In Reply to the Letter to the Editor Regarding "Large Craniotomy Increases the Risk of Minor Perioperative Complications in Revascularization Surgery for Moyamoya Disease"

Longitudinal evaluation of cerebral perfusion evolution after revascularization surgery in moyamoya disease by CT perfusion

OBJECTIVE

To assess the longitudinal evolution of cerebral perfusion after revascularization surgery in patients with moyamoya disease (MMD) by CT perfusion (CTP).

MATERIALS AND METHODS

Thirty-one clinically confirmed MMD patients (12 males and 19 females, average age: 33.26 y, Suzuki stages 3 and 4: 19 and 11, respectively) who underwent revascularization surgery (bilateral (n=13) or unilateral (n=18)) were studied retrospectively. All patients underwent CTP examinations before and in the week after surgery and long-term (>3 months). CTP metrics (CBF, CBV, MTT, TTP, and delay TTP) were derived. The corresponding CTP metric values of the ROIs, which were manually drawn in the white matter (WM) and gray matter (GM), were recorded.

RESULTS

Six patients developed a new or progressive cerebral infarction/hemorrhage. In all patients, compared with the preoperative level, the TTP of GM and WM decreased in the short term after the surgery (P ≤ 0.005). Concurrently, the WM CBF increased significantly a week after surgery (P =0.02). However, in the long-term follow-up, the CBV and CBF in the GM and WM decreased to equal to or lower than the preoperative level, especially for CBV in the WM (P =0.012). Furthermore, cerebral perfusion began to decrease in the sixth month, and a continuous decline was observed over the next two months. It returned to the presurgical level after one year. In addition, the improvement in postsurgical perfusion was greater in Suzuki stage 3 patients than stage 4 patients.

CONCLUSION

Cerebral perfusion in patients with MMD improved shortly after surgery. However, in the long-term, brain perfusion decreased, most seriously in 6-8 months postoperatively, which might indicate that patients with MMD need timely follow-up and long-term intervention.

Impact of craniotomy area on improvement of cerebral blood flow in combined revascularization surgery for moyamoya disease

OBJECTIVE

To investigate factors associated with improvements in cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) after combined revascularization surgery for moyamoya disease, with special attention to the size of craniotomy.

METHODS

We retrospectively analyzed 35 hemispheres in 27 patients with adult and older pediatric moyamoya disease. CBF and CVR were measured separately in the MCA and ACA territories from acetazolamide-challenged single-photon emission computed tomography before and after 6 months postoperatively, and associations with various factors were analyzed.

RESULTS

Postoperative CBF improved in patients with lower preoperative blood flow in both ACA and MCA territories. Postoperative CVR improved in 32 of 35 patients (91.4%) in the MCA territory and in 30 of 35 patients (85.7%) in the ACA territory, with more prominent improvement in the MCA territory than in the ACA territory (MCA territory 29.7% vs ACA territory 21.1%, p = 0.015). Craniotomy area did not correlate with postoperative CBF and only MCA territory was associated with good (≥30%) CVR improvement (odds ratio 9.33, 95% confidence interval 1.91-45.6, p = 0.003).

CONCLUSIONS

Postoperative CBF improved in adult and older pediatric cases, reflecting preoperative CBF. Postoperative CVR improved in most cases, although the degree of improvement was more prominent in the MCA territory than in the ACA territory, suggesting a contribution of the temporal muscle. Large craniotomy area was not associated with improved blood flow in the ACA territory and should be applied prudently.

Investigation of the Effects of Large Bone Flap Craniotomy on Cerebral Hemodynamics, Intracranial Infection Rate, and Nerve Function in Patients with Severe Craniocerebral Trauma

In order to explore the clinical value of large bone flap craniotomy, the effects of standard large bone flap craniotomy on cerebral hemodynamic indexes, incidence of postoperative intracranial infection, and neurological function in patients with severe craniocerebral trauma are investigated. 89 patients with severe craniocerebral trauma admitted from January 2020 to June 2021 are analyzed retrospectively. All patients are divided into a large craniotomy group (n = 45) and control group (n = 44) according to different surgical methods. The large craniotomy group is treated with large craniotomy decompression, and the control group is treated with traditional craniotomy decompression. The incidence of intracranial infection in each group is recorded, and NIHSS is applied to observe the neurological function recovery of 2 groups before and 1 month after operation. Besides, the patients are followed up after surgery and the Kaplan-Meier survival curve is obtained to compare the survival rate of patients in the two groups. It is clearly evident that the two surgical methods have certain clinical efficacy in the treatment of patients with severe craniocerebral trauma. Comparatively, the large craniotomy can further improve brain blood supply and improve neurological function recovery. Also, it can obtain low incidence of postoperative adverse reactions and intracranial infection.