bluuebunny/crossref_metadata_2025 huggingface dataset:
Being Inside and Outside Social Relations
Authors: Rapport Nigel
Published: November 2018

It is a special responsibility to incur individual readings of one’s work from colleagues. I hope the following line of thought does them justice.

Nay Rather, an essay by Anne Carson (a translator and poet as well as a classical scholar), begins with an account of the trial of Joan of Arc. Caught in battle against the English and their Burgundian allies on 23 May 1430, a year after she had assisted a French army in lifting the English siege of Orleans, Joan of Arc was put on trial for heresy. The trial lasted from January to May 1431, and Joan was burnt at the stake on 30 May, aged nineteen. In recounting this history, Carson explains that she is particularly interested in the way in which, as she puts it, Joan was ‘distant’ from her own words. Carson (2014: 8) elaborates. Joan of Arc’s guidance, military and moral came from a source that she called ‘voices’. She began to hear them at the age of twelve, and they commanded her style of dress, her beliefs and the revolutionary politics of her action. At her trial, her English ecclesiastical prosecutors wanted to know her voices, for Joan to name and describe them in ways in which they might understand: in terms of recognised religious imagery and emotions, and in a conventional narrative that might then be subjected to mechanisms of theological proof.
Gamma Knife surgery for large cerebral arteriovenous malformations
Authors: Kim Hae Yu , Chang Won Seok , Kim Dong Joon , Lee Jae Whan , Chang Jin Woo , Kim Dong Ik , Huh Seung Kon , Park Yong Gou , Chang Jong Hee
Published: November 2018

Object

Treatment of arteriovenous malformations (AVMs) is problematic due to many factors, including lesion size, lesion location, unacceptable complications, and negative outcomes. To overcome the limitation imposed by a large nidus volume, neurosurgeons have used Gamma Knife surgery (GKS) in a variety of ways, including combined with other treatment modalities, as volume-staged radiosurgery, and as repeat radiosurgery. We performed repeat radiosurgeries in patients who harbored large AVMs (> 30 cm3) and analyzed the AVM obliteration rates and complications.

Methods

The authors reviewed the cases of 44 patients at a single institution who underwent GKS between 1992 and 2007 for treatment of an AVM whose nidus was 30 cm3 or larger. The mean age of the patients was 27 years (range 4.5–62.3 years), and the median duration of follow-up was 109.4 months (range 27–202 months). The mean AVM nidus volume was 48.8 cm3 (range 30.3–109.5 cm3), and the mean radiation dose delivered to the margin of the nidus was 13.9 Gy (range 8.4–17.5 Gy). The authors determined complete AVM nidus obliteration based on findings on both MR images and digital subtraction angiograms. When they did not detect complete obliteration after GKS, they performed 1 or more additional GKSs separated by a minimum interval of 3 years.

Results

The overall obliteration rate following repeat GKS was 34.1%, and the estimated obliteration rate at 120 months was 41.8%. Three patients (6.8%) experienced hemorrhages after GKS, and 2 patients (4.5%) developed cysts. One patient (2.3%) experienced a newly developed seizure following GKS, and another patient (2.3%) was found to have radiation necrosis.

Conclusions

Even though complete obliteration of the large AVMs after repeat GKS took a long time, the complication rate was quite acceptable. In addition, the estimated obliteration rate at long-term follow-up was respectable. Repeat GKS should be considered as a primary treatment option for symptomatic large AVMs to overcome the limitation imposed on successful obliteration by the large volume of the nidus.
Does the Gamma Knife dose rate affect outcomes in radiosurgery for trigeminal neuralgia?
Authors: Arai Yoshio , Kano Hideyuki , Lunsford L. Dade , Novotny Josef , Niranjan Ajay , Flickinger John C. , Kondziolka Douglas
Published: November 2018

Object

The object of this study was to determine whether the radiation dose rate affects clinical outcomes in patients who undergo stereotactic Gamma Knife surgery (GKS) to manage typical trigeminal neuralgia (TN).

Methods

The authors retrospectively studied pain relief in 165 patients with medically intractable TN, who underwent 80-Gy GKS using a single 4-mm collimator between 1994 and 2005. No patient had received prior radiation treatment. The measured relative helmet output factor of the Gamma Knife was 0.8 throughout this interval, and the dose rate varied from 1.21 Gy/minute to 3.74 Gy/minute (median 2.06 Gy/minute). Irradiation time varied from 26.73 to 95.11 minutes. The authors divided patients into a low-dose-rate (LDR) group, in which the dose rate varied from 1.21 to 2.05 Gy/minute, and a high-dose-rate (HDR) group, in which the dose rate varied from 2.06 to 3.74 Gy/minute. Post-GKS, the patients' pain control was determined using the Barrow Neurological Institute (BNI) pain scale.

There was no statistically significant difference between groups with respect to history of prior microvascular decompression (p = 0.410) or peripheral neuroablative procedures (p = 0.583). The length of symptoms in patients varied from 3 to 414 months with a median of 84 months (p = 0.698). Median follow-up was 26 months with a maximum of 139 months.

Results

Initial pain relief was obtained in 71% of patients in the LDR group and 78% in the HDR group (p = 0.547). Patients who initially obtained improved pain relief (BNI Scores I–IIIa) after GKS maintained pain control for median durations of 52 months (LDR group) and 54 months (HDR group) (p = 0.403). New or increased facial sensory dysfunction was found in 14.5% of patients in the LDR group and in 19.3% of patients in the HDR group (p = 0.479).

Conclusions

The authors found that the GKS dose rate did not affect pain control or morbidity within the range of 1.21–3.74 Gy/minute. Cobalt 60 source decay did not affect outcomes of GKS for TN pain management, even for dose rates approximating a 2-half-life decay of the isotope.
Gamma Knife surgery for hypothalamic hamartomas and epilepsy: patient selection and outcomes
Authors: Abla Adib A. , Shetter Andrew G. , Chang Steve W. , Wait Scott D. , Brachman David G. , Ng Yu-Tze , Rekate Harold L. , Kerrigan John F.
Published: November 2018

Object

The authors present outcomes obtained in patients who underwent Gamma Knife surgery (GKS) at 1 institution as part of a multimodal treatment of refractory epilepsy caused by hypothalamic hamartomas (HHs).

Methods

Between 2003 and 2010, 19 patients with HH underwent GKS. Eight patients had follow-up for less than 1 year, and 1 patient was lost to follow-up. The 10 remaining patients (mean age 15.1 years, range 5.7–29.3 years) had a mean follow-up of 43 months (range 18–81 months) and are the focus of this report. Five patients had undergone a total of 6 prior surgeries: 1 transcallosal resection of the HH, 2 endoscopic transventricular resections of the HH, 2 temporal lobectomies, and 1 arachnoid cyst evacuation. In an institutional review board–approved study, postoperative complications and long-term outcome measures were monitored prospectively with the use of a proprietary database. Seven patients harbored Delalande Type II lesions; the remainder harbored Type III or IV lesions. Seizure frequency ranged from 1–2 monthly to as many as 100 gelastic seizures daily. The mean lesion volume was 695 mm3 (range 169–3000 mm3, median 265 mm3). The mean/median dose directed to the 50% isodose line was 18 Gy (range 16–20 Gy). The mean maximum point dose to the optic chiasm was 7.5 Gy (range 5–10 Gy). Three patients underwent additional resection 14.5, 21, and 32 months after GKS.

Results

Of the 10 patients included in this study, 6 are seizure free (2 after they underwent additional surgery), 1 has a 50%–90% reduction in seizure frequency, 2 have a 50% reduction in seizure frequency, and 1 has observed no change in seizure frequency. Overall quality of life, based on data obtained from follow-up telephone conversations and/or surveys, improved in 9 patients and was due to improvements in seizure control (9 patients), short-term memory loss (3 patients), and behavioral symptoms (5 patients); in 1 patient, quality of life remains minimally affected. Incidences of morbidity were all temporary and included poikilothermia (1 patient), increased depression (1 patient), weight gain/increased appetite (2 patients), and anxiety (1 patient) after GKS.

Conclusions

Of the approximately 150 patients at Barrow Neurological Institute who have undergone treatment for HH, the authors have reserved GKS for treatment of small HHs located distal from radiosensitive structures in patients with high cognitive function and a stable clinical picture, which allows time for the effects of radiosurgery to occur without further deterioration. The lack of significant morbidity and the clinical outcomes achieved in this study demonstrated a low risk of GKS for HH with results comparable to those of previous series.
Gamma Knife surgery for hypothalamic hamartomas causing refractory epilepsy: preliminary results from a prospective observational study
Authors: Mathieu David , Deacon Charles , Pinard Catherine-Andrée , Kenny Brendan , Duval Julie
Published: November 2018

Object

Hypothalamic hamartomas (HHs) are congenital lesions typically presenting with medically refractory epilepsy. Open or endoscopic surgical procedures to remove or disconnect the hamartoma have been reported to be effective but are associated with significant morbidity. The authors of studies on Gamma Knife surgery for HHs have reported an encouraging rate of epilepsy resolution with minimal side effects. At the Centre Hospitalier Universitaire de Sherbrooke, the authors have undertaken a prospective observational study of the outcomes of patients who underwent radiosurgery for HHs.

Methods

Patients were included in the study if they had an HH, refractory epilepsy, and no other suspected seizure focus. After radiosurgery, seizure status was assessed every 3 months and reported using the Engel Classification. Quality of life evaluation was performed annually using a standardized questionnaire, and neuropsychological evaluation was performed after 2 years.

Results

Nine patients were included in the study. They ranged in age from 12 to 57 years. Epilepsy began in infancy in all cases and was refractory to standard antiepileptic drugs. The patients received an average of 2 antiepileptic drugs before undergoing radiosurgery. Using the Régis Classification, 6 patients had smaller hamartomas (Grade I–III) and underwent treatment of the entire lesion, using a margin dose of 14–20 Gy. Treatment volume ranged from 0.3 to 1.0 ml. Three patients had larger lesions (Grade IV–VI) for which a radiosurgical disconnection was attempted, targeting the area of attachment to the hypothalamus. For those patients, the margin dose was 15 or 16 Gy, with treatment volume ranging from 0.8 to 1.8 ml. In all patients, the radiation dose received by the optic pathways was kept below 10 Gy. Disconnection led to no improvement in epilepsy (Engel Class IV). Four patients in whom the entire lesion was treated are now seizure free (Engel Class I), with another having only rare seizures (Engel Class II). Quality of life and verbal memory were improved in those patients with more than 3 years of follow-up. No adverse event occurred after radiosurgery.

Conclusions

Radiosurgery safely and effectively controlled the epileptic disorder in patients with HHs when the entire lesion could be targeted. Radiosurgical disconnection is ineffective and cannot be recommended.
Prospective evaluation of a dedicated spine radiosurgery program using the Elekta Synergy S system
Authors: Gerszten Peter C. , Novotny Josef , Quader Mubina , Dewald Valerie C. , Flickinger John C.
Published: November 2018

Object

Cone beam CT (CBCT) image guidance has recently been adopted for the delivery of spine radiosurgery. In 2007, the authors' institution began a dedicated spine radiosurgery program using the Elekta Synergy S system, which incorporates CBCT technology. In this study, the authors prospectively evaluated the Synergy S platform as a dedicated spine radiosurgery delivery system, including an evaluation of the accuracy of patient positioning using this technology, as part of a quality assurance program.

Methods

One hundred sixty-six spine and paraspinal lesions were treated using the Elekta Synergy S 6-MV LINAC with a beam modulator and CBCT image guidance combined with a HexaPOD couch that allows correction of patient positioning in 3 translational and 3 rotational directions. Stratifying the lesion by location, there were 28 cervical, 69 thoracic, 48 lumbar, and 21 sacral lesions. The most common histological types for the metastatic lesions (136 cases total) were breast, lung, sarcomas, and renal cells. The most common benign tumors (30 cases total) included 10 schwannomas, 5 neurofibromas, and 5 meningiomas. Twenty-eight lesions (17%) were intradural. To measure intratreatment patient movement, 3 quality assurance CBCTs were performed and recorded at separate times: immediately before treatment started; at the first third of the procedure; and at the second third of the procedure. The positioning data and fused images of the planning CT and CBCT were analyzed to determine intrafraction patient movements. From each of 3 quality assurance CBCT images, 3 translational and 3 rotational coordinates were obtained.

Results

The prescribed dose to the gross tumor volume, delivered in a single fraction, ranged from 12 to 20 Gy (mean 16 Gy) in this cohort. This dose was delivered by between 7 and 14 coplanar intensity-modulated radiation therapy beams (mean 9 beams). The gross tumor volumes ranged from 1.2 to 491.7 cm3 (mean 39.2 cm3). Mean treatment time including setup was 64 minutes. At the first third of the treatment, the magnitude of the 3D translational vector (X, Y, Z) was 1.1 ± 0.7 mm. Similarly, the 3D translational vector at the second third of the treatment was 1.0 ± 0.6 mm. The means ± SDs of the rotational angles were 0.2° ± 0.4°, 0.4° ± 0.5°, and 0.3° ± 0.5° along yaw, roll, and pitch, respectively, at the first third of the treatment, and 0.2° ± 0.3°, 0.4° ± 0.5°, and 0.4° ± 0.5°, respectively, at the second third of the treatment.

Conclusions

Single-fraction spine radiosurgery performed using the Synergy S platform and incorporating CBCT image guidance was determined to be feasible, accurate, and safe. This technique provides an overall translational position accuracy of < 2.0 mm.
Tumor shrinkage of vestibular schwannomas after Gamma Knife surgery: results after more than 5 years of follow-up
Authors: Nagano Osamu , Serizawa Toru , Higuchi Yoshinori , Matsuda Shinji , Sato Makoto R.T. , Yamakami Iwao , Okiyama Koichi , Ono Junichi , Saeki Naokatsu
Published: November 2018

Object

The authors prospectively analyzed volume changes in vestibular schwannomas (VSs) after Gamma Knife surgery (GKS).

Methods

Among 104 VSs treated by GKS at the Chiba Cardiovascular Center between 1998 and 2004, 87 consecutively treated unilateral VSs observed on follow-up MR imaging for at least 5 years were analyzed. These lesions were harbored by 31 men and 56 women, with a mean age of 58.6 years (range 29–80 years). The Gd-enhanced volume of each lesion was measured serially every 3 months during the 1st year and every 6 months thereafter using GammaPlan or SurgiPlan. The frequency and degree of volume shrinkage were documented and possible prognostic factors were analyzed.

Results

The mean tumor volume at GKS was 2.5 cm3 (range 0.1–13.2 cm3). The lesions were irradiated by directing a mean dose of 12.0 Gy (range 10.5–13.0 Gy) to the tumor margin, which was located at the mean 52.2% isodose line (range 50%–67% isodose line). The mean follow-up period was 7.5 years (range 5.0–11.1 years). Peak tumor volume expansion was most frequently observed at 8.6 months after GKS and averaged 58% (range 0%–613%). Five years after GKS, the mean reduction in tumor volume was 31%, and 9 tumors still remained larger than their initial volumes. Tumors that homogeneously enhanced on MR images displayed less shrinkage than other tumors.

Conclusions

Most VSs exhibit shrinkage 5 years after GKS. The mean volume reduction in this series was 31%. These results indicate that careful serial follow-up is necessary for patients who harbor tumors that display homogeneous enhancement on MR images and patients whose tumors continue to expand in size after GKS.
Gamma Knife surgery for low-flow cavernous sinus dural arteriovenous fistulas
Authors: Jung Hyun Ho , Chang Jong Hee , Whang Kum , Pyen Jin Soo , Chang Jin Woo , Park Yong Gou
Published: November 2018

Object

The purpose of this study was to assess the efficacy of Gamma Knife surgery (GKS) for treating cavernous sinus dural arteriovenous fistulas (CSDAVFs).

Methods

Of the 4123 GKSs performed between May 1992 and March 2009, 890 procedures were undertaken to treat vascular lesions. In 24 cases, the vascular lesion that was treated was a dural arteriovenous fistula, and in 6 of these cases, the lesion involved the cavernous sinus. One of these 6 cases was lost to follow-up, leaving the other 5 cases (4 women and 1 man) to comprise the subjects of this study. All 5 patients had more than 1 ocular symptom, such as ptosis, chemosis, proptosis, and extraocular movement palsy. In all patients, CSDAVF was confirmed by conventional angiography. Three patients were treated by GKS alone and 2 patients were treated by GKS combined with transarterial embolization. The median follow-up period after GKS in these 5 cases was 30 months (range 9–59 months).

Results

All patients experienced clinical improvement, and their improvement in ocular symptoms was noticed at a mean of 17.6 weeks after GKS (range 4–24 weeks). Two patients received embolization prior to GKS but did not display improvement in ocular symptoms. An average of 20 weeks (range 12–24 weeks) was needed for complete improvement in clinical symptoms. There were no treatment-related complications during the follow-up period.

Conclusions

Gamma Knife surgery should be considered as a primary, combined, or additional treatment option for CSDAVF in selected cases, such as when the lesion is a low-flow shunt without cortical venous drainage. For those selected cases, GKS alone may suffice as the primary treatment method when combined with close monitoring of ocular symptoms and intraocular pressure.
Intracapsular decompression or radical resection followed by Gamma Knife surgery for patients harboring a large vestibular schwannoma
Authors: Pan Hung-Chuan , Sheehan Jason , Sheu Meei-Ling , Chiu Wen-Ta , Yang Dar-Yu
Published: November 2018

Object

Microsurgery is the primary treatment used for patients harboring a large vestibular schwannoma (VS). However, its outcome may lead to hearing impairment and facial nerve dysfunction particularly when resection is extended outside the tumor capsule. When surgery for a large VS consists of intracapsular resection and decompression, better preservation of facial and hearing function are obtained. In this study, the authors compared outcomes of intracapsular decompression followed by Gamma Knife surgery (GKS) with outcomes of standard microsurgery followed by radiosurgery.

Methods

Between August 2003 and October 2008, 35 patients harboring large VSs (> 3 cm in diameter) were enrolled in this study. Eighteen patients underwent intracapsular decompression followed by GKS (Group I), and 17 patients underwent radical extracapsular resection followed by GKS (Group II). In all cases GKS was performed with a margin dose of 12 Gy. All patients were followed up for at least 3 years. All patients also underwent periodic audiography, electroneuronography (ENoG), MR imaging, and testing with the SF-36 form. The Student t-test and repeated ANOVA were used for statistical analysis.

Results

The mean ages of the patients (± SEM) in Groups I and II were 50 ± 3.0 and 49 ± 2.3 years, respectively. The female/male ratios were 8:10 in Group I and 7:10 in Group II. All patients had excellent facial function as measured according to the House-Brackmann Facial Grading System (Grade I or II) preoperatively. After the operation, 16 patients (89%) in Group I retained excellent facial function, whereas only 6 patients (35%) in Group II had excellent facial function (p < 0.01). In Group I, 11 patients had serviceable hearing, and all 11 (100%) retained hearing function after the operation. In Group II, 11 patients had serviceable hearing, but none retained hearing function postoperatively (p < 0.001). In Group I, the mean tumor volume (± SEM) was 17.5 ± 1.1 cm3, and the postoperative volume was 9.35 ± 1.02 cm3. In Group II, the mean tumor volume was 16.4 ± 0.95 cm3, whereas the postoperative volume was 1.1 ± 0.14 cm3 (p < 0.001). After GKS, the tumor volume was reduced to 5.12 ± 1.1 cm3 and 0.9 ± 0.1 cm3 in Groups I and II, respectively. No patients experienced adverse effects after GKS. The mean return-to-work times were 2.4 ± 0.16 and 33.4 ± 4.3 weeks in Groups I and II, respectively (p < 0.001). According to the results obtained using the 36-Item Short Form Health Survey (SF-36), patients in Group I enjoyed more significant improvements in quality of life than patients in Group II (p < 0.001).

Conclusions

Intracapsular decompression followed by GKS afforded a better neurological outcome and quality of life than radical extracapsular resection followed by GKS. Further application of this approach in patients harboring large VSs seems warranted.
Reliability of contour-based volume calculation for radiosurgery
Authors: Ma Lijun , Sahgal Arjun , Nie Ke , Hwang Andrew , Karotki Aliaksandr , Wang Brian , Shrieve Dennis C. , Sneed Penny K. , McDermott Michael , Larson David A.
Published: November 2018

Object

Determining accurate target volume is critical for both prescribing and evaluating stereotactic radiosurgery (SRS) treatments. The aim of this study was to determine the reliability of contour-based volume calculations made by current major SRS platforms.

Methods

Spheres ranging in diameter from 6.4 to 38.2 mm were scanned and then delineated on imaging studies. Contour data sets were subsequently exported to 6 SRS treatment-planning platforms for volume calculations and comparisons. This procedure was repeated for the case of a patient with 12 metastatic lesions distributed throughout the brain. Both the phantom and patient datasets were exported to a stand-alone workstation for an independent volume-calculation analysis using a series of 10 algorithms that included approaches such as slice stacking, surface meshing, point-cloud filling, and so forth.

Results

Contour data–rendered volumes exhibited large variations across the current SRS platforms investigated for both the phantom (−3.6% to 22%) and patient case (1.0%–10.2%). The majority of the clinical SRS systems and algorithms overestimated the volumes of the spheres, compared with their known physical volumes. An independent algorithm analysis found a similar trend in variability, and large variations were typically associated with small objects whose volumes were < 0.4 cm3 and with those objects located near the end-slice of the scan limits.

Conclusions

Significant variations in volume calculation were observed based on data obtained from the SRS systems that were investigated. This observation highlights the need for strict quality assurance and benchmarking efforts when commissioning SRS systems for clinical use and, moreover, when conducting multiinstitutional cross-SRS platform clinical studies.
Gamma Knife surgery for brainstem metastases
Authors: Li Yanhe , Xu Desheng , Zhang Zhiyuan , Zhang Yipei , Liu Dong , Liu Xiaomin , Wang Guokai , Lin Yiguang
Published: November 2018

Object

The goal of this study was to assess neuroimaging and clinical outcomes in patients harboring brainstem metastases that were treated with the Leksell Gamma Knife.

Methods

Twenty-eight patients with brainstem metastases (32 lesions: 8 midbrain, 21 pontine, and 3 medullary) were consecutively treated with GKS. The primary cancer diagnoses in this group included 22 cases of lung cancer, 5 cases of breast cancer, and 1 case of rectal cancer. The median age of the patients was 61 years (range 45–83 years). The median treated lesion volume was 0.78 cm3 (range 0.03–5.6 cm3), and the median GKS margin dose was 16 Gy (range 12–20 Gy). Overall survival in these patients was calculated using the Kaplan-Meier method.

Results

The median survival time was 9 months after GKS (range 2–32 months). Survival was 39.3% at 1 year and 10.7% at 2 years. The tumor control rate in the series was 90.6% (29 of 32 lesions). Development of peritumoral edema occurred in 1 patient after GKS; 4 months after GKS, the edema disappeared.

Conclusions

Gamma Knife surgery using a median margin dose of 16 Gy is a safe and effective local therapy for patients with brainstem metastases.
Multisession Gamma Knife surgery for benign orbital tumors
Authors: Jo Kyung-Il , Im Yong Seok , Kong Doo-Sik , Seol Ho Jun , Nam Do-Hyun , Kim Yoon-Duck , Lee Jung-Il
Published: November 2018

Object

The goal of this study was to investigate the safety and efficacy of multisession Gamma Knife surgery (GKS) in the treatment of benign orbital tumors.

Methods

Twenty-three patients who retained their vision despite having tumors touching their optic nerve were treated with multisession (4-fraction) GKS. The median tumor volume was 2800 mm3 (range 211–10,800 mm3), and the median cumulative margin dose was 20 Gy (range 18–22 Gy).

Results

The median clinical follow-up duration in these patients was 38 months (range 9–74 months). No patient experienced tumor progression in this study. In particular, a higher degree of tumor shrinkage was found in the 7 patients with cavernous hemangiomas than in patients with other types of lesions (p < 0.05). Of the 23 patients whose preoperative vision was preserved, 11 showed improvement in visual acuity and/or visual field and 12 showed stable visual acuity. No GKS-related adverse events were noted during or after treatment.

Conclusions

Multisession radiosurgery using the Gamma Knife may be a good strategy for tumors in direct contact with the optic nerve. A cumulative margin dose of up to 22 Gy delivered in 4 sessions is safe for preservation of visual function with a high probability of tumor control.
Radiosurgery target location and individual anatomical variation in trigeminal nerves
Authors: Hung Yi-Chieh , Lee Cheng-Chia , Liu Kang-Du , Chung Wen-Yuh , Pan David Hung-Chi , Yang Huai-Che
Published: November 2018

Object

The authors evaluated individual anatomical variations in the trigeminal nerves of patients with medically intractable trigeminal neuralgia and clarified the relationships among the variations, radiosurgical target locations, and the clinical outcomes after high-dose Gamma Knife surgery (GKS).

Methods

From 2006 through 2011, the authors conducted a retrospective review of 106 cases of primary or secondary trigeminal neuralgia consecutively treated with GKS targeting the dorsal root entry zone (DREZ) for which a maximal dose of 90 Gy and a 20% isodose line to the brainstem were used. A questionnaire was used to evaluate patients' pre- and post-GKS clinical conditions. To evaluate individual anatomical variations among trigeminal nerves, the authors used 3 parameters: the length of the trigeminal nerve in the cistern (nerve length), the length of the target between the radiation shot and the brainstem (targeting length), and the ratio between nerve length and targeting length (targeting ratio).

Results

The median length of the trigeminal nerves in the 106 patients was 9.6 mm (range 6.04−20.74 mm), the median targeting length was 3.8 mm (range 1.81−10.84 mm), and the median targeting ratio was 38% (range 13%− 80%). No statistically significant differences in pain relief and pain recurrence were detected among patients with these various nerve characteristics. However, radiation-induced facial hypesthesia correlated with nerve length and targeting ratio (p < 0.05) but not with absolute distance from the brainstem (targeting length).

Conclusions

In trigeminal neuralgia patients who received DREZ-targeted GKS, the rate of pain relief did not differ according to anatomical nerve variations. However, the frequency of facial hypesthesia was higher among patients in whom the nerve was longer (> 11 mm) or the targeting ratio was lower (< 36%). Adjusting the target according to the targeting ratio, especially for patients with longer nerves, can reduce facial hypesthesia and enable maintenance of effective pain control.
Gamma Knife surgery for facial nerve schwannomas
Authors: Moon Ju Hyung , Chang Won Seok , Jung Hyun Ho , Lee Kyu Sung , Park Yong Gou , Chang Jong Hee
Published: November 2018

Object

The aim of this study was to evaluate the tumor control rate and functional outcomes after Gamma Knife surgery (GKS) among patients with a facial nerve schwannoma.

Methods

The authors reviewed the radiological data and clinical records for 14 patients who had consecutively undergone GKS for a facial nerve schwannoma. Before GKS, 12 patients had facial palsy, 7 patients had hearing disturbance, and 5 patients had undergone partial or subtotal tumor resection. The mean and median tumor volumes were 3707 mm3 and 3000 mm3, respectively (range 117–10,100 mm3). The mean tumor margin dose was 13.2 Gy (range 12–15 Gy), and the mean maximum tumor dose was 26.4 Gy (range 24–30 Gy). The mean follow-up period was 80.7 months (range 2–170 months).

Results

Control of tumor growth was achieved in all 12 (100%) patients who were followed up for longer than 2 years. After GKS, facial nerve function improved in 2 patients, remained unchanged in 9 patients, and worsened in 3 patients. All patients who had had serviceable hearing at the preliminary examination maintained their hearing at a useful level after GKS. Other than mild tinnitus reported by 3 patients, no other major complications developed.

Conclusions

GKS for facial nerve schwannomas resulted in excellent tumor control rates and functional outcomes. GKS might be a good primary treatment option for patients with a small- to medium-sized facial nerve schwannoma when facial nerve function and hearing are relatively preserved.
Cervical mismatch: the normative value of T1 slope minus cervical lordosis and its ability to predict ideal cervical lordosis
Authors: Staub Blake N. , Lafage Renaud , Kim Han Jo , Shaffrey Christopher I. , Mundis Gregory M. , Hostin Richard , Burton Douglas , Lenke Lawrence , Gupta Munish C. , Ames Christopher , Klineberg Eric , Bess Shay , Schwab Frank , Lafage Virginie , _ _
Published: November 2018

OBJECTIVE

Numerous studies have attempted to delineate the normative value for T1S−CL (T1 slope minus cervical lordosis) as a marker for both cervical deformity and a goal for correction similar to how PI-LL (pelvic incidence–lumbar lordosis) mismatch informs decision making in thoracolumbar adult spinal deformity (ASD). The goal of this study was to define the relationship between T1 slope (T1S) and cervical lordosis (CL).

METHODS

This is a retrospective review of a prospective database. Surgical ASD cases were initially analyzed. Analysis across the sagittal parameters was performed. Linear regression analysis based on T1S was used to provide a clinically applicable equation to predict CL. Findings were validated using the postoperative alignment of the ASD patients. Further validation was then performed using a second, normative database. The range of normal alignment associated with horizontal gaze was derived from a multilinear regression on data from asymptomatic patients.

RESULTS

A total of 103 patients (mean age 54.7 years) were included. Analysis revealed a strong correlation between T1S and C0–7 lordosis (r = 0.886), C2–7 lordosis (r = 0.815), and C0–2 lordosis (r = 0.732). There was no significant correlation between T1S and T1S−CL. Linear regression analysis revealed that T1S−CL assumed a constant value of 16.5° (R2 = 0.664, standard error 2°). These findings were validated on the postoperative imaging (mean absolute error [MAE] 5.9°). The equation was then applied to the normative database (MAE 6.7° controlling for McGregor slope [MGS] between −5° and 15°). A multilinear regression between C2–7, T1S, and MGS demonstrated a range of T1S−CL between 14.5° and 26.5° was necessary to maintain horizontal gaze.

CONCLUSIONS

Normative CL can be predicted via the formula CL = T1S − 16.5° ± 2°. This implies a threshold of deformity and aids in providing a goal for surgical correction. Just as pelvic incidence (PI) can be used to determine the ideal LL, T1S can be used to predict ideal CL. This formula also implies that a kyphotic cervical alignment is to be expected for individuals with a T1S < 16.5°.
Complications of spinal osteotomy for thoracolumbar kyphosis secondary to ankylosing spondylitis in 342 patients: incidence and risk factors
Authors: Qian Bang-ping , Huang Ji-chen , Qiu Yong , Wang Bin , Yu Yang , Zhu Ze-zhang , Mao Sai-hu , Jiang Jun
Published: November 2018

OBJECTIVE

To describe the incidence of complications in spinal osteotomy for thoracolumbar kyphosis caused by ankylosing spondylitis (AS) and to investigate the risk factors for these complications.

METHODS

From April 2000 to July 2017, 342 consecutive AS patients with a mean age (± SD) of 35.4 ± 9.8 years (range 17–71 years) undergoing spinal osteotomy were enrolled. Patients with complications within the 1st postoperative year were identified. Demographic, radiological, and surgical data were compared between patients with and without complications. The complications were classified into intraoperative and postoperative complications.

RESULTS

A total of 310 consecutive pedicle subtraction osteotomy (PSO) and 37 multiple Smith-Petersen osteotomy (SPO) procedures were performed in 342 patients. Overall, 47 complications were identified in 47 patients (13.7%), including 31 intraoperative complications and 16 postoperative complications. Patients with complications were older than those without (p = 0.006). A significant difference was observed in preoperative global kyphosis (GK), lumbar lordosis (LL), sagittal vertical axis (SVA), and the correction of these radiographic parameters between patients with and without complications (p < 0.05). Two-level PSO (p = 0.022) and an increased number of instrumented vertebrae (p = 0.019) were significantly associated with an increased risk of complications.

CONCLUSIONS

The overall incidence of complications was 13.7%. Age; preoperative GK, LL, and SVA; the correction of GK, LL, and SVA; 2-level PSO; and number of instrumented vertebrae were risk factors. Therefore, the potential risk of extensive surgeries with large correction and long fusion in older AS patients with severe GK should be seriously considered in surgical decision-making.
Current treatment strategy for newly diagnosed chordoma of the mobile spine and sacrum: results of an international survey
Authors: Dea Nicolas , Fisher Charles G. , Reynolds Jeremy J. , Schwab Joseph H. , Rhines Laurence D. , Gokaslan Ziya L. , Bettegowda Chetan , Sahgal Arjun , Lazáry Áron , Luzzati Alessandro , Boriani Stefano , Gasbarrini Alessandro , Laufer Ilya , Charest-Morin Raphaële , Wei Feng , Teixeira William , Germscheid Niccole M. , Hornicek Francis J. , DeLaney Thomas F. , Shin John H. , _ _
Published: November 2018

OBJECTIVE

The purpose of this study was to investigate the spectrum of current treatment protocols for managing newly diagnosed chordoma of the mobile spine and sacrum.

METHODS

A survey on the treatment of spinal chordoma was distributed electronically to members of the AOSpine Knowledge Forum Tumor, including neurosurgeons, orthopedic surgeons, and radiation oncologists from North America, South America, Europe, Asia, and Australia. Survey participants were pre-identified clinicians from centers with expertise in the treatment of spinal tumors. The suvey responses were analyzed using descriptive statistics.

RESULTS

Thirty-nine of 43 (91%) participants completed the survey. Most (80%) indicated that they favor en bloc resection without preoperative neoadjuvant radiation therapy (RT) when en bloc resection is feasible with acceptable morbidity. The main area of disagreement was with the role of postoperative RT, where 41% preferred giving RT only if positive margins were achieved and 38% preferred giving RT irrespective of margin status. When en bloc resection would result in significant morbidity, 33% preferred planned intralesional resection followed by RT, and 33% preferred giving neoadjuvant RT prior to surgery. In total, 8 treatment protocols were identified: 3 in which en bloc resection is feasible with acceptable morbidity and 5 in which en bloc resection would result in significant morbidity.

CONCLUSIONS

The results confirm that there is treatment variability across centers worldwide for managing newly diagnosed chordoma of the mobile spine and sacrum. This information will be used to design an international prospective cohort study to determine the most appropriate treatment strategy for patients with spinal chordoma.
The effect of C2–3 disc angle on postoperative adverse events in cervical spondylotic myelopathy
Authors: Lee Bryan S. , Walsh Kevin M. , Lubelski Daniel , Knusel Konrad D. , Steinmetz Michael P. , Mroz Thomas E. , Schlenk Richard P. , Kalfas Iain H. , Benzel Edward C.
Published: November 2018

OBJECTIVE

Complete radiographic and clinical evaluations are essential in the surgical treatment of cervical spondylotic myelopathy (CSM). Prior studies have correlated cervical sagittal imbalance and kyphosis with disability and worse health-related quality of life. However, little is known about C2–3 disc angle and its correlation with postoperative outcomes. The present study is the first to consider C2–3 disc angle as an additional radiographic predictor of postoperative adverse events.

METHODS

A retrospective chart review was performed to identify patients with CSM who underwent surgeries from 2010 to 2014. Data collected included demographics, baseline presenting factors, and postoperative outcomes. Cervical sagittal alignment variables were measured using the preoperative and postoperative radiographs. Univariable logistic regression analyses were used to explore the association between dependent and independent variables, and a multivariable logistic regression model was created using stepwise variable selection.

RESULTS

The authors identified 171 patients who had complete preoperative and postoperative radiographic and outcomes data. The overall rate of postoperative adverse events was 33% (57/171), and postoperative C2–3 disc angle, C2–7 sagittal vertical axis, and C2–7 Cobb angle were found to be significantly associated with adverse events. Inclusion of postoperative C2–3 disc angle in the analysis led to the best prediction of adverse events. The mean postoperative C2–3 disc angle for patients with any postoperative adverse event was 32.3° ± 17.2°, and the mean for those without any adverse event was 22.4° ± 11.1° (p < 0.0001).

CONCLUSIONS

In the present retrospective analysis of postoperative adverse events in patients with CSM, the authors found a significant association between C2–3 disc angle and postoperative adverse events. They propose that C2–3 disc angle be used as an additional parameter of cervical spinal sagittal alignment and predictor for operative outcomes.
Intraoperative neurophysiological monitoring for intradural extramedullary spinal tumors: predictive value and relevance of D-wave amplitude on surgical outcome during a 10-year experience
Authors: Ghadirpour Reza , Nasi Davide , Iaccarino Corrado , Romano Antonio , Motti Luisa , Sabadini Rossella , Valzania Franco , Servadei Franco
Published: November 2018

OBJECTIVE

The purpose of this study was to evaluate the technical feasibility, accuracy, and relevance on surgical outcome of D-wave monitoring combined with somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) during resection of intradural extramedullary (IDEM) spinal tumors.

METHODS

Clinical and intraoperative neurophysiological monitoring (IONM) data obtained in 108 consecutive patients who underwent surgery for IDEM tumors at the Institute for Scientific and Care Research “ASMN” of Reggio Emilia, Italy, were prospectively entered into a database and retrospectively analyzed. The IONM included SSEPs, MEPs, and—whenever possible—D-waves. All patients were evaluated using the modified McCormick Scale at admission and at 3, 6, and 12 months of follow-up .

RESULTS

A total of 108 patients were included in this study. A monitorable D-wave was achieved in 71 of the 77 patients harboring cervical and thoracic IDEM tumors (92.2%). Recording of D-waves in IDEM tumors was significantly associated only with a preoperative deeply compromised neurological status evaluated using the modified McCormick Scale (p = 0.04). Overall, significant IONM changes were registered in 14 (12.96%) of 108 patients and 9 of these patients (8.33%) had permanent loss of at least one of the 3 evoked potentials. In 7 patients (6.48%), the presence of an s18278 caudal D-wave was predictive of a favorable long-term motor outcome even when the MEPs and/or SSEPs were lost during IDEM tumor resection. However, in 2 cases (1.85%) the D-wave permanently decreased by approximately 50%, and surgery was definitively abandoned to prevent permanent paraplegia. Cumulatively, SSEP, MEP, and D-wave monitoring significantly predicted postoperative deficits (p = 0.0001; AUC = 0.905), with a sensitivity of 85.7% and a specificity of 97%. Comparing the area under the receiver operating characteristic curves of these tests, D-waves appeared to have a significantly greater predictive value than MEPs and especially SSEPs alone (0.992 vs 0.798 vs 0.653; p = 0.023 and p < 0.001, respectively). On multiple logistic regression, the independent risk factors associated with significant IONM changes in the entire population were age older than 65 years and an anterolateral location of the tumor (p < 0.0001).

CONCLUSIONS

D-wave monitoring was feasible in all patients without severe preoperative motor deficits. D-waves demonstrated a statistically significant higher ability to predict postoperative deficits compared with SSEPs and MEPs alone and allowed us to proceed with IDEM tumor resection, even in cases of SSEP and/or MEP loss. Patients older than 65 years and with anterolateral IDEM tumors can benefit most from the use of IONM.
Iliac screw versus S2 alar-iliac screw fixation in adults: a meta-analysis
Authors: De la Garza Ramos Rafael , Nakhla Jonathan , Sciubba Daniel M. , Yassari Reza
Published: November 2018

OBJECTIVE

In a meta-analysis, the authors sought to compare outcomes after iliac screw (IS) versus S2 alar-iliac (S2AI) screw fixation in adult patients.

METHODS

A PubMed/MEDLINE database search was performed for studies comparing IS and S2AI screw fixation techniques in adults. Levels of evidence were assigned based on the North American Spine Society guidelines. Three outcomes were examined: 1) revision surgery rate secondary to mechanical failure or wound complications, 2) surgical site infection rate, and 3) screw prominence/pain. Data were pooled and outcomes compared between techniques. Absolute risk reductions (ARRs) were also calculated for outcome measures.

RESULTS

Five retrospective cohort studies (all level III evidence) were included in our analysis. A total of 323 adult patients were included—147 in the IS group (45.5%) and 176 in the S2AI group (54.5%). Overall, revision surgery due to mechanical failure or wound complications was needed in 66 of 323 patients (revision surgery rate 20.4%)—27.9% in the IS group and 14.2% in the S2AI group (13.7% ARR; p < 0.001). Four studies reported wound infections among 278 total patients, with an infection rate of 12.6% (35/278)—25.4% in the IS group and 2.6% in the S2AI group (22.8% ARR; p < 0.001). Three studies examined development of screw prominence/pain; combined, these studies reported screw prominence/pain in 21 of 215 cases (9.8%)—18.1% in the IS group and 1.8% in the S2AI group (16.3% ARR; p < 0.001).

CONCLUSIONS

S2AI screw fixation in adults has a significantly lower mechanical failure and complication rate than IS fixation based on the current best available evidence.
Effects of gamma knife radiosurgery of pituitary adenomas on pituitary function
Authors: Feigl Günther Christian , Bonelli Christine Maria , Berghold Andrea , Mokry Michael
Published: November 2018

Object. The authors undertook a retrospective analysis of the incidence and time course of pituitary insufficiency following gamma knife radiosurgery (GKS) for pituitary adenomas.

Methods. Pituitary adenomas in 92 patients were analyzed. There were 61 hormonally inactive tumors, 18 prolactinomas, and nine somatotropic and four adrenocorticotropic adenomas. The mean tumor volume was 3.8 cm3 (range 0.2–14.6 cm3). The mean prescription dose was 15 Gy. The mean prescription isodose was 50.7%.

The mean follow-up time was 4.6 years (range 1.2–10 years). The following new or deteriorating insufficiencies that did not require treatment were recorded for the different pituitary axes: follicle-stimulating hormone (FSH)/luteinizing hormone (LH) 19 (20.6%), thyroid-stimulating hormone (TSH) 32 (34.8%), adenocorticotropic hormone (ACTH) 10 (10.9%), and growth hormone (GH) 26 (28.3%). For new insufficiencies or deterioration requiring replacement therapy, the figures were as follows: FSH/LH 20 (21.7%), TSH 22 (23.9%), ACTH eight (8.7%), and GH 12 (13%). Spot dosimetry was performed in 59 patients in the hypothalamic region, the pituitary gland, and pituitary stalk. The pituitary stalks in patients with deterioration of pituitary function received a statistically higher dosage of radiation, 7.7 ± 3.7 Gy compared with 5.5 ± 3 Gy (p = 0.03).

Conclusions. The function of the residual normal pituitary gland is less affected following GKS of pituitary adenomas than after fractionated radiotherapy. Nonetheless, increased attention needs to be exercised to reduce the dose to the stalk and pituitary gland to minimize the incidence of these complications.