Hypoglossal Nerve Stimulation Jolie Chang, MD Assistant Professor - - PDF document

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Sep 18, 2023 277 likes •437 views

2/11/18 Hypoglossal Nerve Stimulation Jolie Chang, MD Assistant Professor Department of Otolaryngology, Head and Neck Surgery Disclosure None 1 2/11/18 Outline HNS Development WHO: Current clinical criteria for HGNS HOW:

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Hypoglossal Nerve Stimulation

Jolie Chang, MD Assistant Professor Department of Otolaryngology, Head and Neck Surgery

Disclosure

§ None

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Outline

§ HNS Development § WHO: Current clinical criteria for HGNS § HOW: Surgical procedure and technique § WHY: Effectiveness of therapy § Future directions

OSA

§ 60-90% patients have multi- level collapse § DISE used to identify major sites of collapse

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Upper Airway Muscles in Sleep

§ Increased Collapsibility

Anatomy
Neuromuscular Control

§ Genioglossus = UA dilator

Improves upper airway

patency

GGEMG declines in sleep

– worse in OSA

Activation improves airflow

and OSA

Genioglossus stimulation

§ Animal

Electrical stimulation of GG restores airway patency in sleep

§ Human

GG stimulation associated with

‒ Increased maximum inspiratory airflow, without arousals ‒ Enlargement of retrolingual and retropalatal airway

Distal and proximal hypoglossal nerve stimulation can open

airway and improve airflow Schwartz Ar, et al. J. Appl Physiol. 1996.

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Pcrit

§ Genioglossus contraction improves upper airway patency Oliven A, et al. J Appl Physiology. Feb 2003.

Stimulation systems

§ Feasibility trials Schwartz et al. J Appl Physiol 2013.

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Hypoglossal Nerve Stimulation

§ FDA approved first device – Inspire II 4/2014 § Fully implanted system with sleep remote § Unilateral (right) Hypoglossal Nerve stimulation § Synchronized to inspiration

Clinical Evidence

§ STAR Trial: Strollo et al. NEJM 2014. § 126 patients with mod-severe OSA § 12-months post implant § Reduced:

AHI (29.3 to 9) 68%
ODI (25.4 to 7.4)
ESS survey
FOSQ survey
Daily use: 86%

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3-year Data

29.3 9.0 9.7 6.2 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 Baseline N=126 12 Month N=124 18 Month N=121 36 Month N=98 Median AHI

AHI

Gillespie et al. Otolaryngology-HNS. 2017.

Compliance and ESS

Gillespie et al. Otolaryngology-HNS. 2017.

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Clinical Indications for HGNS

§ Patient goals and expectations § CPAP intolerance § BMI < 35 § PSG: AHI 15 to 65

<25% Central apnea

§ Appropriate airway anatomy: DISE

Rule out complete concentric collapse at the palate

§ Considerations:

MRI needs
Medical history
Surgical history: Prior implants, prior breast surgery

Preoperative evaluation DISE

§ Rule out complete concentric collapse at soft palate § Vanderveken et al. J Clin Sleep Med 2013:

21 pts – predictive value of DISE for HGNS outcomes
16 pts without palate CCC: AHI 38 to 12
5 pts with CCC: no change in postop AHI

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Intraoperative – Hypoglossal Nerve

§ NIMS electrodes § Goal: unhindered tongue PROTRUSION and STIFFENING § Include nerve branches for:

Protrusion = oblique and horizontal genioglossi (GG)
Stiffen = intrinsic transverse/vertical (TV)
C1 = geniohyoid (if possible)

§ Exclude

Retrusion = hyoglossus, styloglossus (HG, SG)

NIMS

§ 18mm paired electrodes § Genioglossus: Floor of mouth § Hyoglossus: lateral tongue

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Hypoglossal Nerve

§ Proximal lateral branches innervate retrusors

Hyoglossus
Styloglossus

§ Distal, medial branches innervate protrusors

Genioglossus
Intrinsic T/V

§ C1 to geniohyoid

Dedhia et al. Neuroanatomy of the tongue.

S"mula"on Site Styloglossus (SG) Hyoglossus (HG) Genioglossus (GG) Geniohyoid (GH)

Retractor Muscles Protrusor Muscles

Hypoglossal Nerve

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Electrode placement

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System Validation Postoperative Care

§ Reduced postoperative pain and medication use § Reduced postoperative hospital stay § CXR § Precautions: no excessive right arm motion, no heavy lifting x 2 weeks § Dressings off POD #2

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Activation and Acclimation

§ 1 month postop § Thresholds

Sensation
Discomfort

§ Activation Range provided § Patient self titrates over 1 month § Therapy works by balancing functional threshold with arousal threshold and comfort

PSG at 2 months

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DISE Awake Laryngoscopy with Stimulation

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New Devices – Selective Nerve Stimulation

§ ImThera Medical (Aura6000)- Trial § Current Phase III trial § No DISE requirement § 6 electrodes, circum

OSA Surgery Treatment Paradigm

§ Address anatomic causes of obstruction

Palatine and Lingual Tonsils
Soft palate: UPPP
Parapharyngeal fat, macroglossia: Weight
Epiglottis: epiglottectomy, hyoid suspension, HGNS?
Retrognathia: MMA

§ HGNS to improve neuromuscular tone in sleep § Patients choice and shared decision making

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HGNS Advantages

§ Addresses reduced neuromuscular tone in OSA § Can be titrated to effect and reprogrammed § Excellent safety profile, low morbidity § Reduced post-operatve pain, faster recovery § Provides multi-level therapy § Good patient adherence over time § Good results in properly selected patients

Future of HGNS

§ Transcutaneous continuous stimulation § New devices, stimulation schemes § Questions

Who is the ideal candidate?
What are the long term effects of chronic stim?
Examine the nonresponders

§ Personalized medicine: How fit into OSA surgery?

Address anatomic causes: tonsils, weight, craniofacial
HGNS for neuromuscular stim
Shared patient decision making