André P. Boezaart

Dysphagia Following Anterior Cervical Arthrodesis Is Associated with Continuous, Strong Retraction of the Esophagus

BACKGROUND The prevalence of dysphagia after anterior cervical decompression and arthrodesis is estimated to be 50% within one month and 21% at twelve months. However, its exact etiology is not well understood. The objective of the present study was to explore the relationship between intraoperative intra-esophageal pressure due to surgical retraction, esophageal mucosal blood flow at the level of surgery, and postoperative dysphagia. Our hypothesis was that sustained elevated pressure on the esophagus during anterior cervical arthrodesis is associated with postoperative dysphagia. METHODS Seventeen selected patients scheduled for anterior cervical arthrodesis were studied. Throughout the procedure, intraluminal pressure in the upper esophageal sphincter was measured (mm Hg) with a custom-made manometer probe and mucosal perfusion was measured at the level of surgery with a laser Doppler flowmeter. The type of retraction chosen by the surgeon was noted. Postoperatively, the patients were specifically evaluated for dysphagia on the first postoperative day and at six weeks, three months, and six months postoperatively with use of the M.D. Anderson Dysphagia Inventory. RESULTS Four of the eleven patients who had dynamic retraction and five of the six patients who had static retraction during surgery had postoperative dysphagia. In the group of patients with dysphagia, the average M.D. Anderson Dysphagia Inventory score decreased from 93.8 +/- 12.1 preoperatively to 67.7 +/- 11.4 on the first postoperative day (p < 0.001). The patients with dysphagia had a significantly higher average intraluminal pressure (60.8 +/- 54.3 compared with 54.4 +/- 51.8 mm Hg; p < 0.0001) as well as significantly lower average mucosal perfusion (26.1 +/- 18.1 compared with 40.8 +/- 26.2 tissue perfusion units; p < 0.0001) in comparison with the asymptomatic patients. CONCLUSIONS Patients with dysphagia following anterior cervical arthrodesis were exposed to higher intraoperative esophageal pressure and decreased esophageal mucosal blood flow during surgical retraction as compared with patients without dysphagia. In this small series, dynamic retraction seemed to be associated with a lower prevalence of postoperative dysphagia.

At the cords, the pinkie towards: interpreting infraclavicular motor responses to neurostimulation

Identification of elicited muscle twitches while performing infraclavicular block of the brachial plexus is often confusing but is critical for success of the block. An easily defined endpoint when evaluating these motor responses to neurostimulation is essential, as it is necessary to block the appropriate cord or cords. In addition to an extensive review of the motor and sensory neuroanatomy of the upper extremity, we describe an easy method to learn and remember the motor response to stimulation of each of the cords of the brachial plexus. If the arm is positioned in the anatomical position, the 5th digit (pinkie) moves laterally (pronation of the forearm) when the lateral cord is stimulated, posteriorly (extension) when the posterior cord is stimulated, and medially (flexion) when the medial cord is stimulated. The pinkie thus moves “toward” the cord that is stimulated.

Epidural Spread After Continuous Cervical Paravertebral Block: A Case Report

Background and Objective: This report illustrates epidural spread after continuous cervical paravertebral block (CCPVB). By fluoroscopy, it also explains the mechanism of the complication. Case Report: A healthy 22-year-old male developed bilateral upper-extremity motor weakness immediately after placement of a continuous cervical paravertebral block for postoperative pain control after shoulder stabilization surgery. The tip of the stimulating catheter was demonstrated in the C7 neuroforamen. Contrast injected through the catheter demonstrated epidural spread. The contralateral block resolved after 4 hours and the patient suffered no respiratory embarrassment or other untoward sequelae. Conclusion: Continuous cervical paravertebral block is a relatively new, but generally well-accepted, modality for postoperative pain control after major surgery to the upper limb. Epidural spread is recognized as a complication. In this particular case, medial placement of the catheter was possibly caused by unintentional medial direction of the bevel of the Tuohy needle. Meticulous attention to the direction of the needle bevel and early recognition and management of adverse events are mandatory. The same principles may apply for continuous thoracic, lumbar, and sacral paravertebral blocks.

Thin Sharp Needles Around the Dura

rial graft as a result of prior lower-limb revascularization surgery. The avoidance of graft injury or perforation, with possible subsequent bleeding or infection, was the major concern, and whether scar tissue had altered the normal anatomy of the femoral nerve and its surrounding structures was unknown. A two-dimensional, high-resolution portable ultrasound device (L38 Linear probe 5-10 MHz; Sonosite Titan, Bothel, WA) was utilized to identify the vascular graft and the femoral nerve (Fig 1). A Stimuplex D50 (B Braun, Melsungen, Germany) needle and a Stimuplex HNS II (B Braun, Melsungen, Germany) nerve stimulator were used. With the current set to zero, the needle was advanced under direct ultrasonic guidance toward the femoral nerve. Correct needle placement was confirmed with a current of 0.4 mA that resulted in quadriceps twitches. After negative aspiration, 15 mL of lidocaine 1.5% was injected and observed to surround the femoral nerve. Surgical anesthesia was successful, and the patient underwent uneventful surgery and recovery. Direct visualization of neural and perineural structures to facilitate safer regional anesthesia seems intuitive. However, the question of whether the performance of regional anesthesia by use of ultrasound guidance is safer than traditional techniques remains unanswered. Although the evidence is limited or lacking regarding increased safety with ultrasonography, in the case described above, the use of an ultrasound-guided regional anesthesia technique provided safe and effective anesthesia. The use of ultrasound allowed the identification of both the vascular graft and the femoral nerve. Visualization of the structures allowed us to proceed with confidence, as both altered anatomy and needle advancement toward or into the vascular graft could be detected. In conclusion, we present a case in which the use of ultrasound-guided femoral nerve block facilitated a safe and appropriate anesthetic technique for our patient. Whether ultrasound will provide safer regional anesthesia, as it has for vascular access, remains to be seen.5

Electrical nerve stimulation using a stimulating catheter: what is the lower limit?

Objectives: To minimize the risk of intraneural injection when performing nerve blocks, some authors caution against injecting through a needle placed with motor responses observed at nerve stimulator output settings of 0.3 mA or less. We present a case of placing a continuous cervical paravertebral catheter with brisk motor response while stimulating the catheter at 0.05 mA, with no adverse sequelae. Case Report: A 56-year-old man scheduled for rotator cuff repair received a continuous cervical paravertebral block for intraoperative and postoperative pain control. A stimulating catheter was used for the block. During catheter placement, nerve stimulator output was decreased to 0.05 mA at 300 μs and the motor response remained brisk. The patient was not significantly sedated and experienced no pain during placement or with injection of 40 mL of 0.5% ropivacaine through the catheter. Narcotic drugs were not required during surgery, and the block provided excellent postoperative pain control. Catheter position was evaluated by fluoroscopy to further identify the catheters relationship to the brachial plexus. The nerve trunks of C5 and C6 were clearly visible after 1 mL of iohexol (Omnipaque) was injected through the catheter. The catheter was removed the following day. At the follow-up visit 2 weeks later, the patients neurological examination remained unremarkable. Conclusion: We present a single case of successful placement of a stimulating catheter with no neurological injury even when motor response occurred at very low nerve stimulator output settings.

The Use of cervical paravertebral block as the sole anesthetic for shoulder surgery in a morbid patient: a case report

Objectives: The purpose of this case report is to describe the use of the cervical paravertebral block as the sole anesthetic for shoulder surgery in a patient unable to tolerate general anesthesia. Recent literature describes the continuous cervical paravertebral block as an effective alternative to the interscalene block for the management of postoperative pain after shoulder surgery. Case Report: An 85-year-old man with severe respiratory and cardiac disease presented for major shoulder surgery. The patients complex medical history required an anesthetic technique that would avoid general anesthesia and preserve phrenic nerve function. This case report describes, to our knowledge, the first successful use of the continuous cervical paravertebral block as the sole anesthetic for shoulder surgery. Conclusions: Continuous cervical paravertebral block provided excellent surgical conditions and postoperative pain relief for this patient and allowed gradual and intermittent dosing of the catheter and continuous assessment of the anesthetic impact on respiratory function.

A method to estimate the depth of the sciatic nerve during subgluteal block by using thigh diameter as a guide.

Background and Objective: The subgluteal approach is common for sciatic nerve block. Although the surface landmarks are clear, the depth of this nerve at this level is difficult to judge. The purpose of this study is to establish a method of estimating the sciatic nerve depth using the anteroposterior (AP) diameter of the thigh as a marker. Methods: The study was undertaken in 2 phases. Phase 1 entailed review of 100 magnetic resonance images (MRIs) of the pelvis and proximal lower extremity of patients. Measurements were taken of the AP diameter of the thigh at the midpoint of the lesser trochanter and then compared with distances of the sciatic nerves from the skin of the posterior aspect of the thigh at the same level. Phase 2 involved enrolling 40 patients undergoing lower-extremity surgery for whom subgluteal sciatic nerve blocks were indicated. The AP diameters of the thighs were measured from the subgluteal groove to the inguinal groove with the patient in the supine position. Placing the patient in the lateral position, the subgluteal sciatic block was then performed by using a stimulating needle. The distances from the skin at which the sciatic nerves were actually found, as estimated by maximum motor response to stimulus, were noted. Results: Phase 1 showed a mean AP diameter of 18.94 cm ± 2.61 cm (mean ± standard deviation [SD]), mean nerve depth of 6.51 cm ± 1.46 cm (mean ± SD), and a linear regression slope of 0.48. Phase 2 showed a mean AP diameter of 16.28 cm ± 2.73cm (mean ± SD), a mean nerve depth of 6.99 cm ± 1.39 cm (mean ± SD), and a linear regression slope of 0.43. The thigh diameters differed (P < .001) between the groups, but there was no difference in the depth to the sciatic nerve between the 2 groups (P = .07). Conclusions: Comparing phase 1 and phase 2 datasets shows the slopes of linear regression lines are nearly parallel. The clinical data from phase 2 verify the anatomical data collected in phase 1 and show that the sciatic nerve depth to AP diameter ratio is 0.43 or the depth of the sciatic nerve is approximately 43% of thigh diameter if the patient is positioned in the lateral decubitus position.

Paravertebral approach to brachial plexus

1. Boezaart AP, Koorn R, Rosenquist RW. Paravertebral approach to the brachial plexus: An anatomic improvement in technique. Reg Anesth Pain Med 2003;28:241-244. 2. Neal JM. Between innovation and proven value: achieving a balance in technical reporting. Reg Anesth Pain Med 2003;28: 170-171. 3. Bonnet F, Canovas F. Anatomy of the brachial plexus at the new-born and the adult: Macroscopic and histologic structures. In: Alnot JY, Narakas A, eds. Traumatic brachial plexus injuries (Monographie de la Société Française de Chirurgie de la Main;22). Paris: Expansion Scientifique Française, 1996:3-13. 4. Kowalewski R, Schurch B, Hodler J, Borgeat A. Persistent paraplegia after an aqueous 7.5% phenol solution to the anterior motor root for intercostal neurolysis: A case report. Arch Phys Med Rehabil 2002;83:283-285. 5. Borgeat A, Ekatodramis G, Kalberer F, Benz C. Acute and nonacute complications associated with interscalene block and shoulder surgery. Anesthesiology 2001;95:875-880. 6. Borgeat A, Dullenkopf A, Ekatodramis G, Nagy L. Evaluation of the lateral modified approach for continuous interscalene block after shoulder surgery. Anesthesiology 2003;99:436-442. 7. Neuburger M, Rotzinger M, Kaiser H. Elektrische Nervenstimulation in Abhängigkeit von der benutzten Impulsbreite. Anaesthesist 2001;50:181-186.

Pitfalls in regional anesthesia for shoulder surgery

Surgeons are often reluctant to support regional anesthesia for shoulder surgery and other orthopaedic surgery. This is because the sometimes true, but usually perceived slowing down of operating room turnover times, and the perceived potential for added morbidity. The former (time issue) can only be solved by proper management, while the potential for added morbidity can be minimized by doing appropriate blocks for appropriate surgery at the correct times, when really indicated, with the correct equipment and techniques, and avoiding situations that are prone to causing morbidity. This article discusses in detail when it is appropriate to do blocks for shoulder surgery, but more important, when is it not appropriate to do blocks, and how to carefully calculate a risk-benefit ratio and avoid added morbidity.

Evaluation of a Single-Dose, Extended-Release Epidural Morphine Formulation for Pain After Knee Arthroplasty

To The Editor: It is with interest and concern that I read the article entitled “Evaluation of a Single-Dose, Extended-Release Epidural Morphine Formulation for Pain After Knee Arthroplasty,” (2006;88:273-81), by Hartrick et al. The authors should be commended on this well-executed and well-written study. Although the facts speak for themselves (160 of 162 patients experienced adverse events, highlighted …