Unilateral microscopic approach for lumbar spinal stenosis decompression: a scoping review.

BACKGROUND: Microscopic unilateral laminotomy for bilateral decompression (ULBD) is a minimally invasive technique used in the treatment of lumbar spinal stenosis and could limit spinal instability and be associated with better clinical outcomes. However, there is ongoing debate regarding its utility compared to conventional laminectomy (CL). The primary objective was to collate and describe the current evidence base for ULBD, including perioperative parameters, functional outcomes, and complications. The secondary objective was to identify operative techniques. METHODS: A scoping review was conducted between January 1990 and August 2022 according to the PRISMA extension for scoping reviews (PRISMA-ScR) guidelines. Major databases were searched for full text English articles reporting on outcomes following microscopic unilateral laminotomy in patients with lumbar spinal stenosis. RESULTS: Seventeen articles met the inclusion criteria. Two studies were randomised controlled trials. Two studies were prospective data collection and the rest were retrospective analysis. Three studies compared ULBD with CL. ULBD preserves the osteoligamentous complex and may be associated with shorter operative time, less blood loss, and similar clinical outcomes when compared to CL. CONCLUSION: This review highlights that ULBD aims to minimise disruption to the normal posterior spinal anatomy and may have acceptable clinical outcomes. It also highlights that it is difficult to draw valid conclusions given there are limited data available as most studies identified were retrospective or did not have a comparator group.

CSF rhinorrhoea after endonasal intervention to the anterior skull base (CRANIAL): proposal for a prospective multicentre observational cohort study.

BACKGROUND: The endonasal transsphenoidal approach (TSA) has emerged as the preferred approach in order to treat pituitary adenoma and related sellar pathologies. The recently adopted expanded endonasal approach (EEA) has improved access to the ventral skull base whilst retaining the principles of minimally invasive surgery. Despite the advantages these approaches offer, cerebrospinal fluid (CSF) rhinorrhoea remains a common complication. There is currently a lack of comparative evidence to guide the best choice of skull base reconstruction, resulting in considerable heterogeneity of current practice. This study aims to determine: (1) the scope of the methods of skull base repair; and (2) the corresponding rates of postoperative CSF rhinorrhoea in contemporary neurosurgical practice in the UK and Ireland. METHODS: We will adopt a multicentre, prospective, observational cohort design. All neurosurgical units in the UK and Ireland performing the relevant surgeries (TSA and EEA) will be eligible to participate. Eligible cases will be prospectively recruited over 6 months with 6 months of postoperative follow-up. Data points collected will include: demographics, tumour characteristics, operative data), and postoperative outcomes. Primary outcomes include skull base repair technique and CSF rhinorrhoea (biochemically confirmed and/or requiring intervention) rates. Pooled data will be analysed using descriptive statistics. All skull base repair methods used and CSF leak rates for TSA and EEA will be compared against rates listed in the literature. ETHICS AND DISSEMINATION: Formal institutional ethical board review was not required owing to the nature of the study - this was confirmed with the Health Research Authority, UK. CONCLUSIONS: The need for this multicentre, prospective, observational study is highlighted by the relative paucity of literature and the resultant lack of consensus on the topic. It is hoped that the results will give insight into contemporary practice in the UK and Ireland and will inform future studies.

Drainage of an extradural haematoma by intraosseous needle in a remote hospital.

We report the case of an intraosseous needle used to drain an acute extra-dural haematoma in a remote hospital. An 18 yr. old female attended the Emergency Department, after sustaining a closed head injury from a fall. After a CT scan, she was diagnosed with a large acute extradural haematoma (EDH). Prior to air ambulance transfer to the Neurosurgical Centre, she developed a fixed dilated pupil and hemodynamic instability. The Neurosurgeon advised that an intraosseous (IO) needle drainage would prevent brain stem herniation. An Emergency Medicine (EM) consultant drained 60 ml of blood and clot via an IO needle. The pupil and cardiovascular status normalised. The patient underwent neurosurgical drainage with full neurological recovery. We believe that this is the first IO drainage of an EDH at a remote hospital followed by full neurological recovery.

Surgical Treatment of Chronic Subdural Hematomas in Nonagenarians: Who to Treat?

OBJECTIVE: Although chronic subdural hematomas (cSDH) are often treated surgically it remains plausible that invasive treatment in elderly patients may have a negative effect on survival. The aim of this study was to characterize survival following neurosurgical intervention for cSDH in a selected cohort aged >90 years and to identify prognostic factors that may inform clinical decision-making. METHODS: In total, we identified a cohort of 548 consecutive patients who had undergone burr hole drainage for cSDH in a 5-year period between 2009-2013. Of these patients, 41 were aged >90 years. For each patient, information was gathered from local hospital records, general practice records, and the patients directly. Long-term survival was compared with actuarial data obtained from the National Life Tables. RESULTS: Overall mortality at the time of discharge was 2%. Mortality was 26.8% at 6 months, 36.8% at 1 year, and 47.9% at 2 years. Interestingly, there was no significant difference between the actuarial curve and the survival curve following surgery (hazard ratio, 1.17; confidence interval, 0.67-2.05; P = 0.57). Despite initially departing from the actuarial curve, the survival curve becomes parallel at approximately 1 year. Multivariate analysis showed that preadmission residence and the number of comorbid conditions were significant predictors of survival. CONCLUSIONS: We advocate that neurosurgical intervention for cSDH in selected nonagenarians can be a safe and beneficial procedure. Patients living independently at home and with a limited past medical history were most likely to benefit from the surgery.

Emergency Intraoperative Ultrasound for the Neurosurgical Trainee.

The use of intraoperative ultrasound in emergency cranial neurosurgical procedures is not well described. It may improve surgical outcomes and is useful when other neuro-navigation systems are not readily available. We provide a practical guide for neurosurgical trainees to utilize ultrasound for various emergency cranial neurosurgical procedures, including lesion localization, insertion of an external ventricular drain, and shunt revision surgery. Intraoperative ultrasound is a useful modality for urgent neurosurgical procedures.

Idiopathic Intracranial Hypertension: Shunt Failure and the Role of Obesity.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a chronic condition characterized by raised intracranial pressure in the absence of a known etiology. IIH typically presents in overweight women of childbearing age. Surgical intervention for IIH involves diversion of cerebrospinal fluid, often by the placement of a shunt. Experience suggests higher shunt failure rates in patients with IIH than shunts placed for other etiologies. Here we sought to both establish and compare failure rates for IIH and non-IIH shunts and to examine association with body mass index (BMI). METHODS: This study was a single-center retrospective consecutive cohort over a 13-year period. There were 1264 non-IIH patients and 116 patients with IIH included in the study. This was a retrospective analysis of time to shunt failure using Kaplan-Meier methods for IIH and non-IIH shunts. Secondary analysis of BMI, shunt type, and sex on IIH shunt failure was also conducted. RESULTS: The median time to failure of the initial IIH shunt was 22.9 months (interquartile range [IQR], 4-55) compared with 57 months (IQR, 12-87) in non-IIH shunts (P < 0.001; 95% confidence interval, 58.6-233.6). In the IIH group, the median shunt survival for BMI above the healthy range (18.5-25 kg/m2) was 18 months relative to 44 months for those with a healthy BMI. CONCLUSIONS: Our study suggests that in IIH, relative to hydrocephalus of other causes, shunts have higher failure rates and often require more frequent revisions. Higher shunt failure rates in patients with IIH may be associated with an unhealthy BMI.

Image guidance and improved accuracy of external ventricular drain tip position particularly in patients with small ventricles.

OBJECTIVE: External ventricular drain (EVD) insertion is one of the most common emergency neurosurgical procedures. EVDs are traditionally inserted freehand (FH) in an emergency setting, but often result in suboptimal positioning. Image-guided surgery (IGS) is selectively used to assist placement. However, the accuracy and practicality of IGS use is yet to be reported. In this study, the authors set out to assess if IGS is practical and improves the accuracy of EVD placement. METHODS: Case notes and images obtained in patients who underwent frontal EVD placement were retrospectively reviewed. Ventriculomegaly was determined by the measurement of the Evans index. EVD location was classified as optimal (ipsilateral frontal horn) or suboptimal (any other location). Propensity score matching of the two groups (IGS vs FH) for the Evans index was performed. Data were analyzed for patient age, diagnosis, number of EVDs, and complications. Those without postoperative CT scans were excluded. RESULTS: A total of 607 patients with 760 EVDs placed were identified; 331 met inclusion criteria. Of these, 287 were inserted FH, and 44 were placed with IGS; 60.6% of all unmatched FH EVDs were optimal compared with 75% of the IGS group (p = 0.067). The IGS group had a significantly smaller Evans index (p < 0.0001). Propensity score matching demonstrated improved optimal position in the IGS group when compared with the matched FH group (75% vs 43.2%, OR 4.6 [1.5-14.6]; p = 0.002). Patients with an Evans index of ≥ 0.36 derived less benefit (75% in IGS vs 66% in FH, p = 0.5), and those with an Evans index < 0.36 derived more benefit (75% in IGS vs 53% in FH, p = 0.024). The overall EVD complication rate was 36% in the FH group versus 18% in the IGS group (p = 0.056). Revision rates were higher in the FH group (p = 0.035), and the operative times were similar (p = 0.69). Long intracranial EVD catheters were associated with tip malposition irrespective of the group. CONCLUSIONS: Image guidance is practical and improves the accuracy of EVD placement in patients with small ventricles; thus, it should be considered for these patients.

An Evaluation of Commonly Used External Ventricular Drain Securement Methods in a Porcine Model: Recommendations to Improve Practice.

BACKGROUND: External ventricular drain (EVD) dislodgement is common and leads to significant morbidity and mortality. Many securement techniques to prevent this are described. There are, however, no objective studies comparing them. This study aimed to determine the most secure method of securing an EVD. METHODS: A survey was distributed through the British Neurosurgical Trainee Research Collaborative to determine common EVD securement methods and select techniques for testing. Securement methods were tested in a pig cadaver model. Peak pull force before EVD failure was measured. Failure was defined as catheter displacement 1 cm from the insertion site, catheter fracture, or suture fracture. RESULTS: Twenty-three neurosurgical units responded. Five basic EVD securement methods were in common use. These were tested in isolation and in combination so that in total 15 common methods were tested. The most secure method was a triple construct, consisting of an anchoring suture, sutures around a coil of the catheter, and either a soft plastic flange (25.85 N, 95% confidence interval 24.95 N-26.75 N) or a hard plastic flange (29.05 N, 95% confidence interval 25.69 N-32.41 N). Of the individual methods, single anchoring sutures, soft flanges, VentriFix, and staples were found to be the least secure, whereas multiple sutures and hard flanges were the most secure. CONCLUSIONS: An anchoring suture followed by a coil of the catheter and finally a flange is the most secure method for securing EVDs. This simple technique can withstand up to 8.2 times the force of a single anchoring suture, is easily used, and decreases the likelihood of EVD dislodgement and associated complications.

Temporising extradural haematoma by craniostomy using an intraosseous needle.

We report a novel application of intraosseous needle drainage, alleviating raised intracranial pressure due to extradural haematoma. The potential application of this technique in preventing secondary brain injury and herniation during transfer to a neurosurgical unit is discussed.

Degree and Duration of Functional Improvement on Long-Term Follow-Up of Spinal Dural Arteriovenous Fistulae Occluded by Endovascular and Surgical Treatment.

BACKGROUND: Long-term outcomes following occlusion of spinal dural arteriovenous fistula (SDAVF) are poorly understood and are based on small series reporting predominantly short-term outcomes. The degree and duration of improvement remain unclear. In this study, we analyzed long-term outcomes following occlusion in a cohort of patients with SDAVF. METHODS: This was a single-center cohort study of patients with SDAVF identified from a prospective database. Outcomes were assessed using a modified Aminoff and Logue Disability (ALD) Scale, the modified Rankin Scale (mRS), and patient-reported outcomes at presentation and long-term follow-up. Both angiographic recanalization and idiopathic functional recurrence rates were calculated. RESULTS: Of the total of 67 patients with SAVDF identified, 59 were eligible for inclusion in this study. Fifty-seven of these 59 (97%) underwent occlusion. Twenty-two patients underwent initial embolization; 12 were occluded. Two patients recanalized. Eleven patients underwent surgery after attempted embolization; 10 were occluded. Thirty-seven patients treated by surgery only were occluded. The median duration of follow-up was 63 months (range, 12-240 months). After occlusion, the ALD gait and urinary scores improved by a median of 1 point. Although the median mRS score was unchanged, 49% of the patients experienced improvement, most by 1 point. There was no difference between the patients occluded by embolization or surgery, but those requiring both approaches had worse gait and urinary scores (P = 0.005 and 0.03, respectively). The duration of symptoms by itself had no effect on outcomes (P = 0.61). Following occlusion, 5 patients experienced an idiopathic late functional deterioration. Of 16 patients presenting with paraplegia, 13 (81%) improved, with a median mRS improvement of 1 point. CONCLUSIONS: Following occlusion, patients with SDAVF experienced a modest improvement in symptoms, most commonly by 1 point on the ALD scale. Idiopathic late deterioration was seen in 9.1% of patients.

Anterior cervical discectomy plus intervertebral polyetheretherketone cage fusion over three and four levels without plating is safe and effective long-term.

Anterior cervical discectomy and fusion (ACDF) is an established treatment for single-level cervical spondylotic myelopathy and radiculopathy, yet its stand-alone use for multi-level disease of the subaxial cervical spine remains controversial. We report a prospectively studied case series of 30 patients receiving polyetheretherketone (PEEK) cage fusion over three and four cervical levels without anterior plating. Seven (23.3%) four-level procedures (all C3 to C7) were performed, the other 23 (76.7%) being three-level, with 19 (64.4%) at C4 to C7 and four (12.3%) at C3 to C6. Long-term follow-up of more than 2 years was available in 67% of patients. This cohort showed statistically significant improvements in visual analogue score for neck pain (p=0.0006), arm pain (p=0.0003) and Japanese Orthopaedic Association myelopathy score (p=0.002). Fused segment heights increased by 0.6-1.1%. Adjacent segment disease requiring ACDF at C3-4 was seen in 6.7% of patients (one after trauma) at a mean follow-up of 62 months. Same segment recurrence requiring posterior decompression with instrumented fusion was found in 10% of patients at a mean follow-up of 49 months, only one of whom had radiological evidence of cage subsidence. The results suggest the procedure is safe and effective with potentially less morbidity than anterior plating, shorter inpatient stays than posterior approaches, acceptable same segment recurrence and lower than predicted adjacent segment disease rates.