Percutaneous Endoscopic Interlaminar Discectomy via Laminoplasty Technique for L₅ -S₁ Lumbar Disc Herniation with a Narrow Interlaminar Window

To improve the treatment effect of patients with L₅ S₁ lumber disc herniation (LDH) with a narrow interlaminar window, we proposed an alternative approach to percutaneous endoscopic interlaminar discectomy (PEID) via the laminoplasty technique.

Fifteen L₅ S₁ LDH patients (7 men and 8 women; age range, 22 to 56 years; median age, 34 years; 9 left, 6 right) were enrolled in the present study retrospectively. The interlaminar windows of all patients were narrow (the transverse diameter of the L₅ S₁ interlaminar window is equal to or less than that of L_4-5 ). Percutaneous laminoplasty and endoscopic interlaminar discectomy surgery were undergone by all patients from July 2018 to July 2019. All operations were completed under local anesthesia. The target laminoplasty area was the safety zone, use of which avoids both transverse and exit nerve roots. Under fluoroscopic guidance or clear endoscopic visualization, the trephines were used to enlarge the interlaminar window, which allowed the working cannula to enter the spinal canal but avoid nerve roots and the dural sac. The preoperative/postoperative visual analogue scale (VAS) scores and Oswestry disability index (ODI) were statistically analyzed. The modified MacNab criterion was used to assess the clinical effects. The radiological outcomes were evaluated by MRI and CT. SPSS 19.0 software was used for the statistical evaluation.

The operative time ranged from 70 to 120 min, with a median time of 92 min, and the fluoroscopy times ranged from 8 to 12, with a median of 9.7 times. The body mass index (BMI) of patients ranged from 18.10 to 26.06, with a median of 22.04. All patients were followed up in the outpatient department for at least 12 months after surgery. At the last follow up, the average VAS-Back score of the study patients was reduced from 5.33 ± 2.09 to 2.00 ± 1.20 (P < 0.001) and the average VAS-Leg score was reduced from 7.53 ± 1.69 to 1.47 ± 0.92 (P < 0.001). The average ODI scores improved from 47.87 ± 11.41 to 12.93 ± 3.24 (P < 0.01). According to the modified MacNab criteria, 11 cases achieved excellent results and 4 cases achieved good results. All of the operations were successful. There wertr no nerve root injuries, dural tears, or other complications.

The laminoplasty approach for PEID provides a safe and useful alternative for the treatment of L5-S1 LDH patients with a narrow interlaminar window.