Complete endoscopic removal of colloid cyst using a nitinol basket retriever

Specialised Surgical Instruments for Endoscopic and Endoscope-Assisted Neurosurgery: A Systematic Review of Safety, Efficacy and Usability

While there have been great strides in endoscopic and endoscope-assisted neurosurgical approaches, particularly in the treatment of deep-sited brain and skull base tumours, the greatest technical barrier to their adoption has been the availability of suitable surgical instruments. This systematic review seeks to identify specialised instruments for these approaches and evaluate their safety, efficacy and usability. Conducted in accordance with the PRISMA guidelines, Medline, Embase, CENTRAL, SCOPUS and Web of Science were searched. Original research studies that reported the use of specialised mechanical instruments that manipulate tissue in human patients, cadavers or surgical models were included. The results identified 50 specialised instruments over 62 studies. Objective measures of safety were reported in 32 out of 62 studies, and 20 reported objective measures of efficacy. Instruments were broadly safe and effective with one instrument malfunction noted. Measures of usability were reported in 15 studies, with seven reporting on ergonomics and eight on the instruments learning curve. Instruments with reports on usability were generally considered to be ergonomic, though learning curve was often considered a disadvantage. Comparisons to standard instruments were made in eight studies and were generally favourable. While there are many specialised instruments for endoscopic and endoscope-assisted neurosurgery available, the evidence for their safety, efficacy and usability is limited with non-standardised reporting and few comparative studies to standard instruments. Future innovation should be tailored to unmet clinical needs, and evaluation guided by structured development processes.

Extruded contents of colloid cysts after endoscopic removal

OBJECTIVE

Mineralized or desiccated colloid cysts pose some unique challenges to endoscopic removal. The extrusion of the solid matrix into the intraventricular compartment has not been previously reported and, as such, no guidance exists regarding its predilection, prevention, and fate.

METHODS

Postoperative imaging studies in a registry of patients undergoing endoscopic removal of colloid cyst were reviewed to detect any solid matrix within the ventricular compartment. Preoperative images and operative notes were used to determine if any features were predictive. Serial postoperative images and clinical notes were used to characterize the implications of these findings.

RESULTS

From a review of 94 patients, 10 (10.6%) patients had evidence of an extruded intraventricular solid fragment (median follow-up 4 months; range 0.5–115 months). Of the evaluable patients, 7 of 9 patients had T1-weighted hyperintense and T2-weighted hypointense cysts on preoperative scans. Seventy-eight percent of the extrusions were on the same side as the endoscopic entry. Three patients demonstrated early fragment migration, but not after 8 months of radiological follow-up. All evaluable patients demonstrated improvement in their hydrocephalus, and none suffered a complication attributable to the intraventricular extruded fragments.

CONCLUSIONS

Intraventricular extruded colloid fragments can occur after endoscopic resection, with the possible risk demonstrated as cyst hypointensity on preoperative T2-weighted images. The finding does not seem to result in any clinical morbidity, and radiographic involution is the rule. Migratory capacity, however, does exist and justifies a more frequent imaging surveillance schedule and consideration for removal.

Single port microsurgical technique for excision of third ventricular colloid cysts

INTRODUCTION

Colloid cysts are benign space-occupying lesions that account for 0.5-1.0% of brain tumors and arise from the velum interpositum or the choroid plexus of the third ventricle.

MATERIAL AND METHODS

We are describing a modified surgical technique that combines the positive attributes of being minimalistic, while retaining the effectiveness of microsurgery. In all 20 consecutive symptomatic patients with a preoperative magnetic resonance imaging (MRI) diagnosis of colloid cyst who came to the senior author between 2008 and 2011 were included in the study. The patient was kept supine with the head positioned neutrally in the sagittal plane and neck flexed at 20°. The tube of a 5 ml plastic syringe having an external diameter of 13 mm and an internal diameter of 12.6 mm was cut toward the nozzle end to the appropriate length depending upon the cortical thickness measured on the preoperative MRI.

RESULTS

The average operative time was around 90 min with maximum of 120 min. None of the patients had seizures preoperatively or postoperatively and in all cases antiepileptic medication could be stopped after 3-6 month of surgery. Two patients had short-term memory impairment which returned to near normal by 1-year following surgery.

CONCLUSION

A volume of 5 ml plastic syringe port technique decreases the operative morbidity and operative time. The wider corridor of working makes the simultaneously maneuverability of two surgical instruments feasible enhancing safety and completeness of excision.

Endoscopic removal of an intraventricular primitive neuroectodermal tumor: retrieval of a free-floating fragment using a urological basket retriever

The endoscopic resection of intraventricular tumors represents a unique challenge to the neurological surgeon. These neoplasms are invested deep within the brain parenchyma and are situated among neurologically vital structures. Additionally, the cerebrospinal fluid system presents a dynamic pathway for resected tumors to be mobilized and entrapped in other regions of the brain. In 2011, the authors treated a 3-year-old girl with a third ventricular mass identified on stereotactic brain biopsy as a WHO Grade IV CNS primitive neuroectodermal tumor. After successful neoadjuvant chemotherapy, endoscopic resection was performed. Despite successful resection of the tumor, the operation was complicated by mobilization of the resected tumor and entrapment in the atrial horn of the lateral ventricle. Using a urological stone basket retriever, the authors were able to retrieve the intact tumor without additional complications. The flexibility afforded by the nitinol urological stone basket was useful in the endoscopic removal of a free-floating intraventricular tumor. This device may prove to be useful for other practitioners performing these complicated intraventricular resections.