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IML - Integrated Medical Learning Audience Questions and Answers |
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| SPINE Audience Question/Answers |
At the Tuesday IML Session, attendees were given the opportunity to send questions to the experts via handheld devices and personal computers. The 2007 Annual Meeting moderators and experts answer your questions which were not addressed in the limited time during the actual General Scientific Session.
References Cited by Experts (Selected)
- Schwab F, Lafage V, Farcy JP, Bridwell K, Ondra SL et al. Spine 2007
- Labelle H, Roussouly P, O’Brien M, et al: SPINE, Vol. 30, Number 6S, pp S27–S34, 2005
- Labelle H, Roussouly P, Berthonnaud E, et al. Spondylolisthesis, Pelvic Incidence and Spinopelvic balance: A correlation study. Spine 29, 2004
- Putzier et al. spine 30 2005
- Stoll Eur Spine J 11 2002
- Weinstein JN, Tosteson TD, Lurie JD et al. Surgical vs nonoperative treatment of lumbar disk herniation: The spine patient outcomes research trial (SPORT) A randomized trial JAMA 296 2006
- McCormick PC. The spine patient outcomes research trial results for lumbar disc herniation: a critical review. J Neurosurg Spine. 6:513, 2007
- Surgical versus nonsurgical treatment for degenerative spondylolisthesis NEJM 356:22 2257. 2007
| Q: | Do you always check for abnormal motion before you fuse? |
| A: | No, abnormal movement is one of the indications for fusion. For example, if significant reduction is planned or iatrogenic instability is a concern a fusion could be planned without checking for abnormal movement pre-operatively. |
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| Q: | Is there a difference in the incidence of adjacent level instability after posterior instrumented fusion if the Arthrodesis is interbody or posterolateral? |
| A: | Our understanding is that adjacent level instability after posterior approaches is due to injury of the facet joint immediately above the superior instrumentation. There is no reason to expect a different incidence with these two approaches. |
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| Q: | Is there a difference in the incidence of adjacent level instability after posterior instrumented fusion if it is done open or minimally invasively? |
| A: | Our understanding is that adjacent level instability after posterior approaches is due to injury of the facet joint immediately above the superior instrumentation. There is no reason to expect a different incidence with these two approaches. |
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| Q: | Isn’t using BMP for smokers putting a Band-Aid on a larger problem? |
| A: | Nicotine addiction is a systemic disease. It is worth noting that council from a spine surgeon as been shown to be more effective in achieving cessation then council from other practitioners. In addition, Arthrodesis is an explicit goal of the procedure which is furthered by the use of BMP. |
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| Q: | Comment on the aspect of financial bias. |
| A: | Since surgery is a fee for service endeavor there is a financial incentive to operate on patients. This incentive applies to the full spectrum of neurosurgery and is not unique to cases involving instrumentation. One of the obligations of being a professional is not allowing that incentive to impact on your clinical decision making. |
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| Q: | If we know that BMP increases fusion rates should it be used on every case? |
| A: | In many cases the fusion rates are so high that the additional efficacy is minimal while the additional cost is high. |
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| Q: | Why optimize fusion rates if successful fusion does not predict outcome? |
| A: | The explicit goal of arthrodesis is fusion, and therefore, every effort should be made to optimize it. The fact that a correlation with outcome has not been demonstrated suggests either that the research is inadequate or that some other factor as yet to be determined is at play. |
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| Q: | What references are available to assess fusion stability? |
| A: | Lumbar fusion guidelines (JNS 2005). |
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| Q: | Have you noticed that patients do not want to wait? |
| A: | Yes. It is our duty to guide patient towards the best medical decision even it may not be what they would have initially chosen. |
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| TUMOR Audience Question/Answers |
At the Monday IML Session, attendees were given the opportunity to send questions to the experts via handheld devices and personal computers. The 2007 Annual Meeting moderators and experts answer your questions which were not addressed in the limited time during the actual General Scientific Session.
| Q: | What is the most appropriate timing for WBRT after surgery? |
| A: | As reasonably soon as possible, ideally, once the incision has healed adequately. |
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| Q: | What is the cost-benefit relationship for SRS given the relatively small improvement in survival seen in randomized studies? |
| A: | Cost-benefit studies show this procedure to be beneficial, with significantly improved QALYs. |
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| Q: | At which point does treatment of multiple mets with SRS result in WBRT-like exposure of the distant brain? |
| A: | This is not a simple question, because this is a function of both the number of brain metastases and the size; even with up to 10 small lesions, less brain receives WBRT type doses; however, more brain receives higher dose-gradients, and hence the mean brain dose might in fact be higher. |
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| Q: | What is the appropriate timing for surveillance imaging once a brain metastasis has been treated? |
| A: | This has not been adequately studied; common practice is every 2 to 3 months. |
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| Q: | What impact does tumor histology have on treatment response and outcome? |
| A: | I am assuming that this is relative to SRS; the data suggest that radiosensitive histologies such as small cell regress the fastest, and melanoma, sarcoma and renal cell regress slowly; however, in these so called radioresistant tumors, delayed responses are not uncommon. |
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| Q: | How do we open trials at our hospital? |
| A: | The NCI.gov website is a very good resource; ASCO has a resource on its website as well; the best way is to get a CRO (clinical trial data manager) and have them visit a facility which has trials in place so you can decide what resources you need. |
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| Q: | To what depth should resection cavity radiosurgery be dosed? |
| A: | This question does not have a well-known answer; it really depends on how far out you believe microscopic disease extends. |
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| Q: | What are the neurocognitive effects of multiple met treatment with SRS? |
| A: | Not well studied. With chemo? “Chemo-brain” is now a well recognized entity and there are clearly neurocognitive deficits induced by chemotherapy, even in patients without brain metastases. |
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| VASCULAR Audience Question/Answers |
At the Wednesday IML Session, attendees were given the opportunity to send questions to the experts via handheld devices and personal computers. The 2007 Annual Meeting moderators and experts answer your questions which were not addressed in the limited time during the actual General Scientific Session.
| Q: | Do you routinely screen relatives for unruptured aneurysms? |
| A: | In general, we do not screen relatives of patients with cerebral aneurysms unless there is another affected first degree relative or at least two less closely related affected family members. Although relatives of those without other affected members are more likely to be affected than non-relatives with no family history of aneurysm, the existence of a single affected member does not make screening cost effective and may result in unnecessary psychological burden as it remains unclear how often one should screen patients and how to best manage many of the small lesions ultimately discovered on non-invasive imaging studies. |
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| Q: | Is routine intraoperative angiography necessary and how does it compare with microdoppler microscopic video angiography? |
| A: | Although no randomized trials have been conducted to definitively weight the risks and benefits of intraoperative angiography versus either of these less invasive interrogations or no interrogation at all, most high volume centers are employing this technique with greater regularity and have reported favorable impressions. It is the opinion of this panel that, when available, intraoperative angiography is generally helpful and should be considered in most cases and that it gives far more information than either of the competing technologies. |
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| Q: | Should community surgeons or community radiologists be treating aneurysms, without the full complement of support available to those practicing in high volume referral centers; what is the liability associated with treatment in these community settings where joint decision making is not always possible and how should transfer decisions be made? |
| A: | In treating cerebral aneurysms, both ruptured and unruptured, optimal treatment often and sometimes
unpredictably requires a large team of highly expert physicians and ancillary staff with a wide range of skills. Except in the case of a patient herniating
from associated hematoma it is usually in the patient’s best interest to transfer the patient as soon as possible to a high quality high volume center
possessing such a team that is in the habit of providing care that is patient centered and specific. Not all of the referral centers meeting these
criteria openly accept patients regardless of insurance status, nevertheless, many do and every effort should be made to identify those that do in
advance of an emergency. Having said this, there is no class I evidence that a policy of early transfer to high volume centers actually improves
outcome, and given the increased rebleeding that might be expected with such a policy, additional data is needed to render this standard of care. |
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| Q: | Is a preoperative angiogram always necessary if a preoperative CTA has already been done and if you don't do intra-op angio, when do you get a post-op angio and after initial proof of aneurysm obliteration when do you get delayed follow-up studies in both coiled and clipped patients? |
| A: | If a high quality CTA shows all the pertinent anatomical issues of concern to the surgeon it is not
necessary to obtain a preoperative angiogram, but a CTA may sometimes miss small lesions that one is not looking for which might be treated during
the same operation and angiography is generally helpful in determining whether a lesion is truly amenable to GDC. While there is no uniform answer
regarding postoperative imaging it is generally advisable to perform at least one catheter angiogram post clipping usually before discharge from the
hospital if not intraoperatively and usually two post-coiling, one in the first 6 months and another within the first two years. In the case of residual
aneurysm post either clipping or coiling serial imaging is also generally felt to be a good idea. This is usually done noninvasively with either gadolinium
enhanced MRA or CTA. The former tends to produce better images after coiling and the latter tends to provide better information after clipping but it
depends on the imaging center. Both techniques have risks and unenhanced MRA may be best in certain situations such as those who are pregnant. If
the aneurysm has been completely treated by either technique and recurrence is thought to be unlikely, non-invasive imaging at greater intervals may
still be considered as late recurrences have been seen both after clipping and coiling and there is a definite incidence of de novo aneurysm formation.
The inability of the patient to control such environmental stressors such as tobacco use may play a role in long range screening decisions. |
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| Q: | Is dome packing a ruptured aneurysm that is not ideal for either clipping or coiling a valid therapeutic concept? What are the pitfalls of clipping after "protective" incomplete coiling in the setting of SAH? |
| A: | At least in some instances dome coiling appears to offer some degree of protection although this has never been adequately studied. If this is performed fibrinolytics should probably not be used and early repeat angiography to document stability should be performed. When the patient has stabilized either device-assisted completion of the coiling should be performed or clipping attempted. When the latter is undertaken care should be taken to avoid clipping the coil mass and to releasing the dome as much as possible to avoid shearing the lesion at the virgin tissue coil interface. |
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| Q: | Do expert microsurgeons believe that coiling is definitive therapy for a cerebral aneurysm? |
| A: | In some cases it clearly appears to be but the exact natural history of completely coiled and incompletely coiled lesions at various locations in certain patient populations requires increased follow-up to determine in which cases coiling is likely to be definitive. At present if an aneurysm with favorable anatomy is completely coiled and remains totally obliterated several years post-op it is likely to represent a definitive cure. |
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| Q: | If an aneurysm is symptomatic from mass effect, can coiling relieve these symptoms or is clipping necessary and if so must the dome be acutely removed or decompressed? |
| A: | There are several reports of third nerve palsies and other compression syndromes resolving with coiling alone but there are reports of palsies worsening as well. When all things are equal, most teams believe that surgical clipping in these instances accompanied by immediate decompression is preferable, but while needling the dome is generally low risk actually removing the dome may be contraindicated if this requires excessive manipulation or extensive dissection of the nerve dome interface. |
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| Q: | What is the risk of rupture during coiling of small aneurysms and what is more important, neck to dome or neck to parent vessel artery? |
| A: | While there is no exact answer to either question it is clear to most endovascular surgeons that very small aneurysms (< 4mm) do present a greater risk for intraoperative rupture and both neck to dome and neck to parent artery ratios are important in treating aneurysms of all sizes, shape and location. In some instances, one ratio may be more important than the other but the reverse may be true in other instances. |
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| Q: | How quickly do you treat aneurysms of poor grade SAH? |
| A: | In general, if one is going to treat a patient with poor grade SAH optimally, this requires early repair of the aneurysm by whatever means necessary. While there is no class I data to support this contention, multiple single-center series support this contention. |
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December 12, 2007
2008 CNS Abstract Center Opens |
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September 20 - 25, 2008
2008 CNS Annual Meeting
Orlando, Florida |
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