[Transcranial microsurgical decompression of the optic canal in surgical treatment of meningiomas of the sellar region]

RATIONALE

When removing the meningiomas of the sellar region, there is always a risk of visual impairment for various reasons, in particular, as a result of traction damage to the optic nerve. Decompression of the optic canal increases nerve mobility during tumor manipulation. In cases of meningioma growing into the canal, its decompression often seems necessary.

AIM

Evaluation of the effectiveness and risks of performing decompression of the optic canal.

MATERIALS AND METHODS

The study included patients with meningiomas of the parasellar location, who underwent surgical treatment at the Burdenko Neurosurgical Center for the period from 2001 to 2017. They were divided into two groups - main and control. The main group consisted of 129 patients who underwent decompression of the optic nerve canals when the tumor was removed. The tumor matrix in this group was most often located in the region of the tuberum sellae, supradiaphragmally, in the region of the anterior clinoid process and the optic canal. In 31 cases, decompression was bilateral - during one operation and using one access in 27 patients; in 4 cases, the decompression of the second canal was delayed for 1.5-3 months after the first operation. 160 decompressions were performed by the intradural and 7 - by extradural methods. During intradural decompression, the roof of the optic canal was resected, and during extradural decompression, the lateral wall of the canal was trephined. The control group consisted of 308 patients who did not undergo canal decompression when the tumor was removed. It included meningiomas with a predominant location of the matrix in the area of the tuberclum and diaphragm of the sella. Tumors in both groups were removed according to the same principles (matrix coagulation, mainly the gradual removal of the tumor, the use of ultrasonic aspirator, a situational decision on the radicality of the operation, etc.). The main difference between operations in these two groups was only canal related algorithms (with or without its trepanation), as well as the probable prevalence of significant lateral tumor growth in cases with canal trepanation. Visual functions in the «primary» group were evaluated before and after operations with trepanation of the canal depending on various factors - the initial state of vision and the radicality of the tumor excision, including removal from the canal. The differences in the postoperative dynamics of vision in the main and control groups were studied. The primary data processing was carried out using the program MSExcel. Secondary statistical processing was carried out using the program Statistica. To assess the statistical significance of differences in the results obtained in the compared patient groups, the Chi-square test was used, and in the case of small groups - the exact Fisher test was applied.

RESULTS

In the main group postoperative vision improvement of varying degrees on the side of trepanation was registered in 36.9% (59 out of 160) cases, no vision changes were found in 36.9% (59 out of 160), and in 26,2% (42 out of 160) the eyesight deteriorated. If preserving vision is attributed to a satisfactory result, then in general the results of these operations should be considered good. A comparative study of the results of removal of meningiomas with trepanation of the canals (main group) or without it (control group) was carried out among patients with the most critical vision situation (visual acuity 0.1 and below, up to only light perception). These groups are comparable in the number of observations - 62 and 73 respectively. The predominance of cases with improved vision in the main group compared with the control group (50.0% versus 38.36%) and a lower incidence of vision impairment (22.58% versus 34.25%) were found. However, the revealed differences are statistically unreliable and make it possible for us to talk only about the trend. The complications associated with trepanation of the canal include mechanical damage to the nerve by the drill. In our series of observations, there was only 1 case of abrasion of the nerve surface with the burr, which did not lead to a significant visual impairment. With the intradural method of trepanation in the area of the medial wall of the canal, the sphenoid sinus may open (in our series, in 34 cases out of 160 trepanations). Immediately closure of these defects was performed by various auto- and allomaterials in various combinations (pericranium, fascia, muscle fragment, hemostatic materials, and fibrin-thrombin glue). A true complication - CSF rhinorrhea liquorrhea developed in only one case, which required transnasal plastic surgery of the CSF fistula using a mucoperiostal flap.

CONCLUSIONS

1. Trepanation of the optic canal in cases of meningiomas of parasellar localization is a relatively safe procedure in the hands of a trained neurosurgeon and does not worsen the results of operations compared with the excision of the same tumors without trepanation of the canal. 2. The literature data and the results of our study make it possible to consider the decompression of the optic canal as an optional, but in many cases, useful option that facilitates the transcranial removal of some meningiomas of the sellar region.

[Primary sellar neuroblastoma (clinical case and literature review)]

Neuroblastoma is a malignancy developing from the embryonic neuroblasts of sympathetic nervous system. Primary sellar neuroblastomas are extremely rare (there are currently only 11 case reports in the literature). Possible development of neuroblastoma in sellar region expands differential diagnosis of local processes due to inclusion of neuroblastoma into the spectrum of suspected tumors. We report a literature review and description of a patient with primary sellar neuroblastoma.

[Transsphenoid extirpation of pituitary adenomas in patients with McCune-Albright syndrome (two cases from practice and literature review)]

INTRODUCTION

McCune-Albright Syndrome is a rare genetic disease characterized by the formation of fibrous osteodysplasia foci of various localization, including the bones of skull base. Having a gross lesion of the main bone body and the simultaneous formation of the pituitary adenoma, its transnasal removal becomes very difficult.

MATERIAL AND METHODS

Two clinical observations are presented where at patients with the classic manifestation of McCune-Albright syndrome we were able to successfully remove somatotropinomas with endoextrasellar growth. In both cases the presence of visual disorder was the indication for surgery.

RESULTS

Despite pronounced deviations in the anatomy of the skull base bones in both cases we managed to access the Turkish saddle. Removal of the pituitary tumor did not differ from standard surgery. Improved vision after surgery was observed in two patients. Tumors were removed subtotally and clinical and biochemical remission of acromegaly was not achieved. In both cases, the tumors had morphological signs of atypia. Patients continued to receive therapy with somatostatin analogues and radiation.

CONCLUSION

The possibility of performing transnasal surgery in this category of patients using specific instruments and intraoperative navigation is shown.

[Transsphenoidal surgery of suprasellar meningiomas - is there a future for the technique?]

Surgery of suprasellar meningiomas is a challenge and associated with a high risk of injury to the vascular-neural structures lying along the approach and surrounding the tumor. Currently, many foreign clinics and our Center have introduced a technique for resection of suprasellar meningiomas through the anterior extended transsphenoidal endoscopic endonasal approach.

OBJECTIVE

The study objective was to evaluate the role of extended transsphenoidal endoscopic endonasal approaches in surgery of suprasellar meningiomas.

MATERIAL AND METHODS

The present study is a retrospective analysis of surgical treatment outcomes in 45 patients (11 males and 34 females aged 23 to 70 years (median, 50 years) with suprasellar meningiomas who underwent surgery for skull base tumors using the anterior extended transsphenoidal endoscopic endonasal approach in the Surgery Department of the Burdenko Neurosurgical Institute in the period from 2009 to 2017. In all cases, surgery was the primary method of treatment.

RESULTS

Total tumor resection (the tumor was resected completely together with an infiltrated DM - Simpson 1) was achieved in 77.8% (35/45) of cases; subtotal resection (more than 80% of the tumor was removed) was in 17.8% (8/45) of cases; in 4.4% (2/45) of cases, resection was partial (less than 80% of the tumor was resected). Worsening or development of visual impairments immediately after surgery occurred in 13 (28%) of 45 patients. In 3 of them, vision was completely recovered on conservative treatment by the time of hospital discharge. In 4 patients, vision partially improved by the time of discharge. In 6 patients, vision was not recovered by discharge (in 2 of them, vision partially improved during follow-up). Therefore, by the time of hospital discharge, deterioration in vision occurred in 10 (22%) of 45 patients. In 7 (21.2%) out of 33 patients who had visual impairments before surgery, there was an improvement in vision in the postoperative period.

CONCLUSION

Analyzing the findings and generalizing our experience, we may say that, in surgery of suprasellar meningiomas, the anterior extended transsphenoidal endoscopic endonasal approach should be used for relatively small (up to 3 cm), medially located symmetrical tumors that do not involve large vessels. The efficacy of this technique for tumors extending into the optic nerve canals requires additional analysis in a larger series of cases.

[The use of platelet gel for repair of a cerebrospinal fluid fistula of the skull base (a case report and literature review)]

Nasal liquorrhea is a serious problem in surgery of skull base tumors, which is associated with a high risk of purulent-septic complications. This paper presents a case of successful repair of a cerebrospinal fluid fistula with an autologous platelet gel in the postoperative period after removal of meningioma of the anterior cranial fossa base, which was accompanied by a purulent-inflammatory complication in the surgical wound area.

[Cerebrospinal fluid rhinorrhea in primary treatment of large and giant prolactinomas with dopamine agonists]

At present, pharmacological therapy of prolactinomas with dopamine agonists (DAs) is considered the treatment of choice. In most cases, giant prolactinomas respond to treatment with dopamine agonists and decrease in size during the first months of the treatment. One of the rare but dangerous complications of conservative treatment of prolactinomas with invasive growth is cerebrospinal fluid rhinorrhea.

MATERIAL AND METHODS

We present a retrospective analysis of 15 patients with macropropactinomas who underwent surgery for cerebrospinal fluid rhinorrhea developed due to primary therapy with dopamine agonists at the Burdenko Neurosurgical Institute (BNI) in the period between 2005 and 2015. All patients had large and giant tumors (according to the classification adopted at the BNI). When cerebrospinal fluid rhinorrhea was detected, patients were hospitalized to the BNI for examination, detection of a CSF fistula, reconstruction of a defect, and resection (if possible) of the tumor.

RESULTS

In the period between 2005 and 2015, 15 patients (8 males and 7 females) with prolactinomas of a large and giant size at the onset of conservative therapy underwent surgery for cerebrospinal fluid rhinorrhea at the BNI. All patients underwent transnasal reconstruction of a skull base defect, with 13 out of 15 patients undergoing simultaneous resection of the tumor. After tumor resection, reconstruction was performed using auto-fat, fascia, and glue (in 8 cases). In the remaining cases, apart from auto-fat, fascia, and glue, a mucoperiosteal flap and auto-bone were used. Fourteen patients were followe-up. In 13 cases, there was no relapse of cerebrospinal fluid rhinorrhea after skull base reconstruction. In 1 case, there was a relapse of cerebrospinal fluid rhinorrhea.

CONCLUSION

Conservative treatment of patients with giant prolactinomas should be performed under regular control of ENT doctors and neurosurgeons for timely detection and surgical treatment of cerebrospinal fluid rhinorrhea.

[The extended endoscopic endonasal transsphenoidal approach in surgery for epidermoid cysts of the chiasmatic region]

Surgical treatment for epidermoid cysts of the chiasmatic region is a challenge because of the tendency to a massive spread of epidermoid masses through the cerebrospinal fluid pathways and a significant lesion deviation from the midline.

PURPOSE

To analyze capabilities of the extended endoscopic endonasal transsphenoidal approach in surgery for epidermoid cysts.

MATERIAL AND METHODS

The study included 6 patients with epidermoid cysts of the chiasmatic region who were operated on using the extended anterior endoscopic endonasal transsphenoidal approach at the Burdenko Neurosurgical Institute in the past 5 years.

RESULTS

Epidermoid masses were completely removed in 5 patients; in none of the cases, complete removal of the epidermoid cyst capsule was achieved. There were no cases of vision deterioration and the development of new focal neurological symptoms. One female patient developed hypopituitary disorders in the postoperative period. There was no recurrence of epidermoid cysts during follow-up.

CONCLUSION

Removal of epidermoid cysts of the chiasmatic region using the extended anterior endoscopic transsphenoidal approach may be an alternative to transcranial microsurgery.

[Clinical and morphological characteristics, diagnostic criteria, and outcomes of surgical treatment of TSH-secreting pituitary adenomas]

Thyrotropinomas (TSH-secreting tumors) are a rare type of pituitary adenomas, which account for about 0.5-2.0% of all pituitary tumors. The criterion of thyrotropinoma is visualization of the tumor in the presence of a normal or elevated level of the thyroid-stimulating hormone (TSH) in the blood and elevated concentrations of free T4 (fT4) and free T3 (fT3).

OBJECTIVE

To study the clinical, diagnostic, and morphological characteristics and treatment outcomes of TSH-secreting pituitary tumors.

MATERIAL AND METHODS

The study included 21 patients aged from 15 to 67 years with pituitary adenoma and a normal or elevated blood TSH level combined with elevated fT4 and fT3 levels who were operated on at the Neurosurgical Institute in the period between 2002 and 2015. Before surgery, in the early postoperative period, and 6 months after surgery, the patients were tested for levels of TSH, fT4, fT3, prolactin, cortisol, the luteinizing hormone (LH), the follicle-stimulating hormone (FSH), estradiol/testosterone, and the insulin-like growth factor (IGF-1). The thyroid status was evaluated using the following reference values: TSH, 0.4-4.0 mIU/L; fT4, 11.5-22.7 pmol/L; fT3, 3.5-6.5 pmol/L. An immunohistochemical study of material was performed with antibodies to TSH, PRL, GH, ACTH, LH, FSH, and Ki-67 (MiB-1 clone); in 13 cases, we used tests with antibodies to somatostatin receptors type 2 and 5 and to D2 subtype dopamine receptors.

RESULTS

Thyrotropinomas were detected in patients aged from 15 to 67 years (median, 39 years), with an equal rate in males (48%) and females (52%). Before admission to the Neurosurgical Institute, 11 (52%) patients were erroneously diagnosed with primary hyperthyroidism; based on the diagnosis, 7 of these patients underwent surgery on the thyroid gland and/or received thyrostatics (4 cases). Hyperthyroidism symptoms were observed in 16 (76%) patients. The blood level of TSH was 2.47-38.4 mIU/L (median, 6.56); fT4, 22.8-54.8 nmol/L (median, 36); fT3, 4.24-12.9 pmol/L (median, 9.66). Tumors had the endosellar localization in 4 (19%) cases and the endo-extrasellar localization in 17 (91%) cases. Total tumor resection was performed in 7 (33%) patients. All these tumors had the endosellar and endo-suprasellar localization. No total resection was performed in patients with infiltrative growth of adenoma (invading the skull base structures). An immunohistochemical study of tumor resection specimens detected only TSH expression in 3 (14%) cases; 18 (86%) tumors were plurihormonal and secreted TSH and GH and/or PRL. Of 13 tumors, expression of the type 2 dopamine receptor was detected in 9 (69%) cases; expression of somatostatin receptors type 5 and type 2 was found in 6 (46%) and 2 (15%) cases, respectively.

CONCLUSION

The criterion for total tumor resection was a postoperative decrease in the TSH level to 0.1 mIU/L or less. Total resection was performed in 33% of patients with tumors of only the endosellar and endo-suprasellar localization. In most cases, tumors were plurihormonal and secreted TSH and GH and/or PRL.

[Endoscopic transsphenoidal resection of pituitary adenomas invading the cavernous sinus]

INTRODUCTION

Pituitary adenomas are benign growths that invade the cavernous sinus (CS) in 10-15% of cases. There are different types of microsurgical and endoscopic approaches enabling resection of tumors from the CS cavity that is a relatively small and hard to reach anatomical structure comprising eloquent neurovascular structures.

MATERIAL AND METHODS

A study group included 97 patients with pituitary adenomas (PAs) invading the CS. PAs were resected using an endoscopic technique: adenomas were resected from the CS cavity through a standard endoscopic endonasal transsphenoidal approach in 62 cases; a lateral extended transsphenoidal endoscopic approach was used in 35 cases. A control group included patients with PAs spreading into the laterosellar region who were operated on using microsurgical extra-intradural (n=14) and transsphenoidal (n=149) approaches. In the study group, the degree of PA invasion into the CS cavity was determined using the Knosp scale.

RESULTS

In the study group, total tumor resection was achieved in 49 (50.5%) cases, subtotal resection in 39 (40.2%) cases, and partial resection in 9 (9.3%) patients. In the case of visual disorders (n=70), vision improvement was achieved in 41.4% of cases. Vision deterioration was detected in 11.4% of cases; no vision changes were in 47.1% of cases. Patients (27.8%) who had not had visual impairments before surgery had no negative changes in vision in the postoperative period. The development/augmentation of oculomotor disorders in the study group occurred in 14 (14.4%) cases. In the study group, hormonal remission of the disease in patients with hormone-active PAs was in 26.7% of cases (n=12). There were no cases of nasal liquorrhea, meningitis, and death in the study group.

CONCLUSION

Endoscopic endonasal transsphenoidal resection of PAs invading the CS is a more efficient and safer surgical technique compared to microsurgical techniques (transsphenoidal and extra-intradural approach). The lateral extended transsphenoidal endoscopic approach enables resection of PAs with massive invasion into the CS (Grade III and Grade IV, Knosp scale) and has less postoperative complications compared to the extra-intradural approach (p<0.05).

[Extended endoscopic endonasal posterior (transclival) approach to tumors of the clival region and ventral posterior cranial fossa. Part 1. Topographic and anatomical features of the clivus and adjacent structures]

OBJECTIVE

to describe the main topographic and anatomical features of the clival region and its adjacent structures for improvement and optimization of the extended endoscopic endonasal posterior (transclival) approach for resection of tumors of the clival region and ventral posterior cranial fossa.

MATERIAL AND METHODS

We performed a craniometric study of 125 human skulls and a topographic anatomical study of heads of 25 cadavers, the arterial and venous bed of which was stained with colored silicone (the staining technique was developed by the authors) to visualize bed features and individual variability. Currently, we have clinical material from more than 120 surgical patients with various skull base tumors of the clival region and ventral posterior cranial fossa (chordomas, pituitary adenomas, meningiomas, cholesteatomas, etc.) who were operated on using the endoscopic transclival approach.

RESULTS

We present the main anatomical landmarks and parameters of some anatomical structures that are required for performing the endoscopic endonasal posterior approach. The anatomical landmarks, such as the intradural openings of the abducens and glossopharyngeal nerves, may be used to arbitrarily divide the clival region into the superior, middle, and inferior thirds. The anatomical landmarks important for the surgeon, which are detected during a topographic anatomical study of the skull base, facilitate identification of the boundaries between the different clival portions and the C1 segments of the internal carotid arteries. The superior, middle, and inferior transclival approaches provide an access to the ventral surface of the upper, middle, and lower neurovascular complexes in the posterior cranial fossa.

CONCLUSION

The endoscopic transclival approach may be used to access midline tumors of the posterior cranial fossa. The approach is an alternative to transcranial approaches in surgical treatment of clival region lesions. This approach provides results comparable (and sometimes better) to those of the transcranial and transfacial approaches.

[Application of intraoperative electromagnetic frameless navigation in transcranial and endoscopic neurosurgical interventions]

The paper summarizes the experience in using a system of electromagnetic intraoperative frameless navigation in various neurosurgical pathologies of the brain. The electromagnetic navigation technique was used for 102 operations in 98 patients, including 36 transnasal endoscopic interventions. There were no intraoprtative and postoperative complications associated with the use of the system. In the process of using the system, factors influencing the accuracy of navigation and requiring additional control by the surgeon were identified.

PURPOSE

The study purpose was to evaluate the use of electromagnetic navigation in surgical treatment of patients with various brain lesions.

MATERIAL AND METHODS

The system of electromagnetic navigation was used for 102 operations in 98 patients (42 males and 56 females, including 18 children; median age, 34.8 years (min, 2.2 years; max, 69 years)) in the period from December 2012 to December 2016. In 36 patients, the system was used for endoscopic interventions. In 19 patients, electromagnetic navigation was used in combination with neurophysiological monitoring.

RESULTS

In our series of cases, the frameless electromagnetic navigation system was used in 66 transcranial operations. The mean error of navigation was 1.9±0.5 mm. In 5 cases, we used the data of preoperative functional MRI (fMRI) and tractography for navigation. At the same time, in all 7 operations with simultaneous direct stimulation of the cortex, there was interference and significant high-frequency noise, which distorted the electrophysiological data. A navigation error of more than 3 mm was associated with the use of neuroimaging data with an increment of more than 3 mm, image artifacts from the head locks, high rate of patient registration, inconsequence of touching points on the patient's head, and unsatisfactory fixation to the skin or subsequent displacement of a non-invasive localizer of the patient. In none of the cases, there was a significant effect of standard metal surgical tools (clamps, tweezers, aspirators) located near the patient's head on the navigation system. In two cases, the use of massive retractors located near the patient's localizer caused noise in the localizer and navigation errors of more than 10 mm due to significant distortions of the electromagnetic field. Thirty-six transnasal endoscopic interventions were performed using the electromagnetic frameless navigation system. The mean navigation error was 2.5±0.8 mm.

CONCLUSION

In general, electromagnetic navigation is an accurate, safe, and effective technique that can be used in surgical treatment of patients with various brain lesions. The mean navigation error in our series of cases was 1.9±0.5 mm for transcranial surgery and 2.5±0.8 mm for endoscopic surgery. Electromagnetic navigation can be used for different, both transcranial and endoscopic, neurosurgical interventions. Electromagnetic navigation is most convenient for interventions that do not require fixation of the patient's head, in particular for CSF shunting procedures, drainage of various space-occupying lesions (cysts, hematomas, and abscesses), and optimization of the size and selection of options for craniotomy. In repeated interventions, disruption of the normal anatomical relationships and landmarks necessitates application of neuronavigation systems in almost mandatory manner. The use of electromagnetic navigation does not limit application of the entire range of necessary intraoperative neurophysiological examinations at appropriate surgical stages. Succession in application of neuronavigation should be used to get adequate test results.

The use of intraoperative Doppler ultrasound in endoscopic transsphenoidal surgery

INTRODUCTION

Doppler ultrasound (DUS) has been widely used in neurosurgical practice to diagnose various cerebrovascular diseases. This technique is used in transsphenoidal surgery to identify the localization of intracranial arteries when making an approach or during tumor resection.

MATERIAL AND METHODS

To identify the cavernous segment of the internal carotid artery (ICA) and/or basilar artery during endoscopic transsphenoidal surgery, we used a combined device on the basis of a click line curette («Karl Storz») and a 16 MHz Doppler probe (Lassamed). The technique was used in 51 patients during both standard transsphenoidal surgery (23 cases) and transsphenoidal tumor resection through an extended approach (28 cases).

RESULTS AND DISCUSSION

Doppler ultrasound was used in different situations: to determine a trajectory of the endonasal transsphenoidal approach in the absence of the normal anatomical landmarks (16 cases), to define the limits of safe resection of a tumor located in the laterosellar region (7), and to implement an extended transsphenoidal endoscopic approach (28). Intraoperative Doppler ultrasound enabled identification of the cavernous segment of the internal carotid artery in 45 cases and the basilar artery in 2 cases; a blood vessel was not found in 4 cases. Injury to the cavernous segment of the internal carotid artery was observed only in 1 case.

CONCLUSION

The use of the described combined device in transsphenoidal surgery turned Doppler ultrasound into an important and useful technique for visualization of the ICA within the tumor stroma as well as in the case of the changed skull base anatomy. Its use facilitates manipulations in a deep and narrow wound and enables inspection of the entire surface of the operative field in various planes, thereby surgery becomes safer due to the possibility of maximum investigation of the operative field.

[SCT perfusion in the diagnosis of sellar and parasellar tumors]

The study is devoted to the use of a minimally invasive method of SCT perfusion for the differential diagnosis of sellar and pаrаsellar tumors. Given a wide differential diagnostic range of tumors occurring in this area, the tumor perfusion indicators were used as an auxiliary diagnostic criterion.

MATERIAL AND METHODS

The study analyzed outcomes in 115 patients with various tumors of the sellar area who underwent surgery or biopsy for histological verification of the diagnosis.

RESULTS

The statistically significant differences were obtained for certain groups of tumors based on the values of hemodynamic parameters (p<0.05) that enable, with a high confidence, making a conclusion on the histologic type of most tumors.

CONCLUSION

These findings demonstrated that SCT perfusion is a highly informative method of the preoperative differential diagnosis of these tumors. The sensitivity and specificity of SCT perfusion in the study were 100% and 81.2%, respectively.

[The effectiveness of using HyperHAES hypertonic isooncotic plasma solution to achieve stable intracranial hypotension in endoscopic endonasal transsphenoidal adenomectomy as an alternative to the invasive external lumbar drainage]

The structure of surgery of pituitary adenomas has been fundamentally changed over the past decade. The transnasal transsphenoidal approach is currently used to resect more than 95% of adenomas. The wide use of endoscopy has changed the need for perioperative control of intracranial pressure. While controlled intracranial hypertension was previously used during microscopically controlled transnasal surgery to bring the suprasellar capsule and tumor remnants to the field of vision, endoscopically controlled tumor resection implies that controlled intracranial hypotension is required to achieve complete spreading of the suprasellar capsule. External lumbar drains inserted at least for the entire surgery duration are conventionally used to control intracranial pressure. We present the results of the study proving the effectiveness and safety of the HyperHAES hypertonic isooncotic plasma substitute in achieving stable intracranial hypotension according to a large body of clinical data. Our findings give grounds for claiming that the use of the HyperHAES hypertonic isooncotic plasma substitute during the standard adenomectomy allows one to abandon the use of invasive external lumbar drainage, while the surgery quality and risks remain at the same level.

Experience of surgical management of trigeminal schwannomas that simultaneously spread to the middle and posterior cranial fossae

INTRODUCTION

trigeminal schwannomas account for 0.07-0.36% of all intracranial tumors and 0.8-8% of all intracranial schwannomas. Different surgical approaches are used depending on the topographic anatomical variant of the tumor. Dumbbell-shaped tumors that spread both to the middle and posterior cranial fossae are the most challenging ones in terms of their resection.

MATERIAL AND METHODS

Five patients with dumbbell-shaped trigeminal schwannomas were operated on at the Burdenko Neurosurgical Institute in 2011-2013. In four cases, tumor resection comprised two stages using the retrosigmoid suboccipital approach (RSA) and lateral extended transsphenoidal endoscopic approach (LETEA); in one case, the tumor was resected in a single session through the LETEA. If there were pronounced symptoms affecting the brainstem and/or cerebellum, tumor resection from the posterior cranial fossa through RSA was resected at the first stage (3 cases). If no symptoms were observed, tumor resection from the middle cranial fossa through LETEA was used as the first stage (2 cases).

RESULTS

After two surgical stages, total, subtotal, and partial tumor resection was performed (one case each). Total tumor resection from the middle cranial fossa was achieved through LETEA in two cases. Aggravation of ipsilateral paresis of the craniocerebral nerve VI was observed after the surgery in two cases. No cases of nasal liquorrhea were observed after transnasal surgery. In one case, the cavernous segment of the internal carotid artery was damaged during LETEA, thus requiring endovascular occlusion of the damaged vessel to be performed.

CONCLUSION

LETEA is an effective approach that allows resection of tumors from the middle cranial fossa and the cavernous sinus. Combined with RSA, this approach can be used for two-stage resection of dumbbell-shaped trigeminal schwannomas.

Assessment of optic nerve decompression efficiency in resection of sellar region meningiomas via intradural subfrontal approach

In this article we analyze results of the different variants of the optic nerve transcranial decompression in cases with different chiasmal region tumors. We operate 70 patient with different type meningioma (tuberculum sella, shenoid wings, anterior clinoid, optic canal), pituitary adenoma and one case with tuberculoma (we operate it thinking on meningioma, but histology was unexpected). Groups of the patients. Group1. 20 patients with pituitary adenoma with cavernous sinus invasion. It was our "pre-endoscopic" period when we frequently operated adenomas by transcranial approach. In this 20 patients we used intra-extradural Dolenc approach to cavernous sinus. In that cases we removed anterior clinoid process and decompressed optic canal. Here we use the results of surgery in this group for showing the possibility of using high speed drill for the optic canal decompression - for showing it safety. On our opinion this type of optic canal decompression is radical and safe but superfluous for the optic canal invasion by the meningioma. Group 2. 19 patients with meningioma. In that cases we partially unroofed optic canal by Kerrison and additionally we cut the falciform ligament. Group 3. 31 patients with meningioma. It's our "main" group. Here we made intradural wide unroofing the optic canal by high speed drill. Additionaly we cut the falciform ligament and open the dural sheet of the optic nerve. We propose this methodic like sufficient, safe and useful. In this cases we frequently saw the tumor spread inside the dural sheet of the optic nerve, without seeing it on the MRI. A lot of cases in this group was a recurrent after previous meningioma removal. Like a control groups we use two. Group 4. 11 cases with meningioma. In that cases we removed tumor from optic canal without any decompression. It was our archive group - we made this type of surgery before starting optic canal decompression. This group shows the risks of any manipulation with fixed optic nerves without optic canal decompression. Group 5. 31 case with meningioma. In this cases we saw the optic canal invasion by the tumor but we didn't try to decompress it. It was our archive group - we made this type of surgery before starting optic canal decompression. We use this group for found out the risks of canal decompression. This group shows the poor perspectives for the vision in optic canal invasion by the tumor without it decompression. We analyze the results of surgery on the day of discharge and on catamnesis - we decide that the optic nerves need time to recovery. We analyzed the results of surgery in patients with 3 types of the visual dysfunction: moderate (1.0-0.5), hard (0.5-0.1), decompensating (0.1-0). For showing the real risks and effectivety of any type of decompression and surgery without decompression we look for results in patients with decompensating of visual functions. For statistical analyses we use Fisher criteria which used in small series. We statistically showed that any attempts of tumor removal form the optic canal is more risky than decompression. Also we found a tendency that wide intradural decompresstion made by high speed drill with additional falciform ligament cutting and the dural sheet opening is more effective and safe than opening the optic canal by Kerrisson. This technique also could be used during the transcranial surgery for the other type of pathology particularly in cases with short optic nerves and prefixed chiasm - it gives the mobility for the nervesand decreased the nerve damaging.

Transsphenoidal surgery of craniopharyngioma: form palliative surgery to radical removal

The paper presents basic principles of transsphenoidal craniopharyngioma surgery. Stages of methodology development. Steps of methodology development of such operations in the Institute are described--from palliative interventions to the high-tech modern radical surgery with the use of anterior extended approach. Additional stereotactic irradiation provides reliable control of the disease for a long period. The article mainly describes operative technique and contains preliminary analysis of the surgical results showing effectiveness and safety of endoscopic removal of craniopharyngioma.

Endoscopic endonasal anterior extended transsphenoidal approach in craniopharyngioma surgery

The paper describes results of treatment of 56 patients with suprasellar craniopharyngioma (stem, intra-extraventricular) who were operated in Burdenko Neurosurgical Institute using endoscopic endonasal anterior extended transsphenoidal approach. Assessed dynamics of major clinical syndromes (neuro-ophthalmological symptoms, neurological and hormonal status), radicality of surgery, incidence and nature of postoperative complications, postoperative mortality. A comparative analysis of the results obtained in previous studies of our Institute, as well as with those of foreign authors is performed. Obtained data show that endoscopic endonasal anterior extended transsphenoidal approach in craniopharyngioma surgery is an efficient and non-traumatic technique, capable of providing a radical removal of the tumor along with a high quality of life after surgery, and relatively low rates of postoperative complications and mortality.

Damage to the cavernous segment of internal carotid artery in transsphenoidal endoscopic removal of pituitary adenomas (report of 4 cases)

Endoscopic endonasal transsphenoidal approach (EETA) is an effective and relatively safe to remove pituitary adenomas and other sellar region tumors. One of the most serious complications of transsphenoidal surgery is damage to the cavernous segment of the internal carotid artery, which by different authors occurs at 0 to 3.8%. In the period from 2005 to March 2013 in Burdenko neurosurgical institute 3,000 patients with pituitary adenomas were operated by standard endoscopic transsphenoidal approach. Damage to the internal carotid artery (ICA) occurred in 4 patients, which amounted to 0.13%. To all patients with damage of the ICA angiography was performed in which identified one case of occlusion of the ICA and three cases of false aneurysm formation. Three patients underwent endovascular treatment. Damage to the internal carotid artery may be associated with the wrong orientation in the surgical wound, or excessively aggressive manipulations in the cavernous sinus. Damage to the cavernous segment of the ICA during transsphenoidal surgery is a rare but potentially fatal complication. Extremely important is the correct localization of the middle line and ICA using navigation systems and Doppler ultrasound.

[Experience of skull base defect reconstruction using local pedicled grafts in endoscopic transsphenoidal surgery]

Since endoscopic technique was introduced in transsphenoidal surgery, the midline skull base from olfactory fossa to craniocervical junction has become available through transnasal corridor. One of the most challenging aspects in these types of surgery is watertight closure of skull base defect and prevention of postoperative CSF leaks. Various materials and sealants are applied in different clinics. Recently mucoperiosteal flap from nasal septum was introduced as "gold standard" for multilayer skull base reconstruction. We present our algorithm for selection of skull base reconstruction technique in endoscopic endonasal surgery. We demonstrate our experience of using of pedicled autografts (middle turbinate and mucoperiosteal flap). Surgical technique of grafting is described in details. Clinical results in 41 surgically treated patients are presented. First results of using of pedicled autografts demonstrated high effectiveness of this technique with acceptable rates of nasal complications in comparison to standard methods.

[Endoscopic endonasal surgery of pituitary adenomas (experience of 1700 operations)]

The current paper analyses results of endoscopic endonasal surgical treatment of 1700 patients with pituitary adenomas in Burdenko Neurosurgical Institute during recent 7 years. We assessed the following parameters: dynamics of basic syndromes (neuroophthalmological, neurological and endocrinological symptoms), degree of resection, frequency and types of postoperative complications, postoperative mortality, recurrence rate etc. The obtained data were compared with results of microsurgical transnasal operations which were formerly performed in our department, as well as with results of leading endoscopic neurosurgeons of the world. In majority of parameters our results are on the same level as the data of most prominent endoscopic neurosurgeons of the world and are significantly better that in the group of patients operated using a microscope.

[Comparative analysis of surgical and medical treatment of macroprolactinoma of different localization]

The authors performed comparative analysis of results of primary surgical and medical treatment of 306 patients with macroprolactinoma. The series included 178 male and 128 female patients. The tumor was endosellar in 48 cases, endosuprasellar in 94, invaded skull base in 164. The paper demonstrates that according to dynamics of visual function, neurological and hypopituitary symptoms, and probability of prolactin level normalization, treatment with cabergoline has significant advantages in comparison to surgery. Only surgical treatment of endosellar prolactinomas can compete with conservative treatment. After these operations no postoperative complications were observed, normalization of prolactin level was present in 67% of cases, and these results did not differ from results of medical treatment (71%). In case of extrasellar grown of macroprolactinoma, especially invading skull base, primary medical therapy is preferred.

[Changes in visual and oculomotor impairments after endoscopic endonasal transsphenoidal removal of pituitary adenomas]

Changes in visual functions were analyzed in 427 patients with pituitary adenomas after endoscopic endonasal transsphenoidal tumor removal. The analysis indicated that not only the specific features of tumor growth and size and the baseline function, but also the efficacy of surgery and a patient's age affect postoperative changes in visual impairments. Endoscopic endonasal transsphenoidal adenomectomy was found to result in no clinical improvement as compared with the earlier used procedures of microscopic transnasal removal with and without an endoscope additionally used at some surgical stages.

[Surgical treatment for giant pituitary adenomas: the state of visual functions]

Giant pituitary adenomas (more than 60 mm) are a most difficult group of tumors of the pituitary. Surgery is practically the only treatment, visual functions being most vulnerable. The study showed that the procedures for removal of tumors through transsphenoidal approach (improved vision or no negative changes was noted in 78.2% of the patients) or made in 2 steps (a good result was obtained in 64.7%) presented the least risk. The most complete removal of a supracellular tumor portion irrespective of a chosen approach yields a better result than non-radical operations despite its potentially high traumaticity of visual nerves and optic chiasms.

[Surgical treatment of pituitary adenomas using endoscopic endonasal trans-sphenoidal approach]

A new method for the removal of chiasma-sellar tumours is proposed consisting of endoscopic endonasal trans-sphenoidal surgery is described. A total of 400 operations were made with the use of this technique. Analysis of their results revealed merits and demerits of the endoscopic endonasal trans-sphenoidal approach. Practical aspects of the endoscopic procedure are discussed and recommendations on its introduction into routine clinical work proposed.

[Extended endoscopic endonasal transsphenoidal approaches in skull base surgery]

The article deals with endoscopic endonasal transsphenoidal surgery, which has gained great interest among the modem trends of neurosurgery. Application of extended endoscopic endonasal transsphenoidal approaches significantly advances capabilities of transsphenoidal surgery. Pituitary adenomas and some other sellar tumors which traditionally require transcranial procedure now can be removed via endonasal route. The article describes several types of extended endoscopic endonasal transsphenoidal approaches.

[Clinical presentation, diagnostics and results of primary conservative treatment of large and giant prolactin-secreting pituitary adenomas]

A prospective study of 55 patients with large and giant prolactin-secreting pituitary tumors receiving dopamine agonists as primary treatment was performed. Statistically significant data were obtained indicating decrease of prolactin level, improvement of vision, normalization of sexual function and shrinking of the tumor. Effectiveness and safety of dopamine agonists in patients with large and giant prolactinomas are proved. Also we discovered possibility of nasal CSF leak during conservative treatment.

[Methods of the endoscopic endonasal transsphenoidal adenomectomy]

This paper provides the practical part of a procedure for endoscopic endonasal transsphenoidal resection of pituitary tumors. The authors have presently gained experience with about 400 endoscopic endonasal transsphenoidal operations. The advantages of endoscopic surgery include the wide vision field of an operative site under good illumination. The endoscopic intervention provides a possibility of extracting not only endo-, but also paracellular portions of a tumor under direct visual control, which can be rarely done during a standard microscopic transnasal operation. The paper gives recommendations on the equipment of an operating suite and anesthetic maintenance. It also describes surgical stages and postoperative management of patients.

[Rhinological aspects of endoscopic endonasal removal of hypophysial adenomas]

The authors analyse rhinological aspects of endoscopic endonasal transsphenoidal adenomectomy (EETA): a nasal operation, intra- and postoperative liquorrhea, liquorrhea-associated meningitis, postoperative nasal hemorrhage, local changes of nasal cavity anatomic structures; provide practical recommendations on management of the conditions many of which are life-threatening.

[Basilar skull fractures: clinical and prognostic aspects]

The incidence of basilar skull fractures and their clinical and prognostic aspects were studied in victims with varying severity of brain injury. Of 947 cases, 449 (46%) patients were diagnosed as having basilar skull fracture and 181 (18.6%) had basal spinal fluid leakage. The frequency of fractures and basal spinal fluid leakage increased in proportion to the severity of brain injury. The above 14-day history of spinal fluid leakage was an absolute indication for surgical fistula closure.