Trends in Endoscopic and Microscopic Approaches to Transsphenoidal Pituitary Surgery in the US

OBJECTIVES

Among the transsphenoidal (TSS) approaches to pituitary tumors, the microscopic approach (MA) has historically been the predominant technique with the increasing adoption of the endoscopic approach (EA). This study investigates national trends in TSS approaches and postoperative outcomes for MA and EA through 2021.

METHODS

The TriNetX database was queried for patients undergoing TSS (MA and EA) between 2010 and 2021. Data were collected on demographics, geographic distribution of surgical centers, postoperative complications, stereotactic radiosurgery (SRT), repeat surgery, and postoperative emergency department (ED) visits.

RESULTS

8644 TSS cases were queried between 2010 and 2021. MA rates were highest until 2013 when rates of EA (52%) surpassed MA (48%) and continued to increase through 2021 (81%). From 2010 to 2015 EA had higher odds of a postoperative CSF leak (OR 3.40) and diabetes insipidus (DI (OR 2.30)) versus MA (p < 0.05); from 2016 to 2021 differences were not significant. Although there was no significant difference among approaches from 2010 to 2015 for syndrome of inappropriate antidiuretic hormone (SIADH), hyponatremia, or bacterial meningitis, from 2016 to 2021 EA had lower odds of SIADH (OR 0.54) and hyponatremia (OR 0.71), and higher odds of meningitis (OR 1.79) versus MA (p < 0.05). EA had higher odds of additional surgery (either EA or MA) after initial surgery from 2010 to 2021. From 2010 to 2015 EA had lower odds of postoperative SRT compared to MA, whereas in 2016-2021 there was no statistical difference among approaches.

CONCLUSION

This study demonstrates increasing EA adoption for TSS in the United States since 2013. Complication rates have overall improved for EA compared to MA, potentially as a result of improving surgeon familiarity and experience.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2135-2140, 2023.

Selection of Optimal Functional Lymphatic Vessel Cutoff Size in Supermicrosurgical Lymphaticovenous Anastomosis in Lower Extremity Lymphedema

BACKGROUND

Functional lymphatic vessels are essential for supermicrosurgical lymphaticovenous anastomosis. Theoretically, the larger the lymphatic vessel, the better the flow. However, large lymphatic vessels are not readily available. Since the introduction of lymphaticovenous anastomosis, no guidelines have been set as to how small a lymphatic vessel is still worthwhile for anastomosis.

METHODS

In this longitudinal cohort study, unilateral lower limb lymphedema patients who underwent lymphaticovenous anastomosis between March of 2016 and January of 2019 were included. Demographic data and intraoperative findings including the number and size of lymphatic vessels were recorded. The cutoff size was determined by receiver operating characteristic curve analysis, based on the functional properties of lymphatic vessels. Clinical correlation was made with post-lymphaticovenous anastomosis volume measured by magnetic resonance volumetry.

RESULTS

A total of 141 consecutive patients (124 women and 17 men) with a median age of 60.0 years (range, 56.7 to 61.2 years) were included. The cutoff size for a functional lymphatic vessel was determined to be 0.50 mm (i.e., lymphatic vessel0.5) from a total of 1048 lymphatic vessels. Significant differences were found between the number of lymphatic vessels0.5 anastomosed (zero to one, two to three, and greater than over equal to four lymphatic vessels0.5), the median post-lymphaticovenous anastomosis volume reduction (in milliliters) (p < 0.001), and the median percentage volume reduction (p = 0.012).

CONCLUSIONS

Lymphatic vessel0.5 can be a valuable reference for lymphaticovenous anastomosis. Post-lymphaticovenous anastomosis outcome can be enhanced with the use of lymphatic vessel0.5 for anastomoses.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Percutaneous Transforaminal Endoscopic Discectomy Versus Open Microdiscectomy for Lumbar Disc Herniation: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To give a systematic overview of effectiveness of percutaneous transforaminal endoscopic discectomy (PTED) compared with open microdiscectomy (OM) in the treatment of lumbar disk herniation (LDH).

SUMMARY OF BACKGROUND DATA

The current standard procedure for the treatment of sciatica caused by LDH, is OM. PTED is an alternative surgical technique which is thought to be less invasive. It is unclear if PTED has comparable outcomes compared with OM.

METHODS

Multiple online databases were systematically searched up to April 2020 for randomized controlled trials and prospective studies comparing PTED with OM for LDH. Primary outcomes were leg pain and functional status. Pooled effect estimates were calculated for the primary outcomes only and presented as standard mean differences (SMD) with their 95% confidence intervals (CI) at short (1-day postoperative), intermediate (3-6 months), and long-term (12 months).

RESULTS

We identified 2276 citations, of which eventually 14 studies were included. There was substantial heterogeneity in effects on leg pain at short term. There is moderate quality evidence suggesting no difference in leg pain at intermediate (SMD 0.05, 95% CI -0.10-0.21) and long-term follow-up (SMD 0.11, 95% CI -0.30-0.53). Only one study measured functional status at short-term and reported no differences. There is moderate quality evidence suggesting no difference in functional status at intermediate (SMD -0.09, 95% CI -0.24-0.07) and long-term (SMD -0.11, 95% CI -0.45-0.24).

CONCLUSION

There is moderate quality evidence suggesting no difference in leg pain or functional status at intermediate and long-term follow-up between PTED and OM in the treatment of LDH. High quality, robust studies reporting on clinical outcomes and cost-effectiveness on the long term are lacking.Level of Evidence: 2.

End-to-Side Microvascular Anastomosis on Rat Femoral Vessels Using Only 2-Throw Knot Interrupted Sututres - Evaluation of Feasibility and Patency Rates on Rat Femoral Vessels Model

BACKGROUND

The use of a 3-throw knot for anastomosis by microvascular neurosurgeons is the usual standard. There is an inherent belief that the third throw adds extra security to the knot; however, the third throw can make the knot heavy and unbalanced and can exert undue extra pressure on the opposing walls of the small-caliber intracranial vessels. This study evaluated the feasibility and efficiency of 2-throw reef knot interrupted sutures for an end-to-side microvascular anastomosis.

METHODS

A prospective observational study of end-to-side anastomosis using a femoral artery-to-vein model was performed in 30 Sprague-Dawley rats. All anastomoses were done using 2-throw reef knot interrupted sutures. Ten procedures each were done by the heel-first, toe-first, and classic 2-ends techniques. Individual parameters were recorded for analysis. The delayed patency was confirmed by reexploration after a mean duration of 19.82 ± 8.12 days.

RESULTS

The overall patency rates were 100% in the immediate period and 96.43% (27 of 28) in the delayed period. The average clamping time, average suturing time, and the average time per suture were 65.48 ± 16.93 minutes, 40.94 ± 11.22 minutes, and 3.18 ± 1.10 minutes, respectively. Two rats died in the postoperative period.

CONCLUSIONS

The end-to-side microvascular anastomosis with 2-throw reef knots is feasible, with excellent immediate and delayed patency rates.

A Protocol for Performing Reconstructive Microsurgery on Patients With COVID-19

On March 11, 2020, the World Health Organization declared COVID-19 to be a pandemic, challenging health care systems all over the world. National health care systems have reorganized to cope with the disease. Surgical services departments around the world have been affected and elective surgical procedures have been postponed to conserve medical resources. When a patient with COVID-19 requires an urgent microsurgical free flap due to trauma or a tumor, personnel from the health care facility must have a protocol in place to follow for the patient's care and follow-up. In this article, we present our protocol for patients with COVID-19 requiring reconstructive microsurgery.

Trends in endoscopic and microscopic transsphenoidal surgery: a survey of the international society of pituitary surgeons between 2010 and 2020

PURPOSE

This comparative survey of surgical practice patterns between 2010 and 2020 aims to elicit trends in practice patterns for transsphenoidal surgery and to identify areas for improvement.

METHODS

Web-based surveys were sent to the International Society of Pituitary Surgeons via a membership listserv in 2010 and 2020. These 33-item surveys collected information on demographics, surgical approach, perceived advantages and disadvantages, and recommendations for improvements. Statistical analyses were conducted using the Mann-Whitney U test for continuous variables and Fisher's exact test for categorical variables.

RESULTS

There were 51 respondents in 2010 and 82 respondents in 2020. The majority were full-time academic surgeons from the United States or Europe. Preference for a purely endoscopic technique increased from 43% in 2010 to 87% in 2020. Preference for routinely working with an otolaryngologist or second neurosurgeon increased from 35 to 51%. Most surgeons (74%) reported that they were more likely to achieve a greater extent of resection with the endoscope, though 51% noted increased operating time. The most commonly rated advantage (34%) of endoscopic TSS was fewer postoperative nasoseptal perforations; the most commonly (34%) rated disadvantage was more postoperative complications, including cerebrospinal fluid leak. Respondents were divided on whether microscopic TSS should continue to be taught in residency. Many (32%) advocated for improved endoscopic instrumentation and team training.

CONCLUSION

Endoscopic TSS is now the clearly preferred method for surgery amongst a cohort of higher-volume academic neurosurgeons. This trend is likely to continue, and this provides guidelines for future training.

Surgery as a Viable Alternative First-Line Treatment for Prolactinoma Patients. A Systematic Review and Meta-Analysis

CONTEXT

The improved remission and complication rates of current transsphenoidal surgery warrant reappraisal of the position of surgery as a viable alternative to dopamine agonists in the treatment algorithm of prolactinomas.

OBJECTIVE

To compare clinical outcomes after dopamine agonist withdrawal and transsphenoidal surgery in prolactinoma patients.

METHODS

Eight databases were searched up to July 13, 2018. Primary outcome was disease remission after drug withdrawal or surgery. Secondary outcomes were biochemical control and side effects during dopamine agonist treatment and postoperative complications. Fixed- or random-effects meta-analysis was performed to estimate pooled proportions. Robustness of results was assessed by sensitivity analyses.

RESULTS

A total of 1469 articles were screened: 55 (10 low risk of bias) on medical treatment (n = 3564 patients) and 25 (12 low risk of bias) on transsphenoidal surgery (n = 1836 patients). Long-term disease remission after dopamine agonist withdrawal was 34% (95% confidence interval [CI], 26-46) and 67% (95% CI, 60-74) after surgery. Subgroup analysis of microprolactinomas showed 36% (95% CI, 21-52) disease remission after dopamine agonist withdrawal, and 83% (95% CI, 76-90) after surgery. Biochemical control was achieved in 81% (95% CI, 75-87) of patients during dopamine agonists with side effects in 26% (95% CI, 13-41). Transsphenoidal surgery resulted in 0% mortality, 2% (95% CI, 0-5) permanent diabetes insipidus, and 3% (95% CI, 2-5) cerebrospinal fluid leakage. Multiple sensitivity analyses yielded similar results.

CONCLUSIONS

In the majority of prolactinoma patients, disease remission can be achieved through surgery, with low risks of long-term surgical complications, and disease remission is less often achieved with dopamine agonists.

Microsurgical dissection of Sylvian fissure-short technical videos of third generation cerebrovascular neurosurgeons

Background

Multiple intracranial pathologies, including aneurysms of the middle cerebral artery, distal basilar artery, and suprasellar pathologies require the microsurgical opening of the Sylvian fissure. Delicate splitting of the arachnoid and safe microdissection of the veins, arteries, and brain parenchyma is the key to successful surgery through the Sylvian fissure corridor. We hypothesize that the geographical and historical environment in which neurosurgeons learn their operative skills is subject to a number of extrinsic influences, including cultural nuances of surgical techniques. Here we try to illustrate some cultural differences and technical aspects of the opening of the Sylvian fissure by four “third generation” cerebrovascular neurosurgeons from three different continents.

Methods

In the video analysis, various microsurgical aspects, including the opening style of the Sylvian fissure, handedness, use of sharp or blunt microinstruments, use of retractors, use of high magnification, and handling of bridging veins are presented.

Results

The video illustrates the two distinct Sylvian fissure opening styles, namely sharp and blunt microdissection, as well as the extent of the opening namely a wide and focal splitting.

Conclusion

The edited video underlines nuances and differences of a few major technical aspects that are perhaps typical to certain surgical environments and cultures. These microsurgical nuances and styles are useful pearls that can be mastered with training by any novice neurosurgeon.

Electronic supplementary material

The online version of this article (10.1007/s00701-019-03999-x) contains supplementary material, which is available to authorized users.

Nanomechanical mapping helps explain differences in outcomes of eye microsurgery: A comparative study of macular pathologies

Many ocular diseases are associated with an alteration of the mechanical and the material properties of the eye. These mechanically-related diseases include macular hole and pucker, two ocular conditions due to the presence of abnormal physical tractions acting on the retina. A complete relief of these tractions can be obtained through a challenging microsurgical procedure, which requires the mechanical peeling of the internal limiting membrane of the retina (ILM). In this paper, we provide the first comparative study of the nanoscale morphological and mechanical properties of the ILM in macular hole and macular pucker. Our nanoscale elastic measurements unveil a different bio-mechanical response of the ILM in the two pathologies, which correlates well to significant differences occurring during microsurgery. The results here presented pave the way to the development of novel dedicated microsurgical protocols based on the material ILM properties in macular hole or pucker. Moreover, they contribute to clarify why, despite a common aetiology, a patient might develop one disease or the other, an issue which is still debated in literature.

Endoscopic Versus Microscopic Transsphenoidal Surgery in the Treatment of Pituitary Adenoma: A Systematic Review and Meta-Analysis

BACKGROUND

Inconsistent findings have been reported regarding the efficacy and safety of endoscopic and microscopic transsphenoidal surgery for pituitary adenoma. This study aimed to assess the benefits and shortcomings of these surgical methods in patients with pituitary adenoma.

METHODS

The electronic databases PubMed, Embase, and the Cochrane Library were systematically searched, as well as proceedings of major meetings. Eligible studies with a retrospective or prospective design that evaluated endoscopic versus microscopic methods in patients with pituitary adenoma were included. Primary outcomes included gross tumor removal, cerebrospinal fluid leak, diabetes insipidus, and other complications.

RESULTS

Overall, 23 studies (4 prospective and 19 retrospective) assessing 2272 patients with pituitary adenoma were included in the final analysis. Endoscopic transsphenoidal surgery was associated with a higher incidence of gross tumor removal (odds ratio, 1.52; 95% confidence interval, 1.11-2.08; P = 0.009) than those with microscopic transsphenoidal surgery. In addition, endoscopic transsphenoidal surgery had no significant effect on the risk of cerebrospinal fluid leak, compared with microscopic transsphenoidal surgery. Furthermore, endoscopic transsphenoidal surgery was associated with a 22% reduction in risk of diabetes insipidus compared with microscopic transsphenoidal surgery, but the difference was not statistically significant. Endoscopic transsphenoidal surgery significantly reduced the risk of septal perforation (odds ratio, 0.29; 95% confidence interval, 0.11-0.78; P = 0.014) and was not associated with the risk of meningitis, epistaxis, hematoma, hypopituitarism, hypothyroidism, hypocortisolism, total mortality, and recurrence.

CONCLUSIONS

Endoscopic transsphenoidal surgery is associated with higher gross tumor removal and lower incidence of septal perforation in patients with pituitary adenoma. Future large-scale prospective randomized controlled trials are needed to verify these findings.

Twelve tips for postgraduate or undergraduate medics building a basic microsurgery simulation training course

Microsurgery is used in a variety of surgical specialties, including Plastic Surgery, Maxillofacial Surgery, Ophthalmic Surgery, Otolaryngology and Neurosurgery. It is considered one of the most technically challenging fields of surgery. Microsurgical skills demand fine, precise and controlled movements, and microsurgical skill acquisition has a steep initial learning curve. Microsurgical simulation provides a safe environment for skill acquisition before operating clinically. The traditional starting point for anyone wanting to pursue microsurgery is a basic simulation training course. We present twelve tips for postgraduate and undergraduate medics on how to set up and run a basic ex-vivo microsurgery simulation training course suitable for their peers.

Pediatric Microvascular Reconstruction: A Report from the Microvascular Committee

BACKGROUND: Free tissue transfer is an integral part of modern head and neck surgery in the adult population. Its use in the pediatric population has not been well described. Recently, there has been an increase in the application of these techniques in the pediatric population. The morbidity of free tissue transfer in small pediatric patients and its effect on growth has not been well described.

OBJECTIVE: To evaluate the utility of microvascular reconstruction techniques in the pediatric population.

STUDY DESIGN: A consensus study was performed by the microvascular committee of the American Academy of Otolaryngology-Head and Neck Surgery. Thirty active microvascular surgeons reviewed their databases to find patients less than 21 years of age who underwent free tissue transfer.

RESULTS: 49 free tissue transfers performed between 1999 and 2005. The mean age was 12.1 years (age range, 3–21). The types of flaps transferred were radial forearm (10), fibula (21), rectus abdominus (7), scapula (1), latissimus dorsi (3), groin (1), gracillus (4), and jejunum (2). Morbidity at the donor site was relatively minimal. Five patients developed wound breakdown. One of these required return to the operating room. Morbidity at the reconstructed site was also rare. Patients were followed for an average of 49 months (range, 1–131 months), and no problems were noted with growth at the donor or recipient sites.

CONCLUSIONS: Free flaps in the pediatric population have morbidity and survival similar to those in the adult population.

SIGNIFICANCE: While indications differ from those in the adult population, these techniques are viable and valuable and should be considered in the pediatric reconstructive paradigm.

Clean, fast and preserving normal anatomy: "the Helsinki revolution" in microneurosurgery

After the senior author took chairmanship in Helsinki University Hospital in, he led the department into making neurosurgical operations much faster, safer and workflow more efficient, and at the same time maintaining high surgical quality and results. The aim was to describe the philosophies and style of Helsinki Microneurosurgery. The philosophies of Helsinki Neurosurgery are categorized into two concepts: The operation room TEAM concept and the main principle "Simple, clean, fast and respecting the normal anatomy". The way to be efficient is to find good methods based on logic, reason and experience. Specific and systematic procedures before the microneurosurgery followed by high quality skills under the microscope are of utmost importance. Moreover, intraoperatively, neuroanesthesia has to provide good surgical conditions. Today, Helsinki University Central hospital Department of Neurosurgery has an annual workflow 3500 neurosurgical operations. We believe that microneurosurgical treatment remains to be important for years ahead, and neurosurgeons of great hearts, minds and skills are welcomed all over the world.

Poor diagnostic accuracy of transcranial motor and somatosensory evoked potential monitoring during brainstem cavernoma resection

OBJECTIVE

Microsurgical resection of brainstem cavernomas carries a high risk of new postoperative morbidity such as cranial nerve, motor and sensory deficits as well as functional deterioration. Intraoperative monitoring is used to avoid impending damage to these highly eloquent tracts. However, data on neurophysiological monitoring during resection of brainstem cavernomas are lacking.

METHODS

Consecutive patients with brainstem cavernomas who underwent surgical removal from June 2007 to December 2014 were retrospectively analysed. Transcranial motor-evoked potential (MEP) and somatosensory-evoked potential (SSEP) monitorings were performed in all cases. The evoked potential (EP) monitoring data were reviewed and related to new postoperative motor and sensory deficits and postoperative imaging. Clinical outcomes were assessed during follow-up.

RESULTS

Twenty-six consecutive patients with brainstem cavernoma underwent 27 surgical resections within this study. MEP and SSEP monitoring was technically feasible in 26 and 27 cases, respectively. MEP sensitivity and specificity were 33 and 88 %, respectively. MEP positive and negative predictive values were 28 and 78 %, respectively. SSEP sensitivity and specificity were 20 and 81 %, respectively. SSEP positive and negative predictive values were 20 and 81 %, respectively.

CONCLUSION

In continuous MEP and SSEP monitoring during brainstem cavernoma microsurgery, high rates of false-positive and -negative results are encountered, resulting in low positive and relatively high negative predictive values. Careful interpretation of the intraoperative monitoring results is essential in order to avoid potentially unjustified termination of brainstem cavernoma resection.

Improving outcomes in patients with vestibular schwannomas: microsurgery versus radiosurgery

Vestibular schwannomas (VSs) account for 6% of all intracranial tumors. Historically, VSs have been treated with microsurgery (MS); however, stereotactic radiosurgery (SRS) has emerged as a viable alternative. This review seeks to compare the tumor control rates, functional outcomes, and costs associated with these two modalities. A focused review of the published literature (1966-2012) was conducted comparing outcomes between MS and SRS in those with VS. Outcomes of interest included hearing preservation, facial nerve preservation, tumor control, and cost-effectiveness. Three level 2 studies, eight level 3 studies, and several level 4 studies were reviewed and assessed. Evidence from level 2 studies show that SRS (40-68%) results in higher rates of serviceable hearing compared to MS (0-5%), and higher rates of facial nerve preservation are likewise seen after SRS (98-100%) compared to MS (66-83%) in patients with tumors <3 cm in size. Complications vary as expected by treatment modality, with CSF leak, tinnitus, and trigeminal symptoms being among the most common complications following MS. Hydrocephalus, tinnitus, and trigeminal symptoms were reported in a small percentage of patients after SRS. Tumor control is comparable between MS and SRS for tumors <3cm in size. Total costs for MS can reach over two times higher than for SRS, although long-term follow-up data is needed. SRS has been shown to be efficacious and have a lower morbidity in most patients with tumors that are <3cm. SRS can be considered as the primary modality of choice for treatment of most VS that are <3cm.

A national survey of program director opinions of core competencies and structure of hand surgery fellowship training

PURPOSE

We assessed hand surgery program directors' opinions of essential components of hand surgery training and potential changes in the structure of hand surgery programs.

METHODS

We recruited all 74 program directors of Accreditation Council of Graduate Medical Education-accredited hand surgery fellowship programs to participate. We designed a web-based survey to assess program directors' support for changes in the structure of training programs and to assess opinions of components that are essential for graduates to be proficient. Respondents were asked to rate 9 general areas of practice, 97 knowledge topics, and 172 procedures. Each component was considered essential if 50% or more of respondents thought that graduates must be fully knowledgeable of the topic and be able to perform the procedure at the end of training.

RESULTS

The response rate was 84% (n = 62). A minority of program directors (n = 15; 24%) supported creation of additional pathways for hand surgery training, and nearly three-quarters (n = 46; 74%) preferred a fellowship model to an integrated residency model. Most program directors (n = 40; 65%) thought that a 1-year fellowship was sufficient to train a competent hand surgeon. Wrist, distal radius/ulna, forearm, and peripheral nerve conditions were rated as essential areas of practice. Of the detailed components, 76 of 97 knowledge topics and 98 of 172 procedures were rated as essential. Only 48% respondents (n = 30) rated microsurgery as it relates to free tissue transfer as essential. However, small and large vessel laceration repairs were rated as essential by 92% (n = 57) and 77% (n = 48) of respondents, respectively.

CONCLUSIONS

This study found resistance to prolonging the length of fellowship training and introduction of an integrated residency pathway. To train all hand surgeons in essential components of hand surgery, programs must individually evaluate exposure provided and find innovative ways to augment training when necessary.

CLINICAL RELEVANCE

Studies of curriculum content in hand surgery affect the future scope of hand surgery practice and highlight areas in need of reform and enhancement.

Evaluating performance of the spetzler-martin supplemented model in selecting patients with brain arteriovenous malformation for surgery

BACKGROUND AND PURPOSE

Our recently proposed point scoring model includes the widely-used Spetzler-Martin (SM)-5 variables, along with age, unruptured presentation, and diffuse border (SM-Supp). Here we evaluate the SM-Supp model performance compared with SM-5, SM-3, and Toronto prediction models using net reclassification index, which quantifies the correct movement in risk reclassification, and validate the model in an independent data set.

METHODS

Bad outcome was defined as worsening between preoperative and final postoperative modified Rankin Scale score. Point scores for each model were used as predictors in logistic regression and predictions evaluated using net reclassification index at varying thresholds (10%-30%) and any threshold (continuous net reclassification index >0). Performance was validated in an independent data set (n=117).

RESULTS

Net gain in risk reclassification was better using the SM-Supp model over a range of threshold values (net reclassification index=9%-25%) and significantly improved overall predictions for outcomes in the development data set, yielding a continuous net reclassification index of 64% versus SM-5, 67% versus SM-3, and 61% versus Toronto (all P<0.001). In the validation data set, the SM-Supp model again correctly reclassified a greater proportion of patients versus SM-5 (82%), SM-3 (85%), and Toronto models (69%).

CONCLUSIONS

The SM-Supp model demonstrated better discrimination and risk reclassification than several existing models and should be considered for clinical practice to estimate surgical risk in patients with brain arteriovenous malformation.

Replantation of scalp avulsion following a go-kart accident: a case report

With the development of microsurgery, successfully replanted cases of scalp avulsions have been reported. In spite of previous publications of replantations based on a single artery and vein, it is now accepted that multiple anastomoses increase the success rate. We present herein the case of a successfully replanted avulsion in a child who caught her hair in a go-kart motor belt, and we discuss the mechanism of injury and number of anastomoses.

Quantitative measures of performance in microvascular anastomoses

OBJECTIVE

Methods of evaluating surgical performance are mainly subjective. This study introduces a method of evaluating surgical performance using a quantitative analysis of tool tip kinematics.

METHODS

One experienced surgeon performed eight rat microvascular anastomoses over a 2-day interval. An optoelectronic motion analysis system acquired tool tip trajectories at frequencies of 30 Hz. On the basis of a hierarchical decomposition, the procedure was segmented into specific surgical subtasks (free space movement, needle placement and knot throws) from which characteristic measures of performance (tool tip trajectory, excursion and velocity) were evaluated. Comparisons of performance measures across each procedure were indexed (D scale) using the Kolmogorov-Smirnov statistic.

RESULTS

Despite the marker occlusions, tool tip data were obtained 92 +/- 7% (mean +/- SD) of the time during manipulation tasks. Missing data segments were interpolated across gaps of less than 10 sample points with errors less than 0.4 mm. The anastomoses were completed in 27 +/- 4 min (range 20.5-31.4 min) with 100% patency. Tool tip trajectories and excursions were comparable for each hand, while right and left hand differences were found for velocity. Performance measures comparisons across each procedure established the benchmark for an experienced surgeon. The D-scale range was between 0 and 0.5.

CONCLUSION

The study establishes a reproducible method of quantitating surgical performance. This may enhance assessment of surgical trainees at various levels of training.

Microdiscectomy compared with standard discectomy: an old problem revisited with new outcome measures within the framework of a spine surgical registry

Studies comparing the relative merits of microdiscectomy and standard discectomy report conflicting results, depending on the outcome measure of interest. Most trials are small, and few have employed validated, multidimensional patient-orientated outcome measures, considered essential in outcomes research. In the present study, data were collected prospectively from six surgeons participating in a surgical registry. Inclusion criteria were: lumbar/lumbosacral degenerative disease; discectomy/sequestrectomy without additional fusion/stabilisation; German or English-speaking. Before and 3 and 12 months after surgery, patients completed the Core Outcome Measures Index comprising questions on leg/buttock pain, back pain, back-related function, symptom-specific well-being, general quality-of-life, and social and work disability. At follow-up, they rated overall satisfaction, global outcome, and perceived complications. Compliance with the registry documentation was excellent: 87% for surgeons (surgery forms), 91% for patients (for 12 months follow-up). 261 patients satisfied the inclusion criteria (225 microdiscectomy, 36 standard discectomy). The standard discectomy group had significantly greater blood-loss than the microdiscectomy (P < 0.05). There were no group differences in the proportion of surgical complications or duration of hospital stay (P > 0.05). The groups did not differ in relation to any of the patient-orientated outcomes or individual outcome domains (P > 0.05). Though not equivalent to an RCT, the study included every single eligible patient in our Spine Center and allowed surgeons to use their regular procedure; it hence had extremely high external validity (relevance/generalisability). There was no clinically relevant difference in outcome after lumbar disc excision dependent on the use of the microscope. The decision to use the microscope should rest with the surgeon.

Surgical management of giant craniopharyngiomas

INTRODUCTION

Multimodal treatment in the management of giant craniopharyngiomas (>4 cm in diameter) is necessary to obtain optimal results, and includes conservative or palliative treatment and "aggressive" removal. The significance of a new treatment algorithm including direct surgical resection with the intent to avoid radiation therapy and regrowth will be discussed here.

MATERIALS AND METHODS

Between January 1996 and January 2005 16 patients were diagnosed with giant craniopharyngiomas. Two of them underwent only cyst aspiration because of their advanced age and/or lack of improvement of neuropsychological deficits. One patient underwent transsphenoidal operation and in the remaining 13 transcranial surgery was performed. Four additional patients underwent surgery for recurrence. The prospective protocol included pre- and post-operative dynamic endocrine tests, high field 1.5 T MRI and ophthalmological as well as neuropsychological examinations.

RESULTS

In resectable tumours, the rate of total removal was ten out of 12 with two recurrences. In the remaining two patients with recurrences this intention was abandoned because of a firm tumour or a deteriorating neuropsychological status prior to the scheduled additional operation. There was no mortality and the morbidity rate was 6.3%. Visual function improved in 11, was unchanged in one and deteriorated in two patients. Secretion of different adenohypophyseal hormones deteriorated after tumour resection in one to three patients, and new diabetes insipidus occurred in six patients. There was no permanent deterioration of neuropsychological function.

CONCLUSION

Special reference is given to direct resection of tumours at an optimal timing within this management. If hypothalamic disturbances are absent or improving due to pre-treatment (medical therapy, symptomatic surgery), giant craniopharyngiomas can be surgically removed in more than two of three patients with low morbidity and only moderate deterioration of endocrine function. The latter has to be accepted when curative surgery is intended, but even then, recurrences cannot be prevented. Contraindication for curative surgery is persisting hypothalamic damage necessitating conservative treatment modalities.

Giant olfactory groove meningioma: ophthalmological and cognitive outcome after bifrontal microsurgical approach

OBJECT

Olfactory groove meningiomas arise in the midline along the dura of the cribriform plate and may reach a large size before producing symptoms. We conducted a retrospective study of patients with these lesions focused on pre- and post-operative investigations for ophthalmological, personality and cognitive disturbances.

METHODS

The authors reviewed 36 patients with giant olfactory groove meningiomas surgically treated via a bifrontal approach. Ophthalmological evaluation included visual acuity, fundoscopy and visual fields while psychological evaluation included a Mini-Mental State Examination. Data was collected before, 1 and 12 months after surgery. Formal pre- and post-operative ophthalmological examinations discovered visual deficits in 55.5% of the patients. Within the first month after surgery, improvement of visual acuity and of visual field deficits was observed. In post-operative neuropsychological testing, higher mental functions showed improvement. The most frequent post-operative complication was persistent rhinorrhoea in two patients.

CONCLUSIONS

Results at longest follow up indicate that cognitive changes and visual deficits will improve in patients with giant olfactory groove meningiomas after a bifrontal approach, without additional neurological deficits.

The role of surgery when endovascular treatment is considered the first choice therapy for ruptured intracranial aneurysms

AIM

Nowadays endovascular therapy is more and more considered as first choice treatment for ruptured intracranial aneurysms. The aim of this study was to understand the impact that endovascular treatment (EVT), chosen as first therapeutic strategy, has had in the selection of ruptured intracranial aneurysms submitted to surgery at our Institution and what role neurosurgeons still play in this setting.

METHODS

From 1998 to 2002, 272 consecutive patients were treated at the Hospital of Toulouse for ruptured intracranial aneurysms: 222 by embolization and 50 by surgery. The two groups were homogeneous for sex, age and aneurysms multiplicity.

RESULTS

The patients of the surgical group had a worst clinical-radiological status at the treatment time than those treated by EVT. Clipping was performed for different reasons: 16% for failure of attempted EVT; 32% for intracranial hematoma requiring surgical evacuation; 30% for aneurysm morphology unsuitable for EVT and 22% for absence of the endovascular operator. Aneurysms of the middle cerebral artery (MCA) represented the main surgical group. The aneurysms judged unsuitable for EVT and addressed to surgery had often a complex morphology representing a challenge also for surgery. Mid-term outcome is significantly better for patients treated by EVT.

CONCLUSION

The results show that microsurgery continues to have a role in the treatment of ruptured intracranial aneurysms even when EVT is the first choice. The precarious clinical conditions of the patients submitted to surgery and the frequent complexity of their aneurysms explain their worst outcome. This would advise training dedicated vascular Neurosurgeons to guaranty a high level treatment when EVT is not possible.

Microsurgery for vestibular schwannoma after gamma knife radiosurgery

BACKGROUND

We evaluated the clinical characteristics of microsurgery for vestibular schwannoma (VS) after failed gamma knife radiosurgery (GKS).

METHOD

Twelve patients, 5 men and 7 women aged 19 to 70 years (mean 54.5 years), who underwent microsurgery after failed GKS for VS were studied retrospectively.

FINDINGS

The median interval between GKS and microsurgery was 28.8 months (range, 6.6-120 months) and 4 patients had undergone previous microsurgery. The mean volume of tumour at GKS was 6.9 cm(3) (range, 0.5-19.7 cm(3)) and the mean prescription dose to the tumour margin was 12.3 Gy. Microsurgery involved the lateral suboccipital approach in all patients. Tumour expansion involved solid enlargement in 7 patients, cystic enlargement in 3, and central necrosis in 2. Bleeding was slight in all patients except in one, probably because of the previous irradiation. Adhesion to the brain stem was severe in 7 patients. Identification of the facial nerve was easy in 5 operations and difficult in 7. Dissection of the tumour from the facial nerve was difficult in most interventions because of severe adhesions or colour change. Severe adhesions between the trigeminal nerve and the tumour was observed in 2 patients. The tumour was subtotally removed except around the internal auditory canal in most patients. Only one residual tumour increased in size and needed second GKS. The function of the facial nerve deteriorated in 3 patients, was unchanged in 7, and improved in 2. All patients had lost hearing on the affected side at the time of microsurgery.

CONCLUSIONS

Microsurgery for VS after failed GKS presents some technical difficulties. Dissection of the tumour from the facial nerve or brain stem is likely to be difficult. We recommend subtotal resection without dissection of the facial nerve and tumour, because growth of the residual tumour was rare in our series.

Excision of pituitary adenomas: randomized comparison of surgical modalities

The aim of this randomized prospective study was to compare the efficacy of endoscopic versus standard microsurgical excision of pituitary adenomas, and to evaluate the merits and demerits of each approach. Twenty patients with a pituitary adenoma were randomly divided into two groups comprising of 10 cases each. Ten cases were operated by endoscopic endonasal trans-sphenoidal approach by endoscopic rhinologist (EETSS group) and other 10 cases were excised by microsurgical endonasal trans-sphenoidal approach by a neurosurgeon (SMETSS group). In both the groups complete excision was achieved in 50% of patients (unpaired t-test, p = 1.00). In EETSS group mean operative time was 64.5 +/- 19.16 min (range 50 - 100 min). In the SMETSS group, mean operative time was 75.5 +/- 18.48 min (range 55 - 120 min; unpaired t-test, p = 0.64, statistically not significant). In the EETSS group blood loss ranged between 100 and 190 ml (mean 100 +/- 42.16 ml). In the SMETSS group blood loss ranged between 50 and 250 ml (mean loss of 120 +/- 58.69 ml; unpaired t-test, p < 0.05, statistically significant). Postoperative nasoseptal complications were more common in SMETSS group (Chi-square test, p < 0.05, statistically significant). Endoscopic approach provides a wide surgical field and broad lateral vision making easier distinction of tumour tissue: gland and gland diaphragm interface. Thus, there is less blood loss and nasoseptal complications, whereas there was no statistically significant difference in operative time and complete tumour removal.

Assessment of the anatomical relationship between the arcuate eminence and superior semicircular canal by computed tomography

The anatomical relationship between the arcuate eminence (AE) and the superior semicircular canal (SSC) was examined by computed tomography (CT) in 52 petrous bones of 26 patients. After acquiring volume data by multidetector CT, 1-mm thick oblique bone window images perpendicular to the SSC were obtained from the axial images. The distances between the AE and the SSC, and the SSC and the superior surface of the petrous bone were measured. The AE corresponded exactly with the SSC in only 2/52 petrous bones, and corresponded well in 7/52. The AE was lateral to the SSC in 25/52 cases, medial to the SSC in 6/52 cases, intersected in 3/52 cases, and was indiscernible in 9/52 cases. The distance between the SSC and the petrous surface was 0 mm in 45/52 petrous bones, 1 mm in 5/52, 2 mm in 1/52, and 3 mm in 1/52. The SSC typically does not correspond exactly with the AE, and is generally located just under the surface of the petrous bone. Planning of the middle cranial fossa approach requires location of the SSC by CT.

Acoustic neuroma (vestibular schwannoma): surgical results on 240 patients operated on dorsal decubitus position

OBJECTIVE: To evaluate the result of the surgical treatment of vestibular schwannoma (VS) operated in dorsal decubitus (mastoid position). METHOD: 240 patients with a VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7th and 8th cranial nerves was monitored during surgery and the opened internal auditory canal (IAC) was reconstructed using a vascularized dura flap, muscle and fibrin glue. RESULTS: Complete tumor removal was achieved in 99% of the cases, with a mortality of 1.6%. The facial nerve function was preserved in 85% of cases and hearing in 40% of the patients (with preoperative hearing) with tumors of up 1.5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8% and meningitis 2.9%. Venous air embolism was registered in 3% of cases; it was not associated to mortality. CONCLUSION: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low.

Tertiary resurfacing after one of the first free flaps in Europe, a reflection on 30 years of microsurgical progress

Free flaps have been used for over 30 years. During this period, improved anatomical understanding has increased donor options and available pedicle lengths, permitting safer, single-stage reconstructions with simpler anastomoses. Refinements, such as perforator flaps in particular, have greatly improved donor morbidity, recipient site cosmesis, and the ability to replace 'like with like' while retaining options for innervation. This case highlights the evolution from one of Europe's first free tissue transfers, effectively a perforator flap, through the advent of free muscle flaps to the current generation of contourable perforator flaps. Free flap transfer has become increasingly sophisticated, safer, and more predictable, yet the potential quality of reconstructive outcome has changed little.

Microvascular decompression as a treatment for cranial nerve hyperactive dysfunction--a critical view

Neurovascular compression has been postulated as a probable mechanism for a large number of cranial nerve syndromes, with trigeminal neuralgia (TGN) as the prime example. Microvascular decompression (MVD) is often cited as the procedure of choice for treatment of medically refractory TGN. Arguments against these assumptions are: MRA studies indicate that vascular contact with the trigeminal nerve is present in most healthy individuals. Treatment results of MVD in multiple sclerosis patients with TGN are almost as good (at least in the short term) as in idiopathic cases. MVD is reported to provide pain relief even in TGN patients without visible neurovascular contact . In other syndromes of cranial nerve'hyperactive dysfunction'--vertigo, tinnitus and neurogenic hypertension--the documentation is even weaker.

"Triple cross" of the hypoglossal nerve and its microsurgical impact to entrapment disorders

OBJECTIVE

Cadaveric dissections were performed to review the intracranial and extracranial course of the hypoglossal nerve. The neurological significance of a newly defined "triple cross" of the hypoglossal nerve is discussed.

MATERIALS AND METHODS

10 cadaveric heads (left and right; 20 sides) were dissected using microsurgical techniques.

RESULTS

In the cisternal segment of hypoglossal nerve, the diameter of the rostral trunk amounted to 155-680 microm (mean 435 microm), and the caudal trunk to 210-820 microm (mean 482 microm). The roots formed three trunks in 20% of the hypoglossal nerves and two trunks in the rest. As a first cross, the anterior medullary segment of the vertebral artery crossed the hypoglossal nerve roots in 14 of 20 sides (70%). As a rare variation, the vertebral artery extended medial to the nerve (25%) or between its roots (5%). The second cross was found between the descendens hypoglossus and the occipital artery (75%), sternocleidomastoid artery and vein complex (15%) and external carotid artery (10%). The third cross was shown in the submandibular triangle between the lingual hypoglossus and its drainage vein; vena committans nervus hypoglossus.

CONCLUSION

Throughout its way, the hypoglossal nerve passes over vascular structures in three crossing points which may serve as a probable cause of hypoglossal nerve entrapment disorders.

Surgically Treated Tuberculum Sellae and Diaphragm Sellae Meningiomas

OBJECTIVE:

The visual outcome in patients with tuberculum and diaphragm sellae meningiomas treated with microsurgery was evaluated. Prognostic and diagnostic values of short- and long-term postoperative visual outcome and etiology for postoperative visual deterioration are discussed with special attention.

METHODS:

Clinical data for 30 surgically treated patients with tuberculum and diaphragm sellae meningiomas were reviewed retrospectively. The mean duration of the follow-up period was 75.9 months (range, 12–151 mo). Mean tumor diameter and volume was 25.9 mm (range, 16.3–63.3 mm) and 12.4 cm3 (range, 2.3–125.6 cm3). A visual impairment score was used to assess the short-term (≤2 wk after surgery) and the long-term (&gt;6 mo after surgery) postoperative visual outcome. Various predictive factors for visual outcome were tested statistically.

RESULTS:

Complete resection was achieved in 23 out of 30 (76.7%) patients. Average preoperative, short- and long-term visual impairment scores were 48.2, 43.4, and 40.9, respectively. Favorable visual outcome was achieved in 80% of patients in the short term and 70% in the long term. Short-term postoperative aggravation of visual function was an ominous sign of further aggravation or at least of little hope for recovery, whereas there was a tendency to improve in the long term if short-term postoperative visual function showed favorable outcome. Recurrence or regrowth of tumor fully was responsible for late deterioration of visual function. No significant prognostic factor for visual outcome could be found.

CONCLUSION:

Short-term postoperative visual outcome was a strong indicator of permanent visual outcome after surgery for tuberculum sellae and diaphragm sellae meningiomas.

Intraneural ganglion cyst of the tibial nerve

Intraneural ganglion cyst of the tibial nerve is very rare. To date, only 5 cases of this entity in the popliteal fossa have been reported. We report a new case and review the previously reported cases. A 40-year-old man experienced a mild vague pain in the medial half of his right foot for 3 years. Magnetic resonance imaging scan demonstrated a soft-tissue mass along the right tibial nerve. At surgery, an intraneural ganglion cyst was evacuated. After 12 months, the patient was pain-free with no signs of recurrence. Trauma might be a contributing factor to the development of intraneural ganglion cysts. Application of microsurgical techniques is encouraged.

Patient Outcomes After Vestibular Schwannoma Management: a Prospective Comparison of Microsurgical Resection and Stereotactic Radiosurgery

OBJECTIVE

The best management for patients with small- to medium-sized vestibular schwannomas (VS) is controversial.

METHODS

: A prospective cohort study of 82 patients with unilateral, unoperated VS less than 3 cm undergoing surgical resection (n = 36) or radiosurgery (n = 46). Patients undergoing resection were younger (48.2 yr versus 53.9 yr, P = 0.03). The groups were similar with regard to hearing loss, associated symptoms, and tumor size. The mean follow-up period was 42 months (range, 12-62 mo).

RESULTS

Normal facial movement and preservation of serviceable hearing was more frequent in the radiosurgical group at 3 months (P < 0.001), 1 year (P < 0.001), and at the last follow-up examination (P < 0.01) compared with the surgical resection group. Patients undergoing surgical resection had a significant decline in the following subscales of the Health Status Questionnaire 3 months after surgery: physical functioning (P = 0.006), role-physical (P < 0.001), energy/fatigue (P = 0.02), and overall physical component (P = 0.004). Patients in the surgical resection group continued to have a significant decline in the physical functioning (P = 0.04) and bodily pain (P = 0.04) subscales at 1 year and in bodily pain (P = 0.02) at the last follow-up examination. The radiosurgical group had no decline on any component of the Health Status Questionnaire after the procedure. The radiosurgical group had lower mean Dizziness Handicap Inventory scores (16.5 versus 8.4, P = 0.02) at the last follow-up examination. There was no difference in tumor control (100 versus 96%, P = 0.50).

CONCLUSION

Early outcomes were better for VS patients undergoing stereotactic radiosurgery compared with surgical resection (Level 2 evidence). Unless long-term follow-up evaluation shows frequent tumor progression at currently used radiation doses, radiosurgery should be considered the best management strategy for the majority of VS patients.

Guidelines for the optimization of microsurgery in atherosclerotic patients

We review the pathogenesis of atherosclerosis and the issues that must be taken into consideration when performing microsurgery in atherosclerotic patients. Atherosclerosis is a systemic disease, and may affect the success of microsurgery. Atherosclerotic patients have a tendency toward thrombosis, because the nature of the arteries is changed. Such patients are usually old and have additional medical problems. To increase the success rate of microsurgery in atherosclerotic patients, special precautions should be considered. Patients must be evaluated properly for the suitability of microsurgery. The microsurgical technique requires a meticulous approach, and various technical tricks can be used to avoid thrombosis. Recipient-vessel selection, anastomotic technique, and the use of vein grafts are all important issues. Prophylactic anticoagulation is recommended in severely atherosclerotic patients. Close monitoring of the patient and flap is necessary after the operation, as with routine microvascular free-tissue transfers. We conclude that atherosclerosis is not a contraindication for microsurgery. If the microsurgeon knows how to deal with the difficulties in atherosclerotic patients, microsurgery can be performed safely.

[Microsurgical vasovasostomy at the Erasmus MC, 1998-2002: results and predictive factors]

OBJECTIVE

To determine the results ofmicrosurgical vasovasostomy procedures with special emphasis on the technical aspects and predictive factors for successful procedures.

DESIGN

Descriptive.

METHOD

In 1998-2002, 217 vasovasostomy procedures were performed in an outpatients' clinic setting at the Erasmus MC, Rotterdam, The Netherlands.

RESULTS

Refertilisation was successful in 77% of men and 42% of couples reported a spontaneous pregnancy within one year. The most important predictive factors for a successful outcome were the interval between vasectomy and reversal and the age of the partner. Patency rates were 89% and 62% when the interval was < 5 years and > 15 years, respectively. Rates of spontaneous pregnancy were 56% and 21%, respectively. These reductions in rates of patency and pregnancy were attributed primarily to epididymal dysfunction and an increasing interval between vasectomy and reversal. Only 20% of men with a partner aged > 35 years reported spontaneous pregnancies. The risk of secondary epididymal obstruction was 25% after an interval of > 10 years. For these cases, a vasoepididymostomy is needed to achieve patency.

A fully automated calibration method for an optical see-through head-mounted operating microscope with variable zoom and focus

Ever since the development of the first applications in image-guided therapy (IGT), the use of head-mounted displays (HMDs) was considered an important extension of existing IGT technologies. Several approaches to utilizing HMDs and modified medical devices for augmented reality (AR) visualization were implemented. These approaches include video-see through systems, semitransparent mirrors, modified endoscopes, and modified operating microscopes. Common to all these devices is the fact that a precise calibration between the display and three-dimensional coordinates in the patient's frame of reference is compulsory. In optical see-through devices based on complex optical systems such as operating microscopes or operating binoculars-as in the case of the system presented in this paper-this procedure can become increasingly difficult since precise camera calibration for every focus and zoom position is required. We present a method for fully automatic calibration of the operating binocular Varioscope M5 AR for the full range of zoom and focus settings available. Our method uses a special calibration pattern, a linear guide driven by a stepping motor, and special calibration software. The overlay error in the calibration plane was found to be 0.14-0.91 mm, which is less than 1% of the field of view. Using the motorized calibration rig as presented in the paper, we were also able to assess the dynamic latency when viewing augmentation graphics on a mobile target; spatial displacement due to latency was found to be in the range of 1.1-2.8 mm maximum, the disparity between the true object and its computed overlay represented latency of 0.1 s. We conclude that the automatic calibration method presented in this paper is sufficient in terms of accuracy and time requirements for standard uses of optical see-through systems in a clinical environment.

Outcome determinants of pterional surgery for tuberculum sellae meningiomas

BACKGROUND

Current literature on tuberculum sellae meningiomas is very heterogenous due to wide variation in nomenclature, diagnostic and operative techniques. The aim of this study is specifically to analyze the results of pterional craniotomy for tuberculum sellae meningiomas. A homogenous cohort of 42 consecutively operated tuberculum sellae meningioma cases are reviewed with special emphasis on the effects of pterional microsurgery on visual outcome.

METHODS

This is a retrospective clinical analysis. 42 consecutive patients operated upon during the period of 15 years in a single institution using standard imaging protocols and pterional microsurgery are presented and effect of various variables on visual outcome analysed.

FINDINGS

81% of the patients presented with visual symptoms. The mean duration of symptoms was 12 months. Tumour volumes ranged from 7.5 to 210 mm(3). A right sided pterional microsurgery was used in all patients. Complete resection rate was 81%. Vision improved in 58%, worsened in 14%. Non-visual morbidity was 7.1% and mortality was 2.4%. The follow up period of patients ranged from 3 to 192 months (median: 30 months). The mean was 37.5 months (SD = +/-36.7 months) and a recurrence rate of 2.4% was observed.

CONCLUSIONS

A standard pterional craniotomy using microsurgical technique provides the necessary exposure enabling total removal while keeping the complications to a minimum. Upon analysis of our findings we found that patient age of more than 60, duration of visual symptoms longer than 1 year, severe visual symptomatology, predominantly vertical growth, presence of significant peri-tumoural oedema, absence of an intact arachnoid plane and subtotal removal were correlated with a dismal visual outcome.