Intradural Resection Research Articles

Intraoperative ultrasonography in microsurgical resection of vestibular schwannomas via retrosigmoid approach: surgical technique and proof-of-concept illustrative case series.

Intraoperative ultrasonography (ioUS) is an established tool for the real-time intraoperative orientation and resection control in intra-axial oncological neurosurgery. Conversely, reports about its implementation in the resection of vestibular schwannomas (VS) are scarce. The aim of this study is to describe the role of ioUS in microsurgical resection of VS. ioUS (Craniotomy Transducer N13C5, BK5000, B Freq 8MHz, BK Medical, Burlington, MA, USA) is integrated into the surgical workflow according to a 4-step protocol (transdural preresection, intradural debulking control, intradural resection control, transdural postclosure). Illustrative cases of patients undergoing VS resection through a retrosigmoid approach with the use of ioUS are showed to illustrate advantages and pitfalls of the technique. ioUS allows clear transdural identification of the VS and its relationships with surgically relevant structures of the posterior fossa and of the cerebellopontine cistern prior to dural opening. Intradural ioUS reliably estimates the extent of tumor debulking, thereby helping in the choice of the right moment to start peripheral preparation and in the optimization of the extent of resection in those cases where subtotal resection is the ultimate goal of surgery. Transdural postclosure ioUS accurately depicts surgical situs. ioUS is a cost-effective, safe, and easy-to-use intraoperative adjunctive tool that can provide a significant assistance during VS surgery. It can potentially improve patient safety and reduce complication rates. Its efficacy on clinical outcomes, operative time, and complication rate should be validated in further studies.

LGG-56. Surgical management of pre-chiasmatic intraorbital optic nerve gliomas in children after loss of visual function – Resection from bulbus to chiasm

INTRODUCTION: Optic pathway gliomas (OPG) in children carry significant morbidity and therapeutic challenges. The subgroup of pre-chiasmatic gliomas manifest with exopthalmus are a subgroup where, after blindness has occurred, an intraorbital and intradural resection is a curative option. We present a two-center cohort using two different surgical approaches and describe indication, technique, and long term surgical outcome. METHODS: A retrospective analysis in both centers was performed to included patients < 18 years at diagnosis with a pre-chiasmatic intra-orbital glioma, in whom a resection from the bulb to the chiasm was performed. RESULTS: 11 patients were included. 4 had NF1. Mean age at surgery was 7.0 years. Interval between diagnosis and surgery was 1-74 (median 10) months. Two had prior chemotherapy, one radiation, one both, one prior intraorbital surgery. In all 5 progression occurred. Indications for surgery were exophthalmos, pain, tumor progression or a combination. 8 patients (Group A) underwent an extradural trans-orbital-roof approach to resect intra-orbital tumour including the optic canal part plus intradural pre-chiasmatic resection. In 3 patients (Group B) a combined supra-orbital mini-craniotomy plus orbital frame osteotomy was used for intraorbital tumour-resection, excluding the optic canal part, plus intradural pre-chiasmatic resection. GTR was achieved in 7/8 of Group A and none had a recurrence (mean-FU 42 month). One residual behind the bulbus showed progression, treated by chemotherapy. All residuals in Group B were remnants of the optic nerve within optic canal remained stable (mean FU 11.8 months). No patient had a chiasmatic functional affection or permanent oculomotor deficits. Two after prior radiotherapy developed slight enophthalmos. CONCLUSION: In these selected patients surgical resection from bulb to chiasm (± removal of optic canal tumor) is safe without long-term sequela and with excellent cosmetic result. Surgery removes immediately exophthalmos and provides an effective long-term tumor control. It should be considered therapy of choice.

Surgical Management of Pre-Chiasmatic Intraorbital Optic Nerve Gliomas in Children after Loss of Visual Function-Resection from Bulbus to Chiasm.

Optic pathway gliomas in children carry significant morbidity and therapeutic challenges. For the subgroup of pre-chiasmatic gliomas, intraorbital and intradural resection is a curative option after blindness. We present a two-center cohort using different surgical approaches. A retrospective analysis was performed, including 10 children. Mean age at surgery was 6.8 years. Interval between diagnosis and surgery was 1–74 (mean 24 ± 5.5, median 10) months. Indications for surgery were exophthalmos, pain, tumor progression, or a combination. Eight patients underwent an extradural trans-orbital-roof approach to resect the intra-orbital tumor, including the optic canal part plus intradural pre-chiasmatic resection. Gross total resection was achieved in 7/8, and none had a recurrence. One residual behind the bulbus showed progression, treated by chemotherapy. In two patients, a combined supra-orbital mini-craniotomy plus orbital frame osteotomy was used for intraorbital tumor resection + intradural pre-chiasmatic dissection. In these two patients, remnants of the optic nerve within the optic canal remained stable. No patient had a chiasmatic functional affection nor permanent oculomotor deficits. In selected patients, a surgical resection from bulb to chiasm ± removal of optic canal tumor was safe without long-term sequela and with an excellent cosmetic result. Surgery normalizes exophthalmos and provides an effective tumor control.

Association between modified frailty index and surgical outcomes in intradural skull base surgery

The objective of this study is to evaluate the impact of preoperative frailty on short-term outcomes following intradural resection of skull base lesions. The 2005–2017 ACS-NSQIP database was queried for 30-day post-operative outcomes of patients undergoing intradural resection of the skull base, extracted by CPT codes 61601, 61606, 61608, and 61616. Five-item modified frailty index (mFI) was calculated based on the history of diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure, chronic hypertension, and functional status. A total of 701 patients (58.8% female, 72.0% white) were included with a mean age of 51.8 ± 14.7 years. Compared to patients with mFI = 0 (n = 403), patients with mFI ≥ 1 (n = 298) were more likely to have higher rates of reoperation (13.4% vs. 8.7%, p = 0.045), medical complications (20.5% vs. 9.2%, p < 0.001), surgical complications (13.8% vs. 8.4%, p = 0.024), discharge to non-home facility (DNHF) (24.8% vs. 13.3%, p < 0.001), and prolonged length of hospitalization (7.3 ± 6.8 days vs. 5.6 ± 5.0, p = 0.003). Moreover, mFI = 1–3 was also associated with higher BMI, non-white race, high ASA, and older age (all p < 0.05). Upon adjusting for age, BMI, race, ASA score, and surgical site, multivariate regression analysis demonstrated that higher mFI (treated as a continuous variable) was associated with higher odds of medical complications (OR = 1.630, CI = 1.153–2.308, p = 0.006), surgical complications (OR = 1.594, CI = 1.042–2.438, p < 0.031), and LOS ≥ 10 days (OR = 1.609, CI = 1.176–2.208, p = 0.003). In conclusion, the 5-item mFI can be an independent predictor of several important short-term surgical outcomes following intradural resection of skull base lesions, warranting further investigations into its clinical utility.

Use of Saito technique to resect an anterior lumbar spine meningioma: Technical note.

Background: Complete (Simpson Grade I: total removal) resections for anterior spinal meningiomas are especially challenging. This is largely attributed to difficulty obtaining a water-tight dural repair where the tumor has infiltrated the dura requiring duroplasty, thus often resulting in just a Simpson Grade II resection (i.e. coagulation of the dural implantation site). Here, we present a 56-year-old female who underwent resection of a ventral lumbar meningioma utilizing the Saito technique, that effectively separated the dura into two layers, removing just the inner layer but leaving the outer layer intact for direct dural repair.Methods: A 56-year-old female underwent a L1–L2 laminectomy. The anterior intradural resection of tumor was achieved with the Saito technique; this required cutting circumferentially around the tumor insertion site, and removing only the inner layer.Results: Postoperatively, the patient did well without tumor recurrence over 8 years. The postoperative biopsy confirmed a World Health Organization Grade I meningothelial meningioma.Conclusion: Saito’s technique proved to be a safe and effective method for achieving gross total resection of an anterior lumbar meningioma.

Dermoid cyst of the lateral wall of the cavernous sinus presenting with isolated abducens nerve palsy

Dear Editor,Dermoid cysts are rare congenital slow growing neoplasmsaccounting for less than 1 % of intracranial tumors [2].Dermoid cysts confined to the lateral wall of the cavernoussinus are extremely unusual and clinical symptoms general-ly occur late in the course of tumor growth, due to localirritative effects of the space-occupying lesion. The mostcommon clinical presentation results from involvement ofthe cranial nerves contained in the lateral wall of the cav-ernous sinus. Accordingly, while trigeminal nerve dysfunc-tion, oculomotor and trochlear nerve palsies with dermoidorigin have been widely described [1, 5], isolated abducensnerve deficit, to the best of our knowledge, has not beenpreviously reported.A 37-year-old man presented with a 1-week history ofprogressive diplopia. On the first examination, a remarkablelimitation in abduction in his right eye was observed (Fig. 1).Magneticresonanceimaging(MR)demonstratedacysticovalshaped lesion in the right parasellar space hypointense tohyperintense on T1- and T2-weighted images, whichpresented a slight rim of enhancement after contrast injection(Fig. 1). The posterior vertical segment and the posteriorbend of the intracavernous carotid artery were displacedantero-medially (Fig 1). Analysis of MR images suggestedthat the tumor was an interdural dermoid cyst of the lateralwall of the cavernous sinus.The patient underwent a right fronto-temporal cranioto-my for intradural resection of the tumor, which was ob-served bulging into and deforming the lateral wall of thecavernous sinus. The outer (or meningeal) layer of thelateral wall was incised over the most prominent part ofthe tumor, and its greasy content associated with hair tuftswas progressively removed. The capsule adherent to theinner (or membranous) layer of the lateral wall of the cav-ernous sinus was dissected and removed in a piecemealfashion.Histopatological examination confirmed that the tumorwas a dermoid cyst.The patient’s postoperative recovery was uneventful. Atthe 1-month follow-up examination, diplopia had resolvedand MR images obtained at this time revealed total tumorresection (Fig. 1).Interdural dermoid cysts of the lateral wall of the cavern-ous sinus have been rarely reported in the literature [1, 5].The lateral dural wall of the cavernous sinus is composed oftwo layers, the outer layer (meningeal layer or dura propria)and the inner membranous layer (or endosteal layer), whichis formed by the dural sleeves of CN III, IVand V1 [3, 7].According to this meningeal architecture, interduraldermoid cysts generally induce symptoms due to involve-ment of the ophthalmic division of the trigeminal nerve,oculomotor nerve and trochlear nerve [1, 5]. In the present

前床突起切除（anterior clinoidectomy）を施行した内頚動脈―後交通動脈分岐部動脈瘤（IC-PC AN）の検討

Most IC-PC ANs could be safely clipped via the pterional approach. However, if ANs are larger or the anterior clinoid process (ACP) can hide the anatomy at the proximal neck, clinoidectomy is sometimes necessary for complete exposure and safe clipping. We examined 57 cases of IC-PC ANs treated with clipping. The ACP was resected in 11 of the 57 cases, which included different techniques for extradural resection for seven cases and intradural resection for four cases, respectively. We recommend extradural clinoidectomy for all ANs close to 1 cm. However, if an AN is less than 1 cm, and satisfactory proximal carotid control or visualization of the neck is obscured by the ACP, then intradural partial clinoidectomy is an effective alternative method.

Extramedullary Ependymoma Near the Conus Medullaris With Lumbar Nerve Root Attachment: Case Report

Ependymomas are the most common primary spinal cord tumor, most frequently located near the cauda equina and conus medullaris. We believe that this is the first reported case of a low-grade, nonmyxopapillary (World Health Organization grade 2), intradural, extramedullary ependymoma involving a spinal nerve root. An 87-year-old woman presented with a chief complaint of acute onset of severe right hip and lateral thigh pain without midline back pain. She had baseline chronic bladder dysfunction, which remained unchanged. Her physical examination was significant for 4/5 strength in her right hip flexion (possibly related to pain), and 5 beats of clonus bilaterally. She had no point tenderness at the level of her compression fracture. Computed tomography of the patient's lumbar spine revealed a well-corticated, chronic compression fracture of the L3 vertebral body. Magnetic resonance images demonstrated an ovoid-shaped, 1.5×1-cm, well-circumscribed, intradural, extramedullary lesion at the conus medullaris. The patient underwent an L1-3 laminectomy with intradural resection of the mass, which was found to be intricately involved with a single nerve root. The nerve root was coagulated and sectioned, and a gross total resection of the tumor was achieved. The patient tolerated the procedure well, with no complications or any postoperative neurological deficit. Her right-sided pain immediately resolved after surgery. Her strength and ambulation were normal after surgery. No adjuvant radiotherapy was offered to the patient. This case illustrates a unique tumor presentation and the successful surgical treatment of the condition.

Surgical Tips for Medial Sphenoid Wing Meningioma

Medial sphenoid wing meningiomas are more problematic than those meningiomas originating at the pterion. Major arteries and perforators are often involved. An essential principle of surgery is given in this paper. In order to do an operation safely, it is important to define at an early stage of surgery whether the arachnoid membrane separates an artery and a tumor. If one cannot find the separating arachnoid, one should decide to leave the part of tumor attached to the artery. I like to use an intradural resection of the anterior clinoid process after removal of the main tumor mass when the tumor is small. In cases of extensive tumors, extradural bone removal is preferred at the initial stage, so that less brain retraction is needed and the feeding artery is managed. Intradurally, one should detach the tumor initially and then debulk it. Tumor can be separated from the brain surface using the arachnoid plane. One must try to preserve large vessels and perforating branches buried in the tumor to avoid major complications. I recommend dividing the tumor into compartments along a blood vessel, so that one can dissect the vessel from the tumor. Simpson 2 removal is usually tried but I do not hesitate to leave part where no arachnoid membrane is separating major vessels or perforators from the tumor. The video shows where to stop removal. In addition, tumor invading into the cavernous sinus is not removed as long as it does not cause ocular motility disorder.

Surgery of Jugular Foramen Tumors

We retrospectively reviewed 129 patients between 1980 and 2004 with tumors centered at the jugular foramen (JF). Our series includes 53 neurinomas, 24 meningiomas, 30 glomus jugulare tumors, and 22 other tumors. Based upon the tumors' location and extension, we classified JF tumors into 3 types, as follows: Type A tumors were primarily intracranial with minimal extension into JF; Type B tumors were dumbbell-shaped with both intra- and extracranial components; and Type C tumors were Type B with high cervical extension. Type A tumors were usually operated through the extreme lateral infrajugular transcondylar (ELITE) approach. The key element of surgical exposure was the extradural resection of the occipital condyle and jugular tubercle. In most of the type A cases, the tumor could be removed by an intradural resection. Type B tumors were usually operated via trans-sigmoid transjugular and ELITE approaches. The key elements of the surgical exposure were infralabyrinthine mastoidectomy, jugular bulb skeletonization, and transcondylar exposure. This type of tumor could be totally resected through a combined intradural and transjugular approach. Type C tumors required a combined trans-sigmoid transjugular and high cervical approach. Most of the extensive glomus tumors and meningiomas required a combined transmastoid transjugular and high cervical approach for radical resection. The facial nerve could be transposed anteriorly exposing the carotid artery. Advances in precise microsurgical techniques and refined instrumentation and skull base approaches have contributed to successful radical resection of JF tumors with decreased morbidity. We will present our classification of JF tumors as Types A, B, and C and describe one-stage operative approaches for each of the three types.

Surgery of Jugular Foramen Tumors

We retrospectively reviewed 129 patients between 1980 and 2004 with tumors centered at the jugular foramen (JF). Our series includes 53 neurinomas, 24 meningiomas, 30 glomus jugulare tumors, and 22 other tumors. Based upon the tumors' location and extension, we classified JF tumors into 3 types, as follows: Type A tumors were primarily intracranial with minimal extension into JF; Type B tumors were dumbbell-shaped with both intra- and extracranial components; and Type C tumors were Type B with high cervical extension. Type A tumors were usually operated through the extreme lateral infrajugular transcondylar (ELITE) approach. The key element of surgical exposure was the extradural resection of the occipital condyle and jugular tubercle. In most of the type A cases, the tumor could be removed by an intradural resection. Type B tumors were usually operated via trans-sigmoid transjugular and ELITE approaches. The key elements of the surgical exposure were infralabyrinthine mastoidectomy, jugular bulb skeletonization, and transcondylar exposure. This type of tumor could be totally resected through a combined intradural and transjugular approach. Type C tumors required a combined trans-sigmoid transjugular and high cervical approach. Most of the extensive glomus tumors and meningiomas required a combined transmastoid transjugular and high cervical approach for radical resection. The facial nerve could be transposed anteriorly exposing the carotid artery. Advances in precise microsurgical techniques and refined instrumentation and skull base approaches have contributed to successful radical resection of JF tumors with decreased morbidity. We will present our classification of JF tumors as Types A, B, and C and describe one-stage operative approaches for each of the three types.

Minimally Invasive Resection of Intradural-Extramedullary Spinal Neoplasms

Spinal intradural-extramedullary neoplasms are uncommon lesions that usually cause pain or neurological deficit secondary to neural compression. Traditional treatment of these tumors includes open laminectomy with intradural resection. We describe an alternative minimally invasive surgical technique in a consecutive series of patients undergoing treatment for symptomatic lesions. Six patients (four men, two women) presented with symptoms including pain (five out of six) and/or neurological deficit (two out of six) with radiographic evidence of intradural pathology. All patients underwent surgical resection using a minimally invasive, unilateral approach. Pain relief was analyzed using the visual analog scale and magnetic resonance imaging to evaluate the extent of resection. Traditional laminectomy for tumor resection disrupts the muscular, ligamentous, and bony structures of the spine, which may contribute to pain and instability. Minimally invasive resection of intradural tumors offers the option of reducing approach morbidity when resecting these lesions. Using a tubular retractor system (X-Tube, Medtronic Sofamor-Danek, Memphis, TN) and microscopic surgical techniques, we were able to resect different intradural lesions successfully. All patients underwent successful, complete resection of their intradural-extramedullary tumors. The average patient age was 47 years (range, 41-60 yr) with one cervical, one thoracic, and four lumbar lesions. The mean operative time was 247 minutes (range, 180-320 min), the estimated blood loss was 56 mLs (range, 40-75 mLs), and the hospital stay was 57 hours (range, 48-80 h). Histologically, five tumors were determined to be schwannomas and one was identified as a myxopapillary ependymoma. There were no complications associated with this surgical technique. Postoperative magnetic resonance imaging demonstrated complete resection in all cases. Intradural-extramedullary neoplasms can be safely and effectively treated with minimally invasive techniques. Potential reduction in blood loss, hospitalization and disruption to local tissues suggest that, in the hands of an experienced surgeon, this technique may present an alternative to traditional open tumor resection.

Transpalatopharyngeal approach to clivus-craniocervical chordomas

The transoral-transpalatopharyngeal approach to the ventral clivus and upper cervical spine is now well established. The primary indication for its use in craniocervical chordomas is an extradural mass from the midclivus down to the level of C3 and laterally for 2 cm to either side of the midline. The procedure may be combined with a lateral rhinotomy, maxillary dropdown procedure, mandibular split with midline glossotomy, and transphenoidal approach. In my experience with 48 patients with craniocervical chordomas (1985 through 2001), this approach was used in 18 patients. It may be used as a primary procedure or as a staged second procedure for radical resection of the lesion. Reconstruction of the intradural resection of tumor is made with a dural closure that is reinforced with fascia, fat, and tissue glue. The integrity is maintained with lumbar subarachnoid drainage.