Intraoperative measurement of pharynx/esophagus retraction during anterior cervical surgery. Part II: perfusion

Abstract

Early postoperative dysphagia after anterior cervical surgery is a well-known phenomenon with so far unknown etiology. We hypothesised that direct pressure induced by the medial retractor blade on pharynx/esophagus mucosal wall leads to local ischemia. Subsequently postoperative hyperemia and swelling of the pharynx/esophagus may result in swallowing disturbance. To prove the hypothesis local blood flow inside the pharynx/esophagus wall during anterior cervical surgery was measured using a laser Doppler (LD) perfusion monitor unit. Fifteen patients underwent standard anterior cervical discectomy and fusion (ACDF). The LD probe was placed underneath the medial retractor blade in order to gain information at the maximum point of pressure applied onto the pharynx/esophagus wall. Local perfusion was measured prior to retractor opening (5 min), during spreading of the retractor and after its closure (5 min). Perfusion was measured semiquantitatively in perfusion units (PU). Local perfusion ranged from 30 to 210 PU (mean 107) prior to retractor opening, from 7 to 60 PU (mean 30) with open retractor and from 15 to 280 PU (mean 117) after retractor closure. In all 15 patients the open retractor led to hypoperfusion ranging from 21 to 93% compared to the baseline level. In seven patients a reactive hyperemia at the end of the procedure was detected (32-89% compared to baseline level). In four patients after hypoperfusion during spreading of the retractor the baseline levels were reached again and in four patients perfusion remained diminished even after retractor closure. To best of our knowledge, this is the first report on intraoperative measurement of local perfusion of the pharynx/esophagus wall during anterior cervical surgery. Diminished local perfusion was observed in all patients during spreading of the retractor and post-procedure hyperemia was recorded in 46% of the patients. The local ischemia of the pharynx/esophagus wall may be a crucial step in the development of postoperative dysphagia.

Voice and swallowing outcomes following reoperative anterior cervical discectomy and fusion with a 2-team surgical approach

“…VCP may be due to sectioning or retraction injury of the RLN, retraction of the esophagus with reduced perfusion, 21 direct pharyngeal or esophageal pressure, 22 hypoglossal nerve injury, 35 or alteration in C2-7 angle. 36,47 Injury to the superior laryngeal nerve (particularly in high approaches) is also a cited cause, and although not well documented in the ACDF literature, is a well-known cause of dysphagia following oncological surgery of the neck.…”

Anterior cervical spine surgery-associated complications in a retrospective case-control study

“…However, there are studies supporting the theory that soft tissue swelling is not related to the development of postoperative dysphagia (46,48). Various causes have been implicated in the development of postoperative dysphagia, including RLN palsy, pharyngeal plexus denervation, esophageal direct injury, and regional esophageal ischemia (71)(72)(73)(74)(75). In addition, postoperative hematoma and scar tissue formation should be ruled out, especially in cases of chronic dysphagia (76).…”

The Impact of Esophagus Retraction on Early Dysphagia After Anterior Cervical Surgery

“…This method has been described previously in detail. 10 Mean arterial pressure and endotracheal cuff pressure were also recorded online. After opening of the retractor, the endotracheal cuff pressure was adjusted to 20 mm Hg.…”