerebral perfusion and the status of the bypass. The study's operative photographs demonstrate creation of the side-wall arteriotomies, the anastomotic process, and the completed bypass.

Frequently asked questions (FAQ)

Q1: Is the Dujiangyan-style bypass better than a conventional bypass?

Current evidence suggests that it may reduce the risk of postoperative cerebral hyperperfusion syndrome, while neurological recovery and bypass patency appear similar to those achieved with the conventional technique. Determining which approach is more appropriate requires individualized medical assessment.

Q2: What is cerebral hyperperfusion syndrome (CHS)?

CHS is a postoperative complication caused by an excessively rapid increase in blood flow after cerebral perfusion is restored. It can cause headache, neurological deterioration, or seizures and, in severe cases, intracranial hemorrhage.

Q3: Is this operation suitable for every patient with moyamoya disease?

No. It has mainly been studied in adults with moyamoya disease. Suitability depends on vascular anatomy, disease characteristics, overall health, and evaluation by the treating neurosurgical team.

Reference

Hu, M., Du, S., Yu, J., Xin, C., Tao, T., Yang, X., Zhou, Y., Zhang, J., & Chen, J. (2026). Efficacy analysis of Dujiangyan-style superficial temporal artery–middle cerebral artery side-to-side anastomosis for adult moyamoya disease. Chinese Journal of Neurosurgery, 42(6), 566–571. https://doi.org/10.3760/cma.j.cn112050-20260122-00032

Medical note

This article is educational and cannot replace emergency care, diagnosis, or a formal physician-patient consultation. Acute neurological symptoms require immediate local emergency evaluation.