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.

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.

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.

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.

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.

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.

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.

Partial Resection of Spinous Process for the Elderly Patients with Thoraco-Lumbar Kyphosis: Technical Report.

Background and objectives: Global sagittal imbalance with lumbar hypo-lordosis can cause low back pain (LBP) during standing and/or walking. This condition has recently been well-known as one of the major causes of reduced health-related quality of life (HRQOL) in elderly populations. Decrease in disc space of anterior elements and an increase in the spinous process height of posterior elements may both contribute to the decrease in lordosis of the lumbar spine. To correct the sagittal imbalance, the mainstream option is still a highly invasive surgery, such as long-segment fusion with posterior wedge osteotomy. Therefore, we developed a treatment that is partial resection of several spinous processes of thoraco-lumbar spine (PRSP) and lumbar extension exercise to improve the flexibility of the spine as postoperative rehabilitation. Materials and Methods: Consecutively, seven patients with over 60 mm of sagittal vertical axis (SVA) underwent PRSP. The operation was performed with several small midline skin incisions under general anesthesia. After splitting the supraspinous ligaments, the cranial or caudal tip of the spinous process of several thoraco-lumbar spines was removed, and postoperative rehabilitation was followed to improve extension flexibility. Results: The average follow-up period was 13.0 months. The average blood loss and operation time were 11.4 mL and 47.4 min, respectively. The mean SVA improved from 119 to 93 mm but deteriorated in one case. The mean numerical rating scale of low back pain improved from 6.6 to 3.7 without any exacerbations. The mean Oswestry Disability Index score was improved from 32.4% to 19.1% in six cases, with one worsened case. Conclusions: We performed PRSP and lumbar extension exercise for the patients with LBP due to lumbar kyphosis. This minimally invasive treatment was considered to be effective in improving the symptoms of low back pain and HRQOL, especially of elderly patients with lumbar kyphosis.

Microendoscope-Assisted Versus Open Posterior Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Multicenter Retrospective Cohort Study.

Background and objectives: Minimally invasive surgery has become popular for posterior lumbar interbody fusion (PLIF). Microendoscope-assisted PLIF (ME-PLIF) utilizes a microendoscope within a tubular retractor for PLIF procedures; however, there are no published reports that compare Microendoscope-assisted to open PLIF. Here we compare the surgical and clinical outcomes of ME-PLIF with those of open PLIF. Materials and Methods: A total of 155 consecutive patients who underwent single-level PLIF were registered prospectively. Of the 149 patients with a complete set of preoperative data, 72 patients underwent ME-PLIF (ME-group), and 77 underwent open PLIF (open-group). Clinical and radiographic findings collected one year after surgery were compared. Results: Of the 149 patients, 57 patients in ME-group and 58 patients in the open-group were available. The ME-PLIF procedure required a significantly shorter operating time and involved less intraoperative blood loss. Three patients in both groups reported dural tears as intraoperative complications. Three patients in ME-group experienced postoperative complications, compared to two patients in the open-group. The fusion rate in ME-group at one year was lower than that in the open group (p = 0.06). The proportion of patients who were satisfied was significantly higher in the ME-group (p = 0.02). Conclusions: ME-PLIF was associated with equivalent post-surgical outcomes and significantly higher rates of patient satisfaction than the traditional open PLIF procedure. However, the fusion rate after ME-PLIF tended to be lower than that after the traditional open method.

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.

Chemonucleolysis with Chondroitin Sulfate ABC Endolyase for Treating Lumbar Disc Herniation: Exploration of Prognostic Factors for Good or Poor Clinical Outcomes.

Background and Objectives: Chondroitin sulfate ABC endolyase (condoliase) was launched as a new drug for chemonucleolysis in 2018. Few studies assessed its clinical outcomes, and many important factors remain unclear. This study aimed to clarify the preoperative conditions in which condoliase could be highly effective. Materials and Methods: Of 47 patients who received condoliase, 34 were enrolled in this study. The mean age of the patients was 33 years. The average duration since the onset of disease was 8.6 months. We evaluated patients' low back and leg pain using a numerical rating scale (NRS) score at two time points (before therapy and 3 months after therapy). We divided the patients into two groups (good group (G): NRS score improvement ≥ 50%, poor group (P): NRS score improvement < 50%). The parameters evaluated were age, disease duration, body mass index (BMI), and positive or negative straight leg raising test results. In addition, the loss of disc height and preoperative radiological findings were evaluated. Results: In terms of low back and leg pain, the G group included 9/34 (26.5%) and 21/34 (61.8%) patients, respectively. Patients' age (low back pain G/P, 21/36.5 years) was significantly lower in the G group for low back pain (p = 0.001). High-intensity change in the protruded nucleus pulposus (NP) and spinal canal occupancy by the NP ≥ 40% were significantly high in those with leg pain in the G groups (14/21, p = 0.04; and 13/21, p = 0.03, respectively). Conclusions: The efficacy of improvement in leg pain was significantly correlated with high-intensity change and size of the protruded NP. Condoliase was not significantly effective for low back pain but could have an effect on younger patients.

Full-Endoscopic Lumbar Interbody Fusion for Treating Lumbar Disc Degeneration Involving Disc Height Loss: Technical Report.

Background and Objectives: Lumbar disc degeneration (LDD) is the main cause of lower back pain and leads to corresponding disc height loss. Although lumbar interbody fusion (LIF) is commonly used for treating LDD, several different treatment strategies are available. We performed a minimally invasive full-endoscopic LIF (FELIF) using a uniportal full-endoscopic system. Materials and Methods: FELIF was performed for 12 patients with LDD with disc-height loss using a 4.1 mm working channel endoscope and a newly developed slider for cage insertion. The mean age of the patients was 68.3 years; the patients presented with single vertebral level involvement. The Brandner's disc index was used for evaluating the postoperative increase in the disc height. Preoperative and postoperative leg pain was evaluated using the numerical rating scale (NRS) score. Results: The mean operation time for FELIF was 109.4 min. The mean duration of hospital stay after FELIF was 7.7 days. There were no operative and postoperative complications, even without drainage during the mean follow-up period of 6.2 months (range, 2-10 months). The Brandner's disc index improved statistically significant (p > 0.01). The mean preoperative and postoperative NRS scores were 6.5 and 1.2, respectively. Conclusions: FELIF using a 4.1 mm working channel endoscope can be used for treating LDD with disc height loss. Radiculopathy caused by foraminal stenosis was the most suitable operative indication for FELIF.

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.

Comparative Study between Full-Endoscopic Discectomy and Microendoscopic Discectomy for the Treatment of Lumbar Disc Herniation.

Background and objectives: Lumbar disc herniation (LDH) is a common disease in the meridian of life. Although surgical discectomy is commonly used to treat LDH, there are several different strategies. We compared the outcomes of uniportal full-endoscopic discectomy (FED) with those of microendoscopic discectomy (MED) in treating LDH. Materials and Methods: FED was performed using a 4.1-mm working channel endoscope, and MED was performed using a 16-mm diameter tubular retractor and endoscope. Data of patients with LDH treated with FED (n = 39) or MED (n = 27) by the single surgeon were retrospectively reviewed. Patient background information and operative data were collected. Pre- and postoperative low back and leg pain were evaluated using the numerical rating scale (NRS) score. Pre- and postoperative disc height index (DHI) values were calculated from plain radiographs, and the disc height loss was evaluated using the ratio (DHI ratio); Results: The median (interquartile range (IQR) Q25-75) operation times for FED and MED were 42 (33-61) and 43 (33-50) minutes, respectively. The median (IQR Q25-75) pre- and postoperative NRS scores for low back pain were 5 (2-7) and 1 (0-4), respectively, for FED and 6 (3-8) and 1 (0-2), respectively, for MED. The median (IQR Q25-75) pre- and postoperative NRS scores for leg pain were 7 (5-8) and 0 (0-2), respectively, for FED and 6 (5-8) and 0 (0-2), respectively, for MED. These data were not different between the FED and MED groups. The median (IQR Q25-75) DHI ratios of FED and MED were 0.94 (0.89-1.03) and 0.90 (0.79-0.95), respectively. The DHI ratio was significantly higher (p < 0.05) in the FED group than in the MED group, and there was less blood loss; Conclusions: The pain-relieving effect of FED in treating LDH was almost identical to that of MED. However, FED was superior to MED in preventing disc height loss, which is one of the indicators of postoperative disc degeneration.

A Comparative Study on the Minimal Invasiveness of Full-Endoscopic and Microendoscopic Cervical Foraminotomy Using Intraoperative Motor Evoked Potential Monitoring.

Background and Objectives: Full-endoscopic cervical foraminotomy (FECF) and microendoscopic cervical foraminotomy (MECF) are effective surgeries for cervical radiculopathy and are considered minimally invasive in terms of damage to paraspinal soft tissue. However, no studies have quantitatively compared FECF and MECF in terms of neurological invasiveness. The aim of this study was to compare the neurological invasiveness of FECF and MECF using intraoperative motor evoked potential (MEP) monitoring. Materials and Methods: A chart review was conducted of 224 patients with cervical radiculopathy who underwent FECF or MECF between April 2014 and March 2020. Patients were 37 women and 187 men, with a mean age of 51 (range, 21-86) years. FECF was performed in 143 cases and MECF was performed in 81 cases. Results: Average MEP amplitude significantly increased from 292 mV before to 677 mV after nerve root decompression in patients who underwent the FECF. The average improvement rate was 273%. In patients who underwent the MECF, average MEP amplitude significantly increased from 306 mV before to 432 mV after nerve root decompression. The average improvement rate was 130%. The improvement rate was significantly higher for FECF compared with MECF. Conclusions: MEP amplitude increased after nerve root decompression in both FECF and MECF, but the improvement rate was higher in FECF. These results suggest that FECF might be more minimally invasive than MECF in terms of neurological aspects.

Factors related to subjective satisfaction following microendoscopic foraminotomy for cervical radiculopathy.

BACKGROUND: Microendoscopic foraminotomy has been reported to be effective for the treatment of cervical radiculopathy, using outcome measurement scores such as the neck disability index (NDI) and numerical rating scale (NRS). However, the scores for spine surgery do not always reflect the true subjective satisfaction of the patient. The purpose of this study was to evaluate factors related to subjective satisfaction following microendoscopic foraminotomy for cervical radiculopathy. METHODS: The subjects consisted of consecutive patients who underwent microendoscopic foraminotomy for cervical radiculopathy. Patient background information and operative data were collected. The NDI, the NRS score for the neck, upper back, and arm, and the EuroQOL-5D (EQ-5D) were assessed preoperatively and 1 year postoperatively. Postoperative subjective satisfaction was also assessed as a direct evaluation of satisfaction, and willingness to undergo the same operation if needed was assessed as an indirect evaluation. RESULTS: A total of 42 patients were included in this study. The mean age was 52.9 ± 11.8 years; 19.0% were female and 81.0% were male. The operation time for one level was 57.7 min and the estimated blood loss was minimal in most cases. All NDI, NRS, and EQ-5D scores improved significantly postoperatively. Univariate analyses revealed that the factors related to subjective satisfaction were younger age, non-smoking status, high preoperative NDI score, and low postoperative NRS score for the arm. Factors related to the willingness to undergo the same operation if needed were high preoperative NDI scores, high preoperative NRS scores for the arm, and low preoperative EQ-5D scores. CONCLUSIONS: Factors related to subjective satisfaction following microendoscopic foraminotomy include younger age, non-smoking status, high preoperative NDI score, high preoperative NRS score for the arm, low preoperative EQ-5D score, and a low postoperative NRS score for the arm.

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 ).

Microendoscopic posterior decompression for the treatment of thoracic myelopathy caused by ossification of the ligamentum flavum: a technical report.

PURPOSE: Ossification of the ligamentum flavum (OLF) is a common cause of progressive thoracic myelopathy in East Asia. Good surgical results are expected for patients who already show myelopathy. Surgical decompression using a posterior approach is commonly used to treat OLF. This study investigated the use of microendoscopic posterior decompression for the treatment of thoracic OLF. METHODS: Microendoscopic posterior decompression was performed on 9 patients with myelopathy. Patients had a mean age of 59.8 years and single-level involvement, mostly at the T10-11 and T11-12 vertebrae. Computed tomography and magnetic resonance imaging were used to classify the OLF. A tubular retractor and endoscopic system were used for microendoscopic posterior decompression. Midline and unilateral paramedian approaches were performed in 2 and 7 patients, respectively. Intraoperative motor evoked potentials (MEPs) of 7 patients were monitored. Pre- and postoperative neurological status was evaluated using the modified Japanese Orthopaedic Association (mJOA) score. RESULTS: Thoracic OLF for all patients were classed as bilateral type with a round morphology. Improvement of MEPs at least one muscle area was recorded in all patients following posterior decompression. A dural tear in one patient was the only observed complication. The mean recovery rate was 44.9 %, as calculated from mJOA scores at a mean follow-up period of 20 months. CONCLUSIONS: Microendoscopic posterior decompression combined with MEP monitoring can be used to treat patients with thoracic OLF. The optimal surgical indication is OLF at a single vertebral level and of a unilateral or bilateral nature, without comma and tram track signs, and a round morphology.

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.

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.