ATLANTOAXIAL SUBLUXATION MICROSURGERY
n July, Shannon G. and her family brought home two Yorkie puppies, Benny and his sister, Pippa. After having Benny groomed, they noticed Benny started to wobble. His condition worsened over the next few days to the point where Benny fell and couldn’t get up.
“We took him to our regular veterinarian who put Benny on steroids and antibiotics, but when we tried to wean him off the steroids, he got worse,” Shannon related recently. “On our third visit to the vet, he took an x-ray and saw a problem with the axial cervical spine. He then referred us toVNoC. After examining Benny, the neurologist explained that Benny was missing a bone that connects the cervical and axial spine. We could have gone with a neck brace since the neurologist said Benny could still be growing, but we realized that that was only a stopgap measure. After having lost two Yorkies last April, we wanted to do whatever we could to make Benny better. So we decided to do the surgery right away.”
FROM THE CASE FILE: THE NEUROLOGICAL EXAM
Subjective – Presenting Complaint and History: Losing balance: Benny presents as a 22-week-old male Yorkshire Terrier with ataxia in all four limbs, knuckling on the L front limb and pain in his neck. The Gs adopted Benny in late July and report that he has been perfectly healthy and active. He was taken in to be groomed mid-August and shortly after became ataxic. The Gs also report that he has been very hesitant to jump up or play with the other dog in the house. Benny was seen at the referring veterinarian on 8/22 where he was given a steroid and sent home. He improved initially but then started to “high-step”, was crying out when picked up and was painful upon palpation of his neck. On 9/4 the referring veterinarian obtained cervical radiographs where an instability was seen at C1-C2. Benny was sent home on Clavamox 0.3 mL BID x 14 days and Prednisone 0.75 mg BID which he initially improved on. He is now on the EOD Pred dose and is declining again. Mrs. G has been restricting his activity and keeping him from playing with the other dog. Benny has been eating, drinking, urinating and defecating normally and will be taking his last dose of Prednisone today.
Objective – Exam and Diagnostic Findings: We performed a complete Neurological examination and assessment including evaluating the mental status, posture, locomotion, postural reactions, spinal reflexes, complete cranial nerve examination, epaxial palpation and pain perception. Results of the identified abnormalities and our specific recommendations based on the exam. Please note that many of the normal findings are not listed.
Bladder – urinary function: Exam Normal. Owner reports normal urinary function, active and purposeful urination with normal stream of urine.
Notes on observation: Exam Normal. Normal mental status, posture, locomotion and gait.
Mental status: Quiet Abnormal – quiet states varies from one pet to the other, it is very nonspecific – many animals that are sick will be quiet.
Locomotion and gait: Exam Abnormal. Tetraparesis with spinal ataxia, worse in the thoracic limbs.
Knuckling or hopping in left thoracic limb: Delayed response Abnormal
Knuckling or hopping in right thoracic limb: Delayed response Abnormal
Wheelbarrow: Slow – symmetrical Abnormal
Tactile placing (thoracic limbs): Slow or absent in left limb Abnormal
Tactile placing (thoracic limbs): Slow or absent in right limb Abnormal
Notes on spinal reflexes:: Exam Normal Segmental spinal reflexes and withdrawal are all normal.
Notes on cranial nerve examination: Exam Normal. Cranial nerves examined found to be normal.
Palpation of cervical, thoracic, lumbar and sacral spine: Exam Normal – normal on palpation of c-spine as well as balance of spine.
Cutaneous trunci evaluation: Exam Normal. Normal cutaneous trunci reflex bilaterally.
Perception of superficial pain: Exam Normal. Normal response to superficial pain stimulation. Deep pain assessment is not necessary.
Notes on palpation, manipulation and pain perception: Exam Abnormal. Episodically painful at home. During radiographic exam, he vocalized spontaneously.
Assessment and Diagnosis: Atlanto-axial luxation (AA luxation or subluxation): Benny’s plain radiographs are consistent with an atlantoaxial subluxation. The ventrodorsal projection suggests the absence of an odontoid process (dens) as well. This is a congenital anomaly and not caused by trauma even though a minor trauma may have caused him to progress. An MRI might reveal another problem (i.e. hydrocephalus, Chiari-like malformation, etc.), however it would be very unlikely that we would treat a different condition. A radiograph taken today revealed that his growth plates are not completely closed, however I am recommending surgical stabilization sooner rather than later.
THE SURGERY
The atlantoaxial subluxation surgery was performed on Benny. The surgery involves placing 1.5 or 2.0 mm titanium screws (of various lengths) into the first two cervical vertebrae and placing a medical-grade cement across the screws while reducing the joint. VNoC’s operating microscope plays a crucial role in this surgery as there is very little room for error because the bones are less than 3 mm thick.
THE RESULTS
Six weeks after surgery, Shannon reported that Benny was doing well. “The surgery took 5 or 6 hours, and Benny was at VNoC for a total of three days. When he came first came home, we had to keep him crated. Initially he couldn’t lift his leg to pee, but now he can—and he’s doing great!
Because Benny’s condition was congenital, Shannon had his sister Pippa x-rayed, as well. “She has the same condition, but so far has shown no signs of the problem. It’s a waiting game; it could turn up later.”
Shannon and her family are grateful for the care Benny received. “Our animals are like family. Seeing Benny back to his old self has made it all worthwhile!”
Update: Three and a half months after Benny’s surgery, Shannon wrote:
I wanted to email you a short video of our sweet Benny, and of course Pippa, his sister who will not be ignored!!
Benny is doing amazing, and very playful!! He has put on some weight, and looking/acting happy & healthy!
I just wanted to say how much we appreciate your hard work and dedication!! We were always greeted with warm welcomes each visit during our dramatic turn of events!! Which made our experience stress free and comfortable for Benny and ourselves!
You and your staff were so caring, and did an awesome job of making Benny feel at home during his stay pre and post surgery.
Your follow-up phone calls and emails on his progress let us know how much you care about each individual patient that steps into your lives and facility.
As you can see Pippa is doing fine at this point and time. Hopefully things will continue on in this matter..
Thanks again for everything you did for our precious Benny!!
Much thanks & Happy holidays!!
Shannon, Murray, Rowan, Benny & Pippa