Comparison of Percutaneous Endoscopic Transforaminal Discectomy, Chemonucleolysis, Microdiscectomy, and Microendoscopic Discectomy for Symptomatic Lumbar Disc Herniation: One-year Follow-up Clinical Results and Disc Degeneration.

This study compared the 1-year clinical outcomes and disc degeneration rates after transforaminal full-endoscopic lumbar discectomy (TF-FED), condoliase injection, open discectomy (OD), and microendoscopic discectomy (MED) for lumbar disc herniation (LDH). In total, 279 patients with LDH were divided into four treatment groups: TF-FED, OD, MED, and condoliase injection. Outcomes were evaluated on the basis of the complication rate, Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), visual analog scale (VAS) scores, and the modified MacNab criteria. Surgical and hospital costs were assessed. Disc degeneration and endplate bone marrow edema were evaluated using magnetic resonance images. The mean postoperative JOABPEQ, VAS, or modified MacNab scores among the four groups had no significant differences. Additionally, the nerve injury or reoperation rate among the TF-FED, OD, and MED groups had no significant difference. However, the reoperation rate with condoliase injection was high because of residual disc herniation. Surgical and hospital costs were lower with condoliase injection and higher with OD and MED than those with TF-FED. With TF-FED and condoliase injection, the Pfirrmann grade progressed, and the disc height was significantly smaller than that with OD and MED. Endplate bone marrow edema was more common with condoliase injection and TF-FED. All groups had good outcomes. TF-FED and condoliase injection may reduce the burden of surgery because they can be performed under local anesthesia with little blood loss and low medical costs but tend to be associated with disc degeneration and endplate bone marrow edema. A randomized controlled study with a larger sample is needed.

Full-Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion: Surgical Technique and Nomenclature.

BACKGROUND: Full-endoscopic lumbar surgery is used for decompression of lumbar spinal canal stenosis. Now, a cage can be inserted through Kambin's triangle for lumbar interbody fusion (LIF). We have been performing full-endoscopic trans-Kambin triangle LIF (KLIF) at our institution since 2018. In this article, we describe this technique and present our results. METHODS: We performed full-endoscopic one-level KLIF in 10 patients. The procedure is as follows. First, percutaneous pedicle screws are inserted. Listhesis is reduced if necessary. The endoscope is inserted in Kambin's triangle. Next, the superior articular process is partially removed, enlarging Kambin's triangle to allow safe insertion of the cage. A cannula is inserted into the disk to avoid damaging the exiting nerve. The disk material is shaved and curetted. Finally, the harvested bone is packed in a cage and inserted into the disk space. We analyze the complications, visual analog scores (VAS), and MacNab's criteria. RESULTS: One patient had an irritation in the exiting nerve at L4-L5. The VAS for back pain and leg pain decreased from 69 to 9 and from 60 to 9, respectively. The clinical outcome was considered excellent in eight and good in two patients. CONCLUSIONS: Kambin's triangle lies immediately behind the psoas major. Therefore, we consider KLIF as a lateral LIF procedure comparable with oblique or extreme LIF. However, unlike oblique or extreme LIF, there are no major vessels and organs in the surgical field; therefore, KLIF is the safest type of lateral LIF. Furthermore, using the endoscope, we can perform decompression directly using the facetectomy technique.

Early outcomes of transforaminal percutaneous endoscopic lumbar discectomy for high school athletes with herniated nucleus pulposus of the lumbar spine.

There are no reports in the literature on the clinical outcomes of percutaneous endoscopic lumbar discectomy (PELD) for high school athletes suffering from herniated nucleus pulposus (HNP) of the lumbar spine. PELD is a minimally invasive surgical procedure that can be performed under local anesthesia via an 8-mm skin incision. This study examined the outcomes of transforaminal PELD in high school athletes suffering from HNP. Subjects were 18 patients [14 males and four females; mean age 17 (15-18) years] who underwent PELD at our institutions. The events in which the patients competed were baseball (n = 6), softball (n = 2), rugby (n = 2), basketball (n = 2), table tennis (n = 2), American football (n = 1), wrestling (n = 1), track and field (n = 1), and dance (n = 1). All patients underwent PELD under local anesthesia. Back pain was assessed using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and a visual analog scale (VAS) before and after surgery. Time to return to competitive sport, complications, and rate of recurrence of herniation were examined. All factors assessed by the JOABPEQ were significantly improved after surgery. VAS score was also improved after surgery. Time to return to competitive sport was 7 weeks on average. The rate of return to play was 94.4%. There were no complications, such as dural tear, exiting nerve root injury, or hematoma. One patient had recurrence of HNP. PELD is a promising minimally invasive and effective procedure for high school athletes with HNP.

A Rare Case of Acute-Onset Spastic Quadriparesis Caused by a Chondroma of the Cervical Spine.

Chondromas are benign cartilaginous tumors that occur very rarely in the spine. Moreover, chondromas of the extraskeletal origin are also very rare. In this case report, we describe an extremely rare case of chondroma arising from the ligamentum flavum in the cervical spine. A 67-year-old man presented to our clinic with acute-onset spastic quadriparesis. We performed emergent magnetic resonance imaging and found an epidural mass in the right ligamentum flavum at C4-C5. The acute-onset presentation was suspicious for intraligamentous hematoma in the ligamentum flavum at this level. We performed emergency decompression surgery and en bloc removal of the epidural mass with the right C4 and C5 lamina. The lesion had the appearance of cartilaginous tissue rather than hematoma. Based on the histological investigation, the final diagnosis was intraligamentous chondroma of the cervical spine. The quadriparesis improved postoperatively, as did the results of manual muscle testing in the affected area, and he was able to resume walking independently with a cane. At the one-year follow-up, the manual muscle testing results were almost normal. Surgeons should keep in mind the possibility of benign tumors including chondroma of the cervical spine when a patient presents with acute-onset quadriparesis.

Spontaneous lumbar spinal subdural hematoma: a case report.

Spinal subdural hematoma (SSDH) is an uncommon disease causing acute onset of spinal disorder. Several causes of SSDH have been reported, but reports of spontaneous occurrence of SSDH are limited.

Age-related changes in axial and sagittal orientation of the facet joints: Comparison with changes in degenerative spondylolisthesis.

BACKGROUND: Despite facet joints being three-dimensional structures, previous computed tomography and magnetic resonance imaging studies have evaluated facet joint orientation in only the axial plane. Facet joint orientation in the sagittal plane has rarely been studied using these imaging techniques. The aim of this study was to elucidate facet joint orientation in both the axial and sagittal planes on computed tomography. METHODS: A total of 568 patients (343 men, 225 women) (excluding orthopedic outpatients) for whom abdominal and pelvic computed tomography scans were obtained at our hospital between September 2010 and October 2012 were included. Mean age was 63 (range 21-90) years. Patients were divided into a degenerative spondylolisthesis group (67 patients; 30 men, 37 women) and a control group (313 patients; 313 men, 188 women). Facet joint orientation was evaluated in the control group according to patient age (≤50, 51-60, 61-70, or ≥71 years). The findings in the control group were then compared with those in the degenerative spondylolisthesis group. The orientation of the lumbar facet joints at each level was measured in the axial and sagittal planes on computed tomography images. RESULTS: Facet joint angles decreased with age at L4/5 and L5/S1 in women in the axial plane and at L4/5 in men and L3/4 and L4/5 in women in the sagittal plane. The variation in facet joint angle was greatest at L4/5 in women. Patients with degenerative spondylolisthesis showed more sagittally and horizontally oriented facet joints in the axial and sagittal planes; facet tropism showed an association with degenerative spondylolisthesis in the axial plane. CONCLUSIONS: The axial and sagittal orientation of facet joints in the lower lumbar vertebra, especially L4/5, was negatively correlated with age. This finding could help to explain why older people are more prone to degenerative spondylolisthesis.

Successful Endoscopic Surgery for L5 Radiculopathy Caused by Far-Lateral Disc Herniation at L5-S1 and L5 Isthmic Grade 2 Spondylolisthesis in a Professional Baseball Player.

BACKGROUND: We report the case of a professional baseball player who had severe leg pain due to lumbar lateral disc herniation at L4-5 and isthmic spondylolisthesis at L5 (double crash syndrome). For early recovery to competitive level, we performed minimally invasive endoscopic decompression surgery without fusion. There are few reports to discuss the usefulness of minimally invasive treatment for top athletes. METHODS: A 29-year-old professional baseball player who played catcher was referred to us with a complaint of right leg pain. The previous doctor diagnosed far-lateral disc herniation and Grade 2 isthmic spondylolisthesis and recommended arthrodesis at L5-S1 as treatment for both pathologies. Radiological imaging showed that the right L5 nerve root was impinged by the 2 lumbar disorders, namely, far-lateral disc herniation and a ragged edge around a pars defect. We had taken into account the patient's occupation and his wish to avoid a lengthy sick leave, and we had performed endoscopic decompression surgery during the offseason. The far-lateral disc herniation at L5-S1 was removed under local anesthesia by percutaneous endoscopic discectomy, after which the ragged edge at the pars defect was removed under general anesthesia using a microendoscopic discectomy system. Given that the patient did not have any low back pain, arthrodesis was not considered. RESULTS: The leg pain resolved after surgery. The following year (2015), the patient resumed playing baseball from the beginning of the season and played in 41 games. In the 2016 season, he played in 71 games without any symptoms. No further slippage was observed at radiological follow up 1 year after the surgery. CONCLUSIONS: Minimally invasive endoscopic surgery is an option for radiculopathy in very active patients who need an early return to their previous level of physical activity.

Vertebral Lateral Notch as Optimal Entry Point for Lateral Mass Screwing Using Modified Roy-Camille Technique.

STUDY DESIGN: Retrospective study of 37 consecutive female patients with cervical spondylotic myelopathy who underwent reconstructed computed tomography (CT) scanning of the cervical spine. PURPOSE: The purpose of this study was to investigate whether the vertebral lateral notch of the cervical spine is an effective landmark to determine the entry point for lateral mass screwing. A modified Roy-Camille technique was used to determine the entry point associated with the lateral notch of the cervical spine. OVERVIEW OF LITERATURE: The Roy-Camille technique has been a popular technique for the posterior fixation of the cervical spine. A problem with this technique is determining the entry point on the lateral mass via visual inspection, such as in cases with degenerative or destructive cervical facet joints. METHODS: Thirty-three female patients with cervical spondylotic myelopathy underwent reconstructed CT scanning of the cervical spine. Overall, 132 vertebrae from C3 to C6 were reviewed using reconstructed CT. The probable trajectory using a modified Roy-Camille technique was determined using reconstructed CT scans, and the optimal entry point was identified. Horizontal and vertical distances from the vertebral lateral notch were measured. RESULTS: The entry point determined using the modified Roy-Camille technique was significantly superior and medial compared with that determined using the conventional Roy-Camille technique. At C3 and C4 levels, the entry point using the modified technique was 1.4 mm below and 4.4 mm medial to the lateral notch, and at C5 and C6 levels, it was 2.3 mm below and 4.9 mm medial to the lateral notch. CONCLUSIONS: The vertebral lateral notch of the cervical spine was an effective landmark to determine the entry point for lateral mass screwing. The modified Roy-Camille technique proposed here may prevent surgical complications and poor outcomes.

Prevalence of High-Intensity Zones in the Lumbar Spine According to Age and Their Correlation with Other Degenerative Findings on Magnetic Resonance Imaging.

INTRODUCTION: A high-intensity zone (HIZ) in an intervertebral disc of the lumbar spine is a high-intensity signal located in the posterior annulus fibrosus on T2-weighted magnetic resonance imaging (MRI). There is limited information on the prevalence of HIZ in the lumbar spine according to age. The aim of this cross-sectional study was to investigate the prevalence of HIZ in the lumbar spine by age and the correlation between HIZ and other degenerative findings, such as disc degeneration, disc bulging and herniation, and changes in adjacent vertebral endplates on lumbar MRI. METHODS: We retrospectively reviewed MRI studies of 305 patients (1525 discs) with low back pain, leg pain, or numbness. The prevalence of HIZ was calculated in 5 age groups (<20, 20-39, 40-59, 60-79, 80-91 years). RESULTS: The number of patients in the 5 age groups was 19, 38, 69, 145, and 36, respectively. The prevalence of HIZ in the 5 age groups was 11.8%, 47.3%, 52.2%, 42.8%, and 50.0%, respectively. Disc degeneration was observed in 58.1% and 39.2% of discs with and without HIZ, respectively; disc bulging and herniation was observed in 63.9% and 41.1% and intensity changes at adjacent end plates in 11.6% and 10.0%, respectively. CONCLUSIONS: Prevalence of HIZ from the third decade of life onward was around 50%, with no significant change in prevalence beyond the age of 20 years. HIZ was correlated with disc degeneration, disc bulging, and disc herniation in patients with LBP, leg pain, or numbness.

Morphometric Changes of the Lumbar Intervertebral Foramen after Percutaneous Endoscopic Foraminoplasty under Local Anesthesia.

BACKGROUND: Percutaneous endoscopic diskectomy (PED) for the lumbar spine is a relatively new technique that is becoming more common due to its relatively less invasive nature. However, one possible serious complication is an exiting nerve injury when the cannula of the endoscope is inserted into the neural canal through the intervertebral foramen. A technique to enlarge the intervertebral foramen, called foraminoplasty, was recently established to insert the cannula safely into an appropriate position in the neural canal. METHODS: In this study we performed foraminoplasty during PED under local anesthesia on 15 patients. Using computed tomography scans before and after surgery, the morphometric changes of the intervertebral foramen were evaluated. Surgery-related complications were reviewed. RESULTS: There were 13 men and 2 women, 21 to 86 years of age (mean: 47.1 years). Disk levels were 13 cases at L4-L5, one case at L3-L4, and one case at L5-S1. In 50% of the cases, the mean foraminal area significantly increased from 58.6 mm2 before surgery to 88.4 mm2 after surgery (p < 0.05 by paired t test). The diameter of the foramen was increased at all three points: the lower end plate of the superior vertebrae, the disk, and the upper end plate of the inferior vertebrae. The area increased ∼ 1.5 times, especially at the upper end plate of the inferior vertebrae. In all cases, no exiting nerve injury was encountered during PED. CONCLUSION: Foraminoplasty was an effective method for avoiding exiting nerve root injury during transforaminal PED.

State-of-the-art transforaminal percutaneous endoscopic lumbar surgery under local anesthesia: Discectomy, foraminoplasty, and ventral facetectomy.

Transforaminal (TF) percutaneous endoscopic surgery for the lumbar spine under the local anesthesia was initiated in 2003 in Japan. Since it requires only an 8-mm skin incision and damage of the paravertebral muscles would be minimum, it would be the least invasive spinal surgery at present. At the beginning, the technique was used for discectomy; thus, the procedure was called PELD (percutaneous endoscopic lumbar discectomy). TF approach can be done under the local anesthesia, there are great benefits. During the surgery patients would be in awake and aware condition; thus, severe nerve root damage can be avoided. Furthermore, the procedure is possible for the elderly patients with poor general condition, which does not allow the general anesthesia. Historically, the technique was first applied for the herniated nucleus pulposus. Then, foraminoplasty, which is the enlargement surgery of the narrow foramen, became possible thanks to the development of the high speed drill. It was called the percutaneous endoscopic lumbar foraminoplasty (PELF). More recently, this technique was applied to decompress the lateral recess stenosis, and the technique was named percutaneous endoscopic ventral facetectomy (PEVF). In this review article, we explain in detail the development of the surgical technique of with time with showing our typical cases.

Study of lesions of the lumbar endplate based on the stage of maturation of the lumbar vertebral body: the relationship between skeletal maturity and chronological age.

The lesion of the lumbar endplate is sometimes identified in the vertebrae of children and adolescents. The purpose of this study is to compare between skeletal maturity and chronological age. The second purpose of this study is to clarify the lesions of the lumbar endplate based on the maturation of the lumbar vertebral body. Six hundred and thirty-two (485 men and 147 women) consecutive patients were included. The mean age at the first medical examination was 13.8 years. Their skeletal maturity was evaluated based on the appearances of the secondary ossification center of L3. The area of the endplate lesions was classified into five types. The apophyseal stage was observed from 10 years old to 18 years old, and the apophyseal stage was shown the peak at 14 years old. The appearance of the apophyseal ring was observed earlier in female patients than in male patients. For the concave type, the lesion at upper level vertebra was more prevalent. The anterior and middle type of the lesion at upper level vertebra was more prevalent. For the posterior type, the lesion of the inferior rim of L4 and the lesion of the rim of L5 were more prevalent. This study emerged after comparing skeletal maturity based on the maturation of the lumbar vertebral body with the chronological age of a large number of patients and examining the lesions of the lumbar endplate based on the stage of maturation of the lumbar vertebral body.

Utility of STIR-MRI in Detecting the Pain Generator in Asymmetric Bilateral Pars Fracture: A Report of 5 Cases.

Lumbar spondylolysis usually occurs as a stress fracture in the pars interarticularis of the vertebra. It is a prevalent sports-related disorder and a common cause of low back pain. We encountered five athletes (4 males, 1 female) with severe low back pain. Mean age was 14.5 years. All five patients were found to have bilateral pars fracture. In all cases, staging based on the findings from computed tomography scan of the right and left pars fracture was different. On short tau inversion recovery magnetic resonance imaging (STIR-MRI) of the comparatively newer more recently injured side, high signal intensity changes were obvious and dominant at the intra- and extraosseous area, which would indicate tissue edema and/or bleeding. Furthermore, the imaging findings corresponded to the side of the low back pain. In conclusion, STIR-MRI can effectively distinguish between painful pars fracture and painless pars fracture.

Natural Correction and Adaptation of a Severely Deformed Sacral Dome in an Adolescent with Isthmic Spondylolisthesis: A Case Report.

CASE: A spinal deformity with wedging of L5 and rounding of the surface of the sacral dome is very common in pediatric patients with spondylolisthesis at the L5 vertebral level, and it has been well documented that severe spondylolisthesis is a good indication for spinal arthrodesis. We report the natural correction and adaptation of a severely deformed sacral dome with slippage (40.8%) in a pediatric patient with nonoperative treatment. CONCLUSION: Vertebral deformity in children can be reversible. Orthopaedic surgeons should be aware that pediatric patients with a severe deformity of the sacral dome and vertebral slippage can be managed nonoperatively.

Percutaneous full endoscopic lumbar foraminoplasty for adjacent level foraminal stenosis following vertebral intersegmental fusion in an awake and aware patient under local anesthesia: A case report.

Percutaneous endoscopic surgery for the lumbar spine has become established in the last decade. It requires only an 8 mm skin incision, causes minimal damage to the paravertebral muscles, and can be performed under local anesthesia. With the advent of improved equipment, in particular the high-speed surgical drill, the indications for percutaneous endoscopic surgery have expanded to include lumbar spinal canal stenosis. Transforaminal percutaneous endoscopic discectomy has been used to treat intervertebral stenosis. However, it has been reported that adjacent level disc degeneration and foraminal stenosis can occur following intervertebral segmental fusion. When this adjacent level pathology becomes symptomatic, additional fusion surgery is often needed. We performed minimally invasive percutaneous full endoscopic lumbar foraminoplasty in an awake and aware 50-year-old woman under local anesthesia. The procedure was successful with no complications. Her radiculopathy, including muscle weakness and leg pain due to impingement of the exiting nerve, improved after the surgery. J. Med. Invest. 64: 291-295, August, 2017.

Accurate diagnosis of chronic low back pain in a high-level college athlete: a case report.

A 21-year-old woman who was high-level college softball player presented with a 6-month history of low back pain that had been treated unsuccessfully by medication at local clinics. There was tenderness in the left paravertebral muscle at the lower lumbar level. X-ray and computed tomography revealed congenital scoliosis and an L6 hemivertebra. Short tau inversion recovery magnetic resonance imaging showed a fluid collection at the left L6-S1 facet joint. We performed a diagnostic facet injection, consisting of 1% lidocaine and steroids, that was infiltrated into the left facet joint at L6-S1. Her persistent low back pain disappeared immediately after the facet block. We diagnosed left-sided facet arthritis at L6-S1. Due to her multiple congenital anomalies, excessive loading occurred at the facet joint. Therefore, we opted for conservative management, including mobilization of the thoracic spine and stretching of hamstrings and quadriceps. This case report underscores the importance of accurate diagnosis of low back pain and of the diagnostic utility of short tau inversion recovery magnetic resonance imaging and lumbar facet block in young athletes with chronic spinal pain. J. Med. Invest. 64: 313-316, August, 2017.

Surgical Removal of Circumferentially Leaked Polymethyl Methacrylate in the Epidural Space of the Thoracic Spine after Percutaneous Vertebroplasty.

Background The major complication of percutaneous vertebroplasty (PVP) using polymethyl methacrylate (PMMA) is epidural leakage of PMMA that damages the spinal cord. Methods This is a case report. Result A 77-year-old man presented to our institution with a 6-month history of muscle weakness and an intolerable burning sensation of both lower limbs after PVP with PMMA for thoracic compression fracture at T7 at another hospital. His past medical history was significant for hypertension. He had no history of smoking and alcohol. Computed tomography revealed massive leakage of PMMA into the T6 and T7 spinal canal circumferentially surrounding the spinal cord that caused marked encroachment of the thecal sac. Magnetic resonance images revealed cord compression and intramedullary signal change from T6 to T7 level. After we verified that the leaked PMMA could be easily detached from the dura mater in the cadaveric lumbar spine, surgical decompression and removal of epidural PMMA was performed. The leaked PMMA was carefully thinned down with a high-speed diamond burr. Eight pieces of PMMA were detached from the dura mater easily without causing a dural tear. No neurologic deterioration was observed in the postoperative period. The burning sensation resolved, but the muscle weakness remained unchanged. One and a half years postoperatively, the muscle weakness has improved to ⅘ on the manual muscle strength test, but he could not walk without an aid because of spasticity. Conclusion This report demonstrates the catastrophic epidural extrusion of PMMA following PVP. Extravasated PMMA can be removed through a working space created by means of laminectomy and subtraction of the affected pedicle. Spine surgeons should recognize the possible neurologic complications of PVP and be prepared to treat them using suitable approaches.

Anatomical considerations of the iliac crest on percutaneous endoscopic discectomy using a transforaminal approach.

BACKGROUND CONTEXT: Percutaneous endoscopic discectomy is a minimally invasive procedure for the surgical treatment of lumbar disc herniation (LDH). It can be performed under local anesthesia and requires a skin incision of only 8 mm, with minimal disruption of the spinal structures including ligaments and muscles. However, performing percutaneous endoscopic discectomy with a transforaminal approach (TF-PED) for the lower lumbar spine is associated with some anatomical problems, such as interference from the iliac crest. This study sought to assess the operability of TF-PED for the lower lumbar spine. PURPOSE: The purpose of this study was to assess a three-dimensional relationship between the trajectory of TF-PED and the iliac crest, and the operability of TF-PED at the lower lumbar disc levels (L4-L5 and L5-S1) using CT images. STUDY DESIGN: This is a retrospective study using 323 multiplanar abdominal computed tomography (CT) scans. PATIENT SAMPLE: We retrospectively reviewed contrast-enhanced multiplanar abdominal CT scans of 323 consecutive patients (203 male and 120 female) in our hospital from April 2009 to March 2013. The mean age was 66.5 (range 15-89) years old. OUTCOME MEASURES: The operability of the TF-PED was the outcome measure. MATERIALS AND METHODS: We defined the tangent line in the iliac crest and the superior articular process of the caudal spine as the trajectory line of TF-PED, and evaluated the maximum inclination angle of the trajectory of the TF-PED (α angle) at the L4-L5 and the L5-S1 disc levels. Assuming the use of an oblique viewing endoscope at 25°, we defined α angle≥65° as the operability of TF-PED. RESULTS: (1) Relationship between iliac crest and disc level: The trajectory of the TF-PED interfered with the iliac crest at L4-L5 in 40.2% (right) and 54.5% (left) of the subjects, and at L5-S1 in 99.7% and 100% of the subjects. (2) The maximum inclination angle of the trajectory of TF-PED: the α angles were 84.3° and 82.3° at the L4-L5, and 56.8° and 55.2° at L5-S1. (3) Laterality of the α angle: At both disc levels, the mean age of the subjects with a laterality of ≥10° was significantly higher than that of subjects with a laterality of <10°. (4) Operability of TF-PED: At L4-L5, TF-PED could be performed in 94.4% and 90.4% of the subjects. In contrast, at L5-S1 the procedure could be performed in 24.1% and 19.2% of the subjects (male: 15.8% and 10.8%, female: 38.3% and 33.3%). CONCLUSIONS: From the results of this study, the trajectory of TF-PED can be limited by the surrounding anatomical structures. The maximum inclination angle indicated that treatment for the central type of LDH at the L5-S1 disc level was considered more difficult than that at the L4-L5 disc level because of the iliac crest. In the clinical setting, such anatomical particularities can be overcome by using a more perpendicular approach (hand-down technique) with the possible addition of a foraminoplasty. Moreover, we found that we must consider the laterality of the trajectory of TF-PED in terms of the patients' age or sex.

A new concept of transforaminal ventral facetectomy including simultaneous decompression of foraminal and lateral recess stenosis: Technical considerations in a fresh cadaver model and a literature review.

Percutaneous endoscopic surgery for the lumbar spine, which was established in the last decade, requires only an 8-mm skin incision and causes minimal damage to the paravertebral muscles; thus, it is considered to be a minimally invasive technique for spinal surgery. It has been used to perform percutaneous endoscopic discectomy via two main approaches: the TF approach is a posterolateral one through the intervertebral foramen and can be done under local anesthesia; the IL approach is a more traditional one through the interlaminar space and is difficult to perform under local anesthesia. Recently, these techniques have been applied for lumbar spinal stenosis (LSS), the TF method for foraminal stenosis under local anesthesia, and the IL method for central and lateral recess stenosis under general anesthesia. In this study, using a fresh human cadaver model, we performed simultaneous decompression of the lateral recess and foraminal stenosis at L4-5 using the TF approach. Computed tomography confirmed enlargement of the lateral recess and intervertebral foramen. This technique, which can be performed under local anesthesia, should benefit elderly patients with LSS and poor general condition due to multiple comorbidities. Finally, we introduce the concept of percutaneous transforaminal ventral facetectomy using a spinal percutaneous endoscope. J. Med. Invest. 64: 1-6, February, 2017.

The reduction and direct repair of isthmic spondylolisthesis using the smiley face rod method in adolescent athlete: Technical note.

Presently, lumbar spondylolisthesis did not have the indication of direct repair surgery because of the difficulty to reduce the slippage. In this report, we presented a case and described a minimally invasive direct repair surgery to reduce and repair the pars interarticularis defects of lumbar spondylolisthesis. First, curettage and removal of the synovium of the pars interarticularis and decompression of nerve root are conducted. Next, cancellous bone is harvested from the iliac crest. And then the Percutaneous Pedicle Screws are inserted bilaterally. A rod is bended and placed just caudal to the spinous process. We can make reposition of slipped vertebra and stabilize the loose lamina more firmly using a reduction tool and a rod pusher. Finally, bone grafts are implanted onto the pars defects. The Smiley face rod method is very useful to reduce the slippage and repair the pars defects in the lumbar spondylolisthesis especially in adolescent athletes. J. Med. Invest. 64: 168-172, February, 2017.