Patient experience of head and neck lymphedema therapy: a qualitative study

Prognostic Factors and Outcomes Associated With Neck Lymphedema in Head and Neck Cancer Survivors

OBJECTIVES

The purpose of this study is to determine the predictors of neck lymphedema and to explore its association with symptoms and patient-reported outcomes (PROs) in Head and Neck Cancer (HNC) patients who underwent non-operative treatment.

METHODS

This study involved a cross-sectional secondary analysis of data from patients diagnosed with head and neck squamous cell carcinoma who underwent radiation therapy (±chemotherapy). Patients with visits <6 weeks or >2 years following completion of radiation and those with recurrent or metastatic cancer were excluded. Presence of post-treatment lymphedema, demographics, clinical characteristics, health-related behaviors, and symptoms were collected. PROs were obtained using validated questionnaires that assessed depression, anxiety, swallowing dysfunction, and quality of life (QOL). Multivariable regression models were used to examine the relationship between lymphedema with predictors and symptoms.

RESULTS

Of the 203 patients included, 88 (43.4%) developed post-treatment lymphedema. In multivariable analysis, pre-treatment Body Mass Index (BMI) (odds ratio [OR] = 1.07, 95% confidence interval [CI] [1.01, 1.14] p = 0.016) and N stage (OR = 1.96, 95% CI [1.06, 3.66], p = 0.032) were found to be independently associated with lymphedema. Regarding PROs, lymphedema was associated with greater swallowing dysfunction (3.48, 95% CI [0.20, 6.75], p = 0.038), decreased mouth opening (-3.70, 95% CI [-7.31, -0.10], p = 0.044), and increased fatigue (1.88, 95% CI [1.05, 3.38], p = 0.034).

CONCLUSION

Higher pre-treatment BMI and greater N stage are identified as independent predictors for lymphedema development in non-operative HNC patients. Additionally, patients experiencing lymphedema reported worsening swallowing dysfunction and increased symptoms related to trismus and fatigue. Recognizing patients at elevated risk for lymphedema allows for early intervention, alleviation of symptom burden, and optimization of health care resources.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:3656-3663, 2024.

Managing lymphoedema following treatment for head and neck cancer: is complete decongestive therapy an effective intervention to improve dysphagia outcomes?

PURPOSE OF REVIEW

The purpose of this review is to summarize current evidence regarding management of head and neck lymphoedema (HNL) to improve dysphagia outcomes following head and neck cancer (HNC) treatment. This review aims to support complete decongestive therapy (CDT) comprising compression, manual lymphatic drainage (MLD), exercises and skincare as an adjunct of dysphagia rehabilitation.

RECENT FINDINGS

Research in the limbs supports the use of CDT to improve lymphoedema outcomes. Emerging evidence supports the use of CDT for the head and neck, though, there is no consensus on optimal treatment required to improve dysphagia outcomes. Current evidence is limited due to a paucity of randomized controlled trials, case series or cohort studies with small participant numbers, and a lack of functional and instrumental dysphagia outcome measures. This provides a foundation to design and test an individually tailored programme of HNL intervention to evaluate swallowing outcomes post CDT.

SUMMARY

As the incidence of HNC is increasing with HPV, with patients living for longer with late effects of HNC treatment, it is vital to understand how the presence of HNL impacts on the swallow, and if functional dysphagia outcomes improve following treatment of HNL. Prospective, longitudinal research with objective and functional outcome measures are required to help determine optimal management of HNL and its impact on the swallow.

Determining risk and predictors of head and neck cancer treatment-related lymphedema: A clinicopathologic and dosimetric data mining approach using interpretable machine learning and ensemble feature selection

Background and purpose

The ability to determine the risk and predictors of lymphedema is vital in improving the quality of life for head and neck (HN) cancer patients. However, selecting robust features is challenging due to the multicollinearity and high dimensionality of radiotherapy (RT) data. This study aims to overcome these challenges using an ensemble feature selection technique with machine learning (ML).

Materials and methods

Thirty organs-at-risk, including bilateral cervical lymph node levels, were contoured, and dose-volume data were extracted from 76 HN treatment plans. Clinicopathologic data was collected. Ensemble feature selection was used to reduce the number of features. Using the reduced features as input to ML and competing risk models, internal and external lymphedema prediction capability was evaluated with the ML models, and time to lymphedema event and risk stratification were estimated using the risk models.

Results

Two ML models, XGBoost and random forest, exhibited robust prediction performance. They achieved average F1-scores and AUCs of 84 ± 3.3 % and 79 ± 11.9 % (external lymphedema), and 64 ± 12 % and 78 ± 7.9 % (internal lymphedema). Predictive ML and risk models identified common predictors, including bulky node involvement, high dose to various lymph node levels, and lymph nodes removed during surgery. At 180 days, removing 0-25, 26-50, and > 50 lymph nodes increased external lymphedema risk to 72.1 %, 95.6 %, and 57.7 % respectively (p = 0.01).

Conclusion

Our approach, involving the reduction of HN RT data dimensionality, resulted in effective ML models for HN lymphedema prediction. Predictive dosimetric features emerged from both predictive and competing risk models. Consistency with clinicopathologic features from other studies supports our methodology.

Rehabilitation Interventions for Head and Neck Cancer-Associated Lymphedema: A Systematic Review

Importance

Head and neck cancer-associated lymphedema (HNCaL) affects up to 90% of survivors of head and neck cancer and is a substantial contributor to disability following head and neck cancer treatment. Despite the prevalence and morbidity associated with HNCaL, rehabilitation interventions are not well studied.

Objective

To identify and appraise the current evidence for rehabilitation interventions in HNCaL.

Evidence Review

Five electronic databases were searched systematically from inception to January 3, 2023, for studies on HNCaL rehabilitation interventions. Study screening, data extraction, quality rating, and risk of bias assessment were performed by 2 independent reviewers.

Findings

Of 1642 citations identified, 23 studies (1.4%; n = 2147 patients) were eligible for inclusion. Six studies (26.1%) were randomized clinical trials (RCTs) and 17 (73.9%) were observational studies. Five of the 6 RCTs were published during 2020 to 2022. Most studies had fewer than 50 participants (5 of 6 RCTs; 13 of 17 observational studies). Studies were categorized by intervention type, including standard lymphedema therapy (11 studies [47.8%]) and adjunct therapy (12 studies [52.2%]). Lymphedema therapy interventions included standard complete decongestive therapy (CDT) (2 RCTs, 5 observational studies), modified CDT (3 observational studies), therapy setting (1 RCT, 2 observational studies), adherence (2 observational studies), early manual lymphatic drainage (1 RCT), and inclusion of focused exercise (1 RCT). Adjunct therapy interventions included advanced pneumatic compression devices (APCDs) (1 RCT, 5 observational studies), kinesio taping (1 RCT), photobiomodulation (1 observational study), acupuncture/moxibustion (1 observational study), and sodium selenite (1 RCT, 2 observational studies). Serious adverse events were either not found (9 [39.1%]) or not reported (14 [60.9%]). Low-quality evidence suggested the benefit of standard lymphedema therapy, particularly in the outpatient setting and with at least partial adherence. High-quality evidence was found for adjunct therapy with kinesio taping. Low-quality evidence also suggested that APCDs may be beneficial.

Conclusions and Relevance

The results of this systematic review suggest that rehabilitation interventions for HNCaL, including standard lymphedema therapy with kinesio taping and APCDs, appear to be safe and beneficial. However, more prospective, controlled, and adequately powered studies are needed to clarify the ideal type, timing, duration, and intensity of lymphedema therapy components before treatment guidelines can be established.

Traditional risk factors and nodal yield-still relevant with high-quality risk-adapted adjuvant treatment for locally advanced head and neck cancer?

OBJECTIVE

Patients with locally advanced head and neck cancer (LAHNC) often undergo multimodal therapy including radical resection of the primary tumor and neck dissection (ND) followed by risk-adapted adjuvant radio(chemo)therapy (R(C)T). Quality parameters influencing local control and survival of these patients have been postulated: resection status (R status), extranodal extension (ENE), interval to adjuvant treatment ≤6 weeks, R(C)T given when indicated, and nodal yield (NY) ≥18 lymph nodes per neck. For other solid tumors the trend is towards less extensive lymph node surgery to avoid toxicity such as lymphedema, damage to peripheral nerves, dysesthesia, or paresthesia. The present study aims to investigate whether the number of nodes removed during neck dissection for LAHNC is still predictive for outcome when patients receive risk-adapted adjuvant treatment according to current guidelines.

METHODS

Between 2008 and 2015, 468 patients with LAHNC undergoing R(C)T with curative intent were prospectively registered in a database (UICC III/IV). Among them, 359 patients received adjuvant treatment and 295 underwent neck dissection. There were 119 (40%) patients with an oropharyngeal primary, 49 (17%) with cancer of the larynx/hypopharynx, 88 (30%) of the oral cavity, and 39 (13%) of the nasal/paranasal sinuses and cancer of unknown primary (CUP). Median follow-up was 45.6 months. Histopathology revealed an R1 status in 65 (22%) cases and ENE in 93 (31%) cases. 150 (51%) patients received RCT; the median time to adjuvant treatment from the day of tumor resection was 44 days (35-54) and overall treatment time (OTT; time from surgery to the last day of R(C)T) was 90 days (82-101). Factors influencing disease-free survival (DFS) were adjusted and analyzed using CART analysis (removed nodes, number of positive nodes, body mass index (BMI), ENE, T and N classification, R status, and primary site). Local control (LC), distant metastases-free survival (DMFS), and overall survival (OS) were analyzed using Kaplan-Meier statistics and multivariate analysis (MVA) for factors predictive for DFS and OS.

RESULTS

CART analysis (Classification and Regression Trees) showed that T classification (T3/4) is the most important predictor for DFS, followed by age (> 61 years) and BMI (< 17.4). Primary site (OPC vs. other) and number of removed nodes (< 17) were shown to be less important for DFS, while ECE, N classification, and R status seem to be of little relevance. MVA revealed number of positive nodes, non-OPC, and T3/4 to be negative predictive factors for DFS. For OS, the number of positive nodes and non-OPC primary were predictive. Five-year rates were 86.1% for LC, 87.9% DMFS, 76.5% DFS, and 67.2% for OS.

CONCLUSION

In this patient cohort, the number of removed nodes is not relevant for DFS and OS, while the number of positive nodes and T classification have a negative impact on these endpoints. The high-risk factors positive resection margin and ECE seem to lose their negative impact on DFS and OS. High-quality care in head and oncology is only possible within a close multidisciplinary team and network.

Validity Testing of the Head and Neck Lymphedema and Fibrosis Symptom Inventory

Background: Lack of reliable and valid tools significantly impacts early identification and timely treatment of lymphedema and fibrosis (LEF) in the head and neck cancer population. To address this need, we developed and reported a patient-reported outcome measure (Head and Neck Lymphedema and Fibrosis Symptom Inventory [HN-LEF SI]). This article reports the construct validity (convergent and divergent validity) testing of the tool. Materials and Methods: A prospective, longitudinal, instrument validation study was conducted in patients with a newly diagnosed oral cavity or oropharyngeal cancer. Participants completed the HN-LEF SI and six carefully selected self-report measures at pretreatment, end-of-treatment, and every 3 months up to 12 months after treatment. Spearman correlations were used. Results: A total of 117 patients completed the study. Patterns of correlations of the HN-LEF SI scores with the established self-report measure scores were consistent with expected convergent and divergent validity. Conclusion: Evidence from this work supports the construct validity of the HN-LEF SI.

Patient and physiotherapist perceptions of the Getting Recovery Right After Neck Dissection (GRRAND) rehabilitation intervention: a qualitative interview study embedded within a feasibility trial

OBJECTIVE

The Getting Recovery Right After Neck Dissection (GRRAND) intervention is a physiotherapy programme for patients with head and neck cancer who have undergone neck dissection. The aim of this qualitative study was to understand if the intervention was useful, acceptable and whether it was feasible to conduct a randomised controlled trial (RCT).

DESIGN

This qualitative study was embedded within the GRRAND-Feasibility (GRRAND-F) Study.

SETTING

Participants were recruited from four acute National Health Service hospitals in England between 2020 and 2021.

PARTICIPANTS

We interviewed four usual care and four intervention patient-participants from a single study site (Oxford). Six were male, two were female. All were white British ethnicity. We interviewed two physiotherapists from Oxford who delivered the GRRAND-F intervention, and physiotherapists from Birmingham, Poole and Norwich who were trained to deliver the intervention but were not able to deliver it within the study time frame.

RESULTS

The analysis identified five themes: (1) Acceptability, (2) Adherence, (3) Outcomes, (4) Feasibility and (5) Stand-alone themes (prehabilitation, video consultations, healthcare use).Patient-participants and physiotherapist-participants agreed that usual care was not meeting patients' rehabilitation needs. The GRRAND intervention provided biopsychosocial support. In comparison to the usual care group, patient-participants who received the intervention were more confident that they could perform rehabilitation exercises and were more motivated to engage in long-term adaptive behaviour change. Physiotherapists felt they needed more administrative support to participate in an RCT.

CONCLUSION

Participants felt that usual care was insufficient. GRRAND provided much needed, biopsychosocial support to patients. Participants were supportive that it would be feasible to test GRRAND in an RCT.

TRIAL REGISTRATION NUMBER

ISRCTN11979997.

The efficacy of Kinesio taping on lymphedema following head and neck cancer therapy: a randomized, double blind, sham-controlled trial

OBJECTIVE

The aim was to investigate the effectiveness of Kinesio taping for lymphedema following head and neck cancer therapy and its effect on patient compliance and quality of life.

METHODS

A total of 66 patients with lymphedema following head and neck cancer therapy were randomly allocated to the therapeutic Kinesio taping group (n = 33) and the sham Kinesio taping group (n = 33). All participants received manual lymphatic drainage, Kinesio taping, and home exercises for the first four weeks, and only home exercises for the second four weeks. The tape measurements, a scale of external lymphedema, a scale of the internal lymphedema, and quality of life were evaluated in both groups. The perceived discomfort consisting of limitation of daily living activities, pain, tightness, stiffness, and heaviness were also recorded.

RESULTS

When the group x time effect was evaluated, it was observed that external lymphedema was significantly reduced in both groups according to neck and face composite measurements (p < .001). However, in these measurements, a significant difference was found between the groups in favor of the KT group (p = .001, p = .032, respectively). At the end of the study, there was no significant difference in terms of internal lymphedema in both groups (p = .860). The quality of life parameters such as global health status and swallowing were significantly better in the Kinesio taping group (p < .001). There was no significant difference in the parameters of perceived discomfort between the two groups (p = .282, p = .225, p = .090, p = .155, p = .183, respectively).

CONCLUSION

Kinesio taping is effective in tape measurements and positively affects the quality of life in lymphedema following head and neck cancer therapy.

Head and neck lymphoedema-research challenges during the COVID-19 pandemic

Management of secondary head and neck lymphoedema has undergone little research investigation. Its treatment is time and labour intensive and involves multiple therapeutic modalities without a clear understanding of which is most effective. This study aimed to determine the feasibility of a randomised controlled trial comparing two therapeutic modalities to manage head and neck lymphoedema. The secondary objective was to evaluate the clinical effects of these treatments. Participants were randomised to receive treatment with manual lymphatic drainage or compression over 6 weeks, with the primary outcome-percentage tissue water-measured 12 weeks after treatment. Six participants were recruited until the study was ceased due to restrictions imposed by the COVID-19 pandemic. Some 86% of required attendances were completed. Percentage tissue water increased in all participants at 12 weeks. No consistent trends were identified between internal and external lymphoedema. The small number of people recruited to this study informs its feasibility outcomes but limits any conclusions about clinical implications.

Photobiomodulation Therapy in Head and Neck Cancer-Related Lymphedema: A Pilot Feasibility Study

Purpose:

Lymphedema is a common debilitating late effect among patients post-head and neck cancer (HNC) treatment. Head and neck lymphedema was associated with symptom burden, functional impairment, and decreased quality of life. The objective of this study was to determine the feasibility and potential efficacy of the use of photobiomodulation (PBM) therapy for head and neck lymphedema, symptom burden, and neck range of motion among HNC survivors.

Methods:

This was a single-arm, pre- and post-design clinical trial. Eligible patients included those with lymphedema after completion of complete decongestive therapy (CDT) and 3 to 18 months after completion of cancer therapy. The intervention included PBM therapy 2 times a week for 6 weeks for a total of 12 treatments. Lymphedema, symptom burden, and neck range of motion were measured at baseline, end-of-intervention, and 4-week post-intervention.

Results:

Of the 12 patients enrolled in the study, 91.7% (n = 11) completed the study intervention and assessment visits, and no adverse events were reported. When comparing the baseline to 4-week post-intervention, we found statistically significant improvements in the severity of external lymphedema, symptom burden, and neck range of motion (all P < .05).

Conclusion:

PBM therapy was feasible and potentially effective for the treatment of head and neck lymphedema. Future randomized controlled trials are warranted to examine the efficacy of PBM therapy for HNC-related lymphedema.

Trial Registration Number and Date of Registration:

ClinicalTrials.gov Identifier: NCT03738332; date of registration: November 13, 2018.

Edemas of the face and lymphoscintigraphic examination

Facial edemas not secondary to surgery and/or radiotherapy for head and neck cancer are relatively uncommon. Our aim is to report a retrospective analysis of the lymphoscintigraphic and SPECT-CT investigations obtained in patients with such facial edema. Retrospective review of exams (planar imagings in all and with SPECT-CT in 5) obtained after the subcutaneous injection of 99mTc HSA Nanosized colloids between the eyebrows in five men and seven women. Four main lymphatic pathways were identified on sequential planar imagings: para-nasal left and right and supra- ocular left and right. For eleven patients, the absence of visualization of lymphatic drainage and/or their delayed appearance correlated well with the localisation of the edematous areas. In two patients with post-traumatic and post- surgical edemas, SPECT-CT showed one deep left sided cervical lymph node (LN) in front of the first cervical vertebra. This lymphoscintigraphic approach represents a simple and valuable way to assess the lymphatic drainage pathways of the face and to establish the diagnosis of facial lymphedema.

Prognostic factors for lymphedema in patients with locally advanced head and neck cancer after combined radio(chemo)therapy- results of a longitudinal study

AIM

Treatment-associated lymphedema is a common side effect after multimodal therapy for locally advanced head and neck cancer (LAHNC). This study aims to evaluate potential prognostic factors for head and neck lymphedema (HNL) and its potential impact on clinical outcome.

METHODS

This is a prospective data registry analysis on 280 patients treated for locally advanced head and neck cancer (LAHNC). All patients received surgery and risk-adapted platinum-based adjuvant intensity modulated radio(chemo)therapy (R(C)T, IMRT). Treatment- related toxicity was prospectively registered in a data base in regular intervals (baseline 3 months after R(C)T, every 3 months for 3 years, and every 6 months thereafter) and documented according to RTOG/EORTC toxicity criteria.

RESULTS

Predictive for any grade HNL 3 months after R(C)T were age, BMI, number of removed nodes and RT modality. Multivariable logistic regression analysis showed that in the acute toxicity phase (3 months after R(C)T) higher body mass index (BMI), extracapsular spread (ECE), linac-based IMRT, bilateral treatment to the neck (surgery and RT), and the addition of chemotherapy increase the risk for grade 2 HNL. For chronic HNL, higher BMI, linac-based IMRT and ECE were predictive for grade 2 HNL. Higher BMI is associated with better local control rates. Advanced age and ECE had a negative impact on OS.

CONCLUSION

HNL is a common acute and late side effect after multimodal therapy for LAHNC. Knowing risk factors for HNL prior to therapy enables caregivers and patients to take measures prior to treatment to prevent or limit the effects of HNL.

Advanced pneumatic compression for treatment of lymphedema of the head and neck: a randomized wait-list controlled trial

PURPOSE

Lymphedema associated with head and neck cancer (HNC) therapy causes adverse clinical outcomes. Standard treatment includes professionally administered complete decongestive therapy (CDT). Cost and availability of trained therapists are known barriers to therapy. Advanced pneumatic compression devices (APCD) may address these issues. A randomized, wait-list controlled trial was undertaken to evaluate an APCD in post-treatment HNC patients with lymphedema.

MATERIAL AND METHODS

Eligible patients had completed treatment for HNC, were disease free, and had lymphedema at enrollment. Participants were randomized to wait-list lymphedema self-management (standard of care) or lymphedema self-management plus the use of the APCD bid. Safety (CTCAE V4.0) and feasibility were primary endpoints; secondary endpoints included efficacy measure by objective examination and patient reported outcomes (symptoms, quality of life, function), adherence barriers, and satisfaction. Assessments were conducted at baseline and weeks 4 and 8.

RESULTS

Forty-nine patients were enrolled (wait-list n = 25; intervention n = 24). In total, forty-three patients completed the study. No device-related Serious Adverse Events were reported. Most patients used the APCD once per day, instead of the prescribed twice per day, citing time related factors as barriers to use. APCD use was associated with significant improvement in perceived ability to control lymphedema (p = 0.003) and visible external swelling (front view p < 0.001, right view p = 0.004, left p = 0.005), as well as less reported pain.

CONCLUSION

This trial supports the safety and feasibility of the APCD for the treatment of secondary lymphedema in head and neck cancer patients. In addition, preliminary data supports efficacy.

Self-care for head and neck cancer survivors with lymphedema and fibrosis: study protocol for a randomized controlled trial

BACKGROUND

Head and neck cancer (HNC) patients are at high risk for developing lymphedema and fibrosis (LEF) following cancer treatment. Once HNC patients develop LEF, they need to conduct life-long self-care to slow LEF progression and reduce associated symptom burden and functional deficits. Data demonstrate that inadequate LEF self-care may be a potentially remediable issue. The objective of this study is to explore the feasibility and preliminary efficacy of an Information-Motivation-Behavioral (IMB) Skills model-driven self-care program (SCP) to improve LEF management and reduce LEF-related symptom burden and functional impairments.

METHODS/DESIGN

This is a three-arm, prospective, randomized controlled clinical trial to compare: Group 1 - Usual Care, Group 2 - Usual Care Plus LEF-SCP, and Group 3 - Usual Care Plus LEF-SCP Plus Follow-Up. Participants will be HNC survivors aged > 18 years of age, who meet predefined inclusion and exclusion criteria. A sample size of 75 participants is targeted. Interventions will be provided by trained staff. The study assessments for all groups will take place at five points: study entry then 3, 6, 9, and 12 months post enrollment. Outcome measures include: (1) feasibility (barriers to implementation, safety, and satisfaction) of the proposed intervention; (2) self-efficacy and adherence to self-care; and (3) preliminary efficacy (LEF progression, symptom burden, and functional status) of the proposed intervention.

DISCUSSION

This will be the first study to evaluate the feasibility of a LEF-SCP in the HNC population and its impact on self-efficacy and adherence. Furthermore, it will evaluate the potential benefit of routine follow-up on adherence and fidelity to the self-care protocol. We expect that the trial will provide evidence supporting the feasibility of a LEF self-care program. In addition, we anticipate that preliminary data will support improved outcomes including increased adherence and fidelity, and decreased LEF-associated symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov, a service of the US National Institute of Health (NCT03030859). Registered on 22 January 2017.

A Pre-clinical Animal Model of Secondary Head and Neck Lymphedema

Head and neck lymphedema (HNL) is a disfiguring disease affecting over 90% of patients treated for head and neck cancer. Animal models of lymphedema are used to test pharmacologic and microsurgical therapies; however, no animal model for HNL is described in the literature to date. In this study we describe the first reproducible rat model for HNL. Animals were subjected to two surgical protocols: (1) lymphadenectomy plus irradiation; and (2) sham surgery and no irradiation. Head and neck expansion was measured on post-operative days 15, 30 and 60. Magnetic resonance imaging (MRI) was acquired at the same time points. Lymphatic drainage was measured at day 60 via indocyanine green (ICG) lymphography, after which animals were sacrificed for histological analysis. Postsurgical lymphedema was observed 100% of the time. Compared to sham-operated animals, lymphadenectomy animals experienced significantly more head and neck swelling at all timepoints (P < 0.01). Lymphadenectomy animals had significantly slower lymphatic drainage for 6 days post-ICG injection (P < 0.05). Histological analysis of lymphadenectomy animals revealed 83% greater subcutis thickness (P = 0.008), 22% greater collagen deposition (P = 0.001), 110% greater TGFβ1+ cell density (P = 0.04), 1.7-fold increase in TGFβ1 mRNA expression (P = 0.03), and 114% greater T-cell infiltration (P = 0.005) compared to sham-operated animals. In conclusion, animals subjected to complete lymph node dissection and irradiation developed changes consistent with human clinical postsurgical HNL. This was evidenced by significant increase in all head and neck measurements, slower lymphatic drainage, subcutaneous tissue expansion, increased fibrosis, and increased inflammation compared to sham-operated animals.