Gamma Knife stereotactic radiosurgery for idiopathic trigeminal neuralgia

OBJECT

Trigeminal neuralgia pain causes severe disability. Stereotactic radiosurgery is the least invasive surgical option for patients with trigeminal neuralgia. Since different medical and surgical options have different rates of pain relief and morbidity, it is important to evaluate longer-term outcomes.

METHODS

The authors retrospectively reviewed outcomes in 503 medically refractory patients with trigeminal neuralgia who underwent Gamma Knife surgery (GKS). The median patient age was 72 years (range 26-95 years). Prior surgery had failed in 205 patients (43%). The GKS typically was performed using MR imaging guidance, a single 4-mm isocenter, and a maximum dose of 80 Gy.

RESULTS

Patients were evaluated for up to 16 years after GKS; 107 patients had > 5 years of follow-up. Eighty-nine percent of patients achieved initial pain relief that was adequate or better, with or without medications (Barrow Neurological Institute [BNI] Scores I-IIIb). Significant pain relief (BNI Scores I-IIIa) was achieved in 73% at 1 year, 65% at 2 years, and 41% at 5 years. Including Score IIIb (pain adequately controlled with medication), a BNI score of I-IIIb was found in 80% at 1 year, 71% at 3 years, 46% at 5 years, and 30% at 10 years. A faster initial pain response including adequate and some pain relief was seen in patients with trigeminal neuralgia without additional symptoms, patients without prior surgery, and patients with a pain duration of < or = 3 years. One hundred ninety-three (43%) of 450 patients who achieved initial pain relief reported some recurrent pain 3-144 months after initial relief (median 50 months). Factors associated with earlier pain recurrence that failed to maintain adequate or some pain relief were trigeminal neuralgia with additional symptoms and > or = 3 prior failed surgical procedures. Fifty-three patients (10.5%) developed new or increased subjective facial paresthesias or numbness and 1 developed deafferentation pain; these symptoms resolved in 17 patients. Those who developed sensory loss had better long-term pain control (78% at 5 years).

CONCLUSIONS

Gamma Knife surgery proved to be safe and effective in the treatment of medically refractory trigeminal neuralgia and is of value for initial or recurrent pain management. Despite the goal of minimizing sensory loss with this procedure, some sensory loss may improve long-term outcomes. Pain relapse is amenable to additional GKS or another procedure.

T1/T2 matching to differentiate tumor growth from radiation effects after stereotactic radiosurgery

OBJECTIVE

We define magnetic resonance imaging (MRI) and clinical criteria that differentiate radiation effect (RE) from tumor progression after stereotactic radiosurgery (SRS).

METHODS

We correlated postoperative imaging and histopathological data in 68 patients who underwent delayed resection of a brain metastasis after SRS. Surgical resection was required in these patients because of clinical and imaging evidence of lesion progression 0.3 to 27.7 months after SRS. At the time of SRS, the median target volume was 7.1 mL (range, 0.5-26 mL), which increased to 14 mL (range, 1.3-81 mL) at the time of surgery. After initial SRS, routine contrast-enhanced MRI was used to assess tumor response and to detect potential adverse radiation effects. We retrospectively correlated these serial MRIs with the postoperative histopathology to determine if any routine MRI features might differentiate tumor progression from RE.

RESULTS

The median time from SRS to surgical resection was 6.9 months (range, 0.3-27.7 months). A shorter interval from SRS to resection was associated with a higher rate of tumor recurrence (P = .014). A correspondence between the contrast-enhanced volume on T1-weighted images and the low signal-defined lesion margin on T2-weighted images ("T1/T2 match") was associated with tumor progression at histopathology (P < .0001). Lack of a clear and defined lesion margin on T2-weighted images compared to the margin of contrast uptake on T1-weighted images ("T1/T2 mismatch") was significantly associated with a higher rate of RE in pathological specimens (P < .0001). The sensitivity of the T1/T2 mismatch in identifying RE was 83.3%, and the specificity was 91.1%.

CONCLUSIONS

We found that time to progression and T1/T2 mismatch were able to differentiate tumor progression from RE in most patients. When REs are suspected, surgery may not be necessary if patients respond to conservative measures. When tumor progression is suspected, resection or repeat radiosurgery can be effective, depending on the degree of mass effect.

GAMMA KNIFE RADIOSURGERY IN YOUNGER PATIENTS WITH VESTIBULAR SCHWANNOMAS

OBJECTIVE

Management options for patients with vestibular schwannoma include observation, surgical resection, stereotactic radiosurgery (SRS), and stereotactic radiation therapy. In younger patients, resection is often advocated because of concern regarding the long-term effects of radiation. We studied tumor response and clinical outcomes after SRS in such patients.

METHODS

We reviewed long-term outcomes in 55 patients with vestibular schwannomas. Patients were 40 years of age or younger, underwent gamma knife (GK) SRS between 1987 and 2003, and were followed up for a minimum of 4 years. The median patient age was 35 years (range, 13–40 years). Forty-one patients had Gardner-Robertson class 1 to 4 hearing. Thirteen patients (24%) had undergone surgical removal. The median tumor volume was 1.7 mm3. The median tumor margin dose was 13.0 Gy (range, 11–20 Gy).

RESULTS

At a median of 5.3 years, (range, 4–20 years), 2 of 55 patients underwent GK SRS for a second time; 1 of these patients had had a recurrence after initial resection. The 5-year rate of freedom from additional management was 96%. Hearing preservation rates (i.e., remaining within the same Gardner-Robertson hearing class) were 93%, 87%, and 87% at 3, 5, and 10 years, respectively. In patients with serviceable hearing before SRS, it was maintained in 100%, 93%, and 93% of patients at 3, 5, and 10 years, respectively. Hearing preservation was related to a margin dose lower than 13 Gy (P = 0.017). At the last assessment, facial and trigeminal nerve function was preserved in 98.2% and 96.4% of patients, respectively; the only facial deficit (House-Brackmann grade III) occurred in a patient who received a tumor dose of 20 Gy early in our experience (1988). None of the patients treated with doses lower than 13 Gy experienced facial or trigeminal neuropathy. All patients continued their previous level of activity or employment after GK SRS. No patient developed a secondary radiation-related tumor.

CONCLUSION

Our experience indicates that GK SRS is an effective management strategy for younger patients with vestibular schwannoma, most of whom have no additional cranial nerve dysfunction.

Gamma knife radiosurgery for multiple sclerosis-related trigeminal neuralgia

BACKGROUND

Surgical options for multiple sclerosis (MS) related to trigeminal neuralgia (TN), a severe and disabling pain disorder, include percutaneous rhizotomy, stereotactic radiosurgery, or microsurgical nerve section. Our goal was to evaluate clinical outcomes after gamma knife radiosurgery (GKRS) in patients with MS with TN.

METHODS

We evaluated clinical outcomes in 37 patients with TN managed over a 12-year period. The maximum TN target dose varied between 70 and 90 Gy. Seventy-eight percent of patients had failed prior surgery. In 9, GKRS was the first procedure. Median follow-up was 56.7 months (range, 6-174). Pain relief was assessed in each patient by physicians who did not participate in the surgery.

RESULTS

Eventual complete pain relief (BNI grade I) after GKRS and reasonable pain control (BNI grade I-IIIb) after GKRS were noted in 23 patients (62.1%) and 36 patients (97.3%) at some point in their course. Reasonable pain control (BNI grade I-IIIb) after GKRS was maintained in 82.6%, 73.9%, and 54.0% of patients after 1, 3, and 5 years. Fourteen patients (37.8%) underwent a second or a subsequent procedure for residual or recurrent pain. Eight patients underwent a second GKRS, 5 underwent percutaneous glycerol rhizotomy, and 1 underwent balloon microcompression. The complication rate after GKRS was 5.4% (new onset of nondisabling paresthesias). No patient developed dysesthesias.

CONCLUSIONS

Gamma knife radiosurgery is the most minimally invasive surgical technique for multiple sclerosis-related trigeminal neuralgia and has low morbidity. For this reason, gamma knife radiosurgery proved to be a satisfactory management strategy for multiple sclerosis-related trigeminal neuralgia.

Outcome predictors after gamma knife radiosurgery for recurrent trigeminal neuralgia

BACKGROUND

Trigeminal neuralgia (TN) that recurs after surgery can be difficult to manage.

OBJECTIVE

To define management outcomes in patients who underwent gamma knife stereotactic radiosurgery (GKSR) after failing 1 or more previous surgical procedures.

METHODS

We retrospectively reviewed outcomes after GKSR in 193 patients with TN after failed surgery. The median patient age was 70 years (range, 26-93 years). Seventy-five patients had a single operation (microvascular decompression, n=40; glycerol rhizotomy, n=24; radiofrequency rhizotomy, n=11). One hundred eighteen patients underwent multiple operations before GKSR. Patients were evaluated up to 14 years after GKSR.

RESULTS

After GKSR, 85% of patients achieved pain relief or improvement (Barrow Neurological Institute grade I-IIIb). Pain recurrence was observed in 73 of 168 patients 6 to 144 months after GKSR (median, 6 years). Factors associated with better long-term pain relief included no relief from the surgical procedure preceding GKSR, pain in a single branch, typical TN, and a single previous failed surgical procedure. Eighteen patients (9.3%) developed new or increased trigeminal sensory dysfunction, and 1 developed deafferentation pain. Patients who developed sensory loss after GKSR had better long-term pain control (Barrow Neurological Institute grade I-IIIb: 86% at 5 years).

CONCLUSION

GKSR proved to be safe and moderately effective in the management of TN that recurs after surgery. Development of sensory loss may predict better long-term pain control. The best candidates for GKSR were patients with recurrence after a single failed previous operation and those with typical TN in a single trigeminal nerve distribution.

The results of resection after stereotactic radiosurgery for brain metastases

Object

Radiosurgery for brain metastasis fails in some patients, who require further surgical care. In this paper the authors' goal was to evaluate prognostic factors that correlate with the survival of patients who require a resection of a brain metastasis after stereotactic radiosurgery (SRS).

Methods

During the last 14 years when surgical navigation systems were routinely available, the authors identified 58 patients who required resection for various brain metastases after SRS. The median patient age was 54 years. Prior adjuvant treatment included whole-brain radiation therapy alone (17 patients), chemotherapy alone (9 patients), both radiotherapy and chemotherapy (10 patients), and prior resection before SRS (8 patients). The median target volumes at the time of SRS and resection were 7.7 cm3 (range 0.5–24.9 cm3) and 15.5 cm3 (range 1.3–81.2 cm3), respectively.

Results

At a median follow-up of 7.6 months, 8 patients (14%) were living and 50 patients (86%) had died. The survival after surgical removal was 65, 30, and 16% at 6, 12, and 24 months, respectively (median survival after resection 7.7 months). The local tumor control rate after resection was 71, 62, and 43% at 6, 12, and 24 months, respectively. A univariate analysis revealed that patient preoperative recursive partitioning analysis classification, Karnofsky Performance Scale status, systemic disease status, and the interval between SRS and resection were factors associated with patient survival. The mortality and morbidity rates of resection were 1.7 and 6.9%, respectively.

Conclusions

In patients with symptomatic mass effect after radiosurgery, resection may be warranted. Patients who had delayed local progression after SRS (> 3 months) had the best outcomes after resection.

The reverse question mark and L.G. Kempe incisions for decompressive craniectomy: A case series and narrative review of the literature

Background:

Decompressive craniectomy (DC) is a lifesaving procedure, relieving intracranial hypertension. Conventionally, DCs are performed by a reverse question mark (RQM) incision. However, the use of the L. G. Kempe’s (LGK) incision has increased in the last decade. We aim to describe the surgical nuances of the LGK and the standard RQM incisions to treat patients with severe traumatic brain injury (TBI), intracranial hemorrhage (ICH), empyema, and malignant ischemic stroke. Furthermore, to describe, surgical limitations, wound healing, and neurological outcomes related to each technique.

Methods:

To describe a prospective acquired, case series including patients who underwent a DC using either an RQM or an LGK incision in our institution between 2019 and 2020.

Results:

A total of 27 patients underwent DC. Of those, ten patients were enrolled. The mean age was 42.1 years (26–71), and 60% were male. Five patients underwent DC using a large RQM incision; three had severe TBI, one ICH, and one ischemic stroke. The other five patients underwent DC using an LGK incision (one ICH, one subdural empyema, and one ischemic stroke). About 50% of patients presented severe headaches associated with vomiting, and six presented altered mental status (drowsy or stuporous). Motor deficits were present in four cases. In patients with ischemic or hemorrhagic stroke, symptoms were directly related to the stroke location. Hospital stays varied between 13 and 22 days. No readmissions were recorded, and no fatal outcome was documented during the follow-up.

Conclusion:

The utility of the LGK incision is comparable with the classic RQM incision to treat acute brain injuries, where an urgent decompression must be performed. Some of these cases include malignant ischemic strokes, ICH, and empyema. No differences were observed between both techniques in terms of prevention of scalp necrosis and general cosmetic outcomes.

Cellular Senescence in Diffuse Gliomas: From Physiopathology to Possible Treatments

Cellular senescence in gliomas is a complex process that is induced by aging and replication, ionizing radiation, oncogenic stress, and the use of temozolomide. However, the escape routes that gliomas must evade senescence and achieve cellular immortality are much more complex, in which the expression of telomerase and the alternative lengthening of telomeres, as well as the mutation of some proto-oncogenes or tumor suppressor genes, are involved. In gliomas, these molecular mechanisms related to cellular senescence can have a tumor-suppressing or promoting effect and are directly involved in tumor recurrence and progression. From these cellular mechanisms related to cellular senescence, it is possible to generate targeted senostatic and senolytic therapies that improve the response to currently available treatments and improve survival rates. This review aims to summarize the mechanisms of induction and evasion of cellular senescence in gliomas, as well as review possible treatments with therapies targeting pathways related to cellular senescence.

Decompressive Craniectomy and Hinged Craniotomy for Traumatic Brain Injury: Experience in Two Centers in a Middle-Income Country

Objective

The goal of a decompressive craniectomy (DC) or a hinge craniotomy (HC), is to treat intracranial hypertension and reduce mortality. Traditionally, the decompression procedure has been performed with cranial bone removal. However, decompression and repositioning the cranial bone, named HC, has been presented as an alternative for certain cases. Our objective is to describe the neuroradiological and clinical preoperative factors and outcomes in traumatic brain injury (TBI) cases treated with both techniques in 2 centers in a Middle-Income country.

Methods

This is a retrospective cross-sectional study of adult patients who underwent decompression surgical treatment for TBI, either with a traditional DC or HC, in 2 centers in Bogotá, Colombia between 2016-2020.

Results

This study involved 30 cases that underwent HC and 20 that underwent DC. 78% were male with an overall mean age of 50.2 years. 66% cases had traumatic subarachnoid hemorrhage (tSAH) and 60% had evidence of acute subdural hematoma ≥10 mm in thickness. The overall mortality rate during hospitalization was 20%. Preoperative pupil impairment differences between the 2 groups were statistically significant (p=0.026).

Conclusion

This study reveals that using a traditional DC or HC depends on the neurosurgeon's intraoperative case-by-case assessment according to the intraoperative brain's vitality and the presence of diffuse edema in the brain parenchyma at the time of surgical closure. Each case requires an individualized evaluation before and during surgery. The preoperative pupil condition can serve as a marker for HC or DC selection.

Resting state networks in patients with acute disorders of consciousness after severe traumatic brain injury

OBJECTIVES

This study aims to describe resting state networks (RSN) in patients with disorders of consciousness (DOC)s after acute severe traumatic brain injury (TBI).

METHODS

Adult patients with TBI with a GCS score <8 who remained in a coma, minimally conscious state (MCS), or unresponsive wakefulness syndrome (UWS), between 2017 and 2020 were included. Blood-oxygen-level dependent imaging was performed to compare their RSN with 10 healthy volunteers.

RESULTS

Of a total of 293 patients evaluated, only 13 patients were included according to inclusion criteria: 7 in coma (54%), 2 in MCS (15%), and 4 (31%) had an UWS. RSN analysis showed that the default mode network (DMN) was present and symmetric in 6 patients (46%), absent in 1 (8%), and asymmetric in 6 (46%). The executive control network (ECN) was present in all patients but was asymmetric in 3 (23%). The right ECN was absent in 2 patients (15%) and the left ECN in 1 (7%). The medial visual network was present in 11 (85%) patients. Finally, the cerebellar network was symmetric in 8 patients (62%), asymmetric in 1 (8%), and absent in 4 (30%).

CONCLUSIONS

A substantial impairment in activation of RSN is demonstrated in patients with DOC after severe TBI in comparison with healthy subjects. Three patterns of activation were found: normal/complete activation, 2) asymmetric activation or partially absent, and 3) absent activation.