Update Course Rewind: Cryoanalgesia in Pectus Cases 2024

The Question

Should cryoanalgesia for pectus excavatum repair be performed through a double lumen endotracheal tube with selective lung deflation, or can adequate nerve blocks be achieved with a single lumen tube and mediastinal dissection?

The Case for Double Lumen Intubation

One position holds that double lumen tubes should be used in all cases 4:19. The exposure of the intercostal nerves is described as "exceptional" [q1], and the technique ensures posterior enough probe placement to capture the lateral cutaneous branch [q1]. This matters because cadaver work from UCSF demonstrated that 18% of lateral cutaneous branch nerves lie posterior to the mid-axillary line 5:13, and the freeze point used is 4 centimeters from the vertebral column in the posterior axillary line 1:30.

The double lumen tube addresses two distinct failure modes. First, it minimizes pneumothorax risk by deflating the lung and maximizing working space so the cryoprobe does not contact lung tissue 4:19. Second — and emphasized as the major advantage — it prevents the nerve block from being performed too far anteriorly, which renders the block ineffective 4:39. "I've gotten multiple calls from other surgeons that say, sometimes my blocks don't work and invariably, it's a surgeon using a single lumen tube, doing the block too far anteriorly because they can't get posterior to that anterior axillary line" [q2]. The claim is direct: inadequate posterior access with single lumen tubes leads to missed blocks because "if you don't get posterior enough, that's when you get blocks that are ineffective" [q3].

The anatomic rationale extends beyond the lateral cutaneous branch. The UCSF cadaver study identified a large collateral branch of the intercostal nerve running along the superior aspect of the rib, separate from the main intercostal nerve on the inferior aspect 5:46. In 20 patients treated with a dual freeze point technique targeting both branches, peak pain scores dropped from approximately 5 to approximately 3 6:22, and 98% of patients were discharged the next day 6:26. In the formal UCSF study of 22 patients receiving two freeze points per interspace, length of stay decreased from 2 days to 1 day 6:32, and 9 of 22 patients reported pain scores of zero 6:42. The proponent notes that with the new faster probe, "it's very easy to do. The probe takes half the amount of time, and now I'm doing double the number of blocks" [q4].

The Case for Single Lumen Intubation

The alternative approach uses a single lumen tube with mediastinal dissection, crossing from the right to the left side [disagreement context]. This technique has documented success among some surgeons, though the specific outcomes and patient numbers were not detailed in this discussion. The approach presumably accepts narrower working space in exchange for avoiding double lumen tube placement, which carries its own risks and requires specific anesthetic expertise not universally available.

The single lumen approach may be particularly relevant given that cost and equipment availability are the primary barriers to cryoanalgesia adoption — 40% of surveyed surgeons cited cost as the main reason they do not use the technique 2:33, and 50% have never used it at all 2:26. If double lumen intubation is positioned as mandatory rather than optimal, it adds another layer of resource and training requirements to an already underutilized technique.

The new probe technology may also narrow the gap between approaches. The improved shaft insulation allows the probe to contact lung tissue safely since it only reaches room temperature 3:10, which is "particularly important for people who are not using a double lumen tube where they're crossing the mediastinum and have the lung as an issue," according to one discussant 3:10. This suggests the pneumothorax risk argument may carry less weight with newer equipment.

Where They Agree

Both approaches aim for the same anatomic target: the intercostal nerves from T3 to T8 (or T7 in most literature) 1:39, positioned in the posterior axillary line 1:30. Both recognize that anterior placement produces failed blocks. Both supplement cryoanalgesia with immediate subpleural injection of 0.25% marcaine with epinephrine 2:02, which works immediately rather than waiting 8 to 10 hours for the cryo block to take effect 2:02 and requires only 15 seconds per interspace 2:13. Both agree that cryoanalgesia controls pain and decreases hospital length of stay with few short-term complications 7:00.

What Would Resolve It

A direct comparison was not proposed in this discussion. The audience poll showed 50-50 usage of double versus single lumen tubes, suggesting equipoise in practice. Resolution would require a study comparing block efficacy — measured by pain scores, opioid consumption, and block failure rates — between the two intubation strategies, controlling for surgeon experience and probe placement verification. Until then, the choice appears to rest on local expertise, equipment availability, and whether the surgeon prioritizes maximal anatomic exposure over procedural simplicity.

The Question

When performing intercostal nerve cryoablation during pectus excavatum repair, should surgeons routinely use double lumen endotracheal intubation to deflate the operative lung, or can single lumen intubation with mediastinal dissection provide adequate exposure?

The Case for Double Lumen Intubation

John De Fiori uses double lumen tubes in all cases 4:19. The rationale rests on two advantages: exceptional exposure of the intercostal nerves, and assurance that the cryoprobe is applied posteriorly enough to capture the lateral cutaneous branch [q1]. "The exposure of the intercostal nerves is exceptional, and it ensures that you're applying it posterior enough, so you get the lateral cutaneous branch" [q1].

The anatomic stakes are specific. A cadaver study by Sung Kim at UCSF demonstrated that 18% of lateral cutaneous branch nerves lie posterior to the mid-axillary line 5:13. If the freeze point is placed too anteriorly — anterior to the posterior axillary line landmark of 4 centimeters from the vertebral column 1:30 — the block will fail. "If you don't get posterior enough, that's when you get blocks that are ineffective" [q3].

De Fiori reports receiving multiple calls from surgeons whose blocks sometimes fail, and the pattern is consistent: single lumen tube use correlating with anterior placement. "I've gotten multiple calls from other surgeons that say, sometimes my blocks don't work and invariably, it's a surgeon using a single lumen tube, doing the block too far anteriorly because they can't get posterior to that anterior axillary line" [q2]. The double lumen tube prevents this error by collapsing the lung and opening the posterior chest wall 4:39.

There is also a safety consideration. Pneumothorax can occur if the lung tears after inadvertently adhering to the cryoprobe 4:13. Deflating the lung maximizes working space and reduces the chance of probe-lung contact 4:19. The newer cryoprobe shaft reaches only room temperature rather than freezing temperature 3:10, which mitigates but does not eliminate this risk.

The Case for Single Lumen Intubation

Some surgeons achieve successful nerve blocks using single lumen tubes by performing mediastinal dissection and working across from the right to the left side 4:39. The audience poll at the update course split evenly — half use double lumen, half use single lumen — suggesting that single lumen approaches are working for a substantial portion of practitioners.

The single lumen approach avoids the added complexity and potential complications of double lumen intubation. Double lumen tubes require more skill to place, carry a risk of malposition, and are not universally available in all practice settings. For surgeons who have developed reliable technique with single lumen tubes, the mediastinal dissection provides sufficient visualization to place the cryoprobe posteriorly.

The newer probe design may also reduce the practical difference between approaches. The shaft now reaches only room temperature 3:10, making inadvertent lung contact less consequential. The stiffer shaft improves ease of placement [excerpts], which could help surgeons using single lumen tubes achieve posterior positioning more reliably.

Where They Agree

Both approaches share the same anatomic target: the intercostal nerve at the posterior axillary line, 4 centimeters from the vertebral column 1:30, with cryoablation performed from T3 to T8 1:39. Both recognize that anterior placement causes block failure. Both acknowledge that the lateral cutaneous branch must be captured for effective analgesia.

The goal is identical: effective pain control that allows next-day discharge. De Fiori reports that 98% of his patients go home the next day 6:26. The question is not whether cryoanalgesia works — the discussants agree that it controls pain and decreases hospital length of stay with few short-term complications 7:00 — but which intubation strategy optimizes the technical execution.

What Would Resolve It

The discussants did not specify what evidence would settle the question. A comparative study measuring block failure rates, pain scores, and complication rates between double lumen and single lumen approaches would provide direct evidence. Such a study would need to control for surgeon experience, since the single lumen technique may require a learning curve that experienced users have already overcome.

Until then, the choice appears to rest on individual surgeon comfort, institutional resources, and anesthesia team capability with double lumen intubation. The 50-50 split in the audience suggests that both approaches can succeed in practiced hands [excerpts].