Preoperative spinal education for lumbar spinal stenosis: A feasibility study.

INTRODUCTION: Lumbar spinal stenosis (LSS) is a leading cause of chronic musculoskeletal pain among older adults. A common and costly intervention for the treatment of LSS is lumbar decompression with or without fusion (LSS surgery), which has mixed outcomes among patients. Prehabilitation is a strategy designed to optimize the consistency of positive surgical outcomes and promote patient self-efficacy, while attempting to mitigate postoperative complications. No efforts have investigated the prehabilitation strategies specifically for patients undergoing LSS surgery. OBJECTIVE: To determine the feasibility of delivery and acceptability by participants of a novel prehabilitation intervention for patients undergoing LSS surgery. DESIGN: Feasibility study. SETTING: Outpatient orthopedic clinic at an academic medical center. PARTICIPANTS: Patients at least 50 years of age, who were scheduled for LSS surgery between October 2020 and October 2021. INTERVENTION: PreOperative Spinal Education for Lumbar Spinal Stenosis (POSE-LSS), is a novel multimodal, education-focused, time-efficient prehabilitation program for patients undergoing LSS surgery. Participants received the following: (1) Educational booklet and video; (2) In-person physical therapy (PT) session; and (3) Telemedicine visit with a physiatrist. MAIN OUTCOME MEASURE(S): The primary outcomes of interest were feasibility and acceptability of intervention by participants. Key potential surgical outcomes were length of stay and discharge disposition. RESULTS: POSE-LSS was completed by all eligible participants enrolled (n = 15) indicating feasibility and acceptability. Potential effectiveness measures including length of stay and discharge disposition were positively associated with the POSE-LSS intervention. CONCLUSIONS: This study demonstrates that a novel prehabilitation intervention is feasible, acceptable, and appears positively associated with important short-term measures of postoperative recovery that may impact the trajectory of patient care following LSS surgery.

The use and timing of angioembolization in pediatric blunt liver and spleen injury.

BACKGROUND: Nonoperative management (NOM) is the standard of care for the management of blunt liver and spleen injuries (BLSI) in the stable pediatric patient. Angiography with embolization (AE) is used as an adjunctive therapy in the management of adult BLSI patients, but it is rarely used in the pediatric population. In this planned secondary analysis, we describe the current utilization patterns of AE in the management of pediatric BLSI. METHODS: After obtaining IRB approval at each center, cohort data was collected prospectively for children admitted with BLSI confirmed on CT at 10 Level I pediatric trauma centers (PTCs) throughout the United States from April 2013 to January 2016. All patients who underwent angiography with or without embolization for a BLSI were included in this analysis. Data collected included patient demographics, injury details, organ injured and grade of injury, CT finding specifics such as contrast blush, complications, failure of NOM, time to angiography and techniques for embolization. RESULTS: Data were collected for 1004 pediatric patients treated for BLSI over the study period, 30 (3.0%) of which underwent angiography with or without embolization for BLSI. Ten of the patients who underwent angiography for BLSI failed NOM. For patients with embolized splenic injuries, splenic salvage was 100%. Four of the nine patients undergoing embolization of the liver ultimately required an operative intervention, but only one patient required hepatorrhaphy and no patient required hepatectomy after AE. Few angiography studies were obtained early during hospitalization for BLSI, with only one patient undergoing angiography within 1 hour of arrival at the PTC, and 7 within 3 hours. CONCLUSION: Angioembolization is rarely used in the management of BLSI in pediatric trauma patients with blunt abdominal trauma and is generally used in a delayed fashion. However, when implemented, angioembolization is associated with 100% splenic salvage for splenic injuries. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Hepatic Metastasectomy in Pediatric Patients: An Observational Study.

BACKGROUND: The role of hepatectomy for metastatic disease in children is controversial. Rationales include potential cure, obtaining a diagnosis, and guiding chemotherapy decisions. This study examines the safety and utility of hepatic metastasectomy for children at a single institution. METHODS: After IRB approval (#22-1258), medical records were reviewed from 1995 to 2022 for children undergoing hepatic metastasectomy. En-bloc hepatectomies during primary tumor resection were excluded. RESULTS: Hepatic metastasectomy was performed in 16 patients for a variety of histologies. Median patient age was 12.2 years [IQR 6.9-22.6], and 13/16 patients were female (81 %). Number of hepatic metastases ranged from 1 to 23 and involved between 1 and 8 Couinaud segments. Anatomic resections included 4 hemihepatectomies and 1 sectionectomy. All other resections were nonanatomic. 3/6 resections for germ cell tumor (GCT) revealed only mature teratoma, driving adjuvant therapy decisions. When indicated, median time to adjuvant chemotherapy was 19 days [IQR 11-22]. No patients had Clavien-Dindo Class III or higher perioperative morbidity. Three patients (1 GCT, 1 adrenocortical carcinoma (ACC), and 1 gastric neuroendocrine tumor (GNET) experienced hepatic relapse. The patients with relapsed GCT and GNET are alive with disease at 17 and 135 months, respectively. The patient with ACC died of disease progression and liver failure. One patient with Wilms tumor experienced extrahepatic, retroperitoneal recurrence and died. With a median follow-up of 38 months, 10-year disease-specific and disease-free survival were 77 % and 61 %, respectively. CONCLUSIONS: Hepatic metastasectomy can be accomplished safely in children, may guide adjuvant therapy decisions, and is associated with long-term survival in selected patients. LEVEL OF EVIDENCE: Level IV. TYPE OF STUDY: Treatment Study, Case series with no comparison group.

Lower incidence of blunt cerebrovascular injury among young, properly restrained children: An ATOMAC multicenter study.

BACKGROUND: Motor vehicle collision (MVC) remains a leading cause of injury and death among children, but the proper use of child safety seats and restraints has lowered the risks associated with motor vehicle travel. Blunt cerebrovascular injury (BCVI) is rare but significant among children involved in MVC. This study reviewed the incidence of BCVI after MVC causing blunt injury to the head, face, or neck, comparing those that were properly restrained with those that were not. METHODS: A prospective, multi-institutional observational study of children younger than 15 years who sustained blunt trauma to the head, face, or neck (Abbreviated Injury Scale score >0) and presented at one of six level I pediatric trauma centers from 2017 to 2020 was conducted. Diagnosis of BCVI was made either by imaging or neurological symptoms at 2-week follow-up. Restraint status among those involved in MVC was compared for each age group. RESULTS: A total of 2,284 patients were enrolled at the 6 trauma centers. Of these, 521 (22.8%) were involved in an MVC. In this cohort, after excluding patients with missing data, 10 of 371 (2.7%) were diagnosed with a BCVI. For children younger than 12 years, none who were properly restrained suffered a BCVI (0 of 75 children), while 7 of 221 (3.2%) improperly restrained children suffered a BCVI. For children between 12 and 15 years of age, the incidence of BCVI was 2 of 36 (5.5%) for children in seat belts compared with 1 of 36 (2.8%) for unrestrained children. CONCLUSION: In this large multicenter prospectively screened pediatric cohort, the incidence of BCVI among properly restrained children under 12 years after MVC was infrequent, while the incidence was 3.2% among those without proper restraint. This effect was not seen among children older than 12 years. Restraint status in young children may be an important factor in BCVI screening. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Prehabilitation for spine surgery: A scoping review.

We aimed to identify and describe the current interventions used in preoperative programs ("prehabilitation") for spine surgery. Knowledge gaps in approaches, feasibility, timing, patient experience, clinical outcomes, and health care costs were explored while describing their potential benefits on physical and psychological outcomes. An electronic search was conducted from January 2004 to February 2022 in Ovid Medline, Embase, EBSCO CINAHL, the Cochrane Database of Systematic Reviews, and PEDro to identify studies in English evaluating adults enrolled in prehabilitation before undergoing elective spine surgeries. Studies were uploaded into DistillerSR for systematic screening after removing duplicates. Four reviewers screened nested references for inclusion based on titles and abstracts, followed by their full-text review. Two reviewers subsequently extracted data and summarized the results. The results were reported using Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines. Studies were rated for quality using National Health and Medical Research Council criteria. Out of 18,879 potential studies, a total of 23 studies (0.12%) met the eligibility criteria and were included in this scoping review. The prehabilitation programs included general education (n = 6, 26%), exercise (n = 6, 26%), cognitive behavioral therapy (n = 3, 13%), pain neuroscience education (n = 3, 13%), health behavior counseling (n = 3, 13%), and mindfulness (n = 2, 9%). Additional studies are needed to identify optimal patient characteristics, intervention dosage, and whether multimodal approaches using a combination of physical and psychological strategies lead to more favorable outcomes. Although studies on prehabilitation for spine surgery are limited, they seem to demonstrate that prehabilitation programs are feasible, reduce medical expenditures, and improve patients' postoperative pain, disability, self-efficacy, psychological behaviors, and satisfaction with surgical outcomes. The available literature suggests there is an opportunity to improve patient experience, clinical outcomes and reduce medical costs with the use of prehabilitation in spine surgery.

Diagnostic accuracy of screening tools for pediatric blunt cerebrovascular injury: An ATOMAC multicenter study.

BACKGROUND: Blunt cerebrovascular injury (BCVI) is rare but significant among children. There are three sets of BCVI screening criteria validated for adults (Denver, Memphis, and Eastern Association for the Surgery of Trauma criteria) and two that have been validated for use in pediatrics (Utah score and McGovern score), all of which were developed using retrospective, single-center data sets. The purpose of this study was to determine the diagnostic accuracy of each set of screening criteria in children using a prospective, multicenter pediatric data set. METHODS: A prospective, multi-institutional observational study of children younger than 15 years who sustained blunt trauma to the head, face, or neck and presented at one of six level I pediatric trauma centers from 2017 to 2020 was conducted. All patients were screened for BCVI using the Memphis criteria, but criteria for all five were collected for analysis. Patients underwent computed tomography angiography of the head or neck if the Memphis criteria were met at presentation or neurological abnormalities were detected at 2-week follow-up. RESULTS: A total of 2,284 patients at the 6 trauma centers met the inclusion criteria. After excluding cases with incomplete data, 1,461 cases had computed tomography angiography and/or 2-week clinical follow-up and were analyzed, including 24 cases (1.6%) with BCVI. Sensitivity, specificity, positive predictive value, and negative predictive value for each set of criteria were respectively 75.0, 87.5, 9.1, and 99.5 for Denver; 91.7, 71.1, 5.0, and 99.8 for Memphis; 79.2, 82.7, 7.1, and 99.6 for Eastern Association for the Surgery of Trauma; 45.8, 95.8, 15.5, and 99.1 for Utah; and 75.0, 89.5, 10.7, and 99.5 for McGovern. CONCLUSION: In this large multicenter pediatric cohort, the Memphis criteria demonstrated the highest sensitivity at 91.7% and would have missed the fewest BCVI, while the Utah score had the highest specificity at 95.8% but would have missed more than half of the injuries. Development of a tool, which narrows the Memphis criteria while maintaining its sensitivity, is needed for application in pediatric patients. LEVEL OF EVIDENCE: Diagnostic Test/Criteria; Level II.

Hemodilution in pediatric trauma: Defining the expected hemoglobin changes in patients with liver and/or spleen injury: An ATOMAC+ secondary analysis.

BACKGROUND: Many children with blunt liver and/or spleen injury (BLSI) never bleed intraperitoneally. Despite this, decreases in hemoglobin are common. This study examines initial and follow up measured hemoglobin values for children with BLSI with and without evidence of intra-abdominal bleeding. METHODS: Children ≤18 years of age with BLSI between April 2013 and January 2016 were identified from the prospective ATOMAC+ cohort. Initial and follow up hemoglobin levels were analyzed for 4 groups with BLSI: (1) Non bleeding; (2) Bleeding, non transfused (3) Bleeding, transfused, and (4) Bleeding resulting in non operative management (NOM) failure. RESULTS: Of 1007 patients enrolled, 767 were included in one or more of four study cohorts. Of 131 non bleeding patients, the mean decrease in hemoglobin was 0.83 g/dL (+/-1.35) after a median of 6.3 [5.1,7.0] hours, (p = 0.001). Follow-up hemoglobin levels in patients with and without successful NOM were not different. For patients with an initial hemoglobin >9.25 g/dL, the odds ratio (OR) for NOM failure was 14.2 times less, while the OR for transfusion was 11.4 times less (p = 0.001). CONCLUSION: Decreases in hemoglobin are expected after trauma, even if not bleeding. A hemoglobin decrease of 2.15 g/dL [0.8 + 1.35] would still be within one standard deviation of a non bleeding patient. An initial low hemoglobin correlates with failure of NOM as well as transfusion, thereby providing useful information. By contrast, subsequent hemoglobin levels do not appear to guide the need for transfusion, nor correlate with failure of NOM. These results support initial hemoglobin measurement but suggest a lack of utility for routine rechecking of hemoglobin. LEVEL OF EVIDENCE: Level II Prognostic Study.

Relationship between Physical Activity and Pain in U.S. Adults.

PURPOSE: We sought to assess the relationship between physical activity (PA) and pain within the available sample, with secondary aims to assess prevalence of pain, PA levels, health care seeking behaviors, and impact of pain on daily activities and work. METHODS: We conducted an epidemiological cross-sectional observational study utilizing National Health Interview Survey data from 2020. We examined the self-reported adherence to current PA guidelines and the prevalence of pain. We hypothesized those dealing with pain were less likely to meet PA guidelines. The PA levels, pain prevalence, frequency, and intensity were assessed via the survey and relationships explored via modeling. RESULTS: Of 31,568, 46% were men and 53.99% women with mean age of 52.27 yr (±17.31 yr). There were 12,429 (39.37%) participants that reported pain on some days, 2761 (8.75%) on most days, and 4661 (14.76%) every day. The odds of engaging in PA decreased in a stepwise fashion based on frequency and intensity of pain reporting when compared with no pain. Importantly, PA is a significant correlate affecting pain reporting, with individuals engaging in PA (strength and aerobic) demonstrating two times lower odds of reporting pain when compared with those not meeting the PA guidelines. CONCLUSIONS: There is a significant correlation between meeting PA guidelines and pain. Meeting both criteria of PA guidelines resulted in lower odds of reporting pain. In addition, the odds of participating in PA decreased based on pain frequency reporting. These are important findings for clinicians, highlighting the need for assessing PA not only for those dealing with pain but also as a potential risk factor for minimizing development of chronic pain.

Mitochondrial brain proteome acetylation levels and behavioural responsiveness to amphetamine are altered in mice lacking Sirt3.

Post-translational modification of mitochondrial proteins represents one mechanism by which the functional activity of mitochondria can be regulated. In the brain, these modifications can influence the functional properties of different neural circuitries. Given that the sirtuin family member Sirt3 represents the primary protein deacetylase enzyme in mitochondria, we tested whether brain mitochondrial proteome acetylation would increase in male or female mice lacking Sirt3. Our results confirm that whole brain mitochondrial proteome acetylation levels are indeed elevated in both sexes of Sirt3-KO mice relative to controls. Consistently, we found the mitochondria of mouse embryonic fibroblast (MEF) cells derived from Sirt3-KO mice were smaller in size, and fewer in number than in wild-type MEFs, and that mitochondrial free calcium levels were elevated within the mitochondria of these cells. As protein acetylation can influence mitochondrial function, and changes in mitochondrial function have been linked to alterations in neural circuit function regulating motor activity and anxiety-like behavior, we tested whether Sirt3-deficient mice would display sensitized responsiveness to the stimulant amphetamine. Both male and female Sirt3-KO mice displayed hyper-locomotion and attenuated anxiety-like behavior in response to a dose of amphetamine that was insufficient to promote any behavioural responses in wild-type mice. Collectively, these results confirm that Sirt3 regulates mitochondrial proteome acetylation levels in brain tissue, and that the absence of Sirt3 increases the sensitivity of neural systems to amphetamine-induced behavioural responses.

An exploration of low back pain beliefs in a Northern America based general population.

BACKGROUND: Prior research has demonstrated that people across different populations hold beliefs about low back pain (LBP) that are inconsistent with current evidence. Qualitative research is needed to explore current LBP beliefs in Northern America (NA). OBJECTIVES: We conducted a primarily qualitative cross-sectional online survey to assess LBP beliefs in a NA population (USA and Canada). METHODS: Participants were recruited online using social media advertisements targeting individuals in NA over the age of 18 with English speaking and reading comprehension. Participants answered questions regarding the cause of LBP, reasons for reoccurrence or persistence of LBP, and sources of these beliefs. Responses were analyzed using conventional (inductive) content analysis. RESULTS/FINDINGS: 62 participants were included with a mean age of 47.6 years. Most participants reported multiple causes for LBP as well as its persistence and reoccurrence, however, these were biomedically focused with minimal to no regard for psychological or environmental influences. The primary cited source of participants' beliefs was healthcare professionals. CONCLUSIONS: Our findings align with prior research from other regions, demonstrating a need for updating clinical education and public messaging about the biopsychosocial nature of LBP.

Direct Pars Repair with Cannulated Screws in Adults: A Case Series and Systematic Literature Review.

OBJECTIVE: Lumbar spondylolysis occurs in 5%-8% of adults. This study aimed to report clinical and radiographic outcomes of direct pars repair in adults with lumbar spondylolysis. METHODS: We conducted a retrospective review of all patients treated for lumbar spondylolysis via open fracture reduction and direct pars repair with cannulated screws using a lag technique. Demographics, clinical presentation, perioperative and intraoperative imaging, and postoperative data were collected. We subsequently performed a systematic review to describe radiographic and clinical outcomes following direct pars repair. RESULTS: Three patients were identified (mean age 40.3 years; range, 21-72 years; 2 male). All patients had bilateral L5 pars fractures treated via open, direct repair with cannulated screws. There were no intraoperative complications. Length of stay was <24 hours for each patient. All patients reported back/radicular symptom relief and returned to full-time manual labor by latest follow-up. Noncontrast lumbar computed tomography performed 14-20 months postoperatively confirmed that all patients had good bilateral screw placement without fracture. Two patients (21 and 28 years old at surgery) had evidence of fusion across fracture sites, while 1 patient exhibited radiolucency around the screws and no progression of spondylolisthesis. Additionally, we reviewed 8210 articles and included 15 in a systematic review of direct pars repair. Fusion rates were 67%-100%, with improved average Oswestry Disability Index and visual analog scale back pain scores by latest follow-up. CONCLUSIONS: Lumbar spondylolysis treatment with open fracture reduction and direct pars repair with cannulated screws in adults is safe and may result in mechanical back/radicular pain relief, even in the absence of radiographic fusion.

Third-degree full-thickness burns as a complication of cervical radiofrequency ablation.

A 46-year-old woman underwent a cervical radiofrequency ablation (RFA) for chronic neck pain. Following the procedure, two areas surrounding the grounding pad in the lumbar region developed full thickness third-degree burns. Burn injuries following cervical RFA are rarely reported and are most often associated with cardiac and solid tumour RFA. Only one other case has been reported in literature with a similar outcome following a thoracic facet RFA. In our case, the lesion was directly from the ground pad and not from the radiofrequency electrode, which is more often the culprit. This is the first case reported in the literature of a full-thickness skin burn from a cervical RFA. Physicians should be aware of the potential for severe burns around the RF probe and ground pad as sequelae of RFA, and we caution the use of sedation during the procedure, as patients will unlikely be able to report any unusual sensation.

Electrographic Features of Spontaneous Recurrent Seizures in a Mouse Model of Extended Hippocampal Kindling.

Epilepsy is a chronic neurological disorder characterized by spontaneous recurrent seizures (SRS) and comorbidities. Kindling through repetitive brief stimulation of a limbic structure is a commonly used model of temporal lobe epilepsy. Particularly, extended kindling over a period up to a few months can induce SRS, which may simulate slowly evolving epileptogenesis of temporal lobe epilepsy. Currently, electroencephalographic (EEG) features of SRS in rodent models of extended kindling remain to be detailed. We explored this using a mouse model of extended hippocampal kindling. Intracranial EEG recordings were made from the kindled hippocampus and unstimulated hippocampal, neocortical, piriform, entorhinal, or thalamic area in individual mice. Spontaneous EEG discharges with concurrent low-voltage fast onsets were observed from the two corresponding areas in nearly all SRS detected, irrespective of associated motor seizures. Examined in brain slices, epileptiform discharges were induced by alkaline artificial cerebrospinal fluid in the hippocampal CA3, piriform and entorhinal cortical areas of extended kindled mice but not control mice. Together, these in vivo and in vitro observations suggest that the epileptic activity involving a macroscopic network may generate concurrent discharges in forebrain areas and initiate SRS in hippocampally kindled mice.

Developments in Minimally Invasive Surgical Options for Vertebral Pain: Basivertebral Nerve Ablation - A Narrative Review.

Historically, intervertebral disc degeneration has been the etiological target of chronic low back pain; however, disc degeneration is not necessarily directly associated with pain, and many other anatomical structures are potential etiologies. The vertebral endplates have been postulated to be a source of vertebral pain, where these endplates become particularly susceptible to increased expression of nociceptors and inflammatory proliferation carried by the basivertebral nerve (BVN), expressed on diagnostic imaging as Modic changes. This is useful diagnostic information that can help physicians to phenotype a subset of low back pain, which is known as vertebral pain, in order to directly target interventions, such as BVN ablation, to this significant pain generator. Therefore, this review describes the safety, efficacy, and the rationale behind the use of BVN ablation, a minimally invasive spinal intervention, for the treatment of vertebral pain. Our current literature review of available up-to-date publications utilizing BVN ablation in the treatment of vertebral pain suggests that there is limited, but moderate-quality evidence that this is an effective intervention for reduction of disability and improvement in function, at short- and long-term follow-up, in addition to limited moderate-quality evidence that BVN RFA is superior to conservative care for pain reduction, at least at 3-month follow-up. Our review concluded that there is a highly clinical and statistically significant treatment effect of BVN ablation for vertebral pain with clinically meaningful benefits in pain reduction, functional improvements, opioid dose reduction, and improved quality of life. There were no reported device-related patient deaths or serious AEs based on the available literature. BVN ablation is a safe, well-tolerated and clinically beneficial intervention for vertebral pain, when proper patient selection and surgical/procedural techniques are applied.

A Required, Combined Neurology-Physical Medicine and Rehabilitation Clerkship Addresses Clinical and Health Systems Knowledge Gaps for Fourth-Year Medical Students.

ABSTRACT: This study evaluated the impact of a 4-wk mandatory neurology-physical medicine and rehabilitation advanced-core clerkship for fourth-year medical students. The combined clerkship encouraged an interdisciplinary and function-based approach to the management of common neurologic, musculoskeletal, and pain complaints. Seventy-three fourth-year medical students participated in the rotation over 1 yr. A survey assessing knowledge and skill set topics was conducted before and after the clerkship. Qualitative feedback regarding the rotation was provided by the students and analyzed. Significant gaps in knowledge and skill sets were identified before the clerkship and successfully addressed by combined teaching modalities. These data demonstrate that an integrated neurology-physical medicine and rehabilitation clerkship can improve students' confidence in multiple domains. Integrating physical medicine and rehabilitation into core clerkships at other medical schools may provide an avenue to address curriculum gaps.

Early vasopressor administration in pediatric blunt liver and spleen injury: An ATOMAC+ study.

BACKGROUND: No prior studies have examined the outcomes of early vasopressor use in children sustaining blunt liver or spleen injury (BLSI). METHODS: A planned secondary analysis of vasopressor use from a 10-center, prospective study of 1004 children with BLSI. Inverse probability of treatment weighting (IPTW) was used to compare patients given vasopressors <48 h after injury to controls based on pretreatment factors. A logistic regression was utilized to assess survival associated with vasopressor initiation factors on mortality and nonoperative management (NOM) failure. RESULTS: Of 1004 patients with BLSI, 128 patients were hypotensive in the Pediatric Trauma Center Emergency Department (ED); 65 total patients received vasopressors. Hypotension treated with vasopressors was associated with a sevenfold increase in mortality (AOR = 7.6 [p < 0.01]). When excluding patients first given vasopressors for cardiac arrest, the risk of mortality increased to 11-fold (AOR = 11.4 [p = 0.01]). All deaths in patients receiving vasopressors occurred when started within the first 12 h after injury. Vasopressor administration at any time was not associated with NOM failure. CONCLUSION: After propensity matching, early vasopressor use for hypotension in the ED was associated with an increased risk of death, but did not increase the risk of failure of NOM. LEVEL OF EVIDENCE: Level III prognostic and epidemiological, prospective.

Interregulation between fragile X mental retardation protein and methyl CpG binding protein 2 in the mouse posterior cerebral cortex.

Several X-linked neurodevelopmental disorders including Rett syndrome, induced by mutations in the MECP2 gene, and fragile X syndrome (FXS), caused by mutations in the FMR1 gene, share autism-related features. The mRNA coding for methyl CpG binding protein 2 (MeCP2) has previously been identified as a substrate for the mRNA-binding protein, fragile X mental retardation protein (FMRP), which is silenced in FXS. Here, we report a homeostatic relationship between these two key regulators of gene expression in mouse models of FXS (Fmr1 Knockout (KO)) and Rett syndrome (MeCP2 KO). We found that the level of MeCP2 protein in the cerebral cortex was elevated in Fmr1 KO mice, whereas MeCP2 KO mice displayed reduced levels of FMRP, implicating interplay between the activities of MeCP2 and FMRP. Indeed, knockdown of MeCP2 with short hairpin RNAs led to a reduction of FMRP in mouse Neuro2A and in human HEK-293 cells, suggesting a reciprocal coupling in the expression level of these two regulatory proteins. Intra-cerebroventricular injection of an adeno-associated viral vector coding for FMRP led to a concomitant reduction in MeCP2 expression in vivo and partially corrected locomotor hyperactivity. Additionally, the level of MeCP2 in the posterior cortex correlated with the severity of the hyperactive phenotype in Fmr1 KO mice. These results demonstrate that MeCP2 and FMRP operate within a previously undefined homeostatic relationship. Our findings also suggest that MeCP2 overexpression in Fmr1 KO mouse posterior cerebral cortex may contribute to the fragile X locomotor hyperactivity phenotype.