A subset of patients with Chiari Type I malformation may develop neurological dysfunction secondary to an abnormally obtuse clivoaxial angle (CXA) and clivoaxial deformity causing deformative stress injury to the neural axis. Clivoaxial deformity can occur after initial standard suboccipital craniectomy, duraplasty, and C-1 laminectomy for brainstem compression, or severe clivoaxial deformity may be present in conjunction with a Chiari malformation. Clivoaxial deformity and abnormal CXA can be treated with an occipitocervical fusion (OCF). Performing OCF in the setting of a cranial defect can be challenging with currently available instrumentation. The authors describe their recent experience and outcomes in 3 consecutive pediatric patients using the “inside-out” technique for treating clivoaxial deformity and abnormal CXA in the setting of a craniectomy defect to restore stability to the craniocervical junction, while correcting the CXA.
Daniel Felbaum, Steven Spitz and Faheem A. Sandhu
Steven M. Spitz, Faheem A. Sandhu and Jean-Marc Voyadzis
Percutaneous pedicle screws are used to provide rigid internal fixation in minimally invasive spinal procedures and generally require the use of Kirchner wires (or K-wires) as a guide for screw insertion. K-wires can bend, break, advance, or pull out during the steps of pedicle preparation and screw insertion. This can lead to increased fluoroscopic and surgical times and potentially cause neurological, vascular, or visceral injury. The authors present their experience with a novel “K-wireless” percutaneous pedicle screw system that eliminates the inherent risks of K-wire use.
A total of 100 screws were placed in 28 patients using the K-wireless percutaneous screw system. Postoperative dedicated spinal CT scans were performed in 25 patients to assess the accuracy of screw placement. Screw placement was graded A through D by 2 independent radiologists: A = within pedicle, B = breach < 2 mm, C = breach of 2–4 mm, and D = breach > 4 mm. Screw insertion and fluoroscopy times were also recorded in each case. Clinical complications associated with screw insertion were documented.
A total of 100 K-wireless percutaneous pedicle screws were placed into the lumbosacral spine in 28 patients. Postoperative CT was performed in 25 patients, thus the placement of only 90 screws was assessed. Eighty-seven screws were placed within the pedicle confines (Grade A), and 3 violated the pedicle (2 Grade B [1 lateral, 1 medial] and 1 Grade D [medial]) for an overall accuracy rate of 96.7%. One patient required reoperation for screw repositioning due to a postoperative L-5 radiculopathy secondary to a Grade D medial breach at L-5. This patient experienced improvement of the radiculopathy after reoperation. Average screw insertion and fluoroscopy times were 6.92 minutes and 22.7 seconds per screw, respectively.
The results of this study demonstrate that the placement of K-wireless percutaneous pedicle screws is technically feasible and can be performed accurately and safely with short procedure and fluoroscopy times.
Mark C. Spitz, Ken R. Winston, Edward H. Maa and Steven G. Ojemann
Discontinuity in the silicone insulation over an electrode of a left vagus nerve stimulator (VNS) allowed the aberrant leak of current to the phrenic nerve and other structures. This resulted in ipsilateral diaphragmatic dysfunction, inability to vocalize, and severe radiating pain into the jaw and upper incisor for the duration of each stimulation. The device was explanted and a new device was implanted. All stimulation-related symptoms ceased immediately.
A similar discontinuity in the silicone insulation is the likely explanation for several prior reports of poorly understood pains and phrenic nerve stimulation in patients with VNSs. The findings and analysis of this case establish a rationale for consideration of replacement of the VNS lead in all similarly symptomatic patients.
Steven M. Grunberg, Martin H. Weiss, Irving M. Spitz, Jamshid Ahmadi, Alfredo Sadun, Christy A. Russell, Lois Lucci and Lani L. Stevenson
✓ The possibility that meningioma growth may be related to female sex hormone levels is suggested by several lines of evidence. Meningiomas are twice as common in women as in men, have been observed to wax and wane with pregnancy, and are positively associated with breast cancer. A physiological explanation for these phenomena is provided by the finding of steroid hormone receptors in meningiomas. However, unlike breast cancer, meningiomas are much more commonly positive for progesterone receptors than for estrogen receptors.
The authors initiated a study on long-term oral therapy of unresectable meningiomas with the antiprogesterone mifepristone (RU486). Fourteen patients received mifepristone in daily doses of 200 mg for periods ranging from 2 to 31+ months (≥ 6 months in 12 patients). Five patients have shown signs of objective response (reduced tumor measurement on computerized tomography scan or magnetic resonance image, or improved visual field examination). Three have also experienced subjective improvement (improved extraocular muscle function or relief from headache). The side effects of long-term mifepristone therapy have been mild. Fatigue was noted in 11 of the 14 patients. Other side effects included hot flashes in five patients, gynecomastia in three, partial alopecia in two, and cessation of menses in two. Long-term therapy with mifepristone is a new therapeutic option that may have efficacy in cases of unresectable benign meningioma.
Rory J. Petteys, Steven M. Spitz, C. Rory Goodwin, Nancy Abu-Bonsrah, Ali Bydon, Timothy F. Witham, Jean-Paul Wolinsky, Ziya L. Gokaslan and Daniel M. Sciubba
Renal cell carcinoma (RCC) frequently metastasizes to the spine, causing pain or neurological dysfunction, and is often resistant to standard therapies. Spinal surgery is frequently required, but may result in high morbidity rates. The authors sought to identify prognostic factors and determine clinical outcomes in patients undergoing surgery for RCC spinal metastases.
The authors searched the records of patients who had undergone spinal surgery for metastatic disease at a single institution during a 12-year period and retrieved data for 30 patients with metastatic RCC. The records were retrospectively reviewed for data on preoperative conditions, treatment, and survival. Statistical analyses (i.e., Kaplan-Meier survival analysis and log-rank test in univariate analysis) were performed with R version 2.15.2.
The 30 patients (23 men and 7 women with a mean age of 57.6 years [range 29–79 years]) had in total 40 spinal surgeries for metastatic RCC. The indications for surgery included pain (70%) and weakness (30%). Fourteen patients (47%) had a Spinal Instability Neoplastic Score (SINS) indicating indeterminate or impending instability, and 6 patients (20%) had a SINS denoting instability. The median length of postoperative survival estimated with Kaplan-Meier analysis was 11.4 months. Younger age (p = 0.001) and disease control at the primary site (p = 0.005), were both significantly associated with improved survival. In contrast, visceral (p = 0.002) and osseous (p = 0.009) metastases, nonambulatory status (p = 0.001), and major comorbidities (p = 0.015) were all significantly associated with decreased survival. Postoperative Frankel grades were the same or had improved in 78% of patients. Major complications occurred in 9 patients, and there were 3 deaths (10%) during the 30-day in-hospital period. Three en bloc resections were performed.
Resection and fixation may provide pain relief and neurological stabilization in patients with spinal metastases arising from RCC, but surgical morbidity rates remain high. Younger patients with solitary spinal metastases, good neurological function, and limited major comorbidities may have longer survival and may benefit from aggressive intervention.