Minimally Invasive Far Lateral Lumbar Discectomy With Modified Technique: Symptomatic Relief and Intersegmental Stability Study.

OBJECTIVE: To evaluate the use of a modified minimally invasive surgery (MIS) technique for far lateral lumbar discectomy (FLDH) that minimizes the degree of bony drilling required for nerve root decompression, increasing postoperative pain reduction rate with reduced risk of iatrogenic spinal instability. SUMMARY OF BACKGROUND DATA: FLDH accounts for approximately 10% of all lumbar disc herniations and is increasingly recognized in the era of advanced imaging techniques. These disc herniations typically result in extra-foraminal nerve root compression. Minimally invasive spine techniques are increasingly performed with various degrees of foraminal and facet removal to decompress the affected nerve root. METHODS: The study design involves a single institutional, retrospective cohort technical review. The review was completed of all patients undergoing MIS far lateral lumbar discectomy between 2010 and 2020. Cross-sectional, summary statistics were calculated for all variables. Counts and percentages were recorded for categorical variables and mean and standard deviations were calculated for continuous variables. RESULTS: A total of 48 patients underwent MIS far lateral lumbar discectomies (FLLD) from 2010 to 2020. The mean age was 63 ± 11.5 years (60.4% males), the mean BMI was 28.5 ± 5.5, and 20.8% smokers. The most common presenting complaint was both low back and radicular pain (79.2%) with 8.3% of patients suffering from motor weakness preoperatively. The mean follow-up time was 4.3 ± 2.7. The mean length of stay was 1.3 ± 1.4 days with 77.1% of patients discharged postoperative day one. Forty-three patients (93.5%) had improvement in their symptoms. Twenty-seven (58.7%) had complete resolution in 2.6 months on average. Six patients (13%) had immediate symptom resolution postoperatively. CONCLUSIONS: Our modified technique for FLLD allows MIS access to the extra-foraminal site of nerve root compression without the need for bony drilling. This minimizes postoperative pain and reduces the risk of iatrogenic spinal instability without sacrificing symptom resolution.

Upper lumbar spine far lateral disc herniations masquerading as peripheral nerve sheath tumors: illustrative cases.

BACKGROUND: Migratory disc herniations can mimic neoplasms clinically and on imaging. Far lateral lumbar disc herniations usually compress the exiting nerve root and can be challenging to distinguish from a nerve sheath tumor due to the proximity of the nerve and characteristics on magnetic resonance imaging (MRI). These lesions can occasionally present in the upper lumbar spine region at the L1-2 and L2-3 levels. OBSERVATIONS: The authors describe 2 extraforaminal lesions in the far lateral space at the L1-2 and L2-3 levels, respectively. On MRI, both lesions tracked along the corresponding exiting nerve roots with avid postcontrast rim enhancement and edema in the adjacent muscle tissue. Thus, they were initially concerning for peripheral nerve sheath tumors. One patient underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) screening and demonstrated moderate FDG uptake on PET-CT scan. In both cases, intraoperative and postoperative pathology revealed fibrocartilage disc fragments. LESSONS: Differential diagnosis for lumbar far lateral lesions that are peripherally enhancing on MRI should include migratory disc herniation, regardless of the level of the disc herniations. Accurate preoperative diagnosis can aid in decision making for management, surgical approach, and resection.

Postoperative Outcomes and Resource Utilization Following Open vs Endoscopic Far Lateral Lumbar Discectomy.

BACKGROUND: Operative approaches for far lateral disc herniation (FLDH) repair may be classified as open or minimally invasive. The present study aims to compare postoperative outcomes and resource utilization between patients undergoing open and endoscopic (one such minimally invasive approach) FLDH surgeries. METHODS: A total of 144 consecutive adult patients undergoing FLDH repair at a single, university health system over an 8-year period (2013-2020) were retrospectively reviewed. Patients were divided into 2 cohorts: "open" (n = 92) and "endoscopic" (n = 52). Logistic regression was performed to evaluate the impact of procedural type on postoperative outcomes, and resource utilization metrics were compared between cohorts using χ 2 test (for categorical variables) or t test (for continuous variables). Primary postsurgical outcomes included readmissions, reoperations, emergency department visits, and neurosurgery outpatient office visits within 90 days of the index operation. Primary resource utilization outcomes included total direct cost of the procedure and length of stay. Secondary measures included discharge disposition, operative length, and duration of follow-up. RESULTS: No differences were observed in adverse postoperative events. Patients undergoing open FLDH surgery were more likely to attend outpatient visits within 30 days (P = 0.016). Although direct operating room cost was lower (P < 0.001) for open procedures, length of hospital stay was longer (P < 0.001). Patients undergoing open surgery also demonstrated less favorable discharge dispositions, longer operative length, and greater duration of follow-up. CONCLUSIONS: While both procedure types represent viable options for FLDH, endoscopic surgeries appear to achieve comparable clinical outcomes with decreased perioperative resource utilization. CLINICAL RELEVANCE: The present study suggests that endoscopic FLDH repairs do not lead to inferior outcomes but may decrease utilization of perioperative resources.

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.

Percutaneous Endoscopic Discectomy Via a Transforaminal Approach for L5/S1 Far-Lateral Disc Herniation Assisted by Intraoperative Computed Tomography.

OBJECTIVE: To examine the clinical outcomes of a percutaneous lumbar transforaminal endoscopic discectomy (PTED) with intraoperative computed tomography (iCT) navigation for the treatment of L5-S1 far-lateral lumbar disc herniation (LDH). METHODS: A total of 30 patients with L5-S1 far-lateral LDH who underwent PTED with iCT navigation from September 2016 to October 2020 were enrolled in this study. Outcomes were assessed using the visual analog scale pain score, the Oswestry Disability Index, the Japanese Orthopedic Association score, the EQ-5D-5 L and the modified Macnab criteria. Preoperative and postoperative complications were recorded. RESULTS: The mean visual analog scale score for leg pain improved from 8.1 at baseline to 2.3, 0.9, 0.7 and 0.9 at 1 day, 1 week, 6 months, and 12 months postoperatively, respectively (P < 0.01). The mean Oswestry Disability Index improved from 78.1% at baseline to 45.5%, 21.9%, 12.6%, and 11.7% at 1 week, 1 month, 6 months, and 12 months postoperatively, respectively (P < 0.01); and the mean Japanese Orthopedic Association score improved from 8.6 at baseline to 14.2, 20.2, 24.4, and 25.6 at 1 day, 1 week, 6 months, and 12 months postoperatively, respectively (P < 0.01). At 12 months postoperatively, the EQ-5D-5 L value significantly increased, from -0.061 ± 0.138 to 0.903 ± 0.064. The rate of a good or excellent modified Macnab result was 93% (26/28) at 12 months postoperatively. In the present study, combined L5-S1 foraminal stenosis tended to lead poor outcomes, which required more postsurgical treatments. CONCLUSIONS: With iCT navigation, PTED is a feasible and effective minimally invasive surgery for L5-S1 far-lateral LDH.

Clinical experience on intertransverse extraforaminal approach for far lateral disc herniations: 132 cases.

Background: Far lateral disc herniations attract many spine surgeons for their type of onset, degree of pain, risk of neurological deficit, and increasing incidence. Today, a direct approach to the region by miminally invasive techniques is preferred. Aims: We aimed to present the results of the cases that were operated via intertransverse extraforaminal approach through a midline incision. Patients and Methods: One hundred thirty-two patients who were operated for far lateral disc herniation by extraforaminal approach between January 2010 and December 2017 were retrospectively evaluated. The demographical data, level of disc herniations, examination findings, preoperative and postoperative VAS scores, and postoperative long-term MacNab satisfaction rates were recorded. Results: Sixty-nine of the patients were male. The mean age was 58.1 years. Acute onset pain was a dominant complaint in 75% of the cases. The mean preoperative VAS score of 8.24 decreased to 2.08 at one month postoperatively. Based on a mean follow-up of 34.4 months, the long-term satisfaction rates according to Macnab criteria were 74% excellent-good, 20% moderate, and 6% poor. Conclusion: Intertransverse extraforaminal approach is an effective and safe technique for far lateral disc herniations. However, considering the anatomical restrictions and the unfamiliarity of the surgeons with the region, it is important that the surgeons perform the surgery with the technique they know best to increase the success of the surgery.

Outcomes Following Discectomy for Far Lateral Disc Herniation Are Not Predicted by Obstructive Sleep Apnea.

Introduction Previous studies have demonstrated that obstructive sleep apnea (OSA) is associated with adverse postoperative outcomes, but few studies have examined OSA in a purely spine surgery population. This study investigates the association of the STOP-Bang questionnaire, a screening tool for undiagnosed OSA, with adverse events following discectomy for far lateral disc herniation (FLDH). Methods All adult patients (n = 144) who underwent FLDH surgery at a single, multihospital, academic medical center (2013-2020) were retrospectively enrolled. Univariate logistic regression was performed to evaluate the relationship between risk of OSA (low- or high-risk) according to STOP-Bang score and postsurgical outcomes, including unplanned hospital readmissions, ED visits, and reoperations. Results Ninety-two patients underwent open FLDH surgery, while 52 underwent endoscopic procedures. High risk of OSA according to STOP-Bang score did not predict risk of readmission, ED visit, outpatient office visit, or reoperation of any kind within either 30 days or 30-90 days of surgery. High risk of OSA also did not predict risk of reoperation of any kind or repeat neurosurgical intervention within 30 days or 90 days of the index admission (either during the same admission or after discharge). Conclusion The STOP-Bang questionnaire is not a reliable tool for predicting post-operative morbidity and mortality for FLDH patients undergoing discectomy. Additional studies are needed to assess the impact of OSA on morbidity and mortality in other spine surgery populations.

Charlson Comorbidity Index score predicts adverse post-operative outcomes after far lateral lumbar discectomy.

INTRODUCTION: The Charlson Comorbidity Index (CCI) score has been shown to predict 10-year all-cause mortality and post-neurosurgical complications but has never been examined in a far lateral disc herniation (FLDH) population. This study aims to correlate CCI score with adverse outcomes following FLDH repair. PATIENTS AND METHODS: All patients (n = 144) undergoing discectomy for FLDH at a single, multihospital academic medical system (2013-2020) were retrospectively analyzed. CCI scores were determined for all patients. Univariate logistic regression was used to determine the ability of CCI score to predict adverse outcomes. RESULTS: Mean age of the population was 61.72 ± 11.55 years, 69 (47.9%) were female, and 126 (87.5%) were non-Hispanic white. Patients underwent either open (n = 92) or endoscopic (n = 52) FLDH repair. Average CCI score among the patient population was 2.87 ± 2.42. Each additional point in CCI score was significantly associated with higher rates of readmission (p = 0.022, p = 0.014) in the 30-day and 30-90-day post-surgery window, respectively, and emergency department visits (p = 0.011) within 30-days. CCI score also predicted risk of reoperation of any kind (p = 0.013) within 30 days of the index operation. In addition, CCI score was predictive of risk of reoperation of any kind (p = 0.008, p < 0.001; respectively) and repeat neurosurgical intervention (p = 0.027, p = 0.027) within 30-days and 90-days of the index admission (either during the same admission or after discharge). CONCLUSIONS: This study suggests that CCI score is a useful metric to predict of numerous adverse postoperative outcomes following discectomy for FLDH.

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.

Percutaneous Endoscopic Transforaminal Approach for Far Lateral Lumbar Discectomy: 2-Dimensional Operative Video.

The conventional surgical approach to far lateral lumbar disk herniations is a paraspinal Wiltse approach. During the Wiltse approach, it is sometimes necessary to resect some of the facet or pars interarticularis to achieve an adequate exposure. The endoscopic transforaminal route can be of benefit in far lateral disk herniations due to direct access to the epidural space through Kambin's triangle, without the need for any bony removal or nerve retraction. In this video, we describe a percutaneous endoscopic transforaminal approach for far lateral discectomy in a patient presenting with a left L4 radiculopathy due to a far lateral L4-5 disk herniation. We describe Kambin's triangle anatomy and its relevance to the transforaminal route. The steps of the procedure are then described: dissection of soft tissue and removal of free disk fragments on the inferior aspect of the foramen far from the compressed exiting nerve route above to decrease the risk of retraction injury, gentle maneuvering of endoscope superiorly with removal of further compressive disk fragments, exposure of the exiting nerve root superiorly after adequate decompression is achieved and removal of any remaining fragments in close proximity to the nerve, and finally evaluation of traversing nerve root for any compressive lesions. The presentation ends with postoperative imaging confirming decompression of the far lateral disk herniation.

Minimally invasive surgical techniques for the therapy of far lateral disc herniation in middle-aged and elderly patients.

To examine the clinical results of different minimally invasive techniques for the therapy of far lateral disc herniation in middle-aged and elderly patients. An endoscopic approach (percutaneous endoscopic lumbar discectomy; PELD), MIS-TLIF combined with contralateral translaminar screw (MIS-TLIF CTS), and MIS-TLIF combined with bilateral pedicle screws (MIS-TLIF BPS) were evaluated via a retrospective chart review. Data from 74 consecutive middle-aged and elderly patients with far lateral disc herniation were analyzed. All patients underwent surgery; 19 with PELD, 24 with MIS-TLIF CTS, and 31 with MIS-TLIF BPS. Clinical data included the length of the incision, duration of the operation, estimated blood loss, hospitalization time, operation cost, recurrence rate, and fusion rate. Preoperative and postoperative patient outcomes including the VAS, ODI scores and MacNab criteria were assessed and recorded. The mean follow-up time was 26.4 months (range from 14 to 46 months). Compared with the internal fixation groups, the length of the incision, duration of operation, estimated blood loss, and hospitalization time were obviously lower in the PELD group. The difference in operation cost among the three methods was statistically significant. The postoperative VAS scores for LBP and LP decreased significantly as compared with those recorded preoperatively. The postoperative ODI scores were lower than those recorded preoperatively. MacNab criteria rating excellent, good and fair results were in 27, 37 and 10 patients, respectively. Conclusion: PELD, MIS-TLIF CTS, and MIS-TLIF BPS are all effective minimally invasive techniques for the therapy of single segment far lateral lumbar disc herniation in middle-aged and elderly patients. PELD had a shorter operation time and less surgical trauma, being a less invasive and more economical method; however, there was no recurrence of disc herniation after fixation. Compared with MIS-TLIF BPS, MIS-TLIF CTS obtained a similar clinical effect and certain costs were saved.

Extraforaminal approach of biportal endoscopic spinal surgery: a new endoscopic technique for transforaminal decompression and discectomy.

This study was performed to describe the extraforaminal approach of biportal endoscopic spinal surgery (BESS) as a new endoscopic technique for transforaminal decompression and discectomy and to demonstrate the clinical outcomes of this new procedure for the first time. Twenty-one patients (27 segments) who underwent the extraforaminal approach of BESS between March 2015 and April 2016 were enrolled according to the inclusion and exclusion criteria. The operative time (minutes/level) and complications after the procedure were recorded. The visual analog scale (VAS) score was checked to assess the degree of radicular leg pain preoperatively and at the time of the last follow-up. The modified Macnab criteria were used to examine the clinical outcomes at the time of the last follow-up. The mean duration of the follow-up period was 14.8 months (minimum duration 12 months). The mean operative time was 96.7 minutes for one level. The mean VAS score for radicular leg pain dropped from a preoperative score of 7.5 ± 0.9 to a final follow-up score of 2.5 ± 1.2 (p < 0.001). The final outcome according to the modified Macnab criteria was excellent in 5 patients (23.8%), good in 12 (57.2%), fair in 4 (19.0%), and poor in 0. Therefore, excellent or good results (a satisfied outcome) were obtained in 80.9% of the patients. Complications were limited to one dural tear (4.8%). The authors found that the extraforaminal approach of BESS was a feasible and advantageous endoscopic technique for the treatment of foraminal lesions, including stenosis and disc herniation. They suggest that this technique represents a useful, alternative, minimally invasive method that can be used to treat lumbar foraminal stenosis and disc herniation.

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.

Far lateral microdiscectomy: a minimally-invasive surgical technique for the treatment of far lateral lumbar disc herniation.

Lumbar disc herniation arises when the annulus fibrosus of the vertebral disc fails, thus allowing displacement of the nucleus pulposus and other tissue. The term far lateral is used variably in the literature and usually refers to an extraforaminal displacement in the peridiscal zone peripheral to the sagittal plane of the most lateral part of the pedicle at the same level. Non-surgical treatments of far lateral disc herniation include physical therapy, anti-inflammatory medication, and corticosteroid injections. Where these conservative measures fail, surgical intervention may be required. Several surgical techniques for the treatment of far lateral herniations have been investigated, including total or medial facetectomy, laminectomy, hemilaminectomy, approaches through the pars interarticularis, and lateral approaches between the transverse processes via the intertransverse muscle and ligament. We present our far lateral microdiscectomy technique which involves accessing the nerve root lateral to the foramen through a small paramedian incision and use of an operating microscope. Far lateral microdiscectomy offers the prospect of better long-term results than other surgical techniques because of less extensive muscle dissection and preservation of the integrity of the facet joint.

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.

Far caudally migrated extraforaminal lumbosacral disc herniation treated by a microsurgical lateral extraforaminal transmuscular approach: case report.

A 33-year-old man presented with moderate low-back pain and L-5 radiculopathy that progressed to severe paresis of L-5. On initial imaging, a corresponding spinal lesion was overlooked. Further CT and contrast-enhanced MRI demonstrated a presacral mass along the L-5 root far extraforaminally. A herniated disc was suspected, but with standard imaging a schwannoma could not be ruled out. The presacral L-5 root was explored via a microsurgical lateral extraforaminal transmuscular approach. To the best of the authors' knowledge, there have been no reports of sequestered extraforaminal lumbosacral disc herniations that herniated into the presacral region.

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.

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.

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 (p0.05). 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.

New Diagnostic Tool for Far Lateral Lumbar Disc Herniation : The Clinical Usefulness of 3-Tesla Magnetic Resonance Myelography Comparing with the Discography CT.

OBJECTIVE: To prospectively assess the diagnostic and clinical value of a new technique (3-tesla magnetic resonance myelography, 3T MRM) as compared to computed tomographic discography (disco-CT) in patients with far lateral disc herniation. METHODS: We evaluated 3T MRM and disco-CT of 25 patients, whom we suspected of suffering from far lateral disc herniation. Using an assessment scale, 4 observers examined independently both 3T MRM and disco-CT images. We analyzed observer agreement and the accentuation of each image. RESULTS: We found complete matching, and observer agreement, between high resolution images of 3T MRM and disco-CT for diagnosing far lateral disc herniation. CONCLUSION: We think noninvasive 3T MRM is an appropriate diagnostic tool for far lateral disc herniation as compared to disco-CT.