A Semi-Autonomous Stereotactic Brain Biopsy Robotic System With Enhanced Surgical Safety and Surgeon-Robot Collaboration.

OBJECTIVE: Despite benefits brought by recent neurosurgical robots, surgical safety and surgeon-robot collaboration remain significant challenges. In this article, we analyze and address these problems in the context of brain biopsy, by proposing a semi-autonomous system. METHODS: A robotic module is designed for the automation of all the brain biopsy procedures, and a biopsy cannula with tissue blocker is developed to avoid tissue excess and haemorrhage. In addition, two methods are proposed for surgical safety and surgeon-robot collaboration enhancement. First, a priority-based control framework is proposed for neuronavigation with simultaneous optical tracking line-of-sight maintenance and surgeon avoidance. Second, after neuronavigation, an adaptive reconfiguration method is developed to optimize the arm angle of KUKA robot based on the surgeon's pose, for workspace interference minimization, high robot dexterity, and joint-limit avoidance. RESULT: Effectiveness of the proposed solution demonstrated by simulations and experiments. CONCLUSION: The system can perform automatic navigation with simultaneous optical tracking maintenance and surgeon avoidance, autonomous brain biopsy, and adaptive reconfiguration for workspace interference minimization. SIGNIFICANCE: This work improves existing neurosurgical systems, in terms of autonomy level from mechanical guidance to task autonomy, surgical safety, and surgeon-robot collaboration.

Pre-operative cognitive burden as predictor of motor outcome following bilateral subthalamic nucleus deep brain stimulation in Parkinson's disease.

INTRODUCTION: The interrelationship between neurocognitive impairments and motor functions was observed in patients with advanced Parkinson's disease (PD). This study was conducted to identify pre-operative neurocognitive and clinical predictors of short-term motor outcome following subthalamic nucleus deep brain stimulation (STN-DBS). METHODS: All consecutive PD patients who were eligible for bilateral STN-DBS from 2009 to 2019 were evaluated before and at 1 year following surgery. Standard motor evaluation and neurocognitive tests including global cognition, memory, executive functions (attention and category fluency), confrontational speech, visuospatial abilities, and mood were conducted at baseline. The post-operative STN-DBS effects were assessed at 1 year following the surgery. Multiple regression analysis was applied to identify baseline independent predictors of post-operative STN-DBS effect. RESULTS: A total of 82 patients were analyzed. It was found that younger age at operation, higher levodopa responsiveness at baseline based on UPDRS-III total score, and better baseline verbal delayed memory and category fluency predicted post-operative motor outcome at 1 year following STN-DBS (F = 9.639, p < 0.001, R2 = .340). CONCLUSION: Our findings demonstrated the role of baseline cognitive burden, especially cognitive processes related to frontostriatal circuits, was significant clinical predictors of short-term motor outcomes following STN-DBS. Profile analysis of neurocognitive functions at baseline is recommended.

ABC/2 formula for "bedside" postoperative pneumocephalus volume measurement.

BACKGROUND: Postoperative pneumocephalus is associated with a higher risk of recurrence of chronic subdural hematoma (cSDH). However, there is no verified simple way to measure the pneumocephalus volume at the bedside for daily clinical use. The ABC/2 method was shown to be a simple and reliable technique to estimate volumes of intracranial lesions, such as intracranial hematomas. This study aims to evaluate the accuracy of the ABC/2 formula in estimating volumes of pneumocephalus, as compared to the gold standard with computer-assisted volumetric analysis. METHODS: A total of 141 postoperative computed tomographic (CT) brain scans of cSDH patients with burr-hole drainage were analysed. Pneumocephalus volume was measured independently by both the ABC/2 formula and the computer-assisted volumetric measurement. For the computer-assisted measurement, the volume of the air was semiautomatically segmented and calculated by computer software. Linear regression was used to determine the correlation between the ABC/2 method and computer-assisted measurement. RESULTS: The postoperative pneumocephalus volume after bilateral burr-hole drainage was significantly larger than that of unilateral burr-hole drainage (29.34 ml versus 12.21 ml, p < 0.001). The estimated volumes by the formula ABC/2 significantly correlated to the volumes as measured by the computer-assisted volumetric technique, with r = 0.992 (p < 0.001). The Pearson correlation coefficient is very close to 1, which signifies a very strong positive correlation, and it is statistically significant. CONCLUSIONS: An excellent correlation is observed between the ABC/2 method and the computer-assisted measurement. This study verified that the ABC/2 method is an accurate and simple "bedside" technique to estimate pneumocephalus volume.

Predictive value of Bispectral Index (BIS) in emergency neurosurgical patients: Loss of BIS reactivity to propofol predicts poor functional outcomes.

AIM: In emergency neurosurgical patients, evaluation with Glasgow Coma Scale (GCS) alone immediately after stopping sedation post-operatively might not differentiate those with good recovery from those with poor outcomes at 3 months. This study aimed to evaluate the prognostic value of measuring the Bispectral Index (BIS) and the correlation to propofol dosage during the use of sedation in the early post-operative period. METHODS: This is a prospective study on consecutive post-operative neurosurgical patients admitted to the neurosurgical ICU on propofol sedation. The primary outcome was the correlation between early post-operative BIS and the Propofol dosage with the modified Rankin scale (mRS) at 3 months. Secondary outcomes included the post-operative propofol requirement in patients with good functional outcomes (mRS 0-3) versus poor functional outcomes (mRS 4-6) at 3 months. RESULTS: In total, 728 BIS readings were collected from twenty-four patients for analysis. The BIS readings were significantly correlated to the propofol dosage in patients with good function outcomes at 3 months (p < 0.0001). BIS readings in patients with no associations to changes in propofol dosage during their ICU stay had poor outcomes (mRS 4-6) at 3 months (r = -0.0407). For patients with good functional outcomes at 3 months, a significantly higher propofol dosage was used for deep sedation (BIS 40 - 60) during the post-operative period (p < 0.001). CONCLUSION: For emergency neurosurgical patients whose BIS readings had lost correlation to the propofol dosage upon recovery, their functional outcomes at 3 months were poor. For those with good functional outcomes at 3 months, a significantly higher propofol dosage was required for deep sedation during their ICU stay. Patients with preserved correlation of BIS readings to changes in propofol dosages during the early post-operative period were associated with good functional outcomes at 3 months.

Univariate and Multivariable Analyses on Independent Predictors for Cervical Spinal Injury in Patients with Head Injury.

OBJECTIVE: This study aims to identify independent factors associated with cervical spinal injuries in head-injured patients. The extent of injuries to other body parts was assessed by the Abbreviated Injury Scale (AIS) and was included in the analysis. METHODS: Consecutive head-injured patients admitted via the emergency department from January 1, 2014 to December 31, 2016 were retrospectively reviewed. The inclusion criteria were head-injured patients with an Abbreviated Injury Scale (AIS) score ≥2 (i.e., head injuries with intracranial hematoma or skull fracture). Patients with minor head injuries with only scalp abrasions or superficial lacerations without significant intracranial injuries (i.e., head injury AIS score = 1) were excluded. The primary outcome was to identify independent predictors associated with cervical spinal injuries in these head-injured patients. Univariate and multivariable analyses were conducted. RESULTS: A total of 1105 patients were identified. Of these patients, 11.2% (n = 124) had cervical spinal injuries. Univariate and multivariable analyses identified male gender (P = 0.006), the presence of thoracic injury (including rib fracture, hemothorax, or pneumothorax) (P = 0.010), and hypotension with systolic blood pressure <90 mm Hg on admission (P = 0.009) as independent predictors for cervical spinal injury in head-injured patients. CONCLUSIONS: This study showed that about 1 in 10 patients with significant head injury had cervical spine injury, usually associated with fracture or dislocation. Male gender, the presence of thoracic injury, and hypotension on admission were independent risk factors associated with cervical spinal injuries.

Deep brain stimulation in a young child with GNAO1 mutation - Feasible and helpful.

Background: GNAO1 is an emerging disorder characterized with hypotonia, developmental delay, epilepsy, and movement disorder, which can be potentially life threatening during acute exacerbation. In the USA, deep brain stimulation (DBS) has been licensed for treating children with chronic, treatment-resistant primary dystonia, who are 7 years old or older. Case Description: A 4-year-old girl diagnosed to have GNAO1-related dyskinesia and severe global developmental delay. She had severe dyskinesia precipitated by intercurrent infection, requiring prolonged intensive care for heavy sedation and related complications. Her dyskinesia improved dramatically after DBS implantation. Technical difficulties and precautions of DBS in preschool children were discussed. Conclusion: DBS should be considered early in the treatment of drug-resistant movement disorders in young children with GNAO1, especially after dyskinetic crisis, as they tend to recur. Presurgical counseling to parents and close monitoring of complications is also important in the process.

Urokinase Is Safe and Effective in Reducing Recurrence in Chronic Subdural Hematoma After Burr-Hole Drainage.

OBJECTIVE: This study aimed to evaluate the safety and efficacy of subdural urokinase in reducing the recurrence of chronic subdural hematoma (cSDH). METHODS: Consecutive adults with cSDH and burr-hole drainage from 1 January 2013 to 31 December 2017 were retrospectively analyzed. Clinical records, radiologic images, laboratory data, and medication records were reviewed. The primary outcome was the recurrence rate of cSDH in patients with or without urokinase instillation. Secondary outcomes included complication rates such as infection and acute intracranial hemorrhage. Univariate and multivariate analyses were conducted to identify independent factors associated with cSDH recurrence. RESULTS: A total of 297 consecutive patients were identified for analysis. The average dosage of urokinase instillation via the subdural drain into the subdural space was 15,800 units (5000-60,000 units) over a mean duration of 2 days (1-6 days). The symptomatic recurrence rate of cSDH was significantly lower with urokinase at 3.0% versus 11.7% with no urokinase (odds ratio: 0.234; P = 0.022). Univariate analysis and multivariate analysis showed that bilateral cSDH and the presence of underlying liver disease were significantly associated with higher recurrence, while the instillation of urokinase was significantly and independently associated with lower recurrence (odds ratio = 0.311; P = 0.005). Complication rates including infection and hemorrhage were comparable with patients with or without urokinase and had no significant difference. CONCLUSIONS: Instillation of urokinase was safe for patients with cSDH. The recurrence rate of cSDH was significantly lower with urokinase.

Return to work after injury in Hong Kong: prospective multi-center cohort study.

PURPOSE: Trauma remains a major cause of morbidity and disability worldwide; however, reliable data on the health status of an urban Asian population after injury are scarce. The aim was to evaluate 1-year post-trauma return to work (RTW) status in Hong Kong. METHODS: This was a prospective, multi-center cohort study involving four regional trauma centers from 2017 to 2019 in Hong Kong. Participants included adult patients entered into the trauma registry who were working or seeking employment at the time of injury. The primary outcome was the RTW status up to 1 year. The Extended Glasgow Outcome Scale, 12-item Short Form (SF-12) survey and EQ5D were also obtained during 1-, 3-, 6-, 9-, and 12-month follow-ups. Multivariable Cox proportional hazards regression analysis was used for analysis. RESULTS: Six hundred and seven of the 1115 (54%) recruited patients had RTW during the first year after injury. Lower physical requirements (p = 0.003, HR 1.51) in pre-injury job nature, higher educational levels (p < 0.001, HR 1.95), non-work-related injuries (p < 0.001, HR 1.85), shorter hospital length of stay (p = 0.007, HR 0.98), no requirement for surgery (p = 0.006, HR 1.34), and patients who could be discharged home (p = 0.006, HR 1.43) were associated with RTW within 12 months post-injury. In addition, 1-month outcomes including extended Glasgow Outcome Scale ≥ 6 (p = 0.001, HR 7.34), higher mean SF-12 physical component summary (p = 0.002, HR 1.02) and mental component summary (p < 0.001, HR 1.03), and higher EQ5D health index (p = 0.018, HR 2.14) were strongly associated with RTW. CONCLUSIONS: We have identified factors associated with failure to RTW during the first year following in Hong Kong including socioeconomic factors, injury factors and treatment-related factors and 1-month outcomes. Future studies should focus on the interventions that can impact on RTW outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT03219424.

Chronic subdural haematoma during the COVID-19 lockdown period: late presentation with a longer interval from the initial head injury to the final presentation and diagnosis.

BACKGROUND: The COVID-19 novel coronavirus is contagious, and the mortality is higher in the elderly population. Lockdown in different parts of the world has been imposed since January 2020. Chronic subdural haematoma (cSDH) has a unique natural history in which symptoms can be non-specific, and the onset is insidious. This study aims to evaluate the impact of the COVID-19 pandemic on the presentation of cSDH. METHODS: Consecutive adult cSDH patients admitted from 1 March 2020 to 30 April 2020 were reviewed. Exclusion criteria including those who had no definite history of head injury or the diagnosis of cSDH were made from a scheduled follow-up scan. Corresponding data during the same period in 2019 were reviewed for comparison. The primary outcome was the interval between the initial head injury and the final radiological diagnosis of cSDH. Secondary outcomes include Markwalder chronic subdural haematoma grade upon admission, length of stay in the acute hospital, and the modified Rankin scale (mRS) upon discharge. RESULTS: For the primary outcome, the average interval between head injury and the diagnosis of cSDH was significantly longer at 56.6 days (49 to 74 days, SD 9.83 days) during the period from March to April 2020, versus 29.4 days (17 to 42 days, SD 8.59 days) in 2019 for the corresponding period (p = 0.00703). There was no significant difference in the functional outcome upon discharge. CONCLUSIONS: cSDH patients can present late during the COVID-19 lockdown period. The functional outcome was comparable when operations for drainage were timely performed.

Successful Emergency Rescue Open Embolectomy for Failed Endovascular Thrombectomy in Acute Ischemic Stroke: 2-Dimensional Operative Video.

This operative video demonstrates an open surgical thrombectomy for a 61-yr-old woman with failed endovascular embolectomy in acute ischemic stroke. Good functional outcome can be achieved when this operation is timely performed within the therapeutic window. This patient has atrial fibrillation. She was admitted for sudden onset of left-sided hemiplegia and aphasia. National Institutes of Health Stroke Scale (NIHSS) was 20/42 before the operation. Computed tomography (CT) cerebral angiogram showed right internal cerebral artery (ICA) occlusion from the cervical portion. Urgent intra-arterial (IA) thrombectomy was started 2 h after symptom onset, but failed despite the use of a stentriver and a large-bore aspiration catheter together. Emergency rescue open thrombectomy was performed with right pterional craniotomy 6 h after symptom onset. Sylvian fissure was dissected to expose the supraclinoid ICA, ICA bifurcation, A1, and M1. A transverse arteriotomy was made at the ICA bifurcation and open surgical thrombectomy was performed. Reperfusion was established in 86 min after skin incision. Intraoperative indocyanine green video-angiography showed patent flow over ICA bifurcation to M1 and A1. She had a good recovery with the return of the left-sided power and was discharged home. At 2-mo postoperative assessment, she was able to walk unaided independently. The modified Barthel Index (BI) was 74/100. Her activity of daily living was independent. We must emphasize IA thrombectomy is the standard treatment, and the role of open surgery remains a potential rescue procedure. Good functional outcome can be achieved when emergency rescue open thrombectomy is performed within the therapeutic window.

Improving Survival with Tranexamic Acid in Cerebral Contusions or Traumatic Subarachnoid Hemorrhage: Univariate and Multivariate Analysis of Independent Factors Associated with Lower Mortality.

BACKGROUND: Fall with head injury is a pervasive challenge, especially in the aging population. Contributing factors for mortality include the development of cerebral contusions and delayed traumatic intracerebral hematoma. Currently, there is no established specific treatment for these conditions. OBJECT: This study aimed to investigate the impact of independent factors on the mortality rate of traumatic brain injury with contusions or traumatic subarachnoid hemorrhage. METHODS: Data were collected from consecutive patients admitted for cerebral contusions or traumatic subarachnoid hemorrhage at an academic trauma center from 2010 to 2016. The primary outcome was the 30-day mortality rate. Independent factors for analysis included patient factors and treatment modalities. Univariate and multivariate analyses were conducted to identify independent factors related to mortality. Secondary outcomes included thromboembolic complication rates associated with the use of tranexamic acid. RESULTS: In total, 651 consecutive patients were identified. For the patient factors, low Glasgow Coma Scale on admission, history of renal impairment, and use of warfarin were identified as independent factors associated with higher mortality from univariate and multivariate analyses. For the treatment modalities, univariate analysis identified tranexamic acid as an independent factor associated with lower mortality (P = 0.021). Thromboembolic events were comparable in patients with or without tranexamic acid. CONCLUSION: Tranexamic acid was identified by univariate analysis as an independent factor associated with lower mortality in cerebral contusions or traumatic subarachnoid hemorrhage. Further prospective studies are needed to validate this finding.

Blessing or burden? Long-term maintenance, complications and clinical outcome of intrathecal baclofen pumps.

AIM: The intrathecal baclofen pump is an effective treatment for spasticity. However, long-term results have reported patients' dissatisfaction and perception of disability. Potential causes include a frequent need for baclofen pump refill and risks of complications. The aim of the present study was to evaluate the long-term maintenance, complications and clinical outcome of intrathecal baclofen pumps. PATIENTS AND METHODS: We conducted a 16-year retrospective cohort study of patients with spasticity treated with an intrathecal baclofen pump at a university hospital from 2000 to 2016. The primary outcome was the rate of infection per puncture for baclofen pump refill. Secondary outcomes included the incidence of other complications, such as running out of baclofen causing symptomatic withdrawal symptoms, pump mechanical failure, pump battery end of life and the need for pump replacement. The clinical outcome was assessed by the Modified Ashworth Scale (mAS). RESULTS: In total, 340 follow-up episodes with pump refill procedures were recorded. The average interval between each pump refill was 57.3 days (±15.4 days). The average duration of admission for each pump refill was 4 h and 49 min (from 2 h 23 min to 10 h). There were two events with established infection after puncture for the refill, giving rise to an infection rate per puncture of 0.6 percent (2/340).For the long-term clinical outcome, at an average follow-up period of 7.6 years, the postoperative mAS for spasticity was 2.0 ± 0.756, which was significantly better than the preoperative mAS at 3.75 ± 0.462 (P = 0.001). CONCLUSION: Long-term aftercare with baclofen pump refill was safe, with an infection rate of 0.6 per cent per puncture for each refill. Long-term intrathecal baclofen pump was effective in the treatment of spasticity with persistent significant improvement in the spasticity scale.

Awake craniotomy for excision of arteriovenous malformations? A qualitative comparison study with stereotactic radiosurgery.

Treatment of arteriovenous malformations (AVM) located at the eloquent area has been a challenge. Awake brain mapping allows identification of a non-eloquent gyrus for intervention and can potentially facilitate resection with preservation of functions. An alternative treatment option is stereotactic radiosurgery (SRS). The objective of this study was to perform a qualitative comparison of the treatment outcome of awake AVM excision versus SRS. We conducted a 13-year retrospective review of AVM excision under awake craniotomy performed at Prince of Wales Hospital, Hong Kong, from 2003 to 2016. Patients' presentation, Spetzler-Martin (SM) grading, rate of obliteration and complication were reviewed and analyzed with the modified radiosurgery-based AVM score (RS score). Six patients had excision of AVM under awake mapping during this period of time. Two were SM Grade II and four were SM Grade III. Five located at the peri-rolandic region while one at the temporal language area. None had failed mapping. Five out of six achieved complete obliteration (83.3%). Qualitative comparative analysis had revealed better treatment outcome with awake AVM excision as compared to SRS with the obliteration rate of 100% versus 96% for RS score ≤1.00, 100% versus 78% for RS score 1.01-1.50, and 66% versus 50% for RS score >2.00 respectively. In conclusion, awake mapping and excision of AVMs at the eloquent area is feasible. Qualitative comparative analysis had revealed higher obliteration rate with awake AVM excision as compared to SRS.

Primary cranial vault lymphoma.

A 49-year-old woman presented to our institution with a progressive frontal scalp swelling for one year. Incisional biopsy was performed and histological examination showed diffuse large B-cell lymphoma. The case details and management were discussed.

Cryostored autologous skull bone for cranioplasty? A study on cranial bone flaps' viability and microbial contamination after deep-frozen storage at -80°C.

Craniectomy is a life-saving procedure. Subsequent cranioplasty with autologous skull bone has a bone resorption rate from 4% to 22.8% and an infection rate from 3.3% to 26%. There are concerns with their viability and the potential microbial contamination as they were explanted for a long period of time. Eighteen cranial bone flaps stored at Prince of Wales Hospital Skull Bone Bank during the period from June 2011 to March 2016 were identified. Ethics approval was obtained. Bone chips and deep bone swabs were collected for osteoblast culture and microbial culture. Skull Bone Bank was kept at -80°C under strict aseptic technique during the study period. The storage period ranged from 4months to 55months. For the osteoblast culture, all eighteen bone flaps had no viable osteoblast growth. For the bacterial culture, five had positive bacteria growth (27.8%). Three were Pasteurella multocida and two were Methicillin-resistant Staphylococcus aureus. The mean duration of storage of the infected bone flap was 32.9months (±15.1months) versus 19.9months (±17.9months) of those bone flaps with no bacterial growth (p=0.1716). The mean size of the infected versus non-infected bone flaps was 117.7cm2 (±44.96cm2) versus 76.8cm2 (±50.24cm2) respectively (p=0.1318). Although in this study statistical significance was not reached, it was postulated that infected bone flaps tended to be larger in size and had a longer duration of storage. In conclusion, cryostored skull bone flaps beyond four months showed no viable osteoblasts. Bacterial contamination rate of bone flaps was 27.8% in this study.

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.

The use of atorvastatin for chronic subdural haematoma: a retrospective cohort comparison study.

Chronic subdural haematoma (CSDH) is a common neurosurgical condition. Burr-hole for drainage is an effective treatment. However, recurrence can be up to 8-33% and is associated with morbidities and mortalities. The underlying pathogenesis was postulated to be localised inflammation and pathological aberrant vessels formation. Atorvastatin, an HMG-CoA reductase inhibitor, is a type of lipid-lowering medication. In animal studies and a preliminary clinical trial, Atorvastatin was shown to be effective in the treatment of CSDH. It was found to inhibit inflammation and promote vascular maturation at the neomembrane of CSDH. Our study aimed to investigate the efficacy of Atorvastatin in CSDH. During the study period from January to December 2014, Atorvastatin was used in 12 CSDH patients with Glasgow Coma Scale (GCS) 13-15 or Markwalder's Grading Scale (MGS) Grade 0-2. They were retrospectively compared with GCS- and MGS-matched controls who had not used statin. Improvement with haematoma resolution at 3 months was 75% (9/12) for the Atorvastatin group, versus 42% (5/12) for the Control group (p = 0.0977). The risk of deterioration requiring burr-hole drainage was 16.7% (2/12) in the Atorvastatin group, versus 58.3% (7/12) in the Control group (p = 0.0447). The Odds Ratio (OR) of deterioration requiring burr-hole drainage with Atorvastatin was 0.143 (95%CI: 0.021-0.958), which favours the use of Atorvastatin in CSDH (p = 0.0451). The Number needed to treat (NNT) was 2.4 (p = 0.0447; 95%CI: 1.31-14.93). In conclusion, this retrospective cohort comparison study has shown that CSDH with Atorvastatin had a lower rate of deterioration and burr-hole drainage.