Hemodynamic and electrolyte changes in patients undergoing neuroendoscopic procedures

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.

Spinal cord hypothermia without systemic hypothermia

BACKGROUND AND PURPOSE

Hypothermia has been shown to be beneficial in the setting of acute SCI. However, widespread use has been hindered by the need for systemic hypothermia as the vehicle for achieving spinal cord hypothermia. This study demonstrates that localized spinal cord hypothermia can be achieved via a percutaneous approach while maintaining systemic normothermia.

MATERIALS AND METHODS

Five Yucatan swine underwent catheterization of the subarachnoid space and infusion of room temperature, chilled, and iced PL solutions into the cervical spinal canal, with drainage from the lumbar canal. Thermocouples were placed within the spinal cord and in the subarachnoid space and recorded during infusions and recovery from hypothermia.

RESULTS

Results demonstrated that hypothermia as low as 16.8°C is feasible in the spinal cord with retention of systemic normothermia, with strong (r = 0.95) correlation between the spinal cord temperature and the CSF temperature. Degrees of cooling varied with flow rates and with infusate temperature.

CONCLUSIONS

While the data are preliminary in a small group of animals, the ability to rapidly create a wide range of controlled spinal cord hypothermia while preserving normal body temperature warrants wider exploration. The study also indicates that further investigation of the hypothesis that CSF temperature monitoring may be an acceptable surrogate for direct spinal cord temperature monitoring should be pursued.

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.

Possible detrimental effects of neurosurgical irrigation fluids on neural tissue: an evidence based analysis of various irrigants used in contemporary neurosurgical practice

Physiological saline and other solutions used as irrigation fluids during neurosurgical procedures have long been debated to cause adverse effects on neural tissue. Laboratory based research over the past fifty years has described the possible harm caused to central nervous system cells by normal saline, and has advocated the use of safer alternatives such as lactated Ringer's solution and artificial cerebrospinal fluid. However, there is a dearth of corresponding clinical studies to support this standpoint. Worldwide, normal saline remains the most widely used neurosurgical irrigation fluid. We have attempted to document the preference of practicing neurosurgeons worldwide regarding the irrigation fluids via an electronic mail survey, and have analyzed the available evidence on the relative safety of various irrigation fluids. We recommend the use of lactated Ringer's solution and artificial cerebrospinal fluid as neurosurgical irrigants, especially during neuroendoscopy and longer procedures requiring application of copious amount of irrigation fluid.

Complications of endoscopic third ventriculostomy

OBJECTS

Although endoscopic third ventriculostomy (ETV) is considered as the first choice in the management of noncommunicating hydrocephalus, it is not without risk or complication.

METHODS

The patients who had undergone ETV only between 1998 and 2005 were retrospectively reviewed. There were 85 males and 70 females, and 173 ETVs were performed in 155 patients. The patients' age ranged from 2 months to 77 years. Complications were categorized as (1) intraoperative, (2) early postoperative (<1 month), and (3) late postoperative (>1 month). Follow-up of the patients ranged from 1 to 86 months.

RESULTS

Overall complication rate per patient was 15.4%, and complication per procedure was 18%. Complication rate significantly varied with the etiology of hydrocephalus (P = 0.013). The patients with Chiari type I malformation and tumor had no or very low complication rates. The complication risk was significantly higher in repeat endoscopic procedure (55.5%) than in the first procedure (10%; P = 0.0001).

CONCLUSION

ETV should be the first choice in the management of noncommunicating hydrocephalus. Training, experience, and meticulous technique will decrease the complication rate. Patients undergoing ETV should be followed in a similar manner to patients with cerebrospinal fluid shunts.