Acute hypotension and bradycardia by medulla oblongata compression in spinal surgery

Choosing Neuroanaesthesia as a career: Marching towards new horizons

Anaesthesiology is an ever-changing science and amongst its sub-specialities, the field of neuroanaesthesia is making rapid strides. The fragility of the brain and spinal cord and the multitude of complexities involved in neurosurgery and interventional neuroradiological procedures demand dedicated training in neuroanaesthesia. With rapid advancement in other neuroscience specialties, neuroanaesthesia too has made outstanding progress, owing to establishment of structured training, publication of high-quality scientific research, and invention of novel medications and monitoring modalities. The opportunities for training in India and abroad and resources to broaden knowledge in neuroanaesthesia have increased over the last two decades. A career in neuroanaesthesia offers a great future for budding anaesthesiologists.

Central hyperventilation syndrome due to massive pneumocephalus after endoscopic third ventriculostomy: a case report

Pneumocephalus is common after brain surgeries, but usually is not substantial enough to cause serious complications. We recently encountered a case of post-operative tachypnea after an endoscopic 3rd ventriculostomy. At first, we thought that the hyperventilation was the result of residual paralysis after emergence from anesthesia, but during further evaluation we found a massive pneumocephalus. In such unusual post-operative situations, physicians should consider surgery-related complications as the possible cause as well, along with the anesthetic factors.

Adult cervicomedullary pilocytic astrocytoma: A case report

Pilocytic astrocytoma (PA) is a rare glioma, which generally occurs in children and young adults. In adult patients, the majority of PA tumors are supratentorial. Due to the low morbidity rate of the disease in adults, PA is frequently misdiagnosed and mistreated. In the present study, this rare disease was successfully treated. The study reported the case of a 48-year-old patient with a cervicomedullary occupying lesion, who complained of numbness and pain of the right limbs that persisted for >10 years, with aggravation for 1 month. A magnetic resonance imaging scan showed a sharp cervicomedullary mass extending from the lower medulla to the cervical vertebra C3 level. Intraoperatively, the medulla and upper cervical cord were found to be well-stacked. Immediately after ingression into the spinal cord along the dorsal median sulcus, the tumor mass was detected and had a gray fish-like appearance, moderate blood supply and clear boundary. After intratumoral decompression, total excision was achieved. Postoperative pathological examination confirmed that the tumor was a PA. Following discharge, the patient did not suffer from any symptoms of the lower cranial nerves and was able to walk with limited assistance.

Clinico-radiological profile and nuances in the management of cervicomedullary junction intramedullary tumors

BACKGROUND

Cervicomedullary junction (CMJ) intramedullary tumors comprise of tumors that often pose a surgical challenge even in the present era. Though classified under brainstem glioma CMJ tumors are well amenable for surgical resection and have a good outcome. Various factors are involved in the outcome of these patients following surgery and a proper pre-operative assessment is often required to reduce the morbidity and mortality.

MATERIALS AND METHODS

Patients admitted in the Department of Neurosurgery with a diagnosis of CMJ intramedullary tumors from January 2001 to January 2010 were included in the study. Patients were analyzed retrospectively regarding their symptomatology, clinical findings, radiology and outcome after surgery. All patients underwent pre-operative magnetic resonance imaging (MRI) and post-operatively all were managed in the neurosurgery intensive care unit for days to weeks or as dictated by the clinical condition of the patient.

RESULTS

A total of 32 patients were included in the present study. The number of males was 21 (65.6%) and females were 11 (34.4%) respectively. The mean age of presentation was 22.97 ± 9.8 years and the mean duration of pre-operative symptoms was 13.3 ± 12.9 months. The tumor had extension from the CMJ into the cervical region in 17 (53.1%) and into the medullary region in 14 (43.8%) patients. Tumor decompression was done in 9 (28.1%) patients and gross near total excision done in 23 (71.87%) patients.

CONCLUSIONS

Cervicomedullary tumors are a subset of tumors quite distinct from the usual brainstem tumors. Patients having predominant cervical involvement present early and have less post-operative deficits. Those with predominantly more medullary involvement present late, hence have a much more morbid outcome. Though closely related to vital neural structures, surgery forms the mainstay of treatment. Adequate pre-operative planning and preparation of the patient along with intense post-operative monitoring and ventilatory assistance as and when required helps in a good surgical outcome.

Unexpected ruptured aneurysm during posterior fossa surgery

BACKGROUND AND IMPORTANCE

Surgery is the recommended treatment for unique significant cerebellar metastasis, particularly in cases of hydrocephalus. Complications of posterior fossa surgery are associated with high risk of morbidity and mortality. We present a unique case of unexpected peroperative rupture of a cerebellar superior artery aneurysm during posterior fossa surgery.

CLINICAL PRESENTATION

During posterior cranial fossa surgery, severe arterial bleeding occurred in front of the medulla oblongata. Immediate postoperative computed tomographic (CT) angiography revealed a fusiform aneurysm from a distal branch of the left superior cerebellar artery.

CONCLUSION

To our knowledge, this is the first reported operative case of unexpected infratentorial ruptured aneurysm during posterior fossa surgery.

Spinal arteriovenous shunts presenting as intracranial subarachnoid haemorrhage

Background

In approximately 5% of patients with intracranial subarachnoid haemorrhage (SAH), the cause is another than a ruptured aneurysm or perimesencephalic haemorrhage. One of these causes is a spinal arteriovenous shunt (SAVS). The aim of this study was to investigate the characteristics of patients with SAVS who present with intracranial SAH without symptoms and signs suggesting a spinal cause.

Methods

We systematically reviewed the literature and searched the SAH database of the University Medical Center Utrecht, The Netherlands, for patients with SAVS presenting with intracranial SAH and studied the characteristics of patients with SAVS whose clinical presentation mimicked intracranial SAH caused by rupture of a saccular aneurysm.

Results

Thirty-five patients were identified after a review of the literature. In our SAH database, comprising 2142 patients included in the period 1985–2004, we found one patient (0.05%, 95 % CI 0.006–0.3%). SAH due to SAVS occurred at any age (4–72 years). The SAVS was located at the craniocervical junction in 14 patients, at the cervical level in 11, and at the thoracolumbar level in the remaining 11 patients. The majority of patients (n = 26, 72%) had no disabling deficits at discharge or follow-up.

Conclusion

Rupture of a SAVS presenting as intracranial SAH is rare and can occur at any age. The SAVS can be located not only at the craniocervical junction or cervical level but also in the thoracolumbar region. Most patients with SAVS presenting as intracranial SAH have a good recovery.

Case report: Profound hypotension associated with labetalol therapy in a patient with cerebral aneurysms and subarachnoid hemorrhage

PURPOSE

Labetalol is an effective antihypertensive medication frequently used to treat systemic hypertension in acute care settings, including the management of hypertension associated with a subarachnoid hemorrhage. We present a case of profound hypotension, refractory to inotropic and vasopressor therapy following an iv infusion of labetalol.

CLINICAL FEATURES

Initiation of an iv labetalol infusion resulted in good blood pressure control in a patient suffering from a Fisher grade 3 subarachnoid hemorrhage with an initial Glascow coma scale of 14/15 and mild hydrocephalus. Progressive deterioration of neurological symptoms and evidence of worsening hydrocephalus preceded the sudden development of profound hypotension (60/35 mmHg) and bradycardia with a minimum heart rate of 40 beats.min(-1). Initial resuscitative efforts included administration of intravascular fluid, hypertonic saline, atropine, adrenalin (more than 10 mg in divided doses) and noradrenalin. These measures restored the blood pressure to 80/45 with a HR of 98 beats.min(-1). Intraoperative placement of an intraventricular drain released cerebrospinal fluid under pressure with an initial intracranial pressure of 15 cm H(2)O. A combination of adrenalin, noradrenalin, dopamine and vasopressin infusions were required to restore the blood pressure to 130/65 mmHg after an additional two hours. All inotropic and vasopressor support was weaned off after the 14th hr (about two drug half-lives). The patient was awake and responsive the following day, with no obvious neurological consequences. No evidence of neurological injury, drug administration error or myocardial dysfunction was documented.

CONCLUSION

The episode of profound hypotension which occurred after initiating a labetolol infusion required maximal combined vasopressor therapy to restore the blood pressure suggesting that this patient demonstrated an extreme sensitivity to labetalol. Combination therapy with adrenergic and nonadrenergic agonists may be required for optimal treatment of profound hypotension associated with labetalol-induced vasoplegia.

[Spectral analysis of the ECG R-R interval permits early detection of vagal responses to neurosurgical stimuli]

OBJECTIVE

To assess the efficacy of ECG spectral analysis, compared with heart rate (HR) monitoring in the detection of vagal response to surgical stimuli.

METHODS

Twenty Asa II-III patients (age: 65 +/- 13 years) scheduled for surgery of cerebellopontine angle or implantation of sacral root stimulator were examined. Target controlled infusion of propofol (2-4 microg x ml(-1)) and remifentanil (4 ng x ml(-1)) was guided by the bispectral index (Bis). Arterial pressure via a radial catheter, pulse oximetry and end tidal CO2 were continuously monitored. Spectral analysis was achieved by connecting a computer to the cardiorespiratory monitor. Online power spectrum densities were calculated from the ECG R-R interval by software based on the fast Fourier transform (LabView, National Instruments, USA). Low frequency (LF: 0.04-0.15Hz) and high frequency (HF: 0.15-0.4Hz) were associated with sympathetic and parasympathetic activities respectively. We defined vagal reaction as a decrease in FC or an increase in HF >10% of the prestimuli value. HF and FC were compared according to the detection delay (by a Student t test with p < 0.05 considered significant) and a concordance test with a kappa coefficient (kappa): -1 = total discordance to 1 = total concordance.

RESULTS

Twelve vagal reactions (observed in 8 patients) were detected within 5.5 +/- 1.3 s (HF) and 12.4 +/- 1.6 (FC); p < 0.001. Concordance between the 2 parameters was 95% (kappa =0.9).

CONCLUSION

The ECG spectral analysis is a non-invasive technique, which permits the detection of intra-operative vagal reactions earlier than conventional monitoring of HR.