Are we meeting the standards set for informed consent in spinal surgery?

INTRODUCTION

Informed consent empowers patients to exercise their autonomy and actively participate in their medical care. Guidance published by the British Association of Spine Surgeons (BASS) lists three components of consent: provision of information booklets, patient-centred dialogue and completion of appropriate consent forms. The aim of the study was to review the quality of the spinal surgery consent process against the BASS guidance in a single tertiary neurosurgery centre in London.

METHODS

Retrospective review of clinic letters and consent forms was performed for 100 consecutive cases of elective, non-instrumented spinal decompression surgeries performed in 2019. Documentation was graded for inclusion of the intended benefit (improvement of pain/prevention of neurological deterioration), alternative management options (including no treatment), surgical options and risks (infection, bleeding, paralysis, sphincter disturbances, dural tear and recurrence). Provision of supplementary information booklets was recorded. Two-tailed Fisher exact test was used to calculate statistical significance where appropriate.

RESULTS

Documentation of indications and risks of elective spinal surgery, specifically risk of recurrence (62%) and sphincter disturbance (85%), was suboptimal on the consent forms. Documentation of these risks was also poor in clinic letters (<50%). Alternative treatment options were explained in less than half of the clinic letters, and there was no documentation of information booklet provision prior to elective surgeries.

CONCLUSION

Lack of informed consent plays a major role in medical malpractice claims in spinal surgery. Poor documentation puts the surgeon in a liable position. BASS guidance could be implemented to create a more standardised process of consent in spinal surgery.

Intrathecal baclofen overdose mimicking brainstem death during deep brain stimulation surgery for pain

We describe a unique case of intrathecal baclofen overdose mimicking brainstem death, during bilateral anterior cingulate cortex deep brain stimulation (DBS) for pain. A 37-year-old man with chronic regional pain syndrome requiring an intrathecal baclofen pump underwent DBS under general anaesthesia and experienced an intraoperative generalised tonic-clonic seizure on dural opening. Once the operation was completed, the patient was noted to have fixed, dilated pupils bilaterally and was transferred for an emergency computed tomography scan of the head, which did not reveal any acute intracranial pathology. The patient was transferred to the intensive care unit for management of concurrent hypotension, bradycardia and supportive management of his low Glasgow Coma Scale (GCS) score. A trial of atropine to counter the bradycardia was unsuccessful. Intrathecal baclofen toxicity was suspected as a diagnosis of exclusion, necessitating urgent aspiration of the baclofen pump. The patient's GCS score improved after pump aspiration and he was discharged home several days later. It was noted that the intrathecal baclofen pump had been refilled several days previously and the patient had reported intermittent episodes of somnolence. In perioperative patients with intrathecal baclofen pumps in situ, baclofen toxicity should always be considered as a differential in perioperative complications, even if it is considered a rare event.

307 Improving Compliance with Standard of Care Guidelines for Suspected Cauda Equina Syndrome Across A District General Hospital Network

Introduction

Cauda equina syndrome (CES) is a spinal emergency that cannot be reliably detected through clinical examination alone and as a result requires prompt MR imaging to provide a diagnosis. This audit examined compliance to standard of care following service improvements in line with the updated SBNS/BASS national guidelines for CES.

Method

A retrospective analysis of 200 patients referred to neurosurgery for suspected CES: 100 pre- and 100 post-service improvement SBNS guideline implementation.

The online neurosurgical database was reviewed, cases assessed for completeness of referral information (including appropriate exam and pre-referral MRI) with patient demographics, referring hospital and outcome also recorded.

Results

Prior to the SBNS guidelines only 19 patients received MRI prior to referral, 70% of all referrals were incomplete or contained erroneous clinical information. Post-service improvements there was a 68% increase of pre-referral MRI (32 cases), and an improvement in quality of clinical information with only 19% of referrals providing insufficient or unreliable information.

Conclusions

Through relatively simple changes to local policy, patient care flow and education of emergency department clinicians we have significantly improved pre-referral MRI rates as well as overall referral quality across the whole DGH network.

Fulminant intracranial hypertension secondary to oxytetracycline requiring urgent ventriculo-peritoneal shunt insertion

Idiopathic intracranial hypertension is a syndrome that presents with headaches and visual loss. Its pathogenesis is unknown. Treatment options include acetazolamide, therapeutic lumbar punctures or permanent CSF diversion. We present the only reported case of acute drug-induced intracranial hypertension secondary to oxytetracycline requiring urgent cerebrospinal fluid diversion. The patient's rapid visual failure progressed daily despite discontinuation of the drug and required an urgent ventriculo-peritoneal (VP) shunt insertion. Patients should be counselled about the rare potential risk of developing intracranial hypertension when commencing oxytetracycline. Rapid visual failure in IIH is a neurosurgical emergency necessitating urgent ventriculoperitoneal shunt insertion.

Local field potential activity dynamics in response to deep brain stimulation of the subthalamic nucleus in Parkinson's disease

Local field potentials (LFPs) may afford insight into the mechanisms of action of deep brain stimulation (DBS) and potential feedback signals for adaptive DBS. In Parkinson's disease (PD) DBS of the subthalamic nucleus (STN) suppresses spontaneous activity in the beta band and drives evoked resonant neural activity (ERNA). Here, we investigate how STN LFP activities change over time following the onset and offset of DBS. To this end we recorded LFPs from the STN in 14 PD patients during long (mean: 181.2 s) and short (14.2 s) blocks of continuous stimulation at 130 Hz. LFP activities were evaluated in the temporal and spectral domains. During long stimulation blocks, the frequency and amplitude of the ERNA decreased before reaching a steady state after ~70 s. Maximal ERNA amplitudes diminished over repeated stimulation blocks. Upon DBS cessation, the ERNA was revealed as an under-damped oscillation, and was more marked and lasted longer after short duration stimulation blocks. In contrast, activity in the beta band suppressed within 0.5 s of continuous DBS onset and drifted less over time. Spontaneous activity was also suppressed in the low gamma band, suggesting that the effects of high frequency stimulation on spontaneous oscillations may not be selective for pathological beta activity. High frequency oscillations were present in only six STN recordings before stimulation onset and their frequency was depressed by stimulation. The different dynamics of the ERNA and beta activity with stimulation imply different DBS mechanisms and may impact how these activities may be used in adaptive feedback.

Oil Film Thickness and Pressure Distribution in Elastohydrodynamic Point Contacts

In this paper, a general numerical solution to the elastohydrodynamic point contact problem is presented for moderate loads and material parameters. Isobars, contours and regression formulae describe how pressure and oil film thickness vary with geometry, material properties, load, and squeeze velocity, when the rolling velocity vector is at various angles to the static contact ellipse long axis. In addition, the EHL behaviour under spin is examined. The theoretical predictions of film thickness compare favourably with other numerical solutions to the point contact problem, as well as with experimental results which use the optical interferometry method to find film thickness and