Transforaminal lumbar endoscopic discectomy (TLED) is a minimally invasive surgery for removing lumbar disc herniations. This technique was initially reserved for herniations in the foraminal or extraforaminal region.
It seems to be a promising technique to effectively treat LDH. The reported complication rate of PTED is low, as is the percentage of patients requiring additional surgery due to recurrent LDH. Due to its steep learning curve, however, PTED should be further investigated before widespread implementation. Open microdiscectomy remains the current standard therapy for the surgical decompression of LDH. High-quality randomized controlled trials are needed to generate Class I evidence on the efficacy and cost-effectiveness of PTED 1).
A technique for percutaneous nonvisualized indirect spinal canal decompression—percutaneous nucleotomy— through a posterolateral approach was described by Parviz Kambin in 1973 2) and Hijikata et al. in 1975. 3).
Kambin described using a Craig cannula and Hijikata a 2.6-mm cannula. The technical challenge of achieving sufficient removal of nucleus pulposus material through a needle was addressed by Kambin and coworkers in 1986 and 1987 with the introduction of working cannulas possessing diameters up to 5 mm and flexible forceps 4) 5).
The next step in the advancement of the percutaneous discectomy technique was the addition of the endoscope. The first endoscopic views of a herniated nucleus pulposus were published by Kambin et al. in 1988 6) and the first reported introduction of a modified arthroscope into the intervertebral disc space was reported by Forst and Hausman in 1983 7)
Schreiber et al. 8) and Suezawa et al. 9) published their bilateral approach for a percutaneous nucleotomy under endoscopic control and described injecting indigo carmine into the disc space to stain the abnormal nucleus pulposus and anular fissures.
Percutaneous endoscopic discectomy certainly must receive a great portion of the credit for advancing endoscopic spine surgery, but it also must likely take responsibility for endoscopic spine surgery's slow rate of acceptance as a feasible technique by most orthopedic and neurosurgical spine specialists. The surgical goal of percutaneous endoscopic discectomy is to indirectly decompress the neural elements by selectively removing the nucleus pulposus from the posterior one-third of the disc space. From its origin, the technique showed promising results: Kambin and Gellman reported a 72% success rate in 136 patients with their percutaneous technique in 1983, but it has been difficult to quantify the impact of such results because they were not matched with nonoperative controls 10)
It has several advantages over open lumbar discectomy, including less paravertebral muscle injury, preservation of bony structure, and rapid recovery, and has gained popularity for removal of herniated disc (HD) material over the past few years since Kambin 11) introduced the percutaneous posterolateral approach in 1983.
Even sequestered disc material - regardless of its size and level - that slipped into the spinal channel can be removed with the minimal invasive method.
Large, uncontained, lumbar disc herniations can be sufficiently removed with remarkable long-term outcome. Although the neurological outcome is the same, the morbidity is significantly less than open discectomy. Maximum benefit can be gained if we adhere to strict selection criteria. The optimum indication is single- or multi-level radiculopathy secondary to a single-level, large, uncontained, lumbar disc herniation 12).
Proper surgical indications and good working channel position are important for successful PELD. PELD techniques should be specifically designed to remove the disc fragments in various types of disc herniation 13).
Immediate pain relief in 95% of the cases - study info needed
Direct access to herniated disc/sequester
The disc-annulus and the ligament remain intact
No general anesthesia, only a sparing local anesthetic necessary
Shorter rehabilitation -study info needed
Faster return to profession and everyday life - study info needed
Small incision (only one stitch) = hardly any scarring.
For adjacent segment degeneration (ASD) and recurrent lumbar disc herniation, PELD had more advantages over open lumbar surgery in terms of reduced blood loss, shorter hospital stay, operating time, fewer complications, and less postoperative discomfort 14).
It can be performed under local anesthesia and requires only an 8-mm skin incision.
According to a nationwide cohort study, there is no significant difference in the reoperation rates between open discectomy (13.7%) and endoscopic discectomy (12.4%) 20).
PELD may not be an applicable option for all ages.
Kim et al. selected 15,817 patients who underwent open discectomy (n = 12,816) or PELD (n = 3,001) in 2003 from Korean Health Insurance Review & Assessment Service (HIRA) database. All patients in the cohort were followed until December 31, 2008, and the minimum follow-up period was 5 years. A time to event survival analysis was performed. Primary end-point was any type of second lumbar spine surgery during the follow-up period. Minimum P-value approach and two-fold cross validation approach were utilized to determine an age cut-off point.
The optimal age cut-off point was determined as 57 years. PELD for elder patients (≥ 57 years) had a higher reoperation risk during postoperative 3.4 years (Hazard ratio [HR] at 1 yr, 1.75; 2 yr, 1.57; 3 yr, 1.41). However, re-operation risk was not higher after PELD for patients of < 57 years from 1.9 years than open diskectomy (HR at 2 yr, 0.86; 3 yr, 0.78; 4 yr, 0.70; 5 yr, 0.63).
In the present study, they showed that an age cut-off point of PELD for optimal reoperation rate may be 57 years with national-wide population based data. Reoperation rate seems to be not higher for patients younger than 57 years after PELD than open diskectomy, but applying PELD for elder patients need careful consideration 21).
Mahatthanatrakul et al., reviewed patients who underwent TELD. Clinical data obtained were Oswestry disability index (ODI) and visual analog scale (VAS) for back and leg pain. Residual mass signal and disc protrusion size were measured in postoperative MRI.
Thirty-one patients were reviewed. The mean age was 38.3 ± 14.4 years (range 18 to 76 years). ODI was 18.2% at the first follow-up and 12.7% at the last follow-up (p = 0.009). VAS for back and leg pain were 2.0 and 1.0 without significant change during follow-up. Disc protrusion size was reduced by 67.7% at the 1-year follow-up (p < 0.001). The residual mass signals at postoperative day 1 were high in 12 cases, intermediate in 18 cases, and low in1 case. The signal intensity was correlated with the percentage of disc protrusion reduction (p = 0.048). The percentage of disc protrusion reduction correlated with the last follow-up ODI (p = 0.018).
One year after TELD, annulus remodeling was observed with an average of 67.7% of size reduction. The high signal intensity of residual mass at day 1 correlated with disc protrusion reduction at follow-up MRI. The percentage of disc protrusion reduction associated with the ODI at the final follow-up 22).
164 patients who were less than 60 years old, complained of unilateral leg pain. Kim et al. measured the maximum trunk shift from the central sacral vertical line (CSVL-max) on preoperative whole spine radiographs and classified trunk list as CSVL-max ≥ 10 mm. CSVL-max was measured on serial radiographs taken at one, 3, 6, and 12 months postoperatively in patients with trunk list.
Twenty-nine patients (17.9%) had trunk list (M:F=10:19; mean age, 37.1 ± 11.24 years). Female gender (OR 4.28; 95% CI, 1.49 - 12.3) and HIVD at L4-5 (OR 5.6; 95% CI, 1.8 - 16.7) were risk factors for trunk list. Trunk list was normalized (CSVL-max < 10 mm) in 15 (52%) patients after PELD, and the median time for normalization was 3 - 6 months. Prognostic factors for the recovery of trunk list were not identified.
Selection bias should be considered in interpreting these results.
Trunk list, scoliosis or lateral shift, was observed in 18% of the patients at the time of surgery. Female gender and L4-5 disc herniation were risk factors for trunk list. Trunk list was reversible in more than 50% of patients within 6 months of PELD 23).
201 patients had endoscopic discectomy and the mean age was 41 years. Male:female ratio was 1.3:1.0. Mean time of onset of symptoms was 5.5 months and the most common level was L4/5 (53%). All endoscopic discectomies were performed under local anesthesia. Theater time was on average 110min. 10 patients were lost to follow up. 95% of patients were discharged within 7h post operatively. Visual acuity score of the pain dropped from an average of 7/10 pre-operatively to 0-1/10 in 95% of patients two weeks post operatively. 87% patients went back to their normal daily activities within two weeks. There were no cases of CSF leak, hematoma formation or wound infection. 1% of patients developed a nerve root injury. 6% of patients had recurrent herniation and require microdiscectomy.
Endoscopic discectomy can be an alternative approach to microdiscectomy. While it can take more expertise to perform endoscopic discectomy, the data shows that the far lateral endoscopic discectomy using the TESSYS technique has comparable outcomes to microdiscectomy 24).
A total of 105 patients were included in the study. The patients were retrospectively evaluated for demographic features, lesion levels, numbers of affected levels, visual analog scores (VASs), Oswestry disability questionnaire scale scores and MacNab pain relief scores.
A total of 48 female and 57 male patients aged between 25 and 64 years (mean: 41.8 years) underwent TLED procedures. The majority (83%) of the cases were operated on at the levels of L4-5 and L5-S1. Five patients had herniations at two levels. There were significant decreases between the preoperative VAS scores collected postoperatively at 6 months (2.3) and those collected after 1-year (2.5). Two patients were referred for microdiscectomy after TLED due to unsatisfactory pain relief on the 1(st) postoperative day. The overall success rate with respect to pain relief was 90.4% (95/105). Seven patients with previous histories of open discectomy at the same level reported fair pain relief after TLED.
Transforaminal lumbar endoscopic discectomy is a safe and effective alternative to microdiscectomy that is associated with minor tissue trauma. Herniations that involved single levels and foraminal/extraforaminal localizations were associated with better responses to TLED 25).
A total of 280 consecutive patients with a primary herniated, including sequestrated, lumbar disc with predominant leg pain, was randomized. A clinical follow-up was performed at 3 months, and at 1 and 2 years after the index operation with an extensive questionnaire, including the visual analog scale for pain and the MacNab criteria. The cohort integrity at 3 months was 100%, at 1 year 96%, and at 2 years 92%. RESULTS:
At the 3-month evaluation, only minor complications were registered. At 1-year postoperatively, group 1 (endoscopy alone) had a recurrence rate of 6.9% compared to group 2 (the combination therapy), with a recurrence rate of 1.6%, which was a statistically significant difference in favor of the combination therapy (P = 0045). At the 2-year follow-up, group 1 reported that 85.4% had an excellent or good result, 6.9% a fair result, and 7.7% were not satisfied. At the 2-year follow-up, group 2 reported that 93.3% had an excellent or good result, 2.5% a fair result, and 4.2% were not satisfied. This outcome was statistically significant in favor of the group including chymopapain. There were no infections or patients with any form of permanent iatrogenic nerve damage, and no patients had a major complication. CONCLUSIONS:
A high percentage of patient satisfaction could be obtained with a posterior lateral endoscopic discectomy for lumbar disc herniation, and a statistically significant improvement of the results was obtained when an intradiscal injection of 1000 U of chymopapain was added. There was a low recurrence rate with no major complications. The method can be applied in any type of lumbar disc herniation, including the L5-S1 level 26).