Long-term follow up of patients surgically treated by the far-lateral approach for foraminal and extraforaminal lumbar disc herniations

Full-endoscopic trans-pars interarticularis approach for far lateral lumbar discectomy

PURPOSE

Surgical management of far lateral disc herniations remains challenging. Current transforaminal full-endoscopic approaches require non-visualized docking in the Kambin's triangle and have been associated with significant risk of inadvertent nerve injury. We develop a full-endoscopic approach based on reliable bony landmarks allowing for visualization of the exiting nerve root prior to the far lateral discectomy.

METHODS

The surgical details of a full-endoscopic trans-pars interarticularis approach for far lateral discectomy are described. These descriptions include high quality intraoperative images and important surgical pearls. A small patient cohort is presented to demonstrate feasibility and safety of the procedure.

RESULTS

We demonstrate the feasibility of this approach in 14 patients with a mean age of 59.5 ± 14.7 years. At a mean follow up of 21.9 ± 6.8 months, improvement of the visual analogue scale (VAS) for leg pain was 4.3 ± 1.0 resulting in minimally clinically important difference in 78.6% of the patients. The mean improvement in VAS for the back pain was 2.6 ± 0.8 and for Oswestry disability index (ODI) was 20.6 ± 5.3. Nuances of the trans-pars surgical techniques are presented in a patient with a right-sided L4-5 far lateral disc herniation. Preoperative imaging studies, steps of the surgical progression, and intraoperative views are described in detail.

CONCLUSION

Using the pars interarticularis as the bony target area allows for safe visualized access to the extraforaminal compartment of the exiting nerve root. This novel surgical technique has the potential benefit of decreasing inadvertent neural injury and subsequent postoperative dysesthesias.

Long-term follow-up results of surgically treated patients with foraminal and far lateral disc herniations

PURPOSE

Foraminal and far lateral disc herniations are rarer cause of nerve root compression. There are reports regarding the outcome, however long-term follow-up results of surgically treated patients are few. The purpose of this retrospective study is to analyze the clinical characteristics and long-term surgical outcomes of the foraminal and far lateral disc herniations.

MATERIALS AND METHODS

The 114 patients who underwent an operation for foraminal and far lateral disc herniaitions were reviewed. Visual analogue scale of back and leg pain, the ocurrence of motor deficit and sensory dysesthesia before and after operations were used to compare the results of early and long-term outcome.

RESULTS

A total of 114 telephone interviews were conducted. The mean follow up was 134 months. Complete relief of symptoms were reported by 77 patients (67.1%). The average VAS of radicular leg pain was 7.5 Post-operatively the average VAS of radicular pain decreased to 2.2. Preoperatively, 9 patients (7.6%) had motor deficit and 17 (14.4%) patients had sensory dysesthesia. Post-operatively 9 (100%) of the patients showed motor, and 12 (70.6%) of the patients showed sensory improvement. In 17 patients with hypoesthesia the complaints continued during 2 weeks to 6 months. They were given gabapentin as medical treatment, however 5 of these patients still have sensory dysesthesia. The outcome was: 67.1% excellent (77 patients), 26.3% good (30 patients), 6.1% fair (7 patients).

CONCLUSION

The far lateral approach is a minimally invasive and safe procedure with low complication rates.

A transfacet approach to the lumbar nerve root canal: technical note

BACKGROUND

Intraforaminal and extraforaminal nerve root compressions caused by disk herniation or stenosis are relatively common causes of lumbar radiculopathy. Currently, the two available surgical treatment methods are decompression from the spinal canal or lateral decompression via the Wiltse approach.

OBJECTIVE

To describe a novel transosseous approach to the lumbar nerve root canal.

METHODS

Transfacet foraminotomy was performed in 11 patients with intraforaminal or extraforaminal disk herniation. The outcome was measured using the Patient Satisfaction Index (PSI), need for reoperation, radiographic criteria, and finite element analysis.

RESULTS

We noted that at the time of dismissal, PSI scores of 1 and 3 were reported by 10 and one patients, respectively. At the last follow-up, 10 patients reported a PSI score of 1 or 2. Two patients required reoperation because of recurrent disk herniation. Two patients underwent computed tomography (CT) postoperatively, which showed the transfacet approach. Intriguingly, a second postoperative CT after one month showed that the hole through the facet joint had shrunk significantly.

CONCLUSION

A posterior-anterior transfacet approach for intraforaminal or extraforaminal disk herniations using an ellipsoid facetectomy is safe and allows for fast and comfortable decompression of the nerve root without compromising the long-term strength of the facet joint.

The irony of the transforaminal approach: A comparative cohort study of transforaminal endoscopic lumbar discectomy for foraminal versus paramedian lumbar disc herniation

Transforaminal endoscopic lumbar discectomy (TELD) is useful for soft lumbar disc herniation (LDH). Although the transforaminal approach can reach the foraminal disc zone, the risk of exiting nerve root irritation along the path is considerable. Few studies have assessed the difficulties of TELD for foraminal LDH. The objective of this study is to compare the clinical results of TELD between foraminal or far-lateral LDH and paramedian LDH.Between June 2016 and July 2017, 135 consecutive patients with single-level LDH were treated with TELD for 2 years. Among them, 25 patients had foraminal or far-lateral LDH (foraminal group), and the remaining 110 patients had central or subarticular LDH (paramedian group). Perioperative data and clinical outcomes were evaluated using the visual analog pain scale, Oswestry Disability Index, and modified Macnab criteria.The foraminal group showed a higher rate of significant access pain (24.00% vs 8.19%, P < .05). The foraminal group also had a longer duration of surgery, length of hospital stay, and return to work (all P < .05). Pain scores and functional status were significantly improved in both groups. Although there were no differences in the outcomes at 2 years postoperatively, early pain and disability at 6 weeks were higher in the foraminal group.Ironically, the early clinical results of TELD for foraminal LDH may be less favorable than those for paramedian LDH. Therefore, great care should be taken during TELD for foraminal or far-lateral LDH.

Minimally Invasive Far-Lateral Microdiscectomy: A New Retractor for Far-Lateral Lumbar Disc Surgery

Background

To date, a number of approaches have been described for far-lateral disc surgery, including midline, paramedian, and intertransverse approaches. These approaches pose challenges for surgeons due to the difficulty in retraction caused by the anatomy of the foramen. We designed a retractor suitable for the three-dimensional anatomical structure of the foramen. In this study, we aimed to evaluate the surgical outcomes of the patients who were operated on using this retractor in our clinic.

Methods 

The retrospective study included patients who were operated on due to far-lateral disc herniation using the retractor designed in our clinic between February 2013 and December 2018.

Results 

The study included 11 (64.7%) women and 6 (35.3%) men, with a mean age of 56 years (range: 42-70 years). The mean operative time was 49 minutes (range: 40-70 minutes), the mean estimated blood loss was 42 mL (range: 25-60 mL), and the mean follow-up period was 22.6 months (range: 13-48 months). No complication occurred in any patient. A minimally invasive discectomy was performed via the paramedian approach in each patient. The patients were evaluated using the visual analog scale (VAS) for radicular pain, Oswestry Disability Index (ODI), 36-Item Short Form Survey (SF-36), and the modified MacNab criteria.

Conclusion 

The retractor developed in our study provided numerous benefits during the surgical procedure as it led to minimal blood loss and reduced operative times by avoiding bone resection in extraforaminal discs and requiring minimal bone resection in foraminal discs.

Posterolateral Transforaminal Full-Endoscopic Lumbar Discectomy for Foraminal or Extraforaminal Lumbar Disc Herniations

BACKGROUND

Surgical procedures via the posterior median or paramedian approach for lateral lumbar disc herniation require significant bone resection to reach the herniation. In contrast, posterolateral transforaminal full-endoscopic lumbar discectomy (FELD) allows direct access to the lateral disc herniation. This study aimed to determine the efficacy and safety of this procedure.

METHODS

A total of 118 patients who underwent posterolateral transforaminal FELD were retrospectively examined. Data on surgical time, perioperative complications, and reoperation rate were reviewed from the medical records. Clinical evaluations were completed in 78 patients using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and numeric rating scale (NRS) for low back pain, lower limb pain, and lower limb numbness obtained at baseline and during a follow-up of more than 12 months.

RESULTS

The mean operative time was 33.9 min. Postoperative transient dysesthesia occurred in 11 of 118 patients (9.3%). No other complications were observed. Reoperation was performed in nine patients (5.9%). All domains of JOABPEQ and NRS significantly improved during the follow-up period. The effectiveness rates of the JOABPEQ for measuring low back pain, lumbar function, walking ability, social life function, and mental health were 70.4%, 46.5%, 62.0%, 59.2%, and 32.4%, respectively. Using the Macnab criteria, excellent or good results were achieved in 52 patients (73%).

CONCLUSIONS

Successful clinical results were obtained with a few complications and improvements in the domains of JOABPEQ and NRS. Posterolateral transforaminal FELD for lateral lumbar disc herniations is an effective and safe surgical option with minimal invasiveness and sufficient decompression.

Far-lateral Disc Herniation Treated by Lateral Lumbar Interbody Fusion without Complete Fragment Excision: A Case Report and Review of the Literature

Symptomatic far-lateral lumbar disc herniation is a less common causes of lumbar radiculopathy than paracentral or central disc herniation. Treatment of far-lateral disc herniation with a retroperitoneal, transpsoas approach and disc fragment excision has been described. However, treatment of far-lateral disc herniation using lateral lumbar interbody fusion (LLIF) without neural manipulation has not been described. We report one case in which symptom resolution was accomplished via indirect decompression with anterior column support via LLIF without disc fragment excision and review the current literature. The patient noted immediate relief of his preoperative leg pain in the recovery room and ambulation began the same day. Narcotics were effective in treating his incisional pain and mild back pain. The patient was seen two weeks postoperatively and he had stopped all narcotics. At six weeks, the patient continued to have significant improvement and was able to take hour-long walks. At five months, the patient did not have any pain and continued to have improvement in his left quadriceps strength. Minimally invasive lateral lumbar interbody fusion has allowed surgeons to provide both direct and indirect neural decompression through a retroperitoneal approach. This technique may be ideal for far-lateral disc herniation as it also allows a lateral visualization of the herniation without bony, posterior muscular, or ligamentous disruption.

Direct Tubular Lumbar Microdiscectomy for Far Lateral Disc Herniation: A Modified Approach

OBJECTIVE

The concept of minimally invasive tubular discectomy is based on precise placement of the retractor over the surgical target to minimize collateral tissue trauma. For far lateral disc herniation, the junction between the pars and the transverse process has generally been adopted as the target for facilitating early nerve root exposure; however, this may limit access to the disc space and increase the risks of iatrogenic neuralgia. An alternative approach to help address these issues involving docking the retractor caudally directly over the disc space with the aid of a microscope is here proposed. The purpose of this study was to evaluate the safety and efficacy of such an approach.

METHODS

Nineteen patients in whom the modified approach was performed over a 35-month period were identified. Direct access to the disc space was attained by directing the retractor against the lateral margin of the facet joint and following the inferior transverse process medially towards the foramen with minimal exposure of the nerve root. Clinical outcomes were assessed by the Oswestry Disability Index, visual analogue scale scores for leg and back pain, Short Form 36 physical functioning (SF36-PF) and bodily pain (SF36-BP) scores and sciatica bothersomeness and frequency indexes (SBI & SFI) and obtained from a prospective patient database. Follow-up data in the first 6 months were compared with preoperative baseline data.

RESULTS

All procedures were successfully completed with the modified approach. Contained disc herniation without sequestrated fragments was found in all but four cases. No perioperative complications or reoperation were recorded and no postoperative dysesthesia was noted. Clinically significant reductions in mean Oswestry Disability Index (32; 95% CI, 21-43) and visual analogue scale scores for leg pain (38 mm; 95% CI, 23-54 mm) and back pain (35 mm; 95% CI, 21-48 mm) scores were noted in the first 6 months. Significant improvements in SF36-PF (40; 95% CI, 30-51) and SF36-BP (35; 95% CI, 26-43), SBI (9; 95% CI, 6-11) and SFI (11; 95% CI, 8-13) were also recorded.

CONCLUSIONS

A modified direct tubular approach is safe and effective for treating far lateral lumbar disc herniation. Our early results suggest that this approach helps safeguard adequate decompression and reduce the risk of postoperative dysesthesia.

Three-Years Outcome of Microdiscectomy via Paramedian Approach for Lumbar Foraminal or Extraforaminal Disc Herniations in Elderly Patients over 65 Years Old

OBJECTIVE

Lumbar foraminal or extraforaminal disc herniations (FEFDH) have unusual clinical features and higher incidence in elderly patients compared to usual intraspinal canal disc herniations. We evaluated the efficacy of microdiscectomy via paramedian approach for lumbar FEFDH in elderly patients over the age of 65.

METHODS

Retrospective study was performed in 68 patients over the age of 65 (23 male and 45 female patients; 71.46±3.87 years) who underwent microdiscectomy via paramedian approach for unilateral lumbar FEFDH causing sciatica. The radiological factors including degree of slippage, presence of instability, disc height, and degree of disc degeneration; pain and functional status by the means of visual analogue scale score, Oswestry Disability Index score, and Macnab classification were analyzed preoperatively and during the postoperative follow-up period of 3 years to evaluate the efficacy of the surgical treatment.

RESULTS

Pain and functional status improved according to short- and long-term follow-up evaluations after surgery. Radiological changes following surgery, which can be understood as structural deteriorations and deformations, did not represent patient condition. Nine patients underwent additional surgery due to sustained or recurring leg pain of aggravation of back pain, and fusion surgery was required for 3 patients. Degree of preoperative slippage was the only statistically significant factor related to additional surgery (p<0.05).

CONCLUSION

Microdiscectomy via paramedian approach for FEFDH may be a good surgical alternative in elderly patients. Radiological changes after surgery did not show a concordance with patients' actual functional status. The excessive preoperative slippage tended to lead to unfavorable result after surgery and was associated with additional surgery.

Surgical treatment of far lateral lumbar disc herniation: a safe and simple approach

Lumbar discectomy is one of the most commonly performed neurosurgical procedure. Far lateral disc herniations (FLDH) make up a minor portion of the total discectomy workload for spine surgeons. Due to their lower incidence, as well as their different anatomical positioning compared to the more common para-median disc herniation, the surgical procedures involved in releasing the neural compression caused by FLDHs are often challenging and at times frustrating to most spine surgeons, resulting in suboptimal outcomes for the patient related to the higher risk of spinal instability from facet joint disruption and may even be associated with nerve root injury. We discuss here a safe and simple approach to tackle FLDH.

Postoperative Clinical Outcome and Risk Factors for Poor Outcome of Foraminal and Extraforaminal Lumbar Disc Herniation

OBJECTIVE

We evaluated postoperative outcomes in patients who have lumbar foraminal or extraforaminal disc herniation (FELDH) and suggested the risk factors for poor outcomes.

METHODS

A total of 234 patients were selected for this study. Pre- and post-operative Visual Analogue Scale (VAS) and Korean version Oswestry Disability Index (KODI) were evaluated and the changes of both score were calculated. Outcome was defined as excellent, good, fair, and poor based on Mcnab classification. The percentage of superior facetectomy was calculated by using the Maro-view 5.4 Picture Archiving Communication System (PACS).

RESULTS

Paramedian lumbar discectomy was performed in 180 patients and combined lumbar discectomy was performed in 54 patients. Paramedian lumbar discectomy group showed better outcome compared with combined discectomy group. p value of VAS change was 0.009 and KODI was 0.013. The average percentage of superior facetectomy was 33% (range, 0-79%) and it showed negative correlation with VAS and KODI changes (Pearson coefficient : -0.446 and -0.498, respectively). Excellent or good outcome cases (Group I) were 136 (58.1%) and fair or poor outcome cases (Group II) were 98 (41.9%). The percentage of superior facetectomy was 26.5% at Group I and 42.5% at Group II. There was significant difference in superior facetectomy percentage between Group I and II (p=0.000).

CONCLUSION

This study demonstrated that paramedian lumbar discectomy with preservation of facet joints is an effective and good procedure for FELDH. At least 60% of facet should be preserved for excellent or good outcomes.

Clinical and Radiological Characteristics of Lumbosacral Lateral Disc Herniation in Comparison With Those of Medial Disc Herniation

Lateral disc herniation (foraminal and extra foraminal) has clinical characteristics that are different from those of medial disc herniation (central and subarticular), including older age, more frequent radicular pain, and neurologic deficits. This is supposedly because lateral disc herniation mechanically irritates or compresses the exiting nerve root or dorsal root ganglion inside of a narrow canal more directly than medial disc herniation. The purpose of this study was to investigate clinical and radiological characteristics of lateral disc herniation in comparison with medial disc herniation. The 352 subjects diagnosed with localized lumbosacral disc herniation and followed up for at least 12 months after completion of treatment were included and divided into medial and lateral disc herniation groups, according to the anatomical location of the herniated disc in axial plain of magnetic resonance image. Clinical and radiological data were obtained and compared between the two groups. The lateral group included 74 (21%) patients and the medial group included 278 (79%). Mean age of the lateral group was significantly higher than that in the medial group. The lateral group showed a significantly larger proportion of patients with radiating leg pain and multiple levels of disc herniations than the medial group. No significant differences were found in terms of gender, duration of pain, pretreatment numeric rating scale, severity of disc herniation (protrusion and extrusion), and presence of weakness in leg muscles. The proportion of patients who underwent surgery was not significantly different between the 2 groups. However, the proportion of patients who accomplished successful pain reduction after treatment was significantly smaller in the lateral than in the medial group. In conclusion, patients with lateral disc herniation were older and had larger proportion of radiating leg pain than those with medial disc herniation. Lateral disc herniation was more associated with multiple disc herniations and worse clinical outcomes after treatment than medial disc herniation.

The Comparisons of Surgical Outcomes and Clinical Characteristics between the Far Lateral Lumbar Disc Herniations and the Paramedian Lumbar Disc Herniations

Objective

The purpose of this study is to analyze clinical characteristics and surgical outcomes of the far lateral and the paramedian disc herniations.

Methods

The 88 patients who underwent an operation for lumbar disc herniations were reviewed. Visual analogue scale of leg and back pain, occurrence of sensory dysesthesia and motor deficit before and after operations were used to compare the far lateral with the paramedian disc herniations.

Results

Statistically, the far lateral herniations had more severe radicular leg pain and showed more frequent occurrence of sensory dysesthesia than paramedian herniations before operation (p<0.05). In the far lateral herniation group, preoperatively, 15 patients (75%) had sensory dysesthesia and among them, 4 patients (27%) showed improvement. In the paramedian herniation group, preoperatively, 25 patients (37%) had sensory dysesthesia and among them, 21 patients (84%) showed improvement. The degree of improvement in sensory dysesthesia was statistically higher in paramedian herniation group (p<0.05). In the far lateral herniation group, preoperatively, 11 patients (55%) had motor deficit and among them, 10 patients (91%) showed improvement. In the paramedian herniations, preoperatively, 29 patients (43%) had motor deficit and among them, 25 patients (86%) showed improvement. The degree of improvement in motor deficit was not statistically significant between groups (p>0.05).

Conclusion

Preoperatively, the far lateral herniations had more severe radicular leg pain and frequent occurrence of sensory dysesthesia. Postoperatively, the sensory dysesthesia was less improved and back pain was more severe in the far lateral herniations.

Clinical outcomes of percutaneous endoscopic surgery for lumbar discal cyst

OBJECTIVE

Discal cyst is rare and causes indistinguishable symptoms from lumbar disc herniation. The clinical manifestations and pathological features of discal cyst have not yet been completely known. Discal cyst has been treated with surgery or with direct intervention such as computed tomography (CT) guided aspiration and steroid injection. The purpose of this study is to evaluate the safety and efficacy of the percutaneous endoscopic surgery for lumbar discal cyst over at least 6 months follow-up.

METHODS

All 8 cases of discal cyst with radiculopathy were treated by percutaneous endoscopic surgery by transforaminal approach. The involved levels include L5-S1 in 1 patient, L3-4 in 2, and L4-5 in 5. The preoperative magnetic resonance imaging and 3-dimensional CT with discogram images in all cases showed a connection between the cyst and the involved intervertebral disc. Over a 6-months period, self-reported measures were assessed using an outcome questionaire that incorporated total back-related medical resource utilization and improvement of leg pain [visual analogue scale (VAS) and Macnab's criteria].

RESULTS

All 8 patients underwent endoscopic excision of the cyst with additional partial discectomy. Seven patients obtained immediate relief of symptoms after removal of the cyst by endoscopic approach. There were no recurrent lesions during follow-up period. The mean preoperative VAS for leg pain was 8.25±0.5. At the last examination followed longer than 6 month, the mean VAS for leg pain was 2.25±2.21. According to MacNab' criteria, 4 patients (50%) had excellent results, 3 patients (37.5%) had good results; thus, satisfactory results were achieved in 7 patients (87.5%). However, one case had unsatisfactory result with persistent leg pain and another paresthesia.

CONCLUSION

The radicular symptoms were remarkably improved in most patients immediately after percutaneous endoscopic cystectomy by transforaminal approach.

Ultra-long-term outcome of surgically treated far-lateral, extraforaminal lumbar disc herniations: a single-center series

PURPOSE

Far-lateral extraforaminal lumbar disc herniation is an uncommon cause of nerve root entrapment, and studies addressing the long-term outcome of surgically treated patients are few. The purpose of this study was to analyze the ultra-long-term outcome of patients who were treated via a lateral approach.

METHODS

The medical reports of 138 consecutive patients were analyzed with regard to signs and symptoms, operative findings, complications, and short-term outcome (6 weeks). To assess long-term results, standardized telephone interviews were performed using a structured questionnaire. The patients were questioned about pain using the verbal rating scale and persisting symptoms, if any. Other queries were related to the Oswestry Disability Index. Subjective satisfaction with the result of surgery was classified as excellent (no pain), good (some pain), fair (moderate pain), and poor (unchanged or worse) based on MacNab classification.

RESULTS

At short-term follow-up, major and moderate leg pain had decreased from 99.3 to 5.1% and low back pain from 97.8 to 2.8%. Sensory and motor deficits, however, were still present in the majority of patients. A total of 87 telephone interviews were conducted, and the mean follow-up was 146 months. As many as 49 patients (56.3%) reported complete relief of symptoms, 14 patients (16.1%) had minor ailments under physical stress, and 24 patients (27.6%) had permanent residual symptoms. The most common complaint was remaining sensory disturbance. Despite residual symptoms, the vast majority of patients expressed satisfaction with the result of surgery. The outcome was subjectively rated as follows: 75.9% excellent (66 patients), 18.4% good (16 patients), 4.6% fair (4 patients), and 1.1% poor (1 patient).

CONCLUSIONS

The lateral approach is a minimally invasive and safe procedure with low complication rates. The profit from surgery is maintained beyond the usual postoperative observation periods. Thus, ultimate outcome at ultra-long-term follow-up is very gratifying in the vast majority of patients.

Minimally invasive approach to far lateral lumbar disc herniation: technique and clinical results

BACKGROUND

To describe our minimally invasive technique for the surgical treatment of far lateral lumbar disc herniation (FLLDH) using MetRx tissue dilators system and a surgical microscope; and to report our experience with this method.

METHODS

Retrospective analysis of data of all patients with FLLDH treated by minimally invasive discectomy. Outcome assessment was performed using neurological status, the visual analog scale (VAS) for back pain and leg pain, and the Short Form-36 Health Survey Questionaire (SF-36).

RESULTS

Thirty-one patients were included in this study. The mean follow-up time was 25.16 months. Muscle weakness improved in all patients. Sensory deficits disappeared in 22 patients and improved in the other five patients. The mean VAS for radicular pain showed significant improvement from 8.6 preoperatively, to 3.8 in the immediate postoperative period (P-value <.01), and 0.6 at the last follow-up. The mean VAS for back pain also showed significant improvement from 5.8 preoperatively, to 4.8 in the immediate postoperative period and 0.7 at the last follow-up visit. The SF 36 data showed significant improvement in all the eight domains: the physical functioning improved from 9.68 preoperatively to 76.33 at 6-month follow-up and SF 36 bodily pain index improved from 6.71 before surgery to 79.53 at 6-month follow up. Complications included two cases of incidental dural tear, without postoperative CSF leakage and one case of residual sequestered disc that was successfully removed by a second minimally invasive procedure.

CONCLUSION

Our results suggest that this minimally invasive technique is safe and efficacious for the management of FLLDH and might be an alternative to open microsurgical approaches.

Contralateral approach for far lateral lumbar disc herniations: a modified technique and outcome analysis of nine patients

STUDY DESIGN

A retrospective analysis of 9 patients who underwent a modified surgical procedure for the treatment of far lateral lumbar disc herniations.

OBJECTIVES

To illustrate a modified technique for approaching the neural foramen from the contralateral side, minimizing muscle retraction and bone/ligament resection, and to analyze clinical results.

SUMMARY OF BACKGROUND DATA

The most commonly used surgical techniques for the removal of far lateral lumbar disc herniations are ipsilateral approaches, that require partial or complete facet resection and/or intertransverse ligament resection, which may result in vertebral instability and/or chronic back pain.

METHODS

Nine patients with intraforaminal or intra/extraforaminal lumbar disc herniation underwent surgery using a modified contralateral approach. There was unilateral muscle retraction and no medial facetectomy nor intertransverse/interspinous ligament resection. Preoperative and postoperative Oswestry functional status evaluation and complications were reviewed and Macnab's postoperative categories were assigned to evaluate the efficacy and safety of the surgery.

RESULTS

No serious complications were noted. The mean preoperative and postoperative Oswestry scores were 44 and 14 respectively (P < 0.01). Overall excellent-to-good results were 100%.

CONCLUSION

This modified contralateral approach offered a wide exposure of intervertebral foramen region and allowed to remove the herniated disc material with minimal resection of osseous and ligamentous structures. Successful results were achieved in all patients treated by this technique.

Strategies for Noncontained Lumbar Disc Herniation by an Endoscopic Approach : Transforaminal Suprapedicular Approach, Semi-Rigid Flexible Curved Probe, and 3-Dimensional Reconstruction CT with Discogram

OBJECTIVE

The purpose of this study was to evaluate the efficacy of a transforaminal suprapedicular approach, semi-rigid flexible curved probe, and 3-dimensional reconstruction computed tomography (3D-CT) with discogram in the endoscopic treatment of non-contained lumbar disc herniations.

METHODS

The subjects were 153 patients with difficult, non-contained lumbar disc herniations undergoing endoscopic treatment. The types of herniation were as follows : extraforaminal, 17 patients; foraminal, 21 patients; high grade migration, 59 patients; and high canal compromise, 56 patients. To overcome the difficulties in endoscopic treatment, the anatomic structures were analyzed by 3D reconstruction CT and the high grade disc was extracted using a semi-rigid flexible curved probe and a transforaminal suprapedicular approach.

RESULTS

The mean follow-up was 18.3 months. The mean visual analogue scale (VAS) of the patients prior to surgery was 9.48, and the mean postoperative VAS was 1.63. According to Macnab's criteria, 145 patients had excellent and good results, and thus satisfactory results were obtained in 94.77% cases.

CONCLUSION

In a posterolateral endoscopic lumbar discectomy, the difficult, non-contained disc is considered to be the most important factor impeding the success of surgery. By applying a semi-rigid flexible curved probe and using a transforaminal suprapedicular approach, good surgical results can be obtained, even in high grade, non-contained disc herniations.

Minimally invasive approach to extraforaminal disc herniations at the lumbosacral junction using an operating microscope: case series and review of the literature

Surgical access to extraforaminal lumbar disc herniations is complicated due to the unique anatomical constraints of the region. Minimizing complications during microdiscectomies at the level of L5–S1 in particular remains a challenge. The authors report on a small series of patients and provide a video presentation of a minimally invasive approach to L5–S1 extraforaminal lumbar disc herniations utilizing a tubular retractor with microscopic visualization.

Microdecompression for extraforaminal L5-s1 disc herniation; the significance of concomitant foraminal disc herniation for postoperative leg pain

OBJECTIVE

To analyze the relationship of concomitant foraminal lumbar disc herniation (FLDH) with postoperative leg pain after microdecompression for extraforaminal lumbar disc herniation (EFLDH) at the L5-S1 level.

METHODS

Sixty-five patients who underwent microdecompression for symptomatic EFLDH at the L5-S1 level were enrolled. According to the severity of accompanying FLDH, EFLDH was classified into four categories (Class I : no FLDH; Class II : mild to moderate FLDH confined within a lateral foraminal zone; Class III : severe FLDH extending to a medial foraminal zone; Class IV : Class III with intracanalicular disc herniation). The incidence of postoperative leg pain, dysesthesia, analgesic medication, epidural block, and requirement for revision surgery due to leg pain were evaluated and compared at three months after initial surgery.

RESULTS

The incidences of postoperative leg pain and dysesthesia were 36.9% and 26.1%, respectively. Pain medication and epidural block was performed on 40% and 41.5%, respectively. Revision surgery was recommended in six patients (9.2%) due to persistent leg pain. The incidences of leg pain, dysesthesia, and requirement for epidural block were higher in Class III/IV, compared with Class I/II. The incidence of requirement for analgesic medication was significantly higher in Class III/IV, compared with Class I/II (p=0.02, odds ratio=9.82). All patients who required revision surgery due to persistent leg pain were included in Class III/IV.

CONCLUSION

Concomitant FLDH seems related to postoperative residual leg pain after microdecompression for EFLDH at the L5-S1 level.

Percutaneous endoscopic discectomy for extraforaminal lumbar disc herniations: extraforaminal targeted fragmentectomy technique using working channel endoscope

STUDY DESIGN

A retrospective analysis of 41 patients operated for excision of soft lumbar extraforaminal disc herniation (EFDH) by percutaneous endoscopic extraforaminal approach under local anesthesia by a new technique.

OBJECTIVES

To describe a new and safer percutaneous endoscopic technique for the removal of soft EFDH and report the results on the basis of a new objective criterion modified from Oswestry Disability Index (ODI).

SUMMARY OF BACKGROUND DATA

EFDHs usually occur in older patients and present with atypical symptoms. Their diagnosis and treatment are still controversial, with various authors describing open midline or paraspinal approaches using the microscope with varying amounts of success. Percutaneous endoscopic techniques have traditionally been considered unsuitable for these herniations.

METHODS

Forty-one patients with a soft EFDH were subjected to percutaneous endoscopic discectomy with the new technique. In our technique, the skin entry point is medial and the angle of approach steeper as compared with the earlier described endoscopic techniques. This might help in avoiding exiting root injury and increasing the efficacy of the procedure. The results were analyzed on the basis of percentage change in ODI as compared with preoperative values.

RESULTS

Mean follow-up was 34.1 month. Mean VAS score for radicular pain improved from 8.6 to 1.9, and mean ODI improved from 66.3 to 11.5. Overall, 92% of patients experienced satisfactory outcome. Two patients had poor outcome due to the need for subsequent open surgery.

CONCLUSION

Percutaneous endoscopic discectomy using the "extraforaminal targeted fragmentectomy" technique is an effective and safe procedure for the select group of patients with a soft EFDH.

Transforaminal Percutaneous Endoscopic Discectomy in the Treatment of Foraminal and Extraforaminal Lumbar Disc Herniations

The objective of this study is to evaluate the efficacy of the endoscopic technique, as applied to patients with foraminal and extraforaminal disc herniations, and to report the outcome and complications. A retrospective analysis was performed of 35 consecutive cases of foraminal and extraforaminal lumbar disc herniation managed by posterolateral endoscopic discectomy. Pain was measured by means of the Visual Analog Score. Patient satisfaction was evaluated by the Macnab outcome criteria. The median follow-up period was 18 months (range 10 to 35 months). The mean Visual Analog Score improved from 8.6 before the surgery to 3.2 after the surgery. Overall, excellent or good outcomes were obtained in 30 (85.7%) of the 35 patients at the last follow-up examination, with both these outcomes showing statistically significant improvement (P<0.01). There were no complications related to the surgery, nor was any spinal instability detected. Three patients (8.6%) experienced persistent radiculopathy and subsequently underwent open microdiscectomy at the same level. We concluded that transforaminal percutaneous endoscopic discectomy is safe and efficacious in the treatment of foraminal or extraforaminal disc herniations. However, proper patient selection is paramount to ensure a satisfactory outcome after decompression of foraminal and extraforaminal disc herniations.

Lateral transmuscular or combined interlaminar/paraisthmic approach to lateral lumbar disc herniation? A comparative clinical series of 48 patients

BACKGROUND

The optimum operative technique for lateral lumbar disc herniations (LLDH) remains unclear, and both interlaminar and extraspinal approaches are used.

OBJECTIVE

To compare outcome after LLDH removal either by a lateral transmuscular approach (LTM) or by a combined interlaminar and paraisthmic approach (CIP).

METHODS

28 patients underwent surgery using CIP and 20 using LTM. All patients were operated on by the same neurosurgeon. The clinical presentation of the two groups was comparable. Overall outcome was assessed after a mean follow up period of between 19 and 37 months using the Ebeling classification. In addition, the effect of surgery on radicular pain, low back pain, and sensory and motor deficits was defined.

RESULTS

Excellent to good results were achieved in 95% of the LTM group and 57% of the CIP group. The outcome was satisfactory to poor in 5% of the LTM and 43% of the CIP group (p<0.004). The percentage of sensorimotor deficit and of radicular pain improvement was higher in the LTM group. New low back pain was found exclusively in the CIP group (21%). The complication rate was 5% in the LTM group and 11% in the CIP group.

CONCLUSIONS

The LTM approach achieves a better overall outcome and improvement in radiculopathy. The complication rate is lower with the transmuscular route and the risk of new low back pain is minimised. These results are likely to be attributable at least in part to the lesser invasiveness of the LTM approach.

Paraspinal approach to the far lateral disc herniations: retrospective study on 42 cases

Forty-two patients underwent surgery for far-lateral disc herniations. Average patient age was 45.1 years, 28 patients were male and 14 female. The level concerned most was L4-5 disc (55%). A paramedian muscle-splitting intertransverse approach is described for this type of disc herniation. This method allows direct visualization of the disc and root involved and does not provide bone resection and important surgical manipulation. Ninety-one percent of the patients reported excellent or good results according to Macnab outcome criteria with an average follow-up of 32.5 months (range 1-5 years). Twelve patients (28.6%) developed postoperative transient radicular pain that disappeared in 15-21 days after analgesic therapy. There were no recurrences or spinal instability. The paramedian muscle-splitting intertransverse approach is a rational technique. Its advantages are that the spine is not opened and spinal stability is maintained. It requires minimal soft-tissue and bone resection and the herniated disc is directly visualized. Moreover, it contains minimal manipulation of the neuro-vascular structures and avoids significant muscle retraction. However, it requires an adequate learning curve and good familiarity with microsurgical techniques.

Effect of facetectomy on lumbar spinal stability under sagittal plane loadings

STUDY DESIGN

A study using an anatomically accurate finite-element model of a L2-L3 motion segment to investigate the biomechanical effects of graded bilateral and unilateral facetectomies of L3 under flexion and extension loadings.

OBJECTIVE

To predict the amount of facetectomy on lumbar motion segment that would cause segmental instability, therefore enhancing the understanding concerning the role of the facet under sagittal loadings.

SUMMARY OF BACKGROUND DATA

This study provides a quantitative study on the role of facets in preserving segmental lumbar stability. Previous analytical models lack of three-dimensional structural characterization and insufficient element representation for facet joints.

METHODS

A validated finite-element L2-L3 model was subjected to sagittal loadings at 7.5 Nm. Effects of ligaments and facets were examined to establish their relative importance on segment response. The effect of iatrogenic changes (graded unilateral and bilateral facetectomy) was then investigated under these loadings to predict the alterations in terms of gross external (angular and coupled) responses, flexibilities, and facet load.

RESULTS

This study shows the importance of preserving ligaments to prevent rotational instabilities for motion segment under flexion. The effect of the facetectomy on the motion segment is insignificant under flexion. In extension, unilateral facetectomy and resection on contralateral facet markedly alters the rotational motion and flexibilities as well as coupled motions. Also, unilateral complete facetectomy with resection of less than 100% on contralateral facet generates high facet load.

CONCLUSIONS

Clinically, this study suggests that it may be appropriate to incorporate additional stabilization procedure in restoring the spinal strength and stability for surgical intervention of unilateral complete facetectomy and resection on contralateral facet. The exploitation of the finite-element method to simulate clinically related situations permits an improved understanding of lumbar spinal stability to assist in defining clinical expectation for various forms of surgical intervention of the operative procedures.

Combined transarticular lateral and medial approach with partial facetectomy for lumbar foraminal stenosis. Technical note

The authors performed a microsurgical combined transarticular lateral and medial procedure with partial facetectomy in 24 patients (16 men and nine women) with lumbar intervertebral foraminal stenosis to decompress the affected nerve root. The goal of this surgery was to maintain the integrity of the facet joint, to guarantee satisfactory exploration, and to obtain a sufficient decompression of the intervertebral foramen. Because only minimal bone resection is required, the risk of secondary instability induced by complete facetectomy is avoided. The clinical results of this procedure were excellent in the majority of cases. The mean follow-up period was 21.8 months.