✓Metastatic disease to the brain occurs in a significant percentage of patients with cancer and can limit survival and worsen quality of life. Glucocorticoids and whole-brain radiation therapy (WBRT) have been the mainstay of intracranial treatments, while craniotomy for tumor resection has been the standard local therapy. In the last few years however, stereotactic radiosurgery (SRS) has emerged as an alternative form of local therapy. Studies completed over the past decade have helped to define the role of SRS. The authors review the evolution of the techniques used and the indications for SRS use to treat brain metastases. Stereotactic radiosurgery, compared with craniotomy, is a powerful local treatment modality especially useful for small, multiple, and deep metastases, and it is usually combined with WBRT for better regional control.
Michael L. Smith and John Y. K. Lee
John Y. K. Lee and Douglas Kondziolka
Deep brain stimulation (DBS) of the thalamus is used for the treatment of patients with medically refractory essential tremor (ET). The authors evaluated patient outcomes after DBS surgery.
Clinical outcomes were evaluated in 19 patients who had undergone DBS surgery by using the Fahn-Tolosa-Marin clinical tremor rating scale. All adverse outcomes were also systematically recorded during follow-up outpatient visits.
Eighteen DBS systems were implanted. The median follow-up period after surgery was 27 months (range 10–75 months). The preoperative mean Fahn-Tolosa-Marin action tremor score was 3.3 ± 0.5, and the postoperative mean score with the DBS system activated was 0.8 ± 0.4. The mean preoperative writing score was 2.8 ± 0.9, and the postoperative mean writing score with the DBS system activated was 1 ± 0.6. (Wilcoxon rank-sum test, p < 0.005). Fourteen patients were treated with bipolar stimulation, and four eventually required monopolar stimulation. Complications included lead breakage (one patient); temporary erythema of the incision through which the pulse generator had been implanted, which required oral antibiotics (one patient); electrode migration, which required surgery (one patient); and mild hand tingling during stimulation (three patients). Twelve of 18 patients with implanted systems experienced no morbid condition.
Thalamic DBS is safe and effective for medically refractory ET. Stimulator adjustments can frequently occur in some patients, and tremor may worsen despite a readjustment in the system.
David W. Roberts
John Y. K. Lee, John T. Pierce, Sukhmeet K. Sandhu, Dmitriy Petrov and Andrew I. Yang
Endoscopic surgery has revolutionized surgery of the ventral skull base but has not yet been widely adopted for use in the cerebellopontine angle. Given the relatively normal anatomy of the cerebellopontine angle in patients with trigeminal neuralgia (TN), the authors hypothesized that a fully endoscopic microvascular decompression (E-MVD) might provide pain outcomes equivalent to those of microscopic MVD (M-MVD) but with fewer complications.
The authors conducted a single-institution, single-surgeon retrospective study with patients treated in the period of 2006–2013. Before surgery, all patients completed a questionnaire that included a validated multidimensional pain-outcome tool, the Penn Facial Pain Scale (PFPS, formerly known as Brief Pain Inventory–Facial), an 11-point scale that measures pain intensity, interference with general activities of daily living (ADLs), and facial-specific ADLs. Using a standardized script, independent research assistants conducted follow-up telephone interviews.
In total, 167 patients were available for follow-ups (66.5% female; 93 patients underwent M-MVD and 74 underwent E-MVD). Preoperative characteristics (i.e., TN classification, PFPS components, and medication use) were similar for the 2 surgical groups except for 2 variables. Patients in the M-MVD group had slightly higher incidence of V3 pain, and the 2 groups differed in the date of surgery and hence in the length of follow-up (2.4 years for the M-MVD group and 1.3 years for the E-MVD group, p < 0.05). There was a trend toward not finding neurovascular conflict at the time of surgery more frequently in the M-MVD than in the E-MVD group (11% vs 7%, p = 0.052). Internal neurolysis was more often performed in the E-MVD group (26% vs 7%, p = 0.001). The 2 groups did not significantly differ in the length of the MVD procedure (approximately 2 hours). Self-reported headaches at 1 month postoperatively were present in 21% of the patients in the M-MVD group versus 7% in the E-MVD group (p = 0.01). Pain outcomes at the most recent followup were equivalent, with patients reporting a 5- to 6-point (70%–80%) improvement in pain intensity, a 5-point (85%) improvement in pain interference with ADLs, and a 6-point (85%) improvement in interference with facial-specific ADLs. Actuarial freedom from pain recurrence was equivalent in the 2 groups, with 80% pain control at 3 years.
Both the fully endoscopic MVD and the conventional M-MVD appear to provide patients with equivalent pain outcomes. Complication rates were also similar between the groups, with the exception of the rate of headaches, which was significantly lower in the E-MVD group 1 month postoperatively.
John Y. K. Lee, Ajay Niranjan, James McInerney, Douglas Kondziolka, John C. Flickinger and L. Dade Lunsford
Object. To evaluate long-term outcomes of patients who have undergone stereotactic radiosurgery for cavernous sinus meningiomas, the authors retrospectively reviewed their 14-year experience with these cases.
Methods. One hundred seventy-six patients harbored meningiomas centered within the cavernous sinus. Seventeen patients were lost to follow-up review, leaving 159 analyzable patients, in whom 164 procedures were performed. Seventy-six patients (48%) underwent adjuvant radiosurgery after one or more attempts at surgical resection. Eighty-three patients (52%) underwent primary radiosurgery. Two patients (1%) had previously received fractionated external-beam radiation therapy. Four patients (2%) harbored histologically verified atypical or malignant meningiomas. Conformal multiple isocenter gamma knife surgery was performed. The median dose applied to the tumor margin was 13 Gy.
Neurological status improved in 46 patients (29%), remained stable in 99 (62%), and eventually worsened in 14 (9%). Adverse effects of radiation occurred after 11 procedures (6.7%). Tumor volumes decreased in 54 patients (34%), remained stable in 96 (60%), and increased in nine (6%). The actuarial tumor control rate for patients with typical meningiomas was 93.1 ± 3.3% at both 5 and 10 years. For the 83 patients who underwent radiosurgery as their sole treatment, the actuarial tumor control rate at 5 years was 96.9 ± 3%.
Conclusions. Stereotactic radiosurgery provided safe and effective management of cavernous sinus meningiomas. We believe it is the preferred management strategy for tumors of suitable volume (average tumor diameter ≤ 3 cm or volume ≤ 15 cm3).
Leif-Erik Bohman, John Pierce, James H. Stephen, Sukhmeet Sandhu and John Y. K. Lee
Fully endoscopicmicrovascular decompression (E-MVD) of the trigeminal nerve was initially described more than 1 decade ago, but has not yet gained wide acceptance. The authors present the experience of their first 47 consecutive E-MVDs for trigeminal neuralgia (TN).
All surgeries were performed by a single surgeon (J.Y.K.L.) at the Pennsylvania Hospital at the University of Pennsylvania. Patients prospectively completed pain scales before and after surgery by using the Brief Pain Inventory–Facial outcomes tool. All patients were called on the telephone, and the same outcome tool was administered without reference to their preoperative pain status.
Forty-seven patients (17 men) were identified and enrolled. Forty (85%) had Burchiel Type 1 TN. Vascular compression was observed at surgery in 42 patients (89%). No surgery was aborted or converted to microscope. One patient suffered permanent hearing loss, for a permanent neurological morbidity rate of 2%. Overall improvement in pain outcomes was excellent, with a median maximum pain intensity preoperatively of 10 and postoperatively of 0 (p< 0.0001). The mean interference with global function scores were 6.2 preoperatively and reduced to 1.0 at last follow-up (p < 0.0001). The mean interference with facial function was 7.3 preoperatively and reduced to 1.2 at last follow-up (p < 0.0001). The mean follow-up period after surgery was 15 ± 8 months.
In experienced hands, E-MVD offers superb visualization and illumination and is both safe and effective, at least in the short term. Further longer-term study is needed to compare E-MVD to traditional microscopic MVD.
Douglas Kondziolka, Joseph G. Ong, John Y. K. Lee, Robert Y. Moore, John C. Flickinger and L. Dade Lunsford
The purpose of this study was to evaluate the results following Gamma Knife thalamotomy (GKT) for medically refractory essential tremor in a series of patients in whom open surgical techniques were not desirable.
Thirty-one patients underwent GKT for disabling essential tremor after medical therapy had failed. Their mean age was 77 years. Most patients were elderly or had concomitant medical illnesses. A single 4-mm isocenter was used to target a maximum dose of 130 or 140 Gy to the nucleus ventralis intermedius. Items from the Fahn-Tolosa-Marin clinical tremor rating scale were used to grade tremor and handwriting before and after radiosurgery.
The median follow-up was 36 months. In the group of 26 evaluable patients, the mean tremor score (± standard deviation) was 3.7 ± 0.1 preoperatively and 1.7 ± 0.3 after radiosurgery (p < 0.000015). The mean handwriting score was 2.8 ± 0.2 before GKT and 1.7 ± 0.2 afterward (p < 0.0002). After radiosurgery, 18 patients (69%) showed improvement in both action tremor and writing scores, 6 (23%) only in action tremor scores, and 3 (12%) in neither tremor nor writing. Permanent mild right hemiparesis and speech impairment developed in 1 patient 6 months after radiosurgery. Another patient had transient mild right hemiparesis and dysphagia.
Gamma Knife thalamotomy is a safe and effective therapy for medically refractory essential tremor. Its use is especially valuable for patients ineligible for radiofrequency thalamotomy or deep brain stimulation. Patients must be counseled on potential complications, including the low probability of a delayed neurological deficit.
Sukhmeet K. Sandhu, Casey H. Halpern, Venus Vakhshori, Keyvan Mirsaeedi-Farahani, John T. Farrar and John Y. K. Lee
Neurosurgeons are frequently the primary physicians measuring pain relief in patients with trigeminal neuralgia (TN). Unfortunately, the measurement of pain can be complex. The Brief Pain Inventory–Facial (BPI-Facial) is a reliable and validated multidimensional tool that consists of 18 questions. It measures 3 domains of pain: 1) pain intensity (worst and average pain intensity), 2) interference with general activities of daily living (ADL), and 3) face-specific pain interference. The objective of this paper is to determine the patient-reported minimum clinically important difference (MCID) using the BPI-Facial.
The authors conducted a retrospective study of 234 patients with TN seen in a single neurosurgeon's office. Patients completed baseline and 1-month follow-up BPI-Facial questionnaires. The MCID was calculated using an anchor-based approach in which the defined anchor was the 7-point patient global impression of change (PGIC). Two statistical methods were employed: mean change score and optimal cutoff point.
Using the mean change score method, the investigators calculated the MCID for the 3 domains of the BPIFacial: 44% and 30% improvement in pain intensity at its worst and average, respectively, 54% improvement in interference with general ADL, and 63% improvement in interference with facial ADL. Using the optimal cutoff point method, they also calculated the MCID for the 3 domains of the BPI-Facial: 57% and 28% improvement in pain intensity at its worst and average, respectively, 75% improvement in interference with general ADL, and 62% improvement in interference with facial ADL.
The BPI-Facial is a multidimensional pain scale that measures 3 domains of pain. Although 2 statistical methods were used to calculate the MCID, the optimal cutoff point method was the superior one because it used data from the majority of subjects included in this study. A 57% improvement in pain intensity at its worst and a 28% improvement in pain intensity at its average were the MCIDs for patients with facial pain. A greater improvement was needed to achieve the MCID for interference with general and facial ADL. A 75% improvement in interference with general ADL and a 62% improvement in interference with facial ADL were needed to achieve an MCID. While pain intensity is easier to measure, pain's interference with ADL may be more important for patient outcomes when designing or evaluating interventions in the field of TN. The BPI-Facial is a useful instrument to measure changes in multidimensional aspects of pain in patients with TN.
John Y. K. Lee, Sukhmeet Sandhu, Denise Miller, Timothy Solberg, Jay F. Dorsey and Michelle Alonso-Basanta
Gamma Knife radiosurgery (GKRS) utilizes cobalt-60 as its radiation source, and thus dose rate varies as the fixed source decays over its half-life of approximately 5.26 years. This natural decay results in increasing treatment times when delivering the same cumulative dose. It is also possible, however, that the biological effective dose may change based on this dose rate even if the total dose is kept constant. Because patients are generally treated in a uniform manner, radiosurgery for trigeminal neuralgia (TN) represents a clinical model whereby biological efficacy can be tested. The authors hypothesized that higher dose rates would result in earlier and more complete pain relief but only if measured with a sensitive pain assessment tool.
One hundred thirty-three patients were treated with the Gamma Knife Model 4C unit at a single center by a single neurosurgeon during a single cobalt life cycle from January 2006 to May 2012. All patients were treated with 80 Gy with a single 4-mm isocenter without blocking. Using an output factor of 0.87, dose rates ranged from 1.28 to 2.95 Gy/min. The Brief Pain Inventory (BPI)-Facial was administered before the procedure and at the first follow-up office visit 1 month from the procedure (mean 1.3 months). Phone calls were made to evaluate patients after their procedures as part of a retrospective study. Univariate and multivariate linear regression was performed on several independent variables, including sex, age in deciles, diagnosis, follow-up duration, prior surgery, and dose rate.
In the short-term analysis (mean 1.3 months), patients’ self-reported pain intensity at its worst was significantly correlated with dose rate on multivariate analysis (p = 0.028). Similarly, patients’ self-reported interference with activities of daily living was closely correlated with dose rate on multivariate analysis (p = 0.067). A 1 Gy/min decrease in dose rate resulted in a 17% decrease in pain intensity at its worst and a 22% decrease in pain interference with activities of daily living. In longer-term follow-up (mean 1.9 years), GKRS with higher dose rates (> 2.0 Gy/min; p = 0.007) and older age in deciles (p = 0.012) were associated with a lower likelihood of recurrence of pain.
Prior studies investigating the role of dose rate in Gamma Knife radiosurgical ablation for TN have not used validated outcome tools to measure pain preoperatively. Consequently, differences in pain outcomes have been difficult to measure. By administering pain scales both preoperatively as well as postoperatively, the authors have identified statistically significant differences in pain intensity and pain interference with activities of daily living when comparing higher versus lower dose rates. Radiosurgery with a higher dose rate results in more pain relief at the early follow-up evaluation, and it may result in a lower recurrence rate at later follow-up.