Microanatomical study on paramedian supracerebellar infratentorial keyhole approach

Objective To design a paramedian supracerebelalr infratentorial keyhole approach by applying the keyhole conception and explore its feasibility. The keyhole approach is imitated and microanatomical structures are observed,which could be reference of this approach in clinical use. Methods The paramedian

Trans-eyebrow supraorbital endoscope-assisted keyhole approach to suprasellar meningioma in pediatric patient:case report and literature review

Background:Meningiomas are rather uncommon tumors in the pediatric population,differing significantly from those found in adults by their atypical location,higher rate of more malignant types,consequently higher risk of recurrence and a less favorable outcome.Even in children,suprasellar meningiomas without dural matrix are rare findings mimicking more common suprasellar lesions.Case presentation:Here we describe a case of a 12-year-old girl who presented with a rapidly progressing chiasmal syndrome and was diagnosed by MRI with an unusual suprasellar tumor that could not fit the diagnoses expected in a case of a parasellar mass in a child,similar to a craniopharyngioma or optic pathway glioma.After multiple clinical investigations,the tumor etiology was still unclear,so the preferred option of treatment was surgical resection.An endoscope-assisted gross total resection through a supraorbital keyhole approach was performed uneventfully,with total vision recovery in a short time.Benign meningiomas located in the skull base without dural attachment appear to be rare,even in pediatric patients.Conclusion:Differential diagnoses of suprasellar and para sellar tumor lesions in pediatric patients can be confusing.There are peculiar features of pediatric tumor diseases that should be considered while working out the management strategy.The main principle of meningioma treatment is the highest possible extent of resection minimally affecting the quality of life.

Minimally invasive keyhole approaches for removal of tumors of the third ventricle

Background In recent years, keyhole microsurgery has become an important subject of modern minimally invasive neurosurgery. In this study, minimally invasive techniques avoiding unnecessary tissue injuries were applied to refine traditional approaches for the removal of third ventricular tumors within a limited operative filed. Methods Individualized keyhole approaches were designed according to the characteristics of third ventricular tumors and their growth patterns. A series of keyhole approaches such as supraorbital subfrontal approach, infratentorial supracerebellar approach, interhemispheric transcallosal approach, pterional approach were taken to enter the third ventricle anteriorly, posteriorly, superiorly or laterally, respectively. A total of 34 removed tumors in or extended into the third ventricle included 11 craniopharyngiomas, 10 pituitary adenomas, 2 pinealomas, 1 cholesteatoma, 3 germinomas, and 7 gliomas. Results Total tumor resection was done in 27 （79.4%） of the patients, and subtotal resection in 7 patients （20.6%）. Residual tumor was due to tight adherence of germinoma to the vein of Galen （1 patient）, craniopharyngioma to the pituitary stalk （3）, supratentorial extension of pineal region gliomas （1）, suprasellar extension of gliomas （1） and giant pituitary adenoma （1）. Complications such as brain contusion, postoperative hemorrhage and infection were not associated with keyhole approaches. Extended incision or enlarged bone flap was not made because of episode during operation or inadequate exposure. Conclusions Keyhole approaches are safe, effective and minimally invasive in the surgical treatment of tumors deeply seated in the third ventricle. Individualized keyhole approach ensures a successful treatment. Tumors in the upper middle part of the third ventricle can be exposed by the interhemispheric transcallosal keyhole approach. Tumors of the posterior third ventricle may be well exposed by the infratentorial supracerebellar keyhole approach. Tumors of the anterior third ventricle can be entered by either a supraorbital subfrontal keyhole approach or a pterional keyhole approach.

Anatomical study of endoscope-assisted far lateral keyhole approach to the ventral craniocervical region with neuronavigational guidance

Background Image-guided neurosurgery, endoscopic-assisted neurosurgery and the keyhole approach are three important parts of minimally invasive neurosurgery and have played a significant role in treating skull base lesions. This study aimed to investigate the potential usefulness of coupling of the endoscope with the far lateral keyhole approach and image guidance at the ventral craniocervical junction in a cadaver model. Methods We simulated far lateral keyhole approach bilaterally in five cadaveric head specimens （10 cranial hemispheres）. Computed tomography-based image guidance was used for intraoperative navigation and for quantitative measurements. Skull base structures were observed using both an operating microscope and a rigid endoscope. The jugular tubercle and one-third of the occipital condyle were then drilled, and all specimens were observed under the microscope again. We measured and compared the exposure of the petroclivus area provided by the endoscope and by the operating microscope. Statistical analysis was performed by analysis of variance followed by the Student-Newman-Keuls test. Results With endoscope assistance and image guidance, it was possible to observe the deep ventral craniocervical junction structures through three nerve gaps （among facial-acoustical nerves and the lower cranial nerves） and structures normally obstructed by the jugular tubercle and occipital condyle in the far lateral keyhole approach. The surgical area exposed in the petroclival region was significantly improved using the 0° endoscope （1147.80 mm2） compared with the operating microscope （（756.28±50.73） mm2）. The far lateral retrocondylar keyhole approach, using both 0° and 30° endoscopes, provided an exposure area （（1147.80±159.57） mm2 and （1409.94±155.18） mm2, respectively） greater than that of the far lateral transcondylar transtubercular keyhole approach （（1066.26±165.06） mm2） （P 〈0.05）. Conclusions With the aid of the endoscope and image guidance, it is possible to approach the ventral craniocervical junction with the far lateral keyhole approach. The use of an angled-lens endoscope can significantly improve the exposure of the petroclival region without drilling the jugular tubercle and occipital condyle.

Quantification of the presigmoid transpetrosal keyhole approach to petroclival region

Background Despite the presigmoid transpetrosal approach has been used by different researchers in various ways, the surgical injury rate remains high. Applying a minimally invasive keyhole idea, we devised a presigmoid transpetrosal keyhole approach （PTKA）, classified and quantitatively assessed their approach to the petroclival area on a cadaver model by using a neuronavigation system. Methods The presigmoid transpetrosal keyhole approach was divided into four increasingly morbidity-producing steps： retrolabyrinthine, partial labyrinthectomy with petrous apicectomy, translabyrinthine and transcochlear keyhole approaches. Six latex-injected cadaveric heads （twelve sides） underwent dissection in which a neuronavigation system was used. An area of exposure 10 cm superficial to a central target （working area） was calculated. The area of clival exposure with each subsequent dissection was also calculated. Results The retrolabyrinthine keyhole approach （RLK） spares hearing and facial function in theory but provides for only a small window of upper clival exposure. The view afforded by partial labyrinthectomy with petrous apicectomy keyhole approach （PLPAK） provides for up to four times this exposure. The translabyrinthine keyhole approach （TLK） and transcochlear keyhole approach （TCK）, although producing more morbidity, add little in terms of a larger petroclival window. However, with each step, the surgical freedom for manipulation of instruments increases. Conclusions The presigmoid transpetrosal keyhole approach to the petroclival area is feasible and useful. The RLK has relatively limited utility. For lesions without bone invasion, the PLPAK provides a much more versatile exposure with an excellent chance of hearing and facial nerve preservation. The TLK provides for greater versatility in treating lesions but clival exposure is not greatly enhanced. The TCK adds little in terms of intradural exposure but should be reserved for cases in which access to the petrous carotid artery is necessary.

The supraorbital keyhole approach with eyebrow incisions for treating lesions in the anterior fossa and sellar region

Background Keyhole surgery has developed since the 1990s as a less invasive therapeutic strategy for intracranial lesions, initially for the treatment of intracranial aneurysms. The purpose of this study was to describe and evaluate the results of surgical treatment of lesions in the anterior fossa and sellar region via a supraorbital keyhole approach using eyebrow incisions. Methods Between April 1994 and July 2003, 54 patients with lesions in the anterior fossa and sellar region were operated on via the supraorbital keyhole approach. The surgical results were studied retrospectively and compared with that of patients with lesions at the same locations but treated via a conventional subfrontal approach.Results No significant difference in curative effect was found between the conventional subfrontal approach and the supraorbital keyhole approach. However, the supraorbital approach required a much smaller skin incision, causing less surgical trauma, while achieving excellent surgical exposure and good recovery. Conclusion The supraorbital keyhole approach using an eyebrow incision is safe, effective, and both suitable and convenient for treating lesions in the anterior fossa and sellar region, with almost no adverse consequences on the facial features of patients.

Minimally invasive keyhole techniques for resection of giant intracranial tumors

Background:While keyhole neurosurgery is increasingly utilized in the operating room,there are few reports regarding the use of keyhole techniques to resect giant intracranial tumors.The feasibility and technique of that were discussed in this paper.Methods:We retrospectively reviewed 95 consecutive patients who were admitted to our service between February 2012 and September 2017 with a maximum intracranial tumor diameter>5 cm.Keyhole approaches were used to resect these tumors in each case,including supraorbital,subtemporal,suboccipital,retromastoid,frontal,temporal,occipital,parietal,pterional,a combined temporo-parietal keyhole approach,and an approach via the longitudinal fissure.Results:We achieved gross total resection in 68/95 cases(71.6%)and subtotal resection in 27/95 cases(28.4%).No surgical death or severe disabilities such as coma and limb dyskinesia occurred following surgery.At the time of discharge,8 patients had complications related to impaired cranial nerve function.In addition,2 patients developed hydrocephalus requiring ventriculo-peritoneal shunt placement,and 4 patients developed a postoperative CSF leak requiring surgical intervention.Conclusion:With meticulous design and reasonable selection,resection of giant intracranial tumors utilizing minimally invasive keyhole approaches can be done safely with satisfactory surgical outcomes.