Cyberknife radiosurgery for trigeminal neuralgia treatment: a preliminary multicenter experience.

OBJECTIVE: Radiosurgery has gained acceptance as a treatment option for trigeminal neuralgia. We report our preliminary multicenter experience treating trigeminal neuralgia with the CyberKnife (Accuray, Inc., Sunnyvale, CA). METHODS: A total of 95 patients were treated for idiopathic trigeminal neuralgia between May 2002 and October 2005. Radiosurgical dose and volume parameters were retrospectively analyzed in relation to pain response, complications, and recurrence of symptoms. Optimal treatment parameters were identified for patients who had excellent and sustained pain relief with no complications, including severe or moderate hypesthesia. RESULTS: Excellent pain relief was initially experienced by 64 out of 95 patients (67%). The median time to pain relief was 14 days (range, 0.3-180 d). Posttreatment numbness occurred in 45 (47%) of the patients treated. Using higher radiation doses and treating longer segments of the nerve led to both better pain relief and a higher incidence of hypesthesia. The presence of posttreatment numbness was predictive of better pain relief. The overall rate of complications was 18%. At the mean follow-up time of 2 years, 47 of the 95 patients (50%) had sustained pain relief, all of whom were completely off pain medications. CONCLUSION: The results of this study suggest the following optimal radiosurgical treatment parameters for treatment of idiopathic trigeminal neuralgia: a median maximal dose of 78 Gy (range, 70-85.4 Gy) and a median length of the nerve treated of 6 mm (range, 5-12 mm).

The safety of instrumented outpatient anterior cervical discectomy and fusion.

BACKGROUND CONTEXT: Reported hospitalization times after an anterior cervical discectomy and fusion (ACDF) procedure range between 20 hours to 4 days. Reasons for this wide variation are manifold, but the safety of an instrumented ACDF in the setting of a hostile medical-legal climate is most likely the primary concern influencing such a discrepancy. PURPOSE: The purpose of this study was to evaluate the safety and feasibility of performing single, two- and three-level ACDF with instrumentation on an outpatient or 23-hour observation period basis in order to potentially diminish the additional cost of hardware without compromising the purported benefits of surgery. STUDY DESIGN/SETTING: A retrospective chart review of patients undergoing instrumented ACDF on an outpatient basis was performed. PATIENT SAMPLE: A total of 103 patients with neck pain and/or radiculopathy undergoing ACDF were enrolled into this study. OUTCOME MEASURES: Included the evaluation of intraoperative and perioperative complications, which were reported for a total of 6 months after surgery. Clinical examination and radiographical assessment, including plain radiographs and computed tomography and magnetic resonance imaging (when required), were performed to assess complications. METHODS: Complications were divided into two groups: major and minor. Major complications included vertebral fracture and dehydration resulting in readmission. Minor complications included allergic reactions to medications that did not require hospitalization, and transient (< or = 3 months) neurologic deficit. A comprehensive literature search and meta-analysis was performed to generate a large comparison group in order to compare the complication rates in our outpatient series to those reported in the literature. RESULTS: A total of 99 patients (96.1%) undergoing single and two-level ACDF were discharged less than 15 hours after their surgeries (median time: 8 hours; range: 2-15 hours), and 4 patients (3.9%) were discharged after a 23-hour observation period following three-level ACDF. The overall complication rate in our outpatient series was 3.8% (n=4), including 1.9% (n=2) major and 1.9% (n=2) minor complications. The overall complication rate in the 633 patient meta-analysis derived comparison group was 0.95% (n=6). The difference between overall complication rates was not found to be significantly different (p = .12). The hardware-related complication rate in the meta-analysis comparison group was 0.5% (n=3), and was not found to be significantly different from our rate of 0% (p < or = 1). CONCLUSION: Performing ACDF with instrumentation on an outpatient basis is feasible, and it is not associated with higher overall or hardware-related complication rates as compared with complication rates reported in the literature, suggesting that this procedure is safe to perform on an outpatient basis.

Perioperative complications in transforaminal lumbar interbody fusion versus anterior-posterior reconstruction for lumbar disc degeneration and instability.

OBJECTIVES: Multiple different approaches are used to treat lumbar degenerative disc disease and spinal instability. Both anterior-posterior (AP) reconstructive surgery and transforaminal lumbar interbody fusion (TLIF) provide a circumferential fusion and are considered reasonable surgical options. The purpose of this study was to quantitatively assess clinical parameters such as surgical blood loss, duration of the procedure, length of hospitalization, and complications for TLIF and AP reconstructive surgery for lumbar fusion. METHODS: A retrospective analysis was completed on 167 consecutive cases performed between January 2002 and March 2004. TLIF surgical procedure was performed on 124 patients, including 73 minimally invasive and 51 open cases. AP surgery was performed on 43 patients. Patients were treated for painful degenerative disc disease, facet arthropathy, degenerative instability, and spinal stenosis. RESULTS: The mean operative time for AP reconstruction was 455 minutes, for minimally invasive TLIF 255 minutes, and open TLIF 222 minutes. The mean blood loss for AP fusion surgery was 550 mL, for minimally invasive TLIF 231 mL, and open TLIF 424 mL. The mean hospitalization time for AP reconstruction was 7.2 days, for minimally invasive TLIF 3.1 days, and open TLIF 4.1 days. The total rate of complications was 76.7% for AP reconstruction, including 62.8% major and 13.9% minor complications. The minimally invasive TLIF patients group had the total 30.1% rate of complications, 21.9% of which were minor and 8.2% major complications. There were no major complications in the open TLIF patients group, with 35.3% minor complications. CONCLUSIONS: AP lumbar interbody fusion surgery is associated with a more than two times higher complication rate, significantly increased blood loss, and longer operative and hospitalization times than both percutaneous and open TLIF for lumbar disc degeneration and instability.

Utility of computerized isocentric fluoroscopy for minimally invasive spinal surgical techniques.

OBJECTIVE: The purpose of this study was to prospectively evaluate the clinical utility and accuracy of intraoperative three-dimensional fluoroscopy as an adjunct for the placement of a complex spinal instrumentation. METHODS: The Siemens Iso-C three-dimensional fluoroscopy unit in the combination with the Stealth Treon computer volumetric navigational system was used. A total of 279 spinal instrumentation screws or transpedicular cannulations were performed in 69 patients. Accuracy, operative time, and amount of fluoroscopy utilization time were assessed for transforaminal lumbar interbody fusion (TLIF) and kyphoplasty cases. RESULTS: Only 4 percutaneous transpedicular lumbar screws out of 265 total (1.5%) were malpositioned. Average operative time for TLIF cases was 185 minutes (range 114-311 minutes) for one-level and 292.6 minutes (range 173-390 minutes) for two-level procedures. Biplanar fluoroscopy utilization time was 93 seconds (range 27-280 seconds) for one-level procedures and 216 seconds (range 80-388 seconds) for two-level procedures. Average surgery duration for kyphoplasty was 60 minutes (range 36-79 minutes) for one-level procedures and 68.5 minutes (range 65-75 minutes) for two-level cases. Biplanar fluoroscopy utilization time was 41.3 seconds per case (range 25-62 seconds). CONCLUSIONS: Use of intraoperative three-dimensional fluoroscopy for image guidance in minimally invasive complex spinal instrumentation procedures is feasible and safe. This technique provides excellent visualization of three-dimensional relationships. This potentially results in improved accuracy of screw positioning and the ability to detect misplaced screws prior to wound closure. This technique also potentially results in a significant reduction in radiation exposure for both the patient and the staff.

CyberKnife radiosurgery for idiopathic trigeminal neuralgia.

OBJECT: Gamma knife surgery is an accepted treatment option for trigeminal neuralgia (TN). The safety and efficacy of CyberKnife radiosurgery as a treatment option for TN, however, has not been established. METHODS: Forty-one patients were treated between May 2002 and September 2004 for idiopathic TN at Stanford University and the Rocky Mountain CyberKnife Center. Patients with atypical pain, multiple sclerosis, or previous radiosurgical treatment or a follow-up duration of less than 6 months were excluded. Patients were evaluated for the level of pain control, response rate, time to pain relief, occurrence of hypesthesia, and time to pain recurrence with respect to the length of the nerve treated and the maximum and the minimum dose to the nerve margin. Thirty-eight patients (92.7%) experienced initial pain relief at a median of 7 days after treatment (range, 24 hours-4 months). Pain control was ranked as excellent in 36 patients (87.8%), moderate in two (4.9%), and three (7.3%) reported no change. Six (15.8%) of the 38 patients with initial relief experienced a recurrence of pain at a median of 6 months (range 2-8 months). Long-term response after a mean follow-up time of 11 months was found in 32 (78%) of 41. Twenty-one patients (51.2%) experienced numbness after treatment. CONCLUSIONS: CyberKnife radiosurgery for TN has high rates of initial pain control and short latency to pain relief compared with those reported for other radiosurgery systems. The doses used for treatment were safe and effective. Higher prescribed doses were not associated with improvement in pain relief or recurrence rate. The hypesthesia rate was related to the length of the trigeminal nerve treated.

Intraoperative three-dimensional fluoroscopy-based computerized tomography guidance for percutaneous kyphoplasty.

OBJECT: Percutaneous kyphoplasty is an established method for the treatment of pathological vertebral compression fractures (VCFs). This procedure is usually performed with the aid of biplanar fluoroscopic image guidance. There are currently no published clinical studies in which the use of three-dimensional (3D) image guidance to facilitate this technique has been evaluated. The purpose of this study was to evaluate the efficacy of isocentric fluoroscopy-based navigation for the kyphoplasty procedure, with special reference to operating time and the amount of radiation exposure. METHODS: A prospective clinical study was performed in which 11 consecutive patients with painful pathological VCFs that did not respond to conservative treatment underwent the kyphoplasty procedure. During this procedure, cannulation of the pedicle and vertebral body was performed with the aid of isocentric 3D fluoroscopy visualization. Total operating time and intraoperative fluoroscopy time for this group was compared with a cohort of nine patients who underwent the procedure prior to the availability of isocentric fluoroscopy (only biplanar fluoroscopy was used). Possible complications such as cement extravasations were evaluated during the procedure and on postoperative computerized tomography scans. The mean duration of surgery for the 3D isocentric fluoroscopic guidance group was 60 minutes (range 36-89 minutes) for one-level and 68.5 minutes (range 65-75 minutes) for two-level cases. Because of a learning curve with the equipment, the operating time for the initial cases was significantly longer than with the later ones. Even with the initial cases included, the mean operating time was shorter compared with the biplanar fluoroscopy-assisted procedures, which averaged 69.2 minutes (range 44-113 minutes) for one-level procedures. This difference was not statistically significant. The mean fluoroscopy exposure time was 41.3 seconds (range 25-62 seconds) in the isocentric fluoroscopy-assisted procedures, with an additional 40 seconds of fluoroscopy time used for the 3D fluoroscopy "spin," compared with 293.2 seconds (range 180-400 seconds) in the biplanar fluoroscopy-assisted procedures. The difference was statistically significant (p = 0.02). All pedicles were accessed without difficulty and no complications were encountered in either group of patients. CONCLUSIONS: The main advantage of isocentric fluoroscopy is the significant reduction in radiation exposure for the patient and surgical staff without an increase in the mean operating time. This technique is a significant advancement over biplanar fluoroscopy in this setting.

Biomechanical comparison of anterior versus posterior lumbar threaded interbody fusion cages.

STUDY DESIGN: Biomechanical flexibility tests were performed in specimens receiving anterior lumbar interbody fixation or posterior lumbar interbody fixation using dual threaded cages. OBJECTIVES: To determine differences in stability between anterior lumbar interbody fixation and posterior lumbar interbody fixation immediately after surgery and after fatigue. SUMMARY OF BACKGROUND DATA: No direct biomechanical comparison of lumbar fixation with threaded anterior lumbar interbody fixation or posterior lumbar interbody fixation cages has been performed previously. METHODS.: Sixteen anterior lumbar interbody fixation specimens and 16 posterior lumbar interbody fixation specimens underwent nondestructive biomechanical testing. Flexibility was assessed during applied flexion, extension, lateral bending, axial rotation, and anteroposterior shear before and after fixation and fatigue. After testing, specimens were dissected, and the quality of fixation was graded. RESULTS: Variability in angular range of motion after fixation was greater than normal interspecimen variability by 89% after anterior lumbar interbody fixation and by 117% after posterior lumbar interbody fixation. During flexion-extension and lateral bending, posterior lumbar interbody fixation allowed a mean of 60% smaller neutral zones than anterior lumbar interbody fixation (P < 0.05, nonpaired Student t test). During axial rotation, anterior lumbar interbody fixation allowed 15% less range of motion than posterior lumbar interbody fixation unless facets were kept intact with posterior lumbar interbody fixation (6 of 16 specimens), in which case anterior lumbar interbody fixation allowed 41% greater range of motion than posterior lumbar interbody fixation. During anteroposterior shear, both anterior lumbar interbody fixation and posterior lumbar interbody fixation restrained range of motion to within 50% of normal. Anterior lumbar interbody fixation loosened, on average, 130% more with fatigue than posterior lumbar interbody fixation during anteroposterior shear. CONCLUSIONS: Both anterior lumbar interbody fixation and posterior lumbar interbody fixation provided inconsistent stability. Therefore, stand-alone anterior lumbar interbody fixation or posterior lumbar interbody fixation may often be ineffective clinically. During all modes of loading except axial rotation, posterior lumbar interbody fixation performed slightly better than anterior lumbar interbody fixation, perhaps due to deeper hole preparation and destruction of anterior stabilizers necessary for anterior lumbar interbody fixation. Avoiding resection of facets during posterior lumbar interbody fixation led to significantly better performance during axial rotation.