CLINICAL ARTICLE J Neurosurg 128:229–235, 2018 The effect of cranioplasty following decompressive craniectomy on cerebral blood perfusion, neurological, and cognitive outcome Adnan Hussain Shahid, MS,1 Manju Mohanty, PhD,1 Navneet Singla, MCh,1 Bhagwant Rai Mittal, MD,2 and Sunil Kumar Gupta, MCh1 Departments of 1Neurosurgery and 2Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India OBJECTIVE Decompressive craniectomy is an established therapy for refractory intracranial hypertension. Cranio- plasty following decompressive craniectomy not only provides protection to the brain along with cosmetic benefits, but also enhances rehabilitation with meaningful functional recovery of potentially reversible cortical and subcortical dam- aged areas of the affected as well as the contralateral hemisphere. The aim of the study was to assess neurological and cognitive outcome as well as cerebral blood flow after cranioplasty. METHODS Thirty-four patients admitted for replacement cranioplasty after decompressive craniectomy for head injury were studied prospectively. Clinical, neurological, and cognitive outcomes were assessed by the Glasgow Outcome Scale (GOS), the Glasgow Coma Scale, and a battery of cognitive tests, respectively. Simultaneously, cerebral blood perfusion was assessed by technetium-99m ethyl cysteinate dimer (99mTc-ECD) brain SPECT imaging 7 days prior to and 3 months after cranioplasty. RESULTS Prior to cranioplasty 9 patients (26.5%) had GOS scores of 5 and 25 patients (73.5%) had GOS scores of 4, whereas postcranioplasty all 34 patients (100%) improved to GOS scores of 5. Approximately 35.3%–90.9% patients showed cognitive improvement postcranioplasty in various tests. Also, on comparison with brain SPECT, 94% of patients showed improvement in cerebral perfusion in different lobes. CONCLUSIONS Cranioplasty remarkably improves neurological and cognitive outcomes supported by improvement in cerebral blood perfusion. https://thejns.org/doi/abs/10.3171/2016.10.JNS16678 KEY WORDS cranioplasty; GOS; GCS; decompressive craniectomy; SPECT; cognitive outcome; trauma HE management of refractory intracranial hyperten- following decompressive craniectomy was previously sion remains a therapeutic challenge for the neuro- thought to be beneficial simply for protective and cosmetic surgeon. In modern-day neurosurgical practice, de- purposes. However, in recent years its role in improving Tcompressive craniectomy is often required in patients with cortical and subcortical functions as well as restoring CSF severe head injuries, middle cerebral artery infarctions, dynamics is increasingly being recognized.7,8,10,13–17,23, 27,37 and severe brain edema secondary to infective or neo- In addition, subcutaneously preserved autologous bone plastic processes.1,3,22 It has been proven that therapeutic flaps have been found to be more effective for cranioplasty decompressive craniectomy reduces mortality and mor- following decompressive craniectomy.30 Although clinical bidity rates in a significant proportion of patients if used improvement has been documented in several studies, pre- in appropriate settings, but it also can result in different and postcranioplasty neuropsychological assessment has symptomatologies like “syndrome of trephined,” altered been documented only in few studies, and most of them CSF hydrodynamics, and impairment in underlying cere- are case reports.2,11,12 A few studies have also documented bral perfusion.4,18, 19, 22, 25,29,31,32, 38,39 Restorative cranioplasty the role of increased cerebral blood perfusion (CBP) fol- ABBREVIATIONS CBF = cerebral blood flow; CBP = cerebral blood perfusion; COWAT = Controlled Oral Word Association Test; DSST = Digit Symbol Substitution Test; DST = Digit Span Test; GCS = Glasgow Coma Scale; GOS = Glasgow Outcome Scale; RAVLT-DR, RAVLT-IR = Rey Auditory Verbal Learning Test–delayed recall, RAVLT– immediate recall; TMT-A, TMT-B = Trail-Making Test, Parts A and B; 99mTc-ECD = technetium-99m ethyl cysteinate dimer. SUBMITTED March 18, 2016. ACCEPTED October 14, 2016. INCLUDE WHEN CITING Published online March 3, 2017; DOI: 10.3171/2016.10.JNS16678. ©AANS 2018, except where prohibited by US copyright law J Neurosurg Volume 128 • January 2018 229 Unauthenticated | Downloaded 10/07/21 05:12 AM UTC A. H. Shahid et al. lowing cranioplasty in improvement of patients’ function- Rey Auditory Verbal Learning Test ing.8,15, 37,40 In this investigation an attempt has been made The Rey Auditory Verbal Learning Test (RAVLT) is to study the effect of cranioplasty following decompres- a measure of verbal learning and memory. There are 2 sive craniectomy on CBP, and on neurological and cogni- lists, A and B, consisting of 15 words each. The number of tive outcome. words recalled correctly in the immediate recall (RAVLT- IR) trial, delayed recall (RAVLT-DR) trial, and the recog- Methods nition trial will form the memory score.28 This prospective observational study was conducted Digit Span Test in the Department of Neurosurgery, Postgraduate Insti- The Digit Span Test (DST) is a subtest of the PGI Mem- tute of Medical Education and Research, in Chandigarh, ory Scale, which is an Indian adaptation of the Wechsler India. After receiving approval from the Institute’s eth- Memory Scale, and it measures auditory attention and ics committee, 37 patients who had previously undergone working memory. The score will be the maximum number decompressive craniectomy following head injury were of digits recalled correctly.24 admitted for replacement cranioplasty between Janu- ary 2014 and September 2014. They were enrolled after Digit Symbol Substitution Test giving informed consent. Of the 37 patients recruited, 3 were lost to follow-up and were excluded from the study. The Digit Symbol Substitution Test (DSST) is a test of The demographic and clinical details at the time of in- mental speed, which requires motor persistence, sustained jury and after decompressive craniectomy (at time of dis- attention, and response speed. Rapid information process- ing is required to substitute the symbols accurately and charge) were recorded. There were 30 (88.2%) male and 4 36 (11.8%) female patients. The mean age was 31.53 ± 10.08 quickly. years, and mean educational level was 10.76 ± 2.93 years. For each test the raw scores obtained were compared Eleven (32.4%) patients had severe, 13 (38.2%) had mod- with normative data for the respective tests and then were erate, and 10 (29.4%) had mild head injury. The patients converted into either percentiles or Z scores. The patients with mild and moderate head injuries were initially man- scoring below the 15th percentile or below 1.5 SD were aged conservatively, and decompressive craniectomy was considered to have significant impairment in that specific done when they deteriorated after clinical and imaging domain. evidence of significant mass effect or herniation. At the 99m time of admission for cranioplasty, 16 patients (47.1%) Tc-ECD Brain SPECT Imaging had left, 17 (50.0%) had right, and 1 (2.9%) had bifrontal All the patients underwent technetium-99m ethyl cys- craniectomy defects. The median interval between crani- teinate dimer (99mTc-ECD) brain SPECT imaging. After ectomy and cranioplasty was 5 months, with a range of intravenous administration of the radiotracer (mean 700 3–29 months. Thirty-two patients underwent autologous MBq), brain SPECT acquisition started at 0.5–1 hour by bone graft placement and 2 underwent titanium plate cra- using a dual-head SPECT gamma camera (Symbia T16, nioplasty (due to autologous bone infection). All patients Siemens). The SPECT data were acquired over a 360° underwent neurological assessment, cognitive assessment, rotation (circular orbit) in 128 projections (20 seconds/ and SPECT imaging 1 week prior to and 3 months after projection) in a 128 × 128 matrix with a zoom factor of cranioplasty. 1.5. The acquired SPECT data were then reconstructed us- ing an iterative reconstruction algorithm and Butterworth Neurological Assessment smoothing filter. Subsequently, the reconstructed data Glasgow Coma Scale (GCS)35 and Glasgow Outcome were displayed in 3 planes (axial, sagittal, and coronal) for Scale (GOS) scores20 were used to assess the neurological visual localization and interpretation of the lesions dem- outcome. onstrating focal and abnormal uptake of the radiotracer. The SPECT data were analyzed using SCENIUM dedi- cated software for regional analyses of brain projections. Cognitive Assessment The minimum cerebral perfusion was calculated by the A battery comprising the following tests was used for SCENIUM dedicated application in the syngo (Molecular cognitive assessment. Imaging) application for regional analyses of brain pro- jections. This application measures minimum, maximum, Trail-Making A and B Test and mean perfusion within each lobe or region. The ra- The Trail-Making Test (TMT) is a measure of visuo- tio of minimum perfusion of all lobes was calculated and conceptual and visuomotor functions. It consists of 2 compared with postcranioplasty results. A change in ratio parts: part A measures visual attention and psychomotor by even 1% was considered an improvement.34 speed, and part B measures cognitive flexibility and task All the assessments were performed at 2 time points, switching.26 first at 1 week prior to cranioplasty and then at 3 months after cranioplasty. The cohort of patients was also divid- Controlled Oral Word Association Test ed into 2 groups according to the time interval