Interactive image-guided transcallosal microsurgery for anterior third ventricular cysts.

Although the treatment of colloid cysts remains controversial, high viscosity and small volume are poor prognostic indicators for successful burr hole aspiration and cortical incision via craniotomy may be associated with postoperative epilepsy. The anterior transcallosal approach provides a direct and adequate pathway to the lateral ventricles, where the foramen of Monro serves as a natural entrance into the anterior third ventricle, especially when the foramen is dilated by a lesion. When the midsuperior portion of the IIIrd ventricle cannot be reached, the interforniceal or the subchoroidal exposures have been advocated. Stereotactic techniques contribute to a minimal invasive approach and reduce morbidity. Nine patients harbouring anterior third ventricular cysts (seven colloids and two intrinsic craniopharyngiomas) underwent anterior transcallosal microsurgical excision assisted by an interactive infrared-based image guided system (EasyGuide, Neuro, Philips). There were 4 men and 5 women ranging in age from 15 to 42 years (mean 28.5). Transcallosal transforaminal (5 cases) or interforniceal (4 cases) approaches allowed total excision in eight patients and subtotal in one. Postoperative morbidity included a case of transient hemiparesis and a case of transient short-term memory disturbances; both resolved in the first months. Mortality was zero. Particular advantages of the method were accurate trajectory and position of callosotomy incision determination, visualisation and avoidance of superior saggital sinus, retraction of bridging veins and the often variable pericallosal arteries, spatial orientation within the ventricular system, and identification of the periventricular anatomical structures.

Clinical validation of true frameless stereotactic biopsy: analysis of the first 125 consecutive cases.

OBJECTIVE: A lockable guide device, adjustable for positioning, was used to obtain samples for tissue analysis during brain biopsy procedures performed using an interactive image guidance system. Clinical validation of this technique, which was developed for true frameless stereotactic biopsies, and analyses of the histological yield, complication rate, and patient demographic characteristics for a large series of frameless stereotactic biopsies were the purposes of this study. METHODS: Demographic, radiological, surgical, and clinical data were prospectively collected for a series of 125 frameless stereotactic biopsies performed using the technique described in detail previously. RESULTS: Eighty-six procedures were magnetic resonance imaging-directed and 39 were computed tomography-directed. The mean diameter of the biopsied lesions was 36 mm, and the mean distance from the skin was 35.8 mm. Sixteen percent of the patients harbored multiple lesions, and 5.6% of the biopsied lesions were infratentorial. The mean operative time (including the entire anesthetic time) was 1.5 hours. The smear examination findings were corroborated by conclusive histological results in 96% of the cases, and definitive positive diagnoses were obtained in 122 cases (97.6%). Ten patients experienced surgical complications, but the sustained morbidity rate was 2.4% (including the death of a patient who was in critical clinical condition preoperatively and who died 2 mo later as a result of a chest infection; mortality rate, 0.8%). CONCLUSION: This true frameless stereotactic biopsy technique was associated with low morbidity and mortality rates and an excellent diagnostic yield, with overall results at least as good as those observed for frame-based stereotaxy. The excellent accuracy results demonstrated previously and statistically significant reductions in operative time, as well as improved image presentation, target selection, and simplicity, support the use of this frameless stereotactic technique in preference to frame-based biopsy techniques.

Clinical utility and cost-effectiveness of interactive image-guided craniotomy: clinical comparison between conventional and image-guided meningioma surgery.

OBJECTIVE: Although interactive image guidance has been determined to be an increasingly important and reliable tool in contemporary neurosurgery, the clinical results and cost-effectiveness of the use of these systems, compared with conventional techniques, remain understudied. The aim of this study was to investigate the possible benefits of image-guided craniotomies to treat meningiomas, in terms of hospital stays, surgical complications, and, consequently, cost-effectiveness, compared with the results of standard surgery (SS). METHODS: During a 3.5-year period, 100 patients were surgically treated for meningiomas using image-guided surgery (IGS) with neuronavigation assistance and 170 were surgically treated using SS. From the consecutive series of the 100 IGS cases, it was possible to statistically match 50 (in terms of the demographic data, the location and size of the tumor, and the experience of the surgeon) with 50 SS cases. The clinical data were collected prospectively for the IGS group and retrospectively for the SS group. RESULTS: The anesthetic (operation) times were similar for the two groups, although surgical times were shorter for the IGS group (P = 0.02). Blood loss during surgery was less for the IGS group (although not statistically significantly, P > 0.05), but more SS cases required transfusions (P = 0.03). The mean intensive therapy unit stay was 1.7 days for the SS group and 1 day for the IGS group (P = 0.12); the mean hospital stays were 13.5 and 8.5 days, respectively (P = 0.017). Severe complications (permanent or requiring additional surgical procedures) were encountered in 14% of the cases in the SS group and 6% of the cases in the IGS group (P = 0.019), whereas the rates of minor complications (resolved within 30 d without further surgery) were similar (8 and 10%, respectively). The most common problems for the control group were postoperative hematomas (n = 3), which required urgent surgery in two cases; intractable postoperative swelling was treated by lobectomy in another case. In the IGS group, the two severe complications included one case of an infected bone flap and one case of a new permanent neurological deficit. The mean cost per patient was approximately 20% higher for SS than for IGS. CONCLUSION: Although this was not a randomized study, the analysis of these results strongly suggests a positive effect of neuronavigation on the complication rate and thus on intensive care unit and hospital stays, with attendant financial implications.

Experience with neurocysticercosis in the UK: correct diagnosis and neurosurgical management of the small enhancing brain lesion.

Neurocysticercosis is a major cause of epilepsy and other neurological morbidity in endemic areas of the world but is exceptionally rare in the West. We have recently had experience of eight patients with this condition, seven presenting with epilepsy and single or multiple small, enhancing parenchymal lesions and one with hydrocephalus caused by a midbrain lesion. One lesion was stereotactically excised after it persisted, but in five other cases spontaneous cyst resolution was observed during expectant management with anticonvulsants. Two patients with multiple lesions were referred to us for further management but were free of active infection. Recent studies show that neurocysticercosis may often be diagnosed based upon the clinical, epidemiological and radiological features. Spontaneous cyst resolution is to be expected in this condition and suspected patients should be carefully observed and surgery avoided. We believe that this disease presents more commonly than has been appreciated in the UK and propose a protocol for management.

Precise cannulation of the foramen ovale in trigeminal neuralgia complicating osteogenesis imperfecta with basilar invagination: technical case report.

OBJECTIVE AND IMPORTANCE: Trigeminal neuralgia is a rare feature of basilar invagination, which is itself a complication of osteochondrodysplastic disorders. Microvascular decompression is an unattractive option in medically refractory cases. The conventional percutaneous approach to the trigeminal ganglion is anatomically impossible because the foramen ovale points inferiorly and posteromedially. We report a new technique for image-guided trigeminal injection in a patient with basilar invagination complicating osteogenesis imperfecta. CLINICAL PRESENTATION: A 26-year-old woman with osteogenesis imperfecta presented with a 3-year history of typical left maxillary division trigeminal neuralgia, which was poorly controlled by carbamazepine at the maximum tolerated dose. She had obvious cranial deformities, left optic atrophy, delayed left eye closure, tongue atrophy, but normal facial sensation and corneal reflexes. A computed tomographic scan and magnetic resonance imaging confirmed severe basilar invagination. TECHNIQUE: Frameless stereotactic glycerol injection of the left trigeminal ganglion was performed under general anesthesia using the infrared-based EasyGuide Neuro system (Philips Medical Systems, Best, The Netherlands) with magnetic resonance imaging and computed tomographic registration. The displaced and distorted left foramen ovale was cannulated via a true frameless stereotactic method with the trajectory determined by virtual pointer elongation. The needle placement was confirmed with injection of contrast medium into the trigeminal cistern. The path needed to enter the foramen traversed the right cheek, soft palate, and left tonsil. The patient went home pain-free with a preserved corneal reflex and no complications. CONCLUSION: Frameless stereotaxy allows customization to individual patient anatomy and may be adapted to a variety of percutaneous procedures used in areas where the anatomy is complex.

Paired colloid cysts of the third and lateral ventricles.

We report the case of a man of aged 27 years who presented with obstructive hydrocephalus caused by a colloid cyst of the third ventricle. He was found to have an additional and larger colloid cyst lying adjacent to it, but within the lateral ventricle. The contents of the two cysts were of different consistency. We have been able to find only one previous report of more than one colloid cyst occurring in the same patient and none where one of the cysts lay within the lateral ventricle.

The EASI project--improving the effectiveness and quality of image-guided surgery.

In recent years, advances in computer technology and a significant increase in the accuracy of medical imaging have made it possible to develop systems that can assist the clinician in diagnosis, planning, and treatment. This paper deals with an area that is generally referred to as computer-assisted surgery, image-directed surgery, or image-guided surgery. We report the research, development, and clinical validation performed since January 1996 in the European Applications in Surgical Interventions (EASI) project, which is funded by the European Commission in their "4th Framework Telematics Applications for Health" program. The goal of this project is the improvement of the effectiveness and quality of image-guided neurosurgery of the brain and image-guided vascular surgery of abdominal aortic aneurysms, while at the same time reducing patient risks and overall cost. We have developed advanced prototype systems for preoperative surgical planning and intraoperative surgical navigation, and we have extensively clinically validated these systems. The prototype systems and the clinical validation results are described in this paper.

Delayed surgery for ruptured intracranial aneurysms: a reappraisal.

Delayed aneurysm surgery, once standard practice, is now followed by only a minority of neurosurgeons. We analysed the outcome of such a policy in 400 consecutive patients with ruptured aneurysms treated over a 14-year period. Despite an 'open door' admissions policy, admitting all patients immediately on referral, only 56% arrived within 24 h of the ictus (69% within 72 h). Surgery was generally delayed for 8-10 days in patients in Grades 1 and 2; for higher grade patients often for longer until their condition was stable. Two-hundred-and-eighty-seven patients (72%) underwent surgery, 93% on day 8 or later (78% on day 11 or later). Outcome was assessed at 1 year. For all patients 68% were in Glasgow Outcome Scale Grade 1, while 26% had died. Of the operated patients 88% were in GOS grade 1, while 5% had died (30-day surgical mortality was 3.5%). Fifty-one patients (12.8%) rebled, 30 in the first 10 days. Rebleeding was distributed evenly in time over the first 2 weeks. Eighty-four patients experienced non-haemorrhagic deterioration (NHD) all but 3 within 10 days. NHD peaked at days 4-9. Thirty-three patients died of rebleeding and 16 of NHD, but only 12 of the patients who died from rebleeding were fit for operation at anytime and might have been considered for early surgery. Two of these patients died so soon after admission that surgery could not have been performed leaving 10 patients who might have been saved by early surgery. We review the theoretical advantages of delayed as against early surgery and conclude that it is doubtful whether the timing of surgery has any significant effect on management outcome in line with the conclusions of the Cooperative Study.

Self-trephination of the skull with an electric power drill.

There is extensive archaeological evidence of the practice of trephination of the skull in many ancient cultures in different parts of the world. We report a case of self-trephination of the skull by a patient using an electrical power drill subsequently requiring neurosurgical intervention.