Lactate Concentrations in Incisions Indicate Ischemic-like Conditions May Contribute to Postoperative Pain

The substances in wounds that cause incisional pain and hyperalgesia after surgery are poorly understood. We have developed and characterized rat models for incision-induced pain behaviors and measured increased tissue hydrogen ion concentration. Because lactate may facilitate nociceptor responses to low pH and contribute to ischemic pain mechanisms, we measured tissue lactate after incision of the plantar region of the hindpaw, gastrocnemius muscle, and paraspinal region in halothane anesthetized rats using in vivo microdialysis. Incisions were performed at 1 site (plantar, gastrocnemius, or paraspinal incision) in each rat. The corresponding contralateral side was used as the control. In anesthetized rats, a microdialysis fiber was passed into the incision and the control side. L-Lactate was measured using the lactate oxidase method. Tissue concentration was determined from postoperative day 0 to postoperative day 14 using the no net flux method. Lactate was increased on the day of hindpaw incision to 3.6 +/- 1.6 mmol/L compared with control (2.1 +/- .6 mmol/L) and remained increased through 7 days. In the gastrocnemius muscle, lactate was increased the day after incision (4.2 +/- 1.2 mmol/L vs 1.7 +/- .5 mmol/L) until postoperative day 7. On the day of the paraspinal incision, lactate was 3.4 +/- 1.1 mmol/L on the operated side and 2.2 +/- .6 mmol/L in the control side. Lactate remained increased through postoperative day 8 at the paraspinal incision. These experiments demonstrate that incision of the plantar hindpaw, the gastrocnemius muscle, and the paraspinal region increased tissue lactate concentration. The wound environment contains increased lactate at the same time that pH is decreased; lactate could potentially facilitate nociceptor activation by low pH and contribute to pain after surgery.

PERSPECTIVE

This study demonstrates that lactate is increased in wounds when pain behaviors and acid are increased. Lactate and low pH are present in incisions and indicate an ischemic pain mechanism that may contribute to postsurgical pain.

[Comparison of phantom limb pain or phantom extremity sensation of upper and lower extremity amputations]

The aim of this retrospective study is to evaluate the upper and the lower extremity amputations with regard to phantom pain, phantom sensation and stump pain. A questionnaire consisting of 23 questions was send to the patients who underwent upper or lower extremity amputation surgery between 1996- 2005. The patients were questioned for the presence of phantom pain and sensations and if they existed for the frequency, intensity, cause of amputation, pre-amputation pain, stump pain, usage of artificial limb. Totally 147 patients were included and the response rate was 70 %. The incidence of phantom pain in Upper Extremity Group was 60 % and 65.8% in Lower Extremity Group. The incidence of phantom sensations was 70.7% in Upper Extremity Group and 75.6% in Lower Extremity Group. There was no significant difference between two groups considering in phantom pain and phantom sensations. The phantom pain was significantly higher in patients who lost dominant hand, experienced pre amputation pain and suffered stump pain. There were no significant differences in regard to phantom pain and sensation between upper and lower extremity amputations. However the presence of preamputation pain, stump pain and amputation of dominant hand were found as risk factors for the development of phantom pain.

The effect of 3-in-1 femoral nerve block with ropivacaine 0.375% on postoperative morphine consumption in elderly patients after total knee replacement surgery

Total knee replacement (TKR) is one of the most painful orthopedic surgical procedures. This study was aimed to investigate the effect of a single-shot preoperative 3-in-1 femoral nerve block on postoperative pain by using 0.375% ropivacaine, and on the consumption of morphine by using PCA following the TKR surgery. Side effects were also evaluated in this setting. 34 patients were included in this study. Group R (n=17) received a 3-in-1 femoral nerve block (FNB) with 40 mll of ropivacaine 0.375%. Group S (n=17) received only a 2 mg loading dose of morphine 30 minutes before the end of surgery, and no block was performed. Both groups received general anesthesia and postoperatively had a PCA pump programmed to deliver morphine. VAS scores at rest, morphine consumption and adverse effects were recorded. Two patients were excluded from each group. Pain scores at 0, 1, 2, 3, 4, 6, 8 postoperative hours were significantly lower in group R in resting position (p<0.05). Group R experienced no pain at the recovery room and this state lasted 8 hours after the surgery while group S reached the acceptable score (VAS ? 3) one hour after leaving the recovery room. The morphine requirement was significantly lower in Group R at 12, 18, 24, 48 hr after TKR (p<0.001). Side effects were also lower in this group. Preoperative single-shot 3-in-1 FNB with 40 cc of ropivacaine 0.375% provides better VAS scores, less morphine consumption and fewer side effects in elderly patients when compared to the group with no block.

Low-dose intravenous ketamine potentiates epidural analgesia after thoracotomy

BACKGROUND

Ketamine potentiates intravenous or epidural morphine analgesia. The authors hypothesized that very-low-dose ketamine infusion reduces acute and long-term postthoracotomy pain.

METHODS

Forty-nine patients scheduled to undergo open thoracotomy were randomly assigned to receive one of two anesthesia regimens: continuous epidural infusion of ropivacaine and morphine, along with intravenous infusion of ketamine (0.05 mg . kg(-1) . h(-1) [approximately 3 mg/h], ketamine group, n = 24) or placebo (saline, control group, n = 25). Epidural analgesia was continued for 2 days after surgery, and infusion of ketamine or placebo was continued for 3 days. Pain was assessed at 6, 12, 24, and 48 h after surgery. Patients were asked about their pain, abnormal sensation on the wound, and inconvenience in daily life at 7 days and 1, 3, and 6 months after surgery.

RESULTS

The visual analog scale scores for pain at rest and on coughing 24 and 48 h after thoracotomy were lower in the ketamine group than in the control group (pain at rest, 9 +/- 11 vs. 25 +/- 20 and 9 +/- 11 vs. 18 +/- 13; pain on coughing, 26 +/- 16 vs. 50 +/- 17 and 30 +/- 18 vs. 43 +/- 18, mean +/- SD; P = 0.002 and P = 0.01, P < 0.0001 and P = 0.02, respectively). The numerical rating scale scores for baseline pain 1 and 3 months after thoracotomy were significantly lower in the ketamine group (0.5 [0-4] vs. 2 [0-5] and 0 [0-5] vs. 1.5 [0-6], median [range], respectively; P = 0.02). Three months after surgery, a higher number of control patients were taking pain medication (2 vs. 9; P = 0.03).

CONCLUSIONS

Very-low-dose ketamine (0.05 mg . kg(-1) . h(-1)) potentiated morphine-ropivacaine analgesia and reduced postthoracotomy pain.

A case of axillary web syndrome with subcutaneous nodules following axillary surgery

Axillary web syndrome (AWS) is a cause of morbidity in the early postoperative period following axillary surgery, which is characterized by cords of subcutaneous tissue extending from the axilla into the medial arm. Few reports have been published describing this entity, which results in pain and a limitation of shoulder abduction. Here, we report a case of AWS that was accompanied with sub-cutaneous nodules mimicking recurrence of breast cancer.

Environmental and genetic factors associated with morphine response in the postoperative period

OBJECTIVE

The aim of this study was to investigate the respective influence of genetic and nongenetic factors on morphine dose requirements and adverse effects after colorectal surgery.

METHODS

Seventy-four patients who planned to undergo colorectal surgery were included in this pilot study. The cumulative 24-hour postoperative dose of morphine and postoperative nausea or vomiting requiring the antiemetic ondansetron were the 2 clinical end points. The association of patient characteristics, A118G mu-opioid receptor (OPRM1) single-nucleotide polymorphism (SNP); T802C uridine diphosphate-glucuronosyltransferase 2B7 (UGT2B7) SNP; and 2 adenosine triphosphate-binding cassette, subfamily B, member 1 (ABCB1) (multidrug resistance 1 [MDR1]) exonic SNPs (G2677T/A and C3435T) with study end points was investigated.

RESULTS

Age, creatinine clearance, and the regular use of psychotropic agents were found to be significantly associated with postoperative morphine dose requirements by univariate analysis. Multivariate analysis identified that age (P = .01) and the use of psychotropic agents before surgery (P = .03) were positively associated with a higher rate of morphine consumption. A higher weight (P = .05) and the ABCB1 homozygous GG-CC diplotype (P = .03) were significantly associated with fewer morphine side effects by univariate analysis. The homozygous ABCB1 diplotype (GG-CC) conferred an odds ratio of 0.12 (95% confidence interval, 0.01-0.98) with regard to the use of ondansetron for postoperative nausea or vomiting. Multivariate analysis identified that the ABCB1 GG-CC diplotype was the only borderline-significant (P = .07) predictive factor of morphine side effects.

CONCLUSION

Age and prior use of psychotropic agents are associated with postoperative morphine dose requirements. Whether ABCB1 polymorphisms might predict morphine side effects remains to be determined.

Variability in pain expression characteristics in former preterm infants

OBJECTIVES

To document pain expression characteristics in former preterm infants in the first year of life in whom systematic evaluation and treatment of pain was provided.

METHODS

Data on the Modified Behavioral Pain Scale (MBPS), Visual Analogue Scale (VAS, crying time and heart rate were collected during immunization. The effect of clinical characteristics {postconception and gestational age [PCA], surgery, ventilation, fentanyl, length of stay (LOS)} on bio-behavioral parameters was evaluated.

RESULTS

121 procedures were recorded in 49 infants. GA was 28 (25-32) weeks. PCA was 60 (34-90) weeks. Median MBPS was 8 (2-10), median crying time 44 (0-112) s. Median pre-procedural heart rate was 144 (103-201) and increased to 184 (147-220) afterwards, resulting in a relative increase of 29 (5-99)%. Median VAS score was 7 (1-10). Significant correlations of PCA with pre-procedural heart rate (r=-0.36) and with relative increase in heart rate (r=0.33) were identified. A correlation of LOS on crying time (r=0.37) was observed.

CONCLUSIONS

Correlations of PCA with pre-procedural and relative increase in heart rate reflect the maturational decrease in heart rate. LOS had an effect on pain expression, potentially reflecting the impact of cumulative 'minor' procedural pain.

Failure to resurface the patella during total knee arthroplasty may result in more knee pain and secondary surgery

Resurfacing the patella during primary total knee arthroplasty is controversial. The objective of this meta-analysis was to evaluate the outcome of total knee arthroplasty with or without resurfacing of the patella with particular attention to patient satisfaction, incidence of anterior knee pain, patellar complications, and the need for secondary operations. Computerized databases were searched for citations and published randomized clinical trials relevant to patellar resurfacing from 1966-2003. Of 158 citations identified as related to patellar resurfacing during total knee arthroplasty, 14 articles met all inclusion criteria for this study. The incidence of anterior knee pain was greater in knees with nonresurfaced patellas. Secondary resurfacings for anterior knee pain was needed in 8.7% of nonresurfaced knees. No difference in reported complications existed. Total knee arthroplasty resulted in improvement of functional outcome regardless of whether the patella was resurfaced. Based on the results of this meta-analysis, nonresurfacing of the patella during primary total knee arthroplasty is likely to result in a greater incidence of anterior knee pain, the need for secondary resurfacing in almost one in 10 patients, and possibly less patient satisfaction.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Assessing the role of metabotropic glutamate receptor 5 in multiple nociceptive modalities

Preclinical data, performed in a limited number of pain models, suggest that functional blockade of metabotropic glutamate (mGlu) receptors may be beneficial for pain management. In the present study, effects of 2-methyl-6-(phenylethynyl)-pyridine (MPEP), a potent, selective mGlu5 receptor antagonist, were examined in a wide variety of rodent nociceptive and hypersensitivity models in order to fully characterize the potential analgesic profile of mGlu5 receptor blockade. Effects of 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP), as potent and selective as MPEP at mGlu5/mGlu1 receptors but more selective than MPEP at N-methyl-aspartate (NMDA) receptors, were also evaluated in selected nociceptive and side effect models. MPEP (3-30 mg/kg, i.p.) produced a dose-dependent reversal of thermal and mechanical hyperalgesia following complete Freund's adjuvant (CFA)-induced inflammatory hypersensitivity. Additionally, MPEP (3-30 mg/kg, i.p.) decreased thermal hyperalgesia observed in carrageenan-induced inflammatory hypersensitivity without affecting paw edema, abolished acetic acid-induced writhing activity in mice, and was shown to reduce mechanical allodynia and thermal hyperalgesia observed in a model of post-operative hypersensitivity and formalin-induced spontaneous pain. Furthermore, at 30 mg/kg, i.p., MPEP significantly attenuated mechanical allodynia observed in three neuropathic pain models, i.e. spinal nerve ligation, sciatic nerve constriction and vincristine-induced neuropathic pain. MTEP (3-30 mg/kg, i.p.) also potently reduced CFA-induced thermal hyperalgesia. However, at 100 mg/kg, i.p., MPEP and MTEP produced central nerve system (CNS) side effects as measured by rotarod performance and exploratory locomotor activity. These results suggest a role for mGlu5 receptors in multiple nociceptive modalities, though CNS side effects may be a limiting factor in developing mGlu5 receptor analgesic compounds.

Failure of reconstitution of open-section, posterior iliac-wing bone graft donor sites after lumbar spinal fusion. Observations with implications for the etiology of donor site pain

The objective of this cohort study--conducted at a regional trauma unit in southern Ontario, Canada--was to review the imaging history of open-section, iliac-wing bone graft donor sites in lumbar fusion patients. Intervention entailed review of available X-ray and CT scan images for all patients undergoing lumbar fusion with iliac autograft in the senior author's practice over a 4-year period. Outcome was radiographic confirmation of the absence of bony reconstitution at the iliac harvest site. Of 239 primary fusions performed, 209 complete imaging records were available for review. The images of a further 20 patients who had surgery with the senior author prior to the study period and who presented at the office in the first half of 2000 were also assessed. All cases showed persistence of the iliac donor harvest site defect. Only minimal marginal sclerosis to suggest attempted remodeling was observed. We conclude that iliac-wing bone graft donor sites do not remodel. Given that iliac harvesting is known to increase strain in the pelvis, and that lumbosacral stabilization increases stress in the pelvis, permanent deficiency of iliac bone stock at donor harvest site may be a factor in both primary donor site pain and the observed high frequency of this problem in lumbosacral fusion patients.

How painful are amniocentesis and chorionic villus sampling?

OBJECTIVES

To compare the levels of pain and anxiety associated with amniocentesis (AC), transabdominal chorionic villus sampling (TA-CVS), and transcervical chorionic villus sampling (TC-CVS).

METHODS

We prospectively administered a questionnaire about pain and anxiety to 124 women undergoing AC, 40 undergoing TA-CVS, and 24 undergoing TC-CVS for singleton pregnancies. The level of pain was quantified with numerical and pictorial scales and the degree of anxiety was quantified with a numerical scale (0-100 in increments of 10).

RESULTS

The mean pain score for TA-CVS, 41.4 +/- 18.1, was significantly higher than that for TC-CVS, 26.4 +/- 25.3, p = 0.008. The mean pain score for AC, 35.1 +/- 27.6, was intermediate. A higher degree of anxiety was associated with younger maternal age and nulliparity. A higher degree of anxiety was associated with a higher level of pain.

CONCLUSION

In general, each procedure is associated with a tolerable amount of pain. TA-CVS appears to be the most painful procedure while TC-CVS appears to be the least painful procedure. In certain groups of patients, the procedures may be associated with higher levels of pain and/or anxiety.

Small-incision manual extracapsular cataract extraction using deep-topical, nerve-block anesthesia

BACKGROUND AND OBJECTIVE

To determine whether deep-topical anesthesia is suitable for small-incision manual extracapsular cataract extraction (ECCE).

PATIENTS AND METHODS

Three hundred twenty-six eyes of 253 patients had small-incision manual ECCE under topical anesthesia with a 4% lidocaine-soaked sponge. The severity of the pain, eye movements, blepharospasm, and intraoperative complications were recorded. Patient and surgeon satisfaction levels were assessed.

RESULTS

Operations on 323 eyes (99%) were completed with topical anesthesia. Intraoperatively, topical anesthesia was converted to peribulbar anesthesia in 3 eyes (0.9%) because of excessive eye movements. The cauterization of the scleral vessels and conjunctiva and the subconjunctival injection were the stages causing severe pain. The most frequent intraoperative complication was posterior capsule rupture in 6 eyes (1.8%). The satisfaction level was 95% for the patients and 90% for the surgeon.

CONCLUSION

Deep-topical, nerve-block anesthesia provides anesthesia with sufficient quality for small-incision manual ECCE.

Characterization of a New Animal Model for Evaluation of Persistent Postthoracotomy Pain

Chronic pain after thoracotomy is common, although its basis and therapy have not been well characterized. In this study we characterize the allodynic responses (mechanical and cold) as well as the histopathologic changes after thoracotomy and rib retraction in rats. The antinociceptive effect of systemic and intrathecal analgesics was also evaluated. Male Sprague-Dawley rats were anesthetized and the right 4th and 5th ribs surgically exposed. The pleura was opened between the ribs and a retractor placed under both ribs and opened 8 mm. Retraction was maintained for 5, 30, or 60 min. Control animals had pleural incision only. Beginning Day 2 postsurgery, animals were tested for mechanical allodynia using calibrated von Frey filaments and cold allodynia using acetone applied to the incision site. Two weeks after surgery, animals were tested for reduction of allodynia with intraperitoneal and intrathecal injections of analgesics. Intercostal nerve histology was examined at 14 days postsurgery. Allodynia developed in 50% of the animals with 60 min retraction but in only 11% and 10% of animals when the retraction time was 5 and 30 min, respectively, and in none of the control animals. Allodynic animals showed extensive axon loss in the intercostal nerves of the retracted ribs. Allodynia appeared by Day 10 in the rib-retraction model and lasted at least 40 days. Systemic morphine sulfate (50% effective dose [ED(50)], 1.06 mg/kg) and gabapentin (ED(50), 24.2 mg/kg), as well as intrathecal morphine (ED(50), 1.19 nmol), gabapentin (ED(50), 13.8 nmol), clonidine (ED(50), 72.7 nmol), and neostigmine (ED(50), 0.54 nmol) reduced allodynia. Rib-retraction in rats for 60 min produces allodynia that lasts more than 1 mo, and this allodynia is reduced by morphine, gabapentin, clonidine, and neostigmine. This new model may be useful for quantifying the efficacy of techniques to reduce the frequency and severity of long-term postthoracotomy pain.

Dose-ranging analgesic study of Prosorb diclofenac potassium in postsurgical dental pain

BACKGROUND

ProSorb diclofenac potassium (K) is a novel, liquid-filled rapid-dispersion formulation of the nonsteroidal anti-inflammatory drug diclofenac, placed into soft gelatin capsules. Its time to maximal plasma drug concentration has been shown to be approximately half, and its maximal plasma drug concentration nearly twice, that of immediate-release diclofenac K tablets.

OBJECTIVE

This study compared the analgesic dose-response relationship and tolerability of 3 doses of ProSorb diclofenac K and placebo in the treatment of pain after dental impaction surgery.

METHODS

This randomized, double-blind, double-dummy, placebo-controlled parallel-group study was conducted at 6 centers across the United States. Patients aged 18 to 65 years with moderate or severe pain after the removal of > or =1 impacted mandibular third molar were randomly assigned to receive a single dose of ProSorb diclofenac K 25, 50, or 100 mg or placebo. Pain intensity and relief were assessed up to 6 hours after dosing. Rescue treatment was allowed after 1 hour. Efficacy end points included the summed pain intensity difference over 3 and 6 hours (SPID3 and 6); total pain relief at 3 and 6 hours (TOTPAR3 and 6); median times to onset of perceptible and meaningful relief (analgesic onset) and rescue medication use (analgesic duration); and cumulative percentage of patients using rescue medication. Tolerability was assessed using vital sign measurements and spontaneous reporting of adverse events.

RESULTS

A total of 265 patients (154 women, 111 men; mean age, 23.3 years) were enrolled. All 3 ProSorb diclofenac K groups showed higher SPID6 and TOTPAR6 scores and longer median times to rescue medication use than the placebo group (all, P < 0.001). For these end points, a dose-response relationship was evident between the 100-mg dose and the 25- and 50-mg doses (P < or = 0.05); the 25- and 50-mg doses were similar. In the diclofenac groups, median onset times for first perceptible (< or =22.5 min) and meaningful (< or =53.0 min) relief were significantly more rapid than placebo (P < or = 0.01). Proportions of patients requiring rescue analgesic were < or =50.8% with diclofenac compared with 79.4% with placebo. Proportions of patients assigning a global evaluation of good or better was > or =68% with diclofenac compared with 21% for placebo. Tolerability was similar across all treatment groups.

CONCLUSION

In this study of patients treated for pain following dental impaction surgery, single doses of ProSorb diclofenac K 25, 50, and 100 mg were more efficacious than placebo with respect to reduction of pain. All 3 doses provided a rapid analgesic onset and were well tolerated.

[Beneficial effects of single dose multimodal epidural analgesia on relief of postoperative microdiscectomy pain]

We aimed to assess the efficacy of multimodal epidural analgesia in decreasing postoperative pain after microdiscectomy. Fourty patients, ASA physical status I or II, undergoing microsurgical lumbar discectomy were enrolled in this prospective, randomised, controlled, double-blinded study. 10 ml study solution consisting of 2 mg of morphine, 15 mg of bupivacaine, 80 mg of methylprednisolone, and 0.05 mg of adrenaline was prepared for epidural administration. At the end of the procedure but prior to wound closure, the surgeon inserted an 18-gauge epidural catheter into the epidural space. After closure of incision, patients were assigned to receive either study solution (Group E) or saline (Group C). The epidural catheter was then removed. Patient controlled analgesia with morphine was used for postoperative analgesia. Visual Anologue Scale (VAS) pain scores and morphine consumptions were lower in Group E. Time to first ambulation was shorter in Group E. Patients in Group E were more satisfied with their analgesic regimen. Single dose multimodal epidural analgesia administered after wound closure provided better postoperative analgesia after lumbar microdiscectomy.

Ultrastructural analysis of metallic debris and tissue reaction around spinal implants in patients with late operative site pain

STUDY DESIGN

Cross-sectional ultrastructural analysis of metallic debris as well as the tissue reaction surrounding spinal implants in patients with late operative site pain.

OBJECTIVE

To clarify the cause of late operative site pain by the ultrastructural analysis of the byproducts of metallic corrosion as well as the surrounding soft tissues.

SUMMARY OF THE BACKGROUND DATA

Late operative site pain has been identified as the most frequent cause of implant removal. Allergic reaction to metal as well as low-grade infection has been suggested as probable mechanisms.

METHODS

Fourteen spinal implants were removed because of late operative site pain. Tissues obtained from different zones surrounding these implants were analyzed by light microscopy, transmission electron microscopy, and scanning electron microscopy along with electron dispersion radiograph analysis.

RESULTS

No signs of infection were present. Either one of the 2 types of connective tissue (dense or loose) were found to surround the implants. Macrophage counts were most abundant in zone II (around pedicular screws) when compared to other zones (zone I: around the rods; zone III: around the transverse rod connectors). In contrast, particulate debris was more abundant and larger in size in specimens from zone III. Two types of metallic debris were identified. The rusty appearing particles contained mostly iron (Fe), whereas the black appearing particles were rich in chromium (Cr).

CONCLUSION

This study produced useful information regarding the production and distribution of particulate metallic debris around stainless steel spinal implants.

[Impact of surgery and trauma in developing chronic pain]

Surgery and trauma are recognized as important causes of chronic pain. In this manuscript, we analyzed the patients who visited our clinic with posttraumatic or delayed surgical pain complaints between January 2001 and January 2004. Identification and evaluation of pain were done as defined in the taxonomy of IASP. Duration and severity of pain as well as diagnosis and etiology were evaluated as suggested in the taxonomy. Our results showed that 107 out of 2866 patients (4 %) were diagnosed of having chronic pain related to the history of trauma or surgery. The age range of the patients was from 32 to 66 years with an average of 48 years. Male/female ratio was 35/72. The duration of pain varied. 15 % of the patients complained of pain lasting for 1 to 6 months, 67 % complained of pain lasting for 6 to 24 months, and 18 % complained of pain lasting more than 24 months. A significant amount of patients (72 %) complained of very severe pain, 21 % complained of moderate pain, and finally only 7 % complained of mild pain. The diagnosis of pain were as follows: radiculopathy and postlaminectomy pain in 48 %, neuropathic pain in 33 %, phantom pain in 12 %, carpal syndrome in 6 %, and thalamic syndrome in 1 %. Pathogenesis of pain was evaluated to be originating from peripheral nervous system in 56 %, muscle and skeletal system in 43 %, and central nervous system in 1 % of the cases. Additionally, fifty-nine percent of the cases complained of back pain. Long-term (?1 year) and continuous follow up of postoperative and posttraumatic pain during acute course may prevent a significant amount of chronic pain complaints.

Detection of bacterial DNA in painful degenerated spinal discs in patients without signs of clinical infection

A local inflammatory and potentially painful response, of which the ultimate cause is unknown, has been described in nervous tissues in contact with degenerated disc material in patients with low back and leg pain. With the rationale that a possible cause of such inflammation could be bacterial infection, we utilized PCR (polymerase chain reaction) amplification of the 16S rRNA (ribosomal RNA) gene followed by gene sequencing, to investigate whether bacterial DNA might be detected in the degenerative discs of 10 patients operated for disc herniation or post-discectomy syndrome. One patient with disc hernia harbored DNA homologous to Bacillus cereus, and in one patient suffering from post-discectomy syndrome, Citrobacter braaki/freundii DNA was detected. The finding demonstrates that 16S rRNA PCR can be a useful tool in search of bacterial DNA in degenerated discs, which in turn may be indicative of low-grade infection, manifesting itself only as pain rather than as clinical infection.

[The effects of application of rectal naproxen on postoperative analgesia, sedation and morphine use in heart surgery operations]

In this study, effects and side effects of application of rectal naproxen, combined with patient controlled intravenous morphine analgesia, were investigated in the elective coronary bypass operations for postoperative pain control, sedation and opioid use. Following the ethical committee approval and individual patient self consent, 40 patients, who underwent coronary artery bypass surgery were included in the study. A double blind study was performed by administering rectal naproxen to group N (n = 20) and placebo to group P (n = 20), at the end of the operation. Doses were repeated at the 12th hour postoperatively. Patient controlled intravenous morphine analgesia was performed to all patients for postoperative 24 hours. Postoperative pain and sedation levels were assessed, the side effects were noted. There was no difference between two groups with respect to their demographic features duration of surgery, extubation time and side effects (p > 0.05). With respect to group P, decrease in opioid use, better sedation and decrease in pain scores during both resting and coughing was seen in group N (p < 0.05). In conclusion, analgesia applied by addition of rectal naproxen to opioids achieved better pain management in selected patients after cardiac surgery.

Testicular pain after inguinal hernia repair: an approach to resection of the genital branch of genitofemoral nerve

BACKGROUND

The neuropathic groin pain after inguinal hernia repair is usually due to a neuroma of the ilioinguinal, iliohypogastric, or genitofemoral nerve. When the postherniorrhaphy pain symptoms include mostly testicular pain, then the genital branch of the genitofemoral nerve comes first in the differential diagnosis. Nerve blocks are helpful in determining which of the three nerves is implicated in the pain syndrome. Although the surgical approach to the ilioinguinal nerve is now well established, it has been difficult to identify the genitofemoral reliably enough to permit resection of this nerve.

STUDY DESIGN

Anatomic cadaver dissections of nerves exiting the lumbosacral plexus were performed. Their course was followed to their final terminations. Based on these findings, an operative approach was designed to address the involved nerve at a specific site. The results and outcomes were prospectively followed.

RESULTS

The present anatomic study identifies the site within the inguinal canal where the genital branch of the genitofemoral nerve may be identified. The designed operative approach points to the proximal site of the canal to be opened for an exposure. It also dictates that the nerve should be dissected and resected proximal to the surgical repair or mesh reconstruction, which allows its retroperitoneal placement. All four patients were relieved of their preoperative symptoms using this approach.

CONCLUSIONS

Severe and chronic testicular pain after inguinal hernia repair can be treated by a designed approach that identifies the genital branch of the genitofemoral nerve in the proximal inguinal canal, its resection point proximal to the previous operative field, and placement behind the peritoneum.

Preemptive meloxicam for postoperative pain relief after abdominal hysterectomy

OBJECTIVE

This study was conducted to evaluate the analgesic efficacy of meloxicam in abdominal hysterectomy.

METHODS

The study population consisted of 52 patients scheduled for total abdominal hysterectomy who were ASA 1 or 2 physical status female. Patients were allocated randomly to receive orally either 15 mg of meloxicam (Group M, n = 27) or placebo (Group P, n = 25) before anesthesia induction. After intravenous administration of 1.5 mg kg(-1) of tramadol, anesthesia was induced with an intravenous loading dose of 1-2 mg kg(-1) propofol. Anesthesia was maintained on intravenous infusion of propofol at 6-12 mg kg(-1) h plus tramadol at 1 mg kg(-1) h(-1), vecuronium, and a 2:1 nitrous oxide-oxygen mixture.

RESULTS

The relative propofol consumption was lower in Group M than in Group P, (p < 0.05). The time for analgesic rescue decreased in the order Group M > Group P (p < 0.01). The degree of sedation was similar between the groups (p > 0.05) and the visual analog scores (10-cm scale) and verbal rating scale data differences were present in the first 2 h only (p < 0.05). When side-effects were evaluated nausea and vomiting were found to be lower in group M than in group P (p < 0.05).

CONCLUSION

Preemptive meloxicam provided better postoperative analgesia than placebo.

Impact of the preservation of the intercostobrachial nerve in axillary lymphadenectomy due to breast cancer

This study evaluated the relationship between preservation of the intercostobrachial (ICB) nerve and pain sensitivity of the arm, the total time of the surgery, and the number of dissected nodes in patients submitted to axillary lymphadenectomy due to breast cancer. An intervention, prospective, randomized, and double blind study was performed on 85 patients at the State University of Campinas, Brazil, from January 1999 to July 2000. The patients were divided into two groups, according to whether the ICB nerve was preserved or not. The surgeries were performed by the same surgeons, utilizing the same technique. The postoperative evaluations were performed at 2 days, 40 days, and 3 months. The pain sensitivity of the arm was evaluated through a specific questionnaire (subjective evaluation) and through a neurologic examination (objective evaluation). The surgical technique presented a feasibility of 100% and preservation of the ICB nerve was related to a significant decrease in the pain sensitivity of the arm, both in the subjective and objective evaluations. After 3 months, in the subjective evaluation, 61% of the patients were asymptomatic in the ICB nerve preservation group, with 28.6% in the nerve section group (p<0.01). In the objective evaluation, 53.7% of the patients presented normal neurologic examination in the ICB nerve preservation group, with 16.7% in the nerve section group (p<0.01). No significant difference was observed in the total time of the surgery (p=0.76) and the number of dissected nodes between the two groups (p=0.59). Local relapse was not observed in any group after 36 months of follow-up. These data support that preservation of the ICB nerve is feasible and leads to a significant decrease in the alteration of pain sensitivity of the arm, without interfering with the total time of the surgery, the number of dissected nodes, and local relapse rate.

Randomized controlled study of laparoscopic total extraperitoneal versus open Lichtenstein inguinal hernia repair

BACKGROUND

Whereas open anterior inguinal herniorrhaphy is a time-tested, safe, and well-understood operation with a high success rate, laparoscopic techniques of inguinal hernia repair are fairly recent. Consequently, short- and long-term outcomes are still being evaluated. Few studies have compared laparoscopic extraperitoneal inguinal hernia repair with tension-free open hernia repair. The current study was conducted to compare complications, operative time, postoperative pain, length of hospital stay, and return to work between open tension-free mesh Lichtenstein (open) repair and laparoscopic total extraperitoneal (TEP) repair.

METHODS

In a prospective randomized study, open hernia repair was performed in one group (n = 25), and TEP repair using a large mesh was performed in another (n = 25). Then intraoperative and postoperative complications and results were compared.

RESULTS

The mean operative time in the TEP group was 75.72 +/- 31.6 min, which was significantly longer than the mean operative time in the open group (54 +/- 15) min (p <0.001). The mean pain scores in the TEP group were 2.64 +/- 1.4 at 12 h and 1.76 +/- 1.4 at 24 h. These scores were significantly lower than the corresponding scores of 3.52 +/- 1.7 (p <0.04) and 2.74 +/- 1.5 (p <0.01) in the open repair group. The mean postoperative analgesic dose was 2.6 +/- 2.3 in the TEP group, which was significantly lower than in the open group 5.76 +/- 3.5 (p <0.001). There was no major complication in either group. The time until return to work was significantly lower in the TEP group (12.8 +/- 7.1) days versus 19.3 +/- 4.3 days; than in the open group (p <0.001). In terms of cosmetics, all 25 patients (100%) in TEP group rated themselves as "highly satisfied," as compared with 7 patients (28%) in the open group (p <0.001). After a mean follow-up period of 13 months (range, 9-18 months), no recurrence was seen in either of the two groups.

CONCLUSION

In terms of complications and short-term recurrence, TEP repair is comparable with open repair. Moreover, TEP is significantly less painful in the early postoperative period, leading to earlier ambulation than open repair. Additionally, TEP results in significantly earlier return to work and better cosmetic results. Currently, TEP seems to be a better alternative than the existing open repair, provided the long-term recurrence rates are comparable. Despite the fact that TEP was a new procedure for the surgeon and the study was conducted during the learning phase, the results are comparable with those in the world literature.

Intrapleural analgesia following thoracoscopic sympathectomy for palmar hyperhidrosis: a prospective, randomized trial

BACKGROUND

Reports on intrapleural analgesia (IPA) are conflicting. The current study assessed the effect of a single-dose thoracoscopic bilateral intrapleural anesthetic administration on the immediate postoperative recovery room and 24-h pain control.

METHODS

Fifty patients with primary palmar hyperhidrosis were randomly classified into two groups to receive either 20 ml of 0.5% bupivacaine and 5 mg/ml epinephrine or 0.9% NaCl in each thoracic cavity at the end of thoracoscopic T2-T3 sympathectomy. The degree of early postoperative pain was estimated by visual analog scale (VAS). The 24-h parenteral opioid analgesic requirement was recorded.

RESULTS

The immediate postoperative VAS score (1.46 +/- 0.41 vs 2.0 +/- 0.61, p = 0.03), opioid consumption (0.42 +/- 0.36 vs 0.65 +/- 0.28, p = 0.0133), and 24-h opioid consumption (1.02 +/- 0.80 vs 1.48 +/- 0.84, p = 0.05) were significantly reduced following IPA compared to those of the control group.

CONCLUSION

IPA is a simple and effective means for postoperative pain control following thoracoscopic upper dorsal sympathectomy.