Mitsunobu Abe

Foraminoplastic transforaminal percutaneous endoscopic discectomy at the lumbosacral junction under local anesthesia in an elite rugby player

Percutaneous endoscopic discectomy (PED) is the least invasive disc surgery available at present. The procedure can be performed under local anesthesia and requires only an 8 mm skin incision. Furthermore, damage to the back muscle is considered minimal, which is particularly important for disc surgery in athletes. However, employing the transforaminal (TF) PED approach at the lumbosacral junction can be challenging due to anatomical constraints imposed by the iliac crest. In such cases, foraminoplasty is required in addition to the standard TF procedure. A 28-year-old man who was a very active rugby player visited us complaining of lower back and left leg pain. His visual analog scale (VAS) score for pain was 8/10 and 3/10, respectively. MRI revealed a herniated nucleus pulposus at L5-S level. TF-PED was planned; however, the anatomy of the iliac crest was later found to prevent access to the herniated mass. Foraminoplasty was therefore performed to enlarge the foramen, thereby allowing a cannula to be passed through the foramen into the canal without causing exiting nerve injury. The herniated mass was then successfully removed via the TF-PED procedure. Pain resolved after surgery, and his VAS score decreased to 0/10 for both back and leg pain. The patient returned to full rugby activity 8 weeks after surgery. In conclusion, even with an intracanalicular herniated mass at the lumbosacral junction, a TF-PED procedure is possible if additional foraminoplasty is adequately performed to enlarge the foramen.

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

State-of-the-art ultrasonographic findings in lower extremity sports injuries

Athletes sometimes experience overuse injuries. To diagnose these injuries, ultrasonography is often more useful than plain radiography, computed tomography (CT), or magnetic resonance imaging (MRI). Ultrasonography can show both bone and soft tissue from various angles as needed, providing great detail in many cases. In conditions such as osteochondrosis or enthesopathies such as Osgood-Schlatter disease, Sinding-Larsen-Johansson disease, bipartite patella, osteochondritis dissecans of the knee, painful accessory navicular,and jumpers knee, ultrasonography can reveal certain types of bony irregularities or neovascularization of the surrounding tissue. In patients of enthesopathy, ultrasonography can show the degenerative changes at the insertion of the tendon. Given its usefulness in treatment, ultrasonography is expected to become essential in the management of overuse injuries affecting the lower limb in athletes. J. Med. Invest. 62: 109-113, August, 2015.

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

Percutaneous Endoscopic Lumbar Discectomy for a Huge Herniated Disc Causing Acute Cauda Equina Syndrome: A Case Report

Microsurgery for lumbar disc herniation that requires surgical intervention has been well described. The methods vary from traditional open discectomy to minimally invasive techniques. All need adequate preanesthetic preparation of patients as general anesthesia is required for the procedure, and nerve monitoring is necessary to prevent iatrogenic nerve injury. Conventional surgical techniques sometimes require the removal of the corresponding lamina to assess the nerve root and herniated disc, and this may increase the risk for posterior instability of the vertebral body. Should this occur, fusion surgery may be needed, further increasing morbidity and cost. We present here a case of lumbar herniated disc fragments causing acute cauda equina syndrome that were endoscopically resected through a transforaminal approach in an awake patient under local anesthesia. Percutaneous endoscopic discectomy under local anesthesia proved to be a better alternative to open back surgery as it made immediate intervention possible, was associated with fewer perioperative complications and morbidity, minimized soft tissue damage, and allowed early rehabilitation with a better outcome and greater patient satisfaction. In addition to these advantages, percutaneous endoscopic discectomy protects other approaches that may be needed in subsequent surgeries, whether open or minimally invasive.

State of the art: Intraoperative neuromonitoring in spinal deformity surgery

Application of deformity correction spinal surgery has increased substantially over the past three decades in parallel with improvements in surgical techniques. Intraoperative neuromonitoring (IOM) techniques,including somatosensory evoked potentials (SEPs), muscle evoked potentials (MEPs), and spontaneous electromyography (free-run EMG), have also improved surgical outcome by reducing the risk of iatrogenic neural injury. In this article, we review IOM techniques and their applications in spinal deformity surgery. We also summarize results of selected studies including hundreds of spinal correction surgeries. These studies indicate that multimodal IOM of both motor and sensory responses is superior to either modality alone for reducing the incidence of neural injury during surgery. J. Med. Invest. 62: 103-108, August, 2015.

Rehydration of a degenerated disc on MRI synchronized with transition of Modic changes following stand-alone XLIF

Lumbar intervertebral disc degeneration (LDD) is known to be associated with low back pain (LBP) and leads to degenerative lumbar disease. LDD is considered to be irreversible, and no truly effective treatment that suppresses LDD or regenerates the degenerated disc has been established thus far. Here, we report the case of a 42-year-old woman with a 10-year history of persistent LBP. Magnetic resonance imaging (MRI) demonstrated degenerative changes (Pfirrmann classification: grade IV) in the L4–5 intervertebral disc with type I and III mixed Modic changes adjacent to the disc. Conservative treatments were not effective, so we opted for stand-alone extreme lateral interbody fusion (XLIF). One year after the operation, the LBP had almost disappeared. Follow-up MRI revealed transition of the Modic changes from type I to type III. In addition, rehydration of the degenerated disc behind the XLIF cage was evident (Pfirrmann classification changed from grade IV to grade II). To our knowledge, this is the first report of a change in LDD. Several factors are likely responsible for the regenerative response, including curettage of the hyaline cartilaginous endplates and auto-iliac cancellous bone grafting, which were considered to have affected nucleus pulposus cells in the residual disc.

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