Diagnosis of GI neuromuscular diseases is mostly on the basis of symptomatology and is often unreliable. Pathologic analysis of affected tissue (eg, the myenteric plexus and muscle) is a potentially valuable method for both diagnosis and advancement of our knowledge about the biologic basis for these syndromes. However, until now access to the deeper layers of the GI tract has been limited, generally requiring invasive surgical techniques.

We report a “close-then-resect” endoscopic full-thickness biopsy sampling (EFTB) technique using an over-the-scope clip and telescope for rectal muscle biopsy sampling in patients with suspected severe neuromuscular gut disorders. The main outcome measures were technical success and adverse events.

Thirteen patients (11 women; mean age 27 ± 5.4 years) with diffusely delayed colonic transit underwent EFTB. The mean (± standard deviation) procedure time was 30 ± 5.2 minutes. The mean size of the resected specimen was 18 ± 3.5 mm. Histologic full-thickness tissue samples were achieved for all patients. Postprocedural adverse events were reported in 2 patients, and both were graded as mild (1 self-limited bleeding and 1 with rectal pain). Hematoxylin and eosin staining of tissue samples confirmed adequate cross-sectional imaging of muscularis propria in all patients with excellent demonstration of the myenteric plexus and both layers of muscle. Two patients demonstrated a decrease in interstitial cells of Cajal as demonstrated by CD117 staining. No cases demonstrated appreciable inflammation involving myenteric ganglia.

Diagnostic EFTB with modified over-the-scope clip for the close-then-resect method appears to be a safe and effective technique to obtain adequate full-thickness rectal specimens, allowing for both quantitative and qualitative analysis for the diagnosis of neuromuscular GI dysmotility.