SANS Functional/stereotactic Flashcards
Pasien, 30 tahun, dengan spasme hemifasial unilateral. MRI otak diinstruksikan untuk membedakan etiologi yang mendasari gejala tersebut. Berapa persentase yang dapat teridentifikasi sebagai penyebab selain kompresi vaskular di tempat keluar nervus fasialis?
A. 6-8 %
B. 3-5 %
C. 10 %
C.
Pasien, 42 tahun memiliki riwayat penyakit Parkinson sejak 5 tahun lalu dengan fluktuasi motorik berat. Ketika mendiskusikan tentang metode operasi “deep brain stimulation” (DBS), manakah di bawah ini yang benar mengenai manfaat operasi tersebut?
A. Penurunan “OFF time freezing” dari gejala gait sebagai hasil DBS
B. Akan memiliki ≥ 4 jam “ON time” tanpa diskinesia setiap harinya.
C. DBS akan menghilangkan kebutuhan akan terapi medikamentosa
D. Intervensi bedah sejak dini akan merubah riwayat alamiah dari penyakit
E. Riwayat penyakit belum cukup lama untuk mendapatkan keuntungan dari tindakan operasi
B. Akan memiliki ≥ 4 jam “ON time” tanpa diskinesia setiap harinya.
In recent multicenter long term studies, patients experience up to 4 hours more ON time without dyskinesias. DBS for PD is considered an adjunctive treatment to medications. Based on randomized clinical trials, medications can be reduced up to 20-40% over time, but in most instances, they are not eliminated. However, the frequency with which they need to be taken is reduced, reducing the on/off motor fluctuations commonly experienced. Deep brain stimulation only improves levodopa responsive symptoms including bradykinesia and rigidity as well as tremor. OFF-time freezing of gait, postural instability and non-motor symptoms of PD do not improve and can worsen with DBS surgery. DBS has NOT been shown to modulate the natural history of PD. Duration of disease is not a primary criteria for surgical selection, although symptoms should persist long enough to be confident of the diagnosis of PD.
Pasien, seorang pria berusia 45 tahun dengan riwayat “intention tremor” yang progresif pada lengan kanan sejak 5 tahun lalu. Gejala yang sama juga didapatkan pada ayah dan paman dari pihak ayah. Tremor meningkat dengan konsumsi alkohol dan menjadi semakin refrakter dengan pemberian Propanolol, Mysoline, serta Topamax. Tidak ada rigiditas, bradikinesia, atau kelainan gaya berjalan saat ini. Intervensi bedah saraf yang PALING TEPAT adalah:
A. “Thalamic deep brain stimulator”
B. “Globus pallidus deep brain stimulator”
C. “C6,7 selective rhizotomy”
D. “Stereotatic pallidotomy”
E. “Subthalamic nucleus deep brain stimulator”
A. “Thalamic deep brain stimulator”
The patient described above has the clinical signs and symptoms of benign essential tremor. He has no other symptoms to suggest Parkinson’s disease. When essential tremor is refractory to the appropriate medical therapy, a neurosurgical intervention may be indicated. The preferred target for essential tremor is the Ventral Intermediate (Vim) nucleus of the thalamus. Either chronic stimulation via implanted electrodes (deep brain stimulation, DBS) or lesioning (thalamotomy) of the hemisphere contralateral to the affected limb can be performed. DBS has the advantages of adjustability and reversibility, but carries with it the risk of hardware-related complications such as infection, lead migration, or lead fracture. Globus pallidus is a target (of lesion or stimulation) in Parkinson’s disease and the subthalamic nucleus is a target of stimulation in Parkinson’s disease. Selective cervical rhizotomy does not play a role in essential tremor management.
Seorang pasien berusia 63 tahun dengan penyakit Parkinson yang responsif dengan levodopa dianjurkan untuk “deep brain stimulation” (DBS). Sehubungan dengan gejala motorik, DBS kemungkinan bermanfaat untuk?
A. Peningkatan “ON time” pada diskinesia yang bermasalah
B. Penurunan “OFF time”
C. Memiliki efek minimal pada hasil “Unified Parkinson’s Disease Rating Scale” (UPDRS) III scores
D. Memperbaiki gejala gait
E. Menurukan “freezing events”
B. Penurunan “OFF time”
DBS can be expected to decrease “off” time.
Two recent RCTs have studied the effect of the addition of DBS to best medical therapy on motor scores for PD patients. Weaver et al. (2009) showed that DBS (of either the STN or GPi) improved several measures of motor symptoms, including decreasing “off” time, increasing “on” time without troubling dyskinesias, decreasing “on” time with troubling dyskinesias, and improving UPDRS III scores in patients off medication. Gait disturbance and freezing events were not endpoints of the study, but were recorded as adverse events, with no statistical significance between the groups.
Deuschl et al. (2006) showed that the addition of DBS to medical therapy was associated with significant improvements in UPDRS III scores.
Both those studies also noted significant improvement in quality of life measures for the DBS group. Another recent study (Williams et al., 2010) focused on quality of life differences between DBS + best medical therapy vs. best medical therapy alone, and again found a significant advantage for the patients receiving DBS.
Seorang pasien sedang menjalani “deep brain stimulation” (DBS) dengan penempatan lead di bagian nukleus subthalamus pada penyakit Parkinson. Dalam penilaian intraoperatif, selain didapatkan perbaikan pada gejala, perlu diperhatikan juga adanya penarikan dari raut wajah dan parestesia yang sifatnya sementara. Prosedur menggunakan monopolar dan bipolar menghasilkan hasil yang sama. Manakah dibawah ini yang merupakan pilihan yang tepat dalam kasus ini?
A. Perdarahan Subdural
B. Selesaikan prosedur DBS sampai di sana
C. Pindahkan lead ke lateral
D. Pindahkan lead ke medial
E. Batalkan implantasi di daerah ini dan lakukan prosedur implantasi DBS di bagian kiri
E. Batalkan implantasi di daerah ini dan lakukan prosedur implantasi DBS di bagian kiri
Spread of current to the internal capsule resulting in contractions of the contralateral side of the face or extremity is one of the most common limitations to DBS programming. Clear contractions are seen at the same amplitudes that will be used for symptom suppression and these will likely persist during postoperative programming. The internal capsule is situated lateral and anterior to the subthalamic nucleus. Contractions observed during macrostimulation usually indicate lateral placement of the lead and/or anterior placement of the lead. In this case, transient paresthesias indicate that the lead is more posteriorly placed in the nucleus and not too far anterior. Moving the lead to a more medial location will likely reduce spread of current to the capsule and facilitate programming.
Seorang pasien dengan riwayat sebelumnya terimplantasi dengan “deep brain stimulation” (DBS) bilateral membutuhkan MRI di daerah panggul. Manakah dibawah ini yang benar mengenai kompabilitas dan keamanan penggunaan MRI pada kasus tersebut?
A. Generator harus dilepaskan tetapi lead pada otak dapat dibiarkan pada tempatnya
B. MRI dapat dilakukan dengan aman apabila sistem DBS diposisikan pada 0 volts, OFF, dan bipolar.
C. Pelepasan sistem DBS terlebih dahulu dibutuhkan untuk memperoleh gambaran MRI dengan penggunaan body coil
D. MRI memiliki risiko minimal terhadap rusaknya sistem DBS tapi tidak memiliki risiko apapun terhadap otak dan badan pasien.
E. Menghasilkan lebih banyak pasien dengan status vegetatif pada akhir masa pengobatan
C. Pelepasan sistem DBS terlebih dahulu dibutuhkan untuk memperoleh gambaran MRI dengan penggunaan body coil
MRI with a body coil is always contraindicated for patients with DBS systems. MRI may be safe for head examinations utilizing only a head transmit-receive coil in 1.5 Tesla MRI equipment, if strict guidelines for SAR are followed and if the DBS has no suspected open or short circuits. In addition to turning OFF the stimulation, the programming settings have to be changed and these will depend on the stimulator model. Consult labeling specific to the hardware befoer performing an MRI in a patient implanted with a neurostimulation system.
Efek samping yang dapat timbul dari ekstensi inferior dari lesi terapeutik yang ditempatkan pada globus pallidus posteroventral pars internus adalah?
A. Hemiballism B. Ataksia C. Gangguan sensorik D. Hemiplegia E. Penurunan lapang pandang
E. Penurunan lapang pandang
The optic tract passes immediately subjacent to the posteroventral globus pallidus pars internus and may be injured during posteroventral pallidotomy. Hemiballism is associated with lesions in the region of the subthalamic nucleus. Sensory loss can occur with extension of a thalamotomy lesion into the ventrocaudal nucleus, which lies immediately posterior to the ventrolateral nucleus in the thalamus. Finally, hemiplegia can occur with pallidotomy lesions that extend too far posteriorly or medially.
Ketika melakukan stimulasi sumsum tulang belakang untuk pasien dengan “failed back surgery syndrome” dan nyeri kronik pada tungkai bawah kanan, dimanakah elektroda harus diletakkan?
A. Paramedian kanan pada “thoracic epidural sublaminar space”
B. Paramedian kiri pada “lumbar epidural sublaminar space”
C. Paramedian kanan pada “lumbar epidural sublaminar space”
D. Paramedian kiri pada “thoracic epidural sublaminar space”
A. Paramedian kanan pada “thoracic epidural sublaminar space”
Spinal cord stimulation is a treatment modality aimed at alleviating-but not curing-chronic pain, in particular neuropathic pain. Failed back surgery syndrome after lumbar surgery/fusion is one of the most common indications for spinal cord stimulation in the United States. Although the lumbosacral roots are likely involved in a patient with unilateral leg pain that persists after lumbar surger, the SCS lead(s) is typically not placed at the level of the cauda equina. Rather, SCS is aimed at the dorsal columns typically at the lower thoracic spine. Spinal cord stimulation typically produces paresthesias over the area of pain. Mechanosensory fibers that course through the dorsal columns-unlike pain and temperature fibers-do not decussate at the level of entry in the spinal cord. Rather, the decussation occurs at the level of the medial lemniscus. Hence, in order to affect the right lower extremity and produce right lower extremity paresthesias, the active contacts have to stimulate predominantly the right dorsal column.
