The collages shown on this page, derived from patients operated by Dr Khurana, show some of the more dangerous entities a neurosurgeon can encounter. The conditions illustrated here are considered to be "higher-risk" for the reasons stated in the figure legends below. Vini Khurana specialises in micro-surgery for high-risk neurosurgical conditions. All of the following patients made excellent recoveries postoperatively.

PATIENT 1 - MALIGNANT (WHO Grade 3 of 3) OLIGODENDROGLIOMA

This teenager presented to our Emergency Department with progressive headaches, vomiting, and memory impairment. A. MRI scan of the brain showed a very large and infiltrative brain tumour (T; white and grey areas in red circle) located in the "dominant" temporal lobe, with considerable brain swelling (oedema). It was causing life-threatening compression of the brainstem (green arrow head) referred to as uncal (U) herniation. The mass encroaches upon regions serving memory & learning, hearing and language, field of vision, and limb movement, B. The boy's preoperative imaging included MR tractography, in order to assess the proximity of the tumour to his critical "limb movement" and "visual field" pathways deep within the brain. C. The boy was taken to the operating room, and while awake and comfortable ("awake craniotomy"), the tumour (T) was nearly totally removed while his language and movement functions were repetitively assessed in real-time by the anaesthetic team during the surgery. The tumour was infiltrative and malignant (a brain cancer) and therefore every tumour cell could not be removed surgically. D. However, the postoperative MRI scan showed near-complete removal of the tumour mass (now just a surgical cavity outlined by the red circle). The is no longer any compression of the brainstem (green arrow head). The child's symptoms all resolved, he was completely neurologically intact within a few days of surgery, and he returned to school within a few weeks of completing post-operative brain radiotherapy.

PATIENT 2 - LARGE, RUPTURED CAVERNOUS MALFORMATION (Cavernoma) OF THE BRAINSTEM

This man was referred to our Clinic from interstate with a symptomatic ruptured brainstem "cavernous malformation" or "cavernoma", a clump of leaky blood vessels that can grow and progressively debilitate a person by repeated haemorrhages. The patient had encountered episodic left-sided face numbness, hearing impairment and incoordination. A. MRI scan of the brain showed a large cavernoma (encircled in red) located in a part of the brainstem called the "pons". The critical "basilar artery" (tip of red arrow head) and the 7th and 8th cranial nerves (green arrow head) are seen near this brainstem cavernoma. The brainstem is the "highest-price real-estate" of the brain and is a challenge to safely approach and operate on. B. Intraoperative view of the patient's pons, with veins (2 mm diameter) on the right of this image, while on the left there are cranial nerves 7 (for facial muscle movement) and 8 (for hearing and balance). C. A small incision has been made into the pons, and the cavernoma's blood-stained cavity is now on view (in black circle). D. The cavernoma has been removed, and the surrounding discoloured brainstem tissue is seen. E & F. The preoperative and postoperative MRI (T1 sequence+contrast) sequences are shown here side-by-side. The cavernoma and haemorrhage products (between green arrow heads) were removed; some small amount of blood products remained, absorbed in time. In F., A "developmental venous anomaly" (DVA) or "venous angioma" (red arrow heads) is seen next to the previous cavernoma cavity; this DVA was intentionally not removed as it represents part of the normal venous drainage of this patient's brainstem. G. Postoperative CT scan image showing some small amount of blood products and a little air in the resection cavity which typically absorb in time. The patient was neurologically intact within 48 hours of surgery.

PATIENT 3 - SPETZLER-MARTIN GRADE 4 ARTERIOVENOUS MALFORMATION (AVM) OF THE TORCULA REGION

This man presented to our Clinic with increasing frequency and severity of headaches associated with a "bright sparks" visual phenomenon. A. MRI scan of the brain showed an arteriovenous malformation (AVM) of the brain, located in the dominant visual cortex. B. Preoperative cerebral angiogram shows the high-flow AVM cluster or "nidus" (encircled in red) to be centred around the most vascular part of the brain known as the torcula herophili (T). Any haemorrhage here (either preoperative or at the time of surgery) might be expected to be catastrophic, making this a "high-risk" condition. The large and abnormal veins (green arrow heads) draining from the AVM enter large-bore venous channels around the brain such as the superior sagittal sinus, vein of Galen/straight sinus, and transverse/sigmoid sinuses. C. Intraoperative photograph shows the nidus exposed. As expected, it looks like an engorged "bag of worms". D. Imaged under fluorescence videoangiography at the time of craniotomy, the nidus is studied for its blood flow characteristics and then sequentially shut down micro-surgically using titanium microclips. E. Postoperative cerebral angiogram showing no residual nidus, i.e., complete exicision of the AVM (previously in a location marked by the red circle). Postoperatively, the patient experienced a partial defect in the right field of vision which improved substantially within a few months of surgery. He leads a healthy and active life with no further symptoms, and no further risk of haemorrhage from what was an otherwise dangerous rupture-prone AVM.

PATIENT 4 - LARGE, RUPTURED ANEURYSM OF THE BASILAR ARTERY APEX

This older lady presented to our Emergency Department with a very severe "thunderclap" headache and became drowsy a short while later. A. CT scan of the brain showed a small haemorrhage (red circle) in front of the top of the patient's brainstem. B. A cerebral angiogram confirmed the presence of a large brain aneurysm of the main brainstem artery known as the basilar artery (red arrow head). Treating such an aneurysm without causing a life-threatening secondary brainstem stroke is a formidable neurosurgical challenge. C. Preoperative 3D CT-angiography shows a blister or "daughter sac" (green arrow head) arising from the main dome of the aneurysm (red circle). The daughter sac is the region most likely responsible for the patient's haemorrhage. The aneurysm has a wide neck making it even more difficult to treat. D. The patient was taken to the operating room, and the first of two surgical clips (green arrow head) was placed across the expanded "neck" of the aneurysm. Consistent with the fragile and unstable nature of these entities, the aneurysm ruptured again intraoperatively, and a second clip was placed. An ultrasound probe (US) is being used to measure blood flow in a critical artery adjacent to the aneurysm, in order to confirm that the surrounding arteries are still open as intended. E. The aneurysm has been obliterated by surgical clipping (green arrow heads show the two clips placed across the neck of the aneurysm; red arrow head shows top of the basilar artery). The surrounding arteries have not been compromised by the clips. The patient made a complete neurological recovery within a few weeks of her haemorrhage and emergency surgery.

PATIENT 5 - GIANT PARIETAL LOBE MENINGIOMA INVOLVING THE SUPERIOR SAGITTAL SINUS (Jehovah's Witness)

This young man presented to our Emergency Department with profound weakness and drowsiness, and was in a "moribund" condition prior to surgery. He had a history of brain radiation for a previous brain cancer as a child, and prior to his coming to our attention, had experienced several years of progressive personality changes according to his family members. He is a Jehovah's Witness. From a surgical perspective, the most important challenge that this fact presents is that no blood transfusion is permitted. A. His brain MRI showed a small cavernoma (red arrow head) and immediately behind it, a very large solid brain tumour (Tu). Cavernomas and solid tumours can arise spontaneously, or years after radiation of the brain (in some people). B. On another MRI sequence (T1 w contrast; coronal plane), the massive tumour is seen. It is a giant meningioma, most often benign, but if large enough, an obvious threat to the quality and quantity of life can arise. This patient's meningioma invades a critical venous structure of the brain called the superior sagittal sinus, adding to the challenges of this operation. The tumour has caused a reaction in the overlying skull (hyperostosis) leading to deformity of the patient's skull contour here (between green arrow heads). This very vascular tumour has caused compression of the nearby fluid filled space of the brain (lateral ventricle; yellow arrow head). C. The giant tumour (between blue arrow heads) was removed surgically, meticulously, using several blood-conserving measures. D. The postoperative scan shows complete removal of the brain tumour. Because the overlying portion of the skull was deformed and altered by the underlying attached meningioma, this portion of the skull had to be removed. However, in its place, a solid bone-cement cranioplasty (green arrow head) has been custom-made and placed in order to restore the cosmetic (symmetry) and structural (strength) integrity of the patient's skull. The yellow arrow head shows the re-expanded fluid filled space (ventricle) now that the tumour has been removed (compare preop image, B.). The patient recovered very well postoperatively.

PATIENT 6 - RUPTURED DURAL ARTERIOVENOUS FISTULA (DAVF) OF THE TORCULA REGION

This man presented to our Emergency Department with headache and vomiting. A. The CT scan showed a haemorrhage into the cerebellar region at the back lower part of the brain. B. CT angiography revealed a rare high-blood flow communication between local arteries and veins (e.g., venous sac highlighted by red arrow head) in this location referred to as a dural arteriovenous fistula (DAVF). The abormality drains into the adjacent highest blood-flow structure of the brain known as the torcula herophili (T), which receives blood from the straight (St) and superior sagittal (Su) venous sinuses. If there is any injury of this structure during surgery, death will most likely be the outcome. Immediately prior to surgery, the patient experienced a rehaemorrhage and hydrocephalus (build up of brain fluid pressure). C. The intraoperative photograph shows the fistula's veins being surgically clipped and shut down, without any injury to the tocula or compromise of its surrounding venous sinuses. D. The preoperative cerebral angiogram shows the fistula (red circle) with its robust capillary communication between the green arrow heads, and part of its drainage (red arrow head). E. The fistula is no longer present postoperatively (red circle void), and the patient made a complete neurological recovery. OA = occipital artery (the main blood supply origin of this fistula).

PATIENT 7 - CERVICOMEDULLARY CAVERNOMA

This young patient was referred with progressive weakness of all limbs (quadraparesis) and impaired bowel and bladder function. Without the appropriate surgical treatment, she would soon have become severely disabled. A. The preoperative MRI scan showed a cavernoma/cavernous haemangioma (in red circle) involving the lower brain stem (medulla) and uppper (cervical) spinal cord. Green arrow heads show the characteristic haemosiderin or iron pigment (dark staining here) deposited into the brain and spinal cord tissue by this long-standing cavernoma that had been subtly leaking blood for some time. B. Advanced MRI imaging using MR tractography software shows the region of the cavernoma (red circle) and the haemosiderin pigment (green arrow heads) and their relationship to the key movement pathyway of the limbs (corticospinal tract; shown in bright blue here as it passes through the brainstem and spinal cord). This cavernoma and its blood products displaced and squashed ("effaced") this critical tract causing much of the patient's debilitation prior to surgery. C. The intraoperative photograph shows the multiple small rasberry-like "caverns of blood" (sinusoids) of the cavernoma (in red circles) once an opening was very carefully made in the brainstem and spinal cord and the overlying membranes. The C1 and C2 nerve roots can be seen (yellow arrow heads). D. The postoperative MRI shows that the cavernoma has been removed. The haemosiderin pigment remains (this cannot be safely removed from the brainstem as viable nerve tissue exists in this highly eloquent area and must be preserved). The curative goal is removing the cavernoma. The patient is recovering very well postoperatively.