327 - Motor and Neural Deficit Following Lateral Transpsoas Access...

#327 Motor and Neural Deficit Following Lateral Transpsoas Access

MIS Techniques and Outcomes

Poster Presented by: R. Amaral


R. Amaral (1)
R. Aquaroli (1)
L. Marchi (1)
T. Coutinho (1)
L. Oliveira (1)
L. Pimenta (1,2)

(1) IPC, Sao Paulo, Brazil
(2) UCSD San Diego, Neurosurgery, San Diego, CA, United States


Minimally invasive retroperitoneal transpsoas approach to lumbar spine has gained many of adepts in the last decade. The technique requires blunt dissection through the psoas muscle to reach the lumbar spine. It has been shown that it can cause some collateral effects related to the psoas muscle and the lumbar plexus which runs through. Thigh pain, numbness, paresthesias, and weakness are some examples. However the literature has not been able to

We conducted a prospective, non-randomized, controlled, single center study. 50 patients with mean age 62.4 years were enrolled. All subjects underwent to XLIF using EMG guidance. One to three lumbar levels were accessed in these cases (72% included L4L5). Isometric hip flexion strength at sitting position was determined bilaterally with a hand-held dynamometer. The mean of 3 peak force (N) measurements was calculated. Standardized isometric strength tests were performed preop and postop on day 10, 6 weeks, and 3 months. Isilateral and contralteral sides to the surgical access were compared. Quadriceps motor strength was measured in an I-V scale.

48% of the patients complained about some access-related symptom at the day 10 postoperatively. All patients that had some symptom presented hypoesthesia in the anterior thigh, while 34% had paresthesia, 10% had anterior thigh pain, and 12% had quadriceps deficit. At 3 months 8% complained about some numbness, but at minor compared to early postop symptom. One patient referred some anterior thigh pain and quadriceps deficit in the 3 months follow-up, but with focused physiotherapy had recovered 100% of preop muscle strength. Hip flexion was diminished (p< 0.001) at the early postop but at 6 weeks had reached preop values (p< 0.32). Mean values for hip flexion measures were: (Ipsilateral) 13.4N; 9.6N; 14.4N; 14.0N; (Contralateral) 12.9N; 13.4N; 15.1N; 14.4N. Neither the level nor the number of levels treated had clear association with thigh symptoms, but weaker the hip flexion was observed more thigh symptoms were found.

Postoperative period of XLIF present a high rate of immediate postoperative thigh symptoms. But in our study we have observed that they were transient. Thigh numbness is widely found in early postop period, as hip flexion weakness. EMG use is still imperative in transpsoas access and larger casuistic studies are required to complete the understanding and adequate nomenclature of those expected effects, collateral damages and complications.

Psoas Strength