Comparison of the Outcomes of Microendoscopic Discectomy Versus Full-Endoscopic Discectomy for the Treatment of L4/5 Lumbar Disc Herniation

STUDY DESIGN

Retrospective Comparative Study.

OBJECTIVES

To compare the outcomes of microendoscopic discectomy (MED) versus full-endoscopic discectomy (FED) for treating L4/5 lumbar disc herniation (LDH).

METHODS

A retrospective study was performed on patients with L4/5 LDH treated using MED (n = 249) or FED (n = 124). A 16-mm tubular retractor and endoscope was used for MED, while a 4.1-mm working channel endoscope was used for FED. Patient background and operative data were collected. The Oswestry Disability Index (ODI) and European Quality of Life-5 Dimensions (EQ-5D) scores were recorded preoperatively and at 1 and 2 years postsurgery.

RESULTS

The background data of the two groups were similar. The mean operation times for MED and FED were 59.3 and 47.7 min (respectively), and the mean volumes of removed nucleus pulposus were .65 and 1.03 g, respectively. These differences were significant (P < .001). Six dural tears and one postoperative hematoma were observed in the MED group; none were observed in the FED group. During the follow-up period, 16 MED and 7 FED patients required re-operation due to recurrence (P = 1.00). Although the ODI and EQ-5D scores significantly improved at 1 and 2 years postsurgery in both groups, the differences were not statistically significant.

CONCLUSIONS

Operative outcomes were almost identical in both groups. We did not observe any operative or postoperative complications in FED. We, therefore, recommend FED as the first option for the treatment of L4/5 LDH since it has a better safety profile and is minimally invasive.

A new surgical method to treat intracanal lumbar disc herniation using the unilateral biportal endoscopic transforaminal approach: patient series

BACKGROUND

Unilateral biportal endoscopic lumbar discectomy (UBELD) is a new minimally invasive spine surgery. The purpose of this study is to describe a new surgical method to treat intracanal lumbar disc herniation (LDH) using the unilateral biportal endoscopic transforaminal approach (UBE-TFA). The first 15 patients who had undergone UBELD for single-level LDH were included in this study. Operative time, intraoperative blood loss, postoperative stay, and intraoperative complications were recorded. The Oswestry Disability Index (ODI), numeric rating scale (NRS) score for leg pain, and modified MacNab criteria were assessed at 3 months postoperatively.

OBSERVATIONS

The mean operative time was 52.0 ± 13.8 minutes. The mean intraoperative blood loss was 10.5 ± 10.2 mL. The mean postoperative stay was 1.1 ± 0.3 days. There were no complications. The postoperative mean ODI was significantly improved from 44.9 ± 14.4 to 7.7 ± 11.2 at the final follow-up (p < 0.001). There was a significant decrease in the postoperative mean NRS score for leg pain, from 6.1 ± 1.9 to 0.8 ± 1.3 at the final follow-up (p < 0.001). Based on the modified MacNab criteria, good to excellent results were obtained in 86.7% of the patients.

LESSONS

We considered UBELD-TFA as not only one of the promising surgical methods for UBELD, but also a new surgical implementation of the TFA.

Large-Scale Comparative Study Between Microendoscopic Laminectomy and Full-Endoscopic Laminectomy for the Treatment of Single-Level Lumbar Spinal Canal Stenosis

BACKGROUND

We previously compared the operative outcomes of microendoscopic laminectomy (MEL) and full-endoscopic laminectomy (FEL) for single-level lumbar spinal canal stenosis (LSCS). In this initial report, the operative outcomes of FEL were not inferior to those of MEL.

OBJECTIVE

The purpose of this study is to compare the outcomes of MEL and FEL for single-level LSCS on a large scale using widely used multiple evaluation methods.

METHODS

MEL was performed using a 16 mm tubular retractor and an endoscope, while FEL was performed using a 6.4 mm working channel endoscope. A retrospective study was performed on patients with LSCS treated with MEL (n = 355) or FEL (n = 154). Patient background and operative data were also collected. The Oswestry Disability Index (ODI), European Quality of Life-5 Dimensions (EQ-5D), and 36-item Short Form Survey (SF-36) scores were recorded preoperatively and 1-year postoperatively.

RESULTS

Background data of the two groups and the mean operation time (MEL, 72.1 m; FEL, 74.2 m) were not significant (p>0.2). The mean volumes of intraoperative bleeding (MEL, 25.2 ml; FEL, 10.3 ml) were significantly different (p<0.001). The mean postoperative hospital stays (MEL, 3.9 days; FEL, 2.1 days) were significantly different (p<0.001). Fifteen dural tears (MEL, 11; FEL, 4) and 1 surgical site infection (MEL, 1; FEL, 0) were observed but not significant (p>0.5). Reoperation was required for postoperative hematoma in five patients (MEL, 3; FEL, 2). Although the ODI, EQ-5D, and SF-36 scores improved significantly at one year postoperatively in the MEL and FEL groups (p<0.001), there were no significant differences between the two groups (p>0.1).

CONCLUSION

The operative outcomes and minimal invasiveness were no statistical difference between the MEL and FEL groups. Further development of the operative techniques and the instruments of FEL are required to shorten the operation time.

Interstitial-fluid shear stresses induced by vertically oscillating head motion lower blood pressure in hypertensive rats and humans

The mechanisms by which physical exercise benefits brain functions are not fully understood. Here, we show that vertically oscillating head motions mimicking mechanical accelerations experienced during fast walking, light jogging or treadmill running at a moderate velocity reduce the blood pressure of rats and human adults with hypertension. In hypertensive rats, shear stresses of less than 1 Pa resulting from interstitial-fluid flow induced by such passive head motions reduced the expression of the angiotensin II type-1 receptor in astrocytes in the rostral ventrolateral medulla, and the resulting antihypertensive effects were abrogated by hydrogel introduction that inhibited interstitial-fluid movement in the medulla. Our findings suggest that oscillatory mechanical interventions could be used to elicit antihypertensive effects.

Does surgical site infection affect patient-reported outcomes after spinal surgery? A multicenter cohort study

BACKGROUND

Surgical site infections are common in spinal surgeries. It is uncertain whether outcomes in spine surgery patients with vs. without surgical site infection are equivalent. Therefore, we assessed the effects of surgical site infection on postoperative patient-reported outcomes.

METHODS

We enrolled patients who underwent elective spine surgery at 12 hospitals between April 2017 and February 2020. We collected data regarding the patients' backgrounds, operative factors, and incidence of surgical site infection. Data for patient-reported outcomes, namely numerical rating scale, Neck Disability Index/Oswestry Disability Index, EuroQol Five-Dimensional questionnaire, and 12-Item Short-Form Health Survey scores, were obtained preoperatively and 1 year postoperatively. We divided the patients into with and without surgical site infection groups. Multivariate logistic regression analyses were performed to identify the risk factors for surgical site infection. Using propensity score matching, we obtained matched surgical site infection-negative and -positive groups. Student's t-test was used for comparisons of continuous variables, and Pearson's chi-square test was used to compare categorical variables between the two matched groups and two unmatched groups.

RESULTS

We enrolled 8861 patients in this study; 74 (0.8 %) developed surgical site infections. Cervical spine surgery and American Society of Anesthesiologists physical status classification ≥3 were identified as risk factors; microendoscopy was identified as a protective factor. Using propensity score matching, we compared surgical site infection-positive and -negative groups (74 in each group). No significant difference was found in postoperative pain or dysesthesia of the lower back, buttock, leg, and plantar area between the groups. When comparing preoperative with postoperative pain and dysesthesia, statistically significant improvement was observed for both variables in both groups (p < 0.01 for all variables). No significant differences were observed in postoperative outcomes between the matched surgical site infection-positive and -negative groups.

CONCLUSIONS

Patients with surgical site infections had comparable postoperative outcomes to those without surgical site infections.

Comparison of the Outcomes of Microendoscopic Cervical Foraminotomy versus Full-endoscopic Cervical Foraminotomy for the Treatment of Cervical Radiculopathy

This study aimed to compare the outcomes of microendoscopic cervical foraminotomy (MECF) versus full-endoscopic cervical foraminotomy (FECF) for treating cervical radiculopathy (CR).A retrospective study was performed on patients with CR treated using MECF (n = 35) or FECF (n = 89). A 16-mm tubular retractor and endoscope was used for MECF, while a 4.1-mm working channel endoscope was used for FECF. Patient background and operative data were collected. The numerical rating scale (NRS) and the Neck Disability Index scores were recorded preoperatively and at 1 year postoperatively. Postoperative subjective satisfaction was also assessed.Although the NRS, and NDI scores, as well as postoperative satisfaction at 1 year considerably improved in both groups, one of the background data (number of operated vertebral level) was significantly different. Therefore, we separately analyzed single- and two-level CR. In single-level CR, operation time, intraoperative bleeding, postoperative stay, NDI after 1 year, and reoperation rate were statistically superior in FECF group. In two-level CR, the postoperative stay was statistically superior in FECF group. Three postoperative hematomas were observed in the MECF group, while none was observed in the FECF group.Operative outcomes did not significantly differ between groups. We did not observe postoperative hematoma in FECF even without placement of a postoperative drain. Therefore, we recommend FECF as the first option for the treatment of CR as it has a better safety profile and is minimally invasive.

A multilocular discal cyst extending from the spinal canal to the extraforaminal region: A case report

BACKGROUND

Lumbar discal cysts are intraspinal extradural cysts communicating with the intervertebral disc. The usual location and morphology are in the caudal ventrolateral epidural space of the spinal canal, without extension to the neural foramen or crossing the midline and described as a well-defined homogeneous oval or spherical cyst on low and high signal intensities observed in lumbar lesions on T1- and T2-weighted magnetic resonance imaging, respectively. We report an unusual lumbar discal cyst in terms of the lesion location and morphology.

CASE PRESENTATION

A 33-year-old-man presented with lower back and right anterior thigh pain. Magnetic resonance imaging revealed multilocular cystic lesions in the cranial ventrolateral epidural space at L2-L3 with low and high signal intensities on T1- and T2-weighted magnetic resonance imaging, respectively. We performed a full-endoscopic transforaminal cystectomy under general anesthesia.

CONCLUSION

Lumbar discal cysts should be considered a differential diagnosis for multilocular intraspinal cystic lesion.

Comparison of the Interlaminar and Transforaminal Approaches for Full-endoscopic Discectomy for the Treatment of L4/5 Lumbar Disc Herniation

This study aims to compare the outcomes of interlaminar and transforaminal approaches for full-endoscopic discectomy (FED) for treating L4/5 lumbar disc herniation (LDH).A retrospective study of patients with L4/5 LDH treated with interlaminar endoscopic lumbar discectomy (IELD, n = 19) or transforaminal endoscopic lumbar discectomy (TELD, n = 105) was conducted. Patient background, radiological findings, and operative data were collected. Oswestry Disability Index (ODI) and European Quality of Life-5 Dimension (EQ-5D) scores were recorded preoperatively and 1 and 2 years postoperatively.Although ODI and EQ-5D scores 1 and 2 years postoperatively improved statistically in the IELD and TELD groups, there were no statistical differences between the groups. IELD was predominantly performed in patients who were taller and heavier. The mean operative times and the frequency of laminectomy for IELD and TELD were 67.2 and 44.6 min and 63.2 and 17.1%, respectively (P < 0.001). The radiological findings showed that the concave configuration of the L4 lamina, interlaminar space width, and foraminal width were statistically different between the groups. There were no complications in either of the groups. Reoperation was required for recurrence in two and five patients in the IELD and TELD groups (P = 0.29), respectively.Operative outcomes were identical between the two groups. Although the operative time was longer in the IELD group, both approaches were safely and effectively performed. Depending on the patient's physique and preoperative radiological findings, the more suitable approach for L4/5 LDH should be chosen.

A Propensity Score-matched Analysis of Clinical Outcomes Between Single-level and Multilevel Intervertebral Decompression for Cervical Radiculopathy

STUDY DESIGN

Retrospective multicenter study with propensity score matching.

OBJECTIVE

To compare the clinical outcomes of single-level and multilevel intervertebral decompression for cervical degenerative radiculopathy.

SUMMARY OF BACKGROUND DATA

In patients with cervical radiculopathy, physical examination findings are sometimes inconsistent with imaging data. Multilevel decompression may be necessary for multiple foraminal stenosis. Additional decompression is more invasive yet expected to comprehensively decompress all suspected nerve root compression areas. However, the surgical outcomes of this approach compared with that of single-level decompression remain unknown.

MATERIALS AND METHODS

The data of patients with spinal surgery for pure cervical radiculopathy were collected. Patients were categorized into the single-level (SLDG) or multilevel (MLDG) intervertebral decompression group at C3/C4/C5/C6/C7/T1. Demographic data and patient-reported outcome scores, including the Neck Disability Index (NDI) and Numerical Rating Scale (NRS) scores for pain and numbness in the neck, upper back, and arms, were collected. The NDI improvement rates and changes in NRS scores were analyzed one year postoperatively at patient-reported outcome evaluation. Propensity score matching was performed to compare both groups after adjusting for baseline characteristics, including the preoperative NDI and NRS scores.

RESULTS

Among the 357 patients in this study, SLDG and MLDG comprised 231 and 126 patients, respectively. Two groups (n=112, each) were created by propensity score matching. Compared with the MLDG, the SLDG had a higher postoperative NDI improvement rate ( P =0.029) and lower postoperative arm numbness NRS score ( P =0.037). Other outcomes tended to be more favorable in the SLDG than in the MLDG, yet no statistical significance was detected.

CONCLUSIONS

In patients with cervical radiculopathy, the surgical outcomes of the SLDG showed better improvement in clinical outcomes than those of the MLDG. Numbness remained on the distal (arms) rather than the central (neck and upper back) areas in patients receiving multilevel decompression.

Limitations of minimally invasive posterior cervical foraminotomy-a decompression method of posteriorly shifting the nerve root-in cases of large anterior osteophytes in cervical radiculopathy: A retrospective multicenter cohort study

BACKGROUND

Posterior cervical foraminotomy against anterior osteophyte is an indirect decompression procedure but less invasive compared to anterior cervical discectomy and fusion. Residual compression to the nerve root may lead to poor surgical outcomes. Although clinical results of posterior cervical foraminotomy for osteophytes are not considered better than those of disk herniation, osteophyte size and the association of the decompression area with poor surgical outcomes remain unclear. This study aimed to identify the limitations of minimally invasive posterior cervical foraminotomy for cervical radiculopathy and discuss the methods to improve surgical outcomes.

METHODS

We analyzed 55 consecutive patients with degenerative cervical radiculopathy who underwent minimally invasive posterior cervical foraminotomy. Minimum postoperative follow-up duration was 1 year. We divided the patients into nonimproved and improved groups. The cutoff value between preoperative and postoperative Neck Disability Index scores was 30% improvement. Preoperative imaging data comprised disk height, local kyphosis, spinal cord compression, anterior osteophytes in the foramen, and anterior osteophytes of >50% of the intervertebral foramen diameter. Postoperative imaging data comprised craniocaudal length and lateral width of decompressed lamina, preserved superior facet width, and area of decompressed lamina.

RESULTS

Fifty-five patients were divided into two groups: nonimproved (n = 19) and improved (n = 36). The presence of osteophytes itself was not significant; however, the presence of osteophytes of >50% of the foramen diameter increased in the nonimproved group (P = 0.004). Mean lateral width and mean area of decompressed lamina after surgery significantly increased in the improved group (P = 0.001, P = 0.03).

CONCLUSION

The presence of anterior osteophytes >50% of the diameter of the foramen led to poor improvement of clinical outcomes in minimally invasive posterior cervical foraminotomy. However, the larger the lateral width and area of the decompressed lamina, the better the surgical outcome.

Comparison of Outcomes of Lumbar Interbody Fusion and Full-endoscopic Laminectomy for L5 Radiculopathy Caused by Lumbar Foraminal Stenosis

This study compared the outcomes of microendoscopy-assisted lumbar interbody fusion (ME-LIF) and uniportal full-endoscopic laminectomy (FEL) for L5 radiculopathy caused by lumbar foraminal stenosis (LFS). ME-LIF was performed using an 18- to 20-mm tubular retractor and endoscope, and FEL via the translaminar approach (TLA) was performed at the dorsal part of the foramen using a 4.1-mm working channel endoscope. Patients with LFS treated using ME-LIF (n = 39) or FEL-TLA (n = 30) were retrospectively evaluated. Patients' background and operative data were collected. The 36-item Short Form Survey (SF-36), Oswestry Disability Index (ODI), and European Quality of Life-5 Dimension (EQ-5D) scores were recorded preoperatively and 2 years postoperatively. The background data of the two groups (ME-LIF and FEL-TLA) were similar. The mean operation times for ME-LIF and FEL-TLA were 110.7 and 65.2 min, respectively, and the mean length of hospital stay were 10.3 and 1.5 days, respectively. Reoperation was required for surgical site infection, and percutaneous pedicle screw malposition in three patients was treated using ME-LIF. During follow-up, second FEL-TLA and LIF were performed for recurrent L5 radiculopathy in one and three patients in the FEL-TLA group, respectively. Although the SF-36, ODI, and EQ-5D scores 2 years postoperatively improved in both groups, improvement in ODI scores was lower following FEL-TLA than following ME-LIF. FEL-TLA can be performed to treat patients with L5 radiculopathy caused by LFS. Although the ODI score improvement following FEL-TLA was unremarkable, FEL-TLA might be considered because of its better safety profile and minimal invasiveness than ME-LIF.

Comparison between microendoscopic laminectomy and open posterior decompression surgery for single-level lumbar spinal stenosis: a multicenter retrospective cohort study

Background

Microendoscopic laminectomy (MEL), in which a 16-mm tubular retractor with an internal scope is used, has shown excellent surgical results for patients with lumbar spinal canal stenosis. However, no reports have directly compared MEL with open laminectomy. This study aimed to elucidate patient-reported outcomes (PROs) and perioperative complications in patients undergoing MEL versus open laminectomy.

Methods

This is a multicenter retrospective cohort study of prospectively registered patients who underwent lumbar spinal surgery at one of the six high-volume spine centers between April 2017 and September 2018. A total of 258 patients who underwent single posterior lumbar decompression at L4/L5 were enrolled in the study. With regard to demographic data, we prospectively used chart sheets to evaluate the diagnosis, operative procedure, operation time, estimated blood loss, and complications. The follow-up period was 1-year. PROs included a numerical rating scale (NRS) for lower back pain and leg pain, the Oswestry Disability Index (ODI), EuroQol 5 Dimension (EQ-5D), and patient satisfaction with the treatment.

Results

Of the 258 patients enrolled, 252 (97%) completed the 1-year follow-up. Of the 252, 130 underwent MEL (MEL group) and 122 underwent open decompression (open group). The MEL group required a significantly shorter operating time and sustained lesser intraoperative blood loss compared with the open group. The MEL group showed shorter length of postoperative hospitalization than the open group. The overall complication rate was similar (8.2% in the MEL group versus 7.7% in the open group), and the revision rate did not significantly differ. As for PROs, both preoperative and postoperative values did not significantly differ between the two groups. However, the satisfaction rate was higher in the MEL group (74%) than in the open group (53%) (p = 0.02).

Conclusions

MEL required a significantly shorter operating time and resulted in lesser intraoperative blood loss compared with laminectomy. Postoperative PROs and complication rates were not significantly different between the procedures, although MEL demonstrated a better satisfaction rate.

Influence of Perioperative Antithrombic Agent Discontinuation in Elective Posterior Spinal Surgery: A Propensity-Score-Matched Analysis

OBJECTIVE

To investigate the influence of perioperative antithrombotic agent (antiplatelet agents and anticoagulants) discontinuation in elective posterior spinal surgery in terms of bleeding complications, such as epidural hematoma and postoperative thromboembolism.

METHODS

We enrolled patients undergoing elective posterior spinal surgery at 9 hospitals between April 2017 and August 2020. We collected data regarding patient baseline characteristics, surgical details, intraoperative estimated blood loss, and postoperative complication rates, including epidural hematoma and thromboembolism. We divided the patients into a discontinuation group, in which antithrombic agents were discontinued perioperatively, and a control group without antithrombic agents. Propensity scores for taking any antithrombic agents were calculated, with 1-to-1 matching based on the estimated propensity scores to adjust for patient baseline characteristics and surgical details. Intraoperative estimated blood loss and 30-day postoperative complication rates were compared between the groups.

RESULTS

We enrolled 9853 patients, including 1123 patients (11.4%) who discontinued antithrombic agents perioperatively. One-to-one propensity score matching yielded 1111 pairs with and without antithrombic agents. Intraoperative estimated blood loss per 10 minutes (8.2 mL vs. 8.9 mL) and the incidence of epidural hematoma requiring revision (0.97% vs. 0.72%) were similar between the groups. Although postoperative cardiac events and stroke were observed only in the discontinuation group (0.27% and 0.09%, respectively), these incidences were not significantly different between the groups.

CONCLUSIONS

Perioperative antithrombic agent discontinuation in elective posterior spinal surgery normalized the intraoperative bleeding tendency and the incidence of postoperative epidural hematoma and did not influence in a significative way the incidence of postoperative thromboembolism.

One-year clinical outcome after full-endoscopic interlaminar lumbar discectomy for isthmic lumbar spondylolisthesis: Two case reports

RATIONALE

For isthmic lumbar spondylolisthesis (ILS) associated with the removal of herniation, it remains challenging to perform less invasive and minimally disruptive procedures. Good results could potentially be obtained by further preserving the posterior elements in full-endoscopic lumbar discectomy (FESS), which is less invasive than microenscopic surgery (MES).

PATIENT CONCERNS

One patient complained of left leg pain, and another patient complained of right leg pain and low back pain.

DIAGNOSES

Two patients with ILS and Meyerding Grade 1 lumbar spondylolisthesis.

INTERVENTIONS

We performed a full-endoscopic lumbar discectomy via the interlaminar space (FESS-IL) for L5/S1 lumbar disc herniation (LDH) accompanied by isthmic lumbar spondylolisthesis. FESS-IL was performed in 2 patients with radiculopathy caused by different types of LDH using a full endoscopic system with a 4.1 mm working channel and 6.9 mm outer diameter. A 3.5-mm diameter high-speed drill was used in one patient for an upward-migrated LDH in the inner-rim of the infravertebral border. The other patient underwent minimal resection without bone resection.

OUTCOMES

The one-year clinical outcome included confirmation of pain relief and evacuation of migrated LDH on magnetic resonance imaging in all patients. There was no progression of slippage on radiography. The mean operative time was 82 min, and no complication was observed. The one-year clinical outcome demonstrated sufficient pain relief.

LESSONS THE Y

ear postoperative outcome showed improvement. We believe that FESS-IL is a viable alternative operative approach for LDH for ILS.

The Diagnostic Value of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for the Detection of Surgical Site Infection after Spine Surgery

STUDY DESIGN

Retrospective case series.

OBJECTIVE

The purpose of this study was to assess the diagnostic yield of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) for surgical site infection (SSI) after spine surgery.

SUMMARY OF BACKGROUND DATA

Diagnosis of SSI in the spine based on F-18 FDG PET/CT requires experienced nuclear medical physicians for a detailed analysis of F-18 FDG distribution pattern. It has also been reported that increases in the maximal standardized uptake values of F-18 FDG (SUVmax) closely correlated with SSI, suggesting potential of more objective and quantitative diagnosis.

METHODS

We assessed the diagnostic yield of F-18 FDG PET/CT (pattern-based diagnosis by nuclear medical physicians and SUVmax-based diagnosis) for SSI in 52 subjects who underwent spine surgery. The 52 subjects included 11 nonimplant and 41 implant cases. F-18 FDG PET/CT was performed in 33 and 19 cases in early (≤12 weeks after the surgery) and late (>12 weeks) phases, respectively. The final diagnosis of SSI was based on the results of pathogen identification, plain radiography, and CT and/or magnetic resonance imaging or response to antibiotics and/or reoperation.

RESULTS

SUVmax-based diagnosis was performed with a cut off value of 5.0 as determined by receiver operating characteristic analysis. Both pattern-based and SUVmax-based diagnoses demonstrated excellent diagnostic yields with high sensitivity (97% and 90%), specificity (100% and 100%), and accuracy (98% and 94%). High diagnostic yields (accuracy of ≥90%) were consistently observed irrespective of presence or absence of implantation or interval between surgery and F-18 FDG PET/CT.

CONCLUSION

F-18 FDG PET/CT can be the procedure of choice for investigation of SSI in the spine when other imaging fails to provide a definitive diagnosis.Level of Evidence: 4.

Risk factors for deep surgical site infection after posterior cervical spine surgery in adults: a multicentre observational cohort study

Surgical site infection (SSI) is a serious complication following spine surgery and is correlated with significant morbidities, poor clinical outcomes, and increased healthcare costs. Accurately identifying risk factors can help develop strategies to reduce this devastating consequence; however, few multicentre studies have investigated risk factors for SSI following posterior cervical spine surgeries. Between July 2010 and June 2015, we performed an observational cohort study on deep SSI in adult patients who underwent posterior cervical spine surgery at 10 research hospitals. Detailed patient- and procedure-specific potential risk variables were prospectively recorded using a standardised data collection chart and were reviewed retrospectively. Among the 2184 consecutive adult patients enrolled, 28 (1.3%) developed postoperative deep SSI. Multivariable regression analysis revealed 2 statistically significant independent risk factors: occipitocervical surgery (P < 0.001) and male sex (P = 0.024). Subgroup analysis demonstrated that occipitocervical surgery (P = 0.001) was the sole independent risk factor for deep SSI in patients with instrumented fusion. Occipitocervical surgery is a relatively rare procedure; therefore, our findings were based on a large cohort acquired using a multicentre study. To the best of our knowledge, this is the first study to identify occipitocervical procedure as an independent risk variable for deep SSI after spinal surgery.

Clinical Evaluation of Microendoscopy-Assisted Oblique Lateral Interbody Fusion

Background and objectives: Oblique Lateral Interbody Fusion (OLIF) is a widely performed, minimally invasive technique to achieve lumbar lateral interbody fusion. However, some complications can arise due to constraints posed by the limited surgical space and visual field. The purpose of this study was to assess the short-term postoperative clinical outcomes of microendoscopy-assisted OLIF (ME-OLIF) compared to conventional OLIF. Materials and Methods: We retrospectively investigated 75 consecutive patients who underwent OLIF or ME-OLIF. The age, sex, diagnosis, and number of fused levels were obtained from medical records. Operation time, estimated blood loss (EBL), and intraoperative complications were also collected. Operation time and EBL were only measured per level required for the lateral procedure, excluding the posterior fixation surgery. The primary outcome measure was assessed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The secondary outcome measure was assessed using the Oswestry Disability Index (ODI) and the European Quality of Life–5 Dimensions (EQ-5D), measured preoperatively and 1-year postoperatively. Results: This case series consisted of 14 patients in the OLIF group and 61 patients in the ME-OLIF group. There was no significant difference between the two groups in terms of the mean operative time and EBL (p = 0.90 and p = 0.50, respectively). The perioperative complication rate was 21.4% in the OLIF group and 21.3% in the ME-OLIF group (p = 0.99). In both groups, the postoperative JOABPEQ, EQ-5D, and ODI scores improved significantly (p < 0.001). Conclusions: Although there was no significant difference in clinical results between the two surgical methods, the results suggest that both are safe surgical methods and that microendoscopy-assisted OLIF could serve as a potential alternative to the conventional OLIF procedure.

Risk factors for deep surgical site infection following posterior instrumented fusion for degenerative diseases in the thoracic and/or lumbar spine: a multicenter, observational cohort study of 2913 consecutive cases

PURPOSE

Surgical site infection (SSI) is one of the most devastating complications following spinal instrumented fusion surgeries because it may lead to a significant increase in morbidity, mortality, and poor clinical outcomes. Identifying the risk factors for SSI can help in developing strategies to reduce its occurrence. However, data on the risk factors for SSI in degenerative diseases are limited. This study aimed to identify risk factors for deep SSI following posterior instrumented fusion for degenerative diseases in the thoracic and/or lumbar spine in adult patients.

METHODS

This was a multicenter, observational cohort study conducted at 10 study hospitals between July 2010 and June 2015. The subjects were consecutive adult patients who underwent posterior instrumented fusion surgery for degenerative diseases in the thoracic and/or lumbar spine and developed SSI. Detailed patient-specific and procedure-specific potential risk variables were prospectively recorded using a standardized data collection chart and retrospectively reviewed.

RESULTS

Of the 2913 enrolled patients, 35 developed postoperative deep SSI (1.2%). Multivariable regression analysis identified three independent risk factors: male sex (P = 0.002) and American Society of Anesthesiologists (ASA) score of ≥ 3 (P = 0.003) as patient-specific risk factors, and operation including the thoracic spine (P = 0.018) as a procedure-specific risk factor.

CONCLUSION

Thoracic spinal surgery, an ASA score of ≥ 3, and male sex were risk factors for deep SSI after routine thoracolumbar instrumented fusion surgeries for degenerative diseases. Awareness of these risk factors can enable surgeons to develop a more appropriate management plan and provide better patient counseling.

Anatomical study of cervical intervertebral foramen in patients with cervical spondylotic radiculopathy

PURPOSE

To determine the underlying anatomical characteristics in patients with cervical spondylotic radiculopathy (CSR) by comparing those of surgically treated CSR patients with those of healthy subjects.

METHODS

Computed tomography (CT) scans of the cervical spine in 42 patients who underwent decompression surgery for CSR were investigated. As a control group, 42 age- and sex-matched healthy subjects were randomly selected from the 1272 subjects who underwent CT examinations of the entire spine as their routine medical check-up. Image measurements included C2-7 sagittal Cobb angle, spinal canal diameters, and angles of the nerve root groove at each level from C3 to C7, and the size of the intervertebral foramen and the size of osteophytes at each level from C3/4 to C7/T1. As for the frequency of osteophytes at the surgical level, we compared the operated and nonoperated intervertebral foramina among the CSR patients, and all other parameters were compared with the corresponding segments in the control group.

RESULTS

Forty-eight intervertebral segments were surgically treated in the CSR group. There was a higher incidence of osteophytes in the operated foramen (70.8%) than in the nonoperated foramen (28.2%, p < 0.01) in the patients with CSR. The anteroposterior diameter (width) of the foramen was significantly smaller at all levels in the CSR patients, whereas the height of the foramen did not significantly differ between the two groups.

CONCLUSION

It can be speculated that the width of the intervertebral foramen (developmental factor) and the formation of osteophytes (spondylotic factor) were related to the onset of the CSR.

Microendoscopic Posterior Decompression for Treating Thoracic Myelopathy Caused by Ossification of the Ligamentum Flavum: Case Series

Background and Objectives: Ossification of the ligamentum flavum (OLF) is a relatively common cause of thoracic myelopathy. Surgical treatment is recommended for patients with myelopathy. Generally, open posterior decompression, with or without fusion, is selected to treat OLF. We performed minimally invasive posterior decompression using a microendoscope and investigated the efficacy of this approach in treating limited type of thoracic OLF. Materials and Methods: Microendoscopic posterior decompression was performed for 19 patients (15 men and four women) with thoracic OLF with myelopathy aged between 35 to 81 years (mean age, 61.9 years). Neurological examination and preoperative magnetic resonance imaging (MRI) and computed tomography (CT) were used to identify the location and morphology of OLF. The surgery was performed using a midline approach or a unilateral paramedian approach depending on whether the surgeon used a combination of a tubular retractor and endoscope. The numerical rating scale (NRS) and modified Japanese Orthopedic Association (mJOA) scores were compared pre- and postoperatively. Perioperative complications and the presence of other spine surgeries before and after thoracic OLF surgery were also investigated. Results: Four midline and 15 unilateral paramedian approaches were performed. The average operative time per level was 99 min, with minor blood loss. Nine patients had a history of cervical or lumbar spine surgery before or after thoracic spine surgery. The mean pre- and postoperative NRS scores were 6.6 and 5.3, respectively. The mean recovery rate as per the mJOA score was 33.1% (mean follow-up period, 17.8 months), the recovery rates were significantly different between patients who underwent thoracic spine surgery alone (50.5%) and patients who underwent additional spine surgeries (13.7%). Regarding adverse events, one patient experienced dural tear, another experienced postoperative hematoma, and one other underwent reoperation for adjacent thoracic stenosis. Conclusion: Microendoscopic posterior decompression was applicable in limited type of thoracic OLF surgery including beak-shaped type and multi vertebral levels. However, whole spine evaluation is important to avoid missing other combined stenoses that may affect outcomes.

Is Microendoscopic Discectomy Effective for Patients With Concomitant Lumbar Disc Herniation and Spondylolysis?

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

Although it is controversial whether to choose only discectomy or fusion surgery in patients with disc herniation and spondylolysis, we expected that aggravation of the spondylolysis may be prevented if posterior supporting muscles can be well-preserved without extensive exploration. The purpose of this study was to investigate the influence of L5 spondylolysis on surgical outcomes following microendoscopic discectomy (MED) in patients with concomitant lumbar disc herniation and spondylolysis.

METHODS

We reviewed 811 patients who underwent MED for L4/5 or L5/S1 disc herniation. Patients with spondylolisthesis were excluded. We compared surgical outcomes of patients with and without L5 spondylolysis, whose age, sex, and surgical level were matched.

RESULTS

A total of 655 patients (80.7%) with complete data were considered eligible for the study. MED was performed at L4/5 and L5/S1 in 338 and 317 patients, respectively. A total of 20 patients (3.1%) had concomitant L5 spondylolysis and disc herniation at L4/5 (9 patients) or L5S1 (11 patients). As we compared each outcome of the 20 patients having L5 spondylolysis with 40 matched patients without L5 spondylosis, there were no significant differences in preoperative or postoperative outcomes between the 2 groups, and no patient with spondylolysis had undergone additional surgery during the mean follow-up period of 24 months.

CONCLUSIONS

MED demonstrated good surgical results regardless of the presence or absence of spondylolysis. In patients with sciatica with concomitant disc herniation and spondylolysis, but without spondylolisthesis, fusion surgery may not be always necessary.

A less invasive treatment by a full-endoscopic spine surgery for adjacent segment disease after lumbar interbody fusion

Background

Full-endoscopic spine surgery (FESS) is a suitable treatment for lumbar disc herniation (LDH) and foraminal stenosis. This study investigated the usefulness of FESS in treating adjacent segment disease (ASD) after lumbar interbody fusion (LIF).

Methods

Between September 2015 and March 2019, a total of 13 patients with symptomatic ASD after LIF underwent FESS. Discectomy and foraminoplasty using a 3.5-mm diameter high-speed drill were performed for treating LDH and foraminal stenosis. Preoperative and postoperative statuses were evaluated using Numerical Rating Scale (NRS) and the modified Japanese Orthopedic Association (mJOA) scores.

Results

The patients' mean age was 64.8 years; there were 10 male and 3 female patients. The mean operative time was 52.7 min. The mean pre- and postoperative NRS scores were 7.6 and 3.1, respectively. The mean pre- and postoperative mJOA scores were 10.5 and 16.1, respectively, and the mean recovery rate was 32.8%. Subsequent operative treatments were required in 3 patients for postoperative complication, insufficient decompression, and recurrence LDH.

Conclusions

FESS is a safe and effective minimally invasive treatment for ASD after LIF and a potential alternative to extend the LIF to the adjacent vertebra or sacrum.

Full-endoscopic spine surgery for radiculopathy after osteoporotic vertebral compression fractures: a case report

Full-endoscopic spine surgery (FESS) is a suitable treatment for lumbar disc herniation (LDH) and foraminal stenosis. Here, we describe the usefulness of FESS for treating radiculopathy after osteoporotic vertebral compression fractures (OVCFs). Between October 2018 and April 2019, three female patients (mean age, 81.7 years) with radiculopathy after OVCFs underwent FESS. Decompression of the corresponding nerve root was achieved using several FESS techniques, including foraminoplasty, discectomy, and removal of osteophyte or cement leakage. The mean operative time was 60.7 min. Preoperative and postoperative statuses were evaluated using numerical rating scale (NRS) scores. The mean pre- and postoperative NRS scores were 9 and 2.3, respectively. We observed no postoperative complications. Our results demonstrate that FESS is a safe and effective minimally invasive treatment for radiculopathy after OVCFs, with the potential to be an alternative to vertebroplasty, balloon kyphoplasty (BKP), or lumbar interbody fusion.

Full-Endoscopic Spine Surgery for the Treatment of Lumbar Ossification of the Ligamentum Flavum: Technical Report

BACKGROUND

Ossification of the ligamentum flavum (OLF) is a relatively common disease in East Asia. Although surgical decompression using a posterior approach is commonly used to treat OLF, there are several different treatment strategies. The purpose of this study is to clarify the technically important points for the treatment of OLF using full-endoscopic spine surgery (FESS).

METHODS

FESS was performed on 7 patients with lumbar OLF. Patients had a mean age of 62.3 years and single-level involvement. Computed tomography and magnetic resonance imaging were used to classify the OLF. Two different types of spinal endoscope were used for posterior decompression. Interlaminal and translaminal approaches were performed in 6 and 1 patient, respectively. Preoperative and postoperative pain was evaluated using the numeric rating scale score.

RESULTS

The mean operation time was 84.1 minutes. Unilateral round-type OLF was treated using a 4.1-mm working channel endoscope. The bilateral type was treated using a 6.4-mm working channel endoscope. A dural tear occurred in 1 patient with beak-type OLF, but no symptoms resulting from the tear were observed. The mean preoperative and postoperative numeric rating scale scores were 7.7 and 1.6, respectively.

CONCLUSIONS

Posterior decompression using FESS can be used to treat patients with lumbar OLF. Unilateral round-type OLF with ipsilateral radiculopathy can be treated using a 4.1-mm working channel endoscope. Bilateral-type OLF with cauda equina symptoms should be treated using a 6.4-mm working channel endoscope.

Degree of satisfaction following full-endoscopic cervical foraminotomy

Background

Foraminotomy has been reported to be effective for the treatment of cervical radiculopathy (CR). Foraminotomy has been performed by an open approach or minimally invasive approach using a microscope or endoscope. A review of the literature has revealed that both the open and minimally invasive approach provide good clinical results. Since the introduction of full-endoscopic cervical foraminotomy (FECF) followed by microendoscopic cervical foraminotomy, we adopted FECF in 2016. The purpose of this study was to evaluate the degree of satisfaction following FECF for CR.

Methods

A total of 109 consecutive patients underwent FECF for CR. All operations were performed at Iwai Orthopaedic Medical Hospital. Patient background information and operative data were collected. The numerical rating scale (NRS) score for the arm was assessed preoperatively and postoperatively at the time of discharge from the hospital. The satisfaction score was also recorded at discharge and the 3 months after the operation.

Results

In total 109 patients, the mean age was 51.3 years; 22.9% were female and 77.1% were male. The cervical level most frequently operated on was C6/7, followed by C5/6. The mean hospital stay was 4.7 days. The mean operation time was 61.7 minutes. The estimated blood loss was 0 to 10 mg in all cases. One patient exhibited temporary postoperative muscle weakness, although he recovered within 1 year. There was one case of dural tear, and no cases of nerve root injury or surgical site infection. There was one case of reoperation by microendoscopic surgery in 3 months due to insufficient improvement. Preoperative NRS scores for the arm was 4.6 and it improved significantly postoperatively to 2.1 for the entire study group. The mean satisfaction score at discharge was 7.5. The mean score at 3 months after the operations was 7.4.

Conclusions

Degree of satisfaction following FECF for CR was high 3 months after the operation.

Comparative study between full-endoscopic laminectomy and microendoscopic laminectomy for the treatment of lumbar spinal canal stenosis

Background

Lumbar spinal canal stenosis (LSCS) is a common disease in the elderly. Although surgical decompression using a posterior approach is commonly used to treat LSCS, there are several different strategies. We compared the outcomes of uniportal full-endoscopic laminectomy (FEL) and microendoscopic laminectomy (MEL) for treating LSCS.

Methods

FEL was performed using a 6.4-mm working channel endoscope and MEL was performed using a 16-mm diameter tubular retractor and endoscope. Patients with LSCS treated with FEL (n=60) and MEL (n=54) in our hospital during the same period were retrospectively reviewed. Patient background information and operative data were collected. The satisfaction score was also recorded at discharge and 3 months postoperatively.

Results

The mean operation time for FEL and MEL was 77.8 min and 54.6 min, respectively. The mean hospital stay after FEL and MEL surgery was 2.1 days and 4.7 days, respectively. These outcomes were significantly different between the two approaches. The satisfaction scores at both stages were not significantly different between the two groups. A dural tear occurred in one patient who underwent FEL and three patients who underwent MEL, but no symptoms resulted from the tear. Although postoperative hematoma occurred in seven who underwent FEL and two who underwent MEL, only one patient who underwent FEL required operative evacuation of the hematoma.

Conclusions

FEL using a 6.4-mm working channel endoscope can be used to treat patients with LSCS. Shortening of the operation time and prevention of postoperative hematoma are essential for this approach to be completely superior to MEL.

Incidence, prognosis, and risk factors for bladder and bowel dysfunction due to incidental dural tears in lumbar microendoscopic surgery

BACKGROUND CONTEXT

Despite the common occurrence of incidental dural tears, the incidence and prognosis of bladder and bowel dysfunction (BBD) due to incidental dural tears in lumbar spinal surgery are not well known because of the lack of reported cases.

PURPOSE

To analyze the incidence, prognosis, and risk factors for BBD after lumbar microendoscopic surgery with or without incidental dural tears.

STUDY DESIGN/SETTING

A retrospective cohort study.

PATIENT SAMPLE

We analyzed 2,421 patients who underwent lumbar microendoscopic surgery and investigated patients with BBD after an incidental durotomy during surgery.

OUTCOME MEASURES

Patients were divided into three groups on the basis of dysuria and defecation disorders: severe BBD, mild BBD, and no BBD. The post void residual volumes before and after surgery were compared using an ultrasound bladder scanner or bladder catheterization after confirmation of urination. Bowel dysfunction was evaluated by subjective symptomatic deterioration and the increase in the frequency and duration of postoperative medical care.

METHODS

Risk factors for BBD were analyzed using surgical video documentation to determine the dural tear site and cauda equina exposure from the dural sac. Patients with BBD were prospectively followed up for prognosis determination. The chi-square test was used to compare the incidence of BBD between patients with dural tears and those without. Propensity score-adjusted logistic regression analysis was performed to evaluate the effects of various factors on the incidence of postoperative BBD.

RESULTS

The incidence of dural tears was 6.9% (168/2,421). The overall incidence of BBD was 3.0% (73/2,421), while the incidences of BBD (mild+severe BBD) and severe BBD due to incidental dural tears were 1.2% (30/2,421) and 0.8% (20/2,421), respectively. The incidence of BBD in patients with dural tears and those without tears was 17.9% [30/168] and 1.9% [43/2,253; p<.001]), respectively. BBD rates at 1 week, 1 month, 3 months, 6 months, and 1 year after surgery were 64.0%, 44.0%, 40.0%, 28.0%, and 13.6%, respectively. Logistic regression analysis revealed that the male sex (odds ratio [OR], 4.20), dural tears in the central area (OR, 10.15), and exposure of the cauda equina (OR, 51.04) were significant risk factors.

CONCLUSIONS

The incidence of dural tears in lumbar microendoscopic surgeries are associated with an increased incidence of BBD. The recovery rate for BBD due to incidental dural tears is generally good; however, some patients experience long-term symptoms. Clinicians should be aware that incidental dural tears with cauda equina exposure can increase the risk of BBD.

Clinical and radiographic analysis of unilateral versus bilateral instrumented one-level lateral lumbar interbody fusion

Lateral lumbar interbody fusion (LLIF) is a widely applied and useful procedure for spinal surgeries. However, posterior fixation has not yet been decided. We compared the radiographic and clinical outcomes of unilateral versus bilateral instrumented one-level LLIF for degenerative lumbar disease. We conducted a prospective cohort study of 100 patients, who underwent unilateral (group U) or bilateral (group B) instrumented one-level LLIF for degenerative lumbar disease. Forty-one patients in group U were undergoing unilateral pedicle screw instrumentation, and 59 patients in group B were undergoing bilateral pedicle screw instrumentation. Clinical characteristic and demographic data before surgery were compared. The intraoperative data, including operative time with changes in positions, intraoperative blood loss, and X-ray exposure time, as well as the perioperative data, including postoperative hospital stay and clinical and radiographic data were compared. As a result, Group U required a significantly shorter operating time than group B. The subsidence grade and fusion rates exhibited no significant differences in the postoperative radiographic evaluation. Group U had better results in clinical assessments than group B. However, group U required more additional surgeries owing to complications.

C5 palsy after C5/6/7 posterior foraminal decompression: A case report

RATIONALE

Although C5 palsy is a common complication of cervical spine surgery, its cause has not been confirmed. There are various hypotheses for its mechanism, including spinal cord impairment and nerve involvement. Therefore, prophylactic foraminotomy is one of the methods recommended for preventing C5 palsy. However, we describe a patient who experienced C5 palsy after microendoscopic foraminotomy between the left C5/6 and C6/7 levels.

PATIENT CONCERNS

A 43-year-old man presented with a 14-month history of progressive numbness in the left upper limb. We performed microendoscopic left foraminal decompressions at the C5/6/7 levels to treat the left C6 and C7 radiculopathy. On the postoperative day 1, we observed weak motor strength of the left deltoid, left biceps, and left forearm pronator, while the motor strength of the other muscles was normal.

DIAGNOSES

C5 palsy following C5/6/7 left foraminotomy.

INTERVENTION

Follow-up rehabilitation with muscle strength training and range of motion training.

OUTCOME

The patient recovered his motor strength completely within 3 months postoperatively.

LESSONS

In this case, the C5 palsy could not be adequately explained by the theory of nerve root impingement or disruption in blood circulation following spinal cord decompression. We hypothesized that the patient had drill heat-induced C5 palsy. Regarding the C5 palsy without C5 nerve root decompression, we hypothesize that the C5 palsy in C5/6/7 foraminotomy could be related to variations in the formation of the brachial plexus. Prophylactic foraminotomy for cervical posterior surgery should be performed with care, limiting its use in patients who are at a risk of developing C5 palsy because the prophylactic procedure can cause C5 palsy. We must also consider that even without decompression at the C4/5 level, there is a possibility of C5 palsy occurring.

A protective method to reduce radiation exposure to the surgeon during endoscopic lumbar spine surgery

BACKGROUND

Endoscopic lumbar spine surgery is a minimally invasive technique that requires intraoperative fluoroscopic imaging. Fluoroscopy is a source of ionizing radiation, and exposure of the surgeon to this radiation has a risk for radiation-induced morbidities. To reduce this radiation exposure, we developed a protective method that can be used during endoscopic lumbar spine surgery. The purpose of the study was to determine the effectiveness of this method.

METHODS

A prospective interventional study was performed, in which the primary outcome was radiation exposure to the surgeon [Sievert (Sv)] per case. This was measured using a radiation badge at the levels of the neck, chest, and abdomen on the surface of a protector for the surgeon in 18 endoscopic lumbar spine surgeries, including 9 each with the radiation protection method and the conventional method. Data were also collected for age, gender, body mass index, operative side, and total fluoroscopy time. Primary outcomes were compared in cases that used the radiation protection method and the conventional method.

RESULTS

The mean radiation exposures to the surgeon at the neck, chest, and abdomen were 1.0, 0.8 and 0.7 µSv, respectively, using the radiation protection method, and 3.2, 10.8, and 10.2 µSv, respectively, using the conventional method. The differences in exposure at all three points were significant (P=0.013, P<0.001, P<0.001, respectively).

CONCLUSIONS

These results show the effectiveness of the radiation protection method developed to reduce exposure of the surgeon to radiation during endoscopic lumbar spine surgery.

Effect of physical therapy on early knee osteoarthritis with medial meniscal posterior tear assessed by MRI T2 mapping and 3D-to-2D registration technique: A prospective intervention study

Objectives: The purpose of this study was to verify that exercise aimed at improving knee kinematics in early-stage knee osteoarthritis (OA) patients with medial meniscus posterior root tears (MMPRTs) reduces knee adduction angle during gait and prevents rapid cartilage degeneration in the medial compartment of the knee.Methods: Subjects were randomly assigned to an adapting alignment exercise (AAE) group, with the goal of improving knee kinematics, and a muscle training and exercise (MTE) group. Before the start of the six-month intervention and following its completion, we performed an analysis of knee kinematics during gait using a 3D-to-2D registration technique and identified the area of cartilage degeneration using MRI T2 mapping.Results: The amount of change between pre- and post-intervention measurements of the maximum angle of adduction was 0.48° (95% CI: -0.14, 1.09) in the MTE group and -0.40° (-0.84, 0.04) in the AAE group (p = .039). The amount of change in the area of cartilage degeneration according to MRI T2 mapping expressed as MTE/AAE group was 7.7 mm² (-0.4, 15.8)/-2.7 mm² (-10.8, 5.3) at the posterior knee (p = .043).Conclusion: AAE could be a potential treatment method that improves the natural course of knee OA with MMRPTs.

Preoperative Design for the Posterolateral Approach in Full-Endoscopic Spine Surgery for the Treatment of L5/S1 Lumbar Disc Herniation

OBJECTIVE

Full-endoscopic spine surgery (FESS) is a relatively less invasive treatment for lumbar disc herniation (LDH). This study investigated the optimal operative route of the posterolateral approach (PLA) of FESS for the treatment of L5/S1 LDH.

METHODS

Between June 2016 and November 2018, a total of 21 patients with leg pain due to L5/S1 LDH underwent PLA of FESS. According to the partial removal of the superior articular process (SAP) of the L5/S1 facet joint (FJ), we categorized these patients into 2 groups. LDH type, anatomical configurations (FJ, sacral ala [SA], and iliac crest [IC]), the presence or absence of spondylolysis, operation time, and operative outcome were compared between these 2 groups.

RESULTS

Although the anatomical configuration of the FJ was the most important factor for the necessity of SAP removal, the configuration of the SA and IC did not restrict endoscope insertion and subsequent LDH removal. Even in intracanal LDH, the removal of SAP was not absolutely required depending on the FJ configuration. Furthermore, the presence of spondylolysis was a factor associated with the unnecessity of SAP removal.

CONCLUSION

Detailed radiological examination of the FJ configuration is an important preoperative investigation to determine the optimal operative route for PLA of FESS.

Successful treatment of lumbar ligamentum flavum hematoma using a spinal full-endoscopic system

Background

Percutaneous endoscopic lumbar discectomy (PELD) is a relatively less invasive treatment for lumbar disc herniation (LDH). This study investigated the usefulness of a full-endoscopic system for PELD in lumbar ligamentum flavum hematoma (LFH) treatment.

Methods

Between May 2017 and Jun 2018, a total of five patients with leg pain due to LFH underwent surgery using a full-endoscopic system for PELD. A percutaneous endoscopic translaminar approach (PETA) was performed right above the LFH. Pathological examination of the hematoma capsule was performed in all cases.

Results

The mean age of the patients was 64 years; there were 3 male and 2 female patients. Leg pain improved immediately after operation in all cases. Intraoperative findings and pathological examination revealed that the synovium at adjacent facet joints was not involved.

Conclusions

Full-endoscopic system is not only a safe and effective minimally invasive system for the treatment of lumbar LFH, but is also superior to acquire a correct diagnosis.

A less invasive surgery using a full-endoscopic system for L5 nerve root compression caused by lumbar foraminal stenosis

Background

Percutaneous endoscopic lumbar discectomy (PELD) is a relatively less invasive treatment for lumbar disc herniation (LDH). This study investigated the usefulness of a full-endoscopic system for PELD to treat L5 nerve root compression caused by lumbar foraminal stenosis (L5-LFS).

Methods

Between November 2016 and December 2017, a total of 10 patients with unilateral leg pain due to L5-LFS underwent surgery using a full-endoscopic system for PELD. Patients with bilateral L5-LFS or L5-LFS with coexisting LDH and/or spondylolysis were excluded from this study. A percutaneous endoscopic translaminar approach (PETA) was performed via the ipsilateral vertebral isthmus using a 3.5-mm diameter high-speed drill. Preoperative and postoperative statuses were evaluated using the modified Japanese Orthopedic Association (mJOA) and Numerical Rating Scale (NRS) scores.

Results

The patients' mean age was 62.2 years; there were 7 male and 3 female patients. The mean recovery rate was 58.2% with the mJOA score; mean pre- and postoperative NRS scores were 7.4 and 2.3, respectively. The mean operative time was 77.6 min. Although there were no major complications, pain did not improve in an 80-year-old woman with coexisting spondylolisthesis (Meyerding grade 2).

Conclusions

PETA using a full-endoscopic system is a safe and effective minimally invasive treatment for L5-LFS, with potential to be an alternative surgical strategy for L5-S1 interbody fusion.

Risk factors for surgical site infection after lumbar laminectomy and/or discectomy for degenerative diseases in adults: A prospective multicenter surveillance study with registry of 4027 cases

Surgical site infection (SSI) is a significant complication after spinal surgery and is associated with increased hospital length of stay, high healthcare costs, and poor patient outcomes. Accurate identification of risk factors is essential to develop strategies to prevent wound infections. The aim of this prospective multicenter study was to determine the independent factors associated with SSI in posterior lumbar surgeries without fusion (laminectomy and/or herniotomy) for degenerative diseases in adult patients. From July 2010 to June 2014, we conducted a prospective multicenter surveillance study in adult patients who developed SSI after undergoing lumbar laminectomy and/or discectomy in ten participating hospitals. Detailed patient and operative characteristics were prospectively recorded using a standardized data collection format. SSI was based on the Centers for Disease Control and Prevention definition. A total of 4027 consecutive adult patients were enrolled, of which 26 (0.65%) developed postoperative SSI. Multivariate regression analysis indicated two independent factors. An operating time >2 h (P = 0.0095) was a statistically significant independent risk factor, whereas endoscopic tubular surgery (P = 0.040) was a significant independent protective factor. Identification of these associated factors may contribute to surgeons’ awareness of the risk factors for SSI and could help counsel the patients on the risks associated with lumbar laminectomy and/or discectomy. Furthermore, this study’s findings could be used to develop protocols to decrease SSI risk. To the best of our knowledge, this is the first prospective multicenter study that identified endoscopic tubular surgery as an independent protective factor against SSI after lumbar posterior surgery without fusion.

Percutaneous endoscopic lumbar discectomy via adjacent interlaminar space for highly down-migrated lumbar disc herniation: a technical report

The treatment of highly migrated lumbar disc herniation (LDH) is a challenge for percutaneous endoscopic lumbar discectomy (PELD). The purpose of this study was to determine the feasibility and efficacy of PELD for highly migrated LDH via the adjacent interlaminar space. We performed PELD via the adjacent interlaminar space in three patients with radiculopathy caused by highly migrated LDH using a full-endoscopic system (diameter of working channel: 4.1 mm, outer diameter: 6.9 mm). One case had a large interlaminar bone window that did not require enlargement. Enlargement of the bone window in other cases was performed with a 3.5-mm diameter high-speed drill. After the operation, we confirmed pain relief and evacuation of migrated LDH on magnetic resonance imaging in all patients. The mean operative time was 75.3 min, and no complication was observed. PELD via the adjacent interlaminar space is an appropriate operative approach for highly down-migrated LDH. Minimal laminectomy using a high-speed drill is conductive to this approach.

Microendoscope-assisted posterior lumbar interbody fusion: a technical note

Background

Various surgical options for lumbar interbody fusion have been reported. Minimally invasive techniques are widely used to reduce soft tissue damage. Here, we report our novel technique of microendoscope-assisted posterior lumbar interbody fusion (ME-PLIF) using an 18-mm tubular retractor system (METRx, Medtronic Sofamor Danek, Memphis, TN, USA) for lumbar spine degeneration treatment.

Methods

Between January 2011 and December 2011, 48 patients underwent one level ME-PLIF by a surgeon in our hospital. We followed up 46 patients (95.8%). A 20-mm skin incision was made in the craniocaudal direction at the level of the intervertebral disc, 15 mm outside the midline (symptomatic side). The surgeon placed the tubular retractor and performed decompression, thoroughly discarded the intervertebral disc, and then inserted the autologous crushed bone on the opposite side. Subsequently, a cage was inserted using fluoroscopic guidance. Following the end of the microendoscopic operation, pedicle screws (PS) were inserted percutaneously using fluoroscopic guidance. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and the Japanese Orthopedic Association (JOA) scores. For radiological outcomes, fusion rates based on the Bridwell fusion grading system were evaluated using plain radiography or a computed tomography scan at the most recent follow-up timepoint.

Results

The mean age was 61.4 (range, 36.0-86.0) years, the mean operation time was 102 (range, 59-162) min, and the mean blood loss was 86 (range, small amounts-315) mL. The average pre- and post-operative ODI scores were 22.1 and 9.7, respectively, with an improvement rate of 56.1%, and the pre- and post-operative JOA scores were 9.8 and 16.4, respectively, with an improvement rate of 50%. There were no cases of pseudarthrosis. One case (2.2%) had a deep wound infection that required total removal of the implants. Four (8.7%) cases had a dural tear and required dural sutures under microendoscopy, though they had good recovery.

Conclusions

This technique yielded good results. The advantages of using only the microendoscope were: (I) better visual field and (II) higher operability (it was possible to change the tubular retractor to various angles; this was difficult under direct viewing or under a microscope). These features are considered to lead to reduce soft tissue damage. Although long-term follow-up results are needed, this appears to be a safe and minimally invasive treatment option for lumbar spine degeneration.

Significance and pitfalls of percutaneous endoscopic lumbar discectomy for large central lumbar disc herniation

Background

Percutaneous endoscopic lumbar discectomy (PELD) is a relatively less invasive treatment for lumbar disc herniation (LDH). The present study focused on the transforaminal approach (TFA) and investigated the significance of PELD via this approach for large central LDH.

Methods

LDH that did not show cerebrospinal fluid (CSF) on axial T2-weighted magnetic resonance images was defined as large central LDH. PELD via the TFA was performed in 11 patients with large central LDH. Pre- and post-operative statuses were evaluated using the modified Japanese Orthopedic Association (mJOA) and Numerical Rating Scale (NRS) scores.

Results

The patients' mean age was 44.1 years; there was single-level involvement, mostly at L4/5 (seven cases). The mean recovery rate of the mJOA score was 48.7%, and mean pre- and post-operative NRS scores were 7.1 and 1.5, respectively. The mean operative time was 38.1 min. Although there were no major complications, the dura was accidentally punctured at the initial operative step for discography in one case. LDH recurred in one case at 5 months after the operation, and the patient was treated by PELD via the TFA on the contralateral side.

Conclusions

The TFA for PELD is a safe, minimally invasive, effective treatment for large central LDH. However, the operator should pay attention to malpositioning of the flat and laterally expanded dural sac.

Anatomical relation between the accessory process and pedicle in the lumbar vertebrae

The pedicle screw is one of the most common medical devices used in spinal surgery. Although there are well-established insertion points based on anatomical landmarks, such as the mammillary process and the transverse process, morphological data on the relationship between the accessory process and the pedicle are still scarce. To clarify this relationship, we recruited 50 cases of hernia of lumbar intervertebral disc, diagnosed using three-dimensional computed tomography of the lumbar vertebrae. We identified the pedicle isthmus in a transverse plane parallel to the upper endplate and measured the angles and distances from the tip of the accessory process to the intersection points at the medial or lateral surface, or at the midpoint between the two intersection points. In a sagittal plane showing the pedicle isthmus, we measured the wedging angle of the vertebral body as well as the angle from the tip of accessory process to the posterior edge of the upper endplate of vertebral body, or to the lower end of the pedicle root. We found that from the tip of the accessory process passing through the pedicle isthmus, a line should be directed 20 (± 6.6) degrees medially in the transverse plane and 5 (± 4.3) degrees cranially in the sagittal plane. This distance from the tip of the accessory process to the isthmus was 1.5 (± 0.3) cm. Our study provides a new anatomical basis for the use of the accessory process as a landmark for insertion of the pedicle screw.

A comparative study of three conservative treatments in patients with lumbar spinal stenosis: lumbar spinal stenosis with acupuncture and physical therapy study (LAP study)

Background

Although the efficiency of conservative management for lumbar spinal stenosis (LSS) has been examined, different conservative management approaches have not been compared. We have performed the first comparative trial of three types of conservative management (medication with acetaminophen, exercise, and acupuncture) in Japanese patients with LSS.

Methods

Patients with L5 root radiculopathy associated with LSS who visited our hospital for surgical treatment were enrolled between December 2011 and January 2014. In this open-label study, patients were assigned to three treatment groups (medication, exercise, acupuncture) according to the visit time. The primary outcomes were Zurich claudication questionnaire (ZCQ) scores before and after 4 weeks of treatment. Least square mean analysis was used to assess the following dependent variables in the treatment groups: changes in symptom severity and physical function scores of the ZCQ and the ZCQ score of patient’s satisfaction after treatment.

Results

Thirty-eight, 40, and 41 patients were allocated to the medication, exercise, and acupuncture groups, respectively. No patient underwent surgical treatment during the study period. The symptom severity scores of the ZCQ improved significantly after treatment in the medication (p = 0.048), exercise (p = 0.003), and acupuncture (p = 0.04) groups. The physical function score improved significantly in the acupuncture group (p = 0.045) but not in the medication (p = 0.20) and exercise (p = 0.29) groups. The mean reduction in the ZCQ score for physical function was significantly greater for acupuncture than for exercise. The mean ZCQ score for treatment satisfaction was significantly greater for acupuncture than for medication.

Conclusions

Acupuncture was significantly more effective than physical exercise according to the physical function score of the ZCQ and than medication according to the satisfaction score. The present study provides new important information that will aid decision making in LSS treatment.

Trial registration

This study was registered with the UMIN Clinical Trials Registry (UMIN000006957).

Risk factors for incidental durotomy during posterior open spine surgery for degenerative diseases in adults: A multicenter observational study

Incidental durotomy (ID) is a common intraoperative complication of spine surgery. It can lead to persistent cerebrospinal fluid leakage, which may cause serious complications, including severe headache, pseudomeningocele formation, nerve root entrapment, and intracranial hemorrhage. As a result, it contributes to higher healthcare costs and poor patient outcomes. The purpose of this study was to clarify the independent risk factors that can cause ID during posterior open spine surgery for degenerative diseases in adults. We conducted a prospective multicenter study of adult patients who underwent posterior open spine surgery for degenerative diseases at 10 participating hospitals from July 2010 to June 2013. A total of 4,652 consecutive patients were enrolled. We evaluated potential risk factors, including age, sex, body mass index, American Society of Anesthesiologists physical status classification, the presence of diabetes mellitus, the use of hemodialysis, smoking status, steroid intake, location of the surgery, type of operative procedure, and past surgical history in the operated area. A multivariate logistic regression analysis was performed to identify the risk factors associated with ID. The incidence of ID was 8.2% (380/4,652). Corrective vertebral osteotomy and revision surgery were identified as independent risk factors for ID, while cervical surgery and discectomy were identified as factors that independently protected against ID during posterior open spine surgery for degenerative diseases in adults. Therefore, we identified 2 independent risk factors for and 2 protective factors against ID. These results may contribute to making surgeons aware of the risk factors for ID and can be used to counsel patients on the risks and complications associated with open spine surgery.

Clinical evaluation of microendoscopy-assisted extreme lateral interbody fusion

BACKGROUND

Extreme lateral interbody fusion (XLIF) has rapidly become a popular operative procedure for lumbar canal stenosis and scoliosis. This approach provides direct access to the lateral aspect of the disc with minimal disruption of spinal structures, including ligaments and muscles. However, it involves risk of injuries to the lumbar nerve plexus, segmental artery and intestinal tract because of the limited surgical field. This study aimed to clarify the benefit of using a microendoscope to prevent these injuries.

METHODS

A total of 96 consecutive patients treated by a single surgeon were retrospectively analyzed. The basic approach via the psoas muscle was performed in accordance with the conventional XLIF procedure. Operative manipulations, such as insertion of the shim, discectomy, endplate preparation and intervertebral spacer placement, were performed with the assistance of a microendoscope. Preoperative and postoperative neurological status were evaluated using the Japanese Orthopedic Association (JOA) scores and the Oswestry Disability Index (ODI).

RESULTS

Eighty-four patients underwent surgery for a single vertebral level, nine patients underwent surgery for 2 levels and three patients underwent surgery for 3 levels (average, 1.2 levels). The average age of patients was 61 years (range, 22-83 years); the mean follow-up period was 18 months (range, 3-36 months). Average preoperative and postoperative JOA scores were 11.9 and 15.6, with a mean recovery rate of 33%. Average preoperative and postoperative ODI scores were 38.6 and 19.1. There were 3 (3.1%) complications: 2 end-plate fractures and 1 deep surgical site infection. There were no bowel perforations or vascular injuries.

CONCLUSIONS

Microendoscopy assistance is one solution for severe visceral and vascular injuries related to XLIF.

Different operative findings of cases predicted to be symptomatic discal pseudocysts after percutaneous endoscopic lumbar discectomy

Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive treatment for lumbar disc herniation (LDH). This report focused on one of the rare complications of PELD: symptomatic postoperative discal pseudocyst (PDP). A 27-year-old male patient (case 1) presented with recurrent radiculopathy in his left leg. Twenty days previously, he had undergone PELD for left L4/5 LDH and his symptoms temporarily improved. A 14-year-old female patient (case 2) also developed recurrent pain in her left leg. Thirty days previously, she had undergone PELD for left L4/5 LDH and her symptoms disappeared. On the basis of the finding of an expandable round lesion at the evacuated sites of LDH on magnetic resonance imaging (MRI), with low intensity of T1-weighted imaging and high intensity on T2-weighted imaging, we predicted symptomatic PDP in both cases. Given the progressive leg pain in both cases, surgical treatments were adopted (case 1: microendoscopic discectomy, case 2: PELD). During the operation, we confirmed that case 1 was a simple recurrence of LDH and case 2 was symptomatic PDP. Previous studies on symptomatic PDP included cases diagnosed without operative findings. Therefore, it should be carefully considered that such cases might be a simple recurrence of LDH.

Anterior cage dislodgement in posterior lumbar interbody fusion: a review of 12 patients

OBJECTIVE Interbody fusion cages are widely used to achieve initial fixation and secure spinal fusion; however, there are certain technique-related complications. Although anterior cage dislodgement can cause major vascular injury, the incidence is extremely rare. Here, the authors performed a review of anterior cage dislodgement following posterior lumbar interbody fusion (PLIF) surgery. METHODS The authors retrospectively reviewed the cases of 4625 patients who had undergone PLIF at 6 institutions between December 2007 and March 2015. They investigated the incidence and causes of surgery-related anterior cage dislodgement, salvage mechanisms, and postoperative courses. RESULTS Anterior cage dislodgement occurred in 12 cases (0.26%), all of which were caused by technical errors. In 9 cases, excessive cage impaction resulted in dislodgement. In 2 cases, when the cage on the ipsilateral side was inserted, it interacted and pushed out the other cage on the opposite side. In 1 case, the cage was positioned in an extreme lateral and anterior part of the intervertebral disc space, and it postoperatively dislodged. In 3 cases, the cage was removed in the same operative field. In the remaining 9 cases, CT angiography was performed postoperatively to assess the relationship between the dislodged cage and large vessels. Dislodged cages were conservatively observed in 2 cases. In 7 cases, the cage was removed because it was touching or compressing large vessels, and an additional anterior approach was selected. In 2 patients, there was significant bleeding from an injured inferior vena cava. There were no further complications or sequelae associated with the dislodged cages during the follow-up period. CONCLUSIONS Although rare, iatrogenic anterior cage dislodgement following a PLIF can occur. The authors found that technical errors made by experienced spine surgeons were the main causes of this complication. To prevent dislodgement, the surgeon should be cautious when inserting the cage, avoiding excessive cage impaction and ensuring cage control. Once dislodgement occurs, the surgeons must immediately address this difficult complication. First, the possibility of a large vessel injury should be considered. If the patient's vital signs are stable, the surgeon should continue with the surgery without cage removal and perform CT angiography postoperatively to assess the cage location. Blind maneuvers should be avoided when the surgical site cannot be clearly viewed. When the cage compresses or touches the aortic artery or vena cava, it is better to remove the cage to avoid late-onset injury to major vessels. When the cage does not compress or touch vessels, its removal is controversial. The risk factors associated with performing another surgery should be evaluated on a case-by-case basis.

Consideration of proper operative route for interlaminar approach for percutaneous endoscopic lumbar discectomy

BACKGROUND

Percutaneous endoscopic lumbar discectomy (PELD) is one of the less invasive treatments of lumbar disc herniation (LDH), and has three different operative approaches. This study focused on the interlaminar approach (ILA) and investigated the appropriate operative route for this approach.

METHODS

ILA was performed in 41 patients with LDH. The width of the interlaminar space, LDH size, and positional relation between LDH and the corresponding nerve root were radiologically evaluated. Thirty-three LDHs were removed via the shoulder of the corresponding nerve root and eight were removed via the axilla of the corresponding nerve root and dural sac. Pre- and postoperative status were evaluated using the modified Japanese Orthopedic Association (mJOA) and numerical rating scale (NRS) scores.

RESULTS

The mean age was 41.5 years; there was single-level involvement, mostly at L5/S1 (33 cases). The mean recovery rate of mJOA score was 59.8% and mean pre- and postoperative NRS scores were 5.8 and 0.98, respectively. Relatively severe complications developed in three patients treated by ILA via the shoulder. There was persistent numbness in the corresponding nerve area, transient muscular weakness, and transient bladder and rectal disturbance, may be due to excessive compression of the nerve root and/or dural sac by the endoscopic sheath.

CONCLUSIONS

ILA can be used to treat LDH revealing an interlaminar space of ≥20 mm. The procedure is minimally invasive and effective; however, appropriate selection of an operative route is important to avoid operative complications. Particularly for large LDH, the operative route via the axilla should be considered.

Diagnosing Discogenic Low Back Pain Associated with Degenerative Disc Disease Using a Medical Interview

Purposes

To evaluate the usefulness of our original five questions in a medical interview for diagnosing discogenic low back pain (LBP), and to establish a support tool for diagnosing discogenic LBP.

Materials and Methods

The degenerative disc disease (DDD) group (n = 42) comprised patients diagnosed with discogenic LBP associated with DDD, on the basis of magnetic resonance imaging findings and response to analgesic discography (discoblock). The control group (n = 30) comprised patients with LBP due to a reason other than DDD. We selected patients from those who had been diagnosed with lumbar spinal stenosis and had undergone decompression surgery without fusion. Of them, those whose postoperative LBP was significantly decreased were included in the control group. We asked patients in both groups whether they experienced LBP after sitting too long, while standing after sitting too long, squirming in a chair after sitting too long, while washing one’s face, and in the standing position with flexion. We analyzed the usefulness of our five questions for diagnosing discogenic LBP, and performed receiver operating characteristic (ROC) curve analysis to develop a diagnostic support tool.

Results

There were no significant differences in baseline characteristics, except age, between the groups. There were significant differences between the groups for all five questions. In the age-adjusted analyses, the odds ratios of LBP after sitting too long, while standing after sitting too long, squirming in a chair after sitting too long, while washing one’s face, and in standing position with flexion were 10.5, 8.5, 4.0, 10.8, and 11.8, respectively. The integer scores were 11, 9, 4, 11, and 12, respectively, and the sum of the points of the five scores ranged from 0 to 47. Results of the ROC analysis were as follows: cut-off value, 31 points; area under the curve, 0.92302; sensitivity, 100%; and specificity, 71.4%.

Conclusions

All five questions were useful for diagnosing discogenic LBP. We established the scoring system as a support tool for diagnosing discogenic LBP.

Advantages and disadvantages of posterolateral approach for percutaneous endoscopic lumbar discectomy

BACKGROUND

Percutaneous endoscopic lumbar discectomy (PELD) is one of the less invasive treatments for lumbar disc herniation (LDH), and has 3 different operative approaches. This study focused on the posterolateral approach (PLA) and investigated the appropriate operative indication.

METHODS

PLA was performed in 29 patients with foraminal and extraforaminal LDH. The height and width of the foramen, LDH type, and positional relationship between LDH and the foramen were radiologically evaluated. Foraminoplasty was also performed in 12 cases including those combined with intra-canal LDH or osseous foraminal stenosis. Pre- and postoperative status was evaluated using Numerical Rating Scale (NRS) scores.

RESULTS

Patient mean age was 56.8 years; there was single-level involvement at L3/4 (13 cases) and at L4/5 (13 cases). The mean pre- and postoperative NRS scores were 6.1 and 1.8, respectively. Early recurrence developed in a patient who was found to have local scoliosis at the corresponding vertebral level.

CONCLUSIONS

PLA can be safely used to treat foraminal and extraforaminal LDH with foraminal height ≥13 mm and foraminal width ≥7 mm. The procedure is effective for preserving the facet joint; however, we should carefully consider the indications when local scoliosis and/or instability are present.