The Anatomical Distribution of the Pudendal Nerve Block Injection: A Cadaveric Study.

OBJECTIVE: The objective of this study was to assess the accuracy of commonly used injection locations of the pudendal nerve block by examining the proximity of the injected dye to the pudendal nerve in a cadaveric model. METHODS: Pudendal block injections at 4 sites were placed transvaginally on 5 cadaveric pelvises. These sites were 1 cm proximal to the ischial spine (black dye), at the ischial spine (red dye), 1 cm distal to the ischial spine (blue dye), and 2 cm lateral and 2 cm distal to the ischial spine (green dye). The cadavers were dissected via a posterior approach. RESULTS: We measured the shortest distance from the center of the dye-stained tissue to the pudendal nerve. As expected, the injections at the ischial spine (red) resulted in a distribution of dye closest to the pudendal nerve, averaging 3.0 ± 0.95 mm. Dyes at other sites were close to the nerve: 3.1 ± 1.00 mm (black), 3.6 ± 1.14 mm (blue), and 4.05 ± 1.28 mm (green). CONCLUSIONS: Regardless of the injection site, all dyes were close the pudendal nerve, indicating accuracy. We observed wide variation in the dye distribution even though all injections were performed by the same provider, implicating lack of precision. Based on our findings, we propose that the most effective injection location is at the ischial spine because it is the closest to the pudendal nerve; however, all injections were within 4 mm of the pudendal nerve, suggesting that only 1 to 2 injections may be sufficient.

Comparison of Two Methods: Spinal Anesthesia and Ischiorectal Block on Post Hemorrhoidectomy Pain and Hospital Stay: A Randomized Control Trial.

OBJECTIVE: Hemorrhoidectomy is one of the most common hemorrhoid surgery. Many areas are innervated by nerves, and this makes the surgery to be very painful. Various anesthetic methods have been proposed, and the number of investigations and procedures demonstrated the absence of a reliable method for reducing pain. This study compares the cavity ischiorectal block with spinal anesthesia in reducing postoperative pain, analgesic consumption, and hospital stay. RESEARCH DESIGN: This study is a randomized control trial carried out on seventy patients sampled. Thirty-five (35) among them were placed in spinal anesthesia group, and the other 35 were placed in the ischiorectal block group. According to the study, questionnaire was designed in such a way that postoperative variables such as postoperative pain, analgesic consumption, changes in blood pressure, heart rate and hospital stay in both groups were evaluated and compared. CLINICAL TRIAL REGISTRATION: IRCT2015111616516N3 ( http://en.search.irct.ir/search?query=IRCT2015111616516N3 ) Results: In this study, the pain scores on Visual Analogue Scale (VAS) at 0, 6, 12, and 24 hr for spinal anesthesia group after surgery were 0, 3.08 ± 0.78, 2.05 ± 1.02, 1.11 ± 0.83, respectively (p < 0.05). That of ischiorectal blocks were 0.98 ± 0.25, 1.57 ± 0.81, 0.91 ± 0.91, and 0.63 ± 0.31 respectively, which indicated lesser pain after surgery in the ischiorectal block at 6, 12, and 24 hr. In this study, out of the 35 patients that underwent spinal anesthesia, 28 patients (80%) were hospitalized in the first 6 hr, 13 patients (37.1%) in the second 6 hr, 3 patients (8.6%) in the second 12 hr after surgery. For patients under the ischiorectal block, the number of patients hospitalized were 13 patients (37.1%), in the first 6 hr, 4 patients (11.4%) in the second 6 hr, and 1 (2.9%) were hospitalized in the second 12 hr after surgery (p < 0.05). CONCLUSION: Ischiorectal blocks causes less pain, require fewer painkillers, and reduces the hospital stay after surgery than spinal anesthesia.

Proximity of uterosacral ligament suspension sutures and S3 sacral nerve to pelvic landmarks.

INTRODUCTION AND HYPOTHESIS: To describe the relationships between pelvic bony landmarks to points along the third sacral nerve and to uterosacral ligament suspension sutures. METHODS: Three transvaginal uterosacral ligament suspension sutures were placed bilaterally in unembalmed female human cadavers. The third sacral nerve was marked at the foramen (S3a) and at two additional points at 1-cm intervals along its course caudally (S3b, S3c). Three bony pelvic landmarks were identified and marked, including the ischial spine, pubic symphysis, and coccyx. Distances from each landmark to each suture and nerve point were measured. The distance from each landmark to each S3 nerve point was extended radially, encompassing an arbitrary zone in which sutures may be placed and thus where nerve injury may occur. Zones of potential nerve injury included: zone A (closest to the sacral nerve root), zone B, and zone C (closest to the landmark). Descriptive statistics were used and comparisons were made using Student's t test and ANOVA. RESULTS: Ten cadaver specimens were dissected. For the ischial spine, the distances to points S3a, S3b, and S3c were 6.3, 5.4, and 4.6 cm respectively. Approximately two thirds of the sutures were noted beyond zone C, indicating a potentially increased risk of nerve injury with suture placement in zones farthest from the ischial spine given their proximity to the sacral nerve. CONCLUSIONS: Using the ischial spine as a landmark, increased sacral nerve injury could result from suture placement beyond the mean distance of 4.6 cm from the ischial spine. The use of bony landmarks in avoiding sacral nerve injury may be as important as suture depth and angle of suture placement.

The ischiatic region: normal and MRI anatomy.

AIM: The aim of this study was to describe the anatomy correlated to the normal magnetic resonance imaging (MRI) images of the proximal thigh region and the ischial tuberosity. METHODS: MRI coronal and axial sequences were obtained from 20 asymptomatic volunteers (10 male and 10 female) aged 20 to 38 years (mean age: 28 years), and then they were compared with 2 anatomical dissections and 7 cryosections of 6 cadaver thighs. RESULTS: The anatomical specimens were directly correlated with MRI scans. From the comparison it could be seen how the axial MRI sequences well outlined the sciatic nerve, usually observed oval in shape with moderate signal intensity, and thus easily detectable from other surrounding organs. Other structures were also identified by axial images: the ischial tuberosity, the proximal origin of the hamstring muscles arising from the ischium and the related bursae, the gluteus maximus and its bursa, the quadratus femoris and its inconstant bursa, a triangular adipose body and vessels. Coronal scans also showed well the hamstring muscles, both in length and thickness. CONCLUSIONS: Both MRI images and cadaver dissections showed the ischial tuberosity as an interesting intersection area that could be delimited as follows: on the dorsal border the gluteus maximus and its bursa, on the dorso-medial side the hamstring muscle origin, and on the antero-lateral side the quadratus femoris muscle with its inconstant bursa and the ischial tuberosity. These anatomical and MRI descriptions are very useful to give a contribution to the right explanation of sciatic symptoms caused by those sports specifically overloading the hamstring muscles. Frequently, in fact, in these athletes a sciatic syndrome arise drawing the physician's attention to the lumbosacral joint or to the sciatic nerve course near the piriformis muscle. Another very important site where the sciatic symptoms can rise, indeed, could also be found in the hamstring muscle region, where the nerve run under the gluteus maximus beside the ischiatic bone. Athletes who manifest notorious muscle overload in this anatomical region usually show sciatic pain symptoms that are not to be related with pathologies of the lumbosacral junction nor to relationships of the sciatic nerve with the piriformis muscle but rather to relationships that this nerve acquires with either gluteal muscles as well as with muscles of the underneath ischiatic region.

Ischiorectal fossa block decreases posthemorrhoidectomy pain: randomized, prospective, double-blind clinical trial.

PURPOSE: Hemorrhoidectomy can be associated with severe pain in the immediate postoperative period. The aim of this study was to assess the efficacy of a preemptive local anesthetic, ischiorectal fossa block, in the reduction of pain and analgesic requirements after hemorrhoidectomy. METHODS: All patients were suitable for an established day surgery hemorrhoidectomy protocol. Immediately before surgery patients were randomly assigned either to receive (Group 1) or not receive (Group 2) the local anesthetic block. All other aspects of surgery and anesthesia were standardized. Nursing staff assessed pain at 30 minutes and 2, 4, and 24 hours postoperatively using a visual analog scale (1-10, where 1 represented no pain and 10 represented the worst pain imaginable). Analgesic requirements also were recorded at these times. Both the patients and the nursing staff were blinded to which local anesthetic protocol had been used. RESULTS: Twenty patients were enrolled in the trial. Ten patients were randomly assigned to Group I and ten to Group 2. Mean pain scores for Group 1 (anal block) at 0.5, 2, 4, and 24 hours were 1.5, 1.8, 2.1, and 2.5, respectively, compared with Group 2, with mean pain scores of 3.4, 3.4, 3.9, and 5.1. These differences were statistically significant. Patients in Group 1 used less analgesia in the first 24 hours postoperatively than those in Group 2. CONCLUSION: The use of a preemptive local anesthetic, ischiorectal fossa block, is associated with a significant decrease in pain and analgesia requirements after hemorrhoidectomy.

[Alcock's canal syndrome and perineal neuralgia]. / Syndrome du canal d'Alcock et névralgie périnéale.

Fifteen cases of perineal neuralgia are reviewed, the lesion arising from a canal syndrome due to compression of the pudendal nerve in the ischiorectal fossa (Alcock's canal syndrome). The clinical characteristic of the pain syndrome was its postural nature with the existence of a true Tinel sign (increased pain on sitting). Diagnosis was confirmed in all cases by a perineal electrophysiological which showed peripheral neurogenic signs on examination of perineal muscles and an increase in sacral evoked potentials latencies (latency of bulbocavernous or clitorido-anal reflexes, cortical somesthetic evoked potential from pudendal nerve). Treatment was infiltration of cortisone derivatives into the pudendal nerve canal, under CT guidance because of the difficulty of infiltrating the pudendal nerve by an external perineal approach. Results were satisfactory in 9 of the 15 patients.

Free amino acids in the spinal cord, ganglia and ischiadic nerve of the dog after ligature of the abdominal aorta.

The effect of occlusion of the abdominal aorta for 10, 20 and 40 minutes on the concentration of aspartic and glutamic acids, glutamine, glycine, alanine and gamma-amino butyric acid in the anterior and posterior horns of the lumbosacral spinal cord was studied in the dog, further, concentration of amino acids (except GABA) in lumbosacral spinal ganglia and in the ischiadic nerve following 40 minutes of occlusion. The changes were most marked after 40 minutes of occlusion with a rise in concentration of alanine, glutamine and glutamic acid in the dorsal part of grey matter. Striking was also the simultaneous elevated concentration of Glu and Gln in spinal ganglia. The significance of these changes is discussed from the aspect of metabolism and function of nerve cells. Under physiological conditions the free amino acid pool in the central nervous system remains essentially constant. Under pathological conditions, however, like ischemic-hypoxic states, various changes occur.