Iatrogenic injury to the erector spinae during posterior lumbar spine surgery: underlying anatomical considerations, preventable root causes, and surgical tips and tricks

Different Degeneration Patterns of Paraspinal Muscles Between Double-Level and Single-Level Lumbar Spondylolisthesis: An Magnetic Resonance Imaging Analysis of 140 Patients

OBJECTIVE

To evaluate the degeneration patterns of paraspinal muscles in double-level degenerative lumbar spondylolisthesis (dl-DLS) versus single-level degenerative lumbar spondylolisthesis (sl-DLS).

METHODS

A total of 67 dl-DLS and 73 sl-DLS patients were included. Multifidus (MF), erector spinae (ES), and psoas major (PM)'s fatty infiltration (FI) and relative cross-sectional area (rCSA) were measured. Sagittal parameters such as lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) were also assessed. Comparisons and correlation analysis were performed between the 2 groups.

RESULTS

MF atrophy is worse in dl-DLS patients from L3-4 to L5-S1, with higher FI from L1-2 to L5-S1 compared to sl-DLS patients. ES atrophy and FI are more pronounced in dl-DLS patients from L1-2 to L5-S1. PM atrophy is more significant in dl-DLS patients at L2-3 to L5-S1, with heavier FI from L1-2 to L3-4, though no difference in FI from L4-5 to L5-S1. The rCSA and FI of MF and ES show significant differences between adjacent segments in both groups, except for MF rCSA between L3-4 and L4-5 in dl-DLS. In dl-DLS, PM rCSA negatively correlates with PT from L4-5 to L2-3, while FI of MF and ES in L5-S1 positively correlates with LL. In sl-DLS, PM FI in L4-5 and L5-S1 negatively correlates with LL.

CONCLUSION

Degeneration of MF, ES, and PM is more severe in dl-DLS patients, particularly at the spondylolisthesis level. Severe paraspinal muscle degeneration can lead to spinal force imbalance and progression from sl-DLS to dl-DLS. The degradation of PM and ES correlates negatively with PT and SVA, indicating a link to pelvic decompensation and SVA abnormalities, potentially causing disproportionate degenerative changes in dl-DLS patients.

The impact of spinal fusion of adolescent idiopathic scoliosis in Salah (Islamic Prayer) movement: a retrospective case-control study

BACKGROUND

Corrective spine surgery is widely accepted for treating severe adolescent idiopathic scoliosis (AIS). Postoperative spinal range of motion (ROM) could be affected after such surgery. In certain populations, such as Muslims, this ROM change can impact daily life, as it may affect the five-times-a-day prayer (Salah). This study aims to assess the influence of spinal fusion (SF) in Adolescent Idiopathic Scoliosis (AIS) during the daily Islamic prayer (Salah).

METHODS

SF-AIS patients were videoed while performing Salah prayer. The kinematic documentation was assessed and compared to Salah movements of a control group of age-matched Muslim AIS patients, who had not had surgery. The prayer quality changes were subjectively classified into improved, no change/remained, and worsened, according to the Global Perceived Effect (GPE). Functional outcome and pain were assessed by the Scoliosis Research Society Questionnaire Version 30 (SRS-30).

RESULTS

Thirty-nine women and five men (mean age±SD: 14.8±2.3 years) met the inclusion criteria, and unoperated AIS patients were used as control (twenty-two women, mean age±SD: 15.32±1.43 years). The prostrations ROM of the SF-AIS group differed significantly from the control group (p<0.05). The GPE of the prayer movement showed improvement in 36.4%, no change in 59.1%, and worsening in 4.5% of the SF-AIS patients. The worsened group had a significantly lower bowing ROM and higher prostrations ROM compared to all groups of prayer quality changes (p<0.05). SRS-30 scores showed good outcomes (function 4.0±0.2, pain 4.2±0.5), along with the overall bowing ROM and prostrations ROM (84.2±12.0° and 53.4±9.6°, respectively). Moreover, a significant moderate positive correlation between the bowing ROM and pain (r=0.417, p=0.007) was also found.

CONCLUSION

Spinal fusion positively affects AIS Islamic patients in maintaining their daily Salah movement, ROM and prayer quality. Prayer quality assessment should be given extra attention as an adjuvant of the SRS-30 questionnaire to evaluate Muslim patients.

What are the differences in paraspinal muscle morphometry among degenerative spondylolisthesis patients, isthmic spondylolisthesis patients, and healthy individuals? A propensity score matching analysis

PURPOSE

To compare the morphometry of paraspinal muscles in patients with degenerative spondylolisthesis (DS), isthmic spondylolisthesis (IS), and healthy individuals.

METHODS

Thirty-seven pairs of DS patients were selected using propensity score matching with IS patients, while 37 healthy individuals matched for age, sex, and BMI were selected as controls. The relative cross-sectional area (rCSA), and relative functional cross-sectional area (rfCSA) of paraspinal muscles were measured, and the degree of fatty infiltration (FI) was calculated. Based on occupational differences, the patients were also divided into worker and farmer groups, and the same measurements were taken on them.

RESULTS

At the L3/L4 level, the multifidus (MF) FI was greater in the DS and IS groups than in the control group, the erector spinae (ES) rfCSA was higher in the IS group than in the DS and control groups. At the L4/L5 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS and control groups. At the L5/S1 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS group. At the L3/L4, L4/L5 level, MF rfCSA were higher in the worker group than in the farmer group (p < 0.05).

CONCLUSION

The morphological changes in paraspinal muscles in patients with DS were dominated by selective atrophy of the MF, while in patients with IS, the morphological changes in paraspinal muscle showed selective atrophy of the MF accompanied by compensatory hypertrophy of the ES. The surgeon should consider the morphological differences in paraspinal muscle between different types of lumbar spondylolisthesis when establishing the appropriate surgical program.

Minimally invasive technique of monoaxial percutaneous screws and instrumentational maneuvers in thoracolumbar and lumbar fractures

OBJECTIVES

Percutaneous pedicle screw fixation (PPSF) has been a common surgery for treating thoracolumbar and lumbar fractures. Many studies have reported PPSF is associated with poor reduction. We present a reliable method by using short-segment monoaxial percutaneous screws and instrumentational maneuvers to reduce the spine. This study aimed to evaluate radiological and clinical results of this method of reduction compared to traditional polyaxial screws method in treating thoracolumbar and lumbar fractures.

METHODS

From February 2015 to February 2021, 64 patients with thoracolumbar and lumbar fractures in our department were retrospectively reviewed and divided into experimental group and control group according to different treatment methods. The experimental group was treated with short-segment monoaxial percutaneous screws (which were inserted at the adjacent vertebrae one level above, one level below the fracture, and the fractured vertebra) and instrumentational maneuvers method, while the control group was treated with traditional polyaxial screws method. The operation time was recorded. Visual analogue scale (VAS) and Oswestry disability index (ODI) were assessed as the clinical outcomes. The anterior height of the injured vertebra (AVH), the kyphosis cobb angle and the vertebral wedge angle were used to evaluate the fracture radiological reduction.

RESULTS

A total of 64 patients were enrolled including 31 in the experimental group and 33 in the control group. There were no significant difference in operation time, AVH, the kyphosis cobb angle,the wedge angle of injured vertebra,VAS and ODI score between the two groups in preoperation. In each group, there were significant differences in the AVH, the kyphosis cobb angle and wedge angle of injured vertebra between preoperation and immediate postoperation. In each group, there were significant differences in VAS and ODI score between the preoperation and last follow-up. The total correction rates of AVH,the kyphosis cobb angle and the wedge angle of injured vertebra were significantly higher in the experimental group than those in the control group, while the loss of correction was significantly lower than the control.

CONCLUSIONS

The reduction technique using monoaxial percutaneous screws and instrumentational maneuvers for thoracolumbar and lumbar fractures exhibited better radiological results and satisfying functional outcomes when compared to traditional polyaxial screws.

Long-Term Outcomes After Minimally Invasive Bilateral or Unilateral Laminotomy for Degenerative Lumbar Spinal Stenosis: A Minimum 10-Year Follow-Up Study

OBJECTIVE

The optimal surgical procedure for minimal surgical intervention in symptomatic degenerative lumbar spinal stenosis (DLSS) is unknown. This article presents a method of minimally invasive decompression alone and reports the long-term outcomes and complications of patients treated with minimally invasive bilateral or unilateral laminotomy decompression performed by one surgeon.

METHODS

Patients with DLSS who underwent minimally invasive laminotomy decompression alone from March 2008 to October 2010 were included in the study, and 106 patients were followed up for at least 10 years. Clinical outcomes were assessed by Japanese Orthopedic Association, Oswestry Disability Index, and visual analog scale for back pain scores, and changes in walking tolerance and leg numbness were evaluated. Complications were recorded.

RESULTS

A total of 106 patients who met the inclusion and exclusion criteria were included in the study (mean age = 64 years, range = 43-83). The Japanese Orthopedic Association, Oswestry Disability Index, and visual analog scale back pain scores of patients significantly changed between before surgery and at subsequent follow-up (P < 0.001). The walking tolerance and leg numbness of patients significantly improved (P < 0.001), and these functions were well maintained during follow-up. Complications included intraoperative dural tears (n = 5), a wound infection (n = 1), deep vein thrombosis (n = 1), and nerve root lesions on the asymptomatic side (n = 2), all of which recovered within 3 months.

CONCLUSIONS

Minimally invasive laminotomy decompression is an effective procedure and achieves beneficial long-term clinical results for DLSS.

Different degeneration patterns of paraspinal muscles in degenerative lumbar diseases: a MRI analysis of 154 patients

STUDY DESIGN

A retrospective study.

OBJECTIVE

To evaluate the different degeneration patterns of paraspinal muscles in degenerative lumbar diseases and their correlation with lumbar spine degeneration severity. The degeneration characteristics of different paraspinal muscles in degenerative lumbar diseases remain unclear.

METHODS

78 patients diagnosed with single-level degenerative lumbar spondylolisthesis (DLS) and 76 patients with degenerative lumbar kyphosis (DLK) were included as DLS and DLK groups. Paraspinal muscle parameters of psoas major (PS), erector spinae (ES) and multifidus muscle (MF) were measured, including fatty infiltration (FI) and relative cross-sectional area (rCSA), namely the ratio of the paraspinal muscle CSA to the CSA of the vertebrae of the same segment. Sagittal parameters including lumbar lordosis (LL) and sagittal vertical axis (SVA) were measured. The paraspinal muscle parameters and ES/MF rCSA ratio were compared between the two groups. Paraspinal muscles parameters including rCSA and FI were also compared between each segments from L1 to L5 in both DLS and DLK groups. In order to determine the influence of sagittal spinal alignment on paraspinal muscle parameters, correlation analysis was conducted between the MF, ES, PS rCSA and FI and the LL in DLS and DLK group.

RESULT

MF atrophy is more significant in DLS patients compared with DLK. Also, MF fatty infiltration in the lower lumbar spine of DLS patients was greater compared to DLK patients. DLK patients showed more significant atrophy of ES and heavier ES fatty infiltration. MF FI was significantly different between all adjacent segments in both DLS and DLK groups. In DLS group, ES FI was significantly different between L2/L3 to L3/L4 and L4/L5 to L5/S1, while in DLK group, the difference of ES FI between all adjacent segments was not significant, and ES FI was found negatively correlated with LL.

CONCLUSIONS

Paraspinal muscles show different degeneration patterns in degenerative lumbar diseases. MF degeneration is segmental in both DLS and DLK patients, while ES degenerated diffusely in DLK patients and correlated with the severity of kyphosis. MF degeneration is more significant in the DLS group, while ES degeneration is more significant in DLK patients. MF is the stabilizer of the lumbar spine segments, while the ES tends to maintain the spinal sagittal balance.

The Effect of Posterior Lumbar Spinal Surgery on Biomechanical Properties of Rat Paraspinal Muscles 13 Weeks After Surgery

STUDY DESIGN

Preclinical study in rodents.

OBJECTIVE

To investigate changes in biomechanical properties of paraspinal muscles following a posterior spinal surgery in an animal model.

SUMMARY OF BACKGROUND DATA

Posterior spine surgery damages paraspinal musculature per histological and imaging studies. The biomechanical effects of these changes are unknown.

METHODS

12 Sprague-Dawley rats were divided equally into sham and surgical injury (SI) groups. For sham, the skin and lumbodorsal fascia were incised at midline. For SI, the paraspinal muscles were detached from the vertebrae, per normal procedure. Thirteen weeks postsurgery, multifidus and longissimus biopsies at L1, L3, and L5 levels were harvested on the right. From each biopsy, three fibers and three to six bundles of fibers (∼10-20 fibers ensheathed in their extracellular matrix) were tested mechanically to measure their passive elastic modulus. The collagen content and fatty infiltration of each biopsy were also examined histologically by immunofluorescence staining. Nonparametric statistical methods were used with a 1.25% level of significance.

RESULTS

A total of 220 fibers and 279 bundles of fibers were tested. The elastic moduli of the multifidus and longissimus fibers and longissimus fiber bundles were not significantly different between the SI and sham groups. However, the elastic modulus of multifidus fiber bundles was significantly greater in the SI group compared to sham (SI median 82 kPa, range 23-284; sham median 38 kPa, range 23-50, P = 0.0004). The elastic modulus of multifidus fiber bundles in the SI group was not statistically different between spinal levels (P = 0.023). For histology, only collagen I deposition in multifidus was significantly greater in the SI group (median 20.8% vs. 5.8% for sham, P < 0.0001).

CONCLUSION

The surgical injury increased the passive stiffness of the multifidus fiber bundles. Increased collagen content in the extracellular matrix is the likely reason and these changes may be important in the postoperative compensation of the spine.Level of Evidence: N/A.

How I do it: mini invasive transforaminal lumbar interbody fusion

BACKGROUND

Minimally invasive approaches for lumbar fusion are aimed at reducing soft tissue injury in order to minimize surgical morbidity and facilitate recovery.

METHOD

Applied to lumbar fusion, such an approach is described as a mini-open transforaminal lumbar interbody fusion (TLIF). Important anatomical landmarks are reviewed. Indications, advantages, and limitations are discussed, and a step-by-step description of the procedure is presented.

RESULTS

Decompression, fixation, and bone grafting can be achieved efficiently through this approach with lesser blood loss, shorter hospital stay, reduced rate of general complications, and infections as well as a lower readmission rate.

CONCLUSION

The mini-open TLIF technique, as presented here, is a safe and efficient procedure to achieve lumbar fusion with a reduced rate of complications related to surgery.

Pedicled Multifidus Muscle Flap To Treat Inaccessible Dural Tear In Spine Surgery: Technical Note And Preliminary Experience

OBJECTIVE

To assess the usefulness, feasibility, and limitations of pedicled multifidus muscle flaps (PMMFs) for the treatment of inaccessible dural tears during spine surgery.

METHODS

The technique of PMMF harvesting was investigated together with relevant anatomy. We prospectively evaluated 8 patients treated with the PMMF technique between January 2017 and December 2019. Results were compared with a retrospective series of 9 patients treated with a standard technique between January 2014 and December 2016. Inclusion criteria were inaccessible dural tear or dural tear judged not amenable to direct repair because of tissue loosening. Exclusion criteria were surgical treatment of intradural disease. Clinical and demographic data of all patients were collected. Clinical evaluations were performed according to American Spinal Injury Association criteria and Oswestry Disability Index. Preoperative and postoperative computed tomography was performed in all patients. The primary end point was wound healing (cerebrospinal fluid leakage, infection, and fluid collection); secondary end points were neurologic outcome and complications.

RESULTS

Control group: 1 death as a result of wound infection secondary to cerebrospinal fluid fistula and 2 patients needed lumbar subarachnoid drain; neurologic outcome: 3 patients improved and 6 were unchanged. Flap group: no wound-related complications were observed; neurologic outcome: 3 patients improved and 5 were unchanged. No flap-related complications were described. Flap harvesting was feasible in all cases, with an average 20 minutes adjunctive surgical time.

CONCLUSIONS

The PMMF technique was feasible and safe; in this preliminary experience, its use is associated with lower complications as a result of dural tears but larger series are needed to confirm its effectiveness.

Biportal endoscopic spine surgery (BESS): considering merits and pitfalls

The biportal endoscopic spine surgery allow us to use conventional spine surgical instruments in the endoscopic procedure like open surgery. And protection of the neural structures with assistant retractor make this procedure safer than the uniportal endoscopic spine surgery. The authors present a novel technique in treating degenerative spinal diseases in variable access angle different from the conventional uniportal endoscopic spine surgeries. The main objective of this report is presenting two approaches for central and extraforaminal stenosis using an assistant retractor. Both central and foraminal stenosis were well decompressed and a migrated disc fragment was removed successfully with this minimal endoscopic procedure without major complications in these cases.

Association between back muscle degeneration and spinal-pelvic parameters in patients with degenerative spinal kyphosis

Background

The paraspinal and psoas muscles have been considered to be essentially important for stabilizing the spinal column, and the muscle degeneration was found to exist in degenerative spinal kyphosis (DSK) patients. However, it is still not clear the relationship between muscle degeneration and spinal-pelvic alignment. The purpose of this study was to determine the correlations between the individual muscle degeneration at each lumbar spinal level and spinal-pelvic parameters in DSK patients.

Methods

The imaging data of 32 patients with DSK were retrospectively analyzed. The fat infiltration (FI) and relative cross-sectional area of muscle (RCSA) were quantitatively measured for multifidus (MF), erector spinae (ES) and psoas (PS) at each spinal level from L1/2 to L5/S1. The correlations were analyzed between RCSA and the sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI).

Results

The FI of MF and ES at L3/4, L4/5 and L5/S1 were higher than that at L1/2 and L2/3. The FI of PS at L4/5 and L5/S1 were lower than that of L1/2, L2/3 and L3/4. The RCSA of ES and PS from L1/2 to L5/S1 gradually increased, whereas the RCSA of ES from L1/2 to S5/S1 gradually decreased. The RCSA of MF at the L1/2 level was negatively correlated SVA (r = − 0.397,p = 0.024); the RCSA at L3/4, L4/5 and L5/S1 levels were negatively correlated with TK (r = − 0.364, p = 0.04; r = − 0.38, p = 0.032; r = − 0.432, p = 0.014); the RCSA at L4/5 level was positively correlated with LL (r = 0.528, p = 0.002). The RCSA of ES at L3/4 and L4/5 levels were positively correlated with PI (r = 0.377, p = 0.037) and SS (r = 0.420, p = 0.019).

Conclusions

FI of MF and ES at lower lumbar level is higher than that at upper level, but FI of PS at upper lumbar level is higher than that at lower level. MF and ES have different roles for maintaining the sagittal spinal-pelvic balance.

Limitations in clinical outcome after posterior stabilization of thoracolumbar fractures do not correlate with dynamic trunk muscle dysfunction: an ultrasound controlled prospective cohort study

BACKGROUND AND PURPOSE

Posterior stabilization of the spine is associated with iatrogenic muscle damage. This is discussed to represent an important cause of postoperative pain, especially in open reduction and fixation. The aim of this study was to visualize muscular changes after open or percutaneous posterior stabilization of traumatic thoracolumbar spine fractures and to investigate whether or not these changes are related to the clinical outcome.

METHODS

This prospective cohort study was performed between 05/2012 and 10/2014. A group of posteriorly stabilized patients (study group; SG) with traumatic fractures (AOSpine Type A3 or A4) of the thoracolumbar junction (T11-L2) without neurological deficit were matched to a healthy control group (CG) by age, gender and body mass index.

FOLLOW-UP

12 months after surgery.

PARAMETERS

muscle size, voluntary muscular activation (VMA) using a standardized ultrasound protocol and standardized questionnaires (VAS Spine Score; ODI; SF-36) were analyzed.

STATISTICS

SPSS (Version 20, 76 Chicago, IL, USA). T test, Chi squared test, analysis of variance and a correlation analysis were performed. Significance level was at p < 0.05.

RESULTS

Twenty-five patients (SG) and 23 control individuals (CG) were included. At follow-up, voluntary muscular activation of the lumbar multifidus (LM) as well as the transverse abdominis muscle (TrA) was diminished in all patients compared to the control group (VMA LM at level L3/4: SG 3.2%; CG 5.1%; p < 0.05; VMA TrA: SG 33.43%; CG 37.84%; p < 0.05). Concomitant interviews revealed health restrictions in all patients when compared with the control group. A correlation between muscle function and clinical outcome could not been demonstrated (rs > 0.07; NS).

CONCLUSION

In surgically treated A3 and A4 fractures, there is continuous muscular deficit 1 year after surgery as documented by ultrasound and clinical control. But, by means of our study we conclude that those muscular deficits alone seem not to be decisive for the clinical outcome 1 year after surgery.

Multifidus Muscle Atrophy Not Observed Following Two-segment Anterior Interbody Fusion: A Rabbit Model Study With a 12-Month Follow-up

STUDY DESIGN

Experimental study evaluated magnetic resonance imaging (MRI) and histologic changes in the multifidus muscle after anterior spinal fusion.

OBJECTIVE

To determine the effect of spinal fusion on the multifidus muscle in an anterior rabbit model through the use of MRI and histologic evaluation.

SUMMARY OF BACKGROUND DATA

Retraction and splitting approach are known to be important factors in postoperative injury and atrophy of the multifidus muscle. The effect and possible mechanism of spinal fusion as an independent factor remains unknown.

METHODS

Thirty-six New Zealand white rabbits were divided into two groups. Animals in the fusion group underwent two-level anterior spinal fusion whereas those in the control group underwent similar surgery without spinal fusion. The status of the multifidus muscle was evaluated with MRI and histological analysis at preoperative, 3 weeks, 6 weeks, 3 months, 6 months, and 12 months postoperatively.

RESULTS

All rabbits in the fusion group achieved solid fusion. The mean T1-weighted and T2-weighted signal intensity ratios of gross multifidus to psoas muscles were all approximately 1.0 postoperatively, with no remarkable difference between the groups. The mean lesser diameter of myofibrils in either group did not significantly differ between the preoperative and postoperative specimens. There was no significant fibrotic change or fatty degeneration for either group. Decrease in acetylcholine activity or granular degeneration of the neuromuscular junction were not observed, and normal shape and size were found in nearly all samples at all time points in both groups (P > 0.05).

CONCLUSION

After two-segment anterior spinal fusion, multifidus atrophy was not observed throughout a 12-month follow up. The rabbit model of anterior fusion is better suited to study the effect of fusion alone on the status of the multifidus muscle.

LEVEL OF EVIDENCE

3.

How I do it? Biportal endoscopic spinal surgery (BESS) for treatment of lumbar spinal stenosis

BACKGROUND

Prevalent endoscopic spine surgeries have shown limitations especially in spinal stenosis (Ahn in Neurosurgery 75(2):124-133, 2014). Biportal endoscopic surgery is introduced to manage central and foraminal stenosis with its wide range of access angle and clear view.

METHODS

The authors provide an introduction of this technique followed by a description of the surgical anatomy with discussion on its indications and advantages. In particular, tricks to avoid complications are also presented.

CONCLUSIONS

Effective circumferential and focal decompression were achieved in most cases without damage to the spinal structural integrity with preservation of muscular and ligamentous attachments. The biportal endoscopic spinal surgery (BESS) may be safely used as an alternative minimally invasive procedure for lumbar spinal stenosis (Figs. 1 and 2).

Erector Spinal Muscular Schwannoma of the Dorsal Ramus Nerve: A Case Report

We present a rare case of intramuscular schwannoma originating from the dorsal ramus nerve in a 62-year-old woman. The mass grew slowly, with pain developing upon touch five years prior. No neurological deficit was detected. The mass was observed in the erector spinae muscles in magnetic resonance imaging (MRI), and surgical excision was performed. The mass was well encapsulated with clear margin. The lesion appeared to originate from the cranial side. We completely removed the mass including the origin. Histopathology confirmed a schwannoma diagnosis. This is the first report, to our knowledge, of a dorsal ramus-nerve schwannoma within the erector spinae muscles.