Serial changes in trunk muscle performance after posterior lumbar surgery

Impact of iatrogenic alterations on adjacent segment degeneration after lumbar fusion surgery: a systematic review

PURPOSE

Adjacent segment degeneration (ASDeg) and disease (ASDis) remain significant challenges following lumbar spinal fusion surgery, with reported incidences of 36% for ASDeg and 11% for ASDis within two to seven years post-operation. However, the mechanisms leading to the development of ASDeg are still poorly understood. This comprehensive review aims to elucidate the multifactorial etiology of ASDeg by examining important iatrogenic alterations associated with spinal fusion.

METHODS

A systematic review following PRISMA guidelines was conducted to identify clinical studies quantifying the occurrence of ASDeg and ASDis after lumbar fusion surgery. An EMBASE and citation search up to April 2023 yielded 378 articles. Data extracted encompassed study design, fusion type, sample size, patient age, and incidence of ASDeg and ASDis. A total of 87 publications were analyzed in the context of iatrogenic alterations caused by surgical access (muscle damage, ligament damage, facet joint damage) and instrumentation (fusion angle, immobilization).

RESULTS

Ligament damage emerged as the most impactful iatrogenic factor promoting ASDeg and ASDis development. Similarly, muscle damage had a significant impact on long-term musculoskeletal health, with muscle-sparing approaches potentially reducing ASDis rates. Immobilization led to compensatory increased motion at adjacent segments; however, the causal link to degeneration remains inconclusive. Fusion angle showed low evidence for a strong impact due to inconsistent findings across studies. Facet joint violations were likely contributing factors but not primary initiators of ASDeg.

CONCLUSION

Based on the analyzed literature, ligament and muscle damage are the most impactful iatrogenic factors contributing to ASDeg and ASDis development. Minimally invasive techniques, careful retractor placement, and ligament-preserving decompression may help mitigate these effects by reducing undue muscle and ligament trauma. Although it is not possible to definitively advocate for one or more techniques, the principle of selecting the most tissue-sparing approach needs to be scaled across surgical planning and execution. Further research is necessary to fully elucidate these mechanisms and inform surgical practices to mitigate ASDeg risk.

The Paraspinal Sarcopenia at the Upper Instrumented Vertebra Is a Predictor of Discoligamentous but Not Bony Proximal Junctional Kyphosis

Background/Objectives: Both poor bone quality and paraspinal sarcopenia have been suggested as risk factors for proximal junctional kyphosis (PJK) at the upper instrumented vertebra (UIV) following long-segment thoracolumbar fusion. Methods: Adults ≥50 with a T1-6 UIV were identified, and data were gathered on pre- and postoperative spinopelvic parameters, bone quality (using Hounsfield units and vertebral bone quality score), and paraspinal cross-sectional area at L3 and the UIV. PJK was defined by a ≥10° increase in the proximal junctional angle. Cox regressions were performed to identify PJK risk factors; PJK was subdivided into types 1-3 based on the Yagi-Boachie classification. Results: In total, 15/76 patients (median age 66; 72.4% female) experienced PJK; 10 experienced type 1, 4 experienced type 2, and one experienced type 3. Univariable Cox regression showed that PJK was negatively correlated with total paraspinal muscle CSA at the UIV (HR 0.74/100 mm2; 95% CI [0.57, 0.6]; p = 0.02). Lower total paraspinal CSA at L3 (HR 0.94/100 mm2; p = 0.07) and higher postoperative global tilt (HR 1.03; p = 0.09) also trended toward significance. Similarly, type 1 PJK was predicted by smaller total paraspinal CSA at the UIV (HR 0.64/100 mm2; [0.45, 0.92]; p = 0.02). Paraspinal CSA was not predictive of type 2 PJK, but lower HU at the UIV and UIV + 1 trended toward significance (HR 0.98/unit; p = 0.16). A comparison of type 1 and 2 PJK showed a higher average of paraspinal CSA and a lower average of HU at the UIV. Conclusions: Global alignment and paraspinal sarcopenia were most predictive of PJK, though paraspinal sarcopenia was only predictive of type 1. Type 2 may be better predicted by bone quality.

Biomechanical Evaluation of the Effect of MIS and COS Surgical Techniques on Patients with Spondylolisthesis using a Musculoskeletal Model

Background

The biomechanical impacts of Conventional Open Surgery (COS) versus Minimally Invasive Surgery (MIS) fusion techniques on adjacent segments and their potential role in developing Adjacent Segment Disease (ASD) remain uncertain for spondylolisthesis.

Objective

This study aimed to investigate the impact of MIS and COS fusion surgeries on adjacent spinal segments for spondylolisthesis, through on muscle injury and developing ASD.

Material and Methods

This prospective and non-randomized controls study used a validated musculoskeletal model to compare the biomechanical effects of COS and MIS L4/L5 fusion surgery on patients with spondylolisthesis. The model incorporated kinematic data from 30 patients who underwent each surgery. A sitting task was simulated to model post-operative muscle atrophy, and the analysis focused on changes in biomechanics of adjacent spinal segments.

Results

Lumbar flexion was significantly greater (201%) in MIS vs. COS, despite similar pelvic tilt. Consequently, Lumbopelvic Rhythm (LPR) also increased in MIS (133%). Both techniques altered inter-segmental moments. While inter-joint load was higher in COS, only the lower joint's compressive load was significantly greater (67%). Additionally, MIS required lower overall muscle force with reduced loads and passive moment on spinal joints compared to COS.

Conclusion

This study demonstrates that MIS fusion preserves physiological LPR better than COS. MIS maintains normal spinal curvature and maintains lumbar lordosis. While open surgery can lead to abnormal curvature and increased muscle forces to compensate for spinal stability. The study emphasizes the importance of paraspinal muscles in influencing spinal load distribution during MIS compare to COS.

Comparison of clinical and radiologic outcomes between biportal endoscopic transforaminal lumbar interbody fusion and posterior lumbar interbody fusion

Biportal endoscopic spinal surgery has become increasingly popular, and indications have expanded. Among these, biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) has yielded good results. Herein, we compared the clinical and radiological outcomes of 155 patients treated with BE-TLIF and open posterior lumbar interbody fusion (PLIF) for single-level lumbar degenerative diseases. Clinical outcomes included the visual analog scale for the back (VAS-back) and leg (VAS-leg), Oswestry Disability Index, and EuroQol 5-Dimensions. Radiological parameters and fusion rates were evaluated, and postoperative complications were recorded. In this cohort 68 and 87 patients were treated with BE-TLIF and PLIF, respectively. Both groups showed significant improvements in all clinical parameters compared with baseline, but BE-TLIF exhibited a more significant improvement in VAS-back at 1 and 6 months postoperatively. There were no significant differences in the radiological parameters or fusion rates. BE-TLIF had a significantly longer operation time, whereas PLIF exhibited a significantly higher estimated blood loss and surgical drainage, but no significant differences in postoperative complications. Compared to PLIF, BE-TLIF showed similarly good clinical and radiologic outcomes, with better results in terms of early postoperative outcomes. Thus, BE-TLIF is a viable alternative to PLIF with less back pain at 1 and 6 months postoperatively.

Trans-Pars Interarticularis Approach for Lumbar Interbody Fusion: An Efficient, Straightforward, and Minimally Invasive Surgery for Lumbar Spondylolisthesis and Stenosis

BACKGROUND

 Lumbar interbody fusion is a commonly applied surgical treatment for spondylolisthesis. For this procedure, various minimally invasive (MIS) approaches have been developed, including posterior lumbar interbody fusion, transforaminal lumbar interbody fusion (TLIF), oblique lumbar interbody fusion, and anterior lumbar interbody fusion. In this study, we characterized the features of an MIS trans-pars interarticularis lumbar interbody fusion (TPLIF) and compared its surgical outcomes with those of MIS-TLIF.

METHODS

 This study included 89 and 44 patients who had undergone MIS-TPLIF and MIS-TLIF, respectively, between September 2016 and December 2022. The following clinical outcomes were analyzed: operative time, blood loss, and hospitalization duration.

RESULTS

 The average operative time, blood loss, and hospitalization duration for the MIS-TPLIF and MIS-TLIF groups were, respectively, 98.28 and 191.15 minutes, 41.97 and 101.85 mL, and 5.8 and 6.9 days.

CONCLUSION

 The MIS-TPLIF approach for lumbar spondylolisthesis or other degenerative diseases involves the use of the commonly available and cost-effective instrument Taylor retractor, thus enabling posterior lumbar interbody fusion to be performed with minimal invasion. This approach also confers the benefits of a short learning curve and an intuitive approach. Our results suggest that although MIS-TPLIF is noninferior to MIS-TLIF, it is easier to learn and perform than MIS-TLIF.

The effectiveness of short hybrid stabilization with sublaminar bands and transpedicular screws in the treatment of thoracolumbar spine fractures

BACKGROUND

Long constructs have always been widely recommended for the treatment of thoracolumbar fractures, due to their biomechanical stability and minimal postoperative loss of correction. However, short constructs have significant advantages, since they enable for better postoperative lumbar mobility and reduce the risk of adjacent segment degeneration. The purpose of this study is to evaluate the safety and efficacy of hybrid screw/sublaminar bands short constructs, used for the treatment of thoracolumbar fractures.

METHODS

From June 2015 until November 2017, 20 consecutive patients (14 male, 6 female) with an average age of 52.9 years, exhibiting at least one traumatic fracture in the thoracolumbar region, were treated with hybrid screw/sublaminar bands short constructs. The data for analysis included: duration of the intervention, intraoperative blood loss, complications, and clinical and radiographic postoperative results, compared with the standard for thoracolumbar fixation.

RESULTS

The use of this type of construct allowed for simple reduction, stabilization of the fractures, and restoration of the physiological spine curvatures. During the postoperative period none of the patients had neurological worsening. 18 out of 20 patients were followed up for two years. One patient sustained implant failure six months after surgery and underwent a surgical implant revision with traditional long fixation. After two years, stability and fusion were obtained in all patients, along with correct spine alignment.

CONCLUSIONS

Hybrid screw/sublaminar bands short constructs seem to be effective in the treatment of thoracolumbar fractures, providing the same clinical results of the state-of-the-art pedicular screw/rod long constructs, but in addition they allow for better postoperative lumbar mobility and subsequently reduce the risk of adjacent segments degeneration. The results of this clinical case series might support the initiation of prospective randomized trials with more patients, a longer follow-up period, and control groups.

Robotic endoscopic transforaminal lumbar interbody fusion: A single institution case series

Background

Robotic-assisted, endoscopic transforaminal lumbar interbody fusion (RE-TLIF) is a promising, minimally invasive surgical option for degenerative lumbar spondylosis/spondylolisthesis; however, outcomes data and efficacy are limited, especially in multilevel disease. Here, we present the first reported series of patients that underwent either single or multilevel RE-TLIF.

Methods

A retrospective review was performed on 23 consecutive patients who underwent a single level or multilevel RE-TLIF by a single surgeon. Variables included demographics, perioperative results, pain scores, and functional outcome scores.

Results

Eighteen patients (78.3 %) underwent single level RE-TLIF and 5 patients (21.7 %) underwent multilevel RE-TLIF. The median reduction of visual analog scale (VAS) for low back pain (LBP) of all subjects was 6 (IQR = 4.5, 6.5) with no significant difference between single level and multilevel RE-TLIF (p = 0.565). The median reduction of VAS for leg pain of all subjects 7 (IQR = 6, 8) with no significant difference between single level and multilevel RE-TLIF (p = 0.702). Median blood loss was 25 cc (IQR = 25, 25) and 50 cc (IQR = 25, 100) for single and multilevel RE-TLIF, respectively (p = 0.025), whereas median length of stay was 1 (IQR = 1, 1; mean = 1.0 ± 00.18) days and 1 (IQR = 1, 2; mean = 1.4 ± 00.54) days, respectively (p = 0.042). One major complication was observed requiring reoperation for demineralized bone matrix migration resulting in an L5 radiculopathy.

Conclusions

Single and multi-level RE-TLIF appears to be a safe and efficacious approach with comparable outcomes to open and other minimally invasive approaches. Additionally, we observed favorable accuracy in robot-assisted pedicle screw, endoscope, and interbody device placement.

Failed back surgery syndrome-terminology, etiology, prevention, evaluation, and management: a narrative review

Amid the worldwide increase in spinal surgery rates, a significant proportion of patients continue to experience refractory chronic pain, resulting in reduced quality of life and escalated healthcare demands. Failed back surgery syndrome (FBSS) is a clinical condition characterized by persistent or recurrent pain after one or more spinal surgeries. The diverse characteristics and stigmatizing descriptions of FBSS necessitate a reevaluation of its nomenclature to reflect its complexity more accurately. Accurate identification of the cause of FBSS is hampered by the complex nature of the syndrome and limitations of current diagnostic labels. Management requires a multidisciplinary approach that may include pharmacological treatment, physical therapy, psychological support, and interventional procedures, emphasizing realistic goal-setting and patient education. Further research is needed to increase our understanding, improve diagnostic accuracy, and develop more effective management strategies.

Meta-analysis of the efficacy and safety of OLIF and TLIF in the treatment of degenerative lumbar spondylolisthesis

OBJECTIVE

To systematically evaluate the difference in clinical efficacy between two surgical approaches, oblique lateral approach and intervertebral foraminal approach, in the treatment of degenerative lumbar spondylolisthesis.

METHODS

English databases, including PubMed, Cochrane, Embase, and Web of Science, were systematically searched using keywords such as "oblique lumbar interbody fusion" and "transforaminal lumbar interbody fusion." Concurrently, Chinese databases, including CNKI, WanFang data, VIP, and CBM, were also queried using corresponding Chinese terms. The search spanned from January 2014 to February 2024, focusing on published studies in both Chinese and English that compared the clinical efficacy of OLIF and TLIF. The literature screening was conducted by reviewing titles, abstracts, and full texts. Literature meeting the inclusion criteria underwent quality assessment, and relevant data were extracted. Statistical analysis and a meta-analysis of the observational data for both surgical groups were performed using Excel and RevMan 5.4 software. Findings revealed a total of 14 studies meeting the inclusion criteria, encompassing 877 patients. Of these, 414 patients were in the OLIF group, while 463 were in the TLIF group. Meta-analysis of the statistical data revealed that compared to TLIF, OLIF had a shorter average surgical duration (P < 0.05), reduced intraoperative bleeding (P < 0.05), shorter average hospital stay (P < 0.05), better improvement in postoperative VAS scores (P < 0.05), superior enhancement in postoperative ODI scores (P < 0.05), more effective restoration of disc height (P < 0.05), and better correction of lumbar lordosis (P < 0.05). However, there were no significant differences between OLIF and TLIF in terms of the incidence of surgical complications (P > 0.05) and fusion rates (P > 0.05).

CONCLUSION

When treating degenerative lumbar spondylolisthesis, OLIF demonstrates significant advantages over TLIF in terms of shorter surgical duration, reduced intraoperative bleeding, shorter hospital stay, superior improvement in postoperative VAS and ODI scores, better restoration of disc height, and more effective correction of lumbar lordosis.

Comparison of a novel hand-held retractor-assisted transforaminal lumbar interbody fusion by the wiltse approach and posterior TLIF: a one-year prospective controlled study

BACKGROUND

This study aims to compare the clinical outcomes and safety of a novel hand-held retractor system-assisted Wiltse TLIF with that P-TLIF and assess whether this hand-held retractor system assisted Wiltse TLIF can yield less paraspinal muscle injury.

METHODS

56 patients (P-TLIF: 26, Wiltse TLIF: 30) were included in this one year prospective controlled study. The operation time, intraoperative blood loss, postoperative drainage, mobilization time, and discharge time were recorded. The clinical outcomes were evaluated by ODI, VAS, JOA, and SF-36 scores (7 days, 3, 6, and 12 months after surgery). Paraspinal muscle injury was assessed by postoperative MRI (6 months after surgery). CK and C-reaction protein were measured pre and postoperatively, and CT or X-ray (one year postoperatively) was used to assess bony union/non-union.

RESULTS

The Wiltse (study) group was associated with significantly less estimated blood loss (79.67 ± 28.59 ml vs 192.31 ± 59.48 ml, P = 0.000*), postoperative drainage (43.33 ± 27.89 ml vs 285.57 ± 123.05 ml, P = 0.000*), and shorter mobilization (4.1 ± 1.2 d vs. 3.0 ± 0.9 d, P < 0.05) and discharge times (7.7 ± 1.9 d vs. 6.1 ± 1.2 d, P = 0.002*) than the P-TLIF (control) group. Serum CK activity at 24 h postoperatively in the study group was significantly lower than in the control group (384.10 ± 141.99 U/L vs 532.76 ± 225.76 U/L, P = 0.018*). At 7 days after surgery, VAS (2.3 ± 0.6 vs 3.2 ± 0.7, P = 0.000*)and ODI scores (43.9 ± 11.9 vs 55.2 ± 12.9, P = 0.001*) were lower, while the JOA scores (18.4 ± 3.4 vs 16.3 ± 4.2, P = 0.041*) was higher in the control group than in the study group. Results observed at 3 months of follow-up were consistent with those at 7 days. After six months postoperatively, paraspinal muscle degeneration in the control group was more significant than in the study group (P = 0.008*).

CONCLUSION

Our study showed that this novel hand-held retractor system assisted Wiltse approach TLIF can significantly reduce paraspinal muscle injury, postoperative drainage, and intraoperative blood loss, mobilization and discharge time, as well as yield better short-term outcomes compared to P-TLIF.

TRIAL REGISTRATION

25/09/2023 NCT06052579.

Magnetic Resonance Imaging Evaluation of Multifidus Muscle in Patients with Low Back Pain after Microlumbar Discectomy Surgery

Cross-sectional area (CSA) and signal intensity ratio (SIR) of the multifidus muscle (MFM) on magnetic resonance imaging (MRI) was used to evaluate the extent of injury and atrophy of the MFM in patients with negative treatment outcomes following microlumbar discectomy (MLD). Negative treatment outcome was determined by pain score improvement of <50% compared to baseline. Patients in groups 1, 2, and 3 were evaluated at <4 weeks, 4-24 weeks, and >24 weeks postoperatively, respectively. The associations between the follow-up, surgery time and the changes in the MFM were evaluated. A total of 79 patients were included, with 22, 27, and 30 subjects in groups 1, 2, and 3, respectively. The MFM SIR of the ipsilateral side had significantly decreased in groups 2 (p = 0.001) and 3 (p < 0.001). The ipsilateral MFM CSA significantly decreased postoperatively in groups 2 (p = 0.04) and 3 (p = 0.006). The postoperative MRI scans found significant MFM changes on the ipsilateral side in patients with negative treatment outcomes regarding pain intensity following MLD. As the interval to the postoperative MRI scan increased, the changes in CSA of the MFM and change in T2 SIR of the MFM showed a tendency to increase.

The effect of fatty infiltration, revision surgery, and sex on lumbar multifidus passive mechanical properties

Purpose

Previous research has demonstrated increased stiffness in the multifidus muscle compared to other paraspinal muscles at the fiber bundle level. We aimed to compare single fiber and fiber bundle passive mechanical properties of multifidus muscle: (1) in 40 patients undergoing primary versus revision surgery and (2) in muscle with mild versus severe fatty infiltration.

Methods

The degree of muscle fatty infiltration was graded using the patients' spine magnetic resonance images. Average single fiber and fiber bundle passive mechanical properties across three tests were compared between primary (N = 30) and revision (N = 10) surgery status, between mild and severe fatty infiltration levels, between sexes, and with age from passive stress-strain tests of excised multifidus muscle intraoperative biopsies.

Results

At the single fiber level, elastic modulus was unaffected by degree of fatty infiltration or surgery status. Female sex (p = 0.001) and younger age (p = 0.04) were associated with lower multifidus fiber elastic modulus. At the fiber bundle level, which includes connective tissue around fibers, severe fatty infiltration (p = 0.01) and younger age (p = 0.06) were associated with lower elastic modulus. Primary surgery also demonstrated a moderate, but non-significant effect for lower elastic modulus (p = 0.10).

Conclusions

Our results demonstrate that female sex is the primary driver for reduced single fiber elastic modulus of the multifidus, while severity of fatty infiltration is the primary driver for reduced elastic modulus at the level of the fiber bundle in individuals with lumbar spine pathology.

Radiological Assessment of Postoperative Paraspinal Muscle Changes After Lumbar Interbody Fusion With or Without Minimally Invasive Techniques

STUDY DESIGN

Retrospective cohort study.

BACKGROUND

Percutaneous pedicle screws (PPS) have the advantage of being able to better preserve the paraspinal muscles when compared with a traditional open approach. However, the nature of changes in postoperative paraspinal muscle after damage by lumbar fusion surgery has remained largely unknown. It is clinically important to clarify and compare changes in paraspinal muscles after the various surgeries.

OBJECTIVE

(1) To determine postoperative changes of muscle density and cross-sectional area using computed tomography (CT), and (2) to compare paraspinal muscle changes after posterior lumbar interbody fusion (PLIF) with traditional open approaches and minimally invasive lateral lumbar interbody fusions (LLIF) with PPS.

METHODS

We included data from 39 consecutive female patients who underwent open PLIF and 23 consecutive patients who underwent single-staged treatment with LLIF followed by posterior PPS fixation at a single level (L4-5). All patients underwent preoperative, 6 months postoperative, and 1-year postoperative CT imaging. Measurements of the cross-sectional area (CSA) and muscle densities of paraspinal muscles were obtained using regions of interest defined by manual tracing.

RESULTS

We did not find any decrease of CSA in any paraspinal muscles. We did find a decrease of muscle density in the multifidus at 1 year after surgery in patients in the PILF group, but not in those in LLIF/PPS group.

CONCLUSIONS

One year after surgery, a significant postoperative decrease of muscle density of the multifidi was observed only in patients who underwent open PLIF, but not in those who underwent LLIF/PPS.

Patient reported outcomes after navigated minimally invasive hybrid lumbar interbody fusion (nMIS-HLIF) using cortical bone trajectory screws

Prospective observational study. To evaluate patient-reported outcomes after navigation-guided minimally invasive hybrid lumbar interbody fusion (nMIS-HLIF) for decompression and fusion in degenerative spondylolisthesis (Meyerding grade I-II). Posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) are well-known standard procedures for lumbar spinal fusion. nMIS-HLIF is a navigation-guided combined percutaneous and open procedure that combines the advantages of PLIF and TLIF procedures for the preparation of a single-port endoscopic approach. 33 patients underwent nMIS-HLIF. Core outcome measure index (COMI), oswestry disability index (ODI), numeric rating scale (NRS) back, NRS leg, and short form health-36 (SF-36) were collected preoperatively and at follow-up of 6 weeks, 3 months, 6 months, and 1 year. The impact of body mass index (BMI) was also analyzed. Computed tomography reconstruction was used to assess realignment and verify fused facet joints and vertebral bodies at the 1-year follow-up. 28 (85%) completed the 1-year follow-up. The median BMI was 27.6 kg/m2, age 69 yrs. The mean reduction in listhesis was 8.4% (P < .01). BMI was negatively correlated with listhesis reduction (P = .032). The improvements in the NRS back, NRS leg, ODI, and COMI scores were significant at all times (P < .001-P < .01). The SF-36 parameters of bodily pain, physical functioning, physical component summary, role functioning/physical functioning, and social functioning improved (P < .003). The complication rate was 15.2% (n = 5), with durotomy (n = 3) being the most frequent. To reduce the complication rate and allow transitioning to a fully endoscopic approach, expandable devices have been developed. The outcomes of nMIS-HLIF are comparable to the current standard open and minimally invasive techniques. A high BMI hinders this reduction. The nMIS-HLIF procedure is appropriate for learning minimally invasive dorsal lumbar stabilization. The presented modifications will enable single-port endoscopic lumbar stabilization in the future.

Transforaminal Endoscopic Decompression for Foraminal Stenosis: Single-Arm Meta-Analysis and Systematic Review

OBJECTIVE

The objective of the study was to conduct a single-arm meta-analysis and comprehensive systematic review to identify the efficacy and safety of transforaminal endoscopic surgery for the treatment of lumbar foraminal stenosis (LFS).

METHODS

The meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The PubMed, Web of Science, and Embase databases were searched from inception to February 20, 2022. Primary research results were visual analog scale scores, Oswestry Disability Index scores, MacNab criterion scores, and reported adverse events. Subgroup analyses were performed on the primary outcome to evaluate the potential effects of several clinical factors that affected the results.

RESULTS

Of the 2020 studies identified, 9 met the inclusion criteria, and 316 participants were eligible for meta-analysis. The meta-analysis results found that transforaminal endoscopic surgery for the treatment of LFS was associated with a significant improvement in postoperative 12-month clinical indicators: 8 studies reported improvements in visual analog scale scores: -5.38, Oswestry Disability Index scores: -40.44, and MacNab criterion scores: odds ratio = 0.86; 8 studies reported 11.53% adverse events occurred in a total of 295 patients, and the most commonly reported event was transient postoperative dysesthesia, which occurred in 26 patients in a total of 6 studies with 240 patients (10.83%).

CONCLUSIONS

Transforaminal endoscopic surgery positively affects postoperative LFS patients' clinical indicators; however, high-level literature with randomized controlled trials is needed to confirm this technique's applicability in LFS.

Contralateral bridge fixation of freehand minimally invasive pedicle screws combined with unilateral MIS-TLIF vs. open TLIF in the treatment of multi-segmental lumbar degenerative diseases: A five years retrospective study and finite element analysis

OBJECTIVE

To evaluate the efficacy, safety, feasibility and biomechanical stability of contralateral bridge fixation of freehand minimally invasive pedicle screws (Freehand MIPS) combined with unilateral minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF) (smile-face surgery) and open TLIF for the treatment of multi-segmental lumbar degenerative diseases (LDDs).

METHODS

From January 2013 to January 2016, clinical data of multi-segmental (2- or 3-level) LDDs receiving smile-face surgery or open TLIF were retrospectively collected and analyzed. The back and leg pain VAS and ODI were used to assess clinical outcomes preoperatively and postoperatively. The MacNab criteria were used to evaluate the satisfaction of patient. The disc height (DH), lumbar lordosis (LL) and segmental lordosis angle (SLA) were measured before and after surgery. We used patient's CT data to establish the finite element model of smile-face surgery and open TLIF, and analyze biomechanical stability of two methods.

RESULTS

Smile-face surgery group showed shorter operation time, shorter incision, less blood loss, shorter hospital stay than open TLIF (P < 0.05). The back VAS in smile-face surgery group was significantly lower than that in open TLIF immediately and 3 months after surgery, and no significant difference was observed 1 year, 2 years and 5 years after surgery. There was no significant difference in the leg pain VAS and ODI between both groups after surgery. No significant difference was observed between two groups in the DH, LL and SLA. At 5-year follow-up, grade I or II fusion was achieved in 99.00% (100/101) segments of smile-face surgery group and 97.67% (84/86) segments of open TLIF group according to Bridwell system. The complication rate of open TLIF was higher than that of smile-face surgery (24.32% vs. 0%, P < 0.01). After verification, the established finite element model can accurately simulate the biological structure of lumbar spine and there was no significant difference in biomechanical stability between two methods.

CONCLUSIONS

Smile-face surgery has some advantages over open TLIF including smaller aggression, less blood loss, and lower cost, indicating that it is a good choice of treatment for multi-segmental LDDs. Both methods can achieve good biomechanical stability.

Postoperative Opioid Use Following Single-Level Transforaminal Lumbar Interbody Fusion Compared with Posterolateral Lumbar Fusion

OBJECTIVE

To compare postoperative opioid morphine milligram equivalents (MME) prescriptions for opioid-naïve patients undergoing single-level transforaminal lumbar interbody fusion (TLIF) versus posterolateral lumbar fusion (PLF) and total postoperative MME prescribed based on operative duration.

METHODS

Patients undergoing single-level TLIF or PLF from September 2017 to June 2020 were identified from a single institution. Patients were first grouped based on procedure type (TLIF or PLF) and subsequently regrouped based on median operative duration. Statistical tests compared patient demographics and opioid prescription data between groups. Multivariate regressions were performed to control for demographics, operative time, and procedure type.

RESULTS

Of 345 patients undergoing single-level PLF or TLIF, 174 (50.4%) were opioid-naïve; 101 opioid-naïve patients (58.0%) underwent PLF and 73 (42.0%) underwent TLIF. Patients undergoing TLIF received more opioid prescriptions (1.99 vs. 1.26, P < 0.001) and total MME (91.2 vs. 66.8, P = 0.002). After regrouping patients based on operative duration, independent of procedure type, there were no differences in postoperative opioid prescriptions, and Spearman rank correlation coefficient between total MME and operative duration was r = 0.014. Multivariate analysis identified TLIF as an independent predictor of increased postoperative opioid prescriptions (β = 0.64, P < 0.001), prescribers (β = 0.49, P = 0.003), and MME (β = 24.4, P = 0.030).

CONCLUSIONS

Opioid-naïve patients undergoing single-level TLIF receive a greater number of postoperative opioids than patients undergoing single-level PLF, and TLIF was an independent predictor of increased postoperative opioid prescribers, prescribers, and MME. There were no differences in postoperative opioid prescriptions when assessing patients based on operative duration.

Clinical Evaluation of Surgery for Single-Segment Lumbar Spinal Stenosis: A Systematic Review and Bayesian Network Meta-Analysis

To compare the efficacy and safety of different surgical procedures for patients with single‐segment lumbar spinal stenosis (LSS), Bayesian network meta‐analysis (NMA) was conducted in this study. Randomized controlled trials (RCTs) which reported 2 years' results after surgery were searched from PubMed, Embase, and Cochrane Register of Controlled Trials up to February 2021. Eligible RCTs that contained at least two of the following surgical procedures, bilateral decompression via the unilateral approach (BDUL), decompression with conventional laminectomy (CL), decompression with fusion (DF), endoscopic decompression (ED), interspinous process devices only (IPDs), decompression with interlaminar stabilization (DILS), decompression with lumbar spinal process‐splitting laminectomy (LSPSL), and minimally invasive tubular decompression (MTD), would be included after screening based on the inclusion and exclusion criteria. The primary outcome was Oswestry Disability Index (ODI). Twenty eligible RCTs were included, with a total of 2201 patients enrolled. The NMA showed that the following surgical procedures ranked first (surface under the cumulative ranking) when compared with CL and DF: DILS for ODI (SUCRA 87.8%); LSPSL for back pain (95%); and MTD for leg pain (95.6%). MTD ranked among the top three surgical procedures for most outcomes. The quality of the synthesized evidence was low according to the Grading of Recommendations Assessment, Development, and Evaluation criteria. DILS, LSPSL, MTD, IPDs, and ED are the most effective procedures for patients with single‐segment LSS. Because of combining efficacy and safety, MTD may be the most promising routine surgical option for treating single‐segment LSS.

Thermal Dynamics of a Novel Radio-Frequency Device for Endoscopic Spine Surgery: An Experimental Model

STUDY DESIGN

Experimental study.

OBJECTIVE

In this study, the ambient temperature of a radiofrequency (RF) electrode tip was compared and analyzed in terms of products, mode, flow quantity, and flow rate.

SUMMARY OF BACKGROUND DATA

Endoscopic spine surgery is a widely used operation for degenerative lumbar stenosis and herniated lumbar disc. To perform endoscopic spine surgery, dedicated instruments like a RF generator and electrode are essential.

METHODS

An evaluation system capable of measuring temperature under equal conditions at a certain distance from the electrode tip was manufactured. The distance between the electrode tip and the temperature sensor was set to 1, 5, and 10 mm. The flow quantities of 0, 50, 100, and 150 mL/min and the flow rates of 0, 0.20, 0.53, and 0.80 m/s were compared and statistically analyzed.

RESULTS

The temperatures measured in the experiments conducted on the four combinations of RF device showed similar values, and showed differences according to the characteristics of each mode of the RF. As the distance between the electrode tip and the temperature sensor increased, the temperature decreased, and as flow quantity or flow rate increased, the temperature decreased. The maximum temperatures differed significantly according to flow quantity, between flow quantities of 0 and 100 mL/min (P  = 0.03) and between 0 and 150 mL/min (P ≤ 0.01). The maximum temperatures also differed significantly between the flow rate of 0 m/s, and the flow rates of 0.20, 0.53, and 0.80 m/s, with P ≤ 0.01 in all three comparisons.

CONCLUSION

This is the first study in which we made a customized RF temperature evaluation system and verified the temperature changes in various environments. When irrigation was performed, we could confirm that the maximum temperature was less than 60°C. Irrigation is considered essential in endoscopic spine surgery.

LEVEL OF EVIDENCE

3.

Mini-invasive bilateral transfacet screw fixation with reconstruction of the neural arch for lumbar stenosis: A two centre case series

BACKGROUND AND PURPOSE

Lumbar stenosis and instability frequently coexist. Spinal canal decompression is often combined with fixation of the relevant vertebral segment and can be performed using different techniques and devices, including pedicle screws and interspinous devices and facet screws. The present study evaluates the clinical outcome of laminectomy and single-level fusion using a minimally invasive technique for rigid posterior spinal column fixation with two cross-linked lag screws.

METHODS

The records of patients operated from 2012 to 2016 were retrieved from the computerised medical record database system. Data on age, sex, surgical level, type of deficit and disease were collected. The Oswestry Disability Index (ODI) and Short Form-36 (SF-36) questionnaires were administered pre-operatively and at 1, 6, 12 and 24 months after surgery.

MAIN FINDINGS

A total of 46 consecutive patients were operated between January 2012 to October 2016. One intraoperative complication was reported, and 4 patients experienced radiographic pseudarthrosis postoperatively. Five patients underwent additional surgery. The lumbar and lower limb VAS score, ODI and SF-36 scores showed statistically significant improvement for each score at the first and last follow-up (p < 0.01).

CONCLUSION

Percutaneous lumbar transfacet screw placement with the Facet-Link ® system is feasible and safe but with a relatively high rate of poor articular fusion. This technique can reduce the morbidity of single-level lumbar spinal stenosis and mild instability and improve patient outcome scores. Comparative studies, including randomised controlled trials, are needed to confirm these findings.

Modified Taylor Retractor in Unilateral Subperiosteal Lumbar Microdiscectomy: A Frugal Alternative to the Tubular Retractor

OBJECTIVE

To do a comparative surgical outcome and cost-benefit analysis of our simple modified Taylor retractor with both open and tubular techniques in lumbar discectomy.

METHODS

We retrospectively divided 52 lumbar disc patients operated by 2 different techniques between January 2019 and June 2020 into 2 groups- group 1 (n = 20): standard open macrodiscectomy (4-5 cm incision); group 2 (n = 32): unilateral translaminar microdiscectomy using our modified Taylor retractor with a small incision (18-20 mm, comparable to the tubular retractor). We compared both groups in terms of surgical outcomes and cost-benefit analysis. In addition, a cost-benefit comparison between our modified Taylor technique and that of the already published tubular microdiscectomy cohort was done.

RESULTS

Complete symptom resolution occurred in 85% group 1 and 84.4% group 2 patients, with no difference in complication rates. Mean hospital stay was significantly less in group 2 (1.2 ± 0.37 days) as compared with group 1 (2.4 ± 1.15, P < 0.001). The mean total cost per patient was $2253.17 ± 69.16 in the modified Taylor microdiscectomy group compared with $2495.76 ± 214.85 (P < 0.001) in standard macrodiscectomy. Compared with the previously published tubular microdiscectomy cohort ($3069.91 ± 69.16), the modified Taylor retractor was $816.74 cheaper per patient with similar length of incision, surgical outcome, and hospital stay.

CONCLUSIONS

Similar clinical outcomes at decreased costs are obtained using the modified Taylor retractor compared with the tubular retractor. The modified Taylor retractor has a simple design, is user-friendly, and frugal alternative to the tubular retractor system for microscopic discectomy, especially in the resource-constrained countries.

Minimally invasive posterior pedicle screw fixation versus open instrumentation in patients with thoracolumbar spondylodiscitis

BACKGROUND

Due to the aging society, the incidence of pyogenic spondylodiscitis is still rising. Although surgical treatment for spondylodiscitis in general is increasingly accepted, an optimal surgical strategy for treatment of pyogenic spinal infection has not yet been established. The aim of this study was to investigate the suitability of percutaneous posterior pedicle screw fixation for surgical treatment in patients with spondylodiscitis of the thoracolumbar spine.

METHODS

We conducted a retrospective review of a consecutive cohort of patients undergoing surgical treatment for spondylodiscitis of the thoracolumbar spine between January 2017 and December 2019. We assessed intraoperative and clinical data, comparing for the classic open and the percutaneous approach. In total, we analyzed 125 cases (39 female, 86 male). The mean age was 69.49 years ± 12.63 years.

RESULTS

Forty-seven (37.6%) patients were operated on by a percutaneous approach for pedicle screw fixation, and 78 (62.4%) received open surgery. There was no significant difference in the mean age of patients between both groups (p= 0.57). The time of surgery for percutaneous fixation was statistically significantly shorter (p= 0.03). Furthermore, the estimated intraoperative blood loss was significantly lower in the minimally invasive group (p < 0.001). No significant difference could be observed regarding the recurrence rate of spondylodiscitis and the occurrence of surgical site infections (p= 0.2 and 0.5, respectively).

CONCLUSION

Percutaneous posterior pedicle screw fixation appears to be a feasible option for the surgical treatment of a selected patient group with spondylodiscitis of the thoracic and lumbar spine.

Safety and Efficacy of All-In-One Percutaneous Pedicle Screw System

STUDY DESIGN

Retrospective study of the prospectively collected outcomes data.

OBJECTIVE

The indications for PPS placement during minimally invasive spine stabilization (MISt) procedures have increased in recent years. To the best of our knowledge, no studies have documented the outcomes of PPS insertion using the all-in-one PPS system. This study compared the conventional methods and the use of all-in-one percutaneous pedicle screw (PPS) system with respect to the speed and accuracy of PPS placement. We also determined the advantages associated with the use of the all-in-one PPS system.

METHODS

We evaluated 54 patients who underwent PPS insertion using the conventional method and the all-in-one PPS system during MISt procedures. We also assessed the number of implanted PPSs, the time taken to implant PPSs, and the accuracy of PPS placement based on postoperative computed tomography images.

RESULTS

A total of 254 PPSs were inserted (126 using the conventional method and 128 using the all-in-one PPS system). The PPS insertion time with the all-in-one PPS system (mean, 25.3 ± 9.1 s) was significantly shorter than that using the conventional method (mean, 63.1 ± 13.0 s; P < 0.01). With respect to the accuracy of PPS insertion, ≥ 2 mm pedicle breach was noted in one case each in both groups.

CONCLUSIONS

PPS placement using the all-in-one PPS system is as safe as conventional methods and has the potential to save the surgical time of MISt procedures.

Comparison of Minimal Invasive Versus Biportal Endoscopic Transforaminal Lumbar Interbody Fusion for Single-level Lumbar Disease

STUDY DESIGN

Retrospective study.

OBJECTIVE

The authors aimed to compare the clinical outcomes of biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) with those of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) using a microscope.

SUMMARY OF BACKGROUND DATA

Lumbar spinal fusion has been widely performed for various lumbar spinal pathologies. Minimally invasive transforaminal interbody fusion using a tubular retractor under a microscope is a method of achieving fusion while reducing soft tissue injury. Recently, several studies have reported minimally invasive techniques for lumbar discectomy, decompression, and interbody fusion using biportal endoscopic spinal surgery.

MATERIALS AND METHODS

This retrospective study included 87 patients who underwent single-level TLIF for degenerative or isthmic spondylolisthesis between 2015 and 2018. Thirty-two and 55 patients underwent BE-TLIF (group A) and MI-TLIF (group B), respectively. Visual Analogue Scale scores of the back and leg and Oswestry Disability Index were collected perioperatively.Further, data regarding perioperative complications, including length of hospital stay, time to ambulation, and fusion rate, were collected.

RESULTS

The Visual Analogue Scale score at 2 weeks and 2 months postoperatively was significantly lower in group A (P=0.001). All other clinical scores showed improvement with no significant difference between the 2 groups (P>0.05). The difference in the fusion rates between group A (93.7%) and group B (92.7%) were not significant (P=0.43).

CONCLUSIONS

Because BE-TLIF yieldeds lesser early postoperative back pain than did MI-TLIF, it may allow early ambulation and a shorter hospitalization period. BE-TLIF may be a viable alternative to MI-TLIF in patients with degenerative or isthmic spondylolisthesis with superior clinical results in the early postoperative period.

Preliminary investigation of spinal level and postural effects on thoracic muscle morphology with upright open MRI

OBJECTIVE

Spinal-muscle morphological differences between weight-bearing and supine postures have potential diagnostic, prognostic, and therapeutic applications. While the focus to date has been on cervical and lumbar regions, recent findings have associated spinal deformity with smaller paraspinal musculature in the thoracic region. We aim to quantitatively investigate the morphology of trapezius (TZ), erector spinae (ES) and transversospinalis (TS) muscles in upright postures with open upright MRI and also determine the effect of level and posture on the morphological measures.

METHODS

Six healthy volunteers (age 26 ± 6 years) were imaged (0.5 T MROpen, Paramed, Genoa, Italy) in four postures (supine, standing, standing with 30° flexion, and sitting). Two regions of the thorax, middle (T4-T5), and lower (T8-T9), were scanned separately for each posture. 2D muscle parameters such as cross-sectional area (CSA) and position (radius and angle) with respect to the vertebral body centroid were measured for the three muscles. Effect of spinal level and posture on muscle parameters was examined using 2-way repeated measures ANOVA separately for T4-T5 and T8-T9 regions.

RESULTS

The TZ CSA was smaller (40%, P = .0027) at T9 than at T8. The ES CSA was larger at T5 than at T4 (12%, P = .0048) and at T9 than at T8 (10%, P = .0018). TS CSA showed opposite trends at the two spinal regions with it being smaller (16%, P = .0047) at T5 than at T4 and larger (11%, P = .0009) at T9 than at T8. At T4-T5, the TZ CSA increased (up to 23%), and the ES and TS CSA decreased (up to 10%) in upright postures compared to supine.

CONCLUSION

Geometrical parameters that describe muscle morphology in the thorax change with level and posture. The increase in TZ CSA in upright postures could result from greater activation while upright. The decrease in ES CSA in flexed positions likely represents passive stretching compared to neutral posture.

Research Progress on the Mechanism of Lumbarmultifidus Injury and Degeneration

This review summarizes recent research progress in the clinical features, image manifestations, and pathological mechanism of multifidus injury. After a brief introduction to the fiber classification, innervation, blood supply, and multifidus function, some factors of multifidus injury, consisting of denervation, intraoperative incision selection and traction, and lumbar degenerative disease are overviewed. In addition, the clinical index of multifidus injury including myoglobin, creatine kinase, IL-6, C-reactive protein, the cross-sectional area of multifidus, the degree of fat infiltration, and intraoperative biopsy are summarized. Furthermore, we recommend that patients with chronic low back pain should take the long-term exercise of lumbodorsal muscles. Finally, some remaining issues, including external fixation and the imaging quantitative evaluation criteria of multifidus, need to be further explored in the future.

Impact of Obesity on Complication Rates, Clinical Outcomes, and Quality of Life after Minimally Invasive Transforaminal Lumbar Interbody Fusion

BACKGROUND

 Percutaneous pedicle screw fixation in obese patients remains a surgical challenge. We aimed to compare patient-reported outcomes and complication rates between obese and nonobese patients who were treated by minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

METHODS

 The authors retrospectively reviewed patients who underwent MIS-TLIF at a single institution between 2011 and 2014. Patients were classified as obese (body mass index [BMI] ≥30 kg/m²) or nonobese (BMI < 30 kg/m²), according to their BMI. Outcomes assessed were complications, numerical rating scale (NRS) scores for back and leg pain, Oswestry Disability Index (ODI), and 36-Item Short-Form Survey (SF-36) scores.

RESULTS

 The final study group consisted of 71 patients, 24 obese (33.8%, 34.8 ± 3.8 kg/m²) and 47 nonobese (66.2%, 25.4 ± 2.9 kg/m²). Instrumentation failures (13.6 vs. 17.0%), dural tears (17.2 vs. 4.0%), and revision rates (16.7 vs. 19.1%) were similar between both groups (p > 0.05). Perioperative improvements in back pain (4.3 vs. 5.4, p = 0.07), leg pain (3.8 vs. 4.2, p = 0.6), and ODI (13.3 vs. 22.5, p = 0.5) were comparable among the groups and persisted at long-term follow-up. Obese patients had worse postoperative physical component SF-36 scores than nonobese patients (36.4 vs. 42.7, p = 0.03), while the mental component scores were not statistically different (p = 0.09).

CONCLUSION

 Obese patients can achieve similar improvement of the pain intensity and functional status even at long-term follow-up. In patients with appropriate surgical indications, obesity should not be considered a contraindication for MIS-TLIF surgery.

Learning Curve and Clinical Outcome of Biportal Endoscopic-Assisted Lumbar Interbody Fusion

Interbody fusion is a common surgical technique for diseases of the lumbar spine. Biportal endoscopic-assisted lumbar interbody fusion (BE-LIF) is a novel minimally invasive technique that has a long learning curve, which can be a barrier for surgeons. Therefore, we analyzed the learning curve in terms of operative time and evaluated the outcomes of BE-LIF. A retrospective study of fifty-seven consecutive patients who underwent BE-LIF for degenerative lumbar disease by a single surgeon from January 2017 to December 2018 was performed. Fifty patients underwent a single-level procedure, and 7 underwent surgery at two levels. The mean follow-up period was 24 months (range, 14-38). Total operative time, postoperative drainage volume, time to ambulation, and complications were analyzed. Clinical outcome was measured using the Oswestry Disability Index (ODI), Visual Analog Scale (VAS) score for back and leg pain, and modified Macnab criteria. The learning curve was evaluated by a nonparametric regression locally weighted scatterplot smoothing curve. Cases before the stable point on the curve were designated as group A, and those after the stable point were designated group B. Operative time decreased as the number of cases increased. A stable point was noticed on the 400th day and the 34th case after the first BE-LIF was performed. All cases showed improved ODI and VAS scores at the final follow-up. Overall mean operative time was 171.74 ± 35.1 min. Mean operative time was significantly lower in group B (139.7 ± 11.6 min) compared to group A (193.4 ± 28.3 min). Time to ambulation was significantly lower in group B compared to group A. VAS and ODI scores did not differ between the two groups. BE-LIF is an effective minimally invasive technique for lumbar degenerative disease. In our case series, this technique required approximately 34 cases to reach an adequate performance level.

Comparison of paraspinal muscle degeneration and decompression effect between conventional open and minimal invasive approaches for posterior lumbar spine surgery

Laminotomy and transforaminal lumbar interbody fusion (TLIF) is usually used to treat unstable spinal stenosis. Minimally invasive surgery (MIS) can cause less muscle injury than conventional open surgery (COS). The purpose of this study was to compare the degree of postoperative fatty degeneration in the paraspinal muscles and the spinal decompression between COS and MIS based on MRI. Forty-six patients received laminotomy and TLIF (21 COS, 25 MIS) from February 2016 to January 2017 were included in this study. Lumbar MRI was performed within 3 months before surgery and 1 year after surgery to compare muscle-fat-index (MFI) change of the paraspinal muscles and the dural sac cross-sectional area (DSCAS) change. The average MFI change at L2–S1 erector spinae muscle was significantly greater in the COS group (27.37 ± 21.37% vs. 14.13 ± 19.19%, P = 0.044). A significant MFI change difference between the COS and MIS group was also found in the erector spinae muscle at the caudal adjacent level (54.47 ± 37.95% vs. 23.60 ± 31.59%, P = 0.016). DSCSA improvement was significantly greater in the COS group (128.15 ± 39.83 mm² vs. 78.15 ± 38.5 mm², P = 0.0005). COS is associated with more prominent fatty degeneration of the paraspinal muscles. Statically significant post-operative MFI change was only noted in erector spinae muscle at caudal adjacent level and L2–S1 mean global level. COS produces a greater area of decompression on follow up MRI than MIS with no statistical significance on clinical grounds.

Change in the dimensions of the lumbar area muscles after surgery: MRI analysis

OBJECTIVE:

This study aims to assess the change in the dimensions of the lumbar muscles in patients with chronic lower back pain using Magnetic Resonance Imaging (MRI) and to determine pre/post effects of surgery.

METHODS:

We enrolled 28 individuals (13F/15M; age: 45.39±11.56 years) whose L2–S1 muscle measurements were obtained using MRI, before and at follow-up 6–12 months after surgery. The control group comprising 37 individuals (18F/19M; age: 34.41±10.72 years) who had no lumbar pathology but for whom retrospective archive images were available. In the axial MRI analysis, the cross-sections of m.multifidus, mm.erector spinae and m.psoas major on both sides were measured with the ‘closed polygon’ technique.

RESULTS:

The L2–3 and L4–5 levels of the m.multifidus on the right side, the L2–3, L4–5 and L5–S1 levels of the m.multifidus and the L5–S1 levels of the mm. erector spinae on the left side cross-sectional areas were significantly lower than the control group (p<0.05). The right-side m.multifidus and the left-side mm.erector spinae sectional areas were significantly lower than the pre-surgery values at the L5–S1 levels (p<0.05).

CONCLUSION:

This study demonstrated that chronic lower back pain causes atrophy in the lumbar muscles and established the existence and continuity of atrophy after surgery.

From clinic to hypothesis, an innovative operation for the treatment of lumbar spinal stenosis in a minimal invasive way

Concerning the damage to back muscles and posterior ligament complex (PLC) by posterior open approach for lumbar spinal stenosis (LSS), the oblique lateral intervertebral fusion (OLIF) is pretty popular nowadays. However, oblique lateral approach has obvious drawbacks, which are limited vision and operative scope for achieving spinal canal decompression. Herein, we present a hypothesis that lumbar canal decompression can be well achieved by OLIF combined with spinal endoscope operative system. Nerval decompression and spinal reconstruction are achieved in a minimal invasive way, which may play an instructive role for the treatment of serious LSS.

Unilateral biportal endoscopic decompression for degenerative lumbar canal stenosis

Background

Unilateral biportal endoscopic (UBE) decompression is a minimally invasive (MI) approach to treat degenerative lumbar canal stenosis (DLCS). Decompression can be performed in a clear and magnified surgical field with proper control of normal saline inflow and outflow.

Methods

Clinical and radiographic data of 81 consecutive patients of DLCS treated between July 2018 and Feb 2019 using UBE techniques were reviewed. They were 38 males and 43 females with an average age of 70.2. Sixty-nine had pure canal stenosis and 12 patients had associated spondylolisthesis. Bilateral decompression via unilateral laminotomy was performed from the side on patients with more severe neurological symptoms. This is a retrospective study from chart review and image analysis. Therefore, we don't have formal ethical information for this study, and it is not mandatory in our hospital.

Results

At the final follow-up, the mean VAS for low back pain was improved from 4.3±3.0 to 1.2±1.0 and the VAS for leg symptoms was improved from 7.3±2.2 to 0.9±0.7. The mean JOA score and ODI was significantly improved from 13.3±7.9 to 25.3±5.0 and from 54.6±16.9 to 14.6±12.6, respectively. Modified Macnab criteria were excellent in 47 patients (58.0%), good in 29 (35.8%), fair in 5 (6.2%). The average hospital stay was 3.6±2.4 days. MRI before and after the operation showed the cross-sectional dural area (CSDA) was significantly increased from 71.4±36.5 to 177.3±59.2 mm², corresponding to a 201.9%±188.0% increase. The percentage of facet joint preservation was 84.2% on the approach side and 92.9% on the contralateral side. Complications included 4 dural tears, 1 transient motor weakness, 1 inadequate decompression, and 1 epidural hematoma.

Conclusions

With UBE techniques, decompression for DLCS can be performed safely and effectively. The soft tissue and facet joint destruction are minimized; therefore, it is possible to avoid spinal fusion as well as to preserve the segmental stability.

Two window-minimally invasive lumbar spine surgery (new approach) has a better post operative outcome and less soft tissue damage

Introduction

The purpose of this new approach is to develop a method that is less invasive as well as less traumatic and can provide a better exposure/view of the surgical field. Postoperatively, the patient has less pain, short hospital stay and less use of the postoperative pain control medications. As compared to other minimally invasive spine surgeries this approach results in less soft tissue damage, minimal muscle destruction, less retraction and better surgical outcome.

Methods

In this article authors focus on the new approach that has cost effective benefits as well as short recovery time postoperatively.

Results

Approach is applicable for severe spinal stenosis as compared to other Minimally Invasive Spine Surgery (MISS) techniques that are only applicable for the mild to moderate stenosis or degenerative processes. This plane is avascular plane so no or less bleeding is anticipated from this procedure.

Conclusion

The technique facilitates bilateral canal enlargement through unilateral approach and provides accessibility to the contralateral foramen for decompression with perfect exposure and allows instrumentation through the lateral window with no muscle destruction.

•

Minimally Invasive Spine Surgery, Fusion, Two windows approach.

Percutaneous CT-guided lumbar trans-facet pedicle screw fixation in lumbar microinstability syndrome: feasibility of a novel approach

STUDY DESIGN

Prospective experimental uncontrolled trial.

BACKGROUND

Lumbar microinstability (MI) is a common cause of lower back pain (LBP) and is related to intervertebral disc degeneration that leads to inability to adequately absorb applied loads. The term "microinstability" has recently been introduced to denote a specific syndrome of biomechanical dysfunction with minimal anatomical change. Trans-facet fixation (TFF) is a minimally invasive technique that involves the placement of screws across the facet joint and into the pedicle, to attain improved stability in the spine.

PURPOSE

In this study, we aimed to evaluate the effectiveness, in terms of pain and disability reduction, of a stand-alone TFF in treatment of patients with chronic low back pain (LBP) due to MI. Moreover, as a secondary endpoint, the purpose was to assess the feasibility and safety of a novel percutaneous CT-guided technique.

METHODS

We performed percutaneous CT-guided TFF in 84 consecutive patients presenting with chronic LBP attributable to MI at a single lumbar level without spondylolysis. Pre- and post-procedure pain and disability levels were measured using the visual analogue scale (VAS) and Oswestry Disability Index (ODI).

RESULTS

At 2 years, TFF resulted in significant reductions in both VAS and ODI scores. CT-guided procedures were tolerated well by all patients under light sedation with a mean procedural time of 45 min, and there were no reported immediate or delayed procedural complications.

CONCLUSION

TFF seems to be a powerful technique for lumbar spine stabilization in patients with chronic mechanical LBP related to lumbar MI. CT-guided technique is fast, precise, and safe and can be performed in simple analgo-sedation.

Soft Tissue: A Possible Source of Pain Pre and Post Minimally Invasive Spine Surgery

STUDY DESIGN

Case studies.

OBJECTIVES

To demonstrate that muscle generated pain (MGP) may be a cause of pain in patients who have undergone minimally invasive spine surgery (MISS).

METHODS

A physical examination including electrical stimulation of putative pain generating muscles to identify the presence of lowered thresholds for depolarization of muscle nociceptors, and an examination of strength and flexibility of key muscles in the upper and lower body, may identify multiple etiologies of MGP. Treatment of identified muscles consisted of muscle/tendon injections to identified sensitized muscles followed by exercises incorporating relaxation limbering and stretching.

RESULTS

Postsurgical pain was eliminated and mobility restored in both presented cases replicating success in prior published studies.

CONCLUSIONS

Understanding the pathophysiological mechanisms of muscle pain may facilitate the evaluation and treatment of MGP in MISS patients diagnosed with failed back surgery syndrome.

Quantitative analysis of paraspinal muscle atrophy after oblique lateral interbody fusion alone vs. combined with percutaneous pedicle screw fixation in patients with spondylolisthesis

BACKGROUND

There is no available literature for comparison on muscle atrophy between the "stand-alone" oblique lateral interbody fusion (OLIF) and regular OLIF (i.e., combined with percutaneous pedicle screws fixation (PPSF) in patients with spondylolisthesis). This study aimed to identify changes in back muscle atrophy between the two surgeries.

METHODS

This was a retrospective cohort study of patients who underwent OLIF or OLIF+PPSF at Beijing Jishuitan Hospital and Shanghai ChangZheng Hospital between 07/2014 and 10/2017. Computed tomography (CT) was used to measure functional cross-sectional area (FCSA) and fat infiltration percentage (FIP) of the multifidus and erector spinae before and 24 months after surgery.

RESULT

There were no differences in FCSA and FIP between OLIF (n = 32) and OLIF+PPSF (n = 41) groups before surgery. In the OLIF group, the multifidus and erector spinae FCSA and FIP did not change at 24 months (FCSA: multifidus: from 8.59 ± 1.76 to 9.39 ± 1.74 cm2, P = 0.072; erector spinae: from 13.32 ± 1.59 to 13.55 ± 1.31 cm2, P = 0.533) (FIP: multifidus: from 15.91 ± 5.30% to 14.38 ± 3.21%, P = 0.721; erector spinae: from 11.63 ± 3.05% to 11.22 ± 3.12%, P = 0.578). In the OLIF+PPSF group, the multifidus and erector spinae FCSA decreased (multifidus: from 7.72 ± 2.69 to 5.67 ± 1.71 cm2, P < 0.001; erector spinae: from 12.60 ± 2.04 to 10.15 ± 1.82 cm2, P < 0.001), while the FIP increased (multifidus: from 16.13 ± 7.01% to 49.38 ± 20.54%, P < 0.001; erector spinae: from 11.93 ± 3.22% to 22.60 ± 4.99%, P < 0.001). The differences of FCSA and FIP between the two groups at 24 months were significant (all P < 0.001). The patients in the standalone OLIF group had better VAS back pain, and JOA scores than the patients in the OLIF combined group (all P < 0.05) at 1 week and 3 months after surgery. There were two cases (4.9%) of adjacent segment degeneration in the OLIF combined group, while there was no case in the OLIF alone group.

CONCLUSIONS

Standalone OLIF had better clinical outcomes at 1 week and 3 months than OLIF+PPSF in patients with spondylolisthesis. OLIF may not result in paraspinal muscle atrophy at 24 months after surgery.

Reattachment of the Multifidus Tendon in Lumbar Surgery to Decrease Postoperative Back Pain: A Technical Note

The posterior midline approach to the lumbar spine requires significant manipulation of the paraspinal muscles. Muscle detachment and retraction results in iatrogenic damage such as crush injury, devascularization, and denervation, all of which have been associated with postoperative pain. The muscle most directly affected by the posterior approach is the lumbar multifidus (LM), the largest and most medial of the deep lumbar paraspinal muscles. The effects of the posterior approach on the integrity of the LM is concerning, as multiple studies have demonstrated that intraoperative injuries sustained by the LM lead to postoperative muscle atrophy and potentially worsening low back pain. Given the inevitability of intraoperative paraspinal muscle manipulation when using the posterior approach, this technical note describes methods by which surgeons may minimize LM tissue disruption and restore the anatomical position of the LM to ultimately expedite recovery, minimize postoperative pain, and improve patient satisfaction.

An updated meta-analysis of clinical outcomes comparing minimally invasive with open transforaminal lumbar interbody fusion in patients with degenerative lumbar diseases

BACKGROUND & AIMS

Open-transforaminal lumbar interbody fusion (O-TLIF) is regarded as the standard (S) approach which is currently available for patients with degenerative lumbar diseases patients. In addition, minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has proposed and gradually obtained popularity compared with O-TLIF procedures due to its beneficial outcomes in minimized tissue injury and quicker recovery. Nonetheless, debates exist concerning the use of MI-TLIF with its conflicting outcomes of clinical effect and safety in several publications. The purpose of the current study is to conduct an updated meta-analysis to provide eligible and systematical assessment available for the evaluation of the efficacy and safety of MI-TLIF in comparison with O-TLIF.

METHODS

Publications on the comparison of O-TLIF and MI-TLIF in treating degenerative lumbar diseases in last 5 years were collected. After rigorous reviewing on the eligibility of publications, the available data was further extracted from qualified trials. All trials were conducted with the analysis of the summary hazard ratios (HRs) of the interest endpoints, including intraoperative and postoperative outcomes.

RESULTS

Admittedly, it is hard to run a clinical RCT to compare the prognosis of patients undergoing O-TLIF and MI-TLIF. A total of 10 trials including non-randomized trials in the current study were collected according to our inclusion criteria. The pooled results of surgery duration indicated that MI-TLIF was highly associated with shorter length of hospital stay, less blood loss, and less complications. However, there were no remarkable differences in the operate time, VAS-BP, VAS-LP, and ODI between the 2 study groups.

CONCLUSION

The quantitative analysis and combined results of our study suggest that MI-TLIF may be a valid and alternative method with safe profile in comparison of O-TLIF, with reduced blood loss, decreased length of stay, and complication rates. While, no remarkable differences were found or observed in the operate time, VAS-BP, VAS-LP, and ODI. Considering the limited available data and sample size, more RCTs with high quality are demanded to confirm the role of MI-TLIF as a standard approach in treating degenerative lumbar diseases.

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF): A review of indications, technique, results and complications

Minimal access surgery has revolutionized most surgical disciplines and spine surgery is no exception. Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) was devised to reduce the approach-related morbidity of open TLIF and has flourished in the last decade. With expanding indications, standardization of technique and equipment, publication of more studies on its results and complications being brought to light - an update of the existing knowledge on MI-TLIF is imminent. We provide a review of the indications, technique, results and complications of MI-TLIF while also highlighting its variations and utility in special situations.

[Postoperative management of weight bearing and rehabilitation after lumbar spinal surgery]

BACKGROUND

Because of the growing trend of lumbar spinal surgery, it is essential for physicians and physiotherapists to develop standardized postoperative treatment. However, currently postoperative treatment after lumbar spinal surgery is controversial.

PURPOSE OF THE STUDY

The purpose of this review article is to make recommendations for the postoperative treatment of lumbar intervertebral disc surgery, lumbar decompression surgery and lumbar spinal fusion surgery regarding mobilization, weight bearing and rehabilitation. These recommendations are based on current evidence and experience in our institution.

MATERIALS AND METHODS

A selective literature research of relevant publications was conducted in Pubmed. The studies are presented in tabular form.

RESULTS

Patient training, accurate information about the postoperative course, information about limitations and stress possibilities as well as pain management seem to have an important role in the final outcome of the operation. Ideally, these procedures should be performed preoperatively or at the latest or repeatedly from the first postoperative day after lumbar spine surgery. Physiotherapy can have a positive impact on the clinical and functional outcome after lumbar disc, decompression and fusion surgery.

DISCUSSION

Due to the heterogeneity of the intensity, duration and form of physiotherapy or rehabilitation, which are listed as interventions in the various studies, it is only possible to draw limited conclusions about general instructions for action on "physiotherapy" after spinal surgery.

Comparison of bilateral decompression via unilateral laminotomy and conventional laminectomy for single-level degenerative lumbar spinal stenosis regarding low back pain, functional outcome, and quality of life - A Randomized Controlled, Prospective Trial

Background

Conventional posterior open lumbar surgery is associated with considerable trauma to the paraspinal muscles. Severe damage to the paraspinal muscles could cause low back pain (LBP), resulting in poor functional outcomes. Thus, several studies have proposed numerous surgical techniques that can minimize damage to the paraspinal muscles, particularly unilateral laminotomy for bilateral decompression. The purpose of this study is to compare the degree of postoperative LBP, functional outcome, and quality of life of patients between bilateral decompression via unilateral laminotomy (BDUL; group U) and conventional laminectomy (CL; group C).

Methods

Of 87 patients who underwent diagnostic and decompression surgery, 50 patients who met the inclusion and exclusion criteria and were followed up for > 2 years were enrolled. The patients were asked to record their visual analog scale pain score after 6, 12, and 24 months postoperatively. BDUL was used for group U, whereas CL was used for group C. The patients were randomly divided based on one of the two techniques, and they were followed up for over 2 years. Functional outcomes were assessed by the Oswestry Disability Index (ODI), Roland–Morris Disability Questionnaire (RMDQ), and SF-36.

Results

Operation time was significantly shorter in group U than in group C (p = 0.003). At 6, 12, and 24 months, there was no significant difference between the two groups in terms of spine-related pain (all p > 0.05). Functional outcomes using ODI and RMDQ and quality of life using SF-36 were not significantly different between the groups (all p > 0.05).

Conclusions

Regarding single-level decompression for degenerative lumbar spinal stenosis, group U had the advantages of shorter operation time than group C, but not in terms of back pain, functional outcome, and quality of life.

Learning Curve for Robot-Assisted Percutaneous Pedicle Screw Placement in Thoracolumbar Surgery

Study Design

Retrospective review of an initial cohort of consecutive patients undergoing robot-assisted pedicle screw placement.

Purpose

We aimed to evaluate the learning curve, if any, of this new technology over the course of our experience.

Overview of Literature

Percutaneous pedicle screws have specific advantages over open freehand screws. However, they require intraoperative imaging for their placement (e.g., fluoroscopy and navigation) and require increased surgeon training and skill with the learning curve estimated at approximately 20–30 cases. To our knowledge, this is the first study that measures the learning curve of robot-guided purely percutaneous pedicle screw placement with comprehensive objective postoperative computed tomography (CT) scoring, time per screw placement, and fluoroscopy time.

Methods

We included the first 80 consecutive patients undergoing robot-assisted spinal surgery at Melbourne Private Hospital. Data were collected for pedicle screw placement accuracy, placement time, fluoroscopy time, and revision rate. Patient demographic and relevant perioperative and procedural data were also collected. The patients were divided equally into four sub-groups as per their chronological date of surgery to evaluate how the learning curve affected screw placement outcomes.

Results

Total 80 patients were included; 73 (91%) had complete data and postoperative CT imaging that could help assess that placement of 352 thoracolumbar pedicle screws. The rate of clinically acceptable screw placement was high (96.6%, 95.4%, 95.6%, and 90.7%, in groups 1 to 4, respectively, p=0.314) over time. The median time per screw was 7.0 minutes (6.5, 7.0, 6.0, and 6.0 minutes in groups 1 to 4, respectively, p=0.605). Intraoperative revision occurred in only 1 of the 352 screws (0.3%).

Conclusions

We found that robot-assisted screw placement had high accuracy, low placement time, low fluoroscopy time, and a low complication rate. However, there were no significant differences in these parameters at the initial experience and the practiced, experience placement (after approximately 1 year), indicating that robot-assisted pedicle screw placement has a very short (almost no) learning curve.

The use of robotics in minimally invasive spine surgery

The field of spine surgery has changed significantly over the past few decades as once technological fantasy has become reality. The advent of stereotaxis, intra-operative navigation, endoscopy, and percutaneous instrumentation have altered the landscape of spine surgery. The concept of minimally invasive spine (MIS) surgery has blossomed over the past ten years and now robot-assisted spine surgery is being championed by some as another potential paradigm altering technological advancement. The application of robotics in other surgical specialties has been shown to be a safe and feasible alternative to the traditional, open approach. In 2004 the Mazor Spine Assist robot was approved by FDA to assist with placement of pedicle screws and since then, more advanced robots with promising clinical outcomes have been introduced. Currently, robotic platforms are limited to pedicle screw placement. However, there are centers investigating the role of robotics in decompression, dural closure, and pre-planned osteotomies. Robot-assisted spine surgery has been shown to increase the accuracy of pedicle screw placement and decrease radiation exposure to surgeons. However, modern robotic technology also has certain disadvantages including a high introductory cost, steep learning curve, and inherent technological glitches. Currently, robotic spine surgery is in its infancy and most of the objective evidence available regarding its benefits draws from the use of robots in a shared-control model to assist with the placement of pedicle screws. As artificial intelligence software and feedback sensor design become more sophisticated, robots could facilitate other, more complex surgical tasks such as bony decompression or dural closure. The accuracy and precision afforded by the current robots available for use in spinal surgery potentially allow for even less tissue destructive and more meticulous MIS surgery. This article aims to provide a contemporary review of the use of robotics in MIS surgery.

Comparative Analysis of Two Transforaminal Lumbar Interbody Fusion Techniques: Open TLIF Versus Wiltse MIS TLIF

STUDY DESIGN

A retrospective cohort study at a single institution.

OBJECTIVE

The aim of this study was to analyze the perioperative and postoperative outcomes of patients who underwent open transforaminal lumbar interbody fusion (O-TLIF) and bilateral minimally invasive surgery (MIS) Wiltse approach TLIF (Wil-TLIF).

SUMMARY OF BACKGROUND DATA

Several studies have compared open TLIF to MIS TLIF; however, comparing the techniques using a large cohort of one-level TLIFs has not been fully explored.

METHODS

We reviewed the charts of patients undergoing a single-level primary posterior lumbar interbody fusion between 2012 and 2017. The cases were categorized as Open TLIF (traditional midline exposure including lateral exposure of transverse processes) or bilateral paramedian Wiltse TLIF approach. Differences between groups were assessed by t tests.

RESULTS

Two hundred twenty-seven patients underwent one-level primary TLIF (116 O-TLIF, 111 Wil-TLIF). There was no difference in age, gender, American Society of Anesthesiologists (ASA), or body mass index (BMI) between groups. Wil-TLIF had the lowest estimated blood loss (EBL; 197 vs. 499 mL O-TLIF, P ≤ 0.001), length of stay (LOS; 2.7 vs. 3.6 days O-TLIF, P ≤ 0.001), overall complication rate (12% vs. 24% O-TLIF, P = 0.015), minor complication rate (7% vs. 16% O-TLIF, P = 0.049), and 90-day readmission rate (1% vs. 8% O-TLIF, P = 0.012). Wil-TLIF was associated with the higher fluoroscopy time (83 vs. 24 seconds O-TLIF, P ≤ 0.001). There was not a significant difference in operative time, intraoperative or neurological complications, extubation time, reoperation rate, or infection rate.

CONCLUSION

In comparing Wiltse MIS TLIF to Open TLIF, the minimally invasive paramedian Wiltse approach demonstrated the lowest EBL, LOS, readmission rates, and complications, but longer fluoroscopy times when compared with the traditional open approach.

LEVEL OF EVIDENCE

3.

Minimally Invasive, Stereotactic, Wireless, Percutaneous Pedicle Screw Placement in the Lumbar Spine: Accuracy Rates With 182 Consecutive Screws

BACKGROUND

Standard fluoroscopic navigation and stereotactic computed tomography-guided lumbar pedicle screw instrumentation traditionally relied on the placement of Kirshner wires (K-wires) to ensure accurate screw placement. The use of K-wires, however, is associated with a risk of morbidity due to potential ventral displacement into the retroperitoneum. We report our experience using a computer image-guided, wireless method for pedicle screw placement. We hypothesize that minimally invasive, wireless pedicle screw placement is as accurate and safe as the traditional technique using K-wires while decreasing operative time and avoiding potential complications associated with K-wires.

METHODS

We conducted a retrospective review of 42 consecutive patients who underwent a stereotactic-guided, wireless lumbar pedicle screw placement. All screws were placed to provide fixation to a variety of interbody fusion constructs including anterior lumbar interbody fusion, lateral interbody fusion, and transforaminal lumbar interbody fusion. The procedures were performed using the O-arm intraoperative imaging system with StealthStation navigation (Medtronic, Memphis, TN) and Medtronic navigated instrumentation. After placing a percutaneous navigation frame into the posterior superior iliac spine or onto an adjacent spinous process, an intraoperative O-arm image was obtained to allow subsequent StealthStation navigation. Para-median incisions were selected to allow precise percutaneous access to the target pedicles. The pedicles were cannulated using either a stereotactic drill or a novel awl-tipped tap along with a low-speed/high-torque power driver. The initial trajectory into the pedicle was recorded on the Medtronic StealthStation prior to removal of the drill or awl-tap, creating a "virtual" K-wire rather than inserting an actual K-wire to allow subsequent tapping and screw insertion. Accurate screw placement is achieved by following the virtual path as an exact computer-aided design model of the screw traversing the pedicle is projected onto the display and by using audible and tactile feedback. A second O-arm scan was obtained to confirm accuracy of screw placement.

RESULTS

A total of 20 women and 22 men (average age = 56 years) underwent a total of 182 pedicle screw placements using the stereotactic, wireless technique. The total breach rate was 9.9%, with a clinically significant breach rate of 0% (defined as >2 mm medial breach or >4 mm lateral breach) and a clinical complication rate of 0%.

CONCLUSIONS

Wireless, percutaneous placement of lumbar pedicle screws using computed tomography-guided stereotactic navigation is a safe, reproducible technique with very high accuracy rates.

Longitudinal Evaluation of the Histological Changes in a Rat Model of Paravertebral Muscle Injury

Introduction

Thus far, few reports have described the time series histological variations in injured paravertebral muscle tissues for long durations, considering the type of pain. The purpose of this study is to evaluate histological changes in injured paravertebral muscles and dominant nerves considering the type of pain.

Methods

We used 59 eight-week-old male Sprague-Dawley rats. A 115-g weight was dropped from a height of 1 m on the right paravertebral muscle. Fluoro-Gold (FG), a sensory nerve tracer, was injected into this muscle. Hematoxylin and eosin (HE) staining and nerve growth factor (NGF) immunostaining of the muscle were performed for histological evaluation. L2 dorsal root ganglia (DRG) on both sides were resected, and immunohistochemical staining was performed for calcitonin gene-related peptide (CGRP, a pain-related neuropeptide) and for activating transcription factor 3 (ATF3, a neuron injury marker). Each examination was performed at 3 days, 1-3 weeks, and 6 weeks after injury.

Results

HE staining of the paravertebral muscle indicated infiltration of inflammatory cells and the presence of granulation tissue in the injured part on the ipsilateral side at 3 days and 1 week after the injury. Fibroblasts and adipocytes were present at 2-3 weeks. At 6 weeks, the injured tissue was almost completely repaired. NGF was detected at 2-3 weeks post injury and appeared to colocalize with fibroblasts, but was not observed at 6 weeks post injury. The percentage of cells double-labeled with FG and CGRP in FG-positive cells of the primary muscle was significantly higher in the injured side at 3 days and 1-3 weeks post injury (P < 0.05). However, at 6 weeks, no significant difference was observed. No significant expression of ATF3 was observed.

Conclusions

These results suggest that sensitization of the dominant nerve in the DRG, in which NGF may play an important role, can protract pain in injured muscles.

Minimally invasive spine surgery in the pediatric and adolescent population: A case series

Background:

There is scant literature evaluating the indications, techniques, and outcomes of minimally invasive spine (MIS) surgery undertaken for pediatric and adolescent spine pathology. Our study attempts to evaluate the safe and effective use of MIS techniques in pediatric and adolescent patients and to appreciate the technical nuances of MIS surgery for this age group.

Methods:

Consecutive pediatric and adolescent patients undergoing elective MIS lumbar procedures, from 2008 to 2016, were retrospectively analyzed from the practice of a single fellowship-trained academic spinal neurosurgeon. Information was retrieved regarding procedure and disease pathology. Descriptive data was obtained including age, sex, body mass index (BMI), insurance coverage, smoking status, and co-morbidities. Outcome measures were recorded including intraoperative complications, revision surgery, and return-to-function.

Results:

Sixteen patients underwent 17 surgeries. The median BMI was 29.2 (range, 20.8–41.5). Age ranged from 12 to 19 years. Nearly 20% of the patients in our series were smokers. Most patients underwent discectomy, with L5-S1 being the most common level. One patient underwent direct pars defect repair and another underwent recurrent discectomy. More than 90% of the patients were complication-free at follow-up period of 6 months. One patient had a recurrent disc herniation and another had a superficial wound infection. Overall, 82.4% patients enjoyed full return to sports such as weight lifting, gymnastics, and contact sports. One patient required pain management to help alleviate ongoing pain. Another patient required a course of outpatient rehabilitation to help with a “foot drop.”

Conclusion:

Our series illustrates the effective application of MIS techniques among carefully selected pediatric patients. Emphasis is on using a smaller (16 mm) tubular retractor and causing minimal disruption of paraspinal osseo-tendinous structures. MIS techniques can be successfully applied to the pediatric and adolescent age group.