Impact of anesthesia for cancer surgery: Continuing Professional Development

Purpose

A number of original publications and review articles have addressed the issue of perioperative immune modulation and cancer outcome. The objective of this module is to review current understanding surrounding the pathways involved and the evidence implicating commonly used anesthetic agents.

Principal findings

Drugs commonly used in anesthetic practice have been shown to affect various components of the immune system in laboratory animal and human in vitro models. It has been hypothesized that these effects may favour tumour recurrence and metastasis formation. Inhalational agents and opiates have potential negative immunomodulatory effects; on the other hand, regional anesthesia and propofol may have positive effects on immune function modulation. However, the clinical relevance of these studies to human cancer outcome is unknown since clinical trials are equivocal, and results of in vitro and animal model studies cannot be extrapolated to clinical practice. Furthermore, there is a lack of rigorous clinical trials demonstrating clinical outcome benefit for one technique over another. It remains unclear how anesthetic drugs influence the immune system in relation to tumour cell elimination and clinical cancer outcome.

Conclusions

Recommendations for a specific anesthetic technique based on cancer outcome alone cannot be made. A pragmatic solution would be to offer regional anesthesia in isolation or combined with propofol infusion to cancer patients if appropriate and if local expertise is available. Regional anesthesia offers excellent analgesia, a low incidence of postoperative nausea and vomiting, and a favourable immunological profile based on current understanding of laboratory evidence.     

Improved outcomes after technical modifications in tubularized incised plate urethroplasty for mid-shaft and proximal hypospadias

Purpose

To investigate and compare the outcomes after tubularized incised plate (TIP) urethroplasty in mid-shaft and proximal hypospadias using a standard and a modified technique.

Methods

We conducted a retrospective study in 104 consecutive children who underwent mid-shaft or proximal TIP repairs from Jan 2007 to Sept 2015. Patients in Cohort One had dorsal dartos (DD) neourethral coverage while patients in Cohort Two had either de-epithelialized split preputial (DESP) or tunica vaginalis (TV) flap coverage. TV flap was used only when DESP flap was not sufficient to cover the neourethra.

Results

There were 52 patients each in Cohort One (DD, n = 52) and Cohort Two (DESP, n = 38; TV, n = 14) with no difference in ratio of mid-shaft/proximal between the two cohorts. At a median follow-up of 28 months, 36 patients (34.6 %) developed 47 complications including fistula (n = 19; 18.3 %) and neourethral dehiscence (n = 4; 3.8 %). Cohort One patients had significantly more fistula (28.8 vs 7.7 %; p = 0.005) and neourethral dehiscence (7.7 vs 0 %; p = 0.04) than Cohort Two. There was no difference between the two cohorts in the complication rates of meatal stenosis, recurrent ventral curvature and neourethral stricture.

Conclusions

Both DESP and TV flap appear to be superior to DD in preventing fistula and neourethral dehiscence in non-distal TIP repairs.

     

Feasibility study of using high-frequency ultrasonic Nakagami imaging for characterizing the cataract lens in vitro

A cataract is a clouding of the crystalline lens that reduces the amount of incoming light and impairs visual perception. Phacoemulsification is the most common surgical method for treating advanced cataracts, and determining the optimal phacoemulsification energy is dependent on measuring the hardness of the lens. This study explored the feasibility of using an ultrasonic parametric image based on the Nakagami distribution to quantify the lens hardness. Young's modulus was measured in porcine lenses in which cataracts had been artificially induced. High-frequency ultrasound at 35 MHz was used to obtain the B-mode and Nakagami images of the cataract lenses. The averaged integrated backscatter and Nakagami parameters were also estimated in the region of interest. The experimental results show that the conventional B-scan and integrated backscatter are inadequate for quantifying the lens hardness, whereas Nakagami imaging allows different degrees of lens hardening to be distinguished both globally and locally based on the concentration of fiber coemption therein.