77 Central Poststroke Pain

Deepa Danan and Christopher J. Winfree

Clinical Presentation

A 45-year-old woman sustained, 3 years ago, an acute onset of right hemibody numbness, followed a few hours later by right hemibody pain and paresthesias.

Initial brain magnetic resonance imaging scan revealed a small left thalamic infarct (Fig. 77.1).
The pain has persisted to the present time and involves the right side of her face, the right arm, trunk, and leg. It is sufficiently severe enough to interfere with her ability to work and carry out activities of daily living.
Physical examination is notable for decreased hemibody sensation in the painful distribution.

Questions

What is this patient’s diagnosis?
What are her treatment options?

The patient undergoes a variety of pharmacologic treatments, including multiple nonsteroidal antiinflammatory drugs, anticonvulsants, antidepressants, short-acting opiates, and long-acting opiates, none of which yielded sufficient pain relief. You are considering offering the patient more invasive treatment options.
What are some surgical options?

Fig. 77.1 Magnetic resonance imaging fluid-attenuated inversion-recovery without contrast of the head demonstrating the small, left-sided thalamic infarct.

Fig. 77.2 Intraoperative frameless stereotaxis magnetic resonance image demonstrating the localization of the central sulcus (C) and motor cortex (M). Identification of these landmarks facilitates the planning of a small craniotomy directly over the area of interest. Once the craniotomy is performed, somatosensory evoked potential phase reversal is performed to confirm the exact location of the central sulcus. The location of the facial and upper extremity motor cortex is confirmed when muscle contractions are elicited by transdural electrical stimulation. Once the array of stimulator electrodes is secured to the dura overlying the motor cortex, stimulation is increased until muscle contractions are noted, confirming the motor threshold. Postoperatively, stimulation intensities are kept well below the motor threshold to reduce the risk of postoperative seizures.