Surgical limits in transnasal approach to opticocarotid region and planum sphenoidale: an anatomic cadaveric study.

BACKGROUND: The significance of medial and lateral opticocarotid recesses and the planum sphenoidale region in skull base pathologies for the transsphenoidal-transplanum approach were evaluated. METHODS: The sphenoid bone block samples were extracted from adult cadavers. Dissections and measurements in the opticocarotid and planum sphenoidale regions were performed in 29 samples using a surgical microscope. For histologic evaluation, oblique sections through the bilateral opticocarotid regions were obtained and examined in eight samples. RESULTS: Optic, carotid prominences, and medial and lateral opticocarotid recesses can be identified as lateral markers intraoperatively to the extent of the exposure. The lateral opticocarotid recess was observed to be prominent in all samples. In all samples, the groove formed by optic and carotid prominences between the medial and lateral opticocarotid recesses was seen. This groove was designated the inter-recess sulcus. In the transsphenoidal-transplanum approach, the area needed for a reliable bone resection was measured as a mean of 237.32 ± 30.96 mm(2). The mean angle between optic nerves was 115.41 ± 18.39 degrees. The mean anteroposterior length of the planum sphenoidale was 14.84 ± 1.52 mm. In histologic sections, collagenous ligaments between the anterior part of cavernous sinus and the adventitia layer of internal carotid artery were more frequent and regular than the inferior part of optic nerve. CONCLUSIONS: The lateral opticocarotid recess is a reliable and persistent indicator for extended transsphenoidal surgery. To approach the opticocarotid region near the internal carotid artery and optic nerve, a careful dissection is needed to minimize surgical injuries to the optic nerve and carotid artery. Other factors determining a reliable bone resection are the anteroposterior length of the planum sphenoidale and the distance and width of the angle between optic nerves. Attention should be given to individual anatomic variations of the region when planning and performing transsphenoidal-transplanum surgery.

Analysis of intracranial pressure changes during early versus late percutaneous tracheostomy in a neuro-intensive care unit.

BACKGROUND: We aimed to investigate intracranial pressure (ICP) changes during early versus late bedside percutaneous tracheostomy (PT) in a neuro-intensive care unit (NICU). METHODS: This study included 30 patients admitted to our NICU for head trauma, subarachnoid haemorrhage, intracerebral haematoma or brain tumour with a Glasgow Coma Score (GCS) less than 8. These patients also underwent ICP monitoring. Bedside PT was performed either early (within 7 days of ventilation) or late (after 7 days of ventilation) via the Griggs system. In all patients; ICP, systemic blood pressure, heart rate, oxygen saturation (Sat O(2)) and arterial blood gases were recorded 5 min before the procedure, during skin incision, during tracheal cannulation, as well as 5 min and 10 min after the procedure. FINDINGS: Thirty patients, 18 male and 12 female, with various intracranial pathologies between ages 18 and 78 (mean 38.7 +/- 20) were identified. The admission GCS ranged between 4 and 11 (median 7). Physiological variables did not differ significantly between the two groups. In the early group, ICP values measured 5 min before the procedure, during skin incision, during tracheal cannulation, as well as 5 min and 10 min after the procedure were 15.1 +/- 5.2, 22 +/- 10.1, 28.4 +/- 13.7, 17.3 +/- 7.1, 13.8 +/- 5.0 mmHg, respectively. In the late group, these values were 14.2 +/- 4.5, 17.2 +/- 5.5, 21.5 +/- 8.0, 15.1 +/- 5.3 and 12.4 +/- 4.1 mmHg. There was no significant difference between the early or late groups in terms of ICP increases during these predetermined 5 time points. CONCLUSIONS: In patients with decreased intracranial compliance, a relatively minimally invasive procedure such as PT may lead to significant increases in ICP. The timing of PT does not seem to influence ICP, mortality, pneumonia or early complications. During the PT procedure, ICP should be closely monitored and preventive strategies should be instituted in an attempt to prevent secondary insult to an already severely injured brain.