Aaron R. Cutler, Sean W. Kaloostian, Akira Ishiyama and John G. Frazee
Vestibular nerve sectioning is an accepted surgical treatment option for patients with medically refractory Ménière disease. In this paper the authors introduce and evaluate a 2-handed endoscopic-directed technique for vestibular nerve section.
Eleven patients underwent a retrosigmoid craniectomy for endoscopic-directed vestibular nerve sectioning as treatment for intractable vertigo associated with Ménière disease. In all patients, identification and dissection of the cranial nerve VII/VIII complex was performed entirely under endoscopic guidance. The authors used the specially designed Frazee II neuroendoscope, consisting of a traditional endoscope lens with a microsuction attachment.
Vestibular nerve sectioning was completed in all 11 patients. Postoperative improvement in vertiginous episodes was achieved in 10 patients (91%). Auditory function was noted to be worse postoperatively in only 1 patient (9%). The same patient also developed a House-Brackmann Grade III facial nerve palsy, which improved gradually over time. There were no further complications, including no delayed CSF leaks.
The endoscopic-directed approach represents a safe and effective method for performing vestibular nerve sectioning. Until now, the endoscope has been used primarily as an adjunct to the operating microscope in surgery at the cerebellopontine angle. In addition, previous endoscopic techniques typically require a third hand to manipulate the endoscope. With the 2-handed endoscopic-directed technique, however, the endoscope is used as the primary means of visualization, and the unique design of this endoscope allows for a bimanual procedure without the requirement of a cosurgeon. Advantages of using this technique compared with the microscope include superior brightness at close distances, greater depth of field, increased maneuverability within small regions, and an improved ability to visualize objects not in a direct line of sight. Among other things, this allows for minimally invasive openings, decreased cerebellar retraction, and better identification of nerve cleavage planes and vascular anatomy.
Aaron R. Cutler, Saquib Siddiqui, Mohan Avinash L., Virany H. Hillard, Franco Cerabona and Kaushik Das
Transforaminal lumbar interbody fusion (TLIF) is an accepted alternative to circumferential fusion of the lumbar spine in the treatment of degenerative disc disease, spondylolisthesis, and recurrent disc herniation. To maintain disc height while arthrodesis takes place, the technique requires the use of an interbody spacer. Although titanium cages are used in this capacity, the two most common spacers are polyetheretherketone (PEEK) cages and femoral cortical allografts (FCAs). The authors compared the clinical and radiographic outcomes of patients who underwent TLIF with pedicle screw fixation, in whom either a PEEK cage or an FCA was placed as an interbody spacer.
The charts and x-ray films obtained in 39 patients (age range 33–68 years, mean 44.7 years) who underwent single-level TLIF between October 2001 and April 2004 and in whom either a PEEK cage (18 patients) or FCA (21 patients) was placed as an interbody spacer were evaluated in a retrospective study. Radiological outcome was based on fusion rate and a comparison of the initial postoperative lordotic angle on standing lateral radiographs with that at long-term follow up (mean follow up 15.1 months, minimum 12 months). To control for variations in radiographic magnification, the authors used lordotic angle as an indirect measure of disc space height. Clinical outcome was assessed using the Oswestry Disability Index (ODI).
There were no major complications in either group. Radiographically documented fusion occurred in all patients in the PEEK group and 95.2% of those in the FCA group. Pseudarthrosis developed in one patient in the FCA group, and this patient underwent additional surgery. In both groups, the mean lordotic angle changed by less than 2.20° during the postoperative period, and the mean postoperative ODI score was more than 40 points lower than the mean preoperative score. There was no significant difference between the two groups in mean change in lordotic angle (p = 0.415) and mean change in ODI score (p = 0.491).
Both PEEK cages and FCAs are highly effective in promoting interbody fusion, maintaining postoperative disc space height, and achieving desirable clinical outcomes in patients who undergo TLIF with pedicle screw fixation. The advantages of PEEK cages include a lower incidence of subsidence and their radiolucency, which permits easier visualization of bone growth.