Impact of anterior scalene lidocaine blocks on predicting surgical success in older patients with neurogenic thoracic outlet syndrome

Objective: Surgical management of neurogenic thoracic outlet syndrome (NTOS) is controversial due to the lack of predictors of success and difficulties in patient selection. We sought to examine the effects of patient demographics, etiology, duration of symptoms, and the selective use of lidocaine and botulinum toxin anterior scalene blocks on outcomes of patients undergoing transaxillary decompression with first rib resection and scalenotomy for NTOS. Methods: Patients with NTOS who had failed physical therapy and had transaxillary decompression between 2003 and 2009 were reviewed retrospectively from a prospectively maintained database. Patients were stratified to age groups <40 and <40 years old. Bivariate and multivariate statistical models of analysis were used. Results: One hundred fifty-nine procedures (16 patients bilateral; three patients with cervical ribs; 84.3% women; median age, 37 years; range, 21-64 years) were identified. Ninety-six patients were <40 and 63 were <40 years old. Etiology was similar in both groups: trauma 43% vs 46% and chronic repetitive motion 57% vs 54%. Duration of symptoms was less in the <40 group (38.4 vs 66 months; P <.05). More patients in the <40 group had other spine, shoulder, or arm operations (38% vs 18%; P <.05). Median follow-up for the cohort was 12 months. Transaxillary decompression was more likely to relieve symptoms in patients <40 vs <40 years old (90% vs 78%; P <.05). Lidocaine blocks were positive in 89% (49 of 55 patients) in the <40 group and 93% (43 of 46 patients) in the <40 group. After adjusting for patient presenting factors in multivariate analysis, the impact of a successful lidocaine block in patients <40 years old was greater than in patients <40 years old (improvement of surgical success of 14% in the >40 group vs 7% in the <40 group; P =.05). Botulinum toxin blocks were successful in less patients, 38% (eight of 21 patients) in the <40 group and 52% (12 of 23 patients) in the <40 group but were not predictive of symptom relief after transaxillary decompression. Conclusions: Although patients with NTOS <40 years old achieve more symptom relief overall after transaxillary decompression as compared to patients <40 years old, the selective use of lidocaine blocks is more beneficial in predicting surgical success in patients <40 years old given that younger patients <40 years old seem to do well regardless.