Effect of transcutaneous auricular vagus nerve stimulation on major depressive disorder: A nonrandomized controlled pilot study

BACKGROUND

Depression presents a significant burden to both patients and society. One treatment that has emerged is vagus nerve stimulation (VNS), an FDA-approved physical treatment for depressive disorders. However, the application of this intervention has been limited by the involvement of surgery and potential side effects. The aim of this study is to explore the effectiveness of stimulating the superficial branches of the vagus nerve as a solo treatment for MDD.

METHODS

This is a nonrandomized, controlled study. The first cohort of patients (n=91) only received transcutaneous auricular VNS (taVNS) for 12 weeks. In the second cohort (n=69), patients first received 4 weeks of sham taVNS followed by 8 weeks of taVNS. All treatments were self-administered by the patients at home after they received training from the hospitals. The primary outcome measurement was the 24-item Hamilton Depression Rating Scale measured at weeks 0, 4, 8, and 12. Data analysis included a timelag analysis comparing (1) real and sham taVNS groups at week 4; (2) the real taVNS group at week 4 vs the sham taVNS group at week 8 (fourth week of real taVNS following 4 weeks of sham); and (3) the real taVNS group at week 8 vs the sham taVNS group at week 12 (eighth week of real taVNS following sham).

RESULTS

After four weeks of treatment, MDD patients in the taVNS group showed greater improvement than patients in the sham taVNS group as indicated by Hamilton score changes as well as response and remission rates at week four. In addition, we also found that the clinical improvements continued until week 12 during taVNS.

LIMITATIONS

Patients were not randomized in this study.

CONCLUSIONS

Our results suggest that taVNS is a promising, safe, and cost-effective therapeutic method for mild and moderate MDD.

The auriculo-vagal afferent pathway and its role in seizure suppression in rats

BACKGROUND

The afferent projections from the auricular branch of the vagus nerve (ABVN) to the nucleus tractus solitaries (NTS) have been proposed as the anatomical basis for the increased parasympathetic tone seen in auriculo-vagal reflexes. As the afferent center of the vagus nerve, the NTS has been considered to play roles in the anticonvulsant effect of cervical vagus nerve stimulation (VNS). Here we proposed an "auriculo-vagal afferent pathway" (AVAP), by which transcutaneous auricular vagus nerve stimulation (ta-VNS) suppresses pentylenetetrazol (PTZ)-induced epileptic seizures by activating the NTS neurons in rats.

RESULTS

The afferent projections from the ABVN to the NTS were firstly observed in rats. ta-VNS increased the first grand mal latency of the epileptic seizure and decreased the seizure scores in awake rats. Furthermore, when the firing rates of the NTS neurons decreased, epileptiform activity manifested as electroencephalogram (EEG) synchronization increased with 0.37±0.12 s delay in anaesthetized rats. The change of instantaneous frequency, mean frequency of the NTS neurons was negative correlated with the amplitude of the epileptic activity in EEG traces. ta-VNS significantly suppressed epileptiform activity in EEG traces via increasing the firing rates of the neurons of the NTS. In comparison with tan-VNS, the anticonvulsant durations of VNS and ta-VNS were significantly longer (P<0.01). There was no significant difference between the anticonvulsant durations of VNS and ta-VNS (P>0.05). The anticonvulsant effect of ta-VNS was weakened by reversible cold block of the NTS.

CONCLUSIONS

There existed an anatomical relationship between the ABVN and the NTS, which strongly supports the concept that ta-VNS has the potential for suppressing epileptiform activity via the AVAP in rats. ta-VNS will provide alternative treatments for neurological disorders, which can avoid the disadvantage of VNS.

Neural mechanism of acupuncture-modulated gastric motility

AIM: To investigate the acupuncture-modulated gastric motility and its underlying neural mechanism.

METHODS: Intragastric pressure and/or waves of gastric contraction in rats were recorded by intrapyloric balloon and changes of gastric motility induced by acupuncture stimulation were compared with the background activity before any stimulation. Gastro-vagal or splanchnic-sympathetic nerves were recorded or cut respectively for investigating the involvement of autonomic nerve pathways. Spinalization experiment was also performed.

RESULTS: Acupuncture-stimulation by exciting Aδ and/or C afferent fibers, could only modulate gastric motility. Acupuncture-stimulation on fore- and hind-limbs evoked a moderate gastric motility followed by increased vagus discharges with unchanged sympathetic activity, while the same stimulus to the acupoints in abdomen resulted in reversed effects on gastric motility and autonomic nervous activities. The inhibitory gastric response was completely abolished by splanchnic denervation, but the facilitative gastric response to stimulation of acupoints in limbs was not influenced, which was opposite to the effect when vagotomy was performed. The similar depressive effects were produced by the stimulation at the acupoints homo-segmental to the gastric innervation in the animals with or without spinalization. However, the facilitation induced by the stimulation at the acupoints hetero-segmental to the gastric innervation was not observed in the spinalized animals.

CONCLUSION: Facilitative effects of stimulating hetero-segmental acupoints are involved in the intact preparation of vagal nerves and spinal cord, while the inhibitory response induced by stimulating homo-segmental acupoints is involved in the intact preparation of sympathetic nerves. Only the acupuncture-stimulation with intensity over the threshold of Aδ and/or C afferent fibers can markedly modulate gastrointestinal motility.

Transcutaneous vagus nerve stimulation for the treatment of depression: a study protocol for a double blinded randomized clinical trial

Background

Depressive disorders are the most common form of mental disorders in community and health care settings. Unfortunately, the treatment of Major Depressive Disorder (MDD) is far from satisfactory. Vagus nerve stimulation (VNS) is a relatively new and promising physical treatment for depressive disorders. One particularly appealing element of VNS is the long-term benefit in mood regulation. However, because this intervention involves surgery, perioperative risks, and potentially significant side effects, this treatment has been limited to those patients with treatment-resistant depression who have failed medication trials and exhausted established somatic treatments for major depression, due to intolerance or lack of response.

This double-blinded randomized clinical trial aims to overcome these limitations by introducing a novel method of stimulating superficial branches of the vagus nerve on the ear to treat MDD. The rationale is that direct stimulation of the afferent nerve fibers on the ear area with afferent vagus nerve distribution should produce a similar effect as classic VNS in reducing depressive symptoms without the burden of surgical intervention.

Design

One hundred twenty cases (60 males) of volunteer patients with mild and moderate depression will be randomly divided into transcutaneous vagus nerve stimulation group (tVNS) and sham tVNS group. The treatment period lasts 4 months and all clinical and physiological measurements are acquired at the beginning and the end of the treatment period.

Discussion

This study has the potential to significantly extend the application of VNS treatment for MDD and other disorders (including epilepsy, bipolar disorder, and morbid obesity), resulting in direct benefit to the patients suffering from these highly prevalent disorders. In addition, the results of this double-blinded clinical trial will shed new light on our understanding of acupuncture point specificity, and development of methodologies in clinical trials of acupuncture treatment.

Trials registration

Clinical Trials. ChiCTR-TRC-11001201 http://www.chictr.org/cn/

A C-fiber reflex inhibition induced by electroacupuncture with different intensities applied at homotopic and heterotopic acupoints in rats selectively destructive effects on myelinated and unmyelinated afferent fibers

The aims of this study were to explore the C-fiber reflex inhibition induced by electroacupuncture with different intensities applied at homotopic or heterotopic acupoints, and to determine the influence selectively destroyed myelinated and unmyelinated afferent fibers on the C-fiber reflex inhibition. In the ipsilateral local acupoint, the general behavior of the C-fiber reflex can be depressed by electroacupuncture below the threshold of Adelta-fiber activation. Electroacupuncture stimulation within the intensity of Adelta-fiber activation applied to the ipsilateral limb pretreated with cobra venom did not elicit inhibition of C-fiber reflex in rats with demyelinated sciatic nerve. However, heterotopic electroacupuncture below the threshold of Adelta-fiber activation was totally ineffective. In contralateral heterotopic acupoints, the C-fiber reflex can be depressed only by electroacupuncture with stimulating intensities exceeding thresholds of Adelta and C-fiber activation. Electroacupuncture stimuli applied to capsaicin-pretreated limb in the intensities of threshold of Adelta-fiber and treble thresholds of C-fiber activation produced only a little inhibition of C-fiber reflex. Inhibitory intensity was roughly similar to that induced by the stimulation with intensity for the activation of Adelta-fiber in normal animal. In the spinalized animals transections at T6-T7 segments, regardless of intensities, the homotopic electroacupuncture stimulation only induced moderate depression of C-fiber reflex similar to that of Adelta-fiber activation; whereas, no matter what intensities of application, the inhibitory effects of C-fiber reflex disappeared totally by using heterotopic noxious electroacupuncture in these animals.

Acupuncture-like stimulation at auricular point Heart evokes cardiovascular inhibition via activating the cardiac-related neurons in the nucleus tractus solitarius

Fifty-eight male Sprague-Dawley rats used in the present study to investigate the role of baroreceptor sensitive neurons of the nucleus tractus solitarius (NTS) in the regulation of cardiovascular inhibition during acupuncture at the auricular point Heart, single unit recording was made in anesthetized Sprague-Dawley rats. A neuron was considered to be excited or inhibited by acupuncture stimulation if it displayed 15% more or less spikes s(-1), respectively. NTS neurons were classified into cardiac-related (CR) neurons and non-cardiac-related neurons based on whether their rhythmic discharges were synchronized with the R-waves and responding to sodium nitroprusside (NP; 20 μg/kg, i.v.) administration. Manual acupuncture was applied at the auricular point Heart and somatic acupuncture points ST36 and PC6. Acupuncture at auricular point Heart showed a more significant inhibitory effect on arterial pressure (-22.1±2.4mm Hg; P<0.001) and heart rate (-12.7±1.7 bpm; P<0.001) than that at ST36 and PC6. Acupuncture at auricular point Heart also increased the level of response of CR neurons in the NTS (93.8%±26.0% increase in discharge rate; P<0.01). Systemic or local administration of atropine attenuated the cardiovascular inhibition and activation of CR neurons evoked by auricular acupuncture, but had no effect on the same responses evoked by somatic acupuncture. Inactivation of the NTS with local anesthetics also decreased the cardiovascular inhibitory responses evoked by auricular acupuncture. Our results show that acupuncture at the auricular point Heart regulates cardiovascular function by activating baroreceptor sensitive neurons in the NTS in a similar manner as the baroreceptor reflex in cardiovascular inhibition.

Transcutaneous vagus nerve stimulation for refractory epilepsy: a randomized controlled trial

This trial was designed to test the safety and effectiveness of transcutaneous auricular vagus nerve stimulation (ta-VNS) for patients with refractory epilepsy.Pre-trial：144 patients were randomly assigned to ta-VNS group (n=98) or transcutaneous auricular non-vagus nerve stimulation (tn-VNS) control group (n=46). Treatment was conducted twice per day for 24 weeks. After 8, 16 and 24 weeks of treatment，the patients were evaluated according to the Modified Engel Scale (four classes). After 8 weeks，according to the medical ethic design, patients in tn-VNS group were switched into ta-VNS group uniquely. After 8 weeks' treatment 41.0% and 27.5% of patients from ta-VNS and tn-VNS groups, respectively, experienced reduction in seizure frequency that reached I, II and III levels according to the standards of the Modified Engel Scale compared with the baselines, indicating significant difference in seizure reduction between the two groups. After 24 weeks of treatment, ta-VNS patients had a 47.7% reduction, and tn-VNS, with an additional 16 weeks of treatment, reached 47.5% in reduction. After 8 weeks' treatment, the percentages of average seizure frequency in ta-VNS and tn-VNS were reduced by 42.6% and 11.5% respectively, providing a statistically significant difference in the results between the two groups (P<0.05). In addition, there were significant improvements in electroencephalograph (EEG) and the quality of daily life of the patients after treatment.The results show that this ta-VNS treatment can effectively reduce the frequency of seizures and improve the patient's quality of life. This may be an effective treatment for refractory epilepsy. At the same time，it is also safe，economic, and widely applicable.

Effective regularity in modulation on gastric motility induced by different acupoint stimulation

AIM: To investigate whether manual acupuncture at representative acupoints in different parts of the body can modulate responses of gastric motility in rats and regular effects in different acupoint stimulation.

METHODS: The gastric motor activity of rats was recorded by the intrapyloric balloon. The changes of gastric motility induced by the stimulation were compared with the background activity in intragastric pressure and/or waves of gastric contraction recorded before any stimulation. Morphological study was also conducted by observing the Evans dye extravasation in the skin after mustard oil injection into the intragastric mucous membrane to certify cutaneous innervations of blue dots related to gastric segmental innervations.

RESULTS: In all six rats that received mustard oil injections into intragastric mucosa, small blue dots appeared in the skin over the whole abdomen, but mainly in peri-midline upper- and middle- abdomen and middle-back, a few in thigh and groin. It may speculate that cutaneous innervations of blue dots have the same distribution as gastric segmental innervations. Acu-stimulation in acupoints of head-neck, four limbs, upper chest-dorsum and lower-dorsum induced markedly augmentation of gastric motility (acupoints on head-neck such as St-2: n = 16, 105.19 ± 1.36 vs 112.25 ± 2.02 and St-3: n = 14, 101.5 ± 1.75 vs 109.36 ± 1.8; acupoints on limbs such as Sp-6: n = 19, 100.74 ± 1.54 vs 110.26 ± 3.88; St-32: n = 17, 103.59 ± 1.64 vs 108.24 ± 2.41; St-36: n = 16, 104.81 ± 1.72 vs 110.81 ± 2.74 and Li-11: n = 17, 106.47 ± 2.61 vs 114.77 ± 3.77, P < 0.05-0.001). Vigorous inhibitory regulations of gastric motility induced by acu-stimulation applied in acupoints on whole abdomen and middle-dorsum were significantly different as compared with the controls before acu-stimulation (abdomen acupoints such as Cv-12: n = 11, 109.36 ± 2.09 vs 101 ± 2.21; Cv-6: n = 18, 104.39 ± 1.42 vs 91.83 ± 3.22 and St-21: n = 12, 107 ± 2.97 vs 98.58 ± 2.81; acupoints on middle-dorsum such as Bl-17: n = 19, 100.63 ± 1.4 vs 92.21 ± 2.07 and Bl-21: n = 19, 103.84 ± 1.48 vs 97.58 ± 2.16, P < 0.05-0.001).

CONCLUSION: Regular regulatory effects of facilitation and inhibition on gastric motility appear to be somatotopically organized in the acupoints of whole body, and the effective regularity of site-special acupoints on gastric motility is involved in segmental innervations between stomach and acupoints.

Acupuncture inhibition on neuronal activity of spinal dorsal horn induced by noxious colorectal distention in rat

AIM: To observe how acupuncture stimulation influences the visceral nociception in rat and to clarify the interactions between acupuncture or somatic input and visceral nociceptive inputs in the spinal dorsal horn. These will provide scientific base for illustrating the mechanism of acupuncture on visceral pain.

METHODS: Experiments were performed on Sprague-Dawley rats and the visceral nociceptive stimulus was generated by colorectal distention (CRD). Unit discharges from individual single neuron were recorded extracellularly with glass-microelectrode in L_1-3 spinal dorsal horn. Acupuncture stimulation was applied at contralateral heterotopic acupoint and ipsilateral homotopic acupoint, both of which were innervated by the same segments that innervate also the colorectal-gut.

RESULTS: The visceral nociception could be inhibited at the spinal level by the heterotopic somatic mechanical stimulation and acupuncture. The maximal inhibition was induced by acupuncture or the somatic noxious stimulation at spinal dorsal horn level with inhibiting rate of 68.61% and 60.79%, respectively (P<0.01 and <0.001). In reversible spinalized rats (cervical-thoracic cold block) both spontaneous activity and responses to CRD increased significantly in 16/20 units examined, indicating the existence of tonic descending inhibition. The inhibition of acupuncture on the noxious CRD disappeared totally in the reversible spinalized rats (P<0.001).

CONCLUSION: The inputs of noxious CRD and acupuncture may interact at the spinal level. The nociceptive visceral inputs could be inhibited by acupuncture applied to hetero-topic acupoint. The effect indicates that the spinal dorsal horn plays a significant role in mediating the inhibition of acupuncture and somatic stimulation on the neuronal response to the noxious visceral stimulation and the inhibition is modulated by upper cervical cord and/or supra-spinal center.

Observation of Pain-Sensitive Points along the Meridians in Patients with Gastric Ulcer or Gastritis

This study aims to investigate the sensitization of human skin points along certain meridians related to visceral disease by using the pressure-pain threshold (PPT) as an indicator. We detected and compared the PPTs of people with and without gastric ulcer or gastritis on the related acupoints, abdomen area, and back area with von Frey detector and observed the similarities and differences under their respective physiological and pathological states. The results showed that (1) the PPTs of patients with gastric ulcer on related acupoints decreased significantly compared with the control group; (2) there was no significant difference in PPT between the chosen points of the measured meridian and the adjacent nonacupoints; (3) there was an apparent distribution of tender points on the relevant abdomen and back regions of patients with gastric ulcer or gastritis, but none was found on the control group; (4) the pain-sensitive points of gastric ulcer and gastritis patients were BURONG (ST19), LIANGMEN (ST21), and HUAROUMEN (ST24) of the stomach meridian on the abdominal region and PISHU (BL20), WEISHU (BL21), and WEICANG (BL50) on the back, among others The results suggest that the practical significance of acupoints may lie in its role as a relatively sensitive functional area. In a pathological state, the reflex points on the skin which are related to certain visceral organs become sensitive and functionally intensify.

Auricular Acupuncture May Suppress Epileptic Seizures via Activating the Parasympathetic Nervous System: A Hypothesis Based on Innovative Methods

Auricular acupuncture is a diagnostic and treatment system based on normalizing the body's dysfunction. An increasing number of studies have demonstrated that auricular acupuncture has a significant effect on inducing parasympathetic tone. Epilepsy is a neurological disorder consisting of recurrent seizures resulting from excessive, uncontrolled electrical activity in the brain. Autonomic imbalance demonstrating an increased sympathetic activity and a reduced parasympathetic activation is involved in the development and progress of epileptic seizures. Activation of the parasympathetic nervous system such as vagus nerve stimulation has been used for the treatment of intractable epilepsy. Here, we propose that auricular acupuncture may suppress epileptic seizures via activating the parasympathetic nervous system.

Neurons in the nucleus tractus solitarius mediate the acupuncture analgesia in visceral pain rats

The study investigated the role of nucleus tractus solitarius (NTS) neurons in electroacupuncture (EA) analgesia in colorectal distension (CRD) rats. NTS neurons responding to both CRD test and EA conditioning stimulations were considered somato-visceral convergent neurons. The neuronal activities evoked by graded CRD showed multiple firing patterns indicating multisynaptic connections. Some of the CRD excitatory neurons were inhibited by EA and vice versa. There was no discrepancy among different acupoints in inducing the changes of unit discharges. Conclusively, EA could regulate CRD related neurons in the NTS through polysynaptic cross-talk mechanism, which mediates EA analgesia on visceral pain in anesthetized rats.

Transcutaneous auricular vagus nerve stimulation triggers melatonin secretion and is antidepressive in Zucker diabetic fatty rats

Decreased circulating melatonin is implicated in depression. We recently found that Zucker diabetic fatty rats (ZDF, fa/fa) develop depression-like behaviors and that transcutaneous auricular vagus nerve stimulation (taVNS) is antidepressive in ZDF rats. Here we studied whether the ZDF rats could be used as a depression rodent model and whether the antidepressive effect of taVNS is mediated through modulation of melatonin secretion. Adult male ZDF and Zucker lean (ZL, fa/+) littermates were used. 30 min-taVNS procedures (2/15 Hz, 2 mA) were administered once daily under anesthesia for 34 consecutive days in pineal intact ZDF (n = 8) and ZL (n = 6) rats, as well as in pinealectomized ZDF rats (n = 8). Forced swimming test (FST) was used to determine depression-like behavior and ELISA to detect plasma melatonin concentration on day 35. We found that naïve ZDF rats had a longer immobility time in FST and that long-term (34 days) taVNS treatment ameliorated the depression-like behavior. In both pineal intact and pinealectomized ZDF rats, taVNS induced acute melatonin secretion, both during and after the taVNS session. A low melatonin level is related to the poor FST performance in ZDF rats (R = -0.544) in contrast to ZL rats (R = 0.247). In conclusion, our results show that ZDF rats are ideal candidates of innate depression and that taVNS is antidepressive through triggering melatonin secretion and increasing its production.

Patient Acceptable Symptom State, Minimal Clinically Important Difference, and Substantial Clinical Benefit After Arthroscopic Superior Capsular Reconstruction

BACKGROUND

Patient Acceptable Symptom State (PASS), minimal clinically important difference (MCID), and substantial clinical benefit (SCB) have rarely been assessed after arthroscopic superior capsular reconstruction (ASCR) with fascia lata autograft.

PURPOSE

(1) To investigate PASS, MCID, and SCB values for pain visual analog scale (pVAS), American Shoulder and Elbow Surgeons (ASES) score, Constant score, and Single Assessment Numeric Evaluation (SANE) after ASCR with fascia lata autograft, (2) to investigate factors for achieving PASS, MCID, and SCB.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

We retrospectively collected data from patients who underwent ASCR between June 2013 and October 2020. A total of 88 patients were included, and anchor questions for deriving PASS, MCID, and SCB values were applied at a minimum 1-year follow-up postoperatively. PASS, MCID, and SCB were derived using sensitivity- and specificity-based approaches. Univariable and multivariable logistic regression analyses were performed to determine factors for achieving PASS, MCID, and SCB.

RESULTS

Based on receiver operating characteristic curves, all 4 scores had acceptable area under the curve values (>0.7) for PASS, MCID, and SCB values. The PASS, MCID, and SCB values were 1.5, 2.5, and 4.5 for pVAS; 81.0, 19.0, and 27.5 for the ASES score; 60.5, -0.5, and 5.5 for the Constant score; and 75.0, 27.5, and 32.5 for SANE, respectively. Poor preoperative scores were related to significantly higher odds ratios (ORs) for achieving MCID and SCB. Wide acromiohumeral distance and dominant side were related to higher ORs for achieving PASS for the ASES score, and subscapularis tear was related to lower ORs for achieving PASS for pVAS and SCB for the Constant score.

CONCLUSION

Reliable PASS, MCID, and SCB values were achieved for at least 1 year after ASCR surgery. Poor preoperative score, wide acromiohumeral distance, and dominant side all demonstrated higher ORs for at least one value, but a subscapularis tear demonstrated lower ORs for achieving PASS for pVAS and SCB for the Constant score.

Effect of Fatty Infiltration of the Infraspinatus Muscle on Outcomes and Graft Failure After Arthroscopic Superior Capsule Reconstruction for Irreparable Posterosuperior Rotator Cuff Tears

BACKGROUND

Superior capsule reconstruction (SCR) was developed as an alternative treatment for irreparable rotator cuff tears to restore superior stability of the glenohumeral joint. Although fatty infiltration (FI) of the rotator cuff muscles, especially the infraspinatus, has been implicated as a predictor of outcomes and graft integrity after rotator cuff repair, it has not been fully investigated in cases of SCR.

PURPOSE

To evaluate the effect of FI of the infraspinatus muscle on clinical and radiological outcomes after SCR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 55 consecutive patients with irreparable posterosuperior rotator cuff tears who underwent SCR between January 2013 and August 2020 were included retrospectively. Preoperative and postoperative clinical and radiological findings (median follow-up of >2 years), including magnetic resonance imaging results, were thoroughly reviewed. The patients were divided into 2 groups: group 1 with mild FI of the infraspinatus (Goutallier grades 0-2) and group 2 with severe FI of the infraspinatus (Goutallier grades 3-4). The American Shoulder and Elbow Surgeons score, Constant score, visual analog scale score for pain, and range of motion were evaluated. Acromiohumeral distance and rotator cuff tear arthropathy using the Hamada classification were assessed on plain radiography. Postoperative graft integrity was evaluated by magnetic resonance imaging. Graft failure was defined as complete discontinuity. Univariate and multivariable logistic regression analyses were performed to evaluate clinical and radiological findings that might be associated with successful SCR.

RESULTS

Clinical and radiological outcomes significantly improved after SCR. Graft failure was noted in 15 (27.3%) patients and was more frequent in group 2 than in group 1 (50.0% vs 14.3%, respectively; P = .004). Univariate analysis indicated a significant association between severe FI in the infraspinatus (group 2) and graft failure after SCR (odds ratio, 6.00 [95% CI, 1.65-21.80]; P = .006). Multivariable analysis indicated that FI of the infraspinatus was the only factor associated with graft failure (odds ratio, 6.37 [95% CI, 1.63-24.90]; P = .008).

CONCLUSION

Severe FI of the infraspinatus muscle was a factor indicating a poor prognosis for graft integrity after SCR. Preoperative evaluation of FI in the rotator cuff muscles can help predict postoperative outcomes and may help guide therapeutic options.

Early Postoperative MRI Evaluation of a Fascia Lata Autograft With and Without Polypropylene Mesh Augmentation After Superior Capsular Reconstruction

BACKGROUND

Recently, a polypropylene mesh has been introduced and reported to improve clinical outcomes after superior capsular reconstruction (SCR) using a fascia lata autograft (FLA). However, mesh-related events such as a foreign body response may trigger inflammation, which might affect graft healing and remodeling.

PURPOSE/HYPOTHESIS

The aim was to investigate whether the healing and remodeling of an FLA were affected by the use of a mesh by comparing the signal intensity of an FLA-alone group vs an FLA + Mesh group on postoperative magnetic resonance imaging (MRI). The hypothesis was that the use of a mesh would decrease the MRI signal intensity of FLA during the early postoperative phase.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who had undergone SCR using an FLA with or without a mesh between March 2013 and August 2021 were retrospectively analyzed. Follow-up MRI was performed at 3 months. A total of 78 patients (24 in the FLA group and 54 in the FLA + Mesh group) with intact grafts were included. Graft remodeling was evaluated by analyzing the signal-to-noise quotient (SNQ) at the humeral, mid-substance, and glenoid sites. Theoretically, lower SNQ ratios indicate higher strength and better healing of the graft.

RESULTS

The mean SNQ was 30.603 (range, 11.790-72.710) in the FLA group and 18.367 (range, 4.464-69.500) in the FLA + Mesh group (P < .001). Furthermore, significant differences were found between the 2 groups at the humeral and mid-substance sites (37.863 [range, 5.092-81.187] vs 15.512 [range, 1.814-80.869], P < .001; and 29.168 [range, 6.103-73.900] vs 16.878 [range, 2.454-92.416], P = .003; respectively). However, there was no difference between the 2 groups at the glenoid site (25.346 [range, 7.565-86.353] vs 20.354 [range, 3.732-88.468], P = .057).

CONCLUSION

At the 3-month follow-up, the FLA + Mesh group showed a lower MRI signal intensity than the FLA group. The healing and remodeling of an FLA may be enhanced when a mesh is used.

Time required to achieve clinically significant outcomes after arthroscopic superior capsular reconstruction

PURPOSE

To investigate the time-dependent nature of clinically significant outcomes, including the minimal clinically important difference (MCID), substantial clinical benefit, and Patient Acceptable Symptomatic State (PASS) after arthroscopic superior capsular reconstruction, and the factors contributing to the achievement of early clinically significant outcomes.

METHODS

Patients who underwent ASCR between March 2015 and September 2020 with complete preoperative and postoperative 6-month, 1-year, and 2-year patient-reported outcome measures (PROMs) were retrospectively analysed. Threshold values for MCID, substantial clinical benefit, and PASS were obtained from the previous literature for the PROMs. The time required to achieve clinically significant outcomes was calculated using Kaplan-Meier analysis. Multivariate Cox regression was performed to evaluate the variables predictive of an earlier or delayed achievement of MCID.

RESULTS

Fifty-nine patients with a mean age of 64.5 ± 8.7 years old were included. The time of mean achievement of MCID, substantial clinical benefit, and PASS for VAS was 11.2 ± 0.9, 16.3 ± 1.1, and 16.6 ± 0.9 months, respectively. The time of mean achievement of MCID, substantial clinical benefit, and PASS for ASES was 13.2 ± 1.0, 16.8 ± 1.0, and 18.3 ± 0.9 months, respectively. The time of mean achievement of MCID, substantial clinical benefit, and PASS for the Constant score was 11.6 ± 0.9, 15.1 ± 1.0, and 14.7 ± 0.9 months, respectively. The time of mean achievement of MCID, substantial clinical benefit, and PASS for SANE was 14.4 ± 1.0, 16.1 ± 1.0, and 15.5 ± 0.8 months, respectively. Patients with a higher preoperative VAS score achieved an earlier MCID for VAS (P = 0.014). However, patients with a higher preoperative ASES and SANE scores achieved delayed MCID for ASES and SANE (P = 0.026, and P < 0.001, respectively).

CONCLUSION

Most patients achieved MCIDs around 1 year after arthroscopic superior capsular reconstruction. A higher preoperative VAS score favours faster MCID achievement, while higher preoperative ASES and SANE scores contribute to delayed MCID achievement.

STUDY DESIGN

Cohort study LEVEL OF EVIDENCE: Level IV.

Postoperative MRI signal intensity correlates functional outcomes after superior capsular reconstruction

PURPOSE

Superior capsular reconstruction (SCR) using fascia lata autograft has been performed for irreparable rotator cuff tear recently. The signal-to-noise quotient (SNQ) of the graft on magnetic resonance imaging (MRI) may reflect the degree of graft maturity and healing. However, how SNQ changes with graft remodelling and time and whether this change correlates with postoperative clinical outcomes after SCR remain unknown. This study aimed to explore the correlation between SNQ of the fascia lata autograft and clinical functional outcomes after SCR.

METHODS

Patients with irreparable posterosuperior rotator cuff tear undergoing SCR using fascia lata autograft between 2013 and 2017 were retrospectively analysed. For clinical outcomes, the American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score, Single Assessment Numeric Evaluation (SANE), and Visual Analogue Scale (VAS) for pain and range of motion (ROM; forward flexion and external rotation) were evaluated at postoperative 6 and 12 months. Signal intensity of the humeral, mid-substance, and glenoid sites and background were measured to calculate the SNQ values on follow-up MRI at 3 and 12 months. The correlations between clinical outcomes and SNQ at different time points were then analysed.

RESULTS

A total of 15 patients were enrolled in the study. The mean postoperative VAS score significantly increased at postoperative 6 months and significantly decreased at postoperative 12 months. Except for forward flexion, all other functional outcomes were improved at postoperative 6 months. Analysis of MRI showed SNQ at the humeral (SNQh), mid-substance, and glenoid sites decreased from postoperative 3 to 12 months with a statistical significance detected in SNQh (P < 0.01). Correlation analyses showed that the SNQh values negatively correlated with VAS, ASES, Constant-Murley score, SANE, ROM (forward flexion), and ROM (external rotation) (all P < 0.05).

CONCLUSION

SNQ of the fascia lata autograft decreased with time in patients receiving SCR. SNQ at the humeral site was negatively correlated with clinical outcomes.

LEVEL OF EVIDENCE

III.

Superior Capsular Reconstruction Combined With Lower Trapezius Tendon Transfer Improves the Biomechanics in Posterosuperior Massive Rotator Cuff Tears

BACKGROUND

Surgical treatments for chronic posterosuperior massive rotator cuff tear (MRCT) are still controversial. Superior capsular reconstruction (SCR), which provides a static stabilizer to decrease superior humeral head translation, and lower trapezius tendon transfer (LTTT) with centralization of the humeral head, which prevents superior humeral head migration, are potential surgical options. To date, SCR combined with LTTT has not been fully investigated.

HYPOTHESIS

Restoration of static stabilizer and dynamic stabilizer together would effectively improve shoulder kinematics in posterosuperior MRCT.

STUDY DESIGN

Controlled laboratory study.

METHODS

A custom-made shoulder mechanics testing system was used to test 8 fresh-frozen cadaveric shoulders. The testing conditions were as follows: (1) intact; (2) posterosuperior MRCT (supraspinatus and infraspinatus removed); (3) SCR using the fascia lata; (4) LTTT; and (5) SCR combined with LTTT. The total rotational range of motion (ROM), superior translation, anteroposterior translation, and peak subacromial contact pressure were evaluated at 0°, 30°, and 60° of shoulder abduction. Repeated-measures analysis of variance and Tukey post hoc tests were performed.

RESULTS

The total rotational ROM, superior translation, anteroposterior translation, and peak subacromial contact pressure increased in posterosuperior MRCTs (all, P < .05). The rotational ROM, superior translation, anteroposterior translation, and peak subacromial contact pressure at 0° and 30° of shoulder abduction decreased in SCR (all, P < .05). However, there was no significant improvement in rotational ROM, superior translation, and peak subacromial contact pressure at 60° of shoulder abduction (P > .05). LTTT resulted in a significant decrease in the superior translation, anteroposterior translation, and peak subacromial contact pressure at 0°, 30°, and 60° of shoulder abduction (P < .05). SCR combined with LTTT restored the total rotational ROM, superior translation, anteroposterior translation, and peak subacromial contact pressure at 0°, 30°, and 60° of shoulder abduction (all, P < .05).

CONCLUSION

In the cadaveric model, SCR combined with LTTT showed improved shoulder kinematics and contact pressures in the posterosuperior MRCT model compared with SCR or LTTT alone.

CLINICAL RELEVANCE

SCR combined with LTTT may be regarded as an alternative surgical procedure for posterosuperior MRCTs.

Clinical and Radiological Outcomes of Arthroscopic Superior Capsular Reconstruction Versus Primary Rotator Cuff Repair in Massive Rotator Cuff Tears: A Propensity Score-Matched Study

BACKGROUND

Arthroscopic superior capsular reconstruction (aSCR) has emerged as a treatment option for managing massive rotator cuff tears (MRCTs) given the unpredictable results after an arthroscopic rotator cuff repair (aRCR). Yet, few comparative studies of aSCR and aRCR have been conducted.

PURPOSE

To compare the clinical and radiological outcomes between aRCR and aSCR in patients with MRCT.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 163 cases of MRCT from 2010 to 2020 with follow-up ≥2 years were retrospectively reviewed. Among them, 102 had aRCR and 61 had aSCR using fascia lata autograft. Propensity score matching was used to select controls matched for age, sex, diabetes mellitus, osteoporosis, preoperative American Shoulder and Elbow Surgeons score, Single Assessment Numeric Evaluation score, Constant score, pain visual analog scale (pVAS) score, range of motion (ROM), tear size, global fatty degeneration index, and acromiohumeral distance (AHD). Last, 33 cases in each group were selected after propensity score matching. Radiological assessment was conducted using serial postoperative magnetic resonance imaging. Pre- and postoperative findings-including American Shoulder and Elbow Surgeons, pVAS, Single Assessment Numeric Evaluation, and Constant scores and ROM-were assessed to compare clinical outcomes. For radiological outcomes, global fatty degeneration index, AHD, and healing rate were evaluated. Healing failure was defined as Sugaya classification IV or V in the aRCR group, as compared with a full-thickness tear of the graft in the aSCR group, which corresponded to Sugaya classification IV or V.

RESULTS

Postoperative clinical outcomes were significantly improved at the final follow-up in both groups. In the aSCR group, postoperative forward flexion, pVAS, and AHD were significantly improved as compared with the aRCR group (mean, 161° vs 148° [P = .02]; 1.03 vs 1.64 [P = .047]; 7.00 vs 5.23 mm [P < .001], respectively). The healing rate was 20 of 33 (60.6%) for aRCR and 29 of 33 (87.9%) for aSCR (P = .022).

CONCLUSION

aSCR and aRCR are effective and reliable treatment options for MRCT. However, when compared with aRCR, aSCR showed improved clinical outcomes, including pVAS score, postoperative ROM, and favorable radiological findings, including AHD and a higher healing rate.

Does body mass index affect outcomes following arthroscopic superior capsular reconstruction using fascia lata autograft for massive irreparable rotator cuff tear?

PURPOSE

This study aimed to evaluate the effect of increased body mass index (BMI) on patient-reported outcomes (PROs) and clinically significant outcomes (CSOs) obtained > two years postoperatively following arthroscopic superior capsular reconstruction (ASCR).

METHODS

A retrospective study was conducted on patients who underwent ASCR with a minimum two year follow-up. All patients were divided into normal (BMI < 25.0), overweight (BMI 25-30.0), and obese (BMI ≥ 30) according to preoperative BMI. Patients were assessed using the PROs preoperatively and at six months, one year, and two years postoperatively, including the visual analog scale (VAS), American Shoulder and Elbow Surgeons (ASES), and Constant-Murley scores. The time required to achieve each CSO was analyzed and compared. Multivariate analyses evaluated the predictor variables and time required to achieve CSOs.

RESULTS

This study included 63 patients with a mean age of 64.8 ± 8.6 years, including 31 normal BMI, 25 overweight, and seven obese patients. Significant improvements in VAS and ASES scores after ASCR were observed in all three groups. Normal and overweight patients had significant improvements in the Constant score; however, no difference was observed in obese patients. No significant difference was observed in the probability distributions of CSOs between the BMI groups. Similarly, no significant differences were observed in the probability distributions of the CSOs, ASES, and Constant scores at each time point, among the BMI groups.

CONCLUSION

Patients in the normal and overweight groups had significant improvements in the VAS, ASES, and Constant scores after ASCR. Patients in the obese group had a significant improvement in VAS score; however, there is no difference for the ASES and Constant scores in the obese group. However, no differences were observed in all PROMs and the likelihood of achieving CSOs among the different BMI groups.

Regulatory effect of electroacupuncture at auriculo-body acupoints on the functions of the biliary system and actions of the vagus nerve

AIM: To study the mechanism of electroacupuncture at auriculo-body acupoints in treating disorders of the biliary system and the actions of the vagus nerve in regulating biliary functions.

METHODS: A rabbit model of common bile duct stones was created. The influence of the vagus nerve on the functions of the biliary system was evaluated using bile current capacity, biliary duct pressure, and Oddi sphincter myoelectricity. The changes in these parameters were observed after electroacupuncture at a frequency of 20 Hz for 30 minutes at "Yi-Dan" area, Auriculo-acupoint and "Danshu".

RESULTS: A pathological increase in bile current capacity, biliary duct pressure, and Oddi sphincter myoelectricity was observed in rabbits with common bile duct stones. Oddi sphincter myoelectricity was transformed from orderly electric discharge into disorder and paroxysmal discharge. Electroacupuncture at ear-body acupoints further increased bile current capacity. The myotensity of the Oddi sphincter was decreased and myoelectricity was restored into rhythmicity. The regulatory effect of electroacupuncture at ear-body acupoints on biliary duct functions was not obvious in rabbits whose vagus nerve was removed. Increased bile current capacity and reduced biliary duct pressure were observed 30 minutes after stopping electroacupuncture.

CONCLUSION: The integrity of the vagus nerve is necessary for maintaining the normal functions of the biliary system in rabbits. Electroacupuncture at ear-body acupoints regulates biliary duct function mainly through modulating the vagus nerve.

Alleviating sleep disturbances and modulating neuronal activity after ischemia: Evidence for the benefits of zolpidem in stroke recovery

AIMS

Sleep disorders are prevalent among stroke survivors and impede stroke recovery, yet they are still insufficiently considered in the management of stroke patients, and the mechanisms by which they occur remain unclear. There is evidence that boosting phasic GABA signaling with zolpidem during the repair phase improves stroke recovery by enhancing neural plasticity; however, as a non-benzodiazepine hypnotic, the effects of zolpidem on post-stroke sleep disorders remain unclear.

METHOD

Transient ischemic stroke in male rats was induced with a 30-minute middle cerebral artery occlusion. Zolpidem or vehicle was intraperitoneally delivered once daily from 2 to 7 days after the stroke, and the electroencephalogram and electromyogram were recorded simultaneously. At 24 h after ischemia, c-Fos immunostaining was used to assess the effect of transient ischemic stroke and acute zolpidem treatment on neuronal activity.

RESULTS

In addition to the effects on reducing brain damage and mitigating behavioral deficits, repeated zolpidem treatment during the subacute phase of stroke quickly ameliorated circadian rhythm disruption, alleviated sleep fragmentation, and increased sleep depth in ischemic rats. Immunohistochemical staining showed that in contrast to robust activation in para-infarct and some remote areas by 24 h after the onset of focal ischemia, the activity of the ipsilateral suprachiasmatic nucleus, the biological rhythm center, was strongly suppressed. A single dose of zolpidem significantly upregulated c-Fos expression in the ipsilateral suprachiasmatic nucleus to levels comparable to the contralateral side.

CONCLUSION

Stroke leads to suprachiasmatic nucleus dysfunction. Zolpidem restores suprachiasmatic nucleus activity and effectively alleviates post-stroke sleep disturbances, indicating its potential to promote stroke recovery.

Improved Acromiohumeral Distance Independently Predicts Better Outcomes After Arthroscopic Superior Capsular Reconstruction Graft Tears

PURPOSE

To identify independent factors responsible for poor outcomes after a graft tear after arthroscopic superior capsular reconstruction (ASCR).

METHODS

Patients who underwent ASCR for massive rotator cuff tears between January 2013 and July 2021were reviewed. On the basis of the achievement of the minimal clinically important differences for clinical outcome measures at the final follow-up, patients were divided into the good outcome (GO) and poor outcome (PO) groups. The minimal clinically important differences were calculated as the value equal to one-half of the standard deviation of the changes in outcome scores between the preoperative baseline and the latest follow-up. Pre- and final follow-up variables included demographics, American Shoulder and Elbow Surgeons score, Constant score, visual analog scale score, and range of motion. Preoperative and postoperative 1-year radiologic variables were analyzed using magnetic resonance imaging, including anteroposterior and mediolateral tear sizes, subscapularis tear, acromiohumeral distance (AHD), and degree of fatty degeneration. Logistic regression analysis was performed to identify the significant predictors of poor outcomes.

RESULTS

A total of 33 patients who underwent ASCR presented with graft tears, which were confirmed by postoperative 1-year magnetic resonance imaging, and had a minimum follow-up duration of 2 years after surgery were enrolled. The GO group demonstrated significantly greater improvements in functional outcomes compared with the PO group (American Shoulder and Elbow Surgeons score: 83.5 ± 11.8 vs 64.0 ± 20.4, P = 0.004; Constant: 67.6 ± 5.7 vs 57.1 ± 9.8, P < .001; and visual analog scale score: 0.9 ± 1.2 vs 2.4 ± 2.0, P = .026). The postoperative 1-year AHD showed significant improvement in the GO group (3.1 ± 1.2 vs 6.1 ± 1.4, P < .001) but no change in the PO group (3.4 ± 1.3 vs 4.2 ± 0.9, P = .074) postoperatively. Multivariate logistic regression analysis indicated that a decreased postoperative 1-year AHD (odds ratio, 0.145; P = .019) was associated with a poor outcome after a graft tear.

CONCLUSIONS

A narrow postoperative 1-year AHD was identified as the most important independent risk factor indicating poor clinical outcomes after a graft tear post-ASCR, which was related to a larger tear and loss of integrity between the grafts and infraspinatus at 1-year postoperatively.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.