227 - What is the Learning Curve for MIS TLIF?...

#227 What is the Learning Curve for MIS TLIF?

MIS Techniques and Outcomes

Poster Presented by: F. Chan


F.J. Chan (1)
P. Kadimcherla (1)
A.D. Sharan (1)

(1) Albert Einstein College of Medicine, Bronx, NY, USA


Summary of Background Data: Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF) has emerged as an alternative to open Lumbar Fusion surgery for spondylolisthesis, degenerative disc disease, and recurrent disc herniation. The MIS TLIF procedure is technically more demanding than open fusion. Currently, there is a limited amount of literature concerning the learning curve and perioperative variables of MIS TLIF despite available published literature suggesting its overall advantage to open procedures.

Objective: To evaluate the learning curve, operative data, and early outcomes associated with MIS TLIF of one surgeon's experience.

Study Design: Retrospective review.

Methods: Retrospective review of one surgeon's first (61) MIS TLIF cases, using the operative report and patient's chart to evaluate operating time, length of hospital stay, estimated blood loss, ODI, and VAS scores. Using data from consecutive patients, OR time and length of hospital stay data were used to determine whether there was a significant difference (unpaired t-test) in early versus late cases. Starting with the first 10 patients and consecutively adding more patients to the early group, this group's OR time and LOS was compared to the remaining patients until a significant difference (p < 0.05) was detected. The number of patients required to reach this significant difference was noted as the proficiency point. Using this proficiency point, all other data was divided by the proficiency point and analyzed for significant differences.

Results: The medical records of the first 61 patients were evaluated. Operating time was found to be significantly less after 21 patients (3.12±0.78 hours versus 2.62±0.32 hours (P = 0.028). Length of stay was significantly shorter after 22 patients at 80.1 ±39.8 hours versus 56.3±51.7hours (P = 0.042). No significant difference was found when the first 22 patients were compared to the last 39 patients for estimated blood loss (P = 0.57), ODI scores (P = 0.77), and VAS scores (leg, P = 0.36; back, P = 0.58).

Conclusions: There is a significant learning curve associated with MIS TLIF. Significant differences were noted in OR time and length of hospital stay after 21 and 22 patients, respectively. Comparing the two groups on different parts of the learning curve, complication rates remained steady. Similar ODI and VAS scores were found at 3 months follow-up suggesting satisfactory outcomes even during the period of the learning curve.

Keywords: Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF), Learning curve, Procedure time, Length of stay.