Critique of “Assessment of Midline Shift in Post-decompressive Craniectomy Patients in Neurocritical Care: Comparison between Transcranial Ultrasonography and Computerized Tomography”

We read with interest the prospective comparison of transcranial sonography (TCS) with computerized (CT) in the assessment of midline shift in post-decompressive craniectomy patients in India by Maramattom et al.[1] The authors measured midline shift on TCS using the midpoint of the third ventricle as the reference, but the same on CT was measured using septum pellucidum between frontal horns as a standard. Because different regions of the brain may have different degrees of shift from midline, a more accurate assessment would have been possible had the same reference point been used for both TCS and CT. It is well-known that the presence of air hampers assessment by sonography, while air is not a limitation for CT. The air below the surgical flap is common in the first few days after surgery. The authors have neither quantified the number of patients, especially in the immediate postoperative period, in whom CT was performed, but the corresponding TCS was of poor diagnostic quality, nor the minimum postoperative interval required before a TCS of good diagnostic quality can be acquired. It is well-known that the morphology of the flap changes with a change in the position of the patient’s head. CT is usually performed in the true supine position, with rotation of head close to 0°. The methodology adopted by the authors does not make it clear whether TCS was performed in a similar position, without which there would be a significant measurable change in the position of intracranial structures, and subsequently the measured midline shift. Although TCS is an attractive radiation-free, portable, bedside alternative to CT for assessment of midline shift, the diagnostic accuracy of TCS needs further careful evaluation because of the reasons mentioned by vide supra. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.