Dalcross Minimally Invasive Surgery

Minimally-Invasive Surgery- Cranial and Spinal Procedures

A.Prof. Lali Sekhon

Current technologies in neurosurgery/spinal surgery allows the surgeon, in select circumstances, to perform surgery through small incisions and approaches (minimally-invasive surgery or "key-hole" surgery). This can lessen postoperative pain and scarring, and hasten recovery. The following are 3 examples of minimally invasive cases performed this year at Dalcross Private Hospital, which illustrate the application of minimally invasive techniques to both intracranial and spinal problems.

Case 1 - Endoscopic 3rd Ventriculostomy

Case 2 - Lumbar Endoscopy

Case 3 - Multiple Key-hole Craniotomies for Tumour

Case 1: Endoscopic 3rd Ventriculostomy

History

A 30 year old man was admitted to Dalcross Hospital after a several week history of headaches and subsequent nausea and vomiting. On arrival to the emergency room at Royal North Shore Hospital, he was unconscious with a GCS of 8. His initial head CT scan is shown above and left (figures 1.1 - 1.3), confirming acute obstructive hydrocephalus.

Figure 1.1

Figure 1.2

Figure 1.3

He was taken to the operating room and an emergency ventriculostomy was placed. Postoperatively, she recovered to GCS 15, and after initial problems with upward gaze, was neurologically intact. An MRI scan of the brain was performed which confirmed aqueduct stenosis with hydrocephalus, probably secondary to webbing of the aqueduct. The floor of the 3rd ventricle was noted to be bulging downwards, with a normal sized 4th ventricle (see figures 1.4 - 1.5 below):

Figure 1.4

Figure 1.5

3 days after EVD insertion, he was transferred to Dalcross Private Hospital to undergo endoscopic 3rd ventriculostomy.

Procedure

After being placed under general anaesthesia, the ventricular drain was removed, and using frameless stereotaxy a peel away sheath and rigid 30° endoscope was placed into the right lateral ventricle.

The procedure is shown pictorially below:

Figure 1.6	Figure 1.7
Figure 1.6 (above): View of from the right lateral ventricle of the foramen of Monro with the choroid plexus visualized to the left.	Figure 1.7 (above): Once the 3rd ventricle was entered, the attenuated floor of the 3rd ventricle was visualized. The mamillary bodies are shown posteriorly, and the infundibulum anteriorly. A small artery connecting the massa intermedia had to be negotiated. Note that the blunt forceps are approaching the floor of the 3rd ventricle between these structures.

Figure 1.8	Figure 1.9
Figure 1.8 (above): The forceps are now passing through the floor of the 3rd ventricle and by opening the forceps, the opening is enlarged.	Figure 1.9 (above): The initial 3rd ventriculostomy.

Figure 1.10	Figure 1.11
Figure 1.10 (above): A 4F Fogarty balloon, is now inserted through the ventriculostomy.	Figure 1.11 (above): The balloon is inflated with 4 ml of saline and the ventriculostomy is enlarged.

Figure 1.12	Figure 1.13
Figure 1.12 (above): The final ventriculostomy.	Figure 1.13 (above): The 6 mm endoscope is now passed through the ventriculostomy to enlarge the stoma. The clivus is visible anteriorly and the broad expanse of the basilar artery is noted in the foreground. In this case the basal cisterns are widely patent.

Figure 1.14
Figure 1.14 (above): The final ventriculostomy after dilatation with the ventriculoscope.

Postoperatively, the patient did very well. He remained neurologically intact and the postop imaging confirmed reduction in the hydrocephalus, with a reconstructed CT showing the defect in the floor of the 3rd ventricle (figures 1.15 - 1.17 below):

Figure 1.15	Figure 1.16
Figure 1.17

At 3 months post-surgery, he remained asymptomatic. His repeat MRI with flow studies confirmed patency of the ventriculostomy (see figure 1.18-20 below):

Figure 1.18

Figure 1.19

Figure 1.20

He was well at last follow up.

Comment

Aqueduct stenosis is the commonest cause of obstructive hydrocephalus in adults. In the past, this was managed with ventriculoperitoneal shunting, which condemned the patient to a lifelong risk of infection and shunt blockage. The risks of further surgery in a shunt dependent patient are not low, with blockage and infection being the primary indications. There have been several reports on endoscopic 3rd ventriculostomy success rates. The reported success rates are usually in the range of 60 to 80%. It is higher in patients with aqueduct stenosis and adult onset hydrocephalus. Intracerebral infection is a significant independent risk factor for failure, whether it occurred in the past or during follow-up monitoring. Intracerebral infection can cause meningeal adhesions in the subarachnoid space, which can result in communicating hydrocephalus. Communicating hydrocephalus may present concomitant with obstructive hydrocephalus or may develop later, secondary to infection. Patients with previous shunt infections are considered controversial as candidates for endoscopic 3rd ventriculostomy. The probability of success (22.2% at 2.0 yr) is disappointingly low. More than 3 shunt revisions is itself a risk factor by itself, in the absence of infection.

In select patients, this minimally invasive procedure may avoid shunting and is associated with a >90% initial success rate.

Case 2- Lumbar Endoscopy

History

This 55 year old man was referred to the surgeons at Dalcross Private Hospital and after having had 3 previous lumbar operations. The initial operation had been performed elsewhere for lumbar disc disease, at which time he suffered an inadvertent dural breach. Postoperatively, she developed a lumbar pseudomeningocoele and had 2 attempts elsewhere to try and close the leak. Their was currently no leakage of CSF from the wound. Unfortunately, he continued to have symptoms, and had postural symptoms of worsening back pain and pressure in the standing posture, relieved by lying down. His most recent preoperative MRI scan on referral is shown below (figure 2.1-2.2):

Figure 2.1

Figure 2.2

The MRI suggested a multiloculated CSF collection in the subfascial region of the lumbar wound. In view of the fact that he had had 2 previous attempts to repair the pseudomeningocoele, it was felt that a further open procedure would not be of great benefit. Symptomatically, the patient had a one-way valve effect with fluid draining from his thecal sac into his pseudomeningocoele, that was thought to be giving him the majority of his symptoms.

Technique

Figure 2.3

The patient was brought to the operating room and general anaesthesia was obtained. He was place in a prone position on the Andrews operating table. A rigid 6 mm 30° endoscope was then navigated into the pseudomeningocoele through a 1 cm paramedian lumbar incision. The pinhole connection between the dura and surrounding tissues was identified and this was enlarged with forceps and a 4F 5 ml Fogarty balloon (see figures 2.3-2.4 left)

Figure 2.4

Figure 2.3 and 2.4 (left): The 1 mm connection between the pseudomeningocoele and the thecal sac is identified. A magnified view is shown to the right. Neural structures are visible inside the dura. The procedure was uncomplicated and an on-table myelogram confirmed good retrograde flow between the pseudomeningocoele and the thecal sac (see figure 2.5).

Figure 2.5

Figure 2.5 (left): Post-fenestration myelogram confirming good retrograde flow of contrast material.

Postoperatively, the patients recovery was unremarkable and he was well at last followup from her preoperative symptoms.

Comment

Cerebrospinal fluid leakage can complicated up to 10% of spinal surgical cases. Typically these are primary repaired and require no further intervention. Rarely, the leaks persist and patients may present with persistent CSF leakage from the wound, a subcutaneous swelling or a contained but symptomatic swelling. The initial treatment in typically aspiration and lumbar drainage or re-exploration. An epidural blood patch may also help. Occasionally this is unsuccessful. In the case, with 2 previous re-explorations, it was felt a minimally invasive procedure would avoid the pain and risks of another open procedure. Coupled with this, the internal architecture of the pseudomeningocoele was not disturbed, which allowed for easier identification of the flap valve.

Case 3- Multiple Key-hole Craniotomies for Tumour

History

This 56 year old man presented initially with a dense L. hemiparesis and headaches and vomiting. He had a past medical history of renal cell carcinoma which was resected by a partial nephrectomy 5 years previously. Initial MRI scanning confirmed 2 metastatic lesions, one in the right inferior parietal lobe, and the 2nd in a parasagittal position in the right frontoparietal region (see figures 3.1-3.4).

Figure 3.1	Figure 3.2
Figure 3.1	Figure 3.1

Figure 3.1-3.4 (above): Initial MRI scans showing 2 right hemisphere lesions consistent with metastases.

Technique

Using frameless stereotactic localization, the 2 lesions were removed through a single linear skin incision, via 2 flap free flap craniotomies. Through the use of precise stereotactic localization small craniotomies effected the resection. The postoperative CT scans are shown in figures 3.5-3.6.

Figure 3.5

Figure 3.6

Figure 3.5-3.6 (above): Initial postoperative CT brain scan showing satisfactory resection of both right hemisphere lesions. Some blood is evident in the bed of the resection of the larger metastasis.

Postoperatively, the patient made a superb recovery with recovery of motor function. He was discharged 10 days postoperatively and underwent whole brain radiotherapy. Progress MRI scanning of the brain at 3 months after surgery showed no evidence of recurrent or residual disease (see figure 3.7).

Figure 3.7

Figure 3.7 (left): MRI brain scan performed 3 months after initial surgery showing no evidence of recurrent disease.

Six months after initial surgery, the patient experienced severe headache, nausea and vomiting. CT scanning and MRI scanning of the brain confirmed that the large right frontoparietal lesion had recurred, and also that there was a new left frontal lesion with marked mass effect and a smaller right temporal lesion (see figures 3.8-3.10 below):

Figure 3.8	Figure 3.9
Figure 3.10

Figures 3.8-3.10 (above): CT scan (left) and MRI scans (middle and right) performed 6 months after initial surgery. The right posterior frontoparietal lesion has recurred with the presence of a new left frontal and right temporal lesion. Marked oedema surrounds the lesions.

Again it was elected that these lesions be resected, primarily as there was marked mass effected, and also because the patient was otherwise well. Frameless stereotactic CT guidance was again used, and via linear incisions and small craniotomies, the recurrent right frontoparietal and left frontal lesions were excised. The right temporal lesion was not resected. Postoperatively he was well. CT scanning performed 1 month after the 2nd surgery showed good resolution of the cerebral oedema and mass effect, and the remaining right temporal lesion was satisfactorily resected using frameless stereotaxy, via a keyhole approach (see figure 3.11 below):

Figure 3.7

Figure 3.11 (left): Final CT scan performed after resection of the right temporoparietal and left frontal lesions. The mass effect has been greatly reduced and only the right temporal lesion remains, which was subsequently resected.

Comment
This patient is an unusual case of a radioresistant tumour that recurred in a healthy patient in whom a total of 5 lesions were resected over a 12 month period. The patient is still alive and well. In this case, keyhole craniotomies were able to be performed through limited incisions which facilitated the removal of multiple lesions at single sittings. Not all patients with cancer in the brain are amenable to this technique. The decision-making is complex, and is done in consultation with the radiation oncologist and the clinical oncologist. The technologies available today, however, do allow for the safe application of techniques that were not available a mere decade ago.

Summary

Minimally-invasive cranial and spinal surgery is an exciting area of medicine which is rapidly undergoing technological advancement and refinement. Surgeons now have the ability to perform surgeries in a fashion not possible before.

The surgeons at Dalcross Private Hospital are skilled in the techniques discussed in the three example cases. Referrals can be made via your local doctor.