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1.  The Quantitative Analysis of Back Muscle Degeneration after Posterior Lumbar Fusion: Comparison of Minimally Invasive and Conventional Open Surgery 
Asian Spine Journal  2009;3(2):89-95.
Study Design
Prospective controlled study.
Purpose
The results of conventional open surgery was compared with those from minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for lumbar fusion to determine which approach resulted in less postoperative paraspinal muscle degeneration.
Overview of Literature
MI TLIF is new surgical technique that appears to minimize iatrogenic injury. However, there aren't any reports yet that have quantitatively analyzed and proved whether there's difference in back muscle injury and degeneration between the minimally invasive surgery and conventional open surgery in more than 1 year follow-up after surgery.
Methods
This study examined a consecutive series of 48 patients who underwent lumbar fusion in our hospital during the period, March 2006 to March 2008, with a 1-year follow-up evaluation using MRI. There were 17 cases of conventional open surgery and 31 cases of MI-TLIF (31 cases of single segment fusion and 17 cases of multi-segment fusion). The digital images of the paravertebral back muscles were analyzed and compared using the T2-weighted axial images. The point of interest was the paraspinal muscle of the intervertebral disc level from L1 to L5. Picture archiving and communication system viewing software was used for quantitative analysis of the change in fat infiltration percentage and the change in cross-sectional area of the paraspinal muscle, before and after surgery.
Results
A comparison of the traditional posterior fusion method with MI-TLIF revealed single segment fusion to result in an average increase in fat infiltration in the paraspinal muscle of 4.30% and 1.37% and a decrease in cross-sectional area of 0.10 and 0.07 before and after surgery, respectively. Multi-segment fusion showed an average 7.90% and 2.79% increase in fat infiltration and a 0.16 and 0.10 decrease in cross-sectional area, respectively. Both single and multi segment fusion showed less change in the fat infiltration percentage and cross-sectional area, particularly in multi segment fusion. There was no significant difference between the two groups in terms of the radiologic results.
Conclusions
A comparison of conventional open surgery with MI-TLIF upon degeneration of the paraspinal muscle with a 1 year follow-up evaluation revealed that both single and multi segment fusion showed less change in fat infiltration percentage and cross-sectional area in the MI-TLIF but there was no significant difference between the two groups. This suggests that as time passes after surgery, there is no significant difference in the level of degeneration of the paraspinal muscle between surgical techniques.
doi:10.4184/asj.2009.3.2.89
PMCID: PMC2852079  PMID: 20404953
Paraspainal muscle; Fat degeneration; MRI; Posterior fusion
2.  Spinous process-splitting open pedicle screw fusion provides favorable results in patients with low back discomfort and pain compared to conventional open pedicle screw fixation over 1 year after surgery 
European Spine Journal  2012;21(4):745-753.
Introduction
The conventional open pedicle screw fusion (PSF) requires an extensive detachment of the paraspinal muscle from the posterior aspect of the lumbar spine, which can cause muscle injury and subsequently lead to “approach-related morbidity”. The spinous process-splitting (SPS) approach for decompression, unilateral laminotomy for bilateral decompression, and the Wiltse approach for pedicle screw insertion are considered to be less invasive to the paraspinal musculature. We investigated whether SPS open PSF combined with the abovementioned techniques attenuates the paraspinal muscle damage and yields favorable clinical results, including alleviation in the low back discomfort, in comparison to the conventional open PSF.
Methods
We studied 53 patients who underwent single-level PSF for the treatment of degenerative spondylolisthesis (27 patients underwent SPS open PSF and the other 26 underwent the conventional open PSF). The clinical outcomes were assessed using the Japanese Orthopedic Association (JOA) score, the Roland–Morris disability questionnaire (RDQ), and the visual analog scale (VAS) for low back pain and low back discomfort (heavy feeling or stiffness). Postoperative multifidus (MF) atrophy was evaluated using MRI. Follow-up examinations were performed at 1 and 3 years after the surgery.
Results
Although there was no significant difference in the JOA and RDQ score between the two groups, the VAS score for low back pain and discomfort after the surgery were significantly lower in the SPS open PSF group than in the conventional open PSF group. The extent of MF atrophy after SPS open PSF was reduced more significantly than after the conventional open PSF during the follow-up. The MF atrophy ratio was found to correlate with low back discomfort at the 1-year follow-up examination.
Conclusion
In conclusion, SPS open PSF was less damaging to the paraspinal muscle than the conventional open PSF and had a significant clinical effect, reducing low back discomfort over 1 year after the surgery.
doi:10.1007/s00586-011-2146-2
PMCID: PMC3326135  PMID: 22237851
Posterior lumbar fusion; Multifidus muscle; Wiltse approach; Minimally invasive; Conventionally open
3.  Paraspinal Muscle Sparing versus Percutaneous Screw Fixation : A Prospective and Comparative Study for the Treatment of L5-S1 Spondylolisthesis 
Objective
Both the paraspinal muscle sparing approach and percutaneous screw fixation are less traumatic procedures in comparison with the conventional midline approach. These techniques have been used with the goal of reducing muscle injury. The purpose of this study was to evaluate and to compare the safety and efficacy of the paraspinal muscle sparing technique and percutaneous screw fixation for the treatment of L5-S1 spondylolisthesis.
Methods
Twenty patients who had undergone posterior lumbar interbody fusion (PLIF) at the L5-S1 segment for spondylolisthesis were prospectively studied. They were divided into two groups by screw fixation technique (Group I : paraspinal muscle sparing approach and Group II: percutaneous screw fixation). Clinical outcomes were assessed by Low Back Outcome Score (LBOS) and Visual Analogue Scale (VAS) for back and leg pain at different times after surgery. In addition, modified MacNab's grading criteria were used to assess subjective patients' outcomes 6 months after surgery. Postoperative midline surgical scarring, intraoperative blood loss, mean operation time, and procedure-related complications were analyzed.
Results
Excellent or good results were observed in all patients in both groups 6 months after surgery. Patients in both groups showed marked improvement in terms of LBOSs all over time intervals. Postoperative midline surgical scarring and intraoperative blood loss were lower in Group II compared to Group I although these differences were not statistically significant. Low back pain (LBP) and leg pain in both groups also showed significant improvement when compared to preoperative scores. However, at 7 days and 1 month after surgery, patients in Group II had significantly better LBP scores compared to Group I.
Conclusion
In terms of LBP during the early postoperative period, patients who underwent percutaneous screw fixation showed better results compared to ones who underwent screw fixation via the paraspinal muscle sparing approach. Our results indicate that the percutaneous screw fixation procedure is the preferable minimally invasive technique for reducing LBP associated with L5-S1 spondylolisthesis.
doi:10.3340/jkns.2011.49.3.163
PMCID: PMC3085812  PMID: 21556236
Spondylolisthesis; Paraspinal muscle sparing approach; Percutaneous screw fixation; Back pain
4.  Postoperative Changes in Paraspinal Muscle Volume: Comparison between Paramedian Interfascial and Midline Approaches for Lumbar Fusion 
Journal of Korean Medical Science  2007;22(4):646-651.
In this study, we compared the paramedian interfascial approach (PIA) and the traditional midline approach (MA) for lumbar fusion to determine which approach resulted in the least amount of postoperative back muscle atrophy. We performed unilateral transforaminal posterior lumbar interbody fusion via MA on the symptomatic side and pedicle screw fixation via PIA on the other side in the same patient. We evaluated the damage to the paraspinal muscle after MA and PIA by measuring the preoperative and postoperative paraspinal muscle volume in 26 patients. The preoperative and postoperative cross-sectional area, thickness, and width of the multifidus muscle were measured by computed tomography. The degree of postoperative paraspinal muscle atrophy was significantly greater on the MA side than on the contralateral PIA side (-20.7% and -4.8%, respectively, p<0.01). In conclusion, the PIA for lumbar fusion yielded successful outcomes for the preservation of paraspinal muscle in these 26 patients. We suggest that the success of PIA is due to less manipulation and retraction of the paraspinal muscle and further studies on this technique may help confirm whether less muscle injury has positive effects on the long-term clinical outcome.
doi:10.3346/jkms.2007.22.4.646
PMCID: PMC2693813  PMID: 17728503
Paraspinal Muscle; Paramedian Approach; Muscle Atrophy; Lumbar Spine
5.  Symmetry of paraspinal muscle denervation in clinical lumbar spinal stenosis: Support for a hypothesis of posterior primary ramus stretching? 
Muscle & nerve  2013;48(2):198-203.
Introduction
Denervation of the paraspinal muscles in spinal disorders is frequently attributed to radiculopathy. Therefore, persons with lumbar spinal stenosis causing asymmetrical symptoms should have asymmetrical paraspinal denervation.
Methods
73 persons with clinical lumbar spinal stenosis, aged 55 to 85, completed a pain drawing and underwent masked electrodiagnostic testing including bilateral paraspinal mapping and testing of 6 muscles on the most symptomatic (or randomly chosen) limb.
Results
With the exception of 10 subjects with unilateral thigh pain (p=0.043), there was no relationship between side of pain and paraspinal mapping score for any subgroups (symmetrical pain, pain into one calf only). Among those with positive limb EMG (tested on one side), no relationship between side of pain and paraspinal EMG score was found.
Discussion
The evidence suggests that paraspinal denervation in spinal stenosis may not be due to radiculopathy, but rather due to stretch or damage to the posterior primary ramus.
doi:10.1002/mus.23750
PMCID: PMC4147036  PMID: 23813584
Spinal stenosis; electrodiagnosis; multifidus; back pain; paraspinal mapping; segmental instability
6.  Lumbar paraspinal and biceps brachii muscle function and movement perception in lumbar spinal stenosis 
European Spine Journal  2012;22(4):788-793.
Introduction
Impaired muscle function and lumbar proprioception have been observed in lumbar spinal stenosis (LSS) but those have not been studied in LSS patients with age-matched controls. We assessed lumbar movement perception and paraspinal and biceps brachii (BB) muscle responses during sudden upper limb loading in age-matched healthy subjects and patients with LSS.
Methods
The study included 30 patients selected for an operation due to LSS and 30 age-matched controls without chronic back pain. The paraspinal and BB muscle responses for upper limb loading during unexpected and expected conditions were measured by surface EMG. The ability to sense lumbar rotation was assessed in a previously validated motorized trunk rotation unit in a seated position. Pain, disability and depression scores were recorded.
Results
Patients had poorer lumbar perception (mean difference 2.3 ± 0.6°, P < 0.001) and longer paraspinal muscle response latencies [mean difference 4.6 ± 0.6 ms (P = 0.033)] than age-matched healthy controls. Anticipation increased paraspinal and BB muscle activation prior to the load perturbation (P < 0.001) but less in LSS patients than in controls [9 vs. 30 %, P = 0.016 (paraspinals); 68 vs. 118 %, P = 0.047 (BB)].
Conclusions
The observed impairments in lumbar proprioception and activation of paraspinal and upper limb muscles indicate an extensive loss of both sensory and motor functions in LSS. The main new finding was decreased anticipatory muscle activation during expected upper limb loading reflecting involvement of central movement control mechanisms.
doi:10.1007/s00586-012-2563-x
PMCID: PMC3631031  PMID: 23179975
Lumbar proprioception; Paraspinal reflexes; Feed-forward control; Low back pain; Lumbar spinal stenosis
7.  Castleman’s disease in the retroperitoneal space mimicking a paraspinal schwannoma: a case report 
Background
Castleman’s disease is a rare disease characterized by lymph node hyperplasia. Its occurrence in the retroperitoneal space has rarely been reported, making its preoperative diagnosis difficult. Here, we report a case of retroperitoneal Castleman’s disease, which radiologically resembled paraspinal schwannoma.
Case presentation
A 33-year-old Japanese man with epigastric discomfort underwent abdominal ultrasonic examination revealing a solid mass next to the right kidney. Computed tomography demonstrated a well-circumscribed mass with central calcification in the right psoas muscle. Because the mass presented a dumbbell-like shape extending to the intervertebral foramen, neurogenic tumor was suspected. Both iodine-123 metaiodobenzylguanidine and gallium-67 scintigraphies were negative in the mass, whereas thallium-201 mildly accumulated in the tumor, suggesting blood flow to the tumor. Positron emission tomography revealed accumulation of fluorine-18-2-fluoro-2-deoxy-d-glucose in the tumor at a standard uptake value of 4.7, whereas no other abnormal uptake suggestive of metastatic lesion was noted. On the basis of imaging studies, we mostly suspected paraspinal schwannoma, although malignancy was not completely excluded. Angiography showed feeding vessels from the right lumbar arteries, which were embolized with porous gelatin particles in order to reduce intraoperative bleeding. Surgical resection was performed using a retroperitoneal approach, which revealed the tumor in the swollen psoas muscle. Intraoperative pathological examination of a frozen section revealed no evidence of malignancy; thus, marginal excision of the tumor was performed. The tumor adhered tightly to surrounding muscle tissues, resulting in 940 g of intraoperative blood loss. The pathological examination demonstrated infiltration of lymphocytes surrounding small germinal centers with extensive capillary proliferation. Immunostaining revealed that proliferated lymphocytes were CD3-negative and CD79a-positive.
Conclusions
Although a dumbbell-shaped mass in a paraspinal region is indicative of a schwannoma for orthopedic surgeons, the possibility of Castleman’s disease should be considered if a central low-signal area in fissured and a radial pattern is detected on computed tomography or magnetic resonance imaging. Appropriate preparation for massive bleeding during the treatment of Castleman’s disease, including angiography and embolization, would be helpful for performing surgical procedures safely.
doi:10.1186/1477-7819-11-108
PMCID: PMC3663832  PMID: 23702327
Castleman’s disease; Dumbbell shape; Paraspinal schwannoma; Soft-tissue sarcoma
8.  Regional Myosin Heavy Chains Distribution in Selected Paraspinal Muscles 
Spine  2010;35(13):1265-1270.
Study Design
Cross-sectional study with repeated measures design.
Objective
To compare the myosin heavy chain isoform distribution within and between paraspinal muscles and to test the theory that fiber type gradients exist as a function of paraspinal muscle depth.
Summary of Background Data
There is still uncertainty regarding the fiber type distributions within different paraspinal muscles. It has been previously proposed that deep fibers of the multifidus muscle may contain a higher ratio of type I to type II fibers, because, unlike superficial fibers, they primarily stabilize the spine, and may therefore have relatively higher endurance. Using a minimally invasive surgical approach, utilizing tubular retractors that are placed within anatomic inter-muscular planes, it was feasible to obtain biopsies from the multifidus, longissimus, iliocostalis and psoas muscles at specific predefined depths.
Methods
Under an IRB approved protocol, muscle biopsies were obtained from 15 patients who underwent minimally invasive spinal surgery, using the posterior paramedian (Wiltse) approach or the minimally invasive lateral approach. Myosin heavy chain (MyHC) isoform distribution was analyzed using SDS-PAGE electrophoresis. Since multiple biopsies were obtained from each patient, MyHC distribution was compared using both within- and between-muscle repeated measures analyses.
Results
The fiber type distribution was similar among the posterior paraspinal muscles and was composed of relatively high percentage of type I (63%), compared to type IIA (19%) and type IIX (18%) fibers. In contrast, the psoas muscle was found to contain a lower percentage of type I fibers (42%) and a higher percentage of type IIA (33%) and IIX fibers (26%; P<0.05). No significant difference was found for fiber type distribution among three different depths of the multifidus and psoas muscles.
Conclusion
Fiber type distribution between the posterior paraspinal muscles is consistent and is composed of relatively high percentage of type I fibers, consistent with a postural function. The psoas muscle, on the other hand, is composed of a higher percentage of type II fibers such as in the appendicular muscles. Our data do not support the idea of a fiber type gradient as a function of depth for any muscle studied.
doi:10.1097/BRS.0b013e3181bfcd98
PMCID: PMC2947743  PMID: 20461040
Lumbar multifidus; Muscle mechanics; Lumbar spine
9.  Reduced Quadriceps Activation After Lumbar Paraspinal Fatiguing Exercise 
Journal of Athletic Training  2006;41(1):79-86.
Context: Although poor paraspinal muscle endurance has been associated with less quadriceps activation (QA) in persons with a history of low back pain, no authors have addressed the acute neuromuscular response after lumbar paraspinal fatiguing exercise.
Objective: To compare QA after lumbar paraspinal fatiguing exercise in healthy individuals and those with a history of low back pain.
Design: A 2 × 4 repeated-measures, time-series design.
Setting: Exercise and Sport Injury Laboratory.
Patients or Other Participants: Sixteen volunteers participated (9 males, 7 females; 8 controls and 8 with a history of low back pain; age = 24.1 ± 3.1 years, height = 173.4 ± 7.1 cm, mass = 72.4 ± 12.1 kg).
Intervention(s): Subjects performed 3 sets of isometric lumbar paraspinal fatiguing muscle contractions. Exercise sets continued until the desired shift in lumbar paraspinal electromyographic median power frequency was observed. Baseline QA was compared with QA after each exercise set.
Main Outcome Measure(s): An electric burst was superimposed while subjects performed a maximal quadriceps contraction. We used the central activation ratio to calculate QA = (FMVIC/[FMVIC + FBurst])* 100, where F = force and MVIC = maximal voluntary isometric contractions. Quadriceps electromyographic activity was collected at the same time as QA measurements to permit calculation of median frequency during MVIC.
Results: Average QA decreased from baseline (87.4% ± 8.2%) after the first (84.5% ± 10.5%), second (81.4% ± 11.0%), and third (78.2% ± 12.7%) fatiguing exercise sets. On average, the group with a history of low back pain showed significantly more QA than controls. No significant change in quadriceps median frequency was noted during the quadriceps MVICs.
Conclusions: The quadriceps muscle group was inhibited after lumbar paraspinal fatiguing exercise in the absence of quadriceps fatigue. This effect may be different for people with a history of low back pain compared with healthy controls.
PMCID: PMC1421484  PMID: 16619099
superimposed burst technique; quadriceps muscle inhibition; low back pain
10.  Lumbar plexopathy following instrumented posterior lumbar interbody fusion: a complication with use of Hohmann’s retractor 
European Spine Journal  2013;22(9):2039-2046.
Introduction
A series of 12 patients in our centre following single level instrumented posterior lumbar interbody fusion at L4–L5 developed unexplainable motor weakness in the proximal lumbar nerve roots (L2, L3) and numbness of the whole limb, a clinical picture resembling lumbar plexopathy. Even though lumbar plexopathy has been reported following gynaecological procedures and in transpsoas interbody fusion surgeries, there is no literature reporting this complication following conventional instrumented posterior lumbar interbody fusions.
Study design
Retrospective observational study.
Objective
To find the possible mechanism of development of lumbar plexopathy in patients who underwent posterior lumbar interbody fusion surgeries in our centre.
Material and methods
We analyzed retrospectively the medical records, electrophysiological reports of the patients, literatures on the anatomy of lumbar plexus and other literature reporting similar complications. We also dissected lumbar plexus of three cadavers and simulated surgical technique on them to find the mechanism of development of this unusual complication.
Results
We found injury to lumbar plexus that probably occurred intraoperatively with Hohmann’s retractor that was used for retraction of the paraspinal muscles. This theory was favoured by many clinical factors and further confirmed by cadaveric dissections.
Conclusion
We conclude that surgical technique with improper use of Hohmann’s retractor causes traction and compression injury to the lumbar plexus resulting in this complication. We propose proper technique of insertion of Hohmann’s retractor and also recommend use of modified Hohmann’s retractor with shorter tips for spinal procedures to prevent such complication.
doi:10.1007/s00586-013-2748-y
PMCID: PMC3777048  PMID: 23543368
Lumbar plexopathy; Instrumented posterior lumbar interbody fusion; Hohmann’s retractor
11.  Metabolism during anaesthesia and recovery in colic and healthy horses: a microdialysis study 
Background
Muscle metabolism in horses has been studied mainly by analysis of substances in blood or plasma and muscle biopsy specimens. By using microdialysis, real-time monitoring of the metabolic events in local tissue with a minimum of trauma is possible. There is limited information about muscle metabolism in the early recovery period after anaesthesia in horses and especially in the colic horse. The aims were to evaluate the microdialysis technique as a complement to plasma analysis and to study the concentration changes in lactate, pyruvate, glucose, glycerol, and urea during anaesthesia and in the recovery period in colic horses undergoing abdominal surgery and in healthy horses not subjected to surgery.
Methods
Ten healthy university-owned horses given anaesthesia alone and ten client-owned colic horses subjected to emergency abdominal surgery were anaesthetised for a mean (range) of 230 min (193–273) and 208 min (145–300) respectively. Venous blood samples were taken before anaesthesia. Venous blood sampling and microdialysis in the gluteal muscle were performed during anaesthesia and until 24 h after anaesthesia. Temporal changes and differences between groups were analysed with an ANOVA for repeated measures followed by Tukey Post Hoc test or Planned Comparisons.
Results
Lactate, glucose and urea, in both dialysate and plasma, were higher in the colic horses than in the healthy horses for several hours after recovery to standing. In the colic horses, lactate, glucose, and urea in dialysate, and lactate in plasma increased during the attempts to stand. The lactate-to-pyruvate ratio was initially high in sampled colic horses but decreased over time. In the colic horses, dialysate glycerol concentrations varied considerably whereas in the healthy horses, dialysate glycerol was elevated during anaesthesia but decreased after standing. In both groups, lactate concentration was higher in dialysate than in plasma. The correspondence between dialysate and plasma concentrations of glucose, urea and glycerol varied.
Conclusion
Microdialysis proved to be suitable in the clinical setting for monitoring of the metabolic events during anaesthesia and recovery. It was possible with this technique to show greater muscle metabolic alterations in the colic horses compared to the healthy horses in response to regaining the standing position.
doi:10.1186/1751-0147-51-10
PMCID: PMC2660341  PMID: 19284560
12.  Back and hip extensor muscles fatigue in healthy subjects: task-dependency effect of two variants of the Sorensen test 
European Spine Journal  2008;17(12):1721-1726.
Paraspinal muscle fatigability during various trunk extension tests has been widely investigated by electromyography (EMG), and its task-dependency is established recently. Hip extensor muscle fatigability during the Sorensen test has been reported. The aim of the present experiments was to evaluate the task-dependency of back and hip extensor muscle fatigue during two variants of the Sorensen test. We hypothesized that the rate of muscular fatigue of the hip and back extensor muscles varies according to the test position. Twenty healthy young males with no history of low back pain volunteered to participate in this cross-sectional study. They were asked to perform two body weight-dependent isometric back extension tests (S1 = Sorensen test; S2 = modified Sorensen on a 45° Roman chair). Surface EMG activity of the paraspinal muscles (T10 and L5 levels) and hip extensor muscles (gluteus maximus; biceps femoris) was recorded, and muscular fatigue was assessed through power spectral analysis of the EMG data by calculating the rate of median power frequency change. We observed hip extensor muscle fatigue simultaneously with paraspinal muscle fatigue during both Sorensen variants. However, only L5 level EMG fatigue indices showed a task-dependency effect between S1 and S2. Hip extensor muscles appear to contribute to load sharing of the upper body mass during both Sorensen variants, but to a different extent because L5 level fatigue differs between the Sorensen variants. Our findings suggest that task-dependency has to be considered when EMG variables are compared between two types of lumbar muscle-fatiguing tasks.
doi:10.1007/s00586-008-0782-y
PMCID: PMC2587667  PMID: 18813961
Erector spinae; Hip extensors; Sorensen test; Muscle fatigability; Task-dependency
13.  Jogging Kinematics After Lumbar Paraspinal Muscle Fatigue 
Journal of Athletic Training  2009;44(5):475-481.
Abstract
Context:
Isolated lumbar paraspinal muscle fatigue causes lower extremity and postural control deficits.
Objective:
To describe the change in body position during gait after fatiguing lumbar extension exercises in persons with recurrent episodes of low back pain compared with healthy controls.
Design:
Case-control study.
Setting:
Motion analysis laboratory.
Patients or Other Participants:
Twenty-five recreationally active participants with a history of recurrent episodes of low back pain, matched by sex, height, and mass with 25 healthy controls.
Intervention(s):
We measured 3-dimensional lower extremity and trunk kinematics before and after fatiguing isometric lumbar paraspinal exercise.
Main Outcome Measure(s):
Measurements were taken while participants jogged on a custom-built treadmill surrounded by a 10-camera motion analysis system.
Results:
Group-by-time interactions were observed for lumbar lordosis and trunk angles (P < .05). A reduced lumbar spine extension angle was noted, reflecting a loss of lordosis and an increase in trunk flexion angle, indicating increased forward trunk lean, in healthy controls after fatiguing lumbar extension exercise. In contrast, persons with a history of recurrent low back pain exhibited a slight increase in spine extension, indicating a slightly more lordotic position of the lumbar spine, and a decrease in trunk flexion angles after fatiguing exercise. Regardless of group, participants experienced, on average, greater peak hip extension after lumbar paraspinal fatigue.
Conclusions:
Small differences in response may represent a necessary adaptation used by persons with recurrent low back pain to preserve gait function by stabilizing the spine and preventing inappropriate trunk and lumbar spine positioning.
doi:10.4085/1062-6050-44.5.475
PMCID: PMC2742456  PMID: 19771285
gait analysis; spine
14.  Technical Changes in Paraspinous Muscle Flap Surgery Have Increased Salvage Rates of Infected Spinal Wounds 
Eplasty  2008;8:e50.
Objectives: The objective of this study is to introduce modifications in paraspinous muscle flap surgery and compare this new variation's ability to salvage infected hardware with the classic technique. Infected posterior spine wounds are a difficult problem for reconstructive surgeons. As per experience, hardware retention in infected wounds maintains spinal stability, decreases length of stay, and decreases the wound healing complication rate. Methods: An 11-year retrospective office and hospital chart review was conducted between July 1996 and August 2007. All patients who underwent paraspinous muscle flap reconstruction for postspine surgery wound infections during this time period were included. There were 51 patients in the study representing the largest reported series, to date, for this procedure. Twenty-two patients underwent treatment using the modified technique and 29 patients were treated using the classic technique. Results: There was no statistical difference between the 2 groups in demographics, medical history, or reason for initial spine surgery. The hardware salvage rate associated with the modified technique was greater than the rate associated with the classic technique (95.4% vs 75.8%; P = .03). There were fewer postreconstruction wound healing complications requiring hospital readmission in the modified technique group than the classic group (13.6% vs 44.8%; P = .04). Patients in the modified technique group demonstrated a shorter mean length of stay than the patients in the classic group (23.7 days vs 29.7; P = .25). Conclusions: The modified paraspinous muscle flap technique is an excellent option for spinal wound reconstruction, preservation of spinal hardware, and local infection control.
PMCID: PMC2570115  PMID: 19011678
15.  Acute camptocormia induced by olanzapine: a case report 
Introduction
Camptocormia refers to an abnormal posture with flexion of the thoraco-lumbar spine which increases during walking and resolves in supine position. This symptom is an increasingly recognized feature of parkinsonian and dystonic disorders, but may also be caused by neuromuscular diseases. There is recent evidence that both central and peripheral mechanisms may be involved in the pathogenesis of camptocormia. We report a case of acute onset of camptocormia, a rare side effect induced by olanzapine, a second-generation atypical anti-psychotic drug with fewer extra-pyramidal side-effects, increasingly used as first line therapy for schizophrenia, delusional disorders and bipolar disorder.
Case presentation
A 73-year-old Caucasian woman with no history of neuromuscular disorder, treated for chronic delusional disorder for the last ten years, received two injections of long-acting haloperidol. She was then referred for fatigue. Physical examination showed a frank parkinsonism without other abnormalities. Routine laboratory tests showed normal results, notably concerning creatine kinase level. Fatigue was attributed to haloperidol which was substituted for olanzapine. Our patient left the hospital after five days without complaint. She was admitted again three days later with acute back pain. Examination showed camptocormia and tenderness in paraspinal muscles. Creatine kinase level was elevated (2986 UI/L). Magnetic resonance imaging showed necrosis and edema in paraspinal muscles. Olanzapine was discontinued. Pain resolved quickly and muscle enzymes were normalized within ten days. Risperidone was later introduced without significant side-effect. The camptocormic posture had disappeared when the patient was seen as an out-patient one year later.
Conclusions
Camptocormia is a heterogeneous syndrome of various causes. We believe that our case illustrates the need to search for paraspinal muscle damage, including drug-induced rhabdomyolysis, in patients presenting with acute-onset bent spine syndrome. Although rare, the occurrence of camptocormia induced by olanzapine must be considered.
doi:10.1186/1752-1947-4-192
PMCID: PMC2904791  PMID: 20579377
16.  Activations of Deep Lumbar Stabilizing Muscles by Transcutaneous Neuromuscular Electrical Stimulation of Lumbar Paraspinal Regions 
Annals of Rehabilitation Medicine  2014;38(4):506-513.
Objective
To investigate changes in lumbar multifidus (LM) and deep lumbar stabilizing abdominal muscles (transverse abdominis [TrA] and obliquus internus [OI]) during transcutaneous neuromuscular electrical stimulation (NMES) of lumbar paraspinal L4-L5 regions using real-time ultrasound imaging (RUSI).
Methods
Lumbar paraspinal regions of 20 healthy physically active male volunteers were stimulated at 20, 50, and 80 Hz. Ultrasound images of the LM, TrA, OI, and obliquus externus (OE) were captured during stimulation at each frequency.
Results
The thicknesses of superficial LM and deep LM as measured by RUSI were greater during NMES than at rest for all three frequencies (p<0.05). The thicknesses in TrA, OI, and OE were also significantly greater during NMES of lumbar paraspinal regions than at rest (p<0.05).
Conclusion
The studied transcutaneous NMES of the lumbar paraspinal region significantly activated deep spinal stabilizing muscle (LM) and the abdominal lumbar stabilizing muscles TrA and OI as evidenced by RUSI. The findings of this study suggested that transcutaneous NMES might be useful for improving spinal stability and strength in patients having difficulty initiating contraction of these muscles.
doi:10.5535/arm.2014.38.4.506
PMCID: PMC4163590  PMID: 25229029
Transcutaneous neuromuscular electrical stimulation; Lumbar stabilizing muscle; Real-time ultrasound imaging; Lumbar multifidus; Transverse abdominis
17.  Mitochondrial DNA deletions and depletion within paraspinal muscles 
Aims
Although mitochondrial abnormalities have been reported within paraspinal muscles in patients with axial weakness and neuromuscular disease as well as with ageing, the basis of respiratory deficiency in paraspinal muscles is not known. This study aimed to determine the extent and basis of respiratory deficiency in paraspinal muscles from cases undergoing surgery for degenerative spinal disease and post mortem cases without a history of spinal disease, where age-related histopathological changes were previously reported.
Methods
Cervical and lumbar paraspinal muscles were obtained peri-operatively from 13 patients and from six post mortem control cases (age range 18–82 years) without a neurological disease. Sequential COX/SDH (mitochondrial respiratory chain complex IV/complex II) histochemistry was performed to identify respiratory-deficient muscle fibres (lacking complex IV with intact complex II activity). Real-time polymerase chain reaction, long-range polymerase chain reaction and sequencing were used to identify and characterize mitochondrial DNA (mtDNA) deletions and determine mtDNA copy number status. Mitochondrial respiratory chain complex subunits were detected by immunohistochemistry.
Results
The density of respiratory-deficient fibres increased with age. On average, 3.96% of fibres in paraspinal muscles were respiratory-deficient (range 0–10.26). Respiratory deficiency in 36.8% of paraspinal muscle fibres was due to clonally expanded mtDNA deletions. MtDNA depletion accounted for further 13.5% of respiratory deficiency. The profile of immunohistochemically detected subunits of complexes was similar in respiratory-deficient fibres with and without mtDNA deletions or mtDNA depletion.
Conclusions
Paraspinal muscles appeared to be particularly susceptible to age-related mitochondrial respiratory chain defects. Clonally expanded mtDNA deletions and focal mtDNA depletion may contribute towards the development of age-related postural abnormalities.
doi:10.1111/j.1365-2990.2012.01290.x
PMCID: PMC4063338  PMID: 22762368
ageing; mitochondrial DNA deletion; paraspinal muscle
18.  Treatment of multilevel degenerative lumbar spinal stenosis with spondylolisthesis using a combination of microendoscopic discectomy and minimally invasive transforaminal lumbar interbody fusion 
Degenerative lumbar spinal stenosis (DLSS) has become increasingly common and is characterized by multilevel disc herniation and lumbar spondylolisthesis, which are difficult to treat. The current study aimed to evaluate the short-term clinical outcomes and value of the combined use of microendoscopic discectomy (MED) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for the treatment of multilevel DLSS with spondylolisthesis, and to compare the combination with traditional posterior lumbar interbody fusion (PLIF). A total of 26 patients with multilevel DLSS and spondylolisthesis underwent combined MED and MI-TLIF surgery using a single cage and pedicle rod-screw system. These cases were compared with 27 patients who underwent traditional PLIF surgery during the same period. Data concerning incision length, surgery time, blood loss, time of bed rest and Oswestry Disability Index (ODI) score prior to and following surgery were analyzed statistically. Statistical significance was reached in terms of incision length, blood loss and the time of bed rest following surgery (P<0.05), but there was no significant difference between the surgery time and ODI scores of the two groups. The combined use of MED and MI-TLIF has the advantages of reduced blood loss, less damage to the paraspinal soft tissue, shorter length of incision, shorter bed rest time, improved outcomes and shorter recovery times and has similar short-term clinical outcomes to traditional PLIF.
doi:10.3892/etm.2012.812
PMCID: PMC3570089  PMID: 23403827
microendoscopic discectomy; minimally invasive transforaminal lumbar interbody fusion; posterior lumbar interbody fusion; lumbar spinal stenosis; lumbar spondylolisthesis
19.  Analysis of Factors Contributing to Postoperative Spinal Instability after Lumbar Decompression for Spinal Stenosis 
Korean Journal of Spine  2013;10(3):149-154.
Objective
Decompressive laminectomy is one of the most commonly used surgical methods for the treatment of spinal stenosis. We retrospectively examined the risk factors that induce spinal instability, including slippage (spondylolisthesis) and/or segmental angulation after decompressive laminectomy on the lumbar spine.
Methods
From January 1, 2006 to June 30, 2010, 94 consecutive patients underwent first-time single level decompressive laminectomy without fusion and discectomy. Of these 94 patients, 42 with a follow-up period of at least 2 years were selected. We measured the segmental angulation and slippage in flexion and extension dynamic lumbar radiographs. We analyzed the following contributing factors to spinal instability: age/sex, smoking history, disc space narrowing, body mass index (kg/m2), facet joint tropism, effect of the lordotic angle on lumbar spine, asymmetrical paraspinal muscle volume, and surgical method and level.
Results
Female patients, normal lordotic angle, and asymmetrical paraspinal muscle volume were factors more significantly associated with spondylolisthesis (p-value=0.026, 0.015, <0.01). Statistical results indicated that patients with facet tropism were more likely to have segmental angulation (p-value=0.046). Facet tropism and asymmetry of paraspinal muscle volume were predisposing factors to spinal instability (p-value=0.012, <0.01).
Conclusion
Facet joint tropism and asymmetry of paraspinal muscle volume are the most important factors associated with spinal instability; therefore, careful follow-up after decompressive laminectomy in affected patients is necessary.
doi:10.14245/kjs.2013.10.3.149
PMCID: PMC3941765  PMID: 24757477
Spinal stenosis; Facet tropism; Paraspinal muscle; Instability
20.  TIME COURSE FOR THE DEVELOPMENT OF MUSCLE HISTORY IN LUMBAR PARASPINAL MUSCLE SPINDLES ARISING FROM CHANGES IN VERTEBRAL POSITION 
Background Context
In neutral spinal postures with low loading moments the lumbar spine is not inherently stable. Small compromises in paraspinal muscle activity may affect lumbar spinal biomechanics. Proprioceptive feedback from muscle spindles is considered important for control of muscle activity. Because skeletal muscle and muscle spindles are thixotropic, their length history changes their physical properties. The present study explores a mechanism that can affect the responsiveness of paraspinal muscle spindles in the lumbar spine.
Purpose
This study had two aims: to extend our previous findings demonstrating the history dependent effects of vertebral position on the responsiveness of lumbar paraspinal muscle spindles; and to determine the time course for these effects. Based upon previous studies, if a crossbridge mechanism underlies these thixotropic effects, then the relationship between the magnitude of spindle discharge and the duration of the vertebral position will be one of exponential decay or growth.
Study Design/Setting
A neurophysiological study using the lumbar spine of a feline model.
Methods
The discharge from individual muscle spindles afferents innervating lumbar paraspinal muscles in response to the duration and direction of vertebral position were obtained from teased filaments in the L6 dorsal roots of 30 Nembutal-anesthetized cats. The L6 vertebra was controlled using a displacement-controlled feedback motor and was held in each of 3 different conditioning positions for durations of 0, 0.5, 1, 1.5, and 2 seconds. Two of the conditioning positions stretched or shortened the lumbar muscles relative to an intermediate conditioning position. Conditioning positions for all cats ranged from 0.9 – 2.0 mm dorsal and ventralward relative to the intermediate position. These magnitudes were determined based upon the displacement that loaded the L6 vertebra to 50–60% of the cat’s body weight. Conditioning was thought to simulate a motion segment’s position that might be passively maintained due to fixation, external load, a prolonged posture, or structural change. Following conditioning positions that stretched (hold-long) and shortened (hold-short) the spindle, the vertebra was repositioned identically and muscle spindle discharge at rest and to movement was compared with conditioning at the intermediate position.
Results
Lumbar vertebral positions maintained for less than 2 seconds were capable of evoking different discharge rates from lumbar paraspinal muscle spindles despite the vertebra having been returned to identical locations. Both resting spindle discharge and their responsiveness to movement were altered. Conditioning vertebral positions that stretched the spindles decreased spindle activity and positions that unloaded the spindles increased spindle activity upon returning the vertebra to identical original (intermediate) positions. The magnitude of these effects increased as conditioning duration increased to 2 seconds. These effects developed with a time course following a first order exponential reaching a maximal value after approximately 4 seconds of history. The time constant for a hold-short history was 2.6 seconds and for a hold-long history was approximately half of that at 1.1 seconds.
Conclusions
Thixotropic contributions to the responsiveness of muscles spindles in the low back are caused by the rapid, spontaneous formation of stable crossbridges. These sensory alterations due to vertebral history would represent a proprioceptive input not necessarily representative of the current state of intersegmental positioning. As such, they would constitute a source of inaccurate sensory feedback. Examples are presented suggesting ways in which this novel finding may affect spinal physiology.
doi:10.1016/j.spinee.2007.05.009
PMCID: PMC2366132  PMID: 17938002
21.  RESPONSE OF LUMBAR PARASPINAL MUSCLES SPINDLES IS GREATER TO SPINAL MANIPULATIVE LOADING COMPARED WITH SLOWER LOADING UNDER LENGTH CONTROL 
Background Context
Spinal manipulation (SM) is a form of manual therapy used clinically to treat patients with low back and neck pain. The most common form of this maneuver is characterized as a high velocity (duration < 150ms), low amplitude (segmental translation < 2mm, rotation < 4°, and applied force 220-889N) impulse thrust (HVLA-SM). Clinical skill in applying an HVLA-SM lies in the practitioner's ability to control the duration and magnitude of the load (i.e., the rate of loading), the direction in which the load is applied, and the contact point at which the load is applied. Control over its mechanical delivery presumably related to its clinical effects. Biomechanical changes evoked by an HVLA-SM are thought to have physiological consequences caused, at least in part, by changes in sensory signaling from paraspinal tissues.
Purpose
If activation of afferent pathways does contribute to the effects of an HVLA-SM, it seems reasonable to anticipate that neural discharge might increase or decrease in a non-linear fashion as the thrust duration thrust approaches a threshold value. We hypothesized that the relationship between the duration of an impulsive thrust to a vertebra and paraspinal muscle spindle discharge would be non-linear with an inflection near the duration of an HVLA-SM delivered clinically (<150ms). In addition, we anticipated that muscle spindle discharge would be more sensitive to larger amplitude thrusts.
Study Design/Setting
A neurophysiological study of spinal manipulation using the lumbar spine of a feline model.
Methods
Impulse thrusts (duration: 12.5, 25, 50, 100, 200, and 400 ms; amplitude 1 or 2mm posterior to anterior) were applied to the spinous process of the L6 vertebra of deeply anesthetized cats while recording single unit activity from dorsal root filaments of muscle spindle afferents innervating the lumbar paraspinal muscles. A feedback motor was used in displacement control mode to deliver the impulse thrusts. The motor's drive arm was securely attached to the L6 spinous process via a forceps.
Results
As thrust duration became shorter the discharge of the lumbar paraspinal muscle spindles increased in a curvilinear fashion. A concave up inflection occurred near the 100ms duration eliciting both a higher frequency discharge compared to the longer durations and a substantially faster rate of change as thrust duration was shortened. This pattern was evident in paraspinal afferents with receptive fields both close and far from the midline. Paradoxically, spindle afferents were almost twice as sensitive to the 1mm compared to the 2mm amplitude thrust (6.2 vs 3.3 spikes/s/mm/s). This latter finding may be related to the small vs large signal range properties of muscle spindles.
Conclusions
. The results indicate that the duration and amplitude of a spinal manipulation elicits a pattern of discharge from paraspinal muscle spindles different from slower mechanical inputs. Clinically, these parameters may be important determinants of an HVLA-SM's therapeutic benefit.
doi:10.1016/j.spinee.2006.10.006
PMCID: PMC2075482  PMID: 17905321
lumbar spine; spinal manipulation; chiropractic; osteopathy; paraspinal muscles; muscle spindle
22.  Clinical application of the paraspinal erector approach for spinal canal decompression in upper lumber burst fractures 
Objective
Percutaneous pedicle screw fixation is commonly used for upper lumber burst fractures. The direct decompression remains challenging with this minimally invasive surgery. The objective was to evaluate a novel paraspinal erector approach for effective and direct decompression in patients with canal compromise and neurologic deficit.
Method
Patients (n = 21) with neurological deficiency and Denis B type upper lumbar burst fracture were enrolled in the study, including 14 cases in the L1 and 7 cases in the L2. The patients underwent removal of bone fragments from the spinal canal through intervertebral foramen followed by short-segment fixation. Evaluations included surgery-related, such as duration of surgery and blood loss, and 12-month follow-up, such as the kyphotic angle, the height ratio of the anterior edge of the vertebra, the ratio of sagittal canal compromise, visual analog scale (VAS), Oswestry Disability Index (ODI), and Frankel scores.
Results
All patients achieved direct spinal canal decompression using the paraspinal erector approach followed by percutaneous pedicle screw fixation. The mean operation time (SD) was 173 (23) min, and the mean (SD) blood loss was 301 (104) ml. Significant improvement was noted in the kyphotic angle, 26.2 ± 8.7 prior to operation versus 9.1 ± 4.7 at 12 months after operation (p <0.05); the height ratio of the anterior edge of the injured vertebra, 60 ± 16% versus 84 ± 9% (p <0.05); and the ratio of sagittal canal compromise, 46.5 ± 11.4% versus 4.3 ± 3.6% (p <0.05). Significant improvements in VAS (7.3 ± 1.2 vs. 1.9 ± 0.7, p <0.05), ODI (86.7 ± 5.8 vs. 16.7 ± 5.1, p <0.05), and Frankel scores were also noted.
Conclusions
The paraspinal erector approach was effective for direct spinal canal decompression with minimal injury in the paraspinal muscles or spine. Significant improvements in spinal function and prognostics were achieved after the percutaneous pedicle screw fixation.
doi:10.1186/s13018-014-0105-4
PMCID: PMC4240844  PMID: 25387608
Erector spinae; Direct spinal canal decompression; Minimally invasive spine surgery; Surgical approach; Upper lumber burst fractures
23.  Lumbar magnetic resonance imaging hypolordosis in symptomatic patients: association with paraspinal muscle spasms☆ 
Abstract
Objective
This study examined a set of patients who were symptomatic for low back pain and who had significant lumbar hypolordosis as assessed by visual evaluation of magnetic resonance images to investigate the frequency of comorbid paraspinal muscle spasms as determined via history or physical examination.
Methods
A retrospective chart review was performed on 50 patients who had significant hypolordosis on magnetic resonance imaging (MRI) (Cobb angle <20°) to determine whether they were positive for paraspinal muscle spasms by either history or physical examination.
Results
Of the 50 patients with significant hypolordosis on MRI, 66% (33) had a history of paraspinal muscle spasms, 76% (38) had a positive physical examination for palpation of paraspinal muscle spasms, and 48% (24) were positive for both history and physical examination.
Conclusions
This retrospective study suggests that most symptomatic patients with significant hypolordosis on lumbar MRI have a positive history or physical examination for paraspinal muscle spasm. Thus, MRI finding of significant hypolordosis (Cobb angle <20°) could potentially be a valuable tool in addition to medical history and physical examination in aiding clinicians in diagnosing paraspinal muscle spasms in symptomatic patients and in helping them to formulate appropriate and effective treatments.
doi:10.1016/j.jcm.2009.05.001
PMCID: PMC2732250  PMID: 19703664
Lordosis; Spinal curvatures; Spinal diseases; Magnetic resonance imaging; Spasm
24.  Contribution of Hamstring Fatigue to Quadriceps Inhibition Following Lumbar Extension Exercise 
The purpose of this study was to determine the contribution of hamstrings and quadriceps fatigue to quadriceps inhibition following lumbar extension exercise. Regression models were calculated consisting of the outcome variable: quadriceps inhibition and predictor variables: change in EMG median frequency in the quadriceps and hamstrings during lumbar fatiguing exercise. Twenty-five subjects with a history of low back pain were matched by gender, height and mass to 25 healthy controls. Subjects performed two sets of fatiguing isometric lumbar extension exercise until mild (set 1) and moderate (set 2) fatigue of the lumbar paraspinals. Quadriceps and hamstring EMG median frequency were measured while subjects performed fatiguing exercise. A burst of electrical stimuli was superimposed while subjects performed an isometric maximal quadriceps contraction to estimate quadriceps inhibition after each exercise set. Results indicate the change in hamstring median frequency explained variance in quadriceps inhibition following the exercise sets in the history of low back pain group only. Change in quadriceps median frequency explained variance in quadriceps inhibition following the first exercise set in the control group only. In conclusion, persons with a history of low back pain whose quadriceps become inhibited following lumbar paraspinal exercise may be adapting to the fatigue by using their hamstring muscles more than controls.
Key PointsA neuromuscular relationship between the lumbar paraspinals and quadriceps while performing lumbar extension exercise may be influenced by hamstring muscle fatigue.QI following lumbar extension exercise in persons with a history of LBP group may involve significant contribution from the hamstring muscle group.More hamstring muscle contribution may be a necessary adaptation in the history of LBP group due to weaker and more fatigable lumbar extensors.
PMCID: PMC3818676  PMID: 24198683
Superimposed burst technique; electromyography; spectral median frequency; correlation and regression; low back pain
25.  Anterior Dislodgement of a Fusion Cage after Transforaminal Lumbar Interbody Fusion for the Treatment of Isthmic Spondylolisthesis 
Transforaminal lumbar interbody fusion (TLIF) is commonly used procedure for spinal fusion. However, there are no reports describing anterior cage dislodgement after surgery. This report is a rare case of anterior dislodgement of fusion cage after TLIF for the treatment of isthmic spondylolisthesis with lumbosacral transitional vertebra (LSTV). A 51-year-old man underwent TLIF at L4-5 with posterior instrumentation for the treatment of grade 1 isthmic spondylolisthesis with LSTV. At 7 weeks postoperatively, imaging studies demonstrated that banana-shaped cage migrated anteriorly and anterolisthesis recurred at the index level with pseudoarthrosis. The cage was removed and exchanged by new cage through anterior approach, and screws were replaced with larger size ones and cement augmentation was added. At postoperative 2 days of revision surgery, computed tomography (CT) showed fracture on lateral pedicle and body wall of L5 vertebra. He underwent surgery again for paraspinal decompression at L4-5 and extension of instrumentation to S1 vertebra. His back and leg pains improved significantly after final revision surgery and symptom relief was maintained during follow-up period. At 6 months follow-up, CT images showed solid fusion at L4-5 level. Careful cage selection for TLIF must be done for treatment of spondylolisthesis accompanied with deformed LSTV, especially when reduction will be attempted. Banana-shaped cage should be positioned anteriorly, but anterior dislodgement of cage and reduction failure may occur in case of a highly unstable spine. Revision surgery for the treatment of an anteriorly dislodged cage may be effectively performed using an anterior approach.
doi:10.3340/jkns.2013.54.2.128
PMCID: PMC3809439  PMID: 24175028
Cage; Transforaminal lumbar interbody fusion; Spondylolisthesis; Lumbosacral spine; Transitional vertebra

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