Rudolf Fahlbusch and Amir Samii
Hussam Metwali, Venelin Gerganov and Rudolf Fahlbusch
Preservation of the pituitary stalk and its vasculature is a key step in good postoperative endocrinological outcome in patients with craniopharyngiomas. In this article, the authors describe the surgical technique of medial optic nerve mobilization for better inspection and preservation of the pituitary stalk.
This operative technique has been applied in 3 patients. Following tumor exposure via a frontolateral approach, the pituitary stalk could be seen partially hidden under the optic nerve and the optic chiasm. The subchiasmatic and opticocarotid spaces were narrow, and tumor dissection from the pituitary stalk under direct vision was not possible. The optic canal was therefore unroofed, the falciform ligament was incised, and the lateral part of the tuberculum sellae was drilled medial to the optic nerve. The optic nerve could be mobilized medially to widen the opticocarotid triangle, which enhanced visualization of and access to the pituitary stalk.
By using the optic nerve mobilization technique, the tumor could be removed completely, and the pituitary stalk and its vasculature were preserved in all patients. In 2 patients, vision improved after surgery, while in 1 patient it remained normal, as it was before surgery. The hormonal status remained normal after surgery in 2 patients. In the patient with preoperative hormonal deficiencies, improvement occurred early after surgery and hormonal levels were normal after 3 months. No approach-related complications occurred.
This early experience shows that this technique is safe and could be used as a complementary step during microsurgery of craniopharyngiomas. It allows for tumor dissection from the pituitary stalk under direct vision. The pituitary stalk can thus be preserved without jeopardizing the optic nerve.
Tomoki Todo and Rudolf Fahlbusch
✓ In order to elucidate some of the signal transduction processes in human meningioma cells, the authors studied the effect of epidermal growth factor (EGF) and bromocriptine on inositol phospholipid hydrolysis, using low-passage human meningioma cells in culture. Epidermal growth factor is a well-studied mitogenic factor for meningioma cells, whereas bromocriptine is known to have an inhibitory effect on meningioma cell proliferation. The addition of EGF to meningioma cells caused stimulation of inositol phosphate accumulation in a dose-dependent manner at 60 minutes posttreatment, with the maximum effect (120% to 167% of control) achieved at a concentration of 10 ng/ml. Extraction of separate inositol phosphates revealed that inositol monophosphate (IP1) and inositol bisphosphate (IP2), but not inositol trisphosphate (IP3), accounted for the increase at 60 minutes. Kinetic analysis of EGF-stimulated inositol phospholipid hydrolysis showed that a sharp and transient increase in IP3 from 5 to 12 minutes post-EGF and a transient but more gradual increase in IP2 from 2 to 12 minutes post-EGF were followed by a gradual and steady increase in IP1, which was significantly greater than control after 5 minutes. On the other hand, long-term studies showed a down-regulation of inositol phosphate accumulation (a 64% decrease vs. control) after 7 days of treatment with EGF (10 ng/ml). Bromocriptine (5 µM) exhibited no significant effect on inositol phosphate accumulation at 60 minutes in four of five meningiomas studied. However, of two meningiomas studied with bromocriptine in combination with EGF, both showed a significant additive increase in inositol phosphate accumulation compared to those treated with EGF alone. The results suggest a close involvement of inositol phospholipid turnover in human meningioma cells in response to mitogenic stimulation by EGF.
Rudolf Fahlbusch and Werner Schott
Object. The authors reviewed 47 cases of suprasellar meningiomas with special attention to ophthalmological and endocrinological outcomes.
Methods. All patients underwent surgery performed via a unilateral pterional approach between January 1983 and January 1998. Ophthalmological and endocrinological examinations were performed before the operation as well as 1 week and 3 months postoperatively. A special scoring system was adopted to quantify the extent of ophthalmological disturbances. Complete tumor resection was possible in all but one patient. There were no fatalities and the rate of visual improvement was 80%. The best prognoses were found in patients younger than 50 years and in patients in whom the duration of symptoms was less than 1 year. Before surgery, tumor-related endocrine disturbances were present in only three women who suffered from secondary hypogonadism; two of these patients recovered after surgery. Postoperatively, no patient needed replacement therapy for pituitary dysfunction. The overall tumor recurrence rate was 2.1% (one of 47 cases). For patients in whom long-term (> 5 years) follow-up data were available, the recurrence rate was 4.2% (one of 24 cases).
Conclusions. In this series, complete resection of suprasellar meningiomas was possible through a unilateral pterional craniotomy and was associated with a low morbidity rate and no deaths.
Johann Romstöck, Christian Strauss and Rudolf Fahlbusch
Object. Electromyography (EMG) monitoring is expected to reduce the incidence of motor cranial nerve deficits in cerebellopontine angle surgery. The aim of this study was to provide a detailed analysis of intraoperative EMG phenomena with respect to their surgical significance.
Methods. Using a system that continuously records facial and lower cranial nerve EMG signals during the entire operative procedure, the authors examined 30 patients undergoing surgery on acoustic neuroma (24 patients) or meningioma (six patients). Free-running EMG signals were recorded from muscles targeted by the facial, trigeminal, and lower cranial nerves, and were analyzed off-line with respect to waveform characteristics, frequencies, and amplitudes. Intraoperative measurements were correlated with typical surgical maneuvers and postoperative outcomes.
Characteristic EMG discharges were obtained: spikes and bursts were recorded immediately following the direct manipulation of a dissecting instrument near the cranial nerve, but also during periods when the nerve had not yet been exposed. Bursts could be precisely attributed to contact activity. Three distinct types of trains were identified: A, B, and C trains. Whereas B and C trains are irrelevant with respect to postoperative outcome, the A train—a sinusoidal, symmetrical sequence of high-frequency and low-amplitude signals—was observed in 19 patients and could be well correlated with additional postoperative facial nerve paresis (in 18 patients).
Conclusions. It could be demonstrated that the occurrence of A trains is a highly reliable predictor for postoperative facial palsy. Although some degree of functional worsening is to be expected postoperatively, there is a good chance of avoiding major deficits by warning the surgeon early. Continuous EMG monitoring is superior to electrical nerve stimulation or acoustic loudspeaker monitoring alone. The detailed analysis of EMG-waveform characteristics is able to provide more accurate warning criteria during surgery.
Hussam Metwali, Mario Giordano, Katja Kniese and Rudolf Fahlbusch
The aim of this study was to test the prognostic significance of intraoperative changes in the fractional anisotropy (FA) and the volume of the optic chiasma and their correlation with visual outcome.
Twenty-eight sequential patients with suprasellar tumors presenting with chiasma compression syndrome were surgically treated under intraoperative MRI control between March 2014 and July 2016. The FA and the volume of the optic chiasma were measured immediately before and immediately after tumor resection. The visual impairment score (VIS) was used to quantify the severity of the ophthalmological disturbances before surgery, 10–14 days after surgery, and again 3 months thereafter. The change in the FA and the volume of the optic chiasma was correlated to the improvement of vision. The correlation between other predictors such as the age of the patients and the duration of symptoms and the visual outcome was tested.
The VIS improved significantly after surgery. The FA values of the optic chiasma decreased significantly after decompression, whereas the volume of the optic chiasma increased significantly after decompression. The early and delayed improvement of vision was strongly correlated to the decrease in the average FA and the increase of the volume of the optic chiasma. The duration of symptoms showed a significant negative correlation to the visual outcome. However, the decrease in the FA showed the strongest correlation to the improvement of the VIS, followed by the expansion of the optic chiasma, and then the duration of symptoms.
The decrease in the FA and the expansion of the optic chiasma after its decompression are strong early predictors of the visual outcome. These parameters are also able to predict delayed improvement of vision.
Uwe M. H. Schrell, Panos Nomikos and Rudolf Fahlbusch
✓ Preliminary studies have shown that the dopamine D1 receptor is expressed in cerebral meningioma tissue. The current study presents evidence that the iodinated dopamine D1 antagonist [125I]SCH-23982 bound to dopamine binding sites in 33 of the 45 human cerebral meningiomas examined for this. Saturation curves and the linearity of the Scatchard analysis indicate that [125I]SCH-23982 binds to a homogeneous population of binding sites. Competition curves reveal the presence of a dopamine D1 receptor by rank order of various dopaminergic and nondopaminergic antagonists ((+)-SCH-23390 > (±)-SKF-83566 > (cis)-flupentixol > (+)-butaclamol > chlorpromazine > 1-sulpiride > mianserin > (−)-butaclamol). Stereoselectivity was evaluated by (+)- and (−)-butaclamol. The mean (± standard deviation) dissociation rate constant was 369 ± 196 pM with a density of 31.9 ± 12.5 fmol/mg membrane protein among 33 meningiomas.
The dopamine D2 receptor was not present in the 30 meningiomas examined for this. These findings indicate that the dopamine D1 receptor identified is expressed alone and is therefore regulated independent of a D2 receptor in cerebral meningioma tissue. Although the function of the dopamine D1 receptor in cerebral meningiomas has not so far been defined, previous studies have suggested that the D1 receptor might be involved in the control of proliferative growth of meningiomatous tissue.
Jürgen Honegger, Michael Buchfelder and Rudolf Fahlbusch
Object. This study aimed to elucidate the endocrinological outcome of craniopharyngioma surgery. In particular, endocrinological results were analyzed in relation to the surgical approach. The study includes 143 patients who underwent pre- and postoperative endocrinological assessment and who had not previously undergone surgery.
Methods. Diabetes insipidus was the most common postoperative deficiency in both the transcranial and transsphenoidal groups. The overall percentage of patients with diabetes insipidus increased from 16.1% preoperatively to 59.4% postoperatively. After transcranial surgery, the rate of anterior pituitary deficiency also increased. However, normal preoperative anterior pituitary function was maintained in more than 50% of patients for each endocrine axis. Similar results were attained in the group of patients undergoing complete tumor removal. The best result was achieved for gonadal function: the incidence of hypogonadism increased only slightly from 77.4 to 79.8%. The rate of anterior pituitary failure at presentation was much higher in the transsphenoidal than in the transcranial group. During transsphenoidal surgery, intact anterior pituitary functions were generally preserved. The rate of panhypopituitarism increased only slightly, from 40% before surgery to 42.9% after surgery. Endocrinological results were not inferior in patients with a ventrally displaced pituitary. This variant required midline incision of the gland for exposure of the craniopharyngioma. In the entire series of 143 patients the pituitary stalk was generally preserved. Postoperative panhypopituitarism was encountered in only one of eight patients in whom the pituitary stalk was partially resected because of tumor infiltration. None of the 88 patients who remained recurrence-free demonstrated endocrinological deterioration during follow-up review, compared with the early postoperative assessment 3 months postsurgery. On the other hand, complete recovery of one endocrine axis was observed in nine of these patients during later follow-up evaluations. In five of them, diabetes insipidus had regressed.
Conclusions. It is worth preserving the pituitary stalk and gland at surgery because of the definite chance that intact anterior pituitary functions can be maintained. Postoperative diabetes insipidus must be accepted as a common sequela following attempts at complete removal of the craniopharyngioma.