Role of Bedside Transcranial Ultrasonography in the Assessment of Cerebral Hemodynamics in Decompressive Craniectomy Patients with Cranioplasty: A Single Centre Experience

Abstract

Intracerebral hemorrhage is a leading cause of death and disability worldwide. After intracerebral hemorrhage, cerebral blood flow (CBF) becomes extremely low approaching ischemic thresholds. Concurrently, CBF velocities become strongly correlated to CBF itself post-injury. Identification of such hemodynamic disturbances can be used to predict outcome immediately post-injury when indices are measured using transcranial doppler ultrasonography (TCD). TCD permits non-invasive assessment of different CBF velocities as well as pulsatility index (PI). Abnormal measurement of such indices is believed to correlate to poor outcome. To investigate the effect of cerebral hemodynamics after cranioplasty in decompressive craniectomy patients using pre and postoperative TCD. This study is a prospective study of 3 years duration undertaken on 64 patients. All the patients were evaluated by TCDbefore and after decompressive craniectomy.All patients were evaluated by transcranial Doppler (TCD) 1 week before and 7-15 days after cranioplasty. TCD results were obtained though trans-temporal approach. Statistically significant differences between the values before and after craniectomy were detected in Peak Systolic Volume (PSV) for the Anterior Cerebral Artery (ACA) (P = 0.001), in PSV for the Middle Cerebral Artery (MCA) (P < 0.004), in Mean Bloodflow Velocity (MV) for the MCA (P < 0.003), and in PSV for the Posterior Cerebral artery (PCA) (P = 0.001) on the ipsilateral side. There were statistically significant differences between the values before and after cranioplasty in PSV for the PCA (P = 0.004), on contralateral side.After decompressive craniectomy, the PI values for the MCA decreased, on average, to 31+/- 33% of the pre-surgical value in the treated side and to 28+/- 31% on the opposite side. On the other hand, the mean PI values for the extracranial ICA reduced to 34+/- 21% of the initial values in the treated side, and to 21+/- 31% on the opposite side.Cranioplasty improved CBF velocities in all major intracrainal arteries, not only on the side of the lesion adjacent to the cranioplasty, but also in distant regions, such as in the contralateral hemisphere. Decompressive craniectomy significantly improves cerebral hemodynamics both on ipsilateral and contralateral cerebral hemispheres.Concomitantly, PI values on TCD decrease significantly postoperatively, mainly in the decompressed cerebral hemisphere, indicating reduction in cerebrovascular resistance. We conclude that cranioplasty improves neurological status and the mechanism of postoperative improvement of neurological status may be due to increased CBF velocity.