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.

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.

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

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

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.

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

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

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

PURPOSES: To evaluate the usefulness of our original five questions in a medical interview for diagnosing discogenic low back pain (LBP), and to establish a support tool for diagnosing discogenic LBP. MATERIALS AND METHODS: The degenerative disc disease (DDD) group (n = 42) comprised patients diagnosed with discogenic LBP associated with DDD, on the basis of magnetic resonance imaging findings and response to analgesic discography (discoblock). The control group (n = 30) comprised patients with LBP due to a reason other than DDD. We selected patients from those who had been diagnosed with lumbar spinal stenosis and had undergone decompression surgery without fusion. Of them, those whose postoperative LBP was significantly decreased were included in the control group. We asked patients in both groups whether they experienced LBP after sitting too long, while standing after sitting too long, squirming in a chair after sitting too long, while washing one's face, and in the standing position with flexion. We analyzed the usefulness of our five questions for diagnosing discogenic LBP, and performed receiver operating characteristic (ROC) curve analysis to develop a diagnostic support tool. RESULTS: There were no significant differences in baseline characteristics, except age, between the groups. There were significant differences between the groups for all five questions. In the age-adjusted analyses, the odds ratios of LBP after sitting too long, while standing after sitting too long, squirming in a chair after sitting too long, while washing one's face, and in standing position with flexion were 10.5, 8.5, 4.0, 10.8, and 11.8, respectively. The integer scores were 11, 9, 4, 11, and 12, respectively, and the sum of the points of the five scores ranged from 0 to 47. Results of the ROC analysis were as follows: cut-off value, 31 points; area under the curve, 0.92302; sensitivity, 100%; and specificity, 71.4%. CONCLUSIONS: All five questions were useful for diagnosing discogenic LBP. We established the scoring system as a support tool for diagnosing discogenic LBP.

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

BACKGROUND: Percutaneous endoscopic lumbar discectomy (PELD) is one of the less invasive treatments of lumbar disc herniation (LDH), and has three different operative approaches. This study focused on the interlaminar approach (ILA) and investigated the appropriate operative route for this approach. METHODS: ILA was performed in 41 patients with LDH. The width of the interlaminar space, LDH size, and positional relation between LDH and the corresponding nerve root were radiologically evaluated. Thirty-three LDHs were removed via the shoulder of the corresponding nerve root and eight were removed via the axilla of the corresponding nerve root and dural sac. Pre- and postoperative status were evaluated using the modified Japanese Orthopedic Association (mJOA) and numerical rating scale (NRS) scores. RESULTS: The mean age was 41.5 years; there was single-level involvement, mostly at L5/S1 (33 cases). The mean recovery rate of mJOA score was 59.8% and mean pre- and postoperative NRS scores were 5.8 and 0.98, respectively. Relatively severe complications developed in three patients treated by ILA via the shoulder. There was persistent numbness in the corresponding nerve area, transient muscular weakness, and transient bladder and rectal disturbance, may be due to excessive compression of the nerve root and/or dural sac by the endoscopic sheath. CONCLUSIONS: ILA can be used to treat LDH revealing an interlaminar space of ≥20 mm. The procedure is minimally invasive and effective; however, appropriate selection of an operative route is important to avoid operative complications. Particularly for large LDH, the operative route via the axilla should be considered.

Modified Open-Door Laminoplasty Using a Ceramic Spacer and Suture Fixation for Cervical Myelopathy.

PURPOSE: To introduce a new simple technique using suture anchors and ceramic spacers to stabilize the elevated laminae in open-door cervical laminoplasty. Although ceramic spacers were placed in the opened laminae and fixed with nylon threads in this series, it was occasionally difficult to fix the nylon threads to the lateral mass. MATERIALS AND METHODS: Study 1: A preliminary study was conducted using a suture anchor system. Sixteen consecutive patients who underwent surgery for cervical myelopathy were prospectively examined. Study 2: The second study was performed prospectively to evaluate the feasibility of this new technique based on the result of the preliminary study. Clinical outcomes were examined in 45 consecutive patients [cervical spondylotic myelopathy (CSM)] and 43 consecutive patients (OPLL). The Japanese Orthopedic Association scoring system (JOA score), axial neck pain, and radiological findings were analyzed. RESULTS: 1) In one case, re-operation was necessary due to dislodgement of the ceramic spacer following rupture of the thread. 2) In all patients, postoperative CT scans showed that the anchors were securely inserted into the bone. In the CSM group, the average JOA score improved from 9.5 points preoperatively to 13.3 at follow-up (recovery 51%). In the OPLL group, the average JOA score improved from 10.1 (5-14) points preoperatively to 14.4 (11-16) at follow-up (recovery 62%). There were no serious complications. CONCLUSION: The use of the suture anchor system made it unnecessary to create a hole in the lateral mass and enabled reliable and faster fixation of the HA spacers in open-door laminoplasty.

Short-segment fixation without fusion for thoracolumbar burst fractures with neurological deficit can preserve thoracolumbar motion without resulting in post-traumatic disc degeneration: a 10-year follow-up study.

STUDY DESIGN: Prospective consecutive series. OBJECTIVE: To evaluate the post-traumatic disc degeneration and range of motion 10 years after short-segment fixation without fusion for thoracolumbar burst fractures with neurological deficit. SUMMARY OF BACKGROUND DATA: Early clinical results of short-segment fixation without fusion for thoracolumbar burst fractures were satisfactory. However, the long-term results have not been reported, and post-traumatic disc degeneration and preservation of thoracolumbar motion have not been elucidated. METHODS: Twelve patients who had thoracolumbar burst fractures and associated incomplete neurological deficit, operatively treated within 4 days of admission and had their implants removed within 1 year, were prospectively followed for at least 10 years. Following indirect reduction and pedicle screw fixation, transpedicular intracorporeal hydroxyapatite grafting to the fractured vertebrae was performed. RESULTS: Sagittal alignment was improved from a mean preoperative kyphosis of 17° to -2° (lordosis) by operation, but was found to have slightly deteriorated to 2° at the final follow-up observation. With respect to back pain, 8 patients did not report back pain. Three reported occasional minimal pain, and 1 reported moderate pain. None reported severe pain or needed daily dosages of analgesics.Regarding disc degeneration, the shape of the disc adjacent to the fractured vertebra had not changed from the preoperative to the 10-year postoperative magnetic resonance image (MRI). Although signal intensity of the disc had decreased by 1 grade from the preoperative to the 2-year postoperative MRI, the intensity had not changed from the 2-year postoperative MRI to the 10-year postoperative MRI. At the 10-year follow-up, flexion-extension radiographs revealed that a mean range of motion at the disc adjacent to the fractured vertebra was 12º (range; 5-19). CONCLUSION: This unprecedented 10-year follow-up study demonstrated that posterior indirect reduction, transpedicular hydroxyapatite grafting, and pedicle screw fixation does not require fusion to a segment, thereby preserves thoracolumbar motion without resulting in post-traumatic disc degeneration. LEVEL OF EVIDENCE: 4.

Asymmetrical pedicle subtraction osteotomy for rigid degenerative lumbar kyphoscoliosis.

STUDY DESIGN: A prospectively study. OBJECTIVE: Our objective was to clarify the safety and efficacy of asymmetrical pedicle subtraction osteotomy (PSO) in the treatment of severe adult lumbar deformities prospectively. SUMMARY OF BACKGROUND DATA: Vertebral wedge osteotomy provides good correction of kyphosis but has rarely been applied to degenerative lumbar kyphoscoliosis. METHODS: A total of 14 patients who had undergone corrective osteotomy were enrolled. The average age at PSO was 67 years (range, 45-76 yr). The minimum follow-up was 2 years. Patient questionnaires were administered prospectively. Radiographical parameters including sagittal and coronal balance were analyzed. RESULTS: Average operative time was 310 minutes (range, 254-375 min). Average blood loss was 1090 mL (range, 700-2900 mL).Mean preoperative lumbar lordosis improved from -3° to 42° at the final follow-up, and sagittal balance improved from 12 to 3 cm, respectively. Mean lumbar scoliosis improved from 40° to 12°, and coronal offset improved from 3 to 1 cm, respectively. There was also statistically significant improvement from preoperative to final evaluation in all clinical domains. There were 4 complications: 1 dural tear, 2 hook dislodgements at the cephalad side requiring revision instrumentation, and 1 rod breakage not requiring surgical intervention. Overall, all 14 patients were satisfied with their surgical management and would choose to repeat the procedure. CONCLUSION: Our data suggest that the surgical procedure of asymmetrical PSO is to correct the scoliosis, to restore the lumbar lordosis by way of convex-sided posterolateral wedge osteotomy, and may go a long way toward solving the problems of rigid lumbar degenerative kyphoscoliosis.

Subsequent vertebral fractures following spinal fusion surgery for degenerative lumbar disease: a mean ten-year follow-up.

STUDY DESIGN: Case-control study. OBJECTIVE: To assess the long-term prevalence of vertebral fractures after lumbar spinal fusion with instrumentation. SUMMARY OF BACKGROUND DATA: The incidence of the adjacent and the nonadjacent, remote level subsequent vertebral fractures after lumbar spinal fusion is not well described in the literature. METHODS: The study is a retrospective analysis of 100 consecutive patients of 55 years of age or older with spinal fusion for degenerative diseases between L1 and S1, and instrumentation for less than 4 segments. Patients with prevalent vertebral fractures defined at the time of surgery, or patients with secondary causes of osteoporosis were excluded. Mean follow-up period was 10.2 years (range, 7-14 years). Acute vertebral fractures were determined by magnetic resonance imaging and lateral spine radiographs. RESULTS: Acute vertebral fractures were determined in 20 vertebrae in 14 (24%) of the 59 female patients, whereas 1 male patient (2%) had 1 vertebral fracture during the follow-up period. Eighteen of the 21 fractures occurred within 2 years of the spinal instrumentation surgery. Regarding time to fracture occurrence after surgery, adjacent level fractures occurred within 8 months, and remote level fractures occurred between 8 and 22 months after surgery. CONCLUSION: Postmenopausal female patients who underwent lumbar spinal instrumentation surgery were susceptible to develop subsequent vertebral fractures within 2 years after surgery. The greater the number of spinal segments between the fracture and the instrumentation was, the longer the time after surgery.

Transpedicular hydroxyapatite grafting with indirect reduction for thoracolumbar burst fractures with neurological deficit: A prospective study.

BACKGROUND: The major problem after posterior correction and instrumentation in the treatment of thoracolumbar burst fractures is failure to support the anterior spinal column leading to loss of correction of kyphosis and hardware breakage. We conducted a prospective consecutive series to evaluate the outcome of the management of acute thoracolumbar burst fractures by transpedicular hydroxyapatite (HA) grafting following indirect reduction and pedicle screw fixation. MATERIALS AND METHODS: Eighteen consecutive patients who had thoracolumbar burst fractures and associated incomplete neurological deficit were operatively treated within four days of admission. Following indirect reduction and pedicle screw fixation, transpedicular intracorporeal HA grafting to the fractured vertebrae was performed. Mean operative time was 125 min and mean blood loss was 150 ml. Their implants were removed within one year and were prospectively followed for at least two years. RESULTS: The neurological function of all 18 patients improved by at least one ASIA grade, with nine (50%) patients demonstrating complete neurological recovery. Sagittal alignment was improved from a mean preoperative kyphosis of 17°to -2°(lordosis) by operation, but was found to have slightly deteriorated to 1° at final followup observation. The CT images demonstrated a mean spinal canal narrowing preoperatively, immediate postoperative and at final followup of 60%, 22% and 11%, respectively. There were no instances of hardware failure. No patient reported severe pain or needed daily dosages of analgesics at the final followup. The two-year postoperative MRI demonstrated an increase of one grade in disc degeneration (n = 17) at the disc above and in 11 patients below the fractured vertebra. At the final followup, flexion-extension radiographs revealed that a median range of motion was 4, 6 and 34 degrees at the cranial segment of the fractured vertebra, caudal segment and L1-S1, respectively. Bone formation by osteoconduction in HA granules was unclear, but final radiographs showed healed fractures. CONCLUSIONS: Posterior indirect reduction, transpedicular HA grafting and pedicle screw fixation could prevent the development of kyphosis and should lead to reliable neurological improvement in patients with incomplete neurological deficit. This technique does not require fusion to a segment, thereby preserves thoracolumbar motion.

Changes in vertebral wedging rate between supine and standing position and its association with back pain: a prospective study in patients with osteoporotic vertebral compression fractures.

STUDY DESIGN: Prospective consecutive series. OBJECTIVE: To analyze supine and standing radiographs and the association of back pain using subjective pain criteria. SUMMARY OF BACKGROUND DATA: It has been considered that there is little correlation between the degree of collapse of the vertebral body and the level of pain. In previous studies, however, measurements have only been based on supine radiographs. Although there were 2 authors who reported the results of supine lateral and standing lateral radiographs in patients with thoracolumbar vertebral fractures, as far as we know, there has not been any detailed report concerning the correlation between radiologic findings using supine and standing lateral radiographs and back pain. METHODS: We examined 100 consecutively treated patients, prospectively. Back pain and the supine and standing radiographs were assessed 1 month after injury. Changes in vertebral wedging rate (WR) from supine to standing position (Delta WR) was reported by the following equation: Delta WR = WR(standing)-WR(supine). RESULTS: The median age of the cohort was 75 years (range, 60-89 years). The median VAS of back pain at supine position, at standing position, and when standing erect was 13, 33, and 41, respectively. The median wedging rate on the supine and standing radiographs were 28% and 37%, respectively (P < 0.001). There was a significant correlation between Delta WR and back pain when standing erect (r = 0.79, P < 0.001). CONCLUSION: Changes in vertebral wedging rate between supine and standing position and its association with back pain may give a clue to the pathogenesis of pain from osteoporotic thoracolumbar vertebral compression fractures.