Kazuta Yamashita

Risk Assessment of Lumbar Segmental Artery Injury During Lateral Transpsoas Approach in the Patients With Lumbar Scoliosis.

Study Design. A retrospective study using 27 contrast-enhanced multi-planar computed tomography scans of subjects with lumbar scoliosis. Objective. To assess the risk of injury of lumbar segmental arteries during transpsoas approach in patients with lumbar scoliosis. Summary of Background Data. Although lumbar interbody fusion using big intervertebral cage through transpsoas approach has a big advantage to correct coronal and sagittal deformity in patients with spinal deformity, the risk for injury of lumbar segmental artery is always concerned. Methods. The abdominal-contrast enhanced multi-planar computed tomography scans of 27 subjects with lumbar scoliosis with over 15° of Cobb angle were retrospectively reviewed. The coronal views through the posterior one third of the intervertebral discs were reviewed. The cranio-caudal intervals of the adjacent segmental arteries at each intervertebral level were measured. The recommended working space for the lateral transpsoas approach using extreme lateral interbody fusion retractor is 24 mm in the cranio-caudal direction. The cutoff value for an intersegmental Cobb angle that would estimate a cranio-caudal interval of less than 24 mm was determined using a receiver operating characteristic curve. Results. The average interval between the cranio-caudal lumbar segmental arteries on the concave side was significantly shorter than that on the convex side (29.9 vs. 33.6 mm, P < 0.05). The differences in the intervals between the convex and concave sides were correlated with the corresponding intersegmental Cobb angle (r = 0.65, P < 0.05). Receiver operating characteristic curve analysis revealed that cutoff value for the best prediction of an interval less than 24 mm was 14.5°, with a specificity of 94.3% and sensitivity of 71.4%. Conclusion. This study demonstrated that female patients with lumbar scoliosis with an intersegmental Cobb angle higher than 14.5° would be at high risk for potential injury to the lumbar artery during a transpsoas approach for extreme lateral interbody fusion from the concave side. Level of Evidence: 4

Conservative Treatment for Bony Healing in Pediatric Lumbar Spondylolysis

Study Design. A retrospective review of prospectively collected data. Objective. The aim of this study was to investigate recent outcomes of conservative treatment for bony healing in pediatric patients with lumbar spondylolysis (LS) and to identify the problems that need to be resolved. Summary of Background Data. Several diagnostic and therapeutic techniques for LS have been developed recently, leading to better outcomes for bony healing. Methods. Overall, 63 consecutive pediatric patients (53 boys and 10 girls) with LS (average age: 13.8 years; range: 6–17 years) were analyzed. Diagnosis and staging (very early, early, progressive, and terminal) were based on multidetector computed tomography (CT) scans and magnetic resonance imaging (MRI). For all patients except those with terminal-stage pars defect, conservative treatment included rest, avoidance of sports, and the use of a thoraco-lumbo-sacral-type trunk brace. Follow-up MRI was performed monthly. When the signal changes resolved, CT scans were obtained to assess bony healing. Results. Three patients dropped out during the study period. A total of 60 patients were included (50 boys and 10 girls) in this study (follow-up rate: 95.2%), with 86 instances of LS (very early: 36, early: 16, progressive: 15, terminal: 19) in 65 laminae. In the very early stage, the bony healing rate was 100%, and average treatment period was 2.5 months (range: 1–7 months). In the early stage, the bony healing rate was 93.8%, and the average treatment period was 2.6 months (range: 1–6 months). In the progressive stage, the bony healing rate was 80.0%, and the average treatment period was 3.6 months (range: 3–5 months). The average overall recurrence rate was 26.1%. All patients showing recurrence eventually achieved bony healing. Conclusion. High bony healing rates and short treatment periods were observed with conservative treatment in pediatric patients with LS. However, the recurrence rates were relatively high. This issue should be targeted in future studies. Level of Evidence: 2

Clinical Significance of High-intensity Zone for Discogenic Low Back Pain: A Review

High-intensity zone (HIZ) was originally described as a high-intensity signal on T2-weighted magnetic resonance (MR) images, located in the posterior annulus fibrosus, clearly separated from the nucleus pulposus. Among symptomatic patients with low back pain, HIZ is present in 28-59% of cases. In morphologically abnormal discs, high sensitivity and specificity of 81% and 79%, respectively, were reported for HIZs and concordant pain during discography. In contrast, another report indicated low rates. Although most papers reported high sensitivity and specificity for this relationship, it remains controversial. Regarding the pathology of HIZs, inflammatory granulation tissues are found at sites showing HIZs. Such inflammatory tissues produce pro-inflammatory cytokines and mediators, which sensitize the nociceptors within the disc and cause pain. An effective treatment for this condition is yet to be established. Recently, minimally invasive surgery using percutaneous endoscopic discectomy (PED) under local anesthesia was introduced. After removal of the degenerated disc material, the HIZ is identified with the endoscope and then coagulated and modulated with a bipolar radio pulse. This technique is called thermal annuloplasty. In conclusion, HIZs is an important sign of painful intervertebral disc disruption, if identified precisely based on factors such as location and intensity.

Risk Management for Avoidance of Major Vascular Injury due to Lateral Transpsoas Approach.

Study Design. A retrospective study using 323 contrast-enhanced, multi-planner three-dimensional computed (3D-CT) scans. Objective. The aim of this study was to identify risk factors for injury to the major vessels in the lateral transpsoas approach. Summary of Background Data. To avoid critical complications such as major vessel injury, it is essential to examine anatomical information related to preoperative risk management that is specific to the lateral transpsoas approach. Methods. The abdominal contrast-enhanced, multi-planner 3D-CT scans of 323 consecutive subjects (203 males and 120 females, 15–89 years old) were retrospectively reviewed. The true axial views were used for evaluation of the locations of the major vein and artery at L3 to L4 and L4 to L5. According to the Moro system, the axial view was divided into 6 zones from the front side (A, I II, III, IV, P) and the locations of the dorsal tangential line of the major vessels were evaluated. Results. At the L3 to L4 level, the dorsal tangential line of the major vein located in zone A was found in 18% of subjects, in zone I in 74%, and in zone II in 8%. The line of the major artery was located in zone A in 92.6% of subjects and in zone I in 7.1%. At the L4 to L5 level, the line of the major vein was located in zone A in 5% of subjects, in zone I in 75%, in zone II in 20%, and in zone III in only 1 subject. The line of the major artery was identified in zone A in 87% of subjects, in zone I in 12%, and in zone II in 1%. Women had significant dorsal-migrated veins and arteries at both spinal levels (P < 0.01). Conclusion. To avoid critical complications in extreme lateral lumbar interbody fusion, careful preoperative radiological evaluation of the major vessels and intraoperative care are important. Level of Evidence: 3

Revision percutaneous endoscopic lumbar discectomy under the local anesthesia for the recurrent lumbar herniated nucleus pulposus in a high class athlete: A case Report.

Percutaneous endoscopic discectomy (PED) is a minimally invasive spinal technique and has several advantages compared with open surgery. We describe repeat PED surgery for recurrent herniated nucleus pulposus (HNP). The patient was a 33-year-old handball high level player. Previously, he underwent transforaminal PED under local anesthesia for intracanalicular HNP at L4-5 level about 2 years ago. He could return to his original competitive level. Two years later, he felt low back and right leg pain again when he was playing handball. Magnetic resonance imaging revealed the recurrence of HNP at the same level. We conducted transforaminal PED again using the exact same route as the previous surgery. Although there was a little adhesion around the L5 nerve root, we could easily identify and remove the herniated mass using endoscopic forceps. Immediately after the surgery, the low back and leg pain disappeared. Repeat PED surgery for recurrence of lumbar disc herniation is effective especially for athletes because of the benefits of PED, including surgery under local anesthesia, preservation of normal posterior structures, less postoperative pain, early discharge, and faster return to sports.

Radiation Exposure to the Surgeon and Patient During a Fluoroscopic Procedure: How High is the Exposure Dose? A Cadaveric Study.

Study Design. Using fresh cadavers, real-time dosimeters were used to estimate the radiation exposure dose from C-arm fluoroscopy to surgeons, medical staff, and patients during various procedures. Objective. The aim of this study was to evaluate the radiation exposure dose from C-arm fluoroscopy, which is used to generate real-time images of the human body, under a variety of conditions and in different areas. Summary of Background Data. Awareness of the harmful effects of long-term low-dose radiation is rising. There are no all-inclusive reports evaluating the radiation exposure dose to medical staff associated with fluoroscopic procedures that can accurately simulate the real clinical situation. Methods. Seven fresh cadavers were irradiated for 1, 3, and 5 minutes with C-arm fluoroscopy. The x-ray source was positioned under the table, over the table, and laterally. Radiation exposure doses were measured at different simulated areas such as the center area, and the surgeons hand or thyroid gland. Results. There were significant differences in the radiation exposure dose under different conditions and for different irradiated areas. The risk of direct and scatter radiation exposure was the greatest with the lateral position, which increased by more than 200 times and more than 30 times, respectively, compared with that from a position under the table. Direct radiation was attenuated to less than one-hundredth after passing through the body of the cadaver. All radiation exposure doses were positively correlated with total exposure time. Conclusion. Our study revealed the direct and scatter radiation exposure dose from C-arm fluoroscopy to different areas under a variety of conditions when fluoroscopy is used to generate real-time images of the human body. Our results serve as a guide for medical staff to understand the risk of radiation exposure during each fluoroscopic procedure. Medical staff, especially surgeons, should consider how to protect themselves and reduce radiation exposure by using appropriate shielding. Level of Evidence: 4

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.

Comparison of Functional Outcome Between Early and Delayed Internal Fixation Using Volar Locking Plate for Distal Radius Fractures.

The purpose of this study was to assess the effect of timing (Early (E) group vs Delayed (D) group) of internal fixation for distal radius fractures on forearm and wrist function in patients who underwent the surgery. The subjects were one hundred six patients who had extra-articular fractures of the dorsally displaced distal radius and were treated with a volar locking plate. The subjects were divided into two groups: E group (Operation on the day of injury or the next day, n = 76 ; and the D group (Operation at 7 days after injury or later, n = 30). Follow-up examinations conducted at 4, 12, and 48 weeks after surgery included measurements of wrist and forearm ranges of motion (ROM), measurement of grip strength (GS), Disability of the Arm, Shoulder and Hand score (DASH), and complications, retrospectively. The patients in both groups improved significantly with respect to ROM, GS, and DASH. At 4 weeks, the patients in the E group had better forearm motion, At 4 and 12 weeks, those who had undergone early surgery had significantly better wrist motion, GS and DASH. At 48 weeks, there were no differences between the groups in ROM, GS, or DASH. Patients with dorsally displaced extra-articular fractures of the distal radius can expect to have better short-term outcomes with early treatment, open reduction and internal fixation using a volar locking plates.

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.

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.