The Application Of Intraoperative Neuromonitoring And Urodynamics In Systematic Nerve-sparing Radical Hysterectomy

Cervical cancer is one of the most frequent malignant tumors in the world, with an obvious higher morbidity. Patients with cervical cancer tend to be younger. Its treatments maily are surgery and radiotherapy. Radiotherapy is good, but can lead to many long complications such as vaginal stenosis and premature ovarian failure. Radical hysterectomy (RH) and pelvic lymphadenectomy greatly improves the survival rates of the patients, meanwhile, they also can bring about many complications such as the urethra/bladder dysfunction, anal/rectal dysfunction and genital/vaginal dysfunction, which have a serious influence on the quality of the patients.The main reason for the above complications is intraoperative injury of the pelvic autonomic nerves (PAN), which contains superior hypogastric plexus, hypogastric nerve, pelvic splanchnic nerve (PSN), pelvic plexus and its bladder branch, rectal branch, dominating the related organs. Half of the cardinal ligament and uterosacral ligament should be dissected during RH and there exit abundant PAN in these two ligaments. Therefore, how to avoid and decrease the injury of PAN is the vital of decreasing such complications during the operation. In order to improve the quality of life of the patients, more attention and researches have been focused on the nerve-sparing procedures. Nerve-sparing radical hysterectomy first appeared in 1960’s, founding that patients had a shorter duration of catheterization and spontaneous urine voiding after operation. Later, Sakamoto introduced the standard preocedure, "Tokyo method" to the world. In 1980, a German expert firstly reported the systematic nerve-sparing radical hysterectomy (SNSRH). Clinical study abroad on SNSRH carried out for many years, evidenced that it can improve the patients’bladder function accoding to the duration of catheterizeation. However, there still exited certain failure rate and clinical inefficient rate because of difficulty in indentifying the nerve during operation and evaluating the bladder function exactly.Identifying the nerve during SNSRH has always been a difficulty because the PAN is so small and connects with the surroundings closely. In early study, experts hoped to find the PAN according to the anatomic marks. However, it was not accurate for many reasons such as intraoperative bleeding, pelvic adhesion and individuan anatomic variations. Later, some researchers began to identify the spared nerve via stimulating the PAN using electricity during operation meanwhile monitoring the vesical pressure. Unfortunately, the vesical pressure can not reflect the nerve’s function directly. The above two method of identifying the nerves were all indirect noes. They can not conlude whether the nerves were preserved successfully. Therefore, we must work out some way to find the nerve directly during the operation.Intraoperative neuromonitoring (IONM) has been a valuable part of surgical procedures for over 20 years and now it has its own intraoperative monitoring system and has been an important part of modern medicine. IONM provides critical information to the surgeon allowing preserving and protecting the nerve or avoidance of neural insults. Intraoperative electromyographyic (EMG) monitoring and nerve-muscle triggered EMG are two of the most common tests. Intraoperative electrical stimulation is one of the neurological techniques. Stimulating the nerve dominating the related muscle can make muscle to produce evoked potentials. Recording the triggered EMG can reflect the the completence of the nerve pathway and its function objectively and sensitively. Now it is common in department of neurosurgery and spinal orthopedics.Therefore, the first part of this study imagines to monitoring the evoked potentials produced by vesical detrusor while stimulating the PSN using IES technique, and then records the triggered EMG to know the completence of the nerve pathway and its function to confrm successful merve preserved finally.Urodynamics is a new method of lower urinary tract examination which developed in recent years. It is the noly reliable diagnosis method of lower urinary tract disorders. Dding research on urodynamics, not only has impotant practical value in diagnosing and treating the voiding dysfunction diseases, but also has great scientific value in mastering the physiological and pathological conditionsof the voiding. Therefore, the second part of this study intends to evaluate the postoperative bladder function via comparing the urodynamic results after SNSRH and RH to know the related mechanicsm of bladder dysfunction and its recovery, further to confirm the important role of IONM in confirmation of the nerve preservation important and prognose the patients’bladder function condition after operation. Hope that it can make a standard operation steps for the SNSRH and improve the success rate and then finally give a better quality of life to the cervical caner patients. [Purpose]Researches evidenced that SNSRH can improve the serious bladder dysfunction caused by RH. But the identifying and confirming of the nerves during the operation limited the development and genelization of the SNSRH. This study intended to monitor the evoked potentials produced by vesical detrusor while stimulating the root of the PSN trunk, just the originate of the parasymphathetic nerve pathway, using IES technique, and then record the triggered EMG to know the completence of the nerve pathway and its function to confrm successful merve preserved finally.[Method]54 cases of cervical caner and endometrial cancer meeting the inclusion criteria were chosen.23 cases had relative complete urodynamic results after operation of the 27 patients who wanted to receiving SNSRH with voluntary choice belonged to Group SNSRH. Another 20 cases had relative complete urodynamic results after operation of the 27 patients who wanted to receiving RH with voluntary choice belonged to Group RH. Group RH received the traditional RH operation and there was no electrical stimulation during the operation. Group SNSRH received the SNSRH operation and IES were performed on the root of the PSN trunk in all cases using constant monophasic rectangular pulse current maintaining for 10s with the frequency of stimulation and the duration of the pulse 10Hz and 1.0ms while recording the EMG activity of the vesical detrusor after resection of the uterus.[Results]Potentials were evoked from the vesical detrusor when stimulating the root of the PSN trunk with the stimulation thresholds ranged from 10mA to 50mA (average 33mA) in 18 of 23 patients in Group SNSRH, which was defined as IES-positive Group. Among the 18 cases,16 got EMG activities when stimulating bilateral PSN, but only unilateral PSN could be detected in the remaining 2 cases. The recording EMG activities were of atypia and desynchroneity, manifesting as biphasic or polyphasic, continuous or uncontinuous with different amplitudes. For the remaining 5 cases, we defined as IES-negative Group because there exited no EMG response when stimulating the bilateral PSN with the stimulating current of 75 mA.[Conclusion]In SNSRH, monitoring the evoked potentials produced by vesical detrusor while stimulating the root of the PSN trunk and then recording the triggered EMG is an effective way to know the completence of the nerve pathway and its function and then confirm successful merve preserved finally.Part Two Evaluation of bladder function using urodynamics after SNSRH[Purpose]Evaluating the bladder function after RH according to subjective symptoms of the patients and the duration of catheterization has many limitations. The postoperative duration of catheterization can be influenced by some factors and can only reflect the early conditions of the bladder. Accurate assessment is difficult. Urodynamics can evaluate the bladder voiding function objectively according to measureing the detrusor pressure. Therefore, the part of the study intends to evaluate the postoperative bladder function via comparing the urodynamic results after SNSRH and RH to know the related mechanicsm of bladder dysfunction and its recovery, further to confirm the important role of IONM in confirmation of the nerve preservation important and prognose the patients’bladder function condition after operation. [Method]All patients in Group SNSRH and Group RH received the urodynamic examinations before operation and three months and six months after operation, including the uroflowmetry, urethral pressure profle and filling cystometry. Then compare the results of Group SNSRH IES(+) and RH, Group SNSRH IES(-) and RH, Group IES(+) and IES(-).[Results]1. RH can bring serious bladder dysfunction Comparing with the preoperative and postoperative urodynamics of Group RH, we found that the corrected maximum flow rate three and six months after operation were significantly lower then that of preoperation. The residual volme three and six months after operation were significantly more then that of preoperation. Compared with preoperation, the maximum vesical compliance decreased significantly. No patient voided with abdominal pressure before operation, whereas 50% and 40% patients had abdominal pressure to assist urination three and six months after operation respectively. There was no significance about the maximum urethral pressure before and after operation. So did the vesical first desir volume, but with an increasing tendency. The maximun cystometric capacities three and six months after operation were significantly higher then that of preoperation, but they all were within normal range. All these indicated that the bladder dysfunction after RH was mainly due to the parasympathetic nerve injury. Related urodynamic index changes contained decreased maximum flow rate, increased residual volume, decreased maximum vesical compliance and obvious abdominall pressure voiding phenolmenon. Till six months after operation, there was no improvement. Part of the patients had bladder insensitive but not obvious sensory dysfunction. The urethal pressure were normal before and after operation and no urinary tract dysfunction were found. 2. SNSRH IES(+) can improve the bladder dysfunction caused by RH effectively Comparing with the preoperative and three months postoperative urodynamics of Group SNSRH(+), we found that there were no significance in the corrected maximum flow rate, residual volume and maximum vesical compliance, but the differences were smaller than that of Group RH. Related results demonstrated that there was a slight improvement three months after operation but still with obvious bladder dysfunction. The proportion of abdominal pressure voiding before and three months after operation were 5.6% and 0% respectively with no significant difference, indicating that the situation had been significantly improved. In the sixth month after operation, the corrected maximum flow rate increased back to 1.66mL/s, the residual volume decreased back to 34.38mL and no patient had abodominal pressure voiding. Compared with that of three months after operation, a further and obvious improvement was found. And there were no signicant differentces when comparing preoperative and six months postoperative. It can be concluded that bladder function was improved in a gradually tendancy and recoveried to the preoperative status till six months after operation. SNSRH can improve the bladder dysfunction caused by RH effectively. Besides, while the nerves were successfully preserved, there still exited some injury and it would take three months to recover. Data still demonstrated that the vesical first desir volume changed to a certain extent, a less insentitive than preoperative, with a improve tendancy six months after operation. There was no significant differentce in the maximum cystometric capacity before and after operation, but still had a tendancy of recovering to the preoperative status, indicating that SNSRH can improve the patients’bladder sensory function to a certain extent, but not obvious.3. The operation success rate determined by IES-positive was the same as clinical efficacy evaluated by urodynamics Comparing the urodynamic results of Group IES-positive and IES-negative before and after operation, we found that the changing tendancy of urodynamic index of Group-IES was similar to that of Group SNSRH, whereas the Group IES-negative similar to that of Group RH. The corrected maximum flow rate, residual volume, maximum vesical compliance and abdominal pressure voiding improved gradually to the preoperative status till six months after operation, indicating that IES-positive Group patients indeed spared the nerves successfully and improved the bladder dysfunction caused by RH effectively. However, for Group IES-negative, except the maximum urethral pressure and bladder sensory function index, the remaining urodynamic index indicated serious bladder dysfunction and worsed with the time. Till the six month postoperative, no improvement was found indicating that IES-negative patients failed to preserve the nerve and there were still serious postoperative bladder dysfunction.4.18 cases of IES-positive patients indeed improved the bladder function effectively, while another 5 cases of IES-negative patiens failed to improve its bladder function. There was a high consistence between the operation success rate determined by IES-positive and the clinical efficacy evaluated by urodynamics.[Conclusion]1. RH can bring serious bladder dysfunction, which mainly cause by parasympathetic nerve injury.2. There was a slight improvement three months after SNSRH IES(+) but still with obvious bladder dysfunction. There exited a gradually tendancy and recoveried to the preoperative status till six months after operation. SNSRH can improve the bladder dysfunction caused by RH effectively. Besides, while the nerves were successfully preserved, there still exited some injury and it would take three months to recover.3. The changing tendancy of urodynamic index of Group IES(+) was similar to that of Group SNSRH, whereas the Group IES(-) similar to that of Group RH. IES-positive Group patients indeed spared the nerves successfully and improved the bladder dysfunction caused by RH effectively. However, for Group IES-negative, there still exited serious bladder dysfunction postoperatively and worsed with the time. Till the six month postoperative, no improvement was found indicating that IES-negative patients failed to preserve the nerve and there were still serious postoperative bladder dysfunction.4. There was a high consistence between the operation success rate determined by IES-positive and the clinical efficacy evaluated by urodynamics. It confirmed the important role of IONM in confirmation of the nerve preservation important in further and prognosed the patients’bladder function condition after operation.