To the Editor:
We read with interest the article by Kupersmith et al. (1). The authors reviewed the natural history of brainstem malformations (cavernomas) and determined the rates of the intra- and extralesional hemorrhaging monitored by one neuro-ophthalmology service. In 37 patients with a mean of 4.9 years of follow-up monitoring, there were 27 bleeding events and 8 nonhemorrhagic events; two patients did not reexhibit symptoms. Cavernoma size was unchanged in 66.7%, smaller in 18%, and larger in only 15%. The authors concluded that rebleeding is not more common among patients who first present with bleeding and that it has little effect on the neurological status (morbidity rate, 8%).
In our series of surgically treated patients with brainstem cavernous malformations (2), only one of the nine patients had had a single bleeding episode before the operation. Five patients had had two bleedings, two patients had had three bleedings, and one patient had had four bleedings. The hemorrhages had occurred over a period of 6 months to 15 years. The Glasgow Outcome Scale score preoperatively was 5 in two patients, 4 in five patients, 3 in one patient, and hemiplegic sequelae in one patient. All patients had hemiparesis and/or cranial nerve palsies (2).
What the authors suggest—that not all cavernous malformations in the brainstem, even in the presence of bleeding, cause progressive neurological deficits, and that not every bleeding episode results in a significant neurological deficit—is controversial. We suggest that most patients with a brainstem cavernoma experience some degree of neurological deficit after the second bleeding. Even though our series consists of just a few cases, it sheds light on the relationship between the preoperative neurological status and the surgical results in patients with brainstem cavernomas who have experienced more than one bleeding. We do not agree with the authors that patients older than age 35 years exhibit a slightly lower risk of later bleeding. In our series, six of eight patients with rebleeding were older than 35 years of age. Most neurosurgeons know that hemorrhage or thrombus in a brainstem cavernoma cannot be the sole criterion for recommending surgical intervention. However, most patients with rebleeding present with clinical and neurological findings that are indications for surgical treatment. The authors’ rebleeding rate is within the ranges of rebleeding rates reported in the literature. Their view that patients with cavernous malformations who have rebleeding are not at high risk is not an acceptable conclusion, nor is it correct that brainstem cavernomas are benign lesions. Certainly, a true surgical indication after rebleeding is one component of good surgical results. Another important component is how to enter the brainstem during surgery, and this is still a challenge.
Ibrahim M. Ziyal
1. Kupersmith MJ, Kalish H, Epstein F, Yu G, Berenstein A, Woo H, Jafar J, Mandel G, De Lara F: Natural history of brainstem cavernous malformations. Neurosurgery 48: 47–54, 2001.
2. Ziyal IM, Sekhar LN, Salas E, Sen C: Surgical management of cavernous malformations of the brain stem. Br J Neurosurg 13: 366–375, 1999.