Lumbar Multifidus Intramuscular Fat Concentrations are Associated With Recovery Following Decompressive Surgery for Lumbar Spinal Stenosis

Spine 2026;51:25–33

This longitudinal cohort study investigates whether preoperative intramuscular fat (IMF) in lumbar paraspinal muscles predicts five-year recovery and surgical success after decompressive surgery for lumbar spinal stenosis causing intermittent neurogenic claudication. Using automated MRI segmentation and quantitative IMF thresholds, outcomes included global perceived effect, Zurich Claudication Questionnaire-based surgical success, pain VAS, and disability scores.

Key findings show lower preoperative multifidus IMF (but not erector spinae IMF) was associated with higher rates of perceived recovery, surgical success, and reduced long-term disability over five years. No consistent relationship was found between IMF and leg or back pain trajectories; results were adjusted for age, BMI, sex, smoking, reoperation, and surgical technique.

Lumbar multifidus intramuscular fat (IMF): Lower preoperative IMF in the lumbar multifidus muscle is associated with higher rates of perceived recovery and surgical success after decompression surgery for lumbar spinal stenosis (LSS) over a five-year period.

Erector spinae IMF: Preoperative IMF levels in the erector spinae muscle are not significantly associated with recovery or surgical success following LSS surgery.

Disability outcomes: Patients with nonsevere IMF in the right lumbar multifidus experience less postoperative disability for up to five years compared to those with severe IMF.

Pain outcomes: No significant association exists between preoperative paraspinal IMF (either muscle) and the clinical course of leg or back pain intensity after surgery.

IMF quantification method: Automated MRI-based quantification and categorization of IMF (<50% = nonsevere, ≥50% = severe) using computer vision models enables objective assessment of paraspinal muscle health.

Prognostic value: Assessing lumbar multifidus IMF preoperatively can improve prediction of which patients are at risk for poor recovery and help tailor individual interventions.

Study limitations: Missing data (up to 32% at five years), dichotomized IMF classification, and limited field-of-view for some muscles may affect precision; more detailed and larger studies are needed.

Clinical implication: Routine IMF assessment may enhance clinical decision-making and rehabilitation strategies for patients undergoing lumbar decompressive surgery.

Navigated transcranial magnetic stimulation for glioma removal- prognostic value in motor function recovery from postsurgical neurological deficits

J Neurosurg 127:877–891, 2017

The aim of the present study was to evaluate the usefulness of navigated transcranial magnetic stimulation (nTMS) as a prognostic predictor for upper-extremity motor functional recovery from postsurgical neurological deficits.

METHODS Preoperative and postoperative nTMS studies were prospectively applied in 14 patients (mean age 39 ± 12 years) who had intraparenchymal brain neoplasms located within or adjacent to the motor eloquent area in the cerebral hemisphere. Mapping by nTMS was done 3 times, i.e., before surgery, and 1 week and 3 weeks after surgery. To assess the response induced by nTMS, motor evoked potential (nTMS-MEP) was recorded using a surface electromyography electrode attached to the abductor pollicis brevis (APB). The cortical locations that elicited the largest electromyography response by nTMS were defined as hotspots. Hotspots for APB were confirmed as positive responsive sites by direct electrical stimulation (DES) during awake craniotomy. The distances between hotspots and lesions (DHS-L) were measured. Postoperative neurological deficits were assessed by manual muscle test and dynamometer. To validate the prognostic value of nTMS in recovery from upper-extremity paresis, the following were investigated: 1) the correlation between DHS-L and the serial grip strength change, and 2) the correlation between positive nTMS-MEP at 1 week after surgery and the serial grip strength change.

RESULTS From the presurgical nTMS study, MEPs from targeted muscles were identified in 13 cases from affected hemispheres. In one case, MEP was not evoked due to a huge tumor. Among 9 cases from which intraoperative DES mapping for hand motor area was available, hotspots for APB identified by nTMS were concordant with DES-positive sites. Compared with the adjacent group (DHS-L < 10 mm, n = 6), the nonadjacent group (DHS-L ≥ 10 mm, n = 7) showed significantly better recovery of grip strength at 3 months after surgery (p < 0.01). There were correlations between DHS-L and recovery of grip strength at 1 week, 3 weeks, and 3 months after surgery (r = 0.74, 0.68, and 0.65, respectively). Postsurgical nTMS was accomplished in 13 patients. In 9 of 13 cases, nTMS-MEP from APB muscle was positive at 1 week after surgery. Excluding the case in which nTMS-MEP was negative from the presurgical nTMS study, recoveries in grip strength were compared between 2 groups, in which nTMS-MEP at 1 week after surgery was positive (n = 9) or negative (n = 3). Significant differences were observed between the 2 groups at 1 week, 3 weeks, and 3 months after surgery (p < 0.01). Positive nTMS-MEP at 1 week after surgery correlated well with the motor recovery at 1 week, 3 weeks, and 3 months after surgery (r = 0.87, 0.88, and 0.77, respectively).

CONCLUSIONS Navigated TMS is a useful tool for identifying motor eloquent areas. The results of the present study have demonstrated the predictive value of nTMS in upper-extremity motor function recovery from postsurgical neurological deficits. The longer DHS-L and positive nTMS-MEP at 1 week after surgery have prognostic values of better recovery from postsurgical neurological deficits.

 

Predictors for Patient Discharge Destination After Elective Anterior Cervical Discectomy and Fusion

Spine 2017;42:1538–1544

Study Design. Retrospective study of prospectively collected data.

Objective. To identify risk factors for nonhome patient discharge after elective anterior cervical discectomy and fusion (ACDF).

Summary of Background Data. ACDF is one of the most performed spinal procedures and this is expected to increase in the coming years. To effectively deal with an increasing patient volume, identifying variables associated with patient discharge destination can expedite placement applications and subsequently reduce hospital length of stay.

Methods. The 2011 to 2014 ACS-NSQIP database was queried using Current Procedural Terminology (CPT) codes 22551 or 22554. Patients were divided into two cohorts based on discharge destination. Bivariate and multivariate logistic regression analyses were employed to identify predictors for patient discharge destination and extended hospital length of stay.

Results. A total of 14,602 patients met the inclusion criteria for the study of which 498 (3.4%) had nonhome discharge. Multivariate logistic regression found that Hispanic versus Black race/ ethnicity (odds ratio, OR¼0.21, 0.05–0.91, P¼0.037), American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander versus Black race/ethnicity (OR¼0.52, 0.34–0.80, p-value¼0.003), White versus Black race/ethnicity (OR¼0.55, 0.42–0.71), elderly age 65 years (OR¼3.32, 2.72–4.06), obesity (OR¼0.77, 0.63–0.93, P¼0.008), diabetes (OR¼1.32, 1.06–1.65, P¼0.013), independent versus partially/totally dependent functional status (OR¼0.11, 0.08–0.15), operation time 4hours (OR¼2.46, 1.87–3.25), cardiac comorbidity (OR ¼1.38, 1.10– 1.72, P ¼0.005), and ASA Class 3 (OR¼2.57, 2.05–3.20) were predictive factors in patient discharge to a facility other than home. In addition, multivariate logistic regression analysis also found nonhome discharge to be the most predictive variable in prolonged hospital length of stay.

Conclusion. Several predictive factors were identified in patient discharge to a facility other than home, many being preoperative variables. Identification of these factors can expedite patient discharge applications and potentially can reduce hospital stay, thereby reducing the risk of hospital acquired conditions and minimizing health care costs.

Level of Evidence: 3

Syndrome of the Trephined: A Systematic Review

syndrome-of-the-trephined-a-systematic-review

Neurosurgery 79:525–534, 2016

Syndrome of the trephined (SoT) is a rare, important complication of a craniectomy characterized by neurological dysfunction that improves with cranioplasty. Its varied symptoms include motor, cognitive, and language deficits. Its exact characterization appears suboptimal, with differing approaches of evaluation. Accordingly, this topic is in great need of further investigation.

OBJECTIVE: To accurately describe SoT and explore methods of an objective diagnosis/ evaluation.

METHODS: Electronic searches of PubMed, MEDLINE, Web of Knowledge, and PsycINFO databases used the key words “syndrome of the trephined” and “sinking skin flap.” Non–English-language and duplicate articles were eliminated. Title and abstract reviews were selected for relevance. Full-text reviews were selected for articles providing individual characteristics of SoT patients.

RESULTS: This review identified that SoT most often occurs in male patients (60%) at 5.1 6 10.8 months after craniectomy for neurotrauma (38%). The average reported craniectomy is 88.3 6 34.4 cm2 and usually exists with a “sunken skin flap” (93%). Symptoms most commonly include motor, cognitive, and language deficits (57%, 41%, 28%, respectively), with improvement after cranioplasty within 3.8 6 3.9 days. Functional independence with activities of daily living is achieved by 54.9% of patients after 2.9 6 3.4 months of rehabilitation. However, evaluation of SoT is inconsistent, with only 53% of reports documenting objective studies.

DISCUSSION: SoT is a variable phenomenon associated with a prolonged time to cranioplasty. Due to current weaknesses in objectivity, we hypothesize that SoT is often underdiagnosed and recommend a multifaceted approach for consistent evaluation.

CONCLUSION: SoT is a serious complication that lacks exact characterization and deserves future investigation. Improved understanding and recognition have important implications for early intervention and patient outcomes.

Early Rehabilitation Targeting Cognition, Behavior, and Motor Function After Lumbar Fusion A Randomized Controlled Trial

Spine 2010;35:848–857

Study Design. Open label randomized controlled trial with 3-, 6-, 12-month, and 2- to 3-year follow-up.

Objective. To investigate the effectiveness of a psychomotor therapy focusing on cognition, behavior, and motor relearning compared with exercise therapy applied during the first 3 months after lumbar fusion.

Summary of Background Data. Postoperative management after lumbar fusion commonly focuses on analgesic pain control and activities of daily living. After 3 months, exercise therapy is often implemented. No randomized controlled trial has investigated early rehabilitation techniques conducted during the first 3 months after surgery.

Methods. The study recruited 107 patients, aged 18 to 65 years, selected for lumbar fusion because of 12 months of symptomatic spinal stenosis, spondylosis, degenerative/isthmic spondylolisthesis, or degenerative disc disease. The exercise therapy group received a home program focusing on pain contingent training of back, abdominal, and leg muscle functional strength and endurance, stretching, and cardiovascular fitness. The psychomotor therapy group received a home program and 3 outpatient sessions focusing on modifying maladaptive pain cognitions, behaviors, and motor control. Rated questionnaires investigating functional disability, pain, health-related quality of life, functional self-efficacy, outcome expectancy, fear of movement/(re)injury, and coping were assessed at 3, 6, 12 months, and 2 to 3 years after surgery.

Results. Follow-up rates were 93% at 12 months and 81% at 2 to 3 years after surgery. Psychomotor therapy improved functional disability, self-efficacy, outcome expectancy, and fear of movement/(re)injury significantly more than exercise therapy at respective follow-up occasions. Similar results occurred for pain coping but group differences were nonsignificant at 2 to 3 years follow-up. Potentially clinical relevant higher reoperation rates occurred after psychomotor therapy but rates were within normal ranges.

Conclusion. The study shows that postoperative rehabilitation can be safely implemented during the first 3 months after lumbar fusion and should include measures to modify psychological as well as motor functions.