The negative chronotropic effect during lumbar spine surgery: A systemic review and aggregation of an emerging model of spinal cardiac reflex

Dural manipulation coinciding with transient asystole during lumbar spine surgery: illustrative case

BACKGROUND

Hemodynamic disturbances during lumbar spine surgeries have proven to be exceptionally rare, with only seven published cases demonstrating instances where intraoperative dural manipulation coincided with bradycardia, hypotension, and/or asystole.

OBSERVATIONS

The authors present the case of a 39-year-old male with a history of chronic low-back pain and leg weakness. Imaging demonstrated a disc herniation at L5-S1, resulting in impingement of the left S1 traversing nerve root. The patient agreed to surgery. The preoperative workup was unremarkable. While retracting the S1 nerve root, transient asystole occurred when the S1 nerve root was manipulated, causing the patient's heart rate to drop from 51 to 0 bpm. Manipulating the nerve root once again triggered a similar event, and upon cessation of the surgical stimulus, the patient's heart rate spontaneously returned to baseline. Other potential causes of these hemodynamic perturbations were excluded.

LESSONS

As in other reported cases, each cardiovascular disturbance corresponded with either direct or indirect dural manipulation. Given the limited number of lumbar spinal cases reported to have undergone hemodynamic perturbances via dural manipulation, this case report provides evidence for the likelihood of a spinal-cardiac reflex between the cardiovascular system and the spinal dura mater. https://thejns.org/doi/10.3171/CASE24158.

Unexpected Bradycardia Related to Surgical Manipulation During Thoracolumbar Spinal Surgery

BACKGROUND

Although spinal surgery can offer pain relief and functional improvements in daily life, it is often associated with various perioperative complications. The incidence of cardiac complications associated with spinal surgery is relatively low. We evaluated frequency and causes for bradycardia incidents in posterior thorocolumbar spinal surgeries.

METHODS

We retrospectively evaluated posterior thoracolumbar spinal surgeries between 2018-2022 for bradycardic events in our tertiary general hospital. Patients operated for degenerative changes or disk herniations are included, other cases for tumors, trauma, arteriovenous (AV) fistulae or previously operated are excluded.

RESULTS

The study reached 6 eligible patients (4 female and 2 male) aged between 45-75 years (mean: 63.3) among 550 patients operated between 2018-2022. The rate of bradycardia was 1.09%. Of these, 5 patients (lumbar discectomy: one; posterior stabilization:4) exhibited it following L2 and L3 root manipulation and one presented it following L4-5 discectomy. In each of these cases, bradycardia occurred during surgical manipulation and ceased upon removal of the insult. None of the cases exhibited accompanying hypotension. The patient's heart rates were seen to drop to lowest the of 30 beats/min, and all patients exhibited favorable outcomes and no postoperative cardiac complications over a mean follow-up period of 20 months (range: 10-40 months).

CONCLUSIONS

The current study examines the occurrence of unexpected bradycardia events associated with thoracolumbar spinal surgery during surgical handling of the dura mater. Awareness of such incidents among surgeons and anesthesiologists can help prevent catastrophic outcomes caused by adverse cardiac events.

Negative Chronotropic Cardiovascular Changes in Lumbar Spine Surgery: A Potential Spinal-Cardiac Reflex?

Cardiovascular changes following lumbar spine surgery in a prone position are exceedingly rare. Over the past 20 years, a total of six cases have been published where patients experienced varying degrees of bradycardia, hypotension, and asystole, which could be attributed to intraoperative dural manipulation. As such, there is emerging evidence for a potential neural-mediated spinal-cardiac reflex. The authors report their experience of negative chronotropy during an elective lumbar spine surgery that coincided with dural manipulation and review the available literature. A 34-year-old male presented with a long-standing history of lower back pain recently deteriorating to bilaterally radiating leg pain, with restricted left leg raise, and numbness at the left L5 dermatomal territory. The patient was an athletic police officer with no comorbidities or past medical history. Magnetic resonance imaging lumbosacral spine revealed spinal stenosis most pronounced at L4/L5 and disc bulges at L3/L4 and L5/S1. The patient opted for lumbar decompression surgery. After an unremarkable comprehensive preoperative workup, including cardiac evaluation (electrocardiogram, echocardiogram), the patient was induced general anesthesia in a prone position. A lumbar incision was made from L2 to S1. When the left L4 nerve root was retracted while removing the prolapsed disc at L4/L5, the anesthetist cautioned the surgeon of bradycardia (34 beats per minute [bpm]), and the surgery was immediately stopped. The heart rate improved to 60 bpm within 30 seconds. When the root was later retracted again, a second episode of bradycardia occurred for 4 minutes with heart rate declining to 48 bpm. The surgery was stopped, and after 4 minutes, the anesthetist administered 600 µg of atropine. The heart rate then rose to 73 bpm within 1 minute. Other potential causes for bradycardia were excluded. The total blood loss was estimated to be 100 mL. He remains well at his 6-month follow-up and has returned to work as normal. Akin to previously published cases, each episode of bradycardia coincided with dural manipulation, which may indicate a possible reflex between the spinal dura mater and the cardiovascular system. Such a rare adverse event may occur even in seemingly healthy, young individuals, and anesthetists should caution the operating surgeon of bradycardias to exclude operative manipulation of the dura as the cause. While this phenomenon is only reported in a handful of lumbar spine surgery cases, it provides evidence for a potential spinal-cardiac physiological reflex in the lumbar spine that may be neural mediated and should be investigated further.

Acute recurrent bradycardia with evoked potential loss during transforaminal lumbar interbody fusion

During a transforaminal lumbar interbody fusion a patient experienced acute intermittent bradycardia with manipulation of the intervertebral body space, followed by loss of somatosensory evoked potentials that did not recover. Postoperative evaluation revealed new bilateral lower extremity sensory and motor deficits. We postulate an afferent reflex arc to explain this and other reported instances of bradycardia and asystole during transforaminal lumbar interbody fusion surgery. Awareness of the association between bradycardia during lumbar spine surgery may alert anaesthetists, surgeons and neuromonitoring teams to impending neurological harm.

Cardiovascular Changes and Lumbar Spine Surgery: A Neglected Entity

Cardiovascular changes following lumbar spine surgeries in the prone position have been less commonly described. Here, we report a case of an elderly male patient undergoing lumbar spine decompression and transforaminal interbody fusion who developed multiple but transient episodes of hypotension and bradycardia. Anesthesiologist should be vigilant while monitoring such patients and should use invasive blood pressure monitoring if possible, so as to detect transient cardiovascular episodes which may progress and results in a dreadful outcome.

Photic sneeze reflex: another variant of the trigeminocardiac reflex?

The photic sneeze reflex (PSR) is a condition of uncontrollable sneezing episodes in response to bright light. This reflex often manifests as a mild phenomenon but may cause devastating consequences in some situations (aeroplane pilots, car drivers, etc.). Its exact mechanism is poorly understood. Interestingly, the roles of the fifth and tenth cranial nerves, brainstem nuclei and inciting patterns closely mimic a well-known brainstem reflex, known as the trigeminocardiac reflex (TCR). In this critical review, we hypothesize that the PSR can be a variant of the TCR. This concept will lead to a better understanding of the PSR and sharpens the TCR characteristics and open the doors for new research possibilities.

The clinical surrogate definition of the trigeminocardiac reflex: Development of an optimized model according to a PRISMA-compliant systematic review

BACKGROUND

The trigeminocardiac reflex (TCR) is defined as sudden onset of parasympathetic dysrhythmias including hemodynamic irregularities, apnea, and gastric hypermotility during stimulation of sensory branches of the trigeminal nerve. Since the first description of the TCR 1999, there is an ongoing discussion about a more flexible than the existing clinical definition. Aim of this work was to create a clinical surrogate definition through a systematic review of the literature.

METHODS

In this meta-analysis study, literature about TCR occurrences was, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement, systematically identified through various search engines including PubMed (Medline), Embase (Ovid SP), and ISI Web of Sciences databases from January 2005 to August 2015. TCR was defined as a drop of heart rate (HR) below 60 bpm or 20% to the baseline. We extracted detailed data about hemodynamic changes and searched for connections between arterial blood pressure (BP) and HR changes during such episodes.

RESULTS

Overall 45 studies harboring 57 patients were included in the study but only 32 patients showed sufficient data for final analyze. HR showed a nonlinear behavior with a "tipping point" phenomena that differs in variance from the central/peripheral (20-30% drop) to ganglion (40-49% drop). BP showed a linear behavior with a "central limit" phenomena not differing in variance in the whole subgroup (30-39% drop). An analyzation of the correlation between BP and HR showed a trend to a linear correlation.

CONCLUSIONS

We can show for the first time that HR is the dominant variable in the TCR and present a new surrogate definition model. This model and the role of BP must be better investigated in further studies.

Definition and Diagnosis of the Trigeminocardiac Reflex: A Grounded Theory Approach for an Update

Background

The trigeminocardiac reflex (TCR) is defined as sudden onset of parasympathetic dysrhythmias including hemodynamic irregularities, apnea, and gastric hypermotility during stimulation of sensory branches of the trigeminal nerve. Since the first description of the TCR in 1999, there is an ongoing discussion about a more emergent clinical definition. In this work, the author worked out an approach to such an improved definition.

Methods

In this study, a grounded theory approach was used. Literature about TCR was systematically identified through PubMed (MEDLINE), EMBASE (Ovid SP), and ISI Web of Sciences databases from 1/2005 until 8/2015. TCR was defined as a drop of heart rate (HR) below 60 bpm or 20% to the baseline. A grounded theory approach was used to analyze and interpret the data through a synthesis by the researcher’s perspectives, values, and positions.

Results

Out of the included studies, the authors formed available data to an update of the understanding of changes in hemodynamic parameters (HR and blood pressure) in a TCR. According to this update, an HR deceleration should be a constant observation to identify a TCR episode while a drop in blood pressure should probably not being fixed to a certain percentage of decrease.

Conclusion

The here presented working definition improves our understanding of the TCR. It leads the way to a new understanding of the TCR for a proper clinical definition.

Posterior meningeal artery DMSO injection resulting in reproducible asystole prior to Onyx therapy of a dural arteriovenous fistula: a previously undescribed variant of the trigeminocardiac reflex or a new phenomenon?

We describe a case of reproducible asystole during endovascular treatment of a posterior fossa dural arteriovenous fistula. Catheterisation of the posterior meningeal artery, a branch of the vertebral artery in this patient, followed by dimethyl sulfoxide injection prior to Onyx administration resulted in two episodes of asystole.To the best of our knowledge, this is the first reported case of asystole occurring during endovascular intervention in the posterior meningeal artery. This may represent a previously undescribed variant of the trigemino-cardiac reflex (TGCR) caused by chemical stimulation of small areas of trigeminally innervated posterior fossa dura. Alternatively, this may represent a newly identified phenomenon with chemical stimulation of regions of posterior fossa dura innervated by branches of the vagus nerve leading to increased parasympathetic activity and resultant asystole.In either case, it is important to recognise the potential for such episodes in this vascular territory to allow case planning and management.