What is the learning curve for endoscopic spine surgery? A comprehensive systematic review.

BACKGROUND CONTEXT

Endoscopic spine surgery (ESS) is rapidly emerging as a viable minimally invasive technique to successfully treat symptomatic degenerative spinal conditions. Widespread adoption has been limited in part due to the learning curve.

PURPOSE

To systematically review the learning curve for uniportal and biportal ESS and compare the 2 techniques.

STUDY DESIGN/SETTING: A systematic review based on PRISMA guidelines.

PATIENT SAMPLE

About 29 studies were included with 18 studies investigating uniportal learning curves and 11 biportal studies. There were 1,493 patients across all uniportal studies. There was a total of 1,005 patients across all biportal studies.

OUTCOME MEASURES

Number of patients, technique type, patient reported outcomes, complications, operative time before the learning curve threshold, operative time after learning curve threshold, number of cases required to meet threshold, number of surgeons in the study, and cases per surgeon were collected and analyzed.

METHODS

A comprehensive literature search was conducted using PubMed, Medline, and Embase from 2000 to present date. Data was extracted by 3 independent reviewers.

RESULTS

The learning curve studies were reviewed and summarized. The overall median number of cases to reach the learning curve threshold was significantly less in uniportal vs biportal studies (20 vs. 37.5, p=.0463). When stratifying by various procedures, there was no significant difference between the techniques with number of cases required or improvement of operative time. Operative time for biportal discectomies decreased by a significantly greater amount vs uniportal. (44.5% vs. 21.4%, p=.0332).

CONCLUSIONS

The learning curve literature for ESS was systematically reviewed and ways to overcome the learning curve were discussed. The overall median number of cases for the learning curve was significantly fewer in uniportal vs biportal but the improvement in operative time was significantly greater with biportal discectomies, typically the entry level procedure by novice surgeons. Overcoming the learning curve for ESS is a critical factor to widespread adoption and understanding it may aid surgeons in progressing to proficiency while mitigating the risk of complications.