Outcome Squares Integrating Efficacy and Safety, as Applied to Functioning Pituitary Adenoma Surgery.

CONTEXT: Transsphenoidal surgery is standard care in the treatment of hormone-secreting pituitary adenomas. Current clinician-reported surgical outcome measures are one-dimensional, typically focusing primarily on complete or partial resection, and secondarily on complication rates. However, outcomes are best reflected by the delicate balance of efficacy and complications at patient level. OBJECTIVE: This study proposes a novel way to classify and report outcomes, integrating efficacy and safety at the patient level. METHODS: Retrospective chart review of all pure endoscopic transsphenoidal surgical procedures for acromegaly, Cushing's disease, and prolactinoma between 2010 and 2018 in a single tertiary referral center. We present our results in a classic (remission and complications separate) and in a novel outcome square integrating both outcomes, focusing on intended and adverse effects (long-term complications). This resulted in 4 outcome groups, ranging from good to poor. We use this approach to present these outcomes for several subgroups. RESULTS: A total of 198 surgical procedures were included (44 reoperations). Remission was achieved in 127 operations (64%). Good outcome was observed after 121 (61%), and poor outcome after 6 (3%) operations. When intended effect of surgery was applied (instead of remission), good outcome as intended was achieved after 148 of 198 surgeries (75%) and poor outcome after 4 (2%). CONCLUSION: Quality of a surgical intervention can be presented in 4 simple categories, integrating both efficacy and safety with flexibility to adapt to the individualized situation at patient, disease, and surgical strategy and to the outcome of interest.

Optic pathway tumor in children: Toward a new classification for neurosurgical use.

OBJECT: Optic pathway tumors (OPT) represent a challenge for pediatric neurosurgeons. Role of surgery is debated due to the high risk of iatrogenic damage, and in lasts decades it lost its importance in favor of chemotherapy. However, in some cases surgery is necessary to make biomolecular and histological diagnosis, to manage intracranial hypertension (IH) and to cooperate with medical therapies in controlling tumor relapse. With the aim to standardize selection of surgical OPT cases, we propose a simple, practical and reproducible classification. METHODS: We retrospectively analyzed data of 38 patients with OPT treated at our institution (1990-2018). After careful analysis of MRI images, we describe a new classification system. Group 1: lesion limited to one or both optic nerve(s). Group 2: chiasmatic lesions extending minimally to hypothalamus. Group 3: hypothalamo-chiasmatic exophitic lesions invading the third ventricle; they can be further divided on the base of concomitant hydrocephalus. Group 4: hypothalamo-chiasmatic lesions extending widely in lateral direction, toward the temporal or the frontal lobes. Patients' data and adopted treatment are reported and analyzed, also depending on this classification. RESULTS: Twenty children were operated on for treatment of OPT during the study period. Permanent clinical impairment was noted in 5 (25%) of operated patients, while visual improvement was noted in 1 patient. OS rate was 100% at 5 years, with a median follow up of 9 years (ranging from 2 to 23). Prevalence of intracranial hypertension and proportion of first-line surgical treatment decision were significantly higher in groups 3-4 compared to groups 1-2 (P<0.001 for both tests). CONCLUSION: Surgery can offer a valuable therapeutic complement for OPT without major risk of iatrogenic damage. Surgery is indispensable in cases presenting with IH, as in groups 3 and 4 lesions. Eligibility of patients to surgery can be based on this new classification system.

A systematic review and meta-analysis of supratotal versus gross total resection for glioblastoma.

PURPOSE: Due to the infiltrative nature of glioblastoma (GBM) outside of the contrast-enhancing region on MRI, there is interest in exploring supratotal resections (SpTR) that extend beyond the contrast-enhancing portion of the tumor. However, there is currently no consensus on the potential survival benefit of SpTR in GBM compared to gross total resection (GTR). In this study, we compare the impact of SpTR versus GTR on overall survival (OS) of GBM patients. METHODS: We performed a systematic review and meta-analysis of literature published on PubMed, Embase, The Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov, from inception to August 16, 2018, to identify articles comparing OS after SpTR versus GTR. RESULTS: We identified 8902 unique citations, of which 11 articles met study inclusion criteria. 810 patients underwent SpTR out of a total of 2056 patients. 9 of 11 studies demonstrated improved outcomes with SpTR compared to GTR (median improvement in OS of 10.5 months), with no significant difference in postoperative complication rate. Overall study quality was variable, with ten studies presenting level IV evidence and one study presenting level IIIb evidence. Subgroup meta-analysis based on SpTR definition demonstrated a statistically significant 35% lower risk of mortality in patients who underwent anatomical SpTR compared to patients who underwent GTR (Hazard ratio = 0.65, 95% CI 0.47- 0.91, p = 0.003). CONCLUSION: Our systematic review indicates SpTR may be associated with improved OS compared to GTR for GBM, especially with anatomical SpTR. However, this is limited by variable study design and significant clinical and methodological heterogeneity among studies. There is need for prospective clinical data to further guide parameters regarding the use of SpTR in GBM.

Modern radiosurgical and endovascular classification schemes for brain arteriovenous malformations.

Stereotactic radiosurgery (SRS) and endovascular techniques are commonly used for treating brain arteriovenous malformations (bAVMs). They are usually used as ancillary techniques to microsurgery but may also be used as solitary treatment options. Careful patient selection requires a clear estimate of the treatment efficacy and complication rates for the individual patient. As such, classification schemes are an essential part of patient selection paradigm for each treatment modality. While the Spetzler-Martin grading system and its subsequent modifications are commonly used for microsurgical outcome prediction for bAVMs, the same system(s) may not be easily applicable to SRS and endovascular therapy. Several radiosurgical- and endovascular-based grading scales have been proposed for bAVMs. However, a comprehensive review of these systems including a discussion on their relative advantages and disadvantages is missing. This paper is dedicated to modern classification schemes designed for SRS and endovascular techniques.

Surgery for temporal glioblastoma: lobectomy outranks oncosurgical-based gross-total resection.

OBJECTIVE: Supra-total glioblastoma resection has gained growing attention with regard to superior long-term disease control. However, aggressive onco-surgical approaches-geared beyond conventional gross total resections (GTR)-are limited by the impairment of adjacent eloquent areas at risk that may entail severe postoperative functional morbidity. Against this backdrop we analyzed our institutional database with regard to potential survival benefits of anterior temporal lobectomy as a paradigm for supra-total resection in patients with precisely temporal-located, non-eloquent glioblastoma. METHODS: Between 2012 and 2017, 38 patients with isolated temporal glioblastoma underwent GTR or temporal lobectomy at the authors' institution. Both groups of differing resection modalities were compared with regard to postoperative Karnofsky performance score (KPS), progression-free survival (PFS), and overall survival (OS). RESULTS: Patients with temporal lobectomy exhibited significantly superior median KPS at the 12 months follow-up compared to the GTR group (median KPS of 80 vs. 60, p = 0.04). Temporal lobectomy was associated with significantly prolonged PFS (p = 0.005) and OS (p = 0.002) coming up to 15 months (95% CI 9.7-22.1) and 23 months (95% CI 14.8-34.5) compared to 7 months (95% CI 3.3-8.3) and 11 months (95% CI 9.2-17.9) for the GTR group. Multivariate analysis revealed temporal lobectomy as the only predictor for both superior PFS (p = 0.037, OR 7.3, 95% CI 1.1-47.4) and OS (p = 0.04, OR 7.8, 95% CI 1.1-55.2). CONCLUSIONS: These results strongly suggest temporal lobectomy as an aggressive supra-total resection policy to constitute the surgical modality of choice for isolated temporal-located glioblastoma.

Chiari I-a 'not so' congenital malformation?

The term Chiari I malformation (CIM) is imbedded in the paediatric neurosurgical lexicon; however, the diagnostic criteria for this entity are imprecise, its pathophysiology variable, and the treatment options diverse. Until recently, CIM has been considered to be a discrete congenital malformation requiring a uniform approach to treatment. Increasingly, it is recognised that this is an oversimplification and that a more critical, etiologically based approach to the evaluation of children with this diagnosis is essential, not only to select those children who might be suitable for surgical treatment (and, of course those who might be better served by conservative management) but also to determine the most appropriate surgical strategy. Whilst good outcomes can be anticipated in the majority of children with CIM following foramen magnum decompression, treatment failures and complication rates are not insignificant. Arguably, poor or suboptimal outcomes following treatment for CIM reflect, not only a failure of surgical technique, but incorrect patient selection and failure to acknowledge the diverse pathophysiology underlying the phenomenon of CIM. The investigation of the child with 'hindbrain herniation' should be aimed at better understanding the mechanisms underlying the herniation so that these may be addressed by an appropriate choice of treatment.

Artificial Intelligence Based Hierarchical Clustering of Patient Types and Intervention Categories in Adult Spinal Deformity Surgery: Towards a New Classification Scheme that Predicts Quality and Value.

STUDY DESIGN: Retrospective review of prospectively-collected, multicenter adult spinal deformity (ASD) databases. OBJECTIVE: To apply artificial intelligence (AI)-based hierarchical clustering as a step toward a classification scheme that optimizes overall quality, value, and safety for ASD surgery. SUMMARY OF BACKGROUND DATA: Prior ASD classifications have focused on radiographic parameters associated with patient reported outcomes. Recent work suggests there are many other impactful preoperative data points. However, the ability to segregate patient patterns manually based on hundreds of data points is beyond practical application for surgeons. Unsupervised machine-based clustering of patient types alongside surgical options may simplify analysis of ASD patient types, procedures, and outcomes. METHODS: Two prospective cohorts were queried for surgical ASD patients with baseline, 1-year, and 2-year SRS-22/Oswestry Disability Index/SF-36v2 data. Two dendrograms were fitted, one with surgical features and one with patient characteristics. Both were built with Ward distances and optimized with the gap method. For each possible n patient cluster by m surgery, normalized 2-year improvement and major complication rates were computed. RESULTS: Five hundred-seventy patients were included. Three optimal patient types were identified: young with coronal plane deformity (YC, n = 195), older with prior spine surgeries (ORev, n = 157), and older without prior spine surgeries (OPrim, n = 218). Osteotomy type, instrumentation and interbody fusion were combined to define four surgical clusters. The intersection of patient-based and surgery-based clusters yielded 12 subgroups, with major complication rates ranging from 0% to 51.8% and 2-year normalized improvement ranging from -0.1% for SF36v2 MCS in cluster [1,3] to 100.2% for SRS self-image score in cluster [2,1]. CONCLUSION: Unsupervised hierarchical clustering can identify data patterns that may augment preoperative decision-making through construction of a 2-year risk-benefit grid. In addition to creating a novel AI-based ASD classification, pattern identification may facilitate treatment optimization by educating surgeons on which treatment patterns yield optimal improvement with lowest risk. LEVEL OF EVIDENCE: 4.

Transsphenoidal versus Transcranial Approach for Treatment of Tuberculum Sellae Meningiomas: A Systematic Review and Meta-analysis of Comparative Studies.

There is controversy regarding the surgical route selection for tuberculum sellae meningiomas (TSMs): the transsphenoidal (TS) or transcranial (TC) approach? We conducted a systematic review and meta-analysis to compare clinical outcomes and postoperative complications between two surgical approaches. Literature search was performed. Relevant articles were selected and evaluated. Data were extracted and analyzed. Eight articles comprising 550 patients met the inclusion criteria. Traditionally, the rates of gross total resection, tumor recurrence, visual improvement, and cerebrospinal fluid leakage were the most common outcomes of interest. We demonstrated that the TS approach was significantly associated with better visual outcomes but more frequent cerebrospinal fluid leakage, while the rates of tumor resection and recurrence showed no significant difference between groups. In addition to surgical results that were consistent with previous studies, we further evaluated the impact of approach selection on common postoperative complications, which were closely related to the recovery course and quality of life. We revealed that the risk of dysosmia was significantly higher in the TS group. There was no significant difference between groups regarding infection, intracranial hemorrhage, and endocrine disorders. Because of the relatively low evidence levels of included retrospective studies, it was difficult to reach a categorical conclusion about the optimal surgical approach for TSMs. Finally, we recommended that the TS approach was an alternative option in patients with smaller TSMs (<30 mm) and limited invasion of optic canals in experienced neurosurgical centers.

Microsurgical treatment of craniopharyngioma: Experiences on 183 consecutive patients.

This study aimed to summarize the clinical experiences and postoperative effects of microsurgical approaches for craniopharyngioma.A total of 183 craniopharyngioma patients who underwent microsurgical treatment since March 2009 to March 2015 in our hospital were included in current research. Surgical approaches were selected based on preoperative evaluations, including tumor locations, sizes, and growth patterns. Active measurements to manage water-electrolyte disorder and insipidus were taken for postoperative treatments. During the follow-up, patients were monitored for residual or recurrent tumor by postoperative contrast MRI scans done 1 to 3 months after surgery.The used surgical approaches were as follows: frontopterional approach (76 cases), anterior interhemispheric approach (58 cases), transcallosal approach (10 cases), transsphenoidal approach (15 cases), unilateral subfrontal approach (15 cases), and combined approaches (9 cases). Around 124 cases (72.7%) received total tumor resection, 37 patients (20.2%) underwent subtotal resection, and 13 patients (7.1%) underwent partial removal. No significant difference was found on the postoperative complications among the different microsurgical approaches (all, P > .05). A total of 111 cases had an intact pituitary stalk preservation and 26 cases had partially preserved stalks during surgery. Visual improvement was achieved in 54 patients and visual deterioration occurred in 22 cases. Postoperative insipidus appeared in 114 cases and water-electrolyte disorder occurred in 99 cases. The postsurgical follow-up ranged from 3 to 69 months with a mean duration of 27.3 months and 23 patients suffered recurrence.Based on careful preoperative evaluation, microsurgical treatments may be safe and effective approach to improve postoperative outcomes of craniopharyngioma patients.

Treatment Standards for Chronic Subdural Hematoma: Results from a Survey in Austrian, German, and Swiss Neurosurgical Units.

BACKGROUND: Although an abundance of literature about the treatment of chronic subdural hematoma is available, it provides little evidence to clarify which treatment is most successful. OBJECTIVE: The aim of this study was to examine and compare current clinical standards between several hospitals. METHODS: Chairmen of all neurosurgical units in Austria, Germany, and Switzerland, as listed on the national neurosurgical societies' websites, were invited to participate with a personal token to access a web-based survey. A total of 159 invitations were sent and up to 5 reminder e-mails. RESULTS: Eighty-four invitees (53%) completed the survey. The most common surgical intervention was a single burr hole in 52 (65%) of the responding neurosurgical units, double burr holes were performed as primary procedure in 16 centers (20%), a small osteoplastic craniotomy in 4 (5%), and a twist drill craniostomy in 8 (10%). Seventy-two (90%) would place a drain in estimated 75%-100% of cases or whenever possible/safe. Sixty-five used subdural-external drains, and 7 used subgaleal-external drains. Seventeen applied suction to the drains. Thirty-six (49%) agreed with the statement that watchful waiting was an option for the treatment of chronic subdural hematomas and 19 (23.4%) disagreed. Eighteen (23%) would consider corticosteroids and 34 (45%) tranexamic acid as part of their armamentarium for the treatment of subdural hematomas. CONCLUSIONS: The results of this survey reflect the current evidence available in literature. Although the benefits of using of a drain are widely recognized, no consensus regarding the type of drain and surgical approach to the hematoma was reached.

Facet injection trends in the Medicare population and the impact of bundling codes.

BACKGROUND CONTEXT: Interventional spine procedures have seen a steady increase in utilization over the last 10 to 20 years. In 2010, the Current Procedural Terminology (CPT) codes for facet injections were bundled with image guidance (fluoroscopic or computed tomography) and limited billing to a maximum of three levels. This was done in part because of increased utilization and to ensure that procedures were done appropriately with image guidance. PURPOSE: The study aimed to evaluate if the CPT code changes correlated with a decreased utilization of facet injections. STUDY DESIGN: This is a retrospective time series study. PATIENT SAMPLE: The sample was composed of 100% Medicare Part B claims submitted for facet joint injections from 2000 to 2012, as documented in the Centers for Medicare & Medicaid Services (CMS) Physician Supplier Procedure Summary (PSPS) master files. OUTCOME MEASURES: Procedure numbers and trends were the outcome measures. METHODS: The trends of facet injections were analyzed from 2000 to 2012 using the CMS PSPS master files. The total number of lumbosacral and cervical-thoracic facet injections was noted. Changes over those years were calculated with specific attention to 2010, when CPT were bundled with image guidance and injections were limited to no more than three levels. Also, to account for the growth in the Medicare population, a calculation was done of injections per 100,000 Medicare enrollees. No funding was used for this study. RESULTS: Facet injection utilization increased from 2000 to 2012, with an average growth rate of 11% per year for lumbosacral facet injections and 15% for cervical-thoracic facet injections (per 100,000 Medicare enrollees). The largest growth occurred from 2000 to 2006 (25% growth per year for lumbosacral and 32% for cervical-thoracic injections per 100,000 Medicare enrollees) and this leveled off from 2007 to 2012 (-3% growth per year for lumbosacral and -2% for cervical-thoracic injections per 100,000 Medicare enrollees). The biggest drop in these procedures was in 2010, when there was a drop of 14% for lumbosacral facet injections and 15% drop for cervical-thoracic facet injections (per 100,000 Medicare beneficiaries). CONCLUSIONS: Facet injection utilization notably increased from 2000 to 2006 but began to level off from 2007 to 2012. The most notable drop was in 2010, which correlated with the release of new CPT codes that bundled image guidance and limited procedures to three levels or less.

Minimally invasive spine surgery: systematic review.

Minimally invasive procedures in spine surgery have undergone significant development in recent times. These procedures have the common aim of avoiding biomechanical complications associated with some traditional destructive methods and improving efficacy. These new techniques prevent damage to crucial posterior stabilizers and preserve the structural integrity and stability of the spine. The wide variety of reported minimally invasive methods for different pathologies necessitates a systematic classification. In the present review, authors first provide a classification system of minimally invasive techniques based on the location of the pathologic lesion to be treated, to help the surgeon in selecting the appropriate procedure. Minimally invasive techniques are then described in detail, including technical features, advantages, complications, and clinical outcomes, based on available literature.

Effect of dural detachment on long-term tumor control for meningiomas treated using Simpson grade IV resection.

OBJECT: Meningiomas treated by subtotal or partial resection are associated with significantly shorter recurrence-free survival than those treated by gross-total resection. The Simpson grading system classifies incomplete resections into a single category, namely Simpson Grade IV, with wide variations in the volume and location of residual tumors, making it complicated to evaluate the achievement of surgical goals and predict the prognosis of these tumors. Authors of the present study investigated the factors related to necessity of retreatment and tried to identify any surgical nuances achievable with the aid of modern neurosurgical techniques for meningiomas treated using Simpson Grade IV resection. METHODS: This retrospective analysis included patients with WHO Grade I meningiomas treated using Simpson Grade IV resection as the initial therapy at the University of Tokyo Hospital between January 1995 and April 2010. Retreatment was defined as reresection or stereotactic radiosurgery due to postoperative tumor growth. RESULTS: A total of 38 patients were included in this study. Regrowth of residual tumor was observed in 22 patients with a mean follow-up period of 6.1 years. Retreatment was performed for 20 of these 22 tumors with regrowth. Risk factors related to significantly shorter retreatment-free survival were age younger than 50 years (p = 0.006), postresection tumor volume of 4 cm(3) or more (p = 0.016), no dural detachment (p = 0.001), and skull base location (p = 0.016). Multivariate analysis revealed that no dural detachment (hazard ratio [HR] 6.42, 95% CI 1.41-45.0; p = 0.02) and skull base location (HR 11.6, 95% CI 2.18-218; p = 0.002) were independent risk factors for the necessity of early retreatment, whereas postresection tumor volume of 4 cm(3) or more was not a statistically significant risk factor. CONCLUSIONS: Compared with Simpson Grade I, II, and III resections, Simpson Grade IV resection includes highly heterogeneous tumors in terms of resection rate and location of the residual mass. Despite the difficulty in analyzing such diverse data, these results draw attention to the favorable effect of dural detachment (instead of maximizing the resection rate) on long-term tumor control. Surgical strategy with an emphasis on detaching the tumor from the affected dura might be another important option in resection of high-risk meningiomas not amenable to gross-total resection.

Health-related quality of life before and after pediatric epilepsy surgery: the influence of seizure outcome on changes in physical functioning and social functioning.

Health-related quality of life (HRQOL) is an important outcome in pediatric epilepsy surgery, but there are few studies that utilize presurgical ratings to assess the effect of surgery on HRQOL. We collected parental ratings on the Quality of Life in Childhood Epilepsy (QOLCE) questionnaire for 28 children who participated in neuropsychological assessment before and after epilepsy surgery. Our results revealed significant improvements in overall HRQOL after surgery, especially in physical and social activities. These changes were apparent despite generally unchanged intellectual and psychological functioning. Children with better seizure outcome had more improvement in HRQOL; however, improvements were not statistically different among children with Engel class I, II, and III outcomes. Our results suggest that children can experience significant improvements in HRQOL following epilepsy surgery even when neuropsychological functioning remains unchanged. Moreover, improvements in HRQOL appear evident in children who experience any worthwhile improvement in seizure control (Engel class III or better).

[Neurosurgical treatments for pain]. / Les traitements neurochirurgicaux de la douleur.

Pain represents the most frequent symptom faced by general practitioners and is associated with 60% of neurological troubles. Pain consists in a conscious, subjective, unpleasant and protective sensory experience transmitted by thermoalgic pathways in the central nervous system (nociceptive pain). Lesioning of peripheral or central sensory pathways can also generate pain associated with hypoesthesia (phantom or neuropathic pain). Since the 1920's, neurosurgeons have attempted to alleviate nociceptive and neuropathic chronic pain by interrupting (irreversible interruptive techniques) thermoalgic fibers (neurotomies, rhizotomies, cordotomies, tractotomies, thalamotomies, cingulotomies). Some of them (neurotomies, rhizotomies) are still used today when all medications have failed. They can provide immediate and tremendous pain relief like in trigeminal neuralgia. However, the technique, when not sufficiently selective, can generate a neuropathic pain and then a short-lating pain relief. Increasing knowledge on pathophysiological mechanisms of pain allowed surgery to interfere with the functioning of the sensory circuits without lesioning and to modulate neuronal activity in order to reduce pain (neuromodulation). Non-lesioning modulating techniques (then reversible) appeared (deep brain stimulation, epidural spinal cord or motor cortex stimulation, intrathecal infusion, radiosurgery) and are currently applied to efficiently alleviate neuropathic pain.

Three years of neurosurgical experience in a multinational field hospital in northern Afghanistan.

BACKGROUND: Since July 2007, neurosurgical services have been continuously available in a multinational Role 3 field hospital in Mazar-e-Sharif (MeS), Afghanistan. In this paper, we analyse a 3-year neurosurgical caseload experience. METHODS: We retrospectively analysed the neurosurgical caseload at a Role 3 medical treatment facility in northern Afghanistan between October 2007 and October 2010. The cases were divided into acute, urgent and elective procedures and into cranial, spinal, peripheral nerve and miscellaneous surgeries. RESULTS: A total of 190 surgeries were performed. Of these, 50 operations (26.3%) were acute procedures that were conducted to save lives or preserve neurological function. In addition, operations included 47 urgent (24.7%) and 93 elective (49%) procedures. There were 58 cranial surgeries (30.5%), 113 spinal surgeries (59.5%), 11 peripheral nerve surgeries (5.8%), and 8 miscellaneous surgeries (4.2%). Surgical treatment was provided to 13 International Security Assistance Force (ISAF) soldiers (6.8%), 22 members of the Afghan National Security Forces (11.6%), and 155 Afghan civilians (81.6%). CONCLUSIONS: The primary mission of the field hospital is to provide sick, injured or wounded ISAF personnel with medical and surgical care, the outcome of which must correspond to standards prevailing in Germany. Only a very small number of neurosurgical operations performed in MeS met the criteria established by this mission statement and by the modern principles of damage-control wartime surgery. This is completely different from the experience reported by other ISAF nations in eastern and southern Afghanistan.

[Neurosurgery of the spasticity syndrome in children cerebral palsy].

The review is devoted to main neurosurgical approaches to the treatment of the spasticity syndrome in children cerebral palsy. Neurosurgical procedures are divided into destructive and neuromodulating. The former included posterior selective rhizotomy, selective neurotomy and destructive operations on subcortical brain structures. The latter group included electrostimulation of brain and spinal cord structures and implantation of pumps for the chronic intrathecal baclofen (lioresal) infusion. Each method is considered in a historical aspect. Details of clinical application, positive and negative sides of the methods are described.

A new endoscopic surgical classification and invasion criteria for pituitary adenomas involving the cavernous sinus.

AIM: There are two major problems for the pituitary adenomas invading the Cavernous Sinus (CS); differentiation of extension and invasion and inability to demonstrate the medial wall via preoperative imaging methods. Two important corridors are defined in endoscopic cavernous sinus approaches; the lateral and medial corridor. MATERIAL AND METHODS: A retrospective analysis was performed in 400 endoscopic transphenoidal approaches and 360 pituitary adenomas underwent endoscopic transphenoidal surgery in our department between September 1997 and December 2010. 48 patients affected by the tumours involving the cavernous sinus were included in this study. RESULTS: We performed an intraoperative evaluation of cavernous sinus invasion considering visualization of the medial wall defect, intracavernous ICA segments, minor tumour extensions through small focal pit holes of the medial wall of CS or confirming carotid segments of CS by micro-doppler. Cavernous sinus involvement was classified into three types according to the medial and lateral corridor extension of the tumor as 25 isolated medial corridor involvement (Type I), 5 isolated lateral corridor involvement (Type II) and 18 total involvement (Type III). CONCLUSION: Our classification depends on fully surgical endoscopic approach supported by neuroimaging techniques and anatomical studies and shows a good predictive value for all cavernous sinus involvement.