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PubMed2001

Intraoperative wake-up procedure with propofol and laryngeal mask for optimal excision of brain tumour in eloquent areas.

This is the first thesis describing a new technique for awake craniotomy using a laryngeal mask. Awake craniotomy with propofol infusion has become increasingly popular for the optimal excision of brain tumours located in eloquent areas. During awake craniotomy, tracheal intubation is not performed and propofol infusion is limited to within doses which render the patient just sedated. This asleep-awake procedure is occasionally associated with difficulty in controlling brain volume, especially in patients with a significant mass effect of their brain tumours, since sufficient sedation with propofol tends to cause hypercapnea. We report an intraoperative wake-up procedure employing a laryngeal mask, which enables general anaesthesia to be performed at a sufficient dose of propofol and with control of the brain volume under mechanically assisted ventilation. Before the beginning of cortical mapping, propofol infusion is completely terminated, so allowing the patient to wake up within 5-15 min. Following completion of the tumour excision, general anaesthesia is re-induced at a sufficient dose of propofol. The laryngeal mask can be temporarily removed and repositioned with ease, if necessary. In our experience, this technique is applicable for the optimal excision of brain tumours, especially in patients who are very obese or those who have very large lesions.

Anesthetics, Intravenous↗

PubMed2003

Endoscopic-assisted craniofacial resection of esthesioneuroblastoma: minimizing facial incisions--technical note and report of 3 cases.

The surgical management of esthesioneuroblastoma with anterior skull base involvement has traditionally been craniofacial resection, which combines a bifrontal craniotomy with a transfacial approach. The latter usually involves a disfiguring facial incision, mid-facial degloving, lateral rhinotomy, and/or extensive facial osteotomies, which may be cosmetically displeasing to the patient. The advent of angled endoscopes has provided excellent magnification and illumination for surgeons to remove tumors using minimally invasive techniques. The authors describe their experience with three cases of esthesioneuroblastoma, which were surgically removed using a transnasal endoscopic approach, avoiding transfacial incisions. Preoperative radiographs were reviewed and tumors were staged according to the Kadish staging system. One patient had a recurrent esthesioneuroblastoma (Kadish stage B), which was removed entirely through a transnasal endoscopic approach. Two patients had intracranial extension (Kadish stage C), which were resected with a combined approach, endoscopically from below and a bifrontal craniotomy from above, to remove intracranial disease. All patients underwent reconstruction of the anterior skull base. Esthesioneuroblastomas confined to the nasal and paranasal cavities (Kadish stage A and B) were readily accessible through the transnasal endoscopic approach. If there was significant intracranial disease (Kadish stage C), adding a bifrontal craniotomy provided excellent exposure for complete resection of involved tumor. All patients underwent complete tumor resection with negative margins. None developed a cerebrospinal fluid (CSF) leak. The endoscopic-assisted craniofacial approach for the surgical management of esthesioneuroblastomas provides excellent exposure, adequate visualization, and the cosmetic benefit of avoiding an external facial incision.

Adult↗

PubMed2006

Microsurgical excision of the large or giant cerebellopontine angle meningioma.

OBJECTIVE: The object of this study was to analyze the therapeutic effects of microsurgical excision in cases with the large or giant cerebellopontine angle meningioma. METHODS: We retrospectively analyzed the 56 patients who suffered from the large or giant cerebellopontine angle meningioma and underwent the microsurgical therapy, for which the suboccipital-retrosigmoidal approach was adopted in 38 cases, the temporal-occipital craniotomy, presigmoidal approach in 6 cases, the temporal-occipital craniotomy, inferotemporal tentorium cerebelli approach in 8 cases, and the temporal-occipital craniotomy, supratentorial or infratentorial allied approach in 4 cases. RESULTS: The tumors of 44 cases were all resected (Simpson I, II), with a total resection rate of 78.6%, and there was no operative mortality. After surgery, symptoms improved in 40 cases and remained unchanged in 10 cases. Among 54 cases, recrudescence was seen in 2 cases (3.7%) and being able to take care of themselves in 50 cases (92.6%) at 6 months through 6 years follow-up after surgery. CONCLUSION: A rationally selected surgical approach, a microscopic technology applied in the operation to appropriately treat and protect vein, nerve and brain stem, which can ideally excise the tumors, together can increase the survival ability of patients.

Adolescent↗

PubMed2004

Supraorbital keyhole surgery for optic nerve decompression and dura repair.

Supraorbital keyhole surgery is a limited surgical procedure with reduced traumatic manipulation of tissue and entailing little time in the opening and closing of wounds. We utilized the approach to treat head injury patients complicated with optic nerve compression and cerebrospinal fluid leakage (CSF). Eleven cases of basal skull fracture complicated with either optic nerve compression and/or CSF leakage were surgically treated at our department from February 1995 to June 1999. Six cases had primary optic nerve compression, four had CSF leakage and one case involved both injuries. Supraorbital craniotomy was carried out using a keyhole-sized burr hole plus a small craniotomy. The size of craniotomy approximated 2 x 3 cm2. The optic nerve was decompressed via removal of the optic canal roof and anterior clinoid process with high-speed drills. The defect of dura was repaired with two pieces of tensa fascia lata that were attached on both sides of the torn dural defect with tissue glue. Seven cases with optic nerve injury included five cases of total blindness and two cases of light perception before operation. Vision improved in four cases. The CSF leakage was stopped successfully in all four cases without complication. As optic nerve compression and CSF leakage are skull base lesions, the supraorbital keyhole surgery constitutes a suitable approach. The supraorbital keyhole surgery allows for an anterior approach to the skull base. This approach also allows the treatment of both CSF leakage and optic nerve compression. Our results indicate that supraorbital keyhole operation is a safe and effective method for preserving or improving vision and attenuating CSF leakage following injury.

Adolescent↗

PubMed1994

Modification of the cortical impact model to produce axonal injury in the rat cerebral cortex.

Diffuse axonal injury (DAI) is a form of brain injury that is characterized by morphologic changes to axons throughout the brain and brainstem. Previous biomechanical studies have shown that primary axonal dysfunction, ranging from minor electrophysiologic disturbances to immediate axotomy, can be related to the rate and level of axonal deformation. Some existing rodent head injury models display varying degrees of axonal injury in the forebrain and brainstem, but the extent of axonal damage in the forebrain has been limited to the contused hemisphere. This study examined whether opening the dura mater over the contralateral hemisphere could direct mechanical deformation across the sagittal midline and produce levels of strain sufficient to cause a more widespread, bilateral forebrain axonal injury following cortical impact. Intracranial deformation patterns produced by this modified cortical impact technique were examined using surrogate skull-brain models. Modeling results revealed that the presence of a contralateral craniotomy significantly reduced surrogate tissue herniation through the foramen magnum, allowed surrogate tissue movement across the sagittal midline, and resulted in an appreciable increase in the shear strain in the contralateral cortex during the impact. To evaluate the injury pattern produced using this novel technique, rat brains were subjected to rigid indentor impact injury of their left somatosensory motor cortex (1.5 mm indentation, 4.5-4.9 m/sec velocity, and 22 msec dwell time) and examined after a 2-7 day survival period. Neurofilament immunohistochemistry revealed numerous axonal retraction balls in the subcortical white matter and overlying deep cortical layers in the right hemisphere beneath the contralateral craniotomy. Retraction balls were not seen at these positions in normals, sham controls, or animals that received cortical impact without contralateral craniotomy and dural opening. The results from these physical modeling and animal experiments indicate that opening of the contralateral dura mater permits translation of sufficient mechanical deformation across the midline to produce a more widespread pattern of axonal injury in the forebrain, a pattern that is distinct from those produced by existing fluid percussion and cortical impact techniques.

Animals↗

PubMed2001

Hemostatic changes in pediatric neurosurgical patients as evaluated by thrombelastograph.

UNLABELLED: Thromboembolic events are a known complication in neurosurgical patients. There is evidence to suggest that a hypercoagulable state may develop perioperatively. Thrombelastograph (TEG) coagulation analysis is a reliable method of evaluating hypercoagulability. We evaluated coagulation by using TEG data in pediatric neurosurgical patients undergoing craniotomy to determine whether a hypercoagulable state develops intraoperatively or postoperatively. Thirty children undergoing craniotomy for removal of a tumor or seizure focus were studied. Blood was analyzed with TEG) data by using native and celite techniques, at three time points for each patient: preoperatively after induction of anesthesia; intraoperatively during closure of the dura; and on the first postoperative day. Compared with preoperative indices, closing and postoperative celite TEG values were indicative of hypercoagulability with shortened coagulation time values (P < 0.001), prolonged alpha angle divergence values (P < 0.001), and above-normal TEG coagulation indices (P < or = 0.002). Reaction time values were shortened, and maximal amplitude of clot strength values were prolonged but did not reach statistical significance. Hypercoagulation develops early after resection of brain tissue in pediatric neurosurgical patients as assessed by using TEG data. Further studies are needed to determine the clinical significance of this hypercoagulable state. IMPLICATIONS: Hypercoagulability in postoperative neurosurgical patients has been demonstrated in the adult population, but few studies have dealt with the pediatric population. We found that children undergoing craniotomy for focal resection, lobectomy, and hemispherectomy are hypercoagulable as detected by thrombelastograph coagulation analysis. Further studies are needed to determine whether this is clinically significant.

Adolescent↗

PubMed1991

Frontal bone advancement and compensatory craniofacial growth changes in rabbits with experimental coronal suture immobilization.

Recent clinical advances in the surgical correction of coronal suture synostosis involve the overcorrection of a frontal bone segment to allow for unrestricted expansion of the developing neurocapsular matrix. However, the effects of such large-scale calvarial repositioning on subsequent brain mass growth trajectories and compensatory cranio-facial growth changes is unclear. This study was designed to investigate this relationship in an experimental rabbit model of bilateral coronal suture synostosis. Amalgam markers were placed across the frontonasal, coronal, and anterior lambdoid sutures in thirty-one 1.5-week-old rabbits. Twenty-one animals underwent bilateral coronal suture immobilization using methyl-methacrylate. Ten animals were left untreated and served as sham controls. At 6 weeks of age, the coronal suture was released by frontal bone craniotomy or frontal bone craniotomy with a 6-mm frontal bone advancement. Lateral head radiographs were taken at 1.5, 6, 7, 9, 12, and 18 weeks of age. Results revealed that by 6 weeks of age, animals with coronal suture immobilization exhibited growth disturbances across the various sutures resulting in altered craniofacial and cranial vault shape compared to control animals. Following coronal suture release, animals that underwent craniotomy showed rapid restenosis, which resulted in significantly altered cranial vault shape and cranial orthocephalization by 18 weeks of age. Animals that underwent frontal bone advancement exhibited normal overall craniofacial growth by 18 weeks of age compared with control animals but did exhibit regional compensatory growth disturbances at the frontonasal and anterior lambdoid sutures, possibly related to neural tissue distension.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1982

Postcraniotomy diabetes insipidus. Who's at risk?

Diabetes insipidus (DI) is thought to be a relatively common complication after craniotomy procedures. To identify subsets of patients at risk for this problem, the postoperative courses of 135 consecutive patients undergoing craniotomy were scrutinized retrospectively. All patients received similar anesthetic management and all were hospitalized in the ICU postoperatively. DI developed in 9 (5 transient, 4 permanent) of 135 patients (6.7%). All 9 patients developing DI had undergone craniotomy for treatment of a pituitary disorder. It is concluded that postcraniotomy DI is a problem almost exclusively observed in patients with pituitary/hypothalamic disease and that DI rarely occurs in patients with other types of intracranial pathology.

Adult↗

PubMed1992

The clinical utility of computed tomographic scanning and neurologic examination in the management of patients with minor head injuries.

The evaluation and management of patients with minor head injury (MHI: history of loss of consciousness or posttraumatic amnesia and a GCS score greater than 12) remain controversial. Recommendations vary from routine admission without computed tomographic (CT) scanning to mandatory CT scanning and admission to CT scanning without admission for selected patients. Previous reports examining this issue have included patients with associated non-CNS injuries who confound the interpretation of the data and affect outcome. We hypothesized that patients with MHI and no other reason for admission with normal neurologic examinations and normal CT scans would have a negligible risk of neurologic deterioration requiring surgical intervention. To validate this hypothesis we studied 2766 patients with an isolated MHI admitted to seven trauma centers between January 1, 1988, and December 31, 1991. There were 1898 male patients and 868 female patients; injury was blunt in 99%. A neurologic examination and a CT scan were performed on 2166 patients; 933 patients had normal neurologic examinations and normal CT scans and none required craniotomy; 1170 patients had normal CT scans and none required craniotomy; 2112 patients had normal neurologic examinations and 59 required craniotomy. The sensitivity of the CT scan was 100%, with positive predictive value of 10%, negative predictive value of 100%, and specificity of 51%. The use of CT alone as a diagnostic modality would have saved 3924 hospital days, including 814 ICU days, and $1,509,012 in hospital charges. Based on these data, we believe that CT scanning is essential in the management of patients with MHI and that if the neurologic examination is normal and the scan is negative patients can be safely discharged from the emergency room.

Adolescent↗

PubMed1993

Head CT scanning versus urgent exploration in the hypotensive blunt trauma patient.

In hypotensive blunt trauma patients with a diminished level of consciousness, it may be difficult to decide whether to proceed with immediate head CT scanning or urgent laparotomy or thoracotomy. The purpose of this study was to determine the frequency of emergency craniotomy and urgent laparotomy or thoracotomy in a group of 734 blunt trauma patients with initial hypotension (BP < 90 mm Hg systolic) admitted to the eight level I and II trauma centers in North Carolina. The mean initial systolic blood pressure was 64 +/- 26 mm Hg, and the mean Trauma Score was 8 +/- 5.8. Serious head injury (AIS head > or = 3) was present in 40% (293 of 734). Of 734 patients studied, 9.4% (69 of 734) died in the emergency department. Head CT scanning was performed on 47% (344 of 734) and produced positive results for 26% (202 of 734). Emergency craniotomy for intracranial hemorrhage was performed on 2.5% (18 of 734) (ten subdurals, three epidurals, and five other intracranial hemorrhages). Twenty-one percent (154 of 734) underwent urgent laparotomy, thoracotomy, or both. Overall hospital mortality for hypotensive blunt trauma patients was 36% (263 of 734). Although serious head injury occurs commonly (40%) in hypotensive blunt trauma patients, frequency of urgent laparotomy (21%) is 8.5 times greater than emergency craniotomy for intracranial hemorrhage (2.5%). This information may be used by trauma teams in prioritizing care for hypotensive blunt trauma patients.

Abdominal Injuries↗

PubMed1998

Medical treatment of headache after suboccipital acoustic tumor removal.

OBJECTIVES: Suboccipital craniotomy is a frequently used surgical approach for removal of cerebellopontine angle (CPA) tumors. A frequently cited consequence, however, is the high incidence of postoperative headaches. Much has been written regarding prevention of these headaches, but little has been written of their treatment. The authors review their extensive experience in suboccipital tumor removal and the medical management of postoperative headache, highlighting the recent use of a regimen of divalproex sodium and verapamil. STUDY DESIGN: Retrospective chart review. METHODS: The charts of a consecutive series of patients having suboccipital craniotomies for CPA tumors were reviewed. Presence, duration, and severity of headache were noted. Medical treatments and their effectiveness were also noted. RESULTS: Between 1980 and 1997, 228 patients underwent suboccipital craniotomy for removal of CPA tumors. Of these patients, 124 (54.4%) complained of headache. For 62 (27.2%) the headaches persisted for more than a year after surgery. Twenty-nine patients (12.7%) received no relief from any medication. Ten of these patients received a regimen of divalproex sodium and verapamil, with all patients obtaining significant relief. CONCLUSION: Headache is a significant problem with the suboccipital approach for acoustic tumor removal. The majority of patients that complain of headache can be adequately treated with nonsteroidal anti-inflammatory drugs (NSAIDs). If pain is unrelieved by NSAIDs, treatment becomes problematic. The authors' early experience with divalproex sodium/verapamil is encouraging and deserves further investigation as a treatment for these refractory cases.

Adult↗

PubMed2004

The transglabellar subcranial approach for nasal dermoids with intracranial extension.

OBJECTIVES/HYPOTHESIS: Nasal dermoids are the most common congenital midline nasal lesions. When a midline nasal pit or cyst is identified, scans should be obtained to look for an intracranial connection. The intracranial portion of the lesions has traditionally been approached by the performance of a frontal craniotomy. The transglabellar subcranial approach is a useful technique to resect these lesions and offers several advantages over a traditional craniotomy approach. STUDY DESIGN: Retrospective case review. METHODS: Records of two patients who underwent excision of nasal dermoids by way of a subcranial approach were analyzed. RESULTS: Two patients underwent successful resection of nasal dermoids with intracranial extension by way of a subcranial approach. The patients were 13 months and 19 months old at the time of excision and have been followed for 7 years and 6 years, respectively. There has not been any recurrence of the lesions. There has been no apparent negative impact on facial growth in either of these cases. CONCLUSIONS: The subcranial approach is an effective technique for the resection of nasal dermoids with intracranial extension. These lesions have traditionally been managed with lateral rhinotomy, midface degloving, or external rhinoplasty approaches combined with a frontal craniotomy. The subcranial approach offers excellent exposure, minimizes frontal lobe retraction, reduces the likelihood of cerebrospinal fluid leak, and provides for excellent cosmetic result. This approach was used in two cases with long-term follow-up. The lesions were successfully resected in both cases. Long-term follow-up has shown no recurrence or negative effect on craniofacial growth.

Craniotomy↗

PubMed1997

Matrix metalloproteinase-9 in cerebral aneurysms.

OBJECTIVE: Generalized disruption of arterial wall morphological changes in patients harboring cerebral aneurysms has been documented; however, little is known regarding the pathogenesis of these changes. To explore the role of the elastolytic gelatinase, matrix metalloproteinase-9 (MMP-9), levels of this enzyme in the wall of intracranial aneurysms were compared with those in both intracranial and extracranial arteries. The tissue levels of its major inhibitor, tissue inhibitor of metalloproteinase (TIMP), were measured in these tissues as well. The activity of MMP-9 in plasma was also evaluated. METHODS: The aneurysm wall was excised from three of six patients undergoing craniotomies for aneurysm clipping. A 1-cm segment of superficial temporal artery (STA) was obtained from each of six patients. Additional STAs were obtained from six patients in the control group who were undergoing craniotomies for nonvascular disease. An intracranial artery was also obtained from the anterior temporal neocortical resection of a patient undergoing a craniotomy for mesial temporal sclerosis. MMP-9 and TIMP levels were determined via Western blot analysis. Using substrate gel Zymography, MMP-9 plasma activity was determined for a separate cohort of patients with aneurysms (n = 6) and patients in the control group (n = 6). RESULTS: MMP-9 and TIMP levels in the aneurysm wall were markedly increased beyond levels in both extracranial arteries (STAs from patients with aneurysms and patients in the control group) and the intracranial artery. There were no differences in the levels of MMP-9 in the STAs of patients harboring aneurysms when compared with patients in the control group. Also, no differences were noted in plasma MMP-9 activity. CONCLUSION: Local rather than systemic perturbations in MMP-9 levels may contribute to the matrix disruption associated with cerebral aneurysms. This local up-regulation is not the result of TIMP down-regulation. The lack of increased systemic metalloproteinase activity precludes the use of plasma MMP-9 activity as a screening tool for presymptomatic aneurysms. However, local therapeutic modulation of MMP-9 activity may help arrest aneurysm progression.

Aneurysm, Ruptured↗

PubMed1999

Evaluation of application techniques of fibrin sealant to prevent cerebrospinal fluid leakage: a new device for the application of aerosolized fibrin glue.

OBJECTIVE: This report evaluates the sealing effects of fibrin sealant applied on the dura mater using different techniques. METHODS: Three application methods were studied: a sequential layer method, a simultaneous method using a cannula, and a spray method using a newly developed spray device. The sealing effects of these methods were compared using in vitro histological analysis and a pressure resistance test. The clinical efficacy of the fibrin sealant to prevent water leakage through the dura mater was retrospectively analyzed in a total of 509 patients. The process of absorption of a clinically applied fibrin clot in vivo was examined using surgical specimens. RESULTS: The fibrin plate made using the spray method withstood a hydrostatic pressure greater than 200 cm H2O. A scanning electron microscopic study of the fibrin clots showed that the sequential and simultaneous methods produced a fibrin fiber network; in contrast, our spray method formed a dense fibrin tissue in which the fibrin molecules fused together forming stratified laminae. Of the 295 supratentorial craniotomies during which spraying was used, postsurgical cerebrospinal fluid leakage occurred in 9 cases (3.1%), whereas of the 214 craniotomies during which spraying was not used, cerebrospinal fluid leakage occurred in 19 cases (8.9%). Histological examinations of 10 surgical specimens obtained during second craniotomies revealed that the spray-made fibrin clots had been gradually replaced by mature granulation composed of collagenous connective tissue. CONCLUSION: The optimal technique for applying fibrin sealant is the spray method that aerosolizes fibrin glue and produces a tough fibrin plate.

Administration, Topical↗

PubMed1999

Endoscopic resection of colloid cysts: surgical considerations using the rigid endoscope.

OBJECTIVE: Colloid cysts of the third and lateral ventricles have traditionally been treated by transfrontal and transcallosal microsurgical resection or by stereotactic aspiration. Recently, rigid and flexible ventricular endoscopic techniques have been used to treat these lesions. Our study was undertaken to examine the efficacy of rigid endoscopy in the resection of colloid cysts. METHODS: Fifteen patients with a radiological diagnosis of colloid cysts were given the option of undergoing either endoscopic surgery or craniotomy. The average tumor size was 1.43 cm. Fourteen patients underwent planned endoscopic resections, and a craniotomy was performed initially in one patient. RESULTS: Entire tumor resection was achieved with the endoscope in 12 patients (86%). A craniotomy was required for two colloid cysts that could not be resected endoscopically. In total, complete radiographic resections were achieved in 14 patients (93%). There were no permanent complications, although postoperative deficits included short-term memory loss and hemiparesis, each in one patient. CONCLUSION: Rigid endoscopy affords good optical resolution, high magnification, and excellent illumination. Total or near total resection of colloid cysts should be the goal for all patients and can be achieved using the rigid endoscope, with little morbidity, shortened operative time, reduced length of stay, and resolution of symptoms. Although long-term follow-up is needed, we think that endoscopy should be considered as a primary treatment for most patients.

Adult↗

PubMed2000

Magnetic resonance imaging-guided neurosurgery in the magnetic fringe fields: the next step in neuronavigation.

OBJECTIVE: We describe the development of an alternative approach to intraoperative magnetic resonance imaging (iMR)-guided neurosurgery and report our initial experience with 22 craniotomies and 16 brain biopsies. The advantages and disadvantages of each approach are examined. METHODS: An iMR suite houses a 0.2-T open configuration system (Siemens Medical Systems, Erlangen, Germany) and is equipped with anesthetic gases and a magnetic resonance imaging (MRI)-compatible anesthesia machine and monitor. Standard operating instruments and equipment were tested for safety and compatibility in the magnetic fringe fields surrounding the open MRI system. We then performed brain biopsies and craniotomies in the iMR suite. RESULTS: Standard operating equipment functioned properly in the 0.5- to 10-mT zone and was not affected by the magnet's attractive force. Twenty-two craniotomies and 16 brain biopsies were performed in the interventional suite, using serial intraoperative MRI guidance, without injury to patients or operating room staff. CONCLUSION: Full neurosurgical procedures may be performed in the weak fringe fields surrounding an MRI system, using standard operating room equipment. This approach to iMR-guided neurosurgery offers a significant cost advantage over retrofitting an entire operative suite with "MRI-compatible" surgical equipment. The surgeon's familiarity with standard equipment and the reliability of the equipment are additional advantages. Neurosurgery in the fringe fields allows the neurosurgeon to utilize serial MRI with a minimum of inconvenience, disruption, and change to the standard neurosurgical procedure. Serial intraoperative imaging to visualize the changes in the brain that are associated with neurosurgical intervention seems to enhance the ability to safely and effectively accomplish neurosurgical goals.

Adolescent↗

PubMed2001

Quantitative analysis of the transcondylar approach to the foramen magnum.

OBJECTIVE: Condylar resection with suboccipital craniotomy increases foramen magnum exposure, but guidelines for when this is necessary are not defined. Cadaveric and computed tomography evaluations were completed to guide decision-making regarding the use and extent of condylar resection. METHODS: Quantitative analysis of foramen magnum surgical exposures was performed on 32 skulls (64 sides) and 6 cadaveric dissections (12 sides). Computed tomographic (CT) scans were performed on cadaveric heads before and after condylar resections. Digitized images of dry skulls and CT images of cadaver heads were quantitatively analyzed. Predissection CT measurements of cadaveric heads guided extent of condylar resections, and resection accuracy was assessed with postdissection CT scans. RESULTS: Skull measurements (means in parentheses) included the foramen magnum area (7.8 cm(2)), length (3.6 cm), width (3.1 cm), anteroposterior condylar length (2.3 cm), and axial condylar length (2.5 cm). Mean widths of potential surgical exposures for skulls were obtained for A) suboccipital craniotomy (2.3 cm), B) with 25% (2.6 cm), and C) 50% condylar resection (3.0 cm). Mean angles of exposure were as follows: A, 38.4 degrees; B, 49.1 degrees; and C, 54.3 degrees. CT scans of cadaveric heads before and after dissections yielded measurements of exposure equivalent to measurements found on the dry skulls. CONCLUSION: On average, lateral exposure increases by 3 mm (13%) and 7 mm (30%) for 25 and 50% condylar resection, respectively, compared with suboccipital craniotomy alone. Angles of exposure increase by 10.7 degrees (28%) and 15.9 degrees (41%). Measurements of CT images can be used preoperatively to help analyze the need for condylar resection and intraoperatively to guide the extent of condylar resection.

Adult↗

PubMed2004

Hearing preservation with the transcrusal approach to the petroclival region.

OBJECTIVE: We studied the hearing results and outcomes after transcrusal craniotomy. STUDY DESIGN: We conducted a retrospective review. SETTING: This study was conducted at a tertiary care hospital. PATIENTS: We studied 10 consecutive patients, including two men and eight women, who underwent transcrusal craniotomy for petroclival masses or tumors. INTERVENTION: The intervention consisted of therapeutic removal of petroclival meningioma. MAIN OUTCOME MEASURE: The main outcome measure of this study was hearing preservation as measured by standard audiogram. RESULTS: There were six meningiomas, one eighth nerve schwannoma, one fifth nerve schwannoma, one chordoma, and one midbasilar artery aneurysm. Postoperative hearing was measured according to the AAOHNS criteria. Complications and further therapies were recorded. Postoperative hearing was measured in eight. The cochlear nerve was severed in one patient. One was unavailable for follow up. Eight patients retained hearing at or near preoperative levels, seven with SRT within 10 dB and speech discrimination within 10% of preoperative levels. Four patients presented with trigeminal symptoms, one with third nerve palsy and two with facial weakness. Postoperative deficits included fourth, sixth, seventh, and eighth nerve palsies in three patients. Complications included one wound infection, two cerebrospinal fluid leak, and two cases of meningitis, both of which were sterile. There were secondary procedures in five patients-three radiosurgery, two shunts, one tracheotomy, and one g-tube. CONCLUSIONS: Transcrusal craniotomy is a safe and effective approach to the petroclival region. Excellent hearing results can be expected with this technique.

Adult↗