Kernohan-Woltman notch phenomenon: an exceptional neurological picture?

INTRODUCTION: Ipsilateral hemiparesis (IH) can be defined as a paradoxical dysfunction of the first motor neuron involving the extremities on the opposite side to that expected, given the location of the triggering intracranial pathology. Compression of the corticospinal tract (CSt) along its course through the contralateral cerebral peduncle against the free edge of the tentorium, known as the Kernohan-Woltman notch phenomenon (KWNP), represents the main cause of IH. METHODS: This retrospective study analyses a series of 12 patients diagnosed with IH secondary to KWNP treated at our institution, including a descriptive study of epidemiological, clinical, radiological, neurophysiological, and prognostic variables. RESULTS: In 75% of the cases, symptoms had an acute or subacute onset. Initial imaging studies showed signs of significant mass effect in half of the patients, whereas magnetic resonance imaging (MRI) identified a structural lesion in the contralateral cerebral peduncle in two thirds of them. Impairment of the motor evoked potentials (MEP) was verified in 4 patients. During follow-up 7 patients experienced improvement in motor activity, and near half of the cases were classified in the first three categories of the modified Rankin scale. CONCLUSIONS: In contrast to prior historical series, most of our patients developed a KWNP secondary to a traumatic mechanism. MRI represents the optimal method to identify both the classic cerebral peduncle notch and the underlying structural lesion of the CSt. The use of MEP can help to establish the diagnosis, especially in those cases lacking definite radiological findings.

Effect of pituitary adenoma consistency on surgical outcomes in patients undergoing endonasal endoscopic transsphenoidal surgery.

BACKGROUND: Most pituitary adenomas (PAs) are considered to have a soft tumor consistency. However, there is a non-negligible percentage (5-13%) of tumors presenting or exhibiting a fibrous consistency that would entail a more difficult and complicated surgical excision with higher surgical morbidity and mortality rates. PURPOSE: To analyze the clinical consequences of PA tumor consistency on the surgical outcomes in patients undergoing endonasal endoscopic transsphenoidal (EET) pituitary surgery. METHODS: An ambispective study of patients with PAs operated on through an EET approach in two Spanish tertiary hospitals over the last 12 years. A total of 226 consecutive interventions were carried out in the Neurosurgery Departments of the Hospital Universitario Ramón y Cajal (HURC) and the Hospital Universitario Puerta del Sur by the same neurosurgeon. PAs were grouped into soft (n = 150) and fibrous (n = 76). All patients underwent hormonal and magnetic resonance imaging (MRI) studies before and after surgery. In addition, neurosurgical complications were recorded in each patient. RESULTS: Fibrous adenomas were independently associated with lower resection rates compared to soft adenomas (fibrous gross total resection [GTR] rate 48.7% vs. 76.3%, p < 0.001), even in those adenomas without invasion of the cavernous sinus (Knosp grades 0, I, and II). There were more intraoperative cerebrospinal fluid (CSF) leaks in patients with fibrous PAs. Moreover, fibrous PAs showed higher rates of postoperative hypopituitarism, permanent diabetes insipidus (DI) and postoperative treatments (hormonal treatment and radiotherapy). The excision of a fibrous PA required a longer surgical time (22.5 min more than soft PAs, p = 0.014), regardless of other factors. CONCLUSION: The consistency of the PAs significantly conditions both the results of surgery (lower resections rates), complications (higher incidence of postoperative hypopituitarism, permanent DI), and the prognosis (higher incidence of postoperative treatments) of the patient undergoing EET.

Is it possible to predict the development of diabetes insipidus after pituitary surgery? Study of 241 endoscopic transsphenoidal pituitary surgeries.

PURPOSE: To identify presurgical and surgical factors associated with the development of diabetes insipidus (DI) after pituitary adenoma (PA) resection through an endoscopic endonasal transsphenoidal approach. METHODS: Data from 231 patients with functioning and non-functioning PAs who underwent an endoscopic endonasal transsphenoidal approach in the last ten years. RESULTS: 231 patients with 241 pituitary surgeries were included. Eighty-five percent harbored macroadenomas and 38.1% of them were invasive. After pituitary surgery, 12.5% (n = 30) developed transient DI and 5.0% (n = 12) permanent DI. The global risk of DI was higher in patients younger than 65 years (OR = 2.94, p = 0.029), with total tumoral resection (OR = 2.86, p = 0.007) and with diaphragm opening during pituitary resection (OR = 3.63, p = 0.0003). Once postoperative DI developed, the risk of permanent DI increased in those patients with larger PA (OR = 1.07 for each mm of craniocaudal diameter, p = 0.020), especially in those greater than 30 mm (OR = 8.33, p = 0.004). Moreover, diaphragm opening during pituitary resection (OR = 28.3, p = 0.018) predicted long-term DI independently of pituitary tumor size. The risk of permanent DI increased as PA craniocaudal diameter increased (r = 0.20, p = 0.002). CONCLUSION: In patients with PAs younger than 65 years, in whom diaphragm has been opened during pituitary surgery and/or with a total tumor resection, special hydric balance monitoring should be maintained in the postoperative period due to the increased risk of developing DI. The risk of permanent DI increases as PA craniocaudal diameter increased.

Predictive model of surgical remission in acromegaly: age, presurgical GH levels and Knosp grade as the best predictors of surgical remission.

PURPOSE: To identify presurgical clinical, hormonal and radiological variables associated with surgical remission in acromegaly and develop a predictive model for surgical remission. METHODS: Ambispective study of acromegaly surgical patients followed in two Spanish tertiary hospitals. Patients operated by the same neurosurgeon by endonasal endoscopic transsphenoidal approach (n = 49) were included to develop the predictive model, and patients operated by other neurosurgeons (n = 37) were used for external validation of the predictive model. The predictive model was developed with a multivariate logistic regression model based on the 2000 criteria. RESULTS: 86 acromegalic patients were included. 49 patients, 83.7% with macroadenomas and 32.7% with Knosp grade > 2, were included for the development of the predictive model. The overall rate of surgical remission with the 2000 criteria was 73.5% and 51.0% with the 2010 criteria. Using the 2000 criteria, variables associated with surgical remission were: older age (OR = 1.1, p = 0.001), lower basal presurgical GH levels (OR = 0.9, p = 0.003), Knosp 0-2 (OR = 34.1, p < 0.0001) and lower maximum pituitary adenoma diameter (OR = 0.9, p = 0.019). The model with the best diagnostic accuracy to predict surgical remission combined age, Knosp 0-2 and presurgical GH levels (AIC = 29.7, AUC = 0.95) with a sensitivity of 93.8% and a specificity of 75.0%. The estimated loss of prediction with the external validation (n = 37) was 4.2%. CONCLUSION: The predictive model with the best diagnosis accuracy for surgical remission combined age, Knosp 0-2 and presurgical GH levels, with a sensitivity of 93.8% and a specificity of 75.0%. This model could be very useful to select candidates to preoperative medical treatment and planning the follow-up.