The location of the intervertebral lumbar disc on the posterior aspect of the spine

Imaging anatomy study related to unilateral biportal endoscopic lumbar spine surgery

PURPOSE

To provide lumbar spine anatomical parameters relevant to the UBE technique and explore their intraoperative application.

METHODS

CT imaging data processed by Mimics for parametric measurements, including laminar abduction angle (LAA), laminar slope angle (LSA), minimum laminar height (MLH), distance between the inferior margin of the lamina and attachment of the ligamentum flavum onto the cephalad lamina (DLL), distance between the initial point and the middle of the articular process (DIA), and distance from the inferior margin of the lamina to the inferior border of the vertebral body (DLV), and were manually measured.

RESULTS

LAA and DIA gradually increase from L1 to L5. At L1, the DIA is approximately the length of 2 drill bits with a diameter of 3 mm (male: 7.77 ± 1.39 mm, female: 7.22 ± 1.09 mm), while at L5, it can reach the length of 4-5 drill bits (male: 14.96 ± 2.24 mm, female: 13.67 ± 2.33 mm). MLH, DLL, and DLV reach their maximum values at the L3 and decrease toward the cranial and caudal ends. The DLL is smallest at L5 (male: 9.58 ± 1.90 mm, female: 9.38 ± 2.14 mm), equivalent to the length of 3 drill bits, while the DLL at L3 is the length of 4-5 drill bits (male: 14.17 ± 2.13 mm, female: 14.01 ± 2.07 mm).

CONCLUSION

Referring to the drill diameter during surgery can mark the extent of laminotomy. The characteristics of vertebral plate angles at different lumbar levels can provide references for preoperative incision design.

Spinal anesthesia for L5-S1 interlaminar endoscopic lumbar discectomy: a retrospective study

OBJECTIVE

This study aimed to report our experience with spinal anesthesia (SA) in patients undergoing L5-S1 interlaminar endoscopic lumbar discectomy (IELD) and clarify its advantages and disadvantages.

METHODS

One hundred twelve patients who underwent IELD for an L5-S1 disc herniation under SA were retrospectively analyzed. SA with 0.5% ropivacaine was administered using a 27-gauge fine needle. Intraoperatively, the volume and level of SA, surgical time, blood loss, and cardiopulmonary complications were documented. Postoperative data was collected included the number of patients who ambulated on the day of surgery, incidence of complications and were then statistically analyzed.

RESULTS

Analgesia was complete throughout the entire operation in all patients and no other adjuvant intraoperative analgesic drugs were needed. Mean visual analog scale scores for intraoperative and early postoperative (24 h) pain were 0 and 2.43 ± 1.66. SA was administered at the L3-4 interspace in 34 patients (30.4%) and the L2-3 interspace in 78 (69.6%). Administration was successful with the first attempt in all patients. Mean operation time was 70.12 ± 6.52 min. Mean intraoperative blood loss volume was 20.71 ± 5.26 ml. Ninety-eight patients ambulated on the same day as surgery. Mean length of hospital stay was 24.36 ± 3.64 h. Dural injury without damaging the nerve root occurred in one patient. One patient experienced recurrent disc herniation. Intraoperative hypotension and respiratory distress occurred in five (4.5%) and three (2.7%) patients, respectively. Three patients (2.7%) received postoperative analgesia therapy and two (1.8%) experienced nausea. Two patients (1.8%) developed urinary retention. Spinal headache, cauda equina syndrome, and neurotoxicity did not occur.

CONCLUSION

SA can achieve satisfactory pain control for patients undergoing IELD with a low incidence of adverse events. SA may be a useful alternative to local and general anesthesia for IELD surgery. Future randomized controlled trials are warranted to investigate.

Spinal sonography and central neuraxial blocks

Central neuraxial blocks (CNBs), which include spinal, epidural, and combined spinal epidural injections, are indispensable techniques in the anesthesiologist's armamentarium. Indeed, in scenarios such as when dealing with the obstetric population, patients with obesity, or patients having respiratory compromise (e.g., lung disease or scoliosis), CNBs are the mainstay for anesthesia and/or analgesia. Traditionally, CNBs are performed using anatomical landmarks, which are simple, easy to master, and exceptionally successful in most cases. Nevertheless, there are notable limitations with this approach, especially in scenarios where CNBs are considered mandatory and vital. Any limitation of an anatomic landmark-based approach is an opportunity for an ultrasound-guided (USG) technique. This has become particularly true for CNBs, where recent advances in ultrasound technology and research data have addressed many of the shortcomings of the traditional anatomic landmark-based approaches. This article reviews the ultrasound imaging of the lumbosacral spine and its application for CNBs.

An overview of lumbar anatomy with an emphasis on unilateral biportal endoscopic techniques: A review

Unilateral biportal endoscopy (UBE) is a major surgical technique used to treat degenerative lumbar diseases. The UBE technique has the advantages of flexible operation, high efficiency, and a large observation and operation space. However, as a typical representative of minimally invasive techniques, UBE still needs to complete a wide range of decompression and tissue resection in a narrow working space, resulting in many surgery-associated injuries. Therefore, it is necessary to reduce complications by familiarity with the anatomy of the lumbar spine. Based on the UBE technique, this review article provides historical and current information on the anatomical structures of the lumbar vertebrae, such as the articular process, pedicle, lamina, ligamentum flavum, nerve root, intervertebral disc, and artery supply.

Massively prolapsed intervertebral disc herniation with interlaminar endoscopic spine system Delta endoscope: A case series

BACKGROUND

Surgery is often indicated for patients with massively prolapsed intervertebral disc herniation. The interlaminar endoscopic spine system (iLESSYS) Delta 6-mm working channel endoscope has advantages over other systems. The aim of this study was to explore the benefits and complications of using the iLESSYS Delta for the treatment of massively prolapsed intervertebral disc herniation.

AIM

To explore the clinical benefits of treating massively prolapsed lumbar intervertebral disc herniation with the iLESSYS Delta endoscope.

METHODS

In this study, the data of 37 patients who underwent surgery with the iLESSYS Delta endoscope at The Affiliated Hospital of Qingdao University were retrospectively analyzed. Intraoperative blood loss, operation time, and complications were collected. The visual analog scale (VAS), oswestry disability index (ODI), and modified MacNab criteria were determined before and at 1 d, 3 mo, and 6 mo after surgery.

RESULTS

The mean intraoperative blood loss was 20.4 ± 1.2 mL. The mean operation time was 97.3 ± 12.4 min. The VAS scores for leg and back pain decreased from 68.0 ± 7.3, 34.4 ± 8.5 before operation to 2.5 ± 1.7, 5.5 ± 1.9 at 6 mo after surgery, respectively. The ODI also decreased from 60.2 ± 7.3 to 17.9 ± 3.4 at 6 mo after surgery. The improvement rate of the MacNab score was 86.4%, which was considered excellent. No spinal dural injury, nerve root injury, secondary protrusion of intervertebral disc, or myeloid hypertension was found during follow-up.

CONCLUSION

The iLESSYS Delta 6-mm working channel endoscope has several advantages in terms of clinical and functional benefits, complications, and low risk of residual vertebral pulp in treating patients with massively prolapsed intervertebral disc herniation.

Early Clinical Outcomes of Percutaneous Endoscopic Lumbar Discectomy for L4-5 Highly Down-Migrated Disc Herniation: Interlaminar Approach Versus Transforaminal Approach

OBJECTIVE

This study is a retrospective evaluation of patients with L4-5 highly down-migrated lumbar disc herniation (LDH) operated with interlaminar endoscopic lumbar discectomy (IELD) versus transforaminal endoscopic lumbar discectomy (TELD).

METHODS

From January 2015 to December 2018, 77 patients with L4-5 highly down-migrated LDH were divided into 2 groups according to different surgical approaches. There were 40 patients who underwent IELD, and 37 patients who underwent TELD. The operation time, hospital stay, Oswestry Disability Index, clinical outcome according with modified MacNab criteria, Visual Analog Scale (VAS) scores, and complications were compared between the IELD and TELD groups.

RESULTS

Seventy-seven patients were included, 40 and 37 patients underwent IELD and TELD, respectively. The IELD and TELD groups both achieved a significant improvement in Oswestry Disability Index, back and leg VAS scores, and clinical outcome postoperation. Mean operating and x-ray times during operation were significantly shorter in the IELD group than in the TELD group (41.8 vs. 50.3, 1.8 vs. 13.7). There were 3 patients who experienced recurrence in the IELD group and 2 in the TELD group. In the TELD group, there were 3 patients who required revision surgery due to incompletely removed disc fragment. All patients in the IELD group were treated successfully. There was no other complication in these cases.

CONCLUSIONS

Both IELD and TELD could be a good alternative option for highly down-migrated LDH in L4-L5. IELD may have advantages in operation time and x-ray times during operation compared with TELD.

Gradient local anesthesia for percutaneous endoscopic interlaminar discectomy at the L5/S1 level: a feasibility study

BACKGROUND

During the process of shearing the ligamentum flavum, rotating the working channel, and manipulating the annulus fibrosis, the sinuvertebral nerve and the spinal nerve root can be irritated, inducing intolerable back and leg pain. Thus, general anesthesia is recommended and well accepted by most surgeons when performing percutaneous endoscopic lumbar discectomy (PELD) via the interlaminar approach. The aim of our study was to explore the efficacy and safety of percutaneous endoscopy interlaminar lumbar discectomy with gradient local anesthesia (LA) in patients with L5/S1 disc herniation.

METHODS

This retrospective study was conducted between December 2017 and June 2018. The study included 50 consecutive patients who met the study criteria, had single-level L5/S1 disc herniation, and underwent PELD via the interlaminar approach under gradient LA. Different concentrations of local anesthetic compound (LAC) were injected into different tissues inside and outside the ligamentum flavum to complete gradient LA. The evaluation criteria included the intraoperative satisfaction score, visual analog scale (VAS) score, Oswestry Disability Index (ODI), complications, and adverse reactions.

RESULTS

The intraoperative satisfaction score was consistently over 7, with an average score of 9.3 ± 0.7, indicating that LAC can achieve satisfactory pain control throughout the PELD operation without additional anesthesia. The postoperative VAS score and ODI were dramatically improved at each follow-up interval (P < 0.001, respectively). There was no serious complication such as dural rupture caused by puncture, dural laceration caused by manipulation under endoscopy, total spinal anesthesia, iatrogenic nerve root injury, epidural hematoma, infections, or local anesthetic-related adverse reactions. Three patients experienced transient postoperative dysesthesia of the lower limbs that gradually recovered within 24 h.

CONCLUSIONS

Gradient local anesthesia can satisfactorily and safely control intraoperative pain during the PELD via the interlaminar approach. It can not only improve intraoperative satisfaction, but also reduce local anesthesia-related adverse reactions and surgery-related complications.

The evolution of interlaminar endoscopic spine surgery

Due to the aging population, patients required spinal surgery for degenerative spondylopathy is increasing. With the advent of surgical instruments and techniques, minimally invasive spine surgery is prevalent worldwide. Besides microscopic techniques, endoscopic spine surgery has gotten attention gradually in this surgical field for the past two decades. There are two essential approaches developed currently, including transforaminal and interlaminar approach. These innovative equipment and skills promote the progression of endoscopic surgery from discectomy to decompression of spinal stenosis. Meanwhile, they also opened up the application of endoscopic surgery in a complicated situation. From the perspective of emerging technologies and techniques, the authors will review the evolution and describe the prospects of the interlaminar endoscopic spine surgery (IESS).

WITHDRAWN: Modified Full-Endoscopic Interlaminar Discectomy via an Inferior Endplate Approach for Lumbar Disc Herniation: Retrospective 3-Year Results from 321 Patients

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Treatment of L5 - S1 intervertebral disc herniation with posterior percutaneous full-endoscopic discectomy by grafting tubes at various positions via an interlaminar approach

Background

Depending on the location of the herniated disc at the shoulder, axilla, or ventral side of the compression nerve root, various puncture sites and channel entrances were selected so that the goal of targeted removal of the herniated disc could be achieved by a full-endoscopic technique. Achieving good clinical therapeutic efficacy through the natural gap of bones can maximally avoid related access complications, and the necessary techniques and relevant anatomical factors were analyzed.

Methods

Between August 2012 and August 2014, 98 patients with L5 - S1 intervertebral disc herniation were treated with posterior percutaneous full-endoscopic discectomy (PPFED) by grafting tubes at various positions via the interlaminar approach. The visual analog scale (VAS) and the Oswestry disability index (ODI) were used to assess the patients’ back and leg pain and the improvements in daily function, and the modified Macnab standard was used to evaluate the treatment efficacy.

Results

All 98 patients successfully completed the surgery, 84 patients got out of bed and walked on the first postoperative day, and 14 patients got out of bed and walked on the second postoperative day. The preoperative ODI (56.032 ± 3.625) was significantly higher than the ODI score (8.147 ± 1.398) (F = 5343.054, P ≤ 0.001) 48 months after surgery. The preoperative VAS score (7.193 ± 0.875) was significantly higher than the postoperative VAS score (0.914 ± 0.500 points) (F = 1656.173, P ≤ 0.001). The differences in ODI and VAS scores before and after surgery were statistically significant (P < 0.05). Follow-up was conducted 1, 6, 12 and 48 months postoperatively, and the modified Macnab standard was used during the last follow-up to evaluate the efficacy: 67 cases were excellent, 20 cases were good, 7 cases were fair, and 0 cases were poor; the proportion of excellent and good cases was 92.6%.

Conclusions

The treatment of L5 - S1 intervertebral disc herniation with PPFED by grafting tubes at various positions via an interlaminar approach is a safe, effective, and minimally invasive surgical method. Reaching the location of a disc herniation directly through the natural gap in the bones can maximally avoid collateral injury from spine surgery.

Trial registration

The registration number of this clinical study is ChiCTR1800014588; it has been retrospectively registered with a registration date of 05/01/2018.

Preganglionic Epidural Steroid Injection through Translateral Recess Approach

The approach we suggest was developed for cases in which the fourth and fifth lumbar and first sacral spinal nerves were affected in lumbar degenerative disc disease. Retrodiscal transforaminal epidural injection is known to be very effective for lumbar radiculopathy because of excellent access to primary pathology; however, access below L5 is often restricted by the anatomic characteristics of the L5-S1. In the translateral recess approach (TLR), proper final needle placement (i.e., in the axillary portion between the exiting and traversing nerve roots) can be achieved by setting the direction of the needle laterally and superiorly from the distal tip of the infra-adjacent spinous process toward the medial wall of the pedicle and neural foramen of the given level without neural injury. This approach is possible because of the wide interlaminar space in the L5-S1. Preganglionic epidural injection through TLR is an effective and safe spinal intervention for lumbosacral radiculopathy.

Advantages of a Microsurgical Translaminar Approach (Keyhole Laminotomy) for Upper Lumbar Disc Herniation

BACKGROUND

To prevent risk of iatrogenic instability after surgery for upper lumbar disc herniation, we adapted a microsurgical translaminar approach (keyhole laminotomy), which allows less destructive laminotomy. We compared results of translaminar and interlaminar approaches.

METHODS

The study enrolled 48 patients who underwent single-level discectomy in the upper lumbar spine (L1-2 or L2-3). Patients were allocated to 2 groups: a translaminar group (n = 20) or an interlaminar group (n = 28). Mean patient age was 57.04 ± 12.77 years, and median follow-up duration was 3.5 years (range, 1.0-7.0 years). Clinical and radiologic data were retrospectively reviewed.

RESULTS

Baseline characteristics, including age, sex, surgical level, and preoperative symptoms, were nonsignificantly different. At 1 year after surgery, improvement in leg pain as determined by visual analog scale was nonsignificantly different. Improvement in visual analog scale for back pain was significantly greater in the translaminar group compared with interlaminar group (mean 4.00 ± 1.56 vs. 2.45 ± 2.01, P < 0.001). Surgical outcome was not different between groups. Mean decrease in disc height at operated level was not significantly different between groups. Mean increase in segmental range of motion at surgical levels was significantly greater in the interlaminar group (-3.38 ± 4.03° vs. 1.10 ± 3.03°, P = 0.010), and mean recovery of total lumbar lordosis was significantly greater in the translaminar group (9.80 ± 5.96° vs. 0.43 ± 8.45°, P = 0.021).

CONCLUSIONS

The translaminar approach provides a safe and effective alternative to the classic interlaminar approach for upper lumbar disc herniation.

Percutaneous endoscopic interlaminar discectomy of L5-S1 disc herniation: a comparison between intermittent endoscopy technique and full endoscopy technique

Background

Percutaneous endoscopic laminar discectomy is a typical minimally invasive discectomy operation that is classified into the percutaneous endoscopic transforaminal discectomy and the percutaneous endoscopic interlaminar discectomy. Based on whether the surgeon chooses to deal with the ligamentum flavum under endoscope guidance, percutaneous endoscopic discectomy by the interlaminar approach can be performed with a full endoscope technique with the intermittent endoscope technique. To our knowledge, there is no study comparing these two techniques in regard to their surgical effects and advantages. Therefore, we conducted this study to compare the cost, safety, and efficacy between the intermittent endoscopy technique and full endoscopy technique of endoscopic interlaminar lumbar discectomy at the L5–S1 level.

Methods

From September 2014 to March 2015, a total of 126 patients with radiculopathy due to L5–S1 disc herniation who were treated by a full endoscopy technique (65 patients) or intermittent endoscopy technique (61 patients) were included. Relevant data, such as duration time of the operation, hospitalization expenses, postoperative bed rest time, length of hospitalization, and complication rates, were recorded. Clinical outcomes were assessed by the visual analog scale score, modified MacNab criteria, and Oswestry disability index.

Results

In the full endoscope (FE) group, the mean duration time of surgery was 75.0 ± 11.9 min. The postoperative bed rest time was 6.5 ± 1.1 h, length of hospitalization was 3.8 ± 1.1 days, and complication rate was 7.69%. In the intermittent endoscopy (IE) group, the mean duration time of surgery was 43.0 ± 16.4 min. The postoperative bed rest time was 5.0 ± 1.1 h, length of hospitalization was 3.6 ± 1.2 days, and complication rate was 6.60%. The average hospitalization expenses of the FE group and IE group, respectively, were 32,069 ± 1086 RMB and 22,665 ± 899 RMB. There were significant differences in the surgical duration and hospitalization expenses (P < 0.01), but no differences between the two groups in postoperative bed rest time, length of hospitalization, or complication rates (P > 0.05). The postoperative Oswestry disability index and VAS were clearly improved in both groups compared with those of preoperation (P < 0.01). These two procedures have the same clinical outcomes (P > 0.05).

Conclusions

Both the full endoscopy technique and intermittent endoscopy technique achieved good outcomes, whereas the intermittent endoscopy technique is a more effective option for a shorter duration surgery and lower hospitalization expenses.

The morphology and clinical significance of the intraforaminal ligaments at the L5-S1 levels

BACKGROUND CONTEXT

The extraforaminal ligaments between the L5 and S1 lumbar spinal nerves and the tissues surrounding the intervertebral foramina have been well studied. However, little research has been undertaken to describe the local anatomy of the intraforaminal portion of the L5-S1 spine and detailed anatomical studies of the intraforaminal ligaments (IFLs) of the L5-S1 have not been performed.

PURPOSE

The objective of this study was to identify and describe the IFLs in relation to the L5-S1 intervertebral foramen (IVF) and to determine their clinical significance.

STUDY DESIGN

A dissection-based study of five embalmed and five fresh-frozen human cadavers was carried out.

METHODS

Twenty L5-S1 intervertebral foramina from five embalmed cadavers and five fresh cadavers were studied, and the IFLs were identified. The quantity, morphology, origin, insertion, and spatial orientation of the IFLs in the L5-S1 region were observed. The length, width, diameter, and thickness of the ligaments were measured with a vernier caliper. This study has been supported by grants from the National Natural Science Foundation of China (Grant No. 31271286) without potential conflict of interest-associated biases in the text of the paper.

RESULTS

The IFLs could be found from the entrance zone (inside) to the exit zone (outside) of the L5-S1 IVF. These ligaments were found to be of two types: a radiating ligament, which connected the nerve root sleeves that radiated to the transverse processes and wall of the IVF, and a transforaminal ligament, which connected the structures around the IVF. In our study, the radiating ligaments were found more often than the transforaminal ligaments.

CONCLUSIONS

The results demonstrate that IFLs are common structures in the IVF and that there are two types of IFLs: the transforaminal ligaments and the radiating ligaments. Transforaminal ligaments may be the potential cause of back pain. The radiating ligaments may contribute to dura laceration and epidural hemorrhage during endoscopic spinal adhesiolysis through the sacral hiatus, and an appreciation of this relationship might help reduce the risk of such complications.

The projection of nerve roots on the posterior aspect of spine from T11 to L5: a cadaver and radiological study

STUDY DESIGN

A cadaver and radiological study.

OBJECTIVE

To investigate the projection of nerve roots on the posterior aspect of the spine from T11 to L5.

SUMMARY OF BACKGROUND DATA

Understanding the projection of nerve roots on the posterior lamina will help to determine the decompressing areas of lamina and avoiding unnecessary bony resection. It can prevent segmental instability and postoperative scar formation. No studies regarding this subject are available.

METHODS

Fifteen formalin-preserved spine specimens were used for this study. After exposing the dural sac and bilateral nerve roots, small pieces of stainless steel wires were placed along the root sleeves from their points of origin, and then standard anteroposterior and lateral radiographs were taken. Parameters were measured directly on radiographs using the picture archiving communication system. Measurements included: (1) take-off angles of the nerve roots at the coronal (CA) and sagittal planes (SA); (2) distance from the origin of the root sleeve to the posterior midline (DM); (3) distance from the origin of the root sleeve to the superior (DS) and inferior margin (DI) of its corresponding lamina; and (4) distance between the origins of neighboring nerve roots (DR).

RESULTS

The CA statistically decreased from T11 (52.4° ± 3.13°) to L5 (25.8° ± 3.10°). An opposite variation tendency was observed in SA. The DS increased from 1.8 ± 0.32 mm for T11 to 5.84 ± 1.05 mm for L5. No consistent change was found at DI. The DR was largest at the L1-L2 interval (33.9 ± 1.40 mm) and it decreased progressively to L4-L5 (25.5 ± 2.40 mm). DM statistically increased from T11 (8.9 ± 1.51 mm) to L1 (10.9 ± 1.11 mm) and then progressively decreased until it reached a minimum at L5 (8.1 ± 0.83 mm).

CONCLUSION

The precise projection of nerve roots to the posterior aspect of spine and intraspinal take-off angles at the sagittal plane have been presented. Surgical interventions of the lumbar disc and nerve root may benefit from this quantitative anatomical study.

Endoscopic discectomy of L5-S1 disc herniation via an interlaminar approach: Prospective controlled study under local and general anesthesia

Background:

Open discectomy remains the standard method for treatment of lumbar disc herniation, but can traumatize spinal structure and leaves symptomatic epidural scarring in more than 10% of cases. The usual transforaminal approach may be associated with difficulty reaching the epidural space due to anatomical peculiarities at the L5–S1 level. The endoscopic interlaminar approach can provide a direct pathway for decompression of disc herniation at the L5–S1 level. This study aimed to evaluate the clinical results of endoscopic interlaminar lumbar discectomy at the L5–S1 level and compare the technique feasibility, safety, and efficacy under local and general anesthesia (LA and GA, respectively).

Methods:

One hundred twenty-three patients with L5–S1 disc herniation underwent endoscopic interlaminar lumbar discectomy from October 2006 to June 2009 by two spine surgeons using different anesthesia preferences in two medical centers. Visual analog scale (VAS) scores for back pain and leg pain and Oswestry Disability Index (ODI) sores were recorded preoperatively, and at 3, 6, and 12 months postoperatively. Results were compared to evaluate the technique feasibility, safety, and efficacy under LA and GA.

Results:

VAS scores for back pain and leg pain and ODI revealed statistically significant improvement when they were compared with preoperative values. Mean hospital stay was statistically shorter in the LA group. Complications included one case of dural tear with rootlet injury and three cases of recurrence within 1 month who subsequently required open surgery or endoscopic interlaminar lumbar discectomy. There were no medical or infectious complications in either group.

Conclusion:

Disc herniation at the L5–S1 level can be adequately treated endoscopically with an interlaminar approach. GA and LA are both effective for this procedure. However, LA is better than GA in our opinion.

Percutaneous endoscopic interlaminar discectomy for intracanalicular disc herniations at L5-S1 using a rigid working channel endoscope

OBJECTIVE

Percutaneous endoscopic transforaminal discectomy is often used as a minimally invasive procedure for lumbar disc herniation. However, a transforaminal approach posts limitations at the L5-S1 level owing to anatomic constraints, such as a high iliac crest or small intervertebral foramen and especially for migrated large intracanalicular disc herniations. We discuss the procedure and clinical results of percutaneous endoscopic interlaminar discectomy using a rigid working channel endoscope at the L5-S1 level and the relevant surgical anatomy.

METHODS

We performed percutaneous endoscopic discectomy through the interlaminar approach in 67 patients who satisfied our inclusion criteria during the period from March 2002 to November 2002. All procedures were performed under local anesthesia. Under fluoroscopic guidance, we performed discography using indigocarmine mixed with radio-opaque dye. The 6-mm working channel endoscope was then introduced into the epidural space. Herniated disc material was removed using forceps and laser under clear endoscopic visualization. We retrospectively evaluated the 65 cases with more than 1.5 years of follow-up. The patients were evaluated using the visual analogue scale (VAS) and the Oswestry Disability Index (ODI).

RESULTS

VAS for leg pain (preoperative mean, 7.89; postoperative mean, 1.58) and ODI (preoperative mean, 57.43; postoperative mean, 11.52) showed statistically significant (P = 0.00) improvement in their values at the last follow-up examination compared with preoperative scores. Of the study group, 90.8% individuals showed favorable result. The mean hospital stay was 12 hours. The average time to return to work was 6.79 weeks. Complications included two cases of dural injury with cerebrospinal fluid leakage, nine cases of dysesthesia that were transient, and one case of recurrence. Two patients required conversion to open procedure at the initial operation. There was no evidence of infection in any patients.

CONCLUSION

Percutaneous endoscopic interlaminar discectomy is a safe, effective, and minimally invasive procedure for the treatment of intracanalicular disc herniations at the L5-S1 level in properly selected cases, especially when the transforaminal approach is not possible because of anatomic constraints.