Causal Effect Estimation on Imaging and Clinical Data for Treatment Decision Support of Aneurysmal Subarachnoid Hemorrhage.

Aneurysmal subarachnoid hemorrhage is a serious medical emergency of brain that has high mortality and poor prognosis. Treatment effect estimation is of high clinical significance to support the treatment decision-making for aneurysmal subarachnoid hemorrhage. However, most existing studies on treatment decision support of this disease are unable to simultaneously compare the potential outcomes of different treatments for a patient. Furthermore, these studies fail to harmoniously integrate the imaging data with non-imaging clinical data, both of which are significant in clinical scenarios. In this paper, the key challenges we address are: how to effectively estimate the treatment effect for aneurysmal subarachnoid hemorrhage; and how to utilize multi-modality data to perform this estimation. Specifically, we first propose a novel scheme that uses multi-modality confounders distillation architecture to predict the treatment outcome and treatment assignment simultaneously. Notably, with these distilled confounder features, we design an imaging and non-imaging interaction representation learning strategy to use the complementary information extracted from different modalities to balance the feature distribution of different treatment groups. We have conducted extensive experiments using a clinical dataset of 656 subarachnoid hemorrhage cases, which was collected from the Hospital Authority of Hong Kong. Our method shows consistent improvements on the evaluation metrics of treatment effect estimation, achieving state-of-the-art results over strong competitors. Code is released at https://github.com/med-air/TOP-aSAH.

A Factorial Analysis on Visual Outcomes of Transsphenoidal Surgery for Pituitary Macroadenoma.

Objective Sellar lesions are possible reversible causes of vision loss. This study is to provide quantitative objective measurement of efficacy of surgery for non-functioning pituitary adenoma and discuss different factors that could affect visual outcome of non-functioning pituitary adenoma. Method This is a single centre, retrospective study conducted at a tertiary neurosurgery referral centre. 108 cases of sellar tumors which underwent surgery during the 3-year period from early June 2015 to late May 2018 were reviewed. Pituitary adenoma that were non-functioning and without apoplexy at initial presentation were selected for the study. We have analyzed the correlation of different factors with the visual outcome, including the extent of vertical decompression in terms of change in tumor height post operation and the extent of lateral decompression in terms of change in Knosp grading. Visual outcome was represented by the visual impairment score (VIS), an integrated measurement of visual acuity and visual field deficit. Results Preoperative absolute tumor height and supracarotid height correlated with preoperative VIS scale ( p ≤ 0.01). Absolute Knosp grading correlates significantly with VA ( p = 0.001) and VF ( p ≤ 0.001) of that particular eye. Although most patients had an objective improvement in visual acuity (VA) (88%) and visual field (VF) (99%) after operation, a larger reduction in tumor height and successful Knosp downgrading after surgery is associated with better VIS improvement. ( p = 0.025) Change in supracarotid height shows trend in correlating with change in VIS ( p = 0.084). Conclusion Height of tumor measured from genu of cavernous ICA correlates better with visual outcome than absolute tumor height. The extent of both vertical and lateral decompression of non-functioning pituitary adenoma are important determinants that lead to better visual outcome. As endoscopic approach is able to achieve a greater degree of lateral decompression, it is a preferred approach in pituitary surgery to achieve a better visual outcome.

Minimally Invasive Tubular Retractor Surgery for Intradural Extramedullary Spinal Tumor Reduces Postoperative Degeneration of Paraspinal Muscle.

Background Minimally invasive surgery (MIS) using a tubular retractor has been increasingly utilized in spinal surgery for degenerative conditions with the benefit of paraspinal muscle preservation. This benefit has not been previously reported for intradural extramedullary tumors using the MIS approach. In this study, we aimed to compare the degree of postoperative fatty degeneration in paraspinal muscle between MIS with tubular retractor (MIS) and open laminectomy (Open) for intradural extramedullary spinal tumors. Methods This was a retrospective review conducted in a tertiary neurosurgical center from 2015 to 2019. The degree of paraspinal muscle fatty degeneration, as measured by Goutallier grade on postoperative magnetic resonance imaging (MRI), was analyzed, and the degree of excision, tumor recurrence rate, and chronic pain were compared between the two surgical approaches. Results Among 9 patients in the MIS group and 33 patients in the Open group, the rate of gross total resection was comparable (MIS: 100.0%, Open: 97.0%, p = 1.000). The degree of paraspinal muscle fatty degeneration was significantly reduced in the MIS group (median Goutallier grade 1 in MIS group vs. median Goutallier grade 2 in Open group, p = 0.023). There was no significant difference in the tumor recurrence rate, complication rate, and chronic pain severity. A consistent trend of reduced analgesic consumption was observed in the MIS group, though not statistically significant. Conclusions Minimally invasive tubular retractor surgery is an effective approach for appropriately selected intradural extramedullary spinal tumors with significantly reduced postoperative fatty degeneration in paraspinal muscle.

Neurocognitive recovery and global cerebral perfusion improvement after cranioplasty in chronic sinking skin flap syndrome of 18 years: Case report using arterial spin labelling magnetic resonance perfusion imaging.

Sinking skin flap syndrome (SSFS) is a complication among long-term survivors of stroke or traumatic brain injury treated by decompressive craniectomy. The syndrome encompasses a wide spectrum of neurological symptoms including cognitive decline, seizures, speech and sensorimotor deficits. Early cranioplasty appears to improve cerebral perfusion, but the efficacy of cranioplasty in neurocognitive outcome in long-standing SSFS patient is unclear. We report a 64-year-old patient who suffered from traumatic brain injury and underwent decompressive craniectomy 18 years ago. She had chronic SSFS with pre-cranioplasty assessments demonstrating severe neurocognitive impairments which were static over time. After cranioplasty with custom-made polyetheretherketone flap to restore the 264 cm2 skull defect, magnetic resonance perfusion scan with pseudo-continuous arterial spin labelling technique showed a two-fold augmentation of cerebral blood flow in both frontal lobes, as well as areas distal to the sunken skin flap compared to baseline. This is accompanied by improvement of neurocognitive function as assessed by Montreal Cognitive Assessment, Neurobehavioral Cognitive State Examination, and Rivermead Behavioural Memory Test three and six months after cranioplasty. The patient's quality of life and that of her primary carer also showed improvement. This report describes a case of neurocognitive and global cerebral perfusion improvement after cranioplasty in the setting of prolonged SFSS of 18 years, and adds to the growing body of literature supporting the therapeutic role of cranioplasty beyond purely protective or cosmetic indications. The advantages and clinical utility of pCASL MR perfusion in assessing serial CBF before and after cranioplasty is illustrated.

Use of subdural drain for chronic subdural haematoma? A 4-year multi-centre observational study of 302 cases.

Chronic subdural haematoma (CSDH) is a common neurosurgical condition and is more prevalent in the ageing population. Studies have suggested that placement of subdural drains after burr-hole drainage was associated with lower recurrence rates. However, a considerable proportion of surgeons remained unconvinced of the effectiveness of drain placement and concerns exist with the potential complications this additional manoeuvre entails such as infection or bleeding. The aim of the present study is to evaluate the impact of subdural drain on CSDH recurrence and its safety. This is a multicentre observational study. Data of consecutive patients with burr-hole drainage performed for CSDH in three hospitals in Hong Kong during a four-year period from January 2008 to December 2011 were prospectively collected and retrospectively analysed. The primary outcome was symptomatic recurrence requiring re-operation. Secondary outcomes included the modified Rankin scales (mRS), morbidity and mortality at six months. A total of 302 patients were identified. The recurrence rate was 8.72% (13/149) with drain placement versus 16.3% (25/153) with no drain (Odds Ratio=0.489, 95%CI 0.240-0.998; p=0.0463). Local wound infection, subdural empyema, acute subdural haematoma and other complications had no significant difference. Six-month mRS, 30-day mortality and six-month mortality were comparable in both groups. In conclusion, the use of subdural drain significantly reduced recurrence with no significant increase in complications.

Intra-arterial revascularization therapy for basilar artery occlusion-a systematic review and analysis.

Acute basilar artery occlusion has been managed aggressively with various modalities due to its potentially debilitating outcome. While intra-arterial mechanical thrombectomy with stentriever has established clear evidence for anterior circulation stroke with large vessel occlusion as an adjunct to intravenous thrombolysis or the sole modality in intravenous thrombolysis ineligible patients, similar high-level evidence was not available for intra-arterial mechanical thrombectomy of posterior circulation stroke with acute basilar artery occlusion. We hence perform a systematic review of current literature to compare intra-arterial pharmacological thrombolysis (IA-P) and intra-arterial mechanical thrombectomy (IA-MT) for acute basilar artery occlusion. Forty-one studies published between 1996 and 2015 were compared and studied by odds ratio analysis using Mantel-Haenszel risk ratio estimation, and time trend analysis using meta-regression. Patients in the IA-MT group were older, presented with more severe stroke, and more likely received treatment more than 12 h since onset of stroke. At 3 months, survival and clinical outcome were superior in the IA-MT group than the IA-P group, associated with higher recanalization rate. There were no difference between proportion of dependent survivors, and rate of symptomatic intracerebral hemorrhage across groups. Intra-arterial thrombolysis with mechanical devices led to improved survival, better short-term clinical outcome and higher recanalization rate than intra-arterial pharmacological thrombolysis.

Review and recommendations on management of refractory raised intracranial pressure in aneurysmal subarachnoid hemorrhage.

Intracranial hypertension is commonly encountered in poor-grade aneurysmal subarachnoid hemorrhage patients. Refractory raised intracranial pressure is associated with poor prognosis. The management of raised intracranial pressure is commonly referenced to experiences in traumatic brain injury. However, pathophysiologically, aneurysmal subarachnoid hemorrhage is different from traumatic brain injury. Currently, there is a paucity of consensus on the management of refractory raised intracranial pressure in spontaneous subarachnoid hemorrhage. We discuss in this paper the role of hyperosmolar agents, hypothermia, barbiturates, and decompressive craniectomy in managing raised intracranial pressure refractory to first-line treatment, in which preliminary data supported the use of hypertonic saline and secondary decompressive craniectomy. Future clinical trials should be carried out to delineate better their roles in management of raised intracranial pressure in aneurysmal subarachnoid hemorrhage patients.

The use of diffusion tensor tractography to measure the distance between the anterior tip of the Meyer loop and the temporal pole in a cohort from Southern China.

OBJECT: Anterior temporal lobe resection plus amygdalohippocampectomy can cause damage to the anterior portion of the optic radiation, also known as the Meyer loop, resulting in homonymous superior quadrantanopia. Magnetic resonance diffusion tensor tractography (DTT) of the Meyer loop can help in surgical planning. In this study, the distance of the anterior tip of the Meyer loop to the temporal lobe pole (ML-TP) in the Southern Chinese population was assessed. METHODS: The authors studied 16 Southern Chinese individuals (8 men and 8 women; mean age 45.6 years, range 21-60 years). Diffusion tensor images were obtained with a 3-T MR imaging system using a single-shot spin echo echo planar imaging sequence. Two trained operators, one neurosurgeon (Operator A) and one radiologist (Operator B), carried out the DTT analysis with software iPlan (BrainLAB) and FiberTrak (Philips). RESULTS: For the 32 temporal lobes, the intraclass correlation coefficient (ICC) of the 2 operators' results using iPlan was 0.96, while that of Operator A using iPlan and Operator B using FiberTrak was 0.75. The ICC of Operator B using iPlan and FiberTrak was 0.81. The ML-TP distance of normal lobes (30 lobes [2 lobes that previously underwent surgery were excluded]) was 36.3±5.5 mm (range 26.6-48.9 mm), 36.3±5.3 mm (range 26.8-48.2 mm), and 35.9±6.4 mm (range 20.8-48.4 mm) for Operator A using iPlan, Operator B using iPlan, and Operator B using FiberTrak, respectively (p>0.05). CONCLUSIONS: The 2 operators reached good agreement on ML-TP distance measurement using DTT. The DDT results can be more software dependent than operator dependent. The measurement with FiberTrak demonstrated larger range and standard deviation than measurement with iPlan.