Jeffrey D. Klopfenstein

Intraoperative Iso-C C-Arm Navigation in Craniospinal Surgery: The First 60 Cases

OBJECTIVE:The intraoperative Iso-C C-arm (Siremobil Iso-C 3D; Siemens Medical Solutions, Erlangen, Germany) provides a unique ability to acquire and view multi-planar three-dimensional images of intraoperative anatomy. Registration for intraoperative surgical navigation may be automated, thus simplifying the operative workflow. METHODS:Iso-C C-arm intraoperative fluoroscopy acquires 100 images, each of which must be 1.8 degrees in a circumferential fashion about an “isocentric” point in space. The system generates a high-resolution isotropic three-dimensional data set that is available immediately after the 90-second C-arm rotation. The data set is ported to the image-guided workstation, registration is immediate and automated, and the surgeon can navigate with millimetric accuracy. The authors prospectively examined data from the initial 60 patients examined with the Iso-C, among whom were cases of anterior and posterior spinal instrumentation from the occiput to the sacrum. Percutaneous and minimally invasive spinal and cranial procedures were also included. RESULTS:Automated registration for image-guided navigation was attainable for anterior and posterior cases from the cranial base and entire spine. In most cases, intraoperative postprocedural imaging with the Iso-C mitigated the need for postoperative imaging. CONCLUSION:Intraoperative Iso-C three-dimensional scanning allows real-time feedback during cranial base and spinal surgery and during procedures involving instrumentation. In most cases, it obviates the need for postoperative computed tomography. Its usefulness is in its simplicity, and it can be easily adapted to the operating room workflow. When coupled with intraoperative navigation, this new technology facilitates complex neurosurgical procedures by improving the accuracy, safety, and time of surgery.

Transcranial Motor Evoked Potentials during Basilar Artery Aneurysm Surgery: Technique Application for 30 Consecutive Patients

OBJECTIVEMicrosurgical clipping of basilar artery aneurysms carries a risk of neurological compromise resulting from midbrain or thalamic ischemia. Somatosensory evoked potential (SSEP) monitoring and electroencephalography are the standard techniques for assessing the level of cerebroprotective anesthesia and monitoring ischemia during temporary occlusion or after permanent clipping. Transcranial motor evoked potential (TcMEP) monitoring was added to determine whether this modality improved intraoperative monitoring. METHODSCombined SSEP/electroencephalographic/TcMEP monitoring was used for 30 consecutive patients with basilar artery apex aneurysms in the past 1.5 years. Voltage thresholds were recorded before, during, and after aneurysm treatment for the last 10 patients. RESULTSAll 30 patients underwent an orbitozygomatic craniotomy for clipping (28 patients), wrapping (1 patient), or superficial temporal artery-superior cerebellar artery bypass (1 patient). Electrophysiological changes occurred for 10 patients (33%), elicited by temporary clipping (6 patients), permanent clipping (3 patients), or retraction (1 patient). Isolated SSEP changes were observed for one patient, isolated TcMEP changes for five patients, and changes in both TcMEPs and SSEPs for four patients. Among patients with simultaneous changes, TcMEP abnormalities were more robust and occurred earlier than SSEP abnormalities. Impaired motor conduction was detected first with an increase in the voltage threshold (from 206 ± 22 to 410 ± 49 V, P < 0.05, n = 3) and then with loss of TcMEP responses. SSEP and TcMEP signals returned to baseline values for all patients after corrective measures were taken. CONCLUSIONTcMEP monitoring can be safely and easily added to traditional neurophysiological monitoring during basilar artery aneurysm surgery. These results suggest that TcMEPs may be more sensitive than SSEPs to basilar artery and perforating artery ischemia. This additional intraoperative information might minimize the incidence of ischemic complications attributable to prolonged temporary occlusion or inadvertent perforator occlusion.

Incidence and pattern of direct blunt neurovascular injury associated with trauma to the skull base.

OBJECT Skull base fractures are often associated with potentially devastating injuries to major neural arteries in the head and neck, but the incidence and pattern of this association are unknown. METHODS Between April and September 2002, 1738 Level 1 trauma patients were admitted to St. Josephs Hospital and Medical Center in Phoenix, Arizona. Among them, a skull base fracture was diagnosed in 78 patients following computed tomography (CT) scans. Seven patients had no neurovascular imaging performed and were excluded. Altogether, 71 patients who received a diagnosis of skull base fractures after CT and who also underwent a neurovascular imaging study were included (54 men and 17 women, mean age 29 years, range 1-83 years). Patients underwent CT angiography, magnetic resonance angiography, or digital subtraction angiography of the head and craniovertebral junction, or combinations thereof. RESULTS Nine neurovascular injuries were identified in six (8.5%) of the 71 patients. Fractures of the clivus were very likely to be associated with neurovascular injury (p < 0.001). A high risk of neurovascular injury showed a strong tendency to be associated with fractures of the sella turcica-sphenoid sinus complex (p = 0.07). CONCLUSIONS The risk of associated blunt neurovascular injury appears to be significant in Level 1 trauma patients in whom a diagnosis of skull base fracture has been made using CT. The incidence of neurovascular trauma is particularly high in patients with clival fractures. The authors recommend neurovascular imaging for Level 1 trauma patients with a high-risk fracture pattern of the central skull base to rule out cerebrovascular injuries.

Indications for surgical fusion of the cervical and lumbar motion segment.

Study Design. A literature review and the authors’ clinical experience for the indication of fusion in the degenerative lumbar and cervical spine is provided. Objective. To establish absolute and relative criteria for the indication for fusion in the degenerative cervical and lumbar spine. Summary of Background Data. Fusion in the cervical and lumbar degenerative spine is indicated under certain strict criteria. However, fusion in circumstances not meeting these criteria is controversial. Method. A review of the literature and the authors’ experience concerning indication and criteria of fusion in degenerative, lumbar, and cervical spine is provided. Results. Fusion for the unstable spine related to trauma, infection, and tumors is relatively accepted. However, indications for fusion for degenerative, cervical, and lumbar spine are more controversial. Conclusion. Lumbar and cervical fusion in the degenerative spine is frequently performed. Certain criteria have been established when a fusion should be considered. However, even these are not universally accepted. Strict prospective studies are needed to determine when a fusion of the degenerative, cervical, and lumbar spine is indicated. Patients with severe radicular pain may be considered for surgery after a comprehensive trial of conservative management. Fusion is usually necessary after a cervical discectomy, especially when spondylosis or osteophytic compression is present. Lumbar fusion is rarely indicated for routine discectomy. In patients with mechanical back or neck pain, surgery should only be considered after conservative measures have been exhausted and a radiographic abnormality is present at the symptomatic level, perhaps with pain concordant with discographic findings. Careful patient selection is the key to obtaining favorable surgical outcomes. In many cases, the goal may be a return to functionality rather than achieving a completely asymptomatic state.

Postoperative Acute Sialadenitis after Skull Base Surgery

During retrosigmoid and far-lateral skull base surgical approaches, the head may be positioned at the extreme limits of rotation and flexion. In rare instances, patients may develop acute sialadenitis after surgery as a result of this positioning technique. Over a 4-year period, five patients developed postoperative sialadenitis after undergoing either a retrosigmoid craniotomy in the supine position (n = 4) or a far-lateral craniotomy in the park-bench position. Based on all the retrosigmoid and far-lateral approaches performed by the senior author (RFS), the incidence of sialadenitis was 0.84%. In all five patients, the acute sialadenitis was not clinically apparent at the conclusion of the operation. However, the diagnosis was evident within 4 hours of surgery. In each case, the neck swelling in the vicinity of the submandibular gland was contralateral to the craniotomy site. All patients were treated with intravenous hydration and antibiotic therapy. One patient was extubated immediately after surgery with no obvious evidence of sialadenitis. However, she required emergent reintubation due to airway compromise. The mechanism of acute sialadenitis in these patients was obstruction of the salivary duct caused by surgical positioning. This previously unreported observation in patients undergoing skull base surgery deserves consideration during perioperative and postoperative management.

Preserving Olfactory Function in Anterior Craniofacial Surgery through Cribriform Plate Osteotomy Applied in Selected Patients

OBJECTIVE: Olfaction is often sacrificed to gain access to the cranial base in anterior craniofacial surgery. We describe the long-term results of olfactory function in patients who underwent anterior craniofacial surgery and a cribriform plate osteotomy to preserve olfaction. METHODS: Between 1992 and 2004, 28 patients underwent 29 cribriform plate osteotomies in an attempt to preserve olfaction during anterior craniofacial surgery performed through modified extended transbasal approaches. Patients’ charts and office notes were reviewed retrospectively. Formal olfactory testing was available in 5 patients, but most data were based on patients’ subjective reports of olfaction. Olfactory preservation was defined by the subjective ability to detect fumes such as coffee, chocolate, roses, and orange juice regardless of the intensity of the sensation. Follow-up was based on phone calls to patients. RESULTS: Four patients were lost to follow-up and excluded. Therefore, follow-up was available in 24 patients after 25 procedures. On the basis of patients’ subjective reports, olfaction was spared in 22 patients after 23 procedures (92%) and was confirmed objectively in the five patients formally tested. After surgery, only two patients were anosmic. CONCLUSION: Olfaction can be preserved in selected patients undergoing anterior craniofacial surgery. At least 1 cm of nasal mucosa should remain attached to the cribriform plate, which can be achieved by including the nasal bone in the osteotomy of the orbital bar. A medial orbital canthopexy is therefore necessary after these procedures.

Exposure of midline cranial base without a facial incision through a combined craniofacial-transfacial procedure

OBJECTIVE: A single-stage combined craniofacial-transfacial approach that exposes the midline cranial base without visible facial incisions is described. METHODS: Between 1992 and 1998, eight patients underwent surgery for five different anterior cranial base pathological findings: four angiofibromas, one mesenchymal chondrosarcoma, one esthesioneuroblastoma, one odontogenic myxoma, and one encephalocele. In all cases, the surgical exposure consisted of a bicoronal scalp incision with a bifrontal craniotomy and fronto-orbitonasal osteotomy, and then a sublabial incision for transmaxillary exposure. RESULTS: Gross total resection was achieved in five cases. The encephalocele was resected with complete reconstruction of the bony defect. Seven patients developed complications, primarily wound infections, cerebrospinal fluid leaks, and anemia. Postoperative Karnofsky Performance Scale scores ranged between 80 and 100 (mean, 92.5). Long-term follow-up information (mean, 56 mo; median, 59.5 mo; range, 5–108 mo) was available for all patients. CONCLUSION: Large anterior cranial base lesions can be resected and excellent cosmetic outcomes can be achieved with a single-stage combined transfacial-craniofacial approach that exposes the entire midline cranial base and requires no facial incisions.

Clip reconstruction and sling wrapping of a fusiform aneurysm : Technical note

OBJECTIVE To describe an alternative method of clip reconstruction and wrapping of fusiform aneurysms that provides structural support for the reconstructed parent artery or residual aneurysm. CLINICAL PRESENTATION A 57-year-old woman with an unruptured distal middle cerebral artery fusiform aneurysm underwent surgical treatment via a pterional craniotomy. TECHNIQUE A right-angled titanium clip was used to obliterate the aneurysm and to clip reconstruct the parent vessel, which was composed of a single inflow and outflow vessel. After the aneurysm was decompressed with a fine-gauge needle, the remnant/parent artery was wrapped with a thin layer of muslin gauze followed by circumferential application of the Gore-tex (W.L. Gore and Associates, Inc., Flagstaff, AZ) sling. Finally, a second right-angled aneurysm clip was applied to the free ends of the sling immediately adjacent to the parent vessel while the sling was cinched against the parent vessel. This maneuver allowed the Gore-tex material to buttress the reconstructed vessel circumferentially. CONCLUSION Clip reconstruction with a Gore-tex sling preserves the parent vessel and simultaneously buttresses the reconstructed vessel wall with radial forces provided by the Gore-tex material. This method is a novel alternative to conventional methods for the treatment of fusiform aneurysms.

Spinal cord cavernous malformations: management and technical considerations

Abstract Spinal cord cavernous malformations present a unique challenge to neurosurgeons. Neurological deterioration is usually the result of multiple hemorrhages leading to a step-wise decline. On rare occasions, however, acute hemorrhagic events can cause severe, lasting spinal cord injury. Therefore, surgical decision-making can be problematic. This article presents the treatment strategy used at our institution. Essential points of surgical technique and surgical outcomes are also discussed.

Surgical management of distal coil migration and arterial perforation after attempted coil embolization of a ruptured ophthalmic artery aneurysm : Technical case report. Commentary

OBJECTIVE AND IMPORTANCE: Distal coil migration is a rare but hazardous complication of aneurysm coil embolization. Various microsnare devices have been developed to address this problem. We describe the surgical management of a case in which microsnare retrieval failed. CLINICAL PRESENTATION: A 34-year-old woman presented with subarachnoid hemorrhage. Magnetic resonance imaging, computed tomography angiography, and conventional angiography showed an approximately 2.5-mm ophthalmic artery aneurysm. Using balloon remodeling, a 2 x 4-cm coil was deployed into the aneurysm fundus. While the coil pusher was being removed after deployment, the microcatheter advanced abruptly into the aneurysm. The coil mass was dislodged and migrated into the angular branch of the middle cerebral artery. Contrast extravasation was noted during attempted retrieval with a microsnare device. TECHNIQUE: Computed tomographic scans showed a subarachnoid hemorrhage in the territory of the left frontotemporal operculum. A left modified orbitozygomatic approach was performed. The coil mass was removed from the angular artery and a thromboembolectomy was performed. The artery was repaired and the pseudoaneurysm was clip ligated. The ophthalmic artery aneurysm was clip ligated. The patient recovered without deficits. CONCLUSION: Distal coil migration and arterial perforation can be treated surgically with a good clinical outcome.OBJECTIVE AND IMPORTANCE: Distal coil migration is a rare but hazardous complication of aneurysm coil embolization. Various microsnare devices have been developed to address this problem. We describe the surgical management of a case in which microsnare retrieval failed. CLINICAL PRESENTATION: A 34-year-old woman presented with subarachnoid hemorrhage. Magnetic resonance imaging, computed tomography angiography, and conventional angiography showed an approximately 2.5-mm ophthalmic artery aneurysm. Using balloon remodeling, a 2 × 4-cm coil was deployed into the aneurysm fundus. While the coil pusher was being removed after deployment, the microcatheter advanced abruptly into the aneurysm. The coil mass was dislodged and migrated into the angular branch of the middle cerebral artery. Contrast extravasation was noted during attempted retrieval with a microsnare device. TECHNIQUE: Computed tomographic scans showed a subarachnoid hemorrhage in the territory of the left frontotemporal operculum. A left modified orbitozygomatic approach was performed. The coil mass was removed from the angular artery and a thromboembolectomy was performed. The artery was repaired and the pseudoaneurysm was clip ligated. The ophthalmic artery aneurysm was clip ligated. The patient recovered without deficits. CONCLUSION: Distal coil migration and arterial perforation can be treated surgically with a good clinical outcome.