Partial inferior pubectomy in the delayed repair of pelvic fracture urethral injury: adopting bone-nibbling technique
Ikenna Ifeanyi Nnabugwu1,2, Fredrick Obiefuna Ugwumba1,2, Anthony Alex Ilukwe2
1 Department of Surgery, College of Medicine, University of Nigeria Enugu Campus
2 Department of Surgery, University of Nigeria Teaching Hospital, Ituku-Ozalla, PMB 01129
Ikenna Ifeanyi Nnabugwu, Department of Surgery, College of Medicine, University of Nigeria Enugu Campus, Enugu, Nigeria.
Background: Deployment of wedge inferior pubectomy could be challenging to many urethral surgeons. Objectives: To introduce bone-nibbling technique in accomplishing partial inferior pubectomy (PIP) in a resource-poor setting. And to report medium- to long-term outcome of using the technique. Methods: Five patients (mean age: 38.8years) who presented, over a period of 30 months, with posterior urethral fibrosis from pelvic fracture urethral injury (PFUI) were recruited. One had failed previous attempt at posterior urethral reconstruction elsewhere. The length of urethral defect was from 2 – 4cm. Bone-nibbling technique used in deploying partial inferior pubectomy for delayed repair of PFUI in these patients is described. In addition, the outcomes in the medium to long term of surgical procedures done with this technique are presented. Results: Immediate post-op complications in all were essentially Clavien-Dindo grade I. Peak flowrate assessed 12weeks post-op was between 20ml/s and 23ml/s (mean: 21ml/s). The longest duration of follow-up was 34months and all patients were voiding satisfactorily. Conclusions: Satisfactory and durable outcome can be obtained from nibbling off bits of bone from inferior margin of pubic bone in accomplishing PIP. This is of interest to lower urinary tract reconstructive surgeons who have concerns with chiseling-out wedge of inferior pubis.
Keywords: Bone nibbling; Partial inferior pubectomy; PFUI; Posterior urethra; Urethral anastomosis..
Ann Afr Surg. ****; **(*):***
Conflicts of Interest: None
© 2020 Author. This work is licensed under the Creative Commons Attribution 4.0 International License.
Generally, the management of pelvic fracture urethral injury (PFUI) has continued to evolve, but has remained a challenge. Short-term and long-term outcomes of management are much improved in the last 2 decades than earlier (1). While some authorities practice early realignment, others prefer delayed reconstruction of the stricture that develops with healing of the injury (2). Either group reports acceptable outcomes (3). The repair of the stricture consequent upon the healing of PFUI could be challenging (4) and in the hands of the less experienced surgeon, the outcome of such repair leaves more to be desired. Amongst the contributing factors to the poor outcome of repair is poor access to the site of surgery due to the rigid configuration of the bony pelvis (5). The unyielding bony pelvis limits access to the proximal healthy urethral segment, increases the chances of incomplete excision of the fibrotic urethral segment, compromises the integrity of urethral anastomosis and impairs accomplishment of a tension-free anastomosis (6).
Over the years, some maneuvers have been incorporated into the operative procedure with the primary objectives of improving on access to the surgical site and shortening the gap to be breached after complete excision of the fibrotic segment in a single-stage procedure (7). Some maneuvers that have been deployed include midline splitting of the corpora cavernosa, partial resection of the inferior aspect of the body of the pubic bone (partial inferior pubectomy), and supracrural re-routing of the urethra (7,8). Deployment of any or some of these maneuvers have been reported to result in significant improvement in outcome of such repairs (8,9). When indicated therefore, one or more of these maneuvers are frequently deployed by surgeons with requisite experience (10,11).
A technique for partial inferior pubectomy (PIP) in the delayed repair of PFUI is described (12,13). However, many surgeons of varying duration of practice may not so far have deployed this maneuver because of fear of uncontrollable haemorrhage and concerns about inadvertent injury to other surrounding structures. Nibbling off bits of the pubic bone from the inferior margin may offer same surgical value as chiseling out mass of bone. The controlled engagement of the bone nibbler may increase surgeon’s confidence in the ability to deploy the maneuver without collateral damage.
The aim of this study is to describe the bone nibbling technique of accomplishing partial inferior pubectomy and to give the outcome of its use in our centre so far.
The medical records of 5 men who underwent delayed repair of PFUI deploying bone nibbling technique in accomplishing PIP between March 2017 and December 2019 were retrieved for audit of outcome. Four were primary repairs while 1 was a repeat repair. The mean age of these men was 38.8±7.0years, and the length of the urethral defect was from 2 – 5cm. From the records, the operating time, need for intra-op blood transfusion, immediate post-op complications, need for re-establishment of urinary catheter, and urine peak flow rate 3 months post-op were reviewed.
In addition, institutional records on delayed repair of PFUI in men from April 2008 to January 2016 were retrieved. All 20 cases identified were undertaken without deploying PIP. The men were between 20years and 70years with a mean age of 33.8±12.2years. The median length of urethral defect was 2.5cm (range 1.5 – 5.0cm). From these records, the outcome of repair in terms of need to re-establish suprapubic cystostomy or perform repeated urethral dilatation was determined for comparison with the test cohort. The mean age of patients, mean length of urethral defect and mean units of blood transfused were compared for the 2 groups using ANOVA. Crosstab analysis was used to compare outcomes. Statistical Package for Social Sciences (IBM SPSS Statistics ver. 21.0, Armonk, NY, USA) was used for analysis.
Highlights of bone nibbling technique in deploying PIP: Fig 1 is a combined retrograde urethrogram (RUG) and voiding cystogram (VC) image of a PFUI requiring repair. Briefly, in this repair technique, patient positioning, skin incision and mobilization of the urethra are as described in other literature (5,12,13). The lambda (inverted Y) perineal skin incision gives a better exposure with soft tissue retraction. The urethra is transected just distal to fibrotic segment and the distal segment protected from harm. The fibrotic segment, at this stage, is left attached to the proximal stump of urethral to aide retraction during proximal urethral segment dissection. The proximal corporal bodies are carefully parted in the midline and the dorsal vein coursing inferior to the symphysis pubis is ligated and transected (5) (Figure 1)
With the inferior aspect of the pubic body and adjoining rami visualized, the periosteum is incised and striped using periosteal elevator. Then the inferior pubis is nibbled off using bone nibbler (fig 2) up until adequate room is created for maneuvering the needle holder, and the necessary tissue forceps and suction nozzle during anastomosis. Further proximal urethral stump dissection is done with the aid of antegrade urethral bougie to free enough healthy proximal urethra for anastomosis. Bone wax is applied on the cancellous bone surface for haemostasis. The fibrotic urethral segment is completely excised to expose healthy proximal urethral mucosa (fig 3), and a robust end-to-end urethral anastomosis is accomplished over an appropriate size urethral catheter with relative ease. The rest of the procedure is as described elsewhere (12,13). A corrugated wound drain is always left in place for about 48hours and a firm dressing placed on the perineum after wound closure. Peri-catheter urethrography is done 3weeks post-surgery and urethral catheter stent removed thereafter. Uroflowmetry to assess the post-repair peak flowrate is done 12 weeks post-surgery (Figure 2 and 3).
For the PIP cohort, the mean intra-op blood transfusion rate is 1.4±0.5units per procedure. There is no case of haematoma, deep wound infection, or any complication beyond Clavien-Dindo grade I (14) in the post-operative period. The post-repair peak flowrate has a range of 20 – 23ml/s with a mean of 21ml/s. The longest follow-up period is 34months and all the 5 men have maintained satisfactory urine flow so far. Table 1 is a summary of the cases done adopting bone-nibbling technique in accomplishing PIP.
For the non-PIP group, a mean of 1.6±0.6units of whole blood were transfused per surgical procedure. In about 60% of repairs, there was compelling need to re-establish use of suprapubic catheter for micturition or perform repeated urethral dilatation within 6months post-op. There is little or no evidence of any significant variations in age of patients (p 0.39), length of urethral defect repaired (p 0.05), and in blood transfusion per procedure (p 0.50) between the 2 groups. However, there is some evidence that outcome is better in the PIP cohort (p 0.02) (Table 1).
One of the limitations to ensuring a durable end-to-end anastomosis at the posterior urethra is poor access (5). To overcome this limitation, various specially designed instruments, suture needles and retractors have been introduced for use during this procedure (15). Struggling to complete this anastomosis in the difficult condition of poor access increases the risk of poor tissue handling, and of performing anastomosis of doubtful integrity resulting in poor outcome with its attendant burden on the patient, the surgeon and the health system (6,16). Recurrence of posterior urethral fibrosis requiring further procedures or repeat reconstructions is rather common (17). With the recognition that the first attempt at repair provides the best chance for successful outcome, recurrence is quite worrisome (17,18). Beyond space constraint, urethral length constraint (fig 1) presents another limitation in accomplishing tension free, robust end-to-end anastomosis after excising the fibrotic urethral segment (7). The extent of urethral length challenge is understandably dependent on the length of the excised urethral segment.
Partial inferior pubectomy (PIP) is a maneuver recommended to overcome reasonably both space and urethral length constraints (8). However, this maneuver is not conveniently deployed by many surgeons for fear of encountering uncontrollable bleeding, or damage to some other structure adopting wedge pubectomy technique using rongeurs (2,9). In a yet to be published recent survey of urologists in Nigeria (19), 70.6% and 64.7% of respondents who have witnessed wedge partial inferior pubectomy in delayed repair of PFUI are yet to deploy the maneuver due to concerns of primary haemorrhage and damage to other structures respectively.
PFUI appears generally uncommon limiting experience with its management beyond initial diversion of urine (20,21). Reports from our local and regional settings show that the outcome of surgery for PFUI repair is generally not as good as the outcome of repair of anterior urethral stricture (22). This may be because these PFUI repairs are done without performing PIP, thereby undertaking urethral anastomosis in very challenging circumstances of surgical field and urethral length constraints. Undertaking such urethral anastomosis in the context of space and length constraints will generally lead to suboptimal repair outcome.
The bone-nibbling technique as described here (fig 2) offers an alternative for achieving same goals of improving on surgical access and urethral length constraints. At the same time, it may reduce the concern of inadvertent damage to tissue. The controlled engagement and cutting using the bone nibbler repeatedly from the inferior margin of the pubis may be easier to appreciate and incorporate into surgical practice than the conventional wedge pubectomy. Nibbling off bits of pubic bone does not appear to increase primary haemorrhage. This study reveals that blood transfusion rate is not increased as a result of deployment of this technique in performing PIP. To the benefit of both surgeon and patient, adequate surgical space is created for robust primary urethral anastomosis (fig 3) with improved chances of good and durable outcome (table 1).
Unarguably, deployment of PIP maneuver in surgeries for PFUI repair increases the chances of good surgical outcomes generally (10,23,24). Therefore, urethral reconstructive surgeons who may have concerns with chiseling out mass of pubic bone in accomplishing wedge inferior partial pubectomy could nibble off bits of the bone from the inferior margin instead of undertaking the urethral anastomosis, without PIP, in less than optimal conditions with attendant poor repair outcome.
It is recommended that PIP be deployed in the repair of PFUI-related urethral fibrosis in order to overcome surgical access constraint and healthy urethral length constraint during urethral anastomosis. To accomplish PIP, nibbling off bits of pubic bone from the inferior margin can be adopted where wedge inferior pubectomy cannot be conveniently put to use. Medium- and long-term outcomes show that nibbling off bits of inferior margin of pubic bone does not further increase the risk of PIP, and does offers durable repair outcome.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of Interest
None of the contributing authors has any conflict of interest, including specific financial interests or relationships and affiliations relevant to the subject matter or materials discussed in the manuscript.
The authors acknowledge the assistance of Nweze Ekwuribe in the production of this manuscript.
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