Mechanism of the Immediate Effect of Balloon Dilation Therapy in Spinal Muscular Atrophy With Dysphagia: A High-Resolution Manometric Study.

Balloon dilation therapy (BDT) is used to treat pharyngeal dysphagia in patients with impaired upper esophageal sphincter (UES) relaxation due to cricopharyngeal dysfunction. However, the mechanism underlying this immediate effect remains unclear. Here, we present a case in which we investigated the immediate effects of BDT on UES dysfunction using high-resolution manometry (HRM). A 67-year-old man was diagnosed with spinal muscular atrophy (SMA). He gradually developed dysphagia, and a gastrostomy was performed. Despite continuing oral intake of supplemental nutrition, the patient developed dysphagia. Videofluoroscopic (VF) examination of swallowing revealed pharyngeal residue, while HRM showed weak pharyngeal contractility and impaired UES opening. BDT was performed to address the UES dysfunction. Immediately following BDT, VF demonstrated improved pharyngeal bolus passage. As for the UES function during swallowing, HRM revealed that the UES relaxation duration was significantly longer and the UES nadir pressure was significantly decreased. The patient continued the BDT before oral intake. HRM revealed immediate and prolonged UES opening with decreased UES pressure during swallowing as an immediate effect of BDT. This suggests that these findings represent the mechanisms underlying dysphagia in this patient with SMA. BDT resulted in an immediate improvement in UES function, potentially leading to dysphagia improvement. BDT should be combined with conventional rehabilitation for impaired UES opening. However, further studies are needed to confirm the long-term effectiveness of BDT for dysphagia due to SMA.