Oblique lateral interbody fusion for lumbosacral fractional curve correction in degenerative lumbar scoliosis.

PURPOSE: In combined anterior-posterior adult spinal deformity surgery, the optimal combination of anterior and posterior procedures remains unclear. We aimed to demonstrate the radiological outcomes and relevant factors in oblique lateral interbody fusion (OLIF) for lumbosacral fractional curve (FC) correction combined with open posterior surgery in degenerative lumbar scoliosis (DLS). METHODS: This study involved 42 consecutive patients with DLS who had a major curve (MC) ≥ 20° and an FC (L4 to S1) ≥ 10°, and underwent a combined anterior-posterior surgery Changes in the MC, FC, coronal balance distance, type of coronal imbalance, coronal/sagittal disc angle at L4-5 and L5-S1, L4 and L5 tilt, and sagittal parameters were examined. The associations between FC correction and demographic, surgical, and radiological factors were analysed. RESULTS: The FC decreased from 16.9 ± 7.3° preoperatively to 6.6 ± 4.4° at the last follow-up (P < 0.001). The coronal disc angle at L4-5 and L5-S1 were, respectively, 6.8 ± 2.2° and 6.0 ± 4.1° preoperatively and decreased to 2.2 ± 2.1 and 1.2 ± 1.3° at the last follow-up (both P < 0.001). The changes in FC were greater in uppermost instrumented level > T10 (P < 0.001), and associated with the preoperative FC (r = 0.820, P < 0.001), L4 tilt (r = 0.434, P = 0.007), and L5 tilt (r = 0.462, P = 0.003). CONCLUSION: OLIF at the FC combined with open posterior surgery is an effective combined anterior-posterior correction strategy in DLS.

Pediatric Spinal Trauma at a Single Level 1 Trauma Center: Review of 62 Cases.

Background: Traumatic spinal injuries in children are uncommon and result in different patterns of injuries due to the anatomical characteristics of children's spines. However, there are only a few epidemiological studies of traumatic spinal injury in children. The purpose of this study was to investigate the characteristics of traumatic spinal injury in children. Methods: We retrospectively reviewed the cases of pediatric patients (age < 18 years) with traumatic spinal injury who were treated at a level 1 trauma center between January 2017 and December 2021. We divided them into three groups according to age and analyzed demographics, injury mechanism, level of injury, and injury pattern. Results: A total of 62 patients (255 fractures) were included, and the mean age was 13.8 ± 3.2 years. There were 5 patients (22 fractures) in group I (0-9 years), 24 patients (82 fractures) in group II (10-14 years), and 33 patients (151 fractures) in group III (15-17 years). Both the Injury Severity Score and the Revised Trauma Score were highest in group I, but there was no statistical difference between the age groups. Fall from height was the most common injury mechanism, of which 63% were suicide attempts. The level of spinal injury was different in each age group, T10-L2 injury being the most common. In all age groups, the number of multilevel continuous injury was larger than that of single-level injury or multilevel noncontinuous injury. Surgical intervention was required in 33.9%, and mortality was 3.2%. Conclusions: In our study, fall from height was the most common mechanism of injury, and there were many suicide attempts associated with mental health issues. Thoracolumbar junction injuries were predominant, and the rate of multilevel contiguous injuries was high. The support and interest of the society and families for adolescent children seem crucial in preventing spinal trauma, and image testing of the entire spine is essential when evaluating pediatric spinal injuries.

Incidence and Risk Factors for Wound Revision after Surgical Treatment of Spinal Metastasis: A National Population-Based Study in South Korea.

Wound complications are commonly seen after surgeries for metastatic spine tumors. While numerous studies have pinpointed various risk factors, there is ongoing debate. Therefore, this study aimed to verify various factors that are still under debate utilizing the comprehensive Korean National Health Insurance Service database. We identified and retrospectively reviewed a cohort of 3001 patients who underwent one of five surgical treatments (corpectomy, decompression and instrumentation, instrumentation only, decompression only, and vertebroplasty) for newly diagnosed spinal metastasis between 2009 and 2017. A Cox regression analysis was performed to determine the risk factors. A total of 197 cases (6.6%) of wound revision were found. Only the surgical method and Charlson comorbidity index were significantly different between the group that underwent wound revision and the group that did not. Regarding surgical methods, the adjusted hazard ratios for decompression only, corpectomy, instrumentation and decompression, and instrumentation only were 1.3, 2.2, 2.2, and 2.4, with these ratios being compared to the vertebroplasty group (p for trend = 0.02). In this regard, based on a sizable South Korean cohort, both surgical methods and medical comorbidity were found to be associated with the wound revision rate among spinal surgery patients for spinal metastasis.

Pregabalin as an effective treatment for acute postoperative pain following spinal surgery without major side effects: protocol for a prospective, randomized controlled, double-blinded trial.

BACKGROUND: Patients experience considerable postoperative pain after spinal surgery. As the spine is located at the centre of the body and supports body weight, severe postoperative pain hinders upper body elevation and gait which can lead to various complications, including pulmonary deterioration and pressure sores. It is important to effectively control postoperative pain to prevent such complications. Gabapentinoids are widely used as preemptive multimodal analgesia, but their effects and side effects are dose-dependent. This study was designed to examine the efficacy and side effects of varying doses of postoperative pregabalin for the treatment of postoperative pain after spinal surgery. METHODS: This is a prospective, randomized controlled, double-blind study. A total of 132 participants will be randomly assigned to the placebo (n = 33) group or to the pregabalin 25 mg (n = 33), 50 mg (n = 33), or 75 mg (n = 33) groups. Each participant will be administered placebo or pregabalin once prior to surgery and every 12 h after surgery for 72 h. The primary outcome will be the visual analogue scale pain score, total dose of administered intravenous patient-controlled analgesia, and frequency of rescue analgesic administered for 72 h from arrival to the general ward after surgery, subdivided into four periods: 1-6 h, 6-24 h, 24-48 h, and 48-72 h. The secondary outcomes will be the incidence and frequency of nausea and vomiting due to intravenous patient-controlled analgesia. Safety will be assessed by monitoring the occurrence of side effects such as sedation, dizziness, headache, visual disturbance, and swelling. DISCUSSION: Pregabalin is already widely used as preemptive analgesia and, unlike nonsteroidal anti-inflammatory drugs, is not associated with a risk of nonunion after spinal surgery. A recent meta-analysis demonstrated the analgesic efficacy and opioid-sparing effect of gabapentinoids with significantly decreased risks of nausea, vomiting, and pruritus. This study will provide evidence for the optimal dosage of pregabalin for the treatment of postoperative pain after spinal surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT05478382. Registered on 26 July 2022.

Cumulative Burden of Being Underweight Increases the Risk of Hip Fracture: A Nationwide Population-Based Cohort Study.

(1) Background: Being underweight is a known risk factor for hip fractures. However, it is unclear whether the cumulative underweight burden affects the incidence of hip fractures. Therefore, we explored the effect of the cumulative underweight burden on the development of hip fractures; (2) Methods: In a cohort of adults aged 40 years and older, 561,779 participants who were not underweight and had no hip fractures from 2007 to 2009 were identified. The risk of hip fracture from the time of the last examination to December 2018 according to the cumulative burden of being underweight (based on 0 to 3 examinations) was prospectively analyzed; (3) Results: During follow-up (mean 8.3 ± 0.8 years), the prevalence of newly diagnosed hip fractures was 0.2%, 0.4%, 0.5%, and 0.9% among those with 0, 1, 2, and 3 cumulative underweight, respectively. The adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of groups meeting the diagnostic criteria for underweight 1, 2, and 3 compared to 0 were 2.3 (1.6−3.3), 2.9 (1.8−4.5), and 4.5 (3.4−6.1), respectively (p for trend < 0.01); (4) Conclusions: The risk of hip fracture increased as the burden of underweight accumulated.

Risk factors for nonunion in oblique lateral interbody fusion.

BACKGROUND: Compared with posterior interbody fusion techniques, oblique lateral interbody fusion (OLIF) offers a larger fusion bed with greater intervertebral space access, use of larger cages, more sufficient discectomy, and better end-plate preparation. However, the fusion rate of OLIF is similar to that of other interbody fusions. This study aimed to examine the factors associated with nonunion in OLIF. METHODS: This study examined 201 disc levels from 124 consecutive patients who underwent OLIF for lumbar degenerative diseases with 1-year regular follow-up. Demographic and surgical factors were reviewed from the medical records. Radiological factors measured were sagittal parameters, intervertebral disc angle (DA) before surgery and at the final follow-up, presence of vertebral end-plate lesions, and cage subsidence. Multivariable logistic regression analysis was performed to identify the factors associated with nonunion. RESULTS: Among the 201 discs, 185 (92.0%) achieved union at 1-year followed up. Smoking, surgery at the L5-S1 level, not performing laminectomy, and a large intervertebral DA were factors associated with nonunion in OLIF (all P < 0.05). Multivariable logistic regression analysis showed two independent variables (surgery at L5-S1 level and not performing laminectomy) as risk factors for nonunion in OLIF. CONCLUSIONS: Not performing laminectomy and surgery at the L5-S1 level were risk factors for nonunion in OLIF. To reduce the nonunion rate, surgeons should consider additional stabilization strategies for the L5-S1 OLIF and perform laminectomy.

A Modified Anterior Column Realignment With Partial Anterior Longitudinal Ligament Release in Oblique Lateral Interbody Fusion.

STUDY DESIGN: Retrospective radiological analysis. OBJECTIVE: To demonstrate the radiological outcome after a modified anterior column realignment (mACR) with partial anterior longitudinal ligament (ALL) release in oblique lateral interbody fusion (OLIF). SUMMARY OF BACKGROUND DATA: Anterior column realignment (ACR) remains a powerful sagittal correction technique in minimally invasive adult spinal deformity surgery and is often combined with posterior column osteotomy (PCO) to achieve more lordosis. OLIF is ideal for ACR because the anterior-to-psoas corridor typically involves the anterolateral half of the disk. METHODS: This study included 112 operated disk levels of 101 consecutive patients who underwent OLIF between L2-L3 and L4-L5 using a 12° lateral cage. The mACR was performed at 73 (65.2%) levels with 30% to 50% sectioning of the ALL. Each operated level was grouped according to the mACR and additional PCO as: (1) no mACR, OLIF only (n=39); (2) mACR with no PCO (n=18); (3) mACR with grade 1 PCO (n=27); (4) mACR with grade 2 PCO (n=22); or (5) mACR with grade 3 PCO (n=6). RESULTS: At the last follow-up, the mean disk lordotic angles were 10.9±2.9°, 12.6±3.0°, 13.3±3.9°, 16.7±3.2°, and 16.8±2.4° in the no mACR, mACR with no PCO, mACR with grade 1 PCO, mACR with grade 2 PCO, and mACR with grade 3 PCO groups, respectively ( P <0.001). The mean increases in disk lordotic angle were 5.8±4.1°, 12.1±6.1°, 13.5±8.7°, 15.8±6.7°, and 17.9±6.2° in each group, respectively ( P <0.001). CONCLUSIONS: ACR can be performed with partial ALL release under direct vision in OLIF without deep dissection into the ventral disk space. The mACR in OLIF is a simple, safe, and effective technique for anterior column lengthening. LEVEL OF EVIDENCE: 4.

Influence of Vascular Anatomy on the Radiologic Outcomes in Oblique Lateral Interbody Fusion at L5-S1.

STUDY DESIGN: This was a retrospective study. OBJECTIVE: The objective of this study was to evaluate whether the anatomy of the left common iliac vein (LCIV) affects the radiologic outcomes in oblique lateral interbody fusion (OLIF) at L5-S1. SUMMARY OF BACKGROUND DATA: Upward mobilization and retraction of the LCIV is an essential technique in OLIF at L5-S1. However, mobilization of the LCIV is sometimes difficult and may affect the surgical outcomes in OLIF at L5-S1. METHODS: This study involved 52 consecutive patients who underwent OLIF at L5-S1 and had >1-year regular follow-up. The configuration of LCIV on preoperative axial magnetic resonance images of the lumbar spine was categorized into 3 types according to the difficulty of mobilization: type I (no requirement for mobilization), type II (potentially easy mobilization), and type III (potentially difficult mobilization). Radiologic parameters included anterior/posterior disk heights (ADH/PDH), disk angle (DA), cage migration, cage subsidence, cage position, and fusion rate at L5-S1. Intraoperative/perioperative events associated with OLIF at L5-S1 were reviewed. Radiologic outcomes among the LCIV types were compared. RESULTS: There were 19 men and 33 women with a mean age of 62.8±9.7 years. The mean follow-up duration was 24.8±15.5 months. The LCIV anatomy was type I in 25 (48.1%) patients, type II in 14 (26.9%), and type III in 13 (25.0%). The mean ADH increased from 7.0±4.7 to 16.9±4.1 mm at the last follow-up (P<0.001), and the mean PDH increased from 2.7±1.7 to 4.9±1.6 mm (P<0.001). The mean DA increased from 5.4±5.4 to 16.9±6.5 degrees (P<0.001). There were no significant differences in ADH, PDH, and DA at the last follow-up among the LCIV types. Two (3.8%) major and 2 (3.8%) minor LCIV injuries were identified, all of which had a type III LCIV. CONCLUSIONS: OLIF at L5-S1 showed favorable radiologic outcomes regardless of the LCIV anatomy. However, type III LCIV patients had a high rate of intraoperative vascular injury.

Rapid Progression to Complete Paraplegia After Electroacupuncture in a Patient With Spinal Dural Arteriovenous Fistula: A Case Report.

Spinal dural arteriovenous fistula (SDAVF) usually has an insidious clinical course, but 5-15% of the cases have acute exacerbations. In some cases, there is an abrupt progression to paraplegia following an epidural injection or anesthesia. Electroacupuncture is a form of acupuncture that applies a small electrical current to needles inserted at specific points in the body. It is widely used for its analgesic effect on back pain. In this study, we report a rare case of SDAVF in which the symptoms of a patient worsened rapidly to complete paraplegia within a few hours after applying electroacupuncture to his back. A 49-year-old man had rapid progression to complete paraplegia within a few hours of electroacupuncture on his back. MRI showed SDAVF and worsening of cord signal change. An emergency operation was performed to ligate the SDAVF. The patient was able to walk 1 month post-operatively. Most of the neurological deficits had disappeared by 1 year post-operatively, with normalization of MRI. Our case emphasizes that SDAVF patients should be careful when exposed to any circumstances that might affect the circulation around the dural arteriovenous fistula, such as electroacupuncture. Patients should also be warned in advance about the possibility of rapid exacerbation of neurological symptoms. Regardless of the severity of the neurological symptoms, immediate treatment is essential for recovery and a better outcome.

Factors affecting disc angle restoration in oblique lateral interbody fusion at L5-S1.

BACKGROUND CONTEXT: Optimal restoration of the L5-S1 disc angle (DA) is an important surgical goal in spinal reconstructive surgery. Anterior approach is beneficial for L5-S1 DA reconstruction and fusion. However, factors associated with a greater DA restoration in oblique lateral interbody fusion (OLIF) at L5-S1 have not been studied. PURPOSE: This study aimed to identify factors that aid in achieving a greater DA in OLIF at L5-S1. STUDY DESIGN/SETTING: A retrospective analysis. PATIENT SAMPLE: This study involved 61 consecutive patients who underwent OLIF at L5-S1 for lumbar degenerative disease and were followed for more than 1 year. Patients with incomplete data or posterior column osteotomy at L5-S1 were excluded. OUTCOME MEASURES: The L5-S1 DA was measured preoperatively, postoperatively, and at the last follow-up on standing lateral lumbar radiographs. The associations between demographics and/or surgical and/or radiological factors and the L5-S1 DA at the last follow-up were analyzed using multiple regression analysis. METHODS: Demographics and surgical factors were reviewed from the medical records with respect to age, sex, body mass index, bone mineral density, diagnosis, surgery level, cage parameters (cage lordotic angle and height), laminectomy performed and/or not performed, estimated blood loss, operative time, configuration of the left common iliac vein. Radiological factors were measured with respect to sagittal parameters, the L5-S1 disc parameters, and the postoperative cage parameters. RESULTS: The mean preoperative DA at L5-S1 was 5.4±5.0°, which increased to 18.9±5.6° postoperatively (p<.001) and was maintained as 16.5±5.9° at the last follow-up (p<.001). The preoperative DA, end plate lesions, anterior spur, facet joint osteoarthritis, or cage position at L5-S1 did not affect the DA at the last follow-up (all p>.05). Multiple regression analysis showed four independent variables, including increased age, increased cage lordotic angle, laminectomy performed, and absence of cage subsidence as the factors associated with the greater DA at L5-S1. CONCLUSIONS: OLIF at L5-S1 showed favorable DA restoration regardless of the preoperative conditions. To achieve a greater DA, surgeons should try to distract the anterior disc space for insertion of a larger lordotic cage. Laminectomy during posterior fixation is recommended for achieving additional DA restoration.

Differentiation of Vertebral Metastases From Focal Hematopoietic Marrow Depositions on MRI: Added Value of Proton Density Fat Fraction.

OBJECTIVE. The purpose of this study was to evaluate the added value of proton density fat fraction (PDFF) in differentiating vertebral metastases from focal hematopoietic marrow depositions. MATERIALS AND METHODS. The study included 44 patients with 30 vertebral metastases and 14 focal hematopoietic marrow depositions who underwent spinal MRI. The final diagnoses were based on histologic confirmation, follow-up MRI, or PET/CT. Two musculoskeletal radiologists with 1 and 15 years of experience independently interpreted both image sets (i.e., images from conventional MRI alone versus images from conventional MRI and PDFF combined). Using a 5-point scale, the readers scored their confidence in the malignancy of the vertebral lesions. The diagnostic performance (AUC) of the two image sets was assessed via ROC curve analyses. Sensitivities, specificities, and accuracies (for both image sets) were compared using the McNemar test. Kappa coefficients were calculated to assess interobserver agreement. RESULTS. Both readers showed improved diagnostic performance after PDFF was added (AUC, 0.840-0.912 and 0.805-0.895 for readers 1 and 2, respectively). However, adding PDFF did not significantly improve the sensitivity and specificity of either reader (p > .05). Interobserver agreement significantly improved from moderate (κ = 0.563) to excellent (κ = 0.947) after PDFF was added. CONCLUSION. The addition of PDFF to a conventional MRI protocol improved the diagnostic performance for differentiating vertebral metastases from focal hematopoietic marrow depositions but without resulting in significant improvement in sensitivity and specificity.

Triangular Osteosynthesis Using an S1 Pedicle Screw and S2 Alar Iliac Screw for a Unilateral Vertically Displaced Sacral Fracture.

BACKGROUND: Managing unilateral vertically displaced sacral fractures remains a challenge. A triangular osteosynthesis (TOS), which involves fixing the fractured sacrum using unilateral spinopelvic fixation and a supplemental ilio-sacral screw, continues to gain popularity as it facilitates early mobilization and improves the long-term outcome. However, it has limitations, such as destruction of the L5-S1 joint, the need for additional removal surgery, and an increased risk of infection due to the large incision. An S1 pediculoiliac construct was proposed to overcome this limitations. Its use also has complications, however, including a painful hardware prominence due to the traditional iliac screw, excessive soft tissue retraction, and limited reduction capability. CASE DESCRIPTION: A 20-year-old woman fell from a height of 6 meters and sustained a vertical shear type sacral fracture on the left side with substantial vertical displacement. We reduced and fixed the fracture using a TOS using an S1 pedicle screw and an S2 alar iliac screw (S2AIS). The patient was allowed immediate weight-bearing as tolerated. We achieved good reduction and union with a small vertical incision, without the destruction of L5-S1 joints, a symptomatic implant prominence, or wound complications. CONCLUSIONS: For unilateral vertically unstable sacral fractures, TOS using S1 pedicle screws and S2AIS is safe and has the advantage such as maintaining mobility in the lumbar pelvic region, small size wounds, and reduced soft tissue damage, and it may have a potentially low infection rate. Further studies are needed to determine the specific indications and validate the effectiveness of this procedure.

Differences in lumbar segment angle among Roussouly types of global sagittal alignment in asymptomatic adult subjects.

STUDY DESIGN: A radiological study. OBJECTIVES: To examine lumbar segment angle according to the Roussouly type of global sagittal alignment and to determine the reference disc angles in minimally invasive surgery (MIS) for adult spinal deformity. Optimal restoration of lumbar lordosis (LL) in adult spinal deformity surgery includes achieving the ideal shape of LL as well as the amount of LL. However, the distribution of lumbar segment angles by the Roussouly type has yet to be elucidated. METHODS: Forty sets of whole spine lateral radiographs covering the four Roussouly types (N = 160) were obtained from a database of asymptomatic adult subjects. Global and spinopelvic parameters were measured. Disc and vertebral angles at each lumbar level were compared among the Roussouly types. RESULTS: There were 75 (46.9%) men with a mean age of 32.8 ± 8.9 years among the total of 160 study subjects. A significant difference was found in spino-sacral angle, sacral slope, pelvic incidence, LL, and lower arc of LL (L4S1) among the Roussouly types (all P < 0.001). The ratio of the lower arc of LL (L4S1) to LL was 83.4% in Roussouly type 1, 65.2% in type 2, 64.7% in type 3, and 61.5% in type 4. The disc angles at the L1-2 and L2-3 levels in Roussouly type 1 were significantly smaller than in the other types. The disc angle at the L5-S1 level in Roussouly type 1 was significantly larger than that in type 2. Roussouly type 4 had a larger disc angle at the L2-3 and L4-5 levels than types 1 and 2. CONCLUSIONS: The results of this study showed that the disc angle distribution differs among Roussouly types. The configuration of LL as well as the amount of LL should be considered in adult spinal deformity surgery. LEVEL OF EVIDENCE: Level IV.

Does Mechanical Bowel Preparation Ameliorate Surgical Performance in Anterior Lumbar Interbody Fusion?

STUDY DESIGN: Retrospective case-control study. OBJECTIVES: To investigate whether mechanical bowel preparation (MBP) improve surgical performance and decrease operative complications in anterior lumbar interbody fusion (ALIF). METHODS: This study involved a retrospective analysis of 48 consecutive patients who underwent ALIF with MBP and a control cohort of 50 consecutive patients who underwent the same surgeries without MBP. The quality of each surgical procedure, operative time, estimated blood loss (EBL), intraoperative complications, changes in vital signs and patient symptoms on the day of surgery, and bowel function postoperatively were also compared between the procedures. RESULTS: Baseline demographic characteristics were similar between the 2 groups (all Ps > .05). The quality of each procedure, operative time, EBL, intraoperative complications, and changes in body temperature and heart rate were not different between the groups (all Ps > .05). The MBP group showed more headache, tiredness, thirst, and abdominal discomfort (all Ps < .001) and decrease of the systolic blood pressure (P = .041) on the day of surgery. The return of bowel movement was not different between the groups (P = .278). CONCLUSIONS: Given the similar surgical result with the substantial patient discomfort, MBP can be omitted in ALIF.

Complications After Multiple-Site Peripheral Nerve Blocks for Foot and Ankle Surgery Compared With Popliteal Sciatic Nerve Block Alone.

BACKGROUND: Single or combined multiple-site peripheral nerve blocks (PNBs) are becoming popular for patients undergoing surgery on their feet or ankles. These procedures are known to be generally safe in surgical settings compared with other forms of anesthesia, such as spinal block. The purposes of this study were to assess the incidence of complications after the administration of multiple PNBs for foot and ankle surgery and to compare the rates of complications between patients who received a single PNB and those who received multiple blocks. METHODS: Charts were reviewed retrospectively to assess peri- and postoperative complications possibly related to the PNBs. The records of 827 patients who had received sciatic nerve blocks, femoral nerve blocks adductor canal blocks, or combinations of these for foot and/or ankle surgery were analyzed for complications. The collected data consisted of age, sex, body mass index, presence of diabetes mellitus, smoking history, tourniquet time, and complications both immediately postoperatively and 1 year later. RESULTS: Of these 827 patients, 92 (11.1%) developed neurologic symptoms after surgery; 22 (2.7%) of these likely resulted from the nerve blocks, and 7 (0.8%) of these were unresolved after the patients' last follow-up visits. There were no differences in complication rates between combined blocks and single sciatic nerve blocks. CONCLUSION: There were more complications, both transient and long term, after anesthetic PNBs than previous literature has reported. Combined multiple-site blocks did not increase the rate of neurologic complications. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Use of an Alternative Surgical Corridor in Oblique Lateral Interbody Fusion at the L5-S1 Segment: A Technical Report.

STUDY DESIGN: Technical report. OBJECTIVE: To demonstrate the use of an alternative surgical corridor in oblique lateral interbody fusion (OLIF) at the L5-S1 segment. SUMMARY OF BACKGROUND DATA: OLIF L5-S1 is essentially performed through the central disk space between the bifurcations of the iliac vessels, which is sometimes difficult due to the vascular structures that obstruct the surgical field. Another concern is retrograde ejaculation following superior hypogastric plexus injury in male patients. MATERIALS AND METHODS: The alternative surgical corridor involves the lateral disk space external to the left iliac vessels. The patient position and the retroperitoneal approach are similar to those used in the conventional OLIF L5-S1. The left iliac vessels are identified and mobilized medially to the midline of the L5-S1 disk space. The vascular structures are then protected using the conventional OLIF 51 retractor system. RESULTS: Six patients underwent OLIF L5-S1 through the alternative lateral surgical corridor. The L5-S1 disk spaces were always exposed sufficiently for disk preparation and cage insertion. The postoperative radiographs showed a satisfactory L5-S1 reconstruction with good cage position. There were no perioperative complications during the surgical access and reconstruction procedures. CONCLUSIONS: When the central approach to the L5-S1 disk space poses a risk of vascular or superior hypogastric plexus injury, use of a lateral approach external to the left iliac vessels can be an alternative method to perform OLIF L5-S1.

Is Preexisting Cervical Disk Degeneration a Prognostic Factor in Whiplash-associated Disorders?

STUDY DESIGN: This is a retrospective control study. OBJECTIVE: We aimed to determine whether preexisting cervical disk degeneration is a prognostic factor in Whiplash-associated disorder (WAD). SUMMARY OF BACKGROUND DATA: WAD is a common injury of traffic accident and has a broad range of prognoses. Although numerous studies have investigated prognostic factors in WAD, few have evaluated the effect of preexisting disk degeneration. MATERIALS AND METHODS: This study involved 45 consecutive patients with grade I or II WAD having advanced disk degeneration (at least 1 disk of Miyazaki grade≥III on magnetic resonance imaging) and a control cohort of 52 patients with no or mild disk degeneration (all disks having Miyazaki grades≤II). Clinical assessment included pain severity (assessed by the visual analog scale), neck pain-related disability (assessed by the neck disability index), and physical and mental health condition [assessed by the short-form 36 (SF-36) physical composite score and SF-36 mental composite score, respectively]. Changes in each parameter were evaluated at baseline and at 3-month, 6-month, and 1-year follow-ups and compared between the 2 groups. RESULTS: There were no differences between the 2 groups regarding demographics and baseline outcome parameters (all P>0.05). There were also no differences in improvement in visual analog scale for neck pain, neck disability index, SF-36 physical composite score, or SF-36 mental composite score between the 2 groups (all P>0.05) for each visit. The number of claim closures was significantly lower among patients with advanced degeneration than among controls at 6-month and 1-year follow-ups (P=0.004 and 0.006, respectively). CONCLUSIONS: In the present study, the clinical presentation and prognosis of WAD were not affected by preexisting disk degeneration. However, claim closure was delayed in patients with preexisting disk degeneration. These results suggest that misunderstanding of disk degeneration on magnetic resonance imaging may create persistent illness and lead to continued compensation in WAD.

Measurement of Spinopelvic Parameters on Standing Lateral Lumbar Radiographs: Validity and Reliability.

STUDY DESIGN: This was a radiographic validity and reliability study. OBJECTIVE: We assessed the validity and reliability of measurements made on standing lateral lumbar radiographs, compared with lateral whole-spine radiographs, for evaluating spinopelvic parameters and lumbar lordosis (LL). SUMMARY OF BACKGROUND DATA: A lateral whole-spine radiograph is the gold standard image for measurement of spinopelvic parameters. However, little evidence is available on the reliability of measurements made on such radiograph. A standing lateral lumbar radiograph is routinely obtained from patients with back pain and/or a disability. This image can include upper end plate of L1 vertebra, sacral dome and both femoral heads. Thus, this radiograph can be used for evaluation of spinopelvic parameters. MATERIALS AND METHODS: We randomly selected 50 sets of digital radiographs (standing lateral lumbar and lateral whole-spine radiographs) from our database. Three experienced spinal surgeons independently measured LL, pelvic incidence, pelvic tilt, and sacral slope on all images. A paired t test and Pearson correlation was used to analyze the validity of the lateral lumbar radiograph. Interobserver and intraobserver reliabilities were assessed by intraclass correlation coefficient. RESULTS: Thee spinopelvic parameters and LL measured on lateral lumbar radiographs were similar to those measured on lateral whole-spine radiographs (All P-values >0.05, Pearson correlation coefficients, 0.807-0.969). The intraobserver and interobserver reproducibilities of both measurement types were good-to-excellent. CONCLUSIONS: Spinopelvic parameters and LL values measured on lateral lumbar radiographs were reproducibly similar to those measured on lateral whole-spine radiographs. Use of a standing lateral lumbar radiograph is reasonable when spinopelvic parameters and LL are to be measured.

Cost-Utility Analysis of Pedicle Screw Removal After Successful Posterior Instrumented Fusion in Thoracolumbar Burst Fractures.

STUDY DESIGN: A cost-utility analysis (CUA). OBJECTIVE: The aim of this study was to determine the cost-effectiveness of pedicle screw removal after posterior fusion in thoracolumbar burst fractures. SUMMARY OF BACKGROUND DATA: Pedicle screw instrumentation is a standard fixation method for unstable thoracolumbar burst fracture. However, removal of the pedicle screw after successful fusion remains controversial because the clinical benefits remain unclear. CUA can help clinicians make appropriate decisions about optimal health care for pedicle screw removal after successful fusion in thoracolumbar burst fractures. METHODS: We conducted a single-center, retrospective, longitudinal matched-cohort study of prospectively collected outcomes. In total, 88 consecutive patients who had undergone pedicle screw instrumentation for thoracolumbar burst fracture with successful fusion confirmed by computed tomography (CT) were used in this study. In total, 45 patients wanted to undergo implant removal surgery (R group), and 43 decided not to remove the implant (NR group). A CUA was conducted from the health care perspective. The direct costs of health care were obtained from the medical bill of each patient. Changes in health-related quality of life (HRQoL) scores, validated by Short Form 6D, were used to calculate quality-adjusted life-years (QALYs). Total costs and gained QALY were calculated at 1 year (1 year) and 2 years (2 years) compared with baseline. Results are expressed as an incremental cost-effectiveness ratio (ICER). Different discount rates (0%, 3%, and 5%) were applied to both cost and QALY for sensitivity analysis. RESULTS: Baseline patient variables were similar between the two groups (all P > 0.05). The additional benefits of implant removal (0.201 QALY at 2 years) were achieved with additional costs ($2541 at 2 years), equating to an ICER of $12,641/QALY. On the basis of the different discount rates, the robustness of our study's results was also determined. CONCLUSION: Implant removal after successful fusion in a thoracolumbar burst fracture is cost-effective until postoperative year 2. LEVEL OF EVIDENCE: 3.

Is It Beneficial to Remove the Pedicle Screw Instrument After Successful Posterior Fusion of Thoracolumbar Burst Fractures?

STUDY DESIGN: Case-control study. OBJECTIVE: To investigate the clinical and radiological outcomes of pedicle screw removal after successful fusion of thoracolumbar burst fractures. SUMMARY OF BACKGROUND DATA: Implant removal is a common procedure in orthopedic surgery, although the benefits of and indications for removal remain controversial. Previous studies on pedicle screw removal have reported conflicting outcomes, because the study subjects and surgical goals were heterogeneous in nature. METHODS: We studied 45 consecutive patients who underwent implant removal and a control cohort of 45 age- and sex-matched patients who retained their spinal implants after successful posterior fusion of thoracolumbar burst fractures using pedicle screw instrument. In most cases, long-segment instrumentation with short-segment posterior fusion was performed. The mean elapsed period prior to implant removal after index fracture surgery was 18.3 ± 17.6 months. A visual analogue scale for back pain was applied, the Oswestry disability index calculated, and radiological parameters derived at the time of implant removal and 1 and 2 years postoperatively obtained. These data were compared with those of the control group evaluated at the same times after index fracture surgery. RESULTS: Patient demographics, mechanisms of injury, fracture morphologies, and the outcomes of index fracture surgery were similar between the 2 groups. The mean visual analogue scale and Oswestry disability index scores were better at both the 1- and 2-year follow-ups in the implant removal group than in the control group (all P values = 0.000). The segmental motion angle of the implant removal group was 1.6° ± 1.5° at the time of implant removal, and increased significantly to 5.8° ± 3.9° at 1-year follow-up (P = 0.000), and was maintained at this level at the 2-year follow-up (5.9° ± 4.1°) (P = 0.000). CONCLUSION: In patients treated successfully for thoracolumbar burst fractures, pedicle screw removal is beneficial because it alleviates pain and disability. Restoration of the segmental motion angle after implant removal may contribute to the clinical improvement. LEVEL OF EVIDENCE: 3.