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Gautam U. Mehta and Gregory P. Lekovic

Although most widely known as the birthplace of neuro-otology, the House Clinic in Los Angeles has been the site of several major contributions to the field of neurosurgery. From the beginning of the formation of the Otologic Medical Group in 1958 (later renamed the House Ear Clinic), these contributions have been largely due to the innovative and collaborative work of neurosurgeon William E. Hitselberger, MD, and neuro-otologist William F. House, MD, DDS. Together they were responsible for the development and widespread adoption of the team approach to skull-base surgery. Specific neurosurgical advances accomplished at the House Clinic have included the first application of the operative microscope to neurosurgery, the application of middle fossa and translabyrinthine approaches for vestibular schwannoma, and the development of combined petrosal, retrolabyrinthine, and other alternative petrosal approaches and of hearing preservation surgery for vestibular schwannoma. The auditory brainstem implant, invented at the House Clinic in 1979, was the first ever successful application of central nervous system neuromodulation for restoration of function. Technological innovations at the House Clinic have also advanced neurosurgery. These include the first video transmission of microsurgery, the first suction irrigator, the first debulking instrument for tumors, and the House-Urban retractor for middle fossa surgery.

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Marc S. Schwartz and Gregory P. Lekovic

OBJECTIVE

The CO2 laser has been used on an intermittent basis in the microsurgical resection of brain tumors for decades. These lasers were typically cumbersome to use due to the need for a large, bulky design since infrared light cannot be transmitted via fiber-optic cables. Development of the OmniGuide cable, which is hollow and lined with an omnidirectional dielectric mirror, has facilitated the reintroduction of the CO2 laser in surgical use in a number of fields. This device allows for handheld use of the CO2 laser in a much more ergonomically favorable configuration, holding promise for microneurosurgical applications. This device was introduced into the authors’ practice for use in the microsurgical resection of skull base tumors, including vestibular schwannomas.

METHODS

The authors reviewed the initial 41 vestibular schwannomas that were treated using the OmniGuide CO2 laser during an 8-month period from March 2010 to October 2010. The laser was used for all large tumors, and select medium-sized tumors were treated via both the translabyrinthine and retrosigmoid approaches. The estimated time of tumor resection and estimated blood loss were obtained from operating room records. Data regarding complications, facial nerve and hearing outcomes, and further treatment were collected from hospital and clinic records, MRI reports, and direct review of MR images. Time of resection and blood loss were compared to a control group (n = 18) who underwent surgery just prior to use of the laser.

RESULTS

A total of 41 patients with vestibular schwannomas were surgically treated. The median estimated time of tumor resection was 150 minutes, and the median estimated blood loss was 300 ml. The only operative complication was 1 CSF leak. Thirty-eight patients had normal facial nerve function at late follow-up. The median MRI follow-up was 52 months, and, during that time, only 1 patient required further treatment for regrowth of a residual tumor.

CONCLUSIONS

The OmniGuide CO2 laser is a useful adjunct in the resection of large vestibular schwannomas. This device was used primarily as a cutting tool rather than for tumor vaporization, and it was found to be of most use for very large and/or firm tumors. There were no laser-associated complications, and the results compared favorably to earlier reports of vestibular schwannoma resection.

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Gregory P. Lekovic, Marc S. Schwartz and John L. Go

In this report the authors report on a patient with a very indolent course of granulocytic sarcoma, characterized by steroid-induced remission of spinal and cranial tumors and recurrence over a period of several years. This 24-year-old man with history of leukemia presented with rapid-onset quadriparesis secondary to multiple extraaxial masses of the cervicothoracic spine, from C-5 to T-3, and lumbosacral spine, from L-5 to the coccyx. Although the imaging features were highly suggestive of neurofibromatosis Type 2, the patient's history and clinical course were consistent with granulocytic sarcoma; repeat imaging and, later, needle biopsy definitively established the diagnosis of granulocytic sarcoma. Laminectomy and surgical decompression of the spine were not required and, arguably, could have posed unnecessary risk to the patient. This case illustrates that the successful management of a patient presenting with profound neurological deficits due to intradural spinal cord tumors may sometimes be nonsurgical.

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Lindsey Ross, Doniel Drazin, Paula Eboli and Gregory P. Lekovic

Object

The authors present a series of 4 patients with rare facial nerve tumors. The relevant literature is reviewed and is discussed regarding diagnostic features, the role of operative management, and surgical approach.

Methods

A retrospective chart review was conducted for patients with tumors of the facial nerve that were treated between 2008 and 2011. Patients undergoing observation with serial MRI and those who were treated with up-front radiosurgery and for whom tissue diagnosis was not available were excluded. In addition, patients with suspected vestibular schwannoma, facial nerve schwannoma, neurofibromatosis Type 2, and metastatic disease were also excluded. The charts of 4 patients (2 men and 2 women) with “atypical” tumors were reviewed and analyzed.

Results

A total of 12 patients with tumors of the facial nerve were identified during the study period. Patient characteristics, preoperative imaging, operative approach, tumor histology, and outcomes are described.

Conclusions

Atypical facial nerve tumors must be distinguished from the more common facial nerve schwannoma. How the authors of this study treat rare facial nerve tumors is based on their experience with the more common facial nerve schwannomas, characterized by a slow progression of symptoms and growth. Less is known about the rare lesions, and thus a conservative approach may be warranted. Open questions include the role of radiosurgery, facial nerve decompression, and indications for resection of tumor and cable grafting for these rare lesions.

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Adam N. Master, Daniel S. Roberts, Eric P. Wilkinson, William H. Slattery and Gregory P. Lekovic

OBJECTIVE

The authors describe their results using an endoscope as an adjunct to microsurgical resection of inferior vestibular schwannomas (VSs) with extension into the fundus of the internal auditory canal below the transverse crest.

METHODS

All patients who had undergone middle fossa craniotomy for VSs performed by the senior author between September 2014 and August 2016 were prospectively enrolled in accordance with IRB policies, and the charts of patients undergoing surgery for inferior vestibular nerve tumors, as determined either on preoperative imaging or as intraoperative findings, were retrospectively reviewed. Age prior to surgery, side of surgery, tumor size, preoperative and postoperative pure-tone average, and speech discrimination scores were recorded. The presence of early and late facial paralysis, nerve of tumor origin, and extent of resection were also recorded.

RESULTS

Six patients (all women; age range 40–65 years, mean age 57 years) met these criteria during the study period. Five of the 6 patients underwent gross-total resection; 1 patient underwent a near-total resection because of a small amount of tumor that adhered to the facial nerve. Gross-total resection was facilitated using the operative endoscope in 2 patients (33%) who were found to have additional tumor visible only through the endoscope. All patients had a House-Brackmann facial nerve grade of II or better in the immediate postoperative period. Serviceable hearing (American Academy of Otolaryngology–Head and Neck Surgery class A or B) was preserved in 3 of the 6 patients.

CONCLUSIONS

Endoscope-assisted middle fossa craniotomy for resection of inferior vestibular nerve schwannomas with extension beyond the transverse crest is safe, and hearing preservation is feasible.

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Scott D. Wait, Brendan D. Killory, Gregory P. Lekovic and Curtis A. Dickman

Object

Palmar, axillary, and plantar hyperhidrosis is often socially, emotionally, and physically disabling for adolescents. The authors report surgical outcomes in all adolescents treated for palmar hyperhidrosis via bilateral thoracoscopic sympathectomy at the Barrow Neurological Institute by the senior author.

Methods

A prospectively maintained database of all adolescent patients undergoing bilateral thoracoscopic sympathectomy between 1998 and 2006 (inclusive) was reviewed. Additional follow-up was obtained as needed in clinic or by phone or written questionnaire.

Results

Fifty-four patients (40 females) undergoing bilateral procedures were identified. Their mean age was 15.4 years (range 10–17 years). Average follow-up was 42 weeks (range 0.2–143 weeks). Hyperhidrosis involved the palms alone in 10 patients; the palms and axilla in 6 patients; the palms and plantar surfaces in 17 patients; and the palms, axilla, and plantar surfaces in 21 patients. Palmar hyperhidrosis resolved completely in 98.1% of the patients. Resolution or improvement of symptoms was seen in 96.3% of patients with axillary and 71.1% of those with plantar hyperhidrosis. Hospital stay averaged 0.37 days with 68.5% of patients discharged the day of surgery. One patient experienced brief intraoperative asystole that resolved with medications and had no long-term sequelae. Otherwise, no serious intraoperative complications occurred. No patient required chest tube drainage. The percentage of patients who reported satisfaction and willingness to undergo the procedure again was 98.1%.

Conclusions

Biportal, bilateral thoracoscopic sympathectomy is an effective and low-morbidity treatment for severe palmar, axillary, and plantar hyperhidrosis.

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Marc S. Schwartz, Gregory P. Lekovic, Derald E. Brackmann and Courtney C. J. Voelker

We present video of gross-total resection of a large cerebellopontine angle tumor consisting of both vestibular and facial schwannoma components via the translabyrinthine route in a patient with neurofibromatosis type 2. The facial nerve is reconstructed using a greater auricular nerve graft, and an auditory brainstem implant is placed. Prior to surgery the patient had no facial nerve function on the operative side and had lost useful hearing. He also had usable vision only on the ipsilateral side and had contralateral vocal cord paralysis.

The video can be found here: http://youtu.be/IOkEND-0vhI.

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Gregory P. Lekovic, L. Fernando Gonzalez, Vini G. Khurana and Robert F. Spetzler

✓Although cavernous malformations (CMs) are an important cause of intracranial hemorrhage, the natural history of these lesions is controversial. Both retrospective and prospective studies undertaken to define risk factors for hemorrhage from CMs have consistently identified the location of a lesion as a factor that has a significant impact on the rate of rupture, and brainstem CMs consistently have a higher rate of symptomatic hemorrhage than those at other locations. The mechanism underlying this disparity in rupture rates, however, remains obscure. Most authors attribute the difference, at least partially, to the sensitivity of the brainstem to hemorrhage. Regardless, the specific factors that cause a given CM to rupture are unknown.

The authors report their first encounter with an intraoperative rupture of a CM in the brainstem. This case underscores the risks encountered during the surgical approach to brainstem CMs and may provide insight into the pathophysiological mechanisms underlying the rupture of these lesions.

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Gregory P. Lekovic, Eric A. Potts, Dean G. Karahalios and Graham Hall

Object

The goal of this study was to compare the accuracy of thoracic pedicle screw placement aided by two different image-guidance modalities.

Methods

The charts of 40 consecutive patients who had undergone stabilization of the thoracic spine between January 2003 and January 2005 were retrospectively reviewed. Three patients were excluded from the study because, on the basis of preoperative findings, small pedicle diameter precluded the use of pedicle screws. Thus, a total of 37 patients had 277 screws placed with the aid of either virtual fluoroscopy or isocentric C-arm 3D navigation. The indications for surgery included trauma, degenerative disease, and tumor, and were similar in both groups. All 37 patients underwent postoperative computed tomography scanning, and an independent reviewer graded all screws based on axial, sagittal, and coronal projections for a full determination of the placement of the screw in the pedicle.

Results

The rate of unintended perforations was found to depend on pedicle diameter (p < 0.0001). There were no statistical differences between groups with regard to rate or grade of cortical perforations. Overall, the rate and grade of perforations was low, and there were no neurological or vascular complications.

Conclusions

The authors have shown that either image-guidance system may be used with a high degree of accuracy and safety. Because both systems were found to be comparably safe and accurate, the choice of image-guidance modality may be determined by the level of surgeon comfort and/or availability of the system.

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Michael Hoa, Doniel Drazin, George Hanna, Marc S. Schwartz and Gregory P. Lekovic

With the increasing prevalence and decreasing cost of MRI scans, incidental discovery of vestibular schwannoma (VS) has become more common. Scarce literature exists regarding management of the tumors in those patients with incidentally discovered VSs, and clear guidelines for management do not exist. In this review, the authors examine the available literature for insights into management of incidentally diagnosed VS and provide an algorithm for their management.