TEMPORAL LOBECTOMY AND ITS MODERN DERIVATIVES E15 (1) Temporal Lobectomy and its Modern Derivatives Last updated: September 9, 2021 RELEVANT ANATOMY .................................................................................................................................... 2 INDICATIONS .................................................................................................................................................. 2 CONTRAINDICATIONS .................................................................................................................................... 2 TYPES ............................................................................................................................................................. 3 PREOPERATIVE .............................................................................................................................................. 4 PROCEDURE – OPEN ...................................................................................................................................... 4 Counselling ............................................................................................................................................. 4 Anesthesia .............................................................................................................................................. 4 Positioning, Incision ............................................................................................................................... 4 Craniotomy ............................................................................................................................................. 9 Language Mapping ............................................................................................................................... 10 Resection of lateral temporal lobe ........................................................................................................ 10 Hippocampus anatomy ......................................................................................................................... 16 Resection of hippocampus ................................................................................................................... 18 Resection of amygdala ......................................................................................................................... 25 SELECTIVE AMYGDALO-HIPPOCAMPECTOMY (SAH) ............................................................................... 26 Approaches ........................................................................................................................................... 27 Criteria / Algorithm .............................................................................................................................. 30 LITT (STEREOTACTIC LASER AMYGDALOHIPPOCAMPOTOMY) ................................................................... 31 Trajectory, Targeting ............................................................................................................................ 32 In OR .................................................................................................................................................... 42 In MRI suite ......................................................................................................................................... 42 Complications ....................................................................................................................................... 44 Follow up .............................................................................................................................................. 47 Outcomes .............................................................................................................................................. 47 Trials ..................................................................................................................................................... 48 RF .............................................................................................................................................................. 48 STEREOTACTIC RADIOSURGERY (SRS) ...................................................................................................... 48 RNS ........................................................................................................................................................... 48 TRANSCORTICAL- TRANSVENTRICULAR APPROACH ................................................................................... 49 Anesthesia, position ............................................................................................................................. 50 Incision ................................................................................................................................................. 50 Trajectory / Corridor ............................................................................................................................ 51 Hippocampal resection ......................................................................................................................... 54 Pitfalls ................................................................................................................................................... 57 TRANSSYLVIAN APPROACH ........................................................................................................................ 57 SUBTEMPORAL APPROACH ......................................................................................................................... 58 Technique ............................................................................................................................................. 58 Outcomes .............................................................................................................................................. 60 MINIMALLY INVASIVE VIA TRANSPALPEBRAL ENDOSCOPIC-ASSISTED APPROACH.................................... 60 SUPRACEREBELLAR-TRANSTENTORIAL PARAMEDIAN SAH ...................................................................... 60 Advantages ........................................................................................................................................... 60 Disadvantages ....................................................................................................................................... 61 Preop ..................................................................................................................................................... 61 Anatomy, Technique ............................................................................................................................ 61 MULTIPLE HIPPOCAMPAL TRANSECTION (MHT) ........................................................................................ 65 TRANSSYLVIAN TRANSCISTERNAL AND TRANSINFERIOR INSULAR SULCUS APPROACH ............................ 65 POSTOPERATIVE .......................................................................................................................................... 65 TEMPORAL LOBECTOMY AND ITS MODERN DERIVATIVES E15 (2) COMPLICATIONS .......................................................................................................................................... 66 OUTCOMES ................................................................................................................................................... 69 SURGERY ................................................................................................................................................... 69 AED tapering ........................................................................................................................................ 70 SAH ...................................................................................................................................................... 70 Surgically refractory MTLE / Recurrent seizures / Surgery failure ..................................................... 70 SRS ........................................................................................................................................................... 72 TEMPORAL LOBE EPILEPSY – see p. E9 >> Pending sources: http://www.neurosurgicalatlas.com/volumes/epilepsy-surgery/temporal-lobe-surgery/anteromedial- temporal-lobectomy Drs. Cohen-Gadol and Spencer: https://www.youtube.com/watch?v=ILDdmVqUkag Starr, Barbaro, Larson “Neurosurgical Operative Atlas - Functional Neurosurgery” 2nd ed (2009), ch. 3, 4-5 Youmans Ch. 62 A. Olivier. Temporal resections in the surgical treatment of epilepsy. Epilepsy Res Suppl, 5 (1992), pp. 175-188 RELEVANT ANATOMY Amygdala – see p. A137 >> Hippocampus – see p. A138 >> Temporal lobe – see p. A138 >> INDICATIONS - temporal lobe epilepsies: see p. E9 >> 80% of patients with medically intractable seizures with demonstrable focus have foci in anterior temporal lobe! avoid loss of time - longer duration of epilepsy is associated with poorer postoperative seizure outcome and detrimental effect on cognitive functioning. CONTRAINDICATIONS Dominant side – always do WADA testing! 1. Dominant temporal lobe with preserved memory (on neuropsychologic testing) if there is support for memory function on nondominant side (as tested by WADA), anteromedial temporal lobe resection (AMTR) still leads to decline in verbal memory function that is noticeable