Anesthesia for Minimally Invasive Cranial and Spinal Surgery

Potential Neuroendoscopic Complications: An Anesthesiologist's Perspective

Endoscopic techniques are being used extensively used in the current times for the diagnosis and treatment of numerous intracranial pathologies. Although the morbidity associated with these procedures is lower as compared to other conventional surgical modalities, neuroendoscopic techniques have its own fair share of distinct complications such as bleeding, cerebrospinal fluid leakage, and subdural hematoma. However, certain specific complication fall within the purview of the attending anesthesiologist who should remain vigilant, anticipating these problems to occur and should be well equipped to deal with such contingencies. This review attempts to sensitize the anesthesiologists regarding the well-known as well as rare complications of intracranial neuroendoscopic procedures and to familiarize them with their diverse presentations, preventive strategies, and management protocols.

Total intravenous versus inhaled anesthesia in transsphenoidal tumor surgery

PURPOSE

Visualization of the surgical field is essential for patient safety during endoscopic transsphenoidal tumor surgery. In this retrospective chart review and data analysis of patients undergoing endoscopic transsphenoidal resection of pituitary tumors under general anesthesia we sought to determine if total intravenous anesthesia with propofol and remifentanil leads to decreased bleeding, surgical duration, time to extubation and/or length of stay in the recovery room compared to inhaled anesthesia with sevoflurane or desflurane.

METHODS

After IRB approval, chart reviews of 193 American Society of Anesthesiologists class 1 to 3 patients were conducted who had undergone transsphenoidal, endonasal resections of pituitary tumors under total intravenous or inhaled anesthesia at an academic teaching hospital in the United States over a seven-year time period. One hundred four patients fulfilled the inclusion criteria and were further reviewed. Primary outcome was intraoperative blood loss; secondary outcomes were surgical duration, time to extubation and length of stay in the recovery room.

RESULTS

Gender, age, and Lund-Mackay-Scores were equally distributed between the two anesthetic groups. We found no significant effect of the anesthetic technique, age, gender, or Lund Mackay score on any of the primary or secondary outcomes. The only significant predictor for recovery room length of stay was intraoperative blood loss.

CONCLUSION

Our study shows no evidence that total intravenous anesthesia is superior to inhaled anesthesia or vice versa during endoscopic transsphenoidal sinus surgery with regard to relevant clinical outcome parameters.

Venous Air Embolism During Endoscopic Third Ventriculostomy

Neuroendoscopic procedures are increasingly performed nowadays due to the significant technological improvement of endoscopic instrumentation. It carries various advantages such as speed, simplicity, avoidance of implants, and no brain dissection or retraction. Although considered to be safe, it is associated with a host of complications. We hereby report a case of venous air embolism in an infant who was undergoing endoscopic third ventriculostomy. The complication occurred at the completion of surgery when surgeons were withdrawing the endoscope. The successful management of this uncommon event is being discussed.

Anesthesia for Endoscopic Third Ventriculostomy in Children

Neuroendoscopy has established itself as a routine neurosurgical procedure in pediatric population. To have an uneventful smooth perioperative course, it is important for anesthesiologist to know about the key steps, possible complications, and specific anesthetic requirements. Among neuroendoscopies, endoscopic third ventriculostomy is the commonly performed one.

Anesthesiologic regimen and intraoperative delirium in deep brain stimulation surgery for Parkinson's disease

BACKGROUND

In many centers the standard anesthesiological care for deep brain stimulation (DBS) surgery in Parkinson's disease patients is an asleep-awake-asleep procedure. However, sedative drugs and anesthetics can compromise ventilation and hemodynamic stability during the operation and some patients develop a delirious mental state after the initial asleep phase. Further, these drugs interfere with the patient's alertness and cooperativeness, the quality of microelectrode recordings, and the recognition of undesired stimulation effects. In this study, we correlated the incidence of intraoperative delirium with the amount of anesthetics used intraoperatively.

METHODS

The anesthesiologic approach is based on continuous presence and care, avoidance of negative suggestions, use of positive suggestions, and utilization of the patient's own resources. Clinical data from the operations were analyzed retrospectively, the occurrence of intraoperative delirium was extracted from patients' charts. The last 16 patients undergoing the standard conscious sedation procedure (group I) were compared to the first 22 (group II) psychologically-guided patients.

RESULTS

The median amount of propofol decreased from 146 mg (group I) to 0mg (group II), remifentanyl from 0.70 mg to 0.00 mg, respectively (P<0.001 for propofol and remifentanyl). Using the new procedure, 12 of 22 patients (55%) in group II required no anesthetics. Intraoperative delirium was significantly less frequent in group II (P=0.03).

CONCLUSIONS

The occurrence of intraoperative delirium correlates with the amount of intraoperative sedative and anesthetic drugs. Sedation and powerful analgesia are not prerequisites for patients' comfort during awake-DBS-surgery.

Avoidance and management of perioperative complications of endoscopic third ventriculostomy: the Dhaka experience

OBJECT

Although endoscopic third ventriculostomy (ETV) is a minimally invasive procedure, serious perioperative complications may occur due to the unique surgical maneuvers involved. In this paper the authors report the complications of elective and emergency ETV and their surgical management in 412 patients from July 2006 to October 2012 at Dhaka Medical College Hospital (a government hospital) and other private hospitals in Dhaka, Bangladesh. The authors attempted some previously undescribed simple maneuvers that may help to overcome the difficulties of managing complications.

METHODS

The complication rate was determined by recording intraoperative changes in pulse and blood pressure, bleeding episodes, serum electrolyte abnormalities, CSF leakage, and neurological deterioration in the immediate postoperative period.

RESULTS

Intraoperative complications included hemodynamic alterations in the form of tachycardia, bradycardia, and hypertension. Bleeding was categorized as major in 2 cases and minor in 68 cases. Delayed recovery from anesthesia occurred in 14 cases, CSF leakage from the wound in 11 cases, and electrolyte imbalance in 5 cases. Postoperatively, 2 patients suffered convulsions and 1 had evidence of third cranial nerve injury. Three patients died as a result of complications.

CONCLUSIONS

Complications during endoscopy can lead to serious consequences that may sometimes be very difficult to manage. The authors have identified and managed a large number of complications in this series, although the rate of complications is consistent with that in other reported series. These complications should be kept in mind perioperatively by both surgeons and anesthesiologists, as prompt detection and action can help minimize the risks associated with neuroendoscopic procedures.

Preservation of microelectrode recordings with non-GABAergic drugs during deep brain stimulator placement in children

OBJECT

Deep brain stimulation (DBS) has become accepted therapy for intractable dystonia and other movement disorders. The accurate placement of DBS electrodes into the globus pallidus internus is assisted by unimpaired microelectrode recordings (MERs). Many anesthetic and sedative drugs interfere with MERs, requiring the patient to be awake for target localization and neurological testing during the procedure. In this study, a novel anesthetic technique was investigated in pediatric DBS to preserve MERs.

METHODS

In this paper, the authors describe a sedative/anesthetic technique using ketamine, remifentanil, dexmedetomidine, and nicardipine in 6 pediatric patients, in whom the avoidance of GABAergic stimulating drugs permitted excellent surgical conditions with no detrimental effects on intraoperative MERs. The quality of the MERs, and the frequency of its use in making electrode placement decisions, was reviewed.

RESULTS

All 6 patients had good-quality MERs. The data were of sufficient quality to make a total of 9 trajectory adjustments.

CONCLUSIONS

Microelectrode recordings in pediatric DBS can be preserved with a combination of dexmedetomidine and ketamine, remifentanil, and nicardipine. This preservation of MERs is particularly crucial in electrode placement in children.

Preoperative and postoperative anesthetic and analgesic techniques for minimally invasive surgery of the spine

STUDY DESIGN

A review of methods to optimize anesthesia and analgesia for minimally invasive spine procedures.

OBJECTIVE

To provide information to surgeons and anesthesiologists of methods to provide optimal anesthesia and pain control for minimally invasive spine surgery with an emphasis on preoperative planning.

SUMMARY OF BACKGROUND DATA

Postoperative pain management in patients undergoing minimally invasive spine surgery is a challenge for the perioperative anesthesiologist. In addition to the incisional pain, trauma to deeper tissues, such as ligaments, muscles, intervertebral discs, and periosteum are reasons for significant pain. The increasing number of minimally invasive surgeries and the need for improved and rapid return of the patient of functionality have brought the perioperative anesthesiologist and the surgeon closer.

METHODS

We undertook a review of the literature currently available on anesthesia and analgesia for minimally invasive spine surgery with an emphasis on preoperative planning. A large number of reports of randomized controlled clinical trials with respect to perioperative anesthetic and postoperative pain management for minimally invasive spine surgery are reviewed and the applicability of some of the principles and protocols used for other types of minimally invasive surgical procedures are placed in the context of spine surgery.

RESULTS

It is important to understand and implement a multimodal analgesic therapy during a patient's preoperative visits. Perioperative multimodal analgesia with a fast-track anesthetic protocol is also important and provided in the manuscript. This protocol poses a challenge to the anesthesiologist with respect to neurophysiologic monitoring, which requires further study. The postoperative analgesic management should be a continuance of the multimodal analgesia provided before surgery. Some drugs are not appropriate for patients undergoing fusion surgery because of their effect on bone healing.

CONCLUSION

An optimal preoperative, perioperative, and postoperative anesthesia and analgesia protocol is important to best possible pain relief and rapid return to normal function. Communication between the anesthesiologist and spine surgeon is important to achieve a protocol with the best short- and long-term outcomes for the benefit of the patient.

Endoscopic strip craniectomy in early infancy: the initial five years of anesthesia experience

BACKGROUND

Minimally invasive endoscopic strip craniectomy (ESC) is a relatively new surgical technique for treating craniosynostosis in early infancy. In this study we reviewed our anesthesia experience with ESC. The hypothesis was that infants with low body weight and syndromes would have a higher risk of perioperative blood transfusion and that those with respiratory complications are more likely to be admitted to the intensive care unit (ICU).

METHODS

We retrospectively reviewed patient charts and anesthesia records of the first 100 consecutive infants who underwent ESC between May 2004 and December 2008 and follow-up evaluations until December 2009. Outcomes included (a) perioperative blood transfusion, (b) venous air embolism (VAE), (c) ICU admission, and (d) reoperation with craniofacial reconstruction procedures. Multivariable logistic regression was used to determine significant factors of patient outcomes.

RESULTS

Infants ranging from 4 to 34 weeks of age (weight: 3.2 to 10.1 kg), presented for 87 single and 13 multiple ESC. Four infants had a craniofacial syndrome. The mean surgical time was 48 minutes (range: 26 to 86 minutes). Ninety-two infants had a median estimated blood loss of 23 mL (interquartile ranges [IQR]: 15 to 30 mL). Eight infants who required blood transfusion received a median amount of 17.2 mL/kg (IQR: 10.1 to 21.2 mL/kg). Body weight ≤5 kg (P = 0.04), sagittal ESC (P < 0.01), syndromic craniosynostosis (P < 0.01), and earlier date of surgery in the series (P < 0.01) were factors associated with blood transfusion. VAE was detected in 2 infants with no changes in clinical outcome. Eight infants were admitted to the ICU. Factors associated with ICU admission were blood transfusion (P < 0.001) and respiratory complications (P < 0.001). Eighty-two infants were discharged on postoperative day 1 (range: 1 to 3 days). Six infants underwent subsequent fronto-orbital advancement and 1 cranial vault reconstruction. Multiple-suture craniosynostosis (P < 0.01), associated syndromes (P = 0.03), and ICU admission after ESC (P = 0.04) were predictive of reoperation.

CONCLUSIONS

Twenty percent of infants undergoing ESC had 1 or more of the following: need for blood transfusion, VAE, respiratory complications, and ICU admission. Multivariable analysis confirmed that patients with lower body weight, those with earlier date of surgery in the series, those undergoing sagittal ESC, and those with syndromic craniosynostosis had a higher rate of blood transfusion. ICU admissions often occurred in infants requiring transfusion and those with respiratory complications. Infants with multiple-suture craniosynostosis were more likely to require subsequent craniofacial reconstruction procedures.

Anaesthesia for endoscopic neurosurgical procedures

PURPOSE OF REVIEW

Endoscopic neurosurgical procedures are becoming more frequent and popular in the treatment of intracranial disease. When endoscopy involves the intraventricular structures, irrigating solutions are required and may contribute to sudden and sharp increases in intracranial pressure. More recently, nasal endoscopic approach has been used to perform skull base surgery for aneurysms and tumours. We have analysed published articles in order to detect anaesthesia management and perioperative complications.

RECENT FINDINGS

Sudden and dangerously low decreases in cerebral perfusion pressures do not provoke the 'traditional Cushing's response' usually associated with significantly high intracranial pressure. It is important to note that tachycardia (not bradycardia) and/or hypertension are the most frequent haemodynamic complications during neuroendoscopic procedures. With the transnasal approach severe intraoperative haemorrhage is the most important complication to consider followed by direct injury to surrounding neural structures.

SUMMARY

Invasive arterial blood pressure and intracranial pressure should be measured continuously during neuroendoscopies to detect early intraoperative cerebral ischaemia instead of waiting for the appearance of bradycardia which may be a late sign. General anaesthesia remains the technique of choice. Intracranial haemorrhage increases the likelihood of perioperative complications. Close postoperative monitoring is required to diagnose and treat complications such as convulsions, persistent hydrocephalus, haemorrhage or electrolytic imbalance.

[Bone resin based vertebral augmentation: form of anesthesia and systemic complications]

Over the last few years bone resin based vertebral augmentation in the form of vertebro- and kyphoplasty has proved to be a safe therapeutic option in cases of vertebral compression fractures. Nevertheless, rare systemic complications have been seen, i.e., pulmonary embolisms ranging from harmless to lethal.The presence of an anesthesiologist can be especially useful in cases of systemic complications. Whether the form of anesthesia has any influence on the outcome of vertebro- or kyphoplasty is currently unknown. Local anesthesia supplemented by analgosedation is often used as an alternative to general anesthesia. The rationale for one or the other form of anesthesia can be factors like type of augmentation (vertebro- or kyphoplasty), number of vertebral levels to be treated as well as the patient's age, condition, and comorbidities.Single-shot epidural anesthesia is yet another anesthetic option that has been successfully used in our clinic for some years now. It combines the advantages of general and local anesthesia: excellent segmental analgesia even in multilevel cases in awake and responding patients.

[Scalp blocks. A useful technique for neurosurgery, dermatology, plastic surgery and pain therapy]

Safe and effective cranial analgesia can be achieved by blocking the sensitive nerves of that region. These include the supraorbital nerve, the supratrochlear nerve, the zygomaticotemporal nerve, the auriculotemporal nerve and the greater and lesser occipital nerves which are accessible at typical and most proximal points. Preferably long acting local anesthetics such as ropivacaine 0.75% or levobupivacaine 0.5% are used supplemented with 5 microg/ml epinephrine to reduce systemic resorption and to elongate the duration. Scalp blocks are useful for intraoperative neurologic testing of the patient during awake craniotomy or for supplementation of general anesthesia for other forms of craniotomy. Other applications are minimally invasive and stereotactic neurosurgery including deep brain stimulation, photodynamic therapy of actinic ceratosis, cranial plastic surgery and pain therapy.

Influence of an increased intracranial pressure on cerebral and systemic haemodynamics during endoscopic neurosurgery: an animal model

BACKGROUND

During endoscopic neurosurgery, direct mechanical stimulation of the brain by the endoscope and increased intracranial pressure (ICP) caused by the continuous rinsing can induce potentially lethal haemodynamic reflexes, brain ischaemia, and excessive fluid resorption.

METHODS

In a newly presented rat model of endoscopic neurosurgery, stereotactic access to the cerebrospinal fluid was secured and the ICP was increased by controlled infusion until complete suppression of the cerebral perfusion pressure (CPP). The haematocrit (Hct) level was determined before and after the procedure. During the whole procedure, invasive arterial pressure, ICP, and heart rate were continuously recorded and evaluated in a subsequent offline analysis. After the procedure, the animals were allowed to recover and 7 days later they were killed for histological examination.

RESULTS

Suppression of the CPP resulted in a severe hypertension combined with tachycardia or mild bradycardia. The Hct decreased from 41 to 35 over the minutes of CPP suppression. After cessation of the infusion, the ICP decreased to 37% of the plateau pressure within 2.5 s. In the first few minutes after restoration of normal ICP, five animals died because of pulmonary oedema.

CONCLUSIONS

Upon complete suppression of the CPP, an obvious hypertension developed, often together with tachycardia, but no severe bradycardia. At high ICP levels, we observed an important translocation of irrigation fluid to the vascular space. Fatality was not caused by ischaemia or arrhythmia but due to pulmonary oedema.