Chandranath Sen

The Transoral Approach for the Management of Intradural Lesions at the Craniovertebral Junction: Review of 7 Cases

The main difficulty in dealing with intradural lesions located ventrally in the region of the craniovertebral junction (CVJ) is related to their relative inaccessibility. Posterolateral approaches involve some manipulation of the brain stem and provide limited access because of the necessity of working between the cranial nerves. Even then, the view of the ventral midline and across is limited. The transoral approach, which has been widely used for the management of extradural lesions in this area, is also useful for the treatment of intradural lesions. It provides an unimpeded although somewhat restricted, view of the ventral aspect of the CVJ without the need for brain retraction. The cranial nerves and vertebral arteries are not interposed between the surgeon and the lesion. The risks of cerebrospinal fluid leakage and infection are greatly diminished by the use of fibrin adhesive and prolonged diversion of the cerebrospinal fluid. The use of this approach, together with its technical difficulties and results, in the management of seven purely intradural lesions located ventrally at the CVJ, is discussed.

Direct vein graft reconstruction of the cavernous, petrous, and upper cervical internal carotid artery : lessons learned from 30 cases

The authors report a series of 30 patients who underwent reconstruction of the internal carotid artery (ICA) at the skull base with the saphenous vein during the surgical management of lesions at the cranial base. This group represents about 9% of the total patients in whom the ICA in the cavernous or petrous segment was manipulated either during the surgical approach or dissection from the tumor. Two of these patients failed a clinical balloon test occlusion of the ICA, and, in 9 patients, cerebral blood flow during balloon test occlusion dropped to between 15 to 30 ml/100g/min. The patency rate is 86% over a mean follow-up time of 18 months. Of the 4 patients with graft occlusion, 3 were asymptomatic. The fourth patient who suffered ICA dissection with graft occlusion subsequently died from a massive cerebral infarction. Three patients with inadequate collateral circulation sustained minor strokes as the result of the temporary ICA occlusion during the grafting, but all are capable of leading independent lives. Two patients suffered acute graft occlusion within 12 hours of the surgery and underwent successful revision of the graft. None of the grafted patients suffered delayed occlusion or ischemic or embolic problems. The patients with malignant tumors died within 2 years of the operation from the original disease; total tumor removal was accomplished in 14 of the 19 patients with benign tumors. The aneurysms were successfully eliminated in all 5 patients. The lessons learned from this experience are discussed.

Clival chordomas: clinical management, results, and complications in 71 patients

OBJECT Chordomas are rare malignant neoplasms arising predominantly at the sacrum and skull base. They are uniformly lethal unless treated with aggressive resection and proton beam irradiation. The authors present results of the surgical management of a large number of patients with clivus chordomas. Factors that influence the surgeons ability to achieve radical tumor resection are also evaluated. METHODS Between 1991 and 2005, 71 patients with clivus chordomas underwent surgery. The average follow-up was 66 months (median 60 months, range 3-189 months). Sixty-five patients had complete records that were analyzed in the present report. Thirty-five percent of them had undergone surgery before being treated by the authors. They were evaluated with MR imaging and CT scanning and underwent surgery utilizing a variety of skull base techniques aimed at achieving radical excision. Many also underwent postoperative radiation, usually in the form of proton beam therapy. The patients were followed up with serial imaging at regular intervals as well as with neurological evaluation. RESULTS Radical tumor resection was achieved in 58% of the group. The overall 5-year survival rate was 75%. Radical resection had a positive impact on survival. The ability to achieve radical resection was dependent on the preoperative tumor volume and the number of anatomical areas involved by the tumor. Cranial nerve impairment and CSF leakage were the most frequent postoperative complications. CONCLUSIONS Radical excision is the ideal surgical goal in the treatment of clival chordomas and can be achieved with reasonable risks. Several different surgical approaches may be necessary to accomplish this.

Applications of Fast-Setting Hydroxyapatite Cement: Cranioplasty

A variety of autogenous and synthetic materials have been used to repair cranial defects resulting from traumatic and iatrogenic causes. In theory, the ideal material should be readily available and safe. It should adequately protect the underlying central nervous system, resist cerebrospinal fluid fistula formation, and be easily contoured. One promising synthetic biomaterial that has been used for cranioplasty is hydroxyapatite cement. This biomaterial has successfully restored cranial contour in most patients in whom it has been used; however, difficulties have arisen because of the materials prolonged water solubility. When exposed to cerebrospinal fluid or blood, inadequate setting of the cement occurs, resulting in loss of its structural integrity. This problem can be alleviated with the use of fast-setting hydroxyapatite cement, which hardens 6 to 12 times faster than the traditional cement. We present, to the best of our knowledge, the first series of the use of this material in 21 patients requiring cranioplasty. The advantages and limitations of fast-setting hydroxyapatite cement will be discussed. (Otolaryngol Head Neck Surg 2000; 123:409-12.)

Jugular foramen: microscopic anatomic features and implications for neural preservation with reference to glomus tumors involving the temporal bone.

OBJECTIVEOur goals were to study the normal histological features of the jugular foramen, compare them with the histopathological features of glomus tumors involving the temporal bone, and thus provide insight into the surgical management of these tumors with respect to cranial nerve function. METHODSTen jugular foramen blocks were obtained from five human cadavers after removal of the brain. Microscopic studies of these blocks were performed, with particular attention to fibrous or bony compartmentalization of the jugular foramen, the relationships of the caudal cranial nerves to the jugular bulb/jugular vein and internal carotid artery, and the fascicular structures of the nerves. In addition, we studied the histopathological features of 11 glomus tumors involving the temporal bone (10 patients), with respect to nerve invasion, associated fibrosis, and carotid artery adventitial invasion. RESULTSA dural septum separating the IXth cranial nerve from the fascicles of Cranial Nerves X and XI, at the intracranial opening, was noted. Only two specimens, however, had a septum (one bony and one fibrous) producing internal compartmentalization of the jugular foramen. The cranial nerves remained fasciculated within the foramen, with the vagus nerve containing multiple fascicles and the glossopharyngeal and accessory nerves containing one and two fascicles, respectively. All of these nerve fascicles lay medial to the superior jugular bulb, with the IXth cranial nerve located anteriorly and the XIth cranial nerve posteriorly. All nerve fascicles had separate connective tissue sheaths. A dense connective tissue sheath was always present between the IXth cranial nerve and the internal carotid artery, at the level of the carotid canal. The inferior petrosal sinus was present between the IXth and Xth cranial nerves, as single or multiple venous channels. The glomus tumors infiltrated between the cranial nerve fascicles and inside the perineurium. They also produced reactive fibrosis. In one patient, in whom the internal carotid artery was also excised, the tumor invaded the adventitia. CONCLUSIONWithin the jugular foramen, the cranial nerves lie anteromedial to the jugular bulb and maintain a multifascicular histoarchitecture (particularly the Xth cranial nerve). Glomus tumors of the temporal bone can invade the cranial nerve fascicles, and infiltration of these nerves can occur despite normal function. In these situations, total resection may not be possible without sacrifice of these nerves.

Cranial base surgery. Results in 183 patients

ObjectiveTo learn about the effects of cranial base surgery.DesignCohort study with a mean follow-up of 30 months.SettingPopulation-based.PatientsA consecutive sample of 183 patients who underwent cranial base surgery; 118 patients had malignant skull base tumors, majority were previously treated; 50 had benign tumors, 9 patients had congenital malformations of the skull base; 3 patients had inflammatory lesions, and 3 had traumatic defects of the skull base.Main outcome measuresDisease-free interval and overall survival as well as rate of complications and functional statusInterventionCranial base surgery was followed by radiotherapy (in previously untreated patients).ResultsAfter completion of follow-up (30 months, mean), 30 (25.4%) patients had died of their malignant tumors and 8 (6.8%) had died of other causes. One patient (0.84%) was lost to follow-up. The overall cancer survival without regard to histologic type was 67% (63% with no evidence of disease). Among the patients who were treated for benign neoplasm 72% were NED at a mean 39 months of follow-up. The group of patients with congenital malformations, inflammatory, and traumatic lesions demonstrated successful correction of their pre-surgical problem with skull base surgery. One patient (invasive aspergillosis) died of disease. The overall surgical/medical mortality was 2%, complication rate was 33% and Karnofsky performance scale was improved or unchanged postoperatively in 83% of patients. The average duration of surgery, number of blood transfusions used and the length of the hospital stay was 10 hours, 3 units, and 15 days respectively.ConclusionsCranial base surgery is a valid surgical technique for cranial base afflictions. In this study it was found to be beneficial in controlling benign as well as malignant disease and be the treatment of choice in selected congenital malformations, trauma, and inflammatory lesions.

Cervical Transdural Intramedullary Migration of a Sublaminar Wire| A Complication of Cervical Fixation

Wire breakage after a cervical occiput to C2 wire fixation and fusion resulted in the transdural and intramedullary migration of a wire fragment in a patient who remained neurologically intact. The risks of sublaminar wiring fixation are discussed, along with newer techniques for posterior cervical stabilization.

Management of the Vertebral Artery in Excision of Extradural Tumors of the Cervical Spine Technique and Application: 106

ABSTRACT: EXTRADURAL TUMORS OF the cervical spine may involve the vertebral artery on one or both sides, posing one of the limiting factors toward the radical resection of such neoplasms. A standard anterior approach may be inadequate for the management of such tumors. An anterolateral approach allows the dissection and mobilization of the vessel, which can then be preserved, resected, or reconstructed with a vein graft. An anterior approach can be supplemented with this for tumor resection and stabilization. This management strategy is described in 10 patients with a variety of tumors.

Globe Sparing Orbital Exenteration

OBJECTIVE: Orbital exenteration has long been the oncologic standard for malignant craniofacial lesions that invade the periorbita/orbit from adjacent locations. Although oncologically sound, this radical surgical procedure is cosmetically disfiguring for all patients. Most of the reconstructive options available are complex, requiring further surgery and/or expense. We herein introduce an alternative surgical technique for radical orbital surgery that spares the globe, thereby allowing an early, aesthetic appearance at a nominal cost. STUDY DESIGN AND SETTING: Twenty consecutive patients requiring an oncologic orbital exenteration and meeting the indications for the new procedure underwent surgery at a tertiary care medical center. Follow-up ranged from 1 to 6 years. RESULTS: Only 1 patient recurred in the orbit due to an error in patient selection. There was no surgical morbidity resulting from the globe-sparing technique itself. CONCLUSION: Globe-sparing orbital exenteration is a one-step, oncologically sound, aesthetically superior, low-cost alternative for those patients requiring radical orbital surgery and reconstruction.

Treatment of a complex posterior fossa aneurysm in a child using side-to-side posterior inferior cerebellar artery–posterior inferior cerebellar artery bypass

Endovascular and cerebral bypass therapies are rarely used in children. The authors describe the treatment of a partially coiled giant distal vertebral artery (VA)-posterior inferior cerebellar artery (PICA) aneurysm in a child. They performed a side-to-side PICA-PICA anastomosis followed by endovascular VA aneurysm deconstruction with PICA preservation. A healthy 11-year-old boy developed progressive holocephalic headaches over the course of 2 months. Magnetic resonance imaging and magnetic resonance angiography revealed a large right PICA aneurysm causing brainstem compression. In November 2005, 2 Neuroform stents and Guglielmi detachable coils and Matrix were placed in the aneurysm at an outside institution. In 2006, angiography demonstrated aneurysm enlargement from which the PICA originated, coil compaction, and increased mass effect. The patient underwent a PICA-PICA bypass with intraoperative flow measurements followed by endovascular embolization of the aneurysm and parent VA. An angiogram obtained after the procedure demonstrated filling of the right PICA medullary branch through the bypass and obliteration of the aneurysm. The patient remained neurologically intact. Giant aneurysms of the posterior circulation are rare but do occur in children. With the aid of combined surgical and endovascular strategies the authors were able to safely eliminate the aneurysm from circulation with good outcome. Cerebral bypass and endovascular deconstructive therapies can be used safely in children but should be reserved for cases in which direct treatment carries significant risk. Careful surgical and endovascular planning with intraoperative flow assessment is essential for good outcome.