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Vol 10 No 1 Archive

Presentation Abstracts: Presentation Authors O-P

ANTERIOR KEY-HOLE APPROACH TO MEDIAL ORBITAL APEX AND OPTIC CANAL LESIONS (ANATOMIC AND OPERATIVE CORRELATIONS)

Serge Obukhov, MD, PhD (presenter), Howard R. Krauss, MD, Donald D. Becker, MD (Los Angeles, USA)

Introduction: Anterior key-hole approach to medial orbital apex and optic canal lesions is a modification of the transbasal approach of Duroma. Limited frontal osteotomy combined with partial ethmoidectomy and medial orbital wall drilling provide shortest access to medial orbital structures and optic canal without frontal lobe retraction.

Methods: Formalin injected cadaveric heads were used to study anterior frontal approach to medial orbital apex and optic canal. Different modifications of transbasal approach of Duroma were used in order to evaluate surgical trajectories to medial orbital apex.

Results: The anterior key-hole approach lesions provides adequate surgical access to medial orbital apex and optic canal. This approach successfully used to treat a patient with an acute visual deterioration due to medial orbital solitary fibrous tumor with a smooth muscle cell component.

Conclusion: Anterior key-hole approach to medial orbital apex and optic canal lesion yields an excellent surgical exposure with views of the optic canal and optic nerve.

NEW APPROACH TO PETROUS APEX GRANULOMAS USING TRANSORAL ROUTE AND IMAGE-GUIDANCE

Serge Obukhov, MD, PhD (presenter), Akira Ishiama, MD (Los Angeles, USA)

Introduction: Petrous apex abscesses or granulomas are traditionally treated by craniotomy using skull base techniques, or by infracochlear drainage procedure. Both techniques regardless of their complexity have significant recurrence and complication rates. A transoral approach with the help of image-guidance could be a simple and safe surgical alternative.

Methods: The procedure was initially performed on a cadaveric head with the help of image-guidance. A 1.5mm blunt trocar was navigated using a transoral route into the petrous portion of the temporal bone. The trajectory was chosen from the tip of petrous apex, behind and parallel to the petrous portion of the carotid artery up to the medial wall of internal meatus. This approach was used on one patient who had suffered of intractable headaches due to petrositis.

Results: One patient has been treated by transoral approach with the help of image-guidance so far. Her symptoms completely resolved within three weeks after surgery.

Conclusion: Transoral approach to the petrous apex with the help of image-guidance is a simple and safe procedure. Further clinical experience will be required to prove whether it can be routinely recommended for drainage of lesions around petrous apex.

SURGICAL TREATMENT, RESULTS AND LONG-TERM FOLLOW-UP STUDY OF TUBERCULUM SELLAE MENINGIOMAS

Kohei Ohta, MD (presenter), Kensaku Yasuo, MD, Masashi Morikawa, MD, Tatsuya Nagashima, MD, Norihiko Tamaki, MD (Kobe, JAPAN)

Object: Surgical techniques, their results of tuberculum sellae meningiomas were studied in a view of a long-term follow-up.

Materials and Methods: Thirty-three cases were operated from 1980 to 2000 and analyzed. There were 4 men and 29 women with an average age of 46.7 years. Eight cases underwent re-operations. The mean follow-up was 10.7 years. Surgical approaches were pterional for 15 patients, FOZ/FO for 10, bilateral subfrontal for 6 and others for 2. Simpson grade (I, II, III, IV) were 12, 9, 0, and 12 cases respectively. Postoperative neurological changes were checked and assessed in terms of the degree of improvement in visual acuity and/or visual field. They were classified into three groups. For this study, the records and clinical data of these cases were retrospectively analyzed.

Results: (1) Recurrence rates were 0% for grade I, 11.1% for grade II and 58.3% for grade IV. (2) The FOZ/FO approach resulted in a lower Simpson grade (p <0.05), but other factors such as age, pathological classification were not related to Simpson grade. (3) Postoperative neurological changes of total removal group (Simpson grade I and II) were improvement (42.9%), no change (42.9%), deterioration (14.3%). In subtotal removal group (Simpson grade IV), the results were improvement (41.7%), no change (50.0%), deterioration (8.3%). The postoperative visual outcome did not depend on total or subtotal removal.

Conclusions: (1) Radical removal of the tumors may result in lower recurrence rate without increasing surgical complications. (2) Those skull base approaches can improve the rate of radical removal of tuberculum sellae meningiomas. Removal of invaded dura and bone, and an opening of an optic canal were effective to improve radicality, evermore important to achieve total removal.

LARYNGEAL REHABILITATION AFTER SKULL BASE CRANIAL NERVE RESECTION

Garth T. Olson, MD (presenter), Mumtaz J. Khan MD, Cheryl Billante Ph.D, James L. Netterville MD (Nashville, USA)

Major morbidity often results from the loss of cranial nerve (CN) functions - after skull base resections. In particular deglutition, phonation, and airway protection may be affected by CN IX, X, XII loss. For laryngeal rehabilitation in these patients, we have performed silastic medialization both with and without arytenoid adduction. The use of this technique is well described for lower CN X loss, however, it's objective efficacy for rehabilitation after skull based resection has not been established.

We have performed laryngeal rehabilitation surgery on 83 patients who have undergone skull base resection between 1/1/89 and 1/1/2000 in the form of silastic medialization(SM) both with and without arytenoid adduction(AA). A subset of these patients had SM performed at the time of skull base resection. The remaining patients underwent SM with or without AA in a delayed fashion. In these patients the addition of AA to SM was a decision made at the time of surgery by the senior author based on the intra-operative voice quality with medialization alone

When we compared the pre-operative objective voice tests with post-operative voice data from those patients with complete documentation and testing, we found significant improvement in all objective vocal measurements. Post-operative voice data also compared favorably to age and gender matched controls. We also documented improved swallowing function in patients who had undergone delayed surgery. These results indicate that SM with or without AA is a successful means to improve laryngeal function after CN loss at the skull base.

MIDDLE FOSSA SKULL BASE APPROACH

Kazim Oner, MD (presenter), Izzet Ovul, Tayfun Kirazli, Cem Bilgen (Bornova Izmir, TURKEY)

Middle fossa skull base approach is an effective surgical technique in accessing to the lesions located in the petrous apex and within the internal auditory canal. This technique was first used by Hartley in 1891. This technique, which saves hearing, has been used in the removal of intracanalicular tumors, cholesterol granulomas, cholesteatomas, petrous apex meningiomas and the repair of facial nerve.

Nine patients, operated on with this technique were reviewed. There were 5 females and 4 males. The patients ranged in age from 19 to 48. The mean age of the patients was 39 years. This technique was used for cholesterol granuloma and cholesteatoma in 5, intracanalicular acoustic neurinoma in 2, neurinoma of the facial nerve in 1 and parotid tumor in 1 patient. The follow-up of the patients ranged from 8 months to 4 years. There were no mortalities.

Middle fossa skull base approach is an effective and safe surgical technique. Advantages and disadvantages of this technique will be discussed with the relevant literature.

PTERIONAL-EXTRADURAL (DOLENC'S) APPROACH FOR TRIGEMINAL SCHWANNOMAS

Necmettin Pamir, MD (presenter), Ugur Ture, MD (Istanbul, TURKEY)

Object: Trigeminal schwannomas are uncommon benign tumors arises from the schwann cell of the trigeminal nerve. They account for less than 0.5% of all intracranial tumors and about 1% to 8% of intracranial schwannomas. Although these tumors are histopathologically benign, because of their anatomical localization, they represent a challenge for surgical removal. In this study we report our experience in surgical treatment of trigeminal schwannomas. Surgical results are compared with the neuroradiological outcomes in the light of literature.

Methods: From August 1994 to November 2000, 10 patients with trigeminal schwannoma were operated in our institution. Patients' ages were ranging between 26 and 64, and the mean was 46.3.

Results: Out of these 10 patients, 9 were operated with the pterional-extradural (Dolenc's) approach; one was operated with the retromastoid approach. In the cases we used Dolenc's approach, surgical removal of the tumor was total whereas in the case we used retromastoid approach, removal was subtotal. There was no surgical morbidity and mortality.

Conclusions: Radical surgical resection of trigeminal schwannoma is the treatment of choice to achieve cure and prevent recurrence. We found that Dolenc's approach is the proper choice for total tumor removal because it enables a surgeon to explore both supratentorial and infratentorial compartments.

ACOUSTIC NEUROMA: POST-SURGICAL PSYCHOSOCIAL AND SOCIOECONOMIC IMPACT ON PATIENTS AND THEIR CAREGIVERS

Neety Panu, BSc (presenter), David W. Rowed, MD, FRCSCS (Toronto, CANADA)

The objective of this study was to investigate the impact of acoustic neuroma surgery on activities of daily living, psychological, employment, and economic facets of the life of the patient and the patient's primary caregiver, an impact that has received little previous attention. This study attempts to discover predictors of postoperative impact from preoperative variables (age, sex, tumour size, and surgical approach). A postal survey was sent to acoustic neuroma patients treated at Sunnybrook and Women's College Health Sciences Centre, Toronto, Canada, between 1990 and 1999. One hundred fifty patients (87%) and 112 caregivers (100% of identified caregivers) responded. Patients and caregivers were negatively affected in many parameters assessed, but these effects could not be reliably predicted from preoperative variables. Caregivers for both positively and negatively affected patients showed higher levels of incapacity than patients not affected by the surgery. Patients and, especially their caregivers should be prepared and informed preoperatively regarding the consequences of surgery on their quality of life.

TRANSPETROUS SURGICAL MANAGEMENT OF POSTERIOR FOSSA MENINGIOMAS

Roberto Pareschi, MD (presenter), Domenico Destito, MD, Aldo Falco Raucci, MD (Legnano, ITALY)

We report our experience and results in the transpetrous surgical treatment of 22 posterior fossa meningiomas. These cases were operated on between 1993 and 2000 and represented 10% of all 235 surgical treated posterior fossa tumors. According to the site of tumor attachment these tumors were divided in cerebellopontine angle (10), posterior petrous (5), petroclival (4), foramen magnum (1), Jugular foramen (2). In 21 patients total removal was achieved, and subtotal in one. Various transpetrous surgical approaches were selected on the tumor location and extension. A petroccipital trans-sigmoid approach was employed in 8 patients, a translabyrinthine route in 9, a transcochlear approach in 4 and a far lateral in 1. No patient died. 15 patients (70%) had facial function House grade I a year postoperatively and 17 (78%) a total or subtotal postoperative deafness. In conclusion the transpetrous approaches appear to be safe method with a very low morbidity rate for surgical management of posterior fossa meningiomas.

MANAGEMENT OF GLOMUS JUGULARE TUMOURS: A REVIEW OF 42 CASES

Roberto Pareschi, MD (presenter), Domenico Destito, MD, Aldo Falco Raucci, MD (Legnano, ITALY)

The management of patients with glomus jugulare tumours presents a difficult test for the surgeon. In this paper, we present our results by reviewing a series of 42 patients observed at the ENT department of Legnano from January 1993 to December 1999: the mean age of presentation was 42 years. 30 (70%) of the patients were female. The most common clinical presentation were those of tinnitus, hearing loss, hoarseness and dysphagia. Seven (19%) of the patients had cranial nerve paralysis preoperatively.

Treatment modalities were surgery alone in 33 cases, radiotherapy alone in 4 patients and combined modalities in 3. 2 patients were not treated. There were no deaths. Postoperative major neurological complications included one stroke. CSF leaks and meningitis were absent. Rehabilitation surgery included vocal cord augmentation, facial nerve grafting and palpebral reanimation in 20 patients.

TRANSFRONTAL SINUS APPROACH: SURGICAL TECHNIQUE AND INDICATIONS

Jaechan Park, MD (presenter), Murali Guthikonda, MD (Detroit, USA)

The transfrontal sinus approach is optimal for the lesions behind the frontal sinus. The scope of the exposure includes midline structures of the anterior cranial fossa from the frontal sinus to the tuberculum sellae and the paramedian structures including the medial orbits. The exposure may be extended with adjacent frontal craniotomy without additional frontal burr holes.

We present 6 cases treated by the transfrontal sinus approach to define indications and advantages of the approach. Extradural neoplasms such as papilloma or adenocarcinoma involving the cribriform plate from the ethmoidal and maxillary sinuses, intradural neoplasms like tuberculum sellae meningioma, orbital pathology, and CSF rhinorrhea are treated by the approach. The approach provides superior cosmetic result, minimal brain retraction, the best frontal sinus control, and the minimal dural separation resulting in lower incidence of pneumocephalus.

The transfrontal sinus approach is done by the following steps: bicoronal or bilateral brow-glabella incision; cutting through the anterior wall of the frontal sinus along the perimeter of the X-ray template with an oscillating saw; removal of the mucosa in the frontal sinus and the nasofrontal duct; removal of the posterior wall of the frontal sinus; removal of the crista galli, section of the olfactory fibers, and closing the adjacent dura to approach extradural lesions in the frontal base; Dural incision along the frontal base to approach intradural lesions; fixation of the anterior wall of the frontal sinus with ablation of the frontal sinus and the nasofrontal duct.

INTRA-OPERATIVE ENDOSCOPY/IMAGE FUSION AND ANGIOGRAPHY IN THE MANAGEMENT AND EVALUATION OF SURGICAL ANEURYSM CLIPPING

Atul Patel, MD (presenter), Amin B. Kassam, MD, Michael Horowitz, MD, Ricardo Carrau, MD, Carl Snyderman, MD, Greta Seever, BSN (Pittsburgh, USA)

Intraoperative endoscopy provides for angled visualization around critical structures, while microscopy provides breath of field, superior magnification and illumination and three dimensional imagery. Combined these two modalities while retaining binocular visualization (image fusion) provides the benefits of both. We in this review we assessed the role of image fusion retrospectively during microsurgical aneurysm repair.

Prospective and retrospective studies have demonstrated a 10 - 15% unexpected anatomic finding following aneurysm clipping (residual fundus or neck, occluded/stenosed efferent or afferent vessel) based on post-operative angiography. While post-surgical angiography remains the gold standard for evaluating the efficacy of aneurysm clipping this procedure is less than ideal. Intra-operative angiography requires portable digital equipment, technologist and radiologist support, and radiographic head holders. In addition, intra-operative angiography adds a small degree of risk and financial cost to the overall operative procedure. Post-operative angiography alone does not provide the surgeon with information in a timely fashion. If unexpected findings are revealed the patient either needs to return to the operating room for a repeat procedure or suffers the sequela of an inadequate clipping (ischemic stroke, aneurysm rupture).

We have begun to explore the applicability of intra-operative image fusion to assist with surgical clipping of aneurysms. Fifty patients were studied with intra-operative or post-operative angiography alone (no endoscopy performed). Of these ten percent incidence of inadequate, unexpected aneurysm clipping was encountered. Fifty patients were studied with intra-operative or post-operative angiography along with intra-operative image fusion. Four patients had there clips repositioned based upon image fusion findings. No unexpected incomplete clippings or vessel occlusions/stenoses were found in these fifty patients on follow-up angiography.

Image fusion/endoscopy is a useful technique that allows a surgeon to clip aneurysm more completely. It may well obviate the need for angiography post aneurysm clipping.

FIBRIN SEALANTS IN SKULL BASE SURGERY. EXPERIENCE IN 74 PATIENTS USING TISSEEL AUGMENTED RECONSTRUCTION

Atul Patel, MD (presenter), Amin B. Kassam, MD, Michael Horowitz, MD, Ricardo Carrau, MD, Carl Snyderman, MD, William Welch, MD, Greta Seever, RN (Pittsburgh, USA)

For more than twenty years fibrin sealant (FS) have been widely used for various neurosurgical indications in Europe, Japan, and to a lesser extent in North America. Primary indications have been dural closures and/or reinforcement, nerve repair, and hemostasis. A variety of FS have been employed with two main distinctions: autologous preparations (A home brews) and prepared pharmaceuticals. Each of these forms of FS carries with it concerns of cost, potential viral transmission, and most recently the development of antibodies to components. Given these concerns we sought to examine the benefits of the use of FS in skull base surgery.

A retrospective case-control cohort study was conducted to assess the efficacy of Tisseel (Baxter Corporation) used in patients undergoing cranial base surgery (CBS) between May 1999 and September 1999. A historical cohort group was created by searching the CBS database for the previous one year period.

The incidence of cerebral spinal fluid leak (CSF) in the Tisseel group was 1.35% while the control group had a leak rate of 4.4%. The only leak in the Tisseel group occurred with an anterior cranial base approach whereas the CSF leaks in the historical control groups were almost evenly distributed among anterior and retromastoid approaches. There were no tension pneumocranium in the Tisseel group while there were two in the historical control group representing a 1.1% rate.

COMPUTED TOMOGRAPHIC ANGIOGRAPHY IN SKULL BASE SURGERY: A REVIEW OF FIFTY CASES

Atul Patel, MD (presenter), Amin Kassam, MD, Michael B. Horowitz, MD, Carl Snyderman, MD, Melanie Fukui, MD, Ricardo Carrau, MD, William Welch, MD (Pittsburgh, USA)

Understanding the relationship of arterial structures relative to bony anatomy is paramount in cranial base surgery. In addition to being invasive, intraarterial angiography has several other disadvantages including inability to simultaneously show vascular structures, pathology and bony structures. Computed Tomographic Angiography (CTA) can overcome all these deficits and when married with neuronavigation systems has the potential of optimizing understanding of these critical anatomic relationship. We sought to examine our experience using CTA for cranial procedures with fifty cases over a two-year period.

FORESTIER'S DISEASE ASSOCIATED WITH A RETRO-ODONTOID MASS CAUSING CERVICOMEDULLARY COMPRESSION

Naresh P. Patel, MD (presenter), J. Patrick Johnson, MD, William W. Choi, MD, Neill M. Wright, MD, Duncan Q. Mcbride (Los Angeles, USA)

Introduction: Forestier's Disease (FD) is a progressive skeletal disorder characterized by massive anterior longitudinal ligament calcification forming a bridge on the anterior border of the thoracic and subaxial cervical spine. To our knowledge, retro-odontoid masses associated with FD have not been described.

Methods: Five patients with FD were treated for retro-odontoid masses and cervicomedullary compression. All patients had progressive neurological symptoms due to ventral compression of the cervicomedullary junction.

Results: Four patients underwent combined transoral resection of the ligamentous mass followed by an occipitocervical fusion procedure. One patient with circumferential cervicomedullary compression underwent a posterior decompression and occipitocervical fusion. Follow-up ranged from 4 to 19 months and four patients had variable neurological improvement. One patient died three weeks postsurgery due to pulmonary complications.

Conclusions: This previously undescribed entity should be considered for patients with FD presenting with progressive quadriparesis. Transoral decompression followed by posterior fusion is typically warranted.