Tracking Syrinx Improvement After Surgery

November 30, 2008 -- Outcome studies, where a surgeon reports on how a series of patients did after surgery, are common in the Chiari literature. Although they tend to suffer from scientific limitations (such as lack of specific outcome measures) which make them difficult to draw conclusions from, over time the types of data that is reported in these studies has improved and they do provide an interesting snapshot into what patients facing surgery might expect.

A group from Johns Hopkins (Attanello et al.) recently published just such an outcome study in the June, 2008 issue of the journal, Neurosurgery. In it, they reported the surgical results of 49 children with Chiari and syringomyelia, paying particular attention to the syrinx related symptoms. The researchers used imaging, operative records, and clinical records to create a database containing demographic information, symptoms, neurological deficits, imaging characteristics, and surgical records. The syrinx specific symptoms included:

  • Parasthesia

  • Dysesthesia

  • Weakness

  • Incontinence

  • Gait Instability

  • Scoliosis

Naturally, all the children received pre-operative MRIs. They also received an MRI 3 months after surgery, and an additional one 12-18 months after surgery. They were followed for an average of 41 months. For purposes of analysis, a reduction in size of a syrinx on MRI by 20% or more was considered a decrease. Anything less than 20% was considered to be no change.

The average age of the children at the time of surgery was 11 years. Although they all had syrinxes, 20% were found to have no symptoms directly associated with syringomyelia (they did of course have Chiari related symptoms bad enough to warrant surgery). Nearly half the children suffered from numbness and tingling (parasthesia), and more than a quarter from painful sensations (dysesthesia, Figure 1). In addition, 41% had some degree of scoliosis. Ninety-four percent of the children had a syrinx involving the cervical region, and in about half the thoracic region was affected. The average syrinx size was more than six vertebral segments, and in six children the syrinx ran the length of the cord.

Clinically, 54% of the children experienced an improvement of their symptoms 4 months after surgery (Figure 3). This had increased to 61% by one year. Only one child experienced an improvement after the one year mark. In looking at specific symptoms, the researchers found that motor related symptoms were more likely to improve than the numbness/tingling (Figure 2).

Interestingly, improvement on MRIs came much later than the reported symptom improvement. Specifically, 55% of the cases showed a decrease in the syrinx, but it took 14 months after surgery for this to occur. Within this group, 6 children had their syrinx resolve completely and 21 had it decrease in size. One child's syrinx actually grew in size and that child underwent a reoperation. The 55% reduction rate is lower than some other published literature, but the authors point out that if they changed their criteria to any reduction in size (as opposed to at least 20%), then the number jumps to 73%, which is in line with other reports. The authors also point out that the children with persistent symptoms were very likely to have progressive scoliosis, even after decompression surgery.

It is difficult to say what can be drawn from this study, but it is interesting to compare yourself (or your child) to a group. Perhaps the strongest statement that can be made is that it is very apparent that defining "success" by a reduction in the size of syrinx on MRI, is not necessarily linked to success from a symptom point of view.

Figure 1: Prevalence of Syrinx Specific Symptoms (49 Patients)

Symptom % With
Asymptomatic 20%
Parasthesia 49%
Dysesthesia 28%
Weakness 21%
Incontinence 15%
Gait Instability 8%
Scoliosis 41%

Figure 2: Improvement By Symptom

Symptom % Improved
Parasthesia 42%
Dysesthesia 73%
Weakness 75%
Incontinence 50%
Gait Instability 100%
Scoliosis 47%

Figure 3: Time Course of Symptom Improvement

Tracki1.gif

Note: Y axis = percent of patients with improved symptoms; X axis = time in months after surgery


Related C&S News Articles:

Fluid Motion Inside Syrinx Predicts Post-op Shrinkage

Study Shows Most Syrinxes Shrink Significantly Three Months After Surgery

Large Study Finds 80% Improve With Surgery

Surgery Improves Quality Of Life For About 80% Of Patients

Large Study Examines Surgical Outcomes In Children