Sequential Depth Stimulation Within the Psoas Offers No Benefit for Localization of the Lumbar Plexus During Lateral Lumbar Fusion Surgery

STUDY DESIGN

Prospective cohort study.

OBJECTIVES

In this study we aim to assess the difference in triggered EMG readings throughout different depths in the psoas muscle during the lateral approach to the lumbar spine and their effect on surgeon decision making.

METHODS

Three surgeons, practicing at different institutions, assessed triggered EMG readings during the trans psoas approach at the level of the disc and 5,10 and 15 millimeters into the psoas muscle with sequential dilators. Measurement of distance into the psoas muscle was done with a specially designed instrument. Results of anterior and posterior directed stimulation as well as the delta value between these were recorded and underwent statistical analysis. Patients who had partial readings were excluded from the study.

RESULTS

A total of 40 levels in 35 patients were included in the study. There was no significant difference found between means of anterior or posterior threshold readings along the different distance groups. A significant difference was found (P = .024) in the mean difference between the distance groups with a decrease in the difference between anterior and posterior threshold values found as the distance from the disc space increased. None of the surgeons reported a decision to abort the fusion of a spinal level.

CONCLUSIONS

In the trans-psoas approach to the lumbar spine, the assessment of the location of the femoral nerve using directional neuromonitoring when advancing in the psoas muscle shows no clear benefit as opposed to stimulating solely when adjacent to the disc space.

Impact of Frailty in Patients Undergoing Minimally Invasive Mitral Valve Surgery

OBJECTIVE

Psoas muscle size is a reliable marker of sarcopenia and frailty that correlates with adverse outcomes after cardiac surgery. However, its use in mitral and minimally invasive cardiac surgery is lacking. We sought to determine whether frailty, as measured by psoas muscle index, increases surgical risk for minimally invasive mitral valve surgery.

METHODS

Patients undergoing isolated minimally invasive mitral surgery via right minithoracotomy were identified. Patients who underwent maze, tricuspid intervention, and those who were emergent were excluded. Total psoas muscle area was calculated using the average cross-sectional area at the L3 vertebra on computed tomography scan and indexed to body surface area. Sarcopenia was defined as <25th gender-specific percentile. Patients were stratified by sarcopenia status and outcomes compared.

RESULTS

Of 287 total patients, 192 patients met inclusion criteria. Sarcopenic patients were 6 years older (66 vs 60 years, P = 0.01), had lower preoperative albumin levels (4.0 vs 4.3 g/dL, P < 0.001), and had higher Society of Thoracic Surgeons risk of morbidity/mortality (13.1% vs 9.0%, P = 0.003). Operative major morbidity or mortality was 6.4% versus 5.5% (P = 0.824), while the 1-year mortality rate was 2.1% versus 0% (P = 0.08). After risk adjustment, psoas index did not predict operative morbidity or mortality. However, sarcopenia was associated with higher odds of readmission (odds ratio = 0.74, P = 0.02).

CONCLUSIONS

Contrary to other cardiac operations, for patients undergoing isolated minimally invasive mitral valve surgery, sarcopenia was not associated with increased perioperative risk except for higher readmission rates. Minimally invasive surgical approaches should be strongly considered as the approach of choice in frail patients.

Utilizing psoas muscle cross-sectional area to predict functional outcome

Background

This study evaluated psoas muscle area (PMA) as a predictor of frailty and functional outcome in trauma patients.

Methods

The cohort included 211 trauma patients admitted to an urban level I trauma center from March 2012 to May 2014 who consented to participate in a longitudinal study and underwent abdominal-pelvic computed tomography scans during their initial evaluation. Physical component scores (PCS) of the Veterans RAND 12-Item Health Survey were administered to assess physical functionality at baseline and at 3, 6, and 12 months after injury. PMA in mm² and Hounsfield units was calculated using the Centricity PACS system. Statistical models were stratified by injury severity score (ISS), <15 or ≥15, and adjusted for age, sex, and baseline PCS. Follow-up PCS were analyzed using general linear regression models.

Results

For participants with an ISS <15, increased PMA was significantly associated with higher PCS at 3 (P = 0.008), 6 (P = 0.02), and 12 months (P = 0.002), although this relationship was not statistically significant for ISS ≥15 (P = 0.85, 0.66, 0.61).

Conclusion

For mild to moderately injured (but not seriously injured) patients, those with larger psoas muscles experience better functional outcomes after injury.

Early Clinical Outcomes of the Prone Transpsoas Lumbar Interbody Fusion Technique

BACKGROUND

The prone transpsoas (PTP) approach for lateral lumbar interbody fusion (LLIF) is a relatively novel technique. Currently, little is known about its associated complications and early patient-reported outcomes. The aim of this study was to investigate the effect of LLIF performed via the PTP approach on sagittal radiographic parameters, patient-reported outcome measures (PROMs), and rates of complications.

METHODS

A retrospective review was performed of 82 consecutive patients who underwent LLIF via a PTP technique. Lumbar lordosis (LL), segmental lordosis (SL), anterior disc height (ADH), and posterior disc height (PDH) were measured on preoperative, initial postoperative, and 3-month postoperative radiographs. PROMs including the Oswestry Disability Index (ODI); the visual analog scale (VAS); and pain portions of the EQ5D, VAS back, and VAS leg ratings were collected at the preoperative and subsequent postoperative visits. Length of hospital stay and postoperative complications related to the procedure were recorded.

RESULTS

Significant improvements were seen at the initial (4.5° ± 8.6°, P < 0.001) and 3-month (4.4° ± 7.2°, P < 0.001) postoperative periods for LL, as well as SL (6.8° ± 4.8°, P < 0.001; 6.7° ± 4.4°, P < 0.001), ADH (8.0 mm ± 3.6, P < 0.001; 7.4 mm ± 3.6, P < 0.001), and PDH (3.3 mm ± 2.4, P < 0.001; 3.1 mm ± 2.5, P < 0.001). Significant improvements were seen at 3 months postoperatively for ODI (P < 0.001), EQ5D pain (P = 0.016), VAS leg (P < 0.001), and VAS back (P < 0.001). The average length of stay was 2.7 ± 4.5 days. The most common complications were ipsilateral thigh pain/numbness (45.1%), ipsilateral hip flexor weakness (39.0%), and contralateral thigh pain/numbness (14.6%).

CONCLUSIONS

While early PROMs and correction of sagittal radiographic parameters show promising results for the PTP approach for LLIF, it is not without risks.

CLINICAL RELEVANCE

PTP interbody fusion is an emerging technique that allows for simultaneous access to the anterior and posterior columns of the lumbar spine. This early case series demonstrates significant improvement in functional outcomes and lumbar lordosis with a safety profile comparable to other well-established techniques.

LEVEL OF EVIDENCE: 3

Psoas and Mediastinal Abscesses during Intravenous Tocilizumab Treatment in Multicentric Castleman Disease

Tocilizumab has been used to treat idiopathic multicentric Castleman disease (iMCD). As tocilizumab prevents interleukin-6 from exerting pro-inflammatory effects, there is some concern about a delayed diagnosis of severe infections during tocilizumab treatment. Although serious infections during tocilizumab therapy have been previously described in patients with rheumatoid arthritis, they have not been reported in iMCD. We herein report a case of disseminated Staphylococcus aureus infection after a superficial skin wound followed by psoas and mediastinal abscesses with pyogenic spondylodiscitis in an iMCD patient with diabetes. Physicians should be alert for the occurrence of disseminated S. aureus infection after even minor skin injury during tocilizumab therapy.

A modified oblique lumbar interbody fusion: A better way to establish an exposure under direct microscopic vision

Study design

This is a retrospective study.

Objective

To demonstrate a modified oblique lumbar interbody fusion (OILF) technique for L1-L5.

Methods

The modified technique splits anterior portion of psoas belly to access the oblique corridor (OC) anteroinferior to psoas, minimizing psoas manipulation and retraction and avoiding nerve injury while offering excellent microscopic visualization. Psoas weakness and neurovascular complication rates in patients treated with traditional OLIF (T-OLIF) or anteroinferior psoas OLIF (AP-OLIF) were retrospectively reviewed. Clinical outcomes were also reviewed.

Results

A total of 162 cases treated with T-OLIF (n = 73) and AP-OLIF (n = 89) for degenerative lumbar disease were included. The mean operative time and blood loss were less with AP-OLIF (P < 0.01). Approach related complications were 14 (19.1%) with T-OLIF and 4 (4.5%) with AP-OLIF. Postoperative visual analog scale (VAS) and Oswestry Disability Index (ODI) scores improved in both T-OIF and AP-OIF groups (P < 0.01).

Conclusion

The modified OLIF technique (AP-OLIF) is characterized by an easy exposure of the lumbar spine under direct microscopic vision, resulting in less psoas weakness and neurovascular injury.

Does Unilateral Lumbosacral Radiculopathy Affect the Association between Lumbar Spinal Muscle Morphometry and Bone Mineral Density?

Age-related degenerative changes lead to a gradual decrease in bone mineral density (BMD) and muscle mass. We aimed to assess the effects of decreased BMD and lumbar denervation on lumbar spinal muscle morphometry and the relationship between BMD and lumbar spinal muscular morphometry, respectively. Eighty-one patients, aged 50–85 years, diagnosed with unilateral lumbosacral radiculopathy based on electrodiagnostic studies between January 2016 and April 2021 were enrolled. BMD T scores in the lumbar spine and hip were measured using dual-energy X-ray absorptiometry. The cross-sectional area (CSA) of the psoas, multifidus, and erector spinae located in the middle of the lumbar spine, between the L3 and L4 and between the L4 and L5 levels, respectively, was measured using axial MRI. Functional CSA (FCSA) was defined as the CSA of lean muscle mass. Pearson correlation analyses were performed to evaluate the association between BMD T scores and the CSA, FCSA, and the ratio of the FCSA to the CSA (functional ratio) for each side. The CSA of lumbar spinal muscles showed no significant correlation with lumbar BMD. The FCSA and functional ratio of lumbar spinal muscles were significantly correlated with lumbar BMD. There was no correlation between femur BMD and lumbar spinal muscle morphometry.

Solitary Cystic Psoas Muscle Metastasis From Rectosigmoid Adenocarcinoma

The most common subtype of colon cancer is colorectal adenocarcinoma. Compared with other subtypes, such as signet-ring and mucinous, colorectal adenocarcinoma has been found to have lower rates of metastasis. Approximately 20% of colorectal cancer cases present with metastatic disease on initial evaluation. The most common locations for metastasis are the liver, lung, peritoneum, bone, and extra-regional lymph nodes. Metastatic disease to the skeletal muscle, however, is considerably rare. We present a clinical case of a 52-year-old female found to have a cystic iliopsoas muscle metastasis from rectosigmoid adenocarcinoma, initially classified as an infected fluid collection.

Reciprocal relationship between multifidus and psoas at L4-L5 level in women with low back pain

Background Low back pain (LBP) may originate from different sources such as intervertebral disc degeneration (IVDD), end-plate and paraspinal muscle changes. Our aim is to explore the relevance of paraspinal muscles' fat-infiltration in women with LBP and its association with IVDD and Modic changes.Methods Consecutive female patients presenting with chronic LBP to the outpatient clinics were included. Patients were evaluated in terms of IVDD, vertebral end-plate changes, and fatty infiltration in the paraspinal muscles at all lumbar levels on lumbar spine magnetic resonance imaging (MRI). Visual Analogue Scale (VAS) scores were recorded using our prospectively collected database.Results Patients with higher VAS scores were significantly more likely to have more fatty infiltration in the multifidus and less fatty infiltration in the psoas at L4-L5 level when compared to those with lower VAS scores (69.1 vs. 31.8%, p = 0.003). To predict LBP, fatty infiltration in the multifidus and psoas had odds ratio (OR) of 4 (p = 0.010), and 0.3 (p = 0.013), respectively; whereas disc degeneration had an OR of 0.5 (p = 0.028).Conclusion This is the first clinical cross-sectional study suggested that women with chronic low back pain could have less fat-infiltrated psoas to compensate more fat-infiltrated multifidus at L4-L5 disc level.

Exploring the Clinical Response of Childhood Functional Gastro-Intestinal Disorder Symptoms to Deep Tissue Massage of Psoas Muscles: Results of Two-Year Clinical Audit with Telephone Follow-Up

BACKGROUND & PURPOSE

There is a high incidence of chronic recurrent functional abdominal pain in children causing significant disruption to schooling, quality of life, and costs to the health care system. Treatment routinely includes behavioral, pharmacological, and invasive surgical interventions, with varying levels of impact. This study aims to examine the response of symptoms of functional gastro-intestinal disorders (FGID) in children to treatment of psoas muscle tension and tenderness using remedial massage therapy.

SETTING & PARTICIPANTS

Pediatric surgeon's rooms, remedial massage therapist rooms, consenting children aged 2-18.

RESEARCH DESIGN

Two years of clinical observations were analyzed including patient-reported symptoms, surgeon and remedial massage therapist observations, with 122 children suffering from moderate to severe FGID symptoms. Over the two year observation period, 96 children with FGID symptoms completed a course of remedial massage therapy to their psoas muscles.

RESULTS

Improvement in psoas tension and tenderness on palpation was observed for all participants after an average of 5 treatments (range 2-12). Complete resolution of all symptoms of abdominal pain, reflux, vomiting, nausea, and bowel upset was seen in 88/96 (92%) participants at the time of treatment completion without side effects. Over the observation period, 72 children were followed up after completing remedial massage therapy; 75% reported they remained symptom free, 18% continued to have marked improvement and 7% mild improvement.

CONCLUSION

Despite study design limitations, more research is warranted on the potential for this low-cost, noninvasive therapeutic intervention to assist symptom management for children with FGID.

Acute Appendicitis: Clinical Clues and Conundrums Related to the Greatest Misses

Introduction

In the United States (US), appendicitis is the most common acute abdominal emergency requiring surgery. Patients with appendicitis continue to display a complex and atypical range of clinical manifestations, providing a subsequent high risk for emergency physicians to miss acute abdominal pathology on a patient’s initial visits. Due to the risk of potential perforation, the proper and timely clinical identification of acute appendicitis is vital. The current study aims to identify clinical characteristics that could be useful in identifying patients at risk for having acute appendicitis that was misdiagnosed on their initial visits.

Methods

Medical charts consisting of patients between the ages of 19 and 55 years on their second visit were flagged and reviewed by the emergency department quality assurance (EDQA) committee. The retrospective chart review included patients who presented to the emergency department (ED) with the chief complaint of an abdominal-related complaint, were discharged, returned within 72 hours, and were diagnosed with a pathologically confirmed appendicitis. All patients were managed operatively, with pathology results reviewed for evidence of acute appendicitis. Those with confirmed pathologic appendicitis upon return were considered to have a “misdiagnosis.” Any patients managed nonoperatively and those with negative pathology were excluded from the study and considered not to have appendicitis.

Results

Fifty-five patients were identified through the EDQA committee from May 2011 to January 2014. After exclusion criteria were applied, 18 patients met the inclusion criteria for this study (7 males, 11 females). The mean age was 36.2 (range: 19-55). The most common presenting complaint on the initial visit was pain in the epigastric region of the abdomen (50%, n = 9). Twenty-two percent (n = 4) of patients had pain in the right lower quadrant documented in the physician’s note on the initial visit and 83% (n = 15) had right lower quadrant pain documented on the second visit. Two patients (11%) did not have right lower quadrant tenderness on either visit. The most common discharge diagnosis on the initial visit was undifferentiated abdominal pain (50%), followed by gastritis (28%). Opioid pain medication was administered or prescribed to 39% (n = 7) of the patients. The average return time was 23.9 hours.

Conclusion

The administration of opioid pain medication is associated with many of the return visits to the emergency department for missed appendicitis. Finally, discharge diagnosis and planning are imperative, as detailed early appendicitis instructions or extended ED observation can include more cases and decrease litigation risk.

The value of different CT-based methods for diagnosing low muscle mass and predicting mortality in patients with cirrhosis

BACKGROUND & AIMS

Low muscle mass impacts on morbidity and mortality in cirrhosis. The skeletal-muscle index (SMI) is a well-validated tool to diagnose muscle wasting, but requires specialized radiologic software and expertise. Thus, we compared different Computed tomography (CT)-based evaluation methods for muscle wasting and their prognostic value in cirrhosis.

METHODS

Consecutive cirrhotic patients included in a prospective registry undergoing abdominal CT scans were analysed. SMI, transversal psoas muscle thickness (TPMT), total psoas volume (TPV) and paraspinal muscle index (PSMI) were measured. Sarcopenia was defined using SMI as a reference method by applying sex-specific cut-offs (males: <52.4 cm² /m² ; females: <38.5 cm² /m² ).

RESULTS

One hundred and nine patients (71.6% male) of age 57 ± 11 years, MELD 16 (8-26) and alcoholic liver disease (63.3%) as the main aetiology were included. According to established SMI cut-offs, low muscle mass was present in 69 patients (63.3%) who also presented with higher MELD (17 vs 14 points; P = .025). The following optimal sex-specific cut-offs (men/women) for diagnosing low muscle mass were determined: TPMT: <10.7/ <7.8 mm/m, TPV: <194.9/ <99.2 cm³ and PSMI <26.3/ <20.8 cm² /m² . Thirty (27.5%) patients died during a follow-up of 15 (0.3-45.7) months. Univariate competing risks analyses showed a significant risk for mortality according to SMI (aSHR:2.52, 95% CI: 1.03-6.21, P = .043), TPMT (aSHR: 3.87, 95% CI: 1.4-8.09, P = .007) and PSMI (aSHR: 2.7, 95% CI: 1.17-6.23, P = .02), but not TPV (P = .18) derived low muscle mass cut-offs. In multivariate analysis only TPMT (aSHR: 2.82, 95% CI: 1.20-6.67, P = .018) was associated with mortality, SMI (aSHR: 1.93, 95% CI: 0.72-5.16, P = .19) and PSMI (aSHR: 1.93, 95% CI: 0.79-4.75, P = .15) were not.

CONCLUSION

Low muscle mass was highly prevalent in our cohort of patients with cirrhosis. Gender-specific TPMT, SMI and PSMI cut-offs for low muscle mass can help identify patients with an increased risk for mortality. Importantly, only TPMT emerged as an independent risk factor for mortality in patients with cirrhosis.

Severe Lumbar Disability Is Associated With Decreased Psoas Cross-Sectional Area in Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort.

OBJECTIVES

Alterations in lumbar paraspinal muscle cross-sectional area (CSA) may correlate with lumbar pathology. The purpose of this study was to compare paraspinal CSA in patients with degenerative spondylolisthesis and severe lumbar disability to those with mild or moderate lumbar disability, as determined by the Oswestry Disability Index (ODI).

METHODS

We retrospectively reviewed the medical records of 101 patients undergoing lumbar fusion for degenerative spondylolisthesis. Patients were divided into ODI score ≤40 (mild/moderate disability, MMD) and ODI score >40 (severe disability, SD) groups. The total CSA of the psoas and paraspinal muscles were measured on preoperative magnetic resonance imaging (MRI).

RESULTS

There were 37 patients in the SD group and 64 in the MMD group. Average age and body mass index were similar between groups. For the paraspinal muscles, we were unable to demonstrate any significant differences in total CSA between the groups. Psoas muscle CSA was significantly decreased in the SD group compared with the MMD group (1010.08 vs 1178.6 mm², P = .041). Multivariate analysis found that psoas CSA in the upper quartile was significantly protective against severe disability (P = .013).

CONCLUSIONS

We found that patients with severe lumbar disability had no significant differences in posterior lumbar paraspinal CSA when compared with those with mild/moderate disability. However, severely disabled patients had significantly decreased psoas CSA, and larger psoas CSA was strongly protective against severe disability, suggestive of a potential association with psoas atrophy and worsening severity of lumbar pathology.

Relationships of Vancomycin Pharmacokinetics to Body Size and Composition Using a Novel Pharmacomorphomic Approach Based on Medical Imaging

Antibiotics such as vancomycin are empirically dosed on the basis of body weight, which may not be optimal across the expanding adult body size distribution. Our aim was to compare the relationships between morphomic parameters generated from computed tomography images to conventional body size metrics as predictors of vancomycin pharmacokinetics (PK). This single-center retrospective study included 300 patients with 1,622 vancomycin concentration (52% trough) measurements. Bayesian estimation was used to compute individual vancomycin volume of distribution of the central compartment (Vc) and clearance (CL). Approximately 45% of patients were obese with an overall median (5th, 95th percentile) weight and body mass index of 87.2 (54.7, 123) kg and 28.8 (18.9, 43.7) kg/m², respectively. Morphomic parameters of body size such as body depth, total body area, and torso volume of the twelfth thoracic through fourth lumbar vertebrae (T12 to L4) correlated with Vc. The relationship of vancomycin Vc was poorly predicted by body size but was stronger with T12-to-L4 torso volume (coefficient of determination [R²] = 0.11) than weight (R² = 0.04). No relationships between vancomycin CL and traditional body size metrics could be discerned; however, relationships with skeletal muscle volume and total psoas area were found. Vancomycin CL independently correlated with total psoas area and inversely correlated with age. Thus, vancomycin CL was significantly related to total psoas area over age (R² = 0.23, P < 0.0001). This proof-of-concept study suggests a potential role for translation of radiographic information into parameters predictive of drug pharmacokinetics. Prediction of individual antimicrobial pharmacokinetic parameters using analytic morphomics has the potential to improve antimicrobial dose selection and outcomes of obese patients.

Primary psoas sarcoma causing malignant psoas syndrome: favourable response to radiotherapy

Malignant psoas syndrome (MPS) is an uncommon condition first described by Stevens et al. MPS is caused by malignant infiltration of the psoas muscle and adjacent nerves and is characterised by (fixed) flexion deformity of the ipsilateral hip and proximal lumbosacral plexopathy. It has previously been described in relation to metastatic carcinoma, melanoma and liposarcoma, as well as non-Hodgkins lymphoma. We present the case of a 68-year-old woman with a sarcoma arising in the left psoas muscle at the level of L4 who presented with symptoms of MPS. To the authors' knowledge this is the first case of MPS arising from a primary sarcoma of the iliopsoas compartment. The patient underwent presurgical radiotherapy, with a significant improvement in pain control without an increase in analgesic medications. We discuss the aetiology of MPS and the role of radiotherapy in the treatment of this rare syndrome.

[Hydatid cyst of the psoas muscle: about a case]

Le muscle psoas est une localisation exceptionnelle du kyste hydatique. Le but de cette lettre est de rapporter l'observation d'un kyste hydatique localisé au niveau du muscle psoas gauche chez un patient âgé de 32 ans. L'échographie, la tomodensitométrie ainsi qu'une sérologie hydatique positive ont contribué au diagnostic préopératoire. Le patient a été opéré par incision para rectale gauche type Jalaguier. L'examen microscopique du culot de centrifugation du liquide hydatique a mis en évidence des scolex et de nombreux crochets confirmant ainsi le diagnostic. L'évolution était bonne sans récidive après le traitement chirurgical.

Non-small cell lung cancer with concomitant intramuscular myxoma of the right psoas mimicking intramuscular metastasis: A case report and literature review

Intramuscular myxoma (IMM) as a rare soft-tissue tumor arising from the muscles is completely benign. When IMM accompanies malignance, it may be misdiagnosed as muscle metastasis, and for this extremely rare concurrence, the subsequent treatment would vary accordingly. The current study presents, to the best of our knowledge, the first case of non-small cell lung cancer (NSCLC) concomitant with IMM mimicking skeletal muscle metastasis. A 64-year-old female was hospitalized with a history of chest discomfort and right lumbar pain that had persisted for four months. The computed tomography scan showed a lesion in the left upper lobe of the lung and the right psoas, respectively. Serum biomarkers for NSCLC were abnormal. A presumptive clinical diagnosis was compatible with left NSCLC and right psoas muscle metastasis (cT2aN3M1b, stage IV). Stage IV lung cancer would receive palliative treatment. However, the final diagnosis of synchronous left lung squamous cell carcinoma (cT2aN3M0, stage IIIB) and IMM in the right psoas was confirmed by biopsy. The patient therefore underwent definitive chemoradiotherapy for lung carcinoma, and conservative treatment, including analgesics, for IMM. The diagnosis process for a malignant neoplasm concomitant with IMM is not straightforward due to a lack of clinical experience, and it significantly affects the tumor staging and subsequent treatment strategy. The present case suggests that IMM should be included in the differential diagnosis when an abnormal intramuscular lesion concomitant with malignancy is identified. The value of histopathological diagnosis prior to definitive treatment also requires highlighting.

Relationship between psoas muscle dimensions and post operative thigh pain. A possible preoperative evaluation factor

INTRODUCTION

Advanced intraoperative neuromonitoring (IONM) is used to attenuate postoperative complications and side effects of extreme lateral interbody fusion (XLIF). Specific factors relate to the presence of postoperative injury are not well understood. This study aims to identify intraoperative variables with correlations to new postoperative anterior thigh/groin sensory changes.

METHODS

Twenty-nine patients with various degenerative lumbar conditions were treated with XLIF at a single institution. Mean age was 59 years, 69% were female, and 21% had undergone previous lumbar surgery. A total of 47 levels (mean 1.6, range 1-3) were treated with XLIF. Supplemental pedicle screw and rod fixation was used in 24 patients (83%). Dynamically-evoked electromyography was used in all cases. Analysis of baseline demographic and treatment variables were performed at a per patient basis (n = 29), whereas analysis of intraoperative variables were performed at a per levels treated basis (n = 47).

RESULTS

Within 24 hours postoperative, 10 (34%) patients experienced anterior thigh/groin sensory changes (4 reported pain only, 5 reported pain plus other sensory changes, and 1 paresthesia without pain). Symptom resolution occurred at 1 month postoperative for 4 patients, at 3 months postoperative for 2 patients. At 3 months postoperative, 6 patients had complete symptom resolution, 3 patients had symptom improvements, and 1 patient had no change in perioperative symptoms. Psoas dimension in the lateral-latero direction were significantly smaller for patients with postoperative sensory changes (p = 0.025), and similarly, patients with postoperative sensory changes had a significantly higher ratio of psoas muscle in the anterior-posterior to lateral-latero directions (p = 0.026).

CONCLUSIONS

In addition to IONM, MRI evaluation of psoas shape, position, and dimension may be of help in preoperative planning of a safe XLIF access and eventually, predict those cases with higher risk of approach-related post-operative events.

Retroperitoneal oblique corridor to the L2-S1 intervertebral discs in the lateral position: an anatomic study

OBJECT

Access to the intervertebral discs from L2-S1 in one surgical position can be challenging. The transpsoas minimally invasive surgical (MIS) approach is preferred by many surgeons, but this approach poses potential risk to neural structures of the lumbar plexus as they course through the psoas. The lumbar plexus and iliac crest often restrict the L4-5 disc access, and the L5-S1 level has not been a viable option from a direct lateral approach. The purpose of the present study was to investigate an MIS oblique corridor to the L2-S1 intervertebral disc space in cadaveric specimens while keeping the specimens in a lateral decubitus position with minimal disruption of the psoas and lumbar plexus.

METHODS

Twenty fresh-frozen full-torso cadaveric specimens were dissected, and an oblique anatomical corridor to access the L2-S1 discs was examined. Measurements were taken in a static state and with mild retraction of the psoas. The access corridor was defined at L2-5 as the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5-S1 corridor of access was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel and vertically to the first vascular structure that crosses midline.

RESULTS

The mean access corridor diameters in the static state and with mild psoas retraction, respectively, were as follows: at L2-3, 18.60 mm and 25.50 mm; at L3-4, 19.25 mm and 27.05 mm; and at L4-5, 15.00 mm and 24.45 mm. The L5-S1 corridor mean values were 14.75 mm transversely, from midline to the left common iliac vessel and 23.85 mm from the inferior endplate of L-5 cephalad to the first midline vessel.

CONCLUSIONS

The oblique corridor allows access to the L2-S1 discs while keeping the patient in a lateral decubitus position without a break in the table. Minimal psoas retraction without significant tendon disruption allowed for a generous corridor to the disc space. The L5-S1 disc space can be accessed from an oblique angle consistently with gentle retraction of the iliac vessels. This study supports the potential of an MIS oblique retroperitoneal approach to the L2-S1 discs.

Outcome of percutaneous continuous drainage of psoas abscess: A clinically guided technique

BACKGROUND

Percutaneous aspiration of abscesses under ultrasonography (USG) and computer tomography (CT) scan has been well described. With recurrence rate reported as high as 66%. The open drainage and percutaneous continuous drainage (PCD) has reduced the recurrence rate. The disadvantage of PCD under CT is radiation hazard and problems of asepsis. Hence a technique of clinically guided percutaneous continuous drainage of the psoas abscess without real-time imaging overcomes these problems. We describe clinically guided PCD of psoas abscess and its outcome.

MATERIALS AND METHODS

Twenty-nine patients with dorsolumbar spondylodiscitis without gross neural deficit with psoas abscess of size >5 cm were selected for PCD. It was done as a day care procedure under local anesthesia. Sequentially, aspiration followed by guide pin-guided trocar and catheter insertion was done without image guidance. Culture sensitivity was done and chemotherapy initiated and catheter kept till the drainage was <10 ml for 48 hours. Outcome assessment was done with relief of pain, successful abscess drainage and ODI (Oswestry Disability Index) score at 2 years.

RESULTS

PCD was successful in all cases. Back and radicular pain improved in all cases. Average procedure time was 24.30 minutes, drain output was 234.40 ml, and the drainage duration was 7.90 days. One patient required surgical stabilisation due to progression of the spondylodiscitis resulting in instability inspite of successful drainage of abscess. Problems with the procedure were noticed in six patients. Multiple attempts (n = 2), persistent discharge (n = 1) for 2 weeks, blocked catheter (n = 2) and catheter pull out (n = 1) occurred with no effect on the outcome. The average ODI score improved from 62.47 to 5.51 at 2 years.

CONCLUSIONS

Clinically guided PCD is an efficient, safe and easy procedure in drainage of psoas abscess.

Accepted Common Interest Community (CIC) Proposals

These are the 18 accepted proposals for the three Common Interest Community (CIC) sessions at IAYT's Symposium on Yoga Therapy and Research (SYTAR), June 5-8, 2014, in Austin, Texas and published in the Final Program Guide and CIC Works for SYTAR 2014. The sessions were CIC#1 Rehab Professionals: Bridging the Past with the Future and CIC#2a & CIC#2b Mental, Emotional and Spiritual Health.

Bilateral psoas and bilateral perinephric abscesses complicating acute pyelonephritis in pregnancy

Acute pyelonephritis complicates 1-2% of pregnancies and causes significant maternal and fetal morbidity and mortality. The diagnosis of renal tuberculosis (TB) is often delayed and commonly presents with sterile pyuria or along with other pyogenic organisms. We report a case where the diagnosis of renal TB was missed in a pregnant woman when she presented with acute pyelonephritis, septic shock, and acute renal failure. There was clinical recovery with antibiotics, but bilateral psoas and perinephric abscesses (TB, Enterococcus sp., and E. coli) were diagnosed when she presented with loin pain and palpable left renal angle swelling. Bilateral psoas abscess due to TB in the absence of skeletal TB and human immunodeficiency virus infection is rare. The presentation of renal TB in pregnancy, its complications, and its management are discussed.

The anteromedial approach to the psoas tendon in patients with cerebral palsy

PURPOSE

Release of the psoas tendon for flexion deformity of the hip in children with cerebral palsy has traditionally been performed at the pelvic brim, lateral to the neurovascular bundle, or at its insertion into the lesser trochanter. As the psoas tendon is lateral to the pectineus, the traditional exposure of the tendon through an approach medial to the pectineus is limited by the extent to which the pectineus can be retracted proximally.

TECHNICAL NOTE

We describe the use of the anteromedial approach used for the developmentally dislocated hip to expose the psoas tendon between the pectineus and the neurovascular bundle. This provides a much better visualisation of the tendon as it crosses the superior pubic ramus to its insertion. The use of this approach has not been described in cerebral palsy.

CT imaging of trunk muscles in chronic low back pain patients and healthy control subjects

Increasing documentation on the size and appearance of muscles in the lumbar spine of low back pain (LBP) patients is available in the literature. However, a comparative study between unoperated chronic low back pain (CLBP) patients and matched (age, gender, physical activity, height and weight) healthy controls with regard to muscle cross-sectional area (CSA) and the amount of fat deposits at different levels has never been undertaken. Moreover, since a recent focus in the physiotherapy management of patients with LBP has been the specific training of the stabilizing muscles, there is a need for quantifying and qualifying the multifidus. A comparative study between unoperated CLBP patients and matched control subjects was conducted. Twenty-three healthy volunteers and 32 patients were studied. The muscle and fat CSAs were derived from standard computed tomography (CT) images at three different levels, using computerized image analysis techniques. The muscles studied were: the total paraspinal muscle mass, the isolated multifidus and the psoas. The results showed that only the CSA of the multifidus and only at the lowest level (lower end-plate of L4) was found to be statistically smaller in LBP patients. As regards amount of fat, in none of the three studied muscles was a significant difference found between the two groups. An aetiological relationship between atrophy of the multifidus and the occurrence of LBP can not be ruled out as a possible explanation. Alternatively, atrophy may be the consequence of LBP: after the onset of pain and possible long-loop inhibition of the multifidus a combination of reflex inhibition and substitution patterns of the trunk muscles may work together and could cause a selective atrophy of the multifidus. Since this muscle is considered important for lumbar segmental stability, the phenomenon of atrophy may be a reason for the high recurrence rate of LBP.

The site of force generation in muscle contraction as deduced from fluorescence polarization studies

The fluorescent dye, N(-iodoacetylamino)-l-naphthylanine-5-sulfonic acid, labeled exclusively the myosin cross-bridges in rabbit glycerinated psoas muscle fibers, without impairing their function. Fluorescence polarization was used to study cross-bridge orientation in rigor, relaxation, and contraction, as a function of sarcomere length. At a length where no overlap between thick and thin filaments occurs, rigor-inducing, relaxation-inducing, and contraction-inducing solutions all induced the relaxation attitude. At lengths where overlap does exist, the slowly-hydrolyzing ATP analog, "alpha,beta-methylene ATP," induced the relaxation attitude. The data were consistent with the A. F. Huxley-Simmons model of force generation. Combined with our earlier results, the data indicated that torque was generated at the actin-myosin interface.

Individual states in the cycle of muscle contraction

By using appropriate analogs of ATP, isometrically-held glycerol-extracted psoas fibers from rabbits are forced successively into states corresponding to molecular species in the contractile cycle. In each state measurements are made of P[unk], a fluorescence polarization parameter thought to relate to attitude of S-1 moieties of the myosin molecules. Also, the value of P[unk] is measured during active tension development. It is suggested that this value is a time-average of the P[unk] as S-1 moieties move through the various states of the cycle. Proposals are made concerning the sequence of states in the cycle.