The various indications for PVB are summarized in Table 48-1 and described in detail next. The most common indications include breast surgery, hernia repair, and thoracic surgery. A systematic review of the literature, which included 8 randomized clinical trials evaluating PVB for breast surgery or herniorrhaphy, concluded that PVB for surgical anesthesia is associated with less pain during the immediate postoperative period, as well as less postoperative nausea and vomiting and greater satisfaction as compared with general anesthesia.88 A systematic review of randomized trials evaluating regional anesthetic techniques for post-thoracotomy analgesia concluded that continuous paravertebral block was comparable to thoracic epidural analgesia with local anesthetic, but was associated with a reduced incidence of hypotension and a reduced incidence of pulmonary complications compared with systemic analgesia, whereas thoracic epidural analgesia was not.89
The use of PVB for postoperative analgesia after thoracoscopy or thoracotomy has been investigated in both adults36,37,41,63-67,90-95 and children.80,96 A commonly used approach involves preoperative PVB to provide intraoperative analgesia in addition to a continuous local anesthetic infusion via a paravertebral catheter for postoperative analgesia. Preoperative PVB is performed using either a single- or multiple-level injection technique with the goal to provide sensory block from T4 to T9. A paravertebral catheter can be placed preoperatively by the anesthesiologist percutaneously, intraoperatively by the thoracic surgeon under video assistance during thoracoscopy41 or in combination with the anesthesiologist,42 or under direct visualization at the time of chest closure.36-40
Hill et al92 investigated multilevel PVB after thorascopic procedures in a prospective, double-blinded, randomized, placebo-controlled study. The benefits of PVB included less intraoperative fentanyl (p < .003), reduced cumulative opioid consumption (p < .03), and lower maximum pain scores at 6 hours (p < .02). No significant difference in cumulative morphine consumption was reported at 12 or 18 hours after block placement, and there was no difference in spirometry, cortisol levels, or cytokine production between groups. A prospective, randomized, blinded, placebo-controlled study by Vogt et al94 demonstrated a significant difference in VAS scores at rest and coughing over a 48-hour time course with single-level injection PVB (p < .05). There was no difference with regard to peak expiratory flow rate at 24 and 48 hours between groups. Kaya et al95 demonstrated that preoperative multiple-level injection PVB for postoperative analgesia after video-assisted thorascopic surgery procedures was associated with lower intraoperative fentanyl use (p < .01), longer time to first analgesic requirement (p < .05), lower VAS at first analgesic requirement (p < .01), lower maximum VAS pain scores during the 48-hour study period (p < .01), improved patient satisfaction (p < .05), decreased time to first mobilization (p < .01), and decreased time to hospital discharge (p < .05).
In a prospective, randomized, placebo-controlled trial, Berrisford et al63 documented the beneficial effects of continuous PVB for thoracotomy patients. They found lower pain scores (p < .01), reduced opioid consumption (8.6 mg vs 119 mg over 5 days), fewer postoperative pulmonary complications (8% vs 52.4%; p < .05) and better preservation of pulmonary function (p < .01) in the group who received bupivacaine compared with saline. Comparable results were obtained in a number of studies with similar design64-67 and a non–placebo-controlled study.91 The moment of insertion of PVB catheter, before or after rib-spreading, did not affect analgesic quality after thoracotmy.97 An additional advantage of PVB involves a potential reduction in the incidence of post-thoracotomy neuralgia.61
Continuous PVB has a number of theoretical advantages over both continuous interpleural and intercostal blocks. PVB more reliably achieves block of the dorsal ramus of the spinal nerve. This is important because much of the pain that results from thoracotomy stems from the paraspinal muscles and other areas innervated by the dorsal ramus. In addition, greater cephalocaudal spread of local anesthetic occurs and results in more extensive block with continuous PVB compared with the other 2 modalities.98 Despite these theoretical advantages, prospective studies comparing continuous PVB versus interpleural99 and intercostal100 infusions of local anesthetic failed to show a difference between groups in pain scores and opioid consumption. Nevertheless, PVB was associated with better preservation of lung function as measured by forced vital capacity and FEV1.99
PVB continuous catheters have been compared with incisional (subcutaneous) catheters and a combination of the 2 for postoperative analgesia after thoracotomy.37 VAS reports were lower at rest, on coughing, and on movement at 12 (p <.01, p < .05, and p < .05, respectively) and 24 hours (p < .05, p < .05, and p < .05, respectively) after surgery when incisional catheters were used to supplement paravertebral analgesia. However, excluding the first 4 hours, there was no significant difference in daily morphine use to improve analgesia between the 3 groups. There was no significant difference in spirometry testing observed between groups.
Continuous PVB has also been compared with intermittent boluses of epidural morphine for post-thoracotomy analgesia. Dauphin et al38 found that these 2 modalities resulted in similar pain scores and supplemental intravenous morphine consumption.
A number of prospective, randomized trials exist comparing continuous PVB (local anesthetic alone) versus epidurals (local anesthetic with or without opioid).36,40,69,90,101,102 In a study by Richardson et al,101 the group who received PVB had lower postoperative pain scores at rest (p = .02) and with coughing (p = .0001) as well as lower cumulative morphine consumption over 48 hours (p ≤ .008). However, other studies36,40,90 failed to replicate these findings. Messina et al90 demonstrated increased morphine consumption with PVB as compared with epidural with local anesthetic and opioid infusion; however, VAS scores were not significantly different between the 2 groups. Opioid-related side effects were not reported. Gulbahar et al36 found no significant difference between the 2 groups with regard to VAS, serum cortisol and glucose levels, necessity for additional analgesia, and hospital stay duration. There was a significant difference in side effects, with no side effects in the PVB group (p < .01).36 A number of investigators have shown a lower incidence of side effects such as nausea,36,101 vomiting,36,101 hypotension,36,69,101 and urinary retention36,40,69,101 with PVB as compared with epidurals.
Studies of the effects of PVB on postoperative lung function have been conflicting. Richardson et al101 documented that the postoperative peak expiratory flow rate as a fraction of preoperative value was 0.73 in the PVB group compared with 0.54 in the epidural group (p < .004), suggesting better preservation of lung function with PVB. In contrast, Messina et al90 reported improved spirometry values at 72 hours with return of forced vital capacity to 83% of the preoperative value in the epidural group, as compared with 31% in the paravertebral group. Other studies36,102 found no significant difference between the 2 analgesic modalities.
In addition to their utility for thoracoscopies and thoracotomies, PVB has also been used successfully for other indications. In a prospective, randomized, placebo-controlled trial of patients having pleurectomy, Mozell et al103 established that continuous PVB with bupivacaine provided lower pain scores, reduced opioid consumption, and better preservation of pulmonary function than placebo. In a retrospective study by Patel et al,104 the addition of PVB to general anesthesia after first rib resection demonstrated decreased postanesthesia care unit (PACU) pain scores. PVB has also been used to provide analgesia for rib fractures. Mohta et al105 demonstrated that continuous PVB provided comparable analgesia and respiratory function to continuous thoracic epidural analgesia (TEA) in patients with unilateral multiple rib fractures with a decreased incidence of hypotension. There was no significant difference in VAS scores at rest and on coughing, respiratory rate, morphine requirement, peak expiratory flow rate, incidence of pulmonary complications, infusion duration, length of intensive care unit stay, and length of hospital stay.105 Additionally, PVB has been used to provide analgesia for rib fractures in patients with head106 and spinal cord107 injuries. In patients with head injury, paravertebral analgesia reduced the need for potentially sedating analgesics and enhanced neurologic assessment.106 Unilateral PVBs were administered instead of an epidural block in patients with lumbar spinal cord injury because the PVB enhanced assessment of lumbosacral spinal cord function.107 Moreover, paravertebral analgesia provides quality analgesia and has beneficial effects on pulmonary function among patients with traumatic chest injury.108 Additional applications have been in the management of chest pain caused by pleural effusion.109
PVBs can be used as the sole intraoperative anesthetic or as an analgesic supplement to general anesthesia for breast surgery. The block may be performed as a single-level injection or as injections at multiple levels. The dermatomal levels blocked depend on the surgical procedure (Table 48-1). Block of T2-T6 is required for mastectomy. When mastectomy and axillary dissection is scheduled, extending the block to include the T1 dermatome is essential. Supplementing with a superficial cervical plexus block can also enhance analgesia at the superior aspect of the incision. Breast biopsy requires block of the dermatome involved in addition to 1 level cephalad and 1 level caudad. Long-acting local anesthetics such as bupivacaine can provide postoperative analgesia for up to 23 hours.110
A number of prospective, randomized trials exist comparing general anesthesia versus PVB for breast surgery.43,45,46,59,68,111,112 Pusch et al68 performed a single-injection block with bupivacaine using the loss-of-resistance technique at T4 in patients having breast cancer surgery. They found rapid onset of block, with skin incision occurring within 15 minutes of the block. They also documented a shorter emergence time in the group who had PVB (p < .01). The PVB group had lower pain scores during the 13 hours of the study (p < .05) and received fewer analgesics (p < .01). There was less painful restricted motion (p < .001) and a reduced incidence of postoperative nausea and vomiting (p < .05) in the PVB group. Paravertebral anesthesia with propofol sedation was inadequate in 6% of patients; however, supplemental analgesia with intravenous fentanyl was sufficient to avoid conversion to general anesthesia. Naja et al46 used a nerve stimulator and performed injections at multiple levels with a mixture of lidocaine, bupivacaine, epinephrine, fentanyl, and clonidine. They showed an analgesic benefit for the first 5 days postoperatively and also documented a shorter length of hospital stay among patients who received PV (p < .01). Klein et al43 studied patients having unilateral or bilateral cosmetic and reconstructive breast surgery and also showed similar benefits, including lower verbal pain scores up to 72 hours after surgery. In addition, they were able to reduce intraoperative induction time from 24 minutes with general anesthesia to 4 minutes with PVBs by using a preoperative block area. Terheggen et al45 studied patients having minor breast surgery and performed PVB with bupivacaine via a catheter placed at T3-T4. The PVB reduced intraoperative fentanyl requirements and lowered postoperative pain scores only in the first 90 minutes postoperatively for this group of patients having surgery that may be considered less stimulating. Boughey et al111 compared general anesthesia with general anesthesia with multilevel PVB at T1 to T6 for patients undergoing breast cancer surgery. This was a prospective study in follow-up to a retrospective analysis that demonstrated improved postoperative analgesia up until the morning after surgery and a decreased proportion of patients requiring overnight stay after major breast operations.111 The prospective study demonstrated decreased pain scores and a greater percentage of pain-free patients at 1 hour (1 vs 3, p < .014; 44% vs 17%, p < .006) and 3 hours (0 vs 2, p < .001; 54% vs 17%, p < .005) after surgery; however, at 6 hours the difference was no longer evident. The overall worst pain score was lower with PVB (3 vs 5, p < .02), and there was a greater number of subjects in the PVB group reporting to be pain-free during hospital stay (33% vs 12%, p < .032). At 24 hours, there were more subjects reporting to be pain-free in the general anesthesia–alone group (23% vs 54%, p < .011), which might be representative of inadequate analgesia with block resolution. There was no difference in opioid consumption, nausea/vomiting, and hospital length of stay between groups. This study was limited in that it did not include a standardized surgical procedure. An underpowered subgroup analysis of the more extensive surgeries failed to demonstrate a difference between groups at any time. Moller et al112 in a prospective, randomized, double-blind, placebo-controlled study also demonstrated duration of postoperative analgesia provided with PVB to be less than that described in previous studies. Intraoperatively, PVB was associated with a significant decrease in intraoperative fentanyl (p < .0001) and propofol (p < .001). In the PACU, PVB was associated with decreased opioid consumption p < .001) and improved pain control (patients reporting VAS <3; p < .0001). There was no difference in postoperative nausea and vomiting between groups. No benefits were demonstrated beyond the PACU. Another, randomized, placebo-controlled trial44 studied patients scheduled for breast cancer surgery receiving single-injection PVB at T3 with bupivacaine 0.5% (1.5 mg/mL) or saline before general anesthesia. Pain scores were low in both groups; however, patients receiving PVB with bupivacaine had less postoperative pain in the PACU and up to 12 hours after surgery, as measured by longer time to first analgesic (20 min vs 10 min; p < .019) and lower VAS (PACU, 3.0-1.7 vs 4.8-1.4, p <.025; 12 h, p < .096). Postoperative pain was minimal in both groups of this study, as evident by low PACU pain scores and zero opioid consumption after discharge from PACU in either group. There was no significant difference in the number of patients with postoperative nausea and vomiting (PONV) between groups. Iohom et al59 demonstrated improvement of postoperative VAS pain scores with PVB continuous catheters at rest up to 12 hours (p < .035) and movement at 12 hours and on postoperative days 1, 2, 3, 4, and 5 (p < .04.)
A prospective comparison of continuous wound infiltration with ropivacaine versus single-level injection PVB after modified radical mastectomy113 demonstrated low pain scores in both groups. PVB was associated with reduced pain scores at 4 hours (p < .02) and less PONV. Continuous wound infiltration was associated with reduced pain scores at 16, 20, and 24 hours. There was no difference in opioid consumption between groups at any time point.
PVB may be associated with a reduced development of chronic postsurgical pain after breast surgery. In a study by Iohom et al59 at 10 weeks, 80% of patients (12 of 15) not receiving PVB continuous catheters developed chronic postsurgical pain as compared with 0% (0 of 14) in those receiving PVB catheters (p < .009). Preoperative PVB may reduce the incidence of chronic pain 1 year after breast cancer surgery.60
PVB can be used for surgical anesthesia or for analgesia as a supplement to general anesthesia for inguinal, umbilical, or incisional hernia repair. When performed for inguinal hernia repair, block of the T10 through L2 dermatomes is typically required. This can be achieved by a single-level injection in the low thoracic PVS or by injections at multiple levels.
PVB may be used as the sole anesthetic for inguinal hernia repair.114,115 Klein et al114 demonstrated that bupivacaine PVB provided surgical anesthesia within 15 to 30 minutes and prolonged postoperative analgesia with a mean time to first opioid of 22 hours. In a study by Weltz et al,115 the failure rate requiring conversion to general anesthesia was 6.7%; however, these investigators documented low pain scores for 48 hours postoperatively.
Studies have evaluated the efficacy of PVB compared with other anesthetic techniques, including general anesthesia, spinal anesthesia, ilio-inguinal block, and local field block for inguinal hernia repair. As compared with general anesthesia, multilevel PVB from T9 to L1 was associated with shorter time to home readiness, greater phase 1 PACU bypass, less postoperative pain, faster ambulation, and quicker discharge home.116 Single-level injection PVB at L1 demonstrated shorter time to ambulation, increased recovery room bypass, and decreased postoperative urinary retention as compared with spinal anesthesia with 12.5 mg of 0.5% bupivacaine.117 Multilevel PVB from T9 to L1 versus unilateral spinal anesthesia with 8.0 mg of 0.5% bupivacaine provided statistically significant shorter hospital stays with shorter time to home readiness (with and without voiding), shorter discharge time, and prolonged postoperative analgesia with a mean time to first analgesic of 16 hours as compared with 7 hours in the spinal group.118 Naja et al119 compared multilevel PVB from T12 to L2 versus general anesthesia versus spinal anesthesia. Again, patients in the PVB group had a shorter duration of hospital stay (1.2 d vs 2.9 d for general anesthesia vs 2.5 d for subarachnoid block; p < .0001), better postoperative analgesia, and a lower incidence of postoperative nausea and vomiting (0 vs 21% for general anesthesia vs 19% for subarachnoid block; p < .001). In a randomized trial, Wassef et al120 compared lidocaine PVB versus lidocaine/bupivacaine field block. The PVB was associated with less frequent intraoperative supplementation (20% vs 41%; p < .01), a lower rate of conversion to general anesthesia (0 vs 6.7%), and greater patient satisfaction (p < .05).
Alternatively, PVB can supplement another primary anesthetic technique (ie, general or spinal anesthesia) to provide postoperative analgesia. In a prospective, randomized study of subjects undergoing inguinal hernia repair under general anesthesia, Klein et al121 compared postoperative analgesia from ropivacaine PVB with ilioinguinal-iliohypogastric nerve blocks with wound infiltration. They found reduced opioid consumption intraoperatively (p = .02) and in the PACU (p = .002), as well as a lower antiemetic use (p < .001) in the PVB group; however, there was no subsequent difference in pain scores and opioid use. In children undergoing inguinal herniorrhaphy under general anesthesia, multilevel PVB from T12 to L1 as compared with general anesthesia with systemic analgesia (GA/SA) demonstrated improved postoperative analgesia during the first 48 hours, increased same day discharge (80% PVB group vs 52% GA/SA), and greater parental and surgeon satisfaction.122 As compared with ilio-inguinal block, multilevel PVB from T12 to L2 in children undergoing inguinal herniorrhaphy under general anesthesia demonstrated a significant improvement in intraoperative hemodynamic stability, postoperative analgesia with decreased consumption of analgesic drugs during the first 36 hours after surgery, and again greater parental and surgeon satisfaction.123
Ozkan et al124 comparing 2-level (T10, L1) PVB versus 4-level (T10-L1) PVB demonstrated shorter block performance time (5 min [SD 1] vs 16 min [SD 4]; p < .001) with 2-level injection but no difference in the other parameters investigated, including intraoperative propofol and remifentanil use, VAS scores, postoperative analgesics consumed, sensory block duration adverse effects, PONV, and patient satisfaction.
When PVB is used for umbilical hernia repair of moderate size, a bilateral block from T9 to T11 is required. In a nonrandomized study, Naja et al56 compared PVB versus general anesthesia. PVB was performed using a nerve stimulator and a mixture of lidocaine, bupivacaine, epinephrine, fentanyl, and clonidine. Interestingly, 10% of patients in the PVB group required supplemental analgesia due to unanticipated extension of the surgical field. Nevertheless, PVB had a number of benefits, including lower pain scores and reduced opioid requirements up to 48 hours (p < .001). PVB was also associated with a decreased incidence of PONV (3.3% vs 26.7%; p < .05) and shorter length of hospital admission (2.3 d vs 4.1 d; p < .05).
Finally, PVB can be used for incisional hernia repair and are performed according to the dermatomal levels involved. Block from T8 to T12 has also been used for ileostomy closure.125
Unilateral PVB is well suited to provide postoperative analgesia after renal surgery. A PVB continuous catheter can be placed preoperatively, or alternatively, a catheter can be placed under direct vision by the surgeon at the time of wound closure.126 In a randomized, prospective, placebo-controlled trial, Awwad and Atiyat126 found reduced pain scores for 3 days (p < .026) and decreased opioid consumption (13.3 mg vs 40.13 mg over 3 d; p < .001) in the continuous PVB catheter with bupivacaine versus saline. Lonnqvist127 and Lonnqvist and Olsson128 have used continuous PVB in children having renal surgery. In a nonrandomized study, they compared the postoperative analgesia obtained from paravertebral versus epidural bupivacaine128 and found decreased opioid consumption in the PVB group. In a case report of 30 patients, PVB as a part of a multimodal analgesia regimen provided significant opioid sparing as compared with previous studies129,130 after hand-assisted laparoscopic nephrectomy.131
Jamieson and Mariano132 reported pain scores of zero for 24 hours and no opioid rescue analgesia in 2 patients undergoing lithotripsy under PVB.
Few studies exist evaluating the efficacy of PVB for postoperative analgesia after open cholecystectomy by subcostal incision. Giesecke et al62 suggest that PVB reduces the stress response to surgery; however, Bigler et al87 found no benefit from continuous PVB when compared with thoracic epidural. More recently, PVB has been used to provide postoperative analgesia for laparoscopic cholecystectomy. In a prospective, randomized study, Naja et al133 randomized patients receiving general anesthesia to have PVB or opioid analgesia. Although there was no difference between groups in time to first oral intake or length of hospital stay, patients who received PVB had lower pain scores (p < .05), reduced opioid consumption over 36 hours (p < .05), and a decreased incidence of PONV (p < .05). Paleczny et al134 in a randomized, prospective study compared general anesthesia alone with PVB performed before the induction of general anesthesia. PVB demonstrated a significantly lower mean pain score during the first 72 hours after surgery (p < .005) and improved patient satisfaction.
Splinter and Thompson135 demonstrated in children (3-16 y) undergoing appendectomy that PVB T11 to L1 using ropivacaine 0.2% 0.25 mL/kg with 1:200 000 epinephrine was associated with decreased opioid consumption (p < .001) with an increased time to first opioid dose (p < .001). There was no significant difference in vomiting and no other adverse effects observed in the 2 groups.
PVB can be used as an adjunct to other peripheral nerve blocks or as the sole regional technique for the treatment of postoperative pain in orthopedic patients. In patients receiving an interscalene brachial plexus block for shoulder surgery, the addition of T1 to T2 PVB provides more complete shoulder analgesia. And, in combination with a lumbar plexus block, T11 to T12 PVB provides more comprehensive analgesia for patients having hip surgery. Alternatively, PVB from T12 to L4 and from L2 to S1 has been used to provide postoperative analgesia after total hip and knee arthroplasty, respectively.136 For hip arthroscopy, Lee et al presented 2 cases in which they performed 2-level (L1 and L2) PVB with 5 mL of ropivacaine 0.5% preoperatively in combination with general anesthesia and injection of 20 mL of 0.25% bupivacaine with epinephrine into the hip joint by surgery at the end of the procedure. This regimen provided postoperative analgesia of approximately 36 hours and greater with no opioid requirement.
Bilateral PVB from T11 to L2 can be used to provide intraoperative anesthesia and postoperative analgesia for patients having bone marrow aspiration. This technique provides an alternative option when general and/or spinal anesthesias are contraindicated (ie, mediastinal tumor and chemotherapy-related thrombocytopenia).
Cardiac and Vascular Surgery
PVB has been used both for analgesia after cardiac surgery as well as peripheral vascular procedures. In a prospective, observational study, Canto et al137 performed continuous bilateral ropivacaine PVB at T3 to T4 for patients having open-heart surgery with cardiopulmonary bypass. They reported excellent analgesia, a low complication rate, and facilitation of early tracheal extubation. Moderate hypotension and bradycardia were repeatedly observed and presumed due to sympathectomy; however, dopamine support was required in only 6.4%.
Bilateral T4 to T5 continuous PVB has also been successfully used for postoperative analgesia after minimally invasive coronary artery bypass138 and may facilitate early extubation.139 In a prospective, randomized trial, Dhole et al140 compared continuous PVB versus epidural and found no significant differences between the techniques with respect to analgesia.
A prospective randomized study in patients undergoing elective robotic-assisted coronary artery bypass grafting comparing thoracic epidural analgesia with PVB revealed no significant difference with regard to hemodynamics, arterial blood gases, pulmonary functions, and analgesia.141
Thoracic PVB with mild sedation was successfully used for implantable cardioverter-defibrillator and laser lead extraction in a patient who had a high opioid tolerance and desired prolonged analgesia.142
Richardson et al143 described paravertebral analgesia after major abdominal vascular surgery in an observational study. They placed bilateral PVB catheters at T10 in 8 patients and administered an infusion of bupivacaine. The continuous PVB provided excellent postoperative analgesia with preserved hemodynamic stability.
A retrospective review comparing paravertebral blockade with propofol sedation with general anesthesia for elective endovascular abdominal aortic aneurysm repair demonstrated decreased intraoperative hypotension (p < .05) and blood pressure lability (p < .01), as well as postoperative nausea (p < .01).144
A prospective, randomized, placebo-controlled study compared bilateral PVB injection of 25 mL of 0.25% bupivacaine with epinephrine to saline before induction of general anesthesia in 24 patients undergoing right lobe donor hepatectomy. PVB was associated with a 50% decrease in opioid consumption, a significant increase in time to rescue analgesia, and decreased PONV.
In a case report, Ho et al146 described the use of a right thoracic paravertebral catheter for hepatectomy and cite their preference for this technique over epidural analgesia in patients who have or may develop a coagulopathy.
In an additional case report, Hall and Leach147 illustrated the use of continuous paravertebral analgesia for the pain associated with a traumatic liver fracture managed conservatively.
In a feasibility study performed by Culp et al,148 PVB at T8 to T9 and T9 to T10 under fluoroscopic guidance in combination with intravenous sedation was successfully performed for 10 consecutive patients undergoing biliary drainage procedures. This group also performed multilevel PVB injection with 15 mL of 0.25% bupivacaine at T7 and T9 for analgesia after liver mass radiofrequency ablation, with no additional analgesic requirements. Sensory blockade of the T4 to T12 dermatomes was reported.149
A retrospective study of 100 patients undergoing radical retropubic prostatectomy under general anesthesia compared 50 patients (group 1) receiving local anesthetic wound infiltration with 30 mL of 0.25% bupivacaine, intravenous ketorolac, and opioids for postoperative pain management with 50 patients (group 2) who had received an amended analgesia protocol to include, in addition to the preexisting protocol, the use of preoperative, multiple-injection PVB at T10 to T12 bilaterally and a single preoperative oral dose of a COX-2 inhibitor. The study suggested that the analgesic protocol of group 2 might significantly reduce intraoperative and postoperative opioid requirements and reduce hospital length of stay.
Labor Analgesia for Obstetrics
Bilateral PVB has been used to provide analgesia for laboring obstetrical patients in whom epidural anesthesia is impossible or contraindicated. In a case series, Nair and Henry150 described using bilateral T11 and T12 PVB to obtain labor analgesia for patients with coagulation abnormalities (prolonged bleeding time, syndrome of hemolysis, elevated liver enzymes, and low platelets) and lumbar spinal anomalies (neuroblastoma, spina bifida occulta). Suelto151 underlines the limitation of this technique in providing analgesia for the second stage of labor as well as for cesarean section.
Several authors have published descriptions of the use of PVB in the management of chronic pain. Kirvela and Antila152 provided retrospective information on 32 patients having 281 PVBs for chronic chest wall pain. Results were similar for those patients with post-thoracotomy chest pain and those with postmastectomy pain. Among the thoracic surgical patients, immediate pain relief occurred in 99% of cases; however, prolonged pain relief was rare. Fifty-eight percent were pain-free at 1 month, 30% at 2 months, 8% at 4 months, and only 3% at 5 months. Among the breast cancer patients, 88% were pain-free for less than 1 month and only 6% were pain-free for more than 5 months. Antila and Kirvela 153 observed similar results in a population of patients who had chronic thoracic pain related to malignant disease with poor prognosis. PVB may offer a useful treatment for thoracic myofascial pain syndrome refractory to traditional therapeutic approaches.154 Limited data exist on the use of PVB for pain relief from acute herpes zoster155 and post-herpetic neuralgia.156