Purpose: Published series of minimally invasive cervical foraminotomy (MICF) have shown excellent short-term relief of cervical radiculopathy (85–98%) with minimal surgical morbidity. There have been no long-term clinical series documenting the stability of these results over time. This is the first long-term follow-up of MICF patients to determine the incidence of recurrent symptoms and need for additional cervical spine surgery.

Methods: We conducted a multi-center retrospective chart review of 73 patients who had MICF. Clinical outcome measures were assessed from clinic records, operative records, and telephone surveys.

Results: At 3 months, 70/73 patients (96%) reported relief of radicular pain compared to their preoperative state. By 40 months, 15 patients reported symptoms of cervical radiculopathy. 8 patients experienced recurrent symptoms, and the remaining 7 had a new radicular pattern. Of 7 patients with symptoms at new levels, 6 had pre-existing radiographic abnormality. 15 patients underwent additional cervical surgery after MICF. 3 patients underwent repeat MICF at the same level. An additional 2 patients had MICF at a different level. 7 patients had ACDF at the same level and 2 had fusion at a different level. There were no cases of frank instability or spondylolisthesis noted.

Conclusions: At 40 month follow-up, 21% or patients had radicular symptoms with 11% reporting recurrence of preoperative symptoms and 9% with radicular symptoms in a different distribution. 12% (9/73 patients) of the group required ACDF within the follow-up period. Thus, 64/73 patients were spared fusion in this series. Assuming the 2.5% per year incidence of adjacent level fusion cited in the literature, there would have been 6 cases likely to have required another fusion if all 73 patients had been treated with ACDF initially. From this perspective, MICF continues to be our procedure of choice for properly selected patients with cervical radiculopathy.

Purpose: Inadequate disc fragment excision, suboptimal bony decompression of the lateral recess, and persistent foraminal and far lateral compressive lesions are the most common cited causes for persistent radiculopathy after lumbar decompressive surgery. This study examines the utility of continous intraoperative monitoring of electromyographic (EMG) nerve root potentials during decompression of lumbar radiculopathy using a proprietary neurophysiological EMG monitoring system (Neurovision; Nuvasive; San Diego, CA).

Methods: A prospective, non-blinded, non-randomized study was undertaken in 43 patients with symptomatic lumbar radiculopathy and weakness undergoing decompressive surgery. All had previously failed conservative therapy. Preoperative and postoperative data for neurological strength examination, EMG amplitudes, VAS scores for radiculopathy were recorded. Continuous EMG nerve root potentials were monitored and recorded during surgery.

Results: At the time of surgery, 39 of 43 patients demonstrated measurable asymmetric EMG amplitudes. Of these 39, 30 patients had clinical strength improvements. Intraoperative EMG improvements were seen in 21 of these 30 patients with an overall sensitivity of 70%. Of 9 patients who did not improve in strength, 8 demonstrated no improvement or worsening on EMG for a specificity of 89%. Overall, EMG nerve root monitoring had a positive predictive value of 95.5% and a negative predictive value of 47.1% with regards to strength improvement. 3 cases had worsened transient weakness that resolved within 3 months. In detecting such injury, EMG was 100% sensitive, 97% specific with a positive predictive value of 75% and a negative predictive value of 98%.

Conclusions: Use of intraoperative EMG nerve root surveillance may provide a useful adjunct in determining the adequacy of decompression during surgery of compressive lumbar radiculopathy and may help to predict the degree of motor improvement. Although a rare complication, EMG is particularly sensitive at detecting iatrogenic injury to the nerve root during surgery.