Have finally transcribed selected speaker notes verbatim. Complete speaker notes consist of three and a half typed pages. I'll follow with some of my notes from the session. Then I'll do the same for Dr. Shores' session. Glad I'm a good typist!
Pat
Selected verbatim text from Dr. Dewey’s speaker notes follows. I’ll put parentheses around my paraphrasing of his notes within the body. Multiple periods (…….) indicate that I have omitted some text. I have attempted to report the most important points while not violating copyright. When he uses ( ) I have substituted commas in order that anything in parentheses is my paraphrasing.
“Although only recently described in dogs, this is a very common neurologic disorder in this species…..almost exclusive to small breed dogs….with the CKCS being the most over-represented. The problem in the CKCS breed can be aptly described as a genetic crisis with an estimate of up to 95% of the population having some form of the disorder.”
“There is recent evidence that CM involves a malformation of the entire skull with the intracranial volume being too small to accommodate the intracranial contents. The vast majority of dogs with CM have SM, usually in the cervical spinal cord…..progressive alterations in pressure dynamics between the intracranial and spinal compartments are believed to be responsible for the development of clinical signs of CM/SM.”
“The intramedullary pulse pressure theory is currently the most accepted explanation for the formation of SM cavities in CM/SM…..(then he explains “Venturi effect” with distension, cavity formation, and filling of syrinx with “extracellular fluid” and the “suction effect.”)
“The typical age range at presentation appears to have changed over time, with many dogs developing clinical signs within the first year of life……most dogs present by the time they are 4 years old….dogs that are presented at less than 2 often have more severe clinical signs than older dogs….we have seen an increasing number of younger patients less than one year of age….whether this trend reflects an increasing severity of the disorder with subsequent generations, increased awareness of the veterinary community and hence earlier diagnosis, or a combination of these two factors is unknown.”
(He goes on to describe symptoms – nothing that we haven’t heard before.) “It is important to realize that, especially in the CKCS breed, other conditions may account for some of the clinical signs.” (Goes on to describe PSOM, idiopathic epilepsy, congenital deafness, disk extrusion, inflammatory brain disease – all in CKCS.) “….it may be difficult to discern if the CM/SM is the main problem, contributory, or an incidental finding.”
(He goes on to describe MRI and MRI findings. Nothing new.) “Recently, the width of cervical syrinxes as measured on axial MR images was positively correlated with presence of pain in CKCS dogs with CM/SM.”
“Treatment of CM/SM can be divided into medical and surgical therapy.” (He then reports on human surgical treatment and success/failure rates.) “Medical therapy for dogs with CM/SM generally falls into three categories: analgesic drugs, drugs that decrease CSF production, and corticosteroid therapy.” (Talks about gabapentin and pregabalin….they are using pregabalin more now….it has a longer half-life…7 hrs versus 3-4 hrs and appears to be more potent….says he’s had success with tramadol…..talks about CSF reducing drugs – says all information is anecdotal….said during his talk when I asked that he doesn’t think CSF reducing drugs actually do anything….goes on to cover corticosteroids….says dose should be moved to every other day therapy within a month if at all possible….I certainly agree with that!)
“The preferred surgical procedure for treatment of CM/SM in dogs is FMD. However, surgical success in dogs appears to be less predictable than that reported for people. In one report, the success rate, resolved or improved, was 81.25%. Unfortunately, there was a 25% re-operative rate due to scar tissue formation in this study. This report also found an inverse relationship between the length of time clinical signs were present prior to surgical intervention and the extent of post-operative improvement. In another report, the ultimate surgical failure for FMD in CKCS dogs was near 50% with long-term, >1 year, follow-up. In most cases, clinical signs of pain are routinely relieved with surgery, but scratching activity tends to persist.” (Then he describes his titanium mesh cranioplasty.) “So far, the author and colleagues have operated over (sic) 100 dogs with this procedure. Although results are preliminary, the cranioplasty procedure appears to have substantially decreased the re-operation rate for this disorder in dogs. There is recent evidence that the malformation in CKCS dogs is not restricted to the caudal fossa, and that the disease may represent a relative volume deficiency of the entire intracranial compartment. If this is correct, part of the reason for surgical failure in these dogs may be due to inadequate decompression with a suboccipital approach.”
“There is little information regarding the prognosis for CM/SM in dogs. Most dogs with CM/SM will respond favorably to medical therapy, although in many cases this response is temporary. In one group of 10 CM/SM dogs treated medically, 5 dogs (50%) were euthanized within 2-3 years due to disease progression and diminished responsiveness to therapy. In another report, 5 of 14 dogs, 36%, with the disorder treated medically were eventually euthanized due to disease progression.” (note from Pat – these studies obviously have a TINY number of participants) “Although the surgical success rate is generally favorable for CM/SM in dogs in the short-term, the recurrence rate due to excessive post-operative scar tissue formation is unacceptably high. Hopefully, refinements in surgical technique, such as cranioplasty, will ameliorate this problem. In general, the overall prognosis for CM/SM in dogs is guarded to good for sustained improvement of clinical signs.”
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My personal notes from his session:
15 attendees, including myself.
40% of CM/SM dogs have cerebellar herniation.
He suspects CM/SM genes were in the longer-muzzled dogs used as foundation stock in CKCS.
He reported a sweet story about a dog that was going to be euthanized by owner that he took home. Didn’t tell what happened or how dog is now.
Says new theory is that entire skull is too small, not just the back of skull. Global squishing of the brain.
70-95% of CKCS are affected. 40% asymptomatic. Can be a devastating disorder.
Syrinx usually starts at C2.
Screening tools – BAER may be too sensitive. Working on thermography. “You have a Cavalier, you have CM.” We need a screening test that will tell if dog is symptomatic. “You have two cups of coffee before you do surgery….not one and not three.”
Old theory – Assume fluid CSF; water hammer/suck effect; perivascular space, piston, slosh.
New theory – Not true (that it’s CSF fluid); intramedulliary (sp?) pulse pressure; venturi effect, vascular, probably interstitial fluid, not CSF, goes through constriction at C-2, pull venturi, extra-cellular fluid. Less of a reason to use proton pump inhibitor or furosemide (I raised my hand and asked that question); don’t think they work very well anyway.
Described “Beezer Squeezer” (named after a grade school teacher he had) – asymptomatic dogs are not really asymptomatic because they will scream if you pinch the back of the neck hard and pinch the skull hard right above zygomatic arch. (Note from Pat – don’t try this at home. Dr. Shores said the same thing when I told him what Dr. Dewey said about this. Of course I rushed home and started smishing my two Cavaliers’ heads and necks but I had no idea exactly where or how hard to squeeze. My 8 year old Cavalier seemed to flinch, and I lost my nerve and stopped as I was afraid to know. My 1 year old looked at me like I was nuts which encouraged me to squeeze harder. No reaction. I probably should not be reporting this, but I am. Karlin can remove or not.)
Went on to discuss strabismus, scoliosis, torticolis, now seeing younger dogs. No thoracolumbar syrinx present without cervical syrinx. T2 weighted mid-saggital view, CT scan. Rule out concurrent brain disorders. Lyrica probably better than gabapentin. Half life 7 hrs versus 3-4 hours. ½ dose for cats (cats? Cats have CM/SM???? Edited to add that he was probably just saying that they also use these drugs for various disorders in cats) Medical therapy successful short term. 50% euthanized after two years. 36% euthanized after 1.7 yrs. 80% surgeries are successful; 25-50% relapse – scar tissue. Titanium mesh cranioplasty. Use titanium so that you can do future MRIs. Results – improvement similar. Stay in hospital longer. 7% re-operation rate; plate loosened, scar tissue. 80% improvement with some medication. Occasional secondary lesions. Shunting makes little sense. Wider decompression might not be crazy, now that we know it is a global skull problem.
Future direction – wider decompression, other concurrent malformation. Supratentorial (sp?) decompression in addition to FMD. (He mimed cutting out a hole in the top of the skull. Made the hair on my arms stand up in reaction to that plus FMD!!!) He uses glue – no staples, no sutures.
End of notes. Took two hours to transcribe this. Not sure if I’ll do Dr. Shores tonight.
Pat
Selected verbatim text from Dr. Dewey’s speaker notes follows. I’ll put parentheses around my paraphrasing of his notes within the body. Multiple periods (…….) indicate that I have omitted some text. I have attempted to report the most important points while not violating copyright. When he uses ( ) I have substituted commas in order that anything in parentheses is my paraphrasing.
“Although only recently described in dogs, this is a very common neurologic disorder in this species…..almost exclusive to small breed dogs….with the CKCS being the most over-represented. The problem in the CKCS breed can be aptly described as a genetic crisis with an estimate of up to 95% of the population having some form of the disorder.”
“There is recent evidence that CM involves a malformation of the entire skull with the intracranial volume being too small to accommodate the intracranial contents. The vast majority of dogs with CM have SM, usually in the cervical spinal cord…..progressive alterations in pressure dynamics between the intracranial and spinal compartments are believed to be responsible for the development of clinical signs of CM/SM.”
“The intramedullary pulse pressure theory is currently the most accepted explanation for the formation of SM cavities in CM/SM…..(then he explains “Venturi effect” with distension, cavity formation, and filling of syrinx with “extracellular fluid” and the “suction effect.”)
“The typical age range at presentation appears to have changed over time, with many dogs developing clinical signs within the first year of life……most dogs present by the time they are 4 years old….dogs that are presented at less than 2 often have more severe clinical signs than older dogs….we have seen an increasing number of younger patients less than one year of age….whether this trend reflects an increasing severity of the disorder with subsequent generations, increased awareness of the veterinary community and hence earlier diagnosis, or a combination of these two factors is unknown.”
(He goes on to describe symptoms – nothing that we haven’t heard before.) “It is important to realize that, especially in the CKCS breed, other conditions may account for some of the clinical signs.” (Goes on to describe PSOM, idiopathic epilepsy, congenital deafness, disk extrusion, inflammatory brain disease – all in CKCS.) “….it may be difficult to discern if the CM/SM is the main problem, contributory, or an incidental finding.”
(He goes on to describe MRI and MRI findings. Nothing new.) “Recently, the width of cervical syrinxes as measured on axial MR images was positively correlated with presence of pain in CKCS dogs with CM/SM.”
“Treatment of CM/SM can be divided into medical and surgical therapy.” (He then reports on human surgical treatment and success/failure rates.) “Medical therapy for dogs with CM/SM generally falls into three categories: analgesic drugs, drugs that decrease CSF production, and corticosteroid therapy.” (Talks about gabapentin and pregabalin….they are using pregabalin more now….it has a longer half-life…7 hrs versus 3-4 hrs and appears to be more potent….says he’s had success with tramadol…..talks about CSF reducing drugs – says all information is anecdotal….said during his talk when I asked that he doesn’t think CSF reducing drugs actually do anything….goes on to cover corticosteroids….says dose should be moved to every other day therapy within a month if at all possible….I certainly agree with that!)
“The preferred surgical procedure for treatment of CM/SM in dogs is FMD. However, surgical success in dogs appears to be less predictable than that reported for people. In one report, the success rate, resolved or improved, was 81.25%. Unfortunately, there was a 25% re-operative rate due to scar tissue formation in this study. This report also found an inverse relationship between the length of time clinical signs were present prior to surgical intervention and the extent of post-operative improvement. In another report, the ultimate surgical failure for FMD in CKCS dogs was near 50% with long-term, >1 year, follow-up. In most cases, clinical signs of pain are routinely relieved with surgery, but scratching activity tends to persist.” (Then he describes his titanium mesh cranioplasty.) “So far, the author and colleagues have operated over (sic) 100 dogs with this procedure. Although results are preliminary, the cranioplasty procedure appears to have substantially decreased the re-operation rate for this disorder in dogs. There is recent evidence that the malformation in CKCS dogs is not restricted to the caudal fossa, and that the disease may represent a relative volume deficiency of the entire intracranial compartment. If this is correct, part of the reason for surgical failure in these dogs may be due to inadequate decompression with a suboccipital approach.”
“There is little information regarding the prognosis for CM/SM in dogs. Most dogs with CM/SM will respond favorably to medical therapy, although in many cases this response is temporary. In one group of 10 CM/SM dogs treated medically, 5 dogs (50%) were euthanized within 2-3 years due to disease progression and diminished responsiveness to therapy. In another report, 5 of 14 dogs, 36%, with the disorder treated medically were eventually euthanized due to disease progression.” (note from Pat – these studies obviously have a TINY number of participants) “Although the surgical success rate is generally favorable for CM/SM in dogs in the short-term, the recurrence rate due to excessive post-operative scar tissue formation is unacceptably high. Hopefully, refinements in surgical technique, such as cranioplasty, will ameliorate this problem. In general, the overall prognosis for CM/SM in dogs is guarded to good for sustained improvement of clinical signs.”
------------------------------------------------------
My personal notes from his session:
15 attendees, including myself.
40% of CM/SM dogs have cerebellar herniation.
He suspects CM/SM genes were in the longer-muzzled dogs used as foundation stock in CKCS.
He reported a sweet story about a dog that was going to be euthanized by owner that he took home. Didn’t tell what happened or how dog is now.
Says new theory is that entire skull is too small, not just the back of skull. Global squishing of the brain.
70-95% of CKCS are affected. 40% asymptomatic. Can be a devastating disorder.
Syrinx usually starts at C2.
Screening tools – BAER may be too sensitive. Working on thermography. “You have a Cavalier, you have CM.” We need a screening test that will tell if dog is symptomatic. “You have two cups of coffee before you do surgery….not one and not three.”
Old theory – Assume fluid CSF; water hammer/suck effect; perivascular space, piston, slosh.
New theory – Not true (that it’s CSF fluid); intramedulliary (sp?) pulse pressure; venturi effect, vascular, probably interstitial fluid, not CSF, goes through constriction at C-2, pull venturi, extra-cellular fluid. Less of a reason to use proton pump inhibitor or furosemide (I raised my hand and asked that question); don’t think they work very well anyway.
Described “Beezer Squeezer” (named after a grade school teacher he had) – asymptomatic dogs are not really asymptomatic because they will scream if you pinch the back of the neck hard and pinch the skull hard right above zygomatic arch. (Note from Pat – don’t try this at home. Dr. Shores said the same thing when I told him what Dr. Dewey said about this. Of course I rushed home and started smishing my two Cavaliers’ heads and necks but I had no idea exactly where or how hard to squeeze. My 8 year old Cavalier seemed to flinch, and I lost my nerve and stopped as I was afraid to know. My 1 year old looked at me like I was nuts which encouraged me to squeeze harder. No reaction. I probably should not be reporting this, but I am. Karlin can remove or not.)
Went on to discuss strabismus, scoliosis, torticolis, now seeing younger dogs. No thoracolumbar syrinx present without cervical syrinx. T2 weighted mid-saggital view, CT scan. Rule out concurrent brain disorders. Lyrica probably better than gabapentin. Half life 7 hrs versus 3-4 hours. ½ dose for cats (cats? Cats have CM/SM???? Edited to add that he was probably just saying that they also use these drugs for various disorders in cats) Medical therapy successful short term. 50% euthanized after two years. 36% euthanized after 1.7 yrs. 80% surgeries are successful; 25-50% relapse – scar tissue. Titanium mesh cranioplasty. Use titanium so that you can do future MRIs. Results – improvement similar. Stay in hospital longer. 7% re-operation rate; plate loosened, scar tissue. 80% improvement with some medication. Occasional secondary lesions. Shunting makes little sense. Wider decompression might not be crazy, now that we know it is a global skull problem.
Future direction – wider decompression, other concurrent malformation. Supratentorial (sp?) decompression in addition to FMD. (He mimed cutting out a hole in the top of the skull. Made the hair on my arms stand up in reaction to that plus FMD!!!) He uses glue – no staples, no sutures.
End of notes. Took two hours to transcribe this. Not sure if I’ll do Dr. Shores tonight.
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